Temperature response type printed color-changing fabric and preparation method thereof

Abstract

The invention discloses a temperature response type printed color-changing fabric and a preparation method thereof.The temperature response type printed color-changing fabric is prepared from polyester fiber base cloth and temperature-sensitive dye, and the temperature-sensitive dye is prepared from, by weight, 3-8 parts of microcapsule type thermochromic dye, 40-50 parts of organic silicon modified epoxy resin adhesive and 1-3 parts of thickening agent; the component A comprises the following components in parts by weight: 2-4 parts of a curing agent, 0.5-1.5 parts of a dispersing agent, 2-4 parts of a toughening agent and 1-2 parts of nano silicon dioxide, and the toughening agent comprises aminopropyl terminated polydimethylsiloxane and epoxy modified polydimethylsiloxane; the temperature response type printed color-changing fabric prepared by the method has excellent wear resistance and durability.

Description

Technical Field

[0001] This application relates to the field of functional textile materials technology, and in particular to a temperature-responsive printed color-changing fabric and its preparation method. Background Technology

[0002] Currently, with the continuous development of technology, people's functional requirements for textiles are increasing, especially for smart textiles that can respond to changes in the external environment. Temperature-responsive printed color-changing fabrics, as an important branch of smart textiles, have shown broad application prospects in clothing, home decoration, toys, and many other fields due to their unique color-changing properties. These fabrics typically achieve their color-changing effect by coating or printing a color-changing layer containing temperature-sensitive substances onto a substrate. When the ambient temperature changes, the substances in the color-changing layer undergo physical or chemical changes, thus causing a color change.

[0003] However, existing temperature-responsive printed color-changing fabrics have shortcomings in terms of durability and abrasion resistance. Due to the limited bonding strength between the color-changing layer and the substrate, the color-changing layer is prone to peeling or fading after repeated washing or prolonged use, resulting in a weakening or even disappearance of the color-changing effect. At the same time, the color-changing layer is also easily damaged when the fabric is subjected to friction or scratches, further affecting its service life and appearance quality. Summary of the Invention

[0004] To address the shortcomings in durability and abrasion resistance of temperature-responsive printed color-changing fabrics, a temperature-responsive printed color-changing fabric and its preparation method are provided.

[0005] The first inventive objective of this invention is achieved through the following technical solution: A temperature-responsive printed color-changing fabric is prepared from a base fabric and a temperature-sensitive dye, the temperature-sensitive dye comprising the following components in parts by weight: 3-8 parts of microencapsulated thermochromic dye, 40-50 parts of silicone-modified epoxy resin adhesive. Thickener 1-3 parts, 2-4 parts of hardener Dispersant 0.5-1.5 parts, 2-4 parts toughening agent 1-2 parts of nano-silica; Toughening agents include aminopropyl-terminated polydimethylsiloxane and epoxy-modified polydimethylsiloxane.

[0006] By adopting the above technical solution, the microencapsulated thermochromic dye encapsulates an electron donor (leuco dye), an electron acceptor (color developer), and a solvent medium. When the ambient temperature is lower than the solvent melting point, the solvent is solid, and the electron donor and acceptor are in close contact, resulting in proton transfer or charge transfer, and the dye is in a colored state. When the temperature rises to the solvent melting point, the solvent melts into a liquid state, the molecular activity increases dramatically, the donor and acceptor are separated by solvent molecules, the interaction is destroyed, and the dye returns to the leuco state. Macroscopically, this manifests as the disappearance or change of color, achieving temperature-sensitive color change. Silicone-modified epoxy resin adhesives introduce flexible polysiloxane segments into the rigid epoxy resin skeleton through chemical modification, achieving synergy and balance of performance. The epoxy resin component provides high strength, high crosslinking density and excellent adhesion to polyester fibers, forming a rigid support skeleton for the coating. The introduced silicone segments, with their excellent flexibility and hydrophobicity, can effectively absorb and disperse stress, improving the flexibility and crack resistance of the coating. Thickeners increase system viscosity by forming a three-dimensional network structure in the aqueous phase and impart strong shear-thinning properties. Curing agents react chemically with active functional groups (such as carboxyl and hydroxyl groups) on the polymer chains of the adhesive to form covalent bridges, connecting linear or branched macromolecules into a three-dimensional network structure. This enhances the coating's solvent resistance, chemical resistance, creep resistance, and mechanical strength, while improving dry / wet rubbing fastness, wash fastness, and adhesion to the base fabric. Dispersants adsorb onto the surface of thermochromic dyes, preventing aggregation through electrostatic repulsion or steric hindrance, ensuring uniformity and stability of color response. Nano-silica, as an inorganic nanofiller, is dispersed in the organic polymer network, improving the coating's mechanical strength, scratch resistance, and thermal stability, and scattering light to help regulate the color-changing effect. The aminopropyl-terminated polydimethylsiloxane can covalently bond with the adhesive network, thus chemically anchoring its own flexible polydimethylsiloxane long chain as a flexible segment within the polymer backbone of the coating. This reduces the rigidity of the crosslinked network and endows the coating with excellent elasticity and deformability. The epoxy groups of the epoxy-modified polydimethylsiloxane react with the active groups on the surface of the base fabric or in the adhesive, forming a chemical bridge at the interface between the coating and the base fabric. This introduces flexible siloxane segments into the interfacial region, improving the adhesion between the two and creating a flexible transition layer that can effectively buffer and disperse stress. The molecular-level design of "soft inside and attached outside" avoids the decrease in adhesion caused by simply increasing flexibility. It ensures that under external force, the stress from the base fabric to the coating can be uniformly and smoothly transmitted and released, thereby preventing interfacial peeling or coating cracking. It maintains a soft and comfortable feel similar to unprinted fabric and has strong and durable properties. In summary, by using an adhesive to solidify the network, the components are firmly integrated, and the functional components are protected and fixed in a composite layer that combines toughness, abrasion resistance, and strong adhesion. Ultimately, this enables the fabric to achieve sensitive and reversible thermochromic properties while possessing excellent washability, abrasion resistance, and long-term stability.

[0007] Optionally, the mass ratio of aminopropyl-terminated polydimethylsiloxane to epoxy-modified polydimethylsiloxane is 1:(2-4).

[0008] By adopting the above technical solution, aminopropyl-terminated polydimethylsiloxane serves as a reactive flexible segment regulator. Its amino groups react with epoxy groups to integrate them into the network. Epoxy-modified polydimethylsiloxane, as a flexible segment with both reactivity and compatibility, participates in the formation of the main network, while the siloxane chain provides flexibility. The mass ratio is 1:(2-4), ensuring that epoxy-modified polydimethylsiloxane, as the main flexible phase, forms a sufficiently continuous and uniformly distributed flexible region in the crosslinked network, effectively dissipating energy. At the same time, an appropriate amount of aminopropyl-terminated polydimethylsiloxane is added to further optimize the network structure, preventing excessive modulus reduction or weakening of adhesive cohesive strength due to excessive flexible phase. This allows the cured layer to achieve a balance between toughness, elastic recovery, and maintaining necessary stiffness and adhesion strength, improving the durability of the printed coating under dynamic mechanical stress.

[0009] Optionally, the nano-silica is modified with an epoxy silane coupling agent.

[0010] By adopting the above technical solution, the surface of unmodified nano-silica is rich in hydroxyl groups, has strong hydrophilicity, is prone to agglomeration in organic resin matrix, and has poor interfacial compatibility with hydrophobic resin, which has obvious defects. After surface grafting modification with epoxy silane coupling agent, the siloxane end of the coupling agent hydrolyzes and condenses with the hydroxyl groups on the silica surface to form a strong chemical bond, while the multifunctional epoxy groups at the other end are exposed. During the curing process, these epoxy groups can participate in the crosslinking reaction with the curing agent together with the epoxy groups of the organosilicon modified epoxy resin, thereby constructing a chemical bridge between the nano-silica particles and the resin matrix. This strong interfacial bonding ensures that stress is effectively transferred from the continuous resin phase to the high-modulus nanoparticles, while avoiding particle detachment due to weak interface, thus improving the wear resistance, water resistance and durability of the coating.

[0011] Optionally, the epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent.

[0012] By adopting the above technical solution, the molecular structure of γ-(2,3-epoxypropoxy)propyltrimethoxysilane has methoxysilane at one end, which can form stable Si-O-Si covalent bonds with the surface of nano-silica after hydrolysis; the other end is epoxypropoxy, which has high epoxy ring strain and high reactivity, and good compatibility and reactivity with epoxy resin matrix and curing agent. The propyl chain in between acts as a flexible spacer segment, which helps to relieve interfacial stress. This can achieve efficient and stable surface grafting modification of nano-silica and enhance the effect of nano-silica.

[0013] Optionally, the thickener is a nonionic polyurethane associative thickener.

[0014] By adopting the above technical solution, its molecular structure is a water-soluble polyurethane chain modified with hydrophobic end groups. In the aqueous system, its hydrophobic end groups undergo reversible association through intermolecular interactions to form a dynamic physical cross-linking network, thereby providing efficient thickening ability. Moreover, its non-ionic properties make it insensitive to the pH value and ionic strength of the system, and it has better compatibility and stability with other ionic components in the formulation. During the preparation and application of printing paste, this associated network can be temporarily destroyed under shear force and quickly rebuilt after the shear is removed, thereby giving the paste excellent rheological properties, ensuring clear outlines of printed patterns, uniform film thickness, enhanced color-changing effect and overall wear resistance and durability.

[0015] Optionally, the curing agent is an aziridine-based curing agent.

[0016] By adopting the above technical solution, which contains highly reactive three-membered cyclic amine groups, it can undergo ring-opening addition reaction with the adhesive under heating and curing conditions to form strong covalent bonds. It has high crosslinking efficiency and can form a three-dimensional network with high crosslinking density under relatively mild conditions. This dense network structure restricts the movement of polymer chain segments and macromolecules, which not only provides the coating with excellent chemical solvent resistance, hydrolysis resistance and creep resistance, but also locks all functional components and reinforcing components such as thermochromic microcapsules and nano silica firmly in the grid through physical constraint, ensuring the structural integrity and functional durability of the printed layer when facing external effects such as mechanical friction and repeated washing.

[0017] Optionally, the dispersant is a polyacrylic acid dispersant.

[0018] By adopting the above technical solution, the block or graft copolymer containing multiple anchoring groups and long hydrophilic chains is used. The anchoring groups are firmly adsorbed onto the surface of microcapsule dyes, nano-silica, and other particles through ionic bonds, hydrogen bonds, or van der Waals forces, while their long hydrophilic chains fully extend in water, forming a thick polymer steric hindrance layer around the particles, effectively preventing particle collision and aggregation. The polyacrylic acid dispersant has excellent compatibility with the aqueous system, enabling the solid particles to maintain a stable dispersion state during slurry storage and construction, thus improving the macroscopic uniformity of the printing coating components, enhancing the effect of each component, and improving the overall wear resistance and durability.

[0019] The second objective of this invention is achieved through the following technical solution: The preparation method of the above-mentioned temperature-responsive printed color-changing fabric includes the following steps: using screen printing technology, coating the base fabric with temperature-sensitive dye, and drying and curing to obtain the temperature-responsive printed color-changing fabric.

[0020] By adopting the above technical solution, screen printing can precisely apply a predetermined thickness of temperature-sensitive dye paste to a specific location on the base fabric by controlling the area and amount of paste penetration through the screen, forming a patterned functional coating. This helps to maintain the original distribution of paste components and reduce component separation or microcapsule breakage caused by severe shearing or turbulence. This method has strong process controllability, provides uniform component distribution, and has excellent overall performance.

[0021] In summary, this application has at least the following beneficial effects: (1) The silicone-modified epoxy resin adhesive chemically introduces flexible polysiloxane segments to balance performance. The epoxy component provides rigid support, and the silicone segments improve the coating's durability and wear resistance. (2) Aminopropyl-terminated polydimethylsiloxane, whose terminal aminopropyl groups are covalently bonded to the adhesive, anchors the flexible long chain to the coating skeleton, reduces rigidity, and enhances coating durability and abrasion resistance; (3) The epoxy groups of epoxy-modified polydimethylsiloxane form chemical bridges, introduce flexible segments, improve adhesion, and create a flexible transition layer. Its design prevents peeling and cracking, and takes into account both softness and durability. Detailed Implementation

[0023] raw material Microencapsulated thermochromic dye, model SW4360, color change temperature: 0℃-70℃, purchased from Shanghai Jingyan Chemical Co., Ltd. Silicone-modified epoxy resin adhesive, brand name HY-1540, was purchased from Shenzhen Huiya New Material Technology Co., Ltd. Acrylic adhesive, brand name Adwel® 1336, purchased from Wanhua Chemical Group Co., Ltd.; Nonionic polyurethane associative thickener, brand name ACRYSOL RM-12W, sourced from commercially available sources; The cellulose-based thickener, hydroxyethyl cellulose, was purchased from Feicheng Yutian Chemical Co., Ltd. Sodium polyacrylate thickener, solid content ≥90wt%, molecular weight ≥30 million, purchased from Shandong Chuangmu Biotechnology Co., Ltd. Aziridine-based curing agent, brand name Hafotex® P360, is sourced from commercially available sources; Carbodiimide curing agent, brand name Carbolinker D30, purchased from Kekong Co., Ltd.; Polyisocyanate curing agent, model S-402, purchased from Wuhan Shiquanxing New Material Technology Co., Ltd.; The polyacrylic acid dispersant, brand name Dispex® AA 4140, is from a commercially available source; Sodium dodecylbenzenesulfonate, purity ≥95wt%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Fatty alcohol polyoxyethylene ether, with an average molecular weight of 315, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Aminopropyl-terminated polydimethylsiloxane, molecular weight 3000, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. The epoxy-modified polydimethylsiloxane, which is a mono(2,3-epoxy)propyl ether-terminated polydimethylsiloxane, was purchased from Shanghai Yuanye Biotechnology Co., Ltd. Nano-silica, with an average particle size of 100nm, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560), γ-(2,3-epoxypropoxy)propyltriethoxysilane (KH-561), and γ-aminopropyltriethoxysilane (KH-550) were all purchased from Hangzhou Jessica Chemical Co., Ltd. The polyester fiber base fabric, anhydrous ethanol, and glacial acetic acid are all commercially available.

[0024] Preparation Example 1 A modified nano-silica, the preparation method of which is as follows: Mix 0.75 kg of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.36 kg of deionized water and 5 L of anhydrous ethanol, stir at 100 rpm for 10 min, add glacial acetic acid dropwise to adjust the pH to 4.5, and let stand for hydrolysis for 60 min to obtain an aqueous solution of γ-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent in ethanol. Add 20L of deionized water and 4L of anhydrous ethanol to the reactor, start stirring at 150 rpm, add 2.5kg of nano-silica, and stop stirring after the addition is complete. Use a high-speed shearing machine to shear and disperse the silica at 6000 rpm for 45 min. After dispersion, start stirring at 200 rpm, add γ-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent ethanol aqueous solution at a dropping rate of 5mL / s. After the addition is complete, raise the temperature to 75℃ at 1℃ / min and react for 7 h. Stop heating and stirring, and allow to cool naturally to 30℃. Filter the slurry after cooling to obtain a filter cake. Wash the filter cake three times with anhydrous ethanol. Place the washed filter cake in a forced-air drying oven and dry at 110℃ for 12 h to obtain modified nano-silica.

[0025] Preparation Example 2 A modified nano-silica, which differs from Preparation Example 1 in that γ-(2,3-epoxypropoxy)propyltriethoxysilane is used in place of γ-(2,3-epoxypropoxy)propyltrimethoxysilane by an equal mass; the rest is the same as Preparation Example 1.

[0026] Preparation Example 3 A modified nano-silica, which differs from Preparation Example 1 in that γ-aminopropyltriethoxysilane is used in place of γ-(2,3-epoxypropoxy)propyltrimethoxysilane by an equal mass; the rest is the same as Preparation Example 1.

[0027] Example 1 A temperature-responsive printed color-changing fabric is prepared from a polyester fiber base fabric and a thermosensitive dye. The thermosensitive dye is prepared from the following components by weight: 5 kg of microencapsulated thermochromic dye, 45 kg of silicone-modified epoxy resin binder, 2 kg of nonionic polyurethane associative thickener, 3 kg of aziridine curing agent, 1 kg of polyacrylic acid dispersant, 0.75 kg of aminopropyl-terminated polydimethylsiloxane, 2.25 kg of epoxy-modified polydimethylsiloxane, and 1.5 kg of modified nano-silica, wherein the modified nano-silica is derived from Preparation Example 1.

[0028] Its preparation method is as follows: S1: Add 45 kg of silicone-modified epoxy resin adhesive to a mixing tank. While stirring at 300 rpm, add 1 kg of polyacrylic acid dispersant and 1.5 kg of modified nano silica. Increase the stirring speed to 1000 rpm and disperse for 30 min. Reduce the speed to 400 rpm and add microcapsule-type thermochromic dye. After adding, increase the speed to 1000 rpm and disperse for 15 min. Reduce the speed to 500 rpm and add 0.75 kg of aminopropyl-terminated polydimethylsiloxane and 2.25 kg of epoxy-modified polydimethylsiloxane. Stir for 5 min. Add 2 kg of nonionic polyurethane associative thickener and 20 kg of deionized water. Stir for 10 min. Reduce the speed to 300 rpm and add 3 kg of aziridine curing agent. Stir for 10 min. Stop stirring and let stand for 30 min to obtain the thermosensitive dye. S2: The polyester fiber base is placed in a rotary screen printing machine, and temperature-sensitive dye is used for printing. The screen is 100 mesh, and the screen size can be 200cm × 50cm. The angle between the squeegee and the screen is 70°, the temperature is 40℃, the initial machine speed is 10m / min, the squeegee pressure is 0.5MPa, the squeegee speed is 1m / s, and two squeegees and one blade are used. After printing, it is dried and cured at 100℃ for 3 minutes. The dry weight coating amount is 30g / m². 2 The pattern is long stripes, with each stripe 2cm wide and the stripe spacing 8cm, resulting in a temperature-responsive printed color-changing fabric.

[0029] Comparative Example 1 A temperature-responsive printed color-changing fabric differs from Example 1 in that it does not contain aminopropyl-terminated polydimethylsiloxane; the rest is the same as Example 1.

[0030] Comparative Example 2 A temperature-responsive printed color-changing fabric differs from Example 1 in that it does not contain epoxy-modified polydimethylsiloxane; the rest is the same as Example 1.

[0031] Comparative Example 3 A temperature-responsive printed color-changing fabric differs from Example 1 in that it uses an acrylic adhesive instead of a silicone-modified epoxy resin adhesive; the rest is the same as Example 1.

[0032] Example 2 A temperature-responsive printed color-changing fabric differs from Example 1 in that it contains 1 kg of aminopropyl-terminated polydimethylsiloxane and 2 kg of epoxy-modified polydimethylsiloxane; the rest is the same as in Example 1.

[0033] Example 3 A temperature-responsive printed color-changing fabric differs from Example 1 in that: 0.6 kg of aminopropyl-terminated polydimethylsiloxane and 2.4 kg of epoxy-modified polydimethylsiloxane are used; the rest are the same as in Example 1.

[0034] Example 4 A temperature-responsive printed color-changing fabric differs from Example 1 in that it contains 1.5 kg of aminopropyl-terminated polydimethylsiloxane and 1.5 kg of epoxy-modified polydimethylsiloxane; the rest is the same as in Example 1.

[0035] Example 5 A temperature-responsive printed color-changing fabric differs from Example 1 in that: 0.5 kg of aminopropyl-terminated polydimethylsiloxane and 2.5 kg of epoxy-modified polydimethylsiloxane are used; the rest are the same as in Example 1.

[0036] Example 6 A temperature-responsive printed color-changing fabric, which differs from Example 1 in that the modified nano-silica is derived from Preparation Example 2; the rest is the same as Example 1.

[0037] Example 7 A temperature-responsive printed color-changing fabric differs from Example 1 in that the modified nano-silica is derived from Preparation Example 3; the rest is the same as Example 1.

[0038] Example 8 A temperature-responsive printed color-changing fabric differs from Example 1 in that it uses nano-silica of equal mass instead of modified nano-silica; the rest is the same as Example 1.

[0039] Example 9 A temperature-responsive printed color-changing fabric differs from Example 1 in that: a cellulose-based thickener is used instead of a nonionic polyurethane associative thickener; the rest is the same as Example 1.

[0040] Example 10 A temperature-responsive printed color-changing fabric differs from Example 1 in that it uses sodium polyacrylate thickener in place of nonionic polyurethane associative thickener; the rest is the same as Example 1.

[0041] Example 11 A temperature-responsive printed color-changing fabric differs from Example 1 in that it uses a carbodiimide curing agent of equal mass instead of a aziridine curing agent; the rest is the same as Example 1.

[0042] Example 12 A temperature-responsive printed color-changing fabric differs from Example 1 in that: a polyisocyanate curing agent is used instead of a aziridine curing agent by mass; the rest is the same as Example 1.

[0043] Example 13 A temperature-responsive printed color-changing fabric differs from Example 1 in that it uses sodium dodecylbenzenesulfonate in place of polyacrylic acid dispersant; the rest is the same as Example 1.

[0044] Example 14 A temperature-responsive printed color-changing fabric differs from Example 1 in that it uses fatty alcohol polyoxyethylene ether and other mass fractions instead of polyacrylic acid dispersants; the rest is the same as Example 1.

[0045] Example 15 A temperature-responsive printed color-changing fabric differs from Example 1 in that: 3 kg of microencapsulated thermochromic dye, 40 kg of silicone-modified epoxy resin adhesive, 1 kg of nonionic polyurethane associative thickener, 2 kg of aziridine curing agent, 0.5 kg of polyacrylic acid dispersant, 0.5 kg of aminopropyl-terminated polydimethylsiloxane, 1.5 kg of epoxy-modified polydimethylsiloxane, and 1 kg of modified nano-silica; the remaining components are the same as in Example 1.

[0046] Example 16 A temperature-responsive printed color-changing fabric differs from Example 1 in that: 8 kg of microencapsulated thermochromic dye, 50 kg of silicone-modified epoxy resin adhesive, 3 kg of nonionic polyurethane associative thickener, 4 kg of aziridine curing agent, 1.5 kg of polyacrylic acid dispersant, 1 kg of aminopropyl-terminated polydimethylsiloxane, 3 kg of epoxy-modified polydimethylsiloxane, and 2 kg of modified nano-silica; the remaining components are the same as in Example 1.

[0047] Examples 1-16 and Comparative Examples 1-3 were tested, and the results are as follows: According to GB / T 3920-2008 "Textiles - Tests for Color Fastness to Rubbing", two 50mm × 200mm samples were cut, one for dry rubbing and one for wet rubbing. All cut samples had the same stripe size and were located at the center of the sample. The samples were laid flat and fixed on the test machine's sample table with the printed side facing up and the length direction aligned with the rubbing direction. Dry rubbing: A standard white cotton cloth (compliant with GB / T 7568.2) was wrapped around the rubbing head. The rubbing head applied a force of 9N vertically downwards and rubbed the sample along a 100mm straight line at a speed of 1 cycle per second for 10 times. Wet rubbing: The sample and a new white cotton cloth were replaced. The cotton cloth was soaked in distilled water (moisture content 95%) and placed on the rubbing head. The rubbing head applied a force of 9N vertically downwards and rubbed the sample along a 100mm straight line at a speed of 1 cycle per second for 10 times. After rubbing, the white cotton cloth was air-dried at room temperature. Using GB / T 251-2008 "Textiles - Tests for Color Fastness - Assessment of Staining - Gray Scale", the staining grade of cotton fabric after dry and wet rubbing was assessed under a standard light source (D65). Grades ranged from 1 to 5, with grade 5 being the best (no staining) and grade 1 the worst. The test results are shown in Table 1. According to GB / T 12490-2014 "Textiles - Tests for Color Fastness to Household and Commercial Washing", 100mm × 40mm specimens were cut, with all cut specimens having the same stripe size and located at the center of the specimen. The printed surface was sewn to a 100mm × 40mm multifiber lining (or a specified single-fiber lining) fabric to form a composite specimen. The liquor ratio was 1:50, the washing solution was 4g / L standard soap flakes, and 10 stainless steel balls were added. The test was conducted at 50℃ and 40 rpm for 30 minutes. After the test, the composite specimen was washed twice with 40℃ tap water, then washed for 1 minute in running cold water. The water was squeezed out, the specimen was separated from the lining, and hung to dry in air at 25±5℃. Under standard light, the color change grade of the printed pattern was assessed using GB / T 250-2008 "Textiles - Tests for Color Fastness to Assessment of Color Change - Gray Scale". The staining grade of the lining fabric was assessed using GB / T 251-2008. All are rated from 1 to 5, with 5 being the best. The test results are shown in Table 1. According to GB / T 6152-1997 "Textiles - Tests for color fastness to heat and pressure", 100mm×40mm samples were cut, and all the stripes of the cut samples were of the same size and located in the center of the sample. The sample and the lining were in a dry state. The iron temperature was set to 200℃, and a pressure of 4kPa was applied to the sample for 15 seconds. After removing the iron, the color change grade of the sample was immediately evaluated using a gray scale. After the sample was conditioned under standard atmospheric conditions for 4 hours, the color change grade was evaluated again. The test results are shown in Table 2.

[0048] Table 1. Test results of abrasion resistance and washability

[0049] Table 2. Results of Color Fastness Test for Heat Pressing (Ironing)

[0050] Based on Tables 1 and 2, the analyses of Examples 1-16 and Comparative Examples 1-3 are as follows: Compared with Comparative Example 1, the dry and wet rubbing grades of the fabric in Example 1 after the abrasion test are both greater than those of the fabric in Comparative Example 1. The color fastness to washing and staining grades of the fabric in Example 1 after the washing test are both greater than those of the fabric in Comparative Example 1. The rating grades of the fabric in Example 1 immediately after ironing and after 4 hours after the hot pressing test are both greater than those of the fabric in Comparative Example 1.

[0051] The difference between Example 1 and Comparative Example 1 is that the sizing used in the fabric of Example 1 contains aminopropyl-terminated polydimethylsiloxane; the aminopropyl-terminated polydimethylsiloxane has end aminopropyl groups that can covalently bond with the adhesive network, anchoring the compliant long-chain chemical to the polymer backbone of the coating, reducing rigidity, and giving the coating elasticity and deformability; therefore, it is necessary to add aminopropyl-terminated polydimethylsiloxane to the sizing used in the fabric.

[0052] Comparing Example 1 and Comparative Example 2, the dry and wet rubbing grades of the fabric in Example 1 after the abrasion test are both greater than those of the fabric in Comparative Example 2. The color fastness to washing and staining grades of the fabric in Example 1 after the washing test are both greater than those of the fabric in Comparative Example 2. The rating grades of the fabric in Example 1 immediately after ironing and after 4 hours after the hot pressing test are both greater than those of the fabric in Comparative Example 2.

[0053] The difference between Example 1 and Comparative Example 2 is that the sizing used in the fabric of Example 1 contains epoxy-modified polydimethylsiloxane; the epoxy groups of epoxy-modified polydimethylsiloxane react to form chemical bridges, introduce flexible segments, improve adhesion, and construct a flexible transition layer. Its design ensures stress transfer and release, prevents peeling and cracking, and combines softness and durability; therefore, it is necessary to add epoxy-modified polydimethylsiloxane to the sizing used in the fabric.

[0054] Compared with Comparative Example 1 and Comparative Example 3, the dry rubbing grade and wet rubbing grade of the fabric in Example 1 after the abrasion test are both greater than those of the fabric in Comparative Example 3 after the abrasion test. The color fastness to washing and staining grades of the fabric in Example 1 after the washing test are both greater than those of the fabric in Comparative Example 3 after the washing test. The rating grades of the fabric in Example 1 immediately after ironing and after 4 hours after the hot pressing test are both greater than those of the fabric in Comparative Example 3 after the hot pressing test.

[0055] The difference between Example 1 and Comparative Example 3 is that the adhesive used in the fabric of Example 1 is a silicone-modified epoxy resin adhesive. The silicone-modified epoxy resin adhesive introduces flexible polysiloxane segments into the epoxy skeleton. The epoxy component provides high strength and rigidity support, while the silicone segments improve flexibility and crack resistance. Therefore, it is necessary for the adhesive used in the fabric to be a silicone-modified epoxy resin adhesive.

[0056] Comparing Examples 1 and 2-5, the abrasion resistance ratings of the fabric in Example 1 after the dry and wet rubbing tests are both higher than those of the fabrics in Examples 2-5. The colorfastness to washing and staining ratings of the fabric in Example 1 after the washing test are also higher than those of the fabrics in Examples 2-5. Furthermore, the ratings of the fabric in Example 1 immediately after ironing and after 4 hours after the hot-pressing test are also higher than those of the fabrics in Examples 2-5. Similarly, the abrasion resistance ratings of the fabrics in Examples 2-3 after the dry and wet rubbing tests are both higher than those of the fabrics in Examples 4-5. The colorfastness to washing and staining ratings of the fabrics in Examples 2-3 after the washing test are also higher than those of the fabrics in Examples 4-5. Finally, the ratings of the fabrics in Examples 2-3 immediately after ironing and after 4 hours after the hot-pressing test are also higher than those of the fabrics in Examples 4-5.

[0057] The difference between Example 1 and Examples 2-5 is that the mass ratio of aminopropyl-terminated polydimethylsiloxane and epoxy-modified polydimethylsiloxane added to the sizing agent used in Examples 1 and 2-3 is 1:(2-4). The aminopropyl-terminated and epoxy-modified polydimethylsiloxane are mixed in a ratio of 1:(2-4). The amino groups of the former are incorporated into the network, while the latter form a flexible region to dissipate energy. The two work together to optimize the structure and improve the dynamic durability of the printed coating. Therefore, the mass ratio of aminopropyl-terminated polydimethylsiloxane and epoxy-modified polydimethylsiloxane added to the sizing agent used in the fabric is 1:(2-4), which is more advantageous.

[0058] Comparing Examples 1 and 6-8, the abrasion resistance ratings of the fabric in Example 1 after the dry and wet rubbing tests are both higher than those of the fabrics in Examples 6-8. The colorfastness to washing and staining ratings of the fabric in Example 1 after the washing test are also higher than those of the fabrics in Examples 6-8. Furthermore, the ratings of the fabric in Example 1 immediately after ironing and after 4 hours after the hot-pressing test are both higher than those of the fabrics in Examples 6-8. Similarly, the abrasion resistance ratings of the fabrics in Examples 6-7 after the dry and wet rubbing tests are both higher than those of the fabric in Example 8. Finally, the colorfastness to washing and staining ratings of the fabrics in Examples 6-7 after the washing test are also higher. The grades of the fabrics in Examples 6 and 7 after the hot-press test are all higher than those of the fabrics in Example 8 after the washing test for color fastness to washing, color change, and staining. The grades of the fabrics in Examples 6 and 7 after the hot-press test, both immediately after ironing and after 4 hours, are also higher than those of the fabrics in Example 8 after the hot-press test. The grades of the fabrics in Example 7 after the abrasion test, both dry and wet, are also higher than those of the fabrics in Example 8 after the abrasion test. The grades of the fabrics in Example 7 after the washing test for color fastness to washing, color change, and staining are also higher than those of the fabrics in Example 8 after the washing test. The grades of the fabrics in Example 7 after the hot-press test, both immediately after ironing and after 4 hours, are also higher than those of the fabrics in Example 8 after the hot-press test.

[0059] The difference between Examples 1 and Examples 6-8 is that the nano-silica added to the sizing agent used in the fabric of Example 8 was not modified, while the nano-silica added to the sizing agent used in the fabrics of Examples 1 and 6 was modified with an epoxy silane coupling agent. Furthermore, the nano-silica added to the sizing agent used in the fabric of Example 1 was modified with a γ-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent. Unmodified nano-silica tends to agglomerate easily due to the hydrophilic nature of its hydroxyl groups and has poor compatibility. Modification with epoxy silanes, however, leads to hydrolysis and condensation. The chemical bridging and strong interfacial bonding enhance the overall performance of the coating. γ-(2,3-epoxypropoxy)propyltrimethoxysilane hydrolyzes into Si-O-Si bonds at one end, while the epoxy group at the other end is highly active. The propyl chain provides stress relief and can efficiently and stably modify nano-silica. Therefore, the nano-silica added to the slurry used in the fabric is better modified by epoxy silane coupling agent, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent is the best choice.

[0060] Comparing Examples 1 and 9-10, the dry and wet rubbing grades of the fabric in Example 1 after the abrasion test are both greater than those of the fabrics in Examples 9-10. The color fastness to washing and staining grades of the fabric in Example 1 after the washing test are both greater than those of the fabrics in Examples 9-10. The rating grades of the fabric in Example 1 immediately after ironing and after 4 hours after the hot pressing test are both greater than those of the fabrics in Examples 9-10.

[0061] The difference between Example 1 and Examples 9-10 is that the thickener added to the paste used in Example 1 is a nonionic polyurethane associative thickener; the hydrophobic end-modified water-soluble polyurethane chain forms a dynamic physical cross-linking network in the aqueous system for thickening, and the nonionic properties provide good stability, imparting rheological properties to the paste and improving printing quality and durability; therefore, it is better to use a nonionic polyurethane associative thickener as the thickener added to the paste used in the fabric.

[0062] Comparing Example 1 and Example 11-12, the dry and wet rubbing grades of the fabric in Example 1 after the abrasion test are both greater than those of the fabric in Example 11-12. The color fastness to washing and staining grades of the fabric in Example 1 after the washing test are both greater than those of the fabric in Example 11-12. The rating grades of the fabric in Example 1 immediately after ironing and after 4 hours after the hot pressing test are both greater than those of the fabric in Example 11-12.

[0063] The difference between Example 1 and Examples 11-12 is that the curing agent added to the paste used in the fabric of Example 1 is an aziridine-based curing agent; it contains highly active three-membered cyclic amine groups, which undergo ring-opening addition with the adhesive during heating and curing to form a high cross-linking density network, improve coating performance, lock in functional components, and ensure the long-lasting stability of the printed layer; therefore, it is better to use an aziridine-based curing agent as the curing agent added to the paste used in the fabric.

[0064] Comparing Examples 1 and 13-14, the dry and wet rubbing grades of the fabric in Example 1 after the abrasion test are both greater than those of the fabric in Example 13-14. The color fastness to washing and staining grades of the fabric in Example 1 after the washing test are both greater than those of the fabric in Example 13-14. The rating grades of the fabric in Example 1 immediately after ironing and after 4 hours after the hot pressing test are both greater than those of the fabric in Example 13-14.

[0065] The difference between Example 1 and Examples 13-14 is that the dispersant added to the sizing agent used in the fabric of Example 1 is a polyacrylic acid dispersant; it is a copolymer containing anchoring groups and long hydrophilic chains, which adsorbs onto the surface of particles to form a steric hindrance layer to prevent agglomeration, has good compatibility with water-based systems, and ensures uniform printing coating, wear resistance and durability; therefore, it is better to add a polyacrylic acid dispersant to the sizing agent used in the fabric.

[0066] Comparing Examples 1 and 15-16, the dry and wet rubbing grades of the fabric in Example 1 after the abrasion test are both greater than those of the fabric in Example 15-16. The color fastness to washing and staining grades of the fabric in Example 1 after the washing test are both greater than those of the fabric in Example 15-16. The rating grades of the fabric in Example 1 immediately after ironing and after 4 hours after the hot pressing test are both greater than those of the fabric in Example 15-16.

[0067] The difference between Example 1 and Examples 15-16 is that the mass ratio of microencapsulated thermochromic dye, silicone-modified epoxy resin adhesive, nonionic polyurethane associative thickener, aziridine curing agent, polyacrylic acid dispersant, aminopropyl-terminated polydimethylsiloxane, epoxy-modified polydimethylsiloxane, and modified nano-silica in the sizing used in the fabric of Example 1 is 5:45:2:3:1:0.75:2.25:1.5. Therefore, the mass ratio of microencapsulated thermochromic dye, silicone-modified epoxy resin adhesive, nonionic polyurethane associative thickener, aziridine curing agent, polyacrylic acid dispersant, aminopropyl-terminated polydimethylsiloxane, epoxy-modified polydimethylsiloxane, and modified nano-silica in the sizing used in the fabric of Example 1 is superior.

[0068] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of protection claimed by the present invention, they are protected by patent law.

Claims

1. A temperature-responsive printed color-changing fabric, characterized in that, It is prepared from polyester fiber base fabric and thermosensitive dye, wherein the thermosensitive dye comprises the following components in parts by weight: 3-8 parts of microencapsulated thermochromic dye, 40-50 parts of silicone-modified epoxy resin adhesive. Thickener 1-3 parts, 2-4 parts of hardener Dispersant 0.5-1.5 parts, 2-4 parts toughening agent 1-2 parts of nano-silica; The toughening agent includes aminopropyl-terminated polydimethylsiloxane and epoxy-modified polydimethylsiloxane.

2. The temperature-responsive printed color-changing fabric according to claim 1, characterized in that, The mass ratio of the aminopropyl-terminated polydimethylsiloxane to the epoxy-modified polydimethylsiloxane is 1:(2-4).

3. The temperature-responsive printed color-changing fabric according to claim 1, characterized in that, The nano-silica is modified with an epoxy silane coupling agent.

4. The temperature-responsive printed color-changing fabric according to claim 3, characterized in that, The epoxy silane coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane coupling agent.

5. The temperature-responsive printed color-changing fabric according to claim 1, characterized in that, The thickener is a nonionic polyurethane associative thickener.

6. The temperature-responsive printed color-changing fabric according to claim 1, characterized in that, The curing agent is a aziridine-based curing agent.

7. The temperature-responsive printed color-changing fabric according to claim 1, characterized in that, The dispersant is a polyacrylic acid dispersant.

8. A method for preparing a temperature-responsive printed color-changing fabric according to any one of claims 1-7, characterized in that, Includes the following steps: Temperature-responsive printed color-changing fabric is obtained by applying temperature-sensitive dyes to the base fabric using screen printing technology and then drying and curing it.

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