Asphalt-resistant polypropylene composition, process for its preparation and use

Abstract

The application belongs to the technical field of high polymer materials, and discloses a kind of asphalt-resistant polypropylene composition and its preparation method and application.The polypropylene composition includes polypropylene resin, HDPE, amide lubricant, nucleating agent, toughening agent and filler, wherein the isotacticity of the polypropylene resin is greater than or equal to 98%, and the nucleating agent is at least one of carboxylic acid metal salt or organic phosphoric acid metal salt; the polypropylene composition provided by the application is modified by adding HDPE, amide lubricant and specific types of nucleating agent in polypropylene with specific isotacticity, and the obtained polypropylene composition not only maintains good mechanical properties, but also has the advantage of asphalt resistance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to an asphalt-resistant polypropylene composition, its preparation method, and its application. Background Technology

[0002] Polypropylene (PP) possesses advantages such as low density, ease of processing, and excellent mechanical properties, and has been widely used in the automotive, home appliance, and machinery industries. In the automotive industry, PP is mainly used in interior and exterior parts, such as bumpers, underbody protection panels, mudguards, spoilers, and wheel arches. However, when used as paintless exterior parts, it is susceptible to scratches and contamination, with asphalt tar being the most difficult to clean. Even after cleaning, it can significantly alter or damage the appearance of the parts. Therefore, improving the asphalt resistance of PP through formulation design is a crucial issue.

[0003] Existing technologies often improve asphalt resistance through coatings. For example, to improve the asphalt resistance of paint, CN102964950A discloses a method for preparing an asphalt-resistant coating. This method focuses on increasing the crosslinking density and reducing surface tension of the coating to obtain an asphalt-resistant coating, which, when applied to automotive substrates, can impart asphalt resistance to the substrate. However, for uncoated modified polypropylene materials, achieving both good mechanical properties and asphalt resistance remains a pressing technical problem to be solved. Summary of the Invention

[0004] To address the technical problem that existing polypropylene materials cannot simultaneously possess good mechanical properties and asphalt resistance, this invention provides an asphalt-resistant polypropylene composition. The asphalt-resistant polypropylene composition provided by this invention is obtained by comprehensively modifying a polypropylene matrix material of a specific isotacticity by adding HDPE, amide lubricants, and specific types of nucleating agents. This results in a polypropylene composite material that maintains both good mechanical properties and excellent asphalt resistance.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned asphalt-resistant polypropylene composition.

[0006] Another object of the present invention is to provide the application of the above-mentioned asphalt-resistant polypropylene composition in the preparation of automotive exterior parts.

[0007] Another object of the present invention is to provide an automotive exterior part prepared from the above-described polypropylene composition.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] A bitumen-resistant polypropylene composition comprising the following components in parts by weight: 49-76 parts polypropylene resin, 2-10 parts HDPE, 0.3-0.6 parts amide lubricant, 0.1-0.5 parts nucleating agent, 0-20 parts toughening agent, and 0-40 parts filler;

[0010] Wherein, the isotacticity of the polypropylene resin is ≥98%, and the nucleating agent is selected from at least one of carboxylic acid metal salts or organophosphate metal salts.

[0011] HDPE possesses high crystallinity, high density, and a dense surface. Nucleating agents such as carboxylic acid metal salts and phosphate metal salts can accelerate the crystallization rate and increase the crystal density. Adding HDPE and these nucleating agents promotes increased crystallinity and surface density in polypropylene, effectively preventing small molecules such as alkanes, aromatic hydrocarbons, and sulfides present in asphalt from entering the material's interior. During the crystallization process of HDPE and polypropylene, amide lubricants gradually precipitate to the surface, forming a protective film that acts as a barrier against small molecules in the asphalt.

[0012] Preferably, the isotacticity of the polypropylene resin can be 98%, 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, or 99%.

[0013] The inventors discovered that the higher the isotacticity of polypropylene, the better its asphalt resistance. In this invention, polypropylene with an isotacticity ≥ 98% was selected to obtain a composition with good asphalt resistance.

[0014] Specifically, the polypropylene resin accounts for no less than 56% of the mass percentage of the polypropylene composition.

[0015] Preferably, the melt flow rate of the polypropylene resin at 230°C and 2.16 kg load is 3–80 g / 10 min, more preferably 10–60 g / 10 min. Controlling the melt flow rate of the polypropylene resin within this range better balances the asphalt resistance and molding performance of the polypropylene composition.

[0016] Preferably, in order to further improve the bitumen resistance of the polypropylene composition, the melt flow rate of the HDPE at 190°C and 2.16 kg load is 0.1 to 16 g / 10 min, more preferably 0.1 to 10 g / 10 min.

[0017] If the melt flow rate of HDPE is too high, it indicates that its molecular weight is small, making it easy to precipitate, which is detrimental to its asphalt resistance and affects the notched impact strength of the simply supported beam. If it is too low, it is not conducive to molding and production.

[0018] Preferably, the HDPE has a melting point of 135–155°C and a density of 0.955–0.960 g / cm³. 3 .

[0019] Preferably, the amide lubricant is selected from at least one of erucamide, stearyl erucamide, oleamide, and docosyl fatty amide.

[0020] Specifically, the carboxylic acid metal salt is selected from at least one of sodium benzoate, potassium benzoate, or sodium p-toluenesulfonate; the organophosphate metal salt is selected from at least one of sodium 2,2'-methylenebis(2,4-di-tert-butylphenoxy)phosphate, basic aluminum 2,2'-methylenebis(4,6-di-tert-butylphenoxy)phosphate, or sodium p-tert-butylphenoxyphosphate.

[0021] Preferably, the toughening agent is selected from at least one of ethylene-octene copolymer or ethylene-butene copolymer.

[0022] Preferably, the filler is selected from at least one of talc, whiskers, or mica. More preferably, the average particle size of the filler is 2500-3500 mesh.

[0023] Preferably, the asphalt-resistant polypropylene composition further includes 0.4 to 1.6 parts of other additives.

[0024] More preferably, the other additives are selected from at least one of antioxidants, light stabilizers, and white mineral oil.

[0025] More preferably, the antioxidant is 0.1 to 0.6 parts, the light stabilizer is 0.1 to 0.5 parts, and the white mineral oil is 0.2 to 0.5 parts.

[0026] More preferably, the antioxidant is a compound antioxidant composed of hindered phenolic antioxidants and phosphite antioxidants, more preferably a compound antioxidant composed of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is preferably 1 to 2:1.

[0027] More preferably, the light stabilizer is a hindered amine light stabilizer, specifically at least one of UV3808PP5, LA-402AF or UV770, more preferably a hindered amine light stabilizer with a relative molecular weight ≥800, and its melting point is preferably 120-140°C.

[0028] Preferably, the polypropylene composition further includes a lubricant, preferably a metal stearate salt, specifically at least one of calcium stearate, zinc stearate, or magnesium stearate, preferably 0.2 to 1 part.

[0029] The method for preparing the above-mentioned bitumen-resistant polypropylene composition includes the following steps:

[0030] S1. Mix polypropylene resin, HDPE, amide lubricant, nucleating agent, toughening agent, filler and other additives evenly to obtain a mixture;

[0031] S2. The mixture is melt-blended, extruded and granulated to obtain the polypropylene composition.

[0032] Preferably, the melt mixing is carried out in a twin-screw extruder.

[0033] Preferably, the mixing temperature is 170–220°C and the screw speed is 350–450 rpm.

[0034] The application of the above-mentioned asphalt-resistant polypropylene composition in the preparation of automotive exterior parts is also within the scope of protection of this invention.

[0035] The application of the above-mentioned asphalt-resistant polypropylene composition in the preparation of asphalt-resistant automotive exterior parts is also within the scope of protection of this invention.

[0036] An automotive exterior part is prepared from the above-mentioned polypropylene composition.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The asphalt-resistant polypropylene composition provided by this invention is obtained by comprehensively modifying polypropylene resin by adding nucleating agents such as HDPE, amide lubricants, phosphate metal salts or carboxylic acid metal salts. The resulting polypropylene composition has both good asphalt resistance and mechanical properties, and can be used to prepare asphalt-resistant and easy-to-clean exterior parts, which can be widely used in the preparation of automotive exterior parts. Detailed Implementation

[0039] The present invention is further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from the conventional market. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are within the scope of protection claimed by the present invention.

[0040] The reagents used in the various embodiments and comparative examples of this invention are described below:

[0041] Polypropylene 1: Grade PP 225 (STL), manufacturer: Satellite Petrochemical, according to GB / T 2412-2008 standard, isotacticity is 98.8; according to ISO1133-2022 standard, melt mass flow rate at 230℃ and 2.16kg is 29g / 10min.

[0042] Polypropylene 2: Grade CS820, manufacturer: Sinopec, according to GB / T 2412-2008 standard, isotacticity is 97.5; according to ISO1133-2022 standard, melt mass flow rate at 230℃ and 2.16kg is 24g / 10min.

[0043] Polypropylene 3: Grade CJS700H, manufacturer: Sinopec, according to GB / T 2412-2008 standard, isotacticity is 98.3; according to ISO1133-2022 standard, melt flow rate at 230℃ and 2.16kg is 10g / 10min.

[0044] Polypropylene 4: Grade P901, manufacturer SCG, isotacticity of 98.5 according to GB / T 2412-2008 standard; melt flow rate of 60g / 10min at 230℃ and 2.16kg according to ISO1133-2022 standard.

[0045] Polypropylene 5: Grade P401S, manufacturer SCG, isotacticity of 98.1 according to GB / T 2412-2008 standard; melt flow rate of 3g / 10min at 230℃ and 2.16kg according to ISO1133-2022 standard.

[0046] Polypropylene 6: Grade K7100, manufactured by Sinopec, according to GB / T 2412-2008 standard, isotacticity is 98.1; according to ISO1133-2022 standard, melt flow rate at 230℃ and 2.16kg is 80g / 10min.

[0047] HDPE 1: Grade 3300J, manufactured by Sinopec, according to ISO1133-2022 standard, melt flow rate at 190℃ and 2.16kg is 2.6g / 10min;

[0048] HDPE 2: Grade T60-800, manufactured by Sinopec, according to ISO1133-2022 standard, melt flow rate at 190℃ and 2.16kg is 8.5g / 10min;

[0049] HDPE 3: Grade 5200B, manufactured by Sinopec, according to ISO1133-2022 standard, melt flow rate at 190℃ and 2.16kg is 0.3g / 10min;

[0050] HDPE 4: Grade DMDA8916, manufactured by Sinopec, according to ISO1133-2022 standard, melt flow rate at 190℃ and 2.16kg is 16g / 10min;

[0051] HDPE 5: Grade 6100M, manufactured by Sinopec, according to ISO1133-2022 standard, melt flow rate at 190℃ and 2.16kg is 0.15g / 10min;

[0052] Amide lubricant 1: Oleamide, commercially available;

[0053] Amide lubricant 2: Erucamide, commercially available;

[0054] Amide lubricant 3: Stearyl erucamide, commercially available;

[0055] Non-amide lubricant 1: Glyceryl monostearate, commercially available;

[0056] Non-amide lubricant 2: Glyceryl fatty acid ester, commercially available;

[0057] Nucleating agent 1: Carboxylic acid metal salt, sodium benzoate, brand name NAR-6, manufacturer Chenghe Technology;

[0058] Nucleating agent 2: Phosphate metal salt, sodium 2,2'-methylene bis(4,6-di-tert-butylphenyl) phosphate, brand name NA-11, manufacturer: Adico;

[0059] Nucleating agent 3: Sorbitol derivative, 1,3-2,4-di(3,4-dimethylbenzyl)-D-sorbitol, brand name Millad 3988, manufacturer Milliken;

[0060] Nucleating agent 4: Sorbitol acetal, 1,3-2,4-dibenzylsorbitol, brand name Millad 3905, manufacturer Milliken;

[0061] Toughening agent 1: Ethylene-octene copolymer, grade POE8100, manufacturer: DOW, USA;

[0062] Toughening agent 2: Ethylene-butene copolymer, grade POE7467, manufacturer: DOW, USA;

[0063] Filler 1: Talc powder, grade AH-1250N6, manufacturer: Liaoning Aihai;

[0064] Packing material 2: Mica, grade C-50, manufactured by Lingshou County Huajing Mica Co., Ltd.

[0065] Filler 3: Fiberglass, grade ESC3F-03-508A, manufacturer: Jushi Fiberglass;

[0066] Antioxidant 1: Hindered phenolic antioxidant, Antioxidant 1010, commercially available;

[0067] Antioxidant 2: Phosphite antioxidant, Antioxidant 168, commercially available;

[0068] Light stabilizer: Hindered amine light stabilizer, brand name LA-402AF, manufacturer: Adico;

[0069] White mineral oil: No. 10 white mineral oil, Shanghai Daliang Chemical Co., Ltd.

[0070] Lubricant: BS-2818, zinc stearate, Zhongshan Huamingtai.

[0071] The polypropylene compositions of the embodiments and comparative examples of the present invention were prepared by the following process:

[0072] S1. Mix the components in the formulations of each embodiment and comparative example evenly to obtain a mixture;

[0073] S2. Add the mixture to a twin-screw extruder and melt-mix it. Set the extruder temperature to 170℃, 180℃, 190℃, 200℃, 210℃, and 220℃, the die temperature to 210℃, the feed rate to 30 kg, the vacuum degree to -0.08, and the screw speed to 380 rpm. Extrude and granulate to obtain the polypropylene composition.

[0074] The performance testing methods and standards for the polypropylene compositions of the various embodiments and comparative examples of the present invention are as follows:

[0075] Determination of asphalt resistance: Refer to Q / BYDQ-A1901.402.2-2023. Apply 90# asphalt to the test piece, leave it at room temperature for 30 minutes, and then clean it with gasoline. Judgment method: After the test, there should be no twisting deformation, delamination, melting, cracking, whitening, discoloration, or dirt. A discoloration grade of 4-5 is acceptable, and a grade of 1-3 is unacceptable.

[0076] Determination of impact strength of simply supported beam: Referring to ISO 179-1:2010, ISO 179-1eA type notch was made on the test piece, and the test was carried out at 23℃ with a pendulum energy of 2J.

[0077] Heat distortion temperature determination: According to ISO 75-1:2013, it was measured at a heating rate of 10℃ / min under a load of 0.45MPa.

[0078] Examples 1-23

[0079] This embodiment provides a series of polypropylene compositions, the weight parts of each component in the formulation and their bitumen resistance properties are shown in Tables 1-2.

[0080] Table 1. Formulations (parts) for Examples 1-13

[0081]

[0082]

[0083] Table 2. Formulas (parts) for Examples 14-23

[0084]

[0085]

[0086] Comparative Examples 1-16

[0087] This comparative example provides a series of polypropylene compositions, the weight parts of each component in the formulation and their bitumen resistance properties are shown in Table 3.

[0088] Table 3: Formulations (per serving) for Comparative Examples 1–16

[0089]

[0090]

[0091] As can be seen from Tables 1-2, the polypropylene compositions prepared in Examples 1-23 of this invention, after being coated with asphalt and cleaned, showed no changes in appearance such as distortion, delamination, melting, cracking, whitening, discoloration, or dirt, with a discoloration level of 4-5, and a strength greater than 8.5 KJ·m -2 The simply supported beam impact strength and heat distortion temperature greater than 105°C, along with the imparting of asphalt resistance without a significant reduction in mechanical properties, demonstrate that the polypropylene composition of this invention possesses both excellent asphalt resistance and mechanical properties. In Comparative Example 1, polypropylene with an isotacticity lower than 98% was used as the matrix, resulting in microcracks on the surface of the test piece and a low discoloration grade. Comparative Examples 6-7 were modified with non-amide lubricants, resulting in microcracks on the surface of the test piece and a low discoloration grade; compared to Example 1, both the simply supported beam impact strength and heat distortion temperature were reduced. Comparative Examples 10-11 were modified with non-carboxylic acid metal salts or non-phosphate metal salts as nucleating agents, resulting in expansion deformation of the test piece; compared to Example 1, the simply supported beam impact strength was reduced. In Comparative Example 12, the amount of HDPE added was 0, and the test piece… Expansion and deformation phenomena occurred; in Comparative Example 3, the amount of amide lubricant added was 0, and the test piece showed surface whitening and poor asphalt resistance; in Comparative Example 14, the amount of nucleating agent added was 0, and the test piece showed expansion and deformation phenomena. Compared with Example 1, the impact strength and heat distortion temperature of the simply supported beam were reduced; in other comparative examples, the weight parts of each component were not within the range set by this invention, and the test piece surface showed phenomena such as whitening, deformation, cracks or delamination. The impact strength and / or heat distortion temperature of the simply supported beam were generally reduced, and it was impossible to simultaneously achieve good mechanical properties and asphalt resistance.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A bituminous resistant polypropylene composition comprising the following components in parts by weight: 50-75 parts polypropylene resin, 2-10 parts HDPE, 0.3-0.6 parts amide lubricant, 0.1-0.5 parts nucleating agent, 0-20 parts toughening agent, and 0-40 parts filler; in, The isotacticity of the polypropylene resin is ≥98%, and the nucleating agent is at least one of a carboxylic acid metal salt or an organophosphate metal salt. The carboxylic acid metal salt is selected from at least one of sodium benzoate, potassium benzoate, or sodium p-toluenesulfonate. The organophosphate metal salt is selected from at least one of 2,2'-methylenebis(2,4-di-tert-butylphenoxy)phosphate, 2,2'-methylenebis(4,6-di-tert-butylphenoxy)phosphate aluminum basic salt, or p-tert-butylphenoxy phosphate.

2. The polypropylene composition according to claim 1, characterized in that, The melt flow rate of the polypropylene resin at 230℃ and 2.16kg load is 10~60g / 10min.

3. The polypropylene composition according to claim 1, characterized in that, The melt flow rate of the HDPE at 190℃ and 2.16kg load is 0.2~10g / 10min.

4. The polypropylene composition according to claim 1, characterized in that, The amide lubricant is selected from at least one of erucamide, stearyl erucamide, oleamide, or docosyl fatty amide.

5. The polypropylene composition according to claim 1, characterized in that, The asphalt-resistant polypropylene composition also includes 0.4 to 1.6 parts of other additives.

6. A method for preparing the polypropylene composition according to any one of claims 1 to 5, comprising the following steps: S1. Mix polypropylene resin, HDPE, amide lubricant, nucleating agent, toughening agent, filler and other additives evenly to obtain a mixture; S2. The mixture is melt-blended, extruded and granulated to obtain the polypropylene composition.

7. The use of the polypropylene composition according to any one of claims 1 to 5 in the preparation of automotive exterior parts.

8. An automotive exterior part, prepared from the polypropylene composition according to any one of claims 1 to 5.

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