Polyamide elastomer composite fiber as well as preparation method and application thereof

Abstract

The invention relates to the technical field of phase change materials, in particular to a polyamide elastomer composite fiber and a preparation method and application thereof. The preparation method of the polyamide elastomer composite fiber provided by the invention comprises the following steps: (1) taking a polyamide elastomer as a shell material and a solid-liquid phase change material as a core material, and carrying out coaxial melt spinning and curing to obtain a composite fiber precursor; and (2) sequentially carrying out surface crosslinking, drafting and heat setting on the composite fiber precursor to obtain the polyamide elastomer composite fiber. The polyamide elastomer composite fiber obtained by the preparation method has relatively high phase change enthalpy, relatively high energy storage density and relatively high tensile property, and can be used in temperature-adjusting textiles.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change materials, and in particular to a polyamide elastomer composite fiber and a preparation method and application thereof. Background Art

[0002] In the field of polymer materials, polyamide elastomers are a type of thermoplastic elastomer formed by block copolymerization of polyamide hard segments and polyether soft segments. The hard segment in its molecular chain provides excellent mechanical strength, wear resistance and chemical resistance, while the soft segment gives the material high elasticity, flexibility and low-temperature performance. This unique microphase separation structure enables it to have both the elasticity of traditional rubber and the easy processing of thermoplastics. It is widely used in high-end sporting goods, foam materials, smart wearable devices, medical device catheters, and industrial hoses. However, its value is far more than just structural materials. In recent years, researchers are actively exploring its potential as a phase change functional material, especially in the field of intelligent thermal management, which has brought it a new dimension of development.

[0003] Due to the thermodynamic incompatibility between the polyamide hard segments and polyether soft segments in polyamide elastomers, they grow into ordered structures at the submicron scale, resulting in a unique microphase-separated structure. This unique structure allows the hard and soft segments to exhibit independent crystallization and melting temperatures, making polyamide elastomers suitable for phase change materials. Specifically, the crystallizable polyether soft segments undergo a crystallization / melting transition at relatively low temperatures, enabling energy storage and release. The higher-melting-point polyamide hard segments, on the other hand, form physical crosslinks through hydrogen bonding, maintaining the material's macroscopic shape and providing sufficient mechanical strength during the phase transition. Importantly, compared to solid-gas, liquid-gas, and solid-liquid phase change materials, polyamide elastomers, as solid-solid phase change materials, remain in a solid state throughout the phase transition, utilizing only the soft segment's crystal structure transition to absorb and release latent heat. These materials exhibit significant advantages, including minimal volume change, no leakage, non-toxicity, and long-term stability. They demonstrate excellent development potential and application prospects in areas such as personal thermal management systems, thermal management of microelectronic devices, and advanced energy applications. However, low phase transition enthalpy is an inherent disadvantage of solid-solid phase change materials such as polyamide elastomers. This low phase transition enthalpy results in lower energy storage density, which means that more polyamide elastomer mass is required to achieve the same energy storage or temperature regulation effect. This is a serious disadvantage in weight- and space-sensitive applications such as personal thermal management systems and thermal management of microelectronic devices. Improvements to polyamide elastomers to increase their phase transition enthalpy are urgently needed. Summary of the Invention

[0004] The present invention provides a polyamide elastomer composite fiber, a preparation method and application thereof. The polyamide elastomer composite fiber provided by the present invention has a high phase change enthalpy and a high energy storage density, as well as high tensile properties, and can be used in thermal management products, especially temperature-regulating textiles.

[0005] In one aspect, the present invention provides a method for preparing a polyamide elastomer composite fiber, comprising the following steps:

[0006] (1) coaxially melt spinning and solidifying a polyamide elastomer as a shell material and a solid-liquid phase change material as a core material to obtain a composite fiber precursor.

[0007] (2) The composite fiber precursor is subjected to surface crosslinking, stretching and heat setting in sequence to obtain a polyamide elastomer composite fiber.

[0008] Optionally, the melting temperature range of the soft segment in the polyamide elastomer is 5-30° C., and the melting enthalpy of the soft segment is 20-50 J / g.

[0009] Optionally, the polyamide elastomer is prepared by the following steps:

[0010] A. mixing a long carbon chain dibasic acid, a long carbon chain diamine, a polyether diol, water and a first catalyst to carry out an amidation reaction to obtain an amidation reaction liquid,

[0011] B. Mixing the amidation reaction liquid with a second catalyst to carry out polyesterification reaction to obtain a polyamide elastomer.

[0012] Optionally, the long-chain dicarboxylic acid is at least one of sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid and tetradecanedioic acid; the long-chain diamine is at least one of decanediamine, undecanediamine, dodecanediamine, tridecanediamine and tetradecanediamine; the polyether diol is at least one of polyethylene glycol and polytetramethylene glycol, and the molecular weight of the polyether diol is 1000-4000 g / mol; the molar ratio of the long-chain dicarboxylic acid to the long-chain diamine is 2:0.8-1.2, and the molar ratio of the long-chain dicarboxylic acid to the polyether diol is 2:0.8-1.2.

[0013] Optionally, the amount of water used is 20-40% of the total mass of the long-chain dibasic acid, long-chain diamine and polyether diol.

[0014] Optionally, the first catalyst includes at least one of sodium hypophosphite, antimony trioxide, ethylene glycol antimony and germanium oxide, and the added amount of the first catalyst is 1-2‰ of the total mass of the long carbon chain dibasic acid, long carbon chain diamine and polyether diol.

[0015] Optionally, the second catalyst comprises at least one of tetrabutyl titanate, tetrabutyl zirconate and isopropyl titanate, and the second catalyst is added in an amount of 2-4 ‰ of the total mass of the long-chain dibasic acid, long-chain dibasic amine and polyether glycol.

[0016] Optionally, the amidation reaction is carried out in a closed inert gas atmosphere, the reaction temperature is 150-180℃, and the reaction time is 1.8-2.2h.

[0017] Optionally, the polyesterification reaction is carried out under vacuum conditions, the reaction temperature is 240-260℃, and the reaction time is 3-5h.

[0018] Optionally, the solid-liquid phase change material is at least one of polyethylene glycol, polytetrahydrofuran ether glycol and polyethylene glycol dimethyl ether, and the molecular weight is 6000-10000g / mol.

[0019] Optionally, the coaxial melt spinning is carried out in a bi-component melt spinning machine with double extrusion channels, wherein the 1-zone-4-zone screw temperatures of the polyamide elastomer in the bi-component melt spinning machine are 168-172℃, 173-177℃, 178-182℃ and 183-187℃ in sequence, the 1-zone-4-zone screw temperatures of the phase change material in the bi-component melt spinning machine are 58-62℃, 68-72℃, 73-77℃ and 78-82℃ in sequence, and the temperature of the spinneret is 175-185℃.

[0020] Optionally, the inner hole diameter of the inner hole of the spinning hole of the coaxial spinning is 0.1-0.15mm, the outer hole diameter of the inner hole is 0.11-0.16mm, the inner hole diameter of the outer hole is 0.16-0.20mm, and the outer hole diameter of the outer hole is 0.17-0.21mm.

[0021] Optionally, the solidification is cooling solidification, and the temperature of the side-blowing cooling air during the cooling solidification is 10-15℃, and the wind speed is 0.4-0.6m / s.

[0022] Optionally, the surface crosslinking is carried out by spraying a diisocyanate solution to the composite fiber precursor, wherein the diisocyanate in the diisocyanate solution is at least one of hexamethylene diisocyanate, diphenyl methane diisocyanate and isophorone diisocyanate, the concentration of the diisocyanate solution is 5-10wt%, and the solvent of the diisocyanate solution is ethyl acetate.

[0023] Optionally, the temperature of the drawing is 60-70℃, and the drawing ratio is 2.0-4.0.

[0024] Optionally, the temperature of the heat setting is 100-120℃, and the time is 3-5min.

[0025] On the other hand, the present invention also provides a polyamide elastomer composite fiber, which is prepared by the preparation method described in any one of the above technical solutions.

[0026] On the other hand, the present invention also provides the use of the polyamide elastomer composite fiber described in the above technical solution in thermal management products.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The polyamide elastomer composite fiber obtained by the preparation method provided by the present invention has a polyamide elastomer as a shell and a phase change material as a core, thereby constructing a core-shell structure phase change material with synergistic heat storage. The present invention utilizes the characteristics of the polyamide elastomer itself as a solid-solid phase change material. The soft segment crystal transformation can contribute a part of the latent heat and maintain good thermal responsiveness, while the physical cross-linking points composed of the hard segment hydrogen bond network provide a stable three-dimensional skeleton during the entire phase change process, thereby ensuring the integrity of the fiber's macroscopic shape and excellent mechanical strength, and fundamentally eliminating the leakage problem. At the same time, the solid-liquid phase change material encapsulated in the core provides an extremely high phase change latent heat through its inherent solid-liquid phase change, greatly improving the overall energy density of the composite fiber, and successfully making up for the inherent defect of the low enthalpy value of a single solid-solid phase change material. The composite fiber finally obtained cleverly combines the advantages of both solid-solid phase change and solid-liquid phase change, and is an ideal thermal management material with high enthalpy value, absolute leakage-free, high strength and high toughness.

[0029] Furthermore, through surface cross-linking, a cross-linked network structure is formed on the surface of the composite fiber, eliminating possible microscopic defects, further preventing leakage of the core phase change material, and improving the stability of the composite fiber.

[0030] In addition, the polyamide elastomer composite fiber obtained by the preparation method provided by the present invention has excellent temperature management capabilities and can be used in thermal management products, especially temperature-regulating textiles, opening up its application development direction in new high-value-added scenarios such as personal thermal management systems and microelectronic device thermal management systems, showing extremely excellent development prospects and application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other objects, features and advantages of the present invention will be apparent from the following description of preferred embodiments illustrating the subject matter of the present invention and its use and the accompanying drawings, in which:

[0032] Figure 1 These are transmission electron micrographs of the polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer obtained in Comparative Example 1, wherein (a) is the polyamide elastomer composite fiber obtained in Example 1, and (b) is the polyamide elastomer obtained in Comparative Example 1.

[0033] Figure 2 The temperature change curves of the polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer fiber obtained in Comparative Example 1 after being transferred from a cold environment to a hot environment and from a hot environment to a cold environment, wherein (a) is the temperature change curve of the polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer fiber obtained in Comparative Example 1 after being transferred from a room at about 20°C to a hot outdoor environment in summer, and (b) is the temperature change curve of the polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer fiber obtained in Comparative Example 1 after being transferred from a room at about 25°C to a cold outdoor environment in winter. DETAILED DESCRIPTION

[0034] Below by specific embodiment, the present invention is described, those skilled in the art will appreciate that, below specific embodiment is only for illustrative purpose, and does not limit the scope of the present invention in any way.In addition, in the following embodiments, unless otherwise stated, employed reagent and equipment are all commercially available.If in the embodiment below, concrete treatment condition and treatment process are not clearly described, then can adopt condition and method well known in the art to process.

[0035] The present invention provides a method for preparing a polyamide elastomer composite fiber, comprising the following steps:

[0036] (1) coaxially melt spinning and solidifying a polyamide elastomer as a shell material and a solid-liquid phase change material as a core material to obtain a composite fiber precursor.

[0037] (2) The composite fiber precursor is subjected to surface crosslinking, stretching and heat setting in sequence to obtain a polyamide elastomer composite fiber.

[0038] The present invention constructs a core-shell structure with synergistic heat storage through the above method. The polyamide elastomer of the shell layer, by virtue of its own characteristics as a solid-solid phase change material, can not only utilize the crystal form of the soft segment to contribute a part of the latent heat to the composite fiber, but also utilize the physical cross-linking points composed of the hydrogen bond network of the hard segment to ensure the integrity of the macroscopic shape and excellent mechanical strength of the composite fiber during the phase change process, fundamentally eliminating the leakage problem. At the same time, the solid-liquid phase change material as the core layer provides extremely high phase change latent heat through its inherent solid-liquid phase change, greatly improving the overall energy density of the composite fiber, and successfully making up for the inherent defect of low enthalpy value of a single solid-solid phase change material. The polyamide elastic composite fiber finally obtained cleverly combines the advantages of both solid-solid phase change and solid-liquid phase change, and is an ideal thermal management material with high enthalpy value, no leakage, high strength and high toughness.

[0039] The present invention firstly uses a polyamide elastomer as a shell material and a solid-liquid phase change material as a core material to perform coaxial melt spinning and solidification to obtain a composite fiber precursor.

[0040] In some embodiments of the present invention, the melting temperature range of the soft segment in the polyamide elastomer is 5-30°C, specifically 5.1°C, 22.6°C, etc.; the melting enthalpy of the soft segment is 20-50 J / g, specifically 18.4 J / g, 46.4 J / g, etc.

[0041] In some embodiments of the present invention, the polyamide elastomer is prepared by the following steps:

[0042] A. mixing a long carbon chain dibasic acid, a long carbon chain diamine, a polyether diol, water and a first catalyst to carry out an amidation reaction to obtain an amidation reaction liquid,

[0043] B. Mixing the amidation reaction liquid with a second catalyst to carry out polyesterification reaction to obtain a polyamide elastomer.

[0044] In some embodiments of the present invention, the one-pot method for preparing a solid-solid phase change material (PSCM) polyamide elastomer is used as the shell material. This method is simple, efficient, and amenable to industrial production. Compared to the heterogeneous reaction of the polyamide hard segment and the polyether soft segment in the traditional two-step method, this reaction system exhibits good raw material compatibility and can be considered a homogeneous reaction, resulting in a higher reaction rate.

[0045] In the present invention, the term "long carbon chain" refers to a carbon chain with a carbon chain length of ten carbon atoms or more, such as the carbon chain length of sebacic acid is ten carbon atoms.

[0046] In some embodiments of the present invention, the long carbon chain dibasic acid is at least one of sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid and tetradecanedioic acid; the long carbon chain diamine is at least one of decanediamine, undecanediamine, dodecanediamine, tridecanediamine and tetradecanediamine; the polyether diol is at least one of polyethylene glycol and polytetramethylene glycol, and the molecular weight of the polyether diol is 1000-4000 g / mol, specifically 1000 g / mol, 3000 g / mol, 4000 g / mol, etc. The molecular weight of the polyether diol is 1000-4000 g / mol. -4000g / mol, which can ensure that the obtained polyamide elastomer has both good comprehensive mechanical properties (tensile strength and ductility) and a high enthalpy value. If the molecular weight is too low, although the material strength is high, the ductility is poor and the enthalpy value is low. If the molecular weight is too high, the strength of the material will decrease significantly, resulting in a poor protective effect when used as a shell. The molar ratio of the long-chain dibasic acid to the long-chain diamine is 2:0.8-1.2, specifically 2:0.8, 2:1, 2:1.2, etc. The molar ratio of the long-chain dibasic acid to the polyether diol is 2:0.8-1.2, specifically 2:0.8, 2:1, 2:1.2, etc. In the present invention, the polyether diol is the soft segment of the polyamide elastomer. The polyether diol of the aforementioned molecular weight not only ensures good reactivity but also imparts excellent physical and mechanical properties and phase transition properties to the resulting elastomer. The use of long-chain dibasic acids and long-chain diamines (i.e., the hard segment is a long-chain polyamide) in the present invention facilitates the production of a long-chain polyamide elastomer material with both excellent flexibility and mechanical properties. The aforementioned ratio ensures that the polyamide hard segment in the resulting elastomer has a relatively moderate molecular chain length, thereby simultaneously exhibiting good mechanical strength and ductility. If the ratio is too large, the hard segment molecular chain length is excessively long, resulting in high material strength but low ductility and a low phase transition enthalpy. Conversely, a lower ratio results in low material strength and poor long-term durability.

[0047] In some embodiments of the present invention, the first catalyst includes at least one of sodium hypophosphite, antimony trioxide, ethylene glycol antimony and germanium oxide, and the amount of the first catalyst added is 1-2‰ of the total mass of the long carbon chain dibasic acid, long carbon chain diamine and polyether diol, for example, 1‰, 1.5‰, 2‰, etc.

[0048] In some embodiments of the present invention, the amount of water used is 20-40% of the total mass of the long-chain dibasic acid, long-chain diamine and polyether diol, specifically 20%, 30%, 40%, etc.; the water can be conventional experimental water such as deionized water and purified water. In the preparation process of traditional polyamide elastomers, the amount of water added is generally about 10% of the material mass, while the present invention greatly increases the amount of water added. By increasing the amount of water added, on the one hand, the amidation reaction can be promoted, and on the other hand, the polyesterification reaction can be inhibited to accelerate the reaction rate of the amidation reaction.

[0049] In some embodiments of the present invention, the amidation reaction is carried out in a closed inert gas atmosphere, wherein the inert gas atmosphere refers to a chemically inert gas, including nitrogen or an inert gas (such as He, Ar, etc.), and the inert gas atmosphere can avoid the occurrence of side reactions; the reaction temperature of the amidation reaction is 150-180°C, specifically 150°C, 170°C, 180°C, etc.; the duration of the amidation reaction is 1.8-2.2h, specifically 1.8h, 2h, 2.2h. In the preparation process of traditional polyamide elastomers, the reaction temperature of the amidation reaction is generally above 190°C, while in the preparation process of the polyamide elastomer of the present invention, the temperature of the amidation reaction stage is relatively low, which can effectively inhibit the occurrence of the polyesterification reaction at this stage, thereby further accelerating the reaction rate of the amidation reaction and improving production efficiency. The present invention can make the amidation reaction and polyesterification reaction proceed separately by adjusting the water and reaction temperature, thereby obtaining a polyamide elastomer with a relatively regular structure and excellent comprehensive performance.

[0050] The present invention has no particular limitation on the method for obtaining the inert gas atmosphere, and a conventional gas replacement method may be used.

[0051] In some embodiments of the present invention, the second catalyst includes at least one of tetrabutyl titanate, tetrabutyl zirconate and isopropyl titanate, and the amount of the second catalyst added is 2-4‰ of the total mass of the long carbon chain dibasic acid, long carbon chain diamine and polyether diol, specifically 2‰, 3‰, 4‰, etc.

[0052] In some embodiments of the present invention, the polyesterification reaction is carried out under vacuum conditions; the reaction temperature is 240-260°C, specifically 240°C, 250°C, 260°C, etc.; the reaction time is 3-5h, specifically 3h, 4h, 5h, etc.

[0053] The present invention does not specifically limit the method for achieving the vacuum conditions; any vacuum conditions are sufficient. In an embodiment of the present invention, the vacuum conditions are achieved by: after the amidation reaction is completed, the reactor is depressurized and then vacuumed; the vacuum state is maintained during the polyesterification reaction. In the present invention, depressurizing the reactor removes moisture from the amidation reaction solution; and conducting the polyesterification reaction under vacuum conditions ensures that the water generated during the polyesterification reaction is promptly removed, ensuring that the polyesterification reaction proceeds under anhydrous conditions, accelerating the polyesterification reaction, and ultimately directly obtaining the polyamide elastomer as a dry product.

[0054] In some embodiments of the present invention, the solid-liquid phase change material is at least one of polyethylene glycol, polytetramethylene ether glycol, and polyethylene glycol dimethyl ether, and its molecular weight is 6000-10000 g / mol. The phase change enthalpy value of the solid-liquid phase change material with the above molecular weight is relatively high, which can ensure that a large amount of heat energy can be significantly absorbed / stored during the phase change process, thereby giving the final composite fiber a better phase change enthalpy value, that is, excellent phase change performance; if the molecular weight is too low, its enthalpy value is low, and it is difficult to achieve excellent phase change performance of the composite fiber; if the molecular weight is too high, although the enthalpy value is large, the melting temperature will also increase simultaneously, resulting in difficulty in melting within the conventional temperature range (20-40°C), that is, hindering the occurrence of the phase change process.

[0055] In the present invention, when the polyamide elastomer and the solid-liquid phase change material are relatively moist, they can be dried before use, such as by vacuum drying at 80°C for 48 hours; when both the polyamide elastomer and the solid-liquid phase change material are dry products, they can be used directly.

[0056] In some embodiments of the present invention, the coaxial melt spinning is carried out in a two-component melt spinning machine with dual extrusion channels, wherein the screw temperatures of the polyamide elastomer in zones 1 to 4 in the two-component melt spinning machine are 168-172°C, 173-177°C, 178-182°C, and 183-187°C, specifically 170°C, 175°C, 180°C, and 185°C, respectively; the screw temperatures of the phase change material in zones 1 to 4 in the two-component melt spinning machine are 58-62°C, 68-72°C, 73-77°C, and 78-82°C, specifically 60°C, 70°C, 75°C, and 80°C, respectively; and the temperature of the spinneret is 175-185°C, specifically 175°C, 180°C, 185°C, etc. The above screw temperature settings can ensure that the material can achieve good melting and have a certain viscosity, and can smoothly and stably carry out the spinning process.

[0057] In some embodiments of the present application, the inner hole diameter of the coaxial spinning orifice is 0.1-0.15 mm, specifically 0.13 mm; the outer hole diameter of the inner hole is 0.11-0.16 mm, specifically 0.16 mm; the inner hole diameter of the outer hole is 0.16-0.20 mm, specifically 0.18 mm; and the outer hole diameter of the outer hole is 0.17-0.21 mm, specifically 0.21 mm. The above hole diameters can ensure that the polyamide elastomer (shell layer) has a certain thickness, which can prevent the internal phase change material from leaking, while at the same time, the load of the core layer phase change material is as high as possible under the condition of no leakage, so that the obtained composite phase change fiber has very excellent phase change performance.

[0058] In some embodiments of the present application, the solidification is cooling solidification, and the temperature of the side-blowing cooling air during the cooling solidification is 10-15℃, specifically 10℃, 13℃, 15℃, etc.; and the wind speed is 0.4-0.6 m / s, specifically 0.4 m / s, 0.5 m / s, 0.6 m / s, etc. The above temperature and wind speed ensure that the composite fiber precursor is fully solidified, while avoiding fiber breakage.

[0059] After obtaining the composite fiber precursor, the composite fiber precursor is sequentially subjected to surface crosslinking, drawing and heat setting to obtain a polyamide elastomer composite fiber.

[0060] In some embodiments of the present application, the surface crosslinking is performed by spraying a diisocyanate solution onto the composite fiber precursor, wherein the diisocyanate in the diisocyanate solution is at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate, the concentration of the diisocyanate solution is 5-10 wt%, specifically 5 wt%, 8 wt%, 10 wt%, etc.; the solvent of the diisocyanate solution can be any solvent that does not react with diisocyanate and has a boiling point lower than 100℃; in the embodiments of the present application, the solvent of the diisocyanate solution is ethyl acetate. In the present application, the surface crosslinking reaction is fast, and after spraying the diisocyanate solution, the composite fiber precursor can be directly transported to the next reaction section without waiting. During the surface crosslinking process, the diisocyanate reacts with the active groups (hydroxyl and carboxyl groups, etc.) on the surface of the polyamide elastomer as the shell layer to form a crosslinked network structure on the surface of the composite fiber, eliminate possible micro defects, further prevent the leakage of the core layer phase change material, and improve the use stability and mechanical strength of the composite fiber.

[0061] In some embodiments of the present invention, the drawing temperature is 60-70°C, specifically 60°C, 65°C, or 70°C; the draw ratio is 2.0-4.0, specifically 2.0, 3.0, or 4.0. In the present invention, drawing can orient the molecular chains within the fiber, making their arrangement more regular and beneficial for improving mechanical properties. The preferred temperature and draw ratio further ensure good regularity and prevent the molecular chains from breaking.

[0062] In some embodiments of the present invention, the heat setting temperature is 100-120°C, specifically 100°C, 110°C, or 120°C, and the duration is 3-5 minutes. The present invention does not particularly limit the specific heat setting method; any method that meets the above conditions may be employed. For example, heat setting can be achieved by passing the resulting fiber through a hot air flow atmosphere. Heat setting can eliminate internal stress in the fiber, ensuring that the resulting fiber has good mechanical properties.

[0063] The present invention does not particularly limit the storage method of the polyamide elastomer composite fiber obtained after heat setting; conventional fiber storage methods, such as winding, may be used. In some embodiments of the present invention, the polyamide elastomer composite fiber is stored by winding at a speed of 1500-3000 r / min, specifically 1500 r / min, 2000 r / min, 2500 r / min, and 3000 r / min.

[0064] The present invention also provides a polyamide elastomer composite fiber, prepared by the preparation method described in any one of the above technical solutions. In some embodiments of the present invention, the diameter of the polyamide elastomer composite fiber is 0.1-0.4 mm, specifically 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, etc.

[0065] The present invention also provides the use of the polyamide elastomer composite fiber described in the above technical solution in thermal management products (i.e., temperature control products). The polyamide elastomer composite fiber prepared by the present invention has excellent temperature management capabilities and can be used in thermal management products, such as temperature control textiles, opening up its application development direction in new high-value-added scenarios such as personal thermal management systems and thermal management products for microelectronic devices.

[0066] The following will be combined with the accompanying drawings and embodiments to clearly and completely describe the technical solutions of the present invention. The embodiments of this application are only for example, and all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0067] Example 1

[0068] (1) Sebacic acid, decanediamine, polytetramethylene glycol (molecular weight 3000 g / mol), deionized water, and sodium hypophosphite are added to a polymerization reactor, the air in the polymerization reactor is replaced with an inert gas, and then the temperature is raised to 170°C and the reaction is carried out at a constant temperature for 2 hours to obtain an amidation reaction liquid, wherein the molar ratio of sebacic acid, decanediamine and polytetramethylene glycol is 2:1:1, the amount of deionized water is 30% of the total mass of sebacic acid, decanediamine and polytetramethylene glycol, and the amount of sodium hypophosphite is 2‰ of the total mass of sebacic acid, decanediamine and polytetramethylene glycol. Tetrabutyl titanate (2‰ of the total mass of sebacic acid, decanediamine, and polytetramethylene glycol) was added to the amidation reaction solution, and the temperature was raised to 250°C. The polymerization reactor was evacuated and the pressure in the reactor was reduced to below 100 Pa over 0.75 hours. After a 4-hour constant temperature reaction, the reaction was terminated, the reactor was filled with inert gas to return to normal pressure, and the material was discharged to obtain a polyamide elastomer. The melting temperature of the soft segment in the obtained polyamide elastomer was 22.6°C, and the melting enthalpy of the soft segment was 46.4 J / g.

[0069] (2) Polyamide elastomer as a shell material and polytetramethylene ether glycol (molecular weight 8000 g / mol) as a core material are added to a two-component melt spinning machine for coaxial melt spinning and cooling and solidification to obtain a composite fiber precursor, wherein the screw temperatures of polyamide elastomer in zones 1 to 4 in the two-component melt spinning machine are 170°C, 175°C, 180°C and 185°C, respectively; the screw temperatures of polytetramethylene ether glycol in zones 1 to 4 in the two-component melt spinning machine are 60°C, 70°C, 75°C and 80°C, respectively; the temperature of the spinneret is 180°C; the inner diameter of the spinneret hole is 0.13 mm, the outer diameter of the inner hole is 0.16 mm, the inner diameter of the outer hole is 0.18 mm, and the outer diameter of the outer hole is 0.21 mm; the temperature of the side-blown cooling air for cooling and solidification is 10°C, and the wind speed is 0.5 m / s.

[0070] (3) A 5 wt% hexamethylene diisocyanate ethyl acetate solution was sprayed onto the composite fiber precursor for surface cross-linking, and then the composite fiber was stretched at a stretching temperature of 70°C with a stretching ratio of 3.0, and then heat-set at 120°C for 3 minutes to obtain a polyamide elastomer composite fiber with a diameter of 0.2 mm. The polyamide elastomer composite fiber was then wound and stored at a winding speed of 2000 r / min.

[0071] Example 2

[0072] The polyamide elastomer composite fiber was prepared according to the method of Example 1, except that the core material was polytetramethylene ether glycol with a molecular weight of 8000 g / mol.

[0073] Example 3

[0074] A polyamide elastomer composite fiber was prepared according to the method of Example 1, except that the molecular weight of the polytetramethylene ether glycol used in preparing the polyamide elastomer was 1000 g / mol. The melting temperature of the soft segment in the resulting polyamide elastomer was 5.1° C., and the melting enthalpy of the soft segment was 18.4 J / g.

[0075] Example 4

[0076] The polyamide elastomer composite fiber was prepared according to the method of Example 3, except that the core material was polytetramethylene ether glycol with a molecular weight of 4000 g / mol.

[0077] Comparative Example 1

[0078] Polyamide elastomer fibers were prepared according to the method of Example 1, except that both the core material and the shell material were polyamide elastomers.

[0079] Comparative Example 2

[0080] Polyamide elastomer fibers were prepared according to the method of Example 3, except that both the core material and the shell material were polyamide elastomers.

[0081] The structures of the polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer obtained in Comparative Example 1 were characterized using a transmission electron microscope. Figure 1 As shown, (a) is a transmission electron micrograph of the polyamide elastomer composite fiber obtained in Example 1, and (b) is a transmission electron micrograph of the polyamide elastomer obtained in Comparative Example 1. Figure 1 It can be seen that the polyamide elastomer composite fiber obtained in Example 1 is a core-shell structure, while the polyamide elastomer fiber obtained in Comparative Example 1 is a conventional monofilament fiber structure, which fully proves that the preparation method provided by the present invention can successfully prepare the target polyamide elastomer composite fiber.

[0082] The tensile properties (tested using the method in GB / T 14337-2022) and phase change properties (tested using differential scanning calorimetry) of the polyamide elastomer composite fibers obtained in Examples 1-4 and Comparative Examples 1-2 were tested, and the results are shown in Table 1. Comparison between Example 1 and Comparative Example 1, and between Example 2 and Comparative Example 2 shows that the introduction of the core-shell structure can significantly increase the phase change enthalpy (including the crystallization enthalpy (ΔH)) of the polyamide elastomer composite fibers. c ) and melting enthalpy (ΔH m)), the phase change enthalpy in Examples 1-4 all exceeds 100 J / g, which has reached the enthalpy level of traditional solid-liquid phase change materials and is much higher than the phase change enthalpy of simple polyamide elastomer solid-solid phase change materials (such as Comparative Examples 1 and 2). At the same time, the introduction of the core-shell structure does not significantly reduce the mechanical properties of the polyamide elastomer composite fiber, and it still has high strength and good ductility. In addition, it can be seen from the relevant data of Examples 1-4 that the materials of the shell layer and the core layer can be designed to achieve directional regulation of the phase change properties (including phase change temperature and phase change enthalpy), thereby meeting the thermal management performance requirements under specific application conditions.

[0083] Table 1 Tensile properties and phase change properties of the fibers obtained in Examples 1-4 and Comparative Examples 1-2

[0084]

[0085] The polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer fiber obtained in Comparative Example 1 were woven into a fiber fabric, which was transferred from a cold environment to a hot environment or from a hot environment to a cold environment. An infrared thermal imager was used to monitor the surface temperature of the fiber fabric, thereby testing the temperature change curves of the polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer fiber obtained in Comparative Example 1 after transferring from a cold environment to a hot environment and from a hot environment to a cold environment. The results are shown in FIG. Figure 2 As shown, (a) is the temperature change curve of the polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer fiber obtained in Comparative Example 1 after being transferred from a room temperature of about 20°C to a hot outdoor in summer, and (b) is the temperature change curve of the polyamide elastomer composite fiber obtained in Example 1 and the polyamide elastomer fiber obtained in Comparative Example 1 after being transferred from a room temperature of about 25°C to a cold outdoor in winter. Figure 2 From (a) in the figure, we can see that the temperature of the polyamide elastomer fiber (Comparative Example 1) rises rapidly in a short period of time and eventually maintains at about 40-45°C, while the temperature of the polyamide elastomer composite fiber (Example 1) rises more slowly, with an obvious lag period. This is because a large amount of high enthalpy phase change material in its core layer melts (from crystalline to amorphous), absorbing a large amount of heat, so its temperature rises slowly and can be maintained at about 35°C. This shows that the temperature management ability of the polyamide elastomer composite fiber is significantly stronger than that of the polyamide elastomer fiber. Figure 2As can be seen from (b) in the table, the temperature of the polyamide elastomer fiber (Comparative Example 1) rapidly dropped in a short time and was finally maintained at about -10°C, while the temperature of the polyamide elastomer composite fiber (Example 1) dropped more slowly and there was a clear hysteresis period, because a large amount of high-enthalpy phase change material in the core layer of the polyamide elastomer composite fiber crystallized (from amorphous state to crystalline state) and released a large amount of heat, so the temperature dropped slowly and was maintained at about 5°C. This also shows that the temperature management ability of the polyamide elastomer composite fiber is significantly stronger than that of the polyamide elastomer fiber.

[0086] While the preferred embodiments of the application have been illustrated and described, it will be clear to those skilled in the art that various changes can be made without departing from the spirit and scope of the application, which is not to be limited to what is described in the specification.

Claims

1. A method for preparing a polyamide elastomer composite fiber, comprising the following steps: (1) coaxially melt spinning and solidifying a polyamide elastomer as a shell material and a solid-liquid phase change material as a core material to obtain a composite fiber precursor. (2) The composite fiber precursor is subjected to surface crosslinking, stretching and heat setting in sequence to obtain a polyamide elastomer composite fiber.

2. The preparation method according to claim 1, characterized in that The melting temperature range of the soft segment in the polyamide elastomer is 5-30° C., and the melting enthalpy of the soft segment is 20-50 J / g.

3. The preparation method according to claim 2, characterized in that The polyamide elastomer is prepared by the following steps: A. mixing a long carbon chain dibasic acid, a long carbon chain diamine, a polyether diol, water and a first catalyst to carry out an amidation reaction to obtain an amidation reaction liquid, B. Mixing the amidation reaction liquid with a second catalyst to carry out polyesterification reaction to obtain a polyamide elastomer.

4. The preparation method according to claim 3, characterized in that The long carbon chain dibasic acid is at least one of sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid and tetradecanedioic acid; the long carbon chain diamine is at least one of decanediamine, undecanediamine, dodecanediamine, tridecanediamine and tetradecanediamine; the polyether diol is at least one of polyethylene glycol and polytetramethylene glycol, and the molecular weight of the polyether diol is 1000-4000 g / mol; the molar ratio of the long carbon chain dibasic acid to the long carbon chain diamine is 2:0.8-1.2, and the molar ratio of the long chain dibasic acid to the polyether diol is 2:0.8-1.

2. The amount of water used is 20-40% of the total mass of the long carbon chain dibasic acid, long carbon chain diamine and polyether diol. The first catalyst comprises at least one of sodium hypophosphite, antimony trioxide, ethylene glycol antimony and germanium oxide, and the amount of the first catalyst added is 1-2‰ of the total mass of the long carbon chain dibasic acid, long carbon chain diamine and polyether diol. The second catalyst includes at least one of tetrabutyl titanate, tetrabutyl zirconate and isopropyl titanate, and the added amount of the second catalyst is 2-4‰ of the total mass of the long carbon chain dibasic acid, long carbon chain diamine and polyether diol.

5. The preparation method according to claim 3 or 4, characterized in that The amidation reaction is carried out in a closed inert gas atmosphere at a temperature of 150-180° C. for 1.8-2.2 h. The polyesterification reaction is carried out under vacuum conditions, the reaction temperature is 240-260° C., and the reaction time is 3-5 hours.

6. The preparation method according to claim 1, characterized in that The solid-liquid phase change material is at least one of polyethylene glycol, polytetramethylene ether glycol, and polyethylene glycol dimethyl ether, and has a molecular weight of 6000-10000 g / mol.

7. The preparation method according to claim 1, characterized in that The coaxial melt spinning is carried out in a bicomponent melt spinning machine with dual extrusion channels, wherein the screw temperatures of zones 1 to 4 of the polyamide elastomer in the bicomponent melt spinning machine are 168-172° C., 173-177° C., 178-182° C., and 183-187° C., respectively; the screw temperatures of zones 1 to 4 of the phase change material in the bicomponent melt spinning machine are 58-62° C., 68-72° C., 73-77° C., and 78-82° C., respectively; and the temperature of the spinneret is 175-185° C. The inner diameter of the spinneret of the coaxial spinneret is 0.1-0.15 mm, the outer diameter of the inner hole is 0.11-0.16 mm, the inner diameter of the outer hole is 0.16-0.20 mm, and the outer diameter of the outer hole is 0.17-0.21 mm. The solidification is cooling solidification, and the temperature of the side-blown cooling air during the cooling solidification process is 10-15° C. and the wind speed is 0.4-0.6 m / s.

8. The preparation method according to claim 1, characterized in that The surface crosslinking is performed by spraying a diisocyanate solution onto the composite fiber precursor, wherein the diisocyanate in the diisocyanate solution is at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate, the concentration of the diisocyanate solution is 5-10wt%, and the solvent of the diisocyanate solution is ethyl acetate. The drawing temperature is 60-70°C, and the drawing ratio is 2.0-4.0; The heat setting temperature is 100-120° C. and the time is 3-5 minutes.

9. A polyamide elastomer composite fiber prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the polyamide elastomer composite fiber according to claim 9 in thermal management products.

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