Polypropylene composition as well as preparation method and application thereof

Abstract

The invention relates to a polypropylene composition as well as a preparation method and application thereof, and belongs to the technical field of compositions of high-molecular compounds. The polypropylene composition comprises the following components in parts by weight: 30-75 parts of polypropylene resin, 20-30 parts of a halogen-free flame retardant, 3-8 parts of an elastomer graft, 5-30 parts of metal powder, 0.1-1 part of a metal deactivator and 0.1-1 part of an interface improver, the elastomer graft is polyolefin elastomer grafted maleic anhydride and / or glycidyl methacrylate; the metal powder is a metal elementary substance and / or a metal oxide with the retention particle size D50 larger than or equal to 15 microns; the interface improver is a mixture of at least one of stearate and stearic acid and hyperbranched polyester. The polypropylene composition has the advantages of excellent ablation resistance, excellent flame retardant stability and good mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular compound composition, in particular to a polypropylene composition and a preparation method and application thereof. BACKGROUND

[0002] Polypropylene (PP) is widely used in battery shell, body shield, wire harness support and other electric bicycle parts due to its light weight, low cost, easy processing and other advantages, but lithium batteries in electric bicycles are prone to thermal runaway and cause fire under conditions such as overcharging, short circuit and heavy impact, and polypropylene is flammable and easy to melt and drip at high temperature, which cannot meet the safety requirements of electric bicycles. At present, halogen-free flame retardants such as intumescent or metal oxides are mainly used to improve the flame retardant properties of polypropylene materials, and polytetrafluoroethylene powder is used to improve the anti-dripping performance of polypropylene materials, or glass fibers, carbon fibers and other materials are used to improve the ablation resistance of polypropylene materials; at the same time, it is often necessary to add more flame retardant components in polypropylene materials to effectively improve their flame retardant properties, but this will result in poor mechanical properties of polypropylene materials, and the above flame-retardant modification methods are difficult to effectively improve the flame-retardant stability of polypropylene materials. In addition, the introduction of a large amount of inorganic fibers, metals and flame-retardant systems, and complex interface defects make oxygen / water more easily penetrate, causing thermal oxidative degradation or photoaging degradation of the material, affecting its long-term service performance. SUMMARY

[0003] The present application aims to overcome the deficiencies of the prior art and provide a polypropylene composition and a preparation method and application thereof.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: In a first aspect, the present application provides a polypropylene composition, comprising the following components by weight fraction: polypropylene resin 30-75 parts, halogen-free flame retardant 20-30 parts, elastomer grafting 3-8 parts, metal powder 5-30 parts, metal passivator 0.1-1 part, and interface modifier 0.1-1 part. The elastomer grafting is polyolefin elastomer grafting maleic anhydride and / or glycidyl methacrylate; the metal powder is metal element and / or metal oxide with a particle size D 50 ≥ 15 μm; The interface modifier is a mixture of at least one of stearate and stearic acid and hyperbranched polyester.

[0005] The present application takes polypropylene resin as the base resin, matches with halogen-free flame retardant, and combines with metal powder of specific particle size, specific elastomer graft, specific interface modifier and metal passivator. The halogen-free flame retardant and the metal powder synergistically improve the flame retardant property of the polypropylene composition, and the metal powder dispersed in the polypropylene resin matrix can form a local heat conduction network to quickly disperse the surface heat during combustion, can embed the carbon layer generated by the combustion of the polypropylene resin to improve the strength of the carbon layer, and can fill the pores of the carbon layer to reduce crack propagation, thereby improving the flame retardant property and ablation resistance of the polypropylene composition.

[0006] The elastomer graft can promote the dispersion of the halogen-free flame retardant and the metal powder and improve the interface bonding property of the two with the polypropylene resin, thereby making the polypropylene composition have higher mechanical property; the stearate or stearic acid in the interface modifier can preliminarily coat the halogen-free flame retardant and the metal powder during melt blending, and the hyperbranched resin further coats the halogen-free flame retardant and the metal powder through the multi-functional groups, thereby promoting the highly uniform dispersion of the halogen-free flame retardant and the metal powder in the base resin, so as to build a continuous, dense and high-strength solid carbon layer during combustion; the metal passivator can form a stable complex layer by chelation or coordination reaction with the surface of the metal powder, which can not only slow down the aging damage, but also promote the improvement of the interface bonding property of the metal powder and the base resin, thereby making the carbon layer not easy to be pulverized, cracked or detached during expansion and bearing external heat flow impact, thereby improving the flame retardant stability of the polypropylene composition.

[0007] In some embodiments, the weight fraction of the polypropylene resin in the polypropylene composition can be specifically but not limited to 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, 62 parts, 64 parts, 66 parts, 68 parts, 70 parts, 73 parts or 75 parts, or within a range formed by any two of the above values.

[0008] In some embodiments, the weight fraction of the halogen-free flame retardant in the polypropylene composition can be specifically but not limited to 20 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts or 30 parts, or within a range formed by any two of the above values.

[0009] In some embodiments, the weight fraction of the elastomer graft in the polypropylene composition can be specifically but not limited to 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts or 8 parts, or within a range formed by any two of the above values.

[0010] In some embodiments, the weight fraction of the metal powder in the polypropylene composition can be, but is not limited to, 5 parts, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or 30 parts, or within a range between any two of the above values.

[0011] In some embodiments, the weight fraction of the metal passivator in the polypropylene composition can be, but is not limited to, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, or 1 parts, or within a range between any two of the above values.

[0012] In some embodiments, the weight fraction of the interfacial modifier in the polypropylene composition can be, but is not limited to, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, or 1 parts, or within a range between any two of the above values.

[0013] The polypropylene resin in the polypropylene composition is a matrix resin, and the mass percentage of the polypropylene resin is ≥ 28%. The morphology of the metal powder is spherical, spherical-like, or rod-like, and the mass percentage of the metal powder in the polypropylene composition is 5% to 30%. If the reserved particle size D 50 If the reserved particle size D

[0014] The reserved particle size D 50 is the reserved particle size D 50 of the metal powder in the polypropylene composition obtained by melt extrusion of the components.

[0015] In some embodiments, the polyolefin elastomer in the elastomer grafting product can include, but is not limited to, at least one of ethylene-octene copolymer, ethylene-hexene copolymer, ethylene-butene copolymer.

[0016] In some embodiments, the metal passivator contains an amide or hydrazide structure and a hindered phenol group, for example, can include, but is not limited to, at least one of 2,2-oxamido-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, bis(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl).

[0017] As a preferred embodiment of the polypropylene composition of the present application, the polypropylene resin in the polypropylene composition is 40-60 parts by weight, the halogen-free flame retardant is 24-27 parts by weight, and the metal powder is 12-25 parts by weight.

[0018] As a preferred embodiment of the polypropylene composition of the present application, the retained particle size D 50 of the metal powder is 20-100 μm, for example, can be 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm, or within a range between any two of the above values. It has been found that the retained particle size D 50 of the metal powder within the above range not only better promotes the formation of a continuous network structure, but also forms a more stable, denser and stronger intumescent carbon layer with the decomposition products of the halogen-free flame retardant, effectively avoids the local rapid heating caused by the agglomeration of the metal powder to form a "wick effect", and further better improves the flame retardant properties of the polypropylene composition.

[0019] As a preferred embodiment of the polypropylene composition of the present application, the interfacial modifier is a mixture of hyperbranched polyester, stearate and stearic acid, and the mass ratio of the hyperbranched polyester, stearate and stearic acid is (0.5-1.5):(0.5-1.5):(0.5-1.5).

[0020] The hyperbranched polyester (HBP) has a three-dimensional dendritic structure and contains functional groups such as hydroxyl and carboxyl groups. After being combined with stearate and stearic acid, it can effectively promote the uniform dispersion of the halogen-free flame retardant and the metal powder, and also can to some extent assist the halogen-free flame retardant to form a dense carbon layer, and further better improve the flame retardant properties of the polypropylene composition.

[0021] In some embodiments, the hyperbranched polyester can be but is not limited to 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts or 1.5 parts by weight, or within a range between any two of the above values.

[0022] In some embodiments, the stearate can be but is not limited to 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts or 1.5 parts by weight, or within a range between any two of the above values.

[0023] In some embodiments, the stearic acid can be, but is not limited to, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, or 1.5 parts, or within a range between any two of the above-mentioned values, by weight.

[0024] In some embodiments, the hyperbranched polyester comprises, but is not limited to, at least one of a carboxyl-terminated hyperbranched polyester, a hydroxyl-terminated hyperbranched polyester.

[0025] In some embodiments, the hyperbranched polyester has a number average molecular weight of 800 g / mol to 6500 g / mol, for example, can be, but is not limited to, 800 g / mol, 1000 g / mol, 1500 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, 5000 g / mol, 5500 g / mol, 6000 g / mol, or 6500 g / mol, or within a range between any two of the above-mentioned values.

[0026] In some embodiments, the hyperbranched polyester has a number of carboxyl groups per mole or a number of hydroxyl groups per mole of 5 to 25, for example, can be, but is not limited to, 5, 6, 8, 10, 12, 14, 16, 18, 20, 22, or 25, or within a range between any two of the above-mentioned values. The number of carboxyl groups or hydroxyl groups per mole refers to the number of terminal carboxyl groups or hydroxyl groups on each mole of polymer molecules.

[0027] As a preferred embodiment of the polypropylene composition of the present application, the polypropylene resin has a melt mass-flow rate of 5 g / 10 min to 100 g / 10 min at 230 °C, 2.16 kg (using the ISO 1133-1:2022 standard), for example, can be 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, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 55 g / 10 min, 60 g / 10 min, 65 g / 10 min, 70 g / 10 min, 75 g / 10 min, 80 g / 10 min, 85 g / 10 min, 90 g / 10 min, 95 g / 10 min, or 100 g / 10 min, or within a range between any two of the above-mentioned values.

[0028] As a preferred embodiment of the polypropylene composition of the present application, the polypropylene composition satisfies at least one of the following conditions: (1) the halogen-free flame retardant comprises at least one of ammonium polyphosphate, piperazine pyrophosphate, melamine polyphosphate, melamine pyrophosphate, triazine charring agent, melamine cyanurate; (2) the material of the metal powder is at least one of aluminum and its oxides, iron and its oxides, and steel; (3) the stearate comprises at least one of dipentaerythritol stearate and pentaerythritol distearate.

[0029] As a preferred embodiment of the polypropylene composition of the present application, 0.1-3 parts by weight of a processing aid is further included in the components of the polypropylene composition. The processing aid can be, but is not limited to, at least one of an antioxidant, a weathering agent, a lubricant, and a colorant.

[0030] In some embodiments, the antioxidant is 0.1-0.3 parts by weight, which includes but is not limited to hindered phenolic antioxidants, phosphite antioxidants, sulfide antioxidants, and the like.

[0031] In some embodiments, the weathering agent is 0.1-0.3 parts by weight, which includes but is not limited to benzotriazoles, benzophenones, triazines, hindered amines, and the like.

[0032] In some embodiments, the lubricant is 0.1-0.3 parts by weight, which includes but is not limited to stearic acid lubricants, amide lubricants, organic wax lubricants, and the like.

[0033] In a second aspect, the present application provides a preparation method of the above-mentioned polypropylene composition, comprising the following steps: uniformly mixing the components and melt extruding to obtain the polypropylene composition.

[0034] Specifically, the melt extruding in the above-mentioned preparation method can be carried out by using a twin-screw extruder, the temperature of the melt extruding is 180-210°C, and the screw rotation speed of the twin-screw extruder is 400-600 rpm.

[0035] In a third aspect, the present application provides an application of the above-mentioned polypropylene composition in preparing household products, electronic components, household equipment, gardening equipment, medical technical equipment, motor vehicle parts or body parts, and electric bicycles.

[0036] In a fourth aspect, the present application provides a part of an electric bicycle, which is made of the above-mentioned polypropylene composition.

[0037] Exemplarily, the parts of the electric bicycle include but are not limited to a frame, a seat tube, a pedal, a handlebar, a mudguard, a connector, an insulating part, a shock absorber, a suspension part, a shell, a cowling, a pedal decoration strip, a battery shell, a wire harness support, and the like.

[0038] Compared with the prior art, the present application has the following beneficial effects: The present application uses polypropylene resin as the base resin, and is combined with halogen-free flame retardant, metal powder of specific particle size, specific elastomer graft, liquid hydrocarbon, specific interface modifier and metal passivator. The halogen-free flame retardant and the metal powder synergistically improve the flame retardant property of the polypropylene composition. The metal powder dispersed in the polypropylene resin matrix can form a local heat conduction network to quickly disperse the surface heat during combustion, and can also embed the carbon layer generated by the combustion of the polypropylene resin to improve the strength of the carbon layer and fill the pores of the carbon layer to reduce crack propagation, thereby improving the flame retardant property and ablation resistance of the polypropylene composition.

[0039] The elastomer graft can promote the dispersion of the halogen-free flame retardant and the metal powder and improve the interfacial bonding property of the two with the polypropylene resin, thereby making the polypropylene composition have higher mechanical properties. The stearate or stearic acid in the interface modifier can preliminarily coat the halogen-free flame retardant and the metal powder during melt blending, and the hyperbranched resin can further coat the halogen-free flame retardant and the metal powder through its multi-functional groups, thereby promoting the highly uniform dispersion of the halogen-free flame retardant and the metal powder in the base resin, so as to build a continuous, dense and high-strength solid carbon layer during combustion. The metal passivator can form a stable complex layer by chelation or coordination reaction with the surface of the metal powder, which can not only slow down the aging damage, but also promote the improvement of the interfacial bonding property of the metal powder and the base resin, thereby making the carbon layer not easy to powder, crack or fall off when swelling and bearing external heat flow impact, thereby improving the flame retardant stability of the polypropylene composition. DETAILED DESCRIPTION

[0040] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples.

[0041] Unless otherwise specified, other materials, reagents, etc. used in the examples and comparative examples can be obtained from commercial channels.

[0042] 1. Raw material reagents 1) Polypropylene resin Polypropylene resin 1, melt mass flow rate 12.3 g / 10 min, brand HP500N, manufacturer Daqing Refining and Chemical Company of China Petroleum; polypropylene resin 2, melt mass flow rate 8.5 g / 10 min, brand EP300M, manufacturer China CNOOC Petroleum & Chemicals Limited; Polypropylene resin 3, melt mass flow rate 49 g / 10 min, brand BX3900, manufacturer Aksel New International Business (Shanghai) Co., Ltd.

[0043] 2) Halogen-free flame retardant Halogen-free flame retardant 1 is a nitrogen-phosphorus halogen-free flame retardant, brand FP-2200, manufacturer Aidi Ke. Halogen-free flame retardant 2 is nitrogen-phosphorus halogen-free flame retardant, brand JLS-PNA260, manufacturer Jelts.

[0044] 3) Elastomer graft, polyolefin elastomer and polypropylene graft maleic anhydride Elastomer graft 1 (POE-g-MAH), brand FUSABON DN 493, manufacturer DuPont; Elastomer graft 2 (POE-g-GMA), brand SOG-03, manufacturer Dow; Polyolefin elastomer (POE), brand POE 8173, manufacturer Dow; Polypropylene graft maleic anhydride (PP-g-MAH), brand PC-1, manufacturer Foshan Nanhai Baimen High Polymer New Material Co., Ltd.

[0045] 4) Metal powder Metal powder 1 is iron powder, particle size D 50 25 μm, commercially available; Metal powder 2 is iron powder, particle size D 50 45 μm, commercially available; Metal powder 3 is iron powder, particle size D 50 75 μm, commercially available; Metal powder 4 is iron powder, particle size D 50 7 μm, commercially available; Glass fiber, brand ECS13-05-508A, manufacturer Jushi.

[0046] 5) Metal deactivator Metal deactivator 1 is 2,2-oxamide-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)] propionate, brand SONOX 1027, manufacturer Sanfeng; Metal deactivator 2 is bis(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl), brand RIANOX MD-1024, manufacturer Li'anlong.

[0047] 6) Interface modifier Interface modifier 1 is composed of hyperbranched polyester, stearate and stearic acid in a mass ratio of 1:1:1; Interface modifier 2 is composed of hyperbranched polyester, stearate and stearic acid in a mass ratio of 1.5:0.5:0.5; Interface modifier 3 is composed of hyperbranched polyester, stearate and stearic acid in a mass ratio of 0.5:1.5:1.5; Interface modifier 4 is composed of hyperbranched polyester and stearate in a mass ratio of 1:1; Interface modifier 5 is composed of hyperbranched polyester and stearic acid in a mass ratio of 1:1; Interface modifier 6 is hyperbranched polyester; Interface modifier 7 is composed of stearate and stearic acid with a mass ratio of 1:1; The above hyperbranched polyester is the same kind, its brand is HYPER C100, and the manufacturer is Wuhan Hyperbranched Resin; the stearate is dipentaerythritol stearate, which is commercially available; and the stearic acid is commercially available.

[0048] 7) Processing aid The antioxidant is composed of antioxidant 1010 (commercially available) and antioxidant 168 (commercially available) with a mass ratio of 1:2.

[0049] 2) Preparation method of the polypropylene composition According to the formula, the polypropylene resin, the halogen-free flame retardant, the elastomer graft (or polyolefin elastomer or polypropylene graft maleic anhydride), the metal powder (or glass fiber), the metal passivator, the interface modifier and the processing aid are mixed and then fed into a twin-screw extruder for melt extrusion to obtain the polypropylene composition. The temperature range of the twin-screw extruder is 180-210°C, and the rotation speed of the screw is 450 rpm.

[0050] 3) Each embodiment and comparative example Table 1: Weight fraction of each component of the polypropylene composition in each embodiment Example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Polypropylene resin 1 50 / / 50 50 50 50 50 50 50 50 50 30 73 40 60 Polypropylene resin 2 / 50 / / / / / / / / / / / / / / Polypropylene resin 3 / / 50 / / / / / / / / / / / / / Halogen-free flame retardant 1 24 24 24 / 24 24 24 24 24 24 24 24 30 22 27 24 Halogen-free flame retardant 2 / / / 24 / / / / / / / / / / / / Elastomer graft 1 5 5 5 5 / 5 5 5 5 5 5 5 8 3 5 5 Elastomer graft 2 / / / / 5 / / / / / / / / / / / Metal powder 1 18 18 18 18 18 / / 18 18 18 18 18 30 5 25 12 Metal powder 2 / / / / / 18 / / / / / / / / / / Metal powder 3 / / / / / / 18 / / / / / / / / / Metal deactivator 1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 / 0.5 0.5 0.5 0.5 1 0.1 0.5 0.5 Metal deactivator 2 / / / / / / / 0.5 / / / / / / / / Interface improver 1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 / / / / 1 0.1 0.5 0.5 Interface improver 2 / / / / / / / / 0.5 / / / / / / / Interface improver 3 / / / / / / / / / 0.5 / / / / / / Interface improver 4 / / / / / / / / / / 0.5 / / / / / Interface improver 5 / / / / / / / / / / / 0.5 / / / / Processing aid 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 1 / 0.3 0.3 Table 2: Weight fraction of each component of the polypropylene composition in each comparative example Comparative example 1 2 3 4 5 6 Polypropylene resin 1 50 50 50 50 50 50 Halogen-free flame retardant 1 24 24 24 24 24 24 Elastomer graft 1 / / 5 5 5 5 POE 5 / / / / / PP-g-MAH / 5 / / / / Metal powder 1 18 18 / / 18 18 Metal powder 4 / / 18 / / / Glass fiber / / / 18 / / Metal deactivator 1 0.5 0.5 0.5 0.5 0.5 0.5 Interface improver 1 0.5 0.5 0.5 0.5 / / Interface improver 6 / / / / 0.5 / Interface improver 7 / / / / / 0.5 Processing aid 0.3 0.3 0.3 0.3 0.3 0.3 4) Performance test 1) Notched impact strength: the polypropylene composition in each embodiment and comparative example is tested for notched impact strength according to the ISO 180-2019 standard, and the notch type is A type; 2) Ablation resistance: the polypropylene composition in each embodiment and comparative example is injection molded into a sample plate with a size of 100mm x 100mm x 3mm, then a butane flame with a temperature of 1200°C is vertically fired on the sample plate for 600 seconds, and if the sample plate can still sustain itself, the test is passed, otherwise it is failed; 3) Flame retardant performance before and after aging: the polypropylene composition in each embodiment and comparative example is tested for UL94 vertical burning, and the aging experiment is performed according to the ISO 4892-2 standard for 500h of xenon lamp aging.

[0051] Table 3: Performance of the polypropylene composition in each embodiment and comparative example According to the data in Table 3, the notched impact strength of the polypropylene composition in each of embodiments 1-16 is ≥6.3kJ / m 2, and none of them is burnt through by 1200℃ butane flame vertical impact for 600 seconds, and the flame retardant level after aging under xenon lamp for 500h can still reach V-0, indicating that the polypropylene composition of the application has excellent ablation resistance, flame retardant stability and good mechanical properties.

[0052] Meanwhile, according to the example 1, the comparative example 1 and the comparative example 2, it can be seen that when POE or PP-g-MAH is used instead of the elastomer grafting product combined with other components, it is difficult to effectively improve the mechanical properties of the polypropylene composition; according to the comparative example 3 and the comparative example 4, it can be found that if the particle size of the metal powder is too small or the glass fiber is used instead of the metal powder, the ablation resistance of the polypropylene composition will be poor, and the flame retardant performance will also be deteriorated; according to the comparative example 5 and the comparative example 6, it can be found that when the hyperbranched resin is used alone as the interface modifier, or the stearate and stearic acid are used as the interface modifier, it is difficult to effectively improve the flame retardant stability of the polypropylene composition.

[0053] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the application and not to limit the protection scope of the application. Although the application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the application.

Claims

1. A polypropylene composition, characterized in that, By weight, it includes the following components: 30-75 parts polypropylene resin, 20-30 parts halogen-free flame retardant, 3-8 parts elastomer graft, 5-30 parts metal powder, 0.1-1 part metal passivator, and 0.1-1 part interface improver; The elastomer graft is a polyolefin elastomer grafted with maleic anhydride and / or glycidyl methacrylate; the metal powder retains a particle size D. 50 Metallic elements and / or metal oxides with a diameter of ≥15 μm; The interface modifier is a mixture of at least one of stearate and stearic acid with hyperbranched polyester.

2. The polypropylene composition according to claim 1, characterized in that, The polypropylene composition comprises 40-60 parts by weight of polypropylene resin, 24-27 parts by weight of halogen-free flame retardant, and 12-25 parts by weight of metal powder.

3. The polypropylene composition according to claim 1, characterized in that, The retained particle size D of the metal powder 50 The range is from 20μm to 100μm.

4. The polypropylene composition according to claim 1, characterized in that, The interface modifier is a mixture of hyperbranched polyester, stearate and stearic acid, wherein the mass ratio of hyperbranched polyester, stearate and stearic acid is (0.5-1.5):(0.5-1.5):(0.5-1.5).

5. The polypropylene composition according to claim 1, characterized in that, The melt flow rate of the polypropylene resin at 230°C and 2.16 kg is 5 g / 10 min to 100 g / 10 min.

6. The polypropylene composition according to claim 1, characterized in that, The polypropylene composition satisfies at least one of the following conditions: (1) The halogen-free flame retardant includes at least one of ammonium polyphosphate, piperazine pyrophosphate, melamine polyphosphate, melamine pyrophosphate, triazine charring agent, and melamine cyanurate; (2) The metal powder is made of at least one of aluminum and its oxides, iron and its oxides, and steel; (3) The stearate includes at least one of pentaerythritol stearate and pentaerythritol distearate.

7. The polypropylene composition according to claim 1, characterized in that, The polypropylene composition further includes 0.1 to 3 parts by weight of processing aids.

8. A method for preparing the polypropylene composition according to any one of claims 1 to 7, characterized in that, Includes the following steps: The components are mixed evenly and melt-extruded to obtain a polypropylene composition.

9. The use of the polypropylene composition according to any one of claims 1 to 7 in the preparation of household goods, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle parts or body parts, and electric bicycles.

10. A component of an electric bicycle, characterized in that, Made from the polypropylene composition according to any one of claims 1 to 7.

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