Polypropylene material, preparation method and application thereof

Abstract

The application relates to the technical field of high polymer materials, in particular to a polypropylene material and a preparation method and application thereof, the polypropylene material comprises the following raw materials in parts by weight: 47-79 parts of polypropylene recycled resin, 5-25 parts of a toughening agent, 0-20 parts of talcum powder, 0.5-1.5 parts of a compatilizer, 2-15 parts of an adhesion composite reinforcing agent and 0.2-2.5 parts of an auxiliary agent. The polypropylene material has good mechanical properties and paint adhesion, and when the polypropylene material is used in plastic parts of an automobile, the adsorption capacity of the polypropylene material to paint can be enhanced, so that the polypropylene material is provided with the possibility of being free of primer spraying.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a polypropylene material and a preparation method and application thereof. Background Art

[0002] For automakers, incorporating green materials and processes into the design and development phase is not only essential for product upgrades and technological innovation, but also a manifestation of corporate social responsibility. Polypropylene accounts for the largest proportion of automotive plastics. The rational use of recycled polypropylene and its optimized application in the vehicle can effectively reduce the carbon footprint of automotive plastics.

[0003] Common polypropylene spray-coated automotive parts typically require a primer, basecoat, and topcoat to meet part requirements, resulting in significant costs. This is especially true when recycled polypropylene is used in the parts, which can lead to low impact strength and adhesion. Numerous studies have been conducted to reduce the cost of polypropylene spray-coated automotive parts, optimize the coating process, and improve the impact strength and adhesion of recycled polypropylene.

[0004] For example, Chinese patent application number CN202210518899.0 improves the impact strength of polypropylene recycled materials by adding nano-silica and ethylene-octene copolymer to achieve composite toughening. For example, Chinese patent publication number CN103627262A adds a nickel-ion-loaded talc powder to enhance the material's adhesion to paint, eliminating the need for a primer during spraying and simplifying the primer application process. Another example is Chinese patent application number CN109181118A, which improves the adhesion of PP substrates to paint by adding a highly active synergist and interfacial promoter, allowing for direct application of basecoat or topcoat. These solutions optimize the impact strength, paint adhesion, and spraying process, but they still have the following drawbacks: 1. The process of loading metal ions onto inorganic fillers is complex and suffers from poor stability; 2. The high activity of highly active materials makes the production process difficult to control; 3. The recycled materials suffer from poor paint removal, which seriously affects the mechanical properties and sprayability of the materials. Summary of the Invention

[0005] One of the purposes of the present invention is to provide a polypropylene material having good mechanical properties and paint adhesion, so that when the polypropylene material is used in plastic parts of automobiles, the polypropylene material's adsorption capacity for paint can be enhanced, thereby making it possible to avoid spraying primer on the polypropylene material; a second purpose is to provide a method for preparing the polypropylene material; and a third purpose is to provide an application of the polypropylene material.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A polypropylene material comprises the following raw materials in parts by weight: 47-79 parts of polypropylene recycled resin, 5-25 parts of toughening agent, 0-20 parts of talc powder, 0.5-1.5 parts of compatibilizer, 2-15 parts of adhesion composite enhancer, and 0.2-2.5 parts of auxiliary agent.

[0008] Preferably, the polypropylene recycled resin is made from waste household appliances, automobiles, and daily necessities, and the density of the polypropylene recycled resin is 0.9-0.94 g / cm 3 The Izod notched impact strength of the polypropylene recycled resin is 7-10 kJ / m 2 . Polypropylene recycled resin polypropylene content ≥95%.

[0009] More preferably, the polypropylene recycled resin is selected from the inner drum of a washing machine as the recycled raw material, and the density is 0.9-0.91g / cm 3 The inner drum of the washing machine contains fewer impurities, has higher purity, requires fewer recycling steps, and is more cost-effective. When choosing, you are not limited to recycled materials for the inner drum of the washing machine. Other recycled polypropylene materials that meet the requirements in terms of density, impact strength, polypropylene content, etc. can also be selected.

[0010] Further preferably, the density of the polypropylene recycled resin is 0.905 g / cm 3 .

[0011] Preferably, the toughening agent is a polyurethane resin, and the isocyanate index of the polyurethane resin is 1.6-2.2.

[0012] Further preferably, the isocyanate index of the polyurethane resin is 2.0. When the isocyanate index in the polyurethane resin is too high, the residual isocyanate will participate in the curing reaction, causing its dispersion in the polypropylene to deteriorate and the toughening effect to deteriorate; when the isocyanate index is too low, the molecular weight of the polyurethane resin is low and the toughening effect is also poor.

[0013] Preferably, the compatibilizer is one or more of PP-g-MAH, PP-g-GMA, POE-g-MAH, and POE-g-GMA, and the grafting rate of the compatibilizer is 0.6-1.5.

[0014] More preferably, the compatibilizer is maleic anhydride-grafted POE, with a grafting ratio of preferably 1.0. Because the grafting ratio affects material properties, a low grafting ratio results in poor compatibility between the polyurethane resin and the polypropylene resin, resulting in poor toughening. Therefore, using maleic anhydride-grafted POE with a grafting ratio of 1.0 in combination with the polyurethane resin achieves a better toughening effect on the polypropylene material.

[0015] Preferably, the composite adhesion enhancer comprises a porous filler, a reinforcing agent and a coupling agent, and the composite adhesion enhancer is prepared by mixing the porous filler, the reinforcing agent and the coupling agent.

[0016] Preferably, the porous filler is diatomaceous earth, zeolite powder, kaolin, ceramic powder and their mixtures, the reinforcing agent is graphene oxide, and the coupling agent is one or more of a silane coupling agent, a titanate coupling agent and an aluminate coupling agent.

[0017] More preferably, kaolin is used as the porous filler. Since kaolin has ion exchange properties and a porous structure, it can enhance the adsorption capacity of paint when used in paint. Silane coupling agent is used as the coupling agent.

[0018] Graphene oxide has a certain degree of conductivity, which is beneficial to improving the adsorption of paint on the surface of the material. It can adsorb paint well on the surface of polypropylene material. At the same time, the surface of graphene oxide contains oxygen-containing groups, which interact with the polar resin (polyurethane resin / epoxy resin / acrylic resin) in the paint, further improving the adhesion of the paint.

[0019] By using kaolin and graphene oxide as reinforcing agents and cross-linking kaolin and graphene oxide with a silane coupling agent, the compatibility of the adhesion composite enhancer with polypropylene recycled resin is enhanced, making the synergistic effect of kaolin and graphene oxide stronger, thereby improving the adhesion of paint on the plastic substrate and providing the possibility of primer-free spraying of polypropylene materials.

[0020] Preferably, the auxiliary agent includes an antioxidant and a light stabilizer, wherein the antioxidant is one or more of a hindered phenol antioxidant and a phosphite antioxidant, and the light stabilizer is a hindered amine light stabilizer.

[0021] Further preferably, the hindered phenol antioxidant and phosphite antioxidant are specifically one or more of antioxidant 1010, antioxidant 1076, antioxidant 3114, antioxidant 168, and antioxidant PEP-36. In this embodiment, a mixture of antioxidant 1010 and antioxidant 168 is preferably used, and the mass ratio of the two is 1:1.

[0022] Further preferably, the light stabilizer is one or both of UV-3808PP5 and LA-402AF. In this embodiment, the light stabilizer is UV-3808PP5, and the mass ratio of the light stabilizer to the antioxidant is 1:2.

[0023] The present application also discloses a method for preparing a polypropylene material, comprising the following steps: S10. quantitatively weighing polypropylene recycled resin, toughening agent, talcum powder, compatibilizer and auxiliary agent respectively and setting them aside; S20. placing the polypropylene recycled resin, toughening agent, talcum powder, compatibilizer and auxiliary agent in step S10 together in a mixer, mixing them evenly to obtain a premix; S30. weighing quantitative raw materials of a composite reinforcing agent respectively, placing them in a powdering machine respectively, and obtaining a composite reinforcing agent by powdering; S40. adding the premix in step S20 to a screw extruder through a main feeding port, and then adding the composite reinforcing agent to the screw extruder through a side feeding port, wherein the feeding frequency of the composite reinforcing agent is 10-20 Hz, and the shear force on the composite reinforcing agent in the screw extruder is less than the shear force on the premix; S50. extruding, granulating and cooling by a screw extruder to obtain a polypropylene material.

[0024] Preferably, in the step S30, the adhesion composite enhancer includes a porous filler, a reinforcing agent and a coupling agent. When processed in a powdering machine, the specific steps include: placing the porous filler and the reinforcing agent in the powdering machine, processing for 3-5 minutes, heating to 40-60°C, then adding the coupling agent, and continuing to process for 3-10 minutes to obtain the adhesion composite enhancer.

[0025] Further preferably, the feeding section temperature of the screw extruder is 190-205°C, 205-215°C, 215-225°C, 215-225°C, 215-225°C, 215-225°C, 215-225°C, 205-215°C, the head temperature is 215-225°C, and the screw speed is 300-600r / min.

[0026] Further preferably, the feeding section temperature of the twin-screw extruder is set to 200°C, 210°C, 220°C, 220°C, 220°C, 220°C, 220°C, 210°C, the head temperature is 220°C, and the screw speed is 400r / min.

[0027] More preferably, the particle size of the talc is 1-30 μm.

[0028] Further preferably, the screw extruder is a twin-screw extruder, and the twin-screw extruder is divided into nine intervals according to the number of barrel sections, wherein the side feed is located on the barrel in the fourth interval, and the main feed is located on the barrel in the ninth interval. In the twin-screw extruder, the 6th-7th interval is mainly used for stirring and shearing the premix, and the 3rd-4th interval is mainly used for stirring and shearing the premix and the adhesion composite enhancer, and the screw shear force in the fourth interval is less than the screw shear force in the ninth interval. When the premix enters the twin-screw extruder from the main feed port at the ninth interval and the adhesion composite enhancer enters the twin-screw extruder from the side feed port at the fourth interval, the screw shear force causes less damage to the adhesion composite enhancer than to the premix, so that the final polypropylene mixture is extruded from the first interval of the twin-screw extruder.

[0029] Since both the premix and the adhesion composite enhancer are fed by motor-driven feeding, the main feed is a motor-driven ordinary feeding hopper with a feeding frequency of 20-60Hz, and the side feed is a motor-driven forced feeding hopper with a feeding frequency of 10-20Hz. Under the condition of reducing the probability of the composite enhancer being destroyed, the adhesion composite enhancer and the premix are fully mixed.

[0030] By feeding the premix and composite enhancer separately and adding the adhesion composite enhancer at the weak shear position of the twin-screw extruder, the degree of damage to the structure of the adhesion composite enhancer caused by screw shear can be reduced, thereby increasing the number of adsorption points, which is beneficial to improving the adhesion of polypropylene materials to paint and increasing the possibility of realizing primer-free spraying process.

[0031] The present application also discloses an application of the above-mentioned polypropylene material, wherein the polypropylene material is used for manufacturing plastic parts, and the plastic parts include one of home appliances, daily necessities, automobile bumpers, side skirts, fenders, door outer guards, and body guards.

[0032] In practical applications, when polypropylene materials need to be sprayed with paint as other products or product parts, they can be used and can be selected according to actual needs.

[0033] The present application adopting the above solution has the following beneficial effects:

[0034] 1. By using waste home appliances, cars, and daily necessities as raw materials to make polypropylene recycled resin, the utilization rate of waste plastics can be improved. Then, by using polyurethane resin and maleic anhydride grafted POE as toughening agents, the toughness of polypropylene materials can be synergistically enhanced, and the compatibility of polyurethane and polypropylene can be improved, making the properties of polypropylene materials more stable. In addition, polyurethane resin contains isocyanate, which can interact with polyurethane resin / epoxy resin / acrylic resin commonly used in paint to improve the adhesion of paint; 2. By using kaolin and graphene oxide as composite reinforcement and combining the two with silane coupling agent, the two can be effectively strengthened. Cross-linking synergistically enhances the adhesion to paint, further improves the adhesion to paint, and enhances the compatibility of the adhesion composite enhancer with polypropylene recycled resin, so that the polypropylene material has stronger adhesion to the paint, increasing the possibility of achieving primer-free spraying; 3. In the process of preparing polypropylene materials, by adding the adhesion composite enhancer at the weak shear position of the twin-screw extruder, the degree of damage to the structure of the adhesion composite enhancer caused by screw shear can be reduced, thereby increasing the number of adsorption points, which is beneficial to the improvement of the adhesion of the polypropylene material to the paint and increases the possibility of achieving a primer-free spraying process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present application may be further illustrated by the non-limiting examples given in the accompanying drawings;

[0036] Figure 1 Schematic diagram of the structure of the main feed and side feed in the screw extruder in the embodiment of the present application; DETAILED DESCRIPTION

[0037] The following will be combined with the specific implementation methods in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All raw materials, equipment, or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0039] In this application, the density of polypropylene recycled resin is 0.905g / cm 3 , Izod notch impact strength 7-10kJ / m 2 The isocyanate index of the polyurethane resin is 2.0, the grafting rate of the maleic anhydride grafted POE is 1.0%, and the polypropylene content of the polypropylene recycled resin is ≥95%.

[0040] Example 1, Preparation of polypropylene material

[0041] S10. Quantitatively weigh 61 parts by mass of recycled polypropylene resin, 5 parts by mass of polyurethane resin, 15 parts by mass of talc, 1 part by mass of maleic anhydride grafted POE, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168, and 0.2 parts by mass of light stabilizer UV-3808PP5, respectively, and set aside; S20. The recycled polypropylene resin, polyurethane resin, talc, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168, and light stabilizer UV-3808PP5 in step S10 are placed together in a mixer and mixed uniformly to obtain a premix;

[0042] S30. Weigh 5 parts by mass of kaolin, 3 parts by mass of graphene oxide, and 0.5 parts by mass of a silane coupling agent, respectively. Place the kaolin and graphene oxide in a powder grinder, grind at low speed for 3-5 minutes, heat to 40-60°C, add the silane coupling agent, and continue grinding at low speed for 3-10 minutes to obtain a powdered adhesion enhancer. S40. Add the premix in step S20 to a twin-screw extruder through the main feed port, wherein (such as Figure 1 As shown), the main feeding port is located in the ninth interval of the feeding section of the twin-screw extruder, and the composite reinforcing agent in step S30 is added to the screw extruder through the side feeding port, wherein the side feeding port is located in the fourth interval of the feeding section of the twin-screw extruder, and the screw shearing force of the twin-screw extruder on the third to fourth intervals is less than the screw shearing force on the sixth to seventh intervals, so that the shearing force on the adhesion composite reinforcing agent is less than the shearing force on the premix, and the feeding frequency of the adhesion composite reinforcing agent is 10-20 Hz, the feeding frequency of the premix is ​​20-60 Hz, so that the composite additive and the premix are sheared by the screw and extruded from the first section; during the screw extrusion process, the temperatures of the twin-screw extruder are set to 200° C., 210° C., 220° C., 220° C., 220° C., 220° C., 220° C., and 210° C., respectively; the head temperature is 220° C., and the screw speed is 400 r / min; S50. Extrusion, granulation, and cooling are performed by the screw extruder to obtain a polypropylene material.

[0043] In this embodiment, polypropylene material can be used to manufacture plastic parts, which can be one or more of home appliances, daily necessities, car bumpers, side skirts, fenders, door exterior panels, and body panels. They can be manufactured according to actual needs and can also be used as other products or parts of products when spray painting is required.

[0044] Example 2, Preparation of Polypropylene Material II

[0045] S10. Quantitatively weigh 61 parts by mass of recycled polypropylene resin, 10 parts by mass of polyurethane resin, 15 parts by mass of talc, 1 part by mass of maleic anhydride grafted POE, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168, and 0.2 parts by mass of light stabilizer UV-3808PP5, respectively, and set aside; S20. The recycled polypropylene resin, polyurethane resin, talc, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168, and light stabilizer UV-3808PP5 in step S10 are placed together in a mixer and mixed uniformly to obtain a premix;

[0046] S30. Weigh 5 parts by mass of kaolin, 3 parts by mass of graphene oxide, and 0.5 parts by mass of a silane coupling agent, respectively. Place the kaolin and graphene oxide in a powder grinder, grind at low speed for 3-5 minutes, heat to 40-60°C, add the silane coupling agent, and continue grinding at low speed for 3-10 minutes to obtain a powdered adhesion enhancer. S40. Add the premix in step S20 to a twin-screw extruder through the main feed port, wherein (such as Figure 1 As shown), the main feeding port is located in the ninth interval of the feeding section of the twin-screw extruder, and the composite reinforcing agent in step S30 is added to the screw extruder through the side feeding port, wherein the side feeding port is located in the fourth interval of the feeding section of the twin-screw extruder, and the screw shearing force of the twin-screw extruder on the third to fourth intervals is less than the screw shearing force on the sixth to seventh intervals, so that the shearing force on the adhesion composite reinforcing agent is less than the shearing force on the premix, and the feeding frequency of the adhesion composite reinforcing agent is 10-20 Hz, the feeding frequency of the premix is ​​20-60 Hz, so that the composite additive and the premix are sheared by the screw and extruded from the first section; during the screw extrusion process, the temperatures of the twin-screw extruder are set to 200° C., 210° C., 220° C., 220° C., 220° C., 220° C., 220° C., and 210° C., respectively; the head temperature is 220° C., and the screw speed is 400 r / min; S50. Extrusion, granulation, and cooling are performed by the screw extruder to obtain a polypropylene material.

[0047] In this embodiment, polypropylene masterbatch can be used to manufacture plastic parts, which can be one or more of home appliances, daily necessities, car bumpers, side skirts, fenders, door exterior panels, and body panels. They can be manufactured according to actual needs and can also be used as other products or parts of products when spraying paint is required.

[0048] Example 3, Preparation of Polypropylene Material

[0049] S10. Quantitatively weigh 61 parts by mass of recycled polypropylene resin, 5 parts by mass of polyurethane resin, 15 parts by mass of talc, 1 part by mass of maleic anhydride grafted POE, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168, and 0.2 parts by mass of light stabilizer UV-3808PP5, respectively, and set aside; S20. The recycled polypropylene resin, polyurethane resin, talc, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168, and light stabilizer UV-3808PP5 in step S10 are placed together in a mixer and mixed uniformly to obtain a premix;

[0050] S30. Weigh 5 parts by mass of kaolin, 3 parts by mass of graphene oxide, and 0.5 parts by mass of a silane coupling agent, respectively. Place the kaolin and graphene oxide in a powder grinder, grind at low speed for 3-5 minutes, heat to 40-60°C, add the silane coupling agent, and continue grinding at low speed for 3-10 minutes to obtain a powdered adhesion enhancer. S40. Add the premix in step S20 to a twin-screw extruder through the main feed port, wherein (such as Figure 1 As shown), the main feeding port is located in the ninth interval of the feeding section of the twin-screw extruder, and the composite reinforcing agent in step S30 is added to the screw extruder through the side feeding port, wherein the side feeding port is located in the fourth interval of the feeding section of the twin-screw extruder, and the screw shearing force of the twin-screw extruder on the third to fourth intervals is less than the screw shearing force on the sixth to seventh intervals, so that the shearing force on the adhesion composite reinforcing agent is less than the shearing force on the premix, and the feeding frequency of the adhesion composite reinforcing agent is 10-20 Hz, the feeding frequency of the premix is ​​20-60 Hz, so that the composite additive and the premix are sheared by the screw and extruded from the first section; during the screw extrusion process, the temperatures of the twin-screw extruder are set to 200° C., 210° C., 220° C., 220° C., 220° C., 220° C., 220° C., and 210° C., respectively; the head temperature is 220° C., and the screw speed is 400 r / min; S50. Extrusion, granulation, and cooling are performed by the screw extruder to obtain a polypropylene material.

[0051] In this embodiment, polypropylene masterbatch can be used to manufacture plastic parts, which can be one or more of home appliances, daily necessities, car bumpers, side skirts, fenders, door exterior panels, and body panels. They can be manufactured according to actual needs and can also be used as other products or parts of products when spraying paint is required.

[0052] Example 4 (Comparative Example 1), Preparation of Polypropylene Material

[0053] S10. Quantitatively weigh 61 parts by mass of recycled polypropylene resin, 15 parts by mass of polyurethane resin, 20 parts by mass of talc, 1 part by mass of maleic anhydride grafted POE, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168, and 0.2 parts by mass of light stabilizer UV-3808PP5, respectively, and set aside; S20. The recycled polypropylene resin, polyurethane resin, talc, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168, and light stabilizer UV-3808PP5 in step S10 are placed together in a mixer and mixed uniformly to obtain a premix;

[0054] S30. Weigh 3 parts by mass of graphene oxide and 0.5 parts by mass of a silane coupling agent, add the graphene oxide and the silane coupling agent to a powder grinder, and grind them at a low speed for 3-10 minutes at 40-60°C to obtain a powdered adhesion enhancer composite; S40. The premix in step S20 is added to a twin-screw extruder through the main feed port, wherein (such as Figure 1 As shown), the main feeding port is located in the ninth interval of the feeding section of the twin-screw extruder, and the composite reinforcing agent in step S30 is added to the screw extruder through the side feeding port, wherein the side feeding port is located in the fourth interval of the feeding section of the twin-screw extruder, and the screw shearing force of the twin-screw extruder on the third to fourth intervals is less than the screw shearing force on the sixth to seventh intervals, so that the shearing force on the adhesion composite reinforcing agent is less than the shearing force on the premix, and the feeding frequency of the adhesion composite reinforcing agent is 10-20 Hz, the feeding frequency of the premix is ​​20-60 Hz, so that the composite additive and the premix are sheared by the screw and extruded from the first section; during the screw extrusion process, the temperatures of the twin-screw extruder are set to 200° C., 210° C., 220° C., 220° C., 220° C., 220° C., 220° C., and 210° C., respectively; the head temperature is 220° C., and the screw speed is 400 r / min; S50. Extrusion, granulation, and cooling are performed by the screw extruder to obtain a polypropylene material.

[0055] Example 5 (Comparative Example 2), Preparation of Polypropylene Material

[0056] S10. Quantitatively weigh 61 parts by mass of recycled polypropylene resin, 15 parts by mass of polyurethane resin, 18 parts by mass of talc, 1 part by mass of maleic anhydride grafted POE, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168, and 0.2 parts by mass of light stabilizer UV-3808PP5, respectively, and set aside; S20. The recycled polypropylene resin, polyurethane resin, talc, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168, and light stabilizer UV-3808PP5 in step S10 are placed together in a mixer and mixed uniformly to obtain a premix;

[0057] S30. Weigh 5 parts by mass of kaolin and 0.5 parts by mass of silane coupling agent, place the kaolin in a powder machine, grind it at low speed for 3-5 minutes, heat it to 40-60 ° C, add the silane coupling agent, and continue grinding it at low speed for 3-10 minutes to obtain a powdered adhesion enhancer; S40. The premix in step S20 is added to the twin-screw extruder through the main feed port, wherein (such as Figure 1 As shown), the main feeding port is located in the ninth interval of the feeding section of the twin-screw extruder, and the composite reinforcing agent in step S30 is added to the screw extruder through the side feeding port, wherein the side feeding port is located in the fourth interval of the feeding section of the twin-screw extruder, and the screw shearing force of the twin-screw extruder on the third to fourth intervals is less than the screw shearing force on the sixth to seventh intervals, so that the shearing force on the adhesion composite reinforcing agent is less than the shearing force on the premix, and the feeding frequency of the adhesion composite reinforcing agent is 10-20 Hz, the feeding frequency of the premix is ​​20-60 Hz, so that the composite additive and the premix are sheared by the screw and extruded from the first section; during the screw extrusion process, the temperatures of the twin-screw extruder are set to 200° C., 210° C., 220° C., 220° C., 220° C., 220° C., 220° C., and 210° C., respectively; the head temperature is 220° C., and the screw speed is 400 r / min; S50. Extrusion, granulation, and cooling are performed by the screw extruder to obtain a polypropylene material.

[0058] Example 6 (Comparative Example 3), Preparation of Polypropylene Material

[0059] S10. Quantitatively weigh 61 parts by mass of recycled polypropylene resin, 15 parts by mass of polyurethane resin, 15 parts by mass of talc, 1 part by mass of maleic anhydride grafted POE, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168, and 0.2 parts by mass of light stabilizer UV-3808PP5, respectively, and set aside; S20. The recycled polypropylene resin, polyurethane resin, talc, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168, and light stabilizer UV-3808PP5 in step S10 are placed together in a mixer and mixed uniformly to obtain a premix;

[0060] S30. Weigh 5 parts by mass of kaolin and 3 parts by mass of graphene oxide, place the kaolin and graphene oxide in a powder grinder, grind them at low speed for 3-5 minutes, heat to 40-60°C, and continue grinding at low speed for 3-10 minutes to obtain a powdered adhesion enhancer; S40. Add the premix in step S20 to a twin-screw extruder through the main feed port, wherein (such as Figure 1S30. The composite reinforcing agent in the step S20 is added into the twin-screw extruder through the main feeding port, wherein the main feeding port is located at the ninth interval of the feeding section of the twin-screw extruder, and the composite reinforcing agent is extruded from the first interval after being sheared by the screw; during the extrusion by the screw, the temperature of the feeding section of the twin-screw extruder is set to be 200 ℃, 210 ℃, 220 ℃, 220 ℃, 220 ℃, 220 ℃, 220 ℃, 220 ℃, 210 ℃, respectively, the temperature of the die head is 220 ℃, and the screw rotation speed is 400 r / min; S40. The polypropylene material is obtained by extruding, granulating and cooling through the twin-screw extruder.

[0061] Example 7 (Comparative Example 4), preparation of the polypropylene material

[0062] S10. 61 parts by mass of the polypropylene recycled resin, 15 parts by mass of the polyurethane resin, 21 parts by mass of the talcum powder, 1 part by mass of the maleic anhydride grafted POE, 0.2 parts by mass of the antioxidant 1010, 0.2 parts by mass of the antioxidant 168 and 0.2 parts by mass of the light stabilizer UV-3808PP5 are respectively weighed and prepared; S20. The polypropylene recycled resin, the polyurethane resin, the talcum powder, the maleic anhydride grafted POE, the antioxidant 1010, the antioxidant 168 and the light stabilizer UV-3808PP5 in the step S10 are placed in a mixer together and uniformly mixed to obtain a premix; S30. The premix in the step S20 is added into the twin-screw extruder through the main feeding port, wherein the main feeding port is located at the ninth interval of the feeding section of the twin-screw extruder, and the premix is extruded from the first interval after being sheared by the screw; during the extrusion by the screw, the temperature of the feeding section of the twin-screw extruder is set to be 200 ℃, 210 ℃, 220 ℃, 220 ℃, 220 ℃, 220 ℃, 220 ℃, 220 ℃, 210 ℃, respectively, the temperature of the die head is 220 ℃, and the screw rotation speed is 400 r / min; S40. The polypropylene material is obtained by extruding, granulating and cooling through the twin-screw extruder.

[0063] Example 8 (Comparative Example 5), preparation of the polypropylene material

[0064] S10. Respectively, 61 parts by mass of polypropylene recycled resin, 15 parts by mass of polyurethane resin, 15 parts by mass of talcum powder, 1 part by mass of maleic anhydride grafted POE, 0.2 parts by mass of antioxidant 1010, 0.2 parts by mass of antioxidant 168 and 0.2 parts by mass of light stabilizer UV-3808PP5 are weighed and prepared for use; S20. The polypropylene recycled resin, polyurethane resin, talcum powder, maleic anhydride grafted POE, antioxidant 1010, antioxidant 168 and light stabilizer UV-3808PP5 in step S10 are placed in a mixer and mixed uniformly to obtain a premix;

[0065] S30. Respectively, 5 parts by mass of kaolin, 3 parts by mass of graphene oxide and 0.5 parts by mass of silane coupling agent are weighed and prepared; the kaolin and graphene oxide are placed in a powdering machine and subjected to low-speed pulverization treatment for 3-5 min; the temperature is raised to 40-60℃; the silane coupling agent is added and the low-speed pulverization treatment is continued for 3-10 min to obtain a powdery adhesion composite reinforcing agent; S40. The adhesion composite reinforcing agent in step S30 and the premix in step S20 are simultaneously added to the twin-screw extruder through the main feeding port, wherein the main feeding port is located at the ninth interval of the feeding section of the twin-screw extruder, so that the adhesion composite reinforcing agent and the premix are extruded from the first interval after being subjected to screw shearing; during the screw extrusion process, the feeding section temperature of the twin-screw extruder is set to 200℃, 210℃, 220℃, 220℃, 220℃, 220℃, 220℃, 220℃, 210℃, respectively, the die temperature is 220℃, and the screw rotation speed is 400 r / min; S50. The polypropylene material is obtained by extrusion, granulation and cooling through the screw extruder.

[0066] In examples 1-8, the addition amount of each raw material is shown in the following table:

[0067]

[0068] From the above table, the addition of each material and the feeding mode in examples 1-8 can be more clearly understood, which helps to enhance the understanding of the scheme of the present application.

[0069] The polypropylene materials prepared in examples 1-8 are injection molded into sample strips and 100*100*3mm square plates for testing the flexural modulus, Izod notched impact and adhesion, wherein the flexural modulus is tested according to ISO 178 "Determination of the flexural properties of plastics"; the Izod notched impact strength is tested according to ISO 180 "Determination of the impact strength of plastics"; the adhesion is tested according to ISO 4624 "Pull-off test for adhesion of paint and varnish"; the test results are shown in the following table:

[0070]

[0071] From the above data, it can be seen that among Examples 1-3, in Example 3, the flexural modulus, notched cantilever impact strength and adhesion are the best, indicating that in the polypropylene material, when the polyurethane resin content is 15 parts, the maleic anhydride grafted POE content is 1 part, the graphene oxide is 3 parts, and the kaolin content is 5 parts, the obtained polypropylene material has the best comprehensive performance in notched impact strength, flexural modulus and adhesion.

[0072] From the comparison of the data of Example 3 and Example 4, it can be seen that the addition of kaolin helps to improve the Izod notched impact strength of the polypropylene recycled material, and the addition of kaolin can significantly affect the adhesion of the polypropylene material to the paint.

[0073] From the comparison of the data of Example 3 and Example 5, it can be seen that the addition of graphene oxide helps to improve the adhesion of polypropylene material to paint.

[0074] From the comparison of the data of Example 3 and Example 6, it can be seen that although the direct addition of kaolin and graphene oxide does not affect the adhesion of the polypropylene material to the paint, the flexural modulus and the notched cantilever beam impact strength of the polypropylene material are significantly reduced, indicating that the mechanical properties of the polypropylene material can be significantly improved after the kaolin and graphene oxide are treated with a silane coupling agent.

[0075] From the comparison of the data of Example 3 and Example 7, it can be seen that although the addition of the composite reinforcing agent reduces the flexural modulus and the notched cantilever impact strength of the polypropylene material, it significantly improves the adhesion of the polypropylene material to the paint, increasing the possibility of achieving primer-free spraying.

[0076] From the comparison of the data of Example 3 and Example 8, it can be seen that the adhesion composite enhancer is added to the twin-screw extruder by side feeding and added at a weak shear position, which can reduce the degree of damage to the composite enhancer structure caused by screw shear, thereby increasing the number of adsorption points and enhancing the paint adhesion of the polypropylene material.

[0077] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A polypropylene material, characterized in that: The invention comprises the following raw materials in parts by weight: 47-79 parts of polypropylene recycled resin, 5-25 parts of toughening agent, 0-20 parts of talc powder, 0.5-1.5 parts of compatibilizer, 2-15 parts of adhesion composite enhancer, and 0.2-2.5 parts of auxiliary agent; The polypropylene recycled resin is made from waste household appliances, automobiles, and daily necessities. The density of the polypropylene recycled resin is 0.9-0.94 g / cm 3 The Izod notched impact strength of the polypropylene recycled resin is 7-10 kJ / m 2 , the polypropylene content of the polypropylene recycled resin is ≥95%; The toughening agent is a polyurethane resin, and the isocyanate index of the polyurethane resin is 1.6-2.2; The adhesion composite enhancer includes a porous filler, a reinforcing agent and a coupling agent, and the adhesion composite enhancer is prepared by mixing the porous filler, the reinforcing agent and the coupling agent, wherein the reinforcing agent is graphene oxide, the porous filler is one of diatomaceous earth, zeolite powder, kaolin, and ceramic powder, and the coupling agent is one or more of a silane coupling agent, a titanate coupling agent, and an aluminate coupling agent; The compatibilizer is one or more of PP-g-MAH, PP-g-GMA, POE-g-MAH, and POE-g-GMA, and the grafting rate of the compatibilizer is 0.6-1.5%.

2. The polypropylene material according to claim 1, characterized in that The auxiliary agent includes an antioxidant and a light stabilizer. The antioxidant is one or more of a hindered phenol antioxidant and a phosphite antioxidant. The light stabilizer is a hindered amine light stabilizer.

3. A method for preparing the polypropylene material according to any one of claims 1 to 2, characterized in that: The following steps are involved: S10 were quantitatively weighed polypropylene recycled resin, toughening agent, talc, compatibilizer and additives, set aside; S20 The polypropylene recycled resin, toughening agent, talc, compatibilizer and additives in step S10 are placed together in a mixer and mixed to obtain a premix; S30 were weighed quantitative composite reinforcing agent raw materials, were placed in a powder machine, by powdering treatment to obtain a composite reinforcing agent; S40. The premix in step S20 is added to the screw extruder through the main feed port, and then the composite reinforcing agent is added to the screw extruder through the side feed port, the composite reinforcing agent is fed at a frequency of 10-20 Hz, and the shear force of the composite reinforcing agent in the screw extruder is less than the shear force of the premix; S50. Extruding, pelletizing, and cooling through a screw extruder to obtain a polypropylene material.

4. The method for preparing the polypropylene material according to claim 3, wherein: In the step S30, the adhesion composite enhancer includes a porous filler, a reinforcing agent and a coupling agent. When the powdering machine is used for treatment, the specific steps include: placing the porous filler and the reinforcing agent in the powdering machine, treating for 3-5 minutes, heating to 40-60° C., then adding the coupling agent, and continuing to treat for 3-10 minutes to obtain the adhesion composite enhancer.

5. A use of the polypropylene material according to claim 3, characterized in that: The polypropylene material is used for manufacturing plastic parts, and the plastic parts include one of household appliances, daily necessities, automobile bumpers, side skirts, fenders, door outer panels, and body panels.

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