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

Abstract

The invention relates to the technical field of high polymer materials, and discloses a flame-retardant composite material as well as a preparation method and application thereof, the flame-retardant composite material comprises the following components in parts by mass: 60-80 parts of matrix resin, 0.5-10 parts of a compatilizer and 50-150 parts of a flame retardant, the matrix resin comprises EVA, POE and EPR; the compatilizer is a mixture of EVA, POE and EPR modified by maleic anhydride; the flame retardant is prepared from a modified filler and expandable graphite in a mass ratio of 60: (1-5), and the modified filler is prepared from a silane coupling agent, magnesium hydroxide, aluminum hydroxide and magnesium oxide in a mass ratio of 1: (15-60): (40-120): (10-60). When the flame-retardant composite material is used as a cable sheath material, the flame-retardant composite material has high tensile strength, elongation at break and oxygen index.

Description

Technical Field

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

[0002] With the development of society, fire safety issues are receiving increasing attention. Among the major fire cases reported, cable fires account for a significant number, ranking first among all types of fires. This is primarily because cable fires ignite the flammable insulation and sheathing materials within the cables. The toxic gases and smoke emitted by the burning insulation and sheathing materials can cause further casualties and hinder firefighting efforts, leading to major fires. Major accidents caused by cable fires spreading into disasters result in inestimable economic losses, costly and time-consuming recovery and reconstruction efforts, and significant power losses. Therefore, using flame-retardant materials for cable sheathing to reduce the severity of fire damage is an effective preventative measure. Furthermore, with the development of emerging technologies such as new energy, big data, and cloud computing, the environments and methods in which cables are used have changed, placing higher demands on the overall performance of cables.

[0003] Therefore, it is of great significance to develop a flame-retardant composite material to simultaneously improve the tensile strength, elongation at break and oxygen index of cable sheath materials. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and to provide a flame retardant composite material and a preparation method and application thereof.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In a first aspect, the present invention provides a flame retardant composite material comprising the following components in parts by mass:

[0007] 60-80 parts of base resin, 0.5-10 parts of compatibilizer, 50-150 parts of flame retardant;

[0008] The matrix resin includes EVA (ethylene-vinyl acetate copolymer), POE (ethylene-octene copolymer) and EPR (ethylene-propylene rubber);

[0009] The compatibilizer is a mixture of EVA (ethylene-vinyl acetate copolymer), POE (ethylene-octene copolymer), and EPR (ethylene-propylene rubber) modified by maleic anhydride;

[0010] The flame retardant is a modified filler and expandable graphite in a mass ratio of 60:(1-5), and the modified filler includes a silane coupling agent, magnesium hydroxide, aluminum hydroxide, and magnesium oxide in a mass ratio of 1:(15-60):(40-120):(10-60).

[0011] When used as a cable sheath material, the flame-retardant composite material of the present invention has high tensile strength, elongation at break and oxygen index.

[0012] In the present invention, a network structure formed by connecting magnesium hydroxide, aluminum hydroxide, and magnesium oxide with a silane coupling agent is dotted with expandable graphite, forming a stable flame-retardant structure that can effectively retard heat and flame propagation, and a specific type of compatibilizer promotes the dispersion of the flame-retardant structure in a specific matrix rubber system, forming a stable, uniform internal structure with strong buffering capacity. Therefore, when the flame-retardant composite material is used as a cable sheath material, it can effectively improve the tensile strength, elongation at break, and oxygen index of the cable sheath material.

[0013] The reason why the present invention chooses to use silane coupling agent, magnesium hydroxide, aluminum hydroxide and magnesium oxide as modified fillers is that when magnesium hydroxide, aluminum hydroxide and magnesium oxide of different densities are connected with the silane coupling agent to form a network structure, the magnesium hydroxide, aluminum hydroxide and magnesium oxide, as the connection points of the network structure, will be subjected to different gravity due to their different densities, thereby distorting the network structure to form a multi-fold structure, which is conducive to wrapping and fixing the expandable graphite, forming a stable flame-retardant structure that can effectively retard heat and flame propagation, and thus can effectively improve the tensile strength, elongation at break and oxygen index of the flame-retardant composite material when used as a cable sheath material.

[0014] The reason why magnesium oxide is used instead of aluminum oxide in the modified filler of the present invention is that, under the same mass, the volume proportion of aluminum oxide with too high density is smaller than that of magnesium oxide, resulting in a smaller number of connection points in the network structure, which not only destroys the balance of the network structure, but also is not conducive to the formation of a multi-fold structure, and ultimately cannot effectively improve the tensile strength, elongation at break and oxygen index of the flame-retardant composite material when used as a cable sheath material.

[0015] In addition, in the present invention, the specific type of compatibilizer has a high degree of compatibility with the specific matrix rubber system, which can effectively promote the uniform dispersion of the flame retardant structure formed by the flame retardant in the specific matrix rubber system, thereby effectively improving the tensile strength, elongation at break and oxygen index of the flame retardant composite material when used as a cable sheath material.

[0016] Preferably, the mass ratio of the modified filler to the expandable graphite is in the range of one or any two of 60:1, 60:2, 60:3, 60:4, and 60:5.

[0017] More preferably, the mass ratio of the modified filler to the expandable graphite is 60:(1-3).

[0018] Preferably, the mass ratio of the silane coupling agent, magnesium hydroxide, aluminum hydroxide and magnesium oxide is one or any two of 1:40:80:30, 1:60:80:30, 1:15:80:30, 1:40:120:30, 1:40:40:30, 1:40:80:60 and 1:40:80:10.

[0019] More preferably, the mass ratio of the silane coupling agent, magnesium hydroxide, aluminum hydroxide and magnesium oxide is 1:(40-60):(80-120):(10-30).

[0020] Preferably, the silane coupling agent is at least one of 1,6-bistrimethoxysilylhexane (CAS No.: 87135-01-1), bis(trimethoxysilylethyl)benzene (CAS No.: 58298-01-4), bis(trimethoxysilylmethyl)ethylene (CAS No.: 143727-20-2), n-octyltriethoxysilane (OTES), 3-aminopropyltriethoxysilane (KH-550), 3-(2,3-epoxypropoxy)propyltrimethoxysilane (KH-560), and 3-(methacryloyloxy)propyltrimethoxysilane (KH-570).

[0021] Preferably, the average particle size of the magnesium hydroxide is 0.1-5 μm.

[0022] Preferably, the average particle size of the aluminum hydroxide is 0.1-5 μm.

[0023] Preferably, the average particle size of the magnesium oxide is 0.1-5 μm.

[0024] Preferably, the modified filler is prepared by mixing a silane coupling agent, magnesium hydroxide, aluminum hydroxide, and magnesium oxide to obtain the modified filler.

[0025] More preferably, the mixing method is ball milling.

[0026] More preferably, the ball milling speed is 50-600 r / min and the time is 15-60 min.

[0027] Preferably, the mesh size of the expandable graphite is 50-300 meshes.

[0028] More preferably, the mesh size of the expandable graphite is 80-150 meshes.

[0029] Preferably, the compatibilizer is prepared by mixing maleic anhydride, EVA, POE, EPR, an initiator and an antioxidant, and heating the mixture to react to obtain the compatibilizer.

[0030] More preferably, in the preparation method of the compatibilizer, the ratio of the total mass of EVA, POE and EPR to the mass of maleic anhydride is 100:(0.5-5).

[0031] More preferably, in the preparation method of the compatibilizer, the ratio of the total mass of EVA, POE and EPR to the mass of maleic anhydride is one or any two of 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, 100:5.

[0032] More preferably, in the preparation method of the compatibilizer, the ratio of the total mass of EVA, POE and EPR to the mass of maleic anhydride is 100:(0.5-4.5).

[0033] More preferably, in the preparation method of the compatibilizer, the ratio of the total mass of EVA, POE and EPR to the mass of maleic anhydride is 100:(3-4.5).

[0034] More preferably, in the preparation method of the compatibilizer, the mass ratio of EVA, POE and EPR is 6:(0.7-4):(0.15-1.5).

[0035] More preferably, in the preparation method of the compatibilizer, the mass ratio of EVA, POE and EPR is in the range of one or any two of 6:0.7:1, 6:2.5:1, 6:4:1, 6:2.5:0.15, and 6:2.5:1.5.

[0036] More preferably, in the preparation method of the compatibilizer, the mass ratio of EVA, POE and EPR is 6:(2.5-4):(1-1.5).

[0037] More preferably, in the preparation method of the compatibilizer, the ratio of the total mass of EVA, POE and EPR to the mass of the initiator is 100:(0.1-1).

[0038] More preferably, in the preparation method of the compatibilizer, the initiator is at least one of dicumyl peroxide (DCP) and tert-butyl perbenzoate (TBPB).

[0039] More preferably, in the preparation method of the compatibilizer, the ratio of the total mass of EVA, POE and EPR to the mass of the antioxidant is 100:(0.1-1).

[0040] More preferably, in the preparation method of the compatibilizer, the antioxidant is at least one of antioxidant 1010, antioxidant 168, and antioxidant DLTDP.

[0041] More preferably, in the preparation method of the compatibilizer, the reaction temperature is 175-195°C.

[0042] More preferably, in the preparation method of the compatibilizer, the reaction time is 5-20 minutes.

[0043] Preferably, the matrix resin comprises EVA, POE and EPR in a mass ratio of 1:(0.1-0.8):(0.1-0.6).

[0044] More preferably, the matrix resin comprises a mass ratio within the range of one or any two of 1:0.4:0.3, 1:0.8:0.6, 1:0.1:0.1.

[0045] More preferably, the matrix resin comprises EVA, POE and EPR in a mass ratio of 1:(0.4-0.8):(0.3-0.6).

[0046] Preferably, the flame retardant composite material further comprises at least one of an antioxidant, a dispersant, and a masterbatch.

[0047] More preferably, the mass fraction of the antioxidant is 0.5-5 parts.

[0048] More preferably, the mass fraction of the dispersant is 0.5-2 parts.

[0049] More preferably, the mass fraction of the masterbatch is 0.5-2 parts.

[0050] More preferably, the antioxidant is at least one of antioxidant 1010, 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 2-mercaptobenzimidazole zinc salt (MBZ), antioxidant 168, antioxidant DLTDP, and antioxidant DSTDP.

[0051] In the present invention, the dispersant is a commonly used dispersant in the art, for example, the dispersant is at least one of polyethylene glycol-4000 (PEG-4000), polyethylene glycol-6000 (PEG-6000), and YY-206A.

[0052] In the present invention, the masterbatch is a commonly used masterbatch in this field, for example, the masterbatch is at least one of iron oxide red, iron oxide yellow, phthalocyanine red, phthalocyanine blue, carbon black (graphitized carbon), and titanium dioxide.

[0053] In a second aspect, the present invention provides a method for preparing a flame retardant composite material, comprising: mixing various components to obtain the flame retardant composite material.

[0054] Preferably, the mixing temperature is 140-180°C.

[0055] Preferably, the method for preparing the flame-retardant composite material comprises: firstly mixing the components in the matrix resin, and then adding other components and the mixed flame retardant to obtain the flame-retardant composite material.

[0056] In a third aspect, the present invention provides an application of a flame retardant composite material in a cable.

[0057] Preferably, the application is application of the flame retardant composite material in preparing cable sheaths.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] When used as a cable sheath material, the flame-retardant composite material of the present invention has high tensile strength, elongation at break and oxygen index.

[0060] In the present invention, a network structure formed by connecting magnesium hydroxide, aluminum hydroxide, and magnesium oxide with a silane coupling agent is dotted with expandable graphite, forming a stable flame-retardant structure that can effectively retard heat and flame propagation, and a specific type of compatibilizer promotes the dispersion of the flame-retardant structure in a specific matrix rubber system, forming a stable, uniform internal structure with strong buffering capacity. Therefore, when the flame-retardant composite material is used as a cable sheath material, it can effectively improve the tensile strength, elongation at break, and oxygen index of the cable sheath material.

[0061] The reason why the present invention chooses to use silane coupling agent, magnesium hydroxide, aluminum hydroxide and magnesium oxide as modified fillers is that when magnesium hydroxide, aluminum hydroxide and magnesium oxide of different densities are connected with the silane coupling agent to form a network structure, the magnesium hydroxide, aluminum hydroxide and magnesium oxide, as the connection points of the network structure, will be subjected to different gravity due to their different densities, thereby distorting the network structure to form a multi-fold structure, which is conducive to wrapping and fixing the expandable graphite, forming a stable flame-retardant structure that can effectively retard heat and flame propagation, and thus can effectively improve the tensile strength, elongation at break and oxygen index of the flame-retardant composite material when used as a cable sheath material.

[0062] The reason why magnesium oxide is used instead of aluminum oxide in the modified filler of the present invention is that, under the same mass, the volume proportion of aluminum oxide with too high density is smaller than that of magnesium oxide, resulting in a smaller number of connection points in the network structure, which not only destroys the balance of the network structure, but also is not conducive to the formation of a multi-fold structure, and ultimately cannot effectively improve the tensile strength, elongation at break and oxygen index of the flame-retardant composite material when used as a cable sheath material.

[0063] In addition, in the present invention, the specific type of compatibilizer has a high degree of compatibility with the specific matrix rubber system, which can effectively promote the uniform dispersion of the flame retardant structure formed by the flame retardant in the specific matrix rubber system, thereby effectively improving the tensile strength, elongation at break and oxygen index of the flame retardant composite material when used as a cable sheath material. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 These are SEM images of the flame retardant composite materials of Example 1 and Comparative Example 12. Figure A is the SEM image of the flame retardant composite material of Comparative Example 12, and Figure B is the SEM image of the flame retardant composite material of Example 1.

[0065] Figure 2 These are actual pictures of vertical combustion of the flame-retardant composite materials of Example 1 and Comparative Examples 2 and 3 after heating for the same time. Figure A is a actual picture of vertical combustion of the flame-retardant composite material of Example 1, Figure B is a actual picture of vertical combustion of the flame-retardant composite material of Comparative Example 2, and Figure C is a actual picture of vertical combustion of the flame-retardant composite material of Comparative Example 3.

[0066] Figure 3 Figure A is a macroscopic morphology of the residual carbon of the flame-retardant composite material of Example 1 and Comparative Example 13 after the cone calorimeter test. Figure B is a macroscopic morphology of the residual carbon of the flame-retardant composite material of Comparative Example 13 after the cone calorimeter test. DETAILED DESCRIPTION

[0067] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0068] In the following examples, experimental methods without specific conditions are generally carried out in accordance with conventional conditions in the art or conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from conventional markets.

[0069] In the various embodiments and comparative examples of the present invention, the use of reagents is as follows:

[0070] EVA-1, EVA 240, Mitsui Chemicals, Japan;

[0071] EVA-2, EVA 40W, DuPont, USA;

[0072] POE-1, POE 8150, Dow Chemical;

[0073] POE-2, POE C1070, Saudi Basic Industries, USA;

[0074] EPR-1, EPR 4045, Jilin Petrochemical;

[0075] EPR-2, EPR 3722P, Dow Chemical, USA;

[0076] Expandable graphite-1, 150 mesh, obtained by crushing and sieving expandable graphite model 95100250 (50-100 mesh, expansion ratio 150-350 times) produced by Qingdao Risheng Graphite Co., Ltd.;

[0077] Expandable graphite-2, 80 mesh, obtained by crushing and sieving expandable graphite model 95100250 (50-100 mesh, expansion ratio 150-350 times) produced by Qingdao Risheng Graphite Co., Ltd.;

[0078] Expandable graphite-3, 50 mesh, obtained by sieving expandable graphite model 95100250 (50-100 mesh, expansion ratio 150-350 times) produced by Qingdao Risheng Graphite Co., Ltd.;

[0079] Expandable graphite - 4,300 mesh, obtained by crushing and sieving expandable graphite model 95100250 (50-100 mesh, expansion ratio 150-350 times) produced by Qingdao Risheng Graphite Co., Ltd.;

[0080] Silane coupling agent, 1,6-bistrimethoxysilylhexane, commercially available;

[0081] Magnesium hydroxide, with an average particle size of 2 μm, was obtained by crushing and classifying magnesium hydroxide (3500-5000 mesh) model M766553 produced by Shanghai Macklin. The average particle size (D50 particle size) was measured by a Malvern Panalytical laser particle size analyzer Mastersizer 3000.

[0082] Aluminum hydroxide, average particle size 1 μm, A800857, Shanghai Macklin;

[0083] Magnesium oxide, average particle size 0.1 μm, M761792, Shanghai MacLean;

[0084] Alumina, average particle size 0.1 μm, A750299, Shanghai MacLean;

[0085] Initiator, dicumyl peroxide (DCP), commercially available;

[0086] Antioxidant 1010, commercially available;

[0087] 2,2,4-Trimethyl-1,2-dihydroquinoline polymer (RD), antioxidant RD, P824729, Shanghai MacLean;

[0088] 2-Mercaptobenzimidazole zinc salt (MBZ), Z836411, Shanghai MacLean;

[0089] Dispersant, polyethylene glycol-4000 (PEG-4000), P615530, Shanghai Aladdin;

[0090] Masterbatch, carbon black (graphitized carbon), C914875, Shanghai Macklin.

[0091] Example 1

[0092] This embodiment provides a flame retardant composite material, comprising the following components in parts by mass:

[0093] 70 parts of base resin, 5 parts of compatibilizer, 85 parts of flame retardant, 3 parts of antioxidant (antioxidant 1010, RD and MBZ in a mass ratio of 1:1:2), 1 part of dispersant (PEG-4000), 1 part of masterbatch (carbon black);

[0094] The matrix resin includes EVA-1, POE-1 and EPR-1 in a mass ratio of 1:0.4:0.3;

[0095] The compatibilizer is a mixture of EVA-1, POE-1 and EPR-1 modified with maleic anhydride;

[0096] The compatibilizer is prepared by mixing maleic anhydride, EVA-1, POE-1, EPR-1, an initiator (DCP) and an antioxidant (antioxidant 1010), heating to 185° C. for reaction for 20 minutes, soaking in acetone for 30 hours, removing unreacted maleic anhydride and by-products, filtering, and vacuum drying at 60° C. to obtain the compatibilizer; wherein the mass ratio of the total mass of the EVA-1, POE-1 and EPR-1 to the mass of maleic anhydride is 100:3, and the mass ratio of the EVA-1, POE-1 and EPR-1 is 6:2.5:1; the mass ratio of the total mass of the EVA-1, POE-1 and EPR-1 to the initiator (DCP) is 100:0.5; and the mass ratio of the total mass of the EVA-1, POE-1 and EPR-1 to the antioxidant (antioxidant 1010) is 100:0.5;

[0097] The flame retardant is a modified filler and expandable graphite-1 in a mass ratio of 60:3, and the modified filler includes a silane coupling agent (1,6-bistrimethoxysilylhexane), magnesium hydroxide, aluminum hydroxide, and magnesium oxide in a mass ratio of 1:40:80:30;

[0098] The modified filler is prepared by adding a silane coupling agent (1,6-bistrimethoxysilylhexane), magnesium hydroxide, aluminum hydroxide, and magnesium oxide into a ball mill, and mixing them by ball milling at 300 r / min for 20 minutes to obtain the modified filler;

[0099] The flame retardant is prepared by mixing a modified filler and expandable graphite-1 to obtain the flame retardant;

[0100] The method for preparing the flame retardant composite material comprises:

[0101] The components of the matrix resin (EVA-1, POE-1 and EPR-1) were added to an internal mixer and mixed at 160°C for 5 minutes. Then, the other components and the mixed flame retardant were added and continued to be mixed for 7 minutes. The mixture was extruded and granulated to obtain a flame retardant composite material.

[0102] Examples 2-3 and Comparative Examples 1-3

[0103] Examples 2-3 and Comparative Examples 1-3 provide different flame retardant composite materials, which differ from Example 1 in that the mass ratio of the modified filler to the expandable graphite-1 is different, and the rest are consistent with Example 1, as shown in the following table:

[0104] Table 1 Mass ratio of modified filler and expandable graphite-1 in Examples 1-3 and Comparative Examples 1-3

[0105] Mass ratio of modified filler and expandable graphite-1 Example 1 60:3 Example 2 60:5 Example 3 60:1 Comparative Example 1 60:10 Comparative Example 2 60:0 Comparative Example 3 0:3

[0106] Examples 4-9 and Comparative Examples 4-11

[0107] Example 4-9 and Comparative Example 4-11 provide different flame retardant composite materials, which differ from Example 1 in that the mass ratios of silane coupling agent (1,6-bistrimethoxysilylhexane), magnesium hydroxide, aluminum hydroxide, and magnesium oxide in the modified filler are different, and the rest are consistent with Example 1, as shown in the following table: Table 2 Mass ratios of silane coupling agent, magnesium hydroxide, aluminum hydroxide, and magnesium oxide in Example 1, 4-9, and Comparative Example 4-11

[0108]

[0109] In the above table, "1:40:80:30 (aluminum oxide)" in Comparative Example 11 indicates that magnesium oxide is replaced by aluminum oxide in Comparative Example 11, that is, the modified filler of Comparative Example 11 includes a silane coupling agent, magnesium hydroxide, aluminum hydroxide, and aluminum oxide in a mass ratio of 1:40:80:30.

[0110] Examples 10-12

[0111] Examples 10-12 provide different flame retardant composite materials, which differ from Example 1 in that the types of expandable graphite are different. The rest are consistent with Example 1, as shown in the following table:

[0112] Table 3 Types of expandable graphite in Examples 1, 10-12

[0113]

[0114]

[0115] Examples 13-14

[0116] Examples 13-14 provide different flame retardant composite materials, which differ from Example 1 in that the ratio of the total mass of EVA-1, POE-1, and EPR-1 to the mass of maleic anhydride in the preparation method of the compatibilizer is different. The rest is consistent with Example 1, as shown in the following table:

[0117] Table 4 Ratio of the total mass of EVA-1, POE-1 and EPR-1 to the mass of maleic anhydride in the preparation method of the compatibilizer in Examples 1 and 13-14

[0118]

[0119] In the above table, "0:0" in Comparative Example 12 means that the ratio of the total mass of EVA-1, POE-1 and EPR-1 to the mass of maleic anhydride = 0:0, that is, no compatibilizer is used in Comparative Example 12.

[0120] Examples 15-18

[0121] Examples 15-18 provide different flame retardant composite materials, which differ from Example 1 in that the mass ratios of EVA-1, POE-1, and EPR-1 in the preparation method of the compatibilizer are different. The rest are consistent with Example 1, as shown in the following table:

[0122] Table 5 Mass ratio of EVA-1, POE-1 and EPR-1 in the preparation method of compatibilizers in Examples 1 and 15-18

[0123]

[0124]

[0125] Examples 19-20 and Comparative Examples 13-14

[0126] Examples 19-20 and Comparative Examples 13-14 provide different flame retardant composite materials, which differ from Example 1 in that the mass ratios of EVA-1, POE-1, and EPR-1 in the matrix resin are different. The rest are consistent with Example 1, as shown in the following table:

[0127] Table 6 Mass ratio of EVA-1, POE-1 and EPR-1 in the matrix resin of Examples 1, 19-20 and Comparative Examples 13-14

[0128]

[0129] Example 21

[0130] This embodiment provides a flame retardant composite material, comprising the following components in parts by mass:

[0131] 60 parts of base resin, 0.5 parts of compatibilizer, 50 parts of flame retardant, 0.5 parts of antioxidant (antioxidant 1010, RD and MBZ in a mass ratio of 1:1:2), 0.5 parts of dispersant (PEG-4000), and 0.5 parts of masterbatch (carbon black);

[0132] The rest are consistent with Example 1.

[0133] Example 22

[0134] This embodiment provides a flame retardant composite material, comprising the following components in parts by mass:

[0135] 80 parts of base resin, 10 parts of compatibilizer, 150 parts of flame retardant, 5 parts of antioxidant (antioxidant 1010, RD and MBZ in a mass ratio of 1:1:2), 2 parts of dispersant (PEG-4000), 2 parts of masterbatch (carbon black);

[0136] The matrix resin includes EVA-2, POE-2 and EPR-2 in a mass ratio of 1:0.4:0.3;

[0137] The compatibilizer is a mixture of EVA-2, POE-2 and EPR-2 modified with maleic anhydride;

[0138] The compatibilizer is prepared by mixing maleic anhydride, EVA-2, POE-2, EPR-2, an initiator (DCP) and an antioxidant (antioxidant 1010), heating to 185° C. for reaction for 20 minutes, soaking in acetone for 30 hours, removing unreacted maleic anhydride and by-products, filtering, and vacuum drying at 60° C. to obtain the compatibilizer; wherein the mass ratio of the total mass of the EVA-2, POE-2 and EPR-2 to the mass of maleic anhydride is 100:3, and the mass ratio of the EVA-2, POE-2 and EPR-2 is 6:2.5:1; the mass ratio of the total mass of the EVA-2, POE-2 and EPR-2 to the initiator (DCP) is 100:0.5; and the mass ratio of the total mass of the EVA-2, POE-2 and EPR-2 to the antioxidant (antioxidant 1010) is 100:0.5;

[0139] The flame retardant is a modified filler and expandable graphite-1 in a mass ratio of 60:3, and the modified filler includes a silane coupling agent (1,6-bistrimethoxysilylhexane), magnesium hydroxide, aluminum hydroxide, and magnesium oxide in a mass ratio of 1:40:80:30;

[0140] The modified filler is prepared by adding a silane coupling agent (1,6-bistrimethoxysilylhexane), magnesium hydroxide, aluminum hydroxide, and magnesium oxide into a ball mill, and mixing them by ball milling at 300 r / min for 20 minutes to obtain the modified filler;

[0141] The flame retardant is prepared by mixing a modified filler and expandable graphite-1 to obtain the flame retardant;

[0142] The method for preparing the flame retardant composite material comprises:

[0143] The components of the matrix resin (EVA-2, POE-2 and EPR-2) were added to an internal mixer and mixed at 160°C for 5 minutes. Then, the other components and the mixed flame retardant were added and continued to be mixed for 7 minutes. The mixture was extruded and granulated to obtain a flame retardant composite material.

[0144] Performance Testing

[0145] The flame retardant composite materials of each embodiment and comparative example were subjected to the following performance tests:

[0146] 1) Tensile strength test: The test was conducted in accordance with GB / T 32129-2015, with a Type 5 specimen, a tensile rate of 500 mm / min, and a passing standard of ≥10 MPa;

[0147] 2) Elongation at break test: Tested in accordance with GB / T 32129-2015, using Type 5 specimens, a tensile rate of 500 mm / min, and a pass standard of ≥180%;

[0148] 3) Oxygen index test: Tested in accordance with GB / T 32129-2015, sample type IV, qualified standard ≥ 32%;

[0149] 4) Smoke density test: Tested in accordance with GB / T 32129-2015 standard, sample thickness 1±0.1mm, 25kW / m 2 , those using a pilot flame are recorded as “flame”, those not using a pilot flame are recorded as “no flame”, the passing standard for flame is ≤100, and the passing standard for no flame is ≤350;

[0150] The experimental results are shown in the following table:

[0151] Table 7 Performance test results of various embodiments and comparative examples

[0152]

[0153]

[0154] As can be seen from Table 7, the flame-retardant composite material of the present invention has high tensile strength, elongation at break and oxygen index when used as a cable sheath material, wherein the tensile strength is ≥10 MPa, the elongation at break is ≥180%, and the oxygen index is ≥32%.

[0155] Figure 1Figure A is the SEM image of the flame-retardant composite material of Example 1 and Comparative Example 12, and Figure B is the SEM image of the flame-retardant composite material of Example 1. The SEM images of the flame-retardant composite materials of other examples are similar to Figure B.

[0156] from Figure 1 It can be seen that, compared with Comparative Example 12 in which no compatibilizer is used, the flame retardant does not agglomerate in the embodiment in which the compatibilizer is used, and the flame retardant can be evenly dispersed in the resin matrix.

[0157] Figure 2 Figures 1 and 3 show vertical combustion of the flame-retardant composite materials of Example 1 and Comparative Examples 2 and 3 after being heated for the same time. Figure A shows the vertical combustion of the flame-retardant composite material of Example 1, Figure B shows the vertical combustion of the flame-retardant composite material of Comparative Example 2, and Figure C shows the vertical combustion of the flame-retardant composite material of Comparative Example 3. The vertical combustion images of the flame-retardant composite materials of the other examples are similar to Figure A.

[0158] from Figure 2 It can be seen that after the flame retardant composite material is heated for the same time, the flame retardant composite material of Example 1 is more difficult to ignite and burn than those of Comparative Examples 2 and 3, indicating that the flame retardant composite material using a specific flame retardant of the present invention has higher flame retardant properties.

[0159] Figure 3 Figures 1 and 13 show the macroscopic morphologies of carbon residue in the flame-retardant composite materials of Example 1 and Comparative Example 13 after cone calorimetry testing. Figure A shows the macroscopic morphology of carbon residue in the flame-retardant composite material of Example 1 after cone calorimetry testing, and Figure B shows the macroscopic morphology of carbon residue in the flame-retardant composite material of Comparative Example 13 after cone calorimetry testing. The macroscopic morphologies of carbon residue in the flame-retardant composite materials of the other examples after cone calorimetry testing are similar to Figure A.

[0160] from Figure 3 As can be seen, Comparative Example 13, which contains only EVA as the matrix resin, continuously releases heat in an oxygen atmosphere, undergoing a vigorous decomposition reaction. After the reaction is complete, the flame-retardant composite material is essentially completely burned out, leaving only a small amount of char remaining. In contrast, Example 1 of the present invention, which uses EVA, POE, and EPR as the matrix resins, produces a complete and dense char layer, demonstrating superior flame retardancy.

[0161] 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 flame retardant composite material, characterized in that: The composition comprises the following components in parts by weight: 60-80 parts of base resin, 0.5-10 parts of compatibilizer, 50-150 parts of flame retardant; The matrix resin includes EVA, POE and EPR; The compatibilizer is a mixture of EVA, POE, and EPR modified with maleic anhydride; The flame retardant is a modified filler and expandable graphite in a mass ratio of 60:(1-5), and the modified filler includes a silane coupling agent, magnesium hydroxide, aluminum hydroxide, and magnesium oxide in a mass ratio of 1:(15-60):(40-120):(10-60).

2. The flame retardant composite material according to claim 1, wherein: Include at least one of the following (1)-(2): (1) The mass ratio of the modified filler to the expandable graphite is 60:(1-3); (2) The mass ratio of the silane coupling agent, magnesium hydroxide, aluminum hydroxide and magnesium oxide is 1:(40-60):(80-120):(10-30).

3. The flame retardant composite material according to claim 1, wherein: Include at least one of the following (1)-(2): (1) The mesh size of the expandable graphite is 50-300 mesh; (2) The matrix resin includes EVA, POE and EPR in a mass ratio of 1:(0.1-0.8):(0.1-0.6).

4. The flame retardant composite material according to claim 3, wherein: Include at least one of the following (1)-(2): (1) The mesh size of the expandable graphite is 80-150 mesh; (4) The matrix resin includes EVA, POE and EPR in a mass ratio of 1:(0.4-0.8):(0.3-0.6).

5. The flame retardant composite material according to claim 1, wherein: Include at least one of the following (1)-(2): (1) The modified filler is prepared by mixing a silane coupling agent, magnesium hydroxide, aluminum hydroxide, and magnesium oxide to obtain the modified filler; (2) The compatibilizer is prepared by mixing maleic anhydride, EVA, POE, EPR, an initiator and an antioxidant, and heating to react to obtain the compatibilizer.

6. The flame retardant composite material according to claim 5, characterized in that: Include at least one of the following (1)-(2): (1) In the preparation method of the compatibilizer, the ratio of the total mass of EVA, POE and EPR to the mass of maleic anhydride is 100:(0.5-5); (2) In the preparation method of the compatibilizer, the mass ratio of EVA, POE and EPR is 6:(0.7-4):(0.15-1.5).

7. The flame retardant composite material according to claim 6, wherein: Include at least one of the following (1)-(2): (1) In the preparation method of the compatibilizer, the ratio of the total mass of EVA, POE and EPR to the mass of maleic anhydride is 100:(3-4.5); (2) In the preparation method of the compatibilizer, the mass ratio of EVA, POE and EPR is 6:(2.5-4):(1-1.5).

8. The flame retardant composite material according to claim 1, wherein: Include at least one of the following (1)-(4): (1) The silane coupling agent is at least one of 1,6-bistrimethoxysilylhexane, bis(trimethoxysilylethyl)benzene, bis(trimethoxysilylmethyl)ethylene, n-octyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-(2,3-epoxypropyloxy)propyltrimethoxysilane, and 3-(methacryloyloxy)propyltrimethoxysilane; (2) the average particle size of the magnesium hydroxide is 0.1-5 μm; (3) The average particle size of the aluminum hydroxide is 0.1-5 μm; (4) The average particle size of the magnesium oxide is 0.1-5 μm; (5) The flame retardant composite material further includes at least one of an antioxidant, a dispersant, and a masterbatch.

9. The flame retardant composite material according to claim 8, wherein: Include at least one of the following (1)-(3): (1) The mass fraction of the antioxidant is 0.5-5 parts; (2) The mass fraction of the dispersant is 0.5-2 parts; (3) The mass fraction of the masterbatch is 0.5-2 parts.

10. Use of the flame retardant composite material according to any one of claims 1 to 9 in cables.

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