Carboxylated nitrile rubber composition and preparation process thereof

Abstract

The invention discloses a carboxy nitrile rubber composition and a preparation process thereof. The carboxy nitrile rubber composition is prepared from the following components in parts by weight: 100-120 parts of modified carboxy nitrile rubber, 50-60 parts of modified reinforcing filler, 5-15 parts of plasticizer, 2-5 parts of sulfur, 3-8 parts of metal oxide, 1-3 parts of anti-aging agent and 1-2 parts of processing aid. According to the modified carboxy nitrile rubber, a modified boron nitride nanosheet dispersion liquid, a nano graphene oxide dispersion liquid, an aramid nanofiber dispersion liquid and carboxy nitrile rubber latex are uniformly mixed and then flocculated and coagulated, so that the tensile strength is further enhanced, the breaking elongation time is prolonged, and the modified carboxy nitrile rubber is resistant to organic solvent permeation. The silane modified white carbon black enables the activity of the filler to XNBR to be increased, so that valuable vulcanized rubber performance is brought, and the mechanical property of the carboxy nitrile rubber is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a carboxyl nitrile rubber composition and a preparation process thereof. Background Art

[0002] Carboxyl nitrile rubber (XNBR) is because of having introduced carboxyl group in nitrile rubber, so its oil resistance is further enhanced, and simultaneously the introducing of carboxyl group also improves the tensile strength, tear strength, elastic modulus and hardness, wear resistance, tackiness and ozone aging resistance of nitrile rubber, particularly improves the tensile strength under nitrile rubber high temperature.In addition, introducing carboxyl group can also improve the polarity of nitrile rubber molecule, increase the compatibility with polyvinyl chloride, phenolic resin etc.XNBR is mainly used in the preparation of rubber products, adhesives, mechanical parts that have higher requirements on oil resistance and wear resistance, as dynamic seals, high pressure seals, wear-resistant parts, high temperature oil-resistant parts for aircraft, automobile and important mechanical equipment, also can be blended with PVC, CR, NBR etc. to improve its oil resistance and wear resistance.

[0003] US2003109642 introduces a method for simultaneously selectively hydrogenating and crosslinking a polymer comprising at least one unsaturated conjugated diene, an unsaturated nitrile, and an unsaturated carboxylic acid monomer under the action of a coupling agent or a condensing agent. The hydrogenation is selectively performed only on the double bonds of the carbon chain, thereby avoiding hydrogenation of the nitrile or carboxyl groups in the polymer. This special polymer material has excellent properties. JP2000026547 introduces a method for preparing carboxylated nitrile rubber by soap-free emulsion polymerization. The main invention of this patent is that (1) the terpolymerization reaction of 1,3-butadiene, acrylonitrile, and methacrylic acid occurs in a reactor containing a water-soluble polymer medium containing potassium persulfate, with the total amount of materials accounting for at least 60% of the reactor volume; (2) in order to prepare a seed polymer latex, the reaction needs to be carried out at 25-80°C until the solid content reaches 20%; (3) 1,3-butadiene, acrylonitrile, and potassium persulfate are added to the seed latex and polymerized for 1 hour to prepare a second polymer medium; (4) the reaction is continued in the second polymer medium for at least half an hour to finally prepare a carboxylated nitrile latex. EP0955324A1 also introduces a method for preparing carboxylated nitrile latex by soap-free emulsion polymerization, which belongs to the same patent family as JP2000026547.

[0004] Patent CN200510029573.8 discloses a method for preparing carboxylated nitrile butadiene latex, which uses butadiene, acrylonitrile, unsaturated carboxylic acid and unsaturated carboxylic acid ester, a polymerization temperature of 5-9°C, initiated by isopropyl hydroperoxide, an emulsifier is added in batches, and the reaction is terminated when the conversion rate reaches 90% to prepare carboxylated nitrile butadiene latex; Patent CN97107122.5 discloses a process for preparing carboxylated nitrile butadiene rubber powder, which first uses butadiene and acrylonitrile to prepare nitrile rubber latex by sulfate initiation at 45-75°C, then adds carboxyl groups and their peroxides at 65-70°C to prepare a micronized suspension, which is then treated to obtain carboxylated nitrile butadiene rubber powder.

[0005] Patent CN1296991A provides a rubber mixture comprising 0.1-3% by weight of rubber having hydroxyl and / or carboxyl groups, 5-500 parts by weight of hydrophobized oxidized and / or silicate fillers based on 100 parts by weight of rubber, and optional rubber, rubber additives and crosslinking agents. The rubber mixture is suitable for preparing rubber vulcanized products with improved physical properties, particularly improved dynamic damping performance, reduced mill wear and improved wet skid resistance. Summary of the Invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a carboxylated nitrile rubber composition having the characteristics of high tensile strength, high oil resistance, high temperature resistance, and resistance to organic solvents. The composition can be used as a material for seals, oil-resistant hoses, wear-resistant linings, and other products in oilfield equipment, the automotive industry, hydraulic systems, and the aerospace field.

[0007] Technical solution: A carboxyl nitrile rubber composition, comprising the following components in parts by weight: 100-120 parts of modified carboxyl nitrile rubber, 50-60 parts of modified reinforcing filler, 5-15 parts of plasticizer, 2-5 parts of sulfur, 3-8 parts of metal oxide, 1-3 parts of antioxidant, and 1-2 parts of processing aid;

[0008] The modified carboxylated nitrile rubber was prepared by continuously stirring a modified boron nitride nanosheet dispersion, a nanographene oxide dispersion, an aramid nanofiber dispersion, and a carboxylated nitrile latex at 900 rpm for 4 hours, then adding 8% NaCl as a flocculant for coagulation, filtering and washing the solid product three times, and vacuum drying it at 60°C for 20 hours.

[0009] The modified reinforcing filler is modified silica, which is prepared by dissolving organosilane in ethanol, adding silica to the solution, stirring at room temperature for 30 minutes, distilling the solution at 110°C, and vacuum drying the modified silica at 50°C for 48 hours.

[0010] Preferably, a modified boron nitride nanosheet dispersion is prepared by placing boron nitride and sodium nitrate in a flask, adding concentrated sulfuric acid, and stirring for 30 minutes in an ice bath. Potassium permanganate is divided into five equal portions, one portion of which is added to the flask every 15 minutes. Stirring is continued for 40 minutes after addition. The temperature is raised to 35°C, and the reaction is continued for 4 hours. Deionized water is then slowly added, controlling the reaction temperature to no more than 110°C. After the deionized water is added, the reactants are removed, filtered, acid-washed, washed with water, and vacuum-dried at 60°C for 20 hours. The mixture is then added to polyvinylpyrrolidone latex and dispersed at 25,000 rpm for 1 hour to obtain a modified boron nitride nanosheet dispersion.

[0011] Preferably, the method for preparing a nano-graphene oxide dispersion is as follows: graphene and sodium nitrate are placed in a flask, concentrated sulfuric acid is added, and the mixture is stirred in an ice bath for 30 minutes. Potassium permanganate is divided into 5 equal portions, and one portion is added to the flask every 15 minutes. After the addition, stirring is continued for 40 minutes. The temperature is raised to 35°C, and the reaction is continued for 4 hours. Deionized water is then slowly added, and the reaction temperature is controlled not to exceed 110°C. After the deionized water is added, the reactants are poured out, filtered, acid-washed, and washed with water. Deionized water is added, and high-speed shear dispersion is performed at 25,000 rpm for 30 minutes to obtain a nano-graphene oxide dispersion.

[0012] A preferred method for preparing an aramid nanofiber dispersion is to slowly add aramid fibers to a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 at 0-5°C, stirring for 6 hours, slowly add the reaction solution to ice water, filter, wash until neutral, and vacuum dry at 50°C for 48 hours. Hydrolyzed aramid fibers are added to deionized water, followed by the addition of APTES, and then dispersed at 25,000 rpm for 2 hours to obtain an aramid nanofiber dispersion.

[0013] Preferably, the mass fraction of the modified boron nitride nanosheets in the modified carboxylated nitrile rubber is 1%, the mass fraction of the nanographene oxide in the modified carboxylated nitrile rubber is 2%, and the mass fraction of the aramid nanofiber in the modified carboxylated nitrile rubber is 5%.

[0014] Preferably, the plasticizer is one of DOP, DOS, and TP-95.

[0015] Preferably, the metal oxide is one or more of zinc oxide and magnesium oxide.

[0016] Preferably, the antioxidant is one or more of RD and 4010NA.

[0017] Preferably, the processing aid is one or more of stearic acid and paraffin.

[0018] A method for preparing a carboxylated nitrile rubber composition comprises the following steps:

[0019] S1. The modified carboxyl nitrile rubber, 1 / 2 modified reinforcing filler, plasticizer, and processing aid are mixed in an internal mixer at a mixing temperature of 50° C. for 5 min. 1 / 2 modified reinforcing filler, metal oxide, and antioxidant are added at a mixing temperature of 80° C. for 8 min, and the mixture is allowed to stand at room temperature for 6 h. S1. The modified carboxyl nitrile rubber, 1 / 2 modified reinforcing filler, plasticizer, and processing aid are mixed in an internal mixer at a mixing temperature of 40° C. for 15 min.

[0020] S2. The rubber compound mixed in step S1 is vulcanized in a flat vulcanizer at a vulcanizing temperature of 150-170° C., a pressure of 10-20 MPa, and a vulcanizing time of 20-45 minutes.

[0021] Beneficial effects:

[0022] (1) The present invention mixes modified boron nitride nanosheet dispersion, nanographene oxide dispersion, aramid nanofiber dispersion and carboxyl nitrile latex through modified carboxyl nitrile rubber, and then flocculates and coagulates to further enhance tensile strength, elongation at break and resistance to organic solvent penetration.

[0023] (2) The reinforcing filler in the present invention reacts organosilane with silica to obtain modified silica, which increases the activity of the filler on XNBR, thereby bringing valuable vulcanized rubber properties and further improving the mechanical properties of carboxylated nitrile rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 2 is a performance test comparison diagram of the embodiment and the comparative example. DETAILED DESCRIPTION

[0025] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] A carboxyl nitrile rubber composition is obtained by the following preparation method:

[0028] (1) Preparation of modified boron nitride nanosheet dispersion: 100g of boron nitride and 50g of sodium nitrate were placed in a flask, 2L of concentrated sulfuric acid was added and stirred in an ice bath for 30min. 300g of potassium permanganate was divided into 5 parts, and 1 part was added to the flask every 15min. After the addition, stirring was continued for 40min, the temperature was raised to 35℃, and the reaction was continued for 4h. Then 4L of deionized water was slowly added, and the reaction temperature was controlled not to exceed 110℃. After the deionized water was added, the reactants were poured out and filtered, acid-washed, washed with water, and vacuum-dried at 60℃ for 20h. Added to polyvinylpyrrolidone latex, high-speed shear dispersion was performed at 25000rpm for 1h to obtain a modified boron nitride nanosheet dispersion;

[0029] (2) Preparation of nano-graphene oxide dispersion: 100g of graphene and 50g of sodium nitrate were placed in a flask, and 2L of concentrated sulfuric acid was added and stirred in an ice bath for 30min. 300g of potassium permanganate was divided into 5 parts, and 1 part was added to the flask every 15min. After the addition, stirring was continued for 40min, and the temperature was raised to 35°C, and the reaction was continued for 4h. Then 4L of deionized water was slowly added, and the reaction temperature was controlled not to exceed 110°C. After the deionized water was added, the reactants were poured out, filtered, acid-washed, and washed with water. 2L of deionized water was added, and high-speed shear dispersion at 25000rpm was performed for 30min to obtain nano-graphene oxide dispersion;

[0030] (3) Preparation of aramid nanofiber dispersion: 1.5 L of concentrated sulfuric acid and 0.5 L of concentrated nitric acid were used to slowly add 100 g of aramid fiber at 0-5°C and stirred for 6 hours. The reaction solution was slowly added to ice water, filtered, washed until neutral, and vacuum dried at 50°C for 48 hours. The hydrolyzed aramid fiber was added to deionized water, APTES was added, and high-speed shear dispersion reaction was carried out at 25,000 rpm for 2 hours to obtain an aramid nanofiber dispersion.

[0031] (4) Preparation of modified carboxylated nitrile rubber: 20 g of modified boron nitride nanosheet dispersion, 40 g of nanographene oxide dispersion, 100 g of aramid nanofiber dispersion and 2000 g of carboxylated nitrile latex were stirred continuously at 900 rpm for 4 h, and then 80 g of sodium chloride flocculant was added for coagulation. The solid product was filtered and washed three times, and then vacuum dried at 60 °C for 20 h.

[0032] (5) Preparation of modified reinforcing filler: 200 mmol of organosilane was dissolved in ethanol, and then 600 g of white carbon black was added to the solution. The mixture was stirred at room temperature for 30 min, and the solution was distilled at 110 °C. The modified white carbon black was vacuum dried at 50 °C for 48 h.

[0033] (6) 1000 g of modified carboxyl nitrile rubber, 250 g of modified reinforcing filler, 50 g of DOP, and 10 g of stearic acid were mixed in an internal mixer at a mixing temperature of 50 ° C for 5 min; 250 g of modified reinforcing filler, 30 g of zinc oxide, and 10 g of RD were added, the mixing temperature was controlled at 80 ° C, the mixing was carried out for 8 min, and the mixture was placed at room temperature for 6 h; 20 g of sulfur was added, the mixing temperature was controlled at 40 ° C, and the mixture was carried out for 15 min;

[0034] (7) The rubber compound mixed in step (6) was vulcanized on a flat vulcanizer at a temperature of 150° C., a pressure of 10 MPa, and a vulcanization time of 20 minutes.

[0035] Example 2

[0036] A carboxyl nitrile rubber composition is obtained by the following preparation method:

[0037] (1) Preparation of modified boron nitride nanosheet dispersion: 100g of boron nitride and 50g of sodium nitrate were placed in a flask, 2L of concentrated sulfuric acid was added and stirred in an ice bath for 30min. 300g of potassium permanganate was divided into 5 parts, and 1 part was added to the flask every 15min. After the addition, stirring was continued for 40min, the temperature was raised to 35℃, and the reaction was continued for 4h. Then 4L of deionized water was slowly added, and the reaction temperature was controlled not to exceed 110℃. After the deionized water was added, the reactants were poured out and filtered, acid-washed, washed with water, and vacuum-dried at 60℃ for 20h. Added to polyvinylpyrrolidone latex, high-speed shear dispersion was performed at 25000rpm for 1h to obtain a modified boron nitride nanosheet dispersion;

[0038] (2) Preparation of nano-graphene oxide dispersion: 100g of graphene and 50g of sodium nitrate were placed in a flask, and 2L of concentrated sulfuric acid was added and stirred in an ice bath for 30min. 300g of potassium permanganate was divided into 5 parts, and 1 part was added to the flask every 15min. After the addition, stirring was continued for 40min, and the temperature was raised to 35°C, and the reaction was continued for 4h. Then 4L of deionized water was slowly added, and the reaction temperature was controlled not to exceed 110°C. After the deionized water was added, the reactants were poured out, filtered, acid-washed, and washed with water. 2L of deionized water was added, and high-speed shear dispersion at 25000rpm was performed for 30min to obtain nano-graphene oxide dispersion;

[0039] (3) Preparation of aramid nanofiber dispersion: 1.5 L of concentrated sulfuric acid and 0.5 L of concentrated nitric acid were used to slowly add 100 g of aramid fiber at 0-5°C and stirred for 6 hours. The reaction solution was slowly added to ice water, filtered, washed until neutral, and vacuum dried at 50°C for 48 hours. The hydrolyzed aramid fiber was added to deionized water, APTES was added, and high-speed shear dispersion reaction was carried out at 25,000 rpm for 2 hours to obtain an aramid nanofiber dispersion.

[0040] (4) Preparation of modified carboxylated nitrile rubber: 20 g of modified boron nitride nanosheet dispersion, 40 g of nanographene oxide dispersion, 100 g of aramid nanofiber dispersion and 2000 g of carboxylated nitrile latex were stirred continuously at 900 rpm for 4 h, and then 80 g of sodium chloride flocculant was added for coagulation. The solid product was filtered and washed three times, and then vacuum dried at 60 °C for 20 h.

[0041] (5) Preparation of modified reinforcing filler: 200 mmol of organosilane was dissolved in ethanol, and then 600 g of white carbon black was added to the solution. The mixture was stirred at room temperature for 30 min, and the solution was distilled at 110 °C. The modified white carbon black was vacuum dried at 50 °C for 48 h.

[0042] (6) 1100 g of modified carboxyl nitrile rubber, 280 g of modified reinforcing filler, 50 g of DOP, 50 g of DOS, and 15 g of paraffin were mixed in an internal mixer at a mixing temperature of 50 ° C for 5 min; 280 g of modified reinforcing filler, 55 g of magnesium oxide, and 20 g of 4010NA were added, the mixing temperature was controlled at 80 ° C, the mixing was carried out for 8 min, and the mixture was placed at room temperature for 6 h; 35 g of sulfur was added, the mixing temperature was controlled at 40 ° C, and the mixture was carried out for 15 min;

[0043] (7) The rubber compound mixed in step (6) was vulcanized on a flat vulcanizer at a temperature of 160° C., a pressure of 15 MPa, and a vulcanization time of 30 minutes.

[0044] Example 3

[0045] A carboxyl nitrile rubber composition is obtained by the following preparation method:

[0046] (1) Preparation of modified boron nitride nanosheet dispersion: 100g of boron nitride and 50g of sodium nitrate were placed in a flask, 2L of concentrated sulfuric acid was added and stirred in an ice bath for 30min. 300g of potassium permanganate was divided into 5 parts, and 1 part was added to the flask every 15min. After the addition, stirring was continued for 40min, the temperature was raised to 35℃, and the reaction was continued for 4h. Then 4L of deionized water was slowly added, and the reaction temperature was controlled not to exceed 110℃. After the deionized water was added, the reactants were poured out and filtered, acid-washed, washed with water, and vacuum-dried at 60℃ for 20h. Added to polyvinylpyrrolidone latex, high-speed shear dispersion was performed at 25000rpm for 1h to obtain a modified boron nitride nanosheet dispersion;

[0047] (2) Preparation of nano-graphene oxide dispersion: 100g of graphene and 50g of sodium nitrate were placed in a flask, and 2L of concentrated sulfuric acid was added and stirred in an ice bath for 30min. 300g of potassium permanganate was divided into 5 parts, and 1 part was added to the flask every 15min. After the addition, stirring was continued for 40min, and the temperature was raised to 35°C, and the reaction was continued for 4h. Then 4L of deionized water was slowly added, and the reaction temperature was controlled not to exceed 110°C. After the deionized water was added, the reactants were poured out, filtered, acid-washed, and washed with water. 2L of deionized water was added, and high-speed shear dispersion at 25000rpm was performed for 30min to obtain nano-graphene oxide dispersion;

[0048] (3) Preparation of aramid nanofiber dispersion: 1.5 L of concentrated sulfuric acid and 0.5 L of concentrated nitric acid were used to slowly add 100 g of aramid fiber at 0-5°C and stirred for 6 hours. The reaction solution was slowly added to ice water, filtered, washed until neutral, and vacuum dried at 50°C for 48 hours. The hydrolyzed aramid fiber was added to deionized water, APTES was added, and high-speed shear dispersion reaction was carried out at 25,000 rpm for 2 hours to obtain an aramid nanofiber dispersion.

[0049] (4) Preparation of modified carboxylated nitrile rubber: 20 g of modified boron nitride nanosheet dispersion, 40 g of nanographene oxide dispersion, 100 g of aramid nanofiber dispersion and 2000 g of carboxylated nitrile latex were stirred continuously at 900 rpm for 4 h, and then 80 g of sodium chloride flocculant was added for coagulation. The solid product was filtered and washed three times, and then vacuum dried at 60 °C for 20 h.

[0050] (5) Preparation of modified reinforcing filler: 200 mmol of organosilane was dissolved in ethanol, and then 600 g of white carbon black was added to the solution. The mixture was stirred at room temperature for 30 min, and the solution was distilled at 110 °C. The modified white carbon black was vacuum dried at 50 °C for 48 h.

[0051] (6) 1200 g of modified carboxyl nitrile rubber, 300 g of modified reinforcing filler, 75 g of DOS, 75 g of TP-95, 10 g of stearic acid, and 10 g of paraffin were mixed in an internal mixer at a mixing temperature of 50 ° C for 5 min; 300 g of modified reinforcing filler, 40 g of zinc oxide, 40 g of magnesium oxide, 15 g of RD, and 15 g of 4010NA were added, the mixing temperature was controlled at 80 ° C, the mixing was carried out for 8 min, and the mixture was placed at room temperature for 6 h; 50 g of sulfur was added, the mixing temperature was controlled at 40 ° C, and the mixture was mixed for 15 min;

[0052] (7) The rubber compound mixed in step (6) was vulcanized on a flat vulcanizer at a temperature of 170° C., a pressure of 20 MPa, and a vulcanization time of 45 minutes.

[0053] Comparative Example 1

[0054] A carboxyl nitrile rubber composition is obtained by the following preparation method:

[0055] (1) Preparation of modified reinforcing filler: 200 mmol of organosilane was dissolved in ethanol, and then 600 g of white carbon black was added to the solution. The mixture was stirred at room temperature for 30 min, and the solution was distilled at 110 °C. The modified white carbon black was vacuum dried at 50 °C for 48 h.

[0056] (2) 1100 g of carboxylated nitrile rubber, 280 g of modified reinforcing filler, 50 g of DOP, 50 g of DOS, and 15 g of paraffin were mixed in an internal mixer at a mixing temperature of 50 ° C for 5 min; 280 g of modified reinforcing filler, 55 g of magnesium oxide, and 20 g of 4010NA were added, the mixing temperature was controlled at 80 ° C, the mixing was carried out for 8 min, and the mixture was allowed to stand at room temperature for 6 h; 35 g of sulfur was added, the mixing temperature was controlled at 40 ° C, and the mixture was mixed for 15 min;

[0057] (3) The rubber compound mixed in step (2) was vulcanized on a flat vulcanizer at a vulcanizing temperature of 160° C., a pressure of 15 MPa, and a vulcanizing time of 30 minutes.

[0058] Comparative Example 2

[0059] A carboxyl nitrile rubber composition is obtained by the following preparation method:

[0060] (1) Preparation of modified boron nitride nanosheet dispersion: 100g of boron nitride and 50g of sodium nitrate were placed in a flask, 2L of concentrated sulfuric acid was added and stirred in an ice bath for 30min. 300g of potassium permanganate was divided into 5 parts, and 1 part was added to the flask every 15min. After the addition, stirring was continued for 40min, the temperature was raised to 35℃, and the reaction was continued for 4h. Then 4L of deionized water was slowly added, and the reaction temperature was controlled not to exceed 110℃. After the deionized water was added, the reactants were poured out and filtered, acid-washed, washed with water, and vacuum-dried at 60℃ for 20h. Added to polyvinylpyrrolidone latex, high-speed shear dispersion was performed at 25000rpm for 1h to obtain a modified boron nitride nanosheet dispersion;

[0061] (2) Preparation of nano-graphene oxide dispersion: 100g of graphene and 50g of sodium nitrate were placed in a flask, and 2L of concentrated sulfuric acid was added and stirred in an ice bath for 30min. 300g of potassium permanganate was divided into 5 parts, and 1 part was added to the flask every 15min. After the addition, stirring was continued for 40min, and the temperature was raised to 35°C, and the reaction was continued for 4h. Then 4L of deionized water was slowly added, and the reaction temperature was controlled not to exceed 110°C. After the deionized water was added, the reactants were poured out, filtered, acid-washed, and washed with water. 2L of deionized water was added, and high-speed shear dispersion at 25000rpm was performed for 30min to obtain nano-graphene oxide dispersion;

[0062] (3) Preparation of aramid nanofiber dispersion: 1.5 L of concentrated sulfuric acid and 0.5 L of concentrated nitric acid were used to slowly add 100 g of aramid fiber at 0-5°C and stirred for 6 hours. The reaction solution was slowly added to ice water, filtered, washed until neutral, and vacuum dried at 50°C for 48 hours. The hydrolyzed aramid fiber was added to deionized water, APTES was added, and high-speed shear dispersion reaction was carried out at 25,000 rpm for 2 hours to obtain an aramid nanofiber dispersion.

[0063] (4) Preparation of modified carboxylated nitrile rubber: 20 g of modified boron nitride nanosheet dispersion, 40 g of nanographene oxide dispersion, 100 g of aramid nanofiber dispersion and 2000 g of carboxylated nitrile latex were stirred continuously at 900 rpm for 4 h, and then 80 g of sodium chloride flocculant was added for coagulation. The solid product was filtered and washed three times, and then vacuum dried at 60 °C for 20 h.

[0064] (5) 1100 g of modified carboxyl nitrile rubber, 280 g of reinforcing filler carbon black, 50 g of DOP, 50 g of DOS, and 15 g of paraffin were mixed in an internal mixer at a mixing temperature of 50 ° C for 5 min; 280 g of reinforcing filler carbon black, 55 g of magnesium oxide, and 20 g of 4010NA were added, the mixing temperature was controlled at 80 ° C, the mixing was carried out for 8 min, and the mixture was placed at room temperature for 6 h; 35 g of sulfur was added, the mixing temperature was controlled at 40 ° C, and the mixture was carried out for 15 min;

[0065] (6) The rubber compound mixed in step (5) was vulcanized on a flat vulcanizer at a vulcanizing temperature of 160° C., a pressure of 15 MPa, and a vulcanizing time of 30 minutes.

[0066] Comparative Example 3

[0067] A carboxyl nitrile rubber composition is obtained by the following preparation method:

[0068] (1) 1100 g of carboxylic nitrile rubber, 280 g of reinforcing filler carbon black, 50 g of DOP, 50 g of DOS, and 15 g of paraffin were mixed in an internal mixer at a mixing temperature of 50 ° C for 5 min; 280 g of reinforcing filler carbon black, 55 g of magnesium oxide, and 20 g of 4010NA were added, the mixing temperature was controlled at 80 ° C, the mixing was carried out for 8 min, and the mixture was placed at room temperature for 6 h; 35 g of sulfur was added, the mixing temperature was controlled at 40 ° C, and the mixture was mixed for 15 min;

[0069] (2) The rubber compound mixed in step (1) was vulcanized on a flat vulcanizer at a vulcanizing temperature of 160° C., a pressure of 15 MPa, and a vulcanizing time of 30 minutes.

[0070] Performance testing methods

[0071] (1) Tensile strength: tested according to GB / T 528 standard method;

[0072] (2) Elongation at break: tested according to ISO 34-1 standard method;

[0073] (3) Hardness: tested according to ISO 7619-1 standard method;

[0074] (4) Solvent resistance: tested according to ASTM D471 standard.

[0075] The performance test comparison results of the above embodiments and comparative examples are as follows: Figure 1As shown. The results show that the carboxyl nitrile rubber composition provided by the present invention has excellent tensile strength, elongation at break, and resistance to organic solvent penetration. It can be seen from Examples 1 to 3 and Comparative Examples 1 to 3 that (1) the modified carboxyl nitrile rubber, modified reinforcing filler, plasticizer, sulfur, metal oxide, antioxidant, and processing aid improve the mechanical properties, elongation at break, and resistance to organic solvent penetration of the carboxyl nitrile rubber composition through synergistic interactions; (2) Silane-modified white carbon black increases the activity of the filler on XNBR, thereby bringing valuable vulcanized rubber properties, further improving the mechanical properties of the carboxyl nitrile rubber.

[0076] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A carboxyl nitrile rubber composition, characterized in that The invention comprises the following components in parts by weight: 100-120 parts of modified carboxyl nitrile rubber, 50-60 parts of modified reinforcing filler, 5-15 parts of plasticizer, 2-5 parts of sulfur, 3-8 parts of metal oxide, 1-3 parts of antioxidant, and 1-2 parts of processing aid; The modified carboxylated nitrile rubber was prepared by continuously stirring a modified boron nitride nanosheet dispersion, a nanographene oxide dispersion, an aramid nanofiber dispersion, and a carboxylated nitrile latex at 900 rpm for 4 hours, then adding 8% NaCl as a flocculant for coagulation, filtering and washing the solid product three times, and vacuum drying it at 60°C for 20 hours. The modified reinforcing filler is modified silica, which is prepared by dissolving organosilane in ethanol, then adding silica to the solution, stirring at room temperature for 30 minutes, distilling the solution at 110°C, and vacuum drying the modified silica at 50°C for 48 hours.

2. carboxyl nitrile rubber composition according to claim 1, characterized in that, The modified boron nitride nanosheet dispersion was prepared as follows: boron nitride and sodium nitrate were placed in a flask, concentrated sulfuric acid was added, and the mixture was stirred in an ice bath for 30 minutes. Potassium permanganate was divided into five equal portions, one portion of which was added to the flask every 15 minutes. Stirring was continued for 40 minutes after addition. The temperature was raised to 35°C and the reaction was continued for 4 hours. Deionized water was then slowly added, controlling the reaction temperature not to exceed 110°C. After the deionized water was added, the reaction mixture was removed, filtered, acid-washed, washed with water, and vacuum-dried at 60°C for 20 hours. The mixture was then added to polyvinylpyrrolidone latex and dispersed at 25,000 rpm for 1 hour to obtain a modified boron nitride nanosheet dispersion.

3. carboxyl nitrile rubber composition according to claim 1, characterized in that, The nano-graphene oxide dispersion was prepared by placing graphene and sodium nitrate in a flask, adding concentrated sulfuric acid, and stirring for 30 minutes in an ice bath. Potassium permanganate was then divided into five equal portions, one portion of which was added to the flask every 15 minutes. Stirring was continued for 40 minutes after addition. The temperature was raised to 35°C, and the reaction was continued for 4 hours. Deionized water was then slowly added, controlling the reaction temperature to no more than 110°C. After the deionized water was added, the reaction mixture was removed, filtered, acid-washed, and rinsed with water. Deionized water was then added, and high-speed shear dispersion was performed at 25,000 rpm for 30 minutes to obtain the nano-graphene oxide dispersion.

4. carboxyl nitrile rubber composition according to claim 1, characterized in that, The aramid nanofiber dispersion was prepared by slowly adding a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 to aramid fibers at 0-5°C. The mixture was stirred and reacted for 6 hours. The reaction solution was then slowly added to ice water, filtered, washed until neutral, and dried under vacuum at 50°C for 48 hours. The hydrolyzed aramid fibers were then added to deionized water, followed by the addition of APTES. The mixture was then subjected to high-speed shear dispersion at 25,000 rpm for 2 hours to obtain the aramid nanofiber dispersion.

5. The carboxyl nitrile rubber composition according to claim 1, wherein The mass fraction of the modified boron nitride nanosheets in the modified carboxyl nitrile rubber is 1%, the mass fraction of the nano-graphene oxide in the modified carboxyl nitrile rubber is 2%, and the mass fraction of the aramid nanofiber in the modified carboxyl nitrile rubber is 5%.

6. The carboxyl nitrile rubber composition according to claim 1, wherein The plasticizer is one of DOP, DOS, and TP-95.

7. The carboxyl nitrile rubber composition according to claim 1, wherein The metal oxide is one or more of zinc oxide and magnesium oxide.

8. carboxyl nitrile rubber composition according to claim 1, characterized in that, The antioxidant is one or more of RD and 4010NA.

9. The carboxyl nitrile rubber composition according to claim 1, wherein The processing aid is one or more of stearic acid and paraffin.

10. A method for preparing the carboxyl nitrile rubber composition according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. The modified carboxyl nitrile rubber, 1 / 2 modified reinforcing filler, plasticizer, and processing aid are mixed in an internal mixer at a mixing temperature of 50° C. for 5 min. 1 / 2 modified reinforcing filler, metal oxide, and antioxidant are added at a mixing temperature of 80° C. for 8 min, and the mixture is allowed to stand at room temperature for 6 h. S1. The modified carboxyl nitrile rubber, 1 / 2 modified reinforcing filler, plasticizer, and processing aid are mixed in an internal mixer at a mixing temperature of 40° C. for 15 min. S2. The rubber compound mixed in step S1 is vulcanized in a flat vulcanizer at a vulcanizing temperature of 150-170° C., a pressure of 10-20 MPa, and a vulcanizing time of 20-45 minutes.

Images