阅读说明：本技术 一种高负荷阻燃钢丝绳及其制备方法 (High-load flame-retardant steel wire rope and preparation method thereof ) 是由 林柱英 吴海峰 王勇军 于 2021-08-31 设计创作，主要内容包括：本发明提供一种高负荷阻燃钢丝绳,包括一复合绳芯与绳股,其特征在于,所述复合绳芯包括七组组合丝,其中六组所述组合丝螺旋包捻住另一组所述组合丝,所述组合丝包括一超高分子量聚乙烯纤维丝和若干芳纶纤维丝,所述芳纶纤维丝螺旋包捻住所述超高分子量聚乙烯纤维丝,所述绳股包括一次外层股和一外层股,所述次外层股包捻住所述混合绳芯,所述外层股包捻住所述次外层股,所述外层股外设置一层阻燃层,所述阻燃层的原料及其质量分数为：三元乙丙橡胶50％～60％,丙烯腈接枝三元乙丙橡胶5％～10％,氯丁橡胶10％～17％,硬脂酸1％～2％,促进剂1％～2％,硫化剂2％～3％,防老剂1％～2％,阻燃润滑剂3％～5％以及阻燃剂8％～13％。所述钢丝绳具有高负荷能力,耐热稳定性好以及阻燃性能强,适用于高温易燃场合。(The invention provides a high-load flame-retardant steel wire rope which comprises a composite rope core and rope strands and is characterized in that the composite rope core comprises seven groups of combined yarns, wherein six groups of combined yarns spirally wrap and twist another group of combined yarns, the combined yarns comprise an ultrahigh molecular weight polyethylene fiber yarn and a plurality of aramid fiber yarns, the aramid fiber yarns spirally wrap and twist the ultrahigh molecular weight polyethylene fiber yarns, the rope strands comprise a primary outer layer strand and a secondary outer layer strand, the secondary outer layer strand wraps and twists the mixed rope core, the secondary outer layer strand wraps and twists the secondary outer layer strand, a flame-retardant layer is arranged outside the outer layer strand, and the flame-retardant layer comprises the following raw materials in parts by mass: 50-60% of ethylene propylene diene monomer, 5-10% of acrylonitrile grafted ethylene propylene diene monomer, 10-17% of chloroprene rubber, 1-2% of stearic acid, 1-2% of accelerator, 2-3% of vulcanizing agent, 1-2% of anti-aging agent, 3-5% of flame retardant lubricant and 8-13% of flame retardant. The steel wire rope has high load capacity, good heat-resistant stability and strong flame retardant property, and is suitable for high-temperature inflammable occasions.)

1. The high-load flame-retardant steel wire rope comprises a composite rope core and rope strands, and is characterized in that the composite rope core comprises seven groups of combined yarns, wherein six groups of combined yarns spirally wrap another group of combined yarns, the combined yarns comprise an ultrahigh molecular weight polyethylene fiber yarn and a plurality of aramid fiber yarns, the aramid fiber yarns spirally wrap the ultrahigh molecular weight polyethylene fiber yarns, the rope strands comprise an outer layer strand and an outer layer strand, the mixed rope core is wrapped and twisted by the outer layer strand, the outer layer strand wraps the outer layer strand, a flame-retardant layer is arranged outside the outer layer strand, and the flame-retardant layer is prepared from the following raw materials in percentage by mass:

50-60% of ethylene propylene diene monomer, 5-10% of acrylonitrile grafted ethylene propylene diene monomer, 10-17% of chloroprene rubber, 1-2% of stearic acid, 1-2% of accelerator, 2-3% of vulcanizing agent, 1-2% of anti-aging agent, 3-5% of flame retardant lubricant and 8-13% of flame retardant.

2. A high load flame retardant steel cord according to claim 1, characterized in that: the mixed rope core and set up a nylon fiber layer between the secondary outer layer thigh, the nylon fiber layer adds and has brominated styrene polymer.

3. A high load flame retardant steel cord according to claim 1, characterized in that: the composite rope core comprises a composite rope core and outer layer strands, wherein the outer layer strands wrap and twist the composite rope core in a left-hand cross twisting mode, the outer layer strands wrap and twist the outer layer strands in a right-hand cross twisting mode, the outer layer strands and the outer layer strands both adopt phosphated coating steel wires, the structure of the outer layer strands is 1 x 3, and the structure of the outer layer strands is 1 x 7.

4. A high load flame retardant steel cord according to claim 1, characterized in that: and a wear-resistant synthetic resin layer is arranged outside the flame-retardant layer.

5. A high load flame retardant steel cord according to claim 1, characterized in that: the accelerator is one or more of di-n-butyl zinc disulfide carbamate, ethylene thiourea and tetramethyl thiuram disulfide.

6. A high load flame retardant steel cord according to claim 1, characterized in that: the vulcanizing agent is sulfur.

7. A high load flame retardant steel cord according to claim 1, characterized in that: the flame retardant is two or more of melamine cyanurate, triaryl phosphate FR-506 and micron aluminum hydroxide.

8. A high load flame retardant steel cord according to claim 1, characterized in that: the flame-retardant lubricant is MB-202, one of cyanuric acid melamine complex salt.

9. A method for preparing a high-load flame-retardant steel wire rope for producing the high-load flame-retardant steel wire rope according to any one of claims 1 to 8, comprising the steps of:

step 1, preparing fiber yarns: spinning aramid fibers into aramid fiber yarns through a machine, spinning the aramid fiber yarns into aramid fiber yarns, spinning ultrahigh molecular weight polyethylene fibers into ultrahigh molecular weight polyethylene fiber yarns through the machine, and spinning the ultrahigh molecular weight polyethylene fiber yarns into ultrahigh molecular weight polyethylene fiber yarns;

step 2, preparing a rope core: spirally wrapping and twisting a plurality of aramid fiber yarns with an ultra-high molecular weight polyethylene fiber yarn to obtain a group of combined yarns, preparing the other six groups of combined yarns in the same way, taking one group of combined yarns as a center, wrapping and twisting the other six groups of combined yarns around the center combined yarn in a spiral way to obtain the mixed rope core, and spraying grease while twisting in the wrapping and twisting process;

step 3, preparing a nylon fiber layer: melting and uniformly mixing a brominated styrene polymer and nylon, spinning the mixture into nylon fiber yarns by using a machine, and tightly wrapping a plurality of nylon fiber yarns outside the mixed rope core by using the machine and compacting the nylon fiber yarns;

step 4, preparing: 3 steel wires are taken and twisted into a strand A in a 1 x 3 mode, and 7 steel wires are taken and twisted into a strand B in a 1 x 7 mode;

step 5, rope combination: wrapping and twisting the strand A with the composite rope core in a right-hand twisting mode by using a machine to form a secondary outer-layer strand, wrapping and twisting the strand B with the secondary outer-layer strand in a left-hand twisting mode to obtain an outer-layer strand, compacting with the machine after twisting, brushing a flame-retardant layer on the outer-layer strand in a machine brushing mode, cooling the flame-retardant layer at room temperature, and coating a layer of wear-resistant synthetic resin on the surface in a soaking and drawing mode to obtain the steel wire rope; the preparation method of the flame-retardant layer comprises the following steps of;

the preparation method of the flame-retardant layer comprises the following steps:

(1) weighing the raw materials according to the mass parts for later use;

(2) adding ethylene propylene diene monomer and acrylonitrile grafted ethylene propylene diene monomer into an internal mixer, setting the temperature to be 90-100 ℃, plasticating for 5min, adding stearic acid, and continuously banburying for 10min to obtain first mixed rubber;

(3) adding chloroprene rubber into the first mixed rubber, carrying out banburying for 10min, adding an accelerator and a vulcanizing agent, carrying out banburying for 5min at the temperature of 110-120 ℃, adding a flame-retardant lubricant and a flame retardant, carrying out banburying for 15min, then discharging rubber, cooling, standing for 12h, putting into the banbury mixer again, adding an anti-aging agent, carrying out banburying for 10min at 80 ℃, and then discharging rubber.

10. The method for preparing a high load flame retardant steel cord according to claim 9, wherein the following step 3.1 is further included between step 3 and step 4:

step 3.1: and (3) carrying out phosphating treatment on a plurality of steel wires with two diameters to obtain a phosphating coating steel wire, wherein the diameter of the outer layer strand steel wire is 2-3 times that of the secondary outer layer strand steel wire.

Technical Field

The invention relates to the technical field of steel wire ropes, in particular to a high-load flame-retardant steel wire rope.

Background

The steel wire rope is a spiral steel wire bundle formed by twisting steel wires with mechanical property and geometric dimension meeting requirements together according to a certain rule, and consists of the steel wires, a rope core and lubricating grease. The steel wire rope has the advantages of high strength, light dead weight, stable work, difficulty in breaking the whole wire rope, reliable work and wide application in daily life. Due to the unique properties of steel wire ropes, steel wire ropes have been essential materials or parts in the fields of metallurgy, mining, oil and gas drilling, machinery, chemical engineering, aerospace and the like, and therefore, the quality of steel wire ropes is also concerned by a plurality of industries.

At present, with the more diversified use of the steel wire rope, the requirements on the characteristics of the steel wire rope in all aspects are higher and higher. For some specific working occasions, the used steel wire ropes also have different requirements, such as the steel wire ropes used by certain fire-fighting facilities and the steel wire ropes used in high-temperature flammable and explosive environments such as metallurgical mining and the like, and certain flame retardant property is required. Because the lubricating grease in the steel wire rope is inflammable, the lubricating grease can be rapidly burnt when contacting open fire, the metallographic structure of the steel wire is subjected to phase change at high temperature, and the tensile strength and the toughness are sharply reduced. In particular, when the core of the steel cord is made of natural fibers or synthetic fibers, the possibility of the steel cord burning in a high-temperature flammable environment is further increased. The steel wire rope core is one of the important composition structures of the steel wire rope, can play a supporting role and reduce the pressure effect between strands, keeps the stable physical structure of the steel wire rope, and usually stores a large amount of lubricating grease so as to achieve the internal lubricating effect of the steel wire rope. Therefore, the whole structure of the steel wire rope can be changed due to the burning of the rope core inside the steel wire rope, and if the steel wire rope is just in a working state at the moment, the severe condition of sudden fracture is easy to occur, and even more serious safety accidents occur. Therefore, aiming at some high-temperature inflammable occasions, the steel wire rope with high load and good flame retardant property is very necessary, so that the working efficiency can be improved, and the construction safety can be improved.

Disclosure of Invention

The invention aims to provide a high-load flame-retardant steel wire rope and a preparation method thereof, which can improve the working efficiency and reduce the risk of safety accidents caused by internal combustion of the steel wire rope under the high-temperature inflammable working condition.

The high-load flame-retardant steel wire rope comprises a composite rope core and rope strands, and is characterized in that the composite rope core comprises seven groups of combined yarns, wherein six groups of combined yarns spirally wrap another group of combined yarns, the combined yarns comprise an ultrahigh molecular weight polyethylene fiber yarn and a plurality of aramid fiber yarns, the aramid fiber yarns spirally wrap the ultrahigh molecular weight polyethylene fiber yarns, the rope strands comprise an outer layer strand and an outer layer strand, the mixed rope core is wrapped and twisted by the outer layer strand, the outer layer strand wraps the outer layer strand, a flame-retardant layer is arranged outside the outer layer strand, and the flame-retardant layer is prepared from the following raw materials in percentage by mass: 50-60% of ethylene propylene diene monomer, 5-10% of acrylonitrile grafted ethylene propylene diene monomer, 10-17% of chloroprene rubber, 1-2% of stearic acid, 1-2% of accelerator, 2-3% of vulcanizing agent, 1-2% of anti-aging agent, 3-5% of flame retardant lubricant and 8-13% of flame retardant.

Further preferably, the flame-retardant layer comprises the following raw materials in percentage by mass: 51% of ethylene propylene diene monomer, 10% of acrylonitrile grafted ethylene propylene diene monomer, 17% of chloroprene rubber, 2% of stearic acid, 2% of accelerator, 3% of vulcanizing agent, 2% of anti-aging agent, 3% of flame retardant lubricant and 10% of flame retardant.

Preferably, a nylon fiber layer is arranged between the mixed rope core and the secondary outer layer strand, and brominated styrene polymer is added in the nylon fiber layer.

Preferably, the secondary outer layer strands wrap and twist the composite rope core in a left-hand cross twisting mode, the outer layer strands wrap and twist the secondary outer layer strands in a right-hand cross twisting mode, the outer layer strands and the secondary outer layer strands both adopt phosphated coating steel wires, the structure of the secondary outer layer strands is 1 x 3, and the structure of the outer layer strands is 1 x 7.

Preferably, a wear-resistant synthetic resin layer is disposed outside the flame retardant layer.

Preferably, the accelerator is one or more of zinc di-n-butyl disulfide carbamate, ethylene thiourea and tetramethyl thiuram disulfide. More preferably, the accelerator is a combination of ethylene thiourea and tetramethylthiuram disulfide.

Preferably, the vulcanizing agent is sulfur.

Preferably, the flame retardant is two or more of melamine cyanurate, triaryl phosphate FR-506, and micron aluminum hydroxide. Further preferably, the flame retardant is a combination of melamine cyanurate and micron aluminum hydroxide.

Preferably, the flame-retardant lubricant is MB-202, one of melamine cyanurate complex salts.

A preparation method of a high-load flame-retardant steel wire rope is characterized by comprising the following steps:

step 1, preparing fiber yarns: spinning aramid fibers into aramid fiber yarns through a machine, spinning the aramid fiber yarns into aramid fiber yarns, spinning ultrahigh molecular weight polyethylene fibers into ultrahigh molecular weight polyethylene fiber yarns through the machine, and spinning the ultrahigh molecular weight polyethylene fiber yarns into ultrahigh molecular weight polyethylene fiber yarns;

step 2, preparing a rope core: spirally wrapping and twisting a plurality of aramid fiber yarns with an ultra-high molecular weight polyethylene fiber yarn to obtain a group of combined yarns, preparing the other six groups of combined yarns in the same way, taking one group of combined yarns as a center, wrapping and twisting the other six groups of combined yarns around the center combined yarn in a spiral way to obtain the mixed rope core, and spraying grease while twisting in the wrapping and twisting process;

step 3, preparing a nylon fiber layer: melting and uniformly mixing a brominated styrene polymer and nylon, spinning the mixture into nylon fiber yarns by using a machine, and tightly wrapping a plurality of nylon fiber yarns outside the mixed rope core by using the machine and compacting the nylon fiber yarns;

step 4, preparing: 3 steel wires are taken and twisted into a strand A in a 1 x 3 mode, and 7 steel wires are taken and twisted into a strand B in a 1 x 7 mode;

step 5, rope combination: wrapping and twisting the strand A with the composite rope core in a right-hand twisting mode by using a machine to form a secondary outer-layer strand, wrapping and twisting the strand B with the secondary outer-layer strand in a left-hand twisting mode to obtain an outer-layer strand, compacting with the machine after twisting, brushing a flame-retardant layer on the outer-layer strand in a machine brushing mode, cooling the flame-retardant layer at room temperature, and coating a layer of wear-resistant synthetic resin on the surface in a soaking and drawing mode to obtain the steel wire rope; the preparation method of the flame-retardant layer comprises the following steps of;

the preparation method of the flame-retardant layer comprises the following steps:

(1) weighing the raw materials according to the mass parts for later use;

(2) adding ethylene propylene diene monomer and acrylonitrile grafted ethylene propylene diene monomer into an internal mixer, setting the temperature to be 90-100 ℃, plasticating for 5min, adding stearic acid, and continuously banburying for 10min to obtain first mixed rubber;

(3) adding chloroprene rubber into the first mixed rubber, carrying out banburying for 10min, adding an accelerator and a vulcanizing agent, carrying out banburying for 5min at the temperature of 110-120 ℃, adding a flame-retardant lubricant and a flame retardant, carrying out banburying for 15min, then discharging rubber, cooling, standing for 12h, putting into the banbury mixer again, adding an anti-aging agent, carrying out banburying for 10min at 80 ℃, and then discharging rubber.

Preferably, the following step 3.1 is further included between step 3 and step 4:

step 3.1: and (3) carrying out phosphating treatment on a plurality of steel wires with two diameters to obtain a phosphating coating steel wire, wherein the diameter of the outer layer strand steel wire is 2-3 times that of the secondary outer layer strand steel wire.

The invention has the following beneficial effects: according to the invention, the aramid fiber and the ultra-high molecular weight polyethylene fiber are combined to prepare the composite rope core of the steel wire rope by using the specific structure, and the high molecular material rope core can further improve the load capacity of the steel wire rope and has good tensile capacity and toughness. The flame-retardant layer is arranged outside the rope strand of the steel wire rope, so that the internal structure of the steel wire rope can be protected, and the phenomenon that the internal structure of the steel wire rope is broken due to the change of the internal structure of the steel wire rope due to the open fire combustion under the high-temperature inflammable condition is avoided.

The ultra-high molecular weight polyethylene fiber has ultra-strong wear resistance, self-lubrication, high strength and high modulus, and the fiber is used as the main raw material of the rope core of the steel wire rope, so that the load bearing capacity of the steel wire rope can be greatly enhanced, and the steel wire rope has good deflection life. But the ultra-high molecular weight polyethylene fiber has weak temperature resistance, and the aramid fiber has high strength and modulus, light weight, excellent temperature resistance effect, lasting thermal stability and outstanding flame retardance. Therefore, the aramid fiber yarn is added in the rope core structure to serve as the outer layer of the combined yarn, so that the high strength of the rope core is guaranteed, the heat resistance of the rope core is enhanced, and the defect that the conventional rope core is flammable is overcome.

In order to further improve the flame retardant property of the steel wire rope, a flame retardant layer which takes rubber as a main raw material is arranged outside the strand. The ethylene propylene diene monomer main chain is composed of chemically stable saturated hydrocarbon, and only contains unsaturated double bonds in the side chain, so that the ethylene propylene diene monomer is strong in ozone resistance, heat resistance and aging resistance. The ethylene propylene diene monomer rubber also has low density and high filling property, can absorb a large amount of filler and has little influence on the characteristics, so the rubber is used as a main body, has low cost and strong practicability. However, the ethylene propylene diene monomer has poor self-adhesion, mutual adhesion and flame retardant property, and the chloroprene rubber can make up for the defect because the chloroprene rubber has the characteristics of acid and alkali resistance, oil resistance, heat resistance, flame retardancy, high adhesion strength and room-temperature curing. The acrylonitrile grafted ethylene propylene diene monomer rubber is used as a compatilizer of ethylene propylene diene monomer rubber and chloroprene rubber, and can improve the compatibility of the ethylene propylene diene monomer rubber and the chloroprene rubber. The flame retardant and the flame-retardant lubricant are added, so that the high-temperature stability of the rubber mixture is improved, and good lubricating and flame-retardant effects are achieved.

Drawings

FIG. 1 is a schematic structural view of a high-load flame-retardant steel wire rope according to the present invention

In the figure: 1-a steel wire rope body; 2-composite rope core; 3-a nylon fiber layer; 4-minor outer ply; 5-outer layer strand; 6-a flame retardant layer; 7-a wear-resistant synthetic resin layer; 201-ultra high molecular weight polyethylene fiber filaments; 202-aramid fiber yarn.

Detailed Description

The embodiments described below are only a part of the embodiments of the present invention, and not all of them. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1, the embodiment provides a high-load flame-retardant steel wire rope, which includes a composite rope core 2 and a strand, where the composite rope core 2 includes seven groups of combined filaments, where six groups of combined filaments spirally wrap and twist another group of combined filaments, the combined filaments include an ultra-high molecular weight polyethylene fiber filament 201 and a plurality of aramid fiber filaments 202, the aramid fiber filaments 202 spirally wrap and twist the ultra-high molecular weight polyethylene fiber filament 201, the strand includes a primary outer layer strand 4 and an outer layer strand 5, the secondary outer layer strand 4 wraps and twists the mixed rope core 2, the outer layer strand 5 wraps and twists the secondary outer layer strand 4, a flame-retardant layer 6 is disposed outside the outer layer strand 5, and the flame-retardant layer 6 is made of raw materials in the following mass fractions:

50-60% of ethylene propylene diene monomer, 5-10% of acrylonitrile grafted ethylene propylene diene monomer, 10-17% of chloroprene rubber, 1-2% of stearic acid, 1-2% of accelerator, 2-3% of vulcanizing agent, 1-2% of anti-aging agent, 3-5% of flame retardant lubricant and 8-13% of flame retardant.

Further preferably, the flame-retardant layer comprises the following raw materials in percentage by mass: 51% of ethylene propylene diene monomer, 10% of acrylonitrile grafted ethylene propylene diene monomer, 17% of chloroprene rubber, 2% of stearic acid, 2% of accelerator, 3% of vulcanizing agent, 2% of anti-aging agent, 3% of flame retardant lubricant and 10% of flame retardant.

Preferably, a nylon fiber layer 3 is arranged between the mixed rope core 2 and the secondary outer layer strand 4, and brominated styrene polymer is added in the nylon fiber layer. The nylon fiber layer can play a stabilizing role in the composite rope core structure, and the oil storage effect of the rope core is improved. However, the oxygen index of the nylon is low, the nylon is easy to burn, the brominated styrene polymer has good thermal stability, and the flame retardant property of the nylon can be improved after the brominated styrene polymer is melt blended with the nylon.

Preferably, the secondary outer layer strands 4 wrap and twist the composite rope core 2 in a left-hand cross twisting mode, the outer layer strands 5 wrap and twist the secondary outer layer strands 4 in a right-hand cross twisting mode, the outer layer strands 5 and the secondary outer layer strands 4 both adopt phosphated coated steel wires, the structure of the secondary outer layer strands is 1 x 3, and the structure of the outer layer strands is 1 x 7.

Preferably, a wear-resistant synthetic resin layer 7 is disposed outside the flame retardant layer 6. The outermost layer of the steel wire rope is provided with the wear-resistant synthetic resin layer, so that the wear-resistant effect of the steel wire rope to the outside can be improved, and certain benefits are achieved in the aspect of compression resistance.

Preferably, the accelerator is one or more of zinc di-n-butyl disulfide carbamate, ethylene thiourea and tetramethyl thiuram disulfide.

Preferably, the vulcanizing agent is sulfur.

Preferably, the flame retardant is two or more of melamine cyanurate, triaryl phosphate FR-506, and micron aluminum hydroxide. Further preferably, the flame retardant is a combination of melamine cyanurate and micron aluminum hydroxide. Aluminum hydroxide is a filler type flame retardant, can be decomposed by heating, absorbs a large amount of heat in the decomposition process, and can reduce the temperature of a combustion part to prevent the combustion part from continuing to burn. In addition, the water formed by the thermal decomposition of aluminum hydroxide exists in the form of water vapor, and can dilute the surrounding oxygen concentration to inhibit combustion. The melamine cyanurate is a nitrogen-containing halogen-free environment-friendly flame retardant, has excellent mechanical property and electrical property, no discoloration, low smoke, low corrosivity and good thermal stability.

Preferably, the flame-retardant lubricant is MB-202, one of melamine cyanurate complex salts. The proper amount of lubricant is added, so that the internal friction between the strand and the flame-retardant layer can be reduced, the flame-retardant coating has good matching performance with the flame retardant, and the flame-retardant effect is further improved.

Example 2

The embodiment provides a preparation method of a high-load flame-retardant steel wire rope, which comprises the following steps:

step 1, preparing fiber yarns: spinning aramid fibers into aramid fiber yarns through a machine, spinning the aramid fiber yarns into aramid fiber yarns 202, spinning ultrahigh molecular weight polyethylene fibers into ultrahigh molecular weight polyethylene fiber yarns through the machine, and spinning the ultrahigh molecular weight polyethylene fiber yarns into ultrahigh molecular weight polyethylene fiber yarns 201;

step 2, preparing a rope core: spirally wrapping and twisting a plurality of aramid fiber filaments 202 around an ultra-high molecular weight polyethylene fiber 201 to obtain a group of combined filaments, preparing the other six groups of combined filaments in the same way, taking one group of combined filaments as a center, wrapping and twisting the other six groups of combined filaments around the center combined filament in a spiral way to obtain the mixed rope core 2, and pouring grease while twisting in the wrapping and twisting process;

step 3, preparing a nylon fiber layer: melting and uniformly mixing a brominated styrene polymer and nylon, spinning the mixture into nylon fiber yarns by using a machine, and tightly wrapping a plurality of nylon fiber yarns outside the mixed rope core by using the machine and compacting the nylon fiber yarns;

step 4, preparing: 3 steel wires are taken and twisted into a strand A in a 1 x 3 mode, and 7 steel wires are taken and twisted into a strand B in a 1 x 7 mode;

step 5, rope combination: wrapping and twisting the strand A with the composite rope core in a right-hand twisting mode by using a machine to form a secondary outer-layer strand 4, wrapping and twisting the strand B with the secondary outer-layer strand in a left-hand twisting mode to obtain an outer-layer strand 5, compacting by using the machine after twisting, brushing a flame-retardant layer 6 on the outer-layer strand in a machine brushing mode, cooling the flame-retardant layer at room temperature, and coating a layer of wear-resistant synthetic resin 7 on the surface in a soaking and drawing mode to obtain the steel wire rope; the preparation method of the flame-retardant layer comprises the following steps:

(1) weighing the raw materials according to the mass parts for later use;

(2) adding ethylene propylene diene monomer and acrylonitrile grafted ethylene propylene diene monomer into an internal mixer, setting the temperature to be 90-100 ℃, plasticating for 5min, adding stearic acid, and continuously banburying for 10min to obtain first mixed rubber;

(3) adding chloroprene rubber into the first mixed rubber, carrying out banburying for 10min, adding an accelerator and a vulcanizing agent, carrying out banburying for 5min at the temperature of 110-120 ℃, adding a flame-retardant lubricant and a flame retardant, carrying out banburying for 15min, then discharging rubber, cooling, standing for 12h, putting into the banbury mixer again, adding an anti-aging agent, carrying out banburying for 10min at 80 ℃, and then discharging rubber.

Preferably, the following step 3.1 is further included between step 3 and step 4:

step 3.1: and (3) carrying out phosphating treatment on a plurality of steel wires with two diameters to obtain a phosphating coating steel wire, wherein the diameter of the outer layer strand steel wire is 2-3 times that of the secondary outer layer strand steel wire. The outer strand adopts the steel wire of major diameter, can improve wire rope to outside resistance to compression shock resistance, can also effectively promote wire rope's load bearing.

Example 3

This example tests the performance of steel cords with different flame retardant layer compositions.

In the embodiment, a high-load flame-retardant steel wire rope with the diameter of 20mm is used for testing, wherein the preparation method of the steel wire rope is the same as that of the steel wire rope in the embodiment 2, and the difference is that the raw material ratio of the flame-retardant layer is changed in the step 5.

Table 1 is a table of different component compositions of a flame retardant layer of a high load flame retardant steel wire rope:

	example 1	Example 2	Example 3	Example 4	Example 5
						Ethylene propylene diene monomer%	51	52	55	58	60
Acrylonitrile graft ethylene propylene diene monomer%	10	10	8	7	6
						Chloroprene rubber%	17	15	13	15	11
Stearic acid%	2	2	2	2	2
						Ethylene thiourea%	1	1	1	1	1
Tetramethyl thiuram disulfide%	1	1	1	1	1
						Sulfur content%	3	3	3	3	3
Anti-aging agent%	2	1	1	1	1
						MB-202％	3	3	3	3	3
Melamine cyanurate%	5	6	8	7	7
						Micron aluminum hydroxide%	5	6	5	2	5

Comparative example 1

Table 2 is a table of the components of comparative example 1 of the flame retardant layer of a high load flame retardant steel wire rope:

	example 1
		Ethylene propylene diene monomer%	70
Stearic acid%	6
		Tetramethyl thiuram disulfide%	3
Sulfur content%	4
		Anti-aging agent%	2
MB-202％	3
		Melamine cyanurate%	7
Micron aluminum hydroxide%	5

After the steel wire ropes of the different flame retardant layer components of the above examples 1 to 5 and the comparative example 1 were prepared according to the preparation method of the above example 2, 10 samples of each component of the steel wire rope without any damage to the surface were respectively subjected to a tensile test and an alcohol burner combustion test, the breaking tensile test results were averaged, the combustion results were respectively averaged and maximized, and the test results were as follows:

	example 1	Example 2	Example 3	Example 4	Example 5	Example 1
							Breaking tension/KN of steel wire rope	311	309	308	311	310	302
Mean flame combustion/s	1.4	1.6	1.7	1.5	1.8	2.3
							Maximum flame combustion/s	1.9	2.1	2.2	2.0	2.4	2.5
Mean flameless combustion/s	2.0	2.1	2.1	2.0	2.5	3.3
							Maximum value of flameless combustion/s	2.8	2.9	3.0	2.9	3.1	3.6
Flame retardant rating	V0	V0	V0	V0	V0	V1

The test result can be obtained, the steel wire rope has high-strength breaking force, high-load work can be carried out, the flame-retardant layer is arranged outside the steel wire rope, the burning time of the steel wire rope can be shortened, the steel wire rope has a good flame-retardant effect, and the rope core inside the steel wire rope can be prevented from burning and breaking. The flame retardant effect of the ethylene propylene diene monomer is not ideal, the chloroprene rubber is added to just make up the defect, the chloroprene rubber and the ethylene propylene diene monomer are mixed and vulcanized according to a certain proportion, the acrylonitrile grafted ethylene propylene diene monomer is added to promote the mutual compatibility effect, the addition of a flame retardant can be correspondingly reduced, and the flame retardant rubber with good flame retardant effect can be obtained. The melamine cyanurate and the aluminum hydroxide are combined for use, so that the flame retardant effect is further improved.

The present invention has been described in detail with reference to the embodiments, and it should be noted that the specific features described in the above embodiments may be combined and changed in any suitable manner without departing from the scope of the present invention, and various possible combinations are not separately described. In addition, other modifications and combinations of the various features of the invention should also be considered as disclosed in the present application, and all fall within the scope of the invention.