Polypropylene composition as well as preparation method and application thereof

Abstract

The invention discloses a polypropylene composition as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The polypropylene composition comprises the following raw material components in parts by weight: 40-70 parts of polypropylene resin; 10 to 50 parts of a flame retardant; 5-30 parts of a fluxing agent; 10-40 parts of a ceramic forming filler; 1-10 parts of a functional filler; the flame retardant comprises a carbon source and an acid source; the ceramic forming filler comprises at least one of wollastonite, sepiolite, olivine, mica powder and montmorillonite; the functional filler comprises at least one of barium phosphate, aluminum hypophosphite, magnesium phosphate, zirconium hydrogen phosphate and calcium phosphate; the weight ratio of the ceramic forming filler to the functional filler is (1-3): 1. The polypropylene composition disclosed by the invention has excellent flame retardant property and mechanical property.

Description

Technical Field

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

[0002] The battery pack separators of traditional new energy vehicles are made of high-temperature resistant alloys, which have drawbacks such as high weight, manufacturing difficulties, and high costs. This prevents lightweighting and increases manufacturing costs. Meanwhile, high-molecular-weight polyolefins, due to their excellent mechanical properties, low density, and excellent insulation properties, have been widely used to replace metal automotive parts. However, their flammability and tendency to drip during combustion limit their application in new energy battery packs. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a polypropylene composition and a preparation method and application thereof. The polypropylene composition of the present invention has excellent flame retardant properties and mechanical properties.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] In a first aspect, the present invention provides a polypropylene composition comprising the following raw material components in parts by weight:

[0006] 40-70 parts of polypropylene resin; 10-50 parts of flame retardant; 5-30 parts of flux; 10-40 parts of porcelain-forming filler; 1-10 parts of functional filler; the flame retardant includes a carbon source and an acid source;

[0007] The ceramic filler includes at least one of wollastonite, sepiolite, olivine, mica powder, and montmorillonite; the functional filler includes at least one of barium phosphate, aluminum hypophosphite, magnesium phosphate, zirconium hydrogen phosphate, and calcium phosphate; the weight ratio of the ceramic filler to the functional filler is (1-3):1.

[0008] The functional filler of the present invention utilizes the heat generated during high-temperature combustion to decompose into metal oxides and phosphorus pentoxide, which can reduce the peak heat release rate. In addition, the metal oxide obtained by decomposition has a porcelain-forming effect, and the phosphorus pentoxide obtained by decomposition has a carbon-forming effect. The two cooperate with each other to achieve a flame-retardant effect of efficient carbonization and porcelainization, which is beneficial to improving the flame retardant properties of the polypropylene composition.

[0009] The flame retardant described in this invention combines a carbon source with an acid source, enabling the PP resin to form a primary carbon barrier at low temperatures, initially isolating oxygen from the resin. Furthermore, under the action of a flux, the ceramic filler undergoes cross-linking at high temperatures, forming pores that further react with the carbon layer to form a hard ceramic layer. Furthermore, the functional filler contributes to enhanced flame retardancy.

[0010] The present invention helps to further improve the flame retardant properties and mechanical properties of the polypropylene composition by controlling the weight ratio of the ceramic filler to the functional filler within the above range.

[0011] The zirconium hydrogen phosphate decomposes at high temperature in the following reaction:

[0012] Zr(HPO4)2→ZrO2+P2O 5+ H2O.

[0013] The decomposition reactions of the barium phosphate, aluminum hypophosphite, magnesium phosphate and calcium phosphate at high temperature are as follows:

[0014] Ba3(PO4)2→3BaO+P2O5.

[0015] 2Al(H2PO4)3→Al2O3+3P2O5+6H2O.

[0016] Mg3(PO4)2→3MgO+P2O5.

[0017] Ca3(PO4)2→3CaO+P2O5.

[0018] Preferably, the wollastonite is fibrous or needle-shaped, with an average particle size of 10-200 μm.

[0019] Preferably, the sepiolite is fibrous, with an average particle size of 5-50 μm.

[0020] Preferably, the olivine is in granular form with an average particle size of 5-100 μm.

[0021] Preferably, the mica powder is in flaky form and has an average particle size of 10-200 μm.

[0022] Preferably, the montmorillonite is in the form of layered nanoparticles with an average particle size of less than 1 μm.

[0023] Preferably, the barium phosphate is in granular form, has an average particle size of 1-10 μm, and a decomposition temperature of 800-1000°C.

[0024] Preferably, the aluminum hypophosphite is in granular form, has an average particle size of 1-5 μm, and a decomposition temperature of 200-350°C.

[0025] Preferably, the magnesium phosphate is spherical or flaky, has an average particle size of 2-20 μm, and a decomposition temperature of 600-800°C.

[0026] Preferably, the zirconium hydrogen phosphate is in granular form, with an average particle size of 1-5 μm or 50-200 nm and a decomposition temperature of 500-900°C.

[0027] Preferably, the calcium phosphate is in granular form, has an average particle size of 1-5 μm, and a decomposition temperature of 700-900°C.

[0028] Preferably, the polypropylene resin comprises at least one of homopolypropylene resin and maleic anhydride grafted PP, wherein the grafting rate of maleic anhydride in the maleic anhydride grafted PP is 0.5-1.5%.

[0029] Preferably, the mass ratio of the carbon source to the acid source is (1-3): (1-3).

[0030] More preferably, the mass ratio of the carbon source to the acid source is in the range of any one or both of 1:1, 1:2, 1:3, 2:1, 2:3, 3:1, 3:2.

[0031] Preferably, the carbon source includes at least one of piperazine pyrophosphate, dipentaerythritol, glycerol zinc, and melamine sodium pyrophosphate.

[0032] Preferably, the acid source includes at least one of ammonium polyphosphate, sodium pyrophosphate, and sodium polyphosphate.

[0033] Preferably, the flux includes at least one of calcium borate, zinc borate, and glass powder.

[0034] More preferably, the glass powder includes at least one of high-melting-point glass powder and low-melting-point glass powder, wherein the melting point of the high-melting-point glass powder is 800-1000°C, and the melting point of the low-melting-point glass powder is 350-600°C.

[0035] Preferably, the polypropylene composition comprises the following raw material components in parts by weight:

[0036] 45-65 parts of polypropylene resin; 15-40 parts of flame retardant; 5-30 parts of flux; 12-30 parts of porcelain-forming filler; 3-8 parts of functional filler.

[0037] Preferably, the polypropylene composition further comprises 1-5 parts by weight of other additives.

[0038] Preferably, the other additives include lubricant, antioxidant, coupling agent, and anti-dripping agent, and the mass ratio of the lubricant, antioxidant, coupling agent, and anti-dripping agent is (1-3): (1-3): (1-3): (1-3), preferably 2:2:2:1.

[0039] Preferably, the lubricant includes at least one of dimethyl silicone oil, benzyl silicone oil, and PE wax.

[0040] Preferably, the antioxidant includes at least one of antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 225, and antioxidant 1098.

[0041] Preferably, the coupling agent includes at least one of KH550, KH560, and KH570.

[0042] Preferably, the anti-drip agent is polytetrafluoroethylene (PTFE).

[0043] In a second aspect, the present invention further provides a method for preparing a polypropylene composition, comprising the following steps:

[0044] The raw material components are mixed evenly and then added into a twin-screw extruder, and a polypropylene composition is obtained after granulation and cooling.

[0045] Preferably, the temperature of the extruder is 190-220° C., and the screw speed is 100-500 rpm.

[0046] In a third aspect, the present invention further provides an application of a polypropylene composition in automotive parts. Specifically, the polypropylene composition of the present invention is suitable for automotive battery housings.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The raw material components of the polypropylene composition of the present invention can pass the 5VA test on a 2.0 mm square plate without the addition of inorganic glass fiber. Furthermore, the polypropylene composition of the present invention does not contain organic brominated flame retardants, generates very little harmful gas during processing, and produces low and non-toxic smoke from ablation.

[0049] (2) The present invention uses a functional filler with unique decomposition properties, which can not only provide metal oxides but also provide phosphorus pentoxide as an acid source when decomposed at high temperature, thereby improving the flame retardant properties of the polypropylene composition. DETAILED DESCRIPTION

[0050] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments, but the protection scope and implementation methods of the present invention are not limited thereto.

[0051] Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0052] Examples 1-14

[0053] The embodiments of the polypropylene composition and the preparation method thereof of the present invention, the raw material components of the polypropylene composition are shown in Table 1.

[0054] The preparation method of the polypropylene composition comprises the following steps:

[0055] The raw material components were mixed uniformly and then added to a twin-screw extruder, granulated, and cooled to obtain a polypropylene composition. The extruder temperature was: zone 1 160°C, zone 2 180°C, zone 3 190°C, zone 4 190°C, zone 5 190°C, zone 6 190°C, die head 200°C, and the screw speed was 150 rpm.

[0056] Comparative Examples 1-8

[0057] The only difference between the comparative examples and the examples is the type and ratio of the raw material components, as shown in Table 2.

[0058] Among the raw material components described in each embodiment and comparative example:

[0059] The polypropylene resin 1 is a homopolymer polypropylene resin: the manufacturer is ExxonMobil, the model is PP1304E5;

[0060] The polypropylene resin 2 is maleic anhydride grafted PP: the manufacturer is Coase, and the model is B1.

[0061] The flame retardant 1 comprises dipentaerythritol and ammonium polyphosphate, and the weight ratio of the two is 1:1;

[0062] The flame retardant 2 includes dipentaerythritol and sodium pyrophosphate, and the weight ratio of the two is 1:3;

[0063] The flame retardant 3 includes melamine sodium pyrophosphate and sodium pyrophosphate, and the weight ratio of the two is 3:1;

[0064] The flame retardant 4 is ammonium polyphosphate;

[0065] The flame retardant 5 is dipentaerythritol.

[0066] Among the flame retardants 1-5, the manufacturer of dipentaerythritol is Jiangsu Ruiyang Chemical Co., Ltd.; the manufacturer of ammonium polyphosphate is Shifang Changfeng Chemical Co., Ltd.; the manufacturers of melamine sodium pyrophosphate and sodium pyrophosphate are both Suzhou Dongxing Heng Chemical Co., Ltd.

[0067] The flux 1 is calcium borate, manufactured by Wuhan Jiyesheng Chemical Co., Ltd.

[0068] The flux 2 is zinc borate, and the manufacturer is Shandong Wuwei Flame Retardant Technology Co., Ltd.

[0069] The ceramic filler 1 is olivine with an average particle size of 40 nm; the manufacturer is Yichang Fuquan Forsterite Co., Ltd.

[0070] The porcelain-forming filler 2 is wollastonite with an average particle size of 100 μm; the manufacturer is Guangde County Zhengyuan Wollastonite Powder Co., Ltd.

[0071] The ceramic filler 3 is mica powder with an average particle size of 50 μm; the manufacturer is Foshan Bozhen Chemical Co., Ltd.

[0072] The porcelain-forming filler 4 is zeolite powder with an average particle size of 1 μm; the manufacturer is Dehui Zeolite Powder Factory.

[0073] The functional filler 1 is barium phosphate with an average particle size of 5 μm; the manufacturer is Anaiji Chemical.

[0074] The functional filler 2 is aluminum hypophosphite with an average particle size of 2 μm; the manufacturer is Hubei Yiruicheng New Material Technology Co., Ltd.

[0075] The functional filler 3 is magnesium phosphate with an average particle size of 5 μm; the manufacturer is Anaiji Chemical.

[0076] The functional filler 4 is zirconium hydrogen phosphate with an average particle size of 2 μm; the manufacturer is Fujian Ruisen New Materials Co., Ltd.

[0077] The above fillers are all obtained by screening.

[0078] The other additives include a lubricant, an antioxidant, a coupling agent, and an anti-dripping agent, and the mass ratio of the lubricant, antioxidant, coupling agent, and anti-dripping agent is 2:2:2:1.

[0079] The lubricant is dimethyl silicone oil, and the manufacturer is Jiangmen Shengpeng Chemical Industry Co., Ltd.

[0080] The antioxidant is antioxidant 1010, and the manufacturer is Linyi Sanfeng Chemical Co., Ltd.

[0081] The coupling agent is KH550, and the manufacturer is Anaiji Chemical.

[0082] The anti-dripping agent is polytetrafluoroethylene, and the manufacturer is Shandong Senrong New Materials Co., Ltd.

[0083] Unless otherwise specified, the components and raw materials used in the examples and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0084] Table 1

[0085]

[0086]

[0087]

[0088] Table 2

[0089]

[0090] In order to verify the performance of the polypropylene composition of the present invention, the polypropylene composition prepared in each embodiment and comparative example was injection molded into a specimen to test the following properties. The thickness of the specimen was 1.5 mm.

[0091] Performance testing method:

[0092] 1. Notched impact strength: tested in accordance with GB / T 1843-2008 test standard, with an impact energy of 2.5J.

[0093] 2. Tensile strength: Tested in accordance with GB / T 228.1-2021 test standard.

[0094] 3. Flame retardant grade: 500W flame test method is GB / T 5169.17-2017, and the test square plate thickness is 2mm.

[0095] 4. Bending performance: Tested in accordance with GB / T 9341-2000 test standard.

[0096] The performance parameters obtained from the above tests are shown in Table 3.

[0097] Table 3

[0098]

[0099] As shown in Table 1, the polypropylene composition of the present invention has excellent flame retardant properties and mechanical properties. By comparing Comparative Examples 1-3 with Example 1, it can be seen that no porcelain-forming filler was added in Comparative Example 1, no functional filler was added in Comparative Example 2, and no flux was added in Comparative Example 3. The flame retardant properties of the polypropylene composition were not as good as those of Example 1, indicating that the addition of porcelain-forming fillers, functional fillers, fluxes and flame retardants can help improve the flame retardant properties of the polypropylene composition. In Comparative Example 4, zeolite powder of equal mass was used to replace olivine, and the polypropylene composition failed to pass the 5VA test, and the mechanical properties of the polypropylene composition were reduced, indicating that not any combination of porcelain-forming fillers and functional fillers can make the polypropylene composition have excellent flame retardant properties and mechanical properties at the same time.

[0100] By comparing Comparative Examples 5-6 with Example 1, it can be seen that if the weight ratio of the ceramic filler to the functional filler is too low or too high, the polypropylene composition cannot pass the 5VA test, and the mechanical properties of the polypropylene composition will also be affected. This shows that the present invention is beneficial to improving the flame retardant properties and mechanical properties of the polypropylene composition by controlling the weight ratio of the ceramic filler to the functional filler to (1-3):1.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composition, characterized in that The raw material components include the following parts by weight: 40-70 parts of polypropylene resin; 10-50 parts of flame retardant; 5-30 parts of flux; 10-40 parts of porcelain-forming filler; 1-10 parts of functional filler; the flame retardant includes a carbon source and an acid source; The ceramic filler includes at least one of wollastonite, sepiolite, olivine, mica powder, and montmorillonite; the functional filler includes at least one of barium phosphate, aluminum hypophosphite, magnesium phosphate, zirconium hydrogen phosphate, and calcium phosphate; the weight ratio of the ceramic filler to the functional filler is (1-3):

1.

2. The polypropylene composition according to claim 1, wherein The polypropylene resin includes at least one of homopolymer polypropylene resin and maleic anhydride grafted PP.

3. The polypropylene composition according to claim 1, wherein The mass ratio of the carbon source to the acid source is (1-3): (1-3).

4. The polypropylene composition according to claim 1, wherein The carbon source includes at least one of piperazine pyrophosphate, dipentaerythritol, glycerol zinc, and melamine sodium pyrophosphate; And / or, the acid source includes at least one of ammonium polyphosphate, sodium pyrophosphate, and sodium polyphosphate.

5. The polypropylene composition according to claim 1, wherein The average particle size of the wollastonite is 10-200 μm; and / or, the average particle size of the sepiolite is 5-50 μm; and / or, the average particle size of the olivine is 5-100 μm; and / or, the average particle size of the mica powder is 10-200 μm; And / or, the average particle size of the montmorillonite is less than 1 μm.

6. The polypropylene composition according to claim 1, wherein The average particle size of the barium phosphate is 1-10 μm; And / or, the average particle size of the aluminum hypophosphite is 1-5 μm; and / or, the average particle size of the magnesium phosphate is 2-20 μm; and / or, the average particle size of the zirconium hydrogen phosphate is 1-5 μm or 50-200 nm; And / or, the average particle size of the calcium phosphate is 1-5 μm.

7. The polypropylene composition according to claim 1, wherein The flux includes at least one of calcium borate, zinc borate, and glass powder.

8. The polypropylene composition according to claim 1, wherein The polypropylene composition further comprises 1-5 parts by weight of other additives.

9. A method for preparing the polypropylene composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw material components are mixed evenly and then added into a twin-screw extruder, and a polypropylene composition is obtained after granulation and cooling.

10. Use of the polypropylene composition according to any one of claims 1 to 8 in automobile parts.

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