A method for preparing phase change temperature regulating polyester fibers by filling hollow fibers with in-situ limited and shaped phase change materials and phase change temperature regulating polyester fibers

Abstract

The application discloses a method for preparing phase change temperature-regulating polyester fibers by filling hollow fibers with in-situ limited phase change materials and the phase change temperature-regulating polyester fibers, and belongs to the technical field of functional textile fibers.The phase change material, acrylate composite monomers and a photoinitiator are compounded into an oil phase, the oil phase is filled into the inner cavity of hollow polyester fibers through vacuum infusion, and the inner cavity is heat-sealed; then, the inner cavity acrylate monomers are in-situ crosslinked and polymerized under the induction of ultraviolet light to generate a three-dimensional polyacrylate network for limiting and shaping the phase change material in space; finally, the finished fibers are obtained through heat drawing and winding.The application solves the defects of traditional hollow filled phase change fibers, such as easy precipitation of phase change medium, unstable mechanical properties and temperature control performance, and permanently locks the phase change material in the three-dimensional network in the inner cavity, and the phase change material does not leak in cold and hot cycles, washing and high-temperature processing; the finished polyester fibers have stable mechanical properties and long-acting intelligent temperature-regulating capacity, and are suitable for various temperature control textiles, such as thermal clothing, special protection and home textiles.

Description

Technical Field

[0001] This invention relates to the field of functional polyester fiber preparation technology, and more specifically to a method for preparing phase change temperature-regulating polyester fibers by filling hollow fibers with in-situ confined and shaped phase change materials, and the phase change temperature-regulating polyester fibers themselves. Background Technology

[0002] Phase change temperature-regulating polyester fibers achieve intelligent temperature control in fabrics by absorbing / releasing heat through phase change materials, and have broad application prospects in thermal clothing, outdoor workwear, home textiles, and special protective textiles. Currently, the mainstream phase change fiber preparation processes fall into two categories:

[0003] 1. Spinning Blending Method: Phase change microcapsules are incorporated into polyester melt or spinning solution for co-spinning. Disadvantages: Microcapsules are easily destroyed by high-temperature melts, resulting in a significant decrease in latent heat of phase change; the amount of microcapsules is limited, leading to weak temperature regulation.

[0004] 2. Hollow Fiber Impregnation and Filling Method: Liquid phase change material is directly poured into the inner cavity of hollow fibers, relying on the physical enclosure of the fiber tube wall. Disadvantages: Relying solely on the physical constraint of the hollow cavity, the phase change material exhibits strong fluidity during the solid-liquid phase change, making it prone to leakage and precipitation from the fiber ends and micropores of the tube wall after heating, stretching, and washing; lacking a stable supporting framework, the flow distribution of the phase change medium within the inner cavity is uneven during fiber stretching, resulting in large fluctuations in the mechanical and temperature-regulating properties of the finished fiber.

[0005] Existing technologies generally suffer from shortcomings such as easy precipitation and leakage of phase change materials, poor fiber performance stability, insufficient temperature control durability, and difficulty in continuous industrial production. There is an urgent need for a new preparation process that can achieve permanent confinement of the internal cavity of phase change materials and take into account both fiber mechanical properties and long-term temperature regulation effect. Summary of the Invention

[0006] In view of this, the present invention addresses the shortcomings of existing phase change temperature-regulating polyester fiber preparation processes, such as easy precipitation and leakage of phase change materials, unstable fiber mechanical and temperature control properties, and inability to achieve high-quality large-scale production. It provides a method for preparing phase change temperature-regulating polyester fibers by filling hollow fibers with in-situ confined and shaped phase change materials. This method permanently confines and locks the phase change material within the fiber cavity through in-situ ultraviolet polymerization of a three-dimensional polyacrylate network, completely solving the problem of phase change medium leakage and precipitation, while simultaneously ensuring fiber stretching and processing performance and long-term stable temperature regulation, thus achieving continuous large-scale preparation of high-quality phase change temperature-regulating polyester fibers.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing phase change temperature-regulating polyester fibers by filling hollow fibers with in-situ confined and shaped phase change materials includes the following steps: Step 1, Preparation of oil phase system: The phase change material, acrylate composite monomer and ultraviolet photoinitiator are thoroughly mixed at room temperature to obtain a homogeneous and transparent oil phase; Step 2, Vacuum Infusion End Sealing: Select hollow polyester precursor yarn and use vacuum injection method to completely fill the inner cavity of the hollow fiber with the oil phase prepared in Step 1; after filling, use hot pressing process to heat melt seal both ends of the fiber to block the overflow channel of the inner cavity oil phase; Step 3, UV in-situ polymerization and confinement shaping: The filling fiber with sealed ends is placed in a UV irradiation environment. The UV light intensity and irradiation time are precisely controlled to cause the acrylate composite monomers in the cavity to undergo in-situ photopolymerization reaction, generating a continuous cross-linked polyacrylate three-dimensional network skeleton inside the hollow cavity. The three-dimensional network physically encapsulates and spatially confines the phase change material, forming a non-flowing and leak-proof solid phase change filling system. Step 4, High-temperature stretching and winding: The hollow fibers that have completed in-situ confined shaping are fed into a stretching device and subjected to hot stretching treatment in the temperature range of 100-180℃. After stretching, they are continuously wound to obtain the finished phase change temperature-regulating polyester fiber.

[0008] Preferably, the phase change material is any one or a combination of aliphatic hydrocarbons, fatty alcohols, fatty acids, and fatty acid esters as solid-liquid phase change energy storage materials; accounting for 60-90% of the oil phase content; Preferably, the acrylate composite monomer is composed of monofunctional acrylate and polyfunctional crosslinked acrylate, and the polyfunctional monomer is used to construct a crosslinked three-dimensional network. Preferably, the photoinitiator is an ultraviolet radical photoinitiator, and the amount added is 0.5% to 3% of the total mass of the acrylate composite monomers; Preferably, the vacuum level during vacuum infusion is controlled at -0.06 to -0.1 MPa to ensure that the oil phase completely wets the entire inner cavity of the hollow fiber; Preferably, the ultraviolet light wavelength range is 210-400 nm, and the irradiance is 200-800 mW / cm². 2 Irradiation time is 30–300 seconds to ensure full cross-linking of monomers within the cavity; Preferably, the hot stretching temperature is 120-160℃ and the stretching ratio is 1.2-3.0 times, which takes into account both the mechanical strength of the fiber and the integrity of the internal three-dimensional network.

[0009] As can be seen from the above technical solution, compared with the prior art, the present invention has the following technical effects: 1. This invention uses phase change materials, acrylate composite monomers and photoinitiators as raw materials to prepare an oil phase, completely solving the problem of leakage and precipitation of phase change materials: Unlike the simple physical encapsulation of hollow cavities, this invention generates a cross-linked polyacrylate three-dimensional network in situ within the fiber cavity, locking the phase change material in the network pores to form a solid composite system. No phase change medium is precipitated during thermal cycling, high-temperature stretching, water washing and long-term use, and the temperature control durability is greatly improved.

[0010] 2. Stable and controllable fiber properties and strong processing adaptability: The three-dimensional network in the inner cavity can support the hollow fiber tube wall. During high-temperature stretching, the inner cavity material does not flow or shift. The mechanical strength and breaking elongation of the finished fiber are uniform and stable, avoiding the fiber performance fluctuation defects of existing processes.

[0011] 3. Excellent and adjustable temperature control performance: The oil phase can fill the hollow cavity in a high proportion, the phase change material loading is high, and the fiber heat storage / release capacity is large; by changing the core material with different phase change temperatures and adjusting the monomer ratio, it can be adapted to the temperature control requirements of different scenarios.

[0012] 4. Continuous process and easy to scale up mass production: Vacuum infusion, UV curing, and hot stretching and winding can be connected in series to form a continuous production line. The process is simple, no high-temperature spinning is required, and the equipment investment is low, making it suitable for large-scale industrial production in textile enterprises.

[0013] 5. No damage to the polyester matrix: The maximum processing temperature is 200℃, which is lower than the thermal decomposition temperature of polyester. The structure of the hollow polyester filament is not damaged, and the finished product retains the original advantages of polyester fiber, such as wear resistance, wrinkle resistance and easy dyeing. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0015] Figure 1 This is a cross-sectional view of the phase change temperature-regulating polyester fiber after in-situ shaping by ultraviolet light irradiation in Example 1. Figure 2 Differential scanning calorimetry (DSC) spectra of the phase change temperature-regulating polyester fiber prepared in Example 1; Figure 3 The mechanical properties test diagram is shown for the phase change temperature-regulating polyester fiber prepared in Example 2. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 A method for preparing phase change temperature-regulating polyester fibers by filling hollow fibers with in-situ confined and shaped phase change materials includes the following steps: 1. Preparation of oil phase: Take 70 parts of octadecane phase change material, 25 parts of butyl methacrylate, and 5 parts of trimethylolpropane triacrylate (compounded acrylate monomers), add 1.5 parts of 1173 photoinitiator, stir at room temperature for 30 minutes, and mix evenly to obtain the oil phase; 2. Vacuum filling and sealing: Conventional hollow polyester yarn is selected, and the oil phase is injected under vacuum at a vacuum degree of -0.08MPa until the inner cavity of the fiber is completely wetted; the two ends of the fiber are sealed by heat fusion using a 180℃ hot press head. 3. In-situ UV polymerization: UV light intensity 400mW / cm 2 Irradiation for 120 seconds causes the acrylate monomers in the inner cavity to crosslink and form a three-dimensional polyacrylate network, which confines and shapes the octadecane phase change material. 4. Hot drawing: After setting, the fiber is fed into a hot drawing machine, the drawing temperature is 140℃, the drawing ratio is 2.0 times, and it is continuously wound to obtain phase change temperature-regulating polyester fiber.

[0018] Performance testing: No phase change material precipitation was observed after 500 cycles of hot and cold cycling; the fiber exhibited stable breaking strength, with a temperature difference adjustment range of 6–10℃, and its temperature regulation performance decreased by less than 5% after 50 washes. A cross-sectional view of the fiber is attached. Figure 1 As shown, the confined, shaped network structure within the hollow cavity is visible. Differential scanning calorimetry (DSC) results for the fibers are attached. Figure 2 As shown, the phase transition temperature of the fiber is in the range of 27-35℃, and the enthalpy value is as high as 46.5J / g.

[0019] Example 2 A method for preparing phase change temperature-regulating polyester fibers by filling hollow fibers with in-situ confined and shaped phase change materials includes the following steps: 1. Preparation of oil phase: 65 parts palmitol, 30 parts isooctyl acrylate, 5 parts pentaerythritol tetraacrylate, 2 parts TPO photoinitiator were added, and the mixture was stirred for 40 min to obtain a homogeneous oil phase; 2. Vacuum filling: Hollow polyester fiber is filled with a vacuum of -0.09MPa and sealed by heat fusion at 190℃; 3. UV curing: light intensity 600mW / cm² 2 Irradiation for 80 seconds resulted in the formation of a dense cross-linked network within the cavity; 4. Hot drawing forming: Temperature 160℃, draw ratio 1.8 times, winding to obtain high-temperature phase change thermoregulating polyester fiber. The tensile strength test results are shown below. Figure 3 It has a tensile strength of up to 3.5 cN / dtex and an elongation of about 12%. It is very suitable for use in underground and outdoor high-temperature protective fabrics.

[0020] Example 3 A method for preparing phase change temperature-regulating polyester fibers by filling hollow fibers with in-situ confined and shaped phase change materials includes the following steps: 1. Preparation of oil phase: 80 parts of lauric acid, 10 parts of butyl acrylate, 10 parts of methyl methacrylate, 3 parts of TPO photoinitiator were added and stirred for 30 min to obtain a homogeneous oil phase; 2. Vacuum filling: Hollow polyester fiber is filled with a vacuum of -0.08MPa and sealed by heat fusion at 200℃; 3. UV curing: light intensity 500mW / cm² 2 Irradiation for 120 seconds resulted in the formation of a dense cross-linked network within the cavity; 4. Hot stretching molding: Temperature 180℃, stretching ratio 2.2 times, to obtain high temperature phase change temperature-regulating polyester fiber.

[0021] Comparative Example 1 Only the n-octadecane from Example 1 was vacuum-infused into the hollow fibers, and the ends were sealed at 180°C. No UV in-situ polymerization step was performed; the fibers were directly drawn at 140°C. During processing, oil phase precipitation was observed at the fiber fracture ends, and significant phase change material exudation was observed after 50 cycles of thermal cycling. The temperature regulation properties of the fibers varied greatly across different areas after drawing, and the mechanical properties fluctuated significantly.

[0022] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing phase change temperature-regulating polyester fibers by filling hollow fibers with in-situ confined and shaped phase change material, characterized in that, Includes the following steps: Step 1: Mix the phase change material, acrylate composite monomers and photoinitiator to prepare a homogeneous oil phase; Step 2: The oil phase prepared in Step 1 is filled into the hollow cavity of the hollow polyester fiber by vacuum injection. After filling, the two ends of the fiber are heat-sealed. Step 3: Use ultraviolet light to irradiate the sealed fiber in step 2, control the light intensity and irradiation time, so that the acrylate composite monomers in the hollow cavity are polymerized in situ to generate a three-dimensional cross-linked network of polyacrylate. The phase change material is confined and shaped by the three-dimensional network to form a non-flowing solid phase change filling system. Step 4: The fibers that have completed in-situ confined shaping are hot-stretched and continuously wound at 100-180℃ to prepare phase change temperature-regulating polyester fibers.

2. The method for preparing phase change temperature-regulating polyester fiber by filling hollow fibers with in-situ confined and shaped phase change material according to claim 1, characterized in that, In step 1, the acrylate composite monomers include monofunctional acrylates and polyfunctional crosslinked acrylates, accounting for 10-40% of the oil phase content.

3. The method for preparing phase change temperature-regulating polyester fiber by filling hollow fibers with in-situ confined and shaped phase change material according to claim 2, characterized in that, In step 1, the phase change material is selected from one or more of aliphatic hydrocarbons, fatty alcohols, fatty acids and fatty acid esters solid-liquid phase change energy storage materials, and accounts for 60-90% of the oil phase content.

4. The method for preparing phase change temperature-regulating polyester fiber by filling hollow fibers with in-situ confined and shaped phase change material according to claim 3, characterized in that, The photoinitiator is an ultraviolet free radical photoinitiator, and its addition mass is 0.5% to 3% of the total mass of the acrylate composite monomers.

5. The method for preparing phase change temperature-regulating polyester fiber by filling hollow fibers with in-situ confined and shaped phase change material according to claim 1, characterized in that, The vacuum degree of vacuum injection in step 2 is -0.06 to -0.1 MPa, and the heat-sealing temperature is 180-200℃.

6. The method for preparing phase change temperature-regulating polyester fiber by filling hollow fibers with in-situ confined and shaped phase change material according to claim 1, characterized in that, In step 3, the ultraviolet light wavelength range is 210-400 nm, and the irradiation intensity is 200-800 mW / cm². 2 Irradiation time: 30–300 seconds.

7. The method for preparing phase change temperature-regulating polyester fiber by filling hollow fibers with in-situ confined and shaped phase change material according to claim 1, characterized in that, In step 4, the hot stretching temperature is 120–160℃ and the stretching ratio is 1.2–3.0 times.

8. The phase change temperature-regulating polyester fiber prepared by the method for preparing phase change temperature-regulating polyester fiber by filling hollow fibers with in-situ confined and shaped phase change material as described in any one of claims 1-7, characterized in that, The hollow fiber cavity contains a three-dimensional cross-linked polyacrylate network, and the phase change material is uniformly confined within the network pores, with no free liquid phase change medium.

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