Long-service-life, environment-friendly, flame-retardant and low-temperature-bending-resistant railway main air hose

Abstract

The invention discloses a long-service-life, environment-friendly, flame-retardant and low-temperature-bending-resistant railway main air hose which sequentially comprises an inner rubber layer and an outer rubber layer from inside to outside, the inner rubber layer and the outer rubber layer are provided with three reinforcing layers which are the first reinforcing layer, the second reinforcing layer and the third reinforcing layer from inside to outside in sequence, the first reinforcing layer and the third reinforcing layer are formed by weaving polyester threads, and the first reinforcing layer and the second reinforcing layer are formed by weaving polyester threads. The second reinforcing layer is a metal spiral layer formed by winding copper-plated steel wires; a first middle rubber layer is arranged between the first reinforcing frame layer and the second reinforcing layer, and a second middle rubber layer is arranged between the second reinforcing layer and the third reinforcing layer. The railway main air hose is better than an existing railway main air hose in environmental protection, flame retardance, ozone resistance, high temperature resistance and dynamic deflection pulse. The service life of the railway main air hose can reach 10 years.

Description

Technical Field

[0001] The present invention belongs to the field of rail transit and relates to a new type of long-life, environmentally friendly flame-retardant, and low-temperature bend-resistant main air hose for railways. Background Art

[0002] With the progress of national rail transit technology, the running speed of trains is continuously increasing, and the safety awareness is further enhanced. As one of the important systems of rail transit vehicles, the air source system provides dry and clean compressed air for the vehicle braking system and other on-vehicle pneumatic components. The main air pipe, as an important component in the air source system, is the main pipe that runs through the whole vehicle in the air supply system. It connects the air compressor and each main air cylinder, and sends the main air source to each vehicle for use by each air-using system including the braking system. Therefore, the main air hose plays an important role in the safe running of railway vehicles.

[0003] At present, the structure of the domestic railway main air hose is an inner rubber layer, a steel wire skeleton layer, and an outer rubber layer. Since the mechanical properties of steel wire and rubber are very different, the adhesion problem between steel wire and rubber has always been one of the main factors affecting the quality of the main air hose. During the actual use of the hose, under the action of hot air, oxygen, moisture, and other factors, the rubber-steel wire composite will undergo adhesion degradation, resulting in partial or complete delamination between the two, causing damage to the hose. At the same time, during the running of the train, the hose will be in a state of twisting, bending, or stretching, which is likely to cause deformation of the internal steel wire of the hose, thus affecting the service life of the hose. In addition, the outer rubber is generally non-flame-retardant rubber or halogen-containing flame-retardant rubber. In case of a fire, the hose is likely to produce toxic and harmful gases, causing secondary harm to users. Summary of the Invention

[0004] The purpose of the present invention is to provide a new type of long-life, environmentally friendly flame-retardant, and low-temperature bend-resistant main air hose for railways in view of the deficiencies of the prior art. The hose has very good low-temperature bendability, is environmentally friendly and flame-retardant, and resistant to high and low temperatures. The service life of the hose can reach 10 years.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A long-life, environmentally friendly flame-retardant, low-temperature bend-resistant railway main air hose. The railway main air hose successively includes an inner rubber layer and an outer rubber layer from inside to outside. There are 3 reinforcing layers between the inner rubber layer and the outer rubber layer, which are successively the first reinforcing layer, the second reinforcing layer, and the third reinforcing layer from inside to outside. The first reinforcing layer and the third reinforcing layer are woven from polyester yarns, and the second reinforcing layer is a metal spiral layer wound from copper-plated steel wires. There is a first middle rubber layer between the first reinforcing layer and the second reinforcing layer, and a second middle rubber layer between the second reinforcing layer and the third reinforcing layer. The rubber compound of the inner rubber layer is ethylene propylene diene monomer (EPDM) rubber compound with high and low temperature resistance and ozone resistance. The rubber compounds of the first middle rubber layer and the second middle rubber layer are the same, which is EPDM rubber compound with high and low temperature resistance and good adhesion to the skeleton material. The rubber compound of the outer rubber layer is EPDM rubber compound with environmental protection flame retardancy, ozone resistance and long life.

[0007] The EPDM rubber material of the inner rubber layer is made from the following raw materials in parts by weight: EPDM rubber: 100 parts, N550 carbon black: 80 - 100 parts, inorganic filler: 30 - 50 parts, paraffin oil: 20 - 30 parts, zinc oxide: 5 parts, stearic acid: 1 part, adhesive: 5 - 10 parts, sulfur: 1.0 - 2.0 parts, accelerator: 3.0 - 7.0 parts.

[0008] The inorganic filler is talcum powder.

[0009] The paraffin oil is paraffin oil 2280.

[0010] The adhesive is a combination of adhesive SL-3025C (i.e., bonding resin SL-3025C) and adhesive RA-65 in a weight ratio of 1:1.5.

[0011] The accelerator is one or more of zinc dibutyldithiocarbamate (BZ), N-cyclohexyl-2-benzothiazole sulfenamide (CZ), tetramethylthiuram disulfide (TMTD), and dibenzothiazole disulfide (DM). Preferably, the accelerator is a combination of accelerator BZ, accelerator CZ, accelerator TMTD, and accelerator DM in a weight ratio of 1:(1 - 1.5):(1.5 - 2):(1 - 2). Further preferably, the accelerator is a combination of accelerator BZ, accelerator CZ, accelerator TMTD, and accelerator DM in a weight ratio of 1:1:1.5:1.

[0012] The EPDM rubber material of the inner rubber layer is prepared by the following method, including:

[0013] Step (1), the internal mixer is cooled with water, the temperature of the internal mixer working chamber is controlled not to exceed 50°C, and EPDM rubber, zinc oxide, stearic acid, inorganic filler, and adhesive SL-3025C are added and kneaded for 45 - 60 seconds.

[0014] Step (2): Add paraffin oil and N550 carbon black, and knead for 3 - 5 minutes;

[0015] Step (3): Add sulfur, accelerator and binder RA - 65, knead, and discharge the rubber compound after the temperature reaches 120 °C;

[0016] Step (4): Transfer the rubber compound to a two - roll mill for thin - passing and sheet - making, and cool it to room temperature to obtain the ethylene - propylene - diene monomer (EPDM) rubber compound for the inner rubber layer.

[0017] The ethylene - propylene - diene monomer (EPDM) rubber materials for the first middle rubber layer and the second middle rubber layer are made from the following raw materials in parts by weight: ethylene - propylene - diene monomer: 100 parts, N550 carbon black: 40 - 60 parts, white carbon black: 10 - 20 parts, calcined clay: 30 - 50 parts, paraffin oil: 20 - 40 parts, zinc oxide: 5 parts, stearic acid: 1 part, coumarone resin: 5 - 10 parts, binder: 5 - 10 parts, sulfur: 2.0 - 3.0 parts, accelerator: 3.0 - 5.0 parts.

[0018] The paraffin oil is paraffin oil 2280.

[0019] The accelerator is one or more of N - cyclohexyl - 2 - benzothiazole sulfenamide (CZ), tetramethylthiuram disulfide (TMTD), dibenzothiazole disulfide (DM), and zinc dialkyldithiophosphate (ZAT); preferably, the accelerator is preferably a combination of accelerator CZ, accelerator TMTD, accelerator DM, and accelerator ZAT in a weight ratio of 1:(0.5 - 1):(1.5 - 2):(1 - 1.5); more preferably, the accelerator is a combination of accelerator CZ, accelerator TMTD, accelerator DM, and accelerator ZAT in a weight ratio of 1:0.5:1.5:1.

[0020] The binder is a combination of binder SL - 3025C and binder RA - 65 in a weight ratio of 1:1.5.

[0021] The ethylene - propylene - diene monomer (EPDM) rubber materials for the first and second middle rubber layers are prepared by the following method, including:

[0022] Step (1): Cool the internal mixer with water, control the temperature of the internal mixer working chamber not to exceed 50 °C, add ethylene - propylene - diene monomer, zinc oxide, stearic acid, white carbon black, calcined clay, coumarone resin, and binder SL - 3025C, and knead for 45 - 60 seconds;

[0023] Step (2): Add paraffin oil and N550 carbon black, and knead for 3 - 5 minutes;

[0024] Step (3): Add sulfur, accelerator and binder RA - 65, knead, and discharge the rubber compound after the temperature reaches 110 °C;

[0025] Step (4): Transfer the rubber compound to an open mill for thin-sheeting and cooling to room temperature to obtain the EPDM rubber material for the middle rubber layer.

[0026] The EPDM rubber material for the outer rubber layer is made from the following raw materials in parts by weight: EPDM rubber: 100 parts, active zinc oxide: 2 - 4 parts, stearic acid: 1 - 3 parts, N550 carbon black: 40 - 60 parts, calcium silicate: 40 - 60 parts, magnesium hydroxide: 10 - 20 parts, phosphorus-nitrogen based compound flame retardant: 70 - 90 parts, silane coupling agent A151: 2 - 5 parts, paraffin oil: 20 - 30 parts, adhesive: 5 - 10 parts, sulfur: 1 - 2 parts, comprehensive accelerator: 4 - 6 parts. The outer rubber layer is composed of flame-retardant EPDM rubber, endowing the main air hose of the present invention with excellent environmental protection flame-retardant performance and weather resistance.

[0027] The phosphorus-nitrogen based compound flame retardant is the phosphorus-nitrogen based compound flame retardant Longsafe 201.

[0028] The paraffin oil is paraffin oil 2280.

[0029] The comprehensive accelerator is comprehensive accelerator LHG-80, and comprehensive accelerator LHG-80 is a mixed comprehensive accelerator of dicyclohexylamine disulfide, dithiophosphate and basic accelerator.

[0030] The adhesive is a combination of adhesive SL-3025C and adhesive RA-65 in a weight ratio of 1:1.5.

[0031] The EPDM rubber material for the outer rubber layer is prepared by the following method, including:

[0032] Step (1): Cool the internal mixer with water, control the temperature of the internal mixer working chamber not exceeding 50°C, add EPDM rubber, active zinc oxide, stearic acid, calcium silicate, magnesium hydroxide, phosphorus-nitrogen based compound flame retardant, silane coupling agent A151 and adhesive SL-3025C, and knead for 80 - 100 seconds;

[0033] Step (2): Add paraffin oil and N550 carbon black, and knead for 3 - 5 minutes;

[0034] Step (3): Add sulfur, comprehensive accelerator and adhesive RA-65, knead, and discharge the rubber compound after the temperature reaches 120°C;

[0035] Step (4): Transfer the rubber compound to an open mill for thin-sheeting and cooling to room temperature to obtain the EPDM rubber material for the outer rubber layer.

[0036] Preferably, the adhesives used for the ethylene propylene diene monomer (EPDM) rubber material of the inner rubber layer, the EPDM rubber material of the first middle rubber layer, the EPDM rubber material of the second middle rubber layer, and the EPDM rubber material of the outer rubber layer are the same.

[0037] For the raw rubber selection of the inner layer rubber in the present invention, when considering the braiding tension of the reinforcing layer material during braiding acting on the inner layer rubber to prevent the phenomenon of rubber rolling; for the raw rubber selection of the middle layer rubber, it is considered to prevent cracking during the calendering process; for the raw rubber selection of the outer layer rubber, when considering filling with flame retardants, the dispersibility and physical properties of the filler are considered.

[0038] In the EPDM rubber material of the inner rubber layer, the Mooney viscosity ML(1+4) 125°C of the EPDM rubber is 60-70, and the ethylene content is 60-70%, specifically EPDM rubber 6470C; in the EPDM rubber materials of the first middle rubber layer and the second middle rubber layer, the Mooney viscosity ML(1+4) 125°C of the EPDM rubber is 75-85, and the ethylene content is 55-65%, specifically EPDM rubber SUPRENE S552; in the EPDM rubber material of the outer rubber layer, the Mooney viscosity ML(1+4) 125°C of the EPDM rubber is 75-85, and the ethylene content is 60-70%, specifically EPDM rubber 8570C.

[0039] The thickness of the inner rubber layer is 2.0-3.0 mm, the thickness of the first middle rubber layer is 0.3-0.5 mm, the thickness of the second middle rubber layer is 0.3-0.5 mm, and the thickness of the outer rubber layer is 0.8-1.5 mm.

[0040] The first reinforcing layer is woven from impregnated polyester yarns by a 24-spindle weaving method; the second reinforcing layer is wound from copper-plated steel wires by a 24-spindle winding method; the third reinforcing layer is woven from impregnated polyester yarns by a 24-spindle weaving method.

[0041] The specifications of the polyester yarns used for the first reinforcing layer and the third reinforcing layer are both 1500D-4000D; the diameter of the copper-plated steel wire is 0.30 mm.

[0042] The weaving coverage rate of the first reinforcing layer is 70%-80%; the winding coverage rate of the second reinforcing layer is 55%-65%; the weaving coverage rate of the third reinforcing layer is 70%-80%. The modulus of the copper-plated steel wire is higher than that of the polyester yarn. By reducing the coverage rate of the second reinforcing layer, the flexibility of the rubber hose can be improved. At the same time, copper plating on the steel wire can form a copper layer on the surface of the steel wire. Due to the strong adhesion performance of copper, the adhesion between the rubber and the steel wire can be effectively increased, reducing the occurrence of problems such as peeling, thereby improving the service life and safety of the rubber product.

[0043] The specifications of the railway main air hose include

[0044] Another object of the present invention is to provide a method for preparing the above-mentioned main reservoir hose for railways, comprising the following steps:

[0045] Step (1): Using a mandrel, extruding the inner rubber layer of the hose;

[0046] Step (2): Using impregnated polyester yarns, braiding on the outer side of the inner rubber layer to obtain a first reinforcing layer;

[0047] Step (3): Calendering out a first intermediate rubber layer to cover the first reinforcing layer;

[0048] Step (4): Using copper-plated steel wires, winding on the outer side of the first intermediate rubber layer to form a metal spiral layer, obtaining a second reinforcing layer;

[0049] Step (5): Calendering out a second intermediate rubber layer to cover the second reinforcing layer;

[0050] Step (6): Using impregnated polyester yarns, braiding on the outer side of the second intermediate rubber layer to obtain a third reinforcing layer;

[0051] Step (7): Extruding the outer rubber layer of the hose on the outer side of the third reinforcing layer;

[0052] Step (8): Vulcanizing the hose: vulcanizing and removing the mandrel to obtain the main reservoir hose for railways.

[0053] Advantages of the present invention:

[0054] The novel long-life, environmentally friendly flame-retardant, low-temperature bend-resistant main reservoir hose for railways of the present invention has the characteristics of long life, environmental protection and flame retardancy, and low-temperature flexural property. Specifically, it is shown as follows:

[0055] The adhesive SL-3025C selected in the present invention is an improved product of resorcinol, which solves the problems of high toxicity of resorcinol, uneven dispersion in the rubber compound, and easy blooming and adhesion decline. The adhesive SL-3025C can completely replace the resorcinol monomer in the resorcinol-formaldehyde-accelerator system, extend the scorch time of the rubber compound, improve the aging resistance of the rubber compound. At the same time, using the adhesive SL-3025C and RA-65 together can solve the problem of relatively poor adhesion between ethylene propylene diene monomer rubber and other materials, and improve the adhesion between the rubber compound before and after aging and the polyester fiber of the reinforcing layer.

[0056] The environmental protection flame retardancy, ozone resistance, high temperature resistance and dynamic flexing pulse of the main reservoir hose for railways of the present invention are superior to those of the existing ordinary main reservoir hoses for railways.

[0057] The main air hose of the railway in the present invention adopts a composite structure of two layers of polyester fiber braiding and one layer of metal wire winding as the skeleton. On the one hand, the fiber braiding layer can increase the impact resistance of the hose, protect the steel wire and the rubber compound from damage. Moreover, the metal spiral layer can withstand large tensile, compressive, bending and other forces. At the same time, it can also prevent the internal rubber layer from rupturing and prevent the collapse of the main air hose of the railway during the bending process, hindering the transportation of the working medium.

[0058] The service life of the main air hose of the railway in the present invention can reach 10 years. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a schematic structural diagram of the main air duct of the railway in the present invention.

[0060] Figure 1 In the figure, 1 - inner rubber layer, 2 - first reinforcing layer, 3 - first intermediate rubber layer, 4 - second reinforcing layer, 5 - second intermediate rubber layer, 6 - third reinforcing layer, 7 - outer rubber layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0061] The technical solution of the present invention will be further described below through specific embodiments.

[0062] As shown in Table 1, taking the main air hose of the railway with a certain specification as an example.

[0063] Table 1. Hose Structure

[0064]

[0065]

[0066] Embodiment 1

[0067] As Figure 1 shown in and Table 1, a new type of long - life, environmentally friendly flame - retardant, low - temperature bend - resistant main air hose of the railway includes, from the inside to the outside: an inner rubber layer 1, a first reinforcing layer 2, a first intermediate rubber layer 3, a second reinforcing layer 4, a second intermediate rubber layer 5, a third reinforcing layer 6, and an outer rubber layer 7.

[0068] The material of the inner rubber layer is made from the following raw materials in parts by weight: ethylene - propylene - diene monomer rubber 6470C: 100 parts, N550 carbon black: 90 parts, talcum powder: 40 parts, paraffin oil 2280: 25 parts, zinc oxide: 5 parts, stearic acid: 1 part, adhesive SL - 3025C: 3 parts, adhesive RA - 65: 4.5 parts, sulfur S: 1.5 parts, accelerator BZ: 1.0 part, accelerator CZ: 1.0 part, accelerator TMTD: 1.5 parts, accelerator DM: 1.0 part.

[0069] The material of the inner rubber layer is prepared by the following method:

[0070] Step (1): Cool the internal mixer with water, control the temperature of the internal mixer working chamber not to exceed 50°C, add ethylene propylene diene monomer rubber 6470C (base material), zinc oxide, stearic acid, talcum powder, and binder SL-3025C, and knead for 60 seconds;

[0071] Step (2): Add paraffin oil 2280 (plasticizer) and N550 carbon black, and knead for 5 minutes;

[0072] Step (3): Add sulfur S (vulcanizing agent), accelerator BZ, accelerator CZ, accelerator TMTD, accelerator DM, and binder RA-65, knead, and discharge the rubber compound after the temperature reaches 120°C;

[0073] Step (4): Transfer the rubber compound to an open mill for thin-sheeting and extruding, and cool it to room temperature to obtain the rubber compound for the inner rubber layer.

[0074] The materials of the first and second middle rubber layers are the same and are made from the following raw materials in parts by weight: ethylene propylene diene monomer rubber SUPRENE S552: 100 parts, N550 carbon black: 50 parts, white carbon black: 15 parts, calcined clay: 40 parts, paraffin oil 2280: 30 parts, zinc oxide: 5 parts, stearic acid: 1 part, coumarone resin: 8 parts, binder SL-3025C: 3 parts, binder RA-65: 4.5 parts, sulfur S: 2.5 parts, accelerator CZ: 1.0 part, accelerator TMTD: 0.5 part, accelerator DM: 1.5 parts, accelerator ZAT: 1.0 part.

[0075] The materials of the first and second middle rubber layers are prepared by the following method:

[0076] Step (1): Cool the internal mixer with water, control the temperature of the internal mixer working chamber not to exceed 50°C, add ethylene propylene diene monomer rubber SUPRENE S552 (base material), zinc oxide, stearic acid, white carbon black, calcined clay, coumarone resin, and binder SL-3025C, and knead for 60 seconds;

[0077] Step (2): Add paraffin oil 2280 and N550 carbon black, and knead for 5 minutes;

[0078] Step (3): Add sulfur (vulcanizing agent), accelerator CZ, accelerator TMTD, accelerator DM, accelerator ZAT, and binder RA-65, knead, and discharge the rubber compound after the temperature reaches 110°C;

[0079] Step (4): Transfer the rubber compound to an open mill for thin-sheeting and extruding, and cool it to room temperature to obtain the materials for the middle rubber layer.

[0080] The material of the outer rubber layer is made of raw materials in the following parts by weight: ethylene propylene diene monomer (EPDM) 8570C: 100 parts, active zinc oxide: 3 parts, stearic acid: 1.5 parts, N550 carbon black: 50 parts, calcium silicate: 50 parts, magnesium hydroxide: 15 parts, phosphorus-nitrogen compound flame retardant Longsafe 201: 80 parts, silane coupling agent A151: 3.5 parts, paraffin oil 2280: 25 parts, adhesive SL-3025C: 3.5 parts, adhesive RA-65: 5.25 parts, sulfur S: 1.5 parts, comprehensive accelerator LHG-80: 5 parts.

[0081] The material of the outer rubber layer is prepared by the following method:

[0082] Step (1): Cool the internal mixer with water, control the temperature of the internal mixer working chamber not to exceed 50 °C, add ethylene propylene diene monomer (EPDM) 8570C (base material), active zinc oxide, stearic acid, calcium silicate, magnesium hydroxide, phosphorus-nitrogen compound flame retardant, silane coupling agent A151 and adhesive SL-3025C, and knead for 90 seconds;

[0083] Step (2): Add paraffin oil 2280 (plasticizer) and N550 carbon black, and knead for 5 minutes;

[0084] Step (3): Add sulfur S (vulcanizing agent), comprehensive accelerator LHG-80 and adhesive RA-65, knead, and discharge the rubber compound after the temperature reaches 120 °C;

[0085] Step (4): Transfer the rubber compound to an open mill for thin-sheet extrusion, cool to room temperature, and obtain the material of the outer rubber layer.

[0086] The preparation method of the long-life, environmentally friendly flame-retardant and low-temperature bending-resistant main air hose for railways in this embodiment includes the following steps:

[0087] Step (1): Use a mandrel with an outer diameter of 22 mm to extrude the inner rubber layer of the rubber hose, and the thickness of the inner rubber layer is 2.5 mm;

[0088] Step (2): Use 3000D polyester yarn impregnated with glue, and weave it on the outside of the inner rubber layer according to the weaving method of 24 spindles and 3 strands per spindle to obtain the first reinforcement layer, and the weaving coverage rate of the first reinforcement layer is 70%;

[0089] Step (3): Calender out the first intermediate rubber layer to cover the first reinforcement layer, and the thickness of the rubber layer is 0.40 mm;

[0090] Step (4): Use copper-plated steel wires with a diameter of 0.30 mm to wind around the outside of the first intermediate rubber layer according to the winding method of 24 spindles and 2 strands per spindle to form a metal spiral layer, that is, obtain the second reinforcement layer, and the winding coverage rate of the second reinforcement layer is 60%;

[0091] Step (5): Calender out the second intermediate rubber layer to cover the second reinforcing layer, with the rubber layer thickness being 0.40 mm;

[0092] Step (6): Use 3000D polyester yarns impregnated with glue, and weave them in a 24-spindle and 4-strand-per-spindle weaving pattern on the outside of the second intermediate rubber layer to obtain the third reinforcing layer. The weaving coverage rate of the third reinforcing layer is 70%;

[0093] Step (7): Extrude the outer rubber layer of the rubber hose on the outside of the third reinforcing layer, with the rubber layer thickness being 1.0 mm;

[0094] Step (8): Vulcanize the rubber hose: Vulcanize at a temperature of 150 °C for 60 minutes; remove the core to obtain the main reservoir hose for railways.

[0095] Example 2

[0096] Compared with Example 1, for the novel long-life, environmentally friendly flame-retardant, and low-temperature bend-resistant main reservoir hose for railways in this example, the coverage rate of the first / third skeleton layer increases from 70% to 75%, and the others are the same as in Example 1. The main reservoir hose for railways is prepared according to the preparation method of Example 1.

[0097] Example 3

[0098] Compared with Example 1, for the novel long-life, environmentally friendly flame-retardant, and low-temperature bend-resistant main reservoir hose for railways in this example, the coverage rate of the first / third skeleton layer increases from 70% to 80%, and the others are the same as in Example 1. The main reservoir hose for railways is prepared according to the preparation method of Example 1.

[0099] Comparative Example 1

[0100] Compared with Example 1, Comparative Example 1 is an existing main reservoir hose for railways. The inner rubber layer is made of NBR rubber, the outer rubber layer is made of CR rubber, and there is only one reinforcing layer between the inner rubber layer and the outer rubber layer, and it is a steel wire braided structure.

[0101] Table 2. Hose Performance

[0102]

[0103]

[0104] Note: The adhesion strength between the reinforcement and the reinforcing layer refers to the adhesion strength between the first reinforcing layer and the second reinforcing layer, or the second reinforcing layer and the third reinforcing layer; specifically, it represents the adhesion strength between the fiber layer and the steel wire layer.

[0105] The performance results are shown in Table 2. Compared with the existing general railway main air hose (Comparative Example 1), the long-life, environmentally friendly flame-retardant, high and low temperature resistant railway main air hose of the present invention meets the performance requirements such as tensile, burst, and hydrostatic while the inner and outer rubbers of the hose are respectively replaced by ethylene propylene diene monomer rubber instead of nitrile rubber and chloroprene rubber, which not only meets the requirements of environmental protection and flame retardancy, but also improves the weather resistance and high and low temperature resistance of the hose; in addition, the second reinforcing layer with a winding structure also endows the hose with bending performance that the general railway main air hose does not have, improving the service life, which can reach 10 years.

Claims

1. A long-life, environmentally friendly flame-retardant and low-temperature bending-resistant main air hose for railways, characterized in that: The described railway main air hose successively includes an inner rubber layer and an outer rubber layer from the inside out. There are three reinforcing layers between the inner rubber layer and the outer rubber layer, which are the first reinforcing layer, the second reinforcing layer, and the third reinforcing layer successively from the inside out. The first reinforcing layer and the third reinforcing layer are woven from polyester threads, and the second reinforcing layer is a metal spiral layer wound from copper-plated steel wires; there is a first intermediate rubber layer between the first reinforcing layer and the second reinforcing layer, and a second intermediate rubber layer between the second reinforcing layer and the third reinforcing layer; the rubber compound of the inner rubber layer is ethylene propylene diene monomer (EPDM) rubber compound with resistance to high and low temperatures and ozone resistance; the rubber compounds of the first intermediate rubber layer and the second intermediate rubber layer are the same, which are EPDM rubber compounds with resistance to high and low temperatures and good adhesion to the skeleton material; the rubber compound of the outer rubber layer is an EPDM rubber compound with environmental protection, flame retardancy, ozone resistance, and long life.

2. The long-life, environmentally friendly flame-retardant and low-temperature bend-resistant main air hose for railways according to claim 1, characterized in that: The EPDM rubber material of the inner rubber layer is made of the following raw materials in parts by weight: EPDM rubber: 100 parts, N550 carbon black: 80 - 100 parts, inorganic filler: 30 - 50 parts, paraffin oil: 20 - 30 parts, zinc oxide: 5 parts, stearic acid: 1 part, binder: 5 - 10 parts, sulfur: 1.0 - 2.0 parts, accelerator: 3.0 - 7.0 parts; wherein, the inorganic filler is talcum powder; the accelerator is one or more of accelerator BZ, accelerator CZ, accelerator TMTD, and accelerator DM, preferably a combination with a weight ratio of accelerator BZ, accelerator CZ, accelerator TMTD, and accelerator DM of 1:(1 - 1.5):(1.5 - 2):(1 - 2), more preferably a combination with a weight ratio of accelerator BZ, accelerator CZ, accelerator TMTD, and accelerator DM of 1:1:1.5:

1.

3. The long-life, environmentally friendly flame-retardant and low-temperature bending-resistant main air hose for railways according to claim 1, characterized in that: The EPDM rubber materials of the first intermediate rubber layer and the second intermediate rubber layer are made of the following raw materials in parts by weight: EPDM rubber: 100 parts, N550 carbon black: 40 - 60 parts, white carbon black: 10 - 20 parts, calcined clay: 30 - 50 parts, paraffin oil: 20 - 40 parts, zinc oxide: 5 parts, stearic acid: 1 part, coumarone resin: 5 - 10 parts, binder: 5 - 10 parts, sulfur: 2.0 - 3.0 parts, accelerator: 3.0 - 5.0 parts; wherein, the accelerator is one or more of accelerator CZ, accelerator TMTD, accelerator DM, and accelerator ZAT, preferably a combination with a weight ratio of accelerator CZ, accelerator TMTD, accelerator DM, and accelerator ZAT of 1:(0.5 - 1):(1.5 - 2):(1 - 1.5), more preferably a combination with a weight ratio of accelerator CZ, accelerator TMTD, accelerator DM, and accelerator ZAT of 1:0.5:1.5:

1.

4. The long-life, environmentally friendly flame-retardant and low-temperature bending-resistant main air hose for railways according to claim 1, characterized in that: The ethylene propylene diene monomer (EPDM) rubber material of the outer rubber layer is made from the following raw materials in parts by weight: EPDM: 100 parts, active zinc oxide: 2 - 4 parts, stearic acid: 1 - 3 parts, N550 carbon black: 40 - 60 parts, calcium silicate: 40 - 60 parts, magnesium hydroxide: 10 - 20 parts, phosphorus-nitrogen compound flame retardant: 70 - 90 parts, silane coupling agent A151: 2 - 5 parts, paraffin oil: 20 - 30 parts, adhesive: 5 - 10 parts, sulfur: 1 - 2 parts, comprehensive accelerator: 4 - 6 parts; wherein, the phosphorus-nitrogen compound flame retardant is the phosphorus-nitrogen compound flame retardant Longsafe 201, and the comprehensive accelerator is the comprehensive accelerator LHG-80.

5. The long-life, environmentally friendly flame-retardant and low-temperature bending-resistant main air hose for railways according to claim 1, characterized in that: The adhesive of the EPDM rubber material of the inner rubber layer is a combination of adhesive SL-3025C and adhesive RA-65 in a weight ratio of 1:1.5; the adhesive of the EPDM rubber material of the first intermediate rubber layer and the second intermediate rubber layer is a combination of adhesive SL-3025C and adhesive RA-65 in a weight ratio of 1:1.5; the adhesive of the EPDM rubber material of the outer rubber layer is a combination of adhesive SL-3025C and adhesive RA-65 in a weight ratio of 1:1.

5.

6. The long-life, environmentally friendly flame-retardant and low-temperature bending-resistant main air hose for railways according to claim 1, characterized in that: In the EPDM rubber material of the inner rubber layer, the Mooney viscosity ML(1+4)125℃ of the EPDM is 60 - 70, and the ethylene content is 60 - 70%; in the EPDM rubber material of the first intermediate rubber layer and the second intermediate rubber layer, the Mooney viscosity ML(1+4)125℃ of the EPDM is 75 - 85, and the ethylene content is 55 - 65%; in the EPDM rubber material of the outer rubber layer, the Mooney viscosity ML(1+4)125℃ of the EPDM is 75 - 85, and the ethylene content is 60 - 70%.

7. The long-life, environmentally friendly flame-retardant and low-temperature bending-resistant main air hose for railways according to claim 1, characterized in that: The thickness of the inner rubber layer is 2.0 - 3.0 mm, the thickness of the first intermediate rubber layer is 0.3 - 0.5 mm, the thickness of the second intermediate rubber layer is 0.3 - 0.5 mm, and the thickness of the outer rubber layer is 0.8 - 1.5 mm.

8. The long-life, environmentally friendly flame-retardant and low-temperature bend-resistant main air hose for railways according to claim 1, characterized in that: The first reinforcing layer is woven from impregnated polyester yarns by a 24-spindle weaving method; the second reinforcing layer is wound from copper-plated steel wires by a 24-spindle winding method; the third reinforcing layer is woven from impregnated polyester yarns by a 24-spindle weaving method.

9. The long-life, environmentally friendly flame-retardant and low-temperature bending-resistant main air hose for railways according to claim 8, wherein: The specification of the polyester yarn is 1500D - 4000D; the diameter of the copper-plated steel wire is 0.30 mm.

10. The long-life, environmentally friendly flame-retardant and low-temperature bend-resistant main air hose for railways according to claim 8, characterized in that: The weaving coverage rate of the first reinforcing layer is 70% - 80%; the winding coverage rate of the second reinforcing layer is 55% - 65%; the weaving coverage rate of the third reinforcing layer is 70% - 80%.

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