Low-emission recycled polypropylene composite material for automotive interior and preparation method thereof

Abstract

The application discloses a low-emission recycled polypropylene composite material for automobile interior decoration and a preparation method thereof, and belongs to the technical field of high polymer composite materials. The polypropylene composite material comprises the following raw materials in parts by mass: 10-88 parts of polypropylene, 5-40 parts of recycled polypropylene, 0-20 parts of inorganic filler, 2-10 parts of calcium carbonate, 2-15 parts of toughening agent, 1-3 parts of odor removal agent and 0.5-3 parts of processing aid. The recycled polypropylene granules are ground into powder in a ball mill, and then cleaned in an ethanol aqueous solution to remove some small impurity components in the recycled polypropylene. The water injection equipment is used to inject dilute hydrochloric acid aqueous solution, the hydrochloric acid reacts with calcium carbonate in the polypropylene composite material to release carbon dioxide gas to extract part of small molecules, and the odor and volatile substances in the system are discharged together with water vapor in the processing process, so that the volatile substances and odor of the material are reduced.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, specifically relating to low-emission recycled polypropylene composite materials for automotive interiors and their preparation methods. Background Technology

[0002] Polypropylene (PP) is one of the five major general-purpose plastics, widely used in automobiles, home appliances, electronics, power tools, medical devices, and many other fields due to its excellent physical, chemical, mechanical, and processing properties. However, this also generates a large amount of waste plastic, making the utilization of this waste plastic a key theme for future development.

[0003] Currently, recycled polypropylene is already being used in some fields, such as automotive exterior bumpers and grilles. However, due to the high environmental requirements for automotive interior materials, and the emphasis on the health and olfactory experience of drivers and passengers, there are high requirements for the emission control of automotive interior materials. Recycled materials undergo multiple processing and degradation processes, and because additives or recycled materials are added to plastic products, these products often contain ethylene, hydrogen sulfide, sulfur dioxide, amines, ammonia, or other unpleasant odors. Some of these odors are released after the products have been stored for a period of time; sometimes they remain dormant within the plastic products, and these harmful gases are released during secondary processing, constituting the plastic's odor. Therefore, the application of recycled polypropylene in automotive interiors, such as door panels, dashboards, and pillars, is severely limited. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a low-emission recycled polypropylene composite material for automotive interiors and its preparation method, thereby solving the problems in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The low-emission recycled polypropylene composite material for automotive interiors comprises the following raw materials in parts by weight: 10-88 parts polypropylene, 5-40 parts recycled polypropylene, 0-20 parts inorganic filler, 2-10 parts calcium carbonate, 2-15 parts toughening agent, 1-3 parts deodorizer, and 0.5-3 parts processing aid.

[0007] Further, the polypropylene is at least one of homopolymer polypropylene, propylene-ethylene block copolymer, propylene-ethylene random copolymer, and propylene-1-butene random block copolymer.

[0008] Furthermore, the recycled polypropylene is at least one of the following: household appliance casing granulation material, battery casing crushing granulation material, and ton bag crushing granulation material.

[0009] Furthermore, the inorganic filler is at least one of talc, whiskers, mica, and wollastonite.

[0010] Furthermore, the toughening agent is at least one of POE, LLDPE, HDPE, and SEBS.

[0011] Furthermore, the deodorizing agent is a porous silicate.

[0012] Furthermore, the processing aid includes at least one of antioxidants, weathering agents, lubricants, and colorants.

[0013] The above-mentioned method for preparing low-emission recycled polypropylene composite materials for automotive interiors includes the following steps:

[0014] S1. Recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed with an ethanol-water solution to remove impurities and small molecules.

[0015] S2. Polypropylene, purified recycled polypropylene, inorganic filler, calcium carbonate, toughening agent, deodorizing agent, and processing aid are premixed evenly in a high-speed mixer in proportion to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt. Vacuum negative pressure is applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0016] Furthermore, the temperatures of the extruder zones one through ten are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; wherein a dilute hydrochloric acid aqueous solution is injected from the extruder zone three, and the concentration of the hydrochloric acid aqueous solution is 5–15 g / L; the vacuum negative pressure is -0.06 to -0.09 MPa.

[0017] The above-mentioned low-emission recycled polypropylene composite material for automotive interiors is used in the preparation of automotive interiors.

[0018] The beneficial effects of this invention are:

[0019] 1. This invention utilizes a liquid nitrogen atmosphere to grind recycled polypropylene granules into powder in a ball mill, and then washes them in an ethanol aqueous solution to remove some small impurities from the recycled polypropylene.

[0020] 2. This invention utilizes a dilute hydrochloric acid aqueous solution injected into a water injection device. The hydrochloric acid reacts with the calcium carbonate in the polypropylene composite material to release carbon dioxide gas, which extracts some small molecules. Together with water vapor, it removes odorous and volatile substances from the system during the processing, thereby reducing the volatile substances and odor of the material.

[0021] 3. The addition of porous silicate odor adsorbent in this invention can effectively lock small molecules that are not completely extracted by carbon dioxide and volatile substances that are not removed by water vapor in the porous structure, thereby playing a synergistic role in reducing the emissions of the composite material.

[0022] 4. The low-emission recycled polypropylene composite material prepared by this invention can be applied to automotive interior components such as door panels, dashboards, and pillars, expanding the scope of recycling of recycled polypropylene materials. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Low-emission recycled polypropylene composites for automotive interiors comprise the following parts by weight of raw materials:

[0025] Polypropylene 10-88 parts, recycled polypropylene 5-40 parts, inorganic filler 0-20 parts, calcium carbonate 2-10 parts, toughening agent 2-15 parts, deodorizing agent 1-3 parts, processing aid 0.5-3 parts;

[0026] Polypropylene is at least one of the following: homopolymer polypropylene, propylene-ethylene block copolymer, propylene-ethylene random copolymer, and propylene-1-butene random block copolymer.

[0027] Recycled polypropylene is at least one of the following: granulated material from the dismantling of household appliance casings, granulated material from the crushing of battery casings, and granulated material from the crushing of ton bags.

[0028] The inorganic filler is at least one of talc, whiskers, mica, and wollastonite.

[0029] The particle size of calcium carbonate is 2000 mesh or larger.

[0030] The toughening agent is at least one of POE, LLDPE, HDPE, and SEBS.

[0031] The deodorizer is a porous silicate.

[0032] At least one of the following processing aids: antioxidants, weathering agents, lubricants, and colorants.

[0033] The following examples illustrate the preparation process of low-emission recycled polypropylene composite materials for automotive interiors; all parts mentioned in the examples and comparative examples are by weight; the raw materials used in the examples are as follows:

[0034] Polypropylene, grade M60RHC, copolymer polypropylene, Zhenhai Refining & Chemical;

[0035] Recycled polypropylene, battery casing material, Jiangxi GEM Co., Ltd.

[0036] Talc powder, 1250 mesh talc powder 90-20-A, Guangxi Longsheng Huamei Talc;

[0037] Calcium carbonate, activated calcium carbonate 053B, particle size 2500 mesh, Jiangsu Qunxin Powder;

[0038] Toughening agent, POE, grade LC565, LG Chem;

[0039] Porous silicate, grade JH-200A, with an average pore size of 5nm, produced by Ningbo Jiahe New Materials.

[0040] The processing aids are commercially available conventional aids:

[0041] Antioxidant 1010, BASF;

[0042] Antioxidant 168, BASF;

[0043] Lubricant calcium stearate, grade CV500, Dongguan Hanwei Technology Co., Ltd.

[0044] Lubricant silicone masterbatch, grade BZPP301, Chongqing Baozhuan New Material Technology Co., Ltd.

[0045] Light stabilizer, grade 3808PP5, cyanide.

[0046] Example 1

[0047] The preparation process for low-emission recycled polypropylene composites used in automotive interiors includes:

[0048] S1. The recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0049] S2. 88 parts polypropylene, 5 parts recycled polypropylene, 2 parts calcium carbonate, 2 parts toughening agent POE, 1 part deodorizer (porous silicate), 0.2 parts antioxidant 1010, and 0.3 parts antioxidant 168 are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.06 MPa is then applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0050] The temperatures of the extruder zones 1 to 10 are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; the dilute hydrochloric acid aqueous solution is injected from the extruder zone 3, and the concentration of the hydrochloric acid aqueous solution is 5g / L.

[0051] Example 2

[0052] The preparation process for low-emission recycled polypropylene composites used in automotive interiors includes:

[0053] S1. The recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0054] S2. 72 parts polypropylene, 10 parts recycled polypropylene, 5 parts talc, 4 parts calcium carbonate, 5 parts toughening agent POE, 2 parts deodorizing agent (porous silicate), 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts lubricant calcium stearate, 0.3 parts lubricant silicone masterbatch, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.07 MPa is then applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0055] The temperatures of the extruder zones 1 to 10 are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; the dilute hydrochloric acid aqueous solution is injected from the extruder zone 3, and the concentration of the hydrochloric acid aqueous solution is 10g / L.

[0056] Example 3

[0057] The preparation process for low-emission recycled polypropylene composites used in automotive interiors includes:

[0058] S1. The recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0059] S2. 50 parts polypropylene, 20 parts recycled polypropylene, 10 parts talc, 6 parts calcium carbonate, 10 parts toughening agent POE, 2 parts deodorizing agent (porous silicate), 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts lubricant calcium stearate, 0.3 parts lubricant silicone masterbatch, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.08 MPa is then applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0060] The temperatures of the extruder zones 1 to 10 are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; the dilute hydrochloric acid aqueous solution is injected from the extruder zone 3, and the concentration of the hydrochloric acid aqueous solution is 15g / L.

[0061] Example 4

[0062] The preparation process for low-emission recycled polypropylene composites used in automotive interiors includes:

[0063] S1. The recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0064] S2. 22 parts polypropylene, 30 parts recycled polypropylene, 15 parts talc, 8 parts calcium carbonate, 15 parts toughening agent POE, 3 parts deodorizing agent (porous silicate), 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts lubricant calcium stearate, 1 part lubricant silicone masterbatch, 0.3 parts light stabilizer, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.09 MPa is then applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0065] The temperatures of the extruder zones 1 to 10 are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; the dilute hydrochloric acid aqueous solution is injected from the extruder zone 3, and the concentration of the hydrochloric acid aqueous solution is 15g / L.

[0066] Example 5

[0067] The preparation process for low-emission recycled polypropylene composites used in automotive interiors includes:

[0068] S1. The recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0069] S2. 10 parts polypropylene, 40 parts recycled polypropylene, 20 parts talc, 10 parts calcium carbonate, 10 parts toughening agent POE, 3 parts deodorizing agent (porous silicate), 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts lubricant calcium stearate, 1 part lubricant silicone masterbatch, 0.3 parts light stabilizer, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.09 MPa is then applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0070] The temperatures of the extruder zones 1 to 10 are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; the dilute hydrochloric acid aqueous solution is injected from the extruder zone 3, and the concentration of the hydrochloric acid aqueous solution is 15g / L.

[0071] The specific raw material formulations for Examples 1-5 are shown in Table 1.

[0072] Table 1. Raw material formulations in Examples 1-5

[0073]

[0074]

[0075] Comparative Example 1

[0076] The preparation process of polypropylene composite materials includes:

[0077] 40 parts of polypropylene, 20 parts of recycled polypropylene, 10 parts of talc, 6 parts of calcium carbonate, 15 parts of toughening agent, 2 parts of deodorizing agent, 0.2 parts of antioxidant 1010, 0.3 parts of antioxidant 168, 0.2 parts of calcium stearate lubricant, 0.3 parts of silicone masterbatch lubricant, and 1 part of black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.08 MPa is applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0078] The temperatures of zones one through ten of the extruder are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively. A dilute hydrochloric acid aqueous solution with a concentration of 15 g / L is injected from zone three of the extruder.

[0079] Comparative Example 2

[0080] The preparation process of polypropylene composite materials includes:

[0081] S1. The recycled polypropylene is washed in a 50% ethanol aqueous solution to remove impurities and small molecules;

[0082] S2. 40 parts polypropylene, 20 parts recycled polypropylene, 10 parts talc, 6 parts calcium carbonate, 15 parts toughening agent, 2 parts deodorizing agent, 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts calcium stearate lubricant, 0.3 parts silicone masterbatch lubricant, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.08 MPa is then applied. The mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0083] The temperatures of zones one through ten of the extruder are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively. A dilute hydrochloric acid aqueous solution with a concentration of 15 g / L is injected from zone three of the extruder.

[0084] Comparative Example 3

[0085] The preparation process of polypropylene composite materials includes:

[0086] S1. Recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0087] S2. 40 parts polypropylene, 20 parts recycled polypropylene, 16 parts talc, 15 parts toughening agent, 2 parts deodorizing agent, 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts calcium stearate lubricant, 0.3 parts silicone masterbatch lubricant, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.08 MPa is then applied. The mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0088] The temperatures of zones one through ten of the extruder are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively. A dilute hydrochloric acid aqueous solution with a concentration of 15 g / L is injected from zone three of the extruder.

[0089] Comparative Example 4

[0090] The preparation process of polypropylene composite materials includes:

[0091] S1. Recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0092] S2. 40 parts polypropylene, 20 parts recycled polypropylene, 10 parts talc, 6 parts calcium carbonate, 15 parts toughening agent, 2 parts deodorizing agent, 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts calcium stearate lubricant, 0.3 parts silicone masterbatch lubricant, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and distilled water is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.08 MPa is applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0093] The temperatures of the extruder zones 1 to 10 are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; distilled water is injected from the extruder zone 3.

[0094] Comparative Example 5

[0095] The preparation process of polypropylene composite materials includes:

[0096] S1. Recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0097] S2. 40 parts polypropylene, 20 parts recycled polypropylene, 10 parts talc, 6 parts calcium carbonate, 15 parts toughening agent, 2 parts deodorizing agent, 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts calcium stearate lubricant, 0.3 parts silicone masterbatch lubricant, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and the vacuum negative pressure is turned on to -0.08 MPa. The mixture is then extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0098] The temperatures of the extruder zones 1 to 10 are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively.

[0099] Comparative Example 6

[0100] The preparation process of polypropylene composite materials includes:

[0101] S1. The recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed in a 50% ethanol aqueous solution to remove impurities and small molecules.

[0102] S2. 52 parts polypropylene, 20 parts recycled polypropylene, 10 parts talc, 6 parts calcium carbonate, 10 parts toughening agent POE, 0.2 parts antioxidant 1010, 0.3 parts antioxidant 168, 0.2 parts lubricant calcium stearate, 0.3 parts lubricant silicone masterbatch, and 1 part black masterbatch are premixed evenly in a high-speed mixer to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt using a water injection device. A vacuum negative pressure of -0.08 MPa is then applied, and the mixture is extruded, granulated, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

[0103] The temperatures of the extruder zones 1 to 10 are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; the dilute hydrochloric acid aqueous solution is injected from the extruder zone 3, and the concentration of the hydrochloric acid aqueous solution is 15g / L.

[0104] Experimental Test

[0105] The polypropylene composite materials obtained in Examples 1-5 and Comparative Examples 1-5 were subjected to tests including tensile strength, elongation at break, notched impact strength, odor level, and fogging. It is worth noting that these tests are familiar to those skilled in the art, and the specific test methods are not detailed here. The test results are shown in Table 2 below.

[0106] Table 2. Test results of polypropylene composite materials in Examples 1-5 and Comparative Examples 1-6.

[0107]

[0108]

[0109] As can be seen from the data in Table 2 above, the recycled polypropylene composite material prepared by ball milling the recycled polypropylene into powder under liquid nitrogen conditions and washing it in an ethanol aqueous solution to remove impurities and small molecules, and by injecting a dilute hydrochloric acid aqueous solution into the extruder during the extrusion granulation process, utilizes the reaction of dilute hydrochloric acid and calcium carbonate in the twin-screw extruder to generate carbon dioxide gas to extract some small molecules, and together with water vapor, discharges odorous and volatile substances during the processing, and under the synergistic adsorption effect of porous silicates, not only has good basic physical properties, but also exhibits excellent low emission, with low odor level and low atomization value.

[0110] As can be seen from Example 3 and Comparative Examples 1 and 2, even with ethanol-water solution, the recycled polypropylene that has not been treated by liquid nitrogen atmosphere ball milling cannot remove impurities and small molecules. Therefore, the prepared recycled polypropylene composite material not only has poor odor and high fogging value, but also shows a certain trend of reduced basic mechanical properties. This is due to the negative impact of small molecule impurities on the system performance. The results of Example 3 and Comparative Examples 3, 4, and 5 show that when calcium carbonate powder is not added to the composite material system, or when dilute hydrochloric acid solution is not injected during processing, carbon dioxide gas cannot be formed to extract small molecules, thus failing to achieve good low-emission properties. Simply injecting distilled water cannot completely remove all volatile substances. The results of Example 3 and Comparative Example 6 show that without the synergistic effect of porous silicate odor adsorbent, some low-molecular-weight volatiles are not completely extracted or vaporized, leading to poor odor and high fogging value in the final composite material. Adding porous silicate odor adsorbent can synergistically adsorb the residual low-molecular-weight volatiles. Based on the above summary, compared with the comparative example, the present invention significantly improves odor while maintaining excellent material properties. Therefore, the polypropylene composite material prepared by the present invention can be applied to automotive interior products to meet different customer odor requirements.

[0111] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0112] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A low-emission recycled polypropylene composite material for automotive interiors, characterized in that, The raw materials include the following parts by weight: 10-88 parts polypropylene, 5-40 parts recycled polypropylene, 0-20 parts inorganic filler, 2-10 parts calcium carbonate, 2-15 parts toughening agent, 1-3 parts deodorizer, and 0.5-3 parts processing aid. The method for preparing the recycled polypropylene composite material includes the following steps: Regenerated polypropylene was ball-milled into powder under liquid nitrogen conditions and then washed with an ethanol-water solution to remove impurities and small molecules. Polypropylene, purified recycled polypropylene, inorganic fillers, calcium carbonate, toughening agent, deodorizing agent, and processing aids are premixed evenly in a high-speed mixer in a certain proportion to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt. Vacuum negative pressure is applied, and the mixture is extruded, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

2. The low-emission recycled polypropylene composite material for automotive interiors according to claim 1, characterized in that, The polypropylene is at least one of the following: homopolymer polypropylene, propylene-ethylene block copolymer, propylene-ethylene random copolymer, and propylene-1-butene random block copolymer.

3. The low-emission recycled polypropylene composite material for automotive interiors according to claim 1, characterized in that, The recycled polypropylene is at least one of the following: granulated material from household appliance casings, granulated material from crushed battery casings, and granulated material from crushed ton bags.

4. The low-emission recycled polypropylene composite material for automotive interiors according to claim 1, characterized in that, The inorganic filler is at least one of talc, whiskers, mica, and wollastonite.

5. The low-emission recycled polypropylene composite material for automotive interiors according to claim 1, characterized in that, The toughening agent is at least one of POE, LLDPE, HDPE, and SEBS.

6. The low-emission recycled polypropylene composite material for automotive interiors according to claim 1, characterized in that, The deodorizing agent is a porous silicate.

7. The low-emission recycled polypropylene composite material for automotive interiors according to claim 1, characterized in that, The processing aid is at least one of the following: antioxidant, weather resistant agent, lubricant, and colorant.

8. The method for preparing low-emission recycled polypropylene composite material for automotive interiors according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Recycled polypropylene is ball-milled into powder under liquid nitrogen conditions and then washed with an ethanol-water solution to remove impurities and small molecules. S2. Polypropylene, purified recycled polypropylene, inorganic filler, calcium carbonate, toughening agent, deodorizer, and processing aid are premixed evenly in a high-speed mixer in proportion to obtain a premix. The premix is ​​then placed in a twin-screw extruder, and a dilute hydrochloric acid aqueous solution is injected into the extruder melt. Vacuum negative pressure is applied, and the mixture is extruded, cooled, and pelletized to obtain a low-emission recycled polypropylene composite material.

9. The method for preparing low-emission recycled polypropylene composite material for automotive interiors according to claim 8, characterized in that, The temperatures of the extruder zones one through ten are 160℃, 210℃, 210℃, 210℃, 200℃, 200℃, 200℃, 200℃, 200℃, and 210℃, respectively; a dilute hydrochloric acid aqueous solution is injected from the extruder zone three, with a concentration of 5~15g / L; and the vacuum negative pressure is -0.06~-0.09MPa.

10. The use of the low-emission recycled polypropylene composite material for automotive interiors according to any one of claims 1-7 in the preparation of automotive interiors.

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