Flame-retardant polypropylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a flame-retardant polypropylene composite material, and relates to the technical field of high polymer materials. The flame-retardant polypropylene composite material is prepared from the following components in parts by mass: 50 to 60 parts of polypropylene resin, 10 to 20 parts of polyethylene resin, 4 to 9 parts of polyolefin elastomer, 10 to 15 parts of glass fiber, 10 to 15 parts of filler, 4 to 6 parts of compound flame retardant, 0 to 0.9 part of lubricant and 0 to 0.5 part of antioxidant, the compound flame retardant comprises a brominated flame retardant and an antimony flame retardant; the flame-retardant polypropylene composite material does not contain a compatilizer. According to the flame-retardant polypropylene composite material, the mechanical strength is improved, the shrinkage rate is reduced, the glossiness is improved, the buckling deformation is improved, meanwhile, the flame retardant property is improved, the problem that a traditional glass fiber reinforced polypropylene material is difficult to consider the mechanical strength, the shrinkage rate, the glossiness, the buckling deformation and the flame retardant property at the same time is solved, and the flame-retardant polypropylene composite material is suitable for the field of household appliance products.

Description

Technical Field

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

[0002] Polypropylene (PP) is one of the five general-purpose resins, and has excellent properties such as light weight, easy processing, and chemical resistance, and is widely used in industrial fields such as chemical industry and packaging. Among them, glass fiber-reinforced polypropylene is an important modified polypropylene material, and its higher mechanical properties enable it to be applied in more fields. For example, it can replace the relatively poor heat-resistant ABS material and be used in the field of household appliances.

[0003] However, while the glass fiber-reinforced polypropylene material improves the mechanical properties and reduces the shrinkage rate, there are still problems such as warping deformation, low gloss, and low toughness that have not been solved. Moreover, the oxygen index of polypropylene itself is relatively low, and adding fillers or glass fibers will seriously affect the dripping during the combustion process, so the flame-retardant performance is poor. These problems limit the application of the glass fiber-reinforced polypropylene material in the field of household appliances. Summary of the Invention

[0004] The present invention aims to at least solve one of the above technical problems existing in the prior art. For this reason, the object of the present invention is to provide a flame-retardant polypropylene composite material, which ensures the mechanical strength while improving the gloss, improves the warping deformation, and reduces the material shrinkage rate through the compounding of different components.

[0005] The second aspect of the present invention provides a preparation method of a flame-retardant polypropylene composite material.

[0006] The third aspect of the present invention provides an application of a flame-retardant polypropylene composite material.

[0007] In order to achieve the above object, the technical solutions adopted by the present invention are as follows:

[0008] A flame-retardant polypropylene composite material, by mass, comprises the following components:

[0009] 50-60 parts of polypropylene resin, 10-20 parts of polyethylene resin, 4-9 parts of polyolefin elastomer, 10-15 parts of glass fiber, 10-15 parts of filler, 4-6 parts of compound flame retardant, 0-0.9 parts of lubricant, 0-0.5 parts of antioxidant;

[0010] The compound flame retardant comprises a bromine-based flame retardant and an antimony-based flame retardant; the flame-retardant polypropylene composite material does not contain a compatibilizer.

[0011] In traditional glass fiber-reinforced polypropylene materials, a compatibilizer is generally added to help improve the rigidity of the material. However, the present invention has found that the addition of the compatibilizer, which acts as a bridge to connect the polypropylene resin and the glass fiber, will affect the dispersion of the glass fiber in the polypropylene composite material system, thereby resulting in serious anisotropy and causing obvious warpage deformation of the obtained flame-retardant polypropylene composite material. In the flame-retardant polypropylene composite material of the present invention, no compatibilizer is added, and the dispersion of the glass fiber in the system is better, which is beneficial to improving the rigidity of the flame-retardant polypropylene composite material and reducing the shrinkage rate. At the same time, due to the insignificant anisotropy, the warpage deformation is improved. In addition, in the flame-retardant polypropylene material of the present invention, a brominated flame retardant and an antimony-based flame retardant are used in combination, and the flame retardant performance is relatively stable. The flame retardant performance can be improved with a relatively small addition amount, and good cooperation can be formed with other components to avoid negative impacts on mechanical strength, gloss, warpage deformation, shrinkage rate, etc.

[0012] The present invention also regulates the amounts of each component. Through the compounding of different components and the optimization of the amounts, the mechanical strength, gloss, shrinkage rate and warpage deformation of the flame-retardant polypropylene composite material are better balanced.

[0013] It should be understood that the compatibilizer includes common compatibilizers such as maleic anhydride-grafted polypropylene.

[0014] Preferably, the flame-retardant polypropylene composite material, by mass parts, comprises the following components:

[0015] 50-55 parts of polypropylene resin, 10-15 parts of polyethylene resin, 4-8 parts of polyolefin elastomer, 10-15 parts of glass fiber, 10-15 parts of filler, 4-6 parts of compound flame retardant, 0.6-0.9 parts of lubricant, 0.1-0.4 parts of antioxidant.

[0016] Preferably, the brominated flame retardant includes octabromobisphenol S ether; the antimony-based flame retardant includes antimony trioxide.

[0017] More preferably, the mass ratio of the brominated flame retardant to the antimony-based flame retardant is (2-4):1.

[0018] More preferably, the whiteness of both the brominated flame retardant and the antimony-based flame retardant is ≥98%.

[0019] The present invention further selects octabromobisphenol S ether and antimony trioxide as flame retardants to improve the flame retardancy performance, enabling the material to not only reach the UL94 V-2 flame retardant rating but also meet the glow wire test of GWFI 3.0 / 850 in IEC60695-2-12, and can be applied to plastic components near some live bodies. Meanwhile, the high whiteness octabromobisphenol S ether and antimony trioxide as flame retardants are also beneficial to achieving the high gloss of the flame retardant polypropylene composite material. In addition, within a certain range of the compounded flame retardant ratio, the flame retardant efficiency and economic benefits can be taken into account.

[0020] Preferably, the melt index of the polyolefin elastomer at 190 °C and under a load of 2.16 kg is 0.05 - 1.5 g / 10 min.

[0021] More preferably, the melt index of the polyolefin elastomer at 190 °C and under a load of 2.16 kg is 0.2 - 0.8 g / 10 min.

[0022] The present invention discovers that by further selecting polyolefin elastomers within a specific melt index range, their toughening effect as toughening agents is higher, and the melt strength of such polyolefin elastomers themselves is higher, which is beneficial to improving the toughness of the flame retardant polypropylene composite material.

[0023] Preferably, the polyolefin elastomer includes at least one of ethylene-butene copolymer and ethylene-octene copolymer.

[0024] Preferably, the melt index of the polypropylene resin at 230 °C and under a load of 2.16 kg is 26 - 110 g / 10 min.

[0025] More preferably, the melt index of the polypropylene resin at 230 °C and under a load of 2.16 kg is 26 - 80 g / 10 min.

[0026] Even more preferably, the melt index of the polypropylene resin at 230 °C and under a load of 2.16 kg is 26 - 72 g / 10 min.

[0027] Preferably, the flexural modulus of the polypropylene resin is 1200 - 2300 MPa.

[0028] More preferably, the flexural modulus of the polypropylene resin is 1200 - 1800 MPa.

[0029] Even more preferably, the flexural modulus of the polypropylene resin is 1400 - 1500 MPa.

[0030] The present invention selects a high-flow polypropylene resin with a specific melt index, which is beneficial to promoting the flow of glass fibers in all directions during the processing, making the glass fiber dispersion more sufficient, further eliminating the influence brought by anisotropy, and being beneficial to improving the warpage deformation of the flame-retardant polypropylene composite. In addition, the present invention selects a polypropylene resin with a relatively high flexural modulus, which is beneficial to improving the rigidity of the flame-retardant polypropylene composite. By coordinating with the adjustment of the melt index, the rigidity and toughness of the material are balanced.

[0031] Preferably, the melt index of the polyethylene resin at 190 °C under a load of 2.16 kg is 50-170 g / 10 min.

[0032] More preferably, the melt index of the polyethylene resin at 190 °C under a load of 2.16 kg is 55-95 g / 10 min.

[0033] Even more preferably, the melt index of the polyethylene resin at 190 °C under a load of 2.16 kg is 60-80 g / 10 min.

[0034] Preferably, the Izod notched impact strength of the polyethylene resin is 300-800 J / m.

[0035] More preferably, the Izod notched impact strength of the polyethylene resin is 300-600 J / m.

[0036] Even more preferably, the Izod notched impact strength of the polyethylene resin is 300-400 J / m.

[0037] The present invention selects a polyethylene resin with a melt index and an Izod notched impact strength within a certain range, which is beneficial to improving the impact strength of the flame-retardant polypropylene composite, enhancing the gloss of the flame-retardant polypropylene composite, and reducing the warpage deformation of the flame-retardant polypropylene composite.

[0038] Preferably, the glass fiber includes at least one of chopped glass fiber and continuous roving.

[0039] Preferably, the fiber diameter of the glass fiber is 10-30 μm.

[0040] More preferably, the fiber diameter of the glass fiber is 10-15 μm.

[0041] The present invention selects a glass fiber with a specific fiber diameter. Within this fiber diameter range, the glass fiber can be better dispersed in the flame-retardant polypropylene composite system, further improving the rigidity of the flame-retardant polypropylene composite and reducing the shrinkage rate.

[0042] Preferably, the filler is barium sulfate; the whiteness of the filler ≥ 98%.

[0043] Preferably, the average particle size of the filler is 2000 to 3000 mesh.

[0044] More preferably, the average particle size of the filler is 2300 to 2700 mesh.

[0045] The present invention selects barium sulfate with high whiteness and low particle size as the filler. On the one hand, it is beneficial to improve the gloss and whiteness of the flame-retardant polypropylene composite material, reduce the shrinkage rate and production cost of the flame-retardant polypropylene composite material. On the other hand, when adding a specific filler to the flame-retardant polypropylene composite material for preparing injection-molded parts, during the injection molding process, the filler can fill the cavities between the polypropylene resin, polyethylene resin and glass fiber, which is beneficial to reducing the warpage deformation of the flame-retardant polypropylene composite material. In addition, the present invention also finds that compared with other fillers, barium sulfate has a lower negative impact on the flame-retardant performance of the material, which is beneficial to ensuring the flame-retardant effect of the flame-retardant polypropylene composite material.

[0046] Preferably, the lubricant includes at least one of polyethylene wax and polar wax.

[0047] More preferably, the lubricant includes polyethylene wax and polar wax; the mass ratio of the polyethylene wax to the polar wax is 1:(1.5 - 2.5).

[0048] By adding polyethylene wax and / or polar wax as the lubricant, the present invention can improve the internal and external lubricity of the flame-retardant polypropylene composite material, increase the melt fluidity, reduce the demolding force, disperse the glass fiber more effectively, improve the gloss of the surface of the flame-retardant polypropylene composite material, and due to the reduced cost of the lubricant used, it helps to balance the economy.

[0049] Preferably, the antioxidant includes at least one of hindered phenol antioxidants and phosphite antioxidants.

[0050] More preferably, the antioxidant is a composite antioxidant of hindered phenol antioxidants and phosphite antioxidants.

[0051] The second aspect of the present invention provides a preparation method of the flame-retardant polypropylene composite material described in the first aspect of the present invention, including the following steps:

[0052] Mix, melt and extrude the components to obtain the described flame-retardant polypropylene composite material.

[0053] Preferably, the preparation method of the flame-retardant polypropylene composite material includes the following steps:

[0054] Mix polypropylene resin, polyethylene resin, polyolefin elastomer, filler, compound flame retardant, lubricant and antioxidant, and add them into a twin-screw extruder from the main feeding port. Glass fiber is added from the side feeding port or the fiber adding port. After mixing and melting, extrude and pelletize through the twin-screw extruder to obtain the described flame-retardant polypropylene composite material.

[0055] Preferably, the temperature of the extrusion is 200 - 230 °C.

[0056] The third aspect of the present invention provides an application of the flame-retardant polypropylene composite material described in the first aspect of the present invention in the preparation of household electrical appliances.

[0057] The flame-retardant polypropylene composite material obtained by the present invention not only has high mechanical strength, good rigidity and toughness, but also solves the problems of warpage deformation, low gloss and poor flame-retardant performance existing in traditional glass fiber reinforced polypropylene materials. It has the advantages of high gloss, low shrinkage rate, low warpage deformation and high flame retardancy, and can be used in the preparation of household electrical appliances.

[0058] Compared with the prior art, the beneficial effects of the present invention are:

[0059] 1) In the flame-retardant polypropylene composite material provided by the present invention, no compatibilizer is added. By using a specific compound flame retardant and adjusting the compounding and dosage of different components, while improving the mechanical strength of the flame-retardant polypropylene composite material, reducing the shrinkage rate, increasing the gloss, and reducing the warpage deformation of the injection-molded parts of the flame-retardant polypropylene composite material, the flame-retardant performance of the polypropylene composite material is improved, and the problem that traditional glass fiber reinforced polypropylene materials are difficult to balance mechanical properties, shrinkage rate, gloss, warpage deformation and flame-retardant performance is solved.

[0060] 2) By further selecting polypropylene resin, polyethylene resin with specific parameters, and specific polyolefin elastomer, filler and flame retardant, the warpage deformation and flame-retardant performance of the flame-retardant polypropylene composite material are further improved, the rigidity and toughness of the flame-retardant polypropylene composite material are enhanced, and the flame-retardant polypropylene composite material has higher gloss, lower shrinkage rate and smaller warpage deformation. The gloss (60°) of the obtained polyolefin resin is not less than 60%, the flat warpage height does not exceed 1.1 mm, the shrinkage rate does not exceed 0.7%, the tensile strength is not less than 30 MPa, the flexural modulus is not less than 2740 MPa, and the impact strength is not less than 100 J / m.

[0061] 3) The preparation method of the flame-retardant polypropylene composite material provided by the present invention is simple, easy to realize large-scale production, and the product quality is stable and the production cost is low.

[0062] 4) The flame-retardant polypropylene composite material obtained by the present invention not only has high mechanical strength, but also solves the problems of warpage deformation, low gloss, and poor flame-retardant performance existing in traditional glass fiber-reinforced polypropylene materials. It has the advantages of high gloss, low shrinkage rate, low warpage deformation, and high flame retardancy, and can be used in the preparation of household electrical appliances, especially for the preparation of the outer shells of household electrical appliances. Detailed Embodiments

[0063] The content of the present invention will be further described in detail through specific embodiments below. The raw materials, reagents, or devices used in the embodiments and comparative examples can be obtained from conventional commercial channels or can be obtained by existing technical methods without special instructions. Unless otherwise specified, the test or testing methods are conventional methods in the art.

[0064] The raw materials used in the following embodiments and comparative examples of the present invention are described as shown in Table 1 below:

[0065] Table 1 Raw Material Description Table of Embodiments and Comparative Examples

[0066]

[0067]

[0068] The lubricants used in the embodiments and comparative examples of the present invention are all lubricants obtained by mixing polyethylene wax (PE wax) and polar wax in a mass ratio of 1:2.

[0069] The following will be described in detail in combination with specific embodiments and comparative examples.

[0070] Examples 1-4

[0071] Examples 1-4 provide a flame-retardant polypropylene composite material. The formula is shown in Table 2, and the preparation method includes the following steps:

[0072] Mix polypropylene resin, polyethylene resin, polyolefin elastomer, filler, flame retardant, lubricant, and antioxidant evenly in proportion, and add them into a twin-screw extruder from the main feed port. Add glass fiber from the side feed port or fiber adding port. When the glass fiber is chopped glass fiber, it is added from the side feed port, and when it is continuous roving, it is added from the fiber adding port; then melt in the twin-screw extruder, and carry out extrusion and granulation to obtain the flame-retardant polypropylene composite material; the extrusion temperatures of the first to eleventh zones of the twin-screw extruder are 200°C, 220°C, 220°C, 220°C, 225°C, 225°C, 225°C, 230°C, 230°C, 220°C, and 210°C respectively.

[0073] Table 2 Formula Table of Flame-Retardant Polypropylene Composite Materials in Examples 1-4 (parts by mass)

[0074]

[0075]

[0076] Among them, the compound flame retardants used in Examples 1 to 4 are all compound flame retardants obtained by mixing octabromobisphenol S ether and antimony trioxide in a mass ratio of 3:1.

[0077] Comparative Example 1

[0078] A flame-retardant polypropylene composite material was prepared in this comparative example. The difference from Example 1 is that: the polypropylene resin PPZ30S was replaced with an equal amount of polypropylene resin PP EP548R; for the specific formulation dosage, see Table 3, and the preparation method was the same as that of Example 1.

[0079] Comparative Example 2

[0080] A flame-retardant polypropylene composite material was prepared in this comparative example. The difference from Example 2 is that: the polyethylene resin LDPE MG70 was replaced with an equal amount of polyethylene resin LDPE 2420H; for the specific formulation dosage, see Table 3, and the preparation method was the same as that of Example 2.

[0081] Comparative Example 3

[0082] A flame-retardant polypropylene composite material was prepared in this comparative example. The difference from Example 2 is that: the polyethylene resin LDPE MG70 was replaced with an equal amount of polyethylene resin LLDPE M2320; for the specific formulation dosage, see Table 3, and the preparation method was the same as that of Example 2.

[0083] Comparative Example 4

[0084] A flame-retardant polypropylene composite material was prepared in this comparative example. The difference from Example 3 is that: the polyethylene resin LDPE MG70 was replaced with an equal amount of polyethylene resin HDPE 5502; for the specific formulation dosage, see Table 3, and the preparation method was the same as that of Example 3.

[0085] Comparative Example 5

[0086] A flame-retardant polypropylene composite material was prepared in this comparative example. The difference from Example 4 is that: the polyolefin elastomer POE 9061 was replaced with an equal amount of polyolefin elastomer POE 6202; for the specific formulation dosage, see Table 3, and the preparation method was the same as that of Example 4.

[0087] Comparative Example 6

[0088] A flame-retardant polypropylene composite material was prepared in this comparative example. The difference from Example 2 is that: barium sulfate was replaced with an equal amount of talc; for the specific formulation dosage, see Table 3, and the preparation method was the same as that of Example 2.

[0089] Comparative Example 7

[0090] This comparative example prepared a flame-retardant polypropylene composite material, which was different from Example 2 in that barium sulfate was replaced with calcium carbonate in equal amounts; for the specific formulation dosage, see Table 3, and the preparation method was the same as that of Example 2.

[0091] Comparative Example 8

[0092] This comparative example prepared a flame-retardant polypropylene composite material, which was different from Example 3 in that a compatibilizer was added and the addition amount of polypropylene resin was reduced accordingly; for the specific formulation dosage, see Table 4, and the preparation method was the same as that of Example 3.

[0093] Comparative Example 9

[0094] This comparative example prepared a flame-retardant polypropylene composite material, which was different from Example 3 in that polyethylene resin was not added and the addition amount of polypropylene resin was increased accordingly; for the specific formulation dosage, see Table 4, and the preparation method was the same as that of Example 3.

[0095] Comparative Example 10

[0096] This comparative example prepared a flame-retardant polypropylene composite material, which was different from Example 1 in that polyolefin elastomer was not added and the addition amount of polypropylene resin was increased accordingly; for the specific formulation dosage, see Table 4, and the preparation method was the same as that of Example 1.

[0097] Comparative Example 11

[0098] This comparative example prepared a flame-retardant polypropylene composite material, which was different from Example 1 in that barium sulfate was not added and the addition amount of chopped glass fiber was increased accordingly; for the specific formulation dosage, see Table 4, and the preparation method was the same as that of Example 1.

[0099] Comparative Example 12

[0100] This comparative example prepared a flame-retardant polypropylene composite material, which was different from Example 1 in that chopped glass fiber was not added and the addition amount of barium sulfate was increased accordingly; for the specific formulation dosage, see Table 4, and the preparation method was the same as that of Example 1.

[0101] Comparative Example 13

[0102] This comparative example prepared a flame-retardant polypropylene composite material, which was different from Example 3 in that the compound flame retardant with a mass ratio of octabromobisphenol S ether: antimony trioxide = 3:1 was replaced with a flame retardant with a mass ratio of decabromodiphenylethane: antimony trioxide = 3:1 in equal amounts; for the specific formulation dosage, see Table 4, and the preparation method was the same as that of Example 3.

[0103] Comparative Example 14

[0104] In this comparative example, a flame-retardant polypropylene composite material was prepared, which differed from Example 3 in that the compound flame retardant was replaced in equal amount by a conventional flame retardant with a mass ratio of piperazine pyrophosphate: melamine polyphosphate = 2:1, instead of the compound flame retardant with a mass ratio of octabromobisphenol S ether: antimony trioxide = 3:1. For the specific formulation dosage, refer to Table 4, and the preparation method was the same as that in Example 3.

[0105] Table 3 Formulation Table of Flame-Retardant Polypropylene Composite Materials for Comparative Examples 1 - 7 (parts by mass)

[0106]

[0107]

[0108] Table 4 Formulation Table of Flame-Retardant Polypropylene Composite Materials for Comparative Examples 8 - 14 (parts by mass)

[0109]

[0110] Result Detection

[0111] The flame-retardant polypropylene composite materials obtained in the above examples and comparative examples were injection molded using a horizontal injection molding machine to obtain specimens. The conditions for injection molding were as follows: the four-stage injection temperatures from the feeding port to the nozzle were 195 °C, 200 °C, 200 °C, and 195 °C in sequence; the injection pressure was 55 MPa, the holding pressure time was 8 s, the cooling time was 8 s, and the materials were dried at 105 °C for 2 h before injection. The specifications of the specimens were determined according to the requirements of the tests, and the obtained specimens were used for performance tests. The test methods were as follows:

[0112] Melt Index (MI): Tested with reference to ASTM D1238 - 2010 standard, at a temperature of 230 °C and a load of 2.16 kg;

[0113] Tensile Strength: Tested with reference to ASTM D638 - 2010 standard, with the thickness of the specimen strip being 3.0 mm;

[0114] Flexural Property: Tested with reference to ASTM D790 - 2017 standard, with the thickness of the specimen strip being 3.0 mm;

[0115] Izod Notch Impact Strength: Tested with reference to ASTM D256 - 2010 standard, with the thickness of the specimen strip being 3.0 mm;

[0116] Flat Plate Warpage Height: Fix one end of the gate of the injection molded long and flat plate specimen (150 mm * 450 mm * 1.5 mm), and measure the warpage height at the end of the plate;

[0117] Glossiness: Tested with reference to ISO 2813 standard, and record the glossiness measured under the condition of 60°;

[0118] Shrinkage rate: For the injection-molded square plate (150mm * 150mm * 3.0mm), measure the width of the square plate after cooling, and calculate the shrinkage rate based on the width difference.

[0119] Flame retardancy performance: Test according to the UL94 V-2 grade standard, with the sample thickness of 1.5mm.

[0120] Glow wire performance (GWFI 850 / 3.0): Test according to the IEC60695-2-12 standard, with the sample size of 15 * 15 * 3.0mm and the test temperature of 850°C.

[0121] See Tables 5 - 7 for the test results.

[0122] Table 5 Performance test results of the flame-retardant polypropylene composites in Examples 1 - 4

[0123] Test Items Example 1 Example 2 Example 3 Example 4 MI (g / 10min) 13 26 12 22 Tensile Strength (MPa) 31 32 30 33 Flexural Modulus (MPa) 2790 2920 2740 3085 Impact Strength (J / m) 115 100 130 110 Flat Plate Warpage Height (mm) 1.1 0.8 0.9 1.1 Glossiness (60°, %) 63 66 64 62 Shrinkage Rate (%) 0.5 0.6 0.7 0.5 Flame Retardant Performance UL94V-2 Qualified Qualified Qualified Qualified Glow Wire Performance Qualified Qualified Qualified Qualified

[0124] As can be seen from Table 5, the injection-molded parts of the flame-retardant polypropylene composites obtained in Examples 1 - 4 of the present invention have a tensile strength of not less than 30MPa, a flexural modulus of not less than 2740MPa, a notched Izod impact strength of not less than 100J / m, and the glossiness at a 60° angle of the glossy surface is all above 60%. The shrinkage rate does not exceed 0.7%, and the flatness warpage height does not exceed 1.1mm. It has good flame retardancy performance and meets the GWFI 850 / 3.0 glow wire performance of IEC60695-2-12. It can be seen that the flame-retardant polypropylene composite of the present invention has excellent mechanical strength, high glossiness, low shrinkage rate, and insignificant warpage deformation. While ensuring these properties, it also takes into account the flame retardancy performance and reaches the UL94 V-2 level of flame retardancy. In addition, the flame-retardant polypropylene composites obtained in Examples 1 - 4 of the present invention also have a moderate melt index, which is beneficial to production and processing and ensures the material strength.

[0125] Table 6 Performance test results of the flame-retardant polypropylene composites in Comparative Examples 1 - 7

[0126]

[0127]

[0128] Table 7 Performance test results of the flame-retardant polypropylene composites in Comparative Examples 8 - 14

[0129]

[0130] As can be seen from Table 5 to Table 7, compared with Examples 1 to 4, for the flame-retardant polypropylene composite of Comparative Example 1, the replacement of the polypropylene resin results in a significant decrease in the gloss of the obtained material, unable to meet the requirement of high gloss; for the flame-retardant polypropylene composites of Comparative Examples 2 to 3, the polyethylene resin is replaced, and LDPE or LLDPE with a lower melt index is used, resulting in a decrease in the gloss of the obtained material. At the same time, the decrease in fluidity leads to poor warpage deformation; for the flame-retardant polypropylene composite of Comparative Example 4, the polyethylene resin is replaced with HDPE with a lower melt index, resulting in a serious decrease in fluidity, leading to severe warpage, lower gloss, and problems such as unsmooth dripping during combustion and unqualified flame-retardant performance; for the flame-retardant polypropylene composite of Comparative Example 5, the polyolefin elastomer is replaced, resulting in a decrease in the toughening effect and a decrease in the impact strength of the obtained material; for the flame-retardant polypropylene composites of Comparative Examples 6 to 7, the filler barium sulfate is replaced with other fillers, resulting in a significant decrease in gloss, and when calcium carbonate is used as the filler, the flame-retardant performance is seriously affected, unable to reach the UL94 V-2 grade; for the flame-retardant polypropylene composite of Comparative Example 8, a compatibilizer is added. Although the mechanical properties are significantly improved, due to the problem of glass fiber dispersion, the anisotropy is serious and the warpage deformation is more serious; for the flame-retardant polypropylene composite of Comparative Example 9, no polyethylene resin is added, and the warpage deformation is obvious, unable to improve the warpage deformation problem of the material; for the flame-retardant polypropylene composite of Comparative Example 10, no polyolefin elastomer is added, resulting in a lower impact strength, and at the same time, the warpage deformation is more obvious, making it difficult to be applied in household electrical appliances; for the flame-retardant polypropylene composite of Comparative Example 11, no barium sulfate is added, but more glass fibers are added, resulting in more obvious warpage deformation of the obtained material, and a decrease in gloss and flame-retardant performance; for the flame-retardant polypropylene composite of Comparative Example 12, no glass fiber is added. Although the gloss increases, the mechanical strength decreases seriously and the shrinkage rate becomes larger, making it difficult to be applied in the field of household electrical appliances; for the flame-retardant polypropylene composite of Comparative Example 13, the flame retardant is replaced. During the combustion test, the dripping is unsmooth, the afterflame time is long, the flame-retardant performance decreases, and the whiteness of decabromodiphenylethane itself is relatively low, resulting in a decrease in the overall gloss of the material, unable to meet the requirement of high gloss; for the flame-retardant polypropylene composite of Comparative Example 14, the compound flame retardant is replaced with a commercially available conventional intumescent compound flame retardant, resulting in a serious decrease in flame-retardant performance, unable to reach UL94 V-2. At the same time, there is also a more serious problem of warpage deformation, and the whiteness of this flame retardant is relatively low, resulting in a significant decrease in the overall gloss of the material.

[0131] In summary, through the compounding of specific components, the flame-retardant polypropylene composite material of the present invention not only ensures the mechanical strength of the flame-retardant polypropylene composite material, reduces the shrinkage rate, improves the glossiness, and improves the warpage deformation of the injection molded parts of the flame-retardant polypropylene composite material, but also enhances the flame-retardant performance of the polypropylene composite material, reaching the UL94 V-2 level, solving the problem that traditional glass fiber-reinforced polypropylene materials are difficult to balance mechanical strength, shrinkage rate, glossiness, warpage deformation and flame-retardant performance. The obtained flame-retardant polypropylene composite material is applicable to the field of household electrical appliance products and can be used for preparing the outer shells of household electrical appliance products.

[0132] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A flame-retardant polypropylene composite material, characterized in that, By mass parts, it includes the following components: 50 - 60 parts of polypropylene resin, 10 - 20 parts of polyethylene resin, 4 - 9 parts of polyolefin elastomer, 10 - 15 parts of glass fiber, 10 - 15 parts of filler, 4 - 6 parts of compound flame retardant, 0 - 0.9 parts of lubricant, 0 - 0.5 parts of antioxidant; The compound flame retardant includes brominated flame retardant and antimony - based flame retardant; The flame - retardant polypropylene composite does not contain a compatibilizer.

2. The flame-retardant polypropylene composite material according to claim 1, wherein, The brominated flame retardant includes octabromobisphenol S ether; the antimony - based flame retardant includes antimony trioxide; And / or, the mass ratio of the brominated flame retardant to the antimony - based flame retardant is (2 - 4):

1.

3. The flame-retardant polypropylene composite material according to claim 1, wherein The melt index of the polyolefin elastomer at 190°C and 2.16 kg load is 0.05 - 1.5 g / 10 min; And / or, the polyolefin elastomer includes at least one of ethylene - butene copolymer and ethylene - octene copolymer.

4. The flame-retardant polypropylene composite material according to claim 1, wherein The melt index of the polypropylene resin at 230°C and 2.16 kg load is 26 - 110 g / 10 min; And / or, the flexural modulus of the polypropylene resin is 1200 - 2300 MPa.

5. The flame-retardant polypropylene composite material according to claim 1, wherein The melt index of the polyethylene resin at 190°C and 2.16 kg load is 50 - 170 g / 10 min; And / or, the Izod notched impact strength of the polyethylene resin is 300 - 800 J / m.

6. The flame-retardant polypropylene composite material according to claim 1, wherein The glass fiber includes at least one of chopped glass fiber and continuous roving; And / or, the wire diameter of the glass fiber is 10 - 30 μm.

7. The flame-retardant polypropylene composite material according to claim 1, wherein The filler includes barium sulfate; And / or, the lubricant includes at least one of polyethylene wax and polar wax; And / or, the antioxidant includes at least one of hindered phenol antioxidants and phosphite antioxidants.

8. A method for preparing the flame-retardant polypropylene composite material according to any one of claims 1 to 7, characterized in that, It includes the following steps: Mix, melt, and extrude each component to obtain the flame - retardant polypropylene composite.

9. The preparation method according to claim 8, characterized in that, The temperature of the extrusion is 200 - 230°C.

10. Use of the flame - retardant polypropylene composite according to any one of claims 1 - 7 in the preparation of household electrical appliances.

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