Anti-wrinkle memory function polyester printed fabric and preparation method thereof

Abstract

The application discloses an anti-wrinkle memory functional polyester printing fabric and a preparation method thereof, and belongs to the technical field of polymer materials and textile engineering. The fabric is prepared from a skin-core type composite polyester fiber through weaving, pre-roller dyeing, heat setting, printing and steaming and fixing. The skin layer of the skin-core type composite polyester fiber contains sulfonic acid groups, and the core layer contains aromatic disulfide bonds and polyether soft segments. The application introduces sulfonic acid groups and aromatic disulfide bonds into the fiber by adopting a skin-core homologous structure design, thereby solving the technical problem that the anti-wrinkle memory function and the printing performance are difficult to be considered simultaneously. The dynamic exchange of the disulfide bonds at the heat setting temperature realizes the chemical cross-linking of the skin-core interface, the condensation temperature and the steaming temperature are optimized, and the antioxidant is protected, so that the retention rate of the disulfide bonds is greater than or equal to 95%. The obtained fabric has a wrinkle recovery angle greater than or equal to 280 degrees, a memory retention rate greater than or equal to 90% after 50 times of washing, and a printing washing fastness greater than or equal to 4.5 levels, and the unity of the anti-wrinkle memory, the high color fastness printing and the spinning stability is realized.

Description

Technical Field

[0001] This invention relates to the fields of polymer materials and textile engineering technology, and in particular to an anti-wrinkle memory polyester printed fabric and its preparation method. Background Technology

[0002] Polyester fiber is widely used in the textile and apparel industry due to its advantages such as high strength, excellent abrasion resistance, and controllable cost. Polyester fabrics that combine wrinkle-resistant memory function with high color fastness printing have become a core demand in the high-end market. Existing wrinkle-resistant memory polyester is mostly achieved by introducing flexible segments, shape memory components, or dynamic covalent bonds, but they generally suffer from problems such as limited functionality and difficulty in simultaneously achieving wrinkle resistance and printability.

[0003] To improve the dyeing and printing performance of polyester, cationic modification of polyester is often used in industry. This involves introducing sulfonic acid groups to enhance dye uptake and color fastness. However, this type of modification reduces the fiber's thermal stability and has poor compatibility with anti-wrinkle memory functional components. Some technologies attempt to use dynamic bonds such as disulfide bonds for anti-wrinkle modification, but these suffer from weak bonding with the polyester matrix, easy decomposition at high temperatures, and insufficient memory durability. Furthermore, according to research published in the *Journal of Polymer Science*, the thermal decomposition temperature of aromatic disulfide bonds reaches 300-333℃, indicating that their stable application potential has not been fully explored. Core-sheath composite fiber technology achieves complementary performance through functional partitioning, but conventional systems often use general-purpose resins with large melting point differences, leading to problems such as mismatched melt viscosities between the sheath and core layers, poor spinning stability, and easy peeling of the sheath and core.

[0004] Existing solutions still have significant shortcomings: commercially available modified monomers and auxiliaries cannot simultaneously meet the synergistic requirements of printing uniformity, wrinkle memory, and high-temperature processing stability; simple physical blending easily leads to component aggregation and functional degradation. Existing technologies either focus only on optimizing a single function or have complex processes and high industrialization difficulty, failing to achieve the comprehensive goal of "durable wrinkle memory, high printing color fastness, and stable mass production through spinning." Therefore, this invention combines the high-temperature stability of aromatic disulfide bonds with the printing compatibility of sulfonation modification, optimizes the core-sheath structure and process parameters, and provides a high-performance wrinkle memory functional polyester printed fabric and its preparation method. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a wrinkle-resistant memory polyester printed fabric and its preparation method.

[0006] The technical solutions provided by the embodiments of the present invention are as follows: A wrinkle-resistant memory polyester printed fabric and its preparation method include the following steps: S1. Preparation of the skin layer polyester: S101. Sodium dimethyl isophthalate-5-sulfonate and triethylene glycol are added to a reaction vessel at a molar ratio of 1:1.5-1:2.5. Tetrabutyl titanate catalyst is added in an amount of 0.05-0.1% of the total mass of the reactants. The reaction is carried out at 170-190℃ for 3 hours under nitrogen protection. The methanol generated is collected through a fractionating column. After the reaction is completed, the unreacted triethylene glycol is removed by vacuum distillation to obtain the printing modifier. Under nitrogen protection, the two methyl ester groups (-COOCH3) in the dimethyl isophthalate-5-sulfonate (SIPM) molecule undergo transesterification with the hydroxyl groups (-OH) at both ends of the triethylene glycol molecule. Triethylene glycol has a linear short-chain structure, and the primary hydroxyl groups at both ends have high reactivity. In the reaction system, tetrabutyl titanate acts as a catalyst, which activates the carbonyl carbon through the coordination of titanium atoms with the carbonyl oxygen, enhancing its electrophilicity. Subsequently, the terminal hydroxyl oxygen atoms of triethylene glycol attack the activated carbonyl carbon to form a tetrahedral intermediate. Finally, the methoxy group leaves in the form of methanol, a new ester bond is formed, and the catalyst is regenerated to enter the next cycle. Each SIPM molecule can react with two molecules of triethylene glycol to generate a linear structure with hydroxyl groups at both ends. The reaction is carried out at a temperature of 170-190℃, which ensures sufficient reactivity for smooth transesterification while avoiding side reactions such as decomposition of sulfonic acid groups or breakage of triethylene glycol ether bonds caused by excessively high temperatures. The printing modifier generated by the reaction is a short-chain polyether ester containing sulfonic acid groups. Its molecular structure is formed by alternating ester bonds between the benzene ring (containing sodium sulfonate group) of SIPM and triethylene glycol segments. The short-chain structure of triethylene glycol (only three ethoxy units) allows for precise control of the molecular chain length of the modifier, avoiding the defects of long-chain polyethylene glycol such as easy crystallization and poor thermal stability. The introduction of sulfonic acid groups endows the modifier with permanent hydrophilicity and cationic dye seat function, while the triethylene glycol segments provide moderately flexible connecting arms, improving compatibility with the polyester backbone.

[0007] After the reaction was completed, the product was distilled under reduced pressure at 190℃ and -0.095MPa for 40-60 min. By taking advantage of the difference in boiling point between triethylene glycol (boiling point 285℃) and the product (higher molecular weight), unreacted triethylene glycol and low-boiling-point byproducts were removed to obtain a printing modifier with a purity ≥98%. S102. Terephthalic acid, ethylene glycol and printing modifier are esterified at 230-240℃ for 2 hours. Tetrabutyl titanate is used as a catalyst. Then, polycondensation is carried out under high temperature and high vacuum to obtain the skin polyester. The above describes the polyester synthesis process, which includes two stages: esterification and polycondensation. Esterification stage: Terephthalic acid and ethylene glycol undergo esterification at 230-240℃. The two carboxyl groups of terephthalic acid react with the hydroxyl groups of ethylene glycol to generate diethyl terephthalate and water. At the same time, the hydroxyl groups at both ends of the printing modifier molecule also participate in the reaction, acting as chain extenders. They copolymerize with the carboxyl groups of terephthalic acid or the ester bonds already formed in the system, introducing sulfonic acid groups into the polyester backbone. Tetrabutyl titanate acts as a catalyst, activating the carboxyl groups through coordination and accelerating the reaction. The water generated in the reaction is continuously discharged from the system, pushing the equilibrium to the right.

[0008] Polycondensation stage: After the esterification reaction is basically completed, the temperature is raised and a vacuum is drawn to enter the polycondensation stage. At this time, the bis(hydroxyethyl) terephthalate molecules are connected to each other through transesterification reaction, ethylene glycol is removed, and high molecular weight polyester chains are gradually formed. The printing modifier is embedded in the polyester backbone through the reactive groups at both ends, and the sulfonic acid groups are suspended on the molecular chain as side groups. As polycondensation proceeds, the viscosity of the system gradually increases and the molecular weight continues to increase. Under vacuum conditions, the generated ethylene glycol is removed in time to allow the polycondensation reaction to continue, and finally the skin polyester containing sulfonic acid groups is obtained. S2, Preparation of the core layer polyester: S201. Add 4,4'-dithiobenzoic acid and polytetrahydrofuran to a reactor at a molar ratio of 1:2.1, then add tetrabutyl titanate catalyst at a mass of 0.05-0.1% of the total reactants. After purging with nitrogen three times, heat to 180-190℃ and maintain the temperature for 4 hours. During the reaction, intermittently apply vacuum to remove the generated water. When the acid value drops below 5 mg KOH / g, discharge the material while hot and cool to room temperature to obtain an aromatic disulfide chain extender with a number average molecular weight of 2200-2500 and a purity ≥95%. In the reaction system, the two carboxyl groups of 4,4'-dithiodibenzoic acid and the hydroxyl groups at both ends of polytetrahydrofuran undergo esterification under the catalysis of tetrabutyl titanate. When feeding, polytetrahydrofuran is in excess (molar ratio 2.1:1) to ensure that both ends of the reaction product are hydroxyl-terminated, avoiding the formation of an asymmetric structure with one end of carboxyl group and the other end of hydroxyl group. Tetrabutyl titanate acts as a catalyst, activating the carbonyl carbon through the coordination of titanium atoms with carboxyl oxygen, promoting the nucleophilic attack of hydroxyl groups, and accelerating the formation of ester bonds. The reaction temperature is controlled at 180-190℃. This temperature ensures the esterification reaction rate and is below the thermal decomposition temperature of the disulfide bond to avoid the disulfide bond being destroyed. Nitrogen gas is continuously introduced during the reaction to prevent the disulfide bond from being oxidized at high temperature. Intermittent vacuuming is used to remove the generated water in time, break the reversible equilibrium of the esterification reaction, push the reaction to the right, and improve the conversion rate.

[0009] The reaction was stopped when the acid value dropped below 5 mg KOH / g, indicating that there were very few residual carboxyl groups in the system and the esterification reaction was basically complete. The product was discharged while hot because it may solidify at room temperature. After cooling, a polyether-aryl sulfide-polyether triblock chain extender with hydroxyl groups at both ends was obtained, with a number average molecular weight of about 2200-2500. This molecular weight is controlled by the feed ratio and the degree of reaction. The hydroxyl groups retained at both ends can directly participate in the subsequent polycondensation reaction of the core layer polyester, introducing disulfide bonds and polyether soft segments into the polyester main chain. Aromatic disulfide chain extenders play a dual role in the system as a memory function carrier and a bridge for introducing soft segments: Structurally, this chain extender is a polyether-aryl sulfide-polyether triblock structure with hydroxyl groups at both ends: the 4,4'-dithiobenzoic acid in the middle provides aromatic disulfide bonds, and the polytetrahydrofurans at both ends provide flexible segments. In the subsequent polycondensation reaction of the core layer polyester, the hydroxyl groups at both ends of the chain extender undergo co-condensation with the diethyl terephthalate oligomer generated in the esterification stage, embedding the disulfide bonds and polyether soft segments into the polyester backbone. The core function of aromatic disulfide bonds in the system is as "dynamic cross-linking points". At the heat setting temperature (150-160℃), the disulfide bonds undergo a reversible exchange reaction, which allows the polyester molecular chains to rearrange to adapt to the new conformation, thereby "remembering" the set shape. At the temperature of daily use, the disulfide bonds remain stable and fix the shape. This dynamic reversible characteristic gives the fabric the memory function of repeated shaping and long-term retention. The role of polytetrahydrofuran soft segments is to regulate the memory trigger temperature and improve the hand feel. The introduction of soft segments lowers the glass transition temperature of the core polyester, allowing the molecular chains to undergo chain segment movement at lower temperatures (such as human body temperature or warm water washing). Combined with the dynamic exchange of disulfide bonds, shape recovery is achieved. At the same time, the presence of soft segments also increases the flexibility of the molecular chains, preventing the fabric from becoming stiff due to the introduction of disulfide bonds. In addition, the design of this chain extender also solves two key problems: First, it fixes the disulfide bonds in the polyester backbone through chemical bonds, avoiding the defects of easy migration and uneven distribution of small molecule chain extenders; Second, it improves the compatibility between disulfide bonds and polyester matrix through polyether soft segments, so that disulfide bonds can be evenly distributed at the molecular level, ensuring the stability and durability of memory function. S202. Terephthalic acid and ethylene glycol are esterified at 225-235℃ for 3 hours, with tetrabutyl titanate as catalyst, the amount of which is 0.03-0.06% of the mass of terephthalic acid. Aromatic disulfide chain extender and antioxidant are added and polycondensed under high vacuum at 250-260℃ for 3.5 hours to obtain core layer polyester. The synthesis of the core layer polyester is divided into two steps: esterification followed by polycondensation. In the esterification stage, terephthalic acid and ethylene glycol react at 225-235℃. The two carboxyl groups are esterified with the hydroxyl groups of two molecules of ethylene glycol to generate diethyl terephthalate and water. Tetrabutyl titanate acts as a catalyst, which activates the carbonyl carbon through the coordination of titanium atoms with carboxyl oxygen, accelerating the nucleophilic attack of hydroxyl groups. The water generated in the reaction is continuously discharged from the system, pushing the reversible equilibrium to the right and making the esterification reaction more complete. After esterification, the polycondensation stage begins. At this point, an aromatic disulfide chain extender is added. This chain extender has hydroxyl groups at both ends and polytetrahydrofuran soft segments and aromatic disulfide bonds in the middle. Under high vacuum conditions of 250-260℃, bis(hydroxyethyl) terephthalate molecules are interconnected through a polycondensation reaction, removing ethylene glycol and gradually forming high molecular weight polyester chains. At the same time, the hydroxyl groups of the chain extender also participate in the polycondensation reaction, incorporating their disulfide bonds and polyether soft segments into the polyester backbone. As the polycondensation proceeds, the viscosity of the system gradually increases, and ethylene glycol is promptly removed, allowing the reaction to continue to advance to the right.

[0010] The role of antioxidants at this stage is to capture free radicals that may be generated at high temperatures and protect disulfide bonds from thermal oxidative degradation. The disulfide bonds in aromatic disulfide bond extenders remain stable at 250-260℃ (their decomposition temperature is about 317-320℃), thus being completely preserved in the polyester molecular chain. As polycondensation proceeds, the viscosity of the system gradually increases. Ethylene glycol is promptly removed, allowing the reaction to continue moving to the right. The final product is a block copolymer of terephthalic acid-ethylene glycol hard segments and polyether soft segments containing disulfide bonds, which are arranged alternately. The hard segments provide mechanical strength and melting point, while the soft segments regulate the memory trigger temperature. The disulfide bonds, as dynamic crosslinking points, impart shape memory function. S3, core-sheath composite spinning: After drying the polyester chips for the sheath and core layers, they are melt-extruded into the two screw extruders of a sheath-core composite spinning machine. The sheath spinning temperature is 250-260℃, and the core spinning temperature is 260-270℃. Composite spinning is carried out through a sheath-core composite spinneret. The melt viscosity ratio of the sheath to the core layer is controlled to be 0.9-1.1, the sheath-core mass ratio is 35-40:60-65, and the spinning speed is 1200-1400m / min. After cooling, oiling, and winding, pre-oriented yarn is obtained, and then drawn and deformed to obtain sheath-core composite polyester fiber. Core-sheath composite spinning is a process in which two polyester materials with different functions are combined into a single fiber in a molten state through a spinneret. Its core lies in utilizing the difference in melt flow behavior between the two materials to achieve a stable concentric circle structure. Before spinning, the sheath polyester and core polyester chips are dried to remove moisture and prevent hydrolytic degradation at high temperatures. The two polyesters are then added to two independently controlled screw extruders for heating and melting. The sheath spinning temperature is controlled at 250-260℃, slightly higher than its melting point of 210-220℃; the core spinning temperature is controlled at 260-270℃, slightly higher than its melting point of 245-255℃. This temperature gradient design ensures that the two polyesters have suitable melt flowability in their respective extruders, while also preparing them for subsequent compounding. Two melts are precisely metered by a metering pump and simultaneously enter the core-sheath composite spinneret assembly. Within the spinneret channels, the higher-viscosity core melt is completely enveloped by the lower-viscosity skin melt, forming a concentric circle melt stream. The viscosity ratio of the skin to the core melt is controlled within the range of 0.9-1.1, which is crucial for ensuring the stability of the core-sheath structure. If the ratio is too high (the skin is too thick and the core is too thin), the skin cannot uniformly envelop the core, easily leading to eccentricity or core exposure. If the ratio is too low (the skin is too thin and the core is too thick), the skin melt may be punctured by the core, also causing structural damage. After being extruded from the spinneret, the melt stream immediately enters the side-blowing cooling zone, where it rapidly solidifies under the action of cooling air, fixing the concentric circle structure and forming a core-sheath nascent fiber. Both the outer layer polyester and the core layer polyester have terephthalic acid-ethylene glycol as the main chain structure, but the functional segments introduced are different. This similarity in chemical structure makes the two polyesters have similar solubility parameters in the molten state and low interfacial tension. When the melts come into contact, a certain degree of molecular chain interdiffusion can occur to form a physically bonded transition layer. After cooling, this transition layer firmly bonds the outer layer and the core layer together, avoiding interfacial delamination during subsequent processing. From the perspective of functional zoning, the outer layer of the fiber comes into direct contact with the skin and dyes during subsequent wear. The sulfonic acid groups introduced into the polyester of the outer layer give it hydrophilicity and cationic dyeing sites, making the fabric soft, skin-friendly and non-itchy. At the same time, the dyes can be fully applied and achieve high color fastness during printing. The core layer, as the skeleton of the fiber, undertakes mechanical support and memory function. The disulfide bonds and polyether soft segments embedded in the core polyester give it a high melting point and glass transition temperature. At heat setting temperatures, the disulfide bonds undergo reversible exchange to achieve shape memory, while maintaining dimensional stability at everyday use temperatures. This specialized design of "skin-friendly printing on the outer layer and wrinkle-resistant memory on the inner layer" allows a single fiber to simultaneously fulfill two seemingly contradictory functional requirements. After the nascent fibers are oiled and wound to obtain pre-oriented yarn, they still need to undergo stretching and deformation processing. During the stretching process, the fiber molecular chains are aligned along the axial direction, the crystallinity and orientation are improved, and the mechanical properties are significantly enhanced. The stretching ratio is controlled at 1.6-1.8 times, the stretching temperature is 90-110℃, and the heat setting temperature is 140-150℃. The stretching and heat setting at this stage further stabilize the core-sheath structure and orient the molecular chains of the sheath and core layers respectively, ultimately obtaining a core-sheath composite polyester fiber that meets the weaving requirements. S4. Weaving and Pre-dyeing Treatment: Core-sheath type composite polyester fibers are warped and woven to obtain greige fabric, which is then pre-dyed with disperse-cationic composite dyes. After the core-sheath composite polyester fiber is warped and woven to obtain the greige fabric, the pre-dyeing treatment is an "activation" step to prepare for subsequent printing. The core of this process is to use the sulfonic acid groups introduced in the polyester sheath to establish a uniform dye adsorption layer on the fiber surface through the physicochemical interaction between the dispersed-cationic composite dye and the fiber, laying the foundation for the full dyeing of the dye during the formal printing. The pre-padding dyeing process uses disperse-cationic composite dyes. These composite dyes are produced by reacting cationic dyes with substances containing anions (such as naphthalenesulfonic acid) to form an insoluble complex, which is then compounded with disperse dyes. The modified composite dyes can be used in the same bath as disperse dyes without coagulation or precipitation, thus ensuring the stability of the dye bath. During processing, the greige fabric is immersed in a composite dye solution and then squeezed by rollers. The dye solution is forced to penetrate into the gaps between fibers and the amorphous areas on the fiber surface. In this process, the sulfonic acid groups (-SO3) in the polyester skin layer... - As an anionic active site, it electrostatically binds to the cationic components in the composite dye through ionic bonds, causing the dye molecules to be "anchored" to the fiber surface. This binding is rapid and strong, and can be initially fixed during the pre-drying stage (80-90℃). Cationic dyes interact with sulfonic acid-containing fibers according to the charge molar ratio. This ionic bond has good stability and can resist the erosion of subsequent washing. For disperse dye components, they mainly adhere to the fiber surface through physical adsorption during the pre-dyeing stage, preparing for diffusion and fixation during subsequent high-temperature steaming. The significance of pre-dyeing treatment is that it allows cationic dyes to pre-occupy the sulfonic acid dye sites in the skin layer, avoiding uneven dyeing caused by dye competition during formal printing; at the same time, the uniform pre-adsorption layer also provides a uniform "starting point" for the thermal migration and fixation of the subsequent disperse dyes, thereby effectively improving the clarity and color fastness of the final printed pattern. S5. Heat setting and printing: The pre-dyed fabric is heat-set at a temperature of 150-160℃ for 60-80 seconds. Disperse-cationic composite dyes are used to print on the heat-set fabric. Then, the fabric is steamed and fixed at 155-160℃ for 9-11 minutes. After reduction, washing, and drying, wrinkle-resistant memory polyester printed fabric is obtained. The heat setting process is carried out at 150-160℃ for 60-80 seconds. This temperature is just enough to trigger the reversible dynamic exchange of disulfide bonds in the core layer: on the one hand, it releases the internal stress of the fiber and sets the fabric into a flat shape; on the other hand, the exchange reaction of disulfide bonds extends to the core-sheath interface, forming cross-linking with the sheath molecular chains, upgrading the physical bond to a chemical bond. At the same time, the sheath (Tg) has been greatly exceeded, and the composite dyes adsorbed by pre-dyeing further diffuse into the amorphous region, and the bond with sulfonic acid groups is more solid. After heat setting, printing is performed, followed by steaming and fixing at 155-160℃ for 9-11 minutes. This temperature window is precisely designed: it is below the disulfide bond thermal decomposition temperature (~300℃), but above the fixation threshold of disperse dyes, and is within the dynamic exchange range of disulfide bonds. Saturated steam causes the skin layer to swell, and the cationic components in the composite dye are anchored to the sulfonic acid groups in the skin layer through ionic bonds. The disperse dye dissolves and diffuses into the amorphous region of the skin layer to form a solid solution. The disulfide bonds in the core layer maintain dynamic exchange but are not thermally degraded (antioxidant protection, retention rate ≥95%). The thermal buffering effect of the skin layer makes the actual temperature of the core layer slightly lower, further ensuring the safety of the disulfide bonds. Steaming followed by reduction cleaning removes surface dye: cationic dyes ionically bonded to sulfonic acid groups and disperse dyes already dissolved in polyester are not stripped.

[0011] Preferably, the polyester skin comprises the following components by weight: 100 parts terephthalic acid, 40-50 parts ethylene glycol, and 15-25 parts printing modifier; wherein the printing modifier is prepared by transesterification reaction of sodium dimethyl isophthalate-5-sulfonate and triethylene glycol, and has a purity ≥98%.

[0012] Preferably, the core layer polyester comprises the following components by weight: 100 parts terephthalic acid, 50-60 parts ethylene glycol, 15-30 parts aromatic disulfide chain extender, and 0.1-0.2 parts antioxidant.

[0013] Preferably, the intrinsic viscosity of the outer polyester layer is 0.52-0.58 dL / g, the glass transition temperature is 55-60℃, and the sulfonic acid group content is 0.4-0.6 mmol / g; the intrinsic viscosity of the core polyester layer is 0.65-0.72 dL / g, the glass transition temperature is 75-85℃, and the disulfide bond content is 0.4-0.6 mmol / g.

[0014] Preferably, the amount of tetrabutyl titanate added in S102 is 0.02-0.05% of the mass of terephthalic acid, and the polycondensation conditions are: polycondensation temperature 250-260℃, vacuum degree 100Pa, and time 3h.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention employs a core-sheath composite polyester fiber homogeneous structure design, coupled with precise partitioning of functional segments in the sheath and core layers, solving the technical challenge of simultaneously achieving wrinkle-resistant memory function and printing performance in traditional polyester fabrics. This invention uses polyethylene terephthalate (PET) as the main chain backbone, introducing sulfonic acid groups into the sheath layer to impart permanent hydrophilicity and cationic dyeing sites, achieving high color fastness and a skin-friendly feel for printing; embedding aromatic disulfide bonds and polyether soft segments in the core layer, through the synergistic effect of dynamic covalent bonds and flexible segments, endows the fabric with shape memory function. The melting point difference between the sheath and core layers is controlled at 25-40℃, and the melt viscosity ratio is 0.9-1.1, ensuring spinning stability and interfacial bonding, allowing a single fiber to simultaneously bear the dual functions of "skin-friendly printing on the outer layer and wrinkle-resistant memory on the inner layer," breaking through the limitations of single-material performance.

[0016] 2. This invention employs a block copolymer chain extender design combining aromatic disulfide bonds and polyether soft segments, along with the reversible exchange mechanism of dynamic covalent bonds, to overcome the shortcomings of small molecule chain extenders, such as easy migration, uneven distribution, and insufficient durability of memory function. This invention synthesizes a polyether-aryl sulfide-polyether triblock chain extender with hydroxyl ends through the esterification reaction of 4,4'-dithiobenzoic acid and polytetrahydrofuran, fixing the disulfide bonds to the polyester backbone in the form of chemical bonds, ensuring their uniform distribution at the molecular level. At the heat setting temperature (150-160℃), the disulfide bonds undergo reversible exchange, causing the polyester molecular chain to reconstruct and "remember" the set shape; the introduction of polyether soft segments simultaneously adjusts the memory trigger temperature (approximately 50-60℃) and improves the hand feel, endowing the fabric with a memory function that can be repeatedly shaped and remains stable over a long period. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the core-sheath type composite polyester fiber of the present invention; Figure 2 This is a flowchart illustrating the preparation process of the wrinkle-resistant memory function polyester printed fabric of the present invention. Detailed Implementation

[0018] The technical solutions of this invention are described below. It should also be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments; those skilled in the art can also use other alternative methods to implement some well-known technologies.

[0019] In the following examples and comparative examples, the catalyst was tetrabutyl titanate, and the amount added was 0.05% of the mass of terephthalic acid.

[0020] Example 1: Preparation of wrinkle-resistant memory polyester printed fabric: S1. Preparation of the skin layer polyester: S101. Sodium dimethyl isophthalate-5-sulfonate and triethylene glycol were added to a reaction vessel at a molar ratio of 1:2. Tetrabutyl titanate was added at 0.05% of the total mass of the reactants. The reaction was carried out at 180°C for 3 hours under nitrogen protection. The methanol generated was collected by fractionation column. After the reaction was completed, the unreacted triethylene glycol was removed by vacuum distillation to obtain the printing modifier. S102. By weight, 100 parts of terephthalic acid, 45 parts of ethylene glycol and 15 parts of printing modifier are esterified at 235°C for 2 hours. A catalyst is added and then polycondensed at 255°C under a vacuum of 100Pa for 3 hours to obtain the skin polyester. S2, Preparation of the core layer polyester: S201. 4,4'-Dithiodibenzoic acid and polytetrahydrofuran were added to a reaction vessel at a molar ratio of 1:2.1. Then, tetrabutyl titanate catalyst (0.05% of the total mass of the reactants) was added. After nitrogen purging three times, the temperature was raised to 185℃ and the reaction was maintained for 4 hours. During the reaction, the generated water was removed by intermittent vacuuming. When the acid value dropped below 5 mg KOH / g, the product was discharged while hot and cooled to room temperature to obtain an aromatic disulfide chain extender with a number average molecular weight of 2300 and a purity ≥95%. S202. By weight, 100 parts of terephthalic acid and 55 parts of ethylene glycol are subjected to esterification reaction at 230°C for 3 hours. A catalyst is added, the amount of which is 0.05% of the mass of terephthalic acid. 22 parts of aromatic disulfide chain extender and 0.1 parts of antioxidant are added. Polycondensation is carried out at 255°C under high vacuum for 3.5 hours to obtain the core layer polyester. S3, core-sheath composite spinning: After drying the polyester chips for the sheath and core layers, they are melt-extruded into the two screw extruders of a sheath-core composite spinning machine. The sheath spinning temperature is 255℃ and the core spinning temperature is 265℃. Composite spinning is carried out through a sheath-core composite spinneret. The melt viscosity ratio of the sheath to the core layer is controlled to be 1, the sheath-core mass ratio is 40:60, and the spinning speed is 1300m / min. After cooling, oiling, and winding, pre-oriented yarn is obtained, and then the sheath-core composite polyester fiber is obtained through stretching and deformation. S4. Weaving and Pre-dyeing Treatment: Core-sheath type composite polyester fibers are warped and woven to obtain greige fabric, which is then pre-dyed with disperse-cationic composite dyes. S5. Heat setting and printing: The pre-dyed fabric is heat-set at 155℃ for 70 seconds. Disperse-cationic composite dyes are then used to print on the heat-set fabric. The fabric is then steamed at 160℃ for 10 minutes, followed by reduction cleaning and drying to obtain wrinkle-resistant memory polyester printed fabric.

[0021] Example 2: Preparation of wrinkle-resistant memory polyester printed fabric: S1. Preparation of the skin layer polyester: S101. Sodium dimethyl isophthalate-5-sulfonate and triethylene glycol were added to a reaction vessel at a molar ratio of 1:2. Tetrabutyl titanate was added at 0.05% of the total mass of the reactants. The reaction was carried out at 180°C for 3 hours under nitrogen protection. The methanol generated was collected by fractionation column. After the reaction was completed, the unreacted triethylene glycol was removed by vacuum distillation to obtain the printing modifier. S102. By weight, 100 parts of terephthalic acid, 45 parts of ethylene glycol and 20 parts of printing modifier are esterified at 235°C for 2 hours. A catalyst is added and then polycondensed at 255°C under a vacuum of 100Pa for 3 hours to obtain the skin polyester. S2, Preparation of the core layer polyester: S201. 4,4'-Dithiodibenzoic acid and polytetrahydrofuran were added to a reaction vessel at a molar ratio of 1:2.1. Then, tetrabutyl titanate catalyst (0.05% of the total mass of the reactants) was added. After nitrogen purging three times, the temperature was raised to 185℃ and the reaction was maintained for 4 hours. During the reaction, the generated water was removed by intermittent vacuuming. When the acid value dropped below 5 mg KOH / g, the product was discharged while hot and cooled to room temperature to obtain an aromatic disulfide chain extender with a number average molecular weight of 2300 and a purity ≥95%. S202. By weight, 100 parts of terephthalic acid and 55 parts of ethylene glycol are subjected to esterification reaction at 230°C for 3 hours. A catalyst is added, the amount of which is 0.05% of the mass of terephthalic acid. 15 parts of aromatic disulfide chain extender and 0.1 parts of antioxidant are added. Polycondensation is carried out at 255°C under high vacuum for 3.5 hours to obtain the core layer polyester. S3, core-sheath composite spinning: After drying the polyester chips for the sheath and core layers, they are melt-extruded into the two screw extruders of a sheath-core composite spinning machine. The sheath spinning temperature is 255℃ and the core spinning temperature is 265℃. Composite spinning is carried out through a sheath-core composite spinneret. The melt viscosity ratio of the sheath to the core layer is controlled to be 1, the sheath-core mass ratio is 40:60, and the spinning speed is 1300m / min. After cooling, oiling, and winding, pre-oriented yarn is obtained, and then the sheath-core composite polyester fiber is obtained through stretching and deformation. S4. Weaving and Pre-dyeing Treatment: Core-sheath type composite polyester fibers are warped and woven to obtain greige fabric, which is then pre-dyed with disperse-cationic composite dyes. S5. Heat setting and printing: The pre-dyed fabric is heat-set at 155℃ for 70 seconds. Disperse-cationic composite dyes are then used to print on the heat-set fabric. The fabric is then steamed at 160℃ for 10 minutes, followed by reduction cleaning and drying to obtain wrinkle-resistant memory polyester printed fabric.

[0022] Example 3: Preparation of wrinkle-resistant memory polyester printed fabric: S1. Preparation of the skin layer polyester: S101. Sodium dimethyl isophthalate-5-sulfonate and triethylene glycol were added to a reaction vessel at a molar ratio of 1:2. Tetrabutyl titanate was added at 0.05% of the total mass of the reactants. The reaction was carried out at 180°C for 3 hours under nitrogen protection. The methanol generated was collected by fractionation column. After the reaction was completed, the unreacted triethylene glycol was removed by vacuum distillation to obtain the printing modifier. S102. By weight, 100 parts of terephthalic acid, 45 parts of ethylene glycol and 20 parts of printing modifier are esterified at 235°C for 2 hours. A catalyst is added and then polycondensed at 255°C under a vacuum of 100Pa for 3 hours to obtain the skin polyester. S2, Preparation of the core layer polyester: S201. 4,4'-Dithiodibenzoic acid and polytetrahydrofuran were added to a reaction vessel at a molar ratio of 1:2.1. Then, tetrabutyl titanate catalyst (0.05% of the total mass of the reactants) was added. After nitrogen purging three times, the temperature was raised to 185℃ and the reaction was maintained for 4 hours. During the reaction, the generated water was removed by intermittent vacuuming. When the acid value dropped below 5 mg KOH / g, the product was discharged while hot and cooled to room temperature to obtain an aromatic disulfide chain extender with a number average molecular weight of 2300 and a purity ≥95%. S202. By weight, 100 parts of terephthalic acid and 55 parts of ethylene glycol are subjected to esterification reaction at 230°C for 3 hours. A catalyst is added, the amount of which is 0.05% of the mass of terephthalic acid. 22 parts of aromatic disulfide chain extender and 0.1 parts of antioxidant are added. Polycondensation is carried out at 255°C under high vacuum for 3.5 hours to obtain the core layer polyester. S3, core-sheath composite spinning: After drying the polyester chips for the sheath and core layers, they are melt-extruded into the two screw extruders of a sheath-core composite spinning machine. The sheath spinning temperature is 255℃ and the core spinning temperature is 265℃. Composite spinning is carried out through a sheath-core composite spinneret. The melt viscosity ratio of the sheath to the core layer is controlled to be 1, the sheath-core mass ratio is 40:60, and the spinning speed is 1300m / min. After cooling, oiling, and winding, pre-oriented yarn is obtained, and then the sheath-core composite polyester fiber is obtained through stretching and deformation. S4. Weaving and Pre-dyeing Treatment: Core-sheath type composite polyester fibers are warped and woven to obtain greige fabric, which is then pre-dyed with disperse-cationic composite dyes. S5. Heat setting and printing: The pre-dyed fabric is heat-set at 155℃ for 70 seconds. Disperse-cationic composite dyes are then used to print on the heat-set fabric. The fabric is then steamed at 160℃ for 10 minutes, followed by reduction cleaning and drying to obtain wrinkle-resistant memory polyester printed fabric.

[0023] Comparative Example 1: Compared with Example 3, no printing modifier was added in Comparative Example 1, and the leather polyester was obtained by direct polycondensation of terephthalic acid and ethylene glycol, with other conditions remaining unchanged.

[0024] Comparative Example 2: Compared with Example 3, sodium dimethyl isophthalate-5-sulfonate was directly added in Comparative Example 2, and no printing modifier was prepared, while other conditions remained unchanged.

[0025] Comparative Example 3: Compared with Example 3, no aromatic disulfide chain extender was added in Comparative Example 3, while other conditions remained unchanged.

[0026] Comparative Example 4: Compared with Example 3, in Comparative Example 4, polytetrahydrofuran was replaced with polyethylene glycol in the preparation of the aromatic disulfide chain extender, while other conditions remained unchanged.

[0027] Comparative Example 5: Compared with Example 3, Comparative Example 5 used commercially available wrinkle-resistant memory polyester fabric (unprinted) and performed finishing processing according to the printing process of Example 3, with other conditions remaining unchanged.

[0028] Comparative Example 6: Compared with Example 3, Comparative Example 6 used core layer polyester single-component spinning without a skin layer, while other conditions remained unchanged.

[0029] Performance testing: The wrinkle-resistant memory polyester printed fabric described in this invention needs to undergo the following performance tests to comprehensively evaluate its wrinkle-resistant memory function, print color fastness, interfacial bonding strength, and wearability.

[0030] (1) Testing of basic mechanical properties of fibers and fabrics GB / T 3923.1-2013 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Strength and Elongation at Break (Strip Method)": Tests the breaking strength and elongation at break of fabrics to verify their mechanical strength.

[0031] (2) Anti-wrinkle performance test GB / T 3819-1997 "Determination of Crease Recovery of Textile Fabrics - Rapid Recovery Angle Method": Tests the crease recovery angle in the warp and weft directions, which directly reflects the wrinkle resistance; the larger the recovery angle, the better the wrinkle resistance.

[0032] (3) Shape memory performance test Test steps: Take three 5cm×5cm samples, heat them at 150℃ for 30s, fold them to 90°, keep them for 1min and then cool them to room temperature, and mark the initial crease angle; Immerse the sample in 40℃ warm water for 5 minutes, remove it and hang it naturally, and record the crease recovery angle after 30 minutes. Repeat the above folding-soaking-recovery cycle 50 times, and calculate the angle retention rate for each recovery.

[0033] Calculation formula: Shape memory retention rate (%) = (angle of nth recovery / initial recovery angle) × 100% (4) Printing color fastness test GB / T 3920-2008 "Textiles - Tests for color fastness to rubbing": Tests the color fastness to dry / wet rubbing to verify the rubbing resistance of printed patterns.

[0034] GB / T 3921-2008 "Textiles - Tests for color fastness to washing with soap": Tests color fastness to washing with soap and assesses the fading of printed colors after daily washing.

[0035] GB / T 3922-2013 "Textiles - Tests for color fastness to perspiration": Tests color fastness to perspiration, simulating the color fastness under human sweat conditions.

[0036] GB / T 8427-2019 "Textiles - Tests for color fastness to artificial light: Xenon arc": Tests color fastness to light and assesses the fading of printed materials after exposure to sunlight.

[0037] (5) Comfort and appearance test GB / T 9995-1997 "Determination of Moisture Content and Moisture Regain of Textile Materials - Oven Drying Method": Moisture regain is determined to evaluate the moisture absorption and wicking properties of fabrics.

[0038] GB / T 11048-2018 "Textiles - Physiological Comfort - Thermal and Moisture Resistance under Steady-State Conditions (Sweating and Warming Dummy Method)": Tests the breathability and moisture permeability of fabrics to assess wearing comfort.

[0039] (6) Disulfide bond retention rate test Test steps: Take a core layer polyester sample, dissolve it in tetrahydrofuran, filter out the insoluble matter, and determine the absorbance of the characteristic absorption peak of aromatic disulfide bonds (approximately 280 nm) using UV-Vis spectrophotometry. Calculate the disulfide bond content based on the standard curve. Test the disulfide bond content in samples after polycondensation, after steaming and color fixing, and after 50 water washes, and calculate the retention rate using the following formula: Disulfide bond retention rate (%) = (Disulfide bond content of treated sample / Disulfide bond content of initial sample) × 100%, Test conditions: UV-Vis spectrophotometer, wavelength scanning range 250-350 nm, slit width 2 nm, quartz cuvette optical path 1 cm. The standard curve was plotted using a series of concentration solutions prepared with 4,4'-dithiodibenzoic acid.

[0040] Figure 1 This is a schematic diagram of the structure of a core-sheath composite polyester fiber. The fiber has a concentric circular structure, with a light gray outer ring representing the sheath and a dark gray inner circle representing the core. The sheath is a modified polyester containing sulfonic acid groups, and the core is a polyester with block aromatic disulfide bonds. The sheath and core are based on homologous polyester, with a tight interface. This allows for functional partitioning, where the outer layer is suitable for printing and the inner layer carries wrinkle-resistant memory. Furthermore, the melt viscosity and melting point are matched to ensure spinning stability.

[0041] Figure 2 The process flow diagram for preparing wrinkle-resistant memory polyester printed fabric is as follows: First, a printing modifier and an aromatic disulfide bond chain extender are synthesized separately, and then the sheath polyester and the core polyester are prepared separately. Functional fibers are obtained by sheath-core composite spinning, followed by weaving and pre-dyeing treatment. Finally, the polyester fabric with high color fastness printing and wrinkle-resistant memory functions is obtained through heat setting and printing finishing.

[0042] Table 1. Physical and mechanical property data of the examples and comparative products. Group Fracture strength Elongation at break interfacial peel strength moisture regain unit N % N / cm % Example 1 725 25 5.3 2.1 Example 2 695 28 5.1 2.5 Example 3 745 23 5.6 2.3 Comparative Example 1 780 20 5.7 0.4 Comparative Example 2 660 24 4.9 2 Comparative Example 3 790 21 5.6 2.3 Comparative Example 4 675 30 4.3 2.2 Comparative Example 5 710 22 — 1.2 Comparative Example 6 720 25 — 0.4 Table 2. Data on wrinkle resistance and memory properties of the examples and comparative products. Group Wrinkle recovery angle (longitude + latitude) Shape memory retention rate (after 50 washes) Disulfide bond retention rate (after polycondensation) Disulfide bond retention rate (after evaporation) Disulfide bond retention rate (after 50 water washes) unit ° % % % % Example 1 271 87 97 95 86 Example 2 264 83 97 95 82 Example 3 283 93 98 96 91 Comparative Example 1 215 88 97 95 84 Comparative Example 2 245 76 89 84 68 Comparative Example 3 220 48 — — — Comparative Example 4 253 72 91 80 60 Comparative Example 5 225 65 — — — Comparative Example 6 280 92 98 96 91 Table 3. Color fastness data of printed products in the examples and comparative examples. Group Color fastness to rubbing (dry) Color fastness to rubbing (wet) Color fastness to soap washing Color fastness to perspiration Light fastness unit class class class class class Example 1 4-5 4 4-5 4-5 4 Example 2 5 4-5 5 5 4-5 Example 3 5 4-5 5 5 4-5 Comparative Example 1 2-3 2 2-3 2-3 3 Comparative Example 2 3-4 3 3-4 3-4 3-4 Comparative Example 3 5 4-5 5 5 4-5 Comparative Example 4 4-5 4 4-5 4-5 4 Comparative Example 5 3 2-3 3 3 3-4 Comparative Example 6 3-4 3 3-4 3-4 4 Data Analysis: Based on the data in Tables 1, 2, and 3, it was found that Example 3 exhibited the most balanced overall performance among the three examples. Test data showed a wrinkle recovery angle of 283° and a shape memory retention rate as high as 93%, thanks to the introduction of 22 aromatic disulfide bond extenders in the core layer. These aromatic disulfide bonds undergo reversible dynamic exchange at the heat-setting temperature, endowing the fabric with repeated shaping capabilities. Simultaneously, the addition of polytetrahydrofuran soft segments ensured a suitable memory trigger temperature, allowing the memory function to maintain a 91% retention rate after 50 washes. Regarding printing performance, the colorfastness to rubbing, washing, and perspiration all reached level 5 or 4-5, while the lightfastness was level 4-5. This is attributed to the sulfonic acid groups provided by the 20 printing modifiers in the leather layer, which provided ample dye beds for cationic dyes. The pre-padding dyeing process further ensured uniform dye anchoring. The interfacial peel strength of 5.6 N / cm indicated a strong bond between the leather and core. The moisture regain of 2.3% was significantly higher than ordinary polyester, indicating a marked improvement in skin-friendliness. It can be said that Example 3 achieves a balance between wrinkle-resistant memory, high color fastness printing, and good hand feel.

[0043] Based on Example 3, a series of comparative samples were obtained by adjusting the content of the leather printing modifier, the amount of the aromatic disulfide bond extender, the modification method, or the structural design. The performance differences of these samples precisely demonstrate the necessity of the various technical features of this invention. They will be analyzed one by one below: Compared to Example 3, Example 1 reduced the leather printing modifier from 20 parts to 15 parts, while keeping the aromatic disulfide chain extender unchanged at 22 parts. Test results showed that the wrinkle recovery angle of 271° was slightly lower than in Example 3, and the shape memory retention rate of 87% also decreased, but the overall memory performance remained good. Regarding printing color fastness, the color fastness to rubbing, washing, and perspiration was about half a grade lower than in Example 3, indicating that the reduced number of sulfonic acid groups resulted in insufficient dye sites, affecting the sufficiency of dye adsorption. The moisture regain of 2.1% also decreased accordingly. The interfacial peel strength of 5.3 N / cm was slightly lower but still within a reasonable range. This indicates that, under the premise that the core layer memory function is basically stable, the content of the leather modifier has a direct impact on printing performance; while 15 parts can meet the basic requirements, 20 parts is a better choice.

[0044] In Example 2, the leather layer printing modifier was 20 parts, while the aromatic disulfide chain extender in the core layer was reduced to 15 parts. Data shows that the color fastness to printing was comparable to or even slightly better than in Example 3, with resistance to rubbing, washing, and perspiration all reaching level 5, confirming the positive effect of sufficient sulfonic acid groups on printing performance. However, the shape memory performance declined significantly, with a wrinkle recovery angle of only 264°. After 50 washes, the shape memory retention rate dropped to 82%, and although the disulfide bond retention rate after polycondensation reached 97%, it was only 82% after 50 washes. This indicates that reducing the aromatic disulfide chain extender from 22 parts to 15 parts resulted in insufficient disulfide bond crosslinking density and impaired shape memory function. Simultaneously, the interfacial peel strength of 5.1 N / cm was also slightly lower than in Example 3. Example 2 illustrates that while pursuing high printing performance, shape memory function should not be excessively sacrificed; a balance must be struck between the two.

[0045] Compared to Example 3, Comparative Example 1 did not add any printing modifier. The polyester leather layer was obtained by direct reaction of terephthalic acid and ethylene glycol, making it a pure PET material. Test data showed that its printing performance deteriorated sharply, with rubbing fastness only grade 2-3 and washing fastness grade 2-3, far lower than the grade 5 level of Example 3. This is because the leather layer lacks sulfonic acid groups and cannot form ionic bonds with cationic dyes, relying solely on the physical adsorption of disperse dyes, resulting in extremely poor fastness. The moisture regain of 0.4% returned to the level of ordinary polyester, and its skin-friendly properties were lost. However, it is worth noting that its memory performance was slightly improved. Although the wrinkle recovery angle was only 215°, the breaking strength of 780N was the highest among all samples, and the interfacial peel strength of 5.7N / cm was also the highest. This indicates that the pure PET leather layer without modifier has high strength and a tighter bond with the core layer interface, but this comes at the cost of sacrificing printing performance, which is not worthwhile.

[0046] Compared to Example 3, Comparative Example 2 did not first prepare sodium dimethyl isophthalate-5-sulfonate (SIPM) as a printing modifier; instead, it was directly added to the polymerization system. Data showed that its wrinkle recovery angle was 245°, shape memory retention rate was 76%, and disulfide bond retention rate was only 89% after polycondensation, 84% after steaming, and 68% after 50 washes—all lower than in Example 3. This is because the sulfonic acid groups, directly integrated into the polyester backbone, disrupted the molecular chain regularity, and their polarity affected the microenvironment around the disulfide bonds, causing some disulfide bond damage during the high-temperature polycondensation stage. The printing color fastness grade of 3-4 was also lower than in Example 3, indicating that the directly added SIPM was unevenly distributed, and the sulfonic acid groups failed to fully function. This verifies the necessity of first preparing SIPM and triethylene glycol as a modifier.

[0047] Compared to Example 3, Comparative Example 3 did not contain an aromatic disulfide chain extender. Test results showed a wrinkle recovery angle of only 220°, a shape memory retention rate of 48%, and no data available for disulfide bond retention. This indicates that without disulfide bonds as dynamic crosslinking points, the fabric essentially loses its memory function, and the physical recovery of the polyether soft segments alone is far from sufficient to meet the memory requirements. However, its printing performance was comparable to Example 3, with abrasion resistance and soaping resistance both reaching level 5, a breaking strength of 790N (the highest), and a good interfacial peel strength of 5.6N / cm. This demonstrates that the memory function completely depends on disulfide bonds, while printing performance is independent of them; Comparative Example 3, from the opposite perspective, proves the core role of disulfide bonds.

[0048] Comparative Example 3, due to the retention of polytetrahydrofuran soft segments, has a slightly higher wrinkle recovery angle (220°) than Comparative Example 1 (215°) with a pure PET structure. However, due to the lack of disulfide bond dynamic crosslinking points, it basically loses its shape memory function. Although Comparative Example 1 has higher mechanical strength, it has shortcomings such as poor wrinkle recovery, low printing color fastness, and poor skin affinity. Both of these shortcomings jointly confirm the necessity of the synergistic design of sulfonic acid-based printing modification and disulfide bond memory modification in this invention.

[0049] Compared to Example 3, Comparative Example 4 replaced polytetrahydrofuran with polyethylene glycol in the preparation of the chain extender. Data showed that its wrinkle recovery angle was 253°, shape memory retention rate was 72%, disulfide bond retention rate was 91% after polycondensation, 80% after steaming, and only 60% after 50 water washes, and the interfacial peel strength of 4.3 N / cm was significantly lower than that of Example 3. This is because polyethylene glycol has poor thermal stability, partially decomposing to generate free radicals during polycondensation at 255°C, which attack disulfide bonds and cause damage. Simultaneously, polyethylene glycol's compatibility with PET is not as good as that of polytetrahydrofuran, resulting in uneven distribution of the chain extender in the polyester matrix and decreased interfacial bonding. This verifies the rationale for using polytetrahydrofuran as the soft segment.

[0050] Compared to Example 3, Comparative Example 5 used commercially available wrinkle-resistant memory polyester fabric for printing finishing. Test results showed a wrinkle recovery angle of 225° and a shape memory retention rate of 65%, lower than Example 3; the printing color fastness was only around grade 3, and the moisture regain was 1.2%. This is because commercially available wrinkle-resistant products mostly use finishing processes to impart memory function, which is not resistant to washing, and the memory function significantly diminishes after 50 washes; at the same time, they lack sulfonic acid group modification and may contain other small amounts of weakly hydrophilic groups, resulting in weak binding with cationic dyes, and limited printing fastness relying solely on conventional disperse dyes. This fully demonstrates the advantages of this invention, which modifies from the polymerization source, resulting in durable function and excellent printing performance.

[0051] Compared to Example 3, Comparative Example 6 used a single-component polyester core layer spinning method without a sheath structure. Data showed that its memory performance was comparable to Example 3, with a wrinkle recovery angle of 280°, a shape memory retention rate of 92%, and a disulfide bond retention rate of 98%, even slightly higher. However, its printing performance declined significantly, with a rubbing fastness of only 3-4 grades and a moisture regain of 0.4%, returning to the level of ordinary polyester. This is because without sheath sulfonic acid groups, the fabric surface lacks hydrophilicity and dye beds, making it difficult for dyes to fully adhere. This verifies the necessity of the core-sheath structure design; the memory function is undertaken by the core layer, and the printing function by the sheath layer; each layer fulfilling its specific function is essential to achieving both.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wrinkle-resistant memory polyester printed fabric, characterized in that, The fabric is made of core-sheath composite polyester fiber through weaving, pre-dyeing, heat setting, printing, and steaming for color fixing. The core-sheath composite polyester fiber includes a sheath layer and a core layer. The sheath layer is made of sheath polyester, which contains the following components by weight: 100 parts terephthalic acid, 40-50 parts ethylene glycol, and 15-25 parts printing modifier. The printing modifier is prepared by transesterification of sodium dimethyl isophthalate-5-sulfonate with triethylene glycol, and has a purity ≥98%. The core layer is made of core layer polyester, which contains the following components by weight: 100 parts terephthalic acid, 50-60 parts ethylene glycol, 15-30 parts aromatic disulfide chain extender, and 0.1-0.2 parts antioxidant. The melting point of the sheath polyester is 210-220℃, and the melting point of the core polyester is 245-255℃; at the spinning temperature, the melt viscosity ratio of the sheath to the core is 0.9-1.

1.

2. The wrinkle-resistant memory polyester printed fabric according to claim 1, characterized in that, The intrinsic viscosity of the outer polyester layer is 0.52-0.58 dL / g, the glass transition temperature is 55-60℃, and the sulfonic acid group content is 0.4-0.6 mmol / g; the intrinsic viscosity of the core polyester layer is 0.65-0.72 dL / g, the glass transition temperature is 75-85℃, and the disulfide bond content is 0.4-0.6 mmol / g.

3. A method for preparing the wrinkle-resistant memory functional polyester printed fabric according to any one of claims 1-2, characterized in that... Includes the following steps: S1. Preparation of the skin layer polyester: S101. Sodium dimethyl isophthalate-5-sulfonate and triethylene glycol are added to a reaction vessel at a molar ratio of 1:1.5-1:2.

5. Tetrabutyl titanate catalyst is added in an amount of 0.05-0.1% of the total mass of the reactants. The reaction is carried out at 170-190℃ for 3 hours under nitrogen protection. The methanol generated is collected through a fractionating column. After the reaction is completed, the unreacted triethylene glycol is removed by vacuum distillation to obtain the printing modifier. S102. Terephthalic acid, ethylene glycol and printing modifier are esterified at 230-240℃ for 2 hours. Tetrabutyl titanate is used as a catalyst. Then, polycondensation is carried out under high temperature and high vacuum to obtain the skin polyester. S2, Preparation of the core layer polyester: S201. Add 4,4'-dithiobenzoic acid and polytetrahydrofuran to a reactor at a molar ratio of 1:2.1, then add tetrabutyl titanate catalyst at a mass of 0.05-0.1% of the total reactants. After purging with nitrogen three times, heat to 180-190℃ and maintain the temperature for 4 hours. During the reaction, intermittently apply vacuum to remove the generated water. When the acid value drops below 5 mg KOH / g, discharge the material while hot and cool to room temperature to obtain an aromatic disulfide chain extender with a number average molecular weight of 2200-2500 and a purity ≥95%. S202. Terephthalic acid and ethylene glycol are esterified at 225-235℃ for 3 hours, with tetrabutyl titanate as catalyst, the amount of which is 0.03-0.06% of the mass of terephthalic acid. Aromatic disulfide chain extender and antioxidant are added and polycondensed under high vacuum at 250-260℃ for 3.5 hours to obtain core layer polyester. S3, core-sheath composite spinning: After drying the polyester chips of the sheath and core layers, they are melt-extruded into the two screw extruders of the sheath-core composite spinning machine. The composite spinning is carried out through the sheath-core composite spinneret. The melt viscosity ratio of the sheath layer to the core layer is controlled to be 0.9-1.

1. After cooling, oiling, and winding, pre-oriented yarn is obtained, and then the sheath-core composite polyester fiber is obtained by stretching and deformation. S4. Weaving and Pre-dyeing Treatment: Core-sheath type composite polyester fibers are warped and woven to obtain greige fabric, which is then pre-dyed with disperse-cationic composite dyes. S5. Heat setting and printing: The pre-dyed fabric is heat-set, and then printed with disperse-cationic composite dyes. The fabric is then steamed and fixed at 155-160℃, followed by reduction cleaning and drying to obtain wrinkle-resistant memory polyester printed fabric.

4. The method for preparing a wrinkle-resistant memory function polyester printed fabric according to claim 3, characterized in that, The amount of tetrabutyl titanate added in S102 is 0.02-0.05% of the mass of terephthalic acid, and the polycondensation conditions are: polycondensation temperature 250-260℃, vacuum degree 100Pa, and time 3h.

5. The method for preparing a wrinkle-resistant memory polyester printed fabric according to claim 3, characterized in that, The spinning temperature of the sheath layer in S3 is 250-260℃, the spinning temperature of the core layer is 260-270℃, the sheath-core mass ratio is 35-40:60-65, the spinning speed is 1200-1400m / min, the draw ratio is 1.6-1.8, and the draw temperature is 90-110℃.

6. The method for preparing a wrinkle-resistant memory function polyester printed fabric according to claim 3, characterized in that, The heat setting temperature in S5 is 150-160℃, and the time is 60-80 seconds; the evaporation and color fixing temperature is 155-160℃, and the time is 9-11 minutes.

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