Fabric core flame-retardant conveyor belt rubber and plastic fiber flame-retardant covering rubber and preparation method thereof

Abstract

The application discloses a kind of fabric whole core flame-retardant conveying belt rubber and plastic fiber flame-retardant covering gum and preparation method thereof, including the following components: FR-PVG powder, polyvinyl chloride, chlorosulfonated polyethylene rubber, magnesium oxide, epoxy resin, accelerator DM, accelerator TRA, conductive carbon black, trimellitic acid trioctyl ester, flame retardant, epoxy soybean oil, ammonium polyphosphate melamine, antimony trioxide, calcium-zinc composite stabilizer, coupling agent, PE wax, 10wt% sulfuric acid solution, methacrylic acid, dicumyl peroxide;The application utilizes FR-PVG as matrix to prepare rubber and plastic fiber flame-retardant covering gum, avoids environmental pollution problem caused by processing FR-PVG, realizes green recycling and high-value utilization of FR-PVG, and innovates a new way of high-value and efficient green recycling and utilization of waste rubber and plastic fabric whole core flame-retardant conveying belt.

Description

Technical Field

[0001] This invention belongs to the field of waste polymer material recycling, and relates to the field of flame-retardant conveyor belt cover adhesive technology, specifically to a flame-retardant rubber and plastic fiber cover adhesive for fabric solid core conveyor belts and its preparation method. Background Technology

[0002] Flame-retardant conveyor belts made of solid woven rubber and plastic (FR-PVG) are a primary tool for transporting coal in underground mines in my country. The annual scrap volume reaches 400,000 tons. The basic components of waste FR-PVG conveyor belts are rubber, PVC (polyvinyl chloride), and polyester / cotton fibers. While the material properties remain largely unchanged during use and have high recycling value, they are difficult to recycle using traditional technologies, and can only be disposed of through landfill or incineration. This causes significant environmental problems and a huge waste of resources and energy. How to achieve green, efficient, high-value, and large-scale recycling of FR-PVG is a pressing and unresolved issue that requires immediate attention.

[0003] The powdered FR-PVG contains powdered rubber, PVC (polyvinyl chloride), and polyester-cotton fibers. Powdered rubber can effectively improve the performance of the resin. Partially cross-linked high-nitrile powdered nitrile rubber has good compatibility with PVC (polyvinyl chloride), high dispersibility, and improves the stability of the material. Rubber and PVC have a wide range of applications and the possibility of reusing them to produce flame-retardant conveyor belt cover rubber. Polyester-cotton fibers can improve the strength and wear resistance of the cover rubber, but when dispersed in rubber-plastic blends, they can easily affect the adhesive properties of the cover rubber, have a significant impact on the cross-linking and mixing of rubber and PVC, and are difficult to separate. FR-PVG also contains a large amount of inorganic flame retardants, such as magnesium hydroxide and aluminum hydroxide, which have poor compatibility with rubber-plastic blends. The flame retardants in the reprocessed cover rubber are prone to agglomeration, which has a significant impact on the flame retardant and mechanical properties of the cover rubber. Therefore, how to solve the problem of easy agglomeration of polyester fibers, cotton fibers, and flame retardants in FR-PVG powder is the key to the reuse of FR-PVG to prepare flame-retardant conveyor belt cover rubber.

[0004] Patent CN112679813A discloses a conveyor belt cover adhesive, its preparation method, and its application. By adding aliphatic hydrocarbon petroleum resin as a tackifier, it exhibits good distribution in polyvinyl chloride and nitrile rubber, forming a network structure. This improves the tensile strength, hardness, and elongation at break of the resulting conveyor belt cover adhesive, thereby enhancing its aging resistance and safety. However, this method cannot solve the problem of improving the dispersibility of polyester fibers, cotton fibers, and flame retardants.

[0005] Therefore, there is no fabric solid flame retardant conveyor belt rubber and plastic fiber flame retardant covering adhesive and its preparation method that can solve the problem of easy agglomeration of polyester and cotton fibers and flame retardants in FR-PVG, so that FR-PVG can be reused and realize the green recycling and high-value utilization of FR-PVG. Summary of the Invention

[0006] The purpose of this invention is to solve the problem of how to disperse polyester fibers, cotton fibers, and flame retardants in FR-PVG powder in the flame-retardant rubber and plastic fiber cover rubber of fabric solid flame-retardant conveyor belts, so as to prevent them from agglomerating and thus minimize their impact on the performance of the cover rubber. This allows the flame-retardant rubber and plastic fiber cover rubber of fabric solid flame-retardant conveyor belts prepared from waste to meet the performance requirements of rubber cover layers specified in MT / T914-2019, achieving green recycling and waste utilization.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A flame-retardant cover adhesive for solid woven fabric conveyor belts made of rubber and plastic fibers comprises the following components in parts by weight:

[0009] FR-PVG powder 50 parts, polyvinyl chloride 20-30 parts, chlorosulfonated polyethylene rubber 20-30 parts, magnesium oxide 1-3 parts, epoxy resin 1-3 parts, accelerator DM 0.6-1 parts, accelerator TRA 0.6-1 parts, conductive carbon black 12-16 parts, trioctyl trimellitate 12-16 parts, flame retardant 8-12 parts, epoxidized soybean oil 4-6 parts, ammonium polyphosphate melamine 6-8 parts, antimony trioxide 4-6 parts, calcium-zinc composite stabilizer 3-5 parts, coupling agent 3-5 parts, PE wax 1 part.

[0010] Furthermore, the FR-PVG powder is made by crushing waste rubber and plastic fabric solid flame-retardant conveyor belts, with a particle size of 60 mesh.

[0011] Furthermore, the coupling agent is any one of γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and titanate coupling agents;

[0012] Furthermore, the flame retardant is tris(β-chloroethyl) phosphate.

[0013] Furthermore, a flame-retardant rubber and plastic fiber cover adhesive for a solid woven flame-retardant conveyor belt also comprises the following components in parts by weight:

[0014] 120-150 parts of 10wt% sulfuric acid solution, 25-30 parts of methacrylic acid, and 0.2 parts of dicumyl peroxide.

[0015] Furthermore, a method for preparing a flame-retardant rubber and plastic fiber cover adhesive for a solid woven flame-retardant conveyor belt includes the following steps:

[0016] FR-PVG powder, ammonium melamine polyphosphate and antimony trioxide were put into a kneader and heated and stirred. A coupling agent was sprayed and the mixture was heated and stirred again to obtain a surface-modified FR-PVG blend.

[0017] The surface-modified FR-PVG blend was mixed with polyvinyl chloride, chlorosulfonated polyethylene rubber, conductive carbon black, trioctyl trimellitate, flame retardant, epoxidized soybean oil, calcium-zinc composite stabilizer and PE wax in an internal mixer to obtain a rubber-plastic fiber flame retardant cover rubber preplasticizer.

[0018] Furthermore, FR-PVG powder is prepared by the following steps: cleaning FR-PVG and cutting it into 200cm pieces. 2 The FR-PVG blocks of various sizes were crushed to obtain FR-PVG powder with a particle size of 60 mesh.

[0019] Furthermore, the stirring speed in the kneader is 340-350 rpm, the initial spraying temperature of the coupling agent is 40℃-50℃, and after the coupling agent is sprayed, heating and stirring continue until the temperature reaches 105℃-110℃, and stirring continues for 23-25 ​​minutes.

[0020] Furthermore, the internal mixer rotor speed is 40-50 rpm, the mixing temperature is 165℃-170℃, and the mixing time is 16-18 minutes. Then, magnesium oxide, epoxy resin, accelerator DM and accelerator TRA are added, and the mixing continues for 2-3 minutes.

[0021] Furthermore, the flame-retardant rubber and plastic fiber covering rubber of the fabric solid core flame-retardant conveyor belt is obtained by extruding the pre-plasticized rubber and plastic fiber flame-retardant covering rubber material through a twin-screw extrusion granulator and then dynamically vulcanizing the granules in the extruder.

[0022] The screw speed of the twin-cone screw extruder granulator is 30-40 rpm, and the temperature is 165℃-170℃.

[0023] The extruder has an L:D ratio of 28:1, and the temperature settings are as follows: Zone 1 140℃-150℃, Zone 2 150℃-160℃, Zone 3 160℃-170℃, and the die 160℃-170℃. The extruder screw speed is 30-40 rpm.

[0024] Furthermore, a method for preparing a flame-retardant rubber and plastic fiber cover adhesive for a solid woven flame-retardant conveyor belt includes the following steps:

[0025] FR-PVG powder was immersed in a 10wt% sulfuric acid solution, heated to 110-120℃, then methacrylic acid was added, ultrasonically vibrated for 20-30 min, heated to 130-140℃, pressurized to 0.5-1 MPa, and reacted for 1-1.5 h. The mixture was then filtered, washed with anhydrous ethanol and deionized water, and dried to obtain pretreated FR-PVG powder.

[0026] Pretreated FR-PVG powder, ammonium polyphosphate melamine, antimony trioxide and dicumyl peroxide are put into a kneader and heated and stirred at a speed of 340-350 rpm. The coupling agent is sprayed when the temperature is heated to 40℃-50℃. The heating and stirring are continued and stirred at 105℃-110℃ for 23-25 ​​minutes to obtain a surface-modified FR-PVG blend.

[0027] The surface-modified FR-PVG blends were mixed with polyvinyl chloride, chlorosulfonated polyethylene rubber, conductive carbon black, trioctyl trimellitate, flame retardant, epoxidized soybean oil, calcium-zinc composite stabilizer and PE wax in a mixer. The internal mixer rotor speed was 40-50 rpm, and the mixture was mixed at 165℃-170℃ for 16-18 minutes. Then, magnesium oxide, epoxy resin and accelerator were added, and the mixture was continued to be mixed for 2-3 minutes before discharge to obtain the rubber-plastic fiber flame retardant cover rubber preplasticized material.

[0028] The above pre-plasticized material is extruded and granulated through a twin-cone screw extrusion granulator at a screw speed of 30-40 rpm and a temperature of 165℃-170℃ to obtain flame-retardant rubber and plastic fiber covering granules.

[0029] The above granules are fed into an extruder with an L:D ratio of 28:1 for dynamic vulcanization and surface molding. The extruder and die are selected according to the conveyor belt specifications. The extruder temperature is set as follows: Zone 1 140℃-150℃, Zone 2 150℃-160℃, Zone 3 160℃-170℃, and die 160℃-170℃. The extruder screw speed is 30-40 rpm. The dynamically vulcanized rubber and plastic fiber flame retardant cover rubber is obtained through the extruder and die.

[0030] The beneficial effects of this invention are:

[0031] (1) Using waste rubber and plastic fabric solid flame retardant conveyor belt (FR-PVG) as the matrix to prepare rubber and plastic fiber flame retardant cover rubber for solid flame retardant conveyor belt, the environmental pollution problem caused by FR-PVG disposal is avoided, and the green recycling and high-value utilization of FR-PVG is realized. This innovates a new way for high-value, high-efficiency and green recycling of waste rubber and plastic fabric solid flame retardant conveyor belt.

[0032] (2) The prepared fabric solid core flame retardant conveyor belt rubber and plastic fiber flame retardant cover rubber has high strength, good wear resistance, and excellent flame retardant and antistatic properties. Its performance index is better than the performance of the rubber cover layer specified in MT / T914-2019. It has better mechanical properties and longer service life than the existing flame retardant cover rubber. It is low in cost and reusable, effectively solving the problems of poor mechanical properties, short service life and high production cost of the existing flame retardant cover rubber.

[0033] (3) This invention uses dilute sulfuric acid and methacrylic acid, which have no effect on the rubber properties, to pretreat FR-PVG powder, hydrolyzing cotton fibers into glucose. This solves the problem of the cotton fibers affecting the performance of the cover rubber colloid. Polyester fibers are linked by hydrogen bonds under the action of methacrylic acid, and glucose is further dehydrated and condensed, and is also linked with methacrylic acid by hydrogen bonds to form composite fibers. Methacrylic acid has good compatibility in nitrile rubber. Therefore, with the dispersing effect of methacrylic acid, the problem of easy agglomeration of polyester fibers in the cover rubber system is solved.

[0034] (4) Methacrylic acid can be synthesized with magnesium hydroxide to form magnesium methacrylate in the vulcanization system of nitrile rubber, which can be better dispersed in nitrile rubber, thereby making the composite fibers linked with methacrylic acid by hydrogen bonds more uniformly dispersed in nitrile rubber and reducing the agglomeration of polyester fibers in rubber; Nitrile rubber contains CN groups and has good compatibility with PVC. Therefore, by mixing nitrile rubber with PVC, magnesium methacrylate can be uniformly dispersed in PVC, which can not only improve the tensile properties of the cover rubber, but also reduce the influence of polyester fibers and magnesium hydroxide on the cover rubber; The flame retardant in FR-PVG powder, as well as ammonium melamine polyphosphate and antimony trioxide, are surface modified under the action of coupling agent, thereby mixing better with PVC and dispersing better in the cover rubber, achieving stronger flame retardant performance. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] The fabric solid-core flame-retardant conveyor belt rubber and plastic fiber flame-retardant covering adhesive of this embodiment contains the following components in parts by weight:

[0038] FR-PVG powder 50 parts, PVC (polyvinyl chloride) 30 parts, CSM (chlorosulfonated polyethylene rubber) 20 parts, MgO (magnesium oxide) 1 part, epoxy resin 1 part, accelerator DM 0.6 parts, accelerator TR A 0.6 parts, conductive carbon black 12 parts, TOTM (trioctyl trimellitate) 16 parts, TCEP (tris(β-chloroethyl) phosphate) 8 parts, ESO (epoxidized soybean oil) 4 parts, MPP (ammonium melamine polyphosphate) 8 parts, Sb2O 3( Antimony trioxide (4 parts), Ca-Zn (calcium-zinc composite stabilizer) (5 parts), NDZ (titanium ester coupling agent) (3 parts), PE wax (1 part);

[0039] FR-PVG powder is made by crushing waste rubber and plastic fabric solid flame-retardant conveyor belts, with a particle size of 60 mesh;

[0040] Polyvinyl chloride is PVC (SG-3);

[0041] The preparation method includes the following steps:

[0042] (1) Clean the FR-PVG thoroughly and cut it into 200cm pieces. 2 Block-shaped FR-PVG of various sizes;

[0043] (2) The blocky FR-PVG was crushed to obtain FR-PVG powder with a particle size of 60 mesh;

[0044] (3) FR-PVG powder, MPP and Sb2O3 were put into a kneader and heated and stirred at a stirring speed of 340 rpm. NDZ was sprayed when the temperature was raised to 40°C and the mixture was heated and stirred for 23 minutes at 105°C to obtain the surface-modified FV-PVG blend.

[0045] Coupling agents can modify the surface of FR-PVR / MPP / Sb2O3 blends, increasing their compatibility with PVC / CSM in the following steps, improving their dispersibility in flame-retardant cover rubber for rubber and plastic fibers, thereby improving the flame-retardant and mechanical properties of the flame-retardant cover rubber for rubber and plastic fibers.

[0046] (4) The surface-modified FV-PVG blends were mixed with PVC (SG-3), CSM, conductive carbon black, TOTM, TCEP, ESO, Ca-Zn and PE wax in a mixer. The rotor speed of the mixer was 40 rpm, and the mixture was mixed at 165°C for 16 minutes. Then MgO, epoxy resin, accelerator DM and accelerator TRA were added, and the mixture was continued to be mixed for 2 minutes before discharge to obtain the pre-plasticized rubber and plastic fiber flame retardant cover rubber.

[0047] The surface-modified FV-PVG blend has good compatibility with PVC. With the help of additives, the FV-PVG blend and conductive carbon black are evenly dispersed in the preplasticizer, which improves the flame retardancy and antistatic properties of the preplasticizer. The addition of magnesium oxide can improve the mechanical properties of the preplasticizer.

[0048] (5) The above preplasticized material is extruded and granulated through a double cone screw extrusion granulator at a screw speed of 30 rpm and a temperature of 165°C to obtain rubber and plastic fiber flame retardant covering granules.

[0049] (6) The above granules are put into an extruder with an L:D ratio of 28:1 for dynamic vulcanization and surface molding. The extruder and die are selected according to the specifications of the conveyor belt. The temperature settings of the extruder are as follows: Zone 1 140℃, Zone 2 150℃, Zone 3 160℃, Die 160℃, and the screw speed of the extruder is 30 rpm. The dynamically vulcanized rubber and plastic fiber flame retardant cover rubber is obtained through the extruder and die.

[0050] Example 2

[0051] The fabric solid-core flame-retardant conveyor belt rubber and plastic fiber flame-retardant covering adhesive of this embodiment contains the following components in parts by weight:

[0052] FR-PVG powder 50 parts, PVC (SG-3) 25 parts, CSM 25 parts, MgO 2 parts, epoxy resin 2 parts, accelerator DM 0.8 parts, accelerator TRA 0.8 parts, conductive carbon black 14 parts, TOTM 14 parts, TCEP 10 parts, ESO 5 parts, MPP 7 parts, Sb2O3 5 parts, Ca-Zn 4 parts, KH560 (γ-glycidyl etheroxypropyltrimethoxysilane) 4 parts, PE wax 1 part;

[0053] FR-PVG powder is made by crushing waste rubber and plastic fabric solid flame-retardant conveyor belts, with a particle size of 60 mesh;

[0054] The preparation method includes the following steps:

[0055] (1) Clean the FR-PVG thoroughly and cut it into 200cm pieces. 2 Block-shaped FR-PVG of various sizes;

[0056] (2) The blocky FR-PVG was crushed to obtain FR-PVG powder with a particle size of 60 mesh;

[0057] (3) FR-PVG powder, MPP and Sb2O3 are put into a kneader and heated and stirred at a stirring speed of 345 rpm. KH560 is sprayed when the temperature reaches 45°C. The mixture is heated and stirred for 24 minutes at 108°C to obtain a surface-modified FV-PVG blend.

[0058] (4) The surface-modified FV-PVG blends were mixed with PVC (SG-3), CSM, conductive carbon black, TOTM, TCEP, ESO, Ca-Zn and PE wax in a mixer. The rotor speed of the mixer was 45 rpm, and the mixture was mixed at 168°C for 17 minutes. Then MgO, epoxy resin, accelerator DM and accelerator TRA were added, and the mixture was continued to be mixed for 2.5 minutes before being discharged to obtain the pre-plasticized rubber and plastic fiber flame retardant covering rubber.

[0059] (5) The above preplasticized material is extruded and granulated through a double cone screw extrusion granulator at a screw speed of 35 rpm and a temperature of 168°C to obtain flame-retardant rubber and plastic fiber covering granules.

[0060] (6) The above granules are put into an extruder with an L:D ratio of 28:1 for dynamic vulcanization and surface molding. The extruder and die are selected according to the specifications of the conveyor belt. The temperature settings of the extruder are as follows: Zone 1 145℃, Zone 2 155℃, Zone 3 165℃, Die 165℃, and the screw speed of the extruder is 35 rpm. The dynamically vulcanized rubber and plastic fiber flame retardant cover rubber is obtained through the extruder and die.

[0061] Example 3

[0062] It contains the following components in parts by weight:

[0063] FR-PVG powder 50 parts, PVC (SG-3) 20 parts, CSM 30 parts, MgO 3 parts, epoxy resin 3 parts, accelerator DM 1 part, accelerator TRA 1 part, conductive carbon black 16 parts, TOTM 12 parts, TCEP 12 parts, ESO 4 parts, MPP 6 parts, Sb2O3 6 parts, Ca-Zn 3 parts, KH570 (γ-methacryloyloxypropyltrimethoxysilane) 5 parts, PE wax 1 part.

[0064] FR-PVG powder is made by crushing waste rubber and plastic fabric solid flame-retardant conveyor belts, with a particle size of 60 mesh;

[0065] The preparation method includes the following steps:

[0066] (1) Clean the FR-PVG thoroughly and cut it into 200cm pieces. 2 Block-shaped FR-PVG of various sizes;

[0067] (2) The blocky FR-PVG was crushed to obtain FR-PVG powder with a particle size of 60 mesh;

[0068] (3) FR-PVG powder, MPP and Sb2O3 are put into a kneader and heated and stirred at a stirring speed of 350 rpm. KH570 is sprayed when the temperature reaches 50°C. The mixture is heated and stirred for 25 minutes at 110°C to obtain a surface-modified FV-PVG blend.

[0069] (4) The surface-modified FV-PVG blends were mixed with PVC (SG-3), CSM, conductive carbon black, TOTM, TCEP, ESO, Ca-Zn and PE wax in a mixer. The rotor speed of the mixer was 50 rpm, and the mixture was mixed at 170°C for 18 minutes. Then MgO, epoxy resin, accelerator DM and accelerator TRA were added, and the mixture was continued to be mixed for 3 minutes before discharge to obtain the pre-plasticized rubber and plastic fiber flame retardant cover rubber.

[0070] (5) The above preplasticized material is extruded and granulated through a double cone screw extrusion granulator at a screw speed of 40 rpm and a temperature of 170°C to obtain flame-retardant rubber and plastic fiber covering granules.

[0071] (6) The above granules are put into an extruder with an L:D ratio of 28:1 for dynamic vulcanization and surface molding. The extruder and die are selected according to the specifications of the conveyor belt. The temperature settings of the extruder are as follows: Zone 1 150℃, Zone 2 160℃, Zone 3 170℃, Die 170℃, and the screw speed of the extruder is 40 rpm. The dynamically vulcanized rubber and plastic fiber flame retardant cover rubber is obtained through the extruder and die.

[0072] Example 4

[0073] FR-PVG powder 50 parts, PVC (SG-3) 30 parts, CSM 20 parts, MgO 1 part, epoxy resin 1 part, accelerator DM 0.6 parts, accelerator TRA 0.6 parts, conductive carbon black 12 parts, TOTM 16 parts, TCEP 8 parts, ESO 4 parts, MPP 8 parts, Sb2O3 4 parts, Ca-Zn 5 parts, NDZ 3 parts, PE wax 1 part.

[0074] 120 parts of 10wt% sulfuric acid solution, 25 parts of MAA (methacrylic acid), and 0.2 parts of dicumyl peroxide.

[0075] The preparation method includes the following steps:

[0076] (1) Clean the FR-PVG thoroughly and cut it into 200cm pieces. 2 Block-shaped FR-PVG of various sizes;

[0077] (2) The blocky FR-PVG was crushed to obtain FR-PVG powder with a particle size of 60 mesh;

[0078] (3) Immerse FR-PVG powder in 10wt% sulfuric acid solution, heat to 110℃, then add methacrylic acid, sonicate for 20min, heat to 130℃, pressurize to 0.5Mpa, react for 1h, then filter, wash with anhydrous ethanol and deionized water, dry and pulverize through a 60-mesh sieve to obtain pretreated FR-PVG powder.

[0079] FR-PVG powder contains cotton and polyester fibers. When dilute sulfuric acid is added at high temperature, the cotton fibers can be hydrolyzed into glucose. The terminal alcohol hydroxyl groups of the polyester fibers react with the carboxyl groups in the methacrylic acid molecules to form hydrogen bonds, thus connecting the polyester fibers with methacrylic acid. If the temperature is further increased, the glucose molecules will be isomerized, dehydrated, and undergo aldol condensation. They will then be connected to the polyester fibers and methacrylic acid through hydrogen bonds to obtain composite fibers.

[0080] (4) The pretreated FR-PVG powder, ammonium melamine polyphosphate, antimony trioxide and dicumyl peroxide were put into a kneader and heated and stirred at a stirring speed of 340 rpm. The coupling agent was sprayed when the temperature reached 40°C and the temperature was continued to be heated and stirred for 23 minutes at 105°C to obtain the surface-modified FV-PVG blend.

[0081] FR-PVG powder contains nitrile rubber and a large amount of flame retardants, including magnesium hydroxide and aluminum hydroxide. Methacrylic acid and magnesium hydroxide can synthesize magnesium methacrylate in nitrile rubber, which can improve the tensile strength of nitrile rubber. At the same time, under the action of coupling agent, the surface of magnesium hydroxide is modified, which improves the dispersibility of magnesium hydroxide.

[0082] (5) The surface-modified FV-PVG blends were mixed with polyvinyl chloride, chlorosulfonated polyethylene rubber, conductive carbon black, trioctyl trimellitate, flame retardant, epoxidized soybean oil, calcium-zinc composite stabilizer and PE wax in a mixer. The rotor speed of the mixer was 40 rpm, and the mixture was mixed at 165°C for 16 minutes. Then, magnesium oxide, epoxy resin and accelerator were added, and the mixture was continued to be mixed for 2 minutes before discharge to obtain the rubber-plastic fiber flame retardant cover rubber preplasticized material.

[0083] Because nitrile rubber contains CN groups, it is compatible with polyvinyl chloride (PVC) and can be uniformly dispersed in PVC. Therefore, magnesium methacrylate in nitrile rubber is also well dispersed. The composite fibers, which are linked to methacrylic acid by hydrogen bonds, are uniformly dispersed in the mixture of nitrile rubber and PVC under the action of magnesium methacrylate. Under the action of silane coupling agent, the flame retardant antimony trioxide and the intumescent flame retardant ammonium melamine polyphosphate are also compatible with PVC and have good dispersibility. The combined action of magnesium methacrylate, antimony trioxide, and ammonium melamine polyphosphate enhances the flame retardant properties of the material.

[0084] (6) The above preplasticized material is extruded and granulated through a double cone screw extrusion granulator at a screw speed of 30-40 rpm and a temperature of 165°C to obtain flame-retardant rubber and plastic fiber covering granules.

[0085] (7) The above granules are put into an extruder with an L:D of 28:1 for dynamic vulcanization and surface molding. The extruder and die are selected according to the specifications of the conveyor belt. The temperature settings of the extruder are as follows: Zone 1 140℃, Zone 2 150℃, Zone 3 160℃, Die 160℃, and the screw speed of the extruder is 30 rpm. The dynamically vulcanized rubber and plastic fiber flame retardant cover rubber is obtained through the extruder and die.

[0086] Example 5

[0087] FR-PVG powder 50 parts, PVC (SG-3) 20 parts, CSM 30 parts, MgO 3 parts, epoxy resin 3 parts, accelerator DM 1 part, accelerator TRA 1 part, conductive carbon black 16 parts, TOTM 12 parts, TCEP 12 parts, ESO 4 parts, MPP 6 parts, Sb2O3 6 parts, Ca-Zn 3 parts, KH57O 5 parts, PE wax 1 part.

[0088] 150 parts of 10wt% sulfuric acid solution, 30 parts of MAA, and 0.2 parts of dicumyl peroxide.

[0089] The preparation method includes the following steps:

[0090] (1) Clean the FR-PVG thoroughly and cut it into 200cm pieces. 2 Block-shaped FR-PVG of various sizes;

[0091] (2) The blocky FR-PVG was crushed to obtain FR-PVG powder with a particle size of 60 mesh;

[0092] (3) Immerse FR-PVG powder in 10wt% sulfuric acid solution, heat to 120℃, then add methacrylic acid, sonicate for 30 min, heat to 140℃, pressurize to 1 MPa, react for 1.5 h, then filter, wash with anhydrous ethanol and deionized water, dry and pulverize through a 60 mesh sieve to obtain pretreated FR-PVG powder.

[0093] (4) The pretreated FR-PVG powder, ammonium melamine polyphosphate, antimony trioxide and dicumyl peroxide were put into a kneader and heated and stirred at a stirring speed of 350 rpm. The coupling agent was sprayed when the temperature reached 50°C and the temperature was continued to be heated and stirred for 25 minutes at 110°C to obtain the surface-modified FV-PVG blend.

[0094] (5) The surface-modified FV-PVG blends were mixed with polyvinyl chloride, chlorosulfonated polyethylene rubber, conductive carbon black, trioctyl trimellitate, flame retardant, epoxidized soybean oil, calcium-zinc composite stabilizer and PE wax in a mixer. The rotor speed of the mixer was 50 rpm, and the mixture was mixed at 170°C for 18 minutes. Then magnesium oxide, epoxy resin and accelerator were added, and the mixture was continued to be mixed for 3 minutes before discharge to obtain the rubber-plastic fiber flame retardant cover rubber preplasticized material.

[0095] (6) The above preplasticized material is extruded and granulated through a double cone screw extrusion granulator at a screw speed of 40 rpm and a temperature of 170°C to obtain rubber and plastic fiber flame retardant covering granules.

[0096] (7) The above granules are put into an extruder with an L:D of 28:1 for dynamic vulcanization and surface molding. The extruder and die are selected according to the specifications of the conveyor belt. The temperature settings of the extruder are as follows: Zone 1 150℃, Zone 2 160℃, Zone 3 170℃, Die 170℃, and the screw speed of the extruder is 40 rpm. The dynamically vulcanized rubber and plastic fiber flame retardant cover rubber is obtained through the extruder and die.

[0097] The samples from implementations 1-5 were subjected to performance testing according to the provisions of MT / T914-2019, and the test data are shown in Table 1:

[0098] Table 1

[0099]

[0100]

[0101] As shown in Table 1, the performance of Examples 1-5 is superior to the requirements of MT / T914-2019. Among them, the performance of Examples 4-5 is superior to that of Examples 1-3. The data shows that the tensile strength and elongation at break of Examples 4-5 are improved compared to Examples 1-3, indicating that the addition of methacrylic acid improves the physical strength of nitrile rubber in FR-PVG. The wear and surface resistance decrease, indicating that the influence of polyester fiber and magnesium hydroxide on the cover rubber in the pretreated FR-PVG powder is reduced, improving the wear resistance of the cover rubber and the dispersion of conductive carbon black in the cover rubber, thus reducing the surface resistance. The average flame / no-flame time in the alcohol burner test is reduced, indicating that the cover rubber prepared in Examples 4-5 has better flame retardant performance, indicating that the flame retardant is more uniformly dispersed and has less agglomeration.

[0102] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A flame-retardant rubber and plastic fiber covering adhesive for a solid-core flame-retardant conveyor belt, characterized in that, It contains the following components by weight: FR-PVG powder 50 parts, polyvinyl chloride 20-30 parts, chlorosulfonated polyethylene rubber 20-30 parts, magnesium oxide 1-3 parts, epoxy resin 1-3 parts, accelerator DM 0.6-1 parts, accelerator TRA 0.6-1 parts, conductive carbon black 12-16 parts, trioctyl trimellitate 12-16 parts, tris(β-chloroethyl) phosphate 8-12 parts, epoxidized soybean oil 4-6 parts, ammonium polyphosphate melamine 6-8 parts, antimony trioxide 4-6 parts, calcium-zinc composite stabilizer 3-5 parts, coupling agent 3-5 parts, PE wax 1 part; It also contains the following components in parts by weight: 120-150 parts of 10wt% sulfuric acid solution, 25-30 parts of methacrylic acid, and 0.2 parts of dicumyl peroxide; The FR-PVG powder is made by crushing waste rubber and plastic fabric solid flame-retardant conveyor belt, with a particle size of 60 mesh. The coupling agent is any one of γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and titanate coupling agents; The preparation steps of the flame-retardant coating adhesive include: FR-PVG powder was immersed in a 10wt% sulfuric acid solution, heated to 110-120℃, then methacrylic acid was added, ultrasonically vibrated for 20-30 min, heated to 130-140℃, pressurized to 0.5-1 MPa, and reacted for 1-1.5 h. The mixture was then filtered, washed with anhydrous ethanol and deionized water, and dried to obtain pretreated FR-PVG powder. Pretreated FR-PVG powder, ammonium polyphosphate melamine, antimony trioxide and dicumyl peroxide are put into a kneader and heated and stirred at a speed of 340-350 rpm. The coupling agent is sprayed when the temperature is heated to 40℃-50℃. The heating and stirring are continued and stirred at 105℃-110℃ for 23-25 ​​minutes to obtain a surface-modified FR-PVG blend. The surface-modified FR-PVG blends were mixed with polyvinyl chloride, chlorosulfonated polyethylene rubber, conductive carbon black, trioctyl trimellitate, tris(β-chloroethyl) phosphate, epoxidized soybean oil, calcium-zinc composite stabilizer, and PE wax in a mixer. The mixer rotor speed was 40-50 rpm, and the mixture was mixed at 165℃-170℃ for 16-18 minutes. Then, magnesium oxide, epoxy resin, and accelerator were added, and the mixture was continued to be mixed for 2-3 minutes before discharge to obtain the pre-plasticized rubber-plastic fiber flame retardant cover rubber.

2. The flame-retardant rubber and plastic fiber covering adhesive for a solid-core flame-retardant conveyor belt according to claim 1, characterized in that, The FR-PVG powder is prepared by the following steps: cleaning the FR-PVG, cutting it into 200cm² blocks, crushing the blocks to obtain FR-PVG powder with a particle size of 60 mesh.

3. The flame-retardant rubber and plastic fiber covering adhesive for a solid-core flame-retardant conveyor belt according to claim 1, characterized in that, The flame-retardant rubber and plastic fiber cover rubber of the fabric solid core flame-retardant conveyor belt is obtained by extruding the pre-plasticized rubber and plastic fiber flame-retardant cover rubber material through a twin cone screw extrusion granulator and then dynamically vulcanizing the rubber and plastic fiber flame-retardant cover rubber granules in the extruder. The screw speed of the twin-cone screw extruder granulator is 30-40 rpm, and the temperature is 165℃-170℃. The extruder has an L:D ratio of 28:1, and the temperature settings are as follows: Zone 1 140℃-150℃, Zone 2 150℃-160℃, Zone 3 160℃-170℃, and the die 160℃-170℃. The extruder screw speed is 30-40 rpm.

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