Manufacturing method of cool-feeling non-woven fabric with embedded phase change capsules

Abstract

The invention discloses a manufacturing method of a cool-feeling non-woven fabric embedded with phase change capsules, and belongs to the technical field of non-woven fabrics, and the manufacturing method comprises the following steps: S1, granulating a skin layer component to obtain skin layer particles; s2, granulating the core layer component to obtain core layer particles; s3, the skin layer particles and the core layer particles are extruded and sprayed out through a double-layer concentric spinneret plate to form concentric fibers; s4, after being extruded, the concentric cellosilk is heated and stretched to obtain phase change cellosilk, and in the stretching process, the skin layer component is thinned, and the internal phase change microcapsules are extruded by the core layer component and migrated to the surface of the skin layer component; s5, cutting, opening and carding the phase-change fibers, laying the phase-change fibers into a net, and reinforcing and forming the phase-change fibers to obtain the cool-feeling non-woven fabric; the heat transfer efficiency between the human body and the phase change microcapsules can be improved, so that the heat management effect of the cool non-woven fabric is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of non-woven fabrics, and in particular to a method for manufacturing a cooling non-woven fabric with embedded phase-change capsules. Background Art

[0002] Non-woven fabrics are widely used in disposable sanitary products such as disposable masks, medical protective clothing, diapers, sanitary napkins, etc. Most of these products need to be in direct contact with the human body. Users are prone to feel more stuffy when using these products in hot weather. In order to solve the defects of these products, the current common practice is to combine non-woven fabrics with phase change materials and other materials that can produce a cooling sensation to make cooling non-woven fabrics. Cooling non-woven fabrics usually mix phase change materials into the coating and then apply them on the surface of the non-woven fabric to form a layer of heat-absorbing and cooling coating on the surface of the cooling non-woven fabric. Based on the special fiber structure of the non-woven fabric, the coating has poor adhesion to the surface of the non-woven fabric, making the coating easy to fall off during use. Therefore, some cooling non-woven fabrics are made by mixing phase change materials or phase change microcapsules with synthetic resins and then through processes such as spinning. This type of cooling non-woven fabric does not have the hidden danger of coating falling off, but most of the phase change materials or phase change microcapsules in the fibers are wrapped inside, and the heat transfer efficiency is low, which easily leads to poor thermal management effect of the cooling non-woven fabric.

[0003] Based on the above situation, the Chinese patent with publication (announcement) number CN118048729A discloses a phase-change polyurethane melt-blown non-woven fabric and a preparation method thereof, comprising the following steps: preparing a prepolymer from polyethylene glycol, an aromatic diisocyanate and an antioxidant, conducting a prepolymerization reaction with N,N-dimethylformamide as a solvent under a nitrogen atmosphere, then adding an aromatic chain extender to react to obtain a phase-change polyurethane solution, drying the phase-change polyurethane solution to obtain phase-change polyurethane chips, adding the polyurethane chips to the barrel of a melt-blown spinning machine, extruding them through a screw, and then drawing them into fibers under high-speed hot air, thereby forming a phase-change polyurethane melt-blown non-woven fabric by hot melt bonding.

[0004] The above patent document discloses a non-woven fabric with polyethylene glycol as a phase change material. During the production process of the non-woven fabric, polyethylene glycol is mixed into the reaction system for polyurethane synthesis, so that polyethylene glycol is dispersed inside the polyurethane generated by the reaction. In the polyurethane fibers that make up the non-woven fabric, some polyethylene glycol will adhere to the surface of the polyurethane fibers. Since polyethylene glycol is water-soluble, during the washing of the polyurethane fibers or the use of the non-woven fabric, the polyethylene glycol on the surface of the polyurethane fibers is easily dissolved in liquids such as water and sweat and lost, which makes the thermal management effect of the non-woven fabric worse. Even if the polyethylene glycol is first made into microcapsules and then used in the production of the non-woven fabric, although the loss of polyethylene glycol on the surface of the polyurethane fibers can be avoided, the efficiency of heat absorption by the polyethylene glycol inside the polyurethane fibers is low, and the thermal management effect of the non-woven fabric is still relatively poor. Therefore, there is still room for improvement in this non-woven fabric. Summary of the Invention

[0005] In view of the technical defects existing in the background technology, the present invention proposes a method for manufacturing a cooling non-woven fabric with embedded phase change capsules, which solves the above technical problems and meets practical needs. The specific technical solution is as follows: A method for manufacturing a cooling nonwoven fabric with embedded phase change capsules, comprising the following steps: S1. Mixing polyethylene resin, phase change microcapsules, calcium carbonate, and stearate to obtain a cortex component, adding the cortex component to a twin-screw extruder for blending and granulation to obtain cortex particles; S2, mixing polypropylene resin and core layer additives to obtain core layer components, adding the core layer components into a twin-screw extruder for blending and granulation to obtain core layer particles; S3, extruding the skin layer particles and the core layer particles through two extruders respectively and spraying them through a double-layer concentric spinneret to form concentric fiber filaments; Among them, the concentric fiber filaments are composed of core components and cortex components from the inside to the outside; S4. After the concentric fibers are extruded, they are kept warm in an environment of 90-110°C and heated for stretching. During the stretching process, the skin component becomes thinner and the internal phase change microcapsules are squeezed by the core component and migrate to the surface of the skin component. The stretched concentric fibers are cooled and shaped to obtain phase change fibers. S5. The phase change fiber yarns are cut, opened, and combed, and then laid into a fiber web, and the fiber web is reinforced and formed to obtain a cool non-woven fabric.

[0006] As a further technical solution of the present invention, in step S1, the phase change microcapsules need to be surface treated to reduce the surface energy before being mixed with the polyethylene resin. The specific operation is as follows: the phase change microcapsules and the silane coupling agent are mixed in a mass ratio of 100:(0.5~2), and then put into an ethanol solution for ultrasonic treatment for 20~40 minutes, and then filtered and the solid product is dried to obtain the surface-treated phase change microcapsules.

[0007] As a further technical solution of the present invention, the structure of the phase change microcapsule is composed of a capsule shell on the surface wrapping the internal phase change material, the capsule shell is selected from one of polyurethane resin and melamine resin, and the phase change temperature of the phase change material is 20~30℃.

[0008] As a further technical solution of the present invention, the polyethylene resin includes linear low-density polyethylene and low-density polyethylene, and the cortical component includes the following components by mass percentage: linear low-density polyethylene 45%~65%, low-density polyethylene 15%~25%, phase change microcapsules 15%~25%, calcium carbonate 3%~5%, and stearate 1%~2%.

[0009] As a further technical solution of the present invention, the stearate is selected from one or more of calcium stearate, magnesium stearate, and zinc stearate.

[0010] As a further technical solution of the present invention, the core layer additive comprises polyethylene / 1-hexene copolymer elastomer and styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride; The core layer components include the following components by mass percentage: 89% to 94% of polypropylene resin, 5% to 8% of polyethylene / 1-hexene copolymer elastomer, and 1% to 3% of styrene-ethylene-butylene-styrene copolymer grafted maleic anhydride.

[0011] As a further technical solution of the present invention, the mass ratio of the cortex component to the core component in the concentric fiber yarn is 1:(2~3).

[0012] As a further technical solution of the present invention, in step S4, the concentric fiber filaments are stretched 2 to 3 times to form phase change fiber filaments, and the stretching process includes three stretching steps, wherein the temperature of the first stretching step is 90 to 100°C and the stretching ratio is 1.2 to 1.3 times, the temperature of the second stretching step is 95 to 105°C and the cumulative stretching ratio is 1.5 to 2 times, and the temperature of the third stretching step is 100 to 110°C and the cumulative stretching ratio is 2 to 3 times.

[0013] As a further technical solution of the present invention, the cooling non-woven fabric has a gram weight of 20-100 gsm.

[0014] The beneficial effects of the present invention are: The phase change fiber filaments of the present invention are composed of a core layer component and a cortex component from the inside out. The phase change fiber filaments form a melting temperature gradient and a rigidity gradient from the inside out. During the stretching process of the phase change fiber filaments, the phase change microcapsules tend to migrate to the surface area with low shear resistance due to the weak interface bonding with the resin matrix in the cortex component. At the same time, during the thinning process of the cortex component, the phase change microcapsules will be squeezed by the core layer component and further migrate to the surface of the cortex component, so that the phase change microcapsules are concentratedly distributed and embedded in the outer surface of the phase change fiber filaments. During the use of the cooling non-woven fabric made of phase change fiber filaments, the human body can directly contact the phase change microcapsules, which is beneficial to improve the heat transfer efficiency, thereby improving the thermal management effect of the cooling non-woven fabric. DETAILED DESCRIPTION

[0015] The following describes the implementation of the present invention in conjunction with relevant embodiments. The implementation of the present invention is not limited to the following embodiments, and the present invention relates to relevant necessary components in this technical field and should be regarded as a well-known technology in this technical field, which can be known and mastered by technical personnel in this technical field.

[0016] A method for manufacturing a cooling nonwoven fabric with embedded phase change capsules, comprising the following steps: S1. Mixing polyethylene resin, phase change microcapsules, calcium carbonate, and stearate to obtain a cortex component, adding the cortex component to a twin-screw extruder for blending and granulation to obtain cortex particles; S2, mixing polypropylene resin and core layer additives to obtain core layer components, adding the core layer components into a twin-screw extruder for blending and granulation to obtain core layer particles; S3, extruding the skin layer particles and the core layer particles through two extruders respectively and spraying them through a double-layer concentric spinneret to form concentric fiber filaments; Among them, the concentric fiber filaments are composed of core components and cortex components from the inside to the outside; S4. After the concentric fibers are extruded, they are kept warm in an environment of 90-110°C and heated for stretching. During the stretching process, the skin component becomes thinner and the internal phase change microcapsules are squeezed by the core component and migrate to the surface of the skin component. The stretched concentric fibers are cooled and shaped to obtain phase change fibers. S5. The phase change fiber yarns are cut, opened, and combed, and then laid into a fiber web, and the fiber web is reinforced and formed to obtain a cool non-woven fabric.

[0017] In order to solve the defects of cool non-woven fabrics such as easy peeling of the coating and difficulty of the internal phase change material in performing thermal management, the present invention provides a cool non-woven fabric in which phase change microcapsules migrate and are embedded on the fiber surface, so that the cool non-woven fabric does not need to worry about the coating falling off during use. At the same time, the phase change microcapsules on the fiber surface can better perform thermal management through the internal phase change material, thereby improving the thermal management effect of the cool non-woven fabric.

[0018] In step S1 of the present invention, the cortex component is composed of polyethylene resin, phase change microcapsules, calcium carbonate, and stearate. The phase change microcapsules are wrapped with paraffin, polyethylene glycol or a phase change material mixed with multiple phase change materials. The polyethylene resin includes linear low-density polyethylene and low-density polyethylene. The cortex component includes the following components by mass percentage: linear low-density polyethylene 45%~65%, low-density polyethylene 15%~25%, phase change microcapsules 15%~25%, calcium carbonate 3%~5%, and stearate 1%~2%; the cortex component is located on the outer surface of the phase change fiber filament, so that the cortex component can be in direct contact with the human body during the use of the cool non-woven fabric, thereby more efficiently performing heat management through the internal phase change microcapsules, thereby improving the cool feeling of the cool non-woven fabric.

[0019] Furthermore, the melting temperature of polyethylene resin is low, and it can be used as a bonding component in the process of phase change fiber filaments being reinforced into cool non-woven fabrics by hot rolling, hot air, etc.; the structure of the phase change microcapsule is composed of a capsule shell on the surface wrapping the internal phase change material, and the capsule shell is selected from one of polyurethane resin and melamine resin, and the phase change temperature of the phase change material is 20~30℃. The phase change microcapsules are dispersed in the cortical components, and the human body can more efficiently exchange heat with the phase change material in the phase change microcapsule after contacting the cool non-woven fabric, thereby improving the thermal management effect of the cool non-woven fabric; the calcium carbonate is preferably nano-scale calcium carbonate modified with stearic acid, and the calcium carbonate can be modified by the currently common dry method, wet method or In-situ modification, preferably in-situ modification, the modification of calcium carbonate adopts the currently disclosed technology, which will not be elaborated here. Calcium carbonate is an inorganic filler, which can enhance the dispersion force of polyethylene resin under shear action, inhibit the agglomeration of phase change microcapsules, and improve the dispersibility of phase change microcapsules in polyethylene resin melt, and can promote the migration of phase change microcapsules to the fiber surface; stearate is selected from one or more of calcium stearate, magnesium stearate, and zinc stearate. Stearate is preferably a mixture of calcium stearate and magnesium stearate. Calcium stearate has the effects of lubrication and reducing melt viscosity. Magnesium stearate interacts with the polar groups on the surface of the phase change microcapsules through the hydrophobic end to promote the migration of the phase change microcapsules to the fiber surface.

[0020] Furthermore, the polyethylene resin is a mixture of linear low-density polyethylene and low-density polyethylene. The low-density polyethylene can reduce the melting temperature of the cortical component and the fluidity after melting. During the stretching process of the concentric fiber filaments, the increase in the fluidity of the cortical component is conducive to the further migration of the phase change microcapsules to the surface, thereby making the phase change microcapsules more concentratedly distributed on the cortical surface of the phase change fiber filaments, improving the efficiency of the cool non-woven fabric in thermal management through the phase change microcapsules, and improving the cool feeling of the cool non-woven fabric.

[0021] Furthermore, phase change microcapsules are made using common microcapsule encapsulation technology. In the phase change microcapsules, polyurethane resin or melamine resin is used as the shell material and the phase change material is used as the core layer material. The phase change microcapsules are preferably made based on the emulsification method. The specific operation is: the shell material is dissolved in solvent A to form an outer phase, and the core layer material is dissolved in solvent B to form an inner phase, and solvent A and solvent B are immiscible with each other. After mixing the outer phase and the inner phase, a suitable emulsifier is added to emulsify them into an emulsion, and the outer phase is used as a continuous phase in the emulsion, and the inner phase is used as a dispersed phase in the emulsion. Then, the shell material in the outer phase is solidified and the core layer material is wrapped inside by heating, cooling, cross-linking and curing, and then filtered, washed, and dried to obtain phase change microcapsules with the shell material wrapped in the core layer material.

[0022] Furthermore, in step S1, the phase change microcapsules need to be surface treated to reduce the surface energy before being mixed with the polyethylene resin. The specific operation is as follows: the phase change microcapsules are mixed with the silane coupling agent in a mass ratio of 100: (0.5~2), and then put into an ethanol solution for ultrasonic treatment for 20~40 minutes, and then filtered and the solid product is dried to obtain the surface-treated phase change microcapsules; after the phase change microcapsules are surface-modified by the silane coupling agent, it is beneficial to disperse the phase change microcapsules more evenly in the cortical component, and the interfacial bonding force between the phase change microcapsules and the polyethylene resin can be reduced. During the stretching process of the concentric fiber filaments, the softened cortical component undergoes flow deformation under the action of the axial tensile force, and the phase change microcapsules tend to migrate to the surface area with low shear resistance due to their weak interfacial bonding with the resin matrix, thereby making the phase change microcapsules more concentratedly distributed on the cortical surface of the phase change fiber filaments, further improving the efficiency of the cool non-woven fabric in thermal management through the phase change microcapsules, and improving the cool feeling of the cool non-woven fabric.

[0023] In step S2 of the present invention, the core layer component is composed of a polypropylene resin and a core layer auxiliary agent, the core layer auxiliary agent includes a polyethylene / 1-hexene copolymer elastomer and a styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride, and the core layer component includes the following components by mass percentage: 89% to 94% of polypropylene resin, 5% to 8% of polyethylene / 1-hexene copolymer elastomer, and 1% to 3% of styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride; the polyethylene / 1-hexene copolymer elastomer is used as a plasticizer in the core layer component. During the stretching process of the concentric fibers, the polyethylene / 1-hexene copolymer elastomer can reduce the modulus of the polypropylene resin, making the core layer component more susceptible to plastic deformation and avoiding delamination inside the fibers during the stretching process. The styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride serves as a compatibilizer in the core layer component, which can improve the compatibility between the polypropylene resin and the polyethylene / 1-hexene copolymer elastomer, enhance the interfacial bonding force between the raw materials in the core layer component, and reduce stress concentration caused by phase separation.

[0024] In step S3 of the present invention, the molten skin component and the core component are respectively extruded by an extruder and ejected through a double-layer concentric spinneret to form concentric fiber filaments composed of the core component and the skin component from the inside out. The mass ratio of the skin component to the core component in the concentric fiber filaments is 1: (2~3), preferably 1: 2.5. The concentric fiber filaments form a gradually decreasing melting temperature gradient and rigidity gradient from the inside out. During the stretching of the concentric fiber filaments in step S4, the thickness of the skin component becomes thinner, and the core component has a high rigidity. The phase change microcapsules in the cortex component will be squeezed by the core layer component during the thinning process and migrate to the surface of the cortex component, so that there are no phase change microcapsules in the center of the phase change fiber after stretching. All phase change microcapsules are concentrated on the outer surface of the phase change fiber, so that the phase change microcapsules are embedded in the outer surface of the phase change fiber. During the use of the cool non-woven fabric, the human body can directly contact the phase change microcapsules, which is beneficial to improve the heat transfer efficiency, thereby improving the thermal management effect of the cool non-woven fabric.

[0025] In step S4 of the present invention, the concentric fiber filaments are stretched 2 to 3 times to form phase change fiber filaments. The stretching process includes three stretching steps, wherein the temperature of the first stretching step is 90 to 100°C and the stretching ratio is 1.2 to 1.3 times, the temperature of the second stretching step is 95 to 105°C and the cumulative stretching ratio is 1.5 to 2 times, and the temperature of the third stretching step is 100 to 110°C and the cumulative stretching ratio is 2 to 3 times; during the stretching process of the concentric fiber filaments, the heating temperature and the stretching ratio are gradually increased through the three stretching steps. When the heating temperature is low, the concentric fiber filaments are still in the initial softening stage. At this time, the low stretching ratio causes the concentric fiber filaments to mainly undergo elastic deformation, avoiding premature plastic deformation and fiber breakage. As the heating temperature increases, the fluidity of the components in the concentric fiber filaments increases and the stretching ratio is gradually increased, thereby improving the stability of the concentric fiber filament stretching process.

[0026] It should be further explained that in the process of forming phase change fibers from concentric fibers through three-stage stretching, the molecular chains in each component of the concentric fibers are gradually rearranged during the heating process, reducing the stress concentration caused by sudden changes in temperature or rate, and reducing the risk of fiber breakage. Ultimately, the concentric fibers can be stably processed into phase change fibers, and the phase change fibers are cut, opened, and combed in step S5 and then laid into a fiber web. After the fiber web is reinforced and formed, a cool non-woven fabric with a gram weight of 20~100gsm is obtained.

[0027] To sum up, the phase change fiber filaments of the present invention are composed of a core layer component and a cortex component from the inside to the outside. The phase change fiber filaments form a melting temperature gradient and a stiffness gradient from the inside to the outside. During the stretching process of the phase change fiber filaments, the phase change microcapsules tend to migrate to the surface area with low shear resistance due to the weak interface bonding with the resin matrix in the cortex component. At the same time, during the thinning process of the cortex component, the phase change microcapsules will be squeezed by the core layer component and further migrate to the surface of the cortex component, so that the phase change microcapsules are concentrated and embedded in the outer surface of the phase change fiber filaments. During the use of the cool non-woven fabric made of phase change fiber filaments, the human body can directly contact the phase change microcapsules, which is beneficial to improve the heat transfer efficiency, thereby improving the thermal management effect of the cool non-woven fabric.

[0028] The present invention is further described below by way of examples and comparative examples.

[0029] Example 1 S1, mixing phase change microcapsules and silane coupling agent in a mass ratio of 100:1, then putting them into an ethanol solution for ultrasonic treatment for 30 minutes to obtain surface-treated phase change microcapsules, and uniformly mixing the surface-treated phase change microcapsules with polyethylene resin, nano-calcium carbonate, calcium stearate, and magnesium stearate to obtain a cortex component, and adding the cortex component into a twin-screw extruder for blending and granulation to obtain cortex particles; The cortex component includes the following components by mass percentage: linear low-density polyethylene 54%, low-density polyethylene 20%, phase change microcapsules 20%, calcium carbonate 4.5%, calcium stearate 1%, and magnesium stearate 0.5%; S2, uniformly mixing polypropylene resin, polyethylene / 1-hexene copolymer elastomer, and styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride to obtain a core layer component, adding the core layer component into a twin-screw extruder for blending and granulation to obtain core layer particles; The core layer components include the following components by mass percentage: 93% polypropylene resin, 5% polyethylene / 1-hexene copolymer elastomer, and 2% styrene-ethylene-butylene-styrene copolymer grafted maleic anhydride; S3, extruding the skin layer particles and the core layer particles through two extruders respectively and spraying them through a double-layer concentric spinneret to form concentric fiber filaments; The concentric fibers are composed of core components and cortex components from the inside out, and the mass ratio of the cortex components to the core components in the concentric fibers is 1:2.5. S4. After extrusion, the concentric fiber filaments are kept warm in an environment at 95° C. and stretched simultaneously. The stretching process includes three stretching steps, wherein the temperature of the first stretching step is 90° C. and the stretching ratio is 1.2 times, the temperature of the second stretching step is 95° C. and the cumulative stretching ratio is 1.5 times, and the temperature of the third stretching step is 100° C. and the cumulative stretching ratio is 2 times. The stretched concentric fiber filaments are cooled and shaped to obtain phase change fiber filaments; S5. The phase change fiber yarns are cut, opened, and combed, and then laid into a fiber web. The fiber web is reinforced and formed by hot air to obtain a cool non-woven fabric.

[0030] Example 2 S1, mixing phase change microcapsules and silane coupling agent in a mass ratio of 100:1, then putting them into an ethanol solution for ultrasonic treatment for 30 minutes to obtain surface-treated phase change microcapsules, and uniformly mixing the surface-treated phase change microcapsules with polyethylene resin, nano-calcium carbonate, calcium stearate, and magnesium stearate to obtain a cortex component, and adding the cortex component into a twin-screw extruder for blending and granulation to obtain cortex particles; The cortex component includes the following components by mass percentage: linear low-density polyethylene 54%, low-density polyethylene 20%, phase change microcapsules 20%, calcium carbonate 4.5%, calcium stearate 1%, and magnesium stearate 0.5%; S2, uniformly mixing polypropylene resin, polyethylene / 1-hexene copolymer elastomer, and styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride to obtain a core layer component, adding the core layer component into a twin-screw extruder for blending and granulation to obtain core layer particles; The core layer components include the following components by mass percentage: 91.5% polypropylene resin, 6.5% polyethylene / 1-hexene copolymer elastomer, and 2% styrene-ethylene-butylene-styrene copolymer grafted maleic anhydride; S3, extruding the skin layer particles and the core layer particles through two extruders respectively and spraying them through a double-layer concentric spinneret to form concentric fiber filaments; The concentric fibers are composed of core components and cortex components from the inside out, and the mass ratio of the cortex components to the core components in the concentric fibers is 1:2.5. S4, after extrusion, the concentric fiber filaments are kept warm in an environment of 95° C. and stretched simultaneously. The stretching process includes three stretching steps, wherein the temperature of the first stretching step is 93° C. and the stretching ratio is 1.25 times, the temperature of the second stretching step is 99° C. and the cumulative stretching ratio is 1.75 times, and the temperature of the third stretching step is 105° C. and the cumulative stretching ratio is 2.5 times. The stretched concentric fiber filaments are cooled and shaped to obtain phase change fiber filaments; S5. The phase change fiber yarns are cut, opened, and combed, and then laid into a fiber web. The fiber web is reinforced and formed by hot air to obtain a cool non-woven fabric.

[0031] Example 3 S1, mixing phase change microcapsules and silane coupling agent in a mass ratio of 100:1, then putting them into an ethanol solution for ultrasonic treatment for 30 minutes to obtain surface-treated phase change microcapsules, and uniformly mixing the surface-treated phase change microcapsules with polyethylene resin, nano-calcium carbonate, calcium stearate, and magnesium stearate to obtain a cortex component, and adding the cortex component into a twin-screw extruder for blending and granulation to obtain cortex particles; The cortex component includes the following components by mass percentage: linear low-density polyethylene 54%, low-density polyethylene 20%, phase change microcapsules 20%, calcium carbonate 4.5%, calcium stearate 1%, and magnesium stearate 0.5%; S2, uniformly mixing polypropylene resin, polyethylene / 1-hexene copolymer elastomer, and styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride to obtain a core layer component, adding the core layer component into a twin-screw extruder for blending and granulation to obtain core layer particles; The core layer components include the following components by mass percentage: 90% polypropylene resin, 8% polyethylene / 1-hexene copolymer elastomer, and 2% styrene-ethylene-butylene-styrene copolymer grafted maleic anhydride; S3, extruding the skin layer particles and the core layer particles through two extruders respectively and spraying them through a double-layer concentric spinneret to form concentric fiber filaments; The concentric fibers are composed of core components and cortex components from the inside out, and the mass ratio of the cortex components to the core components in the concentric fibers is 1:2.5. S4. After extrusion, the concentric fiber filaments are kept warm in an environment at 95° C. and stretched simultaneously. The stretching process includes three stretching steps, wherein the temperature of the first stretching step is 95° C. and the stretching ratio is 1.3 times, the temperature of the second stretching step is 102° C. and the cumulative stretching ratio is 2 times, and the temperature of the third stretching step is 110° C. and the cumulative stretching ratio is 3 times. The stretched concentric fiber filaments are cooled and shaped to obtain phase change fiber filaments; S5. The phase change fiber yarns are cut, opened, and combed, and then laid into a fiber web. The fiber web is reinforced and formed by hot air to obtain a cool non-woven fabric.

[0032] Comparative Example 1 S1, mixing phase change microcapsules and silane coupling agent in a mass ratio of 100:1, then putting them into an ethanol solution for ultrasonic treatment for 30 minutes to obtain surface-treated phase change microcapsules, and uniformly mixing the surface-treated phase change microcapsules with polyethylene resin, nano-calcium carbonate, calcium stearate, and magnesium stearate to obtain a cortex component, and adding the cortex component into a twin-screw extruder for blending and granulation to obtain cortex particles; The cortex component includes the following components by mass percentage: linear low-density polyethylene 54%, low-density polyethylene 20%, phase change microcapsules 20%, calcium carbonate 4.5%, calcium stearate 1%, and magnesium stearate 0.5%; S2, uniformly mixing polypropylene resin, polyethylene / 1-hexene copolymer elastomer, and styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride to obtain a core layer component, adding the core layer component into a twin-screw extruder for blending and granulation to obtain core layer particles; The core layer components include the following components by mass percentage: 93% polypropylene resin, 5% polyethylene / 1-hexene copolymer elastomer, and 2% styrene-ethylene-butylene-styrene copolymer grafted maleic anhydride; S3, extruding the skin layer particles and the core layer particles through two extruders respectively and spraying them through a double-layer concentric spinneret to form concentric fiber filaments; The concentric fibers are composed of core components and cortex components from the inside out, and the mass ratio of the cortex components to the core components in the concentric fibers is 1:2.5. S4. The concentric fibers are cut, opened, and combed, and then laid into a fiber web, which is then reinforced with hot air to form a cool non-woven fabric.

[0033] Comparative Example 2 S1, mixing phase change microcapsules and silane coupling agent at a mass ratio of 100:1, and then placing them in an ethanol solution for ultrasonic treatment for 30 minutes to obtain surface-treated phase change microcapsules; S2, mixing the surface-treated phase change microcapsules with polyethylene resin, nano-calcium carbonate, calcium stearate, and magnesium stearate to obtain a cortex component, adding the cortex component into a twin-screw extruder for blending and granulation to obtain cortex particles; The cortex component includes the following components by mass percentage: linear low-density polyethylene 63%, low-density polyethylene 25%, phase change microcapsules 6.5%, calcium carbonate 4%, calcium stearate 1%, and magnesium stearate 0.5%; S3, uniformly mixing the surface-treated phase change microcapsules with polypropylene resin, polyethylene / 1-hexene copolymer elastomer, and styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride to obtain a core layer component, adding the core layer component into a twin-screw extruder for blending and granulation to obtain core layer particles; The core layer components include the following components by mass percentage: 83.75% polypropylene resin, 7.5% polyethylene / 1-hexene copolymer elastomer, 2% styrene-ethylene-butylene-styrene copolymer grafted maleic anhydride, and 6.75% phase change microcapsules; S4, extruding the skin layer particles and the core layer particles through two extruders respectively and spraying them through a double-layer concentric spinneret to form concentric fiber filaments; The concentric fibers are composed of core components and cortex components from the inside out, and the mass ratio of the cortex components to the core components in the concentric fibers is 1:2.5. S5. After extrusion, the concentric fiber filaments are kept warm in an environment at 95° C. and stretched simultaneously. The stretching process includes three stretching steps, wherein the temperature of the first stretching step is 95° C. and the stretching ratio is 1.3 times, the temperature of the second stretching step is 102° C. and the cumulative stretching ratio is 2 times, and the temperature of the third stretching step is 110° C. and the cumulative stretching ratio is 3 times. The stretched concentric fiber filaments are cooled and shaped to obtain phase change fiber filaments; S6. The phase change fiber yarns are cut, opened, and combed, and then laid into a fiber web. The fiber web is reinforced and formed by hot air to obtain a cool non-woven fabric.

[0034] It should be noted that all the above embodiments and comparative examples use the same phase change microcapsules, which are composed of polyurethane resin wrapped with a phase change material with an internal phase change temperature of 28°C, and all the cooling non-woven fabrics have a gram weight of 50gsm.

[0035] The following test was performed on the cool non-woven fabrics obtained in all the above embodiments and comparative examples: in a room temperature environment, the detection end of a thermocouple was inserted into the inside of the cool non-woven fabric. After the thermocouple reading stabilized, a 50mm×50mm×5mm aluminum sheet was heated to a constant temperature of 36.5°C and then covered on the surface of the cool non-woven fabric. The time required for the aluminum sheet to cover the surface of the cool non-woven fabric until the detection temperature of the thermocouple was greater than 28°C was recorded; the data recorded in the above test are shown in Table 1 below.

[0036]

[0037] Table 1 It can be seen from the data in Table 1 that the content of phase change microcapsules in the cool non-woven fabrics of Example 1, Example 2, and Example 3 is the same. Since the stretching ratio of the phase change fiber filaments in these three embodiments gradually increases, and the thickness of the cortical component decreases with the increase of the stretching ratio, the greater the stretching ratio, the more phase change microcapsules migrate to the surface of the phase change fiber filaments. Since the thermocouple can only measure the surface temperature of the phase change fiber filaments inside the cool non-woven fabric, the more phase change microcapsules on the surface of the phase change fiber filaments, the longer the cool non-woven fabric maintains 28°C.

[0038] In addition, Comparative Example 1 is based on Example 1, and the concentric fiber filaments are directly made into a cool non-woven fabric. Although the phase change microcapsules can still migrate to the surface of the concentric fiber filaments after surface treatment, the number of phase change microcapsules migrating to the surface of the concentric fiber filaments is not as good as that of the stretched phase change fiber filaments. Once the phase change microcapsules on the outermost surface of the cortex component absorb heat to saturation, the surface temperature of the phase change fiber will increase. Therefore, the cool non-woven fabric in Comparative Example 1 maintains 28°C for a shorter time; in Comparative Example 2, the stretching ratio of the phase change fiber filaments and the total addition amount of phase change microcapsules are closest to Example 3. Comparative Example 2 simulates the uniform distribution of phase change microcapsules in the phase change fiber filaments. Although the surface-treated phase change microcapsules can still migrate to the surface, the phase change microcapsules in the core layer component are difficult to break through the core layer component and migrate to the cortex component, resulting in some phase change microcapsules being wrapped in the core layer component. Therefore, the cool non-woven fabric in Comparative Example 2 maintains 28°C for a shorter time.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for producing a cooling nonwoven fabric with embedded phase change capsules, characterized in that: The following steps are involved: S1. Mixing polyethylene resin, phase change microcapsules, calcium carbonate, and stearate to obtain a cortex component, adding the cortex component to a twin-screw extruder for blending and granulation to obtain cortex particles; S2, mixing polypropylene resin and core layer additives to obtain core layer components, adding the core layer components into a twin-screw extruder for blending and granulation to obtain core layer particles; S3, extruding the skin layer particles and the core layer particles through two extruders respectively and spraying them through a double-layer concentric spinneret to form concentric fiber filaments; Among them, the concentric fiber filaments are composed of core components and cortex components from the inside to the outside; S4. After the concentric fibers are extruded, they are kept warm in an environment of 90-110°C and heated for stretching. During the stretching process, the skin component becomes thinner and the internal phase change microcapsules are squeezed by the core component and migrate to the surface of the skin component. The stretched concentric fibers are cooled and shaped to obtain phase change fibers. S5. The phase change fiber yarns are cut, opened, and combed, and then laid into a fiber web, and the fiber web is reinforced and formed to obtain a cool non-woven fabric.

2. The method for producing the cooling nonwoven fabric with embedded phase change capsules according to claim 1, characterized in that: In step S1, the phase change microcapsules need to be surface treated to reduce the surface energy before being mixed with the polyethylene resin. The specific operation is as follows: the phase change microcapsules and the silane coupling agent are mixed in a mass ratio of 100: (0.5~2), and then put into an ethanol solution for ultrasonic treatment for 20~40 minutes, and then filtered and the solid product is dried to obtain the surface-treated phase change microcapsules.

3. The method for producing the cooling nonwoven fabric with embedded phase change capsules according to claim 1, characterized in that: The structure of the phase change microcapsule consists of a capsule shell on the surface wrapping an internal phase change material, the capsule shell is selected from one of polyurethane resin and melamine resin, and the phase change temperature of the phase change material is 20-30°C.

4. The method for producing the cooling nonwoven fabric with embedded phase change capsules according to claim 1, characterized in that: The polyethylene resin includes linear low-density polyethylene and low-density polyethylene, and the skin component includes the following components by mass percentage: linear low-density polyethylene 45% to 65%, low-density polyethylene 15% to 25%, phase change microcapsules 15% to 25%, calcium carbonate 3% to 5%, and stearate 1% to 2%.

5. The method for producing the cooling nonwoven fabric with embedded phase change capsules according to claim 1, characterized in that: The stearate is selected from one or more of calcium stearate, magnesium stearate and zinc stearate.

6. The method for producing the cooling nonwoven fabric with embedded phase change capsules according to claim 1, characterized in that: The core layer additive includes polyethylene / 1-hexene copolymer elastomer and styrene-ethylene-butylene-styrene copolymer grafted with maleic anhydride; The core layer components include the following components by mass percentage: 89% to 94% of polypropylene resin, 5% to 8% of polyethylene / 1-hexene copolymer elastomer, and 1% to 3% of styrene-ethylene-butylene-styrene copolymer grafted maleic anhydride.

7. The method for producing a cooling nonwoven fabric with embedded phase change capsules according to claim 1, characterized in that: The mass ratio of the cortex component to the core component in the concentric fiber yarn is 1:(2-3).

8. The method for producing a cooling nonwoven fabric with embedded phase-change capsules according to claim 1, characterized in that: In step S4, the concentric fiber filaments are stretched 2 to 3 times to form phase change fiber filaments. The stretching process includes three stretching steps, wherein the temperature of the first stretching step is 90 to 100°C and the stretching ratio is 1.2 to 1.3 times, the temperature of the second stretching step is 95 to 105°C and the cumulative stretching ratio is 1.5 to 2 times, and the temperature of the third stretching step is 100 to 110°C and the cumulative stretching ratio is 2 to 3 times.

9. The method for producing a cooling nonwoven fabric with embedded phase-change capsules according to claim 1, characterized in that: The cool non-woven fabric has a gram weight of 20 to 100 gsm.

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