Composite anti-aging agent, preparation method thereof and rubber product

Abstract

The invention provides a composite anti-aging agent, a preparation method thereof and a rubber product. The composite anti-aging agent provided by the invention comprises the following components in parts by weight: 100.0 parts of carbon black, 2.0-5.0 parts of an anti-aging agent, 2.0-5.0 parts of polyethylene glycol, 0.1-0.2 part of ethylene-butadiene rubber and 0.1-2.0 parts of a silane coupling agent. A large number of studies find that polyethylene glycol is used as a dispersing agent, and the anti-aging agent and a trace amount of ethylene-butadiene rubber are jointly dispersed and loaded on the carrier carbon black, so that the anti-aging agent, the carbon black and the ethylene-butadiene rubber form a stable combination system, the effect of the anti-aging agent can be exerted to a greater extent, and the anti-aging performance of a product is improved.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, in particular to a composite antioxidant and a preparation method thereof, and a rubber product. Background Art

[0002] The equipment box control unit in the power grid system operates in various high-temperature environments. Although the static seal is only a small unit in the equipment box system, once its performance is reduced or damaged, it will cause the entire system to fail. When in a high-temperature environment for a long time, the size and mechanical strength of the seal will be reduced, and it is easy to deform and shift, which will lead to the deterioration of the sealing performance of the system, making the power system affected by external dust, water vapor, etc. After these impurities enter the equipment box, they may adhere to the electrical components, affecting their heat dissipation, causing local overheating, and even causing short circuits, discharges and other faults.

[0003] Antioxidants are usually added during the rubber preparation process to improve the high temperature aging resistance of rubber products. However, the dispersion of antioxidants in the rubber matrix will have a significant impact on the high temperature aging resistance and mechanical strength of rubber products, thereby affecting the service life of rubber products.

[0004] Therefore, it is necessary to provide a composite antioxidant having excellent dispersibility in a rubber matrix. Summary of the invention

[0005] The purpose of the present invention is to provide a composite antioxidant with high dispersibility for use in rubber products in order to overcome the above problems and extend the service life of rubber products in a high temperature environment.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a composite antioxidant, comprising the following components in parts by weight:

[0008] 100.0 parts of carbon black, 2.0-5.0 parts of antioxidant, 2.0-5.0 parts of polyethylene glycol, 0.1-0.2 parts of ethylene-butadiene rubber, and 0.1-2.0 parts of silane coupling agent.

[0009] Preferably, the weight average molecular weight of the polyethylene glycol is 200-600.

[0010] Preferably, the Mooney viscosity of the ethylene-butadiene rubber at ML (1+4) and 100° C. is 47 to 53 MU.

[0011] Preferably, the reactive monomers of the ethylene-butene rubber include ethylene, butene and non-conjugated polyene, and the mass of ethylene accounts for 48-53% of the total mass of the reactive monomers.

[0012] Preferably, the antioxidant includes at least one of 2-mercaptobenzimidazole zinc salt, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, and N,N'-di(β-naphthyl)-p-phenylenediamine.

[0013] Preferably, the silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinyltri(β-methoxyethoxy)silane.

[0014] Preferably, the particle size of the carbon black is ≤50 μm.

[0015] The second aspect of the present invention provides a method for preparing the composite antioxidant according to the first aspect of the present invention, comprising the following steps:

[0016] S1 Preparation of dispersion

[0017] According to the weight parts, the antioxidant and the silane coupling agent are dispersed in water to form an antioxidant dispersion; the ethylene-butadiene rubber and the silane coupling agent are dispersed in water to form an ethylene-butadiene rubber dispersion; the polyethylene glycol is dissolved in water to form a polyethylene glycol dispersion;

[0018] S2 Granulation

[0019] The antioxidant dispersion and ethylene-butadiene rubber dispersion prepared in step S1 are added to the polyethylene glycol dispersion, and mixed evenly with carbon black to form a homogeneous slurry. The homogeneous slurry is injected into a granulation device for granulation, and then dried and sieved to obtain the composite antioxidant.

[0020] Preferably, the solid content of the homogenized slurry in step S2 is 50-60 wt.%.

[0021] The third aspect of the present invention provides a rubber product comprising the following components in parts by weight:

[0022] 100.0 parts of base rubber, 40.0-60.0 parts of the composite antioxidant described in the first aspect of the present invention, 4.0-6.0 parts of a vulcanizing agent, 10.0-20.0 parts of an inorganic filler, and 0.0-20.0 parts of a processing aid.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The invention loads antioxidant, polyethylene glycol and ethylene-butadiene rubber onto a carbon black carrier, thereby significantly improving the dispersibility and high temperature aging resistance of the antioxidant in the product. DETAILED DESCRIPTION

[0025] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

[0026] The first aspect of the present invention provides a composite antioxidant, comprising the following components in parts by weight:

[0027] 100.0 parts of carbon black, 2.0-5.0 parts of antioxidant, 2.0-5.0 parts of polyethylene glycol, 0.1-0.2 parts of ethylene-butadiene rubber, and 0.1-2.0 parts of silane coupling agent.

[0028] Loading the antioxidant onto a carrier to prepare a loaded composite antioxidant can improve the dispersibility of the antioxidant in the rubber matrix and give full play to the high temperature aging resistance of the antioxidant. Carbon black is a carrier with excellent adsorption performance due to its excellent stability and specific surface area; however, carbon black will inhibit the anti-aging effect of the antioxidant. The present invention has found through a large number of studies that by using polyethylene glycol as a dispersant, the antioxidant and a trace amount of ethylene-butadiene rubber are co-dispersed and loaded onto the carrier carbon black, so that the antioxidant, carbon black and ethylene-butadiene rubber form a stable binding system, which can exert the effect of the antioxidant to a greater extent and improve the anti-aging performance of its products.

[0029] In the composite antioxidant of the present invention, carbon black is used as a carrier to absorb and disperse the antioxidant, polyethylene glycol, and ethylene-butadiene rubber, wherein: 1) polyethylene glycol can improve the dispersibility of the antioxidant in the carbon black carrier, and at the same time, polyethylene glycol is adsorbed on the carrier surface, and the stability of carbon black at high temperature can be further improved; the dispersion stability of the composite antioxidant in the matrix of its product can also be improved, and the viscosity of the product during processing can also be reduced, thereby improving the processing performance; 2) ethylene-butadiene rubber can have an adsorption effect on the antioxidant and carbon black at the same time, and plays the role of a bridge connecting the carbon black carrier and the antioxidant, thereby further stabilizing the anti-aging performance of the antioxidant. Therefore, under the joint action of polyethylene glycol and ethylene-butadiene rubber, the influence of the carbon black carrier on the performance of the antioxidant can be significantly reduced, and the use of carbon black as an antioxidant carrier can significantly improve its dispersion stability in the antioxidant product, and significantly improve the high temperature aging resistance of the antioxidant in its product.

[0030] Preferably, the weight average molecular weight of the polyethylene glycol (PEG) is 200 to 600. The molecular weight of the polyethylene glycol is within the above-mentioned suitable range, has a suitable viscosity, can be evenly dispersed on the carrier surface, and can interact more firmly with the carbon black surface to form a stable dispersion system, thereby increasing the loading amount of the antioxidant.

[0031] In the present invention, the reaction monomers of the ethylene-butadiene rubber include ethylene, butene, and non-conjugated polyenes, and the non-conjugated polyenes include but are not limited to at least one of 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene (VNB). The Mooney viscosity and segment composition of the ethylene-butadiene rubber will affect the performance of the ethylene-butadiene rubber, but since the amount of the ethylene-butadiene rubber added in the composite antioxidant of the present invention is very small, the performance of the ethylene-butadiene rubber has little effect on the high temperature aging resistance of the composite antioxidant, and the ethylene-butadiene rubber commonly used in the art can be used to prepare the composite antioxidant in the present invention.

[0032] Preferably, the Mooney viscosity of the ethylene-butadiene rubber at ML (1+4) and 100° C. is 47 to 53 MU; in the ethylene-butadiene rubber, the mass of ethylene accounts for 48 to 53% of the total mass of the reaction monomers. When the viscosity of the ethylene-butadiene rubber and the amount of the ethylene monomer are within the above-mentioned appropriate ranges, the processing performance and high temperature aging resistance of the antioxidant product can be further improved.

[0033] In the present invention, the ethylene-butadiene rubber (EBT) can be prepared by conventional synthesis methods in the art, or commercially available products can be used. Commercially available products include: EBT developed by Mitsui Chemicals, which is a terpolymer of ethylene, butene and 5-ethylidene-2-norbornene (ENB) synthesized using a metallocene catalyst, and two grades of products have been commercialized (K-9330M).

[0034] In the present invention, the Mooney viscosity of ethylene-butadiene rubber refers to the standard "ASTM D1646-2019" and is tested using a Mooney viscometer under ML (1+4) and 100°C conditions.

[0035] Preferably, the antioxidant includes at least one of 2-mercaptobenzimidazole zinc salt (antioxidant ZMTI), 2,2,4-trimethyl-1,2-dihydroquinoline polymer (antioxidant DR), N-isopropyl-N'-phenyl-p-phenylenediamine (antioxidant 4010NA), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (antioxidant 4020), 2,6-di-tert-butyl-4-methylphenol (antioxidant 264), and N,N'-di(β-naphthyl)-p-phenylenediamine (antioxidant DNP).

[0036] In the present invention, a silane coupling agent can be selectively added as needed, and the silane coupling agent includes but is not limited to at least one of γ-aminopropyl triethoxysilane (KH550), γ-(2,3-epoxypropoxy)propyl trimethoxysilane (KH560), γ-methacryloxypropyl trimethoxysilane (KH570), N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (KH792), N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxysilane (KH602), vinyl triethoxysilane (A151), vinyl trimethoxysilane (A171), and vinyl tri(β-methoxyethoxy) silane (A172). The addition of the silane coupling agent can improve the dispersibility of ethylene-butadiene rubber and polyethylene glycol.

[0037] Preferably, the particle size of the carbon black is ≤50 μm. The particle size of the carbon black is within the above-mentioned suitable range, and has both excellent adsorption performance and dispersion stability.

[0038] Preferably, the composite antioxidant comprises the following components in parts by weight:

[0039] 100.0 parts of carbon black, 3.0-5.0 parts of antioxidant, 3.0-5.0 parts of polyethylene glycol, 0.1-0.15 parts of ethylene-butadiene rubber, 1.0-2.0 parts of silane coupling agent.

[0040] Preferably, the particle size of the composite antioxidant is 200-400 μm.

[0041] The second aspect of the present invention provides a method for preparing the composite antioxidant according to the first aspect of the present invention, comprising the following steps:

[0042] S1 Preparation of dispersion

[0043] According to the weight parts, the antioxidant and the silane coupling agent are dispersed in water to form an antioxidant dispersion; the ethylene-butadiene rubber and the silane coupling agent are dispersed in water to form an ethylene-butadiene rubber dispersion; the polyethylene glycol is dissolved in water to form a polyethylene glycol dispersion;

[0044] S2 Granulation

[0045] The antioxidant dispersion and ethylene-butadiene rubber dispersion prepared in step S1 are added to the polyethylene glycol dispersion, and mixed evenly with carbon black to form a homogeneous slurry. The homogeneous slurry is injected into a granulation device for granulation, and then dried and sieved to obtain the composite antioxidant.

[0046] Preferably, the homogenized slurry in step S2 has a solid content of 50-60 wt.%. When the solid content of the slurry is within this range, the viscosity is moderate and the processing is convenient.

[0047] Preferably, the drying temperature is 150-170°C.

[0048] Firstly, the antioxidant dispersion, ethylene-butadiene rubber dispersion and polyethylene glycol dispersion are mixed to fully ensure that the antioxidant is adsorbed and attached to the surface of ethylene-butadiene rubber, and then mixed with carbon black for granulation. During the granulation process, ethylene-butadiene rubber and polyethylene glycol will be firmly attached to the surface of carbon black, so that carbon black, ethylene-butadiene rubber and antioxidant will form a stable binding system.

[0049] The third aspect of the present invention provides a rubber product, which includes the following components in parts by weight: 100.0 parts of base rubber, 40.0 to 60.0 parts of the composite antioxidant described in the first aspect of the present invention, 4.0 to 6.0 parts of a vulcanizing agent, 10.0 to 20.0 parts of an inorganic filler, and 5.0 to 20.0 parts of a processing aid.

[0050] The common rubber matrix and rubber vulcanizing agent in the art can be used in the present invention.

[0051] The vulcanizing agent includes but is not limited to at least one of triallyl isocyanurate (TAIC) and dicumyl peroxide (DCP).

[0052] The processing aids include, but are not limited to, lubricants and dispersants. Lubricants and dispersants commonly used in the art can be used in the present invention.

[0053] The inorganic filler is used to enhance the mechanical strength of the rubber. Common inorganic fillers in the art can be used in the present invention. The inorganic filler includes but is not limited to at least one of calcium carbonate, talc, and metal oxides.

[0054] The lubricant includes but is not limited to at least one of paraffin oil and stearic acid.

[0055] The following are specific embodiments of the present invention. In the embodiments and comparative examples of the present invention, the relevant raw materials used are listed as follows:

[0056] Ethylene-butadiene rubber: prepared by the following method:

[0057] Ethylene, butene and 5-ethylidene-2-norbornene (ENB) are reaction monomers, Ziegler-Natta catalyst is catalyst, benzoyl peroxide is initiator, the raw materials of the above reaction are dissolved in toluene solvent for polymerization reaction, and the following different ethylene-butadiene rubbers (EBT) are prepared by adjusting the polymerization reaction temperature, pressure and the amount ratio of the reaction monomers, as shown in Table 1:

[0058] Table 1

[0059]

[0060] Carbon black-1: ground to a particle size of 10-20 μm, commercially available;

[0061] Carbon black-2: ground to a particle size of 30-50 μm, commercially available;

[0062] Carbon black-3: ground to a particle size of 60-80 μm, commercially available;

[0063] White carbon black: average particle size is 200nm, commercially available;

[0064] PEG-200: Commercially available;

[0065] PEG-600: Commercially available;

[0066] PEG-2000: Commercially available;

[0067] Silane coupling agent: KH550, commercially available;

[0068] Antiaging agent ZMTI: commercially available;

[0069] Antioxidant DNP: commercially available.

[0070] Unless otherwise specified, the raw materials used in the embodiments of the present invention are all the same commercially available raw materials, such as the above-mentioned carbon black, which is the same commercially available product and ground into different particle sizes.

[0071] Examples 1 to 15, Comparative Examples 1 to 7

[0072] A series of composite antioxidants are provided, and the preparation method comprises the following steps:

[0073] S1 Preparation of dispersion

[0074] According to the formula (weight parts) described in Tables 2 to 3, the antioxidant and the silane coupling agent are dispersed in water to form an antioxidant dispersion; the ethylene-butadiene rubber and the silane coupling agent are dispersed in water to form an ethylene-butadiene rubber dispersion; the polyethylene glycol is dissolved in water to form a polyethylene glycol dispersion;

[0075] S2 Granulation

[0076] The antioxidant dispersion and ethylene-butadiene rubber dispersion prepared in step S1 are added to the polyethylene glycol dispersion and mixed with carbon black to form a homogeneous slurry (solid content of 50 wt.%). The homogeneous slurry is heated at 70 m 3 The composite antioxidant is obtained by inputting the composite antioxidant into the granulation system at a flow rate of / h and injecting it into the granulation equipment for granulation, and then drying it in a blast drying oven at 170°C to constant weight, and the composite antioxidant particles with a particle size in the range of 200 to 400 μm are screened out for use.

[0077] It should be noted that in the embodiment of the present invention, in step S1, the concentration of each raw material in each dispersion is not limited and can be conventionally adjusted according to the specific dosage, as long as the dispersion and mixing in step S2 can be uniform and a homogeneous slurry can be prepared for granulation.

[0078] Table 2

[0079]

[0080] Table 3

[0081]

[0082] Application Examples

[0083] The composite antioxidant obtained in the above-mentioned embodiments and comparative examples is added to a rubber matrix to prepare a rubber product. After all the raw materials are uniformly mixed according to the components in parts by weight shown in Table 4, the rubber product is vulcanized at 160°C and 15 MPa for 30 minutes to obtain the corresponding rubber product. Among them, the rubber products to which the composite antioxidant prepared in Examples 1 to 15 are added correspond to Application Examples 1 to Application Examples 15, respectively, and the rubber products to which the composite antioxidant prepared in Comparative Examples 1 to 7 are added correspond to Comparative Application Examples 1 to Comparative Application Examples 7, respectively. The "Rubber Product (Comparative)" used for comparison in Table 4 is recorded as Comparative Application Example 8.

[0084] Table 4 Rubber products

[0085] Raw materials / weight Rubber products Rubber products (comparison) Ethylene-butadiene rubber K-9330M 100 100 Composite antioxidant 50 / Carbon Black-1 / 50 Antioxidant ZMTI / 1 PEG-200 / 1 Curing agent DCP 4 4 Curing agent TAIC 1 1 Stearic acid 2 2 Paraffin oil 10 10 Calcium carbonate 10 10 Zinc Oxide 5 5

[0086] Performance Testing

[0087] 1. Initial mechanical strength test: According to the test method in the standard "GB / T 528-2009", after sample preparation, tensile test and Shore A hardness test were carried out at a speed of 50 mm / min in an environment of 25±2℃. The test results are detailed in Table 5;

[0088] 2. High temperature aging resistance test: The rubber product is placed in an environment of 100°C, left to stand for 72 hours, taken out, and after cooling, the mechanical properties of the product after high temperature aging are further tested according to the above method, and the change rate (%) of the relevant mechanical properties is calculated. Taking tensile strength as an example, the change rate of tensile strength = |mechanical strength after aging-initial mechanical strength before aging| / initial mechanical strength before aging × 100%. The calculation formulas for the change rates of other properties are the same. The specific test results are shown in Table 5;

[0089] Table 5 Performance test results

[0090]

[0091]

[0092] From the above results we can see that:

[0093] The composite antioxidant prepared by the present invention has good dispersibility in the rubber matrix, and carbon black as a carrier further improves its dispersion stability in the matrix. The prepared rubber product has excellent initial mechanical strength and can maximize the high temperature aging resistance of the antioxidant.

[0094] No ethylene-butadiene rubber was added to the composite antioxidant in Comparative Example 1, no polyethylene glycol was added in Comparative Example 5, and no polyethylene glycol or ethylene-butadiene rubber was added in Comparative Example 6. The high temperature aging resistance of the rubber products prepared using these composite antioxidants was significantly reduced.

[0095] In Comparative Example 7, the composite antioxidant uses white carbon black as a carrier, and the initial mechanical strength of the rubber product prepared is significantly deteriorated.

[0096] In Comparative Example 2, more ethylene-butadiene rubber is added, and more ethylene-butadiene rubber will cover and devour the antioxidant, affecting the performance of the antioxidant. The high-temperature aging resistance of the prepared rubber product will also be significantly deteriorated.

[0097] In Comparative Examples 3 and 4, rubber components of other compositions were added, and the aging resistance of the obtained rubber products also deteriorated significantly.

[0098] The performance comparison results of the above embodiments and comparative examples show that by using polyethylene glycol as a dispersant, the antioxidant and a trace amount of ethylene-butadiene rubber are dispersed and loaded onto the carrier carbon black, so that the antioxidant, carbon black and ethylene-butadiene rubber form a stable binding system, which can exert the efficacy of the antioxidant to a greater extent and improve the anti-aging performance of the product.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A composite antioxidant, characterized in that: The invention comprises the following components in parts by weight: 100.0 parts of carbon black, 2.0-5.0 parts of antioxidant, 2.0-5.0 parts of polyethylene glycol, 0.1-0.2 parts of ethylene-butadiene rubber and 0.1-2.0 parts of silane coupling agent.

2. The composite antioxidant according to claim 1, characterized in that: The weight average molecular weight of the polyethylene glycol is 200-600.

3. The composite antioxidant according to claim 1, characterized in that: The Mooney viscosity of the ethylene-butadiene rubber at ML (1+4) and 100° C. is 47 to 53 MU.

4. The composite antioxidant according to claim 1, characterized in that: The reaction monomers of the ethylene-butene rubber include ethylene, butene and non-conjugated polyene, and the mass of ethylene accounts for 48-53% of the total mass of the reaction monomers.

5. The composite antioxidant according to claim 1, characterized in that: The antioxidant includes at least one of 2-mercaptobenzimidazole zinc salt, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, and N,N'-di(β-naphthyl)-p-phenylenediamine.

6. The composite antioxidant according to claim 1, characterized in that: The silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinyltri(β-methoxyethoxy)silane.

7. The composite antioxidant according to claim 1, characterized in that: The particle size of the carbon black is ≤50 μm.

8. The method for preparing the composite antioxidant according to any one of claims 1 to 7, characterized in that: The steps include: S1 Preparation of dispersion According to the weight parts, the antioxidant and the silane coupling agent are dispersed in water to form an antioxidant dispersion; the ethylene-butadiene rubber and the silane coupling agent are dispersed in water to form an ethylene-butadiene rubber dispersion; the polyethylene glycol is dissolved in water to form a polyethylene glycol dispersion; S2 Granulation The antioxidant dispersion and ethylene-butadiene rubber dispersion prepared in step S1 are added to the polyethylene glycol dispersion, and mixed evenly with carbon black to form a homogeneous slurry. The homogeneous slurry is injected into a granulation device for granulation, and then dried and sieved to obtain the composite antioxidant.

9. The method for preparing the composite antioxidant according to claim 8, characterized in that: The solid content of the homogenized slurry in step S2 is 50-60 wt.%.

10. A rubber product, characterized in that: The composition comprises the following components in parts by weight: 100.0 parts of base rubber, 40.0-60.0 parts of the composite antioxidant according to any one of claims 1 to 7, 4.0-6.0 parts of a vulcanizing agent, 10.0-20.0 parts of an inorganic filler, and 0.0-20.0 parts of a processing aid.

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