Flexible corrosion-resistant rubber water pipe for automobile heat dissipation and preparation process thereof

Abstract

This invention discloses a flexible, corrosion-resistant rubber water hose for automotive cooling and its preparation process, relating to the field of rubber materials technology. This application uses ethylene propylene diene monomer (EPDM) rubber as the matrix material. EPDM rubber possesses excellent weather resistance, coolant corrosion resistance, and flexibility, making it suitable as a substrate for automotive cooling water hoses. This application uses vinyl-terminated polydimethylsiloxane and fluorostyrene monomers to graft the rubber. The siloxane chains of the vinyl-terminated polydimethylsiloxane exhibit high flexibility and excellent corrosion resistance, thereby improving the hose's flexibility and resistance to high and low temperatures. The addition of N,N'-(4,4'-methylenediphenyl)bismaleimide introduces flexible chains, enhancing the rubber's flexibility. The addition of 4-chloro-2-fluorostyrene introduces fluorine groups into the fluorostyrene monomer, improving the hose's corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of rubber materials technology, specifically to a flexible, corrosion-resistant rubber water pipe for automotive heat dissipation and its preparation process. Background Technology

[0002] Rubber water hoses are a core component of automotive thermal management systems, responsible for transporting coolant and maintaining the operating temperature of critical components such as the engine, battery pack, and motor. With the development of the automotive industry, higher performance requirements have been placed on rubber water hoses: they need to be flexible for easy assembly and vibration damping, possess excellent corrosion resistance to withstand the erosion of acidic and alkaline media, and also have good mechanical strength.

[0003] Existing technologies mostly use a single type of EPDM rubber as the rubber matrix, which has limited resistance to strong corrosion and is prone to aging and cracking after long-term use. The reinforcing material is mainly short fiber, and the inertness of the fiber surface makes it incompatible with the rubber matrix, which will lead to a decline in the performance of the rubber water pipe.

[0004] To address the aforementioned issues, this application provides a flexible, corrosion-resistant rubber water hose for automotive heat dissipation and its manufacturing process. Summary of the Invention

[0005] The purpose of this invention is to provide a flexible, corrosion-resistant rubber water pipe for automotive heat dissipation and its manufacturing process, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A flexible, corrosion-resistant rubber water hose for automotive heat dissipation, the rubber water hose comprising an inner rubber layer and an outer rubber layer; the inner rubber layer is composed of the following components: modified EPDM rubber, carbon black, ammonium polyphosphate, calcium carbonate, paraffin oil, zinc oxide, stearic acid, polyethylene glycol, vulcanizing agent, and antioxidant; the outer rubber layer is composed of the following components: modified EPDM rubber, carbon black, carbon fiber, ammonium polyphosphate, calcium carbonate, paraffin oil, zinc oxide, stearic acid, polyethylene glycol, vulcanizing agent, and antioxidant. The modified EPDM rubber is prepared as follows: EPDM rubber is melted at 160-165℃, dicumyl peroxide, fluorostyrene monomer, and vinyl-terminated polydimethylsiloxane are added, and the mixture is plasticized. Then, N,N'-(4,4'-methylenediphenyl)bismaleimide, lignin composite aerogel, and dicumyl peroxide are added and mixed evenly to obtain a compound. The compound is then hot-pressed and annealed to obtain the modified EPDM rubber.

[0007] A more optimized method for preparing the fluorostyrene monomer is as follows: take sodium hydroxide solution and 3-hydroxypropylfuran, stir for 1-2 h, then add a mixed solution of 4-chloro-2-fluorostyrene and toluene, add tetrabutylammonium hydroxide, stir in an ice-water bath for 48-50 h, stop the reaction, extract and recover the organic matter, remove water, and rotary evaporate to obtain the fluorostyrene monomer.

[0008] A more optimized method for preparing the lignin composite aerogel includes the following steps: S1: Add sodium alginate to deionized water and stir until homogeneous to obtain sodium alginate aqueous solution. Add sodium alginate to ferric chloride aqueous solution and crosslink for 24-26 hours. Filter, wash, dry and pulverize to obtain ferric alginate. S2: Take sodium lignosulfonate and sodium hydroxide solution, stir evenly, add calcium carbonate, continue stirring for 10-15 min, add chitosan, iron alginate, graphene and ammonium polyphosphate, stir for 5-6 h, add gluconolactone and deionized water mixture, stir evenly, let stand and freeze dry to obtain lignin composite aerogel.

[0009] Ideally, the concentration of the ferric chloride aqueous solution is 5-5.5 mol / L.

[0010] More preferably, the graphene is amino-branched graphene, and its preparation method is as follows: take graphene, add it to a mixed solution of anhydrous ethanol and deionized water, disperse it ultrasonically, add 3-aminopropyltriethoxysilane dropwise, heat to 60-65℃, stir, reflux, wash, and dry, add anhydrous ethanol, disperse it ultrasonically, add polydipentaerythritol hexaacrylate, stir for 3-4 hours, filter, wash, and dry to obtain graphene hybrid; add anhydrous ethanol, disperse it ultrasonically, then add tris(2-aminoethyl)amine, stir the reaction for 5-6 hours, filter, wash, and dry to obtain amino-branched graphene.

[0011] In a more optimized manner, the inner layer rubber is composed of the following components, by weight: 100-110 parts modified EPDM rubber, 80-100 parts carbon black, 12-18 parts ammonium polyphosphate, 20-25 parts calcium carbonate, 45-55 parts paraffin oil, 3-5 parts zinc oxide, 1.5-2 parts stearic acid, 2-4 parts polyethylene glycol, 3-5 parts vulcanizing agent, and 2-3 parts antioxidant.

[0012] In a more optimized manner, the outer layer adhesive is composed of the following components, by weight: 100-110 parts modified EPDM rubber, 80-100 parts carbon black, 30-35 parts carbon fiber, 20-25 parts calcium carbonate, 45-55 parts paraffin oil, 3-5 parts zinc oxide, 1.5-2 parts stearic acid, 2-4 parts polyethylene glycol, 3-5 parts vulcanizing agent, 2-3 parts antioxidant, and 12-18 parts ammonium polyphosphate.

[0013] A manufacturing process for a flexible, corrosion-resistant rubber water hose for automotive heat dissipation includes the following steps: Step 1: Take modified EPDM rubber, carbon black, ammonium polyphosphate, calcium carbonate, paraffin oil, zinc oxide, stearic acid, polyethylene glycol, vulcanizing agent, and antioxidant as the inner layer rubber substrate; take modified EPDM rubber, carbon black, carbon fiber, ammonium polyphosphate, calcium carbonate, paraffin oil, zinc oxide, stearic acid, polyethylene glycol, vulcanizing agent, and antioxidant as the outer layer rubber substrate; Step 2: Mix the inner layer rubber substrate and the outer layer rubber substrate separately to obtain the inner layer compound and the outer layer compound; Step 3: Extrude the inner and outer layer compounded rubber to obtain a double-layer composite tube preform, and vulcanize it at 160-165℃ and 0.55-0.65MPa for 20-30 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This application uses EPDM rubber as the matrix material of the rubber. EPDM rubber has excellent weather resistance, coolant corrosion resistance and flexibility, and is suitable as a base material for automotive radiator pipes.

[0015] 2. This application uses vinyl-terminated polydimethylsiloxane and fluorostyrene monomers to graft rubber. The siloxane chains of the vinyl-terminated polydimethylsiloxane exhibit high flexibility and excellent corrosion resistance, thereby improving the flexibility and high / low temperature resistance of the water pipe. The addition of N,N'-(4,4'-methylenediphenyl)bismaleimide introduces flexible chains, enhancing the rubber's flexibility. The addition of 4-chloro-2-fluorostyrene introduces fluorine groups into the fluorostyrene monomer, improving the water pipe's corrosion resistance.

[0016] 3. This application prepares a lignin composite aerogel. The addition of lignin composite aerogel enhances the thermal insulation of the water pipe and the interfacial compatibility between the filler and the substrate, further improving the corrosion resistance of the water pipe. Lignin has high carbon content and rigid phenylpropane units, which can endow the aerogel with excellent mechanical properties and flame retardant properties.

[0017] 4. This application adds chitosan, resulting in lignin-based composite aerogels containing amino groups, which enhances their compatibility with rubber water pipes, thereby improving the pipes' heat dissipation and corrosion resistance. The amino groups on the amino-based graphene synergistically enhance the compatibility with the EPDM rubber matrix, preventing aerogel aggregation. The high thermal conductivity of graphene complements the porous insulation properties of the aerogel, accelerating heat dissipation and delaying the aging of the rubber water pipes. This invention uses ferric alginate to prepare the composite aerogel; the flexible segments in ferric alginate can provide stress buffering, improving the mechanical properties of the water pipes. Detailed Implementation

[0018] 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.

[0019] The sources and types of substances involved in this application are not specifically limited. Exemplary examples include: ethylene propylene diene monomer (EPDM) rubber: CAS No.: 25038-36-2, available from Wuhan Jixin Yibang Biotechnology Co., Ltd.; antioxidant: antioxidant 4020; vulcanizing agent: dicumyl peroxide; carbon fiber: 1-2mm; polyethylene glycol: item number: V32174, available from Shanghai Yuanye Biotechnology Co., Ltd.; 4-chloro-2-fluorostyrene: CAS No.: 711017-44-6, available from Shanghai Bide Pharmaceutical Technology Co., Ltd.; vinyl-terminated polydimethylsiloxane: CAS No.: 68083-1 9-2 can be purchased from Hubei Zhonglong Kangcheng Fine Chemical Co., Ltd.; N,N'-(4,4'-methylenediphenyl)bismaleimide: CAS No.: 13676-54-5, can be purchased from Shanghai Haohong Biomedical Technology Co., Ltd.; Polydipentaerythritol hexaacrylate: Item No.: Y54775, can be purchased from Shanghai Yuanye Biotechnology Co., Ltd.; Tris(2-aminoethyl)amine: can be purchased from Merck; Graphene: Thickness: 0.8-1.2nm, Diameter: 0.5-5µm, Model: M931285, can be purchased from Maclean's; Gluconolactone: can be purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0020] Example 1: A manufacturing process for a flexible, corrosion-resistant rubber water hose for automotive heat dissipation, comprising the following steps: S1: The rubber hose consists of an inner rubber layer and an outer rubber layer; the inner rubber layer is 0.4mm thick and the outer rubber layer is 1.8mm thick. The inner layer rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 16 parts ammonium polyphosphate, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, and 2.5 parts antioxidant. The outer layer of rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 32 parts carbon fiber, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, 2.5 parts antioxidant, and 16 parts ammonium polyphosphate. The inner layer rubber and the outer layer rubber are mixed separately to obtain inner layer compound and outer layer compound; The inner and outer compound rubber compounds are extruded to obtain a double-layer composite tube preform, which is then vulcanized at 162℃ and 0.60MPa for 25 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation. S1-1: Preparation of modified EPDM rubber: Take 150g of 33% sodium hydroxide solution and 32g of 3-hydroxypropylfuran, stir for 1.5h, then add 20g of a mixed solution of 4-chloro-2-fluorostyrene and 25mL of toluene, add 17g of tetrabutylammonium hydroxide, stir in an ice-water bath for 49h, stop the reaction, extract and recover the organic matter, remove water and rotary evaporate to obtain fluorostyrene monomer; Take 100g of EPDM rubber, melt it at 162℃, add 1g of dicumyl peroxide, 2.2g of fluorostyrene monomer, and 1.5g of vinyl-terminated polydimethylsiloxane, and masticate it. Then add 0.5g of N,N'-(4,4'-methylenediphenyl)bismaleimide, 3g of lignin composite aerogel, and 0.5g of dicumyl peroxide, and mix them evenly to obtain a compound. Hot press and anneal the compound to obtain modified EPDM rubber. S1-1-1: Preparation of lignin composite aerogel: Sodium alginate was added to deionized water and stirred until homogeneous to prepare a 2% sodium alginate aqueous solution. Then, it was added to a 5 mol / L ferric chloride aqueous solution and crosslinked for 25 h. After filtration, washing, drying, and pulverizing to 200 mesh, ferric alginate was obtained. Take 100 mg of graphene and add it to a mixed solution of 100 mL anhydrous ethanol and 20 mL deionized water. Disperse by sonication, add 20 mL of 3-aminopropyltriethoxysilane dropwise, heat to 62 °C, stir, reflux, wash, and dry. Add 100 mL of anhydrous ethanol and disperse by sonication. Add 20 mL of polydipentaerythritol hexaacrylate and stir for 3.5 h. Filter, wash, and dry to obtain graphene hybrid. Add 100 mL of anhydrous ethanol and disperse by sonication. Then add 30 mL of tris(2-aminoethyl)amine and stir for 5.5 h. Filter, wash, and dry to obtain amino-branched graphene. Take 0.4g sodium lignosulfonate and 10mL of 0.05mol / L sodium hydroxide solution, stir well, add 0.03g calcium carbonate, continue stirring for 12min, add 0.5g chitosan, 0.3g ferric alginate, 0.1g amino-branched graphene and 2g ammonium polyphosphate, stir for 5.5h, add a mixture of 0.15g gluconolactone and 2mL deionized water, stir well, let stand and freeze dry to obtain lignin composite aerogel.

[0021] Example 2: A manufacturing process for a flexible, corrosion-resistant rubber water hose for automotive heat dissipation, comprising the following steps: S1: The rubber hose consists of an inner rubber layer and an outer rubber layer; the inner rubber layer is 0.4mm thick and the outer rubber layer is 1.8mm thick. The inner layer rubber is composed of the following components, by weight: 100 parts modified EPDM rubber, 80 parts carbon black, 12 parts ammonium polyphosphate, 20 parts calcium carbonate, 45 parts paraffin oil, 3 parts zinc oxide, 1.5 parts stearic acid, 2 parts polyethylene glycol, 3 parts vulcanizing agent, and 2 parts antioxidant. The outer layer of rubber is composed of the following components, by weight: 100 parts modified EPDM rubber, 80 parts carbon black, 30 parts carbon fiber, 20 parts calcium carbonate, 45 parts paraffin oil, 3 parts zinc oxide, 1.5 parts stearic acid, 2 parts polyethylene glycol, 3 parts vulcanizing agent, 2 parts antioxidant, and 12 parts ammonium polyphosphate. The inner layer rubber and the outer layer rubber are mixed separately to obtain inner layer compound and outer layer compound; The inner and outer compound rubbers are extruded to obtain a double-layer composite tube preform, which is then vulcanized at 160℃ and 0.55MPa for 20 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation. S1-1: Preparation of modified EPDM rubber: Take 150g of 33% sodium hydroxide solution and 32g of 3-hydroxypropylfuran, stir for 1h, then add 20g of a mixed solution of 4-chloro-2-fluorostyrene and 25mL of toluene, add 17g of tetrabutylammonium hydroxide, stir in an ice-water bath for 48h, stop the reaction, extract and recover the organic matter, remove water and rotary evaporate to obtain fluorostyrene monomer; Take 100g of EPDM rubber, melt it at 160℃, add 1g of dicumyl peroxide, 2.2g of fluorostyrene monomer, and 1.5g of vinyl-terminated polydimethylsiloxane, and masticate it. Then add 0.5g of N,N'-(4,4'-methylenediphenyl)bismaleimide, 3g of lignin composite aerogel, and 0.5g of dicumyl peroxide, and mix them evenly to obtain a compound. Hot press and anneal the compound to obtain modified EPDM rubber. S1-1-1: Preparation of lignin composite aerogel: Sodium alginate was added to deionized water and stirred until homogeneous to prepare a 2% sodium alginate aqueous solution. Then, it was added to a 5 mol / L ferric chloride aqueous solution and crosslinked for 24 hours. After filtration, washing, drying, and pulverizing to 200 mesh, ferric alginate was obtained. Take 100 mg of graphene and add it to a mixed solution of 100 mL anhydrous ethanol and 20 mL deionized water. Disperse by sonication, add 20 mL of 3-aminopropyltriethoxysilane dropwise, heat to 60 °C, stir, reflux, wash, and dry. Add 100 mL of anhydrous ethanol and disperse by sonication. Add 20 mL of polydipentaerythritol hexaacrylate and stir for 3 h. Filter, wash, and dry to obtain graphene hybrid. Add 100 mL of anhydrous ethanol and disperse by sonication, then add 30 mL of tris(2-aminoethyl)amine and stir for 5 h. Filter, wash, and dry to obtain amino-branched graphene. Take 0.4g sodium lignosulfonate and 10mL of 0.05mol / L sodium hydroxide solution, stir well, add 0.03g calcium carbonate, continue stirring for 10min, add 0.5g chitosan, 0.3g ferric alginate, 0.1g amino-branched graphene and 2g ammonium polyphosphate, stir for 5h, add a mixture of 0.15g gluconolactone and 2mL deionized water, stir well, let stand and freeze dry to obtain lignin composite aerogel.

[0022] Example 3: A manufacturing process for a flexible, corrosion-resistant rubber water hose for automotive heat dissipation, comprising the following steps: S1: The rubber hose consists of an inner rubber layer and an outer rubber layer; the inner rubber layer is 0.5mm thick and the outer rubber layer is 2.2mm thick. The inner layer rubber is composed of the following components, by weight: 110 parts modified EPDM rubber, 100 parts carbon black, 18 parts ammonium polyphosphate, 25 parts calcium carbonate, 55 parts paraffin oil, 5 parts zinc oxide, 2 parts stearic acid, 4 parts polyethylene glycol, 5 parts vulcanizing agent, and 3 parts antioxidant. The outer layer of rubber is composed of the following components, by weight: 110 parts modified EPDM rubber, 100 parts carbon black, 35 parts carbon fiber, 25 parts calcium carbonate, 55 parts paraffin oil, 5 parts zinc oxide, 2 parts stearic acid, 4 parts polyethylene glycol, 5 parts vulcanizing agent, 3 parts antioxidant, and 18 parts ammonium polyphosphate. The inner layer rubber and the outer layer rubber are mixed separately to obtain inner layer compound and outer layer compound; The inner and outer compound rubber compounds are extruded to obtain a double-layer composite tube preform, which is then vulcanized at 165℃ and 0.65MPa for 30 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation. S1-1: Preparation of modified EPDM rubber: Take 150g of 33% sodium hydroxide solution and 32g of 3-hydroxypropylfuran, stir for 2h, then add 20g of a mixed solution of 4-chloro-2-fluorostyrene and 25mL of toluene, add 17g of tetrabutylammonium hydroxide, stir for 50h in an ice-water bath, stop the reaction, extract and recover the organic matter, remove water and rotary evaporate to obtain fluorostyrene monomer; Take 100g of EPDM rubber, melt it at 165℃, add 1g of dicumyl peroxide, 2.2g of fluorostyrene monomer, and 1.5g of vinyl-terminated polydimethylsiloxane, and masticate it. Then add 0.5g of N,N'-(4,4'-methylenediphenyl)bismaleimide, 3g of lignin composite aerogel, and 0.5g of dicumyl peroxide, and mix them evenly to obtain a compound. Hot press and anneal the compound to obtain modified EPDM rubber. S1-1-1: Preparation of lignin composite aerogel: Sodium alginate was added to deionized water and stirred until homogeneous to prepare a 2% sodium alginate aqueous solution. Then, it was added to a 5 mol / L ferric chloride aqueous solution and crosslinked for 26 hours. After filtration, washing, drying, and pulverizing to 200 mesh, ferric alginate was obtained. Take 100 mg of graphene and add it to a mixed solution of 100 mL anhydrous ethanol and 20 mL deionized water. Disperse by sonication, add 20 mL of 3-aminopropyltriethoxysilane dropwise, heat to 65 °C, stir, reflux, wash, and dry. Add 100 mL of anhydrous ethanol and disperse by sonication. Add 20 mL of polydipentaerythritol hexaacrylate and stir for 4 h. Filter, wash, and dry to obtain graphene hybrid. Add 100 mL of anhydrous ethanol and disperse by sonication. Then add 30 mL of tris(2-aminoethyl)amine and stir for 6 h. Filter, wash, and dry to obtain amino-branched graphene. Take 0.4g sodium lignosulfonate and 10mL of 0.05mol / L sodium hydroxide solution, stir well, add 0.03g calcium carbonate, continue stirring for 15min, add 0.5g chitosan, 0.3g ferric alginate, 0.1g amino-branched graphene and 2g ammonium polyphosphate, stir for 6h, add a mixture of 0.15g gluconolactone and 2mL deionized water, stir well, let stand and freeze dry to obtain lignin composite aerogel.

[0023] Comparative Example 1: Grafting of rubber without using fluorostyrene monomers, otherwise the same as in Example 1: S1: The rubber hose consists of an inner rubber layer and an outer rubber layer; the inner rubber layer is 0.4mm thick and the outer rubber layer is 1.8mm thick. The inner layer rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 16 parts ammonium polyphosphate, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, and 2.5 parts antioxidant. The outer layer of rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 32 parts carbon fiber, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, 2.5 parts antioxidant, and 16 parts ammonium polyphosphate. The inner layer rubber and the outer layer rubber are mixed separately to obtain inner layer compound and outer layer compound; The inner and outer compound rubber compounds are extruded to obtain a double-layer composite tube preform, which is then vulcanized at 162℃ and 0.60MPa for 25 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation. S1-1: Preparation of modified EPDM rubber: Take 100g of EPDM rubber, melt it at 162℃, add 1g of dicumyl peroxide and 1.5g of vinyl-terminated polydimethylsiloxane, and masticate it. Then add 0.5g of N,N'-(4,4'-methylenediphenyl)bismaleimide, 3g of lignin composite aerogel, and 0.5g of dicumyl peroxide, and mix them evenly to obtain a compound. Hot press and anneal the compound to obtain modified EPDM rubber.

[0024] Comparative Example 2: No lignin-based composite aerogel was added; all other aspects were the same as in Example 1. S1: The rubber hose consists of an inner rubber layer and an outer rubber layer; the inner rubber layer is 0.4mm thick and the outer rubber layer is 1.8mm thick. The inner layer rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 16 parts ammonium polyphosphate, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, and 2.5 parts antioxidant. The outer layer of rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 32 parts carbon fiber, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, 2.5 parts antioxidant, and 16 parts ammonium polyphosphate. The inner layer rubber and the outer layer rubber are mixed separately to obtain inner layer compound and outer layer compound; The inner and outer compound rubber compounds are extruded to obtain a double-layer composite tube preform, which is then vulcanized at 162℃ and 0.60MPa for 25 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation. S1-1: Preparation of modified EPDM rubber: Take 150g of 33% sodium hydroxide solution and 32g of 3-hydroxypropylfuran, stir for 1.5h, then add 20g of a mixed solution of 4-chloro-2-fluorostyrene and 25mL of toluene, add 17g of tetrabutylammonium hydroxide, stir in an ice-water bath for 49h, stop the reaction, extract and recover the organic matter, remove water and rotary evaporate to obtain fluorostyrene monomer; Take 100g of EPDM rubber, melt it at 162℃, add 1g of dicumyl peroxide, 2.2g of fluorostyrene monomer, and 1.5g of vinyl-terminated polydimethylsiloxane, and masticate it. Then add 0.5g of N,N'-(4,4'-methylenediphenyl)bismaleimide and 0.5g of dicumyl peroxide, and mix them evenly to obtain a compound. Hot press and anneal the compound to obtain modified EPDM rubber.

[0025] Comparative Example 3: No ferric alginate added, otherwise the same as Example 1: S1: The rubber hose consists of an inner rubber layer and an outer rubber layer; the inner rubber layer is 0.4mm thick and the outer rubber layer is 1.8mm thick. The inner layer rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 16 parts ammonium polyphosphate, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, and 2.5 parts antioxidant. The outer layer of rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 32 parts carbon fiber, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, 2.5 parts antioxidant, and 16 parts ammonium polyphosphate. The inner layer rubber and the outer layer rubber are mixed separately to obtain inner layer compound and outer layer compound; The inner and outer compound rubber compounds are extruded to obtain a double-layer composite tube preform, which is then vulcanized at 162℃ and 0.60MPa for 25 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation. S1-1: Preparation of modified EPDM rubber: Take 150g of 33% sodium hydroxide solution and 32g of 3-hydroxypropylfuran, stir for 1.5h, then add 20g of a mixed solution of 4-chloro-2-fluorostyrene and 25mL of toluene, add 17g of tetrabutylammonium hydroxide, stir in an ice-water bath for 49h, stop the reaction, extract and recover the organic matter, remove water and rotary evaporate to obtain fluorostyrene monomer; Take 100g of EPDM rubber, melt it at 162℃, add 1g of dicumyl peroxide, 2.2g of fluorostyrene monomer, and 1.5g of vinyl-terminated polydimethylsiloxane, and masticate it. Then add 0.5g of N,N'-(4,4'-methylenediphenyl)bismaleimide, 3g of lignin composite aerogel, and 0.5g of dicumyl peroxide, and mix them evenly to obtain a compound. Hot press and anneal the compound to obtain modified EPDM rubber. S1-1-1: Preparation of lignin composite aerogel: Take 100 mg of graphene and add it to a mixed solution of 100 mL anhydrous ethanol and 20 mL deionized water. Disperse by sonication, add 20 mL of 3-aminopropyltriethoxysilane dropwise, heat to 62 °C, stir, reflux, wash, and dry. Add 100 mL of anhydrous ethanol and disperse by sonication. Add 20 mL of polydipentaerythritol hexaacrylate and stir for 3.5 h. Filter, wash, and dry to obtain graphene hybrid. Add 100 mL of anhydrous ethanol and disperse by sonication. Then add 30 mL of tris(2-aminoethyl)amine and stir for 5.5 h. Filter, wash, and dry to obtain amino-branched graphene. Take 0.4g of sodium lignosulfonate and 10mL of 0.05mol / L sodium hydroxide solution, stir well, add 0.03g of calcium carbonate, continue stirring for 12min, add 0.5g of chitosan, 0.1g of amino-branched graphene and 2g of ammonium polyphosphate, stir for 5.5h, add a mixture of 0.15g of gluconolactone and 2mL of deionized water, stir well, let stand and freeze dry to obtain lignin composite aerogel.

[0026] Comparative Example 4: No amination treatment was performed on the graphene; all other aspects were the same as in Example 1. S1: The rubber hose consists of an inner rubber layer and an outer rubber layer; the inner rubber layer is 0.4mm thick and the outer rubber layer is 1.8mm thick. The inner layer rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 16 parts ammonium polyphosphate, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, and 2.5 parts antioxidant. The outer layer of rubber is composed of the following components, by weight: 105 parts modified EPDM rubber, 90 parts carbon black, 32 parts carbon fiber, 22 parts calcium carbonate, 50 parts paraffin oil, 4 parts zinc oxide, 1.8 parts stearic acid, 3 parts polyethylene glycol, 4 parts vulcanizing agent, 2.5 parts antioxidant, and 16 parts ammonium polyphosphate. The inner layer rubber and the outer layer rubber are mixed separately to obtain inner layer compound and outer layer compound; The inner and outer compound rubber compounds are extruded to obtain a double-layer composite tube preform, which is then vulcanized at 162℃ and 0.60MPa for 25 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation. S1-1: Preparation of modified EPDM rubber: Take 150g of 33% sodium hydroxide solution and 32g of 3-hydroxypropylfuran, stir for 1.5h, then add 20g of a mixed solution of 4-chloro-2-fluorostyrene and 25mL of toluene, add 17g of tetrabutylammonium hydroxide, stir in an ice-water bath for 49h, stop the reaction, extract and recover the organic matter, remove water and rotary evaporate to obtain fluorostyrene monomer; Take 100g of EPDM rubber, melt it at 162℃, add 1g of dicumyl peroxide, 2.2g of fluorostyrene monomer, and 1.5g of vinyl-terminated polydimethylsiloxane, and masticate it. Then add 0.5g of N,N'-(4,4'-methylenediphenyl)bismaleimide, 3g of lignin composite aerogel, and 0.5g of dicumyl peroxide, and mix them evenly to obtain a compound. Hot press and anneal the compound to obtain modified EPDM rubber. S1-1-1: Preparation of lignin composite aerogel: Sodium alginate was added to deionized water and stirred until homogeneous to prepare a 2% sodium alginate aqueous solution. Then, it was added to a 5 mol / L ferric chloride aqueous solution and crosslinked for 25 h. After filtration, washing, drying, and pulverizing to 200 mesh, ferric alginate was obtained. Take 0.4g of sodium lignosulfonate and 10mL of 0.05mol / L sodium hydroxide solution, stir well, add 0.03g of calcium carbonate, continue stirring for 12min, add 0.5g of chitosan, 0.3g of ferric alginate, 0.1g of graphene and 2g of ammonium polyphosphate, stir for 5.5h, add a mixture of 0.15g of glucono-delta-lactone and 2mL of deionized water, stir well, let stand, freeze dry to obtain lignin composite aerogel.

[0027] experiment: The rubber water pipes prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The thermal conductivity of the rubber water pipes was measured using the heat shield plate method, and the thermal conductivity was used to evaluate the heat dissipation effect of the rubber. The tensile strength of the rubber water pipes was tested according to GB / T 528-2019. The rubber water pipes were immersed in a 20wt% sodium hydroxide solution, and after several hours, they were removed and the corrosion resistance of the water pipe surface was observed. The data obtained are shown in Table 1 below. Table 1

[0028] Conclusion: The data comparison in the table shows that in Comparative Example 1, without grafting the rubber with fluorostyrene monomers, the corrosion resistance of the water pipe decreased. In Comparative Example 2, without adding lignin composite aerogel, the heat dissipation and corrosion resistance of the water pipe decreased. In Comparative Example 3, without adding ferric alginate, the tensile strength of the water pipe decreased. In Comparative Example 4, without amination of graphene, the compatibility between graphene and the EPDM rubber matrix decreased, aerogel agglomeration occurred, and the heat dissipation, corrosion resistance, and mechanical properties of the rubber water pipe all decreased. Examples 1-3 of this application introduced fluorine groups into the fluorostyrene monomers, improving the corrosion resistance of the water pipe. The addition of lignin composite aerogel enhanced the heat insulation of the water pipe and the interfacial compatibility between the filler and the substrate, further improving the corrosion resistance of the water pipe. Using ferric alginate to prepare the composite aerogel, the flexible segments in ferric alginate can provide stress buffering, improving the mechanical properties of the water pipe, enabling its tensile strength to reach 12 MPa.

[0029] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A flexible, corrosion-resistant rubber water hose for automotive heat dissipation, characterized in that: The rubber water pipe comprises an inner rubber layer and an outer rubber layer; the inner rubber layer is composed of the following components: modified EPDM rubber, carbon black, ammonium polyphosphate, calcium carbonate, paraffin oil, zinc oxide, stearic acid, polyethylene glycol, vulcanizing agent, and antioxidant; the outer rubber layer is composed of the following components: modified EPDM rubber, carbon black, carbon fiber, ammonium polyphosphate, calcium carbonate, paraffin oil, zinc oxide, stearic acid, polyethylene glycol, vulcanizing agent, and antioxidant. The modified EPDM rubber is prepared as follows: EPDM rubber is melted at 160-165℃, dicumyl peroxide, fluorostyrene monomer, and vinyl-terminated polydimethylsiloxane are added, and the mixture is plasticized. Then, N,N'-(4,4'-methylenediphenyl)bismaleimide, lignin composite aerogel, and dicumyl peroxide are added and mixed evenly to obtain a compound. The compound is then hot-pressed and annealed to obtain the modified EPDM rubber.

2. The flexible corrosion-resistant rubber water hose for automotive heat dissipation according to claim 1, characterized in that: The method for preparing the fluorostyrene monomer is as follows: take sodium hydroxide solution and 3-hydroxypropylfuran, stir for 1-2 h, then add a mixed solution of 4-chloro-2-fluorostyrene and toluene, add tetrabutylammonium hydroxide, stir in an ice-water bath for 48-50 h, stop the reaction, extract and recover the organic matter, remove water, and rotary evaporate to obtain the fluorostyrene monomer.

3. The flexible corrosion-resistant rubber water hose for automotive heat dissipation according to claim 1, characterized in that: The preparation method of the lignin composite aerogel includes the following steps: S1: Add sodium alginate to deionized water and stir until homogeneous to obtain sodium alginate aqueous solution. Add sodium alginate to ferric chloride aqueous solution and crosslink for 24-26 hours. Filter, wash, dry and pulverize to obtain ferric alginate. S2: Take sodium lignosulfonate and sodium hydroxide solution, stir evenly, add calcium carbonate, continue stirring for 10-15 min, add chitosan, iron alginate, graphene and ammonium polyphosphate, stir for 5-6 h, add gluconolactone and deionized water mixture, stir evenly, let stand and freeze dry to obtain lignin composite aerogel.

4. The flexible corrosion-resistant rubber water hose for automotive heat dissipation according to claim 3, characterized in that: The concentration of the ferric chloride aqueous solution is 5-5.5 mol / L.

5. The flexible corrosion-resistant rubber water hose for automotive heat dissipation according to claim 3, characterized in that: The graphene is amino-branched graphene, and its preparation method is as follows: Take graphene, add it to a mixed solution of anhydrous ethanol and deionized water, disperse it by ultrasonication, add 3-aminopropyltriethoxysilane dropwise, heat to 60-65℃, stir, reflux, wash, and dry, add anhydrous ethanol, disperse it by ultrasonication, add polydipentaerythritol hexaacrylate, stir for 3-4 hours, filter, wash, and dry to obtain graphene hybrid; add anhydrous ethanol, disperse it by ultrasonication, then add tris(2-aminoethyl)amine, stir and react for 5-6 hours, filter, wash, and dry to obtain amino-branched graphene.

6. The flexible corrosion-resistant rubber water hose for automotive heat dissipation according to claim 1, characterized in that: The inner layer rubber is composed of the following components, by weight: 100-110 parts modified EPDM rubber, 80-100 parts carbon black, 12-18 parts ammonium polyphosphate, 20-25 parts calcium carbonate, 45-55 parts paraffin oil, 3-5 parts zinc oxide, 1.5-2 parts stearic acid, 2-4 parts polyethylene glycol, 3-5 parts vulcanizing agent, and 2-3 parts antioxidant.

7. The flexible corrosion-resistant rubber water hose for automotive heat dissipation according to claim 1, characterized in that: The outer layer of rubber is composed of the following components, by weight: 100-110 parts modified EPDM rubber, 80-100 parts carbon black, 30-35 parts carbon fiber, 20-25 parts calcium carbonate, 45-55 parts paraffin oil, 3-5 parts zinc oxide, 1.5-2 parts stearic acid, 2-4 parts polyethylene glycol, 3-5 parts vulcanizing agent, 2-3 parts antioxidant, and 12-18 parts ammonium polyphosphate.

8. A manufacturing process for a flexible, corrosion-resistant rubber water hose for automotive heat dissipation, characterized in that: Includes the following steps: Step 1: Take modified EPDM rubber, carbon black, ammonium polyphosphate, calcium carbonate, paraffin oil, zinc oxide, stearic acid, polyethylene glycol, vulcanizing agent, and antioxidant as the inner layer rubber substrate; take modified EPDM rubber, carbon black, carbon fiber, ammonium polyphosphate, calcium carbonate, paraffin oil, zinc oxide, stearic acid, polyethylene glycol, vulcanizing agent, and antioxidant as the outer layer rubber substrate; Step 2: Mix the inner layer rubber substrate and the outer layer rubber substrate separately to obtain the inner layer compound and the outer layer compound; Step 3: Extrude the inner and outer layer compounded rubber to obtain a double-layer composite tube preform, and vulcanize it at 160-165℃ and 0.55-0.65MPa for 20-30 minutes to obtain a flexible and corrosion-resistant rubber water pipe for automotive heat dissipation.

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