Coal mine underground flame-retardant aramid fiber rope conveyor belt and preparation method thereof

Abstract

The present application belongs to the technical field of conveying belt, and particularly relates to a coal mine underground flame-retardant aramid rope conveying belt and a preparation method thereof. The present application comprises an aramid framework formed by arranging a plurality of aramid ropes and a covering rubber coated on the outside of the aramid framework, the aramid ropes constituting the aramid framework are connected by intermediate rubber, and the aramid framework and the covering rubber are connected by intermediate rubber; the aramid ropes are treated by solvent immersion and ultraviolet lamp irradiation; the raw material components of the covering rubber contain epoxidized butyronitrile rubber; the raw material components of the intermediate rubber contain an adhesive; the adhesive is prepared by reacting dienyl bisphenol A diglycidyl ether and end hydrogen-containing fluorosilicone oil under the catalysis of a platinum catalyst and with gamma-(methacryloyloxy)propyl trimethoxysilane. The present application introduces intermediate rubber, which is combined with the aramid framework and the covering rubber, has high bonding strength, and prolongs the service life of the conveying belt.

Description

Technical Field

[0001] This invention belongs to the field of conveyor belt technology, specifically relating to flame-retardant aramid rope conveyor belts for underground coal mines and their preparation methods. Background Technology

[0002] Flame-retardant conveyor belts for underground coal mines are key components for material transportation in underground mines. They feature large capacity, long distance, high speed, impact resistance, low elongation, and long service life, and are widely used in the transportation of materials such as coal, ore, and slag.

[0003] Traditional flame-retardant conveyor belts used in underground coal mines primarily employ steel wire rope as their skeleton material. However, steel wire rope conveyor belts suffer from problems such as low joint strength, heavy weight, and high energy consumption. Aramid fiber, a new type of high-tech synthetic fiber, possesses excellent properties including ultra-high strength, high modulus, high temperature resistance, flame retardancy, acid and alkali resistance, and light weight. Its strength is approximately 4-5 times that of steel wire, its modulus is 2-3 times that of steel wire or glass fiber, its toughness is twice that of steel wire, while its weight is only about 1 / 5 that of steel wire. Furthermore, it does not decompose or melt at temperatures up to 560℃. Replacing steel wire rope with aramid rope as the skeleton material can effectively solve the joint problem of traditional steel wire rope conveyor belts and improve the overall strength of the conveyor belt. However, aramid fibers have a chemically inert surface and weak interfacial bonding with the rubber matrix. In contrast, the harsh working conditions in coal mines, where conveyor belts are subjected to material impacts, repeated bending, moisture, and corrosive gas erosion, make the interface between the aramid rope and the rubber matrix more prone to peeling failure. This seriously affects the operational safety and reliability of the conveyor belt and may even lead to production accidents, thus restricting the widespread application of aramid rope conveyor belts in coal mines. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a flame-retardant aramid rope conveyor belt for underground coal mines. An intermediate rubber is introduced, which bonds to the aramid skeleton and the cover rubber, resulting in high bonding strength and extending the conveyor belt's service life. This invention also provides a method for its preparation.

[0005] The flame-retardant aramid rope conveyor belt for underground coal mines according to the present invention includes an aramid skeleton composed of multiple aramid ropes and a cover rubber covering the outside of the aramid skeleton. The aramid ropes that make up the aramid skeleton and the aramid skeleton and the cover rubber are connected by an intermediate rubber.

[0006] The aramid rope is treated with solvent impregnation and ultraviolet light irradiation;

[0007] The raw material components of the cover rubber contain epoxidized nitrile rubber;

[0008] The raw material components of the intermediate adhesive contain an adhesive;

[0009] The adhesive is prepared by reacting diallyl bisphenol A diglycidyl ether and hydrofluoric acid-terminated silicone oil with γ-(methacryloyloxy)propyltrimethoxysilane under the catalysis of a platinum catalyst.

[0010] Preferably, the aramid rope is made of strands of aramid filaments twisted together; the solvent is acetone, and the aramid rope is pretreated by immersion in acetone to clean the surface of the aramid rope and remove the treatment agents and impurities from the fiber during processing, so as to facilitate subsequent ultraviolet light modification; the immersion time is preferably 2 hours, and after immersion, the solvent is removed by heat drying at 60-70°C; the ultraviolet lamp irradiation time is 5-8 minutes.

[0011] Preferably, the method for preparing the adhesive includes the following steps:

[0012] (1) Mix a toluene solution of diallyl bisphenol A diglycidyl ether with hydrofluoric acid-terminated silicone oil, then add a platinum catalyst and heat the mixture to react.

[0013] (2) Add γ-(methacryloyloxy)propyltrimethoxysilane, and remove toluene after the reaction to obtain the product.

[0014] Preferably, the molar ratio of diallyl bisphenol A diglycidyl ether to hydrofluorosilicone oil is less than 1, and the ratio of the sum of the molar numbers of diallyl bisphenol A diglycidyl ether and γ-(methacryloyloxy)propyltrimethoxysilane to the molar number of hydrofluorosilicone oil is greater than 1; the amount of platinum catalyst is 0.18% of the mass of hydrofluorosilicone oil; in steps (1) and (2), the reaction temperature is 80-90℃ and the reaction time is 1.5-2.5h.

[0015] Preferably, the raw material components of the cover rubber include styrene-butadiene rubber, rare earth cis-butadiene rubber, epoxidized nitrile rubber, vulcanizing agent, accelerator, activator, reinforcing agent, dispersant, antioxidant, flame retardant and flame retardant synergist;

[0016] The raw material components of intermediate rubber include styrene-butadiene rubber, butadiene rubber, adhesive, vulcanizing agent, accelerator, activator, reinforcing agent, dispersant, antioxidant, flame retardant and flame retardant synergist.

[0017] Preferably, the proportion of raw materials used in the cover adhesive by weight is as follows:

[0018] 65-80 parts of styrene-butadiene rubber,

[0019] 0-8 parts of butadiene rubber

[0020] 15-20 parts of rare earth butadiene rubber

[0021] 5-10 parts of epoxidized nitrile butadiene rubber,

[0022] 2.5-4 parts vulcanizing agent,

[0023] Accelerator 2-3 parts,

[0024] 5-10 parts of surfactant

[0025] 40-50 parts of reinforcing agent

[0026] 2-3 parts dispersant

[0027] Anti-aging agent 2-3.5 parts,

[0028] 20-35 parts flame retardant

[0029] 3-5 parts of flame retardant synergist;

[0030] The proportions of raw materials used in the intermediate rubber, by weight, are as follows:

[0031] 62-72 parts of styrene-butadiene rubber,

[0032] 18-28 parts of butadiene rubber,

[0033] 8-12 parts of adhesive,

[0034] 2-3 parts of vulcanizing agent

[0035] Accelerator 1-1.8 parts,

[0036] Surfactant 6-8 parts,

[0037] 35-40 parts of reinforcing agent

[0038] Dispersant 1.5-2 parts,

[0039] Anti-aging agent 1.5-2.5 parts,

[0040] 12-14 parts flame retardant

[0041] 1-2 parts of flame retardant synergist.

[0042] Among them, rare earth butadiene rubber is a type of butadiene rubber polymerized using a catalyst system with neodymium as the main rare earth metal. Its strength and wear resistance are superior to ordinary butadiene rubber, with Lanxess's BR CB22 being the preferred choice.

[0043] Preferably, the vulcanizing agent is sulfur, the accelerator is a compound of accelerator CZ and accelerator DM in a mass ratio of (2-3):1, the activator is zinc oxide and stearic acid in a mass ratio of 3:2, the reinforcing agent is carbon black, the dispersant is silicon 69, and the antioxidant is antioxidant RD, antioxidant 4010NA and microcrystalline wax in a mass ratio of (1-1.5):(1-1.5):0.5.

[0044] Preferably, the flame retardant is MCA and decabromodiphenyl ethane in a mass ratio of 1:(3-5), and the flame retardant synergist is antimony trioxide.

[0045] Preferably, the preparation method of epoxidized nitrile butadiene rubber is as follows: nitrile butadiene rubber is dissolved in chlorobenzene, acetic acid and hydrogen peroxide are added, the mixture is heated to react, cooled, washed with anhydrous ethanol, and dried to obtain epoxidized nitrile butadiene rubber; wherein the molar ratio of nitrile butadiene rubber, acetic acid and hydrogen peroxide is 1:2:4.

[0046] Preferably, the molecular formula of the end-containing hydrofluoric silicone oil is as follows, where n is 10-20;

[0047] .

[0048] The preparation method of the flame-retardant aramid rope conveyor belt for underground coal mines according to the present invention includes the following steps:

[0049] S1, a stage of mixing:

[0050] S1-1. Styrene-butadiene rubber, butadiene rubber, rare earth butadiene rubber, and epoxidized nitrile rubber are added to a mixer and mixed for 50-90 seconds. Then, activators, antioxidants, flame retardants, and flame retardant synergists are added to the mixer and mixed for another 40-80 seconds. Then, dispersants and reinforcing agents are added and mixed for another 160-220 seconds. The top plug is raised and lowered. When the mixture in the mixer reaches 120-135°C, the bottom plug is opened and the mixed rubber is discharged to a sheeting machine for further mixing for 180-260 seconds. Then, the sheet is discharged, cooled, and the first stage of the cover rubber compound is obtained.

[0051] S1-2. Styrene-butadiene rubber and butadiene rubber are put into an internal mixer and mixed for 50-90 seconds. Then, activator, antioxidant, flame retardant and flame retardant synergist are added to the internal mixer and mixed for another 40-80 seconds. Then, dispersant, reinforcing agent and binder are added and mixed for another 120-200 seconds. The top plug is raised and lowered. When the mixture in the internal mixer reaches 115-130°C, the bottom plug is opened and the mixed rubber is discharged to the sheeting machine for further mixing for 180-260 seconds. Then, the sheet is discharged and cooled to obtain the intermediate rubber first stage mixed rubber.

[0052] S2, Two-stage mixing:

[0053] S2-1. The cooled cover rubber first-stage compound is put into an internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 120-200 seconds. When the rubber temperature in the internal mixer reaches 85-95℃, the bottom top plug is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 180-260 seconds, then sheeted and cooled to obtain the cover rubber second-stage compound.

[0054] S2-2. The cooled intermediate rubber section 1 compound is put into the internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 120-200 seconds. When the rubber temperature in the internal mixer reaches 80-90℃, the bottom top plug is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 180-260 seconds, then sheeted and cooled to obtain intermediate rubber section 2.

[0055] S3, composite, vulcanized:

[0056] A composite film is obtained by bonding an intermediate adhesive and a second-stage adhesive to both sides of an aramid skeleton, and then bonding a cover adhesive and a second-stage adhesive to the outside of the intermediate adhesive and the second-stage adhesive. The composite film is then vulcanized to obtain the final product.

[0057] Preferably, in the vulcanization of the composite film, the vulcanization temperature is 145-155℃, the vulcanization pressure is 16-20MPa, and the vulcanization time is 25-35min.

[0058] Compared with the prior art, the beneficial effects of the present invention are:

[0059] 1. Irradiation with ultraviolet light increases the surface roughness and surface activity of aramid fibers, providing active sites for chemical grafting.

[0060] 2. This invention provides a self-made adhesive. First, a fluorinated block silicone oil containing bisphenol A diglycidyl ether with silane-hydrogen bonds at both ends is obtained by reacting diallyl bisphenol A diglycidyl ether with hydrofluoric acid-terminated silicone oil. Then, it is capped by reacting with γ-(methacryloyloxy)propyltrimethoxysilane to obtain an alkoxy-capped fluorinated polysiloxane, forming a "molecular bridge". Its siloxane groups can react with the surface-active groups of aramid fibers, and the ester bonds in the molecule can also easily form hydrogen bonds with the aramid surface. Through chemical bonding and physical anchoring, the bonding force with the aramid rope is increased. The epoxy groups can participate in the vulcanization of rubber and also bond with the aramid surface. Therefore, the addition of the adhesive significantly increases the bonding strength between the aramid rope and the intermediate rubber. The introduction of epoxy groups and bisphenol A structure into the molecular block helps to improve aging resistance. At the same time, fluorine and silicon elements with flame-retardant properties are also introduced, which work synergistically with the added flame retardant to increase the flame-retardant effect and reduce the amount of flame retardant used, thereby saving costs.

[0061] 3. The cover rubber contains epoxidized nitrile rubber, which retains the original oil resistance and wear resistance of nitrile rubber while introducing active epoxy groups. At the same time, the adhesive of the intermediate rubber also contains epoxy groups. During vulcanization, the epoxy groups at both locations work synergistically at the interface, increasing the interfacial bonding strength between the cover rubber and the intermediate rubber. Detailed Implementation

[0062] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments.

[0063] Unless otherwise specified, all raw materials used in the examples and comparative examples were commercially available.

[0064] Aramid rope, 5.5mm in diameter, 3300DTEX / 2×3×6, twist 50TPM;

[0065] Styrene-butadiene rubber, SBR 1500, China Petroleum & Chemical Corporation;

[0066] Butadiene rubber, BR 9000, China Petroleum & Chemical Corporation;

[0067] Rare earth butadiene rubber, BR CB22, Arlanxtech High Performance Elastomers (Changzhou) Co., Ltd.;

[0068] Reinforcing agent, carbon black N220;

[0069] The preparation method of epoxidized nitrile butadiene rubber is as follows: nitrile butadiene rubber is dissolved in chlorobenzene, acetic acid and hydrogen peroxide are added, the temperature is raised to 60℃, the reaction is kept at this temperature for 6 hours, the temperature is cooled to 25℃, washed three times with anhydrous ethanol, and dried to obtain epoxidized nitrile butadiene rubber (epoxy degree 20%); wherein, the molar ratio of nitrile butadiene rubber, acetic acid and hydrogen peroxide is 1:2:4.

[0070] The preparation method of adhesive a includes the following steps:

[0071] (1) Dissolve 0.8 mol diallyl bisphenol A diglycidyl ether in toluene to obtain a toluene solution. Add 1 mol of end-containing hydrofluoric silicone oil (Mn=2006 g / mol) to the reactor and stir. Add the toluene solution to the reactor while stirring. Then add 3.61 g of chloroplatinic acid catalyst to the reactor dropwise. Stir for 30 min, raise the temperature to 90 °C, and stir for 1.5 h.

[0072] (2) Add 0.7 mol γ-(methacryloyloxy)propyltrimethoxysilane, maintain the reaction at 90℃ for 1.5 h, remove toluene at 90℃ and vacuum degree -0.08 MPa to obtain the product.

[0073] The preparation method of adhesive b includes the following steps:

[0074] (1) Dissolve 0.6 mol diallyl bisphenol A diglycidyl ether in toluene to obtain a toluene solution. Add 1 mol of hydrofluoric acid-containing silicone oil (Mn=1694 g / mol) to the reactor and stir. Add the toluene solution to the reactor while stirring. Then add 3.05 g of chloroplatinic acid catalyst to the reactor dropwise. Stir for 30 min, raise the temperature to 85 °C, and stir for 2 h.

[0075] (2) Add 1 mol of γ-(methacryloyloxy)propyltrimethoxysilane, maintain the reaction at 85°C for 2 h, remove toluene at 85°C and vacuum degree -0.08 MPa to obtain the product.

[0076] The preparation method of adhesive c includes the following steps:

[0077] (1) Dissolve 0.9 mol diallyl bisphenol A diglycidyl ether in toluene to obtain a toluene solution. Add 1 mol of hydrofluoric acid-containing silicone oil (Mn=2630 g / mol) to the reactor and stir. Add the toluene solution to the reactor while stirring. Then add 4.73 g of chloroplatinic acid catalyst to the reactor dropwise. Stir for 30 min, raise the temperature to 85 °C, and stir for 2 h.

[0078] (2) Add 0.5 mol γ-(methacryloyloxy)propyltrimethoxysilane, maintain the reaction at 85℃ for 2 h, remove toluene at 85℃ and vacuum degree -0.08 MPa to obtain the product.

[0079] The preparation method of adhesive d includes the following steps:

[0080] (1) Dissolve 0.6 mol diallyl bisphenol A diglycidyl ether in toluene to obtain a toluene solution. Add 1 mol of hydrofluoric acid-containing silicone oil (Mn=3254 g / mol) to the reactor and stir. Add the toluene solution to the reactor while stirring. Then add 5.85 g of chloroplatinic acid catalyst to the reactor dropwise. Stir for 30 min, raise the temperature to 80 °C, and stir for 2.5 h.

[0081] (2) Add 0.8 mol γ-(methacryloyloxy)propyltrimethoxysilane, maintain the reaction at 80℃ for 2.5 h, remove toluene at 80℃ and vacuum degree -0.08 MPa to obtain the product.

[0082] Example 1

[0083] The flame-retardant aramid rope conveyor belt for underground coal mines, the cover rubber, and the proportion of raw materials used by weight are as follows:

[0084] 65 parts of styrene-butadiene rubber,

[0085] 8 parts of butadiene rubber,

[0086] 17 parts of rare earth butadiene rubber

[0087] 10 parts of epoxidized nitrile rubber,

[0088] 2.5 parts sulfur

[0089] Accelerator CZ 2 parts,

[0090] Accelerator DM 1 part,

[0091] 3 parts zinc oxide

[0092] 2 parts stearic acid

[0093] Carbon black N220 40 parts

[0094] Silicon 69 3 parts,

[0095] Anti-aging agent RD 1 part,

[0096] Anti-aging agent 4010NA 1 part,

[0097] 0.5 parts microcrystalline wax

[0098] 5 parts of flame retardant MCA

[0099] 15 parts of decabromodiphenyl ethane

[0100] 3 parts antimony dioxide;

[0101] The proportions of raw materials used in the intermediate rubber, by weight, are as follows:

[0102] 62 parts of styrene-butadiene rubber,

[0103] 28 parts of butadiene rubber,

[0104] 10 parts of adhesive a

[0105] 2 parts sulfur

[0106] Accelerator CZ 0.75 parts,

[0107] Accelerator DM 0.25 parts,

[0108] 3.6 parts zinc oxide

[0109] Stearic acid 2.4 parts,

[0110] Carbon black N220 35 parts

[0111] Silicon 69, 1.5 parts

[0112] Anti-aging agent RD 1 part,

[0113] Anti-aging agent 4010NA 1 part,

[0114] 0.5 parts microcrystalline wax

[0115] 3 parts of flame retardant MCA

[0116] 9 parts of decabromodiphenyl ethane

[0117] 1 part antimony dioxide.

[0118] Aramid rope pretreatment: The aramid rope was immersed in acetone for 2 hours, then dried at 65°C to remove the solvent, and irradiated with a 400W ultraviolet lamp for 5 minutes.

[0119] The preparation method of the flame-retardant aramid rope conveyor belt for underground coal mines includes the following steps:

[0120] S1, a stage of mixing:

[0121] S1-1. Styrene-butadiene rubber, butadiene rubber, rare earth butadiene rubber, and epoxidized nitrile rubber are added to a mixer and mixed for 70 seconds. Then, activator, antioxidant, flame retardant, and flame retardant synergist are added to the mixer and the mixing continues for 60 seconds. Then, dispersant and reinforcing agent are added and the mixing continues for 190 seconds. The top plug is raised and lowered. When the mixture in the mixer reaches 130°C, the bottom plug is opened and the compound is discharged to a sheeting machine for further mixing for 220 seconds. Then, the sheet is discharged, cooled, and the first stage of the cover rubber compound is obtained.

[0122] S1-2. Styrene-butadiene rubber and butadiene rubber are put into an internal mixer and mixed for 70 seconds. Then, activator, antioxidant, flame retardant and flame retardant synergist are added to the internal mixer and mixed for another 60 seconds. Then, dispersant, reinforcing agent and binder are added and mixed for another 170 seconds. The top plug is raised and lowered. When the mixture in the internal mixer reaches 125°C, the bottom plug is opened and the mixed rubber is discharged to the sheeting machine for further mixing for 220 seconds. Then, the sheet is discharged and cooled to obtain the intermediate rubber first stage mixed rubber.

[0123] S2, Two-stage mixing:

[0124] S2-1. The cooled cover rubber first-stage compound is put into an internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 180 seconds. When the rubber temperature in the internal mixer reaches 92°C, the bottom top bolt is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 220 seconds, then sheeted and cooled to obtain the cover rubber second-stage compound.

[0125] S2-2. The cooled intermediate rubber section 1 compound is put into the internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 180 seconds. When the rubber temperature in the internal mixer reaches 88°C, the bottom top bolt is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 220 seconds, then sheeted and cooled to obtain intermediate rubber section 2.

[0126] S3, composite, vulcanized:

[0127] A composite film is obtained by bonding the intermediate adhesive and the second-stage adhesive to both sides of the aramid skeleton, and then bonding the outer side of the intermediate adhesive and the second-stage adhesive to the cover adhesive and the second-stage adhesive; the composite film is then vulcanized to obtain the final product.

[0128] In the vulcanization of the composite film, the vulcanization temperature is 152℃, the vulcanization pressure is 19MPa, and the vulcanization time is 32min.

[0129] Example 2

[0130] The flame-retardant aramid rope conveyor belt for underground coal mines, the cover rubber, and the proportion of raw materials used by weight are as follows:

[0131] 75 parts of styrene-butadiene rubber,

[0132] 5 parts butadiene rubber

[0133] 15 parts of rare earth butadiene rubber

[0134] 5 parts of epoxidized nitrile butadiene rubber,

[0135] Sulfur 3 parts,

[0136] Accelerator CZ 1.5 parts,

[0137] Accelerator DM 0.5 parts,

[0138] 3.6 parts zinc oxide

[0139] Stearic acid 2.4 parts,

[0140] Carbon black N220 45 parts

[0141] Dispersant Si69 2 parts,

[0142] Anti-aging agent RD 1 part,

[0143] Anti-aging agent 4010NA 1.5 parts,

[0144] 0.5 parts microcrystalline wax

[0145] 5 parts of flame retardant MCA

[0146] 20 parts of decabromodiphenyl ethane

[0147] 3 parts antimony trioxide;

[0148] The proportions of raw materials used in the intermediate rubber, by weight, are as follows:

[0149] 66 parts of styrene-butadiene rubber,

[0150] 24 parts of butadiene rubber,

[0151] Adhesive b 10 parts,

[0152] 2 parts sulfur

[0153] Accelerator CZ 1 part,

[0154] Accelerator DM 0.5 parts,

[0155] 4.8 parts zinc oxide

[0156] Stearic acid 3.2 parts,

[0157] Carbon black N220 35 parts

[0158] Si69 1.5 parts,

[0159] Anti-aging agent RD 0.8 parts,

[0160] Anti-aging agent 4010NA 0.8 parts,

[0161] 0.4 parts microcrystalline wax

[0162] Flame retardant MCA 2 parts,

[0163] 10 parts of decabromodiphenyl ethane

[0164] 1 part of antimony trioxide.

[0165] Aramid rope pretreatment: The aramid rope was immersed in acetone for 2 hours, then dried at 60°C to remove the solvent, and irradiated with a 300W ultraviolet lamp for 8 minutes.

[0166] The preparation method of the flame-retardant aramid rope conveyor belt for underground coal mines includes the following steps:

[0167] S1, a stage of mixing:

[0168] S1-1. Styrene-butadiene rubber, butadiene rubber, rare earth butadiene rubber, and epoxidized nitrile rubber are added to a mixer and mixed for 60 seconds. Then, activator, antioxidant, flame retardant, and flame retardant synergist are added to the mixer and mixed for another 50 seconds. Then, dispersant and reinforcing agent are added and mixed for another 180 seconds. The top plug is raised and lowered. When the mixture in the mixer reaches 125°C, the bottom plug is opened and the mixed rubber is discharged to a sheeting machine for further mixing for 200 seconds. Then, the sheet is discharged, cooled, and the first stage of the cover rubber mixed rubber is obtained.

[0169] S1-2. Styrene-butadiene rubber and butadiene rubber are put into an internal mixer and mixed for 60 seconds. Then, activator, antioxidant, flame retardant and flame retardant synergist are added to the internal mixer and mixed for another 50 seconds. Then, dispersant, reinforcing agent and binder are added and mixed for another 160 seconds. The top plug is raised and lowered. When the mixture in the internal mixer reaches 120°C, the bottom plug is opened and the mixed rubber is discharged to the sheeting machine for further mixing for 200 seconds. Then, the sheet is discharged and cooled to obtain the intermediate rubber first stage mixed rubber.

[0170] S2, Two-stage mixing:

[0171] S2-1. The cooled cover rubber first-stage compound is put into an internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 150 seconds. When the rubber temperature in the internal mixer reaches 90°C, the bottom top bolt is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for another 200 seconds, then sheeted and cooled to obtain the cover rubber second-stage compound.

[0172] S2-2. The cooled intermediate rubber section 1 compound is put into the internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 150 seconds. When the rubber temperature in the internal mixer reaches 85°C, the bottom top bolt is opened and the compound is discharged onto the sheeting machine. The mixture is then mixed for another 200 seconds, then sheeted and cooled to obtain intermediate rubber section 2.

[0173] S3, composite, vulcanized:

[0174] A composite film is obtained by bonding an intermediate adhesive and a second-stage adhesive to both sides of an aramid skeleton, and then bonding a cover adhesive and a second-stage adhesive to the outside of the intermediate adhesive and the second-stage adhesive. The composite film is then vulcanized to obtain the final product.

[0175] In the vulcanization of composite film, the vulcanization temperature is 150℃, the vulcanization pressure is 18MPa, and the vulcanization time is 30min.

[0176] Example 3

[0177] The flame-retardant aramid rope conveyor belt for underground coal mines, the cover rubber, and the proportion of raw materials used by weight are as follows:

[0178] 80 parts of styrene-butadiene rubber,

[0179] 15 parts of rare earth butadiene rubber

[0180] 5 parts of epoxidized nitrile butadiene rubber,

[0181] Sulfur 4 parts,

[0182] Accelerator CZ 1.5 parts,

[0183] Accelerator DM 0.5 parts,

[0184] 6 parts zinc oxide

[0185] 4 parts stearic acid

[0186] Carbon black N220 50 parts

[0187] Si69 3 portions,

[0188] Anti-aging agent RD 1.5 parts,

[0189] Anti-aging agent 4010NA 1.5 parts,

[0190] 0.5 parts microcrystalline wax

[0191] 7 parts of flame retardant MCA

[0192] 28 parts of decabromodiphenyl ethane

[0193] 5 parts antimony dioxide;

[0194] The proportions of raw materials used in the intermediate rubber, by weight, are as follows:

[0195] 70 parts of styrene-butadiene rubber,

[0196] 22 parts of butadiene rubber,

[0197] Adhesive c 8 parts,

[0198] 2.5 parts sulfur

[0199] Accelerator CZ 1.2 parts,

[0200] Accelerator DM 0.6 parts,

[0201] 4.8 parts zinc oxide

[0202] Stearic acid 3.2 parts,

[0203] Carbon black N220 40 parts

[0204] Si69 1.5 parts,

[0205] Anti-aging agent RD 1 part,

[0206] Anti-aging agent 4010NA 1 part,

[0207] 0.5 parts microcrystalline wax

[0208] 3 parts of flame retardant MCA

[0209] 9 parts of decabromodiphenyl ethane

[0210] Two parts of antimony trioxide.

[0211] Aramid rope pretreatment: The aramid rope was immersed in acetone for 2 hours, then dried at 70°C to remove the solvent, and irradiated with a 350W ultraviolet lamp for 6 minutes.

[0212] The preparation method of the flame-retardant aramid rope conveyor belt for underground coal mines includes the following steps:

[0213] S1, a stage of mixing:

[0214] S1-1. Styrene-butadiene rubber, rare earth butadiene rubber, and epoxidized nitrile rubber are added to a mixer and mixed for 80 seconds. Then, activator, antioxidant, flame retardant, and flame retardant synergist are added to the mixer and mixed for another 70 seconds. Then, dispersant and reinforcing agent are added and mixed for another 220 seconds. The top plug is raised and lowered. When the mixture in the mixer reaches 135°C, the bottom plug is opened and the mixed rubber is discharged to a sheeting machine for further mixing for 260 seconds. Then, the sheet is discharged, cooled, and the first stage of the cover rubber mixed rubber is obtained.

[0215] S1-2. Styrene-butadiene rubber and butadiene rubber are put into an internal mixer and mixed for 80 seconds. Then, activator, antioxidant, flame retardant and flame retardant synergist are added to the internal mixer and mixed for another 70 seconds. Then, dispersant, reinforcing agent and binder are added and mixed for another 200 seconds. The top plug is raised and lowered. When the mixture in the internal mixer reaches 130°C, the bottom plug is opened and the mixed rubber is discharged to the sheeting machine and mixed for another 260 seconds. Then, the sheet is discharged and cooled to obtain the intermediate rubber first stage mixed rubber.

[0216] S2, Two-stage mixing:

[0217] S2-1. The cooled cover rubber first-stage compound is put into an internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 200 seconds. When the rubber temperature in the internal mixer reaches 95°C, the bottom top bolt is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 260 seconds, then sheeted and cooled to obtain the cover rubber second-stage compound.

[0218] S2-2. The cooled intermediate rubber section 1 compound is put into the internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 200 seconds. When the rubber temperature in the internal mixer reaches 90°C, the bottom top bolt is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 260 seconds, then sheeted and cooled to obtain intermediate rubber section 2.

[0219] S3, composite, vulcanized:

[0220] A composite film is obtained by bonding an intermediate adhesive and a second-stage adhesive to both sides of an aramid skeleton, and then bonding a cover adhesive and a second-stage adhesive to the outside of the intermediate adhesive and the second-stage adhesive. The composite film is then vulcanized to obtain the final product.

[0221] In the vulcanization of the composite film, the vulcanization temperature is 155℃, the vulcanization pressure is 20MPa, and the vulcanization time is 35min.

[0222] Example 4

[0223] The flame-retardant aramid rope conveyor belt for underground coal mines, the cover rubber, and the proportion of raw materials used by weight are as follows:

[0224] 70 parts of styrene-butadiene rubber,

[0225] 4 parts butadiene rubber

[0226] 20 parts of rare earth butadiene rubber

[0227] 6 parts of epoxidized nitrile butadiene rubber,

[0228] Sulfur 3 parts,

[0229] Accelerator CZ 1.5 parts,

[0230] Accelerator DM 0.5 parts,

[0231] 3 parts zinc oxide

[0232] 2 parts stearic acid

[0233] Carbon black N220 40 parts

[0234] Si69 2 portions,

[0235] Anti-aging agent RD 0.8 parts,

[0236] Anti-aging agent 4010NA 0.8 parts,

[0237] 0.4 parts microcrystalline wax

[0238] 5 parts of flame retardant MCA

[0239] 20 parts of decabromodiphenyl ethane

[0240] 4 parts of antimony trioxide;

[0241] The proportions of raw materials used in the intermediate rubber, by weight, are as follows:

[0242] 64 parts of styrene-butadiene rubber,

[0243] 24 parts of butadiene rubber,

[0244] Adhesive d 12 parts,

[0245] 2.5 parts sulfur

[0246] Accelerator CZ 0.8 parts,

[0247] Accelerator DM 0.4 parts,

[0248] 3.6 parts zinc oxide

[0249] Stearic acid 2.4 parts,

[0250] Carbon black N220 35 parts

[0251] Si69 1.5 parts,

[0252] Anti-aging agent RD 0.75 parts,

[0253] Anti-aging agent 4010NA 0.5 parts,

[0254] 0.25 parts of microcrystalline wax

[0255] Flame retardant MCA 3.5 parts,

[0256] 10.5 parts of decabromodiphenyl ethane

[0257] Two parts of antimony trioxide.

[0258] Aramid rope pretreatment: The aramid rope was immersed in acetone for 2 hours, then dried at 60°C to remove the solvent, and irradiated with a 300W ultraviolet lamp for 8 minutes.

[0259] The preparation method of the flame-retardant aramid rope conveyor belt for underground coal mines includes the following steps:

[0260] S1, a stage of mixing:

[0261] S1-1. Styrene-butadiene rubber, butadiene rubber, rare earth butadiene rubber, and epoxidized nitrile rubber are added to a mixer and mixed for 50 seconds. Then, activator, antioxidant, flame retardant, and flame retardant synergist are added to the mixer and mixed for another 40 seconds. Then, dispersant and reinforcing agent are added and mixed for another 160 seconds. The top plug is raised and lowered. When the mixture in the mixer reaches 120°C, the bottom plug is opened and the mixed rubber is discharged to a sheeting machine for further mixing for 180 seconds. Then, the sheet is discharged, cooled, and the first stage of the cover rubber mixed rubber is obtained.

[0262] S1-2. Styrene-butadiene rubber and butadiene rubber are put into an internal mixer and mixed for 50 seconds. Then, activator, antioxidant, flame retardant and flame retardant synergist are added to the internal mixer and mixed for another 40 seconds. Then, dispersant, reinforcing agent and binder are added and mixed for another 120 seconds. The top plug is raised and lowered. When the mixture in the internal mixer reaches 115°C, the bottom plug is opened and the mixed rubber is discharged to the sheeting machine and mixed for another 180 seconds. Then, the sheet is discharged and cooled to obtain the intermediate rubber first stage mixed rubber.

[0263] S2, Two-stage mixing:

[0264] S2-1. The cooled cover rubber first-stage compound is put into an internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 120 seconds. When the rubber temperature in the internal mixer reaches 85°C, the bottom top bolt is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 180 seconds, then sheeted and cooled to obtain the cover rubber second-stage compound.

[0265] S2-2. The cooled intermediate rubber section 1 compound is put into the internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 120 seconds. When the rubber temperature in the internal mixer reaches 80°C, the bottom top bolt is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for another 180 seconds, then sheeted and cooled to obtain intermediate rubber section 2.

[0266] S3, composite, vulcanized:

[0267] The cover rubber and intermediate rubber were left to stand for 24 hours. The intermediate rubber was then bonded to both sides of the aramid skeleton, and the cover rubber was bonded to the outside of the intermediate rubber to obtain a composite film. The composite film was then vulcanized to obtain the final product.

[0268] In the vulcanization of the composite film, the vulcanization temperature is 145℃, the vulcanization pressure is 16MPa, and the vulcanization time is 25min.

[0269] Comparative Example 1

[0270] The difference between Comparative Example 1 and Example 4 is that the aramid rope was not pretreated by solvent impregnation and ultraviolet irradiation.

[0271] Comparative Example 2

[0272] The difference between Comparative Example 2 and Example 4 is that no adhesive d was added to the intermediate adhesive formulation.

[0273] Comparative Example 3

[0274] The difference between Comparative Example 3 and Example 4 is that step (1) is removed from the preparation method of adhesive d, that is, only γ-(methacryloyloxy)propyltrimethoxysilane is added to the intermediate adhesive as an adhesive, and the amount added is the same as the amount of γ-(methacryloyloxy)propyltrimethoxysilane used in the preparation method of adhesive d in Example 4.

[0275] Comparative Example 4

[0276] The difference between Comparative Example 4 and Example 4 is that epoxidized nitrile rubber was not added to the cover rubber formulation, and the formulation was adjusted to: 72 parts styrene-butadiene rubber, 9 parts butadiene rubber, and 19 parts rare earth butadiene rubber, with the rest being the same as in Example 1.

[0277] Performance testing

[0278] Film performance: The cover rubber and intermediate rubber from the examples and comparative examples were left to stand for 24 hours, then rolled into films using an open mill. The films were then cut according to the size of the vulcanizing mold, placed in the vulcanizing mold, and placed in a flat vulcanizing machine. The vulcanizing was carried out for 30 minutes under vulcanizing conditions of 18 MPa pressure and 150°C to obtain vulcanized test pieces. The performance was tested in accordance with MT / T914-2019 "Flame-retardant conveyor belts with fabric cores for coal mines". The results are shown in Table 1.

[0279] Table 1 Performance Test Table of Vulcanized Films in Examples and Comparative Examples

[0280]

[0281] Samples of conveyor belts from the examples and comparative examples were taken and tested in accordance with MT 668-2019 "Flame-retardant conveyor belts with steel wire rope core for coal mines". The results are shown in Table 2.

[0282] Table 2. Adhesion strength test results for examples and comparative examples.

[0283]

[0284] Compared with Comparative Example 1, Table 2 shows that the aramid rope in Comparative Example 1 was not pretreated, and its surface was smoother with relatively fewer active groups. Therefore, its bonding force with the intermediate adhesive was significantly reduced.

[0285] As shown in Table 1, Comparative Example 2 did not contain any self-made adhesive in its intermediate rubber formulation. The intermediate rubber lacked fluorine and silicone flame retardant elements and only had external flame retardants, resulting in a significant reduction in its flame retardancy. As shown in Table 2, the intermediate rubber lost its adhesive function, and the bonding force between the intermediate rubber and the cover rubber and aramid rope was significantly reduced, with the bonding force with the aramid rope being reduced even more significantly.

[0286] For Comparative Example 3, the data in Tables 1 and 2 show that the flame retardancy of the intermediate rubber was affected by the loss of fluorine. Furthermore, the intermediate rubber only relied on the coupling agent γ-(methacryloyloxy)propyltrimethoxysilane as an adhesive, which only has siloxane groups and double bonds, and did not introduce a block structure of bisphenol A and epoxy groups. Therefore, it could not achieve bonding with the interface of the cover rubber and the aramid through the epoxy groups, which led to a decrease in the bonding force of both interfaces.

[0287] For Comparative Example 4, the data in Table 2 show that the absence of epoxidized nitrile rubber reduces the bonding strength between the cover rubber and the intermediate rubber.

Claims

1. A flame-retardant aramid rope conveyor belt for underground coal mines, characterized in that, It includes an aramid skeleton made up of multiple aramid ropes and a cover adhesive covering the outside of the aramid skeleton. The aramid ropes that make up the aramid skeleton and the aramid skeleton and the cover adhesive are connected by an intermediate adhesive. The aramid rope is treated with solvent impregnation and ultraviolet light irradiation; The proportions of raw materials used in the cover adhesive by weight are as follows: 65-80 parts of styrene-butadiene rubber, 0-8 parts of butadiene rubber 15-20 parts of rare earth butadiene rubber 5-10 parts of epoxidized nitrile butadiene rubber, 2.5-4 parts vulcanizing agent, Accelerator 2-3 parts, 5-10 parts of surfactant 40-50 parts of reinforcing agent 2-3 parts dispersant Anti-aging agent 2-3.5 parts, 20-35 parts flame retardant 3-5 parts of flame retardant synergist; The proportions of raw materials used in the intermediate rubber, by weight, are as follows: 62-72 parts of styrene-butadiene rubber, 18-28 parts of butadiene rubber, 8-12 parts of adhesive, 2-3 parts of vulcanizing agent Accelerator 1-1.8 parts, Surfactant 6-8 parts, 35-40 parts of reinforcing agent Dispersant 1.5-2 parts, Anti-aging agent 1.5-2.5 parts, 12-14 parts flame retardant 1-2 parts of flame retardant synergist; The method for preparing the adhesive includes the following steps: (1) Mix a toluene solution of diallyl bisphenol A diglycidyl ether with hydrofluoric acid-terminated silicone oil, then add a platinum catalyst and heat the mixture to react. (2) Add γ-(methacryloyloxy)propyltrimethoxysilane, and remove toluene after the reaction to obtain the product; The molar ratio of diallyl bisphenol A diglycidyl ether to hydrofluorosilicone oil is less than 1, and the ratio of the sum of the molar numbers of diallyl bisphenol A diglycidyl ether and γ-(methacryloyloxy)propyltrimethoxysilane to the molar number of hydrofluorosilicone oil is greater than 1; the amount of platinum catalyst used is 0.18% of the mass of hydrofluorosilicone oil; in steps (1) and (2), the reaction temperature is 80-90℃ and the reaction time is 1.5-2.5h. The molecular formula of hydrofluoric silicone oil is as follows, where n is 10-20; 。 2. The flame-retardant aramid rope conveyor belt for underground coal mines according to claim 1, characterized in that, The aramid rope is made of strands of aramid filaments twisted together; the solvent is acetone, and the ultraviolet irradiation time is 5-8 minutes.

3. The flame-retardant aramid rope conveyor belt for underground coal mines according to claim 1, characterized in that, The vulcanizing agent is sulfur, the accelerator is a compound of accelerator CZ and accelerator DM with a mass ratio of (2-3):1, the activator is zinc oxide and stearic acid with a mass ratio of 3:2, the reinforcing agent is carbon black, the dispersant is silicon 69, and the antioxidants are antioxidant RD, antioxidant 4010NA and microcrystalline wax with a mass ratio of (1-1.5):(1-1.5):0.

5.

4. The flame-retardant aramid rope conveyor belt for underground coal mines according to claim 1, characterized in that, The flame retardant is MCA and decabromodiphenyl ethane in a mass ratio of 1:(3-5), and the flame retardant synergist is antimony trioxide.

5. A method for preparing a flame-retardant aramid rope conveyor belt for underground coal mines according to any one of claims 1-4, characterized in that, Includes the following steps: S1, a stage of mixing: S1-1. Styrene-butadiene rubber, butadiene rubber, rare earth butadiene rubber, and epoxidized nitrile rubber are added to a mixer and mixed for 50-90 seconds. Then, activators, antioxidants, flame retardants, and flame retardant synergists are added to the mixer and mixed for another 40-80 seconds. Then, dispersants and reinforcing agents are added and mixed for another 160-220 seconds. The top plug is raised and lowered. When the mixture in the mixer reaches 120-135°C, the bottom plug is opened and the mixed rubber is discharged to a sheeting machine for further mixing for 180-260 seconds. Then, the sheet is discharged, cooled, and the first stage of the cover rubber compound is obtained. S1-2. Styrene-butadiene rubber and butadiene rubber are put into an internal mixer and mixed for 50-90 seconds. Then, activator, antioxidant, flame retardant and flame retardant synergist are added to the internal mixer and mixed for another 40-80 seconds. Then, dispersant, reinforcing agent and binder are added and mixed for another 120-200 seconds. The top plug is raised and lowered. When the mixture in the internal mixer reaches 115-130°C, the bottom plug is opened and the mixed rubber is discharged to the sheeting machine for further mixing for 180-260 seconds. Then, the sheet is discharged and cooled to obtain the intermediate rubber first stage mixed rubber. S2, Two-stage mixing: S2-1. The cooled cover rubber first-stage compound is put into an internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 120-200 seconds. When the rubber temperature in the internal mixer reaches 85-95℃, the bottom top plug is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 180-260 seconds, then sheeted and cooled to obtain the cover rubber second-stage compound. S2-2. The cooled intermediate rubber section 1 compound is put into the internal mixer along with the vulcanizing agent and accelerator. The mixture is mixed for 120-200 seconds. When the rubber temperature in the internal mixer reaches 80-90℃, the bottom top plug is opened and the compound is discharged onto the sheeting machine. The mixture is then remixed for 180-260 seconds, then sheeted and cooled to obtain intermediate rubber section 2. S3, composite, vulcanized: A composite film is obtained by bonding an intermediate adhesive and a second-stage adhesive to both sides of an aramid skeleton, and then bonding a cover adhesive and a second-stage adhesive to the outside of the intermediate adhesive and the second-stage adhesive. The composite film is then vulcanized to obtain the final product.

6. The method for preparing a flame-retardant aramid rope conveyor belt for underground coal mines according to claim 5, characterized in that, In the vulcanization of composite films, the vulcanization temperature is 145-155℃, the vulcanization pressure is 16-20MPa, and the vulcanization time is 25-35min.

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