Composite polypropylene insulating material, preparation method thereof and application of composite polypropylene insulating material in preparation of low-voltage cable in flight body cabin

Abstract

The invention discloses a composite polypropylene insulating material, a preparation method thereof and application of the composite polypropylene insulating material in preparation of a low-voltage cable in a flight body cabin. The composite polypropylene insulating material comprises the following components in parts by weight: 30-100 parts of a resin composition containing polypropylene; 0-10 parts of a compatilizer; 0.5 to 1.5 parts of a surface modifier; 15-25 parts of a nitrogen flame retardant; 10-15 parts of a phosphorus-based flame retardant; 0-5 parts of a smoke suppressant; and 0.5-1 part of an antioxidant. The composite polypropylene insulating material disclosed by the invention has the characteristics of excellent halogen-free flame retardant property, low smoke, low toxicity and excellent high and low temperature resistance; the cable material can meet the requirements on smoke density and smoke toxicity of cable materials in the CCAR-25-R4 standard, and also meets the requirement on C-grade temperature resistance in the ISO 19642 standard of automobile wires; the composite polypropylene insulating material has excellent comprehensive performance, and is suitable for being used as an insulating layer for a low-voltage cable in a flight body cabin.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composite materials, and in particular to a composite polypropylene insulating material and a preparation method thereof, and application thereof in the preparation of low-voltage cables in a flight cabin. Background Art

[0002] At present, the insulation materials for communication lines on the market are mainly PE, PP, XLPO, PVC or fluorine-containing materials. With the trend of environmental protection and industry development, PVC and fluorine-containing materials will be gradually replaced. The temperature resistance level of ordinary PE materials cannot meet the C-level temperature resistance requirements of the ISO 19642 standard for automotive lines. XLPE needs to add cross-linking agents, and the residual components lead to high dielectric loss of the material. In addition, it needs to go through an irradiation process, which prolongs the production cycle and increases production costs. PP materials are not widely used in cables, and the flame retardant effects of PP products from different manufacturers vary greatly.

[0003] A Chinese patent application document (publication number: CN103443872A) discloses a cable. The composition involved in the patent contains halogen products, and the corresponding temperature resistance requirements are not mentioned. It is impossible to meet the requirements of halogen-free, smoke density, smoke toxicity and temperature resistance for materials in the cabin of the flight body. A Chinese patent application document (publication number: CN115926304A) discloses an insulating material for silane self-crosslinking cables and a preparation method thereof. The processing of this patent is more complicated and the specific gravity is higher. At the same time, the test results of smoke density and smoke toxicity are not mentioned. It is impossible to determine whether the material meets the requirements of low-altitude flight body materials. A Chinese patent application document (publication number: CN117402497A) discloses a long-term high temperature resistant silicone rubber and its preparation method and application. The patent mentions the application of aerospace cables, but does not mention the relevant flame retardant, smoke density and smoke toxicity requirements. At the same time, it requires cross-linking, and the production and manufacturing requirements are relatively high. This patent cannot determine whether it meets the relevant requirements of CCAR-25-R4.

[0004] In summary, there are currently few existing technologies related to low-voltage cable insulation materials in aircraft cabins; therefore, a method is provided that has the advantages of high flame retardancy, high temperature resistance, low smoke density and smoke toxicity, which can have broad application prospects in the field of low-voltage cable insulation layers, especially in the field of low-voltage cable insulation layers in aircraft cabins. Summary of the invention

[0005] In order to overcome at least one of the technical problems existing in the prior art, the present invention provides a composite polypropylene insulating material and a preparation method thereof and an application thereof in preparing a low-voltage cable in a cabin of an aircraft.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention first provides a composite polypropylene insulating material, which comprises the following components in parts by weight: 30 to 100 parts of a resin composition containing polypropylene; 0 to 10 parts of a compatibilizer; 0.5 to 1.5 parts of a surface modifier; 15 to 25 parts of a nitrogen-based flame retardant; 10 to 15 parts of a phosphorus-based flame retardant; 0 to 5 parts of a smoke suppressant; and 0.5 to 1 part of an antioxidant.

[0008] Preferably, the polypropylene-containing resin composition comprises polypropylene resin, SEBS resin, elastomer resin and PPO resin.

[0009] Preferably, the weight proportions of the polypropylene resin, SEBS resin, elastomer resin and PPO resin are respectively:

[0010] 30-55 parts of polypropylene resin; 1-15 parts of SEBS resin; 1-15 parts of elastomer resin; 1-10 parts of PPO resin;

[0011] Further preferably, the weight proportions of the polypropylene resin, the SEBS resin, the elastomer resin and the PPO resin are respectively:

[0012] 30-40 parts of polypropylene resin; 5-15 parts of SEBS resin; 5-15 parts of elastomer resin; 5-10 parts of PPO resin.

[0013] Preferably, the composite polypropylene insulating material comprises the following components in parts by weight: 30 to 55 parts of polypropylene resin; 1 to 15 parts of SEBS resin; 1 to 15 parts of elastomer resin; 1 to 10 parts of PPO resin; 5 to 10 parts of compatibilizer; 0.5 to 1.5 parts of surface modifier; 15 to 25 parts of nitrogen-based flame retardant; 10 to 15 parts of phosphorus-based flame retardant; 0 to 5 parts of smoke suppressant; and 0.5 to 1 part of antioxidant.

[0014] Further preferably, the composite polypropylene insulation material comprises the following components in parts by weight: 30 to 40 parts of polypropylene resin; 5 to 15 parts of SEBS resin; 5 to 15 parts of elastomer resin; 5 to 10 parts of PPO resin; 0 to 10 parts of compatibilizer; 1 to 1.5 parts of surface modifier; 15 to 25 parts of nitrogen-based flame retardant; 10 to 15 parts of phosphorus-based flame retardant; 3 to 5 parts of smoke suppressant; and 0.5 to 1 part of antioxidant.

[0015] Preferably, the elastomeric resin is selected from at least one of ethylene-propylene copolymer, ethylene-octene copolymer and ethylene-vinyl acetate copolymer.

[0016] Most preferably, further preferably, the elastomeric resin is an ethylene-octene copolymer.

[0017] Preferably, the compatibilizer is selected from at least one of maleic anhydride grafted polypropylene, maleic anhydride grafted ethylene-vinyl acetate copolymer, maleic anhydride grafted ethylene-octene copolymer and maleic anhydride grafted ethylene butyl acrylate.

[0018] Most preferably, the compatibilizer is maleic anhydride grafted ethylene butyl acrylate.

[0019] Preferably, the surface modifier is selected from at least one of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctylpyrophosphate) titanate.

[0020] Most preferably, the surface modifier consists of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctylpyrophosphate) titanate.

[0021] More preferably, the weight ratio of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctylpyrophosphate) titanate is 1-3:1-3:2-4.

[0022] Most preferably, the weight ratio of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctylpyrophosphate) titanate is 3:2:2.

[0023] The inventors surprisingly found in the research that the surface modifier of the present invention has an important influence on the smoke density of the prepared composite polypropylene insulation material; the composite polypropylene insulation material prepared by using the surface modifier composed of octamethylcyclotetrasiloxane, propyl trimethylsiloxane and isopropyl tri (dioctyl pyrophosphate acyloxy) titanate has a smoke density that is much lower than the composite polypropylene insulation material prepared by using a single octamethylcyclotetrasiloxane, propyl trimethylsiloxane or isopropyl tri (dioctyl pyrophosphate acyloxy) as the surface modifier. At the same time, the three components of octamethylcyclotetrasiloxane, propyl trimethylsiloxane and isopropyl tri (dioctyl pyrophosphate acyloxy) titanate can be used as surface modifiers to synergistically reduce the smoke density of the prepared composite polypropylene insulation material.

[0024] Preferably, the nitrogen-based flame retardant is selected from at least one of melamine cyanurate, melamine pyrophosphate and melamine polyphosphate.

[0025] Most preferably, the nitrogen-based flame retardant is melamine cyanurate.

[0026] Preferably, the phosphorus-based flame retardant is selected from at least one of diethyl aluminum hypophosphite, aluminum hypophosphite, piperazine pyrophosphate and polyphosphate.

[0027] Most preferably, the phosphorus-based flame retardant is aluminum hypophosphite.

[0028] Preferably, the smoke suppressant is selected from at least one of aluminum hydroxide, magnesium hydroxide, zinc borate and montmorillonite.

[0029] Most preferably, the smoke suppressant is montmorillonite.

[0030] Preferably, the antioxidant is selected from at least one of hindered phenol antioxidants and phosphite antioxidants.

[0031] Further preferably, the hindered phenol antioxidant is selected from at least one of antioxidants 245, 264, 300, 702, 703, 1010, 1024, B215, B225, B900, B911, DLTDP and DSTDP.

[0032] Further preferably, the phosphite antioxidant is selected from at least one of antioxidants 168, 626 and P-EPQ.

[0033] Still more preferably, the antioxidant is prepared by mixing DSTDP:168:1024 in a mass ratio of 3:1.5:1.

[0034] The present invention also provides a method for preparing the composite polypropylene insulating material, which comprises the following steps:

[0035] Adding the surface modifier to the resin composition containing polypropylene by spraying, and stirring evenly after the spraying is completed to obtain a mixture A;

[0036] The antioxidant, the smoke suppressant, the phosphorus flame retardant, and the nitrogen flame retardant are uniformly stirred to obtain a mixture B;

[0037] Mixture A and mixture B are stirred evenly to obtain mixture C;

[0038] The mixture C is extruded and granulated by a twin-screw extruder to obtain the composite polypropylene insulating material.

[0039] The present invention also provides a use of the composite polypropylene insulating material in preparing low-voltage cables in a cabin of an aircraft.

[0040] Beneficial effects: The present invention provides a new composite polypropylene insulating material, which has excellent halogen-free flame retardant properties, low smoke, low toxicity, and excellent high and low temperature resistance; it can meet the requirements of the CCAR-25-R4 standard for smoke density and smoke toxicity of cable materials, and also meets the C-level temperature resistance requirements of the ISO 19642 standard for automotive wires; it is a composite polypropylene insulating material with excellent comprehensive performance, suitable for use as an insulating layer for low-voltage cables in aircraft cabins; in addition, the composite polypropylene insulating material described in the present invention has a simple preparation process and is worthy of popularization and application. DETAILED DESCRIPTION

[0041] The present invention is further explained below in conjunction with specific examples, but the examples do not limit the present invention in any form.

[0042] In the following examples, the polypropylene resin used is polypropylene with a brand name of Z30S from Sinopec; the SEBS resin used is SEBS resin with a brand name of 1659 from Kraton; the ethylene-octene copolymer used is ethylene-octene copolymer with a brand name of 8150 from Dow; the PPO resin used is PPO resin with a brand name of 040C from Bluestar; and the maleic anhydride grafted ethylene butyl acrylate used is maleic anhydride grafted ethylene butyl acrylate with a brand name of BA3210 from Arkema. Other raw materials not specified are all conventional raw materials that can be purchased by those skilled in the art.

[0043] Example 1 Preparation of composite polypropylene insulation material

[0044] The raw materials are composed in parts by weight: 35 parts of polypropylene resin; 10 parts of SEBS resin; 10 parts of elastomer resin; 10 parts of PPO resin; 5 parts of compatibilizer; 1 part of surface modifier; 15 parts of nitrogen flame retardant; 15 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0045] The elastomer resin is ethylene-octene copolymer; the compatibilizer is maleic anhydride grafted ethylene butyl acrylate; the nitrogen flame retardant is melamine cyanurate; the phosphorus flame retardant is aluminum hypophosphite; the smoke suppressant is montmorillonite;

[0046] The antioxidant is composed of DSTDP, 168 and 1024 in a mass ratio of 3:1.5:1;

[0047] The surface modifier is composed of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctyl pyrophosphate acyloxy) titanate in a weight ratio of 3:2:2.

[0048] Preparation method of composite polypropylene insulation material:

[0049] (1) adding a surface modifier to a mixed resin by spraying, and continuing to stir for 3 minutes after the spraying is completed to obtain a mixture A; the mixed resin is a mixture of polypropylene resin, SEBS resin, elastomer resin and PPO resin;

[0050] (2) stirring the antioxidant, smoke suppressant, phosphorus flame retardant, and nitrogen flame retardant for 5 minutes to obtain a mixture B;

[0051] (3) stirring mixture A and mixture B for 5 minutes to obtain mixture C;

[0052] (4) Extruding the mixture C through a twin-screw extruder to form granules, thereby obtaining the composite polypropylene insulating material.

[0053] Example 2 Preparation of composite polypropylene insulation material

[0054] The raw materials are composed by weight: 35 parts of polypropylene resin; 15 parts of SEBS resin; 5 parts of elastomer resin; 10 parts of PPO resin; 5 parts of compatibilizer; 1.5 parts of surface modifier; 20 parts of nitrogen flame retardant; 10 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0055] The elastomer resin is ethylene-octene copolymer; the compatibilizer is maleic anhydride grafted ethylene butyl acrylate; the nitrogen flame retardant is melamine cyanurate; the phosphorus flame retardant is aluminum hypophosphite; the smoke suppressant is montmorillonite;

[0056] The antioxidant is composed of DSTDP, 168 and 1024 in a mass ratio of 3:1.5:1;

[0057] The surface modifier is composed of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctyl pyrophosphate acyloxy) titanate in a weight ratio of 3:2:2.

[0058] The preparation method of the composite polypropylene insulating material is the same as that of Example 1.

[0059] Example 3 Preparation of composite polypropylene insulation material

[0060] The raw materials are composed by weight: 30 parts of polypropylene resin, 10 parts of SEBS resin, 15 parts of elastomer resin, 5 parts of PPO resin, 5 parts of compatibilizer, 0.5 parts of surface modifier, 20 parts of nitrogen flame retardant, 15 parts of phosphorus flame retardant, 5 parts of smoke suppressant and 0.8 parts of antioxidant.

[0061] The elastomer resin is ethylene-octene copolymer; the compatibilizer is maleic anhydride grafted ethylene butyl acrylate; the nitrogen flame retardant is melamine cyanurate; the phosphorus flame retardant is aluminum hypophosphite; the smoke suppressant is montmorillonite;

[0062] The antioxidant is composed of DSTDP, 168 and 1024 in a mass ratio of 3:1.5:1;

[0063] The surface modifier is composed of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctyl pyrophosphate acyloxy) titanate in a weight ratio of 3:2:2.

[0064] The preparation method of the composite polypropylene insulating material is the same as that of Example 1.

[0065] Example 4 Preparation of composite polypropylene insulation material

[0066] The raw materials are composed in parts by weight: 40 parts of polypropylene resin; 5 parts of SEBS resin; 10 parts of elastomer resin; 5 parts of PPO resin; 10 parts of compatibilizer; 1.2 parts of surface modifier; 20 parts of nitrogen flame retardant; 10 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0067] The raw materials are composed by weight: 35 parts of polypropylene resin; 15 parts of SEBS resin; 5 parts of elastomer resin; 10 parts of PPO resin; 5 parts of compatibilizer; 1.5 parts of surface modifier; 20 parts of nitrogen flame retardant; 10 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0068] The elastomer resin is ethylene-octene copolymer; the compatibilizer is maleic anhydride grafted ethylene butyl acrylate; the nitrogen flame retardant is melamine cyanurate; the phosphorus flame retardant is aluminum hypophosphite; the smoke suppressant is montmorillonite;

[0069] The antioxidant is composed of DSTDP, 168 and 1024 in a mass ratio of 3:1.5:1;

[0070] The surface modifier is composed of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctyl pyrophosphate acyloxy) titanate in a weight ratio of 3:2:2.

[0071] The preparation method of the composite polypropylene insulating material is the same as that of Example 1.

[0072] Example 5 Preparation of composite polypropylene insulation material

[0073] The raw materials are composed in parts by weight: 35 parts of polypropylene resin; 10 parts of SEBS resin; 10 parts of elastomer resin; 10 parts of PPO resin; 5 parts of compatibilizer; 1 part of surface modifier; 15 parts of nitrogen flame retardant; 15 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0074] The elastomer resin is ethylene-octene copolymer; the compatibilizer is maleic anhydride grafted ethylene butyl acrylate; the nitrogen flame retardant is melamine cyanurate; the phosphorus flame retardant is aluminum hypophosphite; the smoke suppressant is montmorillonite;

[0075] The antioxidant is composed of DSTDP, 168 and 1024 in a mass ratio of 3:1.5:1;

[0076] The surface modifier is octamethylcyclotetrasiloxane.

[0077] Preparation method of composite polypropylene insulating material: same as Example 1.

[0078] The difference between Example 5 and Example 1 is that the surface modifier is only octamethylcyclotetrasiloxane.

[0079] Example 6 Preparation of composite polypropylene insulation material

[0080] The raw materials are composed in parts by weight: 35 parts of polypropylene resin; 10 parts of SEBS resin; 10 parts of elastomer resin; 10 parts of PPO resin; 5 parts of compatibilizer; 1 part of surface modifier; 15 parts of nitrogen flame retardant; 15 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0081] The elastomer resin is ethylene-octene copolymer; the compatibilizer is maleic anhydride grafted ethylene butyl acrylate; the nitrogen flame retardant is melamine cyanurate; the phosphorus flame retardant is aluminum hypophosphite; the smoke suppressant is montmorillonite;

[0082] The antioxidant is composed of DSTDP, 168 and 1024 in a mass ratio of 3:1.5:1;

[0083] The surface modifier is propyl trimethylsiloxane.

[0084] Preparation method of composite polypropylene insulating material: same as Example 1.

[0085] The difference between Example 6 and Example 1 is that the surface modifier is only propyl trimethylsiloxane.

[0086] Example 7 Preparation of composite polypropylene insulation material

[0087] The raw materials are composed in parts by weight: 35 parts of polypropylene resin; 10 parts of SEBS resin; 10 parts of elastomer resin; 10 parts of PPO resin; 5 parts of compatibilizer; 1 part of surface modifier; 15 parts of nitrogen flame retardant; 15 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0088] The elastomer resin is ethylene-octene copolymer; the compatibilizer is maleic anhydride grafted ethylene butyl acrylate; the nitrogen flame retardant is melamine cyanurate; the phosphorus flame retardant is aluminum hypophosphite; the smoke suppressant is montmorillonite;

[0089] The antioxidant is composed of DSTDP, 168 and 1024 in a mass ratio of 3:1.5:1;

[0090] The surface modifier is isopropyl tri(dioctyl pyrophosphate acyloxy) titanate.

[0091] Preparation method of composite polypropylene insulating material: same as Example 1.

[0092] The difference between Example 7 and Example 1 is that the surface modifier is only isopropyl tri(dioctyl pyrophosphate) titanate.

[0093] Comparative Example 1 Preparation of composite polypropylene insulation material

[0094] The raw materials are composed by weight: 35 parts of polypropylene resin; 10 parts of SEBS resin; 10 parts of elastomer resin; 5 parts of compatibilizer; 1 part of surface modifier; 25 parts of nitrogen flame retardant; 15 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0095] Preparation method: refer to the preparation method described in Example 1.

[0096] The difference between Comparative Example 1 and Example 1 is that no PPO resin is added.

[0097] Comparative Example 2 Preparation of composite polypropylene insulation material

[0098] The raw materials are composed by weight: 35 parts of polypropylene resin; 10 parts of SEBS resin; 10 parts of elastomer resin; 10 parts of PPO resin; 1 part of surface modifier; 5 parts of compatibilizer; 15 parts of nitrogen flame retardant; 20 parts of phosphorus flame retardant; and 0.8 parts of antioxidant.

[0099] Preparation method: refer to the preparation method described in Example 1.

[0100] The difference between Comparative Example 2 and Example 1 is that no smoke suppressant is added.

[0101] Comparative Example 3 Preparation of composite polypropylene insulation material

[0102] The raw materials are composed by weight: 55 parts of polypropylene resin; 10 parts of PPO resin; 5 parts of compatibilizer; 1 part of surface modifier; 15 parts of nitrogen flame retardant; 15 parts of phosphorus flame retardant; 5 parts of smoke suppressant; and 0.8 parts of antioxidant.

[0103] Preparation method: refer to the preparation method described in Example 1.

[0104] The difference between Comparative Example 3 and Example 1 is that SEBS resin and elastomer resin are not added; only polypropylene resin and PPO resin are used instead.

[0105] Table 1 Composite polypropylene insulation material performance test results

[0106]

[0107]

[0108] In Table 1, -40℃ low temperature winding, 125℃ / 3000h long term heat aging and 150℃ / 240h short term heat aging are tested in accordance with ISO 19642 standard requirements; 60° flame retardancy, smoke density and smoke toxicity are tested in accordance with the relevant requirements for cables in CCAR-25-R4 standard.

[0109] It can be seen from the experimental results in Table 1 that the composite polypropylene insulation materials prepared in Examples 1 to 7 have flame retardant properties, high and low temperature resistance, smoke density, smoke toxicity and other properties that all meet the requirements of ISO 19642 and CCAR-25-R4 standards; and can meet the requirements of low-voltage cables in the cabin of an aircraft.

[0110] It can also be seen from the experimental results in Table 1 that the flame retardant properties and smoke toxicity of the composite polypropylene insulation material prepared in Comparative Example 1 do not meet the standard requirements; the low temperature resistance of the composite polypropylene insulation material prepared in Comparative Example 3 does not meet the standard requirements. It can be seen that the selection of resins in the present invention is very important; the composite polypropylene insulation material prepared by a resin combination consisting of four resins, namely, polypropylene resin, SEBS resin, elastomer resin and PPO resin, must be selected at the same time, so that its flame retardant properties, high and low temperature resistance, smoke density and smoke toxicity can all meet the standard requirements, and the prepared composite polypropylene insulation material can meet the requirements of low-voltage cables in the cabin of the aircraft.

[0111] It can also be seen from the experimental results in Table 1 that the smoke density of the composite polypropylene insulation material prepared in Example 1 is much lower than that of the composite polypropylene insulation material prepared in Examples 5 to 7; this shows that the surface modifier of the present invention has an important influence on the smoke density of the composite polypropylene insulation material prepared; the composite polypropylene insulation material prepared by using the surface modifier composed of octamethylcyclotetrasiloxane, propyl trimethylsiloxane and isopropyl tri (dioctyl pyrophosphate acyloxy) titanate has a smoke density much lower than that of the composite polypropylene insulation material prepared by using a single octamethylcyclotetrasiloxane, propyl trimethylsiloxane or isopropyl tri (dioctyl pyrophosphate acyloxy) as the surface modifier. At the same time, the three components of octamethylcyclotetrasiloxane, propyl trimethylsiloxane and isopropyl tri (dioctyl pyrophosphate acyloxy) titanate are selected as surface modifiers to synergistically reduce the smoke density of the composite polypropylene insulation material prepared.

Claims

1. A composite polypropylene insulating material, characterized in that: The invention comprises the following components in parts by weight: 30 to 100 parts of a resin composition containing polypropylene; 0 to 10 parts of a compatibilizer; 0.5 to 1.5 parts of a surface modifier; 15 to 25 parts of a nitrogen-based flame retardant; 10 to 15 parts of a phosphorus-based flame retardant; 0 to 5 parts of a smoke suppressant; and 0.5 to 1 part of an antioxidant.

2. The composite polypropylene insulating material according to claim 1, characterized in that: The polypropylene-containing resin composition comprises polypropylene resin, SEBS resin, elastomer resin and PPO resin.

3. The composite polypropylene insulating material according to claim 1, characterized in that: The compatibilizer is selected from at least one of maleic anhydride grafted polypropylene, maleic anhydride grafted ethylene-vinyl acetate copolymer, maleic anhydride grafted ethylene-octene copolymer and maleic anhydride grafted ethylene butyl acrylate.

4. The composite polypropylene insulating material according to claim 1, characterized in that: The surface modifier is selected from at least one of octamethylcyclotetrasiloxane, propyltrimethylsiloxane and isopropyl tri(dioctylpyrophosphate) titanate.

5. The composite polypropylene insulating material according to claim 1, characterized in that: The nitrogen-based flame retardant is selected from at least one of melamine cyanurate, melamine pyrophosphate and melamine polyphosphate.

6. The composite polypropylene insulating material according to claim 1, characterized in that: The phosphorus-based flame retardant is selected from at least one of diethyl aluminum hypophosphite, aluminum hypophosphite, piperazine pyrophosphate and polyphosphate.

7. The composite polypropylene insulating material according to claim 1, characterized in that: The smoke suppressant is selected from at least one of aluminum hydroxide, magnesium hydroxide, zinc borate and montmorillonite.

8. The composite polypropylene insulating material according to claim 1, characterized in that: The antioxidant is selected from at least one of hindered phenol antioxidants and phosphite antioxidants.

9. The method for preparing the composite polypropylene insulating material according to any one of claims 1 to 8, characterized in that: The following steps are included: Adding the surface modifier to the resin composition containing polypropylene by spraying, and stirring evenly after the spraying is completed to obtain a mixture A; The antioxidant, the smoke suppressant, the phosphorus flame retardant, and the nitrogen flame retardant are uniformly stirred to obtain a mixture B; Mixture A and mixture B are stirred evenly to obtain mixture C; The mixture C is extruded and granulated by a twin-screw extruder to obtain the composite polypropylene insulating material.

10. Use of the composite polypropylene insulating material according to any one of claims 1 to 8 in the preparation of low-voltage cables in aircraft cabins.

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