A method for preparing anti-shrinkage polyester fiber

Abstract

This invention relates to the field of spinning technology and discloses a method for preparing anti-shrinkage polyester fiber, comprising: (1) preparing an anti-shrinkage functional composite alcohol solution; (2) mixing terephthalic acid, the anti-shrinkage functional composite alcohol solution, and a catalyst, followed by esterification, polycondensation, discharge, and slicing to obtain anti-shrinkage functional copolyester chips; (3) melt spinning, corona treatment, oiling, cooling, stretching, and heat setting to obtain anti-shrinkage polyester fiber. On the one hand, this invention introduces polycaprolactone diol and pentanediol into polyester to improve its anti-shrinkage properties; on the other hand, this invention adds inorganic nanomaterials to the oiling agent and attaches them to the fiber surface during the oiling stage. This method not only eliminates the granulation process and enables continuous production of this fiber, but also does not affect the spinnability of the polyester fiber; this method makes the inorganic nanomaterials mainly concentrated on the surface of the polyester fiber, resulting in better anti-shrinkage properties.

Description

Technical Field

[0001] This invention relates to the field of spinning technology, and more particularly to a method for preparing anti-shrinkage polyester fiber. Background Technology

[0002] Polyester fiber, as a common synthetic fiber, possesses many excellent properties, such as abrasion resistance, wrinkle resistance, and ease of care, leading to its wide application in textiles and other fields. However, traditional polyester fibers often shrink during heat treatment or washing, resulting in dimensional instability, deformation, or warping of textiles. This shrinkage is usually caused by the crystallinity and heat shrinkage of polyester fibers, causing numerous inconveniences in textile production and use, and reducing product quality and stability. To address this issue, much research has been dedicated to developing shrink-resistant polyester fibers, some of which involve adding specific anti-shrinkage agents or employing special spinning and finishing processes. However, these methods often suffer from high costs, complex processes, significant environmental impact, and poor wash resistance.

[0003] Incorporating inorganic nanomaterials into fabrics can improve their shrinkage resistance. Inorganic nanomaterials are substances with good heat resistance and abrasion resistance, as well as good softness and elasticity. When inorganic nanomaterials are combined with fabric fibers, they can increase the fabric's tensile strength and deformation resistance, thereby reducing the degree of shrinkage during washing or wearing. In addition, they can also improve the fabric's abrasion resistance and durability, extending its service life.

[0004] For example, patent CN201210294818 discloses the following technology: surface modification of nano-silica is performed using silane coupling agent γ-aminopropyltriethoxysilane, dry polylactic acid particles are mixed with modified nano-silica, and polylactic acid + silica masterbatch is produced by twin-screw extruder. The masterbatch and polylactic acid particles are mixed evenly according to the weight ratio, and then added to a melt spinning machine for spinning. After two-zone stretching, polylactic acid + silica fiber is produced. The polylactic acid filaments prepared by this method have good heat resistance and excellent mechanical properties.

[0005] However, the above solution has the following drawbacks: ① It requires an additional granulation process and the addition of masterbatch during spinning, which requires an additional masterbatch addition device, making the process complicated and the production investment large; ② The addition ratio of masterbatch needs to be strictly controlled during the addition process, which can easily cause uneven mixing, resulting in poor compatibility between the masterbatch and the resin matrix, poor spinnability of the resin melt, and problems such as broken monofilaments, fuzzy filaments, and low strength during spinning. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for preparing anti-shrinkage polyester fibers. On one hand, this invention introduces polycaprolactone diol and pentanediol as modifying monomers into the polyester, which improves the polyester's anti-shrinkage properties. On the other hand, this invention adds inorganic nanomaterials to the oiling agent and attaches them to the fiber surface during the oiling stage. First, this method not only eliminates the need for granulation, enabling continuous fiber production, but also does not affect the spinnability of the polyester fiber. Second, this method ensures that the inorganic nanomaterials are mainly concentrated on the surface of the polyester fiber, resulting in better anti-shrinkage properties compared to when they are dispersed within the fiber. Furthermore, this invention subjects the nascent fibers to corona treatment before oiling, which increases the number of active sites on the fiber surface, thereby enhancing the interfacial bonding between the inorganic nanoparticles and the polyester fiber.

[0007] The specific technical solution of this invention is: a method for preparing anti-shrinkage polyester fiber, comprising the following steps:

[0008] (1) Prepare a mixed solution of ethylene glycol, polycaprolactone diol and pentanediol by mixing them in a molar ratio of (75-85): (10-15): (15-10) to obtain an anti-shrinkage composite alcohol solution.

[0009] (2) Terephthalic acid, anti-shrinkage functional composite alcohol solution and catalyst are mixed and added to the reaction vessel for esterification, polycondensation, discharge and slicing to obtain anti-shrinkage functional copolyester slices.

[0010] (3) The anti-shrinkage functional copolyester chips are melt-spun, the resulting nascent fibers are corona-treated, and then oiled, cooled, stretched and heat-set to obtain anti-shrinkage polyester fibers; the solvent for oiling contains inorganic nanomaterials and silane coupling agents; the inorganic nanomaterials include one or more of zirconium oxide, boron nitride and silicon carbide with a particle size distribution of 10-100 nm.

[0011] To improve the shrinkage resistance of polyester fibers, this invention optimizes the process from the following two aspects:

[0012] On the one hand, the present invention introduces polycaprolactone diol and pentanediol as modifying monomers in the polyester synthesis process, which can not only improve the softness and extensibility of polyester, but also affect the crystal structure of polyester, making it more uniform or less prone to crystallization. By increasing the chain length and molecular weight of polyester, the heat resistance and solvent resistance of polyester are further improved, so that polyester has excellent shrinkage.

[0013] On the other hand, the present invention adds inorganic nanomaterials to the oiling agent, that is, it changes the addition from the granulation stage in the prior art to the oiling stage. The advantages are as follows: First, the method of the present invention not only eliminates the granulation process and enables continuous production of this fiber, but also ensures that the spinnability of the polyester melt is not negatively affected during the spinning process because the polyester melt does not contain inorganic nanomaterials. Inorganic nanomaterials not only change the rheological properties of the polymer, but also easily clog the spinneret orifice. The present invention avoids the above problems by compounding inorganic nanomaterials into the fiber after obtaining the nascent fiber. Secondly, compared with adding inorganic nanomaterials during the granulation process, the addition method of this invention has a better effect on the anti-shrinkage modification of polyester fibers. This is because: existing technologies add inorganic nanomaterials to the polyester before spinning, resulting in the inorganic nanomaterials being dispersed within the fiber itself after spinning; however, this invention adds inorganic nanomaterials to the oiling agent during the oiling step after the nascent fiber is first formed. The inorganic nanomaterials adhere uniformly to the surface of the nascent fiber along with the oiling agent. Then, during subsequent cooling, stretching, and heat setting processes, the inorganic nanomaterials gradually migrate to the fiber surface. Specifically, the inorganic nanomaterials adhere uniformly to the surface of the nascent fiber along with the oiling agent. In this process, the oiling agent acts as a carrier, transporting the inorganic nanomaterials to the fiber surface. During subsequent heating and heat setting processes, due to the increase in temperature and fiber stretching, the inorganic nanomaterials on the fiber surface begin to migrate. During this process, the inorganic nanomaterials gradually migrate from the fiber to the fiber surface through diffusion, sliding, and other means.

[0014] Therefore, in the polyester fiber obtained by this invention, the inorganic nanomaterials are mainly concentrated on the fiber surface, exhibiting better shrinkage resistance and other properties compared to those dispersed within the fiber. This is because the compatibility between inorganic nanomaterials and polyester is limited, and even with surface modification treatment, it is difficult to ensure highly uniform dispersion of the inorganic nanomaterials within the polyester. The invention team discovered that during fiber production, internal stress is generated within the fiber due to intermolecular forces and thermal motion. When the distribution of inorganic nanomaterials within the fiber is not uniform, the internal stress becomes more concentrated, affecting the fiber's shrinkage resistance. Furthermore, uneven distribution of inorganic nanomaterials can lead to uneven intermolecular forces in certain regions, causing disordered molecular arrangement and generating additional internal stress. These additional internal stresses interact with the existing internal stress, affecting the fiber's shrinkage resistance. In addition, the inorganic nanomaterials within the fiber also influence the fiber's shrinkage resistance by affecting its internal thermal motion. When the distribution of inorganic nanomaterials within a fiber is not uniform, the thermal motion within the fiber is disturbed, thus affecting the fiber's shrinkage resistance. This invention cleverly concentrates inorganic nanomaterials primarily on the fiber surface. Compared to existing technologies, this not only overcomes the aforementioned problems but also significantly improves the fiber's fracture resistance, abrasion resistance, wrinkle resistance, and weather resistance. Fracture resistance: Inorganic nanomaterials dispersed on the fiber surface significantly enhance the fiber's fracture resistance. In contrast, internally dispersed inorganic nanomaterials are less effective in improving fracture resistance. Abrasion resistance and wrinkle resistance: Inorganic nanomaterials dispersed on the fiber surface effectively increase the fiber's surface hardness and smoothness, thereby enhancing its abrasion resistance and wrinkle resistance. In contrast, while internally dispersed inorganic nanomaterials can also improve fiber strength and toughness, their improvement on surface abrasion resistance and wrinkle resistance is limited. The inorganic nanomaterials dispersed on the fiber surface can form a protective film, reducing the direct interaction between the fiber and external environmental factors (such as ultraviolet radiation and moisture), thus enhancing the fiber's UV resistance and weather resistance. In contrast, internally dispersed inorganic nanomaterials are less resistant to external environmental factors.

[0015] Furthermore, the present invention performs corona treatment on the nascent fibers before oiling. This treatment can increase the number of active sites on the fiber surface, which can react with the silane coupling agent in the oiling agent, thereby making it easier for the fibers to combine with inorganic nanomaterials and enhancing the interfacial bonding force between them.

[0016] Furthermore, this invention also reveals that the particle size of the inorganic nanomaterials is crucial to the performance of polyester fibers. If the particle size is too small, it possesses high surface energy, making it prone to aggregation and precipitation, resulting in uneven distribution and easy detachment on the fiber surface. Moreover, as the particle size decreases, the surface effect gradually weakens, reducing its surface properties and protective capabilities against the fiber. Conversely, excessively large particle sizes also reduce the surface properties and protective capabilities against the fiber. Ultimately, this invention preferably uses a particle size of 10-100 nm.

[0017] Preferably, in step (1), the molar ratio of ethylene glycol, polycaprolactone diol, and pentanediol is (77-83):(11-14):(12-10).

[0018] This invention reveals that the content of polycaprolactone diol and pentanediol is crucial for the modification effect. For polycaprolactone diol, an excessive proportion will excessively lower the melting point and thermal stability of the polyester, easily altering its physical properties; conversely, an insufficient proportion will affect the polyester's thermal stability and processing performance. For pentanediol, since it is a hard segment unit, an excessive proportion will increase the polyester's hardness, affecting its flexibility and processing performance; simultaneously, overly hard segments may reduce the polyester's heat resistance and chemical resistance. Conversely, an insufficient proportion will relatively increase the proportion of soft segments, leading to a decrease in the polyester's hardness and affecting its mechanical properties; furthermore, an insufficient number of hard segments may also reduce the polyester's heat resistance and chemical resistance. In summary, both excessive and insufficient proportions of polycaprolactone diol and pentanediol will adversely affect the polyester's performance. Therefore, during polyester synthesis, it is necessary to precisely control the proportions of these monomers to obtain optimal performance.

[0019] Preferably, in step (2), the catalyst is a mixed catalyst composed of antimony acetate and antimony trioxide in a mass ratio of 1:(1.5 to 2.5), and the total amount is 0.05 to 0.1 wt% of terephthalic acid, more preferably 0.06 to 0.08%.

[0020] Preferably, in step (2), the esterification temperature is controlled at 220-245°C and the pressure is controlled at 0.18-0.24 MPa; more preferably, the temperature is controlled at 225-240°C and the pressure is controlled at 0.20-0.23 MPa.

[0021] Preferably, in step (2), the temperature of the polycondensation is controlled at 270-290°C, more preferably 278-288°C, and vacuuming begins after the temperature inside the reactor reaches the set value, with the vacuum degree controlled within 80 Pa.

[0022] Preferably, in step (2), the intrinsic viscosity of the anti-shrinkage functional copolyester chips is 0.64 to 0.70 dL / g, and more preferably 0.66 to 0.68 dL / g.

[0023] Preferably, in step (3), the corona power is controlled at 1 to 5 kW, and more preferably 2 to 4 kW.

[0024] Preferably, in step (3), the particle size distribution of the inorganic nanomaterial is 20-80 nm.

[0025] Preferably, in step (3), the silane coupling agent includes one or more of vinylsilane, aminosilane, and methacryloxysilane, and is more preferably vinylsilane.

[0026] Preferably, in step (3), during the melt spinning process, the temperature of the screw heating zone is 250-260℃, 255-270℃, 265-280℃, 275-290℃, and 285-298℃, respectively; more preferably, it is 253-257℃, 259-269℃, 267-277℃, 280-289℃, and 286-298℃.

[0027] Preferably, in step (3), the cooling is a cooling air blowing method, which can be side blowing, ring blowing, or center radiation blowing.

[0028] Preferably, in step (3), the stretching temperature is 115-150℃ and the stretching ratio is 4-7; more preferably, the stretching temperature is 118-140℃ and the stretching ratio is 5-6. The heat setting temperature is 150-165℃, more preferably 158-162℃.

[0029] This invention discovers that, because inorganic nanomaterials are attached to the fiber surface during the oiling process, conventional drawing and heat-setting processes cannot effectively migrate and disperse these nanomaterials to the fiber surface. Therefore, this invention optimizes the drawing and heat-setting processes to suit the properties of fibers with attached inorganic nanomaterials. Specifically, it appropriately increases the drawing and heat-setting temperatures (conventional drawing and heat-setting temperatures are typically 90-100℃ and 125-135℃, respectively) and increases the draw ratio (conventional draw ratio is around 2 times). Specifically, ① temperature affects the adsorption and diffusion behavior of inorganic nanomaterials on the fiber surface. At appropriately high temperatures, the adsorption of inorganic nanomaterials on the fiber surface is stronger, and their diffusion behavior is also more active. This facilitates a more uniform distribution of inorganic nanomaterials on the fiber surface. ② Regarding the draw ratio: During the drawing process, the inorganic nanomaterials interact with the molecular structure of the nascent fiber, forming a reinforcing effect. Simultaneously, the addition of inorganic nanomaterials affects the fiber morphology. During the drawing process, inorganic nanomaterials migrate along with the fiber. If the draw ratio is too high, the distribution of inorganic nanomaterials becomes too dispersed, affecting the fiber's shrinkage resistance; conversely, if the draw ratio is too low, it affects the fiber's hand feel, thus impacting comfort. Therefore, it is necessary to select an appropriate draw ratio during the drawing process to balance fiber performance and hand feel, while carefully controlling the migration and distribution of inorganic materials.

[0030] Preferably, in step (3), the interface of the anti-shrinkage polyester fiber is a circular cross-section or an irregular cross-section (such as triangular, trilobal, etc.).

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] (1) In the process of polyester synthesis, the present invention introduces polycaprolactone diol and pentanediol as modified monomers, which can not only improve the softness and extensibility of polyester, but also affect the crystal structure of polyester, making it more uniform or less prone to crystallization. By increasing the chain length and molecular weight of polyester, the heat resistance and solvent resistance of polyester are further improved, so that polyester has excellent shrinkage.

[0033] (2) In this invention, inorganic nanomaterials are added to the oiling agent, allowing them to adhere to the fiber surface during the oiling stage. First, the method of this invention not only eliminates the granulation process, enabling continuous production of this fiber, but also does not affect the spinnability of the polyester fiber. Second, in the final polyester fiber obtained by this invention, the inorganic nanomaterials are mainly concentrated on the fiber surface, exhibiting better shrinkage resistance compared to when they are dispersed inside the fiber.

[0034] (3) The present invention performs corona treatment on the nascent fibers before oiling. This treatment can increase the number of active sites on the fiber surface, which can react with the silane coupling agent in the oil, thereby making it easier for the fibers to combine with inorganic nanomaterials and enhancing the interfacial bonding force between them.

[0035] (4) By optimizing the stretching and heat setting processes, the present invention enables inorganic nanomaterials to migrate to the fiber surface better, thereby further improving the fiber’s anti-shrinkage and other properties. Detailed Implementation

[0036] The present invention will be further described below with reference to embodiments.

[0037] Example 1

[0038] (1) Prepare a solution of ethylene glycol, polycaprolactone diol and pentanediol in a molar ratio of 77:11:12, and take 1.2 mol of the anti-shrinkage composite alcohol solution.

[0039] (2) Take 1 mol of terephthalic acid, and antimony acetate / antimony trioxide mixed catalyst at a weight ratio of 1:2, with a total amount of 0.08% of terephthalic acid. Add terephthalic acid, anti-shrinkage functional composite alcohol solution, and antimony acetate / antimony trioxide mixed catalyst to the reactor. Turn on the stirring and heating device, set the temperature to 230℃, and control the pressure at 0.20 MPa. When the column top temperature rises to 90℃, the esterification reaction is in progress. When the column top temperature drops below 40℃, the esterification is complete when water is released from the reactor and theoretically obtained. Adjust the reactor temperature to 281℃. After the reactor temperature reaches the set value, start vacuuming. Control the vacuum degree to within 80 Pa. When the stirring power of the reactor increases, the polycondensation reaction begins. The synthesis ends when the target stirring power is reached. Discharge the copolymer, cool it with cooling water, slice it, and dry it at 140℃ for 24 hours to obtain anti-shrinkage functional copolyester chips with an intrinsic viscosity of 0.68 dL / g.

[0040] (3) Polyester chips are melt-spun and corona treatment is performed before oiling the nascent fibers. The power is set to 2KW. TF-719 oil containing 3% vinyl silane and 5% zirconium oxide with a particle size distribution of 20-40nm is used for oiling. Side blowing is used for cooling. The winding speed is 1500m / min, the stretching temperature is 129℃, the stretching ratio is 5, and the heat setting temperature is 158℃ to obtain shrink-resistant polyester fibers.

[0041] (4) Take 1m of the obtained anti-shrinkage polyester fiber and ordinary polyester fiber respectively, place them in an environment of 130℃ for 2 hours, record the length after shrinkage, repeat 50 times, take them out and measure the shrinkage rate of ordinary polyester fiber is 2.81% and the shrinkage rate of anti-shrinkage polyester fiber is 0.51%.

[0042] Example 2

[0043] (1) Prepare a solution of ethylene glycol, polycaprolactone diol and pentanediol in a molar ratio of 78:11:11, and take 2 mol of the anti-shrinkage composite alcohol solution.

[0044] (2) Take 1.7 mol of terephthalic acid, and antimony acetate / antimony trioxide mixed catalyst in a weight ratio of 1:2, with a total amount of 0.07% of terephthalic acid. Add terephthalic acid, anti-shrinkage functional composite alcohol solution, and antimony acetate / antimony trioxide mixed catalyst to the reactor. Turn on the stirring and heating device, set the temperature to 234℃, and control the pressure at 0.21 MPa. When the column top temperature rises to 90℃, the esterification reaction begins. When the column top temperature drops below 40℃ and water is released from the reactor to obtain theoretically esterified water, the esterification is complete. Adjust the reactor temperature to 281℃. After the reactor temperature reaches the set value, start vacuuming. Control the vacuum degree to within 75 Pa. When the stirring power of the reactor increases, the polycondensation reaction begins. The synthesis ends when the target stirring power is reached. Discharge the copolymer, cool it with cooling water, slice it, and dry it at 140℃ for 24 hours to obtain anti-shrinkage functional copolyester chips with an intrinsic viscosity of 0.69 dL / g.

[0045] (3) The polyester chips are melt-spun and corona treatment is performed before the nascent fibers are oiled. The power is set to 2.5KW. TF-719 oil containing 3% vinyl silane and 5% zirconium oxide with a particle size distribution of 20-40nm is used for oiling. Side blowing is used for cooling. The winding speed is 1800m / min, the stretching temperature is 134℃, the stretching ratio is 5, and the heat setting temperature is 160℃ to obtain shrinkage-resistant polyester fibers.

[0046] (4) Take 1m of the obtained anti-shrinkage polyester fiber and ordinary polyester fiber respectively, place them in an environment of 130℃ for 2 hours, record the length after shrinkage, repeat 50 times, take them out and measure the shrinkage rate of ordinary polyester fiber is 3.02% and the shrinkage rate of anti-shrinkage polyester fiber is 0.82%.

[0047] Example 3

[0048] (1) Prepare a solution of ethylene glycol, polycaprolactone diol and pentanediol in a molar ratio of 79:11:12, and take 3 mol of the anti-shrinkage composite alcohol solution.

[0049] (2) Take 2.6 mol of terephthalic acid, and antimony acetate / antimony trioxide mixed catalyst in a weight ratio of 1:2, with a total amount of 0.06% of terephthalic acid. Add terephthalic acid, anti-shrinkage functional composite alcohol solution, and antimony acetate / antimony trioxide mixed catalyst to the reactor. Turn on the stirring and heating device, set the temperature to 236℃, and control the pressure at 0.22 MPa. When the column top temperature rises to 85℃, the esterification reaction begins. When the column top temperature drops below 35℃ and water is released from the reactor to obtain theoretically esterified water, the esterification is complete. Adjust the reactor temperature to 287℃. After the reactor temperature reaches the set value, start vacuuming. Control the vacuum degree to within 70 Pa. When the stirring power of the reactor increases, the polycondensation reaction begins. The synthesis ends when the target stirring power is reached. Discharge the copolymer, cool it with cooling water, slice it, and dry it at 140℃ for 24 hours to obtain anti-shrinkage functional copolyester chips with an intrinsic viscosity of 0.70 dL / g.

[0050] (3) The polyester chips were melt-spun and corona-treated before the nascent fibers were oiled. The power was set to 3KW. TF-719 oil containing 3% vinyl silane and 5% zirconium oxide with a particle size distribution of 20-40nm was used for oiling. Side blowing was used for cooling. The winding speed was 2000m / min, the stretching temperature was 138℃, the stretching ratio was 5, and the heat setting temperature was 161℃ to obtain shrink-resistant polyester.

[0051] (4) Take 1m of the obtained anti-shrinkage polyester fiber and ordinary polyester fiber respectively, place them in an environment of 130℃ for 2 hours, record the length after shrinkage, repeat 50 times, take them out and measure the shrinkage rate of ordinary polyester fiber is 3.40% and the shrinkage rate of anti-shrinkage polyester fiber is 0.95%.

[0052] Comparative Example 1

[0053] (1) Take 1 mol of terephthalic acid, and antimony acetate / antimony trioxide mixed catalyst with a weight ratio of 1:2, the total amount of which is 0.08% of terephthalic acid. Add terephthalic acid, ethylene glycol, and antimony acetate / antimony trioxide mixed catalyst into the reactor, turn on the stirring and heating device, set the temperature to 230℃, control the pressure at 0.20 MPa, and raise the column top temperature to 90℃ to initiate the esterification reaction. When the column top temperature drops below 40℃ and water is released from the reactor to obtain theoretically esterified water, the esterification is complete. Adjust the reactor temperature to 281℃. After the reactor temperature reaches the set value, start vacuuming and control the vacuum degree to within 80 Pa. When the stirring power of the reactor increases, the polycondensation reaction begins. The synthesis ends when the target stirring power is reached. The copolymer is discharged, cooled with cooling water, sliced, and dried at 140℃ for 24 hours to obtain anti-shrinkage functional copolyester chips with an intrinsic viscosity of 0.68 dL / g.

[0054] (2) Polyester chips are melt-spun and corona treatment is performed before oiling the nascent fibers. The power is set to 2KW. TF-719 oil containing 3% vinyl silane and 5% zirconium oxide with a particle size distribution of 20-40nm is used for oiling. Side blowing is used for cooling. The winding speed is 1500m / min, the stretching temperature is 129℃, the stretching ratio is 5, and the heat setting temperature is 158℃ to obtain shrinkage-resistant polyester fibers.

[0055] (3) Take 1m of the obtained polyester fiber and place it in a hot air environment at 130℃ for 2 hours. Record the length after shrinkage. Repeat 50 times and take it out to measure the average fiber shrinkage rate of 1.71%.

[0056] Comparative Example 2

[0057] (1) Prepare a solution of ethylene glycol, polycaprolactone diol and pentanediol in a molar ratio of 78:11:11, and take 2 mol of the anti-shrinkage composite alcohol solution.

[0058] (2) Take 1.7 mol of terephthalic acid, and antimony acetate / antimony trioxide mixed catalyst in a weight ratio of 1:2, with a total amount of 0.07% of terephthalic acid. Add terephthalic acid, anti-shrinkage functional composite alcohol solution, and antimony acetate / antimony trioxide mixed catalyst to the reactor. Turn on the stirring and heating device, set the temperature to 234℃, and control the pressure at 0.21 MPa. When the column top temperature rises to 90℃, the esterification reaction begins. When the column top temperature drops below 40℃ and water is released from the reactor to obtain theoretically esterified water, the esterification is complete. Adjust the reactor temperature to 281℃. After the reactor temperature reaches the set value, start vacuuming. Control the vacuum degree to within 75 Pa. When the stirring power of the reactor increases, the polycondensation reaction begins. The synthesis ends when the target stirring power is reached. Discharge the copolymer, cool it with cooling water, slice it, and dry it at 140℃ for 24 hours to obtain anti-shrinkage functional copolyester chips with an intrinsic viscosity of 0.69 dL / g.

[0059] (3) Zirconia is granulated by a screw extruder to obtain a masterbatch containing 20 wt% zirconia (particle size 20-40 nm). The masterbatch is diluted with the above-mentioned chips in proportion to obtain a masterbatch containing 5 wt% zirconia and dried at 140°C for 24 hours.

[0060] (3) Polyester chips and masterbatch (silica dosage same as in Example 1) were melt-spun. Corona treatment was performed on the nascent fibers before oiling. The power was set to 2KW, and TF-719 oiling agent was used for oiling. Side-blowing cooling was employed. The winding speed was 1500m / min, the drawing temperature was 95℃, the drawing ratio was 2, and the heat setting temperature was 130℃, resulting in shrinkage-resistant polyester fibers. During the spinning process, the component pressure was extremely unstable, with excessively high pressure, triggering alarms and making spinning difficult.

[0061] (4) Take 1m of the obtained polyester fiber and place it in a hot air environment at 130℃ for 2 hours. Record the length after shrinkage. Repeat 50 times. Take it out and measure the average shrinkage rate of the anti-shrinkage polyester fiber, which is 1.33%.

[0062] Comparative Example 3

[0063] (1) Prepare a solution of ethylene glycol, polycaprolactone diol and pentanediol in a molar ratio of 77:11:12, and take 1.2 mol of the anti-shrinkage composite alcohol solution.

[0064] (2) Take 1 mol of terephthalic acid, and antimony acetate / antimony trioxide mixed catalyst at a weight ratio of 1:2, with a total amount of 0.08% of terephthalic acid. Add terephthalic acid, anti-shrinkage functional composite alcohol solution, and antimony acetate / antimony trioxide mixed catalyst to the reactor. Turn on the stirring and heating device, set the temperature to 230℃, and control the pressure at 0.20 MPa. When the column top temperature rises to 90℃, the esterification reaction is in progress. When the column top temperature drops below 40℃, the esterification is complete when water is released from the reactor and theoretically obtained. Adjust the reactor temperature to 281℃. After the reactor temperature reaches the set value, start vacuuming. Control the vacuum degree to within 80 Pa. When the stirring power of the reactor increases, the polycondensation reaction begins. The synthesis ends when the target stirring power is reached. Discharge the copolymer, cool it with cooling water, slice it, and dry it at 140℃ for 24 hours to obtain anti-shrinkage functional copolyester chips with an intrinsic viscosity of 0.68 dL / g.

[0065] (3) The polyester chips are melt-spun using a process containing 3% vinylsilane and 5% particle size distribution.

[0066] Zirconia with a diameter of 20-40 nm was oiled with TF-719 oil, cooled by side blowing, with a winding speed of 1500 m / min, a stretching temperature of 129℃, a stretch ratio of 5, and a heat setting temperature of 158℃ to obtain shrink-resistant polyester fiber.

[0067] (4) Take 1m of the obtained polyester fiber and place it in a hot air environment at 130℃ for 2 hours. Record the length after shrinkage. Repeat 50 times and take it out to measure the average shrinkage rate of 1.12%.

[0068] Comparative Example 4: Compared with Example 1, the difference lies in that the cooling, stretching, and heat setting processes were not specifically designed.

[0069] (1) Prepare a solution of ethylene glycol, polycaprolactone diol and pentanediol in a molar ratio of 77:11:12, and take 1.2 mol of the anti-shrinkage composite alcohol solution.

[0070] (2) Take 1 mol of terephthalic acid, and antimony acetate / antimony trioxide mixed catalyst at a weight ratio of 1:2, with a total amount of 0.08% of terephthalic acid. Add terephthalic acid, anti-shrinkage functional composite alcohol solution, and antimony acetate / antimony trioxide mixed catalyst to the reactor. Turn on the stirring and heating device, set the temperature to 230℃, and control the pressure at 0.20 MPa. When the column top temperature rises to 90℃, the esterification reaction is in progress. When the column top temperature drops below 40℃, the esterification is complete when water is released from the reactor and theoretically obtained. Adjust the reactor temperature to 281℃. After the reactor temperature reaches the set value, start vacuuming. Control the vacuum degree to within 80 Pa. When the stirring power of the reactor increases, the polycondensation reaction begins. The synthesis ends when the target stirring power is reached. Discharge the copolymer, cool it with cooling water, slice it, and dry it at 140℃ for 24 hours to obtain anti-shrinkage functional copolyester chips with an intrinsic viscosity of 0.68 dL / g.

[0071] (3) The polyester chips are melt-spun and corona treatment is performed before the nascent fibers are oiled. The power is set to 2KW. TF-719 oil containing 3% vinyl silane and 5% zirconium oxide with a particle size distribution of 20-40nm is used for oiling. Side blowing is used for cooling. The winding speed is 1500m / min, the stretching temperature is 95℃, the stretching ratio is 2, and the heat setting temperature is 130℃ to obtain shrink-resistant polyester fibers.

[0072] (4) Take 1m of the obtained polyester fiber and place it in a hot air environment at 130℃ for 2 hours. Record the length after shrinkage. Repeat 50 times and take it out to measure the average shrinkage rate of 1.18%.

[0073] Performance comparison:

[0074] Case Average shrinkage rate Example 1 0.51％ ordinary polyester fiber 2.81％ Comparative Example 1 1.71％ Comparative Example 2 1.33％ Comparative Example 3 1.12％ Comparative Example 4 1.18％

[0075] The data comparison in the table above shows that:

[0076] Example 1 shows that the shrinkage rate of polyester fiber is significantly improved compared to ordinary polyester fiber.

[0077] Compared with Example 1, Comparative Example 1 differs in that no modified monomer was added to the polyester. The results show that its shrinkage resistance is not as good as that of Example 1, indicating that the presence of an appropriate amount of modified monomer in the polyester can improve the softness and extensibility of the polyester, and can also affect the crystal structure of the polyester, making it more uniform or less prone to crystallization. By increasing the chain length and molecular weight of the polyester, the heat resistance and solvent resistance of the polyester are further improved, so that the polyester has excellent shrinkage resistance.

[0078] Compared to Example 1, Comparative Example 2 differs in that the inorganic nanomaterials are added during the melting process in the form of masterbatch. The results showed that the component pressure was unstable during spinning, affecting spinnability. Furthermore, adding inorganic nanomaterials in masterbatch form leads to uneven intermolecular forces in certain regions of the fiber, causing disordered molecular arrangement and generating additional internal stress. These additional internal stresses interact with the existing internal stresses, affecting the fiber's shrinkage resistance. In addition, the inorganic nanomaterials within the fiber also affect its shrinkage resistance by influencing internal thermal motion. When the distribution of inorganic nanomaterials within the fiber is not uniform, it disrupts internal thermal motion, thus affecting the fiber's shrinkage resistance.

[0079] Compared with Example 1, Comparative Example 3 differs in that the polyester fiber was not corona treated before oiling. The results showed that corona treatment can improve the surface properties of the fiber, including increasing the surface activity of the fiber, enhancing the adhesion of the fiber, and thus improving the shrinkage resistance of the fiber.

[0080] Compared with Example 1, Comparative Example 4 differs in that it uses a conventional drawing process (drawing temperature 95°C, drawing ratio 2) and a heat setting process (temperature 130°C). The results show that the fiber shrinkage resistance is significantly lower than that of Example 1, indicating that the process of adding inorganic nanoparticles in this invention requires targeted improvements to the post-processing such as drawing.

[0081] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing anti-shrinkage polyester fiber, characterized in that... Includes the following steps: (1) Prepare a mixed solution of ethylene glycol, polycaprolactone diol and pentanediol by mixing them in a molar ratio of (75~85):(10~15):(15~10) to obtain an anti-shrinkage functional composite alcohol solution; (2) Terephthalic acid, anti-shrinkage functional composite alcohol solution and catalyst are mixed and added to the reaction vessel for esterification, polycondensation, discharge and slicing to obtain anti-shrinkage functional copolyester chips; (3) The anti-shrinkage functional copolyester chips are melt-spun, the resulting nascent fibers are corona-treated, and then oiled, cooled, stretched, and heat-set to obtain anti-shrinkage polyester fibers; the solvent for oiling contains inorganic nanomaterials and silane coupling agents; the inorganic nanomaterials include one or more of zirconium oxide, boron nitride, and silicon carbide with a particle size distribution of 10~100nm; the cooling is a cooling air blowing method, which is side blowing, ring blowing, or central radiation blowing; the stretching temperature is 115~150℃, and the stretching ratio is 4~7; the heat-setting temperature is 150~165℃.

2. The preparation method according to claim 1, characterized in that: In step (2), the catalyst is a mixed catalyst composed of antimony acetate and antimony trioxide in a mass ratio of 1:(1.5~2.5), and the total amount is 0.05~0.1wt% of terephthalic acid.

3. The preparation method according to claim 1, characterized in that: In step (2), the esterification temperature is controlled at 220~245℃ and the pressure is controlled at 0.18~0.24Mpa.

4. The preparation method according to claim 1, characterized in that: In step (2), the temperature of the polycondensation is controlled at 270~290℃. After the temperature inside the reactor reaches the set value, the vacuum is started and the vacuum degree is controlled within 80pa.

5. The preparation method according to claim 1, characterized in that: In step (2), the intrinsic viscosity of the anti-shrinkage functional copolyester chips is 0.64~0.70 dL / g.

6. The preparation method according to claim 1, characterized in that: In step (3), the corona power is controlled at 1~5KW.

7. The preparation method according to claim 1, characterized in that: In step (3), the silane coupling agent includes one or more of vinylsilane, aminosilane, and methacryloxysilane.

8. The preparation method according to claim 1, characterized in that: In step (3), the temperatures of the screw heating zone during the melt spinning process are 250~260℃, 255~270℃, 265~280℃, 275~290℃, and 285~298℃, respectively.

9. The preparation method according to claim 1, characterized in that: In step (3), the cross-section of the anti-shrinkage polyester fiber is a circular cross-section or an irregular cross-section.