Steel wire rope core flame-retardant conveying belt and preparation process thereof

Abstract

The invention relates to the technical field of conveying belts, in particular to a steel wire rope core flame-retardant conveying belt and a preparation process thereof. The preparation method comprises the following steps: mixing a sulfydryl-terminated flame-retardant material with natural rubber and butadiene rubber in advance, and carrying out a stirring reaction to obtain the reinforced flame-retardant rubber material. Mixing the reinforced flame-retardant rubber material, a flame retardant, a vulcanizing agent, an accelerant, a reinforcing agent and an anti-aging agent, plastifying, mixing and calendering to obtain a rubber sheet; the film comprises an upper film, a lower film and a middle film. The steel wire rope core serves as the center, then the middle rubber sheet wraps the periphery of the steel wire rope core, the glass fiber cloth is attached to the upper side and the lower side of the middle rubber sheet respectively, the upper rubber sheet and the lower rubber sheet are arranged on the outermost side respectively, and then a finished product is obtained through cold pressing and vulcanization. The finished product prepared by the invention has good flame retardant property, so that the finished product has a wide application prospect in the technical field of conveyor belts.

Description

Technical Field

[0001] The invention relates to the technical field of conveyor belts, in particular to a steel cord flame-retardant conveyor belt and a preparation process thereof. Background Art

[0002] In modern industrial transportation, steel cord conveyor belts, with their exceptional performance, play a vital role, demonstrating irreplaceable modern value. Economically, steel cord conveyor belts, with their high strength and long life, significantly reduce transportation costs for businesses. They can withstand heavy material loads, reducing the expense and time associated with frequent belt replacements. Furthermore, their efficient transport capacity improves production efficiency, enabling businesses to complete more transport tasks per unit time and increasing economic benefits. In industries like coal and mining, where large quantities of materials require long-distance, high-load transport, the use of steel cord conveyor belts makes transportation more efficient and stable, reducing operating costs and enhancing businesses' market competitiveness. Regarding safety, steel cord conveyor belts offer excellent flame retardancy and tear resistance, providing reliable safety for industrial production. However, many locations where steel cord conveyor belts are used present fire hazards. For example, underground coal mines are filled with flammable and explosive gas and coal dust. If a conveyor belt ignites due to friction, overheating, or other factors, it is highly likely to cause a gas explosion and widespread fire, resulting in significant casualties and property damage. At the same time, ordinary conveyor belts will release a large amount of toxic and harmful gases and smoke when burning, causing serious pollution to the environment.

[0003] In order to overcome the defects of the prior art, the present invention provides a steel cord flame retardant conveyor belt and a preparation process thereof. Summary of the Invention

[0004] The object of the present invention is to provide a steel cord flame retardant conveyor belt and a preparation process thereof, so as to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A preparation process of a steel cord flame-retardant conveyor belt comprises the following steps:

[0007] Step 1: pre-mix the mercapto-terminated flame retardant material with natural rubber and butadiene rubber, and stir and react at 70-75° C. for 1-2 hours to obtain a reinforced flame retardant rubber material;

[0008] Step 2: Mixing the flame retardant reinforced rubber material, flame retardant, vulcanizing agent, accelerator, reinforcing agent and antioxidant, and performing plasticizing, mixing and calendering to obtain a film; the film includes an upper film, a lower film and an intermediate film;

[0009] Step 3: Take the steel wire rope core as the center, and then wrap the middle film around the steel wire rope core. The upper and lower sides of the middle film are respectively attached to the glass fiber cloth, and the upper and lower films are respectively set on the outermost sides. Then, it is cold pressed and vulcanized to obtain the finished product.

[0010] More optimally, in step one, the contents of the components of the reinforced flame retardant rubber material are: by mass, 60-80 parts of natural rubber, 40-50 parts of butadiene rubber, and 10-15 parts of mercapto-terminated flame retardant material.

[0011] More optimally, the preparation process of the mercapto-terminated flame retardant material is:

[0012] S1: Under a nitrogen atmosphere, eugenol is dissolved in tetrahydrofuran, triethylamine is added, and the mixture is stirred thoroughly to obtain a eugenol solution; hexachlorocyclotriphosphazene is dissolved in tetrahydrofuran to obtain a hexachlorocyclotriphosphazene solution; the eugenol solution is allowed to stand at 0-3°C for 5-8 minutes, and the hexachlorocyclotriphosphazene solution is added dropwise. After the addition is completed, stirring is continued at 25-30°C for 2.5-3.5 hours, and the mixture is refluxed at 60-65°C for 6-8 hours. After the reaction is completed, the mixture is filtered, rotary evaporated, dissolved, washed, dried, and filtered to obtain an intermediate product;

[0013] S2: Under a nitrogen environment, dissolve 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) in ethyl acetate to obtain reaction solution 1; dissolve the intermediate product and azobisisobutyronitrile in ethyl acetate to obtain reaction solution 2; add reaction solution 2 dropwise to reaction solution 1, and react at 70-75°C for 25-30 hours after the addition is completed to obtain a thiol-terminated flame retardant material.

[0014] More optimally, when preparing the intermediate product, the reaction molar ratio of eugenol, triethylamine, and hexachlorocyclotriphosphazene is (6.5-7.0):4:1; when preparing the thiol-terminated flame retardant material, the reaction molar ratio of 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) and the intermediate product is (6.3-6.5):1.

[0015] More optimally, in step 2, the contents of the components of the film are: by mass, 110-145 parts of reinforced flame retardant rubber material, 20-25 parts of flame retardant, 3-4 parts of vulcanizing agent, 1-2 parts of accelerator, 40-60 parts of reinforcing agent, and 4-6 parts of antioxidant; the vulcanizing agent is sulfur; the accelerator is zinc dibutyldithiocarbamate; the reinforcing agent is carbon black; and the antioxidant is N-phenyl-β-naphthylamine.

[0016] More optimally, the preparation process of the flame retardant is:

[0017] S1: Under a nitrogen atmosphere, eugenol is dissolved in tetrahydrofuran, and triethylamine is added and stirred thoroughly to obtain a eugenol solution; octachloropropylsilsesquioxane is dissolved in tetrahydrofuran to obtain a siloxane solution; the eugenol solution is allowed to stand at 0-3°C for 5-8 minutes, and the siloxane solution is added dropwise. After the addition is completed, stirring is continued at 25-30°C for 2.5-3.5 hours, and reflux reaction is carried out at 65-70°C for 6-8 hours. After the reaction is completed, the modified siloxane is obtained by filtering, rotary evaporation, dissolving, washing, drying, and filtering.

[0018] S2: Under a nitrogen environment, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid are mixed and stirred at 130-140° C. for 25-30 hours. After the reaction, the mixture is precipitated, filtered, washed and vacuum dried to obtain a bisaminophosphaphenanthrene material;

[0019] S3: Add modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane and melamine to N,N-dimethylformamide, heat and dissolve at 80-90°C for 20-30 minutes to obtain a mixed solution, and then react the mixed solution at a constant temperature of 95-105°C for 25-30 hours. After the reaction is completed, cool, filter, wash and vacuum dry to obtain a flame retardant.

[0020] More optimally, when preparing modified silicone, the reaction mass ratio of eugenol, triethylamine, and octachloropropylsilsesquioxane is 9:6:(13-15); when preparing bisaminophosphaphenanthrene materials, the reaction mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline, and p-toluenesulfonic acid is (10-12):6:17:0.3; when preparing flame retardants, the reaction mass ratio of modified silicone, bisaminophosphaphenanthrene materials, 4,4'-diaminodiphenylmethane, and melamine is 14.4:(2.5-2.7):1:(1.3-1.5).

[0021] More optimally, in step three, the cold pressing parameters are: pressure 2.0-2.5 MPa, time 15-20 min, temperature 25-30°C; and the vulcanization parameters are: temperature 140-160°C, time 30-50 min.

[0022] Beneficial effects of the present invention:

[0023] The present invention is characterized in that, in step one, a thiol-terminated flame retardant material is obtained by adding eugenol, hexachlorocyclotriphosphazene, 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) and azobisisobutyronitrile. The thiol-terminated flame retardant material is mixed with natural rubber and butadiene rubber in advance, and stirred to react to obtain a reinforced flame retardant rubber material. In this step, eugenol and hexachlorocyclotriphosphazene undergo a substitution reaction to obtain an intermediate product; then, the intermediate product with a double bond introduced and 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) undergo a thiol-ene click reaction to obtain a thiol-terminated flame retardant material. Then, the thiol-terminated flame retardant material is mixed with natural rubber and butadiene rubber in advance, and a thiol-ene click reaction occurs to obtain a reinforced flame retardant rubber material with good flame retardant properties and uniform dispersion of raw materials.

[0024] The present invention is characterized in that, in step 2, a flame retardant is obtained by adding eugenol, octachloropropylsilsesquioxane, bisaminophosphaphenanthrene, 4,4'-diaminodiphenylmethane, and melamine. The reinforced flame-retardant rubber material, flame retardant, vulcanizing agent, accelerator, reinforcing agent, and antioxidant are mixed and subjected to plasticating, mixing, and calendering to obtain a film. In this step, eugenol and octachloropropylsilsesquioxane undergo a substitution reaction to obtain a modified siloxane. In this step, the chlorine groups in the octachloropropylsilsesquioxane are adjusted by mass ratio to ensure that there are residual chlorine groups, that is, a certain amount of chlorine groups remain on the surface of the modified siloxane. Then, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid are mixed and reacted to obtain a bisaminophosphaphenanthrene material. The modified siloxane, the bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane and melamine undergo a nucleophilic substitution reaction at a mass ratio of 14.4:(2.5-2.7):1:(1.3-1.5) to obtain a flame retardant with excellent flame retardant properties. Then, the flame retardant with a certain amount of double bonds and the reinforced flame retardant rubber material and other raw materials are mixed (they can be co-vulcanized later), and the film is obtained through plasticizing, mixing, and calendering; the film includes an upper film, a lower film, and an intermediate film.

[0025] The present invention is distinguished by the fact that, in step three, the steel cord core is positioned as the center, and the intermediate film is wrapped around the core. The upper and lower sides of the intermediate film are respectively bonded with glass fiber cloth, and the outermost layers are provided with upper and lower films. The finished product is then cold-pressed and vulcanized to obtain the finished product. The finished product produced by the present invention has excellent flame retardancy and therefore has broad application prospects in the field of conveyor belt technology. DETAILED DESCRIPTION

[0026] The following will provide a clear and complete description of the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] Source of raw materials:

[0028] Natural rubber, provided by Lingshou County Jiaao Mineral Products Co., Ltd., with a specification of 2-4mm; butadiene rubber, provided by Dongguan Jiaqing Plastic Raw Materials Co., Ltd., with a viscosity of 50,000 molecular weight; octachloropropyl silsesquioxane, provided by Shanghai Aladdin Biochemical Technology Co., Ltd., with a molecular weight of 1036; steel wire rope core, provided by Nantong Changyuan Steel Rope Co., Ltd., with a diameter of 20mm; glass fiber cloth, provided by Kunshan Zhoushi Quande Packaging Materials Business Department, with a thickness of 1mm and a strength of 1000N.

[0029] Example 1: Step 1: S1: Under a nitrogen environment, eugenol is dissolved in tetrahydrofuran, and triethylamine is added and stirred thoroughly to obtain a eugenol solution; hexachlorocyclotriphosphazene is dissolved in tetrahydrofuran to obtain a hexachlorocyclotriphosphazene solution; the eugenol solution is allowed to stand at 3°C ​​for 8 minutes, and the hexachlorocyclotriphosphazene solution is added dropwise. After the addition is completed, stirring is continued at 30°C for 3.5 hours, and reflux reaction is carried out at 65°C for 8 hours. After the reaction is completed, the intermediate product is obtained by filtration, rotary evaporation, dissolution, washing, drying, and filtration; the reaction molar ratio of eugenol, triethylamine, and hexachlorocyclotriphosphazene is 6.7:4:1;

[0030] S2: Under a nitrogen environment, 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) was dissolved in ethyl acetate to obtain reaction solution 1; the intermediate product and azobisisobutyronitrile were dissolved in ethyl acetate to obtain reaction solution 2; reaction solution 2 was added dropwise to reaction solution 1, and after the addition was completed, the mixture was reacted at 75°C for 30 hours to obtain a thiol-terminated flame retardant material; the reaction molar ratio of 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) to the intermediate product was 6.4:1;

[0031] S3: 15 parts of mercapto-terminated flame retardant material were pre-mixed with 80 parts of natural rubber and 50 parts of butadiene rubber, and stirred at 75° C. for 2 h to obtain a reinforced flame retardant rubber material;

[0032] Step 2: S1: Under a nitrogen environment, dissolve eugenol in tetrahydrofuran, then add triethylamine and stir thoroughly to obtain a eugenol solution; dissolve octachloropropylsilsesquioxane in tetrahydrofuran to obtain a siloxane solution; let the eugenol solution stand at 3°C ​​for 8 minutes, then add the siloxane solution dropwise, continue stirring at 30°C for 3.5 hours after the addition is completed, and reflux at 70°C for 8 hours. After the reaction is completed, filter, rotary evaporate, dissolve, wash, dry, and filter to obtain a modified siloxane; the reaction mass ratio of eugenol, triethylamine, and octachloropropylsilsesquioxane is 9:6:14;

[0033] S2: Under a nitrogen environment, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid were mixed and stirred at 140°C for 30 hours. After the reaction, the mixture was precipitated, filtered, washed and vacuum-dried to obtain a bisaminophosphaphenanthrene material; the reaction mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid was 11:6:17:0.3;

[0034] S3: Add modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane, and melamine to N,N-dimethylformamide, heat and dissolve at 90°C for 30 minutes to obtain a mixed solution, and then react the mixed solution at a constant temperature of 105°C for 30 hours. After the reaction is completed, cool, filter, wash, and vacuum dry to obtain a flame retardant; the reaction mass ratio of modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane, and melamine is 14.4:2.6:1:1.4;

[0035] S4: 145 parts of a reinforced flame-retardant rubber material, 25 parts of a flame retardant, 4 parts of sulfur, 2 parts of zinc dibutyldithiocarbamate, 60 parts of carbon black, and 6 parts of N-phenyl-β-naphthylamine are mixed, and the mixture is plasticized, mixed, and calendered to obtain a film; the film includes an upper film, a lower film, and an intermediate film;

[0036] Step 3: Take the steel wire rope core as the center, and then wrap the middle film around the steel wire rope core. The upper and lower sides of the middle film are respectively adhered to the glass fiber cloth, and the upper and lower films are respectively set on the outermost sides. Then, cold pressing and vulcanization are performed to obtain the finished product; the cold pressing parameters are: pressure is 2.5MPa, time is 20min, temperature is 30℃; vulcanization parameters are: temperature is 160℃, time is 50min.

[0037] Example 2: Step 1: S1: Under a nitrogen environment, eugenol is dissolved in tetrahydrofuran, and triethylamine is added and stirred thoroughly to obtain a eugenol solution; hexachlorocyclotriphosphazene is dissolved in tetrahydrofuran to obtain a hexachlorocyclotriphosphazene solution; the eugenol solution is allowed to stand at 2°C for 7 minutes, and the hexachlorocyclotriphosphazene solution is added dropwise. After the addition is completed, stirring is continued at 27°C for 2 hours, and reflux reaction is carried out at 62°C for 7 hours. After the reaction is completed, the intermediate product is obtained by filtration, rotary evaporation, dissolution, washing, drying, and filtration; the reaction molar ratio of eugenol, triethylamine, and hexachlorocyclotriphosphazene is 6.7:4:1;

[0038] S2: Under a nitrogen environment, 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) was dissolved in ethyl acetate to obtain reaction solution 1; the intermediate product and azobisisobutyronitrile were dissolved in ethyl acetate to obtain reaction solution 2; reaction solution 2 was added dropwise to reaction solution 1, and after the addition was completed, the mixture was reacted at 72°C for 27 hours to obtain a thiol-terminated flame retardant material; the reaction molar ratio of 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) to the intermediate product was 6.4:1;

[0039] S3: 15 parts of the mercapto-terminated flame retardant material were pre-mixed with 80 parts of natural rubber and 50 parts of butadiene rubber, and the mixture was stirred and reacted at 72° C. for 1.5 hours to obtain a reinforced flame retardant rubber material;

[0040] Step 2: S1: Under a nitrogen environment, dissolve eugenol in tetrahydrofuran, then add triethylamine and stir thoroughly to obtain a eugenol solution; dissolve octachloropropylsilsesquioxane in tetrahydrofuran to obtain a siloxane solution; let the eugenol solution stand at 2°C for 7 minutes, then add the siloxane solution dropwise, continue stirring at 27°C for 3 hours after the addition is completed, reflux at 67°C for 7 hours, filter, rotary evaporate, dissolve, wash, dry, and filter to obtain a modified siloxane; the reaction mass ratio of eugenol, triethylamine, and octachloropropylsilsesquioxane is 9:6:14;

[0041] S2: Under a nitrogen environment, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid were mixed and stirred at 135°C for 27 hours. After the reaction, the mixture was precipitated, filtered, washed and vacuum-dried to obtain a bisaminophosphaphenanthrene material; the reaction mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid was 11:6:17:0.3;

[0042] S3: Add modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane, and melamine to N,N-dimethylformamide, heat and dissolve at 85°C for 25 minutes to obtain a mixed solution, and then react the mixed solution at a constant temperature of 100°C for 27 hours. After the reaction is completed, cool, filter, wash, and vacuum dry to obtain a flame retardant; the reaction mass ratio of modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane, and melamine is 14.4:2.6:1:1.4;

[0043] S4: 145 parts of a reinforced flame-retardant rubber material, 25 parts of a flame retardant, 4 parts of sulfur, 2 parts of zinc dibutyldithiocarbamate, 60 parts of carbon black, and 6 parts of N-phenyl-β-naphthylamine are mixed, and the mixture is plasticized, mixed, and calendered to obtain a film; the film includes an upper film, a lower film, and an intermediate film;

[0044] Step 3: Take the steel wire rope core as the center, and then wrap the middle film around the steel wire rope core. The upper and lower sides of the middle film are respectively adhered to the glass fiber cloth, and the upper and lower films are respectively set on the outermost sides. Then, cold pressing and vulcanization are performed to obtain the finished product; the cold pressing parameters are: pressure is 2.3MPa, time is 17min, temperature is 27℃; vulcanization parameters are: temperature is 150℃, time is 40min.

[0045] Example 3: Step 1: S1: Under a nitrogen environment, eugenol is dissolved in tetrahydrofuran, and triethylamine is added and stirred thoroughly to obtain a eugenol solution; hexachlorocyclotriphosphazene is dissolved in tetrahydrofuran to obtain a hexachlorocyclotriphosphazene solution; the eugenol solution is allowed to stand at 0°C for 5 minutes, and the hexachlorocyclotriphosphazene solution is added dropwise. After the addition is completed, stirring is continued at 25°C for 2.5 hours, and reflux reaction is carried out at 60°C for 6 hours. After the reaction is completed, the intermediate product is obtained by filtration, rotary evaporation, dissolution, washing, drying, and filtration; the reaction molar ratio of eugenol, triethylamine, and hexachlorocyclotriphosphazene is 6.7:4:1;

[0046] S2: Under a nitrogen environment, 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) was dissolved in ethyl acetate to obtain reaction solution 1; the intermediate product and azobisisobutyronitrile were dissolved in ethyl acetate to obtain reaction solution 2; reaction solution 2 was added dropwise to reaction solution 1, and after the addition was completed, the mixture was reacted at 70°C for 25 hours to obtain a thiol-terminated flame retardant material; the reaction molar ratio of 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) to the intermediate product was 6.4:1;

[0047] S3: 15 parts of mercapto-terminated flame retardant material were pre-mixed with 80 parts of natural rubber and 50 parts of butadiene rubber, and stirred at 70° C. for 1 hour to obtain a reinforced flame retardant rubber material;

[0048] Step 2: S1: Under a nitrogen environment, dissolve eugenol in tetrahydrofuran, then add triethylamine and stir thoroughly to obtain a eugenol solution; dissolve octachloropropylsilsesquioxane in tetrahydrofuran to obtain a siloxane solution; let the eugenol solution stand at 0°C for 5 minutes, then add the siloxane solution dropwise, continue stirring at 25°C for 2.5 hours after the addition is completed, and reflux at 65°C for 6 hours. After the reaction is completed, filter, rotary evaporate, dissolve, wash, dry, and filter to obtain a modified siloxane; the reaction mass ratio of eugenol, triethylamine, and octachloropropylsilsesquioxane is 9:6:14;

[0049] S2: Under a nitrogen environment, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid were mixed and stirred at 130°C for 25 hours. After the reaction, the mixture was precipitated, filtered, washed and vacuum-dried to obtain a bisaminophosphaphenanthrene material; the reaction mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid was 11:6:17:0.3;

[0050] S3: Add modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane, and melamine to N,N-dimethylformamide, heat and dissolve at 80°C for 20 minutes to obtain a mixed solution, and then react the mixed solution at a constant temperature of 95°C for 25 hours. After the reaction is completed, cool, filter, wash, and vacuum dry to obtain a flame retardant; the reaction mass ratio of modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane, and melamine is 14.4:2.6:1:1.4;

[0051] S4: 145 parts of a reinforced flame-retardant rubber material, 25 parts of a flame retardant, 4 parts of sulfur, 2 parts of zinc dibutyldithiocarbamate, 60 parts of carbon black, and 6 parts of N-phenyl-β-naphthylamine are mixed, and the mixture is plasticized, mixed, and calendered to obtain a film; the film includes an upper film, a lower film, and an intermediate film;

[0052] Step 3: Take the steel wire rope core as the center, and then wrap the middle film around the steel wire rope core. The upper and lower sides of the middle film are respectively adhered to the glass fiber cloth, and the upper and lower films are respectively set on the outermost sides. Then, cold pressing and vulcanization are performed to obtain the finished product; the cold pressing parameters are: pressure is 2.0MPa, time is 15min, temperature is 25℃; vulcanization parameters are: temperature is 140℃, time is 30min.

[0053] Comparative Example 1: The mercapto-terminated flame retardant material was removed, and the rest was the same as in Example 1, and the specific steps were as follows: Step 1: S1: Under a nitrogen environment, eugenol was dissolved in tetrahydrofuran, and triethylamine was added and stirred thoroughly to obtain a eugenol solution; octachloropropyl silsesquioxane was dissolved in tetrahydrofuran to obtain a siloxane solution; the eugenol solution was allowed to stand at 3° C. for 8 minutes, and the siloxane solution was added dropwise. After the addition was completed, stirring was continued at 30° C. for 3.5 hours, and refluxed at 70° C. for 8 hours. After the reaction was completed, the modified siloxane was obtained by filtering, rotary evaporation, dissolving, washing, drying, and filtering; the reaction mass ratio of eugenol, triethylamine, and octachloropropyl silsesquioxane was 9:6:14;

[0054] S2: Under a nitrogen environment, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid were mixed and stirred at 140°C for 30 hours. After the reaction, the mixture was precipitated, filtered, washed and vacuum-dried to obtain a bisaminophosphaphenanthrene material; the reaction mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid was 11:6:17:0.3;

[0055] S3: Add modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane, and melamine to N,N-dimethylformamide, heat and dissolve at 90°C for 30 minutes to obtain a mixed solution, and then react the mixed solution at a constant temperature of 105°C for 30 hours. After the reaction is completed, cool, filter, wash, and vacuum dry to obtain a flame retardant; the reaction mass ratio of modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane, and melamine is 14.4:2.6:1:1.4;

[0056] S4: 80 parts of natural rubber, 50 parts of butadiene rubber, 25 parts of flame retardant, 4 parts of sulfur, 2 parts of zinc dibutyl dithiocarbamate, 60 parts of carbon black, and 6 parts of N-phenyl-β-naphthylamine are mixed, and the mixture is plasticized, mixed, and calendered to obtain a film; the film includes an upper film, a lower film, and an intermediate film;

[0057] Step 2: Take the steel wire rope core as the center, and then wrap the middle film around the steel wire rope core. The upper and lower sides of the middle film are respectively adhered to the glass fiber cloth, and the upper and lower films are respectively set on the outermost sides. Then, cold pressing and vulcanization are performed to obtain the finished product; the cold pressing parameters are: pressure is 2.5MPa, time is 20min, temperature is 30℃; vulcanization parameters are: temperature is 160℃, time is 50min.

[0058] Comparative Example 2: The flame retardant was removed, and the rest was the same as in Example 1, and the specific steps were as follows: Step 1: S1: Under a nitrogen environment, eugenol was dissolved in tetrahydrofuran, and triethylamine was added, and the mixture was stirred thoroughly to obtain a eugenol solution; hexachlorocyclotriphosphazene was dissolved in tetrahydrofuran to obtain a hexachlorocyclotriphosphazene solution; the eugenol solution was allowed to stand at 3° C. for 8 minutes, and the hexachlorocyclotriphosphazene solution was added dropwise. After the addition was completed, stirring was continued at 30° C. for 3.5 hours, and the reaction was refluxed at 65° C. for 8 hours. After the reaction was completed, the mixture was filtered, rotary evaporated, dissolved, washed, dried, and filtered to obtain an intermediate product; the reaction molar ratio of eugenol, triethylamine, and hexachlorocyclotriphosphazene was 6.7:4:1;

[0059] S2: Under a nitrogen environment, 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) was dissolved in ethyl acetate to obtain reaction solution 1; the intermediate product and azobisisobutyronitrile were dissolved in ethyl acetate to obtain reaction solution 2; reaction solution 2 was added dropwise to reaction solution 1, and after the addition was completed, the mixture was reacted at 75°C for 30 hours to obtain a thiol-terminated flame retardant material; the reaction molar ratio of 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) to the intermediate product was 6.4:1;

[0060] S3: 15 parts of mercapto-terminated flame retardant material were pre-mixed with 80 parts of natural rubber and 50 parts of butadiene rubber, and stirred at 75° C. for 2 h to obtain a reinforced flame retardant rubber material;

[0061] Step 2: 145 parts of a reinforced flame-retardant rubber material, 4 parts of sulfur, 2 parts of zinc dibutyldithiocarbamate, 60 parts of carbon black, and 6 parts of N-phenyl-β-naphthylamine are mixed, and the mixture is plasticized, mixed, and calendered to obtain a film; the film includes an upper film, a lower film, and an intermediate film;

[0062] Step 3: Take the steel wire rope core as the center, and then wrap the middle film around the steel wire rope core. The upper and lower sides of the middle film are respectively adhered to the glass fiber cloth, and the upper and lower films are respectively set on the outermost sides. Then, cold pressing and vulcanization are performed to obtain the finished product; the cold pressing parameters are: pressure is 2.5MPa, time is 20min, temperature is 30℃; vulcanization parameters are: temperature is 160℃, time is 50min.

[0063] Comparative Example 3: The mercapto-terminated flame retardant material and the flame retardant were removed, and the rest was the same as in Example 1, and the specific steps were as follows: Step 1: 80 parts of natural rubber, 50 parts of butadiene rubber, 4 parts of sulfur, 2 parts of zinc dibutyldithiocarbamate, 60 parts of carbon black, and 6 parts of N-phenyl-β-naphthylamine were mixed, and the mixture was plasticized, mixed, and calendered to obtain a film; the film included an upper film, a lower film, and an intermediate film;

[0064] Step 2: Take the steel wire rope core as the center, and then wrap the middle film around the steel wire rope core. The upper and lower sides of the middle film are respectively adhered to the glass fiber cloth, and the upper and lower films are respectively set on the outermost sides. Then, cold pressing and vulcanization are performed to obtain the finished product; the cold pressing parameters are: pressure is 2.5MPa, time is 20min, temperature is 30℃; vulcanization parameters are: temperature is 160℃, time is 50min.

[0065] Detection test:

[0066] Limiting oxygen index test: referring to GB / T 10707-2008 “Determination of combustion properties of rubber”, the film prepared by the present invention was used as a sample with a sample size of 80×6.5×3 mm, and the oxygen index value was recorded.

[0067] Vertical burning test: referring to GB / T 10707-2008 “Determination of combustion properties of rubber”, the film prepared by the present invention is used as a sample with a sample size of 125×13×3 mm to determine the vertical burning grade.

[0068] Tensile strength test: Referring to GB / T 528-2009, "Rubber, vulcanized or thermoplastic — Determination of tensile stress and strain properties," the film prepared in this invention was used as a sample. The sample dimensions were: 120 mm in length, 25 mm in width at the end, 6 mm in width at the narrow portion, 35 mm in length at the narrow portion, and 2 mm in thickness. The tensile strength of the sample was tested. The results are shown in the following table:

[0069]

[0070] Conclusion: The dosage of Examples 1 to 3 remains unchanged, and only some reaction parameters are modified. From the experimental data, it can be seen that there is no significant fluctuation in the performance of the samples.

[0071] Comparative Example 1: The mercapto-terminated flame retardant material was removed, and the rest was the same as Example 1. From the experimental data, it can be seen that compared with Example 1, the oxygen index was reduced to 29%, and the tensile strength was reduced to 21.1 MPa. The reason was analyzed as follows: the mercapto-terminated flame retardant material contains a variety of flame retardant elements such as phosphorus and nitrogen, which can synergistically flame retardant. Therefore, after the mercapto-terminated flame retardant material was removed, the flame retardant performance was reduced.

[0072] Comparative Example 2: The flame retardant was removed, and the rest was the same as Example 1. From the experimental data, it can be seen that compared with Example 1, the oxygen index was reduced to 24%, and the tensile strength was reduced to 20.8 MPa. The reason for this is that the flame retardant contains a variety of flame retardant structures and flame retardant elements (phosphorus, nitrogen, silicon). Therefore, after removing it, the oxygen index is reduced and the tensile strength is reduced.

[0073] Comparative Example 3: The mercapto-terminated flame retardant material and flame retardant are removed, and the rest are the same as Example 1. It can be seen from the experimental data that compared with Example 1, the oxygen index is reduced to 20%, and the tensile strength is reduced to 20.2 MPa. The reason is analyzed as follows: Combining Comparative Examples 1 and 2, it can be seen that the mercapto-terminated flame retardant material and flame retardant have excellent flame retardant properties. Therefore, after removing them, the flame retardant properties are significantly reduced.

[0074] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0075] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A process for preparing a flame-retardant steel cord conveyor belt, characterized in that: The following steps are involved: Step 1: pre-mix the mercapto-terminated flame retardant material with natural rubber and butadiene rubber, and stir and react at 70-75° C. for 1-2 hours to obtain a reinforced flame retardant rubber material; Step 2: Mixing the flame retardant reinforced rubber material, flame retardant, vulcanizing agent, accelerator, reinforcing agent and antioxidant, and performing plasticizing, mixing and calendering to obtain a film; the film includes an upper film, a lower film and an intermediate film; Step 3: Take the steel wire rope core as the center, and then wrap the middle film around the steel wire rope core. The upper and lower sides of the middle film are respectively attached to the glass fiber cloth, and the upper and lower films are respectively set on the outermost sides. Then, it is cold pressed and vulcanized to obtain the finished product.

2. The process for preparing a flame-retardant steel cord conveyor belt according to claim 1, characterized in that: In step 1, the contents of the components of the reinforced flame retardant rubber material are as follows: by mass: 60-80 parts of natural rubber, 40-50 parts of butadiene rubber, and 10-15 parts of mercapto-terminated flame retardant material.

3. The process for preparing a flame-retardant steel cord conveyor belt according to claim 2, characterized in that: The preparation process of mercapto-terminated flame retardant material is as follows: S1: Under a nitrogen atmosphere, eugenol is dissolved in tetrahydrofuran, triethylamine is added, and the mixture is stirred thoroughly to obtain a eugenol solution; hexachlorocyclotriphosphazene is dissolved in tetrahydrofuran to obtain a hexachlorocyclotriphosphazene solution; the eugenol solution is allowed to stand at 0-3°C for 5-8 minutes, and the hexachlorocyclotriphosphazene solution is added dropwise. After the addition is completed, stirring is continued at 25-30°C for 2.5-3.5 hours, and the mixture is refluxed at 60-65°C for 6-8 hours. After the reaction is completed, the mixture is filtered, rotary evaporated, dissolved, washed, dried, and filtered to obtain an intermediate product; S2: Under a nitrogen environment, dissolve 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) in ethyl acetate to obtain reaction solution 1; dissolve the intermediate product and azobisisobutyronitrile in ethyl acetate to obtain reaction solution 2; add reaction solution 2 dropwise to reaction solution 1, and react at 70-75°C for 25-30 hours after the addition is completed to obtain a thiol-terminated flame retardant material.

4. The process for preparing a flame-retardant steel cord conveyor belt according to claim 3, characterized in that: When preparing the intermediate product, the reaction molar ratio of eugenol, triethylamine, and hexachlorocyclotriphosphazene is (6.5-7.0):4:1; when preparing the thiol-terminated flame retardant material, the reaction molar ratio of 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan) and the intermediate product is (6.3-6.5):

1.

5. The process for preparing a flame-retardant steel cord conveyor belt according to claim 1, characterized in that: In step 2, the contents of the components of the film are: by mass, 110-145 parts of reinforced flame retardant rubber material, 20-25 parts of flame retardant, 3-4 parts of vulcanizing agent, 1-2 parts of accelerator, 40-60 parts of reinforcing agent, and 4-6 parts of antioxidant; the vulcanizing agent is sulfur; the accelerator is zinc dibutyldithiocarbamate; the reinforcing agent is carbon black; and the antioxidant is N-phenyl-β-naphthylamine.

6. The process for preparing a flame-retardant steel cord conveyor belt according to claim 5, characterized in that: The preparation process of flame retardant is: S1: Under a nitrogen atmosphere, eugenol is dissolved in tetrahydrofuran, and triethylamine is added and stirred thoroughly to obtain a eugenol solution; octachloropropylsilsesquioxane is dissolved in tetrahydrofuran to obtain a siloxane solution; the eugenol solution is allowed to stand at 0-3°C for 5-8 minutes, and the siloxane solution is added dropwise. After the addition is completed, stirring is continued at 25-30°C for 2.5-3.5 hours, and reflux reaction is carried out at 65-70°C for 6-8 hours. After the reaction is completed, the modified siloxane is obtained by filtering, rotary evaporation, dissolving, washing, drying, and filtering. S2: Under a nitrogen environment, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline and p-toluenesulfonic acid are mixed and stirred at 130-140° C. for 25-30 hours. After the reaction, the mixture is precipitated, filtered, washed and vacuum dried to obtain a bisaminophosphaphenanthrene material; S3: Add modified siloxane, bisaminophosphaphenanthrene material, 4,4'-diaminodiphenylmethane and melamine to N,N-dimethylformamide, heat and dissolve at 80-90°C for 20-30 minutes to obtain a mixed solution, and then react the mixed solution at a constant temperature of 95-105°C for 25-30 hours. After the reaction is completed, cool, filter, wash and vacuum dry to obtain a flame retardant.

7. The process for preparing a flame-retardant steel cord conveyor belt according to claim 6, characterized in that: When preparing modified silicone, the reaction mass ratio of eugenol, triethylamine, and octachloropropylsilsesquioxane is 9:6:(13-15); when preparing bisaminophosphaphenanthrene materials, the reaction mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-aminoacetophenone, aniline, and p-toluenesulfonic acid is (10-12):6:17:0.3; when preparing flame retardants, the reaction mass ratio of modified silicone, bisaminophosphaphenanthrene materials, 4,4'-diaminodiphenylmethane, and melamine is 14.4:(2.5-2.7):1:(1.3-1.5).

8. The process for preparing a flame-retardant steel cord conveyor belt according to claim 1, characterized in that: In step 3, the cold pressing parameters are: pressure 2.0-2.5 MPa, time 15-20 min, temperature 25-30° C.; the vulcanization parameters are: temperature 140-160° C., time 30-50 min.

9. A flame-retardant steel cord conveyor belt, characterized in that: Prepared according to the preparation process according to any one of claims 1 to 8.

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