Preparation method and application of normal-pressure cation dyeable modified PTT

Abstract

The invention relates to the technical field of modified polyester fibers, and discloses a preparation method and application of normal-pressure cation dyeable modified PTT. The preparation method comprises the following steps: S1, carrying out ring-opening copolymerization on ethylene oxide and glycidyl butyrate, and sequentially carrying out ester alcoholysis and hydroxyl sulfonation to obtain sulfopolyether containing at least two hydroxyl groups; and S2, carrying out copolymerization on terephthalic acid, propylene glycol and sulfo-polyether to obtain the normal-pressure cation dyeable modified PTT. According to the preparation method provided by the invention, the sulfonic acid group is introduced into the polyether molecular chain, so that the cationic dyeability of PTT can be improved to a greater extent.

Description

Technical Field

[0001] The present invention relates to the technical field of modified polyester fibers, and in particular to a preparation method and application of normal pressure cationic dyeable modified PTT. Background Art

[0002] PTT, short for poly(trimethylene terephthalate), is a new polyester material. Its unique "odd carbon effect" gives it a helical structure and excellent elasticity. PTT fibers combine the softness of nylon, the bulk of acrylic, and the stain resistance of polyester. PTT molecular chains lack hydrophilic groups and exhibit a certain degree of hydrophobicity. Disperse dyes are generally used for dyeing. However, compared to cationic dyes, disperse dyes have drawbacks such as poor environmental performance and dull color, which to some extent limits the application of PTT fibers.

[0003] Patent CN108624982B discloses a method for preparing a cationic-modified PTT copolyester fiber. The method comprises the following steps: reacting sodium dimethyl sulfonate (SIPM) with a diol to form an esterified product, then uniformly mixing the product with terephthalic acid and 1,3-propylene glycol, sequentially subjecting the product to an esterification reaction and a pre-polycondensation reaction, followed by the addition of polysiloxane and polyethylene glycol for a final polycondensation reaction to produce a cationic-modified PTT copolyester. This patent improves the cationic dyeability of PTT by introducing sodium dimethyl sulfonate and polyethylene glycol into the PTT molecular chain, but the effect is limited. Increasing the amount of sodium dimethyl sulfonate and polyethylene glycol can further improve the cationic dyeability of PTT, but it can adversely affect the fiber's mechanical properties. Summary of the Invention

[0004] To address the technical problem of limited effectiveness of existing methods for improving the cationic dyeability of PTT, the present invention provides a method for preparing and applying a normal-pressure cationic-dyeable modified PTT. Using this method, sulfonic acid groups are introduced into the polyether molecular chain, significantly improving the cationic dyeability of PTT.

[0005] The specific technical solutions of the present invention are: In a first aspect, the present invention provides a method for preparing a normal pressure cationic dyeable modified PTT, comprising: S1: After ring-opening copolymerization of ethylene oxide and glycidyl butyrate, ester hydrolysis and hydroxyl sulfonation are carried out in sequence to obtain a sulfopolyether containing at least two hydroxyl groups; S2: Copolymerizing terephthalic acid, propylene glycol and sulfopolyether to obtain normal pressure cationic dyeable modified PTT.

[0006] The present invention utilizes ring-opening copolymerization of ethylene oxide and glycidyl butyrate to form a copolyether with ester groups on its side chains. After ester alcoholysis, side chain hydroxyl groups can be introduced into the copolyether molecular chain. These side chain hydroxyl groups can produce the following two effects: 1) After sulfonation, some of the hydroxyl groups in the copolyether can impart sulfonic acid groups to the polyether molecular chain. Compared to conventional methods of introducing sulfonic acid groups into PTT molecular chains using modifiers containing two carboxyl groups and one sulfonic acid group (such as SIPM), the present invention connects sulfonic acid groups to the side chains of the polyether. This allows the flexible polyether segments to form amorphous regions with strong molecular chain mobility within the modified PTT, which facilitates the entry of cationic dyes. The sulfonic acid groups in these regions then bind to the cationic dyes and immobilize them within the modified PTT. This method allows for better coordination between the polyether segments and the sulfonic acid groups, significantly improving the cationic dyeability of the PTT.

[0007] 2) The side chain hydroxyl groups in the copolyether serve as branching points, which can limit the mobility of the molecular chains near the branching points to a certain extent, making it impossible for the molecular chains to be closely arranged. Therefore, the presence of an appropriate amount of side chains is conducive to the formation of more pores in the amorphous region of the modified PTT, thereby improving the cationic dyeability of the modified PTT.

[0008] Preferably, in step S1, the molar ratio of ethylene oxide to glycidyl butyrate is 1:0.1-0.2.

[0009] During the ring-opening copolymerization process to prepare a copolyether, if the proportion of glycidyl butyrate in the two monomers is too low, fewer sulfonic acid groups are subsequently introduced into the polyether side chains, hindering the synergistic effect between the polyether segments and the sulfonic acid groups, resulting in a decrease in the cationic dyeability of the modified PTT. If the proportion of glycidyl butyrate in the two monomers is too high, it restricts the molecular chain mobility of the polyether segments, also adversely affecting cationic dyeability. The present invention significantly improves the cationic dyeability of the modified PTT by controlling the molar ratio of ethylene oxide to glycidyl butyrate to 1:0.1-0.2.

[0010] Preferably, in step S1, the process of ring-opening copolymerization of ethylene oxide and glycidyl butyrate comprises: prepolymerizing ethylene oxide to a weight-average molecular weight of 500-800 Da, adding glycidyl butyrate, and ring-opening polymerization to a weight-average molecular weight of 5000-6000 Da.

[0011] By first prepolymerizing ethylene oxide and then adding glycidyl butyrate for copolymerization, it is helpful to ensure that there is a certain distance between adjacent side chain hydroxyl groups in the copolyether, so that the part connected to the PTT molecular chain has a flexible chain segment of a certain length, which is conducive to the formation of amorphous regions with strong molecular chain mobility in the modified PTT, thereby giving the modified PTT better cationic dyeability.

[0012] Preferably, in step S1, the hydroxyl sulfonation process comprises: subjecting the ester alcoholysis product to a sodium hydride sodium reaction, and then subjecting the product to a sulfonation reaction with 1,3-propane sultone; and the molar ratio of glycidyl butyrate, sodium hydride and 1,3-propane sultone is 1:0.7-0.9:0.7-0.9.

[0013] Preferably, in step S2, the amount of the sulfopolyether is 3.5-7% of the mass of the normal pressure cationic dyeable modified PTT.

[0014] Preferably, in step S2, before copolymerizing terephthalic acid, propylene glycol and sulfopolyether, an anti-see-through modifier is mixed in; the anti-see-through modifier includes TiO2, ZnO and CeO2, which are doped with Ag and have a silane coupling agent grafted on the surface.

[0015] The present invention combines TiO2, ZnO, and CeO2 to cover a wide light absorption band. Ag doping also creates a surface plasmon resonance effect, enhancing light absorption. Modifying PTT with the present invention's anti-see-through modifier imparts improved anti-see-through properties to fabrics.

[0016] Furthermore, the amount of the anti-see-through modifier added is 0.25-15% of the mass of the normal pressure cationic dyeable modified PTT.

[0017] Furthermore, the mass ratio of TiO2, ZnO and CeO2 is 1:0.5-1:0.5-1; the particle sizes of TiO2, ZnO and CeO2 are 100-500nm, 50-200nm and 100-300nm respectively.

[0018] Furthermore, the doping amount of Ag is 2-8% of the total mass of TiO2, ZnO and CeO2; and the amount of the silane coupling agent is 1-5% of the total mass of TiO2, ZnO and CeO2.

[0019] Furthermore, the silane coupling agent is one or more of KH-550, KH-560 and KH-570.

[0020] Furthermore, the preparation steps of the anti-see-through modifier include: immersing TiO2, ZnO and CeO2 into Ag +The solution is dried and then dispersed into a reaction solvent, and a hydrolyzed silane coupling agent is added. The reaction is carried out at 60-80° C. for 3-5 hours, and the product is separated to obtain an anti-see-through modifier.

[0021] Preferably, in step S2, the molar ratio of terephthalic acid to propylene glycol is 1:1.2-1.8.

[0022] Preferably, the specific process of step S2 includes: mixing terephthalic acid, propylene glycol and the first part of the catalyst, reacting at 235-245°C and 60-65kPa until the acid value reaches 10-18KOH / g, then reacting at 245-258°C and 20-25kPa for 60-70min, adding the second part of the catalyst, reacting at 240-258°C and 20-25kPa for 60-70min, adding the sulfopolyether, reacting at 250-255°C and 20-25kPa for 60-70min, reacting at 238-248°C and 1.1-1.15kPa for 60-80min, reacting at 248-260°C and 1.1-1.2kPa for 60-80min, and reacting at 260-275°C and 115-135Pa for 60-120min.

[0023] Furthermore, the first catalyst and the second catalyst are both tetrabutyl titanate, the total amount of the two catalysts is 0.04-0.1% of the mass of terephthalic acid, and the mass ratio of the first catalyst to the second catalyst is 1:7-9.

[0024] In a second aspect, the present invention provides an application of normal pressure cationically dyeable modified PTT in a composite fiber, wherein the composite fiber is a parallel composite fiber of PET and normal pressure cationically dyeable modified PTT; the normal pressure cationically dyeable modified PTT is prepared by the preparation method.

[0025] Preferably, the preparation step of the composite fiber comprises: pre-crystallizing and drying PET and normal pressure cationic dyeable modified PTT, and then spinning them in parallel to obtain the composite fiber.

[0026] Furthermore, the temperature of the pre-crystallization and drying is 120-140° C., and the time is 30-40 minutes.

[0027] Furthermore, the mass ratio of the PET to the normal pressure cationic dyeable modified PTT is 1:0.6-1.5.

[0028] Furthermore, during the parallel spinning process, the PET box temperature is 277-285°C, and the normal pressure cationic dyeable modified PTT box temperature is 265-275°C.

[0029] Compared with the prior art, the present invention has the following advantages: (1) In the present invention, sulfonic acid groups are introduced into the polyether molecular chain by ring-opening copolymerization of ethylene oxide and glycidyl butyrate, followed by ester hydrolysis and hydroxyl sulfonation, so that the sulfonic acid groups and the polyether segments form a better coordination, thereby improving the cationic dyeability of PTT to a greater extent.

[0030] (2) In the process of preparing sulfopolyether, the present invention adopts a method of first prepolymerizing ethylene oxide and then adding glycidyl butyrate for copolymerization, and controlling the ratio between ethylene oxide and glycidyl butyrate within a specific range, which can further improve the cationic dyeability of the modified PTT.

[0031] (3) The present invention introduces Ag-doped TiO2, ZnO and CeO2 in the process of preparing the modified PTT, which can utilize the coordination between TiO2, ZnO and CeO2 to cover a wider light absorption band, and utilize the surface plasmon resonance effect formed by Ag doping to improve the light absorption capacity, thereby giving the fabric better anti-see-through performance. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the embodiments.

[0033] Overall embodiment First, the present invention relates to a method for preparing a normal pressure cationic dyeable modified PTT, comprising: S1: After ring-opening copolymerization of ethylene oxide and glycidyl butyrate, ester hydrolysis and hydroxyl sulfonation are carried out in sequence to obtain a sulfopolyether containing at least two hydroxyl groups; S2: Copolymerizing terephthalic acid, propylene glycol and sulfopolyether to obtain normal pressure cationic dyeable modified PTT.

[0034] In some specific embodiments, in step S1, the molar ratio of ethylene oxide to glycidyl butyrate is 1:0.1-0.2.

[0035] In some specific embodiments, in step S1, the process of ring-opening copolymerization of ethylene oxide and glycidyl butyrate includes: pre-polymerizing ethylene oxide to a weight-average molecular weight of 500-800 Da, adding glycidyl butyrate, and ring-opening polymerization to a weight-average molecular weight of 5000-6000 Da.

[0036] In some specific embodiments, in step S1, the hydroxyl sulfonation process includes: reacting the ester alcoholysis product with sodium hydride for sodiumization, and then reacting it with 1,3-propane sultone for sulfonation; the molar ratio of glycidyl butyrate, sodium hydride and 1,3-propane sultone is 1:0.7-0.9:0.7-0.9.

[0037] In some specific implementations, the specific process of step S1 includes: S1.1: Ethylene oxide, a ring-opening polymerization catalyst, and reaction solvent I are mixed and prepolymerized to a weight-average molecular weight of 500-800 Da. Glycidyl butyrate is then added and ring-opening polymerization is carried out to a weight-average molecular weight of 5000-6000 Da. The product is separated to obtain a ring-opening copolymer product. S1.2: Mixing the ring-opening copolymerization product with an alcoholysis catalyst and reaction solvent II to carry out an ester alcoholysis reaction, and separating the product to obtain an ester alcoholysis product; S1.3: The ester alcoholysis product is mixed with sodium hydride and reaction solvent III to carry out a sodiumization reaction, and then a mixture of 1,3-propane sultone and reaction solvent III is added to carry out a sulfonation reaction. The product is separated to obtain a sulfopolyether containing at least two hydroxyl groups.

[0038] In the above specific implementation manner, optionally or preferably: In step S1.1, the ring-opening polymerization catalyst is a composite catalyst of triisobutylaluminum, phosphoric acid, and 1,8-diazobisspiro[5.4.0]undec-7-ene (DBU), and the amount used is 8-15% of the mass of ethylene oxide; the temperature of the prepolymerization and the ring-opening polymerization is 20-30°C; In step S1.2, the alcoholysis catalyst is 1,5,7-triazabicyclo[4.4.0]decene-5-ene (TBD), and the amount used is 3-6% of the mass of the ring-opening copolymerization product; the temperature of the ester alcoholysis reaction is 20-30° C., and the time is 7-10 hours; In step S1.3, the temperature of the sodiumization reaction is 20-30° C., and the time is 5-7 h; the time of the sulfonation reaction is 50-60° C., and the time is 8-12 h.

[0039] In some specific embodiments, in step S2, the amount of the sulfopolyether is 3.5-7% of the mass of the normal pressure cationic dyeable modified PTT.

[0040] In some specific embodiments, in step S2, before copolymerizing terephthalic acid, propylene glycol and sulfopolyether, an anti-see-through modifier is mixed in; the anti-see-through modifier includes TiO2, ZnO and CeO2, which are doped with Ag and have a silane coupling agent grafted on the surface.

[0041] In the above specific implementation manner, optionally or preferably: The amount of the anti-see-through modifier added is 0.25-15% of the mass of the normal pressure cationic dyeable modified PTT; The mass ratio of TiO2, ZnO and CeO2 is 1:0.5-1:0.5-1; The particle sizes of TiO2, ZnO and CeO2 are 100-500nm, 50-200nm and 100-300nm respectively; The doping amount of Ag is 2-8% of the total mass of TiO2, ZnO and CeO2; The silane coupling agent is one or more of KH-550, KH-560 and KH-570, and the amount used is 1-5% of the total mass of TiO2, ZnO and CeO2; The preparation steps of the anti-perspective modifier include: immersing TiO2, ZnO and CeO2 into Ag + The solution is dried and then dispersed into a reaction solvent, and a hydrolyzed silane coupling agent is added. The reaction is carried out at 60-80° C. for 3-5 hours, and the product is separated to obtain an anti-see-through modifier.

[0042] In some specific embodiments, in step S2, the molar ratio of terephthalic acid to propylene glycol is 1:1.2-1.8.

[0043] In some specific embodiments, the specific process of step S2 includes: mixing terephthalic acid, propylene glycol and the first part of the catalyst, reacting at 235-245°C and 60-65kPa until the acid value reaches 10-18KOH / g, then reacting at 245-258°C and 20-25kPa for 60-70min, adding the second part of the catalyst, reacting at 240-258°C and 20-25kPa for 60-70min, adding the sulfopolyether, reacting at 250-255°C and 20-25kPa for 60-70min, reacting at 238-248°C and 1.1-1.15kPa for 60-80min, reacting at 248-260°C and 1.1-1.2kPa for 60-80min, and reacting at 260-275°C and 115-135Pa for 60-120min.

[0044] In the above specific implementation manner, optionally or preferably: The first catalyst and the second catalyst are both tetrabutyl titanate, the total amount of the two catalysts is 0.04-0.1% of the mass of terephthalic acid, and the mass ratio of the first catalyst to the second catalyst is 1:7-9.

[0045] Second, the present invention relates to the application of normal pressure cationically dyeable modified PTT in composite fibers, wherein the composite fibers are parallel composite fibers of PET and normal pressure cationically dyeable modified PTT; the normal pressure cationically dyeable modified PTT is prepared by the preparation method.

[0046] In some specific embodiments, the preparation step of the composite fiber includes: pre-crystallizing and drying PET and normal pressure cationic dyeable modified PTT, and then spinning them in parallel to obtain the composite fiber.

[0047] In the above specific implementation manner, optionally or preferably: The pre-crystallization and drying process is carried out at a temperature of 120-140° C. and for a time of 30-40 minutes; The mass ratio of the PET to the normal pressure cationic dyeable modified PTT is 1:0.6-1.5; During the parallel spinning process, the box temperature of PET is 277-285°C, and the box temperature of normal pressure cationic dyeable modified PTT is 265-275°C. Specific embodiments The present invention is described below by way of specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit and scope of the inventive concept, any changes and advantages that can be imagined by those skilled in the art are included in the present invention, and the scope of protection of the present invention is defined by the appended claims and any equivalents thereof.

[0049] Example 1 The modified PTT was prepared by the following steps and further made into composite fibers and fabrics: S1: Preparation of sulfopolyether Prepare triisobutylaluminum, phosphoric acid, and dibutyl butyl (DBU) in a molar ratio of 1:0.35:0.25. Dissolve triisobutylaluminum in toluene to prepare a 1 mol / L solution I. Dissolve phosphoric acid in diethyl ether to prepare a 1 mol / L solution II. After displacing the air in the reactor with dry nitrogen, add solution I to the reactor. Then, add solution II dropwise at 0°C with stirring. Continue stirring for 15 minutes after addition. Then, add DBU and stir at 45°C for 3 hours to obtain a ring-opening polymerization catalyst solution.

[0050] After replacing the air in the polymerization reactor with dry nitrogen, ethylene oxide and toluene were added to the polymerization reactor, and then the ring-opening polymerization catalyst solution was added and stirred at 25°C until the reaction temperature reached M. w When the concentration reaches 510Da, glycidyl butyrate was added and the reaction was continued at 25°C with stirring until the reaction temperature reached M w After reaching 5037 Da, n-hexane was added to precipitate the product, which was then filtered to obtain a ring-opening copolymerization product. The molar ratio of ethylene oxide to glycidyl butyrate was 1:0.1; the amount of ring-opening polymerization catalyst used was 9% of the mass of ethylene oxide; and the mass-to-volume ratio of ethylene oxide to toluene was 1 g:10 mL.

[0051] Add the ring-opening copolymerization product, TBD, and methanol to an ester alcoholysis reactor and stir at 25°C for 10 hours. Add tetrahydrofuran to precipitate the product, then filter to obtain the ester alcoholysis product. The TBD content is 4% of the mass of the ring-opening copolymerization product, and the mass-to-volume ratio of the ring-opening copolymerization product to methanol is 1 g:10 mL.

[0052] The ester alcoholysis product and toluene were added to a sulfonation reactor. After complete dissolution, sodium hydride was slowly added with stirring. The reaction was stirred at 25°C for 6 hours. The temperature was then raised to 55°C, and 1,3-propane sultone was slowly added with stirring. The reaction was stirred for 10 hours. The toluene was removed by vacuum rotary evaporation, and the product was dissolved in a 1:1 mixture of water and isopropanol. The product was washed twice with petroleum ether, vacuum rotary evaporation, and recrystallization was performed twice with anhydrous ethanol to obtain a sulfopolyether. The molar ratio of glycidyl butyrate, sodium hydride, and 1,3-propane sultone was 1:0.7:0.7, and the mass-to-volume ratio of the ester alcoholysis product to toluene was 1 g:10 mL.

[0053] S2: Preparation of anti-see-through modifier TiO2, ZnO, and CeO2 with particle sizes of 100-500nm, 50-200nm, and 100-300nm, respectively, were immersed in an AgNO3 solution and dried to produce Ag-doped nanoparticles. The mass ratio of TiO2, ZnO, and CeO2 was 1:0.5:0.5, and the Ag doping level was 5% of the total mass of the TiO2, ZnO, and CeO2.

[0054] Ag-doped nanoparticles were dispersed in propylene glycol, and the hydrolyzed silane coupling agent KH-550 was added. The mixture was stirred and reacted at 70°C for 4 hours. After filtration, the mixture was washed with propylene glycol and dried to obtain an anti-see-through modifier. The amount of silane coupling agent KH-550 was 3% of the total mass of TiO2, ZnO, and CeO2.

[0055] S3: Preparation of modified PTT Terephthalic acid, propylene glycol, an anti-see-through modifier, tetrabutyl titanate, a stabilizer, trimethyl phosphate, and an anti-ether agent, sodium acetate, were added to a beating tank for beating. The mixture was then introduced into an esterification reactor I, where it reacted at 240°C and 60kPa until the acid value reached 13KOH / g. The mixture was then introduced into an esterification reactor II. In esterification reactor II, the mixture first entered chamber I and reacted at 250°C and 20kPa for 60 minutes. The mixture then entered chamber II and mixed with tetrabutyl titanate, reacted at 250°C and 20kPa for 60 minutes, and then entered chamber III and mixed with a sulfopolyether, reacted at 250°C and 20kPa for 60 minutes. The mixture was then introduced into a polycondensation reactor. In the polycondensation reactor, the material is first reacted in chamber 1 at 245°C and 1.1 kPa for 70 minutes, then in chamber 2 at 255°C and 1.15 kPa for 70 minutes, and finally in chamber 3 at 270°C and 125 Pa for 90 minutes. The material is discharged to obtain modified PTT. The molar ratio of terephthalic acid to propylene glycol is 1:1.2; the amount of the anti-see-through modifier is 12% by weight of the modified PTT; the amount of trimethyl phosphate is 0.002% by weight of the modified PTT; the amount of sodium acetate is 0.02% by weight of the modified PTT; the total amount of tetrabutyl titanate is 0.5% by weight of the terephthalic acid (the mass ratio of tetrabutyl titanate added in the pulping stage to the esterification stage is 1:9); and the amount of sulfopolyether is 7% by weight of the modified PTT.

[0056] S4: Preparation of parallel composite fibers Modified PTT and normal pressure cationic dyeable PET (Hengyi, CDP) with a mass ratio of 1:1 were kept at 130°C for 30 minutes and then spun in parallel, wherein the box temperature of modified PTT was 270°C and the box temperature of normal pressure cationic dyeable PET was 280°C. Subsequently, they were subjected to ring cooling heating, side blowing, and oiling, and then wound at a speed of 4500m / min to obtain PTT / PET parallel composite fibers (75D / 72F FDY).

[0057] S5: Fabric Preparation The PTT / PET parallel composite fibers were woven to obtain a fabric. During the weaving process, a compact spinning process (twist of 900 twists / m) was used to increase the yarn density, and a high-density plain weave structure was selected, with warp density × weft density = 200 × 120 strands / inch.

[0058] Example 2 The modified PTT was prepared by the following steps and further made into composite fibers and fabrics: S1: Preparation of sulfopolyether Prepare triisobutylaluminum, phosphoric acid, and dibutyl butyl (DBU) in a molar ratio of 1:0.35:0.25. Dissolve triisobutylaluminum in toluene to prepare a 1 mol / L solution I. Dissolve phosphoric acid in diethyl ether to prepare a 1 mol / L solution II. After displacing the air in the reactor with dry nitrogen, add solution I to the reactor. Then, add solution II dropwise at 0°C with stirring. Continue stirring for 15 minutes after addition. Then, add DBU and stir at 45°C for 3 hours to obtain a ring-opening polymerization catalyst solution.

[0059] After replacing the air in the polymerization reactor with dry nitrogen, ethylene oxide and toluene were added to the polymerization reactor, and then the ring-opening polymerization catalyst solution was added and stirred at 25°C until the reaction temperature reached M. w When the concentration reaches 774Da, glycidyl butyrate was added and the reaction was continued at 25℃ with stirring until the reaction temperature reached M w After reaching 5969 Da, n-hexane was added to precipitate the product, which was then filtered to obtain a ring-opening copolymerization product. The molar ratio of ethylene oxide to glycidyl butyrate was 1:0.2; the amount of ring-opening polymerization catalyst used was 9% of the mass of ethylene oxide; and the mass-to-volume ratio of ethylene oxide to toluene was 1 g:10 mL.

[0060] Add the ring-opening copolymerization product, TBD, and methanol to an ester alcoholysis reactor and stir at 25°C for 10 hours. Add tetrahydrofuran to precipitate the product, then filter to obtain the ester alcoholysis product. The TBD content is 4% of the mass of the ring-opening copolymerization product, and the mass-to-volume ratio of the ring-opening copolymerization product to methanol is 1 g:10 mL.

[0061] The ester alcoholysis product and toluene were added to a sulfonation reactor. After complete dissolution, sodium hydride was slowly added with stirring. The reaction was stirred at 25°C for 6 hours. The temperature was then raised to 55°C, and 1,3-propane sultone was slowly added with stirring. The reaction was stirred for 10 hours. The toluene was removed by vacuum rotary evaporation, and the product was dissolved in a 1:1 mixture of water and isopropanol. The product was washed twice with petroleum ether, vacuum rotary evaporation, and recrystallization was performed twice with anhydrous ethanol to obtain a sulfopolyether. The molar ratio of glycidyl butyrate, sodium hydride, and 1,3-propane sultone was 1:0.9:0.9, and the mass-to-volume ratio of the ester alcoholysis product to toluene was 1 g:10 mL.

[0062] S2: Preparation of anti-see-through modifier TiO2, ZnO, and CeO2 with particle sizes of 100-500nm, 50-200nm, and 100-300nm, respectively, were immersed in an AgNO3 solution and dried to produce Ag-doped nanoparticles. The mass ratio of TiO2, ZnO, and CeO2 was 1:0.5:0.5, and the Ag doping level was 5% of the total mass of the TiO2, ZnO, and CeO2.

[0063] Ag-doped nanoparticles were dispersed in propylene glycol, and the hydrolyzed silane coupling agent KH-550 was added. The mixture was stirred and reacted at 70°C for 4 hours. After filtration, the mixture was washed with propylene glycol and dried to obtain an anti-see-through modifier. The amount of silane coupling agent KH-550 was 3% of the total mass of TiO2, ZnO, and CeO2.

[0064] S3: Preparation of modified PTT Terephthalic acid, propylene glycol, an anti-see-through modifier, tetrabutyl titanate, a stabilizer, trimethyl phosphate, and an anti-ether agent, sodium acetate, were added to a beating tank for beating. The mixture was then introduced into an esterification reactor I, where it reacted at 240°C and 60kPa until the acid value reached 13KOH / g. The mixture was then introduced into an esterification reactor II. In esterification reactor II, the mixture first entered chamber I and reacted at 250°C and 20kPa for 60 minutes. The mixture then entered chamber II and mixed with tetrabutyl titanate, reacted at 250°C and 20kPa for 60 minutes, and then entered chamber III and mixed with a sulfopolyether, reacted at 250°C and 20kPa for 60 minutes. The mixture was then introduced into a polycondensation reactor. In the polycondensation reactor, the material is first reacted in chamber 1 at 245°C and 1.1 kPa for 70 minutes, then in chamber 2 at 255°C and 1.15 kPa for 70 minutes, and finally in chamber 3 at 270°C and 125 Pa for 90 minutes. The material is discharged to obtain modified PTT. The molar ratio of terephthalic acid to propylene glycol is 1:1.2; the amount of the anti-see-through modifier is 12% by weight of the modified PTT; the amount of trimethyl phosphate is 0.002% by weight of the modified PTT; the amount of sodium acetate is 0.02% by weight of the modified PTT; the total amount of tetrabutyl titanate is 0.5% by weight of the terephthalic acid (the mass ratio of tetrabutyl titanate added in the beating stage to the esterification stage is 1:9); and the amount of sulfopolyether is 3.5% by weight of the modified PTT.

[0065] S4: Preparation of parallel composite fibers Modified PTT and normal pressure cationic dyeable PET (Hengyi, CDP) with a mass ratio of 1:1 were kept at 130°C for 30 minutes and then spun in parallel, wherein the box temperature of modified PTT was 270°C and the box temperature of normal pressure cationic dyeable PET was 280°C. Subsequently, they were subjected to ring cooling heating, side blowing, and oiling, and then wound at a speed of 4500m / min to obtain PTT / PET parallel composite fibers (75D / 72F FDY).

[0066] S5: Fabric Preparation The PTT / PET parallel composite fibers were woven to obtain a fabric. During the weaving process, a compact spinning process (twist of 900 twists / m) was used to increase the yarn density, and a high-density plain weave structure was selected, with warp density × weft density = 200 × 120 strands / inch.

[0067] Example 3 The only difference between this embodiment and embodiment 2 is that in step S1, ethylene oxide prepolymerization is not performed during the preparation of the ring-opening copolymerization product, and ethylene oxide and glycidyl butyrate are directly copolymerized; the remaining steps are the same as those in embodiment 2. Specifically, the steps for preparing the modified PTT, composite fiber, and fabric in this embodiment are as follows: S1: Preparation of sulfopolyether Prepare triisobutylaluminum, phosphoric acid, and dibutyl butyl (DBU) in a molar ratio of 1:0.35:0.25. Dissolve triisobutylaluminum in toluene to prepare a 1 mol / L solution I. Dissolve phosphoric acid in diethyl ether to prepare a 1 mol / L solution II. After displacing the air in the reactor with dry nitrogen, add solution I to the reactor. Then, add solution II dropwise at 0°C with stirring. Continue stirring for 15 minutes after addition. Then, add DBU and stir at 45°C for 3 hours to obtain a ring-opening polymerization catalyst solution.

[0068] After replacing the air in the polymerization reactor with dry nitrogen, ethylene oxide, glycidyl butyrate and toluene were added to the polymerization reactor, and then the ring-opening polymerization catalyst solution was added. The reaction was stirred at 25°C until M w After reaching 5602 Da, n-hexane was added to precipitate the product, which was then filtered to obtain a ring-opening copolymerization product. The molar ratio of ethylene oxide to glycidyl butyrate was 1:0.2; the amount of ring-opening polymerization catalyst used was 9% of the mass of ethylene oxide; and the mass-to-volume ratio of ethylene oxide to toluene was 1 g:10 mL.

[0069] Add the ring-opening copolymerization product, TBD, and methanol to an ester alcoholysis reactor and stir at 25°C for 10 hours. Add tetrahydrofuran to precipitate the product, then filter to obtain the ester alcoholysis product. The TBD content is 4% of the mass of the ring-opening copolymerization product, and the mass-to-volume ratio of the ring-opening copolymerization product to methanol is 1 g:10 mL.

[0070] The ester alcoholysis product and toluene were added to a sulfonation reactor. After complete dissolution, sodium hydride was slowly added with stirring. The reaction was stirred at 25°C for 6 hours. The temperature was then raised to 55°C, and 1,3-propane sultone was slowly added with stirring. The reaction was stirred for 10 hours. The toluene was removed by vacuum rotary evaporation, and the product was dissolved in a 1:1 mixture of water and isopropanol. The product was washed twice with petroleum ether, vacuum rotary evaporation, and recrystallization was performed twice with anhydrous ethanol to obtain a sulfopolyether. The molar ratio of glycidyl butyrate, sodium hydride, and 1,3-propane sultone was 1:0.9:0.9, and the mass-to-volume ratio of the ester alcoholysis product to toluene was 1 g:10 mL.

[0071] S2: Preparation of anti-see-through modifier TiO2, ZnO, and CeO2 with particle sizes of 100-500nm, 50-200nm, and 100-300nm, respectively, were immersed in an AgNO3 solution and dried to produce Ag-doped nanoparticles. The mass ratio of TiO2, ZnO, and CeO2 was 1:0.5:0.5, and the Ag doping level was 5% of the total mass of the TiO2, ZnO, and CeO2.

[0072] Ag-doped nanoparticles were dispersed in propylene glycol, and the hydrolyzed silane coupling agent KH-550 was added. The mixture was stirred and reacted at 70°C for 4 hours. After filtration, the mixture was washed with propylene glycol and dried to obtain an anti-see-through modifier. The amount of silane coupling agent KH-550 was 3% of the total mass of TiO2, ZnO, and CeO2.

[0073] S3: Preparation of modified PTT Terephthalic acid, propylene glycol, an anti-see-through modifier, tetrabutyl titanate, a stabilizer, trimethyl phosphate, and an anti-ether agent, sodium acetate, were added to a beating tank for beating. The mixture was then introduced into an esterification reactor I, where it reacted at 240°C and 60kPa until the acid value reached 13KOH / g. The mixture was then introduced into an esterification reactor II. In esterification reactor II, the mixture first entered chamber I and reacted at 250°C and 20kPa for 60 minutes. The mixture then entered chamber II and mixed with tetrabutyl titanate, reacted at 250°C and 20kPa for 60 minutes, and then entered chamber III and mixed with a sulfopolyether, reacted at 250°C and 20kPa for 60 minutes. The mixture was then introduced into a polycondensation reactor. In the polycondensation reactor, the material is first reacted in chamber 1 at 245°C and 1.1 kPa for 70 minutes, then in chamber 2 at 255°C and 1.15 kPa for 70 minutes, and finally in chamber 3 at 270°C and 125 Pa for 90 minutes. The material is discharged to obtain modified PTT. The molar ratio of terephthalic acid to propylene glycol is 1:1.2; the amount of the anti-see-through modifier is 12% by weight of the modified PTT; the total amount of trimethyl phosphate is 0.002% by weight of the modified PTT; the amount of sodium acetate is 0.02% by weight of the modified PTT; the amount of tetrabutyl titanate is 0.5% by weight of the terephthalic acid (the mass ratio of tetrabutyl titanate added in the beating stage to the esterification stage is 1:9); and the amount of sulfopolyether is 3.5% by weight of the modified PTT.

[0074] S4: Preparation of parallel composite fibers Modified PTT and normal pressure cationic dyeable PET (Hengyi, CDP) with a mass ratio of 1:1 were kept at 130°C for 30 minutes and then spun in parallel, wherein the box temperature of modified PTT was 270°C and the box temperature of normal pressure cationic dyeable PET was 280°C. Subsequently, they were subjected to ring cooling heating, side blowing, and oiling, and then wound at a speed of 4500m / min to obtain PTT / PET parallel composite fibers (75D / 72F FDY).

[0075] S5: Fabric Preparation The PTT / PET parallel composite fibers were woven to obtain a fabric. During the weaving process, a compact spinning process (twist of 900 twists / m) was used to increase the yarn density, and a high-density plain weave structure was selected, with warp density × weft density = 200 × 120 strands / inch.

[0076] Example 4 The only difference between this embodiment and embodiment 2 is that in step S1, the proportion of glycidyl butyrate in the two monomers is increased during the preparation of the ring-opening copolymerization product; the remaining steps are the same as those in embodiment 2. Specifically, the steps for preparing the modified PTT, composite fiber and fabric in this embodiment are as follows: S1: Preparation of sulfopolyether Prepare triisobutylaluminum, phosphoric acid, and dibutyl butyl (DBU) in a molar ratio of 1:0.35:0.25. Dissolve triisobutylaluminum in toluene to prepare a 1 mol / L solution I. Dissolve phosphoric acid in diethyl ether to prepare a 1 mol / L solution II. After displacing the air in the reactor with dry nitrogen, add solution I to the reactor. Then, add solution II dropwise at 0°C with stirring. Continue stirring for 15 minutes after addition. Then, add DBU and stir at 45°C for 3 hours to obtain a ring-opening polymerization catalyst solution.

[0077] After replacing the air in the polymerization reactor with dry nitrogen, ethylene oxide and toluene were added to the polymerization reactor, and then the ring-opening polymerization catalyst solution was added and stirred at 25°C until the reaction temperature reached M. w When the concentration reaches 785Da, glycidyl butyrate was added and the reaction was continued at 25℃ with stirring until the reaction temperature reached M w After reaching 5985Da, n-hexane was added to precipitate the product, which was then filtered to obtain a ring-opening copolymerization product. The molar ratio of ethylene oxide to glycidyl butyrate was 1:0.4; the amount of ring-opening polymerization catalyst used was 9% of the mass of ethylene oxide; and the mass-to-volume ratio of ethylene oxide to toluene was 1g:10mL.

[0078] Add the ring-opening copolymerization product, TBD, and methanol to an ester alcoholysis reactor and stir at 25°C for 10 hours. Add tetrahydrofuran to precipitate the product, then filter to obtain the ester alcoholysis product. The TBD content is 4% of the mass of the ring-opening copolymerization product, and the mass-to-volume ratio of the ring-opening copolymerization product to methanol is 1 g:10 mL.

[0079] The ester alcoholysis product and toluene were added to a sulfonation reactor. After complete dissolution, sodium hydride was slowly added with stirring. The reaction was stirred at 25°C for 6 hours. The temperature was then raised to 55°C, and 1,3-propane sultone was slowly added with stirring. The reaction was stirred for 10 hours. The toluene was removed by vacuum rotary evaporation, and the product was dissolved in a 1:1 mixture of water and isopropanol. The product was washed twice with petroleum ether, vacuum rotary evaporation, and recrystallization was performed twice with anhydrous ethanol to obtain a sulfopolyether. The molar ratio of glycidyl butyrate, sodium hydride, and 1,3-propane sultone was 1:0.9:0.9, and the mass-to-volume ratio of the ester alcoholysis product to toluene was 1 g:10 mL.

[0080] S2: Preparation of an anti-see-through modifier: TiO2, ZnO, and CeO2 with particle sizes of 100-500 nm, 50-200 nm, and 100-300 nm, respectively, were immersed in an AgNO3 solution and dried to obtain Ag-doped nanoparticles. The mass ratio of TiO2, ZnO, and CeO2 was 1:0.5:0.5, and the Ag doping level was 5% of the total mass of the TiO2, ZnO, and CeO2.

[0081] Ag-doped nanoparticles were dispersed in propylene glycol, and the hydrolyzed silane coupling agent KH-550 was added. The mixture was stirred and reacted at 70°C for 4 hours. After filtration, the mixture was washed with propylene glycol and dried to obtain an anti-see-through modifier. The amount of silane coupling agent KH-550 was 3% of the total mass of TiO2, ZnO, and CeO2.

[0082] S3: Preparation of modified PTT Terephthalic acid, propylene glycol, an anti-see-through modifier, tetrabutyl titanate, a stabilizer, trimethyl phosphate, and an anti-ether agent, sodium acetate, were added to a beating tank for beating. The mixture was then introduced into an esterification reactor I, where it reacted at 240°C and 60kPa until the acid value reached 13KOH / g. The mixture was then introduced into an esterification reactor II. In esterification reactor II, the mixture first entered chamber I and reacted at 250°C and 20kPa for 60 minutes. The mixture then entered chamber II and mixed with tetrabutyl titanate, reacted at 250°C and 20kPa for 60 minutes, and then entered chamber III and mixed with a sulfopolyether, reacted at 250°C and 20kPa for 60 minutes. The mixture was then introduced into a polycondensation reactor. In the polycondensation reactor, the material is first reacted in chamber 1 at 245°C and 1.1 kPa for 70 minutes, then in chamber 2 at 255°C and 1.15 kPa for 70 minutes, and finally in chamber 3 at 270°C and 125 Pa for 90 minutes. The material is discharged to obtain modified PTT. The molar ratio of terephthalic acid to propylene glycol is 1:1.2; the amount of the anti-see-through modifier is 12% by weight of the modified PTT; the amount of trimethyl phosphate is 0.002% by weight of the modified PTT; the amount of sodium acetate is 0.02% by weight of the modified PTT; the total amount of tetrabutyl titanate is 0.5% by weight of the terephthalic acid (the mass ratio of tetrabutyl titanate added in the beating stage to the esterification stage is 1:9); and the amount of sulfopolyether is 3.5% by weight of the modified PTT.

[0083] S4: Preparation of parallel composite fibers Modified PTT and normal pressure cationic dyeable PET (Hengyi, CDP) with a mass ratio of 1:1 were kept at 130°C for 30 minutes and then spun in parallel, wherein the box temperature of modified PTT was 270°C and the box temperature of normal pressure cationic dyeable PET was 280°C. Subsequently, they were subjected to ring cooling heating, side blowing, and oiling, and then wound at a speed of 4500m / min to obtain PTT / PET parallel composite fibers (75D / 72F FDY).

[0084] S5: Fabric Preparation The PTT / PET parallel composite fibers were woven to obtain a fabric. During the weaving process, a compact spinning process (twist of 900 twists / m) was used to increase the yarn density, and a high-density plain weave structure was selected, with warp density × weft density = 200 × 120 strands / inch.

[0085] Comparative Example 1 The only difference between this comparative example and Example 2 is that, instead of using sulfopolyether, sodium dimethyl sulfoisophthalate (SIPM) and polyethylene glycol (PEG) were used to modify PTT; the remaining steps were the same as those in Example 2. Specifically, the steps for preparing the modified PTT, composite fiber, and fabric in this comparative example are as follows: S1: Preparation of SIPM esterification solution SIPM, propylene glycol, and tetrabutyl titanate are pumped into a preparation tank, heated to 170°C, and water begins to flow. The temperature is then gradually raised to 175°C. Heating is stopped when 85% water flow is achieved, propylene glycol is added for cooling, and the mixture is transferred to a finished product tank. Trimethyl phosphate (stabilizer) and sodium acetate (anti-ether agent) are added to the finished product tank, and propylene glycol is added to prepare a 25% by weight SIPM esterified solution (i.e., the amount of SIPM in this step is 25% by weight of the resulting SIPM esterified solution). The amount of tetrabutyl titanate is 0.003% by weight of SIPM; the amount of SIPM is 2.9% by weight of the modified PTT; the amount of trimethyl phosphate is 0.002% by weight of the modified PTT; and the amount of sodium acetate is 0.02% by weight of the modified PTT.

[0086] S2: Preparation of anti-see-through modifier TiO2, ZnO, and CeO2 with particle sizes of 100-500nm, 50-200nm, and 100-300nm, respectively, were immersed in an AgNO3 solution and dried to produce Ag-doped nanoparticles. The mass ratio of TiO2, ZnO, and CeO2 was 1:0.5:0.5, and the Ag doping level was 5% of the total mass of the TiO2, ZnO, and CeO2.

[0087] Ag-doped nanoparticles were dispersed in propylene glycol, and the hydrolyzed silane coupling agent KH-550 was added. The mixture was stirred and reacted at 70°C for 4 hours. After filtration, the mixture was washed with propylene glycol and dried to obtain an anti-see-through modifier. The amount of silane coupling agent KH-550 was 3% of the total mass of TiO2, ZnO, and CeO2.

[0088] S3: Preparation of modified PTT Terephthalic acid, propylene glycol, tetrabutyl titanate, and anti-see-through modifier are added to a beating tank for beating, and then introduced into an esterification reactor I. After reacting at 240°C and 60kPa until the acid value reaches 13KOH / g, the materials are introduced into an esterification reactor II. In the esterification reactor II, the materials first enter the first chamber, react at 250°C and 20kPa for 60 minutes, then enter the second chamber to mix with tetrabutyl titanate, react at 250°C and 20kPa for 60 minutes, and then enter the third chamber to mix with SIPM esterification liquid and PEG (M w=6000Da) are mixed, reacted at 250°C and 20kPa for 60 minutes, and then injected into a polycondensation reactor. In the polycondensation reactor, the material is first reacted in the first chamber at 245°C and 1.1kPa for 70 minutes, then enters the second chamber at 255°C and 1.15kPa for 70 minutes, and finally enters the third chamber at 270°C and 125Pa for 90 minutes, and the material is discharged to obtain modified PTT. Among them, the molar ratio of terephthalic acid and propylene glycol (the total amount of propylene glycol in steps S1 and S3) is 1:1.2; the amount of anti-see-through modifier is 12% of the mass of the modified PTT; the total amount of tetrabutyl titanate is 0.5% of the mass of terephthalic acid (the mass ratio of tetrabutyl titanate added in the beating stage and the esterification stage is 1:9); the amount of PEG is 3.5% of the mass of the modified PTT.

[0089] S4: Preparation of parallel composite fibers Modified PTT and normal pressure cationic dyeable PET (Hengyi, CDP) with a mass ratio of 1:1 were kept at 130°C for 30 minutes and then spun in parallel, wherein the box temperature of modified PTT was 270°C and the box temperature of normal pressure cationic dyeable PET was 280°C. Subsequently, they were subjected to ring cooling heating, side blowing, and oiling, and then wound at a speed of 4500m / min to obtain PTT / PET parallel composite fibers (75D / 72F FDY).

[0090] S5: Fabric Preparation The PTT / PET parallel composite fibers were woven to obtain a fabric. During the weaving process, a compact spinning process (twist of 900 twists / m) was used to increase the yarn density, and a high-density plain weave structure was selected, with warp density × weft density = 200 × 120 strands / inch.

[0091] Comparative Example 2 The only difference between this comparative example and Example 1 is that in step S2, TiO2, ZnO and CeO2 are replaced with equal masses of TiO2; the remaining steps are the same as in Example 1. Specifically, the steps for preparing modified PTT, composite fibers and fabrics in this comparative example are as follows: S1: Preparation of sulfopolyether Take triisobutylaluminum, phosphoric acid and DBU in a molar ratio of 1:0.35:0.25. Dissolve triisobutylaluminum in toluene to prepare a 1 mol / L solution I; dissolve phosphoric acid in ether to prepare a 1 mol / L solution II. After replacing the air in the reactor with dry nitrogen, add solution I into the reactor, and then add solution II dropwise at 0°C with stirring. After the addition is complete, continue stirring and mixing for 15 minutes, then add DBU, and stir at 45°C for 3 hours to obtain a ring-opening polymerization catalyst solution.

[0092] After replacing the air in the polymerization reactor with dry nitrogen, ethylene oxide and toluene were added to the polymerization reactor, and then the ring-opening polymerization catalyst solution was added and stirred at 25°C until the reaction temperature reached M. w When the concentration reaches 510Da, glycidyl butyrate was added and the reaction was continued at 25°C with stirring until the reaction temperature reached M w After reaching 5037 Da, n-hexane was added to precipitate the product, which was then filtered to obtain a ring-opening copolymerization product. The molar ratio of ethylene oxide to glycidyl butyrate was 1:0.1; the amount of ring-opening polymerization catalyst used was 9% of the mass of ethylene oxide; and the mass-to-volume ratio of ethylene oxide to toluene was 1 g:10 mL.

[0093] Add the ring-opening copolymerization product, TBD, and methanol to an ester alcoholysis reactor and stir at 25°C for 10 hours. Add tetrahydrofuran to precipitate the product, then filter to obtain the ester alcoholysis product. The TBD content is 4% of the mass of the ring-opening copolymerization product, and the mass-to-volume ratio of the ring-opening copolymerization product to methanol is 1 g:10 mL.

[0094] The ester alcoholysis product and toluene were added to a sulfonation reactor. After complete dissolution, sodium hydride was slowly added with stirring. The reaction was stirred at 25°C for 6 hours. The temperature was then raised to 55°C, and 1,3-propane sultone was slowly added with stirring. The reaction was stirred for 10 hours. The toluene was removed by vacuum rotary evaporation, and the product was dissolved in a 1:1 mixture of water and isopropanol. The product was washed twice with petroleum ether, vacuum rotary evaporation, and recrystallization was performed twice with anhydrous ethanol to obtain a sulfopolyether. The molar ratio of glycidyl butyrate, sodium hydride, and 1,3-propane sultone was 1:0.7:0.7, and the mass-to-volume ratio of the ester alcoholysis product to toluene was 1 g:10 mL.

[0095] S2: Preparation of anti-see-through modifier TiO2 with a particle size of 100-500nm is immersed in a AgNO3 solution and dried to obtain Ag-doped nanoparticles, wherein the Ag doping amount is 5% of the mass of the TiO2.

[0096] Ag-doped nanoparticles were dispersed in propylene glycol, and the hydrolyzed silane coupling agent KH-550 was added. The mixture was stirred and reacted at 70°C for 4 hours. After filtration, the mixture was washed with propylene glycol and dried to obtain an anti-see-through modifier. The amount of silane coupling agent KH-550 was 3% of the mass of the TiO2.

[0097] S3: Preparation of modified PTT Terephthalic acid, propylene glycol, an anti-see-through modifier, tetrabutyl titanate, a stabilizer, trimethyl phosphate, and an anti-ether agent, sodium acetate, were added to a beating tank for beating. The mixture was then introduced into an esterification reactor I, where it reacted at 240°C and 60kPa until the acid value reached 13KOH / g. The mixture was then introduced into an esterification reactor II. In esterification reactor II, the mixture first entered chamber I and reacted at 250°C and 20kPa for 60 minutes. The mixture then entered chamber II and mixed with tetrabutyl titanate, reacted at 250°C and 20kPa for 60 minutes, and then entered chamber III and mixed with a sulfopolyether, reacted at 250°C and 20kPa for 60 minutes. The mixture was then introduced into a polycondensation reactor. In the polycondensation reactor, the materials were first reacted in the first chamber at 245°C and 1.1 kPa for 70 minutes, then in the second chamber at 255°C and 1.15 kPa for 70 minutes, and finally in the third chamber at 270°C and 125 Pa for 90 minutes. The modified PTT was discharged. The molar ratio of terephthalic acid to propylene glycol was 1:1.2; the amount of the anti-see-through modifier was 12% by weight of the modified PTT; the amount of trimethyl phosphate was 0.002% by weight of the modified PTT; the amount of sodium acetate was 0.02% by weight of the modified PTT; the total amount of tetrabutyl titanate was 0.5% by weight of the terephthalic acid (the mass ratio of tetrabutyl titanate added in the beating stage to the esterification stage was 1:9); and the amount of sulfopolyether was 7% by weight of the modified PTT.

[0098] S4: Preparation of parallel composite fibers Modified PTT and normal pressure cationic dyeable PET (Hengyi, CDP) with a mass ratio of 1:1 were kept at 130°C for 30 minutes and then spun in parallel, wherein the box temperature of modified PTT was 270°C and the box temperature of normal pressure cationic dyeable PET was 280°C. Subsequently, they were subjected to ring cooling heating, side blowing, and oiling, and then wound at a speed of 4500m / min to obtain PTT / PET parallel composite fibers (75D / 72F FDY).

[0099] S5: Fabric Preparation The PTT / PET parallel composite fibers were woven to obtain a fabric. During the weaving process, a compact spinning process (twist of 900 twists / m) was used to increase the yarn density, and a high-density plain weave structure was selected, with warp density × weft density = 200 × 120 strands / inch.

[0100] Comparative Example 3 The only difference between this comparative example and Example 1 is that in step S2, TiO2, ZnO and CeO2 are not modified by Ag doping; the remaining steps are the same as in Example 1. Specifically, the steps for preparing modified PTT, composite fibers and fabrics in this comparative example are as follows: S1: Preparation of sulfopolyether Take triisobutylaluminum, phosphoric acid and DBU in a molar ratio of 1:0.35:0.25. Dissolve triisobutylaluminum in toluene to prepare a 1 mol / L solution I; dissolve phosphoric acid in ether to prepare a 1 mol / L solution II. After replacing the air in the reactor with dry nitrogen, add solution I to the reactor, and then add solution II dropwise at 0°C with stirring. After the addition is complete, continue stirring and mixing for 15 minutes, then add DBU, and stir at 45°C for 3 hours to obtain a ring-opening polymerization catalyst solution.

[0101] After replacing the air in the polymerization reactor with dry nitrogen, ethylene oxide and toluene were added to the polymerization reactor, and then the ring-opening polymerization catalyst solution was added and stirred at 25°C until the reaction temperature reached M. w When the concentration reaches 510Da, glycidyl butyrate was added and the reaction was continued at 25°C with stirring until the reaction temperature reached M w After reaching 5037 Da, n-hexane was added to precipitate the product, which was then filtered to obtain a ring-opening copolymerization product. The molar ratio of ethylene oxide to glycidyl butyrate was 1:0.1; the amount of ring-opening polymerization catalyst used was 9% of the mass of ethylene oxide; and the mass-to-volume ratio of ethylene oxide to toluene was 1 g:10 mL.

[0102] Add the ring-opening copolymerization product, TBD, and methanol to an ester alcoholysis reactor and stir at 25°C for 10 hours. Add tetrahydrofuran to precipitate the product, then filter to obtain the ester alcoholysis product. The TBD content is 4% of the mass of the ring-opening copolymerization product, and the mass-to-volume ratio of the ring-opening copolymerization product to methanol is 1 g:10 mL.

[0103] The ester alcoholysis product and toluene were added to a sulfonation reactor. After complete dissolution, sodium hydride was slowly added with stirring. The reaction was stirred at 25°C for 6 hours. The temperature was then raised to 55°C, and 1,3-propane sultone was slowly added with stirring. The reaction was stirred for 10 hours. The toluene was removed by vacuum rotary evaporation, and the product was dissolved in a 1:1 mixture of water and isopropanol. The product was washed twice with petroleum ether, vacuum rotary evaporation, and recrystallization was performed twice with anhydrous ethanol to obtain a sulfopolyether. The molar ratio of glycidyl butyrate, sodium hydride, and 1,3-propane sultone was 1:0.7:0.7, and the mass-to-volume ratio of the ester alcoholysis product to toluene was 1 g:10 mL.

[0104] S2: Preparation of an anti-see-through modifier: TiO2, ZnO, and CeO2 with particle sizes of 100-500 nm, 50-200 nm, and 100-300 nm, respectively, were dispersed in propylene glycol. The hydrolyzed silane coupling agent KH-550 was added and stirred at 70°C for 4 hours. The mixture was filtered, washed with propylene glycol, and dried to obtain an anti-see-through modifier. The mass ratio of TiO2, ZnO, and CeO2 was 1:0.5:0.5, and the amount of silane coupling agent KH-550 was 3% of the total mass of TiO2, ZnO, and CeO2.

[0105] S3: Preparation of modified PTT Terephthalic acid, propylene glycol, an anti-see-through modifier, tetrabutyl titanate, a stabilizer, trimethyl phosphate, and an anti-ether agent, sodium acetate, were added to a beating tank for beating. The mixture was then introduced into an esterification reactor I, where it reacted at 240°C and 60kPa until the acid value reached 13KOH / g. The mixture was then introduced into an esterification reactor II. In esterification reactor II, the mixture first entered chamber I and reacted at 250°C and 20kPa for 60 minutes. The mixture then entered chamber II and mixed with tetrabutyl titanate, reacted at 250°C and 20kPa for 60 minutes, and then entered chamber III and mixed with a sulfopolyether, reacted at 250°C and 20kPa for 60 minutes. The mixture was then introduced into a polycondensation reactor. In the polycondensation reactor, the materials were first reacted in the first chamber at 245°C and 1.1 kPa for 70 minutes, then in the second chamber at 255°C and 1.15 kPa for 70 minutes, and finally in the third chamber at 270°C and 125 Pa for 90 minutes. The modified PTT was discharged. The molar ratio of terephthalic acid to propylene glycol was 1:1.2; the amount of the anti-see-through modifier was 12% by weight of the modified PTT; the amount of trimethyl phosphate was 0.002% by weight of the modified PTT; the amount of sodium acetate was 0.02% by weight of the modified PTT; the total amount of tetrabutyl titanate was 0.5% by weight of the terephthalic acid (the mass ratio of tetrabutyl titanate added in the beating stage to the esterification stage was 1:9); and the amount of sulfopolyether was 7% by weight of the modified PTT.

[0106] S4: Preparation of parallel composite fibers Modified PTT and normal pressure cationic dyeable PET (Hengyi, CDP) with a mass ratio of 1:1 were kept at 130°C for 30 minutes and then spun in parallel, wherein the box temperature of modified PTT was 270°C and the box temperature of normal pressure cationic dyeable PET was 280°C. Subsequently, they were subjected to ring cooling heating, side blowing, and oiling, and then wound at a speed of 4500m / min to obtain PTT / PET parallel composite fibers (75D / 72F FDY).

[0107] S5: Fabric Preparation The PTT / PET parallel composite fibers were woven to obtain a fabric. During the weaving process, a compact spinning process (twist of 900 twists / m) was used to increase the yarn density, and a high-density plain weave structure was selected, with warp density × weft density = 200 × 120 strands / inch.

[0108] Test Case The fabrics prepared in each embodiment and comparative example were dyed with cationic dyes at normal pressure, and the dyeing saturation value was detected. The dyeing conditions were as follows: the dye was methylene blue, the bath ratio was 1:100, the temperature was 100°C, and the time was 4 hours; the dye solution formula was as follows: the dye was methylene blue, the dye concentration was 5% owf, the dye solution pH was 4.5, and acetic acid was 1%.

[0109] The fabrics prepared in each embodiment and comparative example were taken and the anti-see-through index was tested with reference to GB / T 42698-2023 Testing and evaluation of anti-see-through properties of textiles.

[0110] The test results of the normal pressure cationic dyeability and anti-see-through performance of the fabric are shown in Table 1.

[0111] Table 1 Test results of normal pressure cationic dyeability and anti-see-through performance Cationic dyeing saturation value Anti-perspective index Example 1 6.2 96.7 Example 2 5.0 96.9 Example 3 3.9 96.2 Example 4 4.3 96.3 Comparative Example 1 3.5 97.4 Comparative Example 2 6.2 94.0 Comparative Example 3 6.4 93.6 Analyzing the test results in Table 1, we can see that: (1) Compared with Comparative Example 1, the cationic dyeing saturation values ​​of Examples 1-4 are improved, indicating that compared with the conventional method of introducing SIPM and PEG into the PTT molecular chain, the present invention connects the sulfonic acid group to the polyether molecular chain, which can improve the cationic dyeability of the modified PTT to a greater extent. The reason for this is that by connecting the sulfonic acid group to the polyether molecular chain, the flexible polyether chain segment can be used to form an amorphous region with strong molecular chain mobility in the modified PTT, which is conducive to the entry of cationic dyes. The sulfonic acid group in the region is then used to combine with the cationic dye and fix it in the modified PTT. In this way, the polyether segment and the sulfonic acid group can better cooperate with each other, thereby improving the cationic dyeability of PTT to a greater extent. In addition, in the process of introducing the sulfonic acid group into the polyether molecular chain, an appropriate amount of side chains will be formed on the polyether molecular chain, which is conducive to forming more pores in the amorphous region of the modified PTT, which also helps to improve the cationic dyeability of the modified PTT.

[0112] (2) The cationic dyeing saturation value of Example 2 is higher than that of Example 3, indicating that compared with directly copolymerizing ethylene oxide and glycidyl butyrate, the present invention, by prepolymerizing ethylene oxide first and then adding glycidyl butyrate for copolymerization, can impart better cationic dyeability to the modified PTT. The reason for this is that the method of the present invention helps to maintain a certain distance between adjacent side chain hydroxyl groups in the copolyether, thereby resulting in a flexible chain segment of a certain length in the portion connected to the PTT molecular chain, which is conducive to the formation of amorphous regions with strong molecular chain mobility in the modified PTT.

[0113] (3) The cationic dyeing saturation value of Example 4 is lower than that of Example 2, indicating that in the process of synthesizing the copolyether, when the proportion of glycidyl butyrate in the two monomers is too large, the cationic dyeability of the modified PTT will decrease. This may be because the introduction of too many side chains in the polyether limits the molecular chain mobility of the polyether segment.

[0114] (4) The anti-see-through index of Example 1 is higher than that of Comparative Example 2, indicating that compared with the use of TiO2 alone, the present invention uses a compound of TiO2, ZnO and CeO2 to give the fabric better anti-see-through performance. This may be because the compound of TiO2, ZnO and CeO2 can cover a wider light absorption band.

[0115] (4) The anti-see-through index of Example 1 is higher than that of Comparative Example 3, indicating that the present invention can improve the anti-see-through performance of the fabric by modifying TiO2, ZnO and CeO2 with Ag doping. This may be because Ag doping can form a surface plasmon resonance effect, thereby improving the light absorption capacity.

[0116] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this disclosure pertains. Unless otherwise specified, the raw materials and equipment used herein are conventional in the art and can be obtained from conventional commercial sources. The methods used herein are conventional in the art, unless otherwise specified.

[0117] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a normal pressure cationic dyeable modified PTT, characterized in that: include: S1: After ring-opening copolymerization of ethylene oxide and glycidyl butyrate, ester hydrolysis and hydroxyl sulfonation are carried out in sequence to obtain a sulfopolyether containing at least two hydroxyl groups; S2: Copolymerizing terephthalic acid, propylene glycol and sulfopolyether to obtain normal pressure cationic dyeable modified PTT.

2. The preparation method according to claim 1, characterized in that In step S1, the molar ratio of ethylene oxide to glycidyl butyrate is 1:0.1-0.

2.

3. The preparation method according to claim 1 or 2, characterized in that In step S1, the process of ring-opening copolymerization of ethylene oxide and glycidyl butyrate includes: pre-polymerizing ethylene oxide to a weight-average molecular weight of 500-800 Da, adding glycidyl butyrate, and ring-opening polymerization to a weight-average molecular weight of 5000-6000 Da.

4. The preparation method according to claim 1, characterized in that In step S1, the hydroxyl sulfonation process includes: performing a sodiumization reaction on the ester alcoholysis product with sodium hydride, and then performing a sulfonation reaction with 1,3-propane sultone; the molar ratio of glycidyl butyrate, sodium hydride and 1,3-propane sultone is 1:0.7-0.9:0.7-0.

9.

5. The preparation method according to claim 1, characterized in that In step S2, the amount of the sulfopolyether is 3.5-7% of the mass of the normal pressure cationic dyeable modified PTT.

6. The preparation method according to claim 1, characterized in that In step S2, before copolymerizing terephthalic acid, propylene glycol and sulfopolyether, an anti-see-through modifier is mixed in; the anti-see-through modifier includes TiO2, ZnO and CeO2, which are doped with Ag and have a silane coupling agent grafted on the surface.

7. The preparation method according to claim 6, characterized in that The doping amount of Ag is 2-8% of the total mass of TiO2, ZnO and CeO2; the amount of the silane coupling agent is 1-5% of the total mass of TiO2, ZnO and CeO2.

8. The preparation method according to claim 1, characterized in that In step S2, the molar ratio of terephthalic acid to propylene glycol is 1:1.2-1.

8.

9. The preparation method according to claim 1, characterized in that The specific process of step S2 includes: mixing terephthalic acid, propylene glycol and the first part of the catalyst, reacting at 235-245°C and 60-65kPa until the acid value reaches 10-18KOH / g, then reacting at 245-258°C and 20-25kPa for 60-70min, adding the second part of the catalyst, reacting at 240-258°C and 20-25kPa for 60-70min, adding the sulfopolyether, reacting at 250-255°C and 20-25kPa for 60-70min, reacting at 238-248°C and 1.1-1.15kPa for 60-80min, reacting at 248-260°C and 1.1-1.2kPa for 60-80min, and reacting at 260-275°C and 115-135Pa for 60-120min.

10. Application of normal pressure cationic dyeable modified PTT in composite fibers, characterized in that: The composite fiber is a parallel composite fiber of PET and normal pressure cationically dyeable modified PTT; the normal pressure cationically dyeable modified PTT is prepared by the preparation method according to any one of claims 1 to 9.