Ultrahigh molecular weight polyethylene-nitrile rubber composite elastic material and preparation method thereof

Abstract

The invention discloses an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material which comprises 70-95 wt% of ultra-high molecular weight polyethylene and 5-30 wt% of nitrile rubber powder. An island structure is provided; wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the dispersed phase and the continuous phase are connected through a C-C chemical bond; the particle size of the nitrile rubber powder is less than or equal to 0.7 mm. By limiting the content of the ultra-high molecular weight polyethylene and the nitrile rubber powder, combining the connection between the two phases through a C-C chemical bond and limiting the particle size of the nitrile rubber powder, when the composite elastic material is subjected to external force, rubber particles in the composite elastic material deform firstly, and when the composite elastic material is subjected to small strain, the composite elastic material has good elasticity. And the rubber has good rebound resilience, namely lower permanent deformation.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material and a preparation method thereof. Background Art

[0002] Ultra-high molecular weight polyethylene (UHMW-PE) has excellent strength and modulus compared to other engineering plastics, but its elasticity is poor. Nitrile rubber (NBR) has excellent oil resistance, high wear resistance, good heat resistance, and strong adhesion, but its disadvantage is low strength and modulus.

[0003] In order to solve the problem that the strength and modulus of traditional nitrile rubber are low and the elasticity of ultra-high molecular weight polyethylene is extremely poor, most of the prior art prepares a composite material by combining ultra-high molecular weight polyethylene with nitrile rubber and other auxiliary materials, but there are two problems when nitrile rubber is directly blended with ultra-high molecular weight polyethylene. The first is that the polar nitrile rubber is not compatible with the non-polar ultra-high molecular weight polyethylene, and the performance is not good enough when directly blended; the second is that the prior art mixes the blocky nitrile rubber and ultra-high molecular weight polyethylene in an internal mixer, but because the ultra-high molecular weight polyethylene has a high melting point and is even difficult to melt, this mixing process is difficult to carry out or the mixing uniformity is difficult to ensure. Therefore, in the existing composite materials of ultra-high molecular weight polyethylene and nitrile rubber, ultra-high molecular weight polyethylene and nitrile rubber do not play their respective advantages, and the overall performance is poor.

[0004] For example, Chinese patent document CN113321858A discloses a high-strength and high-wear-resistant rubber composite material, a preparation method and its application in shield machine seals. In parts by weight, the raw material components for preparing the rubber composite material include 100 parts of nitrile rubber, 6 to 12 parts of ultra-high molecular weight polyethylene, 3 to 15 parts of molybdenite, 0.4 to 2 parts of coupling agent, 50 to 120 parts of carbon black, 1 to 5 parts of nano zinc oxide, 2 to 5 parts of antioxidant, 0.5 to 2 parts of accelerator, 1 to 5 parts of softener, 0.5 to 2 parts of vulcanizer and 0.1 to 1 part of anti-scorch agent. The rubber composite material has the characteristics of high strength and high wear resistance.

[0005] Chinese patent document CN106947135A discloses a polyethylene bearing with high load-bearing performance, which belongs to the technical field of mechanical parts and accessories, and is composed of ultra-high molecular weight polyethylene, nitrile rubber, self-lubricant, zinc oxide, stearic acid, cross-linking agent, antioxidant, EVA modified resin, di-sec-octyl phthalate, zinc oxide, foaming agent, lead stearate, carbon fiber and nano-graphite powder. While maintaining the advantages of ultra-high molecular weight polyethylene self-lubricity and wear resistance, the scheme further improves its wear resistance by introducing self-lubricant; by introducing rubber components, while improving its water lubrication friction performance, it also improves the flexibility, impact resistance and vibration reduction of the material; and from the friction coefficient test experimental results, it can be seen that the water lubrication friction coefficient of the ultra-high molecular weight polyethylene composite material is much smaller than that of ultra-high molecular weight polyethylene, and is suitable for use as a water-lubricated bearing material.

[0006] Chinese patent document CN104292590A discloses a halogen-free, non-toxic and environmentally friendly nozzle, which is composed of the following raw materials in parts by weight: 90-100 parts of ultra-high molecular weight polyethylene, 1-2 parts of diphenyl phosphoazide, 2-3 parts of cyclohexane hexol, 0.8-1 parts of dimethylformamide, 3-5 parts of bone char, 0.4-1 parts of decabromodiphenylethane, 0.1-0.2 parts of vinyl acetate, 1-2 parts of sodium oleate, 10-12 parts of attapulgite, 2-3 parts of hydrated zinc borate, 2-3 parts of calcium aluminate, 1-2 parts of 2-bromo-4-methylphenol, 1-2 parts of methyl cellulose, and 5-7 parts of high-resistance additives. The high-resistance additives added in the present invention include: esterified butyral has good softness and flexibility, and emulsified glue can promote the compatibility between materials and improve the fluidity of the melt; and the methyl methacrylate-butadiene-styrene terpolymer is softened and blended with the esterified butyral and the emulsified glue to greatly improve the surface resistance of the finished product.

[0007] Chinese patent document CN1305955C discloses a butadiene rubber-low-density polyethylene crosslinked product, characterized in that it is composed of the following components: butadiene rubber in a mass ratio of 50-80, low-density polyethylene in a mass ratio of 20-50, inorganic rigid particles in a mass ratio of 0-10, and peroxide initiator in a mass ratio of 0.1-1; the raw rubber Mooney viscosity ML (1+4) of the butadiene rubber at 100°C is between 38 and 45; the low-density polyethylene is a long-chain branched polyethylene produced by a high-pressure gas phase method, with a density between 0.919 and 0.923 g / cm3 and a melt index MI between 1.8 and 3.2 g / 10 minutes.

[0008] Chinese patent document CN100509946C discloses a composition comprising an elastomer and a high molecular weight polyethylene having an irregular particle shape, and a preparation method and use thereof, wherein the composition comprises at least one elastomer matrix and at least one other phase having high and / or ultra-high molecular weight polyethylene particles having an irregular shape, wherein the high and / or ultra-high molecular weight polyethylene particles having an irregular shape have a porous structure and a bulk density of less than 0.35 g / cm 3 The elastomer matrix may be selected from nitrile rubber or carboxyl-containing nitrile rubber, etc. Summary of the invention

[0009] In view of the problems existing in the prior art and the directions for improvement, the present invention provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material to solve the problems of low strength and modulus of traditional nitrile rubber, extremely poor elasticity of ultra-high molecular weight polyethylene, and poor overall effect of existing composite materials composed of ultra-high molecular weight polyethylene and nitrile rubber.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] An ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, comprising 70wt%-95wt% of ultra-high molecular weight polyethylene and 5wt%-30wt% of nitrile rubber powder; and having an island structure;

[0012] The nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the dispersed phase and the continuous phase are connected by a CC chemical bond; the particle size of the nitrile rubber powder is ≤0.7 mm.

[0013] The ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention has a modulus of ultra-high molecular weight polyethylene that is much greater than that of nitrile rubber. Therefore, by limiting the contents of ultra-high molecular weight polyethylene and nitrile rubber powder, when the composite elastic material is finally obtained and subjected to external force, the rubber particles in the composite elastic material are deformed first, so that the composite elastic material has good resilience under smaller strain, that is, has lower permanent deformation.

[0014] Optionally, in the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the ultra-high molecular weight polyethylene has a number average molecular weight of 1.5-10 million and is in powder form.

[0015] Optionally, in the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material also includes sulfur, an accelerator, zinc oxide and stearic acid; wherein the amounts of sulfur, accelerator, zinc oxide and stearic acid are not specifically limited and can be adjusted according to actual needs. For example, based on 100 parts by weight of nitrile rubber powder, 0.3-2 parts by weight of sulfur, 0.3-2.5 parts by weight of accelerator, 1-4 parts by weight of zinc oxide and 0.5-2 parts by weight of stearic acid can be added.

[0016] The present invention also provides a method for preparing the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, comprising the following steps:

[0017] The ultra-high molecular weight polyethylene, nitrile rubber powder and a cross-linking agent are uniformly mixed, and then pressed into shape, and then cross-linked and cooled to obtain the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material;

[0018] Wherein, the temperature of the compression molding step is greater than the softening temperature of the ultra-high molecular weight polyethylene and less than the decomposition temperature of the cross-linking agent;

[0019] The cross-linking temperature is greater than the decomposition temperature of the cross-linking agent, and neither the nitrile rubber powder nor the ultra-high molecular weight polyethylene is degraded.

[0020] During the compression molding process of the preparation method, the ultra-high molecular weight polyethylene melts or softens, so that the ultra-high molecular weight polyethylene is interconnected and combined under surface tension to form a continuous phase, while the nitrile rubber powder does not melt and retains the original phase to form a dispersed phase. During the cross-linking process, the CC chemical bond between the nitrile rubber powder and the ultra-high molecular weight polyethylene phase can be achieved through the decomposition of the cross-linking agent.

[0021] Optionally, in the method for preparing the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the cross-linking step is carried out under normal pressure, that is, after compression molding, the pressure is released to normal pressure, and then cross-linking is carried out.

[0022] Optionally, in the method for preparing the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the amount of the cross-linking agent used is 0.1wt%-4wt% of the total amount of the ultra-high molecular weight polyethylene and the nitrile rubber powder.

[0023] Optionally, in the method for preparing the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the cross-linking agent is a peroxide cross-linking agent, preferably DCP (dicumyl peroxide).

[0024] Optionally, in the preparation method of the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the temperature of the compression molding is 110-140° C. The specific molding pressure depends on the molding equipment, which is generally greater than or equal to 10T; the specific molding time is determined according to the molding pressure and molding temperature to ensure that the mold used for molding is well filled, which is generally 1-60min.

[0025] Optionally, in the preparation method of the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the cross-linking temperature is 140-200° C. The specific cross-linking time is determined by the amount of the cross-linking agent and the cross-linking temperature to ensure that the cross-linking is completed, generally 1-60 minutes.

[0026] Optionally, the preparation method of the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention also includes the step of mixing sulphur, accelerator, zinc oxide and stearic acid with the ultra-high molecular weight polyethylene, the nitrile rubber powder and the cross-linking agent. The purpose of adding sulphur, accelerator, zinc oxide and stearic acid is to improve the cross-linking degree of the nitrile rubber itself.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. In the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the particle size of the dispersed phase is determined by the particle size of the nitrile rubber powder, which is very easy to control. At the same time, the dispersed phase composed of the nitrile rubber powder and the continuous phase composed of the ultra-high molecular weight polyethylene are connected by a CC bond. Therefore, the thermal fluidity of the composite elastic material is not high and the heat resistance is very good.

[0029] 2. The ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention has nitrile rubber particles with good elasticity inside, so that the composite elastic material has better elasticity than polyethylene when subjected to extrusion, stretching and shearing, and can produce elastic deformation similar to rubber, showing lower permanent deformation; at the same time, combined with the limitation that the content of nitrile rubber powder does not exceed 30%, it effectively avoids excessive nitrile rubber powder from forming a continuous phase locally, resulting in a significant decrease in the strength of the material.

[0030] 3. In the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the dispersed phase and the continuous phase are connected by a CC bond, so that the two phases have a very high interface strength. When the material is stretched, the ultra-high molecular weight polyethylene phase and the nitrile rubber phase are not easily separated, so that the nitrile rubber particles will not become stress concentration points, and the high modulus and high strength characteristics of the ultra-high molecular weight polyethylene will not be destroyed.

[0031] 4. In the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, the nitrile rubber in the ultra-high molecular weight polyethylene will be cross-linked by the cross-linking agent DCP, so that it has good elasticity, and the composite elastic material has a high elastic modulus.

[0032] 5. In the preparation method of the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention, by using nitrile rubber powder with a smaller particle size, good blending with ultra-high molecular weight polyethylene and cross-linking agent DCP can be achieved, so that the composite elastic material has good dispersibility, elasticity and strength. By molding at a temperature greater than the softening temperature of ultra-high molecular weight polyethylene and less than the decomposition temperature of the cross-linking agent, taking the cross-linking agent DCP as an example, since the half-life of DCP at 130°C is about 2.2h, molding at a temperature below 130°C ensures that DCP does not decompose or decomposes very little during the molding process, so that no cross-linking reaction occurs in the system, the system has good fluidity, and the rubber particles can be more evenly dispersed in the ultra-high molecular weight polyethylene of the continuous phase, and the prepared composite material has better strength and elasticity; after the combination molding, the cross-linking reaction is carried out at normal pressure, which effectively avoids excessive stress in the material, so that after the cross-linking reaction, the stress in the material is basically eliminated, the material has high dimensional stability, good toughness, and good elongation. DETAILED DESCRIPTION

[0033] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0034] If no specific experimental steps or conditions are specified in the examples and comparative examples, the conventional experimental steps or conditions described in the literature in the art can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be purchased commercially.

[0035] Example 1

[0036] This embodiment provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 80wt% of ultra-high molecular weight polyethylene with a molecular weight of 2 million and 20% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0037] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0038] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 2 million, frozen and crushed powdered nitrile rubber with a particle size of 0.6 mm, and peroxide DCP are uniformly mixed by high-speed mixing to obtain a mixture;

[0039] The amount of DCP is 1wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0040] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 120° C. and a pressure of 40T, the compression molding time being 30 minutes.

[0041] 3) After releasing the pressure, the mixture formed by compression molding in step 2) together with the mold is heated to 160° C. and kept warm for 10 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0042] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0043] Comparative Example 1-1

[0044] This comparative example provides an ultra-high molecular weight polyethylene material, and the specific preparation method is as follows:

[0045] 1) uniformly mixing ultra-high molecular weight polyethylene with a number average molecular weight of 2,000,000 and peroxide DCP by high-speed mixing to obtain a mixture;

[0046] The amount of DCP is 1wt% of the mass of ultra-high molecular weight polyethylene;

[0047] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 120° C. and a pressure of 40T, the compression molding time being 30 minutes.

[0048] 3) After releasing the pressure, the mixture formed in step 2) together with the mold is heated to 160° C. on a flat vulcanizing press and kept at this temperature for 10 minutes;

[0049] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0050] Comparative Example 1-2

[0051] The comparative example provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 80wt% of ultra-high molecular weight polyethylene with a molecular weight of 2 million and 20% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0052] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0053] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 2 million, frozen and crushed powdered nitrile rubber with a particle size of 1 mm, and peroxide DCP are uniformly mixed by high-speed mixing to obtain a mixture;

[0054] The amount of DCP is 1wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0055] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 120° C. and a pressure of 40T, the compression molding time being 30 minutes.

[0056] 3) After releasing the pressure, the mixture formed by compression molding in step 2) together with the mold is heated to 160° C. and kept warm for 10 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0057] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0058] Comparative Examples 1-3

[0059] The comparative example provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 60wt% of ultra-high molecular weight polyethylene with a molecular weight of 2 million and 40% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0060] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0061] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 2 million, frozen and crushed powdered nitrile rubber with a particle size of 1 mm, and peroxide DCP are uniformly mixed by high-speed mixing to obtain a mixture;

[0062] The amount of DCP is 1wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0063] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 120° C. and a pressure of 40T, the compression molding time being 30 minutes.

[0064] 3) After releasing the pressure, the mixture formed by compression molding in step 2) together with the mold is heated to 160° C. and kept warm for 10 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0065] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0066] Comparative Examples 1-4

[0067] The comparative example provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 80wt% of ultra-high molecular weight polyethylene with a molecular weight of 2 million and 20% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0068] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0069] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 2,000,000 and frozen and crushed powdered nitrile rubber with a particle size of 0.6 mm are uniformly mixed by high-speed mixing to obtain a mixture;

[0070] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 120° C. and a pressure of 40T, the compression molding time being 30 minutes.

[0071] 3) After releasing the pressure, the mixture formed in step 2) together with the mold is heated to 160° C. on a flat vulcanizing press and kept at this temperature for 10 minutes;

[0072] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0073] Comparative Examples 1-5

[0074] The comparative example provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 80wt% of ultra-high molecular weight polyethylene with a molecular weight of 2 million and 20% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0075] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0076] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 2 million, frozen and crushed powdered nitrile rubber with a particle size of 0.6 mm, and peroxide DCP are uniformly mixed by high-speed mixing to obtain a mixture;

[0077] The amount of DCP is 1wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0078] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 150° C. and a pressure of 40T, the compression molding time being 30 minutes.

[0079] 3) After releasing the pressure, the mixture formed by compression molding in step 2) together with the mold is heated to 160° C. and kept warm for 10 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0080] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0081] Example 2

[0082] This embodiment provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 70wt% of ultra-high molecular weight polyethylene with a molecular weight of 2 million and 30% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0083] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0084] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 2 million, frozen and crushed powdered nitrile rubber with a particle size of 0.7 mm, and peroxide DCP are uniformly mixed by high-speed mixing to obtain a mixture;

[0085] The amount of DCP is 4wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0086] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 110° C. and a pressure of 30T, the compression molding time being 40 minutes.

[0087] 3) After releasing the pressure, the mixture formed by compression molding in step 2) together with the mold is heated to 140° C. and kept warm for 60 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0088] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0089] Example 3

[0090] This embodiment provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 90wt% of ultra-high molecular weight polyethylene with a molecular weight of 3 million and 10% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0091] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0092] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 3 million, frozen and crushed powdered nitrile rubber with a particle size of 0.5 mm, and peroxide DCP are uniformly mixed by high-speed mixing to obtain a mixture;

[0093] The amount of DCP is 0.1wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0094] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 130° C. and a pressure of 10 T, the compression molding time being 8 min.

[0095] 3) After releasing the pressure, the mixture formed by compression molding in step 2) together with the mold is heated to 200° C. and kept warm for 8 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0096] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0097] Example 4

[0098] This embodiment provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 95wt% of ultra-high molecular weight polyethylene with a molecular weight of 3.5 million and 5% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0099] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0100] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 3.5 million, frozen and crushed powdered nitrile rubber with a particle size of 0.4 mm, and peroxide DCP are uniformly mixed by high-speed mixing to obtain a mixture;

[0101] The amount of DCP is 1.5wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0102] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizing press at 135° C. and a pressure of 50T, the compression molding time being 20 minutes.

[0103] 3) After releasing the pressure, the mixture formed by compression molding in step 2) together with the mold is heated to 180° C. and kept warm for 15 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0104] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0105] Example 5

[0106] The present embodiment provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, comprising ultra-high molecular weight polyethylene with a molecular weight of 3.5 million, nitrile rubber powder zinc oxide, stearic acid, sulfur and accelerator TBBS; based on the mass of ultra-high molecular weight polyethylene and nitrile rubber powder as 100%, it contains 95wt% of ultra-high molecular weight polyethylene with a molecular weight of 3.5 million and 5% of nitrile rubber powder; zinc oxide accounts for 3wt% of the amount of nitrile rubber powder, stearic acid accounts for 1wt% of the amount of nitrile rubber powder, sulfur accounts for 1.5wt% of the amount of nitrile rubber powder, and accelerator TBBS accounts for 1wt% of the amount of nitrile rubber powder; wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by CC chemical bonds. The composite elastic material has an island structure.

[0107] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0108] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 3.5 million, frozen and crushed powdered nitrile rubber with a particle size of 0.4 mm, peroxide DCP, zinc oxide, stearic acid, sulfur and accelerator TBBS are uniformly mixed by high-speed mixing to obtain a mixture;

[0109] The amount of DCP is 2.8wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0110] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizing press at 135° C. and a pressure of 50T, the compression molding time being 15 minutes.

[0111] 3) After releasing the pressure, the mixture formed by compression molding in step 2) together with the mold is heated to 180° C. and kept warm for 15 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0112] 4) After the mixture of step 3) and the mold are cooled to room temperature, the product is taken out.

[0113] Example 6

[0114] This embodiment provides an ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, which contains 80wt% of ultra-high molecular weight polyethylene with a molecular weight of 2 million and 20% of nitrile rubber powder, taking the mass of the composite elastic material as 100% (the DCP content is negligible); wherein the nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the two phases are linked by a CC chemical bond. The composite elastic material has an island structure.

[0115] The preparation method of the above-mentioned ultra-high molecular weight polyethylene-nitrile rubber composite elastic material is as follows:

[0116] 1) ultra-high molecular weight polyethylene with a number average molecular weight of 2 million, frozen and crushed powdered nitrile rubber with a particle size of 0.6 mm, and peroxide DCP are uniformly mixed by high-speed mixing to obtain a mixture;

[0117] The amount of DCP is 1wt% of the total mass of powdered nitrile rubber and ultra-high molecular weight polyethylene;

[0118] 2) placing the mixture obtained in step 1) in a mold, and performing compression molding using a flat vulcanizer at 120° C. and a pressure of 40T, the compression molding time being 50 minutes.

[0119] 3) The mixture formed by compression molding in step 2) together with the mold is directly heated to 160° C. on a flat vulcanizer without releasing the pressure, and kept warm for 10 minutes. This process can realize the CC chemical bond connection between the powdered nitrile phase and the ultra-high molecular weight polyethylene phase;

[0120] 4) After the mixture in step 3) is cooled to room temperature together with the mold, the product is taken out. This method does not require pressure release, so that the operation time can be effectively shortened.

[0121] The products obtained in the above embodiments and comparative examples were subjected to the following performance tests, and the specific test results are shown below. The test method is as follows:

[0122] Tensile strength and yield elongation: GB / T 1040-2018;

[0123] Flexural modulus: GB / T 9341-2008;

[0124] Compression set at constant strain at room temperature: GB / T 1683-2018;

[0125] Resilience: GB / T 1681-1991.

[0126] Table 1

[0127]

[0128] From the data in the above table, it can be seen that the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material provided by the present invention has high strength, elongation and bending modulus, and also has low compression permanent deformation. From the comparison between Example 1 and Example 6, it can be seen that after compression molding, directly heating without releasing the pressure can shorten the preparation time and improve the efficiency, but the overall effect is correspondingly worse.

[0129] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. An ultra-high molecular weight polyethylene-nitrile rubber composite elastic material, characterized in that: The invention comprises 70wt%-95wt% of ultra-high molecular weight polyethylene and 5wt%-30wt% of nitrile rubber powder; and has an island structure; The nitrile rubber powder is a dispersed phase, the ultra-high molecular weight polyethylene is a continuous phase, and the dispersed phase and the continuous phase are connected by a CC chemical bond; the particle size of the nitrile rubber powder is ≤0.7 mm.

2. The ultra-high molecular weight polyethylene-nitrile rubber composite elastic material according to claim 1, characterized in that: The ultra-high molecular weight polyethylene has a number average molecular weight of 1.5-10 million and is in powder form.

3. The ultra-high molecular weight polyethylene-nitrile rubber composite elastic material according to claim 1, characterized in that: The ultra-high molecular weight polyethylene-nitrile rubber composite elastic material also includes sulfur, an accelerator, zinc oxide and stearic acid.

4. A method for preparing the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material according to any one of claims 1 to 3, characterized in that: The steps include: The ultra-high molecular weight polyethylene, nitrile rubber powder and a cross-linking agent are uniformly mixed, and then pressed into shape, and then cross-linked and cooled to obtain the ultra-high molecular weight polyethylene-nitrile rubber composite elastic material; Wherein, the temperature of the compression molding step is greater than the softening temperature of the ultra-high molecular weight polyethylene and less than the decomposition temperature of the cross-linking agent; The cross-linking temperature is greater than the decomposition temperature of the cross-linking agent, and neither the nitrile rubber powder nor the ultra-high molecular weight polyethylene is degraded.

5. The preparation method according to claim 4, characterized in that: The cross-linking step is carried out under normal pressure.

6. The preparation method according to claim 4, characterized in that: The amount of the cross-linking agent used is 0.1wt%-4wt% of the total amount of the ultra-high molecular weight polyethylene and the nitrile rubber powder.

7. The preparation method according to claim 4, characterized in that: The crosslinking agent is a peroxide crosslinking agent.

8. The preparation method according to claim 4, characterized in that: The temperature of the compression molding is 110-140°C.

9. The preparation method according to claim 4, characterized in that: The cross-linking temperature is 140-200°C.

10. The preparation method according to claim 4, characterized in that: The method further comprises the step of mixing sulfur, an accelerator, zinc oxide and stearic acid together with the ultra-high molecular weight polyethylene, the nitrile rubber powder and the cross-linking agent.

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