A polypropylene composition, its preparation method and application

Abstract

This invention relates to a polypropylene composition, its preparation method, and its application. The polypropylene composition comprises: 54-92 parts of polypropylene resin, 0.01-31 parts of filler, 0.01-16 parts of elastomer, and 0.4-2.3 parts of sodium bicarbonate. The sodium bicarbonate is added in the form of a sodium bicarbonate solution, wherein the mass concentration of sodium bicarbonate in the solution is 2-15%. This invention utilizes the characteristic of sodium bicarbonate to release carbon dioxide upon thermal decomposition, introducing carbon dioxide into the material. It combines the extremely high saturated vapor pressure and excellent solubility of carbon dioxide with stripping and volatilization technology to efficiently remove volatile odor substances from the product, reducing the product's odor level. Simultaneously, it can also reduce the product's gloss, meeting the application requirements in automotive interiors.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a polypropylene composition, its preparation method, and its application. Background Technology

[0002] Polypropylene (PP) is a polymer compound obtained by polymerizing propylene. Due to its abundant raw materials and relatively simple synthesis process, PP has a lower relative density and price compared to other general-purpose thermoplastics. It also exhibits outstanding stress resistance, crack resistance, and abrasion resistance. It is the fastest-growing variety of general-purpose thermoplastics, playing an increasingly important role in economic development and people's lives. It has become the fastest-growing plastic in terms of production volume and is widely used in automobiles, home appliances, daily necessities, and packaging, among other fields.

[0003] The interior environment of a car is crucial to the brand image and consumers' first impression, and automakers need to improve quality as a standard to meet and a selling point. In recent years, automakers have been increasing their demands for odor control in car interiors. For example, the odor requirements for polypropylene materials used in car interiors, such as door panels, have gradually increased from level 4.2 to below level 3.5 over the past decade (evaluation standard reference: Volkswagen PV3900).

[0004] The odor of polypropylene materials has complex origins. Factors such as residual catalysts and solvents from the polymerization of the matrix resin, incompletely polymerized small molecules, various additives used in processing and modification, and processing degradation can all contribute to increased PP odor. Currently, the main methods for reducing the odor of polypropylene materials are baking the material after extrusion and adding stripping agents such as water during extrusion for stripping and devolatilization. For example, CN104311999A discloses a low-odor polypropylene material and its preparation method, comprising the following components: 100 parts of recycled polypropylene; 10-40 parts of talc; 5-15 parts of superabsorbent polymer (SAP); 3-8 parts of water; 1-5 parts of reactive castor oil; 2-5 parts of heat stabilizer; and 2-5 parts of composite antioxidant. The method utilizes the vaporization of water in the SAP and additionally added water during melt processing to remove odor-producing small molecules from the polypropylene material, thereby preparing a low-odor polypropylene material. Furthermore, the active functional groups of the reactive castor oil chelate amines, sulfur compounds, and thiols in the material to form stable novel compounds, thus improving the material's odor. Moreover, the synergistic effect of the components optimizes the mechanical properties of the resulting polypropylene material. However, using stripping agents other than water has certain drawbacks in terms of safety and cost, and it can no longer meet the increasingly stringent odor requirements of the industry.

[0005] Therefore, there is an urgent need in the field to develop a low-odor polypropylene composition that is simple, efficient, safe, and inexpensive to prepare. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a polypropylene composition comprising polypropylene resin, filler, elastomer, and sodium bicarbonate solution. Using sodium bicarbonate as a carrier, the carbon dioxide is introduced into the production process by utilizing its decomposition and release of carbon dioxide. This combines stripping and volatilization technology with the extremely high saturated vapor pressure and excellent solubility of carbon dioxide to achieve a rapid dissolution-vaporization process during production. This efficiently removes volatile odor substances from the product, reducing its odor level. The method is simple, safe, and highly applicable.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a polypropylene composition, comprising, by weight: 54-92 parts of polypropylene resin, 0.01-31 parts of filler, 0.01-16 parts of elastomer, and 0.4-2.3 parts of sodium bicarbonate; wherein the sodium bicarbonate solution is added in the form of a sodium bicarbonate solution, and the mass concentration of sodium bicarbonate in the sodium bicarbonate is 2-15%.

[0009] The polypropylene composition provided by this invention includes sodium bicarbonate, which decomposes upon heating during production to release carbon dioxide. Carbon dioxide has the characteristics of high saturated vapor pressure and high solubility. Using it as a stripping agent, through stripping and devolatilization technology, carbon dioxide and odor substances in the polymer collide and dissolve during the extrusion process, efficiently nucleating, growing, breaking down, and entering the gas phase, thereby removing volatiles from the polymer melt.

[0010] This invention uses sodium bicarbonate as a carbon dioxide carrier and introduces it into extrusion production. On the one hand, the raw material is inexpensive and readily available, reducing production costs and solving the problem of difficulty in adding carbon dioxide fluid to the extruder. On the other hand, sodium bicarbonate differs from calcium bicarbonate or magnesium bicarbonate. Calcium bicarbonate or magnesium bicarbonate is not stable enough and often decomposes itself before being added to the polymer melt. Moreover, when prepared as an aqueous solution, both produce insoluble solid precipitates similar to scale after hydrolysis, which will quickly clog equipment pipes. Sodium bicarbonate, on the other hand, is more stable and decomposes to produce carbon dioxide at a suitable temperature, which is more effective in removing volatile odor substances. The overall process is efficient, safe, and has low operating and maintenance costs. In addition, the applicant found that adding a specific concentration of sodium bicarbonate can also significantly reduce the gloss of the manufactured parts.

[0011] The polypropylene resin is 54-92 parts, for example, 55 parts, 58 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 85 parts, 88 parts, or 90 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0012] The filler is 0.01-31 parts, for example, it can be 1 part, 2 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 28 parts or 30 parts, and specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0013] The elastomer is 0.01-16 parts, for example, it can be 0.05 parts, 0.1 parts, 0.2 parts, 0.5 parts, 1 part, 2 parts, 5 parts, 8 parts, 10 parts, 12 parts or 15 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0014] In this invention, the sodium bicarbonate content is 0.4 to 2.3 parts, for example, it can be 0.4 parts, 0.42 parts, 0.45 parts, 0.48 parts, 0.5 parts, 0.52 parts, 0.55 parts, 0.58 parts, 0.6 parts, 0.62 parts, 0.65 parts, 0.68 parts, 0.7 parts, 0.72 parts, 0.75 parts, 0.78 parts, 0.8 parts, 0.82 parts, 0.85 parts, 0.88 parts, 0.9 parts, 0.92 parts, 0.95 parts, or 0.98 parts. The amounts are 1 part, 1.1 part, 1.15 part, 1.2 part, 1.25 part, 1.3 part, 1.35 part, 1.4 part, 1.45 part, 1.5 part, 1.55 part, 1.6 part, 1.65 part, 1.7 part, 1.8 part, 1.9 part, 2 part, 2.1 part, 2.2 part, or 2.3 part, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range; preferably, it is 0.8 to 1.6 parts.

[0015] The sodium bicarbonate solution has a mass concentration of 2-15%, for example, 3%, 4%, 5%, 6%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 11.8%, 12%, 12.5%, 12.8%, 13%, 13.5%, 13.8%, 14%, 14.2%, 14.5%, 14.8%, 15%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range; more preferably, it is 7.5% to 13.5%.

[0016] In this invention, the sodium bicarbonate solution is 3.3-15.2 parts by weight, for example, 3.3 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5 parts, 5.2 parts, 5.5 parts, 5.8 parts, 6 parts, 6.2 parts, 6.5 parts, 6.8 parts, 7 parts, 7.2 parts, 7.5 parts, 7.8 parts, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.2 parts, 9.5 parts, 9.8 parts, 10 parts, or 10 parts. 2 parts, 10.5 parts, 10.8 parts, 11 parts, 11.2 parts, 11.5 parts, 11.8 parts, 12 parts, 12.2 parts, 12.5 parts, 12.8 parts, 13 parts, 13.2 parts, 13.5 parts, 13.8 parts, 14 parts, 14.2 parts, 14.5 parts, 14.8 parts, 15 parts, and specific point values ​​between the above point values, are not exhaustively listed in this invention due to space limitations and for the sake of brevity; more preferably, 6 to 13 parts.

[0017] In this invention, if the sodium bicarbonate content is low or the concentration of the sodium bicarbonate solution is too low, the improvement in odor is not obvious, and the product has high gloss. If the content or concentration is too high, the odor substances cannot be smoothly discharged due to excessive or rapid gas release, which will also lead to a worse odor and increased gloss.

[0018] In this invention, the "parts" and "parts by weight" of the non-solution components are calculated based on solid content and do not include solvents, dispersants, media, etc.

[0019] Preferably, the mass ratio of the polypropylene resin to sodium bicarbonate is (50-90):1, for example, it can be 50:1, 52:1, 55:1, 58:1, 60:1, 62:1, 65:1, 68:1, 70:1, 72:1, 75:1, 78:1, 80:1, 82:1, 85:1 or 88:1, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0020] As a preferred embodiment of the present invention, when the mass ratio of polypropylene resin to sodium bicarbonate is (50-90):1, the low-odor polypropylene obtained from the polypropylene composition has a lower odor level, which is more in line with the development direction of the automotive industry for interior materials.

[0021] Preferably, the mass ratio of sodium bicarbonate to filler is 1:(4-20), for example, it can be 1:4, 1:5, 1:6, 1:8, 1:10, 1:12, 1:14, 1:15, 1:16 or 1:18, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0022] This invention employs different filler contents to meet the needs of various products. However, fillers have a negative impact on odor; that is, increasing the filler ratio leads to a higher odor level. Therefore, this invention optimizes the filler addition ratio to obtain a polypropylene product with a lower odor level, making it suitable for applications in automotive interiors.

[0023] Preferably, the solvent of the sodium bicarbonate solution includes water.

[0024] Preferably, the polypropylene resin is copolymer polypropylene.

[0025] Preferably, the copolymerized polypropylene comprises a propylene-ethylene copolymer.

[0026] Preferably, the molar content of propylene-based structural units in the propylene-ethylene copolymer is 85-95%, for example, it can be 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93% or 94%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0027] Preferably, the melt index of the polypropylene resin is 30-100 g / 10 min, for example, it can be 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 55 g / 10 min, 60 g / 10 min, 65 g / 10 min, 70 g / 10 min, 75 g / 10 min, 80 g / 10 min, 85 g / 10 min, 90 g / 10 min or 95 g / 10 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0028] The melt flow index described in this invention was determined at 230°C and with a 2.16 kg weight, in accordance with ISO 1133-1:2022 standard.

[0029] Preferably, the filler comprises any one or a combination of at least two of talc, mica, or wollastonite, and more preferably talc.

[0030] Preferably, the particle size of the talc powder is 1000-3000 mesh, for example, it can be 1200 mesh, 1500 mesh, 1800 mesh, 2000 mesh, 2200 mesh, 2500 mesh or 2800 mesh, and specific particle values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific particle values ​​included in the range.

[0031] Preferably, the elastomer comprises a polyolefin elastomer.

[0032] Preferably, the polyolefin elastomer comprises ethylene-butene copolymer and / or ethylene-octene copolymer.

[0033] Preferably, the polypropylene composition further includes 0.2-1 parts by weight of antioxidant, for example, 0.25 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts or 0.9 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but is more preferably 0.4-0.6 parts.

[0034] Preferably, the antioxidant comprises a combination of a primary antioxidant and a secondary antioxidant.

[0035] Preferably, the mass ratio of the primary antioxidant to the secondary antioxidant is 1:(0.8-1.2), for example, it can be 1:0.85, 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1, or 1:1.15, as well as specific values ​​between the above-mentioned values. For space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. Preferably, the primary antioxidant includes hindered phenolic antioxidants.

[0036] Preferably, the hindered phenolic antioxidant includes any one or a combination of at least two of antioxidants 1010, 1076, 330, or 1790.

[0037] Preferably, the auxiliary antioxidant includes phosphite antioxidants.

[0038] Preferably, the phosphite antioxidant includes antioxidant 168 and / or antioxidant 627A.

[0039] In a second aspect, the present invention provides a low-odor polypropylene, which is prepared from the polypropylene composition described in the first aspect.

[0040] Thirdly, the present invention provides a method for preparing low-odor polypropylene as described in the second aspect, characterized in that the preparation method comprises the following steps:

[0041] Sodium bicarbonate is dissolved in water to obtain a sodium bicarbonate solution; the sodium bicarbonate solution is mixed with polypropylene resin, filler, elastomer, optional primary antioxidant, and optional secondary antioxidant, and then extruded to obtain the low-odor polypropylene.

[0042] The low-odor polypropylene preparation method provided by this invention utilizes the characteristic that sodium bicarbonate is easily soluble in water. Sodium bicarbonate is added in the form of an aqueous solution instead of sodium bicarbonate powder, which effectively ensures good dispersion of sodium bicarbonate. This facilitates the contact between the carbon dioxide produced by its decomposition and the odor substances in the polymer, thereby removing the volatiles from the polymer melt.

[0043] Preferably, the sodium bicarbonate solution has a sodium bicarbonate mass concentration of 2-15%, for example, 3%, 4%, 5%, 6%, 8%, 10%, 12% or 14%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. More preferably, it is 8-12%.

[0044] Preferably, the extrusion is carried out in a twin-screw extruder. Preferably, the extrusion temperature is 190-250°C, for example, 200°C, 210°C, 220°C, 230°C or 240°C, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0045] Preferably, the twin-screw extruder includes 10-13 screw barrel sections, for example, 10, 11, 12, 13, etc. Preferably, the temperature of the twin-screw extruder is set as follows: Section 1 200-220℃; Section 2 240-260℃; Section 3 220-240℃; Section 4 200-220℃; Section 5 190-210℃; Sections 6-13 are each independently set to 180-200℃.

[0046] Preferably, the mixing includes injecting a sodium bicarbonate solution into sections 3-7 of the screw, for example, sections 4, 5, or 6.

[0047] This invention achieves a further improvement in odor effect by injecting sodium bicarbonate solution into sections 3-7 of the screw. When sodium bicarbonate is added earlier or later, the volatilization effect is weaker, which affects the odor grade of the product.

[0048] Fourthly, the present invention provides the application of a polypropylene composition as described in the first aspect or a low-odor polypropylene as described in the second aspect in automotive interiors.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] This invention provides a polypropylene composition that utilizes the high saturated vapor pressure and high solubility of carbon dioxide as the main stripping agent. By leveraging the thermal decomposition of sodium bicarbonate to release carbon dioxide, carbon dioxide is introduced into the material. Combined with stripping and devolatilization technology, during extrusion, volatiles and the stripping agent nucleate, grow, and break down, entering the gas phase and removing volatiles from the polymer melt, thus reducing the product's odor level. The resulting low-odor polypropylene has a low odor rating. Furthermore, the applicant discovered that adding a specific concentration of sodium bicarbonate can significantly reduce the gloss of the manufactured parts, effectively reducing the "plastic feel" of automotive interior parts. This method is simple, efficient, inexpensive, safe, and widely applicable. Detailed Implementation

[0051] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0052] In the following specific embodiments of the present invention, the materials involved are as follows:

[0053] 1) Polypropylene resin

[0054] EP548R, a copolymer polypropylene resin, with a melt flow index of 30 g / 10 min (230℃, 2.16 kg weight), provided by CNOOC Shell.

[0055] EP640V, a copolymer polypropylene resin, with a melt flow index of 100 g / 10 min (230℃, 2.16 kg weight), provided by CNOOC Shell.

[0056] 2) Packing

[0057] Talc powder, brand name TYT-777A, 3000 mesh talc powder, provided by Haicheng Tianyuan.

[0058] Talc powder, brand name TY90-13-C, 1250 mesh, supplied by Guangxi Longguang.

[0059] 3) Elastomers

[0060] POE ENGAGE 7447, ethylene-butene copolymer, supplied by Dow Chemical.

[0061] POE ENGAGE 8842, ethylene-octene copolymer, supplied by Dow Chemical.

[0062] 4) Main antioxidant

[0063] SONOX 1010, a hindered phenolic antioxidant, is supplied by Mitutoyo Chemical.

[0064] 5) Co-antioxidants

[0065] SONOX 168, a phosphite antioxidant, supplied by Mitutoyo Chemical.

[0066] Examples 1-26, Comparative Examples 1-5

[0067] A polypropylene composition, the types and amounts of each component are shown in Tables 1 and 2, and the unit of amount of each component is "parts".

[0068] Application Example 1-26, Comparison with Application Example 1-5

[0069] A low-odor polypropylene, said low-odor polypropylene being prepared from the polypropylene compositions of Examples 1-26 or Comparative Examples 1-5;

[0070] The method for preparing the low-odor polypropylene includes the following steps:

[0071] Sodium bicarbonate was prepared into an aqueous solution with the concentrations shown in Tables 1 and 2. This solution was then melt-blended and extruded with polypropylene resin, filler, elastomer, primary antioxidant, and secondary antioxidant according to the specified ratio using a twin-screw extruder to obtain the low-odor polypropylene. The sodium bicarbonate aqueous solution or aqueous solution was injected at the locations shown in Tables 1 and 2. The twin-screw extruder temperatures were set as follows: Section 1: 210℃; Section 2: 250℃; Section 3: 230℃; Section 4: 210℃; Section 5: 200℃; Section 6: 190℃; Section 7: 190℃; Section 8: 190℃; Section 9: 190℃; Section 10: 190℃; Section 11: 190℃; Section 12: 190℃; Section 13: 190℃. The screw length-to-diameter ratio was 56:1, the diameter was 90.4 mm, and the rotation speed was 500 r / min.

[0072] The only difference between Comparative Example 1 and Example 4 is that the polypropylene composition does not contain sodium bicarbonate, and the sodium bicarbonate solution is replaced with an equal mass of water.

[0073] The following tests were conducted on the low-odor polypropylene obtained in Application Example 1-5, corresponding to test case 1-26:

[0074] 1) Odor test

[0075] According to the Volkswagen PV3900 standard, 20g of product is weighed and sealed in a 1-liter glass container with an odor-neutralizing seal and lid. The container is then placed in a heated chamber with circulating air at (80±2)℃ for 2 hours±10 minutes. After removal, it is cooled to the experimental temperature of (60±5)℃ before testing. After testing by three evaluators, the container is returned to the (80±2)℃ environment for 30 minutes, and then tested by another evaluator. The testing process must be completed by at least three evaluators. If the scores differ by ≥2, a retest by at least five evaluators is required.

[0076] 2) Gloss characterization

[0077] According to GB / 8807-1988 standard, the samples were injection molded into 100*100*2mm flat plates. The surface of the specimens was ensured to be smooth and flat, free from dirt, scratches, and other defects. After standard calibration of the gloss meter using a reference plate, the gloss was measured on the specimens at an incident angle of 60 degrees. At least three specimens were used in each group, and the average value was taken. To ensure test stability, the surface of the mold used to prepare the test specimens should be polished periodically with 1000-grit sandpaper. The test results are summarized in Tables 1 and 2.

[0078] Table 1

[0079]

[0080]

[0081]

[0082] Table 2

[0083]

[0084] The test results show that the polypropylene composition provided by this invention uses a specific ratio of polypropylene resin, filler, elastomer and sodium bicarbonate. By taking advantage of the characteristic of sodium bicarbonate to release carbon dioxide when heated, carbon dioxide is introduced into the material. Using carbon dioxide as the main stripping agent, the stripping and volatilization technology is used to remove volatiles from the polymer melt, thereby reducing the odor level of the product. The resulting low-odor polypropylene has an odor level ≤4.25 and can also effectively reduce gloss. Moreover, the method is simple, efficient, inexpensive, safe and widely applicable.

[0085] As can be seen from the comparative examples, by further adjusting the ratio of sodium bicarbonate to filler, the ratio of sodium bicarbonate to polypropylene resin, the amount of antioxidant, and the injection position of sodium bicarbonate solution, the present invention can more efficiently remove volatile odor substances and reduce the odor level of the product.

[0086] By comparing the examples and Comparative Example 1, it can be seen that the present invention uses sodium bicarbonate as a carrier to introduce carbon dioxide into the material for stripping and devolatilization, thereby producing low-odor polypropylene. However, when sodium bicarbonate is lacking, the resulting polypropylene material has a higher odor level and the parts have a higher gloss, which is difficult to meet the application requirements in automotive interiors.

[0087] As can be seen from the comparison of the examples and Comparative Examples 2-5, the present invention produces a polypropylene material with both good appearance and low odor by compounding polypropylene resin, filler, elastomer and sodium bicarbonate, and further optimizing the concentration and content of sodium bicarbonate solution, which is suitable for automotive interiors.

[0088] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A polypropylene composition, characterized in that, The polypropylene composition comprises, by weight parts, polypropylene resin 54-92 parts, filler 0.01-31 parts, elastomer 0.01-16 parts, and sodium bicarbonate 0.4-2.3 parts; The sodium bicarbonate is added in the form of sodium bicarbonate solution, and the mass concentration of sodium bicarbonate in the sodium bicarbonate solution is 2-15%; The mass ratio of the polypropylene resin to sodium bicarbonate is (50-90):1; The mass ratio of the sodium bicarbonate to the filler is 1:(4-20); The polypropylene resin has a melt index of 30-100 g / 10 min, which is measured at 230℃ under a 2.16 kg weight; The filler comprises any one or a combination of at least two of talc, mica, or wollastonite; The elastomer comprises a polyolefin elastomer; The step of preparing the low-odor polypropylene from the polypropylene composition comprises mixing the components in the polypropylene composition and extruding; The extruding is performed in a twin-screw extruder; When the twin-screw extruder comprises 10-13 screw sections, the mixing comprises injecting the sodium bicarbonate solution at the 3rd-7th, 2nd, 8th, and 10th screw sections.

2. The polypropylene composition according to claim 1, characterized in that The solvent of the sodium bicarbonate solution comprises water.

3. The polypropylene composition according to claim 1, characterized in that The polypropylene resin is a copolymerized polypropylene.

4. The polypropylene composition according to claim 3, characterized in that The copolymerized polypropylene comprises a propylene-ethylene copolymer.

5. The polypropylene composition according to claim 4, characterized in that The propylene-ethylene copolymer has a molar content of structural units based on propylene of 85-95%.

6. The polypropylene composition according to claim 1, characterized in that The filler is talc.

7. The polypropylene composition according to claim 6, characterized in that The talc has a particle size of 1000-3000 mesh.

8. The polypropylene composition according to claim 1, characterized in that The polyolefin elastomer comprises an ethylene-butene copolymer and / or an ethylene-octene copolymer.

9. The polypropylene composition according to claim 1, characterized in that The polypropylene composition further comprises, by weight parts, antioxidant 0.2-1 part.

10. The polypropylene composition according to claim 9, characterized in that The antioxidant comprises a combination of primary antioxidant and secondary antioxidant.

11. The polypropylene composition according to claim 10, characterized in that The mass ratio of the primary antioxidant to the secondary antioxidant is 1:(0.8-1.2).

12. The polypropylene composition according to claim 10, characterized in that The primary antioxidant comprises hindered phenolic antioxidant.

13. The polypropylene composition according to claim 12, characterized in that The hindered phenolic antioxidant comprises any one or a combination of at least two of antioxidant 1010, antioxidant 1076, antioxidant 330, or antioxidant 1790.

14. The polypropylene composition according to claim 10, characterized in that The secondary antioxidant comprises phosphite antioxidant.

15. The polypropylene composition according to claim 14, characterized in that The phosphite antioxidant comprises antioxidant 168 and / or antioxidant 627A.

16. A low odor polypropylene characterized in that, The low-odor polypropylene is prepared from the polypropylene composition according to any one of claims 1-15.

17. A process for the production of low odor polypropylene as claimed in claim 16, wherein the process is characterized by, The preparation method comprises the following steps: dissolving sodium bicarbonate in water to obtain a sodium bicarbonate solution; mixing the above sodium bicarbonate solution with polypropylene resin, filler, elastomer, optional primary antioxidant, and optional secondary antioxidant, and extruding to obtain the low-odor polypropylene; The extruding is performed in a twin-screw extruder; When the twin-screw extruder comprises 10-13 screw sections, the mixing comprises injecting the sodium bicarbonate solution at the 3rd-7th, 2nd, 8th, and 10th screw sections.

18. The method of claim 17, wherein, The mass concentration of sodium bicarbonate in the sodium bicarbonate solution is 2-15%.

19. The method of claim 18, wherein, The mass concentration of sodium bicarbonate in the sodium bicarbonate solution is 8-12%.

20. The method of claim 17, wherein, The temperature of the extruding is 190-250℃.

21. Use of the polypropylene composition according to any one of claims 1-15 or the low-odor polypropylene according to claim 16 in automotive interior.

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