Asphalt-resistant polypropylene composition as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of high polymer materials, and discloses an asphalt-resistant polypropylene composition as well as a preparation method and application thereof. The polypropylene composition comprises polypropylene resin, HDPE, an amide lubricant, a nucleating agent, a flexibilizer and a filler, 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; according to the polypropylene composition provided by the invention, the HDPE, the amide lubricant and the specific type of nucleating agent are added into the polypropylene with specific isotacticity for comprehensive modification, so that the obtained polypropylene composition not only keeps good mechanical properties, but also has the advantage of asphalt resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to an asphalt-resistant polypropylene composition and a preparation method and application thereof. Background Art

[0002] Polypropylene (PP) has the advantages of low density, easy processing, and excellent mechanical properties. It has been widely used in the automotive industry, home appliances, and machinery. For the automotive industry, polypropylene is mainly used in automotive interior and exterior parts, such as bumpers, underbody guards, fenders, deflectors, wheel arches, etc. However, when it is used as a spray-free exterior part of a car, it is easily scratched and contaminated. Among them, the pollution from road asphalt is the most difficult to clean. Even after cleaning, the appearance of the parts will be significantly changed or damaged. How to improve the asphalt resistance of polypropylene from the perspective of formula design is a problem worthy of attention.

[0003] The existing technology often improves asphalt resistance through coating. For example, in order to improve the asphalt resistance of paint, CN102964950A discloses a method for preparing asphalt-resistant coatings. From the perspective of improving the cross-linking density of the coating and reducing the surface tension, a coating with asphalt resistance is prepared. Applying it to the automotive substrate can make the substrate have asphalt resistance. For uncoated polypropylene modified materials, how to have both good mechanical properties and asphalt resistance is still a technical problem that needs to be solved urgently. Summary of the invention

[0004] In order to solve the technical problem that polypropylene materials in the prior art cannot have both good mechanical properties and asphalt resistance, the present invention provides an asphalt-resistant polypropylene composition. The asphalt-resistant polypropylene composition provided by the present invention is comprehensively modified by adding HDPE, amide lubricants and specific types of nucleating agents to a specific isotactic polypropylene matrix material, and the obtained polypropylene composite material not only maintains good mechanical properties, but also has good 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 use of the 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 polypropylene composition.

[0008] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0009] An asphalt-resistant polypropylene composition comprises the following components in parts by weight: 49-76 parts of polypropylene resin, 2-10 parts of HDPE, 0.3-0.6 parts of amide lubricant, 0.1-0.5 parts of nucleating agent, 0-20 parts of toughening agent, and 0-40 parts of 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 organic phosphate metal salts.

[0011] HDPE has 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 the above nucleating agents can promote polypropylene to improve crystallinity and surface density, which is beneficial to prevent small molecules such as alkanes, aromatic hydrocarbons, and sulfides in asphalt from entering the material from the outside. During the crystallization process of HDPE and polypropylene, amide lubricants will gradually precipitate on the surface, thereby forming a protective film that can block small molecules in asphalt.

[0012] Preferably, the isotacticity of the polypropylene resin may 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 have found that the higher the isotacticity of polypropylene, the better the asphalt resistance. The present invention uses polypropylene with an isotacticity of ≥98% to obtain a composition with good asphalt resistance.

[0014] Specifically, the mass percentage of the polypropylene resin in the polypropylene composition is not less than 56%.

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

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

[0017] If the melt mass flow rate of HDPE is too large, it means that its molecular weight is small and it is easy to precipitate, which is not good for asphalt resistance and affects the simply supported beam notched impact strength of the material. If it is too low, it is not conducive to molding production.

[0018] Preferably, the melting point of the HDPE is 135-155°C and the density is 0.955-0.960 g / cm 3 .

[0019] Preferably, the amide lubricant is selected from at least one of erucamide, stearyl erucamide, oleamide, and behenyl 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 organic phosphate metal salt is selected from at least one of 2,2'-methylenebis(2.4-di-tert-butylphenoxy) sodium phosphate, 2.2'-methylenebis(4.6-di-tert-butylphenoxy)aluminum phosphate basic salt or sodium p-tert-butylphenoxy phosphate.

[0021] Preferably, the toughening agent is selected from at least one of ethylene-octene copolymer and 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 comprises 0.4 to 1.6 parts of other additives.

[0024] More preferably, the other auxiliary agent is selected from at least one of an antioxidant, a light stabilizer 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] Further preferably, the antioxidant is a compound antioxidant composed of a hindered phenol antioxidant and a phosphite antioxidant, 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] Further 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 a melting point of 120-140°C.

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

[0029] The method for preparing the asphalt-resistant polypropylene composition comprises the following steps:

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

[0031] S2. The mixture is melt-kneaded and extruded into pellets to obtain the polypropylene composition.

[0032] Preferably, the melt-kneading 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 use of the above-mentioned asphalt-resistant polypropylene composition in the preparation of automobile exterior parts is also within the protection scope of the present invention.

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

[0036] An automobile exterior part is prepared from the polypropylene composition.

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

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

[0039] The present invention is further described below in conjunction with examples. These examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually carried out according to conventional conditions in the art or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope of protection claimed by the present invention.

[0040] Some of the reagents selected in the embodiments and comparative examples of the present invention are described as follows:

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

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

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

[0044] Polypropylene 4: brand P901, manufacturer SCG, according to GB / T 2412-2008 standard, isotacticity is 98.5; according to ISO1133-2022 standard, the melt mass flow rate at 230°C and 2.16kg is 60g / 10min;

[0045] Polypropylene 5: brand P401S, manufacturer SCG, according to GB / T 2412-2008 standard, isotacticity is 98.1; according to ISO1133-2022 standard, the melt mass flow rate at 230°C and 2.16kg is 3g / 10min;

[0046] Polypropylene 6: Brand K7100, manufacturer Sinopec, according to GB / T 2412-2008 standard, isotacticity is 98.1; according to ISO1133-2022 standard, the melt mass flow rate at 230°C and 2.16kg is 80g / 10min;

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

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

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

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

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

[0052] Amide lubricant 1: oleic acid amide, commercially available;

[0053] Amide lubricant 2: erucic acid amide, commercially available;

[0054] Amide lubricant 3: stearyl erucic acid amide, commercially available;

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

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

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

[0058] Nucleating agent 2: phosphoric acid metal salt, sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl) phosphate, brand NA-11, manufacturer Aidico;

[0059] Nucleating agent 3: sorbitol, 1,3-2,4-di(3,4-dimethylbenzylidene)-D-sorbitol, brand name Millad3988, manufacturer Milliken;

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

[0061] Toughener 1: ethylene-octene copolymer, brand POE8100, manufacturer: DOW, USA;

[0062] Toughener 2: ethylene-butene copolymer, brand POE7467, manufacturer: DOW, USA;

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

[0064] Filler 2: mica, brand C-50, manufacturer Lingshou County Huajing Mica Co., Ltd.

[0065] Filler 3: glass fiber, brand ESC3F-03-508A, manufacturer Jushi Glass Fiber;

[0066] Antioxidant 1: hindered phenol antioxidant, antioxidant 1010, commercially available;

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

[0068] Light stabilizer: hindered amine light stabilizer, brand LA-402AF, manufacturer Aidico;

[0069] White mineral oil: 10# white mineral oil, Shanghai Daliang Chemical;

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

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

[0072] S1. The components of the formula of each embodiment and comparative example are mixed uniformly to obtain a mixture;

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

[0074] The performance test methods and standards of the polypropylene compositions of the 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 on the test piece, place it at room temperature for 30 minutes, and then clean it with gasoline. Judgment method: After the test, there is no distortion, delamination, melting, cracking, whitening, discoloration, dirtiness, etc.; discoloration level 4-5 is qualified, 1-3 is unqualified.

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

[0077] Determination of heat distortion temperature: refer to ISO 75-1:2013, measured at a heating rate of 10°C / min under a load of 0.45 MPa.

[0078] Examples 1 to 23

[0079] This embodiment provides a series of polypropylene compositions, the weight proportions of the components in the formulations and their asphalt resistance properties are shown in Table 1-2.

[0080] Table 1 Examples 1 to 13 formulations (parts)

[0081]

[0082]

[0083] Table 2 Examples 14 to 23 formulations (parts)

[0084]

[0085]

[0086] Comparative Examples 1 to 16

[0087] This comparative example provides a series of polypropylene compositions, the weight parts of each component in the formula and the asphalt resistance performance thereof are shown in Table 3.

[0088] Table 3 Formulas of Comparative Examples 1 to 16 (parts)

[0089]

[0090]

[0091] It can be seen from Table 1-2 that the polypropylene compositions prepared in Examples 1 to 23 of the present invention have no appearance changes such as distortion, delamination, melting, cracking, whitening, discoloration, dirtiness, etc. after being smeared and cleaned with asphalt, and the discoloration level is 4-5, and the thermal conductivity is greater than 8.5 KJ·m -2 The simply supported beam impact strength and heat deformation temperature greater than 105°C, the imparting of asphalt resistance will not lead to a significant decrease in mechanical properties. The polypropylene composition of the present invention has both good asphalt resistance and mechanical properties. In Comparative Example 1, polypropylene with an isotacticity of less than 98% is used as the matrix, microcracks appear on the surface of the test piece, and the discoloration level is low; Comparative Examples 6-7 are modified with non-amide lubricants, microcracks appear on the surface of the test piece, and the discoloration level is low. Compared with Example 1, the simply supported beam impact strength and heat deformation temperature are reduced; Comparative Examples 10-11 are modified with non-carboxylic acid metal salts or non-phosphate metal salts as nucleating agents, and the test piece shows expansion and deformation. Compared with Example 1, the simply supported beam impact strength is reduced; Comparative Example 12 adds 0 HDPE, then the test piece Swelling and deformation 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, and compared with Example 1, the simply supported beam impact strength and heat deformation temperature were reduced; in other comparative examples, the weight of each component was not within the range set by the present invention, and the surface of the test piece showed whitening, deformation, cracks or stratification, and the simply supported beam impact strength and / or heat deformation temperature were generally reduced, and it was impossible to take into account both good mechanical properties and asphalt resistance.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. An asphalt-resistant polypropylene composition, comprising the following components in parts by weight: 49-76 parts of polypropylene resin, 2-10 parts of HDPE, 0.3-0.6 parts of amide lubricant, 0.1-0.5 parts of nucleating agent, 0-20 parts of toughening agent, and 0-40 parts of 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 organic phosphate metal salt.

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

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

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 behenyl fatty amide.

5. The polypropylene composition according to claim 1, characterized in that The carboxylic acid metal salt is selected from at least one of sodium benzoate, potassium benzoate or sodium p-toluenesulfonate.

6. The polypropylene composition according to claim 1, characterized in that The organic phosphoric acid metal salt is selected from at least one of 2,2'-methylenebis(2.4-di-tert-butylphenoxy) sodium phosphate, 2.2'-methylenebis(4.6-di-tert-butylphenoxy) aluminum phosphate basic salt or sodium p-tert-butylphenoxy phosphate.

7. The polypropylene composition according to claim 1, characterized in that The asphalt-resistant polypropylene composition further comprises 0.4 to 1.6 parts of other additives.

8. The method for preparing the polypropylene composition according to any one of claims 1 to 7, comprising the following steps: S1. The polypropylene resin, HDPE, amide lubricant, nucleating agent, toughening agent, filler and other additives are mixed to obtain a mixture; S2. The mixture is melt-kneaded and extruded into pellets to obtain the polypropylene composition.

9. Use of the polypropylene composition according to any one of claims 1 to 7 in the preparation of automobile exterior parts.

10. An automobile exterior part prepared from the polypropylene composition according to any one of claims 1 to 7.

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