A pet-based long-acting antistatic master batch and its preparation method and application

Abstract

The application belongs to the technical field of high polymer materials, and particularly relates to a PET-based long-acting antistatic master batch as well as a preparation method and application thereof. The application adopts HBP-IM and HOOC-PEG-COOH as comonomers, and anchors the antistatic active chain segment to the PET main chain through in-situ polycondensation reaction, so as to avoid the resolution and diffusion loss of the antistatic agent in the subsequent use or washing process. The hyperbranched structure provides sufficient free volume for the imidazole salt ion group, and cooperates with the effective passivation of trimethyl phosphate on the catalyst activity and the end capping of the carbodiimide on the carboxyl group, so as to jointly inhibit the ester exchange side reaction that may be intensified in the polycondensation process. The reaction process is precisely controlled through a stepwise reduced-pressure polycondensation program, the functionalized PET copolymer melt obtained from the polymer kettle is directly pumped into a double-screw extruder for blending and granulation in a molten state without cooling and granulation, and the hydrolysis and thermal cracking probability of the PET molecular chain in the secondary heating process is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a PET-based long-lasting antistatic masterbatch, its preparation method, and its application. Background Technology

[0002] Polyethylene terephthalate (PET) is widely used in packaging films, electronic device encapsulation, textile fibers, and engineering plastics due to its excellent mechanical properties, good optical transparency, outstanding gas barrier properties, and environmental friendliness. However, PET molecules are interconnected by covalent bonds, and the molecules themselves cannot ionize or effectively transfer electrons and ions. In addition, the molecular groups have low polarity, resulting in a high surface resistivity of PET materials. This makes them prone to static electricity accumulation during processing and use, leading to serious safety hazards such as dust attraction, electric shock, and even fire and explosion.

[0003] Antistatic modification of PET is the fundamental way to solve the above problems. Existing technologies mainly fall into the following three categories: (1) Surface coating method: Small molecule antistatic agent is coated on the surface of PET products. This method is simple to operate, but the antistatic coating is only physically attached to the substrate and is easily detached due to friction and washing. The antistatic effect cannot last.

[0004] (2) Blending method: Antistatic masterbatch is prepared by melt blending antistatic agents or conductive fillers with PET matrix resin. However, small molecule antistatic agents will inevitably migrate to the surface under thermodynamic drive and gradually precipitate and be lost during use. Although nano-conductive fillers can provide conductive pathways, they are extremely difficult to disperse uniformly in PET high-viscosity melt, and high filler content seriously degrades the transparency and mechanical properties of the product.

[0005] (3) Copolymerization: Antistatic monomers containing polyether segments are copolymerized with PET monomers, and the antistatic segments are chemically bonded to the PET molecular chain. This method improves durability compared to the blending method, but still has fundamental defects: the thermodynamic compatibility between polyether segments and PET segments is limited, and the copolymerized product is prone to micro-phase separation during subsequent processing and use, with the antistatic segments agglomerating and peeling off from the matrix; the introduction of polyether segments during copolymerization significantly aggravates the transesterification side reaction, leading to PET molecular chain breakage, a significant decrease in intrinsic viscosity, and severe deterioration of mechanical properties; existing copolymerization methods all complete the reaction in the polymerization reactor, and after the product is cooled and granulated, it needs to be reheated to a molten state for blending and granulation or finished product molding, which further aggravates PET degradation.

[0006] Therefore, there is an urgent market demand and extremely high industrial value for developing an ultra-long-lasting antistatic PET masterbatch that has non-migrating antistatic components, well-dispersed fillers, no deterioration of matrix properties, and is industrially feasible. Summary of the Invention

[0007] The purpose of this invention is to address existing problems by providing a PET-based long-lasting antistatic masterbatch, its preparation method, and its application.

[0008] This invention is achieved through the following technical solution: A PET-based long-lasting antistatic masterbatch, based on 100 parts by weight of PET prepolymer, comprises the following components in parts by weight: The composition includes 8-15 parts of imidazole salt functionalized hyperbranched polyester (HBP-IM), 6-12 parts of carboxyl-terminated polyethylene glycol (HOOC-PEG-COOH), 4-10 parts of ATO-coated nano-mica powder, 0.5-1.5 parts of titanate coupling agent, 0.3-0.8 parts of carbodiimide hydrolysis resistant agent, 0.1-0.3 parts of trimethyl phosphate, 0.08-0.15 parts of antimony glycolate, and 0.3-0.5 parts of hindered phenolic antioxidant.

[0009] Furthermore, the HBP-IM has a thermal decomposition temperature ≥320℃, a number-average molecular weight Mn=2500~4500, a hydroxyl value of 450~550mg KOH / g, and an imidazole salt grafting rate ≥85%; The HOOC-PEG-COOH has a number-average molecular weight (Mn) of 4000 and a carboxylation rate of ≥97%. The volume resistivity of the ATO-coated nano-mica powder is ≤102Ω·cm, and the sheet diameter is 200~400nm.

[0010] Furthermore, the synthesis of the imidazole salt functionalized hyperbranched polyester (HBP-IM) is as follows: using trimethylolpropane as the core and 2,2-dimethylolpropionic acid as the monomer, a hydroxyl-terminated hyperbranched polyester is synthesized by melt condensation polymerization, and then reacted with 1-methyl-3-glycidylimidazolium chloride at 80°C for 6-8 hours. After purification and drying, HBP-IM is obtained.

[0011] Further, the synthesis of the terminal carboxyl polyethylene glycol (HOOC-PEG-COOH) is as follows: polyethylene glycol (Mn=4000) is reacted with succinic anhydride at 90°C for 8 hours under pyridine catalysis, and after precipitation, washing and drying, terminal carboxyl polyethylene glycol with a carboxylation rate ≥97% is obtained.

[0012] A method for preparing a PET-based long-lasting antistatic masterbatch includes the following steps: (1) PET prepolymer, imidazole salt functionalized hyperbranched polyester, carboxyl-terminated polyethylene glycol, antimony glycol, trimethyl phosphate and carbodiimide hydrolysis resistant agent are put into a polymerization reactor. Under N2 protection, the temperature is raised to 250~255℃. Stirring is maintained at atmospheric pressure to fully mix and melt the components. A step-down pressure reduction program is adopted: the pressure is gradually reduced from atmospheric pressure to ≤50Pa through 1000Pa and 200Pa, and each stage is maintained for 30min. Finally, the polycondensation reaction is carried out at ≤50Pa and 255±2℃ for 2~3h to obtain antistatic functionalized PET copolymer melt. (2) The functionalized PET copolymer melt obtained in step (1) is directly pumped into the side feed port of a twin-screw extruder with an aspect ratio of L / D=(48~52):1 without being cooled and pelletized. ATO-coated nano mica powder is pretreated with titanate coupling agent and fed into the main feed port along with antioxidant at a shear rate of 500~900s. -1 Under the following conditions, the extrusion temperature gradient is as follows: feeding section 230~240℃, shear induction section 265~270℃, homogenization section 260~265℃, and die head 245~250℃; the extrudate is granulated and dried to obtain the finished masterbatch.

[0013] Further, the step-by-step pressure reduction procedure in step (1) is as follows: start the vacuum system, first stage: reduce atmospheric pressure to 1000Pa, maintain 255℃ for 30min; second stage: reduce 1000Pa to 200Pa, maintain 255℃ for 30min; third stage: reduce 200Pa to ≤50Pa, maintain 255℃ for 30min; fourth stage: ≤50Pa, maintain 255±2℃ for 2.5h.

[0014] Furthermore, the shear induction section of the twin-screw extruder in step (2) is equipped with 5 sets of kneading blocks, of which 3 sets are staggered at 60° angles and 2 sets are staggered at 45° angles, and the two are arranged alternately.

[0015] Furthermore, the melt conveying pipeline between the outlet of the polymerization reactor and the feed port of the twin screw extruder is equipped with a heat-insulating jacket to ensure that the temperature difference between the outlet temperature of the polymerization reactor and the feed port on the twin screw extruder side is ≤10℃.

[0016] Further, the method for pretreating the ATO-coated nano mica powder with titanate coupling agent in step (2) is as follows: mix the two in a high-speed mixer at 800~1200 rpm for 8~12 min.

[0017] The application of the PET-based long-lasting antistatic masterbatch in the preparation of antistatic PET products, wherein the masterbatch and PET chips are mixed at a mass ratio of 5:95 to 30:70 and then melt-processed, wherein the melt processing includes at least one of injection molding, extrusion molding, blown film molding or melt spinning.

[0018] The present invention has the following advantages over the prior art: This invention abandons the traditional physical blending or simple copolymerization mode of small molecule antistatic agents. It uses imidazole salt-functionalized hyperbranched polyester (HBP-IM) and carboxyl-terminated polyethylene glycol (HOOC-PEG-COOH) as comonomers. Through in-situ polycondensation, the antistatic active segments are firmly anchored to the PET molecular backbone in the form of chemical bonds. This design fundamentally avoids the desorption and diffusion loss of the antistatic agent during subsequent use or washing. Simultaneously, the unique three-dimensional spherical dense branched structure of the hyperbranched polyester not only provides sufficient free volume for the imidazole salt ionic groups to ensure ion migration efficiency, but its highly branched molecular configuration also reduces the segmental activity of the PEG chain to a certain extent. Combined with the effective passivation of catalyst activity by trimethyl phosphate and the end-capping effect of carbodiimide on the carboxyl groups, this collectively suppresses the transesterification side reactions that may be exacerbated by the introduction of polyether segments during polycondensation.

[0019] This invention precisely controls the reaction process through a step-by-step compression reduction polymerization procedure, and, in conjunction with the synergistic stabilizing effect of carbodiimide hydrolysis-resistant agent and trimethyl phosphate, significantly reduces the risk of thermal oxidative degradation caused by the introduction of polyether segments. Crucially, in the preparation method, the functionalized PET copolymer melt obtained from the polymerization reactor is directly pumped into a twin-screw extruder in a molten state for blending and granulation without cooling and pelletizing, greatly reducing the probability of hydrolysis and thermal decomposition of PET molecular chains during the secondary heating process.

[0020] To address the challenge of agglomeration of ATO-coated nano-mica powder in high-viscosity PET melt, this invention employs two methods: firstly, it uses a titanate coupling agent to pre-treat the filler surface to reduce interfacial tension; secondly, it incorporates five sets of kneading blocks with specific staggered angles in the shear induction section of a twin-screw extruder, matched with a 500-900s... -1 The high shear rate of branched polyester, due to its low intermolecular entanglement and low melt viscosity, reduces the resistance of the melt to the encapsulation of filler particles in the twin-screw shear field. Combined with surface modification by titanate coupling agents, this achieves effective dispersion of ATO mica in the matrix, forcing nanoparticles to achieve uniform nanoscale dispersion (i.e., no agglomeration) within the enrichment region. Simultaneously, a gradient concentration distribution from the surface to the core layer is observed across the overall cross-section of the masterbatch. Furthermore, an insulation jacket between the polymerization outlet and the twin-screw side feed port ensures a temperature difference ≤10℃, guaranteeing the stability and continuity of melt delivery. Detailed Implementation

[0021] The synthesis of imidazole salt-functionalized hyperbranched polyester (HBP-IM) includes the following steps: (A) Synthesis of hydroxyl-terminated hyperbranched polyester (HBP): Trimethylolpropane (0.1 mol) was used as the core and 2,2-dimethylolpropionic acid (1.0 mol) was used as the monomer. The mixture was melted at 140 °C under N2 protection and then gradually heated to 160 °C for 4 h. The temperature was then raised to 180 °C for 2 h. During the reaction, nitrogen was continuously introduced and the water generated in the reaction was continuously removed to obtain hydroxyl-terminated hyperbranched polyester (G2 generation, theoretical molecular weight ≈ 2500). The measured hydroxyl value ranged from 480 to 520 mg KOH / g. (B) Imidazolium salt grafting modification: 50g of the above HBP was dissolved in 200mL of anhydrous N,N-dimethylamide (DMF), 28g of 1-methyl-3-glycidylimidazolium chloride and 0.5g of tetrabutylammonium bromide were added, and the reaction was carried out at 80℃ under N2 protection for 8h. After the reaction was completed, DMF was removed by vacuum distillation. The product was washed repeatedly with anhydrous diethyl ether 3 times and dried under vacuum at 50℃ to constant weight to obtain imidazolium salt functionalized hyperbranched polyester (HBP-IM).

[0022] Synthesis of carboxyl-terminated polyethylene glycol (HOOC-PEG-COOH): 200g of polyethylene glycol (PEG, Mn=4000) was dissolved in 500mL of anhydrous toluene, 60g of succinic anhydride and 5mL of pyridine were added, and the mixture was refluxed at 90℃ under N2 protection for 8h. After the reaction was completed, the reaction solution was slowly poured into excess diethyl ether to precipitate the product. The product was filtered, washed three times with diethyl ether, and dried under vacuum at 40℃ to constant weight to obtain carboxyl-terminated polyethylene glycol with a carboxylation rate ≥97%.

[0023] The preparation of 1-methyl-3-glycidylimidazolium chloride includes the following steps: (a) Dry a 250 mL three-necked flask (equipped with a mechanical stirrer, reflux condenser, constant pressure dropping funnel, and thermometer) at 120 °C for 12 h, assemble it while it is hot, cool it to room temperature under N2 protection, purge with nitrogen 3 times to ensure that the system is anhydrous and oxygen-free, add 1-methylimidazole (0.10 mol, 8.21 g) and anhydrous acetonitrile (50~80 mL) to the three-necked flask, stir to dissolve, and place the flask in an ice-water bath to cool to 3 °C; (b) Place epichlorohydrin in a constant pressure dropping funnel, cool it in an ice-water bath and add it slowly dropwise to the reaction system under N2 protection. After the addition is complete, remove the ice-water bath, slowly raise the temperature to 48°C, and stir the reaction for 21 hours under N2 protection. (c) After the reaction is completed, the reaction solution is cooled to room temperature. Under the conditions of 45°C and vacuum degree ≥ -0.095MPa, acetonitrile and unreacted epichlorohydrin are removed by vacuum distillation to obtain crude product. Anhydrous diethyl ether is added to the crude product, and the mixture is vigorously stirred and washed for 8 min. The mixture is allowed to stand and separate into layers. The lower product phase is collected by liquid separation, and the upper diethyl ether layer is discarded. The washing is repeated 3 times until the diethyl ether layer is colorless. (d) Transfer to a vacuum drying oven and dry to constant weight at 65°C and a vacuum degree ≥ -0.098MPa.

[0024] To further explain the present invention, the following specific embodiments are described.

[0025] Example 1

[0026] A PET-based long-lasting antistatic masterbatch, based on 100 parts by weight of PET prepolymer, comprises the following components in parts by weight: The composition includes 8 parts of imidazole salt functionalized hyperbranched polyester (HBP-IM), 6 parts of carboxyl-terminated polyethylene glycol (HOOC-PEG-COOH), 4 parts of ATO-coated nano-mica powder, 0.5 parts of titanate coupling agent, 0.3 parts of carbodiimide hydrolysis resistant agent, 0.1 parts of trimethyl phosphate, 0.08 parts of antimony glycolate, and 0.3 parts of hindered phenolic antioxidant.

[0027] The preparation method of the PET-based long-lasting antistatic masterbatch includes the following steps: (1) PET prepolymer, imidazole salt functionalized hyperbranched polyester, carboxyl-terminated polyethylene glycol, antimony glycol, trimethyl phosphate and carbodiimide Stabaxol P were added to a polymerization reactor. The temperature was raised to 250°C under N2 protection. Stirring was maintained at atmospheric pressure to ensure that the components were fully mixed and melted. Then the vacuum system was started and a step-by-step pressure reduction procedure was strictly adopted: the first stage was reduced from atmospheric pressure to 1000 Pa and maintained at 255°C for 30 min; the second stage was reduced from 1000 Pa to 200 Pa and maintained at 255°C for 30 min; the third stage was reduced from 200 Pa to ≤50 Pa and maintained at 255°C for 30 min; the fourth stage was ≤50 Pa and maintained at 255±2°C for 2.5 h to obtain antistatic functionalized PET copolymer melt. (2) The obtained functionalized PET copolymer melt is pumped directly from the outlet of the polymerization reactor into the side feed port of the twin-screw extruder through a heat-insulated pipe at 260°C. The melt is fed directly in a liquid molten state without being cooled and granulated. The outlet temperature of the polymerization reactor and the side feed port temperature of the twin-screw extruder are ≤10°C. (3) Pretreated ATO-coated mica powder and antioxidant Irganox 1010 are fed into the twin-screw main feed port according to the ratio, at a shear rate of 500 s. -1 Under the following conditions, melt blending and extrusion were performed with the following temperature gradient: feeding section 230℃, shear induction section 265℃, homogenization section 260℃, and die head 245℃. The extrudate was then granulated and dried to obtain the finished masterbatch. The shear induction section of the twin-screw extruder is equipped with 5 sets of kneading blocks, of which 3 sets are staggered at 60° and 2 sets are staggered at 45°, and the two are arranged alternately.

[0028] Example 2

[0029] A PET-based long-lasting antistatic masterbatch, based on 100 parts by weight of PET prepolymer, comprises the following components in parts by weight: The composition includes 11 parts of imidazole salt functionalized hyperbranched polyester (HBP-IM), 9 parts of carboxyl-terminated polyethylene glycol (HOOC-PEG-COOH), 7 parts of ATO-coated nano-mica powder, 1 part of titanate coupling agent, 0.5 parts of carbodiimide hydrolysis resistant agent, 0.2 parts of trimethyl phosphate, 0.12 parts of antimony glycolate, and 0.4 parts of hindered phenolic antioxidant.

[0030] The preparation method of the PET-based long-lasting antistatic masterbatch includes the following steps: (1) PET prepolymer, imidazole salt functionalized hyperbranched polyester, carboxyl-terminated polyethylene glycol, antimony glycol, trimethyl phosphate and carbodiimide Stabaxol P were added to a polymerization reactor. The temperature was raised to 252°C under N2 protection. The mixture was stirred at atmospheric pressure to ensure that the components were fully mixed and melted. Then the vacuum system was started and a step-by-step pressure reduction procedure was strictly adopted: the first stage was reduced from atmospheric pressure to 1000 Pa and maintained at 255°C for 30 min; the second stage was reduced from 1000 Pa to 200 Pa and maintained at 255°C for 30 min; the third stage was reduced from 200 Pa to ≤50 Pa and maintained at 255°C for 30 min; the fourth stage was ≤50 Pa and maintained at 255±2°C for 2.5 h to obtain antistatic functionalized PET copolymer melt. (2) The obtained functionalized PET copolymer melt is pumped directly from the outlet of the polymerization reactor into the side feed port of the twin-screw extruder through a heat-insulated pipe at 260°C. The melt is fed directly in a liquid molten state without being cooled and granulated. The outlet temperature of the polymerization reactor and the side feed port temperature of the twin-screw extruder are ≤10°C. (3) The pretreated ATO-coated mica powder and antioxidant Irganox 1010 were fed into the twin-screw main feed port according to the ratio, and the mixture was subjected to a shear rate of 700 s. -1 Under the following conditions, melt blending and extrusion were performed with the following temperature gradients: feeding section 235℃, shear induction section 268℃, homogenization section 262℃, and die head 248℃. The extrudate was then granulated and dried to obtain the finished masterbatch. The shear induction section of the twin-screw extruder is equipped with 5 sets of kneading blocks, of which 3 sets are staggered at 60° and 2 sets are staggered at 45°, and the two are arranged alternately.

[0031] Example 3

[0032] A PET-based long-lasting antistatic masterbatch, based on 100 parts by weight of PET prepolymer, comprises the following components in parts by weight: 15 parts of imidazole salt functionalized hyperbranched polyester (HBP-IM), 12 parts of carboxyl-terminated polyethylene glycol (HOOC-PEG-COOH), 10 parts of ATO-coated nano mica powder, 1.5 parts of titanate coupling agent, 0.8 parts of carbodiimide hydrolysis resistant agent, 0.3 parts of trimethyl phosphate, 0.15 parts of antimony glycolate, and 0.5 parts of hindered phenolic antioxidant.

[0033] The preparation method of the PET-based long-lasting antistatic masterbatch includes the following steps: (1) PET prepolymer, imidazole salt functionalized hyperbranched polyester, carboxyl-terminated polyethylene glycol, antimony glycol, trimethyl phosphate and carbodiimide Stabaxol P were added to a polymerization reactor. The temperature was raised to 255°C under N2 protection. The mixture was stirred at atmospheric pressure to ensure that the components were fully mixed and melted. Then the vacuum system was started and a step-by-step pressure reduction procedure was strictly adopted: the first stage was reduced from atmospheric pressure to 1000 Pa and maintained at 255°C for 30 min; the second stage was reduced from 1000 Pa to 200 Pa and maintained at 255°C for 30 min; the third stage was reduced from 200 Pa to ≤50 Pa and maintained at 255°C for 30 min; the fourth stage was ≤50 Pa and maintained at 255±2°C for 2.5 h to obtain antistatic functionalized PET copolymer melt. (2) The obtained functionalized PET copolymer melt is pumped directly from the outlet of the polymerization reactor into the side feed port of the twin-screw extruder through a heat-insulated pipe at 260°C. The melt is fed directly in a liquid molten state without being cooled and granulated. The outlet temperature of the polymerization reactor and the side feed port temperature of the twin-screw extruder are ≤10°C. (3) The pretreated ATO-coated mica powder and antioxidant Irganox 1010 were fed into the twin-screw main feed port according to the ratio, and the mixture was subjected to a shear rate of 900 s. -1 Under the following conditions, melt blending and extrusion were performed with the following extrusion temperature gradient: 240℃ in the feeding section, 270℃ in the shear induction section, 265℃ in the homogenization section, and 250℃ in the die head. The extrudate was then granulated and dried to obtain the finished masterbatch. The shear induction section of the twin-screw extruder is equipped with 5 sets of kneading blocks, of which 3 sets are staggered at 60° and 2 sets are staggered at 45°, and the two are arranged alternately.

[0034] Comparative Example 1 Pure PET chips, without any added antistatic components, are directly injection molded.

[0035] Comparative Example 2 Following the same proportions as in Example 2, but without in-situ polymerization and anchoring reaction, all components were physically mixed directly with PET chips in a high-speed mixer, then melt-blended and granulated using a twin-screw extruder, and finally injection-molded with PET chips at a ratio of 15:85 to prepare samples.

[0036] Comparative Example 3 Antistatic functionalized PET copolymer melt was prepared according to the formulation and in-situ polymerization anchoring steps of Example 2, but using a conventional twin-screw extruder (L / D=36:1, no special kneading block design, shear rate 300s). -1 The same process as in Example 2 is followed by melt blending and granulation.

[0037] Comparative Example 4 The imidazole salt functionalized hyperbranched polyester in Example 2 was replaced with an equimolar linear quaternary ammonium salt (dodecyltrimethylammonium chloride), and the rest of the formulation and process were the same as in Example 2.

[0038] Comparative Example 5 Following method CN104086957A: terephthalic acid (PTA), ethylene glycol (EG), and polyethylene glycol (PEG, Mn=4000) were added to a polymerization reactor at a molar ratio of 100:60:9. Block copolymerization was carried out at 260℃ and ≤60Pa. The product was cooled, granulated, dried, and then reheated and melted to form an antistatic masterbatch. The masterbatch and PET chips were injection molded at a ratio of 15:85.

[0039] 1. Performance Testing (1) Surface resistivity test According to the standard GB / T 31838.2-2019 "Dielectric and resistive properties of solid insulating materials - Part 2: Resistive properties (DC method) - Volume resistivity and volume resistivity".

[0040] (2) Water wash resistance test Test nodes: Samples were taken after 0, 5, 10, 20, 30 and 50 washes respectively, and the surface resistivity was tested according to method 2.1.

[0041] (3) Intrinsic viscosity (IV) test According to the standard GB / T 14190-2017 "Test Methods for Fiber Grade Polyester (PET) Chips".

[0042] (4) Tensile property test According to the standard GB / T 1040.2-2022 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics".

[0043] (5) Impact strength test of cantilever beam Standard: GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams".

[0044] (6) Transmittance and haze test According to the standard GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics".

[0045] 2. Experimental Results The test results are shown in Tables 1 and 2 below.

[0046] Table 1 shows the overall performance data of each embodiment and comparative example.

[0047]

[0048] Table 2. Trend of surface resistivity change during water washing.

[0049] As shown in the table above, the surface resistivity of pure PET is 3.5 × 10⁻⁶. 15 Ω, while the initial surface resistivity of Examples 1-3 is 9.2 × 10 Ω. 8 ~3.8×10 9 All values ​​between Ω meet the antistatic material standard, with Example 2 having a value of 2.8 × 10⁻⁶. 9 Ω, with optimal overall performance. In Example 2, after 50 water washes, the surface resistivity decreased only from 2.8 × 10⁻⁶. 9 Ω increased to 3.4×10 9 The resistivity of Ω indicates that the antistatic component, after being covalently anchored to the PET backbone through in-situ polymerization, undergoes almost no migration or loss during water washing. In contrast, all comparative examples showed varying degrees of performance degradation. Comparative example 2, lacking chemical anchoring of the antistatic agent, experienced a resistivity spike to 10 Ω after only 10 washes. 11 Above Ω, the antistatic function is basically lost after 50 washes. Comparative Example 3 showed a rise to 1.7 × 10⁻⁶ after 50 washes. 10 Ω demonstrates the crucial role of the shear-induced gradient structure in achieving ultra-long-lasting antistatic properties. Comparative Example 4 showed an increase to 3.2 × 10⁻⁶ after 50 water washes. 11 Ω demonstrates that the hyperbranched structure is the structural basis for shear-induced gradient migration; without this structure, conductive fillers cannot effectively accumulate on the surface. Comparative Example 5 showed an increase to 4.3 × 10⁻⁶ after 50 water washes. 11 Although Ω is superior to pure physical blending, its antistatic durability is still significantly inferior to that of Example 2 due to the lack of gradient structure and melt direct feeding protection.

[0050] The intrinsic viscosity of Example 2 was 0.68 dL / g, significantly better than that of Comparative Examples 2 and 5. This indicates that the synergistic effect of trimethyl phosphate passivation of antimony catalyst activity, carbodiimide-terminated carboxyl groups, and melt direct feeding process effectively suppressed transesterification degradation and molecular chain breakage caused by secondary thermal history. The tensile strength and elongation at break of Example 2 were basically the same as those of pure PET, while the impact strength was 16.7% higher than that of pure PET, reflecting the internal toughening effect of hyperbranched HBP-IM. In contrast, Comparative Example 5 showed a significant decrease in impact strength (16.7% lower than that of pure PET) due to a substantial drop in IV, and its tensile strength and elongation at break were also significantly deteriorated.

[0051] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A PET-based long-lasting antistatic masterbatch, characterized in that, Based on 100 parts by weight of PET prepolymer, it consists of the following components in parts by weight: The composition includes 8-15 parts of imidazole salt functionalized hyperbranched polyester, 6-12 parts of carboxyl-terminated polyethylene glycol, 4-10 parts of ATO-coated nano-mica powder, 0.5-1.5 parts of titanate coupling agent, 0.3-0.8 parts of carbodiimide hydrolysis resistant agent, 0.1-0.3 parts of trimethyl phosphate, 0.08-0.15 parts of antimony glycolate, and 0.3-0.5 parts of hindered phenolic antioxidant.

2. The PET-based long-lasting antistatic masterbatch according to claim 1, characterized in that, The HBP-IM has a thermogravimetric temperature ≥320℃, a number-average molecular weight Mn=2500~4500, a hydroxyl value of 450~550mg KOH / g, and an imidazole salt grafting rate ≥85%; The HOOC-PEG-COOH has a number-average molecular weight (Mn) of 4000 and a carboxylation rate of ≥97%. The volume resistivity of the ATO-coated nano-mica powder is ≤102Ω·cm, and the sheet diameter is 200~400nm.

3. The PET-based long-lasting antistatic masterbatch according to claim 1, characterized in that, The synthesis of the imidazole salt functionalized hyperbranched polyester: using trimethylolpropane as the core and 2,2-dimethylolpropionic acid as the monomer, a hydroxyl-terminated hyperbranched polyester was synthesized by melt condensation polymerization, and then reacted with 1-methyl-3-glycidylimidazolium chloride at 80°C for 6-8 hours. After purification and drying, HBP-IM was obtained.

4. The PET-based long-lasting antistatic masterbatch according to claim 1, characterized in that, The synthesis of the terminal carboxyl polyethylene glycol: polyethylene glycol and succinic anhydride were reacted at 90°C for 8 hours under pyridine catalysis, and the mixture was precipitated, washed and dried to obtain terminal carboxyl polyethylene glycol with a carboxylation rate ≥97%.

5. The method for preparing PET-based long-lasting antistatic masterbatch according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) PET prepolymer, imidazole salt functionalized hyperbranched polyester, carboxyl-terminated polyethylene glycol, antimony glycol, trimethyl phosphate and carbodiimide hydrolysis resistant agent are put into a polymerization reactor. Under N2 protection, the temperature is raised to 250~255℃. Stirring is maintained at atmospheric pressure to fully mix and melt the components. A step-down pressure reduction program is adopted: the pressure is gradually reduced from atmospheric pressure to ≤50Pa through 1000Pa and 200Pa, and each stage is maintained for 30min. Finally, the polycondensation reaction is carried out at ≤50Pa and 255±2℃ for 2~3h to obtain antistatic functionalized PET copolymer melt. (2) The functionalized PET copolymer melt obtained in step (1) is directly pumped into the side feed port of a twin-screw extruder with an aspect ratio of L / D=(48~52):1 without being cooled and pelletized. ATO-coated nano mica powder is pretreated with titanate coupling agent and fed into the main feed port along with antioxidant at a shear rate of 500~900s. -1 Under the following conditions, the extrusion temperature gradient is as follows: feeding section 230~240℃, shear induction section 265~270℃, homogenization section 260~265℃, and die head 245~250℃; the extrudate is granulated and dried to obtain the finished masterbatch.

6. The preparation method according to claim 5, characterized in that, The step-by-step pressure reduction procedure described in step (1) is as follows: start the vacuum system, first stage: reduce atmospheric pressure to 1000Pa, maintain 255℃ for 30min; second stage: reduce 1000Pa to 200Pa, maintain 255℃ for 30min; third stage: reduce 200Pa to ≤50Pa, maintain 255℃ for 30min; fourth stage: ≤50Pa, maintain 255±2℃ for 2.5h.

7. The preparation method according to claim 5, characterized in that, The shearing induction section of the twin-screw extruder in step (2) is equipped with 5 sets of kneading blocks, of which 3 sets are staggered at 60° and 2 sets are staggered at 45°, and the two are arranged alternately.

8. The preparation method according to claim 5, characterized in that, The melt conveying pipeline between the outlet of the polymerization reactor and the feed port of the twin screw extruder is equipped with a heat-insulating jacket to ensure that the temperature difference between the outlet temperature of the polymerization reactor and the feed port on the side of the twin screw extruder is ≤10℃.

9. The preparation method according to claim 5, characterized in that, The method for pretreating the ATO-coated nano mica powder with titanate coupling agent in step (2) is as follows: mix the two in a high-speed mixer at 800~1200 rpm for 8~12 min.

10. The application of the PET-based long-lasting antistatic masterbatch according to any one of claims 1 to 4 in the preparation of antistatic PET products, characterized in that, The masterbatch and PET chips are mixed at a mass ratio of 5:95 to 30:70 and then melt-processed into shape. The melt processing includes at least one of injection molding, extrusion molding, blown film molding or melt spinning.

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