A full-dull cross-shaped profile fiber and a preparation method thereof

Abstract

The application discloses full-dull cross-shaped profiled fiber, the raw material of the cross-shaped profiled fiber includes PET polyester and a dulling agent, and the dulling agent is titanium dioxide with aluminum-silicon double-layer coating. The cross-shaped profiled fiber of the application adds titanium dioxide with aluminum-silicon double-layer coating, the aluminum-silicon double-layer coating shields the chemical active points of the titanium dioxide, and the thermal degradation of the polyester in the preparation process of the titanium dioxide master batch is reduced. The application further discloses a preparation method of the full-dull cross-shaped profiled fiber, and the preparation method comprises the following steps: preparing the PET polyester and the titanium dioxide master batch, melting the PET polyester and the titanium dioxide master batch to obtain a PET polyester melt, extruding the PET polyester melt from a spinning hole on a spinneret, and preparing the cross-shaped profiled fiber through an FDY spinning process. The preparation method of the application is good in controllability, and the prepared cross-shaped profiled fiber can accelerate moisture absorption and perspiration, keep the inside dry and clean.

Description

Technical Field

[0001] This invention relates to the field of spinning production technology, and in particular to a fully dull cross-shaped fiber and its preparation method. Background Technology

[0002] Ordinary round cross-section fibers have a weak surface luster, a waxy feel, and are prone to getting dirty, pilling, not absorbing water, and having poor coverage. By modifying the cross-section of fibers, the luster, bulkiness, moisture absorption, pilling resistance, stain resistance, stiffness, elasticity, and hand feel of textiles can be improved to varying degrees. Imitation silk, wool, linen, and animal fur can all be achieved by utilizing the physical properties of modified fibers in combination with other processing techniques.

[0003] Because polyester fibers have a smooth and transparent surface, they reflect light very strongly under visible light, a phenomenon commonly known as "aurora," which can be uncomfortable to the naked eye. To eliminate this uncomfortable reflection, a small amount of a substance with a different refractive index is added to the fiber, causing the light to diffuse in different directions, thus darkening the fiber's luster. This added substance is called a matting agent. Fully matte polyester fibers possess characteristics such as soft luster, good dyeability, high fabric drape, and strong shielding properties, making them widely applicable in high-end casual wear and wool-like fabrics.

[0004] However, as the titanium dioxide content increases, the viscosity of the polyester melt decreases, which has a significant impact on the flowability of the polyester. Generally, titanium dioxide is added as a masterbatch. During the process of making the masterbatch, titanium dioxide will cause thermal degradation of the polyester, making it impossible to produce polyester fibers with good performance.

[0005] Moisture-wicking fibers can regulate the microclimate inside clothing, instantly wicking away moisture and sweat to keep the skin dry and clean. Therefore, there is a strong demand for this fiber in sports, leisure, and underwear products, showcasing its economic, comfortable, and functional product features.

[0006] Generally, fabrics made from irregularly shaped fibers have better coverage and bulkiness than those made from ordinary synthetic fibers. They also tend to feel thicker, fluffier, fuller, lighter, and more breathable. The more complex the cross-section or the higher the degree of irregularity of the irregularly shaped fiber, the better the bulkiness and breathability of the fiber and fabric. How to further improve the degree of irregularity of fully matte irregularly shaped fibers has always been a challenge in fully matte products. Therefore, a new technical solution is urgently needed to address at least one of these technical problems. Summary of the Invention

[0007] In view of the above shortcomings, one object of the present invention is to provide a fully matte cross-shaped fiber, in which the aluminum-silicon double-layer coating shields the chemically active sites of titanium dioxide, reducing the thermal degradation of polyester during the preparation of titanium dioxide masterbatch. Another object of the present invention is to disclose a method for preparing fully matte cross-shaped fibers, which has good controllability and the prepared cross-shaped fibers can accelerate moisture absorption and perspiration, and keep the inside dry and clean.

[0008] To achieve the above-mentioned technical objectives and meet the above-mentioned technical requirements, the technical solution adopted by the present invention is as follows:

[0009] A fully matte cross-shaped fiber, characterized in that the raw material of the cross-shaped fiber includes PET polyester and a matting agent, wherein the matting agent is titanium dioxide with an aluminum-silicon double coating.

[0010] As a preferred technical solution, the content of the matting agent is 2.0-2.2 wt%.

[0011] This invention also provides a method for preparing fully dull cross-shaped fibers, comprising the following steps:

[0012] The PET polyester and titanium dioxide masterbatch are prepared, and the PET polyester and titanium dioxide masterbatch are melted to obtain PET polyester melt. The PET polyester melt is extruded from the spinneret orifice and then processed by FDY spinning process to obtain the cross-shaped fiber.

[0013] The spinneret is cross-shaped and includes a transverse flow channel and a vertical flow channel perpendicular to the transverse flow channel. The length ratio of the transverse flow channel to the vertical flow channel is 1:1. The intersection of the transverse flow channel and the vertical flow channel is the midpoint of the transverse flow channel. The width of the transverse flow channel and the vertical flow channel is the same. The length to width ratio of the vertical flow channel is (3.5-5.5):1.

[0014] As a preferred technical solution, the intrinsic viscosity of the PET polyester melt is 0.63-0.67 dL / g.

[0015] As a preferred technical solution, the specific steps for preparing the matting agent are as follows:

[0016] Weigh an appropriate amount of finely ground titanium dioxide, disperse it in deionized water to prepare a slurry with a mass concentration of 20-25 wt%, add sodium hexametaphosphate to prepare a slurry, adjust the pH to 10-11, stir the slurry evenly, heat to 80-85℃ and stir, gradually add 0.3 mol / L Na2SiO3·9H2O solution, where the mass of Na2SiO3 is 1.0-1.2% of titanium dioxide, then gradually add 1.6 wt% H2SO4 to maintain the pH stable at pH=9.5, after the addition is complete, age for 2-3 hours, then centrifuge, wash, dry and grind to obtain silicon-coated titanium dioxide;

[0017] Silicon-coated titanium dioxide was dispersed in deionized water to prepare a solution with a mass concentration of 20-25 wt%. Then, a 0.6 mol / L NaAlO2 solution was added dropwise, and 1.6 wt% H2SO4 was added simultaneously to maintain the pH at 9.0. The mass of NaAlO2 was 2.5-3.0% of the titanium dioxide. After the addition was complete, the solution was aged for 2-3 hours, and then centrifuged, washed, dried, and ground to obtain aluminum-silicon double-coated titanium dioxide.

[0018] Aluminum-silicon double-coated titanium dioxide was placed in a desiccator and SO2 gas was introduced at a temperature of 100-120℃, a gas flow rate of 3-5 m3 / h·kg, and a time of 2-3 h.

[0019] A mixed powder is obtained by mixing titanium dioxide with aluminum-silicon double coating, bright polyester and stabilizer in a weight percentage of (40-50):(60-50), and the amount of stabilizer added is 500-800 ppm of polyester mass.

[0020] The mixed powder is dried at a temperature of 150-170℃ for 12-15 hours, with the moisture content controlled to be less than 30ppm. The dried mixed powder is then fed into a twin-screw extruder for melt granulation at a temperature of 250-275℃ to obtain titanium dioxide masterbatch.

[0021] As a preferred technical solution, the intrinsic viscosity of the titanium dioxide masterbatch is 0.45-0.48 dL / g.

[0022] As a preferred technical solution, the intrinsic viscosity of the bright polyester is 0.64-0.67 dL / g.

[0023] As a preferred technical solution, the stabilizer is triphenyl phosphate.

[0024] As a preferred technical solution, the parameters of the FDY spinning process are: cooling temperature 20-25℃, first roller speed 2000-2200m / min, first roller temperature 75-85℃, second roller speed 2800-3000m / min, second roller temperature 130-140℃, and winding speed 2830-2920m / min.

[0025] As a preferred technical solution, the single filament fineness of the cross-shaped fiber is 0.8-1.2 dtex, the breaking strength is ≥3.30cN / dtex, the breaking elongation is 40±5.0%, the network density is 15±4 cells / m, the linear density deviation rate is ≤1.0%, the breaking strength CV value is ≤5.0%, the breaking elongation CV value is ≤10.0%, and the boiling water shrinkage rate is 7.5±0.5%.

[0026] Compared with traditional technical solutions, the beneficial effects of the present invention are:

[0027] 1) Titanium dioxide with aluminum-silicon double coating has a chemically inert oxide film layer that shields the chemically active sites of titanium dioxide, reducing the thermal degradation of polyester during the preparation of titanium dioxide masterbatch;

[0028] 2) The preparation method of the fully matte cross-shaped special fiber has good controllability, and the prepared cross-shaped special fiber can accelerate moisture absorption and perspiration, and keep the inside dry and clean;

[0029] 3) Based on the coating of titanium dioxide with silicon dioxide and aluminum oxide, SO2 gas is introduced to form the oxidation product SO4. 2- Because it occupies the active center of the catalyst, it also reduces the percentage of titanium atoms in the coated titanium dioxide surface, causing the catalytic activity of titanium dioxide to gradually become deactivated, further reducing the thermal degradation of polyester by titanium dioxide during masterbatch processing, and thus preparing profiled fibers with better shape retention.

[0030] 4) Adding a certain amount of stabilizer to the polymerization system reduces the coordination ability of titanium in titanium dioxide to carbonyl oxygen in polyester, which inhibits the activity of titanium dioxide catalyst and is beneficial to the processing and preparation of titanium dioxide masterbatch. Detailed Implementation

[0031] An embodiment of the present invention provides a fully matte cross-shaped fiber, wherein the raw materials of the cross-shaped fiber include PET polyester and a matting agent, and the matting agent is titanium dioxide with an aluminum-silicon double coating. The use of titanium dioxide with an aluminum-silicon double coating provides a chemically inert oxide film layer that shields the chemically active sites of titanium dioxide, thereby reducing the thermal degradation of polyester during the preparation of titanium dioxide masterbatch.

[0032] In some embodiments, the content of the matting agent is 2.0-2.2 wt% of the total raw material. If the content of the matting agent is less than 2.0 wt%, the matting effect will be poor. If the content of the matting agent is greater than 2.2 wt%, the surface friction of the cross-shaped fibers will be too large, resulting in phenomena such as fiber breakage and fiber drift.

[0033] This invention also provides a method for preparing fully dull cross-shaped fibers, comprising the following steps:

[0034] The PET polyester and titanium dioxide masterbatch are prepared, and the PET polyester and titanium dioxide masterbatch are melted to obtain PET polyester melt. The PET polyester melt is extruded from the spinneret orifice and then processed by FDY spinning process to obtain the cross-shaped fiber.

[0035] The spinneret is cross-shaped and includes a transverse flow channel and a vertical flow channel perpendicular to the transverse flow channel. The length ratio of the transverse flow channel to the vertical flow channel is 1:1. The intersection of the transverse and vertical flow channels is the midpoint of the transverse and vertical flow channels. The widths of the transverse and vertical flow channels are the same, and the length-to-width ratio of the vertical flow channel is (3.5-5.5):1. PET polyester melt is extruded from the spinneret to form highly irregular cross-shaped fibers. The resulting cross-shaped fibers accelerate moisture absorption and wicking, keeping the interior dry and clean. Because polymer melt undergoes an outlet expansion effect during extrusion, if the length-to-width ratio is close, the cross shape will be less pronounced, reducing the moisture absorption and wicking effect. The cross-shaped fibers form more gaps than round fibers, generating more capillary effect and accelerating moisture absorption and wicking.

[0036] In some embodiments, the intrinsic viscosity of the PET polyester melt is 0.63-0.67 dL / g, exhibiting good flowability.

[0037] In some embodiments, the specific steps for preparing the matting agent are as follows:

[0038] Weigh an appropriate amount of finely ground titanium dioxide, disperse it in deionized water to prepare a slurry with a mass concentration of 20-25 wt%, add sodium hexametaphosphate to prepare a slurry, adjust the pH to 10-11, stir the slurry evenly, heat to 80-85℃ and stir, gradually add 0.3 mol / L Na2SiO3·9H2O solution, where the mass of Na2SiO3 is 1.0-1.2% of the mass of titanium dioxide, then gradually add 1.6 wt% H2SO4 to maintain the pH stable at pH=9.5, after the addition is complete, age for 2-3 hours, then centrifuge, wash, dry and grind to obtain silicon-coated titanium dioxide;

[0039] Silicon-coated titanium dioxide was dispersed in deionized water to prepare a solution with a mass concentration of 20-25 wt%. Then, a 0.6 mol / L NaAlO2 solution was added dropwise, and 1.6 wt% H2SO4 was added simultaneously to maintain the pH at 9.0. The mass of NaAlO2 was 2.5-3.0% of the titanium dioxide. After the addition was complete, the solution was aged for 2-3 hours, and then centrifuged, washed, dried, and ground to obtain aluminum-silicon double-coated titanium dioxide.

[0040] Aluminum-silicon double-coated titanium dioxide is placed in a desiccator, and SO2 gas is introduced at a temperature of 100-120℃ and a gas flow rate of 3-5 m³ / h. 3 / h·kg, time 2-3h;

[0041] A mixed powder is obtained by mixing titanium dioxide with aluminum-silicon double coating, bright polyester and stabilizer. The weight percentage of titanium dioxide and bright polyester is (40-50):(60-50). The amount of stabilizer added is 500-800 ppm of the weight of bright polyester. The stabilizer is triphenyl phosphate.

[0042] The mixed powder is dried at a temperature of 150-170℃ for 12-15 hours, with the moisture content controlled to be less than 30ppm. The dried mixed powder is then fed into a twin-screw extruder for melt granulation at a temperature of 250-275℃ to obtain titanium dioxide masterbatch.

[0043] When using FDY spinning process to prepare profiled fibers, it is generally impossible to achieve the ideal design effect. In addition to the extrusion swelling effect that occurs when the polyester melt passes through the spinneret, another factor is that the viscosity of the polyester melt containing the matting agent is relatively low, resulting in a relatively "rounded" fiber cross-section without sharp edges, and poor shape retention of profiled fibers.

[0044] Titanium dioxide is a polymorphic inorganic compound, existing in the tetragonal rutile (R-type) and anatase (A-type) crystal systems, as well as the brookite type, whose properties fall between the two. Titanium dioxide is a wide-bandgap semiconductor; its valence band is formed by the hybridization of the 2p orbitals of oxygen and the 3d orbitals of iron. When the energy is greater than or equal to the bandgap (Eg), titanium dioxide exhibits certain catalytic activity. At high temperatures, electrons in the valence band of titanium dioxide are excited and transition to the empty conduction band, forming electron-hole pairs with strong redox properties. Electrons can be captured by O2 in the system to form free radicals O2·, while holes can oxidize H2O to form free radicals HO·. O2· and HO· have strong activity and can cause thermal degradation of polyester macromolecules, among other things. Although titanium dioxide has relatively low catalytic activity, its content can reach as high as 50% in the preparation of titanium dioxide masterbatch. This leads to severe thermal degradation of polyester. The intrinsic viscosity of titanium dioxide masterbatch is typically around 0.25-0.27 dL / g, far lower than that of polyester melt. Semi-dull polyester fibers usually contain around 0.2-0.25% titanium dioxide, while fully dull cross-shaped fibers contain 2.0-2.5%. The large amount of low-molecular-weight, bright polyester significantly impacts flowability. For fully dull products, where the titanium dioxide content is 7-8 times higher than in semi-dull products, titanium dioxide masterbatch is more likely to cause degradation during spinning. During spinning, the viscosity drop caused by titanium dioxide masterbatch in fully dull fibers can reach 0.020-0.030 dL / g, while the viscosity drop in semi-dull fibers is around 0.005-0.008 dL / g.

[0045] Because titanium dioxide possesses lattice defects and is a wide-bandgap semiconductor, it exhibits chemical reactivity. Therefore, a chemically inert oxide film can be coated onto the surface of titanium dioxide to shield its chemically active sites. The coating materials for titanium dioxide are silicon dioxide and aluminum oxide. However, surface coating with silicon dioxide and aluminum oxide cannot completely cover the titanium dioxide surface. In existing technologies, the percentage of titanium atoms on the surface of titanium dioxide coated with silicon dioxide and aluminum oxide is 13-18% (compared to 25-26% for uncoated titanium dioxide). This is because when the amount of NaAlO2 added reaches a certain value, some NaAlO2 crystallizes, making it impossible to further reduce the percentage of titanium atoms on the coated titanium dioxide surface.

[0046] This invention utilizes a double-layer coating of titanium dioxide with silicon dioxide and aluminum oxide to introduce SO2 gas, forming the oxidation product SO4. 2-Because it occupies the active center of the catalyst, it also reduces the percentage of titanium atoms on the surface of coated titanium dioxide, causing the catalyst to gradually become deactivated. This further reduces the thermal degradation of polyester by titanium dioxide during masterbatch processing, thereby preparing cross-shaped fibers with better shape retention. Adding a certain amount of stabilizer to the polymerization system reduces the coordination ability of titanium in titanium dioxide to carbonyl oxygen in polyester, inhibiting the catalyst activity and facilitating the preparation of titanium dioxide masterbatch.

[0047] In some embodiments, the intrinsic viscosity of the titanium dioxide masterbatch is 0.45-0.48 dL / g. When the intrinsic viscosity of the titanium dioxide masterbatch is lower than 0.45 dL / g or higher than 0.48 dL / g, the cross-shaped fiber forming effect is poor.

[0048] In some embodiments, the intrinsic viscosity of the glossy polyester is 0.64-0.67 dL / g. When the intrinsic viscosity of the glossy polyester is lower than 0.64 dL / g or higher than 0.67 dL / g, the cross-shaped fiber forming effect is poor.

[0049] In some embodiments, after the PET polyester melt is extruded from the spinneret holes, the FDY spinning process includes cooling, stretching, and winding. The parameters of the FDY spinning process are: cooling temperature 20-25℃, first roll speed 2000-2200m / min, first roll temperature 75-85℃, second roll speed 2800-3000m / min, second roll temperature 130-140℃, winding speed 2830-2920m / min, cooling is achieved by ring blowing, and stretching is performed between the first and second rolls.

[0050] In some embodiments, the cross-shaped fibers have a single filament fineness of 0.8-1.2 dtex, a breaking strength ≥3.30 cN / dtex, a breaking elongation of 40±5.0%, a network density of 15±4 cells / m, a linear density deviation rate ≤1.0%, a breaking strength CV value ≤5.0%, a breaking elongation CV value ≤10.0%, and a boiling water shrinkage rate of 7.5±0.5%. Example

[0051] A fully matte cross-shaped fiber, wherein the raw material of the cross-shaped fiber includes PET polyester and a matting agent, wherein the matting agent is titanium dioxide with an aluminum-silicon double coating, and the content of the matting agent is 2.0 wt%.

[0052] This invention also provides a method for preparing fully dull cross-shaped fibers, comprising the following steps:

[0053] The PET polyester and titanium dioxide masterbatch are prepared, and the PET polyester and titanium dioxide masterbatch are melted to obtain PET polyester melt. The PET polyester melt is extruded from the spinneret orifice and then processed by FDY spinning process to obtain the cross-shaped fiber.

[0054] The spinneret is cross-shaped and includes a transverse flow channel and a vertical flow channel perpendicular to the transverse flow channel. The length ratio of the transverse flow channel to the vertical flow channel is 1:1. The intersection of the transverse flow channel and the vertical flow channel is the midpoint of the transverse flow channel and the vertical flow channel. The width of the transverse flow channel and the vertical flow channel is the same. The length-to-width ratio of the vertical flow channel is 5.5:1. The intrinsic viscosity of the PET polyester melt is 0.63 dL / g.

[0055] The specific steps for preparing the matting agent are as follows:

[0056] Weigh an appropriate amount of finely ground titanium dioxide, disperse it in deionized water to prepare a slurry with a mass concentration of 20 wt%, add sodium hexametaphosphate to prepare a slurry, adjust the pH to 10, stir the slurry evenly, heat to 80℃ and stir, gradually add 0.3 mol / L Na2SiO3·9H2O solution, where the mass of Na2SiO3 is 1.0% of the mass of titanium dioxide, and then gradually add 1.6 wt% H2SO4 to maintain the pH stable at pH=9.5. After the addition is complete, age for 2 hours, then centrifuge, wash, dry and grind to obtain silicon-coated titanium dioxide;

[0057] Silicon-coated titanium dioxide was dispersed in deionized water to prepare a solution with a mass concentration of 20 wt%. Then, a 0.6 mol / L NaAlO2 solution was added dropwise, and 1.6 wt% H2SO4 was added simultaneously to maintain the pH at 9.0. The mass of NaAlO2 was 2.5% of the titanium dioxide. After the addition was complete, the solution was aged for 2-3 hours, and then centrifuged, washed, dried and ground to obtain aluminum-silicon double-coated titanium dioxide.

[0058] Aluminum-silicon double-coated titanium dioxide was placed in a desiccator, and SO2 gas was introduced at a temperature of 100℃ and a gas flow rate of 3m³. 3 / h·kg, time 2h;

[0059] A mixed powder was obtained by mixing titanium dioxide with aluminum-silicon double coating, bright polyester and stabilizer at a weight percentage of 40:60, and the amount of stabilizer added was 500 ppm of the weight of bright polyester.

[0060] The mixed powder is dried at 150°C for 12 hours, with the moisture content controlled to be less than 30 ppm. The dried mixed powder is then fed into a twin-screw extruder for melt granulation at a temperature of 250°C to obtain titanium dioxide masterbatch. The intrinsic viscosity of the titanium dioxide masterbatch is 0.45 dL / g, and the intrinsic viscosity of the bright polyester is 0.64 dL / g. The stabilizer is triphenyl phosphate.

[0061] The FDY spinning process consists of cooling, stretching, and winding. The parameters of the FDY spinning process are as follows: cooling temperature 20℃, first roller speed 2000m / min, first roller temperature 75℃, second roller speed 2800m / min, second roller temperature 130℃, winding speed 2830m / min, and stretching is performed between the first and second rollers.

[0062] The cross-shaped fiber has a single filament fineness of 0.8 dtex, a breaking strength of 4 cN / dtex, a breaking elongation of 35%, a network density of 11 filaments / m, a linear density deviation rate of 0.7%, a breaking strength CV value of 4.1%, a breaking elongation CV value of 8.5%, a boiling water shrinkage rate of 7%, and a wicking height greater than 155 mm. Example

[0063] A fully matte cross-shaped fiber, wherein the raw material of the cross-shaped fiber includes PET polyester and a matting agent, wherein the matting agent is titanium dioxide with an aluminum-silicon double coating, and the content of the matting agent is 2.1 wt%.

[0064] This invention also provides a method for preparing fully dull cross-shaped fibers, comprising the following steps:

[0065] The PET polyester and titanium dioxide masterbatch are prepared, and the PET polyester and titanium dioxide masterbatch are melted to obtain PET polyester melt. The PET polyester melt is extruded from the spinneret orifice and then processed by FDY spinning process to obtain the cross-shaped fiber.

[0066] The spinneret is cross-shaped and includes a transverse flow channel and a vertical flow channel perpendicular to the transverse flow channel. The length ratio of the transverse flow channel to the vertical flow channel is 1:1. The intersection of the transverse flow channel and the vertical flow channel is the midpoint of the transverse flow channel and the vertical flow channel. The width of the transverse flow channel and the vertical flow channel is the same. The length-to-width ratio of the vertical flow channel is 3.5:1. The intrinsic viscosity of the PET polyester melt is 0.65 dL / g.

[0067] The specific steps for preparing the matting agent are as follows:

[0068] Weigh an appropriate amount of finely ground titanium dioxide, disperse it in deionized water to prepare a slurry with a mass concentration of 23 wt%, add sodium hexametaphosphate to prepare a slurry, adjust the pH to 11, stir the slurry evenly, heat to 82℃ and stir, gradually add 0.3 mol / L Na2SiO3·9H2O solution, where the mass of Na2SiO3 is 1.1% of the mass of titanium dioxide, and then gradually add 1.6 wt% H2SO4 to maintain the pH stable at pH=9.5. After the addition is complete, age for 2.5 h, then centrifuge, wash, dry and grind to obtain silicon-coated titanium dioxide;

[0069] Silicon-coated titanium dioxide was dispersed in deionized water to prepare a solution with a mass concentration of 23 wt%. Then, a 0.6 mol / L NaAlO2 solution was added dropwise, and 1.6 wt% H2SO4 was added simultaneously to maintain the pH at 9.0. The mass of NaAlO2 was 2.7% of the titanium dioxide. After the addition was complete, the solution was aged for 2.5 h, and then centrifuged, washed, dried and ground to obtain aluminum-silicon double-coated titanium dioxide.

[0070] Aluminum-silicon double-coated titanium dioxide was placed in a desiccator, and SO2 gas was introduced at a temperature of 110℃ and a gas flow rate of 4 m³ / h. 3 / h·kg, time 2.5h;

[0071] A mixed powder is obtained by mixing titanium dioxide with aluminum-silicon double coating, bright polyester and stabilizer at a weight percentage of 45:55. The amount of stabilizer added is 500-800 ppm of polyester mass. The stabilizer is triphenyl phosphate.

[0072] The mixed powder was dried at 160°C for 13 hours, with the moisture content controlled to be less than 30 ppm. The dried mixed powder was then fed into a twin-screw extruder for melt granulation at a temperature of 260°C to obtain titanium dioxide masterbatch. The intrinsic viscosity of the titanium dioxide masterbatch was 0.46 dL / g, and the intrinsic viscosity of the bright polyester was 0.65 dL / g.

[0073] The FDY spinning process consists of cooling, stretching, and winding. The parameters of the FDY spinning process are: cooling temperature 23℃, first roller speed 2100m / min, first roller temperature 80℃, second roller speed 2900m / min, second roller temperature 135℃, winding speed 2900m / min, and stretching is performed between the first and second rollers.

[0074] The cross-shaped fiber has a single filament fineness of 1.1 dtex, a breaking strength of 4.27 cN / dtex, a breaking elongation of 42%, a network density of 16 cells / m, a linear density deviation rate of 0.9%, a breaking strength CV value of 4.2%, a breaking elongation CV value of 9.2%, a boiling water shrinkage rate of 7.8%, and a wicking height greater than 158 mm. Example

[0075] A fully matte cross-shaped fiber, wherein the raw material of the cross-shaped fiber includes PET polyester and a matting agent, wherein the matting agent is titanium dioxide with an aluminum-silicon double coating, and the content of the matting agent is 2.2 wt%.

[0076] This invention also provides a method for preparing fully dull cross-shaped fibers, comprising the following steps:

[0077] The PET polyester and titanium dioxide masterbatch are prepared, and the PET polyester and titanium dioxide masterbatch are melted to obtain PET polyester melt. The PET polyester melt is extruded from the spinneret orifice and then processed by FDY spinning process to obtain the cross-shaped fiber.

[0078] The spinneret is cross-shaped and includes a transverse flow channel and a vertical flow channel perpendicular to the transverse flow channel. The length ratio of the transverse flow channel to the vertical flow channel is 1:1. The intersection of the transverse flow channel and the vertical flow channel is the midpoint of the transverse flow channel and the vertical flow channel. The width of the transverse flow channel and the vertical flow channel is the same. The length-to-width ratio of the vertical flow channel is 4.5:1. The intrinsic viscosity of the PET polyester melt is 0.67 dL / g.

[0079] The specific steps for preparing the matting agent are as follows:

[0080] Weigh an appropriate amount of finely ground titanium dioxide, disperse it in deionized water to prepare a slurry with a mass concentration of 25 wt%, add sodium hexametaphosphate to prepare a slurry, adjust the pH to 11, stir the slurry evenly, heat to 85℃ and stir, gradually add 0.3 mol / L Na2SiO3·9H2O solution, where the mass of Na2SiO3 is 1.2% of titanium dioxide, then gradually add 1.6 wt% H2SO4 to maintain the pH stable at pH=9.5, after the addition is complete, age for 3 hours, then centrifuge, wash, dry and grind to obtain silicon-coated titanium dioxide;

[0081] Silicon-coated titanium dioxide was dispersed in deionized water to prepare a solution with a mass concentration of 25 wt%. Then, a 0.6 mol / L NaAlO2 solution was added dropwise, and 1.6 wt% H2SO4 was added simultaneously to maintain the pH at 9.0. The mass of NaAlO2 was 3.0% of the titanium dioxide. After the addition was complete, the solution was aged for 3 hours, and then centrifuged, washed, dried, and ground to obtain aluminum-silicon double-coated titanium dioxide.

[0082] Aluminum-silicon double-coated titanium dioxide was placed in a desiccator, and SO2 gas was introduced at a temperature of 120℃ and a gas flow rate of 5 m³ / h. 3 / h·kg, time 3h;

[0083] A mixed powder is obtained by mixing titanium dioxide with aluminum-silicon double coating, bright polyester and stabilizer at a weight percentage of 50:50. The amount of stabilizer added is 500-800 ppm of polyester mass. The stabilizer is triphenyl phosphate.

[0084] The mixed powder was dried at 170°C for 15 hours, with the moisture content controlled to be less than 30 ppm. The dried mixed powder was then fed into a twin-screw extruder for melt granulation at a temperature of 275°C to obtain titanium dioxide masterbatch. The intrinsic viscosity of the titanium dioxide masterbatch was 0.48 dL / g, and the intrinsic viscosity of the bright polyester was 0.67 dL / g.

[0085] The FDY spinning process consists of cooling, stretching, and winding. The parameters of the FDY spinning process are as follows: cooling temperature 25℃, first roller speed 2200m / min, first roller temperature 85℃, second roller speed 3000m / min, second roller temperature 140℃, winding speed 2920m / min, and stretching is performed between the first and second rollers.

[0086] The cross-shaped fiber has a single filament fineness of 1.2 dtex, a breaking strength of 4.46 cN / dtex, a breaking elongation of 45.0%, a network density of 19 filaments / m, a linear density deviation rate of 0.8%, a breaking strength CV value of 4.3%, a breaking elongation CV value of 9.4%, a boiling water shrinkage rate of 8%, and a wicking height greater than 153 mm.

[0087] The breaking strength of conventional fully dull fibers on the market is less than 3.00 cN / dtex, the linear density deviation rate is 2.0-3.0%, the breaking strength CV value is greater than 10.0%, the breaking elongation CV value is greater than 15.0%, and the wicking height is less than 150 mm.

[0088] Compared with conventional dull fibers on the market, the cross-shaped fibers prepared by Examples 1, 2 and 3 have better mechanical properties, better moisture absorption, better flowability of polyester melt during preparation, and less polyester degradation during the entire preparation process.

[0089] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values ​​less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are explicitly described in this specification in a similar manner.

[0090] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0091] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0092] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0093] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A method for preparing a fully matte cross-shaped fiber, characterized in that, The raw materials for the cross-shaped fibers include PET polyester and a matting agent, wherein the matting agent is titanium dioxide with an aluminum-silicon double-layer coating; the content of the matting agent is 2.0-2.2 wt%; the specific steps for preparing the matting agent are as follows: Weigh an appropriate amount of finely ground titanium dioxide, disperse it in deionized water to prepare a slurry with a mass concentration of 20-25 wt%, add sodium hexametaphosphate to prepare a slurry, adjust the pH to 10-11, stir the slurry evenly, heat to 80-85℃ and stir, gradually add 0.3 mol / L Na2SiO3·9H2O solution, where the mass of Na2SiO3 is 1.0-1.2% of titanium dioxide, then gradually add 1.6 wt% H2SO4 to maintain the pH stable at pH=9.5, after the addition is complete, age for 2-3 hours, then centrifuge, wash, dry and grind to obtain silicon-coated titanium dioxide; Silicon-coated titanium dioxide was dispersed in deionized water to prepare a solution with a mass concentration of 20-25 wt%. Then, a 0.6 mol / L NaAlO2 solution was added dropwise, and 1.6 wt% H2SO4 was added simultaneously to maintain the pH at 9.

0. The mass of NaAlO2 was 2.5-3.0% of the titanium dioxide. After the addition was complete, the solution was aged for 2-3 hours, and then centrifuged, washed, dried, and ground to obtain aluminum-silicon double-coated titanium dioxide. Aluminum-silicon double-coated titanium dioxide is placed in a desiccator, and SO2 gas is introduced at a temperature of 100-120℃ and a gas flow rate of 3-5 m³ / h. 3 / h·kg, time 2-3h; A mixed powder is obtained by mixing titanium dioxide with aluminum-silicon double coating, bright polyester and stabilizer in a weight percentage of (40-50):(60-50), and the amount of stabilizer added is 500-800 ppm of polyester mass. The mixed powder is dried at a temperature of 150-170℃ for 12-15 hours, with the moisture content controlled to be less than 30ppm. The dried mixed powder is then fed into a twin-screw extruder for melt granulation at a temperature of 250-275℃ to obtain titanium dioxide masterbatch. The preparation method of the fully dull cross-shaped fiber includes the following steps: The PET polyester and titanium dioxide masterbatch are prepared, and the PET polyester and titanium dioxide masterbatch are melted to obtain PET polyester melt. The PET polyester melt is extruded from the spinneret orifice and then processed by FDY spinning process to obtain the cross-shaped fiber. The spinneret orifice is cross-shaped and includes a transverse flow channel and a vertical flow channel perpendicularly disposed in the transverse flow channel. The length ratio of the transverse flow channel to the vertical flow channel is 1:

1. The intersection of the transverse flow channel and the vertical flow channel is the midpoint of the transverse flow channel and the vertical flow channel. The width of the transverse flow channel and the vertical flow channel is the same. The length to width ratio of the vertical flow channel is (3.5-5.5):

1.

2. The method for preparing fully dull cross-shaped fibers according to claim 1, characterized in that, The intrinsic viscosity of the PET polyester melt is 0.63-0.67 dL / g.

3. The method for preparing fully dull cross-shaped fibers according to claim 1, characterized in that, The intrinsic viscosity of the titanium dioxide masterbatch is 0.45-0.48 dL / g.

4. The method for preparing fully dull cross-shaped fibers according to claim 1, characterized in that, The intrinsic viscosity of bright polyester is 0.64-0.67 dL / g.

5. The method for preparing fully dull cross-shaped fibers according to claim 1, characterized in that, The stabilizer is triphenyl phosphate.

6. The method for preparing fully dull cross-shaped fibers according to claim 1, characterized in that, The parameters of the FDY spinning process are as follows: cooling temperature 20-25℃, first roll speed 2000-2200m / min, first roll temperature 75-85℃, second roll speed 2800-3000m / min, second roll temperature 130-140℃, and winding speed 2830-2920m / min.

7. The method for preparing the fully dull cross-shaped fiber according to claim 1, characterized in that, The cross-shaped fibers have a single filament fineness of 0.8-1.2 dtex, a breaking strength ≥3.30 cN / dtex, a breaking elongation of 40±5.0%, a network density of 15±4 cells / m, a linear density deviation rate ≤1.0%, a breaking strength CV value ≤5.0%, a breaking elongation CV value ≤10.0%, and a boiling water shrinkage rate of 7.5±0.5%.