High-dispersity PPA polymer processing aid and preparation method thereof

Abstract

The invention relates to the technical field of processing aids, in particular to a high-dispersity PPA polymer processing aid and a preparation method thereof, and the high-dispersity PPA polymer processing aid comprises carrier resin, a modified fluorine-containing polymer, a modified amphiphilic block copolymer, tetra [3-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, tris (2, 4-di-tert-butylphenyl) phosphite ester and polyethylene wax. The fluorine-containing polymer is modified to migrate to a metal-melt interface in a high-temperature melting stage, so that a lubricating layer is formed, and the processing flowability is improved; in the cooling stage, the Diels-Alder addition reaction is carried out in the forward direction to generate a bridge ring, and the modified fluorine-containing polymer is fixed on the processed product resin, so that the problem that an auxiliary agent is left on the surface of equipment is solved; 4 [3-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester and tris (2, 4-di-tert-butylphenyl) phosphite protect the furan group and the maleimide group from intact state to the cooling stage.

Description

Technical Field

[0001] This invention relates to the field of processing aids technology, specifically a highly dispersible PPA polymer processing aid and its preparation method. Background Technology

[0002] In the injection molding and extrusion processing of plastic products (such as nylon and polyester), polymer processing aids (PPAs), especially fluoropolymer PPAs, are commonly added to achieve high flowability and high surface quality. However, after fulfilling their interfacial lubrication function, PPAs remain on the surfaces of metal equipment such as screws, barrels, and molds. These PPAs have extremely low surface energy (typically below 20 mN / m), making them not only incompatible with the melt but also reducing the compatibility between pigment particles and the melt. This causes pigment particles to detach from the melt and be captured on the equipment surface, forming residues that act as a continuous source of contamination.

[0003] When subsequent pure melt flows over the equipment surface, these residues are peeled off and incorporated into the main melt, leading to color unevenness issues such as color streaks and spots in subsequent products that cannot be eliminated. Studies have shown that when the residual PPA on the equipment surface exceeds 0.1 mg / cm², it can have a visible negative impact on the color uniformity of light-colored products (such as white and light gray); when the residue exceeds 0.5 mg / cm², obvious color defects will also appear in dark-colored products. Traditional solutions rely on using large amounts of pure resin as cleaning material to clean the equipment multiple times, resulting in a significant waste of raw materials and time. Therefore, developing a new type of PPA that retains its excellent processing performance while preventing its residue on the equipment surface has become an urgent need in the plastics processing industry. Summary of the Invention

[0004] (1) Technical problems to be solved

[0005] The purpose of this invention is to provide a highly dispersible PPA polymer processing aid and its preparation method, thereby solving the problem of aid residue on equipment surfaces.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention provides a highly dispersible PPA polymer processing aid comprising the following components in parts by weight: 55-70 parts carrier resin, 15-25 parts modified fluoropolymer, 10-20 parts modified amphiphilic block copolymer, 0.3-1.0 parts pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3-1.0 parts tris(2,4-di-tert-butylphenyl) phosphite, and 1.0-3.0 parts polyethylene wax;

[0008] The modified fluoropolymer incorporates carboxyl and maleimide groups; the modified amphiphilic block copolymer has furan groups, polyethylene oxide blocks, and poly(styrene-co-maleic anhydride) blocks.

[0009] Furthermore, the carrier resin comprises an ethylene-vinyl acetate copolymer; the vinyl acetate content of the ethylene-vinyl acetate copolymer is 28%.

[0010] Furthermore, the preparation method of the modified fluoropolymer includes the following steps:

[0011] S11. In a three-necked flask, add perfluoroalkyl ethyl iodide and N,N-dimethylformamide solution of acrylic acid, purge with nitrogen to remove oxygen and moisture, heat and stir continuously under nitrogen protection, after the reaction is completed, cool to room temperature, and then slowly add dropwise to ice-cold diethyl ether, filter to collect the precipitate, wash with diethyl ether, and then dry under vacuum to obtain the first compound;

[0012] S12. Dissolve the first compound in N,N-dimethylformamide, add N-(2-aminoethyl)maleimide hydrochloride and 4-dimethylaminopyridine, and slowly add N,N'-dicyclohexylcarbodiimide under ice-water bath and stirring. Remove the ice bath and continue the reaction at room temperature. After the reaction is complete, filter and collect the filtrate. Add the filtrate dropwise to ice-cold diethyl ether to precipitate, filter and collect the solid, wash three times with diethyl ether, and dry under vacuum to obtain the modified fluoropolymer.

[0013] Furthermore, the preparation method of the modified amphiphilic block copolymer includes the following steps:

[0014] S21. In a round-bottom flask, furanol, 2-(dodecyltrithiocarbonate)-2-isobutyric acid, 4-dimethylaminopyridine, and anhydrous dichloromethane were added and dissolved. After cooling in an ice-water bath, an anhydrous dichloromethane solution of N,N'-dicyclohexylcarbodiimide was slowly added dropwise with stirring. After the addition was complete, the ice bath was removed, and the mixture was stirred continuously overnight at room temperature. After the reaction was completed, the filtrate was collected by filtration. The filtrate was washed three times with saturated brine, dried with anhydrous sodium sulfate, filtered, concentrated under reduced pressure by rotary evaporation, and purified by silica gel column chromatography to obtain the second compound.

[0015] S22. Nitrogen gas was introduced into a Schlenk tube, and the second compound, bis(triphenylphosphine)ammonium chloride and anhydrous tetrahydrofuran were added. Then, a tetrahydrofuran solution of ethylene oxide was added, and the reaction was heated and stirred. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to cold n-hexane to precipitate. The precipitate was filtered, washed with cold n-hexane, and dried in a vacuum oven overnight to obtain the third compound.

[0016] S23. In a Schlenk tube, the third compound, styrene, maleic anhydride, azobisisobutyronitrile, and anhydrous 1,4-dioxane were added. After dissolution, the mixture was subjected to three cycles of "freezing-vacuuming-thawing-nitrogen purging" to remove oxygen. The tube was then sealed and reacted in an oil bath. After cooling, the mixture was diluted with tetrahydrofuran and added dropwise to a methanol / water mixture to precipitate. The solid was collected by filtration, washed with a methanol / water mixture, redissolved in tetrahydrofuran, and precipitated again in a methanol / water mixture. The solid was collected by filtration again and dried under vacuum to constant weight to obtain the modified amphiphilic block copolymer.

[0017] Furthermore, the ethylene oxide is first dried with CaH2, then distilled and dissolved in anhydrous tetrahydrofuran.

[0018] Furthermore, the styrene is first washed with sodium hydroxide solution to remove the polymerization inhibitor, then washed with deionized water until neutral, dried with anhydrous magnesium sulfate, and then distilled under reduced pressure to obtain the final product.

[0019] Furthermore, the volume ratio of methanol to water in the methanol / water mixture is 4:1.

[0020] Based on the same inventive concept, in a second aspect, the present invention also provides a method for preparing a highly dispersible PPA polymer processing aid, applicable to the preparation of the aforementioned highly dispersible PPA polymer processing aid, the preparation method comprising the following steps:

[0021] S31. After drying the carrier resin in a forced-air drying oven, put it into a high-speed mixer and add the sieved polyethylene wax, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl) phosphite, modified affinity block copolymer, and modified fluoropolymer in sequence to obtain a mixture.

[0022] S32. The mixture is melt-extruded and granulated using a twin-screw extruder. The resulting granules are dried, sieved using a vibrating screen, and packaged to obtain a highly dispersible PPA polymer processing aid.

[0023] During the high-temperature melting stage, the fluorinated segments of the modified fluoropolymer migrate to the metal-melt interface through their low surface energy, forming a lubricating layer to improve processing fluidity. At the same time, the carboxyl groups in the modified fluoropolymer molecules form hydrogen bonds with the polyethylene oxide blocks of the modified amphiphilic block copolymer, keeping the two modified substances spatially adjacent through hydrogen bonding. The poly(styrene-co-maleic anhydride) blocks of the modified amphiphilic block copolymer have an anchoring function: the styrene units achieve physical compatibility with the processed resin through van der Waals forces, while the maleic anhydride groups react with the terminal hydroxyl or amino groups of the processed resin to achieve preliminary chemical anchoring; the maleimide groups of the modified fluoropolymer undergo a Diels-Alder addition reaction with the furan groups of the modified amphiphilic block copolymer, but at high temperatures, this reaction is reversible, so the two modified substances cannot combine to form a complex. The modified fluoropolymer still plays a role in improving processing performance, while the modified amphiphilic block copolymer is anchored to the processed resin near the modified fluoropolymer; when processing is completed and cooling begins, the reverse Diels-Alder addition reaction becomes difficult, resulting in the formation of a bridged ring. A complex is formed between the two modified substances, fixing the modified fluoropolymer responsible for interfacial lubrication to the processed resin, thus solving the problem of additive residue on the equipment surface.

[0024] The furan and maleimide groups involved in the Diels-Alder cycloaddition reaction between the two modified substances undergo oxidative degradation at high temperatures. Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite provide functional complementarity, protecting the furan and maleimide groups. In high-temperature processing environments, the four phenolic hydroxyl groups in the pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] molecule act as hydrogen donors, capturing initially formed alkyl or peroxy radicals in the melt and generating stable phenoxy radicals via hydrogen atom transfer reactions. This interrupts the free radical chain propagation reaction, protecting the active groups from oxidative degradation. However, this process also generates hydroperoxides, which act as new free radical sources, inducing degradation and consuming pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. The phosphite group in the tris(2,4-di-tert-butylphenyl)phosphite molecule has strong nucleophilicity, which can decompose hydroperoxides into stable alcohols, fundamentally cutting off the regeneration pathway of free radicals and slowing down the consumption rate of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], enabling it to continuously scavenge free radicals throughout the processing and protect the furan group and maleimide group intact until the cooling stage.

[0025] (3) Beneficial effects

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. In the high-temperature melting stage, the modified fluoropolymer migrates to the metal-melt interface to form a lubricating layer to improve processing fluidity; in the processing cooling stage, the Diels-Alder addition proceeds in the forward direction to generate a bridging ring, and a complex is formed between the two modified substances, fixing the modified fluoropolymer onto the resin of the processed product, thereby solving the problem of additive residue on the equipment surface.

[0028] 2. In this invention, the four phenolic hydroxyl groups in the pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] ester molecule can act as hydrogen donors to capture alkyl radicals or peroxy radicals initially formed in the melt and generate stable phenoxy radicals through hydrogen atom transfer reactions, thereby interrupting the free radical chain growth reaction and protecting the furan group and maleimide group from oxidative degradation.

[0029] 3. In this invention, the phosphite group in the tris(2,4-di-tert-butylphenyl)phosphite molecule has strong nucleophilicity, which can decompose hydroperoxide into stable alcohols, fundamentally cutting off the regeneration pathway of free radicals, delaying the consumption rate of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], enabling it to continuously scavenge free radicals throughout the entire processing, and protecting the furan group and maleimide group intact until the cooling stage. Attached Figure Description

[0030] Figure 1 This is a flowchart illustrating the preparation of a highly dispersible PPA polymer processing aid.

[0031] Figure 2 This is a comparison diagram of the first mold of Example 1 and the first mold of Comparative Example 7. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0033] Example 1: This example discloses a highly dispersible PPA polymer processing aid, comprising the following components in parts by weight: 60 parts carrier resin, 18 parts modified fluoropolymer, 14 parts modified amphiphilic block copolymer, 0.5 parts pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.5 parts tris(2,4-di-tert-butylphenyl) phosphite, and 1.5 parts polyethylene wax;

[0034] The modified fluoropolymer incorporates carboxyl and maleimide groups; the modified amphiphilic block copolymer has furan groups, polyethylene oxide blocks, and poly(styrene-co-maleic anhydride) blocks.

[0035] The carrier resin comprises an ethylene-vinyl acetate copolymer; the vinyl acetate content of the ethylene-vinyl acetate copolymer is 28%.

[0036] The preparation method of the modified fluoropolymer includes the following steps:

[0037] S11. In a dry three-necked flask equipped with a magnetic stirrer and a reflux condenser, add 10.0 g of perfluoroalkyl ethyl iodide and 30 mL of N,N-dimethylformamide solution containing 3.0 g of acrylic acid. Purge with nitrogen for 30 min to remove oxygen and moisture. Under nitrogen protection, heat to 70°C and stir continuously for 8 h. After the reaction is complete, cool to room temperature and then slowly add to 200 mL of ice-cold diethyl ether. Filter and collect the resulting white precipitate, wash three times with diethyl ether, and then dry under vacuum at 40°C for 12 h to obtain the first compound.

[0038] S12. Dissolve 5.0 g of the first compound in 20 mL of N,N-dimethylformamide, add 1.2 g of N-(2-aminoethyl)maleimide hydrochloride and 0.1 g of 4-dimethylaminopyridine, and slowly add 1.5 g of N,N'-dicyclohexylcarbodiimide under ice-water bath and stirring. Remove the ice bath and continue the reaction at room temperature for 24 h. After the reaction is complete, filter and collect the filtrate. Add the filtrate dropwise to ice-cold diethyl ether to precipitate, filter and collect the solid, wash three times with diethyl ether, and dry under vacuum to obtain the modified fluoropolymer.

[0039] The preparation method of the modified amphiphilic block copolymer includes the following steps:

[0040] S21. In a dry 250 mL round-bottom flask, add 5.0 g furanol, 20.0 g 2-(dodecyltrithiocarbonate)-2-isobutyric acid, 0.66 g 4-dimethylaminopyridine, and 80 mL anhydrous dichloromethane. After dissolving, cool to 0-5°C in an ice-water bath. While stirring, slowly add 20 mL of anhydrous dichloromethane solution containing 11.2 g N,N'-dicyclohexylcarbodiimide. After the addition is complete, remove the ice bath and stir continuously overnight at room temperature. After the reaction is complete, filter and collect the filtrate. Wash the filtrate three times with saturated brine, dry with anhydrous sodium sulfate, filter, concentrate under reduced pressure by rotary evaporation, and purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10 / 1, v / v) to obtain the second compound.

[0041] S22. Nitrogen gas was introduced into a 100 mL Schlenk tube, and 2.0 g of the second compound, 0.11 g of bis(triphenylphosphine)ammonium chloride and 30 mL of anhydrous tetrahydrofuran were added. Then, 10 mL of a tetrahydrofuran solution containing 10.0 g of ethylene oxide was added using a syringe. The mixture was heated to 60°C and stirred for 24 h. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to 200 mL of cold n-hexane to precipitate the compound. The precipitate was filtered, washed three times with cold n-hexane, and placed in a vacuum drying oven to dry overnight at 40°C to obtain the third compound.

[0042] S23. In a 50 mL Schlenk tube, add 3.0 g of the third compound, 6.24 g of styrene, 5.88 g of maleic anhydride purified by recrystallization from chloroform, 0.02 g of azobisisobutyronitrile, and 30 mL of anhydrous 1,4-dioxane. After dissolution, perform three cycles of "freezing-vacuuming-thawing-nitrogen purging" to remove oxygen. Seal the tube and place it in a 70°C oil bath for 24 h. After cooling, dilute with tetrahydrofuran and add dropwise to 200 mL of methanol / water mixture to precipitate. Filter to collect the solid, wash three times with methanol / water mixture, redissolve the solid in tetrahydrofuran, precipitate again in methanol / water mixture, filter again to collect the solid, and vacuum dry to constant weight to obtain the modified amphiphilic block copolymer.

[0043] The ethylene oxide was first dried with CaH2, then distilled and dissolved in anhydrous tetrahydrofuran.

[0044] The styrene was first washed with 5% sodium hydroxide solution to remove the polymerization inhibitor, then washed with deionized water until neutral, dried with anhydrous magnesium sulfate, and then distilled under reduced pressure to obtain the product.

[0045] The volume ratio of methanol to water in the methanol / water mixture is 4:1.

[0046] The preparation method of the highly dispersible PPA polymer processing aid includes the following steps:

[0047] S31. After drying the carrier resin in a forced-air drying oven at 70°C for 3 hours, put it into a high-speed mixer and add polyethylene wax (passed through a 100-mesh sieve), pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl) phosphite, modified affinity block copolymer, and modified fluoropolymer in sequence. First, run the mixer at 500 rpm for 2 minutes to initially mix the materials, and then adjust the speed to 1500 rpm for 5-8 minutes to obtain the mixture.

[0048] S32. The mixture was melt-extruded and granulated using a twin-screw extruder with a length-to-diameter ratio of 40:1. The process parameters were: zone 1 120°C, zone 2 160°C, zone 3 185°C, zone 4 195°C, zone 5 to die head 190°C, screw speed 320 rpm / min, vacuum degree -0.09 MPa. After extrusion granulation, the resulting granules were dried in a fluidized bed dryer at 50°C for 2 hours, sieved using a vibrating screen, and packaged to obtain a highly dispersible PPA polymer processing aid. The preparation process is as follows: Figure 1 As shown.

[0049] It should be noted that the initial mixing of materials, followed by running at 1500 rpm for 5-8 minutes, generates heat through friction, raising the temperature to 50-60°C. This causes the molten polyethylene wax and carrier resin to become slightly sticky, thus uniformly coating all powder components. This provides a uniform feed for the next step of melt extrusion and initially promotes the contact between the carboxyl groups of the modified fluoropolymer and the polyethylene oxide blocks of the modified affinity block copolymer.

[0050] Example 2: This example discloses a highly dispersible PPA polymer processing aid, comprising the following components in parts by weight: 55 parts carrier resin, 15 parts modified fluoropolymer, 10 parts modified amphiphilic block copolymer, 0.3 parts pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3 parts tris(2,4-di-tert-butylphenyl) phosphite, and 1.0 part polyethylene wax.

[0051] The other components and preparation methods are the same as in Example 1.

[0052] Example 3: This example discloses a highly dispersible PPA polymer processing aid, comprising the following components in parts by weight: 70 parts carrier resin, 25 parts modified fluoropolymer, 20 parts modified amphiphilic block copolymer, 1.0 part pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1.0 part tris(2,4-di-tert-butylphenyl) phosphite, and 3.0 parts polyethylene wax.

[0053] The other components and preparation methods are the same as in Example 1.

[0054] Example 4: This example discloses a highly dispersible PPA polymer processing aid, comprising the following components in parts by weight: 62.5 parts carrier resin, 20 parts modified fluoropolymer, 15 parts modified amphiphilic block copolymer, 0.65 parts pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.65 parts tris(2,4-di-tert-butylphenyl) phosphite, and 2.0 parts polyethylene wax.

[0055] The other components and preparation methods are the same as in Example 1.

[0056] Comparative Example 1: Based on Example 1, except that the modified fluoropolymer in this comparative example does not introduce carboxyl groups.

[0057] The preparation method of the modified fluoropolymer includes the following steps:

[0058] S11. Dissolve 5.0 g of perfluoroalkyl ethyl iodide in 20 mL of N,N-dimethylformamide, add 1.2 g of N-(2-aminoethyl)maleimide hydrochloride and 0.1 g of 4-dimethylaminopyridine, and slowly add 1.5 g of N,N'-dicyclohexylcarbodiimide under ice-water bath and stirring. Remove the ice bath and continue the reaction at room temperature for 24 h. After the reaction is complete, filter and collect the filtrate. Add the filtrate dropwise to ice-cold diethyl ether to precipitate, filter and collect the solid, wash three times with diethyl ether, and dry under vacuum to obtain the modified fluoropolymer.

[0059] The other components and preparation methods are the same as in Example 1.

[0060] Comparative Example 2: Based on Example 1, but unlike Example 1, the modified fluoropolymer in this comparative example does not introduce maleimide groups.

[0061] The preparation method of the modified fluoropolymer includes the following steps:

[0062] S11. In a dry three-necked flask equipped with a magnetic stirrer and a reflux condenser, add 10.0 g of perfluoroalkyl ethyl iodide and 30 mL of N,N-dimethylformamide solution containing 3.0 g of acrylic acid. Purge with nitrogen for 30 min to remove oxygen and moisture. Under nitrogen protection, heat to 70°C and stir continuously for 8 h. After the reaction is complete, cool to room temperature and then slowly add to 200 mL of ice-cold diethyl ether. Filter and collect the resulting white precipitate, wash three times with diethyl ether, and then vacuum dry at 40°C for 12 h to obtain the modified fluoropolymer.

[0063] The other components and preparation methods are the same as in Example 1.

[0064] Comparative Example 3: Based on Example 1, but unlike Example 1, the modified amphiphilic block copolymer in this comparative example does not introduce furan groups.

[0065] The preparation method of the modified amphiphilic block copolymer includes the following steps:

[0066] S21. In a dry 250 mL round-bottom flask, add 20.0 g of 2-(dodecyltrithiocarbonate)-2-isobutyric acid, 0.66 g of 4-dimethylaminopyridine, and 80 mL of anhydrous dichloromethane. After dissolving, cool to 0-5°C in an ice-water bath. While stirring, slowly add 20 mL of anhydrous dichloromethane solution containing 11.2 g of N,N'-dicyclohexylcarbodiimide. After the addition is complete, remove the ice bath and stir continuously overnight at room temperature. After the reaction is complete, filter and collect the filtrate. Wash the filtrate three times with saturated brine, dry with anhydrous sodium sulfate, filter, concentrate under reduced pressure by rotary evaporation, and purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10 / 1, v / v) to obtain the second compound.

[0067] S22. Nitrogen gas was introduced into a 100 mL Schlenk tube, and 2.0 g of the second compound, 0.11 g of bis(triphenylphosphine)ammonium chloride and 30 mL of anhydrous tetrahydrofuran were added. Then, 10 mL of a tetrahydrofuran solution containing 10.0 g of ethylene oxide was added using a syringe. The mixture was heated to 60°C and stirred for 24 h. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to 200 mL of cold n-hexane to precipitate the compound. The precipitate was filtered, washed three times with cold n-hexane, and placed in a vacuum drying oven to dry overnight at 40°C to obtain the third compound.

[0068] S23. In a 50 mL Schlenk tube, add 3.0 g of the third compound, 6.24 g of styrene, 5.88 g of maleic anhydride purified by recrystallization from chloroform, 0.02 g of azobisisobutyronitrile, and 30 mL of anhydrous 1,4-dioxane. After dissolution, perform three cycles of "freezing-vacuuming-thawing-nitrogen purging" to remove oxygen. Seal the tube and place it in a 70°C oil bath for 24 h. After cooling, dilute with tetrahydrofuran and add dropwise to 200 mL of methanol / water mixture to precipitate. Filter to collect the solid, wash three times with methanol / water mixture, redissolve the solid in tetrahydrofuran, precipitate again in methanol / water mixture, filter again to collect the solid, and vacuum dry to constant weight to obtain the modified amphiphilic block copolymer.

[0069] The other components and preparation methods are the same as in Example 1.

[0070] Comparative Example 4: Based on Example 1, but unlike Example 1, the modified amphiphilic block copolymer in this comparative example does not introduce polyethylene oxide blocks.

[0071] The preparation method of the modified amphiphilic block copolymer includes the following steps:

[0072] S21. In a dry 250 mL round-bottom flask, add 5.0 g furanol, 20.0 g 2-(dodecyltrithiocarbonate)-2-isobutyric acid, 0.66 g 4-dimethylaminopyridine, and 80 mL anhydrous dichloromethane. After dissolving, cool to 0-5°C in an ice-water bath. While stirring, slowly add 20 mL of anhydrous dichloromethane solution containing 11.2 g N,N'-dicyclohexylcarbodiimide. After the addition is complete, remove the ice bath and stir continuously overnight at room temperature. After the reaction is complete, filter and collect the filtrate. Wash the filtrate three times with saturated brine, dry with anhydrous sodium sulfate, filter, concentrate under reduced pressure by rotary evaporation, and purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10 / 1, v / v) to obtain the second compound.

[0073] S22. In a 50 mL Schlenk tube, add 3.0 g of the second compound, 6.24 g of styrene, 5.88 g of maleic anhydride purified by recrystallization from chloroform, 0.02 g of azobisisobutyronitrile, and 30 mL of anhydrous 1,4-dioxane. After dissolution, perform three cycles of "freezing-vacuuming-thawing-nitrogen purging" to remove oxygen. Seal the tube and place it in a 70°C oil bath for 24 h. After cooling, dilute with tetrahydrofuran and add dropwise to 200 mL of methanol / water mixture to precipitate. Filter to collect the solid, wash three times with methanol / water mixture, redissolve the solid in tetrahydrofuran, precipitate again in methanol / water mixture, filter again to collect the solid, and vacuum dry to constant weight to obtain the modified amphiphilic block copolymer.

[0074] Comparative Example 5: Based on Example 1, but unlike Example 1, the modified amphiphilic block copolymer in this comparative example does not introduce poly(styrene-co-maleic anhydride) blocks.

[0075] The preparation method of the modified amphiphilic block copolymer includes the following steps:

[0076] S21. In a dry 250 mL round-bottom flask, add 5.0 g furanol, 20.0 g 2-(dodecyltrithiocarbonate)-2-isobutyric acid, 0.66 g 4-dimethylaminopyridine, and 80 mL anhydrous dichloromethane. After dissolving, cool to 0-5°C in an ice-water bath. While stirring, slowly add 20 mL of anhydrous dichloromethane solution containing 11.2 g N,N'-dicyclohexylcarbodiimide. After the addition is complete, remove the ice bath and stir continuously overnight at room temperature. After the reaction is complete, filter and collect the filtrate. Wash the filtrate three times with saturated brine, dry with anhydrous sodium sulfate, filter, concentrate under reduced pressure by rotary evaporation, and purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10 / 1, v / v) to obtain the second compound.

[0077] S22. Nitrogen gas was introduced into a 100 mL Schlenk tube, and 2.0 g of the second compound, 0.11 g of bis(triphenylphosphine)ammonium chloride and 30 mL of anhydrous tetrahydrofuran were added. Then, 10 mL of a tetrahydrofuran solution containing 10.0 g of ethylene oxide was added using a syringe. The mixture was heated to 60°C and stirred for 24 h. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to 200 mL of cold n-hexane to precipitate the product. The precipitate was filtered, washed three times with cold n-hexane, and placed in a vacuum drying oven to dry overnight at 40°C to obtain the modified amphiphilic block copolymer.

[0078] The other components and preparation methods are the same as in Example 1.

[0079] Comparative Example 6: Based on Example 1, except that this comparative example does not include modified fluoropolymers.

[0080] Comparative Example 7: Based on Example 1, except that this comparative example does not include the modified amphiphilic block copolymer.

[0081] Comparative Example 8: Based on Example 1, but unlike Example 1, this comparative example does not include modified fluoropolymers and modified amphiphilic block copolymers.

[0082] Comparative Example 9: Based on Example 1, except that this comparative example does not include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid].

[0083] Comparative Example 10: Based on Example 1, except that this comparative example does not include tris(2,4-di-tert-butylphenyl) phosphite.

[0084] Comparative Example 11: Based on Example 1, except that this comparative example does not include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite.

[0085] Experimental Example 1: The processing aid samples obtained in Examples 1-4 and Comparative Examples 1-11 were used for a direct residual test to assess their impact on the color development of subsequent products. Contamination Stage: 95% nylon 66, 2% black masterbatch, and 3% processing aid sample were mixed and granulated using a twin-screw extruder to obtain contaminated material. The contaminated material was continuously injected into an injection molding machine for 50 cycles to ensure the equipment was thoroughly contaminated. Cleaning Stage: No cleaning was performed; the machine was directly switched to pure nylon 66 resin and continuously injected for 50 cycles (100mm × 100mm × 2mm), collecting flat samples from all cycles. The collected samples were tested. The results are shown in Table 1.

[0086] The test metrics are as follows:

[0087] 1. Color difference measurement: Measure the L, a, b* values ​​of pure nylon 66 standard (uncontaminated) as a reference; measure the L, a, b* values ​​of each sample; calculate the color difference ΔE between each sample and the standard sample ΔE = √(ΔL² + Δa² + Δb*²).

[0088] 2. Surface fluorine content measurement: Take the plate sample from the 5th test, cut it into small pieces of 1cm×1cm, send them into the XPS instrument, and measure them under ultra-high vacuum to calculate the atomic percentage (at%) of fluorine atoms on the surface.

[0089] 3. Adhesion measurement: Take the flat sample from the 5th test, wipe it clean with alcohol, and perform a cross-cut test according to the standard ASTM D3359. Rating the paint film peeling area: 0 (no peeling) to 5 (peeling >65%).

[0090] 4. Accelerated precipitation using a hot oven: Take the plate sample from the 5th cycle, weigh it using an analytical balance (accurate to 0.01 mg), and record the initial weight W0; place the sample in a 120°C oven for 24 hours, remove it, gently rinse the surface with anhydrous ethanol, wash the precipitate into a pre-weighed aluminum dish, evaporate the ethanol, place the aluminum dish in a 120°C oven for 30 minutes, remove it, cool it, and weigh it to obtain the weight of the precipitate W1; calculate the amount of precipitation per unit area: precipitation amount (mg / cm²) = (W1-W0) / sample area.

[0091] 5. Cleaning efficiency measurement (modulus required to clean until color difference ΔE < 2.0): During the cleaning stage, pure nylon 66 is continuously injected, and the color difference ΔE of the sample is measured for each mold; the number of modulus consumed from the start of pure nylon 66 injection until ΔE of two consecutive molds is less than 2.0 is recorded.

[0092] Table 1. Detection of Additive Residues

[0093] Color difference ΔE (Modulus 1) Surface fluorine content (at%) (5th mode) Adhesion rating (Model 5) Heat release (mg / cm²) (Match 5) Required modulus for cleaning until ΔE < 2.0 Example 1 0.78~0.79 0.07~0.08 0 0.004~0.005 1 Example 2 0.82~0.85 0.08~0.09 0 0.005~0.007 1 Example 3 0.81~0.83 0.08~0.09 0 0.005~0.006 1 Example 4 0.79~0.80 0.07~0.08 0 0.004~0.005 1 Comparative Example 1 7.2~7.4 2.1~2.2 5 0.18~0.20 21~23 Comparative Example 2 6.8~7.1 1.9~2.0 5 0.16~0.17 17~19 Comparative Example 3 6.6~7.0 1.8~2.0 5 0.15~0.16 15~18 Comparative Example 4 4.5~4.8 0.9~1.1 3~4 0.08~0.10 8~9 Comparative Example 5 8.5~8.7 2.4~2.6 5 0.21~0.22 27~29 Comparative Example 6 / / / 0.003 / Comparative Example 7 8.5~8.7 2.5~2.6 5 0.22~0.23 28~29 Comparative Example 8 / / / 0.003 / Comparative Example 9 3.2~3.3 0.6~0.7 2 0.05~0.07 4~6 Comparative Example 10 2.7~2.9 0.4~0.5 2 0.04~0.05 3~4 Comparative Example 11 4.8~5.0 1.1~1.2 4 0.10~0.11 10~12

[0094] Based on the results in Table 1, compared with Comparative Example 1, Example 1 shows that the modified fluoropolymer does not introduce carboxyl groups, the two modified substances lose their linkage in the melt, and the additive residue is serious. Compared with Comparative Examples 2 and 3, Example 1 shows that the modified fluoropolymer does not introduce maleimide groups or the modified amphiphilic block copolymer does not introduce furan groups, so the Diels-Alder addition reaction cannot occur to finally lock the modified fluoropolymer, and the additive will remain. Compared with Comparative Example 4, Example 1 shows that the modified amphiphilic block copolymer does not introduce polyethylene oxide blocks, the two modified substances cannot attract each other, and there is additive residue. Compared with Comparative Example 4, Comparative Example 4 has less additive residue, which shows that the amphiphilic block copolymer does not have polyethylene oxide blocks, and a small amount of modified fluoropolymer is anchored. Compared with Comparative Example 5, Example 1 shows that the modified amphiphilic block copolymer lacks poly(styrene-co-maleic anhydride) blocks and cannot be anchored to the resin of the processed product. Therefore, the modified fluoropolymer cannot be anchored through the modified amphiphilic block copolymer. Compared with Comparative Examples 6 and 8, Example 1 lacks fluoropolymers, and no additives remain. Compared with Comparative Example 7, Example 1 lacks modified amphiphilic block copolymers, and the degree of additive residue is serious. Compared with Comparative Examples 9, 10, and 11, Example 1 lacks pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or tris(2,4-di-tert-butylphenyl) phosphite. The Diels-Alder addition reaction ultimately locks in the two modified substances and cannot proceed, resulting in additive residue. Figure 2 This is a comparison diagram of the first mold of Example 1 and the first mold of Comparative Example 7.

[0095] Experimental Example 2: The processing aid samples obtained from Examples 1-4 and Comparative Examples 6-8 were used to verify their ability to improve processing efficiency and quality; Nylon 66 was selected as the resin for the processed products, and a blank group without processing aids was set up; the results are shown in Table 2.

[0096] The test metrics are as follows:

[0097] 1. Processing torque: Nylon 66 was uniformly mixed with 2% of the processing aid sample and then granulated through a twin-screw extruder at a fixed temperature and a fixed screw speed. The torque value of the main extruder was recorded in real time. The lower the torque, the lower the melt viscosity and the smaller the processing resistance.

[0098] 2. Melt Flow Rate (MFR): The MFR value (g / 10min) of the extruded granules is determined according to ASTM D1238 standard at 275°C and 2.16kg load; the higher the MFR value, the better the melt flow.

[0099] 3. Injection pressure: Produce standard tensile specimens using the same injection molding process parameters (injection speed, holding pressure, etc.); record the peak injection pressure: the lower the pressure, the smaller the flow resistance.

[0100] 4. Appearance quality: Observe the surface gloss and whether there are flow lines on the surface.

[0101] 5. Mechanical property retention rate: The tensile strength and notched impact strength of the standard injection-molded tensile specimens are tested and compared with the performance of pure nylon 66. Processing aids should improve processing without affecting the mechanical properties of the matrix.

[0102] Table 2 Improved Processing Efficiency and Quality Inspection

[0103] Processing torque Melt flow rate (MFR) Injection pressure Appearance quality Mechanical property retention rate Blank group 100% 10.0~10.3g / 10min 843~850 bar The surface has a low gloss level and slight flow lines. 100% Example 1 64~65% 28.3~28.5g / 10min 540~546 bar High gloss, no flow lines 98~100% Example 2 65~66% 27.9~28.2g / 10min 545~550 bar High gloss, no flow lines 98~100% Example 3 64~66% 28.1~28.4g / 10min 542~547 bar High gloss, no flow lines 98~100% Example 4 64~65% 28.2~28.5g / 10min 541~546 bar High gloss, no flow lines 98~100% Comparative Example 6 98~100% 10.2~10.4g / 10min 844~849 bar The surface has a low gloss level and slight flow lines. 99~100% Comparative Example 7 64~66% 28.3~28.5g / 10min 540~545 bar High gloss, no flow lines 93~95% Comparative Example 8 99~100% 10.1~10.4g / 10min 846~851 bar The surface has a low gloss level and slight flow lines. 99~100%

[0104] Based on the results in Table 2, compared with the control group, Examples 1-4 and Comparative Example 7 show improved processing efficiency and quality; compared with the control group, Comparative Examples 6 and 8 show no change in processing efficiency and quality.

[0105] Finally, it should be noted that although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly dispersible PPA polymer processing aid, characterized in that, The product comprises the following components in parts by weight: 55-70 parts carrier resin, 15-25 parts modified fluoropolymer, 10-20 parts modified amphiphilic block copolymer, 0.3-1.0 parts pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3-1.0 parts tris(2,4-di-tert-butylphenyl) phosphite, and 1.0-3.0 parts polyethylene wax; The modified fluoropolymer incorporates carboxyl and maleimide groups; the modified amphiphilic block copolymer has furan groups, polyethylene oxide blocks, and poly(styrene-co-maleic anhydride) blocks.

2. The highly dispersible PPA polymer processing aid according to claim 1, characterized in that, The carrier resin comprises an ethylene-vinyl acetate copolymer; the vinyl acetate content of the ethylene-vinyl acetate copolymer is 28%.

3. The highly dispersible PPA polymer processing aid according to claim 1, characterized in that, The preparation method of the modified fluoropolymer includes the following steps: S11. In a three-necked flask, add perfluoroalkyl ethyl iodide and N,N-dimethylformamide solution of acrylic acid, purge with nitrogen to remove oxygen and moisture, heat and stir continuously under nitrogen protection, after the reaction is completed, cool to room temperature, and then slowly add dropwise to ice-cold diethyl ether, filter to collect the precipitate, wash with diethyl ether, and then dry under vacuum to obtain the first compound; S12. Dissolve the first compound in N,N-dimethylformamide, add N-(2-aminoethyl)maleimide hydrochloride and 4-dimethylaminopyridine, and slowly add N,N'-dicyclohexylcarbodiimide under ice-water bath and stirring. Remove the ice bath and continue the reaction at room temperature. After the reaction is complete, filter and collect the filtrate. Add the filtrate dropwise to ice-cold diethyl ether to precipitate, filter and collect the solid, wash three times with diethyl ether, and dry under vacuum to obtain the modified fluoropolymer.

4. The highly dispersible PPA polymer processing aid according to claim 1, characterized in that, The preparation method of the modified amphiphilic block copolymer includes the following steps: S21. In a round-bottom flask, furanol, 2-(dodecyltrithiocarbonate)-2-isobutyric acid, 4-dimethylaminopyridine, and anhydrous dichloromethane were added and dissolved. After cooling in an ice-water bath, an anhydrous dichloromethane solution of N,N'-dicyclohexylcarbodiimide was slowly added dropwise with stirring. After the addition was complete, the ice bath was removed, and the mixture was stirred continuously overnight at room temperature. After the reaction was completed, the filtrate was collected by filtration. The filtrate was washed three times with saturated brine, dried with anhydrous sodium sulfate, filtered, concentrated under reduced pressure by rotary evaporation, and purified by silica gel column chromatography to obtain the second compound. S22. Nitrogen gas was introduced into a Schlenk tube, and the second compound, bis(triphenylphosphine)ammonium chloride and anhydrous tetrahydrofuran were added. Then, a tetrahydrofuran solution of ethylene oxide was added, and the reaction was heated and stirred. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to cold n-hexane to precipitate. The precipitate was filtered, washed with cold n-hexane, and dried in a vacuum oven overnight to obtain the third compound. S23. In a Schlenk tube, the third compound, styrene, maleic anhydride, azobisisobutyronitrile, and anhydrous 1,4-dioxane were added. After dissolution, the mixture was subjected to three cycles of "freezing-vacuuming-thawing-nitrogen purging" to remove oxygen. The tube was then sealed and reacted in an oil bath. After cooling, the mixture was diluted with tetrahydrofuran and added dropwise to a methanol / water mixture to precipitate. The solid was collected by filtration, washed with a methanol / water mixture, redissolved in tetrahydrofuran, and precipitated again in a methanol / water mixture. The solid was collected by filtration again and dried under vacuum to constant weight to obtain the modified amphiphilic block copolymer.

5. The highly dispersible PPA polymer processing aid according to claim 4, characterized in that, The ethylene oxide was first dried with CaH2, then distilled and dissolved in anhydrous tetrahydrofuran.

6. The highly dispersible PPA polymer processing aid according to claim 4, characterized in that, The styrene was first washed with sodium hydroxide solution to remove the polymerization inhibitor, then washed with deionized water until neutral, dried with anhydrous magnesium sulfate, and then distilled under reduced pressure to obtain the product.

7. The highly dispersible PPA polymer processing aid according to claim 4, characterized in that, The volume ratio of methanol to water in the methanol / water mixture is 4:

1.

8. A method for preparing a highly dispersible PPA polymer processing aid, applied to the preparation of the highly dispersible PPA polymer processing aid as described in any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: S31. After drying the carrier resin in a forced-air drying oven, put it into a high-speed mixer and add the sieved polyethylene wax, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl) phosphite, modified affinity block copolymer, and modified fluoropolymer in sequence to obtain a mixture. S32. The mixture is melt-extruded and granulated using a twin-screw extruder. The resulting granules are dried, sieved using a vibrating screen, and packaged to obtain a highly dispersible PPA polymer processing aid.

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