Low-temperature-resistant polypropylene impact-resistant modified material, preparation method thereof and automobile part

Abstract

The invention relates to the field of composite materials, in particular to a low-temperature-resistant polypropylene impact-resistant modified material, a preparation method thereof and an automobile part. The low-temperature-resistant polypropylene impact-resistant modified material provided by the invention is prepared from the following raw materials in parts by mass: 60-98 parts of homo-polypropylene; 5-15 parts of an ethylene-butylene copolymer elastomer; 1 to 10 parts of an SEPS elastomer; 0-30 parts, but not 0 part, of hydrated magnesium silicate; 0.1 to 1 part of a silane coupling agent; 0-8 parts of grafted polyethylene, but not 0 part; 0.1 to 1 part of an antioxidant; and 0.1-1 part of a processing aid. The low-temperature-resistant polypropylene anti-impact modified material provided by the invention can effectively improve the low-temperature-resistant and anti-impact properties, and meanwhile, good tensile property, bending property and high-temperature property are ensured.

Description

Technical Field

[0001] The present invention relates to the field of composite materials, and in particular to a low-temperature resistant polypropylene impact-modified material and a preparation method thereof, as well as automobile parts. Background Art

[0002] Polypropylene (PP), a widely used general-purpose plastic made from the polymerization of propylene monomer, has a melting point of 165-175°C and is a semi-crystalline plastic. Polypropylene, characterized by its lightweight and easy processing, is widely used in machinery, automobiles, electronics, construction, textiles, and packaging. It has become the most widely used and fastest-growing plastic in automotive applications. However, polypropylene suffers from poor low-temperature resistance and low rigidity, failing to meet the requirements and standards for automotive interior components.

[0003] Automobile parts are increasingly concerned about safety performance. Automobile interior parts include instrument panels, auxiliary instrument panels, A, B and C pillars, glove boxes, door panels, trunk panels, etc. When the car is subjected to unexpected impact energy from outside the car, it is necessary to ensure that the instrument panel will deploy the airbag in time to protect the driver and passengers from damage to a minimum, and at the same time, the driver and passengers must not be injured due to fragments or sharp angles caused by damage. Therefore, automobile interior parts must meet certain low-temperature impact resistance requirements, especially low-temperature impact performance from 0°C to -40°C. The low-temperature toughness of materials has become a priority performance in automobile interior materials, especially in the design of hard instrument panels. At present, the low-temperature impact of materials is mainly characterized by the cantilever beam (simply supported beam) impact strength. The low-temperature cantilever notch impact strength (-30°C) of the current polypropylene material specially used for instrument panels is 4KJ / m 2 Under the conditions of multi-axial impact of 6.6m / s and -30℃, the fracture form is brittle fracture; with the continuous improvement of the requirements for automotive interior parts, more and more OEMs will have requirements for the multi-axial impact performance of materials.

[0004] Currently, polypropylene (PP) modification can overcome its low-temperature brittleness and improve its overall performance to meet various application requirements. Modified PP has been widely used in applications such as automobiles and home appliances. Common methods for improving PP's low-temperature impact resistance include: 1) blending with polyethylene (PE). PE's low-temperature brittleness temperature can reach -35°C. While adding an appropriate amount of PE can improve PP's low-temperature resistance, excessive PE addition can affect the hardness of PP products. 2) toughening with polyolefin (POE). POE exhibits the general properties of thermoplastic elastomers, including low density, excellent heat and cold resistance, and a wide operating temperature range. It is an ideal material for improving PP's low-temperature resistance. Typically, adding 3%-15% can achieve a -20°C PP toughness. Using cold-resistant POE to toughen PP not only improves the original PP's low-temperature resistance but also improves its impact strength. However, POE has a glass transition temperature of approximately -50°C and a crystallinity of approximately 5-8%. For products requiring lower operating temperatures, the addition of POE must be increased, which can result in a decrease in mechanical properties such as flexural strength. 3) EPDM toughening. EPDM's key attributes are its superior resistance to oxidation, ozone, and erosion, as well as its resistance to low-temperature embrittlement. Using EPDM cold-resistant particles to improve PP's low-temperature resistance to temperatures as low as -40°C is possible. While the cost is higher than POE, the performance is incomparable. As can be seen, when modifying polypropylene, improving one property often compromises other aspects, making it difficult to achieve a balance between low-temperature resistance, hardness, and mechanical properties, and resulting in higher costs.

[0005] Chinese patent publication number CN102796320 discloses a low-temperature impact-resistant polypropylene composition, its preparation method, and its application. The polypropylene composition is prepared from 40-80% polypropylene, 5-30% elastomer, 0-40% inorganic filler, and 3-15% low-temperature impact modifier. The low-temperature impact modifier is a ternary alloy blend of polypropylene, polyethylene, and ethylene-α-olefin homopolymer. The addition of the low-temperature impact modifier significantly lowers the brittle-to-ductile transition temperature of the material, expanding the temperature range of its use as a tough material. While improving the low-temperature impact toughness, the material's rigidity is maintained, fully meeting the requirements of the automotive industry. However, there are few reports on the use of modified polypropylene in plastic seals, and no patents related to modified polypropylene materials for plastic seals have been found. Summary of the Invention

[0006] In view of this, the present invention provides a low-temperature resistant polypropylene impact-modified material, a preparation method thereof, and an automotive component. The low-temperature resistant polypropylene impact-modified material provided by the present invention can effectively improve low-temperature resistance and impact resistance while ensuring good tensile properties, bending properties, and high-temperature performance.

[0007] The present invention provides a low-temperature resistant polypropylene impact-modified material, wherein the raw materials for preparing the material include, in parts by mass:

[0008]

[0009]

[0010] Preferably, the melt flow rate of the ethylene-butene copolymer elastomer is 5 to 25 g / 10 min at 190° C. and 2.16 kg; the density of the ethylene-butene copolymer elastomer is 0.85 to 0.88 g / cm 3 .

[0011] Preferably, the ethylene-butene copolymer elastomer is Bioelastomer G6012.

[0012] Preferably, the melt flow rate of the SEPS elastomer is 1 to 10 g / 10 min at 190° C. and 2.16 kg; the glass transition temperature of the SEPS elastomer is -60 to -65° C.; the density of the SEPS elastomer is 0.850 to 0.920 kg / m 3 .

[0013] Preferably, the whiteness of the hydrated magnesium silicate is 80-95, the mass percentage of silicon dioxide is 50%-60%, the particle size D50 is 8-15 μm, and the aspect ratio is 15-30.

[0014] Preferably, the grafted polyethylene is maleic anhydride grafted polyethylene;

[0015] The melt flow rate of the grafted polyethylene is 2 to 10 g / 10 min at 190° C. and 2.16 kg;

[0016] The grafting rate of maleic anhydride in the grafted polyethylene is 0.3% to 1.5%.

[0017] Preferably, the silane coupling agent is KH570;

[0018] The antioxidants are Irganox 1010 and Irganox 168.

[0019] Preferably, the processing aid is at least one of zinc stearate, magnesium stearate, calcium stearate, polydimethylsiloxane, EBS and oleamide.

[0020] The present invention also provides a method for preparing the low-temperature resistant polypropylene impact-modified material described in the above technical solution, comprising the following steps:

[0021] A) homopolypropylene, ethylene-butene copolymer elastomer, SEPS elastomer, hydrated magnesium silicate, grafted polyethylene, silane coupling agent, antioxidant and processing aid are mixed to obtain a compound;

[0022] B) feeding the mixed material into a twin-screw extruder, melting, plasticizing and granulating to obtain a low-temperature resistant polypropylene impact-modified material.

[0023] The present invention also provides an automobile component, the raw materials for preparing the automobile component include the low-temperature resistant polypropylene impact-modified material described in the above technical solution;

[0024] The automobile component is a seal or an automobile bumper.

[0025] The low-temperature resistant polypropylene impact modifier provided by the present invention is prepared by combining homopolypropylene, ethylene-butene copolymer elastomer, SEPS elastomer, hydrated magnesium silicate, silane coupling agent, grafted polyethylene, antioxidant and processing aid in a certain proportion. It uses SEPS elastomer and ethylene-butene copolymer elastomer as impact modifiers, and combines with other components to greatly improve the low-temperature impact resistance of homopolypropylene, so that the product can reach a low-temperature resistance of -35°C, while the low-temperature use temperature of traditional POE toughened polypropylene modified material products is only about -20°C. Compared with this, the present invention greatly improves the low-temperature impact resistance. While improving the low-temperature impact resistance, the polypropylene impact modifier of the present invention also has good tensile strength, flexural strength and high-temperature performance; in addition, the main raw materials used include homopolypropylene, ethylene-butene homopolymer elastomer, etc., and the market cost is lower than that of copolymer polypropylene in existing conventional formulas, which reduces costs and has higher market competitiveness. In addition, the preparation method of the present invention adopts twin-screw melt extrusion, which is simple to operate and easy to control, and is suitable for industrial production.

[0026] The test results show that the low-temperature resistant polypropylene impact-modified material obtained by the present invention has a notched impact strength of 40kJ / m at room temperature. 2 Above, the notched impact strength reaches 5kJ / m at low temperature -35℃ 2 The above-mentioned materials have excellent impact resistance at both room and low temperatures. Furthermore, their tensile strength exceeds 14.5 MPa, their breaking strength exceeds 10 MPa, their elastic modulus exceeds 1328 MPa, and their flexural strength exceeds 22.5 MPa, demonstrating excellent tensile and flexural properties. Furthermore, their load deflection temperature exceeds 89°C, demonstrating excellent high-temperature resistance. DETAILED DESCRIPTION

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0028] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0029] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] As used herein, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0031] In this document, when referring to a range, if the unit is followed only by the right endpoint, it means that the units for both the left and right endpoints are the same. For example, 1-10 g / 10 min means that the units for both the left endpoint "1" and the right endpoint "10" are g / 10 min.

[0032] The present invention provides a low-temperature resistant polypropylene impact-modified material, wherein the raw materials for preparing the material include, in parts by mass:

[0033]

[0034] About homopolymer polypropylene:

[0035] In the present invention, the melt flow rate (melt index) of the homopolypropylene is preferably 5 to 50 g / 10 min at 230°C × 2.16 kg, specifically 5 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 37 g / 10 min, 40 g / 10 min, 45 g / 10 min, and more preferably 35 to 45 g / 10 min. The present invention uses the homopolypropylene with suitable fluidity as the base resin of the modified material, which can ensure that the material has good mechanical properties while ensuring the processing performance requirements of the material. The present invention has no special restrictions on the source of the homopolypropylene, and it can be a commercial product or prepared according to conventional preparation methods in the field. In some embodiments of the present invention, the homopolypropylene has a melt index (230° C., 2.16 kg) of 37 g / 10 min, a melting point of 165° C., and a brand name of BX3900.

[0036] In the present invention, the amount of the homopolypropylene is 60 to 98 parts, specifically 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, and 98 parts.

[0037] About Ethylene-Butene Copolymer Elastomer:

[0038] In the present invention, the elongation at break of the ethylene-butene copolymer elastomer is preferably greater than 600%, and the content of butene homomonomer in the ethylene-butene copolymer elastomer is preferably 20% to 30%. Based on the elongation of the elastomer and the content of ethylene-butene groups, the melt flow rate of the ethylene-butene copolymer elastomer is preferably 5 to 25 g / 10 min at 190°C x 2.16 kg; the density of the ethylene-butene copolymer elastomer is preferably 0.85 to 0.88 g / cm 3 The ethylene-butene copolymer elastomer is a thermoplastic elastomer with excellent low-temperature resistance. It is an ethylene-butene homopolymer synthesized by combining metallocene catalysis technology with optimized solvent technology. In the present invention, the most preferred ethylene-butene copolymer elastomer is the polyolefin elastomer G6012 produced by Hainan Beiouyi Technology Co., Ltd.

[0039] In the present invention, the amount of the ethylene-butene copolymer elastomer is 5 to 15 parts, specifically 5 parts, 6 parts, 7 parts, 7.5 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, preferably 5 to 10 parts.

[0040] About SEPS elastomer:

[0041] In the present invention, the SEPS elastomer is a high molecular weight polymer of hydrogenated styrene and isoprene, and after hydrogenation, the composition is polystyrene (S) - polyethylene (E) - polypropylene (P) - polystyrene (S). In the present invention, the melt index (190°C, 2.16kg) of the SEPS elastomer is preferably 1 to 10g / 10min, specifically 1g / 10min, 1.5g / 10min, 2g / 10min, 3g / 10min, 4g / 10min, 5g / 10min, 6g / 10min, 7g / 10min, 8g / 10min, 9g / 10min, 10g / 10min. The glass transition temperature (Tg) of the SEPS elastomer is preferably -60 to -65°C, specifically -60°C, -61°C, -62°C, -63°C, -64°C, -65°C. The density of the SEPS elastomer is preferably 0.850 to 0.920kg / m 3 , specifically 0.850kg / m 3 , 0.860kg / m 3 、0.870kg / m 3 、0.880kg / m 3 、0.890kg / m 3 , 0.900kg / m 3 、0.910kg / m 3 , 0.920kg / m 3 In some embodiments of the present invention, the melt index (190°C, 2.16 kg) of the SEPS elastomer is 1.5 g / 10 min, the glass transition temperature is -65°C, and the density is 0.92 kg / m 3 , brand LCY8550U.

[0042] In the present invention, the amount of the SEPS elastomer is 1 to 10 parts, specifically 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 7.5 parts, 8 parts, 9 parts, 10 parts, preferably 5 to 10 parts.

[0043] About Hydrated Magnesium Silicate:

[0044] In the present invention, the whiteness of the hydrated magnesium silicate is preferably 80-95, the mass percentage of silicon dioxide is preferably 50%-60%, the particle size D50 is preferably 8-15 μm, and the aspect ratio is preferably 15-30. The hydrated magnesium silicate of the above specifications can be provided by Liaoning Aihai Talc Co., Ltd. under the product name Aihai Ultrafine Talc.

[0045] In the present invention, the amount of the hydrated magnesium silicate is 0 to 30 parts, and is not 0 parts. Specifically, it can be 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, or 30 parts.

[0046] About silane coupling agent:

[0047] In the present invention, the silane coupling agent is preferably KH570. In the present invention, the amount of the silane coupling agent is 0.1 to 1 part, specifically 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, or 1.0 part.

[0048] About Grafted Polyethylene:

[0049] In the present invention, the grafted polyethylene is a graft polymer comprising LDPE (low-density polyethylene) as a base material grafted with maleic anhydride as a polar monomer, i.e., maleic anhydride-grafted polyethylene. In the present invention, the melt flow rate of the grafted polyethylene is preferably 2 to 10 g / 10 min at 190° C. × 2.16 kg, and can specifically be 2 g / 10 min, 3 g / 10 min, 3.6 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min, or 10 g / 10 min. In the present invention, the grafting rate of maleic anhydride (MAH) in the grafted polyethylene is preferably 0.3% to 1.5%, specifically 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, and 1.5%. The introduction of the above-mentioned grafted polyethylene in the present invention can improve the compatibility between homopolypropylene and the inorganic fillers and various polar colorants used in the present invention, thereby improving the mechanical strength and color fastness of the material. The present invention has no special restrictions on the source of the grafted polyethylene, which can be a commercial product or prepared according to conventional preparation methods in the field. In some embodiments of the present invention, the maleic anhydride grafted polyethylene (PE-g-MAH) has a melt index (190°C, 2.16kg) of 3.6g / 10min and a grafting rate of 1.5%, and is sourced from Tianfeng New Materials Co., Ltd.

[0050] In the present invention, the amount of the grafted polyethylene is 0 to 8 parts, and is not 0 parts; specifically, it can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, or 8 parts.

[0051] About antioxidants:

[0052] In the present invention, the antioxidant is preferably a hindered phenolic antioxidant. Its structure contains an —OH functional group. Due to the electron-repelling groups introduced at the ortho and para positions, the hydrogen atoms are highly reactive. The reactivity of the H atoms in these hydroxyl groups must be greater than that of the H atoms in RH to prevent the reaction between R·, ROO·, and RH, thereby preventing the oxidative degradation of RH. Most preferably, the antioxidants are Irganox 1010 and Irganox 168. The mass ratio of Irganox 1010 to Irganox 168 is preferably 1:1. The source of the antioxidant is not particularly limited; commercially available products are sufficient.

[0053] In the present invention, the amount of the antioxidant is 0.1 to 1 part, specifically 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, or 1.0 part.

[0054] About processing aids:

[0055] In the present invention, the processing aid is preferably at least one of zinc stearate, magnesium stearate, calcium stearate, polydimethylsiloxane, EBS (i.e., vinyl bisstearamide), and oleamide, and more preferably EBS. The present invention does not particularly limit the source of the processing aid; it can be a commercially available product.

[0056] In the present invention, the amount of the processing aid is 0.1 to 1 part, specifically 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, or 1.0 part.

[0057] In one embodiment of the present invention, the raw material of the low temperature resistant polypropylene impact modified material is:

[0058] In another embodiment of the present invention, the raw material of the low temperature resistant polypropylene impact modified material is:

[0059] In another embodiment of the present invention, the raw material of the low temperature resistant polypropylene impact modified material is:

[0060] In one embodiment of the present invention, the raw materials of the low temperature resistant polypropylene impact modified material are:

[0061]

[0062]

[0063] in,

[0064] Homopolymer polypropylene: melt index (230℃, 2.16kg): 37g / 10min, melting point 165℃; brand BX3900;

[0065] Ethylene-butene copolymer elastomer: Beiouyi G6012;

[0066] SEPS elastomer: Melt index (230°C, 2.16kg): 1.5g / 10min; Tg: -65°C; Density 0.92kg / m 3 ; Brand LCY8550U;

[0067] Hydrated magnesium silicate: whiteness 80-95, silicon dioxide content 50%-60% by mass, particle size D50 8-15 μm, aspect ratio 15-30; product name: Aihai Ultrafine Talc;

[0068] Silane coupling agent: KH570;

[0069] Maleic anhydride grafted polyethylene: melt index (190°C, 2.16 kg): 3.6 g / 10 min; grafting rate 1.5%;

[0070] Antioxidants: Irganox 1010 and Irganox 168; the mass ratio of the two is 1:1;

[0071] Processing aid: zinc stearate.

[0072] In another embodiment of the present invention, the raw material of the low temperature resistant polypropylene impact modified material is:

[0073]

[0074] in,

[0075] Homopolymer polypropylene: melt index (230℃, 2.16kg): 37g / 10min, melting point 165℃; brand BX3900;

[0076] Ethylene-butene copolymer elastomer: Beiouyi G6012;

[0077] SEPS elastomer: Melt index (230°C, 2.16kg): 1.5g / 10min; Tg: -65°C; Density 0.92kg / m 3 ; Brand LCY8550U;

[0078] Hydrated magnesium silicate: whiteness 80-95, silicon dioxide content 50%-60% by mass, particle size D50 8-15 μm, aspect ratio 15-30; product name: Aihai Ultrafine Talc;

[0079] Silane coupling agent: KH570;

[0080] Maleic anhydride grafted polyethylene: melt index (190°C, 2.16 kg): 3.6 g / 10 min; grafting rate 1.5%;

[0081] Antioxidants: Irganox 1010 and Irganox 168; the mass ratio of the two is 1:1;

[0082] Processing aid: zinc stearate.

[0083] In another embodiment of the present invention, the raw material of the low temperature resistant polypropylene impact modified material is:

[0084]

[0085] in,

[0086] Homopolymer polypropylene: melt index (230℃, 2.16kg): 37g / 10min, melting point 165℃; brand BX3900;

[0087] Ethylene-butene copolymer elastomer: Beiouyi G6012;

[0088] SEPS elastomer: Melt index (230°C, 2.16kg): 1.5g / 10min; Tg: -65°C; Density 0.92kg / m 3 ; Brand LCY8550U;

[0089] Hydrated magnesium silicate: whiteness 80-95, silicon dioxide content 50%-60% by mass, particle size D50 8-15 μm, aspect ratio 15-30; product name: Aihai Ultrafine Talc;

[0090] Silane coupling agent: KH570;

[0091] Maleic anhydride grafted polyethylene: melt index (190°C, 2.16 kg): 3.6 g / 10 min; grafting rate 1.5%;

[0092] Antioxidants: Irganox 1010 and Irganox 168; the mass ratio of the two is 1:1;

[0093] Processing aid: zinc stearate.

[0094] The present invention also provides a method for preparing the low-temperature resistant polypropylene impact-modified material described in the above technical solution, comprising the following steps:

[0095] A) homopolypropylene, ethylene-butene copolymer elastomer, SEPS elastomer, hydrated magnesium silicate, grafted polyethylene, silane coupling agent, antioxidant and processing aid are mixed to obtain a compound;

[0096] B) feeding the mixed material into a twin-screw extruder, melting, plasticizing and granulating to obtain a low-temperature resistant polypropylene impact-modified material.

[0097] Regarding step A): The types and amounts of the homopolypropylene, ethylene-butene copolymer elastomer, SEPS elastomer, hydrated magnesium silicate, grafted polyethylene, silane coupling agent, antioxidant, and processing aid are consistent with those described in the previous technical solution and are not detailed here. Mixing can be performed by stirring in a high-speed mixer. The mixing conditions are not particularly limited; they can simply be used to uniformly mix the materials. After uniform mixing, a mixture is obtained.

[0098] Regarding step B): There is no special limitation on the twin-screw extruder, and it can be a general equipment in this field. The mixed material is fed into the twin-screw extruder by a feeder, and the residence time of the material in the screw is preferably 50 to 120 seconds. Preferably, the temperature of the twin-screw extruder from the feed section to the die is: 175 to 185°C, 210 to 220°C, 210 to 220°C, 210 to 220°C, 210 to 220°C, 210 to 220°C, 210 to 220°C, 210 to 220°C, and the temperature of the die is 215 to 225°C. The screw speed is preferably 140 to 600 r / min, specifically 600 r / min. The mixed material obtained in step A) is put into a twin-screw extruder, melted and plasticized, and then melted and extruded from the twin-screw extruder, and then cooled, dried and pelletized to obtain a granular material, i.e., a low-temperature resistant polypropylene impact modified material.

[0099] The present invention also provides a seal, the raw materials for which include the low-temperature-resistant impact-modified polypropylene material described in the above technical solution. Seals are common components in automobiles, but the use of modified polypropylene in plastic seals is rare in the prior art. The low-temperature-resistant impact-modified polypropylene material provided by the present invention can be used to manufacture seals, meeting the requirements of automotive use.

[0100] The present invention also provides a method for preparing the seal described in the above technical solution, comprising: pressing a modified polypropylene material into a mold and performing injection molding using an injection molding machine to obtain a seal. The injection molding process preferably comprises: the temperatures of the injection molding machine from the rear section to the nozzle are, in order, 195-205°C, 205-215°C, 210-220°C, and 215-225°C; the mold temperature is 30-40°C; the injection pressure is 60-80 MPa, and the injection speed is 50%-70%; the injection speed is expressed as a percentage of the machine's maximum speed. A single injection molding process is performed on the injection molding machine to obtain a preformed material, which is then post-processed to obtain the seal.

[0101] The present invention also provides an automobile bumper, the raw materials for preparing the bumper include the low-temperature resistant polypropylene impact-modified material described in the above technical solution.

[0102] The low-temperature resistant polypropylene impact modifier provided by the present invention is prepared by combining homopolypropylene, ethylene-butene copolymer elastomer, SEPS elastomer, hydrated magnesium silicate, silane coupling agent, grafted polyethylene, antioxidant and processing aid in a certain proportion. It uses SEPS elastomer and ethylene-butene copolymer elastomer as impact modifiers, and combines with other components to greatly improve the low-temperature impact resistance of homopolypropylene, so that the product can reach a low-temperature resistance of -35°C, while the low-temperature use temperature of traditional POE toughened polypropylene modified material products is only about -20°C. Compared with this, the present invention greatly improves the low-temperature impact resistance. While improving the low-temperature impact resistance, the polypropylene impact modifier of the present invention also has good tensile strength, flexural strength and high-temperature performance; in addition, the main raw materials used include homopolypropylene, ethylene-butene homopolymer elastomer, etc., and the market cost is lower than that of copolymer polypropylene in existing conventional formulas, which reduces costs and has higher market competitiveness. In addition, the preparation method of the present invention adopts twin-screw melt extrusion, which is simple to operate and easy to control, and is suitable for industrial production.

[0103] The test results show that the low-temperature resistant polypropylene impact-modified material obtained by the present invention has a notched impact strength of 40kJ / m at room temperature. 2 Above, the notched impact strength reaches 5kJ / m at low temperature -35℃ 2 The above-mentioned materials have excellent impact resistance at both room and low temperatures. Furthermore, their tensile strength exceeds 14.5 MPa, their breaking strength exceeds 10 MPa, their elastic modulus exceeds 1328 MPa, and their flexural strength exceeds 22.5 MPa, demonstrating excellent tensile and flexural properties. Furthermore, their load deflection temperature exceeds 89°C, demonstrating excellent high-temperature resistance.

[0104] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0105] Example 1

[0106] 1. Raw materials

[0107] The types and amounts of raw materials used in Example 1 are shown in Table 1:

[0108] Table 1: Raw materials for Example 1

[0109]

[0110] 2. Preparation

[0111] A) Homopolypropylene, ethylene-butene copolymer elastomer, SEPS elastomer, hydrated magnesium silicate, grafted polyethylene, silane coupling agent, antioxidant and processing aid are added into a high-speed mixing pot and stirred to obtain a mixture.

[0112] B) The mixed material obtained in step A) is fed into a twin-screw extruder via a feeder. The material resides in the screw for 50 to 120 seconds. The temperatures of the twin-screw extruder from the feed section to the die are, in sequence, 180°C, 215°C, 215°C, 215°C, 215°C, 215°C, 215°C, and 215°C. The die temperature is 220°C. After high-speed shearing and mixing at a speed of 600 r / min, the material is extruded from the die, stretched into strands, air-cooled, dried, pelletized, and packaged to obtain a low-temperature-resistant polypropylene impact-modified material.

[0113] Example 2

[0114] 1. Raw materials

[0115] The types and amounts of raw materials used in Example 2 are shown in Table 2:

[0116] Table 2: Raw materials for Example 2

[0117]

[0118] 2. Preparation: Same as Example 1.

[0119] Example 3

[0120] 1. Raw materials

[0121] The types and amounts of raw materials used in Example 3 are shown in Table 3:

[0122] Table 3: Raw materials for Example 3

[0123]

[0124] 2. Preparation: Same as Example 1.

[0125] Comparative Example 1

[0126] The method is implemented in accordance with Example 1, except that the SEPS elastomer is replaced by an ethylene-butene homopolymer elastomer, that is, the impact modifier is entirely an ethylene-butene homopolymer elastomer.

[0127] Comparative Example 2 was implemented in the same manner as Example 1, except that the ethylene-butene homopolymer elastomer was replaced with a SEPS elastomer, that is, the impact modifier was entirely SEPS elastomer.

[0128] Product Testing :

[0129] The polypropylene modified materials obtained in each example and comparative example were prepared into test bars using an injection molding machine. Notched impact strength bars were prepared according to GB / T 1043.1-2008, and notched impact strength testing was performed according to this standard. Tensile strength bars were prepared according to GB / T 1040.1-2018, and tensile properties were tested according to this standard. Flexural modulus bars were prepared according to GB / 9341-2008, and flexural properties were tested according to this standard.

[0130] The test results of each embodiment are shown in Table 4:

[0131] Table 4: Test results of the example products

[0132]

[0133] It can be seen from the test results in Table 4 that the low-temperature resistant polypropylene impact-modified material obtained in the present invention has excellent impact resistance at both room temperature and low temperature, especially the notched impact strength reaches 5kJ / m at low temperature of -35°C. 2 Above, the notched impact strength at room temperature reaches 40kJ / m 2 At the same time, its tensile strength reaches more than 14.5MPa, its yield strength reaches more than 14.5MPa, its breaking strength reaches more than 10MPa, its elastic modulus reaches more than 1328MPa, and its bending strength reaches more than 22.5MPa; it shows excellent tensile and bending properties. Moreover, its load deformation temperature reaches more than 89°C, and it has excellent high temperature resistance. Among them, the low temperature impact resistance and high temperature resistance of Examples 2-3 are further improved, reaching 5.3kJ / m 2 and above 91°C. The low-temperature impact resistance and high-temperature resistance of Example 3 are the best, reaching 6.68kJ / m 2 and 92.3℃, and maintain excellent tensile and flexural properties.

[0134] The test results of each comparative example are shown in Table 5:

[0135] Table 5: Test results of comparative products

[0136] Comparative Example 1 <![CDATA[Izod impact strength at low temperature (-35°C): 3.76 kJ / m 2 > Comparative Example 2 Tensile strength: 11.87MPa; load deformation temperature: 87℃

[0137] It can be seen from the test results in Table 5 that the low-temperature impact resistance of Comparative Example 1 is significantly reduced, the tensile strength of Comparative Example 2 is significantly reduced, and the high-temperature resistance is also reduced. This proves that the present invention adopts a combination of SEPS elastomer and ethylene-butene homopolymer elastomer to make the material have both low-temperature impact resistance, tensile properties and high-temperature resistance.

[0138] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal description of the claims, or if they include equivalent structural elements that are not substantially different from the literal description of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A low-temperature resistant polypropylene impact modified material, characterized in that: The raw materials for its preparation include, by mass:

2. The low-temperature resistant polypropylene impact-modified material according to claim 1, characterized in that: The melt flow rate of the ethylene-butene copolymer elastomer is 5 to 25 g / 10 min at 190° C. and 2.16 kg; the density of the ethylene-butene copolymer elastomer is 0.85 to 0.88 g / cm 3 .

3. The low-temperature resistant polypropylene impact-modified material according to claim 1 or 2, characterized in that: The ethylene-butene copolymer elastomer is Bioe G6012.

4. The low-temperature resistant polypropylene impact-modified material according to claim 1, characterized in that: The melt flow rate of the SEPS elastomer is 1 to 10 g / 10 min at 190° C. and 2.16 kg; the glass transition temperature of the SEPS elastomer is -60 to -65° C.; the density of the SEPS elastomer is 0.850 to 0.920 kg / m 3 .

5. The low-temperature resistant polypropylene impact-modified material according to claim 1, characterized in that: The whiteness of the hydrated magnesium silicate is 80-95, the mass percentage of silicon dioxide is 50%-60%, the particle size D50 is 8-15 μm, and the aspect ratio is 15-30.

6. The low-temperature resistant polypropylene impact-modified material according to claim 1, characterized in that: The grafted polyethylene is maleic anhydride grafted polyethylene; The melt flow rate of the grafted polyethylene is 2 to 10 g / 10 min at 190° C. and 2.16 kg; The grafting rate of maleic anhydride in the grafted polyethylene is 0.3% to 1.5%.

7. The low-temperature resistant polypropylene impact-modified material according to claim 1, characterized in that: The silane coupling agent is KH570; The antioxidants are Irganox 1010 and Irganox 168.

8. The low-temperature resistant polypropylene impact-modified material according to claim 1, characterized in that: The processing aid is preferably at least one of zinc stearate, magnesium stearate, calcium stearate, polydimethylsiloxane, EBS and oleamide.

9. A method for preparing a low-temperature resistant polypropylene impact-modified material according to any one of claims 1 to 8, characterized in that: The following steps are involved: A) homopolypropylene, ethylene-butene copolymer elastomer, SEPS elastomer, hydrated magnesium silicate, grafted polyethylene, silane coupling agent, antioxidant and processing aid are mixed to obtain a compound; B) feeding the mixed material into a twin-screw extruder, and performing melting, plasticizing, and granulation to obtain a low-temperature resistant polypropylene impact-modified material.

10. An automobile component, characterized in that: The raw materials for its preparation include the low-temperature resistant polypropylene impact-modified material according to any one of claims 1 to 8; The automobile component is a seal or an automobile bumper.

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