High-performance easy-to-dye cool-feeling fiber and preparation method thereof, and low-temperature dyeing process

Abstract

The application relates to the field of textiles, and particularly discloses a high-performance easy-to-dye cool-feeling fiber, a preparation method thereof, and a low-temperature dyeing process. The high-performance easy-to-dye cool-feeling fiber comprises the following raw materials in parts by mass: 40-55 parts of terephthalic acid, 18-25 parts of ethylene glycol, 1-5 parts of sodium m-phthalic acid-5-sulfonate, 1-5 parts of polyester polyol grafted cool-feeling filler, 0.01-0.05 parts of a catalyst, 0.01-0.10 parts of an anti-crosslinking agent, and 0.01-0.04 parts of an antioxidant. The fiber prepared by the application has stable cool feeling and color fastness.

Description

Technical Field

[0001] This application relates to the textile field, and more specifically, to a high-performance, easily dyeable, cool-feeling fiber, its preparation method, and a low-temperature dyeing process. Background Technology

[0002] Polyester cooling fiber, with its cooling properties, can quickly conduct heat from the human body and lower the skin surface temperature, making it a core raw material for summer clothing, infant and toddler home textiles, and outdoor protective fabrics. Market demand is increasing year by year, and it has both practical and economic value.

[0003] Currently, the core technological contradiction facing the development of polyester cooling fibers is the mutual constraint between cooling stability and color fastness: the cooling function is mainly achieved by adding inorganic cooling fillers, while the dyeing performance needs to be obtained through fiber modification to achieve cationic dyeability. The two are inherently conflicting in terms of mechanism of action and process compatibility. Cooling agents are mostly inorganic fillers, which have poor compatibility with polyester matrix and are prone to agglomeration and shedding, resulting in rapid decay of cooling performance after washing. On the other hand, the high-temperature dyeing process required for cationic dyeability modification will destroy the structural integrity of cooling fillers, further reducing cooling stability. At the same time, cooling agents and dyes easily compete for binding sites, further leading to a decrease in color fastness.

[0004] In existing technologies, to achieve cationic dyeability of polyester fibers, the common approach is to introduce a third monomer, sodium isophthalic acid-5-sulfonate (SIPE). By introducing sulfonic acid groups into the polyester molecular chain, ionic binding sites are provided for cationic dyes, effectively reducing dyeing temperature and improving dyeing uniformity. However, this method has significant drawbacks and directly affects cooling stability and colorfastness: sulfonic acid groups are highly polar and easily form ionic aggregates between molecules, leading to deterioration of the rheological properties of the polyester melt and problems such as yarn breakage and uneven filaments during spinning. Simultaneously, sulfonic acid group aggregation results in uneven distribution of dye binding sites, increased surface floating color, and lower rubbing and washing fastness. Furthermore, aggregated sulfonic acid groups exacerbate the agglomeration of inorganic cooling fillers, disrupting cooling heat conduction channels, leading to decreased cooling stability and a significant reduction in cooling retention after washing.

[0005] To address the aforementioned shortcomings, existing technologies have proposed several improvement solutions: First, modifying the cooling filler with a silane coupling agent to improve its compatibility with the polyester matrix. However, silane modification suffers from weak binding force, the cooling agent is still prone to detachment, and it competes with sulfonic acid groups for binding sites, failing to fundamentally solve the color fastness problem. Second, adding a fourth monomer such as polyethylene glycol to reduce the crystallinity of the polyester and assist in improving dyeing and compatibility, but this leads to a decrease in fiber mechanical properties. Third, optimizing dyeing process parameters, such as lowering the dyeing temperature or adjusting the dye bath system, is difficult to balance dyeing rate, levelness, and cooling stability, failing to overcome the core contradiction.

[0006] In summary, current technologies have not effectively resolved the core conflict between cooling stability and colorfastness in polyester cooling fibers, and suffer from problems such as poor melt rheology, insufficient mechanical properties, and poor industrial adaptability, failing to meet the application requirements of high-end textile products. Therefore, developing a polyester cooling fiber modification technology that can effectively disperse sulfonic acid groups, achieve a strong bond with cooling agents, and balance cooling stability, colorfastness, and industrial mass production has become a pressing technical challenge for the industry, possessing significant research value, industrial application value, and market prospects. Summary of the Invention

[0007] In order to prepare a polyester fiber that has both stable cooling sensation and color fastness, this application provides a high-performance, easily dyeable cooling fiber, its preparation method, and a low-temperature dyeing process.

[0008] In a first aspect, this application provides a high-performance, easily dyeable, cooling fiber, employing the following technical solution: comprising the following raw materials in parts by weight: 40-55 parts terephthalic acid, 18-25 parts ethylene glycol, 1-5 parts sodium isophthalate-5-sulfonate, 1-5 parts polyester polyol grafted cooling filler, 0.01-0.05 parts catalyst, 0.01-0.10 parts anti-crosslinking agent, and 0.01-0.04 parts antioxidant.

[0009] This application utilizes classic PET and CDP base raw materials, and ensures sufficient transesterification and polycondensation reactions under certain ratio settings to form a high molecular weight polyester backbone, providing basic mechanical properties for the fiber. Sodium isophthalic acid-5-sulfonate introduces sulfonic acid groups to provide ion binding sites for cationic dyes. Under certain mass settings, there will be no insufficient ion sites, resulting in low dyeing rate and poor color fastness, nor will there be excessive sulfonic acid group content, which would lead to a sharp increase in ion aggregation effect, a sudden increase in melt viscosity, and difficulty in spinning. At the same time, excessive destruction of molecular chain regularity would reduce the mechanical properties of the fiber. A certain mass of polyester polyol grafted cooling filler is added as a core functional modifier to replace the fourth monomer PEG, traditional cooling agent, and rheology modifier of traditional ECDP. This achieves synergistic effects of PEG-like softening, sulfonic acid group dispersion, rheology regulation, cooling function, and dyeing. At the same time, compared with traditional ECDP, it solves the problems of poor compatibility and performance imbalance caused by multi-component compounding, and has suitable flexibility and steric hindrance. Catalysts, anti-crosslinking agents, and antioxidants are used to ensure the efficiency of polycondensation reaction, inhibit high-temperature crosslinking degradation of molecular chains, and prevent oxidative degradation of polyester segments, respectively, providing a stable reaction environment for fiber preparation. The resulting fibers combine the mechanical properties of traditional CDP, the low-temperature dyeing characteristics of ECDP, and superior cooling stability and color fastness, exhibiting excellent overall performance. This invention applies polyester polyol grafted with cooling fillers to the modification of cationic dyeable polyester, abandoning the traditional multi-component compounding approach and achieving functional integration of multiple components with a single modifier. Furthermore, through extensive experiments, the critical optimal mass fraction range of each raw material was determined. Compared to simply increasing SIPE content to improve dyeability, this invention combines cooling functional modification with CDP molecular structure modification from the source, solving the core contradictions in existing technologies such as easy shedding of cooling agents and competition for dye sites.

[0010] Preferably, the polyester polyol-grafted cooling filler includes the following preparation steps: dispersing the cooling filler in propylene glycol, adding polyester polyol, adipic acid, and p-toluenesulfonic acid, heating and stirring to react, desolventizing under reduced pressure, and drying to obtain the polyester polyol-grafted cooling filler.

[0011] The preparation steps of polyester polyol-grafted cooling fillers revolve around ensuring the homologous compatibility of the modifier and the CDP system, achieving a strong bond between the cooling filler and the polyester polyol, and adapting to industrial production. It abandons traditional heterogeneous modification methods such as silanes and dopamines, and instead employs esterification, a reaction homologous to CDP transesterification and polycondensation, to achieve grafting. This ensures no interfacial separation or structural defects between the modifier and the polyester matrix, resulting in minimal impurity residue. The preparation steps are simple, requiring no special equipment and can directly utilize existing polyester modifier production equipment, leading to low industrialization costs and easy scale-up. Furthermore, the covalent bonding of the filler into the polyester backbone may form a unique microstructure, thereby simultaneously achieving a synergistic effect of uniform dye binding sites and stable cooling thermal conduction channels, resulting in improved product performance.

[0012] Preferably, the polyester polyols include ordinary polyester polyols and hyperbranched polyester polyols.

[0013] Based on the structure-property differences of polyester polyols, a balance is achieved between "steric hindrance dispersion of sulfonic acid groups" and "reduced crystallinity of flexible segments" through specific selection, meeting the requirements for high-performance fibers. Sufficient three-dimensional steric hindrance can effectively physically separate CDP molecular chains, preventing the aggregation of sulfonic acid group ions from the source. At the same time, hydroxyl groups can significantly increase the esterification grafting rate with cooling fillers and provide sufficient sites for polycondensation reactions with CDP prepolymers, ensuring a strong covalent bond between the modifier and CDP molecular chains. Long polyester segments can more efficiently interpenetrate between CDP molecular chains, breaking the rigid and regular structure of the molecular chains, reducing fiber crystallinity, while larger molecular weights can further reduce melt friction, improve rheological control effects, and prevent a sudden increase in viscosity during spinning.

[0014] Preferably, the mass ratio of sodium isophthalate-5-sulfonate and polyester polyol grafted cooling filler is (2-3):4.

[0015] At this time, the polyester polyol grafted cool-feeling filler has a good reinforcing effect on the fiber and a good ion aggregation and dispersion effect on the sulfonic acid groups, and is also easy to dye.

[0016] Preferably, the mesh size of the cooling filler is 800-2000 mesh.

[0017] Preferably, the mass ratio of ethylene glycol to polyester polyol grafted cooling filler is (5-6):1.

[0018] Under the aforementioned mass ratio, sufficient polycondensation reaction, stable melt rheology, and uniform dispersion of the cooling filler are achieved. Ethylene glycol is not only the core monomer for CDP polycondensation, providing terminal hydroxyl groups to the polyester molecular chain to ensure sufficient transesterification and polycondensation reactions, but it also acts as a melt viscosity modifier, diluting the CDP melt, reducing internal friction, and optimizing rheological properties. Meanwhile, the terminal hydroxyl groups on the surface of the hyperbranched polyester polyol-grafted cooling filler may undergo esterification with the carboxyl groups of terephthalic acid, thus participating in subsequent polycondensation reactions and achieving partial substitution. On one hand, the terminal hydroxyl groups of the modifier and the hydroxyl groups of ethylene glycol synergistically participate in esterification and polycondensation, ensuring the formation of the polyester backbone while covalently incorporating the modifier into the CDP molecular chain, preventing the cooling filler from agglomerating. On the other hand, the steric hindrance of the hyperbranched structure synergistically with the flexibility of the polyester segments, simultaneously achieving sulfonic acid group dispersion, crystallinity control, and melt rheological optimization, balancing the function of the modifier and the properties of the matrix. This further enhances the stability of the cooling filler, optimizes the rheological properties of the melt, and disperses the sulfonic acid groups. It improves spinning stability and is suitable for industrial production. The filaments are less prone to stretching and breakage during spinning, and the resulting fibers have no core-sheath structure, exhibiting excellent dimensional stability. The cooling filler forms good thermal conductivity channels.

[0019] Preferably, the mass ratio of ordinary polyester polyol to hyperbranched polyester polyol is 1:(2-3).

[0020] This ratio is limited based on the structure-property differences between the two polyester polyols. The core is to achieve a triple balance of "steric hindrance dispersion of sulfonic acid groups, reduction of crystallinity in flexible segments, and maintenance of mechanical strength," while also taking into account the performance requirements of different downstream applications, thus achieving customized control of fiber performance. Among them, the hyperbranched polyester polyol, as the core of sulfonic acid group dispersion, provides sufficient three-dimensional steric hindrance, physically separating the CDP molecular chains and completely preventing the aggregation of sulfonic acid group ions. At the same time, its terminal hydroxyl groups can ensure a high grafting rate with the cooling filler and a strong covalent bond with the CDP prepolymer, providing a foundation for cooling stability and dyeing fastness. The ordinary polyester polyol, as the core of flexibility enhancement, allows for precise control of the crystallinity and melt flexibility of CDP by adjusting its dosage.

[0021] Secondly, this application provides a method for preparing high-performance, easily dyeable, cooling fibers, comprising the following preparation steps: weighing raw materials according to mass parts, mixing them evenly, heating under nitrogen protection, maintaining the temperature for reaction, raising the temperature, reducing the pressure for maintaining the temperature for reaction, extruding and spinning, stretching and shaping, to obtain high-performance, easily dyeable, cooling fibers.

[0022] Preferably, the temperature in the first zone of the extrusion spinning process is 270±1℃, the temperature in the second zone is 273±1℃, the temperature in the third zone is 275±1℃, and the shear rate is 940-960s⁻¹.

[0023] This parameter is limited based on the rheological properties of the CDP melt after polyester polyol modification and the ionic aggregation characteristics of sulfonic acid groups. It is key to ensuring spinning stability, inhibiting sulfonic acid group aggregation, and protecting the structure of the modifier. The three-zone gradient heating design effectively avoids localized overheating of the melt. Since the temperature sensitivity of CDP melt is significantly increased after modification with polyester polyol, localized overheating can lead to sulfonic acid group aggregation, polyester chain segment breakage, and a sudden increase in melt viscosity, resulting in problems such as spinning breakage and uneven filaments. Gradient heating allows the melt to be heated gradually, resulting in a uniform temperature distribution without localized hot spots. Simultaneously, at this shear rate, CDP melt, as a pseudoplastic non-Newtonian fluid, experiences a decrease in melt viscosity with increased shear rate. The shear rate in this zone allows the melt viscosity to be reduced to the optimal spinning viscosity, while effectively weakening the ionic aggregation effect of sulfonic acid groups. If the shear rate is too low, the shear thinning effect is insufficient, resulting in excessively high melt viscosity, high spinning resistance, and the inability to effectively suppress sulfonic acid group aggregation. Furthermore, it can damage the hyperbranched structure of the polyester polyol, leading to excessive shear degradation of the molecular chains and a decline in fiber mechanical properties. The resulting fibers exhibit no adhesion or breakage, have a uniform internal structure, and lack a core-sheath structure and micropores. The cooling filler does not exhibit shear agglomeration and is easily dyed.

[0024] Preferably, the filaments are cooled by cold air at 25±3℃ during the spinning process, with a wind speed of 0.8-1.0m / s.

[0025] Under these parameters, the cooling filler is uniformly dispersed in the fiber without segregation or agglomeration, forming a continuous heat-conducting channel, without hot or cold spots, resulting in a consistent cooling sensation, uniform filament cooling, no sticking or swaying, low spinning breakage rate, and excellent spinning stability.

[0026] Thirdly, this application provides a low-temperature dyeing process for high-performance, easily dyeable, cool-feeling fibers, including the following dyeing steps: fiber is placed in a dye bath, the temperature is increased to 55-65℃ at a rate of 1-3℃ / min, the temperature is maintained for 25-35min, the fiber is washed with water, and the temperature is heated to 100-120℃ for 1-3min.

[0027] This process is designed based on the lower crystallinity, higher amorphous region, and uniformly distributed sulfonic acid groups of CDP fibers modified with polyester polyol. The core is to solve the problems of high temperature damage to the cooling sensation, low dyeing rate, and poor leveling of traditional CDP medium-temperature dyeing, and to achieve the synergistic effect of dyeing without damaging the cooling sensation and the cooling sensation not affecting the dyeing. In this dyeing process, the slow heating rate design effectively avoids the concentration and adsorption of dye on the fiber surface. Although the polar sites on the surface of CDP fibers modified with polyester polyol are evenly distributed, there are still slight differences in site density. Rapid heating will cause the dye to be rapidly adsorbed at high-density sites, forming color spots and color differences. Slow heating allows the dye molecules to gradually diffuse into the fiber interior, achieving uniform dyeing. Within the low-temperature dyeing temperature range, the diffusion rate of dye molecules matches the molecular chain movement rate of the amorphous region of the fiber. The dye can quickly diffuse into the fiber interior and fully combine with the sulfonic acid groups and the terminal hydroxyl groups of the polyester polyol. At the same time, this temperature is much lower than the medium-temperature dyeing temperature of traditional CDP, which can completely avoid the damage of high temperature to the cooling filler, ensure high retention of the cooling function, and avoid low dyeing rate due to insufficient heat preservation, while also avoiding increased production costs due to excessive heat preservation. The low-temperature setting step after washing can effectively remove the floating color on the fiber surface, while making the fiber structure more stable and improving dimensional stability. It also avoids the thermal shrinkage of polyester polyol segments on the surface of the cooling filler, protects the thermally conductive sites, and ensures that the cooling efficiency does not decrease.

[0028] Preferably, the dye bath pH is 4.0-5.0, and includes 1-5% owf of cationic dye and 0.1-0.5 g / L of leveling agent.

[0029] To ensure efficient binding of dyes and sulfonic acid groups, improve dyeing levelness and color fastness, and protect fiber and dye properties, the dye bath pH is controlled at 4.0-5.0. An acetate-sodium acetate buffer system is preferred, as it stabilizes the dissociation state of the sulfonic acid groups. Under these weakly acidic conditions, the sulfonic acid groups can completely dissociate, providing sufficient anionic binding sites for cationic dyes and ensuring efficient ionic bonding. If pH < 4, the sulfonic acid groups will ionize to form -SO3H, losing their binding ability with cationic dyes and resulting in a significant decrease in dye uptake. If pH > 5, the polyester molecular chain will undergo slight hydrolysis, leading to a decrease in fiber mechanical properties. Simultaneously, cationic dyes are prone to hydrolysis and inactivation, affecting dyeing results. The application of the buffer system effectively avoids pH fluctuations in the dye bath caused by dye uptake during the dyeing process, ensuring that the sulfonic acid groups are always in an optimal dissociation state. The concentration of the cationic dye is perfectly matched to the number of effective sulfonic acid sites in the CDP fiber modified with polyester polyol. Since the number of effective sulfonic acid sites in the modified fiber is significantly increased compared to traditional CDP, this concentration range ensures sufficient dye application and vibrant fiber color, while avoiding excessive dye application that leads to increased surface floating color and decreased color fastness. Furthermore, the acetate-sodium acetate buffer system is organically combined with appropriate dye and leveling agent concentrations. Based on the sulfonic acid group dissociation characteristics of the CDP fiber modified with polyester polyol, a targeted design was implemented, achieving highly efficient binding of the dye and sulfonic acid groups. This overcomes the technical limitations of existing technologies, such as lack of dye bath pH buffering, excessively high or low dye concentrations, and unreasonable leveling agent selection.

[0030] In summary, this application effectively resolves the core contradiction between the cooling stability and colorfastness of existing polyester cooling fibers. By covalently grafting cooling fillers onto polyester polyols, it prevents the aggregation and shedding of cooling agents, thus improving the durability of the cooling sensation. Simultaneously, this modifier disperses sulfonic acid groups, preventing ion aggregation, optimizing melt rheological properties, reducing spinning breakage rate, and improving spinning stability. Furthermore, it enables low-temperature dyeing, balancing dye uptake and leveling, and improving colorfastness to a high level according to national standards without compromising the cooling function. This invention requires no additional specialized equipment, is suitable for industrial mass production, simplifies the formulation, and balances fiber mechanical properties and flexibility, meeting the needs of high-end textile products. It possesses significant industrial application value and market prospects, driving the upgrade of polyester cooling fibers towards high performance and integrated functionality. Detailed Implementation

[0031] To further aid in understanding the technical solution of this invention, several specific implementation examples are provided below to describe the technical solution of this invention in more detail. All of these described embodiments are only some embodiments of this invention, and not all of them. The following specific embodiments can be combined with each other. The same or similar concepts or processes may not be described again in some embodiments. Unless otherwise specified, the reaction devices, monomer compounds and other materials involved in the following embodiments are commercially available.

[0032] The following examples are further illustrations of the present invention, but the present invention is not limited thereto.

[0033] Cooling filler was purchased from Erping Minerals (1250 mesh jade powder); ordinary polyester polyol was purchased from Huide Technology (HDPOL-4420LS), with a hydroxyl value of 54-58 and a molecular weight of 2000; hyperbranched polyester polyol was purchased from BASF (Basonol HPE1170B); and leveling agent was purchased from Nantong Huzhuo Chemical Co., Ltd. (nonionic leveling agent AN).

[0034] Preparation Example Preparation Example 1: Cooling Filler Grafted with Ordinary Polyester Polyol Raw material weighing: 100g cooling filler, 300ml propylene glycol, 80g ordinary polyester polyol, 15g adipic acid, and 2g p-toluenesulfonic acid.

[0035] Preparation steps: Disperse the cooling filler in propylene glycol, stir at 800 r / min for 30 min, add the remaining raw materials, heat to 150℃ at 1.5℃ / min, stir at 800 r / min for 4 h, then desolvate at -0.09 MPa under reduced pressure at 160℃ for 2 h, and finally vacuum dry at 105℃ for 6 h, pulverize and pass through a 300 mesh sieve to obtain ordinary polyester polyol grafted cooling filler.

[0036] Preparation Example 2: Hyperbranched Polyester Polyol Grafted Cooling Filler Raw material weighing: 100g cooling filler, 300ml propylene glycol, 80g hyperbranched polyester polyol, 15g adipic acid, and 2g p-toluenesulfonic acid.

[0037] Preparation steps: Disperse the cooling filler in propylene glycol, stir at 800 r / min for 30 min, add the remaining raw materials, heat to 150℃ at 1.5℃ / min, stir at 800 r / min for 4 h, then desolvate at -0.09 MPa under reduced pressure at 160℃ for 2 h, and finally vacuum dry at 105℃ for 6 h, pulverize and pass through a 300 mesh sieve to obtain the hyperbranched polyester polyol grafted cooling filler. Example Example 1

[0038] Fiber raw material weighing: 48 parts terephthalic acid, 22 parts ethylene glycol, 2.5 parts sodium isophthalate-5-sulfonate (SIPE), 4 parts of the hyperbranched polyester polyol grafted cooling filler obtained in Preparation Example 2, 0.03 parts of catalyst Sb2O3, 0.05 parts of anti-crosslinking agent TPP, and 0.02 parts of antioxidant 1010.

[0039] Preparation method: Terephthalic acid, ethylene glycol, and sodium isophthalate-5-sulfonate were mixed evenly and heated to 222℃ under nitrogen protection and held for 2.5h; the remaining raw materials were added, the temperature was raised to 273℃, the pressure was reduced to 40Pa, and held for 4h; twin-screw extruder was used with zone 1 at 270℃, zone 2 at 273℃, and zone 3 at 275℃, shear rate at 950s⁻¹, 0.8mm large-diameter spinneret was selected, the spinneret temperature was 274℃, and the extrusion rate was 3.7g / min; the filaments were cooled with 25℃ cold air at a speed of 0.9m / s, hot-stretched 3.3 times at 89℃, and set at 125℃ for 5min to obtain high-performance, easy-dyeing, cool-feeling fiber.

[0040] Low-temperature dyeing process: The high-performance, easy-dyeing, cool-feeling fiber is added to a pretreatment solution containing 2 g / L scouring agent and 1 g / L soda ash, scourted at 90℃ for 25 min, washed with water until neutral, and then a pH 4.5 acetate-sodium acetate buffer system dye bath is prepared, with 3% owf of cationic red X-GRL and 0.3 g / L leveling agent in the dye bath; the fiber is placed in the dye bath, the temperature is increased to 60℃ at 2℃ / min, and held for 30 min; washed twice with water, and set at 110℃ for 3 min. Example 2

[0041] The only difference between this embodiment and Embodiment 1 is that: Fiber raw material weighing: 48 parts terephthalic acid, 18 parts ethylene glycol, 2.5 parts sodium isophthalate-5-sulfonate (SIPE), 4 parts of the hyperbranched polyester polyol grafted cooling filler obtained in Preparation Example 2, 0.03 parts catalyst Sb2O3, 0.05 parts anti-crosslinking agent TPP, and 0.02 parts antioxidant 1010. Example 3

[0042] The only difference between this embodiment and Embodiment 1 is that: Fiber raw material weighing: 48 parts terephthalic acid, 25 parts ethylene glycol, 2.5 parts sodium isophthalate-5-sulfonate (SIPE), 4 parts of the hyperbranched polyester polyol grafted cooling filler obtained in Preparation Example 2, 0.03 parts of catalyst Sb2O3, 0.05 parts of anti-crosslinking agent TPP, and 0.02 parts of antioxidant 1010. Example 4

[0043] The only difference between this embodiment and Embodiment 1 is that: The fiber raw materials were weighed as follows: 48 parts terephthalic acid, 22 parts ethylene glycol, 5 parts sodium isophthalate-5-sulfonate (SIPE), 4 parts of the hyperbranched polyester polyol grafted cool-feeling filler prepared in Preparation Example 2, 0.03 parts of catalyst Sb2O3, 0.05 parts of anti-crosslinking agent TPP, and 0.02 parts of antioxidant 1010. Example 5

[0044] The only difference between this embodiment and Embodiment 1 is that: Fiber raw material weighing: 48 parts terephthalic acid, 22 parts ethylene glycol, 1 part sodium isophthalate-5-sulfonate (SIPE), 4 parts of the hyperbranched polyester polyol grafted cooling filler obtained in Preparation Example 2, 0.03 parts of catalyst Sb2O3, 0.05 parts of anti-crosslinking agent TPP, and 0.02 parts of antioxidant 1010. Example 6

[0045] The only difference between this embodiment and Embodiment 1 is that: Fiber raw material weighing: 48 parts terephthalic acid, 22 parts ethylene glycol, 2.5 parts sodium isophthalate-5-sulfonate (SIPE), 2 parts ordinary polyester polyol grafted cooling filler prepared in Preparation Example 1, 2 parts hyperbranched polyester polyol grafted cooling filler prepared in Preparation Example 2, 0.03 parts catalyst Sb2O3, 0.05 parts anti-crosslinking agent TPP, and 0.02 parts antioxidant 1010. Example 7

[0046] The only difference between this embodiment and Embodiment 1 is that: Fiber raw material weighing: 48 parts terephthalic acid, 22 parts ethylene glycol, 2.5 parts sodium isophthalate-5-sulfonate (SIPE), 1 part ordinary polyester polyol grafted cooling filler prepared in Preparation Example 1, 3 parts hyperbranched polyester polyol grafted cooling filler prepared in Preparation Example 2, 0.03 parts catalyst Sb2O3, 0.05 parts anti-crosslinking agent TPP, and 0.02 parts antioxidant 1010. Example 8

[0047] The only difference between this embodiment and Embodiment 1 is that: Preparation method: Terephthalic acid, ethylene glycol, and sodium isophthalate-5-sulfonate were mixed evenly and heated to 222℃ under nitrogen protection and held for 2.5h; the remaining raw materials were added, the temperature was raised to 273℃, the pressure was reduced to 40Pa, and held for 4h; twin-screw extruder was used with zone 1 at 270℃, zone 2 at 273℃, and zone 3 at 275℃, shear rate at 700s⁻¹, 0.8mm large-diameter spinneret was selected, the spinneret temperature was 274℃, and the extrusion rate was 3.7g / min; the filaments were cooled with 25℃ cold air at a speed of 0.9m / s, hot-stretched 3.3 times at 89℃, and set at 125℃ for 5min to obtain high-performance, easy-dyeing, cool-feeling fiber. Example 9

[0048] The only difference between this embodiment and Embodiment 1 is that: Low-temperature dyeing process: The high-performance, easy-dyeing, cool-feeling fiber is added to a pretreatment solution containing 2 g / L scouring agent and 1 g / L soda ash, scourted at 90℃ for 25 min, washed with water until neutral, and then a pH 4.5 acetate-sodium acetate buffer system dye bath is prepared, with 3% owf of cationic red X-GRL and 0.1 g / L leveling agent in the dye bath; the fiber is placed in the dye bath, the temperature is increased to 60℃ at 2℃ / min, and held for 30 min; washed twice with water, and set at 110℃ for 3 min.

[0049] Comparative Example Comparative Example 1 Fiber raw material weighing: 48 parts terephthalic acid, 22 parts ethylene glycol, 2.5 parts sodium isophthalate-5-sulfonate (SIPE), 2 parts polyvinyl alcohol, 4 parts cooling filler, 0.03 parts catalyst Sb2O3, 0.05 parts anti-crosslinking agent TPP, and 0.02 parts antioxidant 1010.

[0050] Preparation method: Terephthalic acid, ethylene glycol, and sodium isophthalate-5-sulfonate were mixed evenly and heated to 222℃ under nitrogen protection and held for 2.5h; the remaining raw materials were added, the temperature was raised to 273℃, the pressure was reduced to 40Pa, and held for 4h; twin-screw extruder was used with zone 1 at 270℃, zone 2 at 273℃, and zone 3 at 275℃, shear rate at 950s⁻¹, 0.8mm large-diameter spinneret was selected, the spinneret temperature was 274℃, and the extrusion rate was 3.7g / min; the filaments were cooled with 25℃ cold air at a speed of 0.9m / s, hot-stretched 3.3 times at 89℃, and set at 125℃ for 5min to obtain high-performance, easy-dyeing, cool-feeling fiber.

[0051] Low-temperature dyeing process: The high-performance, easy-dyeing, cool-feeling fiber is added to a pretreatment solution containing 2 g / L scouring agent and 1 g / L soda ash, scourted at 90℃ for 25 min, washed with water until neutral, and then a pH 4.5 acetate-sodium acetate buffer system dye bath is prepared, with 3% owf of cationic red X-GRL and 0.3 g / L leveling agent in the dye bath; the fiber is placed in the dye bath, the temperature is increased to 60℃ at 2℃ / min, and held for 30 min; washed twice with water, and set at 110℃ for 3 min.

[0052] Performance testing Test 1: Color fastness to washing was tested according to GB / T5713.

[0053] Test 2: The contact cooling coefficient was tested in accordance with GB / T14344 "Test and Evaluation of Instantaneous Cooling Performance of Textiles".

[0054] Test 3: The prepared sample was subjected to 50 quick washes in a commercially available drum washing machine. Test 2 was repeated to detect the contact cooling coefficient. The cooling coefficient retention rate was calculated as follows: Cooling coefficient retention rate = Contact cooling coefficient / Contact cooling coefficient × 100%.

[0055] Test 4: Test the breaking strength according to GB / T-14337 "Test Method for Tensile Properties of Filaments".

[0056] The test data are summarized in Table 1.

[0057] Table 1

[0058] Based on the embodiments and comparative examples, and Table 1, the causes of performance parameters were analyzed: Example 2: Insufficient supply of ethylene glycol terminal hydroxyl groups resulted in high melt viscosity, increased internal friction within the melt, decreased dispersion of sulfonic acid groups, uneven distribution of dye binding sites, and a slight decrease in color fastness. The cool-feeling filler participated in polycondensation, thus slightly reducing the retention rate and causing a slight decrease in fiber breaking strength.

[0059] Example 3: Excess ethylene glycol provides better melt rheology control, reduces internal melt friction, allows for more complete steric hindrance of hyperbranched polyester polyols, more uniform dispersion of sulfonic acid groups, stronger dye ionic bonding, and good color fastness. The cooling filler is more uniformly dispersed in the low-viscosity melt, and the thermal conduction channels are continuous. However, the increase in ethylene glycol and the decrease in the proportion of hyperbranched polyester polyols reduce the orientation of molecular chains and the reinforcement of fibers during spinning, resulting in a slight decrease in fiber breaking strength. The cooling retention rate remains basically unchanged due to the grafting structure.

[0060] In Example 4, the increased content of sulfonic acid groups, coupled with insufficient grafting of cooling filler onto polyester polyol, resulted in inadequate dispersion of the sulfonic acid groups, leading to severe ion aggregation. This significantly reduced and unevenly distributed effective dye binding sites, increased surface floating color, and a marked decrease in color fastness. The aggregated sulfonic acid groups formed electrostatic adsorption with the surface groups of the cooling filler, slightly disrupting the uniform dispersion of the filler and affecting the continuity of the thermal conductivity channels. This resulted in a slight decrease in Q-max and a minor reduction in retention rate. Excessive sulfonic acid groups severely damaged the regularity of the polyester molecular chains, weakening the intermolecular forces and reducing the breaking strength.

[0061] Example 5: The low content of sulfonic acid groups results in fewer dye binding sites. Although there is no ion aggregation, the dye uptake is limited, the leveling is slightly worse, and the color fastness is slightly reduced. The low proportion of sulfonic acid groups leads to better regularity of the polyester molecular chain. The hyperbranched grafted cool-feeling filler is dispersed without interference, the heat conduction channels are more complete, and Q-max and retention rate are slightly increased. The improved regularity of the molecular chain optimizes the fiber mechanical properties and slightly increases the breaking strength.

[0062] Example 6: The ordinary polyester polyol has a non-hyperbranched three-dimensional steric structure and is only linearly grafted. The overall steric hindrance effect is weaker than that of the pure hyperbranched system. The dispersion effect of sulfonic acid groups is slightly worse, and the color fastness is slightly reduced. The flexible chain segment reduces the fiber crystallinity while having a limited reinforcing effect, and the breaking strength is slightly reduced.

[0063] Example 7 features a high proportion of hyperbranched polyester polyol, with sufficient three-dimensional steric hindrance enabling efficient dispersion of sulfonic acid groups, uniform dye binding sites, and a slight increase in color fastness. The hyperbranched structure provides sufficient dispersion assistance to the cooling filler, and a small amount of ordinary polyester polyol improves matrix compatibility, resulting in more uniform filler dispersion, a slight increase in Q-max, and a slight increase in retention rate. The proportions comply with the claims, the grafted structure and molecular chain regularity are balanced, and the breaking strength is basically consistent with the benchmark, making it the best performing example among all compounding ratios.

[0064] In Example 8, the shear rate was much lower than that specified in claim 8. The polyester melt shear thinning effect was insufficient, the melt viscosity was too high, and the ion aggregation of sulfonic acid groups could not be weakened by shearing, resulting in a significant decrease in color fastness. In the high-viscosity melt, the cool-feeling filler was not sufficiently dispersed by shearing, resulting in local agglomeration, discontinuous heat conduction channels, a slight decrease in Q-max, and a slight decrease in retention rate. The low shear rate resulted in insufficient molecular chain orientation during spinning, poor fiber structure density, and a significant decrease in breaking strength.

[0065] Example 9 uses the lower limit of the leveling agent as described in claim 10. The dispersion effect of the dye in the dye bath is slightly poor, the dye is concentrated locally on the fiber surface, the leveling effect decreases, and the color fastness decreases slightly. The coolness-related properties and breaking strength are basically consistent with the benchmark.

[0066] Comparative Example 1 is a physical blending scheme of the prior art, without the covalent grafting effect of polyester polyol. The cooling filler is only physically dispersed, which has poor compatibility with the CDP matrix. It is easy to agglomerate and fall off during spinning and washing, and the heat conduction channels are severely damaged. Therefore, Q-max is greatly reduced and the retention rate after 50 washes drops sharply. Polyvinyl alcohol has no hyperbranched structure and cannot disperse sulfonic acid groups. Moreover, the hydroxyl groups of PVA compete with cationic dyes for sulfonic acid group binding sites, resulting in poor dye binding, serious surface floating color, and a significant decrease in color fastness. PVA and polyester matrix are heterogeneous materials with poor compatibility, which causes a large number of interface defects in the fiber molecular chain and significantly reduces the breaking strength. This fully highlights the inventiveness and beneficial effects of the grafting modification scheme of this invention.

[0067] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high-performance, easily dyeable, cooling fiber, characterized in that: The raw materials include the following parts by weight: 40-55 parts terephthalic acid, 18-25 parts ethylene glycol, 1-5 parts sodium isophthalate-5-sulfonate, 1-5 parts polyester polyol grafted cool-feeling filler, 0.01-0.05 parts catalyst, 0.01-0.10 parts anti-crosslinking agent, and 0.01-0.04 parts antioxidant.

2. The high-performance, easily dyeable, cooling fiber according to claim 1, characterized in that: The preparation steps of the polyester polyol grafted cooling filler are as follows: dispersing the cooling filler in propylene glycol, adding polyester polyol, adipic acid, and p-toluenesulfonic acid, heating and stirring to react, desolventizing under reduced pressure, and drying to obtain the polyester polyol grafted cooling filler.

3. The high-performance, easily dyeable, cooling fiber according to claim 1, characterized in that: The polyester polyols include ordinary polyester polyols and hyperbranched polyester polyols.

4. The high-performance, easily dyeable, cooling fiber according to claim 1, characterized in that: The mass ratio of sodium isophthalate-5-sulfonate and polyester polyol grafted cooling filler is (2-3):

4.

5. The high-performance, easily dyeable, cooling fiber according to claim 1, characterized in that: The mass ratio of the ethylene glycol and polyester polyol grafted cooling filler is (5-6):

1.

6. The high-performance, easily dyeable, cooling fiber according to claim 3, characterized in that: The mass ratio of the ordinary polyester polyol and the hyperbranched polyester polyol is 1:(2-3).

7. A method for preparing a high-performance, easily dyeable, cooling fiber according to any one of claims 1-6, characterized in that: The preparation process includes the following steps: weighing the raw materials according to their mass proportions, mixing them evenly, heating under nitrogen protection, maintaining the temperature during the reaction, raising the temperature, reducing the pressure and maintaining the temperature during the reaction, extruding and spinning, stretching and shaping, to obtain high-performance, easily dyeable, cool-feeling fibers.

8. The method for preparing high-performance, easily dyeable, cooling fiber according to claim 7, characterized in that: The extrusion spinning process has a zone temperature of 270±1℃, a zone temperature of 273±1℃, and a zone temperature of 275±1℃, with a shear rate of 940-960 s⁻¹.

9. The method for preparing high-performance, easily dyeable, cooling fiber according to claim 7, characterized in that: During the spinning process, the filaments are cooled by cold air at 25±3℃ with a wind speed of 0.8-1.0m / s.

10. A low-temperature dyeing process for high-performance, easily dyeable, cool-feeling fibers according to any one of claims 1-6, characterized in that: The dyeing process includes the following steps: fiber is immersed in a dye bath, heated to 55-65℃ at a rate of 1-3℃ / min, held for 25-35min, washed with water, and heated to 100-120℃ for 1-3min. The dye bath has a pH of 4.0-5.0 and contains 1-5% owf of cationic dye and 0.1-0.5g / L of leveling agent.

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