Polypropylene composition, process for its preparation and use thereof

Abstract

The application discloses a kind of polypropylene composition and its preparation method and application, it is related to the technical field of polymer materials.The polypropylene composition includes the following weight parts of raw material components: polypropylene resin 40-70 parts;Flame retardant 10-50 parts;Fluxing agent 5-30 parts;Pore-forming filler 10-40 parts;Functional filler 1-10 parts;The flame retardant includes carbon source and acid source;The pore-forming filler includes at least one of wollastonite, sepiolite, olivine, mica powder, montmorillonite;The functional filler includes at least one of barium phosphate, aluminium hypophosphite, magnesium phosphate, zirconium hydrogen phosphate, calcium phosphate;The weight ratio of pore-forming filler and functional filler is (1-3) : 1.The polypropylene composition has excellent flame retardant performance and mechanical properties.

Description

TECHNICAL FIELD

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

[0002] The traditional battery pack separator of new energy vehicles is composed of high-temperature-resistant alloy, which has the disadvantages of high weight, difficult manufacturing, high cost, etc., resulting in problems such as inability to lightweight the vehicle and high manufacturing cost. At the same time, high molecular polyolefin has been widely used in the replacement of automobile metal parts due to its good mechanical properties, low density, good insulation, etc. However, due to the flammability and burning dripping defects of high molecular polyolefin, its application range in new energy battery packs is limited. SUMMARY

[0003] The present application relates to the technical field of high polymer materials, and in particular to a polypropylene composition, a preparation method and application thereof.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

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

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

[0007] The porcelain-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 porcelain-forming filler and the functional filler is (1-3):1.

[0008] The functional filler generates metal oxides and phosphorus pentoxide by heat decomposition during high-temperature combustion, which can reduce the peak heat release rate. The metal oxides generated by decomposition have a porcelain-forming effect, and the phosphorus pentoxide generated by decomposition has a carbon-forming effect. The two cooperate with each other to achieve efficient carbon-forming and porcelain-forming flame retardation, which is beneficial to improve the flame retardant performance of the polypropylene composition.

[0009] The flame retardant is compounded by the carbon source and the acid source, so that the PP resin forms a first carbon layer barrier at low temperature, preliminarily isolating oxygen from the resin body. And under the action of the fluxing agent, the porcelain-forming filler is crosslinked to form pores at high temperature, and further reacts with the carbon layer to form a hard ceramic layer, and obtains higher flame retardant performance under the action of the functional filler.

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

[0011] The decomposition reaction of the zirconium hydrogen phosphate at high temperature is as follows:

[0012] Zr(HPO4)2→ZrO2+P2O5. 5+ H2O.

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

[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 acicular 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 particulate with an average particle size of 5-100 μm.

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

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

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

[0024] Preferably, the aluminum hypophosphite is particulate with 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 with an average particle size of 2-20 μm and a decomposition temperature of 600-800 °C.

[0026] Preferably, the zirconium hydrogen phosphate is particulate 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 the form of particles with 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 homopolymer polypropylene 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 and the acid source is (1-3):(1-3).

[0030] More preferably, the mass ratio of the carbon source and the acid source is any one of 1:1, 1:2, 1:3, 2:1, 2:3, 3:1, 3:2 or a range value of two of them.

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

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

[0033] Preferably, the fluxing agent comprises at least one of calcium borate, zinc borate, glass powder.

[0034] More preferably, the glass powder comprises 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 weight parts of raw material components:

[0036] Polypropylene resin 45-65 parts; flame retardant 15-40 parts; fluxing agent 5-30 parts; porcelain-forming filler 12-30 parts; functional filler 3-8 parts.

[0037] Preferably, the polypropylene composition further comprises other auxiliary agents in a weight of 1-5 parts.

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

[0039] Preferably, the lubricant comprises at least one of dimethyl silicone oil, phenyl silicone oil, PE wax.

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

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

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

[0043] In a second aspect, the present application further provides a preparation method of the polypropylene composition, comprising the following steps:

[0044] After the raw material components are uniformly mixed, they are added into a twin-screw extruder, and after granulation and cooling, the polypropylene composition is obtained.

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

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

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

[0048] (1) The polypropylene composition of the present application can meet the 2.0mm square board 5VA test without adding inorganic glass fibers. Moreover, the polypropylene composition of the present application does not contain organic bromine-based flame retardants, and the harmful gas generated during processing is very little, the smoke generated by ablation is low and non-toxic and harmless.

[0049] (2) The functional filler with unique decomposition is used in the present application, which not only provides metal oxides at high temperature, but also provides phosphorus pentoxide as an acid source, so that the flame retardant performance of the polypropylene composition is improved. DETAILED DESCRIPTION

[0050] 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, but the protection scope and implementation mode of the present application are not limited thereto.

[0051] In the following examples, the materials, reagents, etc. used are commercially available reagents and materials unless otherwise specified.

[0052] Examples 1-14

[0053] The raw material components of the polypropylene composition and the preparation method thereof according to the present application 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. After granulation and cooling, a polypropylene composition was obtained. The temperature of the extruder 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, and the head 200°C. The screw rotation speed was 150 rpm.

[0056] Comparative Examples 1-8

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

[0058] In the raw material components of each of the examples and comparative examples:

[0059] The polypropylene resin 1 was a homopolymer polypropylene resin, the manufacturer was ExxonMobil, and the model was PP1304E5.

[0060] The polypropylene resin 2 was a maleic anhydride grafted PP, the manufacturer was Kaois, and the model was B1.

[0061] The flame retardant 1 included dipentaerythritol and ammonium polyphosphate, and the weight ratio of the two was 1:1.

[0062] The flame retardant 2 included dipentaerythritol and sodium pyrophosphate, and the weight ratio of the two was 1:3.

[0063] The flame retardant 3 included melamine sodium pyrophosphate and sodium pyrophosphate, and the weight ratio of the two was 3:1.

[0064] The flame retardant 4 was ammonium polyphosphate.

[0065] The flame retardant 5 was dipentaerythritol.

[0066] Among the flame retardants 1-5, the manufacturer of dipentaerythritol was Jiangsu Ruichuang Chemical Co., Ltd.; the ammonium polyphosphate was from Shifang Changfeng Chemical Co., Ltd.; and the manufacturers of melamine sodium pyrophosphate and sodium pyrophosphate were both Suzhou Dongxingheng Chemical Co., Ltd.

[0067] The fluxing agent 1 was calcium borate, the manufacturer was Wuhan Jiyesheng Chemical Co., Ltd.

[0068] The fluxing agent 2 was zinc borate, the manufacturer was Shandong Wewe Flame Retardant Technology Co., Ltd.

[0069] The ceramic-forming filler 1 was olivine, the average particle size was 40 nm, and the manufacturer was Yichang Fuquan Olivine Co., Ltd.

[0070] The ceramic-forming filler 2 was wollastonite, the average particle size was 100 μm, and the manufacturer was Guangde County Zhengyuan Wollastonite Powder Co., Ltd.

[0071] The porcelain-forming filler 3 is mica powder with an average particle size of 50 microns, and the manufacturer is Foshan Bozhen Chemical Co., Ltd.

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

[0073] The functional filler 1 is barium phosphate with an average particle size of 5 microns, and the manufacturer is Anjiji Chemical.

[0074] The functional filler 2 is aluminum hypophosphite with an average particle size of 2 microns, and 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 microns, and the manufacturer is Anjiji Chemical.

[0076] The functional filler 4 is zirconium hydrogen phosphate with an average particle size of 2 microns, and the manufacturer is Fujian Ruison New Material Co., Ltd.

[0077] The above fillers are obtained by screening.

[0078] The other auxiliary agents include lubricants, antioxidants, coupling agents, and anti-dripping agents, and the mass ratio of the lubricants, antioxidants, coupling agents, and anti-dripping agents 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 Anjiji Chemical.

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

[0083] Unless otherwise specified, the component raw materials used in the embodiments and comparative examples of the present application are commercially available raw materials, and the component raw materials used in each parallel experiment are the same.

[0084] Table 1

[0085]

[0086]

[0087]

[0088] Table 2

[0089]

[0090] In order to verify the performance of the polypropylene composition according to the present application, the polypropylene composition prepared in each example and comparative example was injection molded into a sample bar for testing the following performances. The sample bar thickness was 1.5 mm.

[0091] Performance test method:

[0092] 1. Notched impact strength: tested according to GB / T 1843-2008 test standard, impact energy was 2.5 J.

[0093] 2. Tensile strength: tested according to GB / T 228.1-2021 test standard.

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

[0095] 4. Flexural performance: tested according to GB / T 9341-2000 test standard.

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

[0097] Table 3

[0098]

[0099] According to Table 1, the polypropylene composition according to the present application has excellent flame retardant performance and mechanical properties. It can be obtained from the comparison of Comparative Examples 1-3 with Example 1 that in Comparative Example 1, no ceramic-forming filler is added, in Comparative Example 2, no functional filler is added, and in Comparative Example 3, no fluxing agent is added, and the flame retardant performance of the polypropylene composition is not as good as that of Example 1, which indicates that the mutual cooperation of the ceramic-forming filler, the functional filler, the fluxing agent and the flame retardant is beneficial to improving the flame retardant performance of the polypropylene composition. In Comparative Example 4, the same mass of zeolite powder is used to replace olivine, the polypropylene composition cannot pass the 5VA test, and the mechanical properties of the polypropylene composition are reduced, which indicates that not any combination of ceramic-forming fillers and functional fillers can make the polypropylene composition have excellent flame retardant performance and mechanical properties at the same time.

[0100] It can be obtained from the comparison of Comparative Examples 5-6 with Example 1 that if the weight ratio of the ceramic-forming filler and 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 are also affected, which indicates that by controlling the weight ratio of the ceramic-forming filler and the functional filler to be (1-3): 1, it is beneficial to improving the flame retardant performance and the mechanical properties of the polypropylene composition.

[0101] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present 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 present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A polypropylene composition, characterized in that, The raw material components include the following weight parts: polypropylene resin 40-70 parts; flame retardant 10-50 parts; fluxing agent 5-30 parts; porcelain-forming filler 10-40 parts; functional filler 1-10 parts; the flame retardant includes carbon source and acid source; The porcelain-forming 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 porcelain-forming filler and the functional filler is (1-3):

1.

2. The polypropylene composition according to claim 1, characterized in that 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 and 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, zinc glycerol, 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 fluxing agent 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 includes other auxiliary agents in a weight part of 1-5 parts.

9. Process for the preparation of a polypropylene composition according to any one of claims 1 to 8, characterized in that, The method includes the following steps: After the raw material components are uniformly mixed, they are added to a double-screw extruder, granulated, and cooled to obtain the polypropylene composition.

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

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