Preparation method of modified MPV foamed particles

Abstract

The invention relates to a preparation method of modified MPV foamed particles. The preparation method comprises the following steps: S1, weighing TPO, SEBS, PP, light calcium carbonate, white oil, zinc stearate and an antioxidant; s2, the raw materials are put into a double-screw extruder to be subjected to melt blending, supercritical carbon dioxide is injected into a melt at the same time, after mixing and plasticizing, the melt is extruded through a die head, then underwater pelletizing is conducted, and a wet MPV foaming particle primary product is obtained; s3, drying and cooling the wet MPV foamed particle primary product to obtain a cooled MPV foamed particle primary product; s4, the cooled MPV foaming particles are conveyed to a corona treatment device to be subjected to corona treatment, and the particles are immediately soaked or sprayed with water-based glue after treatment; and S5, drying the particles coated with the water-based glue, cooling, and packaging to obtain the modified MPV foamed particle finished product. The modified MPV foaming particle has the effect of improving the cohesiveness and long-term cohesiveness of the modified MPV foaming particle.

Description

Technical Field

[0001] This application relates to the field of polymer material processing technology, and in particular to a method for preparing modified MPV foam particles. Background Technology

[0002] MPV foamed granules are made from polyolefin materials such as SEBS (styrene-ethylene-butene-styrene block copolymer), TPO (thermoplastic polyolefin elastomer), and PP (polypropylene) as the main raw materials, through blending, extrusion, and foaming granulation. With its outstanding characteristics such as light weight, excellent flexibility, and good resilience, it has been widely used in many fields such as sports mats, packaging cushioning materials, and shoe materials, and has broad market application prospects.

[0003] However, polyolefin materials are non-polar substances, resulting in low surface energy and weak polarity of MPV foam particles. In actual processing, when combined with polar adhesives (especially water-based adhesives widely promoted under the trend of environmental protection), there are generally problems of insufficient bonding strength and easy delamination during use, which seriously limits their application in high-end bonding and composite scenarios.

[0004] To improve the surface adhesion properties of polyolefins, the industry commonly employs surface modification technologies such as corona treatment, flame treatment, or plasma treatment. Among these, corona treatment has become the mainstream process due to its high efficiency, low cost, and ease of integration into production lines. However, corona treatment suffers from a significant "time-dependent" defect—the polar groups introduced onto the material surface after treatment gradually decay as molecular chain segments migrate, leading to a decrease in surface energy and a significant reduction in adhesive strength over time. This is particularly detrimental to MPV foam granules that require storage and transportation before bonding and molding, often necessitating secondary treatment during actual processing, increasing the number of steps and costs. Summary of the Invention

[0005] To improve the adhesion and long-term bonding of MPV foam particles, this application provides a method for preparing modified MPV foam particles.

[0006] The method for preparing modified MPV foamed granules provided in this application adopts the following technical solution: A method for preparing modified MPV foam particles includes the following steps: S1. Raw material preparation: Weigh the following raw materials by weight: 16-20 parts TPO, 14-18 parts SEBS, 5-8 parts PP, 35-45 parts light calcium carbonate, 16-20 parts white oil, 0.05-0.15 parts zinc stearate, and 0.3-0.7 parts antioxidant. S2. Melt blending and foaming granulation: The raw materials prepared in step S1 are fed into a twin-screw extruder for melt blending. At the same time, supercritical carbon dioxide is injected into the melt as a physical foaming agent through a critical state carbon dioxide injector set on the twin-screw extruder. After thorough mixing and plasticization, the melt is extruded through a die and then underwater pelletized to obtain wet MPV foamed granules. S3. Drying and Cooling: The wet MPV foam granules are dried to remove surface moisture, and then cooled to obtain cooled MPV foam granules. S4. Surface corona treatment and water-based adhesive coating: The cooled MPV foam particles are transported to the corona treatment device for corona treatment. After treatment, the particles are immediately immersed or sprayed with water-based adhesive so that an adhesive film is formed on the surface of the MPV foam particles. S5. Drying after coating and finished product: Dry the particles coated with water-based adhesive to allow the adhesive to solidify into a film. After cooling, package to obtain the modified MPV foam particles finished product.

[0007] By adopting the above technical solution and compounding TPO, SEBS, PP, filler oil, and calcium powder in a specific ratio, the prepared MPV foam particles have excellent flexibility and processability. After corona treatment, they are immediately coated with water-based adhesive, forming a synergistic effect. Corona treatment instantly enhances the surface polarity of the particles and generates active functional groups. Immediate coating can quickly lock the active surface and prevent the migration and decay of polar functional groups. After the adhesive film is cured, a stable polar coating layer is formed, thereby improving the corona treatment time-related defects and significantly improving the bonding stability between the particles and the polar adhesive.

[0008] Preferably, the water-based adhesive comprises methyl methacrylate, butyl acrylate, acrylic acid, hydroxyethyl acrylate, acrylamide, a polyacrylic acid composite system, and fluorinated inorganic fillers, wherein the fluorinated inorganic fillers comprise mica composites and 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0009] By adopting the above technical solution, an acrylic copolymer is prepared from methyl methacrylate, butyl acrylate, acrylic acid, hydroxyethyl acrylate, and acrylamide, which gives the water-based adhesive good film-forming properties and cohesive strength. The polyacrylic acid composite system is introduced, and the abundant carboxyl groups serve as efficient crosslinking reaction sites. The addition of fluorinated inorganic fillers further enhances the strength and function of the water-based adhesive. The fluorinated inorganic fillers enhance the mechanical properties of the coating and impart hydrophobic properties to the surface, thus constructing a strong and durable bonding interface.

[0010] Preferably, the fluorinated inorganic filler is prepared by the following method: Mica powder, cobalt acetate tetrahydrate, ethylene glycol, sodium acetate, and water were mixed and reacted in a reactor under high temperature. After washing and drying, a mica complex was obtained. Acetic acid, tetrabutyl titanate, and anhydrous ethanol were mixed to obtain a tetrabutyl titanate solution. Water, acetic acid, and anhydrous ethanol were mixed, stirred, and then the mica complex was added. After stirring, the pH of the system was adjusted to acidity to obtain a mica dispersion. The tetrabutyl titanate solution was added to the mica dispersion, stirred under water bath conditions, dried, washed, and finally dried again to obtain the mica complex. The mica complex was mixed with anhydrous ethanol, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane and deionized water were added. After stirring and drying, a fluorinated inorganic filler was obtained.

[0011] By adopting the above technical solution, cobalt tetroxide nanoparticles are first loaded onto the surface of mica sheets through hydrothermal synthesis, then titanium dioxide is coated by sol-gel method, and finally fluorinated by perfluorodecyltriethoxysilane. The mica sheet, as a rigid substrate, improves the overall stability and barrier properties of the system. Cobalt tetroxide and titanium dioxide provide high surface energy, enhance the physicochemical bonding with the resin, and further promote the interfacial crosslinking reaction, thereby improving the strength, bonding performance and hydrophobic properties of the water-based adhesive.

[0012] Preferably, the mass ratio of mica powder, cobalt acetate tetrahydrate and tetrabutyl titanate is 1:(14-18):9.8.

[0013] By adopting the above technical solution, the mass ratio of mica powder, cobalt acetate tetrahydrate and tetrabutyl titanate is preferably within the above range, and the cobalt source and titanium source are sufficient, which further promotes the interaction between the active components in the water-based adhesive.

[0014] Preferably, the mass ratio of the mica complex to 1H,1H,2H,2H-perfluorodecyltriethoxysilane is 1:(0.05-0.06).

[0015] By adopting the above technical solution, and preferably within the above range the mass ratio of mica complex to 1H,1H,2H,2H-perfluorodecyltriethoxysilane, an effective monomolecular modification layer can be formed on the surface of the mica complex, thereby improving the overall stability of the prepared fluorinated inorganic filler.

[0016] Preferably, the polyacrylic acid composite system comprises polyacrylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and a binder.

[0017] By adopting the above technical solution, polyacrylic acid, as a high molecular skeleton containing carboxyl groups, is the source of reactivity. 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide activates polyacrylic acid, and the linker, as a crosslinking bridging unit, can form stable crosslinking bonds with the activated polyacrylic acid carboxyl groups to construct a three-dimensional crosslinking network, thereby improving the reactivity of the entire composite system with the surface of corona-activated particles, fluorinated inorganic fillers, and adhesive matrix resin.

[0018] Preferably, the polyacrylic acid composite system is prepared by the following method: Polyacrylic acid was mixed with water, and then 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide was added and stirred. A binder was then added and the mixture was stirred to react. After the reaction, unreacted substances and byproducts were removed by dialysis. After dialysis, the mixture was freeze-dried to obtain the polyacrylic acid composite system.

[0019] By adopting the above technical solution, different types of linker molecules are grafted onto the polyacrylic acid backbone. After dialysis purification, the obtained product removes small molecule byproducts, resulting in good stability of the polyacrylic acid composite system.

[0020] Preferably, the linker comprises L-cysteine.

[0021] By adopting the above technical solution, L-cysteine ​​introduces thiol and amino groups, which enhances the dynamic crosslinking ability, toughness and interfacial bonding of the coating.

[0022] Preferably, the mass ratio of the polyacrylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and the binder is 1:(0.25-0.35):0.4.

[0023] By adopting the above technical solution, and preferably within the above range the mass ratio of acrylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and binder, polyacrylic acid can be efficiently activated, the grafting rate can be improved, and the stability of the prepared water-based adhesive can be further enhanced.

[0024] Preferably, the mass ratio between the polyacrylic acid composite system and the fluorinated inorganic filler is (5-7):1.

[0025] By adopting the above technical solution, the mass ratio between the polyacrylic acid composite system and the fluorinated inorganic filler is preferably within the above range, so that the filler is sufficient to form an effective functional network in the coating, while ensuring that the resin matrix fully encapsulates and bonds it.

[0026] In summary, this application includes at least one of the following beneficial technical effects: The two-step process of "corona treatment" and "instant water-based adhesive coating" is closely combined. The corona treatment instantly increases the polarity of the particle surface, providing a highly active bonding interface for subsequent adhesive coating. Then, water-based adhesive coating is performed immediately to retain the active surface generated by the corona treatment and avoid polarity decay. Finally, the particle surface is coated with a stable polar polymer film (the film formed after the water-based adhesive dries), which improves the adhesion and long-term adhesion of MPV foam particles. Multifunctional adhesives composed of acrylic copolymers, reactive polyacrylic acid composite systems and fluorinated inorganic fillers not only bond strongly to active surfaces, but also form a dense, highly cohesive cross-linked coating on the outside of the particles, achieving a simultaneous and significant improvement in bonding strength, aging resistance and the mechanical properties of the coating itself. The polyacrylic acid composite system forms a three-dimensional network through activation and cross-linking with a binder using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. Optimized formulation improves grafting rate and stability, enhances reactivity with particles, fillers and resins, and improves film toughness. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments: Raw material description: All raw materials in the examples are commercially available; the mica powder has a particle size of 2000 mesh, the organosilicon defoamer is a polyether-modified polysiloxane defoamer, and the antioxidant is obtained by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 3:2. Example 1

[0028] Preparation of fluorinated inorganic fillers: 16.94 g of cobalt acetate tetrahydrate (CAS No.: 6147-53-1) and 20 g of ethylene glycol (CAS No.: 107-21-1) were mixed and stirred. Then, 1.01 g of mica powder, 15 g of sodium acetate, and 80 g of deionized water were added and mixed. The mixture was stirred and dispersed at 150 rpm for 60 min. The mixture was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene and heated to 180 °C for 5 h. The precipitate was washed alternately with deionized water and ethanol and dried at 80 °C for 2 h to obtain a mica complex. 20 g of acetic acid, 12.05 g of tetrabutyl titanate (CAS No.: 5593-70-4), and 40 g of anhydrous ethanol were mixed to obtain a tetrabutyl titanate solution. Deionized water was then added... Acetic acid and anhydrous ethanol were mixed and sonicated for 1 hour. Then, a mica complex was added, and stirring was continued for 25 minutes. The pH was adjusted to 3 with hydrochloric acid to obtain a mica dispersion. Tetrabutyl titanate solution was added to the mica dispersion, and the mixture was stirred in a water bath at 60°C for 2 hours. Then, it was dried at 80°C for 12 hours. Finally, the mixture was washed alternately with deionized water and ethanol, and dried at 80°C for 1 hour to obtain an inorganic complex. 5 g of the inorganic complex was dispersed in 100 g of anhydrous ethanol, and 0.25 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (CAS No.: 101947-16-4) and 1.5 g of deionized water were added. The mixture was stirred continuously for 12 hours and dried at 60°C for 12 hours to obtain a fluorinated inorganic filler.

[0029] Preparation of polyacrylic acid composite system: 12.12 g of polyacrylic acid (CAS No.: 9003-01-4) with a molecular weight of 450 kDa was mixed with 300 g of deionized water to obtain a polyacrylic acid solution. The pH was adjusted to 5 using sodium hydroxide solution, and then 3.03 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (CAS No.: 7084-11-9) was added and the mixture was stirred for 30 min. Then, 4.85 g of the linker L-cysteine ​​(CAS No.: 52-90-4) was added, and the pH was readjusted to 6. The mixture was stirred for 4 h and then transferred to a 12 kDa dialysis bag. Dialysis was performed using 0.2 mM hydrochloric acid solution. After dialysis, the mixture was vacuum dried at -30 °C for 12 h to obtain the polyacrylic acid composite system.

[0030] Preparation of water-based adhesives: Mix 1.4g of fluorinated inorganic filler with 10mL of deionized water and ultrasonically disperse for 30min to obtain an inorganic filler dispersion. Stir 50g of waterborne EAU acrylic adhesive at 300rpm for 10min in an oil bath at 25℃. Then add the inorganic filler dispersion, followed by 7g of polyacrylic acid composite powder. Stir at 500rpm for 30min. Add 2g of propylene glycol methyl ether acetate (CAS No.: 108-65-6) and 0.2g of silicone defoamer sequentially and continue stirring for 10min. Then add 20mL of deionized water and stir for 10min to obtain a waterborne adhesive with a solid content of 20%.

[0031] Preparation of modified MPV foam particles: S1. Raw material preparation: Weigh the following raw materials by weight: 16 parts TPO, 14 parts SEBS, 5 parts PP, 35 parts light calcium carbonate, 16 parts white oil, 0.05 parts zinc stearate, and 0.3 parts antioxidant. S2. Melt blending and foaming granulation: The raw materials prepared in step S1 are fed into a twin-screw extruder and melt blended at a temperature of 160°C. At the same time, supercritical carbon dioxide is injected into the melt as a physical foaming agent through a critical state carbon dioxide injector set on the twin-screw extruder. After thorough mixing and plasticization, the melt is extruded through a die and then underwater pelletized to obtain wet MPV foamed granules. S3. Drying and Cooling: The wet MPV foam granules are dried to remove surface moisture, and then cooled to obtain cooled MPV foam granules. S4. Surface corona treatment and water-based adhesive coating: The cooled MPV foam particles are transported to the corona treatment device for corona treatment. Under air atmosphere, the treatment power is 2kW and the treatment speed is 5m / min, which generates polar groups on the particle surface. After treatment, water-based adhesive is sprayed onto the particles to form an adhesive film on the surface of the MPV foam particles. S5. Drying after coating and finished product: The particles coated with water-based adhesive are dried at 50°C to allow the adhesive to solidify into a film. After cooling, they are packaged to obtain the modified MPV foam particles. Example 2

[0032] Preparation of fluorinated inorganic fillers: 18.75 g of cobalt acetate tetrahydrate was mixed with 20 g of ethylene glycol and stirred. Then, 1.04 g of mica powder, 15 g of sodium acetate, and 80 g of deionized water were added and mixed. The mixture was stirred and dispersed at 150 rpm for 60 min. The mixture was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene and heated to 180 °C for 5 h. The precipitate was washed alternately with deionized water and ethanol and dried at 80 °C for 2 h to obtain the mica complex. 20 g of acetic acid, 10.21 g of tetrabutyl titanate, and 40 g of anhydrous ethanol were mixed to obtain a tetrabutyl titanate solution. Deionized water, acetic acid, and anhydrous ethanol were mixed and sonicated for 1 minute. h, then add the mica complex, continue stirring for 25 min, adjust the pH to 3 with hydrochloric acid to obtain a mica dispersion, add tetrabutyl titanate solution to the mica dispersion, stir for 2 h in a water bath at 60 °C, then dry at 80 °C for 12 h, finally wash with deionized water and ethanol alternately, and dry at 80 °C for 1 h to obtain an inorganic complex, disperse 5 g of the inorganic complex in 100 g of anhydrous ethanol, add 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane and 1.5 g of deionized water, stir continuously for 12 h, and dry at 60 °C for 12 h to obtain fluorinated inorganic filler.

[0033] Preparation of polyacrylic acid composite system: 11.43 g of polyacrylic acid with a molecular weight of 450 kDa was mixed with 300 g of deionized water to obtain a polyacrylic acid solution. The pH was adjusted to 5 using sodium hydroxide solution, and then 4 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide was added and the mixture was stirred for 30 min. Then, 4.57 g of the linker L-cysteine ​​was added, and the pH was readjusted to 6. The mixture was stirred for 4 h and then transferred to a 12 kDa dialysis bag for dialyzing with 0.2 mM hydrochloric acid solution. After dialyzing, the mixture was vacuum dried at -30 °C for 12 h to obtain the polyacrylic acid composite system.

[0034] Preparation of water-based adhesives: Mix 1g of fluorinated inorganic filler with 10mL of deionized water and ultrasonically disperse for 30min to obtain an inorganic filler dispersion. Stir 50g of waterborne EAU acrylic adhesive at 300rpm for 10min in an oil bath at 25℃. Then add the inorganic filler dispersion, followed by 7g of polyacrylic acid composite powder. Stir at 500rpm for 30min. Add 2g of propylene glycol methyl ether acetate and 0.2g of silicone defoamer sequentially and continue stirring for 10min. Finally, add 20mL of deionized water and stir for 10min to obtain a waterborne adhesive with a solid content of 40%.

[0035] Preparation of modified MPV foam particles: S1. Raw material preparation: Weigh the following raw materials by weight: 20 parts TPO, 18 parts SEBS, 8 parts PP, 45 parts light calcium carbonate, 20 parts white oil, 0.1 parts zinc stearate, and 0.7 parts antioxidant. S2. Melt blending and foaming granulation: The raw materials prepared in step S1 are fed into a twin-screw extruder and melt blended at a temperature of 220°C. At the same time, supercritical carbon dioxide is injected into the melt as a physical foaming agent through a critical state carbon dioxide injector set on the twin-screw extruder. After thorough mixing and plasticization, the melt is extruded through a die and then underwater pelletized to obtain wet MPV foamed granules. S3. Drying and Cooling: The wet MPV foam granules are dried to remove surface moisture, and then cooled to obtain cooled MPV foam granules. S4. Surface corona treatment and water-based adhesive coating: The cooled MPV foam particles are transported to the corona treatment device for corona treatment. Under air atmosphere, the treatment power is 10kW and the treatment speed is 1m / min, which generates polar groups on the particle surface. After treatment, the particles are immediately immersed in water-based adhesive, so that an adhesive film is formed on the surface of the MPV foam particles. S5. Drying after coating and finished product: The particles coated with water-based adhesive are dried at 80°C to allow the adhesive to solidify into a film. After cooling, they are packaged to obtain the modified MPV foam particles. Example 3

[0036] Preparation of fluorinated inorganic fillers: 17.91 g of cobalt acetate tetrahydrate was mixed with 20 g of ethylene glycol and stirred. Then, 1.12 g of mica powder, 15 g of sodium acetate, and 80 g of deionized water were added and mixed. The mixture was stirred and dispersed at 150 rpm for 60 min. The mixture was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene and heated to 180 °C for 5 h. The precipitate was washed alternately with deionized water and ethanol and dried at 80 °C for 2 h to obtain the mica complex. 20 g of acetic acid, 10.97 g of tetrabutyl titanate, and 40 g of anhydrous ethanol were mixed to obtain a tetrabutyl titanate solution. Deionized water, acetic acid, and anhydrous ethanol were mixed and sonicated for 1 h. Then, the mica complex was added, and the mixture was stirred for another 25 minutes. The pH was adjusted to 3 using hydrochloric acid to obtain a mica dispersion. Tetrabutyl titanate solution was added to the mica dispersion, and the mixture was stirred in a water bath at 60°C for 2 hours. Then, it was dried at 80°C for 12 hours. Finally, the mixture was washed alternately with deionized water and ethanol, and dried at 80°C for 1 hour to obtain an inorganic complex. 5 g of the inorganic complex was dispersed in 100 g of anhydrous ethanol, and 0.275 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane and 1.5 g of deionized water were added. The mixture was stirred continuously for 12 hours and dried at 60°C for 12 hours to obtain the fluorinated inorganic filler.

[0037] Preparation of polyacrylic acid composite system: 11.76 g of polyacrylic acid with a molecular weight of 450 kDa was mixed with 300 g of deionized water to obtain a polyacrylic acid solution. The pH was adjusted to 5 using sodium hydroxide solution. Then, 3.53 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide was added and the mixture was stirred for 30 min. Then, 4.71 g of the linker L-cysteine ​​was added, and the pH was readjusted to 6. The mixture was stirred for 4 h and then transferred to a 12 kDa dialysis bag. Dialysis was performed using 0.2 mM hydrochloric acid solution. After dialysis, the mixture was vacuum dried at -30 °C for 12 h to obtain the polyacrylic acid composite system.

[0038] Preparation of water-based adhesives: Mix 1.17g of fluorinated inorganic filler with 10mL of deionized water and ultrasonically disperse for 30min to obtain an inorganic filler dispersion. Stir 50g of waterborne EAU acrylic adhesive at 300rpm for 10min in an oil bath at 25℃. Then add the inorganic filler dispersion, followed by 7g of polyacrylic acid composite powder. Stir at 500rpm for 30min. Add 2g of propylene glycol methyl ether acetate and 0.2g of silicone defoamer sequentially and continue stirring for 10min. Finally, add 20mL of deionized water and stir for 10min to obtain a waterborne adhesive with a solid content of 30%.

[0039] Preparation of modified MPV foam particles: S1. Raw material preparation: Weigh the following raw materials by weight: 18 parts TPO, 16 parts SEBS, 6.5 parts PP, 40 parts light calcium carbonate, 18 parts white oil, 0.15 parts zinc stearate, and 0.5 parts antioxidant. S2. Melt blending and foaming granulation: The raw materials prepared in step S1 are fed into a twin-screw extruder and melt blended at a temperature of 190°C. At the same time, supercritical carbon dioxide is injected into the melt as a physical foaming agent through a critical state carbon dioxide injector set on the twin-screw extruder. After thorough mixing and plasticization, the melt is extruded through a die and then underwater pelletized to obtain wet MPV foamed granules. S3. Drying and Cooling: The wet MPV foam granules are dried to remove surface moisture, and then cooled to obtain cooled MPV foam granules. S4. Surface corona treatment and water-based adhesive coating: The cooled MPV foam particles are transported to the corona treatment device for corona treatment. Under air atmosphere, the treatment power is 6kW and the treatment speed is 3m / min, which generates polar groups on the particle surface. Immediately after treatment, the particles are immersed in water-based adhesive, so that an adhesive film is formed on the surface of the MPV foam particles. S5. Drying after coating and finished product: The granules coated with water-based adhesive are dried at 65°C to allow the adhesive to solidify into a film. After cooling, they are packaged to obtain the modified MPV foam granules. Example 4

[0040] Example 4 is based on Example 3. In Example 4, when preparing fluorinated inorganic fillers, 1.38g of mica powder, 15.14g of cobalt acetate tetrahydrate, and 13.48g of tetrabutyl titanate were used. Example 5

[0041] Example 5 is based on Example 3. In Example 5, when preparing fluorinated inorganic filler, the amount of mica powder used is 0.94g, cobalt acetate tetrahydrate is 19.81g, and tetrabutyl titanate is 9.25g. Example 6

[0042] Example 6 is based on Example 3. In Example 6, when preparing fluorinated inorganic fillers, the mica complex in the mica dispersion is ordinary mica powder and is not combined with cobalt acetate tetrahydrate. Example 7

[0043] Example 7 is based on Example 3. In Example 7, when preparing fluorinated inorganic fillers, the mica complex was not compounded with tetrabutyl titanate, but directly combined with 1H,1H,2H,2H-perfluorodecyltriethoxysilane. Example 8

[0044] Example 8 is based on Example 3. In Example 8, 0.15 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was used in the preparation of fluorinated inorganic filler. Example 9

[0045] Example 9 is based on Example 3. In Example 9, 0.4 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was used in the preparation of fluorinated inorganic filler. Example 10

[0046] Example 10 is based on Example 3. In Example 10, when preparing the polyacrylic acid composite system, 12.9g of polyacrylic acid, 1.94g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and 5.16g of binder were added. Example 11

[0047] Example 11 is based on Example 3. In Example 11, when preparing the polyacrylic acid composite system, the amount of polyacrylic acid added is 10.81g, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide is 4.86g, and the binder is 4.33g. Example 12

[0048] Example 12 is based on Example 3, except that the linker L-cysteine ​​is replaced with carboxymethyl cellulose (CAS No.: 9000-11-7). Example 13

[0049] Example 13 is based on Example 3. In Example 13, 2g of fluorinated inorganic filler was added when preparing the water-based adhesive. Example 14

[0050] Example 14 is based on Example 3. In Example 14, 0.82g of fluorinated inorganic filler was added when preparing the water-based adhesive.

[0051] Comparative Example 1 Comparative Example 1 is based on Example 3. In the preparation of the composite inorganic filler system, Comparative Example 1 did not use 1H,1H,2H,2H-perfluorodecyltriethoxysilane for treatment.

[0052] Comparative Example 2 Comparative Example 2 is based on Example 3. In Comparative Example 2, no polyacrylic acid composite system was added when preparing the water-based adhesive.

[0053] Comparative Example 3 Comparative Example 3 is based on Example 3. In the preparation of the water-based adhesive, no fluorinated inorganic filler was added.

[0054] Comparative Example 4 Comparative Example 4 is based on Example 3, but without corona treatment and water-based adhesive coating.

[0055] Comparative Example 5 Comparative Example 5 is based on Example 3, but without water-based adhesive coating. The particles were stored at room temperature for 7 days after corona treatment.

[0056] Performance testing The following performance tests were performed on the samples of Examples 1-14 and Comparative Examples 1-5: (1) Peel strength Using GB / T 532-2008 as the testing reference, a sample was prepared by bonding a piece of polyester fiber base fabric with water-based EAU acrylic adhesive. The peel strength of the sample was then tested, and the bonding interface state was observed. Each sample was tested 3 times, and the average value was taken. The test results were recorded in Table 1.

[0057] (2) Long-term peel strength Based on GB / T 532-2008 and GB / T 3512-2014, the peel test specimens of (1) were re-prepared, placed in a hot air aging chamber, and aged at 100℃ for 72 hours. Then the peel strength was re-tested. Each specimen was tested 3 times, and the average value was taken. The test results were filled in Table 1.

[0058] (3) Corrosion resistance Using GB / T 11547-2008 as the testing reference, the corrosion resistance of the samples was tested. Each sample was tested 3 times, and the average value was taken. The test results were recorded in Table 1.

[0059] Table 1 Performance test results of Examples 1-14 and Comparative Examples 1-3

[0060] The peel strength of Examples 1-3 is 17 N / cm or higher, the bonding interface is firm, the peel strength after aging is 26 N / cm or higher, and the strength retention rate after NaCl corrosion is 85% or higher, indicating that this application has good adhesion, long-term adhesion and corrosion resistance.

[0061] In Examples 4 and 5, mica powder, cobalt acetate tetrahydrate, and tetrabutyl titanate are not within the scope of this application. When cobalt acetate tetrahydrate is insufficient, the cobalt tetroxide nanoparticles generated by the hydrothermal reaction are too few and cannot synergistically enhance with titanium dioxide, thus failing to form a strong interfacial interlocking state. When cobalt acetate tetrahydrate is excessive, cobalt tetroxide agglomerates on the mica surface, making it difficult to disperse evenly, reducing stability, and the filler has strong polarity, resulting in pinholes during adhesive coating.

[0062] In Example 6, the fluorinated inorganic filler lacked cobalt tetroxide, the mica surface was smooth, and titanium dioxide could only form a thin coating, resulting in a decreased bonding effect. In Example 7, the absence of titanium dioxide prevented the filling of the gaps in cobalt tetroxide, the uneven modification of perfluorosilane made it difficult to form an effective barrier layer, and the corrosion resistance also decreased.

[0063] In Examples 8 and 9, the mass ratio between the inorganic composite and 1H,1H,2H,2H-perfluorodecyltriethoxysilane was not within the range specified in this application. When 1H,1H,2H,2H-perfluorodecyltriethoxysilane was insufficient, it was difficult to form a complete monomolecular hydrophobic layer on the surface of the inorganic filler, and the condensation reaction with the hydroxyl groups on the surface of titanium dioxide and mica was insufficient, resulting in a decrease in the interfacial compatibility between the filler and the adhesive. When 1H,1H,2H,2H-perfluorodecyltriethoxysilane was in excess, the fluorocarbon chains excessively aggregated on the surface of the filler, hindering the bonding between the filler and the polyacrylic acid composite system, and reducing the interfacial compatibility between the filler and the water-based adhesive.

[0064] In Examples 10 and 11, the mass ratios of polyacrylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and the binder were not within the ranges specified in this application. When 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide was insufficient, the carboxyl groups of polyacrylic acid were not sufficiently activated, the crosslinking reaction with L-cysteine ​​was incomplete, and the stability decreased. When 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide was excessive, some carboxyl groups of polyacrylic acid were overactivated, the crosslinking network of the polyacrylic acid composite system was uneven, and the stability decreased.

[0065] In Example 12, the linker L-cysteine ​​was replaced with carboxymethyl cellulose. Carboxymethyl cellulose can only form static hydrogen bonds through hydroxyl and carboxyl groups for cross-linking, and its dynamic cross-linking ability is weak, resulting in decreased stability and corrosion resistance.

[0066] In Examples 13 and 14, the mass ratio between the polyacrylic acid composite system and the fluorinated inorganic filler is not within the range specified in this application. When the fluorinated inorganic filler is excessive, it is difficult to be completely encapsulated by the polyacrylic acid composite system. The filler particles agglomerate and are exposed on the surface of the film, which destroys the continuity of the film. When the fluorinated inorganic filler is insufficient, its reinforcing, hydrophobic and other functionalities are not fully realized, and the stability decreases.

[0067] Comparative Example 1 did not use 1H,1H,2H,2H-perfluorodecyltriethoxysilane for treatment. The surface of the inorganic filler system has the characteristics of hydrophilic metal oxide, which makes it difficult to effectively repel corrosive media and reduces the interfacial bonding.

[0068] The water-based adhesive in Comparative Example 2 did not contain a polyacrylic acid composite system, making it difficult to form sufficiently dense and strong chemical bonds with the transient active groups generated by corona discharge, resulting in decreased long-term adhesion and stability.

[0069] In Comparative Example 3, no fluorinated inorganic filler was added to the water-based adhesive, resulting in the absence of the mica lamellar reinforcement effect and the nano-reinforcement effect of titanium dioxide and cobalt tetroxide. The hydrophobic properties also decreased, and the bonding stability of the system decreased.

[0070] Comparative Example 4 had neither corona treatment nor water-based adhesive coating. The surface of the MPV particles was a non-polar polyolefin structure. Without corona treatment, polar active groups could not be generated, and without adhesive coating, a stable polar coating layer was lacking.

[0071] Comparative Example 5 was only subjected to corona treatment without being coated with water-based adhesive and stored at room temperature for 7 days. Although corona treatment can instantly increase the surface polarity of particles and generate active functional groups such as hydroxyl and carboxyl groups, the fluidity of polyolefin molecular chains will cause the polar groups to migrate and decay rapidly.

[0072] This specific embodiment is merely an explanation of this application and is not intended to limit it. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification but must be determined according to the scope of the claims.

Claims

1. A method for preparing modified MPV foam particles, characterized in that: Includes the following steps: S1. Raw material preparation: Weigh the following raw materials by weight: 16-20 parts TPO, 14-18 parts SEBS, 5-8 parts PP, 35-45 parts light calcium carbonate, 16-20 parts white oil, 0.05-0.15 parts zinc stearate, and 0.3-0.7 parts antioxidant. S2. Melt blending and foaming granulation: The raw materials prepared in step S1 are fed into a twin-screw extruder for melt blending. At the same time, supercritical carbon dioxide is injected into the melt as a physical foaming agent through a critical state carbon dioxide injector set on the twin-screw extruder. After thorough mixing and plasticization, the melt is extruded through a die and then underwater pelletized to obtain wet MPV foamed granules. S3. Drying and Cooling: The wet MPV foam granules are dried to remove surface moisture, and then cooled to obtain cooled MPV foam granules. S4. Surface corona treatment and water-based adhesive coating: The cooled MPV foam particles are transported to the corona treatment device for corona treatment. After treatment, the particles are immediately immersed or sprayed with water-based adhesive so that an adhesive film is formed on the surface of the MPV foam particles. S5. Drying after coating and finished product: Dry the particles coated with water-based adhesive to allow the adhesive to solidify into a film. After cooling, package to obtain the modified MPV foam particles finished product.

2. The method for preparing modified MPV foam particles according to claim 1, characterized in that: The water-based adhesive comprises a composite system of methyl methacrylate, butyl acrylate, acrylic acid, hydroxyethyl acrylate, acrylamide, and polyacrylic acid, and a fluorinated inorganic filler, wherein the fluorinated inorganic filler comprises a mica composite and 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

3. The method for preparing modified MPV foam particles according to claim 2, characterized in that: The fluorinated inorganic filler was prepared by the following method: Mica powder, cobalt acetate tetrahydrate, ethylene glycol, sodium acetate, and water were mixed and reacted in a reactor under high temperature. After washing and drying, a mica complex was obtained. Acetic acid, tetrabutyl titanate, and anhydrous ethanol were mixed to obtain a tetrabutyl titanate solution. Water, acetic acid, and anhydrous ethanol were mixed, stirred, and then the mica complex was added. After stirring, the pH of the system was adjusted to acidity to obtain a mica dispersion. The tetrabutyl titanate solution was added to the mica dispersion, stirred under water bath conditions, dried, washed, and finally dried again to obtain the mica complex. The mica complex was mixed with anhydrous ethanol, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane and deionized water were added. After stirring and drying, a fluorinated inorganic filler was obtained.

4. The method for preparing modified MPV foam particles according to claim 3, characterized in that: The mass ratio of mica powder, cobalt acetate tetrahydrate and tetrabutyl titanate is 1:(14-18):9.

8.

5. The method for preparing modified MPV foam particles according to claim 3, characterized in that: The mass ratio of the mica complex to 1H,1H,2H,2H-perfluorodecyltriethoxysilane is 1:(0.05-0.06).

6. The method for preparing modified MPV foam particles according to claim 2, characterized in that: The polyacrylic acid composite system includes polyacrylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and L-cysteine.

7. The method for preparing modified MPV foam particles according to claim 6, characterized in that: The polyacrylic acid composite system was prepared using the following method: Polyacrylic acid was mixed with water, and then 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide was added and stirred. A binder was then added and the mixture was stirred to react. After the reaction, unreacted substances and byproducts were removed by dialysis. After dialysis, the mixture was freeze-dried to obtain the polyacrylic acid composite system.

8. The method for preparing modified MPV foam particles according to claim 7, characterized in that: The linker includes L-cysteine.

9. The method for preparing modified MPV foam particles according to claim 7, characterized in that: The mass ratio of acrylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and binder is 1:(0.25-0.35):0.

4.

10. The method for preparing modified MPV foam particles according to claim 2, characterized in that: The mass ratio between the polyacrylic acid composite system and the fluorinated inorganic filler is (5-7):1.

Images