A special cable compound for low-smoke and halogen-free new energy wire and cable materials, its preparation and application

Abstract

The present invention relates to a special cable material for low-smoke and halogen-free new energy wire and cable, which is prepared from raw materials comprising the following components and their weight parts: 40-50 parts of ethylene-vinyl acetate copolymer, 15-25 parts of linear low-density polyethylene, 4-8 parts of thermoplastic acrylic resin, 6-10 parts of compatibilizer, 35-60 parts of composite flame retardant, 1-4 parts of antioxidant, 2-3 parts of crosslinking agent, 0.5-1 part of coupling agent and 1-2 parts of stabilizer. Compared with the prior art, the preparation process of the cable material of the present invention is simple, has good molding processability, has excellent oil resistance and corrosion resistance, good weather resistance, good flame retardant and smoke suppression effects, and has good mechanical strength and toughness. When used as the cable material of new energy equipment, it has a long service life, is safe and reliable, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of wire and cable, and relates to a special cable material for low-smoke and halogen-free new energy wire and cable, its preparation and application. Background Art

[0002] In today's society, it is at a stage with a huge demand for energy consumption. With the continuous deepening of the global energy crisis, the increasing depletion of oil resources, and the exacerbation of the hazards of air pollution and rising global temperatures, the need for low-carbon and environmental protection is being taken more and more seriously by people. Governments and automobile enterprises around the world generally recognize that energy conservation and emission reduction are the main directions for the future development of automotive technology. As a new generation of transportation means, electric vehicles have incomparable advantages over traditional vehicles in terms of energy conservation and emission reduction and reducing human dependence on traditional fossil energy.

[0003] At present, due to its specific use environment, the power cable wire for new energy electric vehicles needs to have good oil resistance, corrosion resistance, and a wide working temperature to adapt to the changeable outdoor weather environment. It also needs to have excellent flame retardant properties to ensure the safety of long-term use of the wire. In terms of flame retardant properties, the traditional method is to add halogen-containing flame retardants. However, during the combustion process of such wire and cable, a large amount of smoke and hydrogen halide gas are released, which can cause people to suffocate to death in a fire and also have a greater corrosive effect on instruments and equipment, causing the so-called "secondary disaster". Summary of the Invention

[0004] An object of the present invention is to provide a special cable material for low-smoke and halogen-free new energy wire and cable with good molding processing stability, excellent oil resistance and corrosion resistance, and outstanding flame retardancy to overcome the defects of the above-mentioned existing technologies.

[0005] Another object of the present invention is to provide a preparation method of the special cable material for low-smoke and halogen-free new energy wire and cable.

[0006] Still another object of the present invention is to provide the application of the special cable material for low-smoke and halogen-free new energy wire and cable.

[0007] The object of the present invention can be achieved by the following technical solutions:

[0008] According to one aspect of the present invention, there is provided a special cable material for low-smoke and halogen-free new energy wire and cable, which is prepared from raw materials comprising the following components and their weight fraction contents: 40-50 parts of ethylene-vinyl acetate copolymer, 15-25 parts of linear low-density polyethylene, 4-8 parts of thermoplastic acrylic resin, 6-10 parts of compatibilizer, 35-60 parts of composite flame retardant, 1-4 parts of antioxidant, 2-3 parts of crosslinking agent, 0.5-1 part of coupling agent, and 1-2 parts of stabilizer.

[0009] As an embodiment, the vinyl acetate content in the ethylene-vinyl acetate copolymer is 12-25 wt%, and its melt index is 8-20 g / 10 min (190 °C, 2.16 kg).

[0010] As an embodiment, the melt index of the linear low density polyethylene is 30-50 g / 10 min (190 °C, 2.16 kg).

[0011] As an embodiment, the solid content of the thermoplastic acrylic resin is 50-52%, and the viscosity is 0.9-1.4 mPa·s.

[0012] As an embodiment, the compatibilizer is maleic anhydride grafted EVA, its grafting rate is 1.2%, and the melt index is 10-25 g / 10 min (190 °C, 2.16 kg).

[0013] As an embodiment, the antioxidant is selected from at least one of 2,6-di-tert-butyl-p-cresol, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)trimethylbenzene, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-dioctyldiphenylamine.

[0014] As an embodiment, the crosslinking agent is selected from one or more of bis(4-methylbenzoyl) peroxide, tert-butyl peroxy-2-ethylhexyl carbonate or 1,1-bis(tert-butylperoxy)cyclohexane.

[0015] As an embodiment, the coupling agent is selected from one or more of vinyltris(methoxyethoxy)silane, γ-(methacryloyloxy)propyltrimethoxysilane or vinyltriethoxysilane.

[0016] As an embodiment, the stabilizer is an organotin heat stabilizer, selected from at least one of dibutyltin maleate, dibutyltin dilaurate, dibutyltin maleate laurate, di-n-octyltin maleate, di-n-octyltin dilaurate or dioctyltin bis(thio glycolate isooctyl ester).

[0017] As an embodiment, the composite flame retardant is compounded from modified chitosan, microencapsulated red phosphorus, silicone and a flame retardant synergist in a mass ratio of 20-40:5:0.5-1:1-3.

[0018] As an embodiment, the modified chitosan is prepared by the following method:

[0019] Step i): Dissolve chitosan in an acetic acid aqueous solution with a concentration of 0.1 - 0.5 mol / L at 30 - 40°C, then raise the temperature to 80 - 95°C, carry out condensation reflux, slowly add formaldehyde, react for 1 - 2 h, then slowly add melamine, react for 2 - 4 h, and cool to room temperature to obtain an intermediate reaction solution;

[0020] Step ii): Prepare an aqueous solution of sodium pyrophosphate with a mass content of 10 - 20%, drop the aqueous solution of sodium pyrophosphate into the intermediate reaction solution prepared in step i), finish dropping within 5 - 10 min, continue to react for 1 - 2 h to form a precipitate, let it stand, filter, wash with water, dry, crush, and pass through a 500 - mesh sieve to obtain the modified chitosan.

[0021] Preferably, the mass concentration of chitosan in the acetic acid aqueous solution is 0.05 - 0.1 g / ml.

[0022] Preferably, the molar ratio of chitosan to formaldehyde and melamine is 5:1:1 - 2.

[0023] Preferably, the volume ratio of the aqueous solution of sodium pyrophosphate to the intermediate reaction solution is 1:1 - 1.5.

[0024] As an embodiment, the flame retardant synergist includes at least one of aluminum hydroxide, silicon dioxide, ammonium molybdate, manganese dioxide, or cobalt sesquioxide.

[0025] According to another aspect of the present invention, there is provided a method for preparing a low - smoke and halogen - free new - energy wire and cable special compound, including the following steps:

[0026] Step 1): Add each component by weight to an open two - roll plasticator for mixing, control the temperature of the front roll of the plasticator to be 140 - 150°C, and the temperature of the rear roll to be 150 - 160°C. After mixing evenly, transfer it to a mold;

[0027] Step 2): Heat the flat vulcanizer to 160 - 170°C, place the mold on the flat vulcanizer for pre - heating for 5 - 10 min to fully melt the material, exhaust 3 - 4 times, then increase the pressure to 8 - 10 MPa, keep the pressure for 3 - 5 min, then transfer the mold to another flat vulcanizer for cold pressing for 5 - 10 min, take out the mold, and then carry out demolding, lay flat and cool, and remove the flash to obtain the special compound for the cable.

[0028] According to yet another aspect of the present invention, there is provided an application of the low - smoke and halogen - free new - energy wire and cable special compound, using the above - mentioned cable compound for preparing new - energy electric vehicle wires and cables, charging pile wires and cables, outdoor power transmission cables, and electrical equipment wires and cables.

[0029] Compared with the prior art, the present invention has the following characteristics:

[0030] 1) The present invention uses a blend of ethylene-vinyl acetate copolymer and linear low density polyethylene as the main base material. The introduction of linear low density polyethylene is beneficial to improving the acid, alkali and organic solvent resistance of the base material. A crosslinking agent is used to bind thermoplastic acrylic resin to the base resin through a crosslinking reaction, which can effectively improve the light aging resistance and weather resistance of the final material system, is beneficial to enhancing the flexibility of the final material system, and endows the final material system with excellent environmental stress cracking resistance.

[0031] 2) In order to improve the flame retardancy of the cable compound, the present invention blends modified chitosan, microencapsulated red phosphorus, silicone and a flame retardant synergist to form a highly efficient halogen-free flame retardant. The modified chitosan used therein is based on chitosan, and melamine pyrophosphate is organically combined into chitosan to form an environmentally friendly intumescent flame retardant component containing N and P elements. It has excellent thermal stability and good combustion smoke suppression effect. It can cooperate with microencapsulated red phosphorus and the flame retardant synergist to play a synergistic effect. It can promote the carbonization process under high temperature conditions, is conducive to forming a dense and stable carbon layer, can delay and avoid the combustion of internal materials, can effectively reduce the smoke release amount, and has prominent flame retardant effect. The use of modified chitosan can also improve the compatibility of the flame retardant system in the base resin, which is not only beneficial to maintaining the mechanical properties of the material system, but also can effectively inhibit the occurrence of the melting drop phenomenon.

[0032] 3) The preparation process of the cable compound of the present invention is simple, has good molding processability, has excellent oil resistance and corrosion resistance, good weather resistance, good flame retardant and smoke suppression effects, and has both good mechanical strength and toughness. Used as the cable material for new energy equipment, it has a long service life, is safe and reliable, and has good application prospects. Embodiment

[0033] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. These embodiments are implemented on the premise of the technical solutions of the present invention, and detailed implementation manners and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0034] In this article, when the term "about" is used to modify a numerical value, it means an error tolerance measured within ±5% of that numerical value.

[0035] The theories or mechanisms described and disclosed in this article, whether right or wrong, should not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0036] The present invention will be described in detail below in conjunction with specific embodiments.

[0037] Example 1:

[0038] The low-smoke halogen-free new energy wire and cable special compound for this example is prepared from raw materials containing the following components and their weight fraction contents: 40 parts of ethylene-vinyl acetate copolymer, 15 parts of linear low-density polyethylene, 4 parts of thermoplastic acrylic resin, 6 parts of compatibilizer, 35 parts of composite flame retardant, 1 part of antioxidant, 2 parts of crosslinking agent, 0.5 part of coupling agent, and 1 part of stabilizer.

[0039] Among the raw material components used in this example:

[0040] The vinyl acetate content in the ethylene-vinyl acetate copolymer is 12 wt%, and its melt index is 8 g / 10min (190 °C, 2.16 kg);

[0041] The melt index of the linear low-density polyethylene is 30 g / 10min (190 °C, 2.16 kg);

[0042] The solid content of the thermoplastic acrylic resin is 50%, and the viscosity is 0.9 mPa·s;

[0043] The compatibilizer is maleic anhydride grafted EVA, its grafting rate is 1.2%, and the melt index is 2 g / 10min (190 °C, 2.16 kg);

[0044] The antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate;

[0045] The crosslinking agent is bis(4-methylbenzoyl) peroxide;

[0046] The coupling agent is vinyltris(methoxyethoxy)silane;

[0047] The stabilizer is dibutyltin maleate;

[0048] The composite flame retardant is compounded from modified chitosan, microencapsulated red phosphorus, silicone, and a flame retardant synergist in a mass ratio of 20:5:0.5:1, where the flame retardant synergist is aluminum hydroxide; the modified chitosan is prepared by the following method:

[0049] Step i): Dissolve chitosan in 0.1 mol / L acetic acid aqueous solution at 30 °C, then heat up to 80 °C, carry out condensation reflux, slowly add formaldehyde, react for 2 h, then slowly add melamine, react for 4 h, and cool to room temperature to obtain an intermediate reaction solution;

[0050] Step ii): Prepare an aqueous solution of sodium pyrophosphate with a mass content of 10%, and drop the aqueous solution of sodium pyrophosphate into the intermediate reaction solution obtained in step i). Finish dropping within 5 minutes, and continue the reaction for 1 hour to form a precipitate. Let it stand, filter, wash with water, dry, pulverize, and pass through a 500-mesh sieve to obtain modified chitosan.

[0051] In the above method for preparing modified chitosan, the mass concentration of chitosan in the aqueous acetic acid solution is 0.05 g / ml, the molar ratio of chitosan to formaldehyde and melamine is 5:1:1, and the volume ratio of the aqueous sodium pyrophosphate solution to the intermediate reaction solution is 1:1.

[0052] Example 2:

[0053] The low-smoke halogen-free new energy wire and cable special material of this example is prepared from raw materials including the following components and their weight parts: 50 parts of ethylene-vinyl acetate copolymer, 25 parts of linear low-density polyethylene, 8 parts of thermoplastic acrylic resin, 10 parts of compatibilizer, 60 parts of composite flame retardant, 4 parts of antioxidant, 3 parts of crosslinking agent, 1 part of coupling agent, and 2 parts of stabilizer.

[0054] Among the raw material components used in this example:

[0055] The vinyl acetate content in the ethylene-vinyl acetate copolymer is 25 wt%, and its melt index is 20 g / 10min (190 °C, 2.16 kg);

[0056] The melt index of linear low-density polyethylene is 50 g / 10min (190 °C, 2.16 kg);

[0057] The solid content of the thermoplastic acrylic resin is 52%, and the viscosity is 1.4 mPa·s;

[0058] The compatibilizer is maleic anhydride grafted EVA, its grafting rate is 1.8%, and the melt index is 5 g / 10min (190 °C, 2.16 kg);

[0059] The antioxidant is 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane;

[0060] The crosslinking agent is tert-butyl peroxy-2-ethylhexyl carbonate;

[0061] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0062] The stabilizer is dibutyltin dilaurate;

[0063] The composite flame retardant is prepared by compounding modified chitosan, microencapsulated red phosphorus, silicone and a flame retardant synergist in a mass ratio of 40:5:1:3, wherein the flame retardant synergist is prepared by mixing aluminum hydroxide and ammonium molybdate in a mass ratio of 4:1; the modified chitosan is prepared by the following method:

[0064] Step i): Dissolve chitosan in 0.5 mol / L acetic acid aqueous solution at 40 °C, then raise the temperature to 95 °C, carry out condensation reflux, slowly add formaldehyde, react for 1 h, then slowly add melamine, react for 2 h, and cool to room temperature to obtain an intermediate reaction solution;

[0065] Step ii): Prepare an aqueous solution of sodium pyrophosphate with a mass content of 20%, drop the aqueous solution of sodium pyrophosphate into the intermediate reaction solution prepared in step i), finish dropping within 10 min, continue to react for 2 h to form a precipitate, stand still, filter, wash with water, dry, pulverize, and pass through a 500-mesh sieve to obtain the modified chitosan.

[0066] In the above method for preparing modified chitosan, the mass concentration of chitosan in the acetic acid aqueous solution is 0.1 g / ml, the molar ratio of chitosan to formaldehyde and melamine is 5:1:2, and the volume ratio of the aqueous solution of sodium pyrophosphate to the intermediate reaction solution is 1:1.5.

[0067] Example 3:

[0068] The special cable material for low-smoke and halogen-free new energy wire and cable in this example is prepared from raw materials containing the following components and their weight parts: 46 parts of ethylene-vinyl acetate copolymer, 24 parts of linear low-density polyethylene, 6 parts of thermoplastic acrylic resin, 8 parts of compatibilizer, 46 parts of composite flame retardant, 2 parts of antioxidant, 2.5 parts of crosslinking agent, 0.7 part of coupling agent, and 1.8 parts of stabilizer.

[0069] Among the raw material components used in this example:

[0070] The vinyl acetate content in the ethylene-vinyl acetate copolymer is 18 wt%, and its melt index is 11 g / 10min (190 °C, 2.16 kg);

[0071] The melt index of the linear low-density polyethylene is 36 g / 10min (190 °C, 2.16 kg);

[0072] The solid content of the thermoplastic acrylic resin is 51%, and the viscosity is 1.2 mPa·s;

[0073] The compatibilizer is maleic anhydride grafted EVA, its grafting rate is 1.4%, and its melt index is 3 g / 10min (190 °C, 2.16 kg);

[0074] The antioxidant is a mixture of 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane and 4,4'-di-tert-octyldiphenylamine in a mass ratio of 4:1;

[0075] The crosslinking agent is 1,1-bis(tert-butylperoxy)cyclohexane;

[0076] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0077] The stabilizer is a mixture of bis(isooctyl thioglycolate)dioctyltin and dioctyltin dilaurate in a mass ratio of 1:1;

[0078] The composite flame retardant is prepared by compounding modified chitosan, microencapsulated red phosphorus, silicone and a flame retardant synergist in a mass ratio of 35:5:0.8:2, wherein the flame retardant synergist is a mixture of silicon dioxide, ammonium molybdate and cobalt(II) oxide in a mass ratio of 2:2:1; The modified chitosan is prepared by the following method:

[0079] Step i): Dissolve chitosan in 0.4 mol / L acetic acid aqueous solution at 35 °C, then raise the temperature to 92 °C, carry out condensation reflux, slowly add formaldehyde, react for 2 h, then slowly add melamine, react for 3 h, and cool to room temperature to obtain an intermediate reaction solution;

[0080] Step ii): Prepare an aqueous solution of sodium pyrophosphate with a mass content of 16%, drop the aqueous solution of sodium pyrophosphate into the intermediate reaction solution prepared in step i), finish dropping within 8 min, continue to react for 1.5 h, generate a precipitate, stand still, filter, wash with water, dry, pulverize, and pass through a 500-mesh sieve to obtain the modified chitosan.

[0081] In the above method for preparing modified chitosan, the mass concentration of chitosan in the acetic acid aqueous solution is 0.08 g / ml, the molar ratio of chitosan to formaldehyde and melamine is 5:1:1.5, and the volume ratio of the aqueous solution of sodium pyrophosphate to the intermediate reaction solution is 1:1.2.

[0082] Example 4:

[0083] The special cable material for low-smoke halogen-free new energy wire and cable in this example is prepared from raw materials containing the following components and their weight parts: 42 parts of ethylene-vinyl acetate copolymer, 18 parts of linear low-density polyethylene, 5 parts of thermoplastic acrylic resin, 7 parts of compatibilizer, 53 parts of composite flame retardant, 3 parts of antioxidant, 2.8 parts of crosslinking agent, 0.5 part of coupling agent and 1.7 parts of stabilizer.

[0084] Among the raw material components used in this example:

[0085] The vinyl acetate content in the ethylene-vinyl acetate copolymer is 22 wt%, and its melt index is 18 g / 10 min (at 190 °C, 2.16 kg);

[0086] The melt index of linear low-density polyethylene is 42 g / 10 min (at 190 °C, 2.16 kg);

[0087] The solid content of the thermoplastic acrylic resin is 50%, and the viscosity is 0.9 mPa·s;

[0088] The compatibilizer is maleic anhydride-grafted EVA, with a grafting rate of 1.4% and a melt index of 3 g / 10 min (at 190 °C, 2.16 kg);

[0089] The antioxidant is a mixture of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)trimethylbenzene and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) in a mass ratio of 2:1;

[0090] The crosslinking agent is tert-butyl peroxy-2-ethylhexyl carbonate;

[0091] The coupling agent is vinyltriethoxysilane;

[0092] The stabilizer is di-n-octyltin maleate;

[0093] The composite flame retardant is compounded from modified chitosan, microencapsulated red phosphorus, silicone, and a flame retardant synergist in a mass ratio of 30:5:0.6:2, where the flame retardant synergist is ammonium molybdate; the modified chitosan is prepared by the following method:

[0094] Step i): Dissolve chitosan in 0.2 mol / L acetic acid aqueous solution at 35 °C, then raise the temperature to 86 °C, carry out condensation reflux, slowly add formaldehyde, react for 1.5 h, then slowly add melamine, react for 4 h, and cool to room temperature to obtain an intermediate reaction solution;

[0095] Step ii): Prepare an aqueous solution of sodium pyrophosphate with a mass content of 12%, drop the sodium pyrophosphate aqueous solution into the intermediate reaction solution prepared in step i), finish dropping within 10 min, continue to react for 2 h to form a precipitate, let it stand, filter, wash with water, dry, pulverize, and pass through a 500-mesh sieve to obtain the modified chitosan.

[0096] In the above method for preparing modified chitosan, the mass concentration of chitosan in the acetic acid aqueous solution is 0.06 g / ml, the molar ratio of chitosan to formaldehyde and melamine is 5:1:2, and the volume ratio of the sodium pyrophosphate aqueous solution to the intermediate reaction solution is 1:1.

[0097] Preparation of Cable Compound

[0098] The cable compounds of the above Examples 1-4 are prepared by the following method:

[0099] Step 1): Add each component by weight to an open two-roll mill for mixing. Control the temperature of the front roll of the mill at 140-150 °C (for example, 140 °C in Example 1, 142 °C in Example 2, 150 °C in Example 3, and 146 °C in Example 4), and the temperature of the rear roll at 150-160 °C (for example, 150 °C in Example 1, 154 °C in Example 2, 158 °C in Example 3, and 160 °C in Example 4). After mixing evenly, transfer to a mold.

[0100] Step 2): Heat the flat vulcanizer to 160-170 °C (for example, 160 °C in Example 1, 165 °C in Example 2, and 170 °C in Examples 3-4). Place the mold on the flat vulcanizer for preheating for 5-10 min (for example, 10 min in Examples 1-2, 8 min in Example 3, and 5 min in Example 4) to fully melt the material. After exhausting 4 times, increase the pressure to 8-10 MPa (for example, 8 MPa in Examples 1-2, 9 MPa in Example 3, and 10 MPa in Example 4), and keep the pressure for 3-5 min (for example, 5 min in Examples 1-2, 4 min in Example 3, and 3 min in Example 4). Then transfer the mold to another flat vulcanizer for cold pressing for 5-10 min (for example, 10 min in Examples 1-2, 8 min in Example 3, and 5 min in Example 4). Take out the mold, and then through demolding, laying flat for cooling, and removing flash, the cable compound is obtained.

[0101] Comparative Example 1:

[0102] In the raw materials of the cable compound of this comparative example, ordinary commercially available chitosan is used to replace the modified chitosan, and the rest is the same as in Example 3.

[0103] Comparative Example 2:

[0104] In the raw materials of the cable compound of this comparative example, microencapsulated red phosphorus, silicone, and a flame retardant synergist are compounded as a flame retardant in a mass ratio of 5:0.8:2, and the rest is the same as in Example 3.

[0105] Comparative Example 3:

[0106] In the raw materials of the cable compound of this comparative example, the thermoplastic acrylic resin and the crosslinking agent are not included, and the rest is the same as in Example 3.

[0107] Performance Testing

[0108] The following performance tests are carried out on the cable compounds prepared in Examples 1-4 and Comparative Examples 1-3:

[0109] The oxygen index is tested according to the method in GB / T 2406-2008 "Determination of Flammability by Oxygen Index for Plastics"; the corresponding standard value is ≥32 according to the standard in JB / T10707-2007;

[0110] The tensile strength is tested according to the method in GB / T 1040-92 "Test Method for Tensile Properties of Plastics"; the corresponding standard value ≥9.0 according to the corresponding standard in JB / T 10707-2007;

[0111] The elongation at break is tested according to the method in GB / T 1040.2-92 "Test Method for Tensile Properties of Plastics". The test results are shown in Table 1 below.

[0112]

[0113] The cable materials prepared in the above Examples 1-4 can be used to prepare electric wires and cables for new energy electric vehicles, charging piles, outdoor power transmission cables, and electric wires and cables for electrical equipment.

[0114] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A special cable material for low-smoke and halogen-free new energy wire and cable, characterized in that, It is prepared from raw materials comprising the following components and their weight parts: 40 - 50 parts of ethylene - vinyl acetate copolymer, 15 - 25 parts of linear low - density polyethylene, 4 - 8 parts of thermoplastic acrylic resin, 6 - 10 parts of compatibilizer, 35 - 60 parts of composite flame retardant, 1 - 4 parts of antioxidant, 2 - 3 parts of cross - linker, 0.5 - 1 part of coupling agent and 1 - 2 parts of stabilizer; The composite flame retardant is compounded from modified chitosan, micro - encapsulated red phosphorus, silicone and flame retardant synergist in a mass ratio of 20 - 40:5:0.5 - 1:1 - 3; The modified chitosan is prepared by the following method: Step i): Dissolve chitosan in 0.1 - 0.5 mol / L acetic acid aqueous solution at 30 - 40 °C, then raise the temperature to 80 - 95 °C, carry out condensation reflux, slowly add formaldehyde, react for 1 - 2 h, then slowly add melamine, react for 2 - 4 h, and cool to room temperature to obtain an intermediate reaction solution; Step ii): Prepare an aqueous solution of sodium pyrophosphate with a mass content of 10 - 20%, drop the aqueous solution of sodium pyrophosphate into the intermediate reaction solution prepared in step i), finish dropping within 5 - 10 min, continue to react for 1 - 2 h to form a precipitate, stand, filter, wash with water, dry, pulverize, and pass through a 500 - mesh sieve to obtain the modified chitosan; The mass concentration of chitosan in the acetic acid aqueous solution is 0.05 - 0.1 g / ml; The molar ratio of chitosan to formaldehyde and melamine is 5:1:1 - 2; The volume ratio of the aqueous solution of sodium pyrophosphate to the intermediate reaction solution is 1:1 - 1.5; The flame retardant synergist includes at least one of aluminum hydroxide, silicon dioxide, ammonium molybdate, manganese dioxide or cobalt sesquioxide.

2. The special cable material for low-smoke and halogen-free new energy wire and cable according to claim 1, characterized in that, The vinyl acetate content in the ethylene - vinyl acetate copolymer is 12 - 25 wt%, and its melt index at 190 °C and 2.16 kg is 8 - 20 g / 10 min.

3. The special cable material for low-smoke and halogen-free new energy wire and cable according to claim 1, characterized in that, The melt index of the linear low - density polyethylene at 190 °C and 2.16 kg is 30 - 50 g / 10 min.

4. The special cable material for low-smoke and halogen-free new energy wire and cable according to claim 1, characterized in that, The solid content of the thermoplastic acrylic resin is 50 - 52%, and the viscosity is 0.9 - 1.4 mPa·s.

5. The special cable material for low-smoke and halogen-free new energy wire and cable according to claim 1, characterized in that, The compatibilizer is maleic anhydride - grafted EVA, its grafting rate is 1.2%, and its melt index at 190 °C and 2.16 kg is 10 - 25 g / 10 min; The antioxidant is selected from at least one of 2,6 - di - tert - butyl - p - cresol, octadecyl 3,5 - di - tert - butyl - 4 - hydroxybenzoate, 1,1,3 - tris(2 - methyl - 4 - hydroxy - 5 - tert - butylphenyl)butane, 2,2'-methylenebis(4 - ethyl - 6 - tert - butylphenol), 1,3,5 - tris(3,5 - di - tert - butyl - 4 - hydroxybenzyl)trimethylbenzene, 2,2'-methylenebis(4 - methyl - 6 - tert - butylphenol), 4,4'-dioctyldiphenylamine; The cross - linker is selected from one or more of bis(4 - methylbenzoyl) peroxide, tert - butyl peroxy - 2 - ethylhexyl carbonate or 1,1 - bis(tert - butylperoxy)cyclohexane; The coupling agent is selected from one or more of vinyltris(methoxyethoxy)silane, γ-(methacryloyloxy)propyltrimethoxysilane, or vinyltriethoxysilane; The stabilizer is an organotin heat stabilizer, selected from at least one of dibutyltin maleate, dibutyltin dilaurate, dibutyltin maleate laurate, di-n-octyltin maleate, di-n-octyltin dilaurate, or dioctyltin bis(thio glycolate isooctyl ester).

6. The preparation method of the special cable material for low-smoke and halogen-free new energy wire and cable according to any one of claims 1 to 5, characterized in that, It includes the following steps: Step 1): Add each component by weight to an open two-roll mill for mixing. Control the temperature of the front roll of the mill at 140 - 150 °C and the temperature of the rear roll at 150 - 160 °C. After mixing evenly, transfer it to a mold; Step 2): Heat the flat vulcanizer to 160 - 170 °C, place the mold on the flat vulcanizer for preheating for 5 - 10 min to fully melt the material. After exhausting 3 - 4 times, increase the pressure to 8 - 10 MPa, hold the pressure for 3 - 5 min, then transfer the mold to another flat vulcanizer for cold pressing for 5 - 10 min. Take out the mold, and then through demolding, laying flat and cooling, and removing flash, the special cable material is obtained.

7. The application of the special cable material for low-smoke and halogen-free new energy wire and cable according to any one of claims 1 to 5, characterized in that, The special cable material is used for preparing wires and cables for new energy electric vehicles, wires and cables for charging piles, outdoor power transmission cables, and wires and cables for electrical equipment.

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