High-strength and high-toughness rubber and preparation method thereof

Abstract

The invention discloses high-strength and high-toughness rubber and a preparation method thereof, and is applied to the technical field of rubber materials. By adopting a method for hybridizing and crosslinking rubber by adopting multiple crosslinking systems, multiple crosslinking bond networks with different strength are introduced, and when the rubber is stretched, the fragile network as a sacrifice bond reaches the strain limit firstly, and then, the fragile network is taken as a sacrifice bond; the elastic rubber prepared by the method not only can obtain high elasticity, high strength and high toughness, but also has a self-repairing function, the strength and toughness of the rubber are improved, and the service life of the rubber is prolonged. And when the composite material is used for developing a high-performance dynamic cable, the service life of the composite material must be greatly prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber materials, and particularly relates to a high-strength and high-toughness rubber and a preparation method thereof. Background Art

[0002] With the continuous development of science and technology, high-strength and high-toughness elastomers have shown great application potential in many fields, especially in flexible electronics such as electronic skin, wearable electronic devices, and human-machine interfaces. However, in the field of wires and cables, the performance requirements for rubber materials are also increasing, especially in some special occasions, such as coal mining, mining and tunnel engineering machinery and other harsh environments.

[0003] In these special environments, cables need to withstand complex external forces and harsh climatic conditions, which puts higher requirements on the strength and toughness of cable rubber. The traditional method of increasing the strength and modulus of elastomers by adding nanofillers has many problems. On the one hand, while nanofillers increase the strength and modulus, they will reduce the elongation at break of the material, resulting in limited increase in toughness and failure to meet actual needs. On the other hand, nanofillers also have problems such as difficulty in uniform dispersion, poor processing performance, weakened elasticity, and insufficient strength of the final product. Summary of the invention

[0004] The purpose of the present invention is to target an existing high-strength and high-toughness rubber and a preparation method thereof, which has the advantage of adopting a method of hybrid cross-linking the rubber using a variety of cross-linking systems, introducing a multiple cross-linking bond network of varying strengths, and when the rubber is stretched, the fragile network first reaches the strain limit as a sacrificial bond, gradually breaking the bonds to release the hidden length and straightening to dissipate a large amount of energy, thereby significantly improving the strength, modulus, and elongation at break of the rubber, and achieving an enhanced and toughening effect. The elastic rubber prepared by the method can not only obtain high elasticity, high strength, and high toughness, but also has a self-repairing function, thereby improving the strength and toughness of the rubber, and improving its fatigue resistance and service life. Using it to develop high-performance dynamic cables will greatly increase their service life.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: A high-strength and high-toughness rubber, calculated by mass, comprising:

[0006] 100 parts by mass of EPDM rubber, 0.6-0.8 parts by mass of aliphatic ether polysulfide vulcanizing agent, 1.5-2.0 parts by mass of dicumyl peroxide vulcanizing agent, 0.6-0.8 parts by mass of urethane vulcanizing agent, 0.6-1.0 parts by mass of N,N′-phenylene bismaleimide vulcanizing agent, 5-9 parts by mass of nano zinc oxide, 0.5-1.0 parts by mass of stearic acid, 2-3 parts by mass of dibasic lead stearate, 2-3 parts by mass of microcrystalline paraffin, 2-3 parts by mass of WB222 processing aid, 1.5-2.0 parts by mass of antioxidant RD, 1.5-2.0 parts by mass of antioxidant MB, 8-10 parts by mass of No. 500 paraffin oil, 40-50 parts by mass of calcined kaolin, 80-90 parts by mass of ultrafine talc, 35-45 parts by mass of nano calcium carbonate, and 3-5 parts by mass of calcium oxide.

[0007] The present invention is further configured as follows: the EPDM rubber is an EPDM rubber with high ethylene content, high ENB content and low Mooney content, and the model is KEP210.

[0008] By adopting the above technical scheme, EPDM rubber is a terpolymer of ethylene, propylene and a small amount of non-conjugated diene, and its main chain is a fully saturated CC bond, which makes it have excellent insulation, heat aging resistance, moisture resistance and ozone resistance, and its properties can be adjusted by changing the number of three monomers, ethylene propylene ratio, molecular weight and its distribution, and vulcanization method.

[0009] The present invention is further configured as follows: the aliphatic ether polysulfide releases 48%-52% of active sulfur at the vulcanization temperature, and undergoes addition reaction with the non-conjugated diene in the EPDM rubber to generate monosulfide bonds and disulfide bonds.

[0010] By adopting the above technical scheme, aliphatic ether polysulfide is a vulcanizing agent for natural rubber, various synthetic rubbers and rubbers blended therewith: at the vulcanization temperature, 48%-52% active sulfur will be released, which has a highly efficient cross-linking effect on the rubber; aliphatic ether polysulfide reacts with the non-conjugated diene in EPDM rubber by addition reaction; the single sulfur bond and disulfide bond generated by the reaction have low bond energy; as sacrificial bonds, they will be preferentially broken when the rubber is stretched to dissipate energy, thereby improving the strength and toughness of the rubber; in addition, the disulfide bond can self-heal and re-cross-link after breaking, thereby improving the dynamic performance of the rubber.

[0011] The present invention is further configured as follows: the dicumyl peroxide is homolytically cleaved at high temperature to form alkoxy free radicals, which crosslink the polymer chains to form -CC- bonds and initiate the crosslinking reaction of the urethane vulcanizing agent and the bismaleimide vulcanizing agent.

[0012] The above technical scheme is adopted, and diisopropylbenzene peroxide is used as a vulcanizing agent and an initiator. Firstly, diisopropylbenzene peroxide is homolytically split at a high temperature to form two alkoxy free radicals. The alkoxy free radicals capture hydrogen atoms from the molecular chain of EPDM rubber, and two adjacent free radicals combine to form a carbon-carbon (-CC-) bond, reflecting the effect of the vulcanizing agent. Secondly, under the action of the alkoxy free radicals generated by diisopropylbenzene peroxide, a cross-linking reaction of urethane and bismaleimide vulcanizing agents can be initiated.

[0013] The present invention is further configured as follows: the urethane vulcanizing agent reacts with the EPDM rubber under the initiation of dicumyl peroxide to generate -CN- bonds and hydrogen bonds.

[0014] By adopting the above technical scheme, the urethane vulcanizing agent is a stable solid powder at room temperature, and decomposes into p-nitrosophenol and di- or polyisocyanates under vulcanization conditions. Under the action of the initiator diisocyanate, p-nitrosophenol reacts with EPDM rubber to generate aminophenol side groups, which then react with isocyanate to form crosslinks. This crosslinking reaction generates -CN- bonds, and also forms a certain number of hydrogen bonds through -N-. They can all serve as sacrificial bonds, which will break first and dissipate energy when the rubber is stretched, thereby improving the strength and toughness of the rubber. In addition, after the hydrogen bonds are broken, they can self-heal and re-crosslink, thereby improving the dynamic performance of the rubber.

[0015] The present invention is further configured as follows: the N,N′-m-phenylene bismaleimide vulcanizing agent undergoes a crosslinking reaction with the non-conjugated diene in the EPDM rubber to generate -C-bismaleimide-bonds and hydrogen bonds, and also serves as a vulcanizing agent, a vulcanizing agent auxiliary, a scorch retarder and a tackifier.

[0016] By adopting the above technical scheme, N, N'-m-phenylene bismaleimide is a bifunctional multifunctional rubber additive, which can be used as a vulcanizer, a vulcanizing agent additive, a scorch inhibitor and a tackifier. When used as a vulcanizer, due to the action of the carbonyl group, the double bonds of adjacent carbon atoms are broken and cross-linked with the non-conjugated diene in the EPDM rubber to generate -C-bismaleimide-bonds, and at the same time form hydrogen bonds with hydrogen. They can also improve the strength and toughness of rubber. When used as a vulcanizing agent additive, it can improve the heat resistance of rubber, reduce permanent deformation, prevent scorch, and improve the bonding performance

[0017] The present invention is further configured as follows: a multi-component composite parallel system consisting of an aliphatic ether polysulfide vulcanizer, a diisopropylbenzene peroxide vulcanizer, a urethane vulcanizer and an N,N′-phenylene bismaleimide vulcanizer reacts with EPDM rubber to generate six cross-linking bonds including a monosulfide bond, a disulfide bond, a -CN- bond, a hydrogen bond, a -C-bismaleimide bond and a -CC- bond, thereby forming a multiple network system with the five cross-linking bonds including the monosulfide bond, the disulfide bond, the -CN- bond, the hydrogen bond and the -C-bismaleimide bond as sacrificial bonds, thereby greatly improving the strength and toughness of the rubber, and the disulfide bonds and hydrogen bonds can be self-healed and re-cross-linked after being broken, thereby improving the dynamic performance of the rubber.

[0018] A method for preparing high-strength and high-toughness rubber comprises the following steps:

[0019] S1. Preparation of curing agent masterbatch: aliphatic ether polysulfide curing agent, dicumyl peroxide curing agent, urethane, N, N'-phenylene bismaleimide curing agent according to the formula ratio, add 2-4 times the total weight of nano calcium carbonate, stir and mix at a low speed of not more than 60 rpm in a mixer for 10-15 minutes, and then place in a batching barrel for use;

[0020] S2. Mixing: After mixing EPDM rubber in an internal mixer for 1 min, add nano zinc oxide, dibasic lead stearate, calcined kaolin, ultrafine talc, paraffin oil, nano calcium carbonate, antioxidant, microcrystalline wax, WB222 processing aid, mix for 3.0-4.0 min and then discharge the rubber, control the speed at 30-35 rpm, and control the discharge temperature below 145°C;

[0021] S3 Filtration: The kneaded mixture was filtered through a 100-mesh stainless steel filter to remove impurities;

[0022] S4. Sheeting: Use a three-roll calender to roll the filtered rubber into a film with a thickness of 1.2-1.5 mm and store it for 24 hours;

[0023] S5. Vulcanization: After adding the vulcanizing agent masterbatch to the film formed in step S4, secondary mixing is performed, and the mixing time is 0.8-1min;

[0024] S6. Slicing: The rubber compound after the secondary mixing is rolled through a three-roll calender to form rubber strips with a thickness of 0.8-1 mm and a width of 150-160 mm.

[0025] The present invention is further configured as follows: in step S2, the internal mixer is a meshing type internal mixer, the rotor speed of the internal mixer is 30-35r / min, the mixing temperature is 135-145°C, and faster speed and higher temperature mixing are used to remove moisture and small molecular volatiles in the material.

[0026] The present invention is further configured as follows: in step S5, the rotor speed of the internal mixer is 25-30 r / min, the mixing temperature is 100-120° C., and mixing at a slower speed and lower temperature is used to prevent the rubber from being scorched, thereby ensuring the quality of the rubber.

[0027] The present invention is further configured as follows: in step S6, the strip rubber is placed for 24 hours before extrusion molding is performed, so that the additives such as the vulcanizer, activator, accelerator, antioxidant, etc. in the rubber material are evenly dispersed and the stress generated by mixing is eliminated.

[0028] In summary, the present invention has the following beneficial effects:

[0029] 1. By adopting aliphatic ether polysulfide, diisopropylbenzene peroxide, urethane, N,N′-m-phenylene bismaleimide vulcanization system, multiple hybrid crosslinking is achieved, forming six network bonds, including single sulfur bond, disulfide bond, carbon-carbon bond, carbon-nitrogen bond, hydrogen bond, carbon-bismaleimide bond, etc., whose bond lengths and bond energies are different. Except for the carbon-carbon bond, the other five are dynamic sacrificial bonds, which reach the strain limit in different stages of the stretching process, gradually break the bond to release the hidden length and straighten to dissipate a lot of energy, thereby achieving the goal of significantly improving the strength and toughness of the rubber;

[0030] 2. By using aliphatic ether polysulfide to react with non-conjugated diene in EPDM rubber, the single sulfur bond and disulfide bond generated by the reaction have low bond energy, which will be broken first and dissipate energy when the rubber is stretched, thereby improving the strength and toughness of the rubber. At the same time, the disulfide bond is a reversible sacrificial bond with self-healing function. After breaking, it can also self-heal and re-crosslink, thereby improving the dynamic performance of the rubber;

[0031] 3. The urethane curing agent used reacts with EPDM rubber under the initiation of dicumyl peroxide to generate two sacrificial bonds, -CN- bond and hydrogen bond, which not only improves the strength and toughness of the rubber, but also the hydrogen bond is a reversible sacrificial bond with self-healing function. It can also self-heal and re-crosslink after breaking, thus improving the dynamic performance of the rubber;

[0032] 4. The N, N′-m-phenylene bismaleimide used is a bifunctional multifunctional rubber additive, which can also serve as a vulcanizer, a vulcanizing agent additive, a scorch inhibitor and a tackifier. When used as a vulcanizer, due to the carbonyl effect, the double bonds of adjacent carbon atoms are broken and cross-linked with the non-conjugated diene in the EPDM rubber to generate -C-bismaleimide-bonds and hydrogen bonds, which can also improve the strength and toughness of the rubber. As a vulcanizing agent additive, it can improve the heat resistance of the rubber, reduce permanent deformation, prevent scorch, and improve the bonding performance;

[0033] 5. By adopting the aliphatic ether polysulfide, urethane, N, N'-phenylene bismaleimide vulcanization system, the disulfide bonds generated by the aliphatic ether polysulfide and the hydrogen bonds generated by urethane and N, N'-phenylene bismaleimide are reversible sacrificial bonds, which have the function of self-healing and re-crosslinking after the bond is broken, which greatly improves the dynamic resistance of the rubber; BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a preparation process diagram of the preparation method of the high-strength and high-toughness rubber of the present invention. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0036] In order to further illustrate the present invention, a high-strength and high-toughness rubber provided by the present invention is described in detail in combination with the embodiments below. However, it should be understood that these embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following embodiments.

[0037] The raw materials in the following examples are all commercially available products.

[0038] The selection includes: 100 parts by mass of EPDM rubber, 0.6-0.8 parts by mass of aliphatic ether polysulfide vulcanizer, 1.5-2.0 parts by mass of diisopropyl peroxide vulcanizer, 0.6-0.8 parts by mass of urethane vulcanizer, 0.6-1.0 parts by mass of N,N′-phenylene bismaleimide vulcanizer, 5-9 parts by mass of nano zinc oxide, 0.5-1.0 parts by mass of stearic acid, 2-3 parts by mass of dibasic lead stearate, 2-3 parts by mass of microcrystalline paraffin, 2-3 parts by mass of WB222 processing aid, 1.5-2.0 parts by mass of antioxidant RD, 1.5-2.0 parts by mass of antioxidant MB, 8-10 parts by mass of No. 500 paraffin oil, 40-50 parts by mass of calcined kaolin, 80-90 parts by mass of ultrafine talc, 35-45 parts by mass of nano calcium carbonate, and 3-5 parts by mass of calcium oxide.

[0039] Example 1

[0040] Select 1000g of EPDM rubber, 6g of aliphatic ether polysulfide vulcanizer, 18g of diisopropylbenzene peroxide, 7g of urethane, 6g of N,N′-phenylene bismaleimide vulcanizer, 50g of nano zinc oxide, 6g of stearic acid, 30g of dibasic lead stearate, 20g of microcrystalline paraffin, 20g of WB222 processing aid, 15g of antioxidant RD, 15g of antioxidant MB, 80g of No. 500 paraffin oil, 400g of calcined kaolin, 800g of ultrafine talc, 350g of nano calcium carbonate, and 30g of calcium oxide.

[0041] First, 6g of aliphatic ether polysulfide vulcanizer, 18g of diisopropylbenzene peroxide, 7g of urethane, 6g of N,N′-phenylene bismaleimide vulcanizer and 2.5 times of nano calcium carbonate were mixed for 10 minutes to prepare a masterbatch; after mixing EPDM rubber in an internal mixer for 1 minute, nano zinc oxide, dibasic lead stearate, calcined kaolin, ultrafine talcum powder, paraffin oil, nano calcium carbonate, antioxidant, microcrystalline wax, WB222 processing aid were added, and the glue was discharged after mixing for 3.0-4.0 minutes, the speed was controlled at 30-35 rpm, and the discharge temperature was controlled at Below 145℃, pay attention to observe the temperature of the mixing chamber of the internal mixer during mixing to ensure the mixing quality of the mixed rubber; filter the mixed mixture with a 100-mesh stainless steel filter to remove impurities; use a three-roll calender to roll the filtered rubber into a film with a thickness of 1.2-1.5mm, store it for 24 hours, and then add the vulcanizer masterbatch to the film, and then carry out secondary mixing with a mixing time of 0.8-1min, and then roll the rubber after the secondary mixing through a three-roll calender to form a strip rubber with a thickness of 0.8-1mm and a width of 150-160mm.

[0042] Experiments show that the EPDM rubber prepared by the present invention has a tensile strength TB = 13.6 MPa, a breaking elongation EB = 785%, and a fracture toughness K IC =26.8KJ / m 2 , rubber has excellent strength and toughness.

[0043] Example 2

[0044] Select 1000g of EPDM rubber, 7g of aliphatic ether polysulfide vulcanizer, 19g of diisopropylbenzene peroxide, 8g of urethane, 7g of N,N′-phenylene bismaleimide vulcanizer, 60g of nano zinc oxide, 7g of stearic acid, 25g of dibasic lead stearate, 25g of microcrystalline paraffin, 25g of WB222 processing aid, 18g of antioxidant RD, 18g of antioxidant MB, 90g of No. 500 paraffin oil, 450g of calcined kaolin, 850g of ultrafine talc, 400g of nano calcium carbonate, and 40g of calcium oxide.

[0045] First, 7g of aliphatic ether polysulfide vulcanizer, 19g of diisopropylbenzene peroxide, 8g of urethane, 7g of N,N′-phenylene bismaleimide vulcanizer and 3 times of nano calcium carbonate were mixed for 10 minutes to prepare a masterbatch; after mixing EPDM rubber in an internal mixer for 1 minute, nano zinc oxide, dibasic lead stearate, calcined kaolin, ultrafine talcum powder, paraffin oil, nano calcium carbonate, antioxidant, microcrystalline wax, WB222 processing aid were added, and the mixture was mixed for 3.0-4.0 minutes before the glue was discharged, the speed was controlled at 30-35 rpm, and the glue discharge temperature was controlled at 1 Below 45℃, pay attention to observe the temperature of the mixing chamber of the internal mixer during mixing to ensure the mixing quality of the mixed rubber; filter the mixed mixture with a 100-mesh stainless steel filter to remove impurities; use a three-roll calender to roll the filtered rubber into a film with a thickness of 1.2-1.5mm, store it for 24 hours, and then add the vulcanizer masterbatch to the film, and then carry out secondary mixing with a mixing time of 0.8-1min, and then roll the rubber after the secondary mixing through a three-roll calender to form a strip rubber with a thickness of 0.8-1mm and a width of 150-160mm.

[0046] Experiments show that the EPDM rubber prepared by the present invention has a tensile strength TB = 14.0 MPa, a breaking elongation EB = 792%, and a fracture toughness K IC =28.8KJ / m 2 , rubber has excellent strength and toughness.

[0047] Example 3

[0048] Select 1000g of EPDM rubber, 8g of aliphatic ether polysulfide vulcanizer, 20g of diisopropylbenzene peroxide, 10g of urethane, 8g of N,N′-phenylene bismaleimide vulcanizer, 80g of nano zinc oxide, 8g of stearic acid, 30g of dibasic lead stearate, 30g of microcrystalline paraffin, 28g of WB222 processing aid, 20g of antioxidant RD, 20g of antioxidant MB, 100g of No. 500 paraffin oil, 500g of calcined kaolin, 900g of ultrafine talc, 450g of nano calcium carbonate, and 50g of calcium oxide.

[0049] First, 7g of aliphatic ether polysulfide vulcanizer, 19g of diisopropylbenzene peroxide, 8g of urethane, 7g of N,N′-phenylene bismaleimide vulcanizer and 4 times of nano calcium were mixed for 10 minutes to prepare a masterbatch; after mixing EPDM rubber in an internal mixer for 1 minute, nano zinc oxide, dibasic lead stearate, calcined kaolin, ultrafine talcum powder, paraffin oil, nano calcium carbonate, antioxidant, microcrystalline wax, WB222 processing aid were added, and the glue was discharged after mixing for 3.0-4.0 minutes, and the speed was controlled at 30-35 rpm and the discharge temperature was controlled at 14 Below 5℃, pay attention to observe the temperature of the mixing chamber of the internal mixer during mixing to ensure the mixing quality of the mixed rubber; filter the mixed mixture with a 100-mesh stainless steel filter to remove impurities; use a three-roll calender to roll the filtered rubber into a film with a thickness of 1.2-1.5mm, store it for 24 hours, and then add the vulcanizer masterbatch to the film, and then carry out secondary mixing with a mixing time of 0.8-1min, and then roll the rubber after the secondary mixing through a three-roll calender to form a strip rubber with a thickness of 0.8-1mm and a width of 150-160mm.

[0050] Experiments show that the EPDM rubber prepared by the present invention has a tensile strength TB = 14.1 MPa, a breaking elongation EB = 805%, and a fracture toughness K IC =30.2KJ / m 2 , rubber has excellent strength and toughness.

[0051] In order to further improve the quality of a high-strength and high-toughness rubber and refine the rubber formula, while better ensuring the service life of the cable, the embodiment of the present invention also provides a preparation method as any one of the above technical solutions, comprising the following steps:

[0052] Step S1. Preparation of vulcanizing agent masterbatch: weigh the vulcanizing agent aliphatic ether polysulfide vulcanizing agent, diisopropylbenzene peroxide, urethane, and N,N′-phenylene bismaleimide vulcanizing agent according to the formula ratio, add them to 2-4 times the total weight of nano calcium carbonate, stir and mix them at a low speed of not more than 60 rpm in a mixer for 10-15 minutes, and then put them in a batching barrel for preparation.

[0053] In the above preparation method of the present invention, the weight ratio of nano calcium carbonate is preferably 2-4 times the total weight of the four vulcanizing agents, and the mixing time is preferably 2-4 times, 10-15 min; the weight ratio of nano calcium carbonate is more preferably 2.5-3.5 times, and the mixing time is preferably 11-14 min; the weight ratio of nano calcium carbonate is more preferably 2-3 times, 12-13 min.

[0054] Step S2. Mixing: After mixing the EPDM rubber in an internal mixer for 1 minute, add nano zinc oxide, dibasic lead stearate, calcined kaolin, ultrafine talc, paraffin oil, nano calcium carbonate, antioxidant, microcrystalline paraffin, WB222 processing aid, mix for 3.0-4.0 minutes and then discharge the rubber. The speed is controlled at 30-35 rpm and the discharge temperature is controlled below 145°C. During mixing, pay attention to the temperature of the mixing chamber of the internal mixer to ensure the mixing quality of the mixed rubber.

[0055] In the above preparation method of the present invention, the binder is discharged after mixing for 3.0-4.0 minutes, and the discharge temperature is controlled below 145°C. More preferably, the mixing time is 3.5-4.0 minutes, the rotation speed is controlled at 32-34 rpm, and the discharge temperature is 135-140°C.

[0056] Step S3. Filtration: The kneaded mixture is filtered through a 100-mesh stainless steel filter to remove impurities.

[0057] Step S4. Sheeting: The filtered rubber material is rolled into a sheet with a thickness of 1.2-1.5 mm using a three-roll calender and stored for 24 hours.

[0058] The rolling thickness of the present invention is preferably 1.2-1.5 mm, more preferably 1.3-1.4 mm.

[0059] Step S5. Adding vulcanizing agent: After adding the vulcanizing agent masterbatch to the film formed in step S4, secondary mixing is performed, and the mixing time is 0.8-1 min.

[0060] In the present invention, the mixing time in the above step S5 is preferably 0.8-1.0 min, more preferably 0.9-1.0 min, and more preferably 0.8-0.9 min.

[0061] Step S6. Slicing: The rubber material after the secondary mixing is rolled through a three-roll calender to form rubber strips with a thickness of 0.8-1 mm and a width of 150-160 mm.

[0062] The width of the present invention is preferably 150-160 mm, more preferably 155-160 mm, and more preferably 152-158 mm.

[0063] In step S2, the internal mixer adopts an intermeshing type internal mixer for mixing, the rotor speed of the internal mixer is 30-35r / min, the mixing temperature is 135-145°C, and faster speed and higher temperature are used for mixing to remove moisture and small molecular volatiles in the material.

[0064] In step S5, the rotor speed of the internal mixer is 25-30r / min, and the mixing temperature is 100-120°C. A slower speed and lower temperature are used to prevent the rubber from scorching and ensure the quality of the rubber. By setting the basic parameters of the internal mixer, the mixing and mixing of the raw materials are guaranteed, and the quality of rubber production is guaranteed.

[0065] The strip rubber formed in step S6 can be used for extrusion molding only after being left for 24 hours; by leaving it for a long time, on the one hand, the vulcanizer, activator, accelerator, antioxidant and other additives in the rubber material will be further evenly dispersed, and on the other hand, the stress generated by the mixing process will be eliminated, which is beneficial to the molding process and performance improvement; by leaving the rubber for a period of time before extruding it, the vulcanization of the rubber is further guaranteed, and the performance of the rubber is guaranteed.

[0066] The above steps of the present invention provide a method for preparing a high-strength and high-toughness rubber. The present invention adopts EPDM rubber with high ethylene, high ENB content and low Mooney viscosity, and introduces five sacrificial bonds of varying strengths by using four crosslinking systems including aliphatic ether polysulfide vulcanizing agent, diisopropylbenzene peroxide, urethane and N,N′-phenylene bismaleimide vulcanizing agent to hybridize and crosslink the rubber. When the rubber is stretched, the fragile network as a sacrificial bond first reaches the strain limit, gradually breaks the bond to release the hidden length and straightens to dissipate a large amount of energy, thereby significantly improving the strength, modulus and elongation at break of the rubber, and achieving the strengthening and toughening effect. The elastic rubber prepared by the method can not only obtain high elasticity, high strength and high toughness, but also has a self-repairing function. The elastic rubber prepared by the method can not only be used in cables, but can also be further expanded to other fields, and has good practical value and application prospects. In addition, the preparation method provided by the present invention is simple and easy to obtain, and the conditions are mild, which is suitable for industrial large-scale production.

[0067] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A high-strength and high-toughness rubber, characterized in that: Calculated by mass, including: 100 parts by mass of EPDM rubber, 0.6-0.8 parts by mass of aliphatic ether polysulfide vulcanizing agent, 1.5-2.0 parts by mass of dicumyl peroxide vulcanizing agent, 0.6-0.8 parts by mass of urethane vulcanizing agent, 0.6-1.0 parts by mass of N,N′-phenylene bismaleimide vulcanizing agent, 5-9 parts by mass of nano zinc oxide, 0.5-1.0 parts by mass of stearic acid, 2-3 parts by mass of dibasic lead stearate, 2-3 parts by mass of microcrystalline paraffin, 2-3 parts by mass of WB222 processing aid, 1.5-2.0 parts by mass of antioxidant RD, 1.5-2.0 parts by mass of antioxidant MB, 8-10 parts by mass of No. 500 paraffin oil, 40-50 parts by mass of calcined kaolin, 80-90 parts by mass of ultrafine talc, 35-45 parts by mass of nano calcium carbonate, and 3-5 parts by mass of calcium oxide.

2. The high-strength and high-toughness rubber according to claim 1, characterized in that: The EPDM rubber is high-ethylene, high-ENB content, low-Mooney EPDM rubber, model KEP210.

3. The high-strength and high-toughness rubber according to claim 1, characterized in that: The aliphatic ether polysulfide releases 48%-52% of active sulfur at the vulcanization temperature, and reacts with the non-conjugated diene in the EPDM rubber to generate monosulfide bonds and disulfide bonds.

4. The high-strength and high-toughness rubber according to claim 1, characterized in that: The dicumyl peroxide is homolytically cleaved at high temperature to form alkoxy free radicals, which crosslink the polymer chains to form -CC- bonds and initiate the crosslinking reaction of the urethane vulcanizing agent and the bismaleimide vulcanizing agent.

5. The high-strength and high-toughness rubber according to claim 1, characterized in that: The urethane curing agent reacts with the EPDM rubber under the initiation of dicumyl peroxide to generate -CN- bonds and hydrogen bonds.

6. The high-strength and high-toughness rubber according to claim 1, characterized in that: The N,N'-m-phenylene bismaleimide vulcanizing agent undergoes a crosslinking reaction with the non-conjugated diene in the EPDM rubber to generate -C-bismaleimide-bonds and hydrogen bonds, and also serves as a vulcanizing agent, a vulcanizing agent auxiliary, a scorch retarder and a tackifier.

7. The high-strength and high-toughness rubber according to claim 1, wherein a multi-component composite parallel system consisting of an aliphatic ether polysulfide vulcanizer, a diisopropylbenzene peroxide vulcanizer, a urethane vulcanizer and an N,N′-phenylene bismaleimide vulcanizer reacts with EPDM rubber to generate six cross-linking bonds including a monosulfide bond, a disulfide bond, a -CN- bond, a hydrogen bond, a -C-bismaleimide bond and a -CC- bond, thereby forming a multiple network system with the five cross-linking bonds including a monosulfide bond, a disulfide bond, a -CN- bond, a hydrogen bond and a -C-bismaleimide bond as sacrificial bonds, thereby greatly improving the strength and toughness of the rubber, and the disulfide bonds and hydrogen bonds can self-heal and re-cross-link after being broken, thereby improving the dynamic performance of the rubber.

8. A method for preparing a high-strength and high-toughness rubber according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Preparation of curing agent masterbatch: aliphatic ether polysulfide curing agent, dicumyl peroxide curing agent, urethane, N, N'-phenylene bismaleimide curing agent according to the formula ratio, add 2-4 times the total weight of nano calcium carbonate, stir and mix at a low speed of not more than 60 rpm in a mixer for 10-15 minutes, and then place in a batching barrel for use; S2. Mixing: After mixing EPDM rubber in an internal mixer for 1 min, add nano zinc oxide, dibasic lead stearate, calcined kaolin, ultrafine talc, paraffin oil, nano calcium carbonate, antioxidant, microcrystalline wax, WB222 processing aid, mix for 3.0-4.0 min and then discharge the rubber, control the speed at 30-35 rpm, and control the discharge temperature below 145°C; S3 Filtration: The kneaded mixture was filtered through a 100-mesh stainless steel filter to remove impurities; S4. Sheeting: Use a three-roll calender to roll the filtered rubber into a film with a thickness of 1.2-1.5 mm and store it for 24 hours; S5. Vulcanization: After adding the vulcanizing agent masterbatch to the film formed in step S4, secondary mixing is performed, and the mixing time is 0.8-1min; S6. Slicing: The rubber compound after the secondary mixing is rolled through a three-roll calender to form rubber strips with a thickness of 0.8-1 mm and a width of 150-160 mm.

9. The method for preparing a high-strength and high-toughness rubber according to claim 8, characterized in that: In step S2, the internal mixer is an intermeshing type internal mixer, the rotor speed of the internal mixer is 30-35r / min, and the mixing temperature is 135-145°C. A faster speed and higher temperature mixing are used to remove moisture and small molecular volatiles in the material.

10. The method for preparing a high-strength and high-toughness rubber according to claim 8, characterized in that: In step S5, the rotor speed of the internal mixer is 25-30 r / min, and the mixing temperature is 100-120° C. The mixing is carried out at a slower speed and a lower temperature to prevent the rubber from being scorched and ensure the quality of the rubber.

11. The method for preparing a high-strength and high-toughness rubber according to claim 8, characterized in that: In step S6, the strip rubber is left for 24 hours before extrusion molding, so that the vulcanizer, activator, accelerator, antioxidant and other additives in the rubber material are evenly dispersed and the stress generated by mixing is eliminated.

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