A solvent-resistant high-strength sealing rubber and a processing method thereof

Abstract

The present invention relates to the field of sealing rubber, and specifically to a solvent-resistant high-strength sealing rubber and a processing method thereof. The present invention discloses the following method: firstly, a macromolecular hydrophobic initiator is prepared using butyl methacrylate as a raw material, and then the macromolecular hydrophobic initiator is polymerized with butene glycol and 2-acrylamide-2-methylpropanesulfonic acid to obtain an amphiphilic copolymer; then, the amphiphilic copolymer is used to modify natural rubber, and the modified rubber is chemically cross-linked with a polyurethane prepolymer and isocyanate-modified graphene oxide to obtain a sealing rubber; the sealing rubber has good water absorption performance and strong tolerance to salt solutions, and can be applied to working environments such as high-mineralization groundwater and oilfield water.

Description

Technical Field

[0001] The invention relates to the technical field of sealing rubbers, in particular to a solvent-resistant high-strength sealing rubber and a processing method thereof. Background Art

[0002] Rubber is a common polymer material that is elastic at room temperature and has reversible deformation properties under certain external forces. It is often used to prepare sealing materials. Generally, rubber can be divided into two types: natural rubber and synthetic rubber. The latter is made by polymerizing different monomers, with various types and excellent performance. It overcomes many shortcomings of the former in application and is highly favored by the market.

[0003] Among synthetic rubbers, water-swelling rubber contains hydrophilic materials and hydrophobic matrix, so it has both hydrophilicity and elasticity. After contact with water, solution, etc., water-swelling rubber can not only absorb water and retain water, but also maintain good mechanical strength. It has important application value in construction engineering, oil field mining and precision instruments. However, due to the poor compatibility between hydrophilic materials and hydrophobic matrix, long-term use in solutions with high mineralization will cause hydrophilic materials to migrate to the rubber surface, causing problems such as rubber softening and strength loss, affecting sealing performance, and in severe cases may cause oil and solution leakage, causing adverse effects on the environment. Therefore, it is very necessary to invent a solvent-resistant high-strength sealing rubber. Summary of the invention

[0004] The object of the present invention is to provide a solvent-resistant high-strength sealing rubber and a processing method thereof to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a solvent-resistant high-strength sealing rubber and a processing method thereof, comprising the following steps:

[0006] Step 1: stir and mix butyl methacrylate, initiator azobisisobutyronitrile, and molecular weight regulator 1,1-diphenylethylene, and heat to react under vacuum. After the reaction is completed, add methanol for precipitation and chloroform for dissolution, and repeat twice to dry to obtain a macromolecular hydrophobic initiator;

[0007] Step 2: adding butenediol, a macromolecular hydrophobic initiator, and 2-acrylamide-2-methylpropanesulfonic acid to toluene, mixing and stirring to obtain a reaction solution, heating the solution under a vacuum environment to react, precipitating the product with acetone, washing with deionized water, and drying the product to obtain an amphiphilic copolymer;

[0008] Step 3: adding graphene oxide to dimethylformamide solvent, ultrasonically dispersing for 2 hours, adding isophorone diisocyanate and continuing ultrasonic dispersion, and then reacting, centrifuging, washing, and vacuum drying to obtain isocyanate-modified graphene oxide;

[0009] Step 4: dehydrate polyethylene glycol, add diphenylmethane diisocyanate and react to obtain a polyurethane prepolymer; mix the natural rubber latex and the amphiphilic copolymer, add ammonium persulfate, sodium thiosulfate and N,N'-methylenebisacrylamide, react, dry and purify to obtain a modified rubber;

[0010] Step 5: Mix the modified rubber, polyurethane prepolymer, isocyanate-modified graphene oxide, antioxidant, active zinc oxide, and vulcanizing agent diisopropylbenzene peroxide, perform vulcanization treatment, and perform film pressing to obtain a solvent-resistant high-strength sealing rubber.

[0011] Furthermore, in step 1, the reaction temperature of the macromolecular hydrophobic initiator is 70-75° C., and the reaction time is 20-25 h.

[0012] Furthermore, in step 1, the initiator is azobisisobutyronitrile and the molecular weight regulator is 1,1-diphenylethylene.

[0013] Furthermore, in step 2, the reaction temperature of the amphiphilic copolymer is 80-90° C., and the reaction time is 8-10 h.

[0014] Furthermore, in step 2, the contents of the components in the reaction solution are, by weight percentage, 20-35% of butene glycol, 5-10% of a macromolecular hydrophobic initiator, 20-30% of 2-acrylamido-2-methylpropanesulfonic acid, and 20-50% of toluene.

[0015] Furthermore, in step 3, the reaction temperature of isocyanate-modified graphene oxide is 70-80° C., and the reaction time is 25-30 h.

[0016] Furthermore, in step 4, the amounts of the components used are, by weight, 100 parts of natural rubber latex, 15 to 18 parts of amphiphilic copolymer, 0.3 to 0.5 parts of ammonium persulfate, 0.3 to 0.5 parts of sodium thiosulfate, and 0.01 to 0.02 parts of N,N'-methylenebisacrylamide.

[0017] Furthermore, in step 5, the amounts of the components used are, by weight, 100 parts of modified rubber, 20 to 30 parts of polyurethane prepolymer, 4 to 6 parts of isocyanate-modified graphene oxide, 0.5 to 1 part of antioxidant, 1 to 2 parts of active zinc oxide, and 1 to 1.2 parts of vulcanizing agent diisopropyl peroxide.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention uses hydrophilic polyurethane and natural rubber as raw materials to prepare water-absorbing and swelling sealing rubber; firstly, butyl methacrylate is used to prepare a macromolecular hydrophobic initiator, and then the macromolecular hydrophobic initiator is polymerized with butene glycol and 2-acrylamide-2-methylpropanesulfonic acid to obtain an amphiphilic copolymer; on the one hand, since the amphiphilic copolymer has both hydrophobic and hydrophilic effects, after being mixed with rubber latex, the hydrophobic region formed by the hydrophobic group has better compatibility with the rubber latex, which is beneficial to improving the grafting rate, and at the same time, a hydrophilic group is introduced into the modified rubber, and the compatibility with the polyurethane prepolymer is also improved, which can effectively solve the problem of uneven dispersion in the traditional physical blending process; on the other hand, after the amphiphilic copolymer is used to modify the natural rubber, a sulfonic acid group and a hydroxyl group are introduced, and the sulfonic acid group has good salt resistance. After being immersed in a salt solution for a long time, the sealing rubber can still maintain its good mechanical properties. In the conventional rubber / polyurethane material with an interpenetrating polymer network structure, since there are no reactive sites on the rubber molecular chain and the polyurethane molecular chain, the two are only cross-linked by physical means; however, in the present invention, hydroxyl groups are introduced into the modified rubber, which can produce further chemical cross-linking reactions with the isocyanate groups in the polyurethane prepolymer, and the obtained sealing rubber has stronger cross-linking properties. After chemical cross-linking, the polyurethane molecular chain is firmly fixed on the rubber molecular chain, avoiding the phenomenon of "runny nose" caused by the migration of polyurethane to the surface of the sealing rubber. In addition, the present invention also modifies graphene oxide with isocyanate groups, and the modified graphene oxide is not only more compatible with the polyurethane prepolymer, but also reacts with the modified rubber and the polyurethane prepolymer, and is introduced into the molecular chains of rubber and polyurethane by chemical cross-linking, thereby forming a "bridging" effect, so that the rubber and polyurethane are firmly combined, further improving the mechanical strength and service life of the sealing rubber.

[0019] When the water-absorbing rubber comes into contact with water, there are three kinds of interactions: hydrogen bonding between water molecules and polymer materials, interaction between water molecules and hydrophilic groups, and interaction between water molecules and hydrophobic groups. Therefore, when preparing amphiphilic copolymers, the amount of macromolecular hydrophobic initiator needs to be strictly limited. When the macromolecular hydrophobic initiator is excessive, the hydrophobic properties of the amphiphilic copolymer will be enhanced, thereby weakening the water absorption performance of the sealing rubber; when the amount of macromolecular hydrophobic initiator is small, the hydrophobic properties of the amphiphilic polymer are weakened, and the compatibility becomes poor after mixing with rubber latex, which is not conducive to modifying the rubber. Therefore, it is more appropriate to control the macromolecular hydrophobic initiator to account for 5-10% in the reaction system. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Materials used in the present invention and their sources: natural rubber latex comes from Xiangfa Chemical, item number 33-11; graphene oxide comes from Xianfeng Nanomaterials, model XF001H; antioxidant is antioxidant 1010, from Youfeng Chemical; active zinc oxide comes from Yinoda Chemical, purity ≥95%; polyurethane powder comes from Haosheng Engineering Plastics Co., Ltd., brand 1185A.

[0022] Example 1

[0023] Step 1: 1 mol of butyl methacrylate, 1 mol of azobisisobutyronitrile and 2 mol of 1,1-diphenylethylene were stirred and mixed, and heated to 70°C in a vacuum environment for reaction for 20 hours. After the reaction was completed, methanol was added for precipitation and chloroform was used for dissolution. The mixture was repeated twice and dried to obtain a macromolecular hydrophobic initiator.

[0024] Step 2: 35% of butene glycol, 10% of a macromolecular hydrophobic initiator, 30% of 2-acrylamido-2-methylpropanesulfonic acid, and 25% of toluene were mixed according to weight percentage, and stirred evenly to obtain a reaction solution, which was heated to 80° C. under a vacuum environment for reaction for 8 hours, and the product was precipitated with acetone, washed with deionized water, and then dried to obtain an amphiphilic copolymer;

[0025] Step 3: Add 5 g of graphene oxide to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, add 20 g of isophorone diisocyanate and continue ultrasonic dispersion for 30 min, and then react at 70 ° C for 25 h; centrifuge, wash, and vacuum dry for 12 h to obtain isocyanate-modified graphene oxide;

[0026] Step 4: dehydrate 1 mol of polyethylene glycol at 120°C and 0.8 MPa for 2 h, cool to 40°C, add 2 mol of diphenylmethane diisocyanate and mix, react at 80°C for 3 h to obtain a polyurethane prepolymer; mix 100 kg of natural rubber latex and 18 kg of amphiphilic copolymer, add 0.45 kg of ammonium persulfate, 0.3 kg of sodium thiosulfate and 0.02 kg of N,N'-methylenebisacrylamide, heat to 40°C, react for 2 h, dry, and purify to obtain a modified rubber;

[0027] Step 5: 100 kg of modified rubber, 20 kg of polyurethane prepolymer, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide are mixed, vulcanized at 170° C. and 12 MPa for 2 min, and molded into a solvent-resistant high-strength sealing rubber.

[0028] Example 2

[0029] Step 1: 1 mol of butyl methacrylate, 1 mol of azobisisobutyronitrile and 2 mol of 1,1-diphenylethylene were stirred and mixed, and heated to 72°C in a vacuum environment for reaction for 20 hours. After the reaction was completed, methanol was added for precipitation and chloroform was used for dissolution. The mixture was repeated twice and dried to obtain a macromolecular hydrophobic initiator.

[0030] Step 2: 35% of butene glycol, 10% of a macromolecular hydrophobic initiator, 30% of 2-acrylamido-2-methylpropanesulfonic acid, and 25% of toluene were mixed according to weight percentage, and stirred evenly to obtain a reaction solution, which was heated to 82° C. under a vacuum environment for reaction for 8 hours, and the product was precipitated with acetone, washed with deionized water, and then dried to obtain an amphiphilic copolymer;

[0031] Step 3: Add 5 g of graphene oxide to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, add 20 g of isophorone diisocyanate and continue ultrasonic dispersion for 30 min, and then react at 75 ° C for 30 h; centrifuge, wash, and vacuum dry for 12 h to obtain isocyanate-modified graphene oxide;

[0032] Step 4: dehydrate 1 mol of polyethylene glycol at 120°C and 0.8 MPa for 2 h, cool to 40°C, add 2 mol of diphenylmethane diisocyanate and mix, react at 80°C for 3 h to obtain a polyurethane prepolymer; mix 100 kg of natural rubber latex and 18 kg of amphiphilic copolymer, add 0.45 kg of ammonium persulfate, 0.3 kg of sodium thiosulfate and 0.02 kg of N,N'-methylenebisacrylamide, heat to 40°C, react for 3 h, dry, and purify to obtain a modified rubber;

[0033] Step 5: 100 kg of modified rubber, 22 kg of polyurethane prepolymer, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide are mixed, vulcanized at 170° C. and 12 MPa for 2 min, and molded into a solvent-resistant high-strength sealing rubber.

[0034] Example 3

[0035] Step 1: 1 mol of butyl methacrylate, 1 mol of azobisisobutyronitrile and 2 mol of 1,1-diphenylethylene were stirred and mixed, and heated to 73°C in a vacuum environment for reaction for 22 hours. After the reaction was completed, methanol was added for precipitation and chloroform was used for dissolution. The mixture was repeated twice and dried to obtain a macromolecular hydrophobic initiator.

[0036] Step 2: 35% of butene glycol, 10% of a macromolecular hydrophobic initiator, 30% of 2-acrylamido-2-methylpropanesulfonic acid, and 25% of toluene were mixed according to weight percentage, and stirred evenly to obtain a reaction solution, which was heated to 85° C. under a vacuum environment for reaction for 9 hours. The product was precipitated with acetone, washed with deionized water, and then dried to obtain an amphiphilic copolymer;

[0037] Step 3: Add 5 g of graphene oxide to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, add 20 g of isophorone diisocyanate and continue ultrasonic dispersion for 30 min, and then react at 75 ° C for 26 h; centrifuge, wash, and vacuum dry for 12 h to obtain isocyanate-modified graphene oxide;

[0038] Step 4: dehydrate 1 mol of polyethylene glycol at 120°C and 0.8 MPa for 2 h, cool to 40°C, add 2 mol of diphenylmethane diisocyanate and mix, react at 80°C for 3 h to obtain a polyurethane prepolymer; mix 100 kg of natural rubber latex and 18 kg of amphiphilic copolymer, add 0.45 kg of ammonium persulfate, 0.3 kg of sodium thiosulfate and 0.02 kg of N,N'-methylenebisacrylamide, heat to 40°C, react for 2.5 h, dry, and purify to obtain a modified rubber;

[0039] Step 5: 100 kg of modified rubber, 24 kg of polyurethane prepolymer, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide are mixed, vulcanized at 175° C. and 13 MPa for 3 min, and molded into a solvent-resistant high-strength sealing rubber.

[0040] Example 4

[0041] Step 1: 1 mol of butyl methacrylate, 1 mol of azobisisobutyronitrile and 2 mol of 1,1-diphenylethylene were stirred and mixed, and heated to 74°C in a vacuum environment for reaction for 23 hours. After the reaction was completed, methanol was added for precipitation and chloroform was used for dissolution, and the mixture was repeated twice, and dried to obtain a macromolecular hydrophobic initiator;

[0042] Step 2: 35% of butene glycol, 10% of a macromolecular hydrophobic initiator, 30% of 2-acrylamido-2-methylpropanesulfonic acid, and 25% of toluene were mixed according to weight percentage, and stirred evenly to obtain a reaction solution, which was heated to 85° C. under a vacuum environment for reaction for 9 hours. The product was precipitated with acetone, washed with deionized water, and then dried to obtain an amphiphilic copolymer;

[0043] Step 3: Add 5 g of graphene oxide to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, add 20 g of isophorone diisocyanate and continue ultrasonic dispersion for 30 min, and then react at 75 ° C for 26 h; centrifuge, wash, and vacuum dry for 12 h to obtain isocyanate-modified graphene oxide;

[0044] Step 4: dehydrate 1 mol of polyethylene glycol at 120°C and 0.8 MPa for 2 h, cool to 40°C, add 2 mol of diphenylmethane diisocyanate and mix, react at 80°C for 3 h to obtain a polyurethane prepolymer; mix 100 kg of natural rubber latex and 18 kg of amphiphilic copolymer, add 0.45 kg of ammonium persulfate, 0.3 kg of sodium thiosulfate and 0.02 kg of N,N'-methylenebisacrylamide, heat to 45°C, react for 2 h, dry, and purify to obtain a modified rubber;

[0045] Step 5: 100 kg of modified rubber, 25 kg of polyurethane prepolymer, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide are mixed, vulcanized at 180° C. and 12 MPa for 3 min, and molded into a solvent-resistant high-strength sealing rubber.

[0046] Example 5

[0047] Step 1: 1 mol of butyl methacrylate, 1 mol of azobisisobutyronitrile and 2 mol of 1,1-diphenylethylene were stirred and mixed, and heated to 73°C in a vacuum environment for reaction for 22 hours. After the reaction was completed, methanol was added for precipitation and chloroform was used for dissolution. The mixture was repeated twice and dried to obtain a macromolecular hydrophobic initiator.

[0048] Step 2: 35% of butene glycol, 10% of a macromolecular hydrophobic initiator, 30% of 2-acrylamido-2-methylpropanesulfonic acid, and 25% of toluene were mixed according to weight percentage, and stirred evenly to obtain a reaction solution, which was heated to 90° C. under a vacuum environment for reaction for 8 hours. The product was precipitated with acetone, washed with deionized water, and then dried to obtain an amphiphilic copolymer;

[0049] Step 3: Add 5 g of graphene oxide to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, add 20 g of isophorone diisocyanate and continue ultrasonic dispersion for 30 min, and then react at 75 ° C for 28 h; centrifuge, wash, and vacuum dry for 12 h to obtain isocyanate-modified graphene oxide;

[0050] Step 4: dehydrate 1 mol of polyethylene glycol at 120°C and 0.8 MPa for 2 h, cool to 40°C, add 2 mol of diphenylmethane diisocyanate and mix, react at 80°C for 3 h to obtain a polyurethane prepolymer; mix 100 kg of natural rubber latex and 18 kg of amphiphilic copolymer, add 0.45 kg of ammonium persulfate, 0.3 kg of sodium thiosulfate and 0.02 kg of N,N'-methylenebisacrylamide, heat to 50°C, react for 2 h, dry, and purify to obtain a modified rubber;

[0051] Step 5: 100 kg of modified rubber, 27 kg of polyurethane prepolymer, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide are mixed, vulcanized at 185° C. and 14 MPa for 3 min, and molded into a solvent-resistant high-strength sealing rubber.

[0052] Example 6

[0053] Step 1: 1 mol of butyl methacrylate, 1 mol of azobisisobutyronitrile and 2 mol of 1,1-diphenylethylene were stirred and mixed, and heated to 73°C in a vacuum environment for reaction for 22 hours. After the reaction was completed, methanol was added for precipitation and chloroform was used for dissolution. The mixture was repeated twice and dried to obtain a macromolecular hydrophobic initiator.

[0054] Step 2: 35% of butene glycol, 10% of a macromolecular hydrophobic initiator, 30% of 2-acrylamido-2-methylpropanesulfonic acid, and 25% of toluene were mixed according to weight percentage, and stirred evenly to obtain a reaction solution, which was heated to 90° C. under a vacuum environment for reaction for 10 hours. The product was precipitated with acetone, washed with deionized water, and then dried to obtain an amphiphilic copolymer;

[0055] Step 3: Add 5 g of graphene oxide to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, add 20 g of isophorone diisocyanate and continue ultrasonic dispersion for 30 min, and then react at 70 ° C for 28 h; centrifuge, wash, and vacuum dry for 12 h to obtain isocyanate-modified graphene oxide;

[0056] Step 4: dehydrate 1 mol of polyethylene glycol at 120°C and 0.8 MPa for 2 h, cool to 40°C, add 2 mol of diphenylmethane diisocyanate and mix, react at 80°C for 3 h to obtain a polyurethane prepolymer; mix 100 kg of natural rubber latex and 18 kg of amphiphilic copolymer, add 0.45 kg of ammonium persulfate, 0.3 kg of sodium thiosulfate and 0.02 kg of N,N'-methylenebisacrylamide, heat to 50°C, react for 2 h, dry, and purify to obtain a modified rubber;

[0057] Step 5: 100 kg of modified rubber, 30 kg of polyurethane prepolymer, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide are mixed, vulcanized at 190° C. and 15 MPa for 2 min, and molded into a solvent-resistant high-strength sealing rubber.

[0058] Comparative Example 1

[0059] The polyurethane and natural rubber were directly blended by conventional methods, and the preparation parameters were the same as those in Example 1.

[0060] 5 g of graphene oxide was added to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, 20 g of isophorone diisocyanate was added and ultrasonic dispersion was continued for 30 min, and then the mixture was reacted at 70°C for 25 h; the mixture was centrifuged, washed, and vacuum dried for 12 h to obtain isocyanate-modified graphene oxide; 100 kg of natural rubber latex, 20 kg of polyurethane powder, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide were mixed, vulcanized at 170°C and 12 MPa for 2 min, and molded into a solvent-resistant high-strength sealing rubber.

[0061] Comparative Example 2

[0062] The modified rubber was prepared without adding the amphiphilic copolymer, and the other parameters were the same as those in Comparative Example 2.

[0063] Step 1: Add 5 g of graphene oxide to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, add 20 g of isophorone diisocyanate and continue ultrasonic dispersion for 30 min, and then react at 75 ° C for 30 h; centrifuge, wash, and vacuum dry for 12 h to obtain isocyanate-modified graphene oxide;

[0064] Step 2: dehydrate 1 mol of polyethylene glycol at 120° C. and 0.8 MPa for 2 h, cool to 40° C., add 2 mol of diphenylmethane diisocyanate, mix, and react at 80° C. for 3 h to obtain a polyurethane prepolymer;

[0065] Step 3: 100 kg of natural rubber latex, 22 kg of polyurethane prepolymer, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide are mixed, vulcanized at 170° C. and 12 MPa for 2 min, and molded into a solvent-resistant high-strength sealing rubber.

[0066] Comparative Example 3

[0067] The amount of the macromolecular hydrophobic initiator in step 2 was increased, and the other parameters were the same as those in comparative example 3.

[0068] Step 1: 1 mol of butyl methacrylate, 1 mol of azobisisobutyronitrile and 2 mol of 1,1-diphenylethylene were stirred and mixed, and heated to 72°C in a vacuum environment for reaction for 20 hours. After the reaction was completed, methanol was added for precipitation and chloroform was used for dissolution. The mixture was repeated twice and dried to obtain a macromolecular hydrophobic initiator.

[0069] Step 2: 30% of butene glycol, 15% of a macromolecular hydrophobic initiator, 30% of 2-acrylamido-2-methylpropanesulfonic acid, and 25% of toluene were mixed according to weight percentage, and stirred evenly to obtain a reaction solution, which was heated to 82° C. under a vacuum environment for reaction for 8 hours, and the product was precipitated with acetone, washed with deionized water, and then dried to obtain an amphiphilic copolymer;

[0070] Step 3: Add 5 g of graphene oxide to 500 g of dimethylformamide solvent, and after ultrasonic dispersion for 2 h, add 20 g of isophorone diisocyanate and continue ultrasonic dispersion for 30 min, and then react at 75 ° C for 30 h; centrifuge, wash, and vacuum dry for 12 h to obtain isocyanate-modified graphene oxide;

[0071] Step 4: dehydrate 1 mol of polyethylene glycol at 120°C and 0.8 MPa for 2 h, cool to 40°C, add 2 mol of diphenylmethane diisocyanate and mix, react at 80°C for 3 h to obtain a polyurethane prepolymer; mix 100 kg of natural rubber latex and 18 kg of amphiphilic copolymer, add 0.45 kg of ammonium persulfate, 0.3 kg of sodium thiosulfate and 0.02 kg of N,N'-methylenebisacrylamide, heat to 40°C, react for 3 h, dry, and purify to obtain a modified rubber;

[0072] Step 5: 100 kg of modified rubber, 22 kg of polyurethane prepolymer, 6 kg of isocyanate-modified graphene oxide, 0.5 kg of antioxidant, 1 kg of active zinc oxide, and 1 kg of diisopropylbenzene peroxide are mixed, vulcanized at 170° C. and 12 MPa for 2 min, and molded into a solvent-resistant high-strength sealing rubber.

[0073] experiment

[0074] The water absorption performance (clean water) and tensile strength tests were performed on Examples 1 to 6 and Comparative Examples 1 to 3. After the tests, the samples were immersed in saline with a mineralization degree of 100 g / L for 14 days, removed and dried to constant weight, and the water absorption performance (clean water) retention rate and tensile strength retention rate were tested again. The experimental results are shown in the following table.

[0075] Water absorption rate = (mass after water absorption - mass before water absorption) / mass before water absorption;

[0076] Tensile strength test: According to GB / T1040-92, the rubber was cut into a dumbbell shape (size 4mm×75mm×2mm), placed in an electronic universal testing machine, and subjected to a tensile test at a tensile speed of 100mm / min.

[0077]

[0078] in conclusion:

[0079] The data of Examples 1 to 6 show that the sealing rubber prepared by the present invention has high mechanical strength, strong water absorption performance, and high tolerance to salt solutions, and can be used as a sealing material for operations in most oil fields, groundwater and other high-salt and high-mineralization fields. Comparing the data of Example 1 with that of Comparative Example 1, it is found that the mechanical properties and water absorption capacity of the sealing rubber prepared by directly physically blending polyurethane and natural rubber are inferior to those of Example 1 due to the poor compatibility of polyurethane and rubber. By comparing the data of Example 2 and Comparative Example 2, it is found that in Comparative Example 2, no amphiphilic copolymer is added, and the polyurethane prepolymer and natural rubber are blended and polymerized to prepare the sealing rubber, and the sealing rubber has an interpenetrating polymer network structure, but there is no reactive active site between the polyurethane molecular chain and the natural rubber molecular chain, so the two polymer molecules are cross-linked in physical form; while in Example 2, the amphiphilic copolymer contains hydrophilic and hydrophobic groups, has good compatibility with natural rubber emulsion and polyurethane, and can improve the stability of the reaction body; at the same time, the amphiphilic copolymer contains hydroxyl groups, which can react with the polyurethane prepolymer and isocyanate-modified graphene oxide to further produce chemical crosslinking, so the obtained sealing rubber has better mechanical properties; in addition, the amphiphilic copolymer contains sulfonic acid groups, has strong salt resistance, and can improve the service life of the sealing rubber in salt solution. By comparing the data of Example 3 and Comparative Example 3, it is found that after increasing the amount of macromolecular hydrophobic initiator, the hydrophobicity of the amphiphilic copolymer is enhanced, which ultimately leads to the synthesized sealing rubber having strong hydrophobicity, poor water absorption performance, decreased expansion rate in the solution, and poor sealing effect.

[0080] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for processing solvent-resistant high-strength sealing rubber, characterized in that: The following steps are involved: S1: adding butene glycol, a macromolecular hydrophobic initiator, and 2-acrylamide-2-methylpropanesulfonic acid to toluene, mixing and stirring to obtain a reaction solution, heating in a vacuum, reacting, precipitating, washing, and drying to obtain an amphiphilic copolymer; The preparation method of the macromolecular hydrophobic initiator is as follows: butyl methacrylate, initiator azobisisobutyronitrile, and molecular weight regulator 1,1-diphenylethylene are stirred and mixed, heated to 70-75° C. in a vacuum environment, and reacted for 20-25 hours; The contents of the components in the reaction solution are, by weight percentage, 20-35% of butene glycol, 5-10% of a macromolecular hydrophobic initiator, 20-30% of 2-acrylamido-2-methylpropanesulfonic acid, and 20-50% of toluene; S2: adding graphene oxide to dimethylformamide solvent, and after ultrasonic dispersion, adding isophorone diisocyanate and continuing ultrasonication, reacting, centrifuging, washing, and vacuum drying to obtain isocyanate-modified graphene oxide; S3: dehydrating polyethylene glycol, adding diphenylmethane diisocyanate to mix, and reacting to obtain a polyurethane prepolymer; mixing natural rubber latex and amphiphilic copolymer, adding ammonium persulfate, sodium thiosulfate and N,N'-methylenebisacrylamide, reacting, drying, and purifying to obtain a modified rubber; S4: The modified rubber, the polyurethane prepolymer, the isocyanate-modified graphene oxide, the antioxidant, the active zinc oxide, and the vulcanizing agent are mixed, and the mixture is vulcanized and pressed into a film to obtain a solvent-resistant high-strength sealing rubber.

2. The method for processing a solvent-resistant high-strength sealing rubber according to claim 1, characterized in that: In S1, the reaction temperature of the amphiphilic copolymer is 80-90°C, and the reaction time is 8-10 h.

3. The method for processing a solvent-resistant high-strength sealing rubber according to claim 1, characterized in that: In S2, the reaction temperature of isocyanate-modified graphene oxide is 70-80°C, and the reaction time is 25-30h.

4. The method for processing a solvent-resistant high-strength sealing rubber according to claim 1, characterized in that: In S3, the amounts of the components are, by weight, 100 parts of natural rubber latex, 15-18 parts of amphiphilic copolymer, 0.3-0.5 parts of ammonium persulfate, 0.3-0.5 parts of sodium thiosulfate, and 0.01-0.02 parts of N,N'-methylenebisacrylamide.

5. The method for processing a solvent-resistant high-strength sealing rubber according to claim 1, characterized in that: In S4, the amounts of the components are, by weight, 100 parts of modified rubber, 20-30 parts of polyurethane prepolymer, 4-6 parts of isocyanate-modified graphene oxide, 0.5-1 parts of antioxidant, 1-2 parts of active zinc oxide, and 1-1.2 parts of vulcanizing agent.

6. The method for processing a solvent-resistant high-strength sealing rubber according to claim 1, characterized in that: In S4, the vulcanizing agent is any one of dicumyl peroxide, sulfur, and vulcanizing agent DTDM.

7. The method for processing a solvent-resistant high-strength sealing rubber according to claim 1, characterized in that: In S4, the temperature of the vulcanization treatment is 170~190°C, the pressure is 12~15Mpa, and the time is 2~4min.

8. The rubber prepared by the processing method of a solvent-resistant high-strength sealing rubber according to any one of claims 1 to 7.

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