Preparation method of modified polyester chip

Abstract

The invention belongs to the technical field of polyester chip preparation, and discloses a preparation method of a modified polyester chip, which comprises the following specific steps: 1, raw material preparation: preparing an industrial-grade polyester chip with good processability and basic physical properties, and then selecting nano silicon dioxide as a functional monomer of the polyester chip; and polyvinylpyrrolidone K30 is used as a dispersing agent. The dispersing agent and the carrier resin are combined, the dispersing agent can reduce the surface tension of the functional monomer and reduce the agglomeration phenomenon among particles, a layer of protective film can be formed on the surface of the functional monomer, mutual attraction and aggregation among the particles are prevented, and the carrier resin and polyester are good in compatibility, so that the anti-aging performance is good. A good dispersion environment can be provided for the functional monomer, the functional monomer and the modified polyester chip are combined, the dispersity of the functional monomer in the modified polyester chip can reach a higher level, the preparation method is relatively simple, and complex polymerization reaction equipment and process are not needed.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester chip preparation, and specifically relates to a method for preparing modified polyester chips. Background Art

[0002] Polyester chips are a basic raw material in the polyester industry chain. They often refer to solid particles of polyethylene terephthalate produced by polymerization reactions. They are white or light yellow transparent particles with regular geometric shapes, which are easy to store and transport. According to their uses and performance, polyester chips can be divided into: fiber-grade polyester chips, bottle-grade polyester chips, film-grade polyester chips, industrial yarn-grade polyester chips, etc., and are widely used in the textile industry, packaging industry, electronic appliances, building materials and other fields.

[0003] The performance of polyester chips made by traditional methods is relatively simple and it is difficult to meet the market demand for functional and high-performance materials. Therefore, they need to be modified. Common modification methods include in-situ polymerization. However, this method still has certain limitations in actual use. In the in-situ polymerization method, the addition of functional monomers will interfere with the polymerization reaction of polyester, resulting in a widening of the molecular weight distribution and the aggregation of functional monomers in the polyester matrix, thereby affecting the spinnability and use characteristics of polyester. In addition, high temperature and high pressure reaction conditions are usually required, and high requirements are placed on equipment, so improvements are needed. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing a modified polyester chip to solve the problems raised in the above background technology.

[0005] In order to achieve the above object, the present invention provides the following technical solution: a method for preparing modified polyester chips, the specific steps are as follows: Step 1: Prepare the ingredients Prepare industrial-grade polyester chips with good processing performance and basic physical properties, then select nano-silica as the functional monomer of the polyester chips; polyvinyl pyrrolidone-K30 as the dispersant; polybutylene terephthalate as the carrier resin; Step 2: Raw material processing Inspect the polyester chips and remove unqualified ones with uneven appearance, impurities and lumps; Put the functional monomer into a vibrating screen and remove the functional monomer with unqualified particle size through screening. Then put the screened functional monomer on the tray of a vacuum drying oven and spread it evenly. After setting the drying parameters of the vacuum drying oven, dry it to remove moisture on the surface of the functional monomer, and then cool it naturally to room temperature. Pour the dispersant into deionized water and stir and mix the water using a high-speed stirrer so that the dispersant can be fully dissolved in the deionized water, thereby preparing a dispersant solution; The treated functional monomer and dispersant solvent are weighed in a ratio of 10:1, and then the functional monomer is slowly added to the dispersant solution. The functional monomer and the dispersant solution are stirred using a high-speed stirrer while the functional monomer is added, so that the functional monomer and the dispersant solution are evenly mixed to prepare a mixed solution. The mixed solution is then placed in an ultrasonic cleaner and ultrasonically treated to further promote the uniform adsorption of the dispersant on the surface of the functional monomer. The pH value of the mixed solution is then adjusted so that the pH value of the mixed solution is maintained in the range of 8-10, thereby enhancing the electrostatic adsorption effect between the dispersant and the functional monomer; The treated mixed solution is transferred to a centrifuge tube, and after setting the centrifugation parameters, the mixed solution is centrifuged to remove excess solvent and unabsorbed dispersant, and then the mixed solution is filtered through a sieve to obtain pure modified functional monomers; Place the modified functional monomer in a vacuum drying oven and spread it evenly. After setting the post-drying parameters, start the vacuum drying oven and dry it to constant weight, then cool it naturally to room temperature. Step 3: Masterbatch preparation According to the mass ratio of 20%:80%, use a high-precision electronic balance to accurately weigh the dried modified functional monomer and carrier resin, add the weighed modified functional monomer and carrier resin into the high-speed mixer, set the mixing parameters, preliminarily mix the modified functional monomer and carrier resin, and then slowly add the preliminarily mixed materials into the preheated internal mixer, then set the rotor speed and preset temperature and start the internal mixer for mixing. As the mixing proceeds, the materials in the internal mixer will gradually melt and the temperature will gradually rise. When the temperature reaches the preset temperature Continue mixing for 10-15 minutes until the mixing is completed, then take out the mixed material and feed it to the feeding port of the twin-screw extruder through a screw conveyor, set the extrusion parameters and start the twin-screw extruder. At this time, the material will be further mixed and plasticized under the rotation and propulsion of the screw and extruded into strips through the die. The extruded strip material is then cooled through a cooling water tank to quickly solidify the material. The cooled material is then sent to a pelletizer for pelletizing. After the pelletized masterbatch is screened by a vibrating screen to remove unqualified particles, a masterbatch product with uniform particle size can be obtained. Step 4: Blending and granulation Weigh the masterbatch and polyester chips in a ratio of 12%:85%, then place the masterbatch and polyester chips in a high-speed mixer for premixing, so that the masterbatch and polyester chips are preliminarily mixed and uniformly mixed to obtain a mixture, and input the premixed mixture into the feeding hopper of the twin-screw extruder. After setting the twin-screw extruder parameters, start the machine. At this time, under the rotation and propulsion of the screw, the mixture will enter the barrel from the feeding hopper. In the barrel, the mixture is sheared, extruded and rubbed by the screw, thereby gradually melting and plasticizing. Then, as the screw rotates, the molten mixture will be transported to the direction of the head and extruded into strips through the die. Finally, the extruded strip mixture is placed in a cooling water tank for cooling and solidification to obtain the modified polyester chip raw material; Step 5: Granulation and packaging The modified polyester chips are placed in a pelletizer, which is then started to cut the modified polyester chips into pellets of a certain length. The cut modified polyester chips are then placed in a vibrating screen for screening. After removing unqualified pellets, the modified polyester chips are placed in an oven for drying to remove surface moisture. After cooling to room temperature, they can be packaged using packaging materials with good moisture-proof and dust-proof properties. After labeling, the finished modified polyester chips are obtained.

[0006] As a preferred technical solution of the present invention, the intrinsic viscosity of the industrial-grade polyester chips described in step 1 needs to be in the range of 0.75-0.79 dL / g, the particle size of the nano-silica described in step 1 is 50-80 nm, and the concentration of the dispersant solution in step 2 is 5-10 wt%.

[0007] As a preferred technical solution of the present invention, the drying parameters of the functional monomer and the modified functional monomer in step 2 are: drying at 80-100° C. for 4-6 hours; and drying at 60-80° C. to constant weight.

[0008] As a preferred technical solution of the present invention, when using the high-speed stirrer described in step 2, the speed needs to be set to 1000-1500 rpm, the stirring time needs to be 10-15 minutes, and the centrifugation parameters described in step 2 are ultrasonic treatment at a frequency of 40 kHz for 20-30 minutes.

[0009] As a preferred technical solution of the present invention, the modified functional monomer described in step 2 needs to be verified for modification effect. The verification method is as follows: using infrared spectroscopy to analyze the changes in surface functional groups of the functional monomer before and after modification to confirm whether the dispersant is successfully adsorbed; using a contact angle meter to measure the contact angle of the modified functional monomer. A decrease in the contact angle indicates that the dispersant reduces the surface energy of the functional monomer and can improve its compatibility with polyester; observing the morphology of the functional monomer before and after modification by scanning electron microscopy. The modified functional monomer should be in the form of evenly dispersed particles without obvious agglomeration.

[0010] As a preferred technical solution of the present invention, the mixing speed of the high-speed mixer in step 3 and step 4 is 500-1000 rpm, and the mixing time is 5-10 minutes.

[0011] As a preferred technical solution of the present invention, the rotor speed of the internal mixer in step 3 needs to be set at 30-50 rpm, and the preset temperature needs to be set within the range of 260-280°C.

[0012] As a preferred technical solution of the present invention, the parameters of the twin-screw extruder in steps 3 and 4 need to be set to: screw speed 200-300 rpm, temperature 250-280°C, and the cooling water tank temperature in steps 3 and 4 is controlled at 20-30°C.

[0013] As a preferred technical solution of the present invention, the pelletizing length of the pelletizer in step three and step five is 3-5 mm.

[0014] The beneficial effects of the present invention are as follows: The present invention combines a dispersant and a carrier resin. The dispersant can reduce the surface tension of the functional monomer and reduce the agglomeration of particles. It can form a protective film on the surface of the functional monomer to prevent the mutual attraction and aggregation of particles. The carrier resin has good compatibility with polyester and can provide a good dispersion environment for the functional monomer. The combination of the two can achieve a higher level of dispersibility of the functional monomer in the modified polyester chips. In addition, the preparation method is relatively simple and does not require complex polymerization reaction equipment and processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing a modified polyester chip, and the specific steps are as follows: Step 1: Prepare the ingredients Prepare industrial-grade polyester chips with good processing performance and basic physical properties, then select nano-silica as the functional monomer of the polyester chips; polyvinyl pyrrolidone-K30 as the dispersant; polybutylene terephthalate as the carrier resin; Step 2: Raw material processing Inspect the polyester chips and remove unqualified ones with uneven appearance, impurities and lumps; Put the functional monomer into a vibrating screen and remove the functional monomer with unqualified particle size through screening. Then put the screened functional monomer on the tray of a vacuum drying oven and spread it evenly. After setting the drying parameters of the vacuum drying oven, dry it to remove moisture on the surface of the functional monomer, and then cool it naturally to room temperature. Pour the dispersant into deionized water and stir and mix the water using a high-speed stirrer so that the dispersant can be fully dissolved in the deionized water, thereby preparing a dispersant solution; The treated functional monomer and dispersant solvent are weighed in a ratio of 10:1, and then the functional monomer is slowly added to the dispersant solution. The functional monomer and the dispersant solution are stirred using a high-speed stirrer while the functional monomer is added, so that the functional monomer and the dispersant solution are evenly mixed to prepare a mixed solution. The mixed solution is then placed in an ultrasonic cleaner and ultrasonically treated to further promote the uniform adsorption of the dispersant on the surface of the functional monomer. The pH value of the mixed solution is then adjusted so that the pH value of the mixed solution is maintained in the range of 8-10, thereby enhancing the electrostatic adsorption effect between the dispersant and the functional monomer; The treated mixed solution is transferred to a centrifuge tube, and after setting the centrifugation parameters, the mixed solution is centrifuged to remove excess solvent and unabsorbed dispersant, and then the mixed solution is filtered through a sieve to obtain pure modified functional monomers; Place the modified functional monomer in a vacuum drying oven and spread it evenly. After setting the post-drying parameters, start the vacuum drying oven and dry it to constant weight, then cool it naturally to room temperature. Step 3: Masterbatch preparation According to the mass ratio of 20%:80%, use a high-precision electronic balance to accurately weigh the dried modified functional monomer and carrier resin, add the weighed modified functional monomer and carrier resin into the high-speed mixer, set the mixing parameters, preliminarily mix the modified functional monomer and carrier resin, and then slowly add the preliminarily mixed materials into the preheated internal mixer, then set the rotor speed and preset temperature and start the internal mixer for mixing. As the mixing proceeds, the materials in the internal mixer will gradually melt and the temperature will gradually rise. When the temperature reaches the preset temperature Continue mixing for 10-15 minutes until the mixing is completed, then take out the mixed material and feed it to the feeding port of the twin-screw extruder through a screw conveyor, set the extrusion parameters and start the twin-screw extruder. At this time, the material will be further mixed and plasticized under the rotation and propulsion of the screw and extruded into strips through the die. The extruded strip material is then cooled through a cooling water tank to quickly solidify the material. The cooled material is then sent to a pelletizer for pelletizing. After the pelletized masterbatch is screened by a vibrating screen to remove unqualified particles, a masterbatch product with uniform particle size can be obtained. Step 4: Blending and granulation Weigh the masterbatch and polyester chips in a ratio of 12%:85%, then place the masterbatch and polyester chips in a high-speed mixer for premixing, so that the masterbatch and polyester chips are preliminarily mixed and uniformly mixed to obtain a mixture, and input the premixed mixture into the feeding hopper of the twin-screw extruder. After setting the twin-screw extruder parameters, start the machine. At this time, under the rotation and propulsion of the screw, the mixture will enter the barrel from the feeding hopper. In the barrel, the mixture is sheared, extruded and rubbed by the screw, thereby gradually melting and plasticizing. Then, as the screw rotates, the molten mixture will be transported to the direction of the head and extruded into strips through the die. Finally, the extruded strip mixture is placed in a cooling water tank for cooling and solidification to obtain the modified polyester chip raw material; Step 5: Granulation and packaging The modified polyester chips are placed in a pelletizer, which is then started to cut the modified polyester chips into pellets of a certain length. The cut modified polyester chips are then placed in a vibrating screen for screening. After removing unqualified pellets, the modified polyester chips are placed in an oven for drying to remove surface moisture. After cooling to room temperature, they can be packaged using packaging materials with good moisture-proof and dust-proof properties. After labeling, the finished modified polyester chips are obtained.

[0018] The combination of dispersant and carrier resin allows the functional monomer to be evenly dispersed in the carrier resin first, and then blended with polyester chips to further achieve uniform distribution of the functional monomer in the polyester chips, prevent agglomeration, and improve its dispersibility. In addition, the preparation method is relatively simple, reducing equipment investment and production costs.

[0019] The intrinsic viscosity of the industrial-grade polyester chips in step 1 needs to be in the range of 0.75-0.79 dL / g, the particle size of the nano-silica in step 1 is 50-80 nm, and the concentration of the dispersant solution in step 2 is 5-10 wt %.

[0020] The intrinsic viscosity of polyester chips can be measured using the Ubbelohde viscometer method; the concentration of the dispersant solution needs to be kept within the range, otherwise too high a concentration may cause the solution viscosity to be too high, affecting the dispersion effect, and too low a concentration may not be able to fully encapsulate the functional monomer.

[0021] The drying parameters of the functional monomer and the modified functional monomer in step 2 are: drying at 80-100° C. for 4-6 hours; and drying at 60-80° C. to constant weight.

[0022] When the moisture content is high, the dispersant may become ineffective or undergo hydrolysis reaction with the polyester, affecting the final performance. When using a vacuum drying oven, the temperature must be controlled within the set range to avoid excessively high temperatures that may cause dispersant decomposition or functional monomer oxidation.

[0023] Among them, when using the high-speed stirrer in step 2, it is necessary to set the speed to 1000-1500 rpm, the stirring time to 10-15 minutes, and the centrifugation parameter in step 2 is ultrasonic treatment at a frequency of 40 kHz for 20-30 minutes.

[0024] The stirring of the high-speed stirrer can ensure the uniformity of the dispersant solution and make the dispersant evenly adsorbed on the monomer surface. The cavitation effect of the ultrasound can destroy the agglomerates of functional monomers and promote the uniform distribution of dispersant molecules on the monomer surface.

[0025] Among them, the modified functional monomer in step 2 needs to be verified for modification effect. The verification method is: through infrared spectroscopy analysis of the changes in the surface functional groups of the functional monomer before and after modification, confirm whether the dispersant is successfully adsorbed; use a contact angle meter to measure the contact angle of the modified functional monomer. The decrease in the contact angle indicates that the dispersant reduces the surface energy of the functional monomer and can improve its compatibility with polyester; observe the morphology of the functional monomer before and after modification through a scanning electron microscope. The modified functional monomer should be in the form of evenly dispersed particles without obvious agglomeration.

[0026] Through surface modification and ultrasonic treatment, the agglomerates of functional monomers are effectively destroyed, and the dispersant forms a uniform protective layer on the monomer surface, significantly improving its dispersibility in polyester chips. It is not easy to cause secondary agglomeration during subsequent processing, thus ensuring the stability of the performance of the modified polyester chips.

[0027] The mixing speed of the high-speed mixer in step 3 and step 4 is 500-1000 rpm, and the mixing time is 5-10 minutes.

[0028] The high-speed mixer generates strong convection and shearing effects on the materials in the mixing chamber through the high-speed rotation of the stirring blades, which initially achieves uniform mixing of the modified functional monomer and the carrier resin, helps to reduce the mixing difficulty in the subsequent process and improve the mixing efficiency.

[0029] The rotor speed of the internal mixer in step 3 needs to be set at 30-50 rpm, and the preset temperature needs to be set within the range of 260-280°C.

[0030] When slowly adding the preliminarily mixed materials into the preheated internal mixer, it is necessary to ensure that the feeding speed is moderate to avoid excessive accumulation of materials in the internal mixer, resulting in uneven mixing. During the mixing process, the rotor exerts strong shear force and extrusion on the materials, so that the modified functional monomers are further dispersed in the carrier resin. At the same time, attention should be paid to controlling the mixing time. If the time is too short, the modified functional monomers will be unevenly dispersed. If the time is too long, it may cause material degradation and affect the performance of the masterbatch.

[0031] The parameters of the twin-screw extruder in step 3 and step 4 need to be set as follows: screw rotation speed 200-300 rpm, temperature 250-280°C, and the temperature of the cooling water tank in step 3 and step 4 is controlled at 20-30°C.

[0032] The temperature of the twin-screw extruder from the feeding section to the die can be set to 250℃, 260℃, 270℃, and 280℃ in sequence to ensure that the temperature in each zone reaches a stable state. At the same time, it needs to be preheated for 30-60 minutes before use to ensure that all parts of the equipment are heated evenly and avoid uneven melting of materials due to local temperature differences.

[0033] Wherein, the pelletizing length of the pelletizer in step 3 and step 5 is 3-5 mm.

[0034] The speed of the pelletizer should match the extrusion speed to ensure the uniformity and continuity of pelletizing.

[0035] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0036] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a modified polyester chip, characterized in that: The specific steps are as follows: Step 1: Prepare the ingredients Prepare industrial-grade polyester chips with good processing performance and basic physical properties, then select nano-silica as the functional monomer of the polyester chips; polyvinyl pyrrolidone-K30 as the dispersant; polybutylene terephthalate as the carrier resin; Step 2: Raw material processing Inspect the polyester chips and remove unqualified ones with uneven appearance, impurities and lumps; Put the functional monomer into a vibrating screen and remove the functional monomer with unqualified particle size through screening. Then put the screened functional monomer on the tray of a vacuum drying oven and spread it evenly. After setting the drying parameters of the vacuum drying oven, dry it to remove moisture on the surface of the functional monomer, and then cool it naturally to room temperature. Pour the dispersant into deionized water and stir and mix the water using a high-speed stirrer so that the dispersant can be fully dissolved in the deionized water, thereby preparing a dispersant solution; The treated functional monomer and dispersant solvent are weighed in a ratio of 10:1, and then the functional monomer is slowly added to the dispersant solution. The functional monomer and the dispersant solution are stirred using a high-speed stirrer while the functional monomer is added, so that the functional monomer and the dispersant solution are evenly mixed to prepare a mixed solution. The mixed solution is then placed in an ultrasonic cleaner and ultrasonically treated to further promote the uniform adsorption of the dispersant on the surface of the functional monomer. The pH value of the mixed solution is then adjusted so that the pH value of the mixed solution is maintained in the range of 8-10, thereby enhancing the electrostatic adsorption effect between the dispersant and the functional monomer; The treated mixed solution is transferred to a centrifuge tube, and after setting the centrifugation parameters, the mixed solution is centrifuged to remove excess solvent and unabsorbed dispersant, and then the mixed solution is filtered through a sieve to obtain pure modified functional monomers; Place the modified functional monomer in a vacuum drying oven and spread it evenly. After setting the post-drying parameters, start the vacuum drying oven and dry it to constant weight, then cool it naturally to room temperature. Step 3: Masterbatch preparation According to the mass ratio of 20%:80%, use a high-precision electronic balance to accurately weigh the dried modified functional monomer and carrier resin, add the weighed modified functional monomer and carrier resin into the high-speed mixer, set the mixing parameters, preliminarily mix the modified functional monomer and carrier resin, and then slowly add the preliminarily mixed materials into the preheated internal mixer, then set the rotor speed and preset temperature and start the internal mixer for mixing. As the mixing proceeds, the materials in the internal mixer will gradually melt and the temperature will gradually rise. When the temperature reaches the preset temperature Continue mixing for 10-15 minutes until the mixing is completed, then take out the mixed material and feed it to the feeding port of the twin-screw extruder through a screw conveyor, set the extrusion parameters and start the twin-screw extruder. At this time, the material will be further mixed and plasticized under the rotation and propulsion of the screw and extruded into strips through the die. The extruded strip material is then cooled through a cooling water tank to quickly solidify the material. The cooled material is then sent to a pelletizer for pelletizing. After the pelletized masterbatch is screened by a vibrating screen to remove unqualified particles, a masterbatch product with uniform particle size can be obtained. Step 4: Blending and granulation Weigh the masterbatch and polyester chips in a ratio of 12%:85%, then place the masterbatch and polyester chips in a high-speed mixer for premixing, so that the masterbatch and polyester chips are preliminarily mixed and uniformly mixed to obtain a mixture, and input the premixed mixture into the feeding hopper of the twin-screw extruder. After setting the twin-screw extruder parameters, start the machine. At this time, under the rotation and propulsion of the screw, the mixture will enter the barrel from the feeding hopper. In the barrel, the mixture is sheared, extruded and rubbed by the screw, thereby gradually melting and plasticizing. Then, as the screw rotates, the molten mixture will be transported to the direction of the head and extruded into strips through the die. Finally, the extruded strip mixture is placed in a cooling water tank for cooling and solidification to obtain the modified polyester chip raw material; Step 5: Granulation and packaging The modified polyester chips are placed in a pelletizer, which is then started to cut the modified polyester chips into pellets of a certain length. The cut modified polyester chips are then placed in a vibrating screen for screening. After removing unqualified pellets, the modified polyester chips are placed in an oven for drying to remove surface moisture. After cooling to room temperature, they can be packaged using packaging materials with good moisture-proof and dust-proof properties. After labeling, the finished modified polyester chips are obtained.

2. The method for preparing a modified polyester chip according to claim 1, wherein: The intrinsic viscosity of the industrial-grade polyester chips in step 1 needs to be in the range of 0.75-0.79 dL / g, the particle size of the nano-silica in step 1 is 50-80 nm, and the concentration of the dispersant solution in step 2 is 5-10 wt %.

3. The method for preparing a modified polyester chip according to claim 1, wherein: The drying parameters of the functional monomer and the modified functional monomer in step 2 are: drying at 80-100° C. for 4-6 hours; and drying at 60-80° C. to constant weight.

4. The method for preparing a modified polyester chip according to claim 1, wherein: When using the high-speed stirrer described in step 2, the speed needs to be set at 1000-1500 rpm, the stirring time needs to be 10-15 minutes, and the centrifugation parameters described in step 2 are ultrasonic treatment at a frequency of 40 kHz for 20-30 minutes.

5. The method for preparing a modified polyester chip according to claim 1, wherein: The modified functional monomer described in step 2 needs to be verified for modification effect. The verification method is as follows: the surface functional group changes of the functional monomer before and after modification are analyzed by infrared spectroscopy to confirm whether the dispersant is successfully adsorbed; the contact angle of the modified functional monomer is measured using a contact angle meter. A decrease in the contact angle indicates that the dispersant reduces the surface energy of the functional monomer and can improve its compatibility with polyester; the morphology of the functional monomer before and after modification is observed by scanning electron microscopy. The modified functional monomer should be in the form of evenly dispersed particles without obvious agglomeration.

6. The method for preparing a modified polyester chip according to claim 1, wherein: The mixing speed of the high-speed mixer in step 3 and step 4 is 500-1000 rpm, and the mixing time is 5-10 minutes.

7. The method for preparing a modified polyester chip according to claim 1, wherein: The rotor speed of the internal mixer described in step 3 needs to be set at 30-50 rpm, and the preset temperature needs to be set in the range of 260-280°C.

8. The method for preparing a modified polyester chip according to claim 1, wherein: The parameters of the twin-screw extruder in steps 3 and 4 need to be set to: screw rotation speed 200-300 rpm, temperature 250-280°C, and the temperature of the cooling water tank in steps 3 and 4 is controlled at 20-30°C.

9. The method for preparing a modified polyester chip according to claim 1, wherein: The pelletizing length of the pelletizer in step 3 and step 5 is 3-5 mm.

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