Flame retardant EPDM rubber tube and preparation method thereof

Abstract

The invention discloses a flame-retardant EPDM rubber tube and a preparation method thereof. The flame-retardant EPDM rubber tube comprises the following components by mass fraction: 100-120 parts of EPDM rubber, 1-5 parts of zinc oxide, 70-90 parts of carbon black, 20-35 parts of paraffin oil, 0.5-3 parts of stearic acid, 1-3 parts of antioxidant, 1-10 parts of accelerator, 1-3 parts of vulcanizing agent and 20-30 parts of flame retardant. The flame retardant comprises the following components by mass fraction: 15-20 parts of styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, 10-15 parts of aluminum hydroxide, 2-3 parts of methylphenyl silicone resin and 5-10 parts of carbon forming agent. The present invention selects styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride through the selection of flame retardant components, which not only enhances the compatibility of the flame retardant in the material, but also ensures the mechanical properties of the material. Aluminum hydroxide and methylphenyl silicone resin are used as flame retardant components, which have a synergistic flame retardant effect and can reduce the influence on the mechanical properties of the rubber material. The copolymer grafted with maleic anhydride prevents the flame retardant components from being precipitated, thereby further ensuring the strength of the material.

Description

Technical Field

[0001] The invention relates to the technical field of rubber materials, and in particular to a flame retardant EPDM rubber tube and a preparation method thereof. Background Art

[0002] With the rapid development of industry, higher and higher requirements are put forward for the quality of rubber products. High speed, safety, comfort, energy saving and environmental protection are the goals pursued by contemporary automobile performance. At present, there are dozens of rubber types used for raw rubber hoses on the market, and the commonly used ones are natural rubber, styrene-butadiene rubber, EPDM rubber, chlorobutyl rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene and fluororubber. Among them, EPDM rubber is a rubber with good elasticity, wear resistance, heat resistance, weather resistance, ozone resistance and fresh water resistance. It is also a synthetic rubber with a wide source, so it is widely used in the preparation of rubber hoses.

[0003] In order to meet the safety requirements of EPDM rubber hose, EPDM rubber hose needs to have good flame retardant properties. At present, conventional flame retardant components use halogen flame retardant or aluminum hydroxide flame retardant. Although they have certain flame retardant properties, the increase of flame retardant components will affect the mechanical properties of the material. Therefore, how to improve the flame retardant properties of the material while ensuring the mechanical properties of the material is an urgent problem to be solved.

[0004] In view of this, this application is hereby filed.

[0005] In addition, the unreasonable combination of vulcanizers and accelerators in traditional EPDM rubber compounds can easily cause the rubber to produce acidic or alkaline substances, resulting in the decomposition of the polyester thread, the skeleton material of the hose, affecting the quality and life of the product. Summary of the invention

[0006] The technical problem to be solved by the present invention is that the existing conventional flame retardant components use halogen flame retardants or aluminum hydroxide flame retardants. Although they have certain flame retardant properties, the increase of flame retardant components will cause the mechanical properties of the material to be affected. The purpose is to provide a flame retardant EPDM rubber tube and a preparation method thereof. By selecting the ratio of the flame retardant components, not only the flame retardant properties of the rubber material can be improved, but also the mechanical properties of the material can be guaranteed.

[0007] The present invention is achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a flame retardant EPDM rubber tube, comprising the following components by mass fraction: 100-120 parts of EPDM rubber, 1-5 parts of zinc oxide, 70-90 parts of carbon black, 20-35 parts of paraffin oil, 0.5-3 parts of stearic acid, 1-3 parts of antioxidant, 1-10 parts of accelerator, and 1-3 parts of vulcanizer.

[0009] In a specific embodiment, a flame retardant EPDM rubber tube also includes 20 to 30 parts of a flame retardant, wherein the flame retardant includes styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, aluminum hydroxide, methylphenyl silicone resin and a carbon forming agent.

[0010] In a specific embodiment, the flame retardant includes the following components in parts by weight: 15 to 20 parts of styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, 10 to 15 parts of aluminum hydroxide, 2 to 3 parts of methylphenyl silicone resin and 5 to 10 parts of carbon forming agent.

[0011] The flame retardant of the present invention is a composition of styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, aluminum hydroxide, methylphenyl silicone resin and carbon forming agent. Firstly, by adding styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, the present invention can not only enhance the compatibility of the flame retardant in the whole material system and inhibit the precipitation of the flame retardant, but also improve the uniformity of the dispersion of auxiliary agents such as carbon forming agent and carbon black; in addition, the styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride is an elastomer, which can inhibit the growth of micro cracks caused by external stress and the pressure of water diffusion in the use environment, thereby avoiding cracking inside the rubber material and ensuring the mechanical properties of the material; wherein the styrene group of the styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride can also improve the dielectric strength of the material and enhance the insulation performance, and the hydrophilic group of the acid anhydride can generate a strong interaction with water molecules, which can make it difficult for water molecules in the environment to condense into droplets in the rubber, and play a significant water-resistant effect.

[0012] Secondly, the present invention selects a mixture of aluminum hydroxide and methylphenyl silicone resin as a flame retardant component, and the two have a synergistic flame retardant effect. Aluminum hydroxide does not contain halogen components and is environmentally friendly. Methylphenyl silicone resin is an organic silicon flame retardant, which cooperates with magnesium aluminum hydroxide to reduce the impact on the mechanical properties of the rubber material and achieve environmentally friendly flame retardancy. At the same time, styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride prevents the flame retardant component from precipitating in the rubber material, which can further ensure the strength of the rubber material.

[0013] Finally, by adding a carbon-forming agent and compounding it with the aforementioned flame-retardant components, the EPDM rubber can be effectively flame-retarded.

[0014] In a specific embodiment, the preparation method of the styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride is as follows: maleic anhydride is used as a grafting monomer and dicumyl peroxide is used as an initiator, and the mixture is blended with the styrene-ethylene / butylene-styrene block copolymer using a melt grafting method.

[0015] In a specific embodiment, the mass ratio of styrene-ethylene / butylene-styrene block copolymer, maleic anhydride and dicumyl peroxide is 70-80:1.5-2:0.1-0.12.

[0016] In a specific embodiment, the preparation method of the carbon-forming agent is as follows:

[0017] 1) mixing sodium montmorillonite and deionized water with mechanical stirring, heating in a water bath and stirring to obtain a montmorillonite suspension;

[0018] 2) Mix octadecyltrimethylammonium chloride and deionized water, and stir thoroughly until completely dissolved;

[0019] 3) The solution obtained in 2) is mixed with a montmorillonite suspension, heated and mechanically stirred, and the mixed suspension is then centrifuged and washed with deionized water, the white precipitate is ultrasonically vibrated, and dried and ground to obtain an OMMT particle carbonizing agent with an exfoliated lamellar structure.

[0020] The carbon forming agent of the flame retardant of the present invention is organic montmorillonite, which can not only enhance the flame retardant performance, but also improve the crystal structure of EPDM, fill the structure gaps, etc., so as to improve the strength of the material; at the same time, its layer peeling structure can weaken the destructive effect of the stress of the rubber material, ensure the mechanical properties of the rubber, and at the same time, after ultrasonic treatment, OMMT can be dispersed more evenly in the system, so that the filling effect of the flame retardant is more excellent, and precipitation in the rubber material is avoided.

[0021] In a specific embodiment, the antioxidant is antioxidant RD; the accelerator is a mixture of accelerator CZ and accelerator M; and the vulcanizing agent is sulfur S-80.

[0022] In a specific embodiment, the aluminum hydroxide is a mixture of aluminum hydroxide with a particle size of 18 to 20 μm and aluminum hydroxide with a particle size of 4 to 5 μm in a ratio of 2:1.

[0023] The aluminum hydroxide of the present invention adopts aluminum hydroxide with mixed particle sizes. The addition of aluminum hydroxide with a large particle size of 18 to 20 μm can improve the fluidity of the flame retardant and enhance the dispersion ability of the flame retardant. The aluminum hydroxide with a small particle size of 4 to 5 μm can significantly improve the problem of material deposition. At the same time, combined with the "binding" effect of the carbon-forming agent with an exfoliation layer structure on the aluminum hydroxide particles, the mechanical properties of the material can be guaranteed while the flame retardant performance is fully improved.

[0024] In a specific embodiment, the aluminum hydroxide is modified aluminum hydroxide; the modified aluminum hydroxide is modified using dodecyltrimethoxysilane; specifically: the aluminum hydroxide is stirred and dried at 60-80°C for 2h, a xylene solution of dodecyltrimethoxysilane with a concentration of 25-35% is added, the reaction is stirred at a temperature of 120-140°C for 0.5-1h, filtered and dried to obtain modified aluminum hydroxide; the mass ratio of the aluminum hydroxide to dodecyltrimethoxysilane is 100:1.5-2.5.

[0025] In the present invention, aluminum hydroxide is modified with dodecyltrimethoxysilane, which not only improves its dispersibility with the organic silicon flame retardant, but also improves its compatibility with the rubber material, thereby effectively ensuring the mechanical properties and flame retardant properties of the rubber material.

[0026] The second invention provides a method for preparing a flame retardant EPDM rubber tube, comprising the following steps:

[0027] (1) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 45-55°C, the speed is 32-35 rpm, and EPDM rubber is added and mixed for 1-3 minutes;

[0028] (2) Add zinc oxide, stearic acid and antioxidant and mix for 5 to 6 minutes;

[0029] (3) The internal mixer continues to pass cooling water, and carbon black, paraffin oil, and flame retardant are added to the internal mixer for mixing. When the temperature of the internal mixer reaches 140-150° C., the masterbatch is discharged and cooled to room temperature;

[0030] (4) Cooling water is passed through the internal mixer to control the working temperature of the internal mixer at 90-95°C, and the masterbatch is added. The mixture is mixed for 1-2 minutes, and the accelerator and the vulcanizer are added. When the temperature of the internal mixer reaches 105-110°C, the rubber is discharged to obtain the EPDM rubber compound.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] 1. A flame-retardant EPDM rubber tube and a preparation method thereof provided in an embodiment of the present invention can not only improve the flame retardant properties of the rubber material, but also ensure the mechanical properties of the material by selecting and proportioning the flame retardant components;

[0033] 2. A flame-retardant EPDM rubber tube and a preparation method thereof provided by an embodiment of the present invention can enhance the compatibility of the flame retardant in the entire material system and inhibit the precipitation of the flame retardant by adding styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, and can also improve the uniformity of dispersion of additives such as carbon forming agents and carbon black; in addition, the styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride is an elastomer, which can inhibit the growth of microcracks caused by external stress and the pressure of water diffusion in the use environment, thereby avoiding cracking inside the rubber material and ensuring the mechanical properties of the material;

[0034] 3. A flame-retardant EPDM rubber tube and a preparation method thereof provided in an embodiment of the present invention selects a mixture of aluminum hydroxide and methylphenyl silicone resin as a flame-retardant component, and the two have a synergistic flame-retardant effect. Aluminum hydroxide does not contain halogen components and is environmentally friendly. Methylphenyl silicone resin is an organic silicon flame retardant, which cooperates with magnesium aluminum hydroxide to reduce the impact on the mechanical properties of the rubber material and achieve environmentally friendly flame retardancy. At the same time, styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride prevents the flame-retardant component from precipitating in the rubber material, which can further ensure the strength of the rubber material.

[0035] 4. In the embodiment of the present invention, a flame retardant EPDM rubber tube and a preparation method thereof are provided. The carbon forming agent of the flame retardant is organic montmorillonite, which can not only enhance the flame retardant performance, but also improve the crystal structure of EPDM and fill the structural gaps, thereby improving the strength of the material; at the same time, its layer peeling structure can weaken the destructive effect of the stress of the rubber material and ensure the mechanical properties of the rubber. At the same time, after ultrasonic treatment, OMMT can be dispersed more evenly in the system, so that the filling effect of the flame retardant is more excellent and precipitation in the rubber material is avoided;

[0036] 5. A flame-retardant EPDM rubber tube and a preparation method thereof provided in an embodiment of the present invention, wherein aluminum hydroxide is aluminum hydroxide of mixed particle sizes, and the addition of aluminum hydroxide with a large particle size of 18 to 20 μm can improve the fluidity of the flame retardant and improve the dispersion ability of the flame retardant, and aluminum hydroxide with a small particle size of 4 to 5 μm can significantly improve the problem of material deposition, and at the same time, the "binding" effect of the carbon forming agent with a peeling layer structure on the aluminum hydroxide particles can fully improve the flame retardant performance while ensuring the mechanical properties of the material;

[0037] 6. An embodiment of the present invention provides a flame-retardant EPDM rubber tube and a preparation method thereof, wherein aluminum hydroxide is modified with dodecyltrimethoxysilane, which not only improves its dispersibility with silicone-based flame retardants, but also improves its compatibility with rubber materials, thereby effectively ensuring the mechanical properties and flame retardant properties of the rubber materials. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The illustrative embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0039] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to those of ordinary skill in the art that these specific details do not have to be employed to practice the present invention. In other embodiments, in order to avoid confusing the present invention, well-known methods are not specifically described.

[0040] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. Furthermore, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any appropriate combinations and / or subcombinations.

[0041] The invention comprises the following components by mass fraction: 100-120 parts of EPDM rubber, 1-5 parts of zinc oxide, 70-90 parts of carbon black, 20-35 parts of paraffin oil, 0.5-3 parts of stearic acid, 1-3 parts of antioxidant, 1-10 parts of accelerator and 1-3 parts of vulcanizing agent.

[0042] In a specific embodiment, a flame retardant EPDM rubber tube also includes 20 to 30 parts of a flame retardant, wherein the flame retardant includes styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, aluminum hydroxide, methylphenyl silicone resin and a carbon forming agent.

[0043] In a specific embodiment, the flame retardant includes the following components in parts by weight: 15 to 20 parts of styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, 10 to 15 parts of aluminum hydroxide, 2 to 3 parts of methylphenyl silicone resin and 5 to 10 parts of carbon forming agent.

[0044] The flame retardant of the present invention is a composition of styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, aluminum hydroxide, methylphenyl silicone resin and carbon forming agent. Firstly, by adding styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, the present invention can not only enhance the compatibility of the flame retardant in the whole material system and inhibit the precipitation of the flame retardant, but also improve the uniformity of the dispersion of auxiliary agents such as carbon forming agent and carbon black; in addition, the styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride is an elastomer, which can inhibit the growth of micro cracks caused by external stress and the pressure of water diffusion in the use environment, thereby avoiding cracking inside the rubber material and ensuring the mechanical properties of the material; wherein the styrene group of the styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride can also improve the dielectric strength of the material and enhance the insulation performance, and the hydrophilic group of the acid anhydride can generate a strong interaction with water molecules, which can make it difficult for water molecules in the environment to condense into droplets in the rubber, and play a significant water-resistant effect.

[0045] Secondly, the present invention selects a mixture of aluminum hydroxide and methylphenyl silicone resin as a flame retardant component, and the two have a synergistic flame retardant effect. Aluminum hydroxide does not contain halogen components and is environmentally friendly. Methylphenyl silicone resin is an organic silicon flame retardant, which cooperates with magnesium aluminum hydroxide to reduce the impact on the mechanical properties of the rubber material and achieve environmentally friendly flame retardancy. At the same time, styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride prevents the flame retardant component from precipitating in the rubber material, which can further ensure the strength of the rubber material.

[0046] Finally, by adding a carbon-forming agent and compounding it with the aforementioned flame-retardant components, the EPDM rubber can be effectively flame-retarded.

[0047] In a specific embodiment, the preparation method of the styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride is as follows: maleic anhydride is used as a grafting monomer and dicumyl peroxide is used as an initiator, and the mixture is blended with the styrene-ethylene / butylene-styrene block copolymer using a melt grafting method.

[0048] In a specific embodiment, the mass ratio of styrene-ethylene / butylene-styrene block copolymer, maleic anhydride and dicumyl peroxide is 70-80:1.5-2:0.1-0.12.

[0049] In a specific embodiment, the preparation method of the carbon-forming agent is as follows:

[0050] 1) mixing sodium montmorillonite and deionized water with mechanical stirring, heating in a water bath and stirring to obtain a montmorillonite suspension;

[0051] 2) Mix octadecyltrimethylammonium chloride and deionized water, and stir thoroughly until completely dissolved;

[0052] 3) The solution obtained in 2) is mixed with a montmorillonite suspension, heated and mechanically stirred, and the mixed suspension is then centrifuged and washed with deionized water, the white precipitate is ultrasonically vibrated, and dried and ground to obtain an OMMT particle carbonizing agent with an exfoliated lamellar structure.

[0053] The carbon forming agent of the flame retardant of the present invention is organic montmorillonite, which can not only enhance the flame retardant performance, but also improve the crystal structure of EPDM, fill the structure gaps, etc., so as to improve the strength of the material; at the same time, its layer peeling structure can weaken the destructive effect of the stress of the rubber material, ensure the mechanical properties of the rubber, and at the same time, after ultrasonic treatment, OMMT can be dispersed more evenly in the system, so that the filling effect of the flame retardant is more excellent, and precipitation in the rubber material is avoided.

[0054] In a specific embodiment, the antioxidant is antioxidant RD; the accelerator is a mixture of accelerator CZ and accelerator M; and the vulcanizing agent is sulfur S-80.

[0055] In a specific embodiment, the aluminum hydroxide is a mixture of aluminum hydroxide with a particle size of 18 to 20 μm and aluminum hydroxide with a particle size of 4 to 5 μm in a ratio of 2:1.

[0056] The aluminum hydroxide of the present invention adopts aluminum hydroxide with mixed particle sizes. The addition of aluminum hydroxide with a large particle size of 18 to 20 μm can improve the fluidity of the flame retardant and enhance the dispersion ability of the flame retardant. The aluminum hydroxide with a small particle size of 4 to 5 μm can significantly improve the problem of material deposition. At the same time, combined with the "binding" effect of the carbon-forming agent with an exfoliation layer structure on the aluminum hydroxide particles, the mechanical properties of the material can be guaranteed while the flame retardant performance is fully improved.

[0057] In a specific embodiment, the aluminum hydroxide is modified aluminum hydroxide; the modified aluminum hydroxide is modified using dodecyltrimethoxysilane; specifically: the aluminum hydroxide is stirred and dried at 60-80°C for 2h, a xylene solution of dodecyltrimethoxysilane with a concentration of 25-35% is added, the reaction is stirred at a temperature of 120-140°C for 0.5-1h, filtered and dried to obtain modified aluminum hydroxide; the mass ratio of the aluminum hydroxide to dodecyltrimethoxysilane is 100:1.5-2.5.

[0058] In the present invention, aluminum hydroxide is modified with dodecyltrimethoxysilane, which not only improves its dispersibility with the organic silicon flame retardant, but also improves its compatibility with the rubber material, thereby effectively ensuring the mechanical properties and flame retardant properties of the rubber material.

[0059] The second invention provides a method for preparing a flame retardant EPDM rubber tube, comprising the following steps:

[0060] (1) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 45-55°C, the speed is 32-35 rpm, and EPDM rubber is added and mixed for 1-3 minutes;

[0061] (2) Add zinc oxide, stearic acid and antioxidant and mix for 5 to 6 minutes;

[0062] (3) The internal mixer continues to pass cooling water, and carbon black, paraffin oil, and flame retardant are added to the internal mixer for mixing. When the temperature of the internal mixer reaches 140-150° C., the masterbatch is discharged and cooled to room temperature;

[0063] (4) Cooling water is passed through the internal mixer to control the working temperature of the internal mixer at 90-95°C, and the masterbatch is added. The mixture is mixed for 1-2 minutes, and the accelerator and the vulcanizer are added. When the temperature of the internal mixer reaches 105-110°C, the rubber is discharged to obtain the EPDM rubber compound.

[0064] Example 1

[0065] A method for preparing a flame retardant EPDM rubber tube provided in an embodiment of the present invention comprises the following steps:

[0066] (1) Preparation of modified aluminum hydroxide

[0067] Aluminum hydroxide with a particle size of 18 to 20 μm and 4 to 5 μm is stirred and dried at 60 to 80° C. for 2 hours, a xylene solution of dodecyltrimethoxysilane with a concentration of 25 to 35% is added, and the mixture is stirred and reacted at a temperature of 120 to 140° C. for 0.5 to 1 hour, filtered and dried to obtain modified aluminum hydroxide; the mass ratio of the aluminum hydroxide to dodecyltrimethoxysilane is 100:1.5 to 2.5;

[0068] (2) Preparation of carbon agent

[0069] 1) mixing sodium montmorillonite and deionized water with mechanical stirring, heating in a water bath and stirring to obtain a montmorillonite suspension;

[0070] 2) Mix octadecyltrimethylammonium chloride and deionized water, and stir thoroughly until completely dissolved;

[0071] 3) The solution obtained in 2) is mixed with a montmorillonite suspension, heated and mechanically stirred, and the mixed suspension is then centrifuged and washed with deionized water, the white precipitate is ultrasonically vibrated, and dried and ground to obtain an OMMT particle carbonizing agent with an exfoliated lamellar structure.

[0072] (3) Preparation of Styrene-Ethylene / Butylene-Styrene Block Copolymer Grafted with Maleic Anhydride

[0073] 1) placing maleic anhydride (MAH), dicumyl peroxide (DCP) and SEBS in a drying oven for drying;

[0074] 2) 80 parts of SEBS, 2 parts of MAH and 0.12 parts of DCP were added into a high-speed mixer for blending;

[0075] 3) putting the blended raw materials into a twin-screw extruder for melt blending, the temperature of each zone of the twin-screw extruder is 170-185°C, the neck temperature is 185-195°C, the head temperature is 195-205°C; the main engine speed is 25-50r / min;

[0076] 4) pulling the extrudate through water for cooling, and pelletizing it in a pelletizer to obtain styrene-ethylene / butylene-styrene block copolymer grafted maleic anhydride particles;

[0077] (4) Preparation of flame retardant

[0078] Styrene-ethylene / butylene-styrene block copolymer is grafted with 15 parts of maleic anhydride, 10 parts of aluminum hydroxide, 2 parts of methylphenyl silicone resin and 5 parts of carbon forming agent, and the mixture is mixed, extruded and granulated to prepare flame retardant particles;

[0079] (5) Preparation of flame-retardant EPDM rubber tube

[0080] 1) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 45-55°C, the speed is 32-35rpm, and EPDM rubber is added and mixed for 1-3min;

[0081] 2) Add zinc oxide, stearic acid and antioxidant and mix for 5 to 6 minutes;

[0082] 3) Continue to pass cooling water through the internal mixer, add carbon black, paraffin oil and flame retardant into the internal mixer for mixing, and when the temperature of the internal mixer reaches 140-150°C, discharge the masterbatch and cool it to room temperature;

[0083] 4) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 90-95°C, masterbatch is added, and internal mixing is performed for 1-2 minutes, and accelerator and vulcanizing agent are added. When the temperature of the internal mixer reaches 105-110°C, the rubber is discharged to obtain EPDM rubber compound;

[0084] Among them, 100 parts of EPDM rubber, 1 part of zinc oxide, 70 parts of carbon black, 20 parts of paraffin oil, 0.5 parts of stearic acid, 1 part of antioxidant, 1 part of accelerator, 1 part of vulcanizing agent, and 20 parts of flame retardant.

[0085] Example 2

[0086] A method for preparing a flame retardant EPDM rubber tube provided in an embodiment of the present invention comprises the following steps:

[0087] (1) Preparation of modified aluminum hydroxide

[0088] Aluminum hydroxide with a particle size of 18 to 20 μm and 4 to 5 μm is stirred and dried at 60 to 80° C. for 2 hours, a xylene solution of dodecyltrimethoxysilane with a concentration of 25 to 35% is added, and the mixture is stirred and reacted at a temperature of 120 to 140° C. for 0.5 to 1 hour, filtered and dried to obtain modified aluminum hydroxide; the mass ratio of the aluminum hydroxide to dodecyltrimethoxysilane is 100:1.5 to 2.5;

[0089] (2) Preparation of carbon agent

[0090] 1) mixing sodium montmorillonite and deionized water with mechanical stirring, heating in a water bath and stirring to obtain a montmorillonite suspension;

[0091] 2) Mix octadecyltrimethylammonium chloride and deionized water, and stir thoroughly until completely dissolved;

[0092] 3) The solution obtained in 2) is mixed with a montmorillonite suspension, heated and mechanically stirred, and the mixed suspension is then centrifuged and washed with deionized water, the white precipitate is ultrasonically vibrated, and dried and ground to obtain an OMMT particle carbonizing agent with an exfoliated lamellar structure.

[0093] (3) Preparation of Styrene-Ethylene / Butylene-Styrene Block Copolymer Grafted with Maleic Anhydride

[0094] 1) placing maleic anhydride (MAH), dicumyl peroxide (DCP) and SEBS in a drying oven for drying;

[0095] 2) 80 parts of SEBS, 2 parts of MAH and 0.12 parts of DCP were added into a high-speed mixer for blending;

[0096] 3) putting the blended raw materials into a twin-screw extruder for melt blending, the temperature of each zone of the twin-screw extruder is 170-185°C, the neck temperature is 185-195°C, the head temperature is 195-205°C; the main engine speed is 25-50r / min;

[0097] 4) pulling the extrudate through water for cooling, and pelletizing it in a pelletizer to obtain styrene-ethylene / butylene-styrene block copolymer grafted maleic anhydride particles;

[0098] (4) Preparation of flame retardant

[0099] Styrene-ethylene / butylene-styrene block copolymer is grafted with 20 parts of maleic anhydride, 15 parts of aluminum hydroxide, 3 parts of methylphenyl silicone resin and 10 parts of carbon forming agent, and the mixture is mixed, extruded and granulated to prepare flame retardant particles;

[0100] (5) Preparation of flame-retardant EPDM rubber tube

[0101] 1) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 45-55°C, the speed is 32-35rpm, and EPDM rubber is added and mixed for 1-3min;

[0102] 2) Add zinc oxide, stearic acid and antioxidant and mix for 5 to 6 minutes;

[0103] 3) Continue to pass cooling water through the internal mixer, add carbon black, paraffin oil and flame retardant into the internal mixer for mixing, and when the temperature of the internal mixer reaches 140-150°C, discharge the masterbatch and cool it to room temperature;

[0104] 4) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 90-95°C, masterbatch is added, and internal mixing is performed for 1-2 minutes, and accelerator and vulcanizing agent are added. When the temperature of the internal mixer reaches 105-110°C, the rubber is discharged to obtain EPDM rubber compound;

[0105] Among them, 120 parts of EPDM rubber, 5 parts of zinc oxide, 90 parts of carbon black, 35 parts of paraffin oil, 3 parts of stearic acid, 3 parts of antioxidant, 10 parts of accelerator, 3 parts of vulcanizer, and 30 parts of flame retardant.

[0106] Example 3

[0107] A method for preparing a flame retardant EPDM rubber tube provided in an embodiment of the present invention comprises the following steps:

[0108] (1) Preparation of modified aluminum hydroxide

[0109] Aluminum hydroxide with a particle size of 18 to 20 μm and 4 to 5 μm is stirred and dried at 60 to 80° C. for 2 hours, a xylene solution of dodecyltrimethoxysilane with a concentration of 25 to 35% is added, and the mixture is stirred and reacted at a temperature of 120 to 140° C. for 0.5 to 1 hour, filtered and dried to obtain modified aluminum hydroxide; the mass ratio of the aluminum hydroxide to dodecyltrimethoxysilane is 100:1.5 to 2.5;

[0110] (2) Preparation of carbon agent

[0111] 1) mixing sodium montmorillonite and deionized water with mechanical stirring, heating in a water bath and stirring to obtain a montmorillonite suspension;

[0112] 2) Mix octadecyltrimethylammonium chloride and deionized water, and stir thoroughly until completely dissolved;

[0113] 3) The solution obtained in 2) is mixed with a montmorillonite suspension, heated and mechanically stirred, and the mixed suspension is then centrifuged and washed with deionized water, the white precipitate is ultrasonically vibrated, and dried and ground to obtain an OMMT particle carbonizing agent with an exfoliated lamellar structure.

[0114] (3) Preparation of Styrene-Ethylene / Butylene-Styrene Block Copolymer Grafted with Maleic Anhydride

[0115] 1) placing maleic anhydride (MAH), dicumyl peroxide (DCP) and SEBS in a drying oven for drying;

[0116] 2) 80 parts of SEBS, 2 parts of MAH and 0.12 parts of DCP were added into a high-speed mixer for blending;

[0117] 3) putting the blended raw materials into a twin-screw extruder for melt blending, the temperature of each zone of the twin-screw extruder is 170-185°C, the neck temperature is 185-195°C, the head temperature is 195-205°C; the main engine speed is 25-50r / min;

[0118] 4) pulling the extrudate through water for cooling, and pelletizing it in a pelletizer to obtain styrene-ethylene / butylene-styrene block copolymer grafted maleic anhydride particles;

[0119] (4) Preparation of flame retardant

[0120] Styrene-ethylene / butylene-styrene block copolymer is grafted with 18 parts of maleic anhydride, 13 parts of aluminum hydroxide, 3 parts of methylphenyl silicone resin and 8 parts of carbon forming agent, and the mixture is mixed, extruded and granulated to prepare flame retardant particles;

[0121] (5) Preparation of flame-retardant EPDM rubber tube

[0122] 1) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 45-55°C, the speed is 32-35rpm, and EPDM rubber is added and mixed for 1-3min;

[0123] 2) Add zinc oxide, stearic acid and antioxidant and mix for 5 to 6 minutes;

[0124] 3) Continue to pass cooling water through the internal mixer, add carbon black, paraffin oil and flame retardant into the internal mixer for mixing, and when the temperature of the internal mixer reaches 140-150°C, discharge the masterbatch and cool it to room temperature;

[0125] 4) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 90-95°C, masterbatch is added, and internal mixing is performed for 1-2 minutes, and accelerator and vulcanizing agent are added. When the temperature of the internal mixer reaches 105-110°C, the rubber is discharged to obtain EPDM rubber compound;

[0126] Among them, 110 parts of EPDM rubber, 3 parts of zinc oxide, 80 parts of carbon black, 30 parts of paraffin oil, 2 parts of stearic acid, 2 parts of antioxidant, 6 parts of accelerator, 2 parts of vulcanizer, and 25 parts of flame retardant.

[0127] Comparative Example 1

[0128] The method for preparing an EPDM rubber tube provided in this comparative example is different from that in Example 3 in that no flame retardant is included.

[0129] Comparative Example 2

[0130] The method for preparing an EPDM rubber tube provided in this comparative example is different from that in Example 3 in that the flame retardant is 25 parts of aluminum hydroxide.

[0131] Comparative Example 3

[0132] The method for preparing an EPDM rubber tube provided in this comparative example is different from that in Example 3 in that the flame retardant does not contain styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride.

[0133] Comparative Example 4

[0134] The method for preparing an EPDM rubber tube provided in this comparative example is different from that in Example 3 in that the flame retardant does not contain methyl phenyl silicone resin.

[0135] Comparative Example 5

[0136] The method for preparing an EPDM rubber tube provided in this comparative example is different from that in Example 3 in that the flame retardant does not contain a carbon-forming agent.

[0137] Performance Testing

[0138] Corresponding performance tests were performed on the rubber materials obtained in Examples 1-3 and Comparative Examples 1-5. The test results are shown in Table 1.

[0139] Table 1

[0140]

[0141]

[0142] It can be seen from Table 1 that the flame retardant components in Examples 1-3 of the present invention can not only improve the flame retardant properties of the rubber material, but also ensure the mechanical properties of the material.

[0143] Compared with comparative example 1, comparative example 1 does not add flame retardant, and it can be seen that the flame retardant performance of embodiment 3 is significantly lower than that of embodiment 3. After adding flame retardant, embodiment 3 not only has good flame retardancy, but also has correspondingly improved mechanical properties.

[0144] Compared with Example 2, Example 3 has a flame retardant of a single component aluminum hydroxide, and although the flame retardant performance is improved to a certain extent, the mechanical properties are reduced accordingly.

[0145] Compared with Comparative Example 3, the flame retardant of Comparative Example 3 does not contain styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride. Therefore, although its flame retardant performance is greatly improved, its mechanical properties are significantly lower than those of Example 3.

[0146] Compared with Example 4, Example 3 does not contain methylphenyl silicone resin in the flame retardant of Comparative Example 4. Although its flame retardant performance is not affected, its mechanical properties are still slightly reduced.

[0147] Compared with Example 5, Example 3 does not contain a carbon-forming agent in the flame retardant of Comparative Example 5, and its flame retardant performance is slightly worse than that of Example 3, and its mechanical properties are also reduced.

[0148] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flame retardant EPDM rubber tube, characterized in that: The invention comprises the following components by mass fraction: 100-120 parts of EPDM rubber, 1-5 parts of zinc oxide, 70-90 parts of carbon black, 20-35 parts of paraffin oil, 0.5-3 parts of stearic acid, 1-3 parts of antioxidant, 1-10 parts of accelerator and 1-3 parts of vulcanizing agent.

2. The flame retardant EPDM rubber tube according to claim 1, characterized in that: The invention also comprises 20 to 30 parts of a flame retardant, wherein the flame retardant comprises styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, aluminum hydroxide, methylphenyl silicone resin and a carbon forming agent.

3. The flame retardant EPDM rubber tube according to claim 2, characterized in that: The flame retardant comprises the following components in parts by weight: 15 to 20 parts of styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride, 10 to 15 parts of aluminum hydroxide, 2 to 3 parts of methylphenyl silicone resin and 5 to 10 parts of a carbon forming agent.

4. The flame retardant EPDM rubber tube according to claim 1, characterized in that: The preparation method of the styrene-ethylene / butylene-styrene block copolymer grafted with maleic anhydride is as follows: maleic anhydride is used as a grafting monomer, dicumyl peroxide is used as an initiator, and the mixture is blended with the styrene-ethylene / butylene-styrene block copolymer by a melt grafting method.

5. The flame retardant EPDM rubber tube according to claim 4, characterized in that: The mass ratio of styrene-ethylene / butylene-styrene block copolymer, maleic anhydride and dicumyl peroxide is 70-80:1.5-2:0.1-0.

12.

6. The flame retardant EPDM rubber tube according to claim 1, characterized in that: The preparation method of the carbon forming agent is as follows: 1) mixing sodium montmorillonite and deionized water, mechanically stirring, heating in a water bath and stirring to obtain a montmorillonite suspension; 2) Mix octadecyltrimethylammonium chloride and deionized water, and stir thoroughly until completely dissolved; 3) The solution obtained in 2) is mixed with the montmorillonite suspension, heated and mechanically stirred, and the mixed suspension is then centrifuged and washed with deionized water, the white precipitate is ultrasonically vibrated, and dried and ground to obtain a carbon forming agent.

7. The flame retardant EPDM rubber tube according to claim 1, characterized in that: The antioxidant is antioxidant RD; the accelerator is a mixture of accelerator CZ and accelerator M; and the vulcanizing agent is sulfur S-80.

8. The flame retardant EPDM rubber tube according to claim 7, characterized in that: The aluminum hydroxide is prepared by mixing aluminum hydroxide with a particle size of 18 to 20 μm and aluminum hydroxide with a particle size of 4 to 5 μm.

9. The flame retardant EPDM rubber tube according to claim 8, characterized in that: The aluminum hydroxide is modified aluminum hydroxide; The modified aluminum hydroxide is modified by using dodecyltrimethoxysilane; specifically, the aluminum hydroxide is stirred and dried at 60-80° C. for 2 hours, a xylene solution of dodecyltrimethoxysilane with a concentration of 25-35% is added, the reaction is stirred at a temperature of 120-140° C. for 0.5-1 hour, filtered and dried to obtain the modified aluminum hydroxide; the mass ratio of the aluminum hydroxide to dodecyltrimethoxysilane is 100:1.5-2.

5.

10. The method for preparing a flame retardant EPDM rubber tube according to any one of claims 1 to 9, characterized in that: The steps include: (1) Cooling water is passed through the internal mixer, the temperature of the internal mixer working room is controlled at 45-55°C, the speed is 32-35 rpm, and EPDM rubber is added and mixed for 1-3 minutes; (2) Add zinc oxide, stearic acid and antioxidant and mix for 5 to 6 minutes; (3) The internal mixer continues to pass cooling water, and carbon black, paraffin oil, and flame retardant are added to the internal mixer for mixing. When the temperature of the internal mixer reaches 140-150° C., the masterbatch is discharged and cooled to room temperature; (4) Cooling water is passed through the internal mixer to control the working temperature of the internal mixer at 90-95°C, and the masterbatch is added. The mixture is mixed for 1-2 minutes, and the accelerator and the vulcanizer are added. When the temperature of the internal mixer reaches 105-110°C, the rubber is discharged to obtain the EPDM rubber compound.

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