A method for preparing an ambient temperature responsive polyester knit

Abstract

The application discloses a preparation method of an ambient temperature response polyester knitted fabric, which comprises the following steps: spraying a UCST solution on one side of a polyester knitted fabric, and irradiating the polyester knitted fabric with ultraviolet rays to obtain the ambient temperature response polyester knitted fabric; the UCST solution is prepared by mixing a UCST type temperature-sensitive polymer monomer, a photoinitiator, a solvent, a crosslinking agent and water; and then the mixed solution is stirred and placed under constant temperature conditions; the ambient temperature response polyester knitted fabric is prepared by the synergistic effect of the temperature-sensitive hydrophilic-hydrophobic conversion of the UCST type temperature-sensitive polymer and the loop aperture, active response of the fabric to ambient temperature is realized, the fabric has the functions of low-temperature warmth and high-temperature cooling, and the problem of single function of traditional textiles is solved; the excellent characteristics of the polyester fabric are retained, the moisture permeation amount is increased by 32% through grafting modification, the thermal stability is improved, and the dual optimization of function and performance is realized.

Description

Technical Field

[0001] This invention relates to a method for preparing an environmental temperature-responsive polyester knitted fabric, belonging to the field of intelligent textile materials technology. It can automatically adjust hydrophilicity, moisture permeability and heat retention through temperature changes, and realize intelligent regulation of the thermal and moisture balance of the human body's microenvironment. It is suitable for outdoor adventure clothing, military combat clothing, high-temperature work clothing (such as metallurgical and chemical industries) and daily commuting and leisure clothing, and can especially meet the wearing comfort requirements in complex temperature change environments. Background Technology

[0002] With consumption upgrades and technological advancements, consumers' functional needs for clothing are shifting from "basic clothing" to "intelligent comfort," with the management of the body's microenvironment for heat and moisture becoming a core requirement. In scenarios such as outdoor sports, military missions, and special occupations, environmental temperatures fluctuate greatly (e.g., the temperature difference between day and night outdoors can reach more than 15°C, and the temperature in high-temperature work environments can exceed 40°C). Traditional textiles can only achieve a single function through fixed warmth-keeping or breathability structures, and cannot dynamically adjust their performance according to environmental changes—they are unable to effectively lock in heat at low temperatures and cannot quickly dissipate heat and wick away moisture at high temperatures, leading to wearers experiencing coldness or stuffiness and discomfort.

[0003] Existing heat and humidity management textiles have significant technical limitations: radiation temperature-regulating fabrics (such as the multifunctional coupled radiation temperature-enhancing fabric developed by Du Peibo's team) rely on the principle of infrared radiation reflection / absorption and can only passively adapt to the ambient temperature, unable to actively respond; unidirectional moisture-wicking fabrics achieve unidirectional moisture transfer through fiber structure design, but lack temperature sensitivity and are prone to causing a cold feeling due to moisture residue in low-temperature environments; although phase change material fabrics can regulate temperature through the latent heat of phase change, the phase change temperature is fixed, the cycle stability is poor, and humidity cannot be synergistically regulated.

[0004] Thermosensitive polymers offer a new direction for smart textile materials, as their physical properties, such as hydrophilicity / hydrophobicity and volume, can change with temperature. Current research suffers from two major shortcomings: First, the research focuses on a limited base, primarily cotton fabrics. Polyester fabrics, however, account for over 50% of the textile market due to their superior abrasion resistance (wear rate is only 1 / 3 that of cotton), wrinkle resistance (wrinkle recovery angle is 20°-30° higher than cotton), and easy handling (no ironing required after washing). However, traditional polyester fabrics have poor moisture absorption (moisture regain of only 0.4%) and insufficient thermal and humidity comfort, resulting in very little research on thermosensitive modification. Second, the research is limited by polymer type. Existing studies mostly use low critical solution temperature (LCST) thermosensitive polymers, which are hydrophobic at temperatures above LCST, contradicting the human body's need for hydrophilic moisture wicking when sweating at high temperatures. High critical solution temperature (UCST) thermosensitive polymers, on the other hand, are hydrophilic at temperatures above UCST, better suited to the human body's thermal and humidity management needs. However, there is currently no technical solution to combine these polymers with polyester knitted fabrics. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing environmental temperature responsive polyester knitted fabric. Through a dual mechanism of "thermosensitive polymer property transformation + coil structure synergy", the fabric can achieve intelligent response to environmental temperature, dynamically regulate heat and moisture transmission performance, and improve the comfort of wearers in different temperature environments.

[0006] To solve the above-mentioned technical problems, the objective of this invention is achieved as follows: The present invention relates to a method for preparing an environmental temperature responsive polyester knitted fabric, which involves spraying a UCST solution onto one side of the polyester knitted fabric and then irradiating it with ultraviolet light to obtain an environmental temperature responsive polyester knitted fabric. The UCST solution is prepared by mixing UCST-type thermosensitive polymer monomers, photoinitiators, solvents, crosslinking agents, and aqueous phases to obtain a mixed solution; the mixed solution is then stirred and allowed to stand under constant temperature conditions.

[0007] Based on the above scheme and as a preferred embodiment of the above scheme: the UCST type thermosensitive polymer monomer is N,N-dimethyl (methacryloyloxyethyl) aminopropanesulfonic acid inner salt.

[0008] Based on the above scheme and as a preferred embodiment of the above scheme: the photoinitiator is 2,2-diethoxyacetophenone.

[0009] Based on the above scheme and as a preferred embodiment of the above scheme: the solvent is 2,2,2-trifluoroethanol.

[0010] Based on the above scheme and as a preferred embodiment of the above scheme: the crosslinking agent is ethylene glycol dimethacrylate.

[0011] Based on the above scheme and as a preferred embodiment of the above scheme: the polyester knitted fabric is a polyester weft plain knitted fabric.

[0012] Based on the above scheme and as a preferred embodiment of the above scheme: the mixed solution is placed in a 40 ℃ water bath, stirred with a magnetic stirrer for 2 hours, and then allowed to stand for 30 minutes.

[0013] Based on the above scheme and as a preferred embodiment of the above scheme: the UCST is sprayed onto one side of the polyester knitted fabric at a distance of 15 cm from the polyester knitted fabric using a spray gun.

[0014] Based on the above scheme and as a preferred embodiment of the above scheme, the ultraviolet treatment time is 40 minutes.

[0015] The beneficial effects of this invention are as follows: The method for preparing an environmental temperature-responsive polyester knitted fabric involves a synergistic effect of the thermosensitive hydrophilic-hydrophobic transformation of a UCST-type thermosensitive polymer and the coil aperture, enabling the fabric to actively respond to environmental temperatures, providing warmth at low temperatures and cooling at high temperatures, thus solving the problem of single functionality in traditional textiles. It retains the excellent properties of polyester fabrics while simultaneously increasing moisture permeability by 32% and improving thermal stability through graft modification, achieving a dual optimization of "function + performance". Attached Figure Description

[0016] Figure 1 These are SEM microstructure images and mapping analysis diagrams of polyester knitted fabrics and UCST. Figure 2 This is a graph showing the temperature changes on the surface of human skin covered by UCST-polyester fabric and polyester base fabric. Figure 3 This is a comparison image of UCST-polyester fabric and polyester raw fabric covering human skin surface sweat absorption; Figure 4 This shows the changes in the appearance of PDMAPS solutions at different temperatures. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0018] The present invention relates to a method for preparing an ambient temperature responsive polyester knitted fabric, wherein a UCST solution is sprayed onto one side of the polyester knitted fabric and then irradiated with ultraviolet light to obtain an ambient temperature responsive polyester knitted fabric; the UCST solution is obtained by mixing a UCST-type thermosensitive polymer monomer, a photoinitiator, a solvent, a crosslinking agent and an aqueous phase to obtain a mixed solution; the mixed solution is then stirred and allowed to stand under constant temperature conditions.

[0019] Specifically, using polyester weft-knitted fabric as the base, a single-sided grafting process is adopted to form a double-layer structure of "UCST type thermosensitive polymer layer - polyester fiber layer" on the fabric surface. The single-sided grafting is used to construct a wettability gradient in the thickness direction. At the same time, combined with the loop hole structure of the weft-knitted fabric, a control system of "heat-driven wettability gradient + loop hole synergy" is formed.

[0020] The UCST-type thermosensitive polymer is poly[N,N-dimethyl(methacryloyloxyethyl)aminopropanesulfonic acid inner salt (PDMAPS)] formed by free radical polymerization of N,N-dimethyl(methacryloyloxyethyl)aminopropanesulfonic acid inner salt (DMAPS). The UCST (high critical solution temperature) of this polymer is 31.4-32.5 ℃, which is highly matched with the human body's comfortable temperature range (25-37 ℃).

[0021] Thermosensitive polymer monomer DMAPS, photoinitiator 2,2-diethoxyacetophenone (DEAP), 2,2,2-trifluoroethanol, crosslinking agent ethylene glycol dimethacrylate, and deionized water were mixed to obtain a mixed solution. The mixed solution was placed in a 40 ℃ water bath and stirred with a magnetic stirrer for 2 h, and then allowed to stand for 30 min.

[0022] Transfer the prepared UCST solution to the spray gun and spray the solution onto one side of the polyester knitted fabric from a distance of 15 cm.

[0023] The polyester knitted fabric coated with UCST solution was placed 30 cm in front of a UV lamp and irradiated for 40 min to complete the UV-induced grafting reaction, resulting in a polyester knitted fabric with temperature-responsive intelligent humidity and heat management.

[0024] This fabric exhibits reversible hydrophilic / hydrophobic transition properties. When the ambient temperature is below the phase transition temperature of the UCST-type thermosensitive polymer, the UCST-type thermosensitive polymer becomes hydrophobic, reducing the difference in wettability between the two sides of the fabric and decreasing the coil aperture, thus hindering heat transfer and moisture transport and achieving a warming effect. When the ambient temperature is above the phase transition temperature, the UCST-type thermosensitive polymer becomes hydrophilic, forming a wettability gradient in the thickness direction of the fabric, increasing the coil aperture, thus promoting heat dissipation and moisture transport and achieving a cooling effect.

[0025] The moisture permeability (WVTR) of the fabric was measured at different temperatures of 20 ℃ and 40 ℃ and different humidity levels of 50%RH, 70%RH and 90%RH.

[0026] WVTR= (1) In formula (1), WVTR is the moisture permeability of the fabric, expressed in g·m³. -2 ·d -1 Δm is the mass difference between the two weighings, in grams, and A is the effective area of ​​the test sample, in square meters. 2 Δt is the time difference between two weighings, in hours.

[0027] Low temperature environment (temperature ~20 ℃): PDMAPS is hydrophobic, the difference in wettability between the two sides of the fabric is reduced (contact angle difference <10°), the coil aperture shrinks to about 210.25μm, hindering heat transfer (thermal conductivity coefficient reduced by 15-20%) and moisture transfer (moisture permeability reduced by 10-12%), achieving a warming effect, with a temperature 4.5 ℃ higher than the original polyester fabric.

[0028] High-temperature environment (temperature ~40℃): PDMAPS exhibits hydrophilicity, creating a wettability gradient along the fabric thickness (the contact angle on the coated side drops to 0° within 4 seconds, and on the uncoated side, it drops to 0° within 5 seconds). The coil aperture expands to approximately 218.79 μm, promoting heat dissipation (increasing the thermal conductivity by 25-30%) and moisture transfer (moisture permeability reaches 8925.69 g·m at 40℃). -2 ·d -1 It is 2870.49 g·m higher than that of polyester raw fabric. -2 ·d -1 This achieves a cooling effect, with a temperature 1.6 ℃ lower than that of the original polyester fabric.

[0029] By leveraging the thermosensitive hydrophobic / hydrophilic conversion of PDMAPS and the synergistic effect of coil aperture, the fabric achieves an active response to ambient temperature, providing warmth at low temperatures and cooling at high temperatures, thus solving the problem of limited functionality in traditional textiles. It retains the excellent properties of polyester fabrics (abrasion resistance, wrinkle resistance), while grafting modification increases moisture permeability by 32% and improves thermal stability, achieving a dual optimization of "function + performance".

[0030] Employing single-sided spraying and ultraviolet grafting technology, it is simple to operate (no complex equipment required), low in cost (ultraviolet light energy consumption is only 1 / 5 of that of traditional thermal induced coating), and highly efficient (single batch processing time < 4 hours), making it suitable for industrial mass production.

[0031] After 20 cold water washes, the fabric contact angle change rate is less than 8% and the moisture permeability decrease rate is less than 10%, maintaining good thermal and moisture management performance and meeting the durability requirements for daily wear.

[0032] Preparation of USCT-type polymer PDMAPS: The raw materials were mixed in the following mass ratio: DMAPS:photoinitiator DEAP:solvent 2,2,2-trifluoroethanol:crosslinking agent ethylene glycol dimethacrylate:deionized water = 10:0.5:20:1:68.5. The mixed solution was placed in a 40 ℃ constant temperature water bath and magnetically stirred at 300 r / min for 2 h. After standing for 30 min to remove bubbles, a homogeneous solution was obtained and placed in a photoinitiator catalytic device for polymerization to obtain UCST-type polymer PDMAPS. This was used to test its temperature-sensitive response characteristics.

[0033] The prepared PDMAPS solution and deionized water were injected into two separate cuvettes, as follows: Figure 4As shown, the appearance of the solution was observed when the temperature was increased from 0 ℃ to 60 ℃ and then decreased from 60 ℃ back to 0 ℃. At 0 ℃, the UCST solution was milky white. As the temperature increased, the UCST solution gradually changed from cloudy to clear. At 60 ℃, the UCST solution was transparent, almost identical in appearance to deionized water. However, when the temperature was lowered back to 0 ℃, the UCST solution became cloudy again. After repeating the above operation multiple times, the UCST solution still exhibited the same transformation behavior, which shows that the UCST solution has a reversible temperature response behavior.

[0034] To more clearly compare the two-phase differences of the UCST solution, the transmittance of the UCST solution was tested at 0 ℃ and 60 ℃. At 0 ℃, the transmittance of the UCST solution was only 1.44%, indicating that PDMAPS exhibited a hydrophobic state. However, at 60 ℃, the transmittance of the UCST solution reached as high as 92.45%, and the solution was clear and transparent, indicating that PDMAPS exhibited a hydrophilic state at this temperature. Therefore, PDMAPS possesses the characteristics of UCST-type polymers and exhibits good temperature-sensitive hydrophilic / hydrophobic transition, and this transition behavior is reversible.

[0035] The raw materials were mixed in the following mass ratio: DMAPS:photoinitiator DEAP:solvent 2,2,2-trifluoroethanol:crosslinking agent ethylene glycol dimethacrylate:deionized water = 10:0.5:20:1:68.5. The mixed solution was placed in a 40 ℃ constant temperature water bath and magnetically stirred at 300 r / min for 2 h. After standing for 30 min to remove air bubbles, a solution of uniform concentration was obtained. Polyester weft-knitted fabric (weight 180 g / m²) was then used. 2 Cut the coil (28 stitches / inch) into 15×15cm size, ultrasonically clean with deionized water for 15 min (to remove surface oil), dry in a 60℃ oven for 2 h, and fix it on a smooth cardboard (to avoid fabric wrinkles affecting the uniformity of spraying).

[0036] Inject the UCST solution into the spray gun (nozzle diameter 0.5 mm), adjust the spray gun pressure to 0.3 MPa, and spray at a uniform speed (spraying speed 5 cm / s) at a distance of 15 cm from the fabric, controlling the spraying amount to 5 g / cm. 2 To ensure a uniform polymer coating is formed only on one side of the fabric, the coated fabric was placed 30 cm in front of a 300 W UV lamp (wavelength 254 nm) and irradiated for 40 min at 25 °C in the dark. This UV light initiated the polymerization reaction between DMAPS monomers and the polyester fiber surface. The modified fabric was then dried in a 60 °C oven for 2 h to remove residual solvents and unreacted monomers, yielding a UCST-type thermosensitive polymer-grafted polyester knitted fabric (polymer grafting amount 20.4%).

[0037] Five μL of water was dropped onto both sides of the polyester fabric and the intelligent humidity and heat management polyester knitted fabric, and the movement of the water droplets was monitored. At 20°C, the contact angles on both sides of the uncoated polyester fabric remained at 132.5°, exhibiting good hydrophobicity. At 20°C, after the temperature-sensitive polyester knitted fabric was coated with the temperature-sensitive polymer, the PDMAPS polymer exhibited hydrophobicity due to the temperature being lower than UCST, with a contact angle of 101.2°.

[0038] At 40 °C, water droplets on both sides of the polyester fabric remained spherical, but the contact angle decreased compared to 20 °C, reaching 131.6°. This temperature is higher than the UCST. On the side of the thermosensitive polyester knitted fabric coated with the thermosensitive polymer, the droplet became hydrophilic, and the droplet spread rapidly. However, when a droplet was placed on the uncoated side, it penetrated to the coated side and spread there. This indicates that the droplet wicks moisture from the hydrophobic side to the hydrophilic side. The moisture-wicking capacity of the thermosensitive polyester knitted fabric is determined by the wetting gradient constructed by the hydrophilic / hydrophobic properties on both sides of the fabric. When there is a significant difference in wetting properties on both sides of the fabric, the fabric has the ability to transport water in one direction, with moisture transferring from the hydrophobic side to the hydrophilic side and spreading there.

[0039] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing an environmental temperature-responsive polyester knitted fabric, characterized in that, UCST solution was sprayed onto one side of a polyester knitted fabric and then irradiated with ultraviolet light to obtain an ambient temperature responsive polyester knitted fabric. The UCST solution is prepared by mixing UCST-type thermosensitive polymer monomers, photoinitiators, solvents, crosslinking agents, and aqueous phases to obtain a mixed solution; then the mixed solution is stirred and allowed to stand under constant temperature conditions.

2. The method for preparing an environmental temperature-responsive polyester knitted fabric according to claim 1, characterized in that, The UCST-type thermosensitive polymer monomer is N,N-dimethyl (methacryloyloxyethyl) aminopropanesulfonic acid inner salt.

3. The method for preparing an environmental temperature-responsive polyester knitted fabric according to claim 1, characterized in that, The photoinitiator is 2,2-diethoxyacetophenone.

4. The method for preparing an environmental temperature-responsive polyester knitted fabric according to claim 1, characterized in that, The solvent is 2,2,2-trifluoroethanol.

5. The method for preparing an environmental temperature-responsive polyester knitted fabric according to claim 1, characterized in that, The crosslinking agent is ethylene glycol dimethacrylate.

6. The method for preparing an environmental temperature-responsive polyester knitted fabric according to claim 1, characterized in that, The polyester knitted fabric is a polyester weft plain knitted fabric.

7. The method for preparing an environmental temperature-responsive polyester knitted fabric according to claim 1, characterized in that, The mixed solution was placed in a 40 °C water bath and stirred with a magnetic stirrer for 2 hours, then allowed to stand for 30 minutes.

8. The method for preparing an environmental temperature-responsive polyester knitted fabric according to claim 1, characterized in that, The UCST is applied using a spray gun, sprayed onto one side of the polyester knitted fabric at a distance of 15 cm.

9. The method for preparing an environmental temperature-responsive polyester knitted fabric according to claim 1, characterized in that, The UV treatment time is 40 minutes.

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