Polypropylene composition as well as preparation method and application thereof

Abstract

The invention provides a polypropylene composition as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The polypropylene composition disclosed by the invention is prepared from the following components in parts by weight: 33 to 72 parts of polypropylene, 8 to 32 parts of silicon-based thermoplastic elastomer, 5 to 15 parts of alpha-polyolefin, 5 to 15 parts of porous graphene, 5 to 25 parts of silicate filler and 0.1 to 1 part of additive, wherein the alpha-polyolefin is a copolymer of ethylene, propylene and 1-butene. The silicon-based thermoplastic elastomer, the alpha-polyolefin and the porous graphene are added into the polypropylene composition, so that the low-temperature toughness of the polypropylene composition is effectively improved, and the volatile odor of the polypropylene composition is reduced.

Description

Technical Field

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

[0002] As a plastic that is easy to process, has good heat resistance, good stability and high strength, polypropylene is increasingly used in automotive interiors. However, with the increasing proportion of polypropylene used in automotive interiors, the impact of the odor volatilized by polypropylene on the air quality inside the vehicle is becoming more and more obvious. The odor inside the vehicle directly affects the quality of the vehicle, and affects human health and the ecological environment. In order to ensure the safety inside the vehicle, the "Guidelines for the Evaluation of the Air Quality Inside Passenger Cars" has become a mandatory standard, which has strict requirements for the air quality inside the vehicle. Since the amount of polypropylene used in automotive interiors is large and the varieties are numerous, it is particularly important to develop low-odor polypropylene suitable for automotive interiors.

[0003] In order to reduce the odor of polypropylene, currently, mainly porous materials with adsorption functions are added to polypropylene. Adsorbents such as activated carbon, silica gel, metal oxides, attapulgite, and molecular sieves have emerged. When the above adsorption systems are distributed in the resin matrix in a certain form, they can all adsorb the odor or volatile small molecules generated by the resin. However, the effect of porous materials in adsorbing the volatile components of the volatilization aids is limited, and when too much porous adsorbent is used, the oil absorption value of the porous material is relatively high, which will cause the lubrication aids to be adsorbed, thereby reducing the lubrication and slip effects and resulting in a decline in the mechanical properties of the polypropylene material.

[0004] Therefore, on the basis of ensuring the performance of the polypropylene material, how to reduce the volatile odor of polypropylene is an urgent problem to be solved at present. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a polypropylene composition, a preparation method thereof and an application thereof.

[0006] To achieve the above purpose, the technical solutions adopted by the present invention are as follows: In the first aspect, a polypropylene composition is provided, which comprises the following components in parts by weight: 33-72 parts of polypropylene, 8-32 parts of a silicone-based thermoplastic elastomer, 5-15 parts of an α-olefin, 5-15 parts of porous graphene, 5-25 parts of a silicate filler, and 0.1-1 part of an additive; wherein the α-olefin is a copolymer of ethylene, propylene and 1-butene.

[0007] In some embodiments, the Shore hardness of the silicone-based thermoplastic elastomer is 40-70A.

[0008] In some embodiments, the tensile strength of the α-olefin is 1.5-5 MPa.

[0009] In some embodiments, the silicate filler is at least one of talcum powder, wollastonite, kaolin, and mica.

[0010] In some embodiments, the auxiliary agent is at least one of a lubricant, an antioxidant, and a light stabilizer.

[0011] In some embodiments, the lubricant is at least one of a low molecular weight lipid lubricant, a metal soap lubricant, a stearic acid composite ester lubricant, and an amide lubricant; In some embodiments, the antioxidant is at least one of a phenolic antioxidant, a phosphite antioxidant, and a divalent sulfur antioxidant; In some embodiments, the light stabilizer is a hindered amine light stabilizer.

[0012] In some embodiments, the melt mass flow rate of the polypropylene at 230 °C under a load of 2.16 kg is 1 - 100 g / 10min.

[0013] In a second aspect, a method for preparing the polypropylene composition is provided, including the following steps: After mixing each component evenly, the obtained premix is added to a screw extruder, melted and extruded into pellets to obtain the polypropylene composition.

[0014] In some embodiments, the temperature of the melt extrusion and pelletizing is 200 - 220 °C.

[0015] In a third aspect, an application of the polypropylene composition in preparing automotive interior parts is provided.

[0016] In a fourth aspect, an automotive interior is provided, and the automotive interior includes the polypropylene composition.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: In the polypropylene composition of the present invention, a silicone-based thermoplastic elastomer, an α-olefin, and porous graphene are added, effectively improving the low-temperature toughness of the polypropylene composition and reducing the volatile odor of the polypropylene composition. Among them, the silicone-based thermoplastic elastomer uniformly disperses vulcanized silicone rubber particles in a thermoplastic resin to form a special sea-island structure, with the thermoplastic resin as the continuous phase and the silicone rubber as the dispersed phase. The porous structure formed by the silicone rubber particles can adsorb volatile organic compounds (VOCs), and at the same time improve the low-temperature toughness of the polypropylene composition; α-olefin is polymerized from three monomers of ethylene, propylene, and 1-butene, and α-olefin can further enhance the compatibility and dispersion effect of the silicone-based thermoplastic elastomer and polypropylene, improving the low-temperature toughness of the polypropylene composition; the microporous structure of the porous graphene can further adsorb volatile organic compounds. Specific Embodiments

[0018] For the convenience of understanding the present invention, the present invention will be described more comprehensively below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0019] As used herein, the terms: "prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing" or any other variation thereof used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or apparatus comprising the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article or apparatus.

[0020] The connecting phrase "consisting of" excludes any unstated element, step or component. If used in a claim, this phrase will render the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the claim body rather than immediately following the subject, it only limits the elements described in that clause; other elements are not excluded from the claim as a whole.

[0021] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, it should be understood that all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value are specifically disclosed, regardless of whether the ranges are separately disclosed. For example, when the range "1-5" is disclosed, the described range should be interpreted as including the ranges "1-4", "1-3", "1-2", "1-2 and 4-5", "1-3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0022] In these embodiments, unless otherwise specified, the parts and percentages are by mass.

[0023] "parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g, etc. Suppose we say that the mass part of component A is a parts and the mass part of component B is b parts, then it represents the mass ratio a:b of component A and component B. Or, it represents that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the mass percentage content, the sum of the mass parts of all components is not limited to 100 parts.

[0024] "And / or" is used to indicate that one or both of the described situations may occur. For example, A and / or B includes (A and B) and (A or B).

[0025] To solve the problems of low odor and poor low-temperature toughness of polypropylene materials in the prior art.

[0026] In the first aspect of the present invention, a polypropylene composition is provided, comprising the following components in parts by weight: 33 - 72 parts of polypropylene, 8 - 32 parts of a silicon-based thermoplastic elastomer, 5 - 15 parts of an α-olefin, 5 - 15 parts of porous graphene, 5 - 25 parts of a silicate filler, and 0.1 - 1 part of an additive; wherein the α-olefin is a copolymer of ethylene, propylene, and 1-butene.

[0027] In different embodiments, the parts by weight of the polypropylene may be, but are not limited to, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts; In different embodiments, the parts by weight of the silicon-based thermoplastic elastomer may be, but are not limited to, 10 parts, 12 parts, 15 parts, 17 parts, 20 parts, 23 parts, 25 parts, 28 parts, 30 parts; In different embodiments, the parts by weight of the α-olefin may be, but are not limited to, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts; In different embodiments, the parts by weight of the porous graphene may be, but are not limited to, 5 parts, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 15 parts; In different embodiments, the parts by weight of the silicate filler may be, but are not limited to, 5 parts, 7 parts, 10 parts, 13 parts, 15 parts, 17 parts, 19 parts, 21 parts, 23 parts, 25 parts; In different embodiments, the parts by weight of the additive may be, but are not limited to, 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part.

[0028] Specifically, in the polypropylene composition of the present invention, the mass percentage content of polypropylene is not less than 35%.

[0029] Specifically, the polypropylene includes at least one of homopolypropylene, random copolymer polypropylene, and block copolymer polypropylene.

[0030] In the polypropylene composition of the present invention, a silicone-based thermoplastic elastomer, an α-olefin, and porous graphene are added, effectively improving the low-temperature toughness of the polypropylene composition and reducing the volatile odor of the polypropylene composition. Among them, the silicone-based thermoplastic elastomer uniformly disperses vulcanized silicone rubber particles with an average particle size of 2-3 μm in a thermoplastic resin to form a special sea-island structure. The thermoplastic resin serves as the continuous phase, and the silicone rubber serves as the dispersed phase. The porous structure formed by the silicone rubber particles can adsorb volatile organic compounds (TVOCs), and at the same time improve the low-temperature toughness of the polypropylene composition; the α-olefin is polymerized from three monomers, ethylene, propylene, and 1-butene. The α-olefin can further enhance the compatibilizing and dispersing effect between the silicone-based thermoplastic elastomer and polypropylene, and improve the low-temperature toughness of the polypropylene composition; the microporous structure of the porous graphene can further adsorb volatile organic compounds.

[0031] In the present invention, the thermoplastic resin matrix of the silicone-based thermoplastic elastomer is one of polyolefin, polyurethane, and nylon.

[0032] In some embodiments, the Shore hardness of the silicone-based thermoplastic elastomer is 40-70A, for example, it can be but not limited to 45A, 47A, 50A, 53A, 55A, 58A, 60A, 62A, 65A, 70A, and its test method is ISO 48-4:2018.

[0033] The silicone-based thermoplastic elastomer with a hardness of 40-65A can further improve the rigidity and low-temperature toughness of the polypropylene composition.

[0034] In some embodiments, the α-olefin is an amorphous α-olefin.

[0035] In some embodiments, the tensile strength of the α-olefin is 1.5-5 MPa, for example, it can be but not limited to 1.5 MPa, 1.8 MPa, 2.0 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, and its test method is ISO527-3:2018.

[0036] The α-olefin with a tensile strength of 1.5-5 MPa can further improve the low-temperature toughness of the polypropylene composition.

[0037] In order to further improve the rigidity and low-temperature toughness of the polypropylene composition, the present invention preferably uses a silane-modified α-olefin, and more preferably a silicone oxide-grafted α-olefin.

[0038] In some embodiments, the silicate filler is at least one of talc, wollastonite, kaolin, and mica.

[0039] The above-mentioned types of silicate fillers can enhance the dispersion of the silicone-based thermoplastic elastomer during the extrusion process, thereby better absorbing the broken-chain alkane molecules generated during the extrusion and injection molding processes, enabling the polypropylene composition to achieve a balance between rigidity and toughness while reducing volatile odors.

[0040] Specifically, the average particle size of the silicate filler is 1-50 μm, and its test method is HS∕T 49-2016.

[0041] In some embodiments, the auxiliary agent is at least one of a lubricant, an antioxidant, and a light stabilizer.

[0042] In some embodiments, the lubricant is at least one of a low-molecular-weight lipid lubricant, a metal soap lubricant, a stearic acid composite ester lubricant, and an amide lubricant; among them, the low-molecular-weight lipid lubricant can be selected from at least one of solid paraffin, liquid paraffin, and low-molecular-weight polyolefin wax; the metal soap lubricant can be selected from at least one of calcium stearate, magnesium stearate, zinc stearate, and barium stearate; the stearic acid composite ester lubricant can be selected from at least one of monoglyceride, ethylene glycol stearate, glycerol stearate, and pentaerythritol stearate; the amide lubricant can be selected from at least one of oleic acid amide, erucic acid amide, methylene bis-stearic acid amide, and N,N-ethylene bis-stearic acid amide.

[0043] In some embodiments, the antioxidant is at least one of a phenolic antioxidant, a phosphite antioxidant, and a divalent sulfur antioxidant; the phenolic antioxidant can be selected from at least one of antioxidant 264, antioxidant 1010, antioxidant 1076, antioxidant SP, antioxidant 2246, antioxidant CA, antioxidant 330, Irganox1890, and antioxidant 3114; the phosphite antioxidant can be selected from at least one of antioxidant TN P, antioxidant ODP, antioxidant 168, Irganox1093, and Irganox1222; the divalent sulfur antioxidant can be selected from at least one of dilauryl thiodipropionate (DLTP) and distearyl thiodipropionate (DSTP).

[0044] In some embodiments, the light stabilizer is a hindered amine light stabilizer, and the hindered amine light stabilizer can specifically be at least one of UV-3808, LA-402XP, and LA-402AF.

[0045] In some embodiments, the polypropylene has a melt mass flow rate of 1-100 g / 10 min at 230 °C under a load of 2.16 kg, and can be, for example, but not limited to, 1 g / 10 min, 10 g / 10 min, 20 g / 10 min, 30 g / 10 min, 50 g / 10 min, 70 g / 10 min, 80 g / 10 min, 90 g / 10 min, 100 g / 10 min. The test method is ISO 1133-1:2022.

[0046] In a second aspect, a method for preparing the polypropylene composition is provided, comprising the following steps: After mixing the components in proportion and uniformly, the obtained premix is added to a screw extruder, melted and extruded into pellets to obtain the polypropylene composition.

[0047] In some embodiments, the temperature of the melt extrusion and pelletizing is 200-220 °C.

[0048] In some embodiments, the screw speed of the screw extruder is 350-450 revolutions per minute.

[0049] In a third aspect, the application of the polypropylene composition in preparing automotive interior parts is provided, specifically such as interior parts like instrument panels, door panels, and pillars.

[0050] The raw materials used in the examples and comparative examples are described as follows, but are not limited to these materials: Polypropylene A: It has a melt mass flow rate of 60 g / 10 min at 230 °C under a load of 2.16 kg, PPM60RHC, Zhenhai Refining & Chemical. Polypropylene B: It has a melt mass flow rate of 100 g / 10 min at 230 °C under a load of 2.16 kg, PPBX3920, SINOPEC-KOREA Petrochemical. Polypropylene C: It has a melt mass flow rate of 1 g / 10 min at 230 °C under a load of 2.16 kg, PP 3010, Formosa Plastics. Silicone-based thermoplastic elastomer A: Silicone rubber particles are dispersed in a TPU (polyurethane) matrix, with a Shore hardness of 45A, Si-TPV 3100-45A, Chengdu Silike. Silicone-based thermoplastic elastomer B: Silicone rubber particles are dispersed in a TPU (polyurethane) matrix, with a Shore hardness of 53A, Si-TPV 3100-55A, Chengdu Silike. Silicone-based thermoplastic elastomer C: Silicone rubber particles are dispersed in a TPU (polyurethane) matrix, with a Shore hardness of 60A, Si-TPV 3100-60A, Chengdu Silike. Silicone-based thermoplastic elastomer D: Silicone rubber particles are dispersed in a TPU (polyurethane) matrix, with a Shore hardness of 63A, Si-TPV 3100-65A, Chengdu Silike; Silicone-based thermoplastic elastomer E: Silicone rubber particles are dispersed in a TPO (polyolefin) matrix, with a Shore hardness of 70A, Si-TPV2150-70A, Chengdu Silike; α-Polyolefin A: A copolymer of ethylene, propylene, and 1-butene, with a tensile strength of 1.5 MPa, VESTOPLAST 751, Evonik Technologies; α-Polyolefin B: A copolymer of ethylene, propylene, and 1-butene, with a tensile strength of 2.0 MPa, VESTOPLAST 891, Evonik Technologies; α-Polyolefin C: A copolymer of ethylene, propylene, and 1-butene, with a tensile strength of 2.5 MPa, VESTOPLAST 888, Evonik Technologies; α-Polyolefin D: A copolymer of ethylene, propylene, and 1-butene, with a tensile strength of 5.0 MPa, VESTOPLAST 750, Evonik Technologies; Silane-modified α-polyolefin: The copolymer of ethylene, propylene, and 1-butene is modified with siloxane, with a tensile strength of 1.9 MPa, VESTOPLAST 206, Evonik Technologies; Ethylene-octene copolymer: POE 8842, Dow Chemical; Porous graphene: XF269, Xianfeng Nano; Talcum powder: TYT-777A, Beihai Group; Wollastonite: TREMIN 939, HPF Germany; Mica powder: 60-D, Huajing Mica; Barium sulfate: Commercially available; Antioxidant 1010: Commercially available; Antioxidant 168: Commercially available; Light stabilizer: UV-3808PP5, Cytec.

[0051] Examples and comparative examples The components and parts by weight of the polypropylene compositions of the examples and comparative examples are selected as shown in Table 1 and Table 2. Among them, the preparation method of the polypropylene compositions of the examples and comparative examples includes the following steps: After mixing the components evenly according to Table 1 and Table 2, the obtained mixture is added to a twin-screw extruder for melt extrusion granulation to obtain the polypropylene composition; among them, the length-diameter ratio of the twin-screw extruder is 40:1, the screw speed is 400 rpm, and the extrusion temperature is 200-220 °C.

[0052] The polypropylene compositions obtained in the examples and comparative examples were subjected to performance tests, and the test methods were as follows: (1) Flexural modulus: The polypropylene composition was injection-molded into a sample piece of 80 mm * 10 mm * 4 mm, and tested in accordance with the standard ISO 178-2010. The test conditions were: 23 °C, bending speed 2 mm / min; (2) Izod notched impact strength: The polypropylene composition was injection-molded into a sample piece of 80 mm * 10 mm * 4 mm, and tested in accordance with the standard ISO180-2019. The test conditions were: Type A notch, -30 °C, pendulum energy 4 J; (3) TVOC: The polypropylene compositions of the examples and comparative examples were injection-molded into 4 kg sample plates at 230 °C, and the TVOC (C6-C16) in the sample plates was tested using a 2000 L sample bag in accordance with the standard CVTC54072-2015.

[0053] The test results are shown in Tables 1 and 2.

[0054] Table 1 Table 2 From the experimental data in Tables 1 and 2, it can be seen that the 23 °C flexural modulus of the polypropylene composition of the present invention is ≥ 1700 MPa, the Izod notched impact strength at -30 °C is ≥ 6 kJ / m 2 , and the TVOC is ≤ 3000 μg / m 3 , indicating that the polypropylene composition of the present invention has good low-temperature toughness and low odor.

[0055] Comparing Examples 3-7, it can be seen that for the polypropylene composition prepared from a silicone-based thermoplastic elastomer with a Shore hardness of 40-65A, its 23 °C flexural modulus is ≥ 1750 MPa, the Izod notched impact strength at -30 °C is ≥ 6 kJ / m 2 , and the TVOC is ≤ 2600 μg / m 3 , indicating that when the Shore hardness of the silicone-based thermoplastic elastomer is 40-65A, the polypropylene composition has good low-temperature toughness and low odor.

[0056] Comparing Example 4 and Examples 8-10, it can be seen that for the polypropylene composition prepared from an α-olefin with a tensile strength of 1.5-5, its 23 °C flexural modulus is ≥ 1700 MPa, the Izod notched impact strength at -30 °C is ≥ 6.3 kJ / m 2 , and the TVOC is ≤ 2700 μg / m 3 , indicating that when the tensile strength of the α-olefin is 1.5-5, the polypropylene composition has good low-temperature toughness and low odor.

[0057] Comparing Comparative Example 4 and Example 11, it can be seen that for the polypropylene composition prepared from silane-modified α-polyolefin, its flexural modulus at 23°C ≥ 1800 MPa, and its Izod notched impact strength at -30°C ≥ 7 kJ / m 2 , and TVOC ≤ 2000 μg / m 3 , indicating that when α-polyolefin is silane-modified, the polypropylene composition has good low-temperature toughness and low odor.

[0058] Comparing Comparative Example 4, Example 12 - 13 and Comparative Example 6, it can be seen that when the filler is a silicate filler, the flexural modulus at 23°C of the obtained polypropylene composition ≥ 1700 MPa, and its Izod notched impact strength at -30°C ≥ 6 kJ / m 2 , and TVOC ≤ 3000 μg / m 3 , indicating that when a silicate filler is selected as the filler, the rigidity and low odor of the polypropylene composition can be improved.

[0059] Comparing Comparative Example 4 and Comparative Examples 1 - 5, it can be seen that when at least one of the silicone-based thermoplastic elastomer, α-polyolefin, and porous graphene is missing, or other analogues are used to replace the silicone-based thermoplastic elastomer or α-polyolefin, the Izod notched impact strength at -30°C of the obtained polypropylene composition ≤ 5 kJ / m 2 , and TVOC ≥ 3500 μg / m 3 , indicating that when at least one of the silicone-based thermoplastic elastomer, α-polyolefin, and porous graphene is missing, or other analogues are used to replace the silicone-based thermoplastic elastomer or α-polyolefin, the polypropylene composition cannot have good low-temperature toughness and low odor.

[0060] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composition, characterized in that, Comprising the following components in parts by weight: 33-72 parts of polypropylene, 8-32 parts of silicone-based thermoplastic elastomer, 5-15 parts of α-olefin, 5-15 parts of porous graphene, 5-25 parts of silicate filler, 0.1-1 part of additives; wherein the α-olefin is a copolymer of ethylene, propylene and 1-butene.

2. The polypropylene composition according to claim 1, wherein The Shore hardness of the silicone-based thermoplastic elastomer is 40-70A.

3. The polypropylene composition according to claim 1, characterized in that, The tensile strength of the α-olefin is 1.5-5 MPa.

4. The polypropylene composition according to claim 1, wherein The silicate filler is at least one of talc, wollastonite, kaolin, mica.

5. The polypropylene composition according to claim 1, characterized in that, The additives are at least one of lubricants, antioxidants, light stabilizers.

6. The polypropylene composition according to claim 5, characterized in that, The lubricant is at least one of low molecular weight ester lubricants, metal soap lubricants, stearic acid composite ester lubricants, amide lubricants; and / or, the antioxidant is at least one of phenolic antioxidants, phosphite antioxidants, divalent sulfur antioxidants; and / or, the light stabilizer is a hindered amine light stabilizer.

7. The polypropylene composition according to claim 1, characterized in that, The melt mass flow rate of the polypropylene at 230 °C under a load of 2.16 kg is 1-100 g / 10 min.

8. A method for preparing a polypropylene composition according to any one of claims 1-7, characterized in that, Comprising the following steps: After mixing each component evenly, the obtained premix is added to a screw extruder, melt extruded and pelletized to obtain a polypropylene composition.

9. Use of the polypropylene composition according to any one of claims 1-7 in the preparation of automotive interior parts.

10. An automotive interior, characterized in that, The automotive interior comprises the polypropylene composition according to any one of claims 1-7.

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