Anti-ultraviolet rubber composite material and preparation method thereof

Abstract

The invention belongs to the field of rubber materials, and particularly relates to an anti-ultraviolet rubber composite material and a preparation method thereof. The rubber composite material provided by the invention is prepared from the following raw materials in parts by weight: 100 parts of natural rubber, 10 to 20 parts of styrene-maleic anhydride-acrylonitrile terpolymer, 5 to 10 parts of composite anti-ultraviolet agent, 4 to 8 parts of activating agent, 20 to 40 parts of reinforcing agent, 2 to 4 parts of anti-aging agent, 1 to 2.8 parts of accelerant and 1 to 2.8 parts of vulcanizing agent, the composite anti-ultraviolet agent comprises nano spherical cerium oxide, and an organic micromolecule anti-ultraviolet agent and a modifier which are loaded on the surface of the nano spherical cerium oxide, and the mass ratio of the nano spherical cerium oxide to the organic micromolecule anti-ultraviolet agent to the modifier is 100: (1-5): (2-6). The rubber composite material provided by the invention has excellent ultraviolet resistance and mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of rubber materials, and particularly relates to an ultraviolet-resistant rubber composite material and its preparation method. Background Technology

[0002] Natural rubber, as a high-performance polymer material, possesses high elasticity, good wear resistance, and high tensile strength, making it widely used in tires, seals, medical devices, daily necessities, and many other fields. However, the molecular structure of natural rubber contains a large number of unsaturated double bonds, making it highly susceptible to oxidative degradation under ultraviolet (UV) radiation. This leads to aging phenomena such as decreased mechanical properties, cracking, and discoloration, severely impacting product lifespan and safety. Traditional methods for improving the UV aging resistance of natural rubber mainly involve adding organic UV absorbers and antioxidants. However, these organic additives suffer from problems such as migration, volatilization, and extraction, resulting in a gradual decrease in their UV resistance over long-term use, which limits the application of rubber materials to some extent. Furthermore, simply adding UV absorbers often fails to simultaneously maintain the material's mechanical properties. Therefore, how to improve the UV aging resistance of natural rubber while maintaining or even enhancing its mechanical strength has always been a research hotspot and challenge in this field.

[0003] With the continuous expansion of applications for rubber products, such as outdoor products, automobile tires, and building sealing materials, higher requirements are being placed on the weather resistance and service life of rubber products. Therefore, developing a natural rubber composite material with long-lasting and efficient UV resistance and excellent comprehensive mechanical properties has significant practical significance and application value. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an anti-ultraviolet rubber composite material and a method for preparing the same. The rubber composite material provided by the present invention has excellent anti-ultraviolet properties and mechanical properties.

[0005] This invention provides a UV-resistant rubber composite material, comprising, by weight, the following raw materials:

[0006] 100 parts natural rubber;

[0007] 10-20 parts of styrene-maleic anhydride-acrylonitrile terpolymer;

[0008] 5-10 parts of compound UV protectant;

[0009] Activator 4-8 parts;

[0010] 20-40 parts of reinforcing agent;

[0011] Anti-aging agent 2-4 parts;

[0012] Accelerator 1-2.8 parts;

[0013] 1-2.8 parts of vulcanizing agent;

[0014] The composite UV stabilizer includes nano-spherical cerium oxide and organic small molecule UV stabilizers and modifiers loaded on the surface of the nano-spherical cerium oxide, wherein the mass ratio of the nano-spherical cerium oxide, organic small molecule UV stabilizers and modifiers is 100:(1~5):(2~6).

[0015] Preferably, the nano-spherical cerium oxide has a particle size of 200-400 nm and a specific surface area of ​​100-200 m². 2 / g.

[0016] Preferably, the organic small molecule UV stabilizer is one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and bis(2,2,6,6-tetramethyl-4-piperidine) sebacate.

[0017] Preferably, the modifier is one or more selected from bis-[γ-(triethoxysilyl)propyl]amine, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0018] Preferably, the weight-average molecular weight of the styrene-maleic anhydride-acrylonitrile terpolymer is 4000~6000; the molar ratio of the repeating unit corresponding to styrene, the repeating unit corresponding to maleic anhydride and the repeating unit corresponding to acrylonitrile in the styrene-maleic anhydride-acrylonitrile terpolymer is (4~6):(2~3):(2~3).

[0019] Preferably, the activator is zinc oxide and stearic acid, and the mass ratio of zinc oxide to stearic acid is (3~5):1;

[0020] The reinforcing agent is one or more of carbon black, silica, calcium carbonate, clay, talc, barium sulfate, and montmorillonite.

[0021] The antioxidant is one or more of the following: 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, N-phenyl-α-naphthylamine, N-phenyl-β-naphthylamine, 2,6-di-tert-butyl-p-cresol, N-isopropyl-N'-phenyl-p-phenylenediamine, 2-mercaptobenzimidazole, N-isopropyl-N'-phenyl-p-phenylenediamine, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and N,N'-di(β-naphthyl)-p-phenylenediamine;

[0022] The accelerator is one or more selected from 2,2'-dithiodibenzothiazole, 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole, diphenylguanidine, di-o-tolueneguanidine, N,N-tetramethyldisulfide disulfide carbonylamine, tetraethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, and N,N'-dicyclohexyl-2-benzothiazole sulfenamide.

[0023] The vulcanizing agent is one or more of sublimed sulfur, precipitated sulfur, and insoluble sulfur.

[0024] This invention provides a method for preparing the UV-resistant rubber composite material described above, comprising the following steps:

[0025] Natural rubber, styrene-maleic anhydride-acrylonitrile terpolymer, composite UV stabilizer, activator, reinforcing agent, antioxidant, accelerator and vulcanizing agent are mixed and vulcanized to obtain UV-resistant rubber composite material.

[0026] Preferably, the composite UV stabilizer is prepared according to the following steps:

[0027] i) Mix the organic small molecule UV stabilizer, some modifiers and solvents to obtain a UV stabilizer mixed solution;

[0028] ii) Mix cerium oxide nanospheres with a portion of the modifier to obtain modified nanospheres;

[0029] Steps i) and ii) are not in any particular order;

[0030] iii) The UV-resistant agent mixture solution is sprayed onto the surface of the modified nanospheres, and the solvent is evaporated to obtain the composite UV-resistant agent.

[0031] Preferably, the mass ratio of the modifier in step i) to the modifier in step ii) is 1:(0.5~2).

[0032] Preferably, in step ii), the mixing temperature is 80~100℃, the vacuum degree is 0.05~0.08MPa, and the time is 1~2h.

[0033] Compared with the prior art, the present invention provides an anti-ultraviolet rubber composite material and its preparation method. By weight, the raw materials for preparing the rubber composite material provided by the present invention include: 100 parts natural rubber, 10-20 parts styrene-maleic anhydride-acrylonitrile terpolymer, 5-10 parts composite anti-ultraviolet agent, 4-8 parts activator, 20-40 parts reinforcing agent, 2-4 parts antioxidant, 1-2.8 parts accelerator, and 1-2.8 parts vulcanizing agent; the composite anti-ultraviolet agent includes nano-spherical cerium oxide and an organic small molecule anti-ultraviolet agent and modifier loaded on the surface of the nano-spherical cerium oxide, wherein the mass ratio of the nano-spherical cerium oxide, the organic small molecule anti-ultraviolet agent, and the modifier is 100:(1-5):(2-6). This invention uses nano-spherical cerium oxide as a carrier and constructs an inorganic-organic composite UV resistant agent by loading organic small-molecule UV resistant agents onto its surface. This simultaneously improves the dispersibility and compatibility of the UV resistant agent with the rubber matrix. A styrene-maleic anhydride-acrylonitrile terpolymer is used as a macromolecular UV shielding agent, working synergistically with the composite UV resistant agent to construct a composite system with the synergistic effect of macromolecules and small molecules. This optimizes the UV resistance of natural rubber from multiple dimensions and in all aspects, forming a multi-layered UV protection barrier that effectively resists the damage of ultraviolet rays to natural rubber. Furthermore, the introduction of the terpolymer significantly improves key mechanical properties of natural rubber, such as tensile strength and tear strength, greatly expanding the application scenarios of natural rubber under complex environmental conditions. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention provides a UV-resistant rubber composite material, which is made by vulcanizing and mixing raw materials. The raw materials, by weight, include:

[0036] 100 parts natural rubber;

[0037] 10-20 parts of styrene-maleic anhydride-acrylonitrile terpolymer;

[0038] 5-10 parts of compound UV protectant;

[0039] Activator 4-8 parts;

[0040] 20-40 parts of reinforcing agent;

[0041] Anti-aging agent 2-4 parts;

[0042] Accelerator 1-2.8 parts;

[0043] 1 to 2.8 parts of vulcanizing agent.

[0044] In the rubber composite material provided by the present invention, the content of cis-1,4-polyisoprene in the natural rubber is preferably 91~94wt%, specifically 91wt%, 91.5wt%, 91.8wt%, 92wt%, 92.5wt%, 93wt%, 93.5wt%, or 94wt%; the Mooney viscosity [ML(1+4)100℃] of the natural rubber is preferably 60~70, specifically 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, or 70.

[0045] In the rubber composite material provided by the present invention, the weight-average molecular weight of the styrene-maleic anhydride-acrylonitrile terpolymer is preferably 4000~6000, specifically 4000, 4200, 4500, 4700, 5000, 5200, 5500, 5700 or 6000; the molar ratio of the repeating unit corresponding to styrene, the repeating unit corresponding to maleic anhydride and the repeating unit corresponding to acrylonitrile in the styrene-maleic anhydride-acrylonitrile terpolymer is preferably (4~6):(2~3):(2~3), specifically 4:3:3, 4.5:2.7:2.8, 5:2.5:2.5, 5.5:2.3:2.2 or 6:2:2.

[0046] In the rubber composite material provided by the present invention, based on the content of natural rubber in the raw material being 100 parts by weight, the content of the styrene-maleic anhydride-acrylonitrile terpolymer in the raw material can specifically be 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, or 20 parts by weight.

[0047] In the rubber composite material provided by the present invention, the composite UV stabilizer includes nano-spherical cerium oxide and organic small molecule UV stabilizers and modifiers loaded on the surface of the nano-spherical cerium oxide.

[0048] In the rubber composite material provided by the present invention, the particle size of the nano-spherical cerium oxide is preferably 200~400 nm, specifically 200 nm, 230 nm, 250 nm, 270 nm, 300 nm, 320 nm, 350 nm, 370 nm or 400 nm; the specific surface area of ​​the nano-spherical cerium oxide is preferably 100~200 m² / g. 2 / g, specifically 100m 2 / g、110m 2 / g, 120m 2 / g, 130m 2 / g, 140m2 / g, 150m 2 / g, 160m 2 / g、170m 2 / g、180m 2 / g、190m 2 / g or 200m 2 / g.

[0049] In the rubber composite material provided by the present invention, the organic small molecule UV stabilizer is preferably one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and bis(2,2,6,6-tetramethyl-4-piperidine) sebacate. In some embodiments provided by the present invention, the organic small molecule UV stabilizer is 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole and 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and the mass ratio of 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole to 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole is preferably 1:(0.5~2), more preferably 1:1. In some embodiments provided by the present invention, the organic small molecule UV stabilizer is 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and bis(2,2,6,6-tetramethyl-4-piperidine) sebacate. The mass ratio of 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and bis(2,2,6,6-tetramethyl-4-piperidine) sebacate is preferably 2:(0.5~2):(1~5), more preferably 2:1:2.

[0050] In the rubber composite material provided by the present invention, the modifier is preferably one or more selected from bis-[γ-(triethoxysilyl)propyl]amine, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane. In some embodiments provided by the present invention, the modifier is γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, and the mass ratio of γ-aminopropyltriethoxysilane to γ-glycidoxypropyltrimethoxysilane is preferably 1:(1~5), more preferably 1:3.5. In some embodiments provided by the present invention, the modifier is bis-[γ-(triethoxysilyl)propyl]amine, γ-methacryloxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane, wherein the mass ratio of bis-[γ-(triethoxysilyl)propyl]amine, γ-methacryloxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane is preferably 1:(0.5~2):(0.5~2), more preferably 1:1:1.

[0051] In the rubber composite material provided by the present invention, the preferred mass ratio of the nano-spherical cerium oxide, the organic small molecule UV stabilizer, and the modifier is 100:(1~5):(2~6); wherein, the specific mass ratio of the nano-spherical cerium oxide and the organic small molecule UV stabilizer can be 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, or 100:5, and the specific mass ratio of the nano-spherical cerium oxide and the modifier can be 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, 100:5, 100:5.5, or 100:6.

[0052] In the rubber composite material provided by the present invention, based on the content of natural rubber in the raw material being 100 parts by weight, the content of the composite UV stabilizer in the raw material can specifically be 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, or 10 parts by weight.

[0053] In the rubber composite material provided by the present invention, the activator is preferably zinc oxide and stearic acid; the mass ratio of zinc oxide and stearic acid is preferably (3~5):1, specifically 3:1, 3.2:1, 3.5:1, 3.7:1, 4:1, 4.2:1, 4.5:1, 4.7:1 or 5:1.

[0054] In the rubber composite material provided by the present invention, based on 100 parts by weight of natural rubber in the raw material, the content of the activator in the raw material can specifically be 4 parts by weight, 4.2 parts by weight, 4.5 parts by weight, 4.7 parts by weight, 5 parts by weight, 5.2 parts by weight, 5.5 parts by weight, 5.7 parts by weight, 6 parts by weight, 6.2 parts by weight, 6.5 parts by weight, 6.7 parts by weight, 7 parts by weight, 7.2 parts by weight, 7.5 parts by weight, 7.7 parts by weight, or 8 parts by weight.

[0055] In the rubber composite material provided by this invention, the reinforcing agent is preferably one or more of carbon black, silica, calcium carbonate, kaolin, talc, barium sulfate, and montmorillonite with a particle size of 50-90 μm; wherein, the particle size of the carbon black is preferably 80-100 nm, specifically 80 nm, 85 nm, 90 nm, 95 nm, or 100 nm; the particle size of the silica is preferably 30-90 nm, specifically 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, or 90 nm; the particle size of the calcium carbonate is preferably 20-50 μm, specifically 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm; the particle size of the kaolin is preferably 3-10 μm, with… The particle size can be 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm or 10μm; the particle size of the talc powder is preferably 32~85μm, specifically 32μm, 35μm, 40μm, 45μm, 50μm, 52μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm or 85μm; the particle size of the barium sulfate is preferably 10~45μm, specifically 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm or 45μm; the particle size of the montmorillonite is preferably 50~90μm, specifically 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm or 90μm. In some embodiments of the present invention, the reinforcing agent is clay and talc, and the mass ratio of clay to talc is preferably 17:(15~20), more preferably 17:18. In some embodiments of the present invention, the reinforcing agent is barium sulfate and montmorillonite, and the mass ratio of barium sulfate to montmorillonite is preferably 1:(0.5~2), more preferably 1:1.

[0056] In the rubber composite material provided by the present invention, based on 100 parts by weight of natural rubber in the raw material, the content of the reinforcing agent in the raw material can specifically be 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, or 40 parts by weight.

[0057] In the rubber composite material provided by the present invention, the antioxidant is preferably one or more of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, N-phenyl-α-naphthylamine, N-phenyl-β-naphthylamine, 2,6-di-tert-butyl-p-cresol, N-isopropyl-N'-phenyl-p-phenylenediamine, 2-mercaptobenzimidazole, N-isopropyl-N'-phenyl-p-phenylenediamine, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and N,N'-di(β-naphthyl)-p-phenylenediamine. In some embodiments of the present invention, the antioxidant is N-isopropyl-N'-phenyl-p-phenylenediamine and 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and the mass ratio of N-isopropyl-N'-phenyl-p-phenylenediamine to 2,2'-methylenebis(4-methyl-6-tert-butylphenol) is preferably 1.7:(1.5~2), more preferably 1.7:1.8. In some embodiments of the present invention, the antioxidant is 2,2'-methylenebis(4-methyl-6-tert-butylphenol) and N,N'-di(β-naphthyl)-p-phenylenediamine, and the mass ratio of 2,2'-methylenebis(4-methyl-6-tert-butylphenol) to N,N'-di(β-naphthyl)-p-phenylenediamine is preferably 1:(0.5~2), more preferably 1:1.

[0058] In the rubber composite material provided by the present invention, based on 100 parts by weight of natural rubber in the raw material, the content of antioxidant in the raw material can specifically be 2 parts by weight, 2.1 parts by weight, 2.2 parts by weight, 2.3 parts by weight, 2.4 parts by weight, 2.5 parts by weight, 2.6 parts by weight, 2.7 parts by weight, 2.8 parts by weight, 2.9 parts by weight, 3 parts by weight, 3.1 parts by weight, 3.2 parts by weight, 3.3 parts by weight, 3.4 parts by weight, 3.5 parts by weight, 3.6 parts by weight, 3.7 parts by weight, 3.8 parts by weight, 3.9 parts by weight, or 4 parts by weight.

[0059] In the rubber composite material provided by the present invention, the accelerator is preferably one or more selected from 2,2'-dithiodibenzothiazole, 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole, diphenylguanidine, di-o-tolueneguanidine, N,N-tetramethyldisulfide disulfide carbonylamine, tetraethylthiuram disulfide, tetrasulfide bispentamethylenethiuram, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, and N,N'-dicyclohexyl-2-benzothiazole sulfenamide. In some embodiments provided by the present invention, the accelerator is N-cyclohexyl-2-benzothiazole sulfenamide and N-tert-butyl-2-benzothiazole sulfenamide, and the mass ratio of N-cyclohexyl-2-benzothiazole sulfenamide to N-tert-butyl-2-benzothiazole sulfenamide is preferably 1:(0.5~2), more preferably 1:1. In some embodiments provided by the present invention, the accelerator is N-tert-butyl-2-benzothiazole sulfenamide and N,N'-dicyclohexyl-2-benzothiazole sulfenamide, and the mass ratio of N-tert-butyl-2-benzothiazole sulfenamide to N,N'-dicyclohexyl-2-benzothiazole sulfenamide is preferably 1:(0.5~2), more preferably 1:1.

[0060] In the rubber composite material provided by the present invention, based on 100 parts by weight of natural rubber in the raw material, the content of the accelerator in the raw material can specifically be 1 part by weight, 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight, 2 parts by weight, 2.1 parts by weight, 2.2 parts by weight, 2.3 parts by weight, 2.4 parts by weight, 2.5 parts by weight, 2.6 parts by weight, 2.7 parts by weight, or 2.8 parts by weight.

[0061] In the rubber composite material provided by the present invention, the vulcanizing agent is preferably one or more of sublimed sulfur, precipitated sulfur, and insoluble sulfur. In some embodiments provided by the present invention, the vulcanizing agent is precipitated sulfur and insoluble sulfur, and the mass ratio of precipitated sulfur to insoluble sulfur is preferably 1:(0.5~2), more preferably 1:1. In some embodiments provided by the present invention, the vulcanizing agent is precipitated sulfur and sublimed sulfur, and the mass ratio of precipitated sulfur to sublimed sulfur is preferably 1:(0.5~2), more preferably 1:1.

[0062] In the rubber composite material provided by the present invention, based on 100 parts by weight of natural rubber in the raw material, the content of the vulcanizing agent in the raw material can specifically be 1 part by weight, 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight, 2 parts by weight, 2.1 parts by weight, 2.2 parts by weight, 2.3 parts by weight, 2.4 parts by weight, 2.5 parts by weight, 2.6 parts by weight, 2.7 parts by weight, or 2.8 parts by weight.

[0063] The present invention also provides a method for preparing the UV-resistant rubber composite material described above, comprising the following steps:

[0064] Natural rubber, styrene-maleic anhydride-acrylonitrile terpolymer, composite UV stabilizer, activator, reinforcing agent, antioxidant, accelerator and vulcanizing agent are mixed and vulcanized to obtain UV-resistant rubber composite material.

[0065] In the preparation method provided by the present invention, the composite UV stabilizer is preferably prepared according to the following steps:

[0066] i) Mix the organic small molecule UV stabilizer, some modifiers and solvents to obtain a UV stabilizer mixed solution;

[0067] ii) Mix cerium oxide nanospheres with a portion of the modifier to obtain modified nanospheres;

[0068] Steps i) and ii) are not in any particular order;

[0069] iii) The UV-resistant agent mixture solution is sprayed onto the surface of the modified nanospheres, and the solvent is evaporated to obtain the composite UV-resistant agent.

[0070] In the above-mentioned preparation steps of the composite UV stabilizer provided by the present invention, the modifier in step i) and the modifier in step ii) can be the same or different; the mass ratio of the modifier in step i) to the modifier in step ii) is preferably 1:(0.5~2), specifically 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.

[0071] In the preparation steps of the composite UV stabilizer provided by the present invention, the solvent is preferably ethanol and / or isopropanol; the mass ratio of the solvent to the nano-spherical cerium oxide is preferably (50~70):100, specifically 50:100, 51:100, 52:100, 53:100, 54:100, 55:100, 56:100, 57:100, 58:100, 59:100, 60:100, 61:100, 62:100, 63:100, 64:100, 65:100, 66:100, 67:100, 68:100, 69:100 or 70:100.

[0072] In the preparation steps of the composite UV stabilizer provided by the present invention, in step i), the mixing process preferably includes: first mixing the modifier and the solvent, and then mixing with the organic small molecule UV stabilizer. The mixing temperature of the modifier and the solvent is preferably 40-50°C, the mixing speed is preferably 400-500 rpm, and the mixing time is preferably 20-40 min; the mixing with the organic small molecule UV stabilizer is preferably performed under ultrasonic assistance, with an ultrasonic frequency preferably 50-70 kHz; the mixing temperature of the organic small molecule UV stabilizer is preferably 40-50°C, the mixing speed is preferably 400-500 rpm, and the mixing time is preferably 2-4 h.

[0073] In the preparation steps of the composite UV stabilizer provided by this invention, in step ii), the mixing speed is preferably 300~400 rpm, specifically 300 rpm, 310 rpm, 320 rpm, 330 rpm, 340 rpm, 350 rpm, 360 rpm, 370 rpm, 380 rpm, 390 rpm, or 400 rpm; the mixing temperature is preferably 80~100℃, specifically 80℃, 85℃, 90℃, or 90℃. The temperature is 5℃ or 100℃; the vacuum degree of the mixing is preferably 0.05~0.08MPa, specifically 0.05MPa, 0.055MPa, 0.06MPa, 0.065MPa, 0.07MPa, 0.075MPa or 0.08MPa; the mixing time is preferably 1~2h, specifically 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h.

[0074] In the above-mentioned preparation steps of the composite UV inhibitor provided by the present invention, in step iii), the modified nanospheres are preferably stirred during the spraying process; the solvent removal by evaporation is preferably carried out under vacuum and / or stirring conditions; the solvent removal by evaporation is preferably 2-4 hours, specifically 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours.

[0075] In the preparation method provided by this invention, the styrene-maleic anhydride-acrylonitrile terpolymer is preferably plasticized before being mixed. The plasticizing temperature is preferably 150-160°C, specifically 150°C, 151°C, 152°C, 153°C, 154°C, 155°C, 156°C, 157°C, 158°C, 159°C, or 160°C; the plasticizing time is preferably 5-7 minutes, specifically 5 minutes, 5.5 minutes, 6 minutes, 6.5 minutes, or 7 minutes.

[0076] In the preparation method provided by the present invention, the specific process of mixing preferably includes:

[0077] Natural rubber, styrene-maleic anhydride-acrylonitrile terpolymer, composite UV stabilizer, activator, reinforcing agent and antioxidant are mixed in an intensive manner to obtain an intensively mixed mixture;

[0078] The internally mixed compound, vulcanizing agent, and accelerator are subjected to open milling to obtain the rubber compound to be vulcanized.

[0079] In the mixing process provided by the present invention, the specific process of the kneading preferably includes:

[0080] a) Natural rubber and styrene-maleic anhydride-acrylonitrile terpolymer are mixed in an internal mixing chamber to obtain an intermediate mixing material;

[0081] In step a), the mixing temperature is preferably 140~160℃, specifically 140℃, 142℃, 145℃, 147℃, 150℃, 152℃, 155℃, 157℃ or 160℃; the mixing time is preferably 2~4min, specifically 2min, 2.3min, 2.5min, 2.7min, 3min, 3.2min, 3.5min, 3.7min or 4min;

[0082] b) The intermediate mixing material, composite UV stabilizer, activator, reinforcing agent and antioxidant are mixed in an internal kiln to obtain a mixed mixture;

[0083] In step b), the mixing temperature is preferably 140~160℃, specifically 140℃, 142℃, 145℃, 147℃, 150℃, 152℃, 155℃, 157℃ or 160℃; the mixing time is preferably 5~8min, specifically 5min, 5.2min, 5.5min, 5.7min, 6min, 6.2min, 6.5min, 6.7min, 7min, 7.2min, 7.5min, 7.7min or 8min.

[0084] In the mixing process provided by the present invention, the specific process of the open mill preferably includes:

[0085] The internally mixed mixture is subjected to open milling on a rolling mill. After rolling, six cuts are made to turn the rubber, then an accelerator and a vulcanizing agent are added, and six more cuts are made to turn the rubber. Then, a triangular wrapping is performed to pass through the sheet, and the sheet is produced. The number of times the sheet is passed through the wrapping is preferably 3 to 5 times, specifically 3, 4, or 5 times. The thickness of the sheet is preferably 6 to 8 mm, specifically 6 mm, 6.5 mm, 7 mm, 7.5 mm, or 8 mm.

[0086] In the preparation method provided by the present invention, the vulcanization pressure is preferably 10~20 MPa, specifically 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, 16 MPa, 17 MPa, 18 MPa, 19 MPa or 20 MPa; the vulcanization temperature is preferably 150~160℃, specifically 150℃, 151℃, 152℃, 153℃, 154℃, 155℃, 156℃, 157℃, 158℃, 159℃ or 160℃; the vulcanization time is preferably 400~450s, specifically 400s, 405s, 410s, 415s, 420s, 425s, 430s, 435s, 440s, 445s or 450s.

[0087] The technical solution provided by this invention has at least the following key points:

[0088] (1) Nano-spherical cerium oxide can effectively absorb and scatter ultraviolet light, and has high-efficiency anti-ultraviolet performance; the high specific surface area of ​​nano-spherical cerium oxide provides sufficient active sites for loading organic small molecule anti-ultraviolet agents, and organic small molecules are better distributed on the surface of cerium oxide through physical adsorption and chemical bonding.

[0089] (2) The supported inorganic-organic composite UV agent system significantly improves the UV protection effect and solves the problem of easy migration and difficult dispersion of organic small molecule UV agents; at the same time, the addition of modifiers improves the dispersibility and compatibility of composite UV agents with rubber matrix, and improves the UV protection and mechanical properties of composite materials.

[0090] (3) Styrene-maleic anhydride-acrylonitrile terpolymer, as a macromolecular ultraviolet shielding agent, can effectively and efficiently absorb ultraviolet rays and convert them into visible light or heat energy, and enhance the cohesion of the material, making it more difficult for the material to undergo degradation reaction when exposed to ultraviolet rays.

[0091] (4) The terpolymer of styrene-maleic anhydride-acrylonitrile and the composite UV stabilizer work together to build a composite system with the synergistic effect of macromolecules and small molecules, which optimizes the UV resistance of natural rubber from multiple dimensions and in all aspects, forming a multi-layered UV protection barrier to effectively resist the damage of ultraviolet rays to natural rubber.

[0092] (5) The introduction of styrene-maleic anhydride-acrylonitrile terpolymer can also significantly improve the key mechanical properties of natural rubber, such as tensile strength and tear strength, and greatly broaden the application scenarios of natural rubber under complex environmental conditions.

[0093] The technical solution provided by this invention has at least the following advantages:

[0094] (1) The UV-resistant natural rubber composite material provided by the present invention has high application value, good mechanical properties, and a perfect UV protection barrier, which broadens the application scenarios of the composite material in complex environments and can be applied to multiple fields.

[0095] (2) This invention significantly improves the UV resistance of natural rubber by constructing a macromolecule-small molecule synergistic, inorganic-organic composite system; effectively improves the mechanical properties of the composite material by styrene-maleic anhydride-acrylonitrile copolymer; the process is relatively simple and the whole process is safe and environmentally friendly.

[0096] (3) The method for preparing UV-resistant natural rubber composite material provided by the present invention is simple, efficient, and has high production efficiency, and can be produced on a large scale.

[0097] For clarity, the following examples and comparative models will be used to provide a detailed description.

[0098] In the following embodiments and comparative examples provided by this invention, the evaluation methods for each performance index are as follows:

[0099] (1) Mechanical properties:

[0100] The vulcanized film was cut into dumbbell shapes with a cutter. The tensile strength and elongation at break of the composite material samples were tested using a universal electronic tensile testing machine at a tensile rate of 500 mm / min. The test standard was GB / T528-2009. The average value of five sets of data was taken as the test results.

[0101] (2) Tear resistance:

[0102] The vulcanized film was cut into angles with a cutter. The tear strength of the composite material sample was tested using a universal electronic tensile testing machine at a tensile rate of 500 mm / min. The test standard was GB / T529-2008. The average value of five sets of data was taken as the test result.

[0103] (3) Performance retention rate:

[0104] The vulcanized film was placed in a UV aging test chamber and subjected to a UV aging test for 1440 hours. The main wavelength of the UV lamp was 340nm and the total power of the UV lamp was 320W. Then, the tensile strength and tear resistance retention rate of the aged sample were tested. The test results were taken as the average of five sets of data.

[0105] Example 1

[0106] First, 1 part by weight of bis-[γ-(triethoxysilyl)propyl]amine was added to 50 parts by weight of ethanol solvent and stirred thoroughly at 40°C and 400 rpm for 20 min. Then, 1 part by weight of 2-hydroxy-4-n-octyloxybenzophenone was added, and stirring continued for 2 h. Simultaneously, an ultrasonic device was used to assist dispersion and dissolution at a frequency of 50 kHz to obtain a mixed solution of UV inhibitors. Separately, 100 parts by weight of a solution with a specific surface area of ​​100 m² was taken... 2 / g of cerium oxide nanospheres with an average particle size of 200nm and 1 part by weight of bis-[γ-(triethoxysilyl)propyl]amine were placed in a vacuum high-speed mixer. The temperature was set to 80℃, the rotation speed was 300 rpm, and the vacuum degree was set to 0.05MPa. After mixing and modification for 1h, the vacuum device was turned off. While stirring, the above-mentioned UV-resistant agent mixture was slowly sprayed into the mixture one by one. After all the mixture was sprayed, the vacuum device was turned on again and stirring was continued for 2h to ensure that the solvent was completely evaporated, thus obtaining a loaded inorganic-organic composite UV-resistant agent.

[0107] Ten parts by weight of a styrene-maleic anhydride-acrylonitrile terpolymer with a weight average molecular weight of 4000 (the molar ratio of the repeating units of styrene, maleic anhydride and acrylonitrile is 4:3:3) were plasticized in a thin pass on an open mill at a plasticizing temperature of 150°C for 5 minutes. Then, the plasticized styrene-maleic anhydride-acrylonitrile terpolymer was added to a mixer, along with 100 parts by weight of natural rubber with a cis-1,4-polyisoprene content of 91 wt% and a Mooney viscosity [ML(1+4)100℃] of 65. The mixture was then mixed at 140℃ for 2 min. Next, 5 parts by weight of the above-mentioned inorganic-organic composite antioxidant, 4 parts by weight of activator (a mixture of zinc oxide and stearic acid, with a mass ratio of zinc oxide to stearic acid of 3:1), 20 parts by weight of carbon black with a particle size of 80 nm, and 2 parts by weight of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline were added. The mixture was then mixed at 140℃ for 5 min. After internal mixing, the blend is mixed on an open mill, rolled, and then cut six times to form a sheet. One part by weight of 2,2'-dithiodibenzothiazole and one part by weight of precipitated sulfur are added, followed by another six-cutting process. The sheet is then passed through a triangular beading process three times to produce a sheet with a thickness of 6 mm. The open mill sheet is then placed on a flat vulcanizing machine for compression molding at a pressure of 10 MPa, a temperature of 150°C, and a time of 400 s, yielding the final UV-resistant rubber composite material.

[0108] The UV-resistant rubber composite material sample was tested and found to have a tensile strength of 24.6 MPa, an elongation at break of 500%, and a tear strength of 62.5 KN / m. After aging, the sample retained 94.2% of its tensile strength, 92.3% of its elongation at break, and 93.5% of its tear strength.

[0109] Example 2

[0110] First, 1.5 parts by weight of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane were added to 55 parts by weight of isopropanol solvent and stirred thoroughly at 42°C and 425 rpm for 25 min. Then, 2 parts by weight of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole were added, and stirring continued for 2.5 h. Simultaneously, an ultrasonic device was used to assist dispersion and dissolution at a frequency of 55 kHz to obtain a mixed solution of UV inhibitors. Separately, 100 parts by weight of a solution with a specific surface area of ​​125 m² was taken... 2 / g of cerium oxide nanospheres with an average particle size of 250nm and 1.5 parts by weight of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane were placed in a vacuum high-speed mixer. The temperature was set at 85℃, the rotation speed at 325 rpm, and the vacuum degree at 0.06MPa. After mixing and modification for 1.2h, the vacuum device was turned off. While stirring, the above-mentioned UV-resistant agent mixture was slowly sprayed into the mixture one by one. After all the mixture was sprayed, the vacuum device was turned on again and stirring was continued for 2.5h to ensure complete evaporation of the solvent, thus obtaining a loaded inorganic-organic composite UV-resistant agent.

[0111] Thirteen parts by weight of a styrene-maleic anhydride-acrylonitrile terpolymer with a weight average molecular weight of 4500 (the molar ratio of the repeating units of styrene, maleic anhydride and acrylonitrile was 4.5:2.7:2.8) were plasticized in a thin pass on an open mill at a plasticizing temperature of 152°C for 5.5 min. Then, the plasticized styrene-maleic anhydride-acrylonitrile terpolymer was added to a mixer, along with 100 parts by weight of natural rubber with a content of 91.8 wt% cis-1,4-polyisoprene and a Mooney viscosity [ML(1+4)100℃] of 65. The mixture was then mixed at 145℃ for 2.5 min. Next, 7 parts by weight of the above-mentioned inorganic-organic composite antioxidant, 5 parts by weight of activator (a mixture of zinc oxide and stearic acid, with a mass ratio of zinc oxide to stearic acid of 3.5:1), 25 parts by weight of silica with a particle size of 70 nm, and 2.5 parts by weight of N-phenyl-α-naphthylamine were added. The mixture was then mixed at 145℃ for 6 min. After internal mixing, the blend is mixed on an open mill, rolled, and then cut six times to form a sheet. 1.2 parts by weight of 2-mercaptobenzothiazole and 1.2 parts by weight of sublimed sulfur are added, and the sheet is cut six more times. Then, a triangular wrapping and thin-passing process is performed three times before sheeting, resulting in a sheet thickness of 6.5 mm. The open-milled rubber sheet is then placed on a flat vulcanizing machine for compression molding at a pressure of 13 MPa, a temperature of 152°C, and a time of 410 s, yielding the final UV-resistant rubber composite material.

[0112] The test results showed that the tensile strength of the UV-resistant rubber composite sample was 25.8 MPa, the elongation at break was 492%, and the tear strength was 66.9 KN / m. After aging, the tensile strength retention rate of the sample was 95.1%, the elongation at break retention rate was 93.5%, and the tear strength retention rate was 94.6%.

[0113] Example 3

[0114] First, 2 parts by weight of vinyltriethoxysilane were added to 60 parts by weight of ethanol solvent and stirred thoroughly at 45°C and 450 rpm for 30 minutes. Then, 3 parts by weight of 2-hydroxy-4-methoxybenzophenone were added, and stirring continued for 3 hours. Simultaneously, an ultrasonic device was used to assist dispersion and dissolution at a frequency of 60 kHz to obtain a mixed solution of UV inhibitors. Separately, 100 parts by weight of a solution with a specific surface area of ​​150 m² / g... 2 / g of cerium oxide nanospheres with an average particle size of 300nm and 2 parts by weight of vinyltriethoxysilane were placed in a vacuum high-speed mixer. The temperature was set at 90℃, the rotation speed at 350 rpm, and the vacuum degree at 0.065MPa. After mixing and modifying for 1.5h, the vacuum device was turned off. While stirring, the above-mentioned UV-resistant agent mixture was slowly sprayed into the mixture one by one. After all the mixture was sprayed, the vacuum device was turned on again and stirring was continued for 3h to ensure that the solvent was completely evaporated, thus obtaining a loaded inorganic-organic composite UV-resistant agent.

[0115] 15 parts by weight of a styrene-maleic anhydride-acrylonitrile terpolymer with a weight average molecular weight of 5000 (the molar ratio of the repeating units of styrene, maleic anhydride and acrylonitrile is 5:2.5:2.5) were plasticized in a thin pass on an open mill at a plasticizing temperature of 155℃ for 6 min. Then, the plasticized styrene-maleic anhydride-acrylonitrile terpolymer was added to a mixer, along with 100 parts by weight of natural rubber with a cis-1,4-polyisoprene content of 92 wt% and a Mooney viscosity [ML(1+4)100℃] of 65. The mixture was then mixed at 150℃ for 3 min. Next, 7.5 parts by weight of the above-mentioned inorganic-organic composite antioxidant, 6 parts by weight of activator (a mixture of zinc oxide and stearic acid, with a mass ratio of zinc oxide to stearic acid of 4:1), 30 parts by weight of calcium carbonate with a particle size of 50 μm, and 3 parts by weight of N-isopropyl-N'-phenyl-p-phenylenediamine were added. The mixture was then mixed at 150℃ for 6.5 min. After internal mixing, the blend is mixed on an open mill, rolled, and then cut six times to form a sheet. 1.5 parts by weight of N,N-tetramethyldithiocarboxylamine and 1.5 parts by weight of precipitated sulfur are added, and the sheet is cut six more times. Then, a triangular wrapping and thin-passing process is performed four times before sheeting, resulting in a sheet thickness of 7 mm. The open-milled rubber sheet is then placed on a flat vulcanizing machine for compression molding at a pressure of 15 MPa, a temperature of 155°C, and a time of 425 seconds, yielding the final UV-resistant rubber composite material.

[0116] The UV-resistant rubber composite material sample was tested and found to have a tensile strength of 26.4 MPa, an elongation at break of 475%, and a tear strength of 69.2 KN / m. After aging, the sample retained 96.1% of its tensile strength, 94.9% of its elongation at break, and 95.3% of its tear strength.

[0117] Example 4

[0118] First, 1 part by weight of γ-aminopropyltriethoxysilane and 1 part by weight of γ-glycidoxypropyltrimethoxysilane were added to 65 parts by weight of isopropanol solvent and stirred thoroughly at 48°C and 475 rpm for 35 min. Then, 2 parts by weight of 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole and 2 parts by weight of 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole were added, and stirring continued for 3.5 h. Simultaneously, an ultrasonic device was used to assist dispersion and dissolution at a frequency of 65 kHz to obtain a mixed solution of UV inhibitors. Separately, 100 parts by weight of a solution with a specific surface area of ​​175 m² was taken... 2 / g of cerium oxide nanospheres with an average particle size of 350nm and 2.5 parts by weight of γ-glycidyl etheroxypropyltrimethoxysilane were placed in a vacuum high-speed mixer. The temperature was set at 95℃, the rotation speed at 350 rpm, and the vacuum degree at 0.07MPa. After mixing and modification for 1.8h, the vacuum device was turned off. While stirring, the above-mentioned UV-resistant agent mixture was slowly sprayed into the mixture one by one. After all the mixture was sprayed, the vacuum device was turned on again and stirring was continued for 3.5h to ensure complete evaporation of the solvent, thus obtaining a loaded inorganic-organic composite UV-resistant agent.

[0119] 18 parts by weight of a styrene-maleic anhydride-acrylonitrile terpolymer with a weight average molecular weight of 5500 (the molar ratio of the repeating units of styrene, maleic anhydride and acrylonitrile is 5.5:2.3:2.2) were plasticized in a thin pass on an open mill at a plasticizing temperature of 158°C for 6.5 min. Then, the plasticized styrene-maleic anhydride-acrylonitrile terpolymer was added to a mixer, along with 100 parts by weight of natural rubber with a cis-1,4-polyisoprene content of 93 wt% and a Mooney viscosity [ML(1+4)100℃] of 65. The mixture was then kneaded at 155℃ for 3.5 min. Next, 9 parts by weight of the aforementioned inorganic-organic composite antioxidant, 6 parts by weight of the activator (a mixture of zinc oxide and stearic acid, with a mass ratio of zinc oxide to stearic acid of 4.5:1), 17 parts by weight of kaolin with a particle size of 8 μm, 18 parts by weight of talc with a particle size of 52 μm, 1.7 parts by weight of N-isopropyl-N'-phenyl-p-phenylenediamine, and 1.8 parts by weight of 2,2'-methylenebis(4-methyl-6-tert-butylphenol) were added. The mixture was then kneaded at 155℃ for 6.5 min. After internal mixing, the blend is mixed on an open mill, rolled, and then cut six times to form the rubber. Then, 1.4 parts by weight of N-cyclohexyl-2-benzothiazole sulfenamide, 1.4 parts by weight of N-tert-butyl-2-benzothiazole sulfenamide, 1.4 parts by weight of precipitated sulfur, and 1.4 parts by weight of insoluble sulfur are added. The mixture is then cut six times again, followed by triangular wrapping and thin-passing four times before sheeting. The sheet thickness is 7.5 mm. The open-milled rubber sheet is then placed on a flat vulcanizing machine for compression molding at a pressure of 17 MPa, a temperature of 158°C, and a time of 440 s, yielding the final UV-resistant rubber composite material.

[0120] The UV-resistant rubber composite material sample was tested and found to have a tensile strength of 27.5 MPa, an elongation at break of 465%, and a tear strength of 72.4 KN / m. After aging, the sample retained 97.2% of its tensile strength, 96.8% of its elongation at break, and 97.8% of its tear strength.

[0121] Example 5

[0122] First, 1 part by weight of bis-[γ-(triethoxysilyl)propyl]amine, 1 part by weight of γ-methacryloxypropyltrimethoxysilane, and 1 part by weight of γ-mercaptopropyltrimethoxysilane were added to 70 parts by weight of a mixed solvent (ethanol and isopropanol in a 1:1 mass ratio) and stirred thoroughly at 50°C, 500 rpm, and for 40 min. Then, 2 parts by weight of 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 1 part by weight of 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and 2 parts by weight of bis(2,2,6,6-tetramethyl-4-piperidine) sebacate were added, and stirring continued for 4 h. Simultaneously, an ultrasonic device was used to assist dispersion and dissolution at a frequency of 70 kHz to obtain a mixed solution of UV inhibitors. Separately, 100 parts by weight of a solution with a specific surface area of ​​200 m² was taken... 2 / g, spherical cerium oxide nanoparticles with an average particle size of 400nm, 1 part by weight of bis-[γ-(triethoxysilyl)propyl]amine, 1 part by weight of γ-methacryloxypropyltrimethoxysilane and 1 part by weight of γ-mercaptopropyltrimethoxysilane were placed in a vacuum high-speed mixer. The temperature was set to 100℃, the rotation speed was 400 rpm, and the vacuum degree was set to 0.08MPa. After mixing and modification for 2h, the vacuum device was turned off. While stirring, the above-mentioned UV-resistant agent mixture was slowly sprayed into the mixture one by one. After all the mixture was sprayed, the vacuum device was turned on again and stirring was continued for 4h to ensure that the solvent was completely evaporated, thus obtaining a loaded inorganic-organic composite UV-resistant agent.

[0123] Ten parts by weight of styrene-maleic anhydride-acrylonitrile terpolymer with a weight average molecular weight of 5000 (the molar ratio of the repeating units of styrene, maleic anhydride and acrylonitrile is 6:2:2) and ten parts by weight of styrene-maleic anhydride-acrylonitrile terpolymer with a weight average molecular weight of 6000 (the molar ratio of the repeating units of styrene, maleic anhydride and acrylonitrile is 6:2:2) were plasticized in a thin pass on an open mill at a plasticizing temperature of 160°C for 7 min. Then, the plasticized styrene-maleic anhydride-acrylonitrile terpolymer was added to a mixer, along with 100 parts by weight of natural rubber with a cis-1,4-polyisoprene content of 94 wt% and a Mooney viscosity [ML(1+4)100℃] of 65. The mixture was then mixed at 160℃ for 4 min. Next, 10 parts by weight of the above-mentioned inorganic-organic composite antioxidant, 8 parts by weight of activator (a mixture of zinc oxide and stearic acid with a mass ratio of 5:1), 20 parts by weight of barium sulfate with a particle size of 45 μm, 20 parts by weight of montmorillonite with a particle size of 90 μm, 2 parts by weight of 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and 2 parts by weight of N,N'-di(β-naphthyl)-p-phenylenediamine were added. The mixture was then mixed at 160℃ for 8 min. After internal mixing, the blend is mixed on an open mill, rolled, and then cut six times to form a new rubber sheet. Then, 1 part by weight of N-tert-butyl-2-benzothiazole sulfenamide, 1 part by weight of N,N'-dicyclohexyl-2-benzothiazole sulfenamide, 1 part by weight of precipitated sulfur, and 1 part by weight of sublimed sulfur are added. The mixture is then cut six times again, followed by a triangular wrapping and thin-passing process five times before sheeting. The sheet thickness is 8 mm. The open-milled rubber sheet is then placed on a flat vulcanizing machine for compression molding at a pressure of 20 MPa, a temperature of 160°C, and a time of 450 s, yielding the final UV-resistant rubber composite material.

[0124] The test results showed that the tensile strength of the UV-resistant rubber composite sample was 28.9 MPa, the elongation at break was 443%, and the tear strength was 76.8 KN / m. After aging, the tensile strength retention rate of the sample was 95.5%, the elongation at break retention rate was 97.7%, and the tear strength retention rate was 98.4%.

[0125] Comparative Example 1

[0126] Take 100 parts by weight of natural rubber with a cis-1,4-polyisoprene content of 91 wt% and a Mooney viscosity [ML(1+4)100℃] of 65, and mix at 140℃ for 2 min. Then add 4 parts by weight of activator (a mixture of zinc oxide and stearic acid, with a mass ratio of zinc oxide to stearic acid of 3:1), 20 parts by weight of carbon black, and 2 parts by weight of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, and mix at 140℃ for 5 min. After the internal mixing is completed, the blend is mixed on an open mill, rolled, and cut with six cuts to turn the rubber. Then add 1 part by weight of 2,2'-dithiodibenzothiazole and 1 part by weight of precipitated sulfur, cut with six cuts again, and then pass through a triangular wrapping machine three times to produce a sheet with a thickness of 6 mm. The open-mix rubber sheet is then placed on a flat vulcanizing machine for compression molding and vulcanization. The vulcanization pressure is 10 MPa, the vulcanization temperature is 150℃, and the vulcanization time is 400 s, resulting in the final UV-resistant rubber composite material.

[0127] The UV-resistant rubber composite material sample was tested and found to have a tensile strength of 20.3 MPa, an elongation at break of 522%, and a tear strength of 55.1 KN / m. After aging, the sample retained 82.2% of its tensile strength, 79.5% of its elongation at break, and 83.7% of its tear strength.

[0128] Comparative Example 2

[0129] First, 1 part by weight of bis-[γ-(triethoxysilyl)propyl]amine was added to 50 parts by weight of ethanol solvent and stirred thoroughly at 40°C and 400 rpm for 20 min. Then, 1 part by weight of 2-hydroxy-4-n-octyloxybenzophenone was added, and stirring continued for 2 h. Simultaneously, an ultrasonic device was used to assist dispersion and dissolution at a frequency of 50 kHz to obtain a mixed solution of UV inhibitors. Separately, 100 parts by weight of a solution with a specific surface area of ​​100 m² was taken... 2 / g of cerium oxide nanospheres with an average particle size of 200nm and 1 part by weight of bis-[γ-(triethoxysilyl)propyl]amine were placed in a vacuum high-speed mixer. The temperature was set to 80℃, the rotation speed was 300 rpm, and the vacuum degree was set to 0.05MPa. After mixing and modification for 1h, the vacuum device was turned off. While stirring, the above-mentioned UV-resistant agent mixture was slowly sprayed into the mixture one by one. After all the mixture was sprayed, the vacuum device was turned on again and stirring was continued for 2h to ensure that the solvent was completely evaporated, thus obtaining a loaded inorganic-organic composite UV-resistant agent.

[0130] Take 100 parts by weight of natural rubber with a cis-1,4-polyisoprene content of 91 wt% and a Mooney viscosity [ML(1+4)100℃] of 65, and mix at 140℃ for 2 min. Then add 5 parts by weight of the above-mentioned inorganic-organic composite antioxidant, 4 parts by weight of activator (a mixture of zinc oxide and stearic acid, with a mass ratio of zinc oxide to stearic acid of 3:1), 20 parts by weight of carbon black, and 2 parts by weight of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, and mix at 140℃ for 5 min. After the internal mixing is completed, the blend is mixed on an open mill, rolled, and cut with six cuts to turn the rubber. Then add 1 part by weight of 2,2'-dithiodibenzothiazole and 1 part by weight of precipitated sulfur, cut with six cuts again, and then pass through a triangular wrapping mill three times to produce a sheet with a thickness of 6 mm. The open-mix rubber sheet is then placed on a flat vulcanizing machine for compression molding and vulcanization. The vulcanization pressure is 10 MPa, the vulcanization temperature is 150℃, and the vulcanization time is 400 s, resulting in the final UV-resistant rubber composite material.

[0131] The test results showed that the tensile strength of the UV-resistant rubber composite sample was 21.5 MPa, the elongation at break was 518%, and the tear strength was 55.8 KN / m. After aging, the tensile strength retention rate of the sample was 89.3%, the elongation at break retention rate was 88.8%, and the tear strength retention rate was 89.5%.

[0132] Comparative Example 3

[0133] Ten parts by weight of a styrene-maleic anhydride-acrylonitrile terpolymer with a weight average molecular weight of 4000 (the molar ratio of the repeating units of styrene, maleic anhydride, and acrylonitrile was 4:3:3) were plasticized in a thin pass on an open mill at 150°C for 5 minutes. The plasticized styrene-maleic anhydride-acrylonitrile terpolymer was then added to an internal mixer, along with 100 parts by weight of natural rubber containing 91 wt% cis-1,4-polyisoprene and a Mooney viscosity [ML(1+4)100°C] of 65. The mixture was then mixed at 140°C for 2 minutes. Next, four parts by weight of an activator (a mixture of zinc oxide and stearic acid in a 3:1 mass ratio), 20 parts by weight of carbon black, and two parts by weight of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline were added, and the mixture was mixed at 140°C for 5 minutes. After internal mixing, the blend is mixed on an open mill, rolled, and then cut six times to form a sheet. One part by weight of 2,2'-dithiodibenzothiazole and one part by weight of precipitated sulfur are added, followed by another six-cutting process. The sheet is then passed through a triangular beading process three times to produce a sheet with a thickness of 6 mm. The open mill sheet is then placed on a flat vulcanizing machine for compression molding at a pressure of 10 MPa, a temperature of 150°C, and a time of 400 s, yielding the final UV-resistant rubber composite material.

[0134] The test results showed that the tensile strength of the UV-resistant rubber composite sample was 23.9 MPa, the elongation at break was 505%, and the tear strength was 61.6 KN / m. After aging, the tensile strength retention rate of the sample was 87.6%, the elongation at break retention rate was 87.0%, and the tear strength retention rate was 87.5%.

[0135] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A UV-resistant rubber composite material, characterized in that, By weight, the raw materials include: 100 parts natural rubber; 10-20 parts of styrene-maleic anhydride-acrylonitrile terpolymer; 5-10 parts of compound UV protectant; Activator 4-8 parts; 20-40 parts of reinforcing agent; Anti-aging agent 2-4 parts; Accelerator 1-2.8 parts; 1-2.8 parts of vulcanizing agent; The composite UV stabilizer includes nano-spherical cerium oxide and organic small molecule UV stabilizers and modifiers loaded on the surface of the nano-spherical cerium oxide, wherein the mass ratio of the nano-spherical cerium oxide, organic small molecule UV stabilizers and modifiers is 100:(1~5):(2~6).

2. The UV-resistant rubber composite material according to claim 1, characterized in that, The nano-spherical cerium oxide particles have a diameter of 200-400 nm and a specific surface area of ​​100-200 m². 2 / g.

3. The UV-resistant rubber composite material according to claim 1, characterized in that, The organic small molecule UV stabilizer is one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and bis(2,2,6,6-tetramethyl-4-piperidine) sebacate.

4. The UV-resistant rubber composite material according to claim 1, characterized in that, The modifier is one or more of the following: bis-[γ-(triethoxysilyl)propyl]amine, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane.

5. The UV-resistant rubber composite material according to claim 1, characterized in that, The weight-average molecular weight of the styrene-maleic anhydride-acrylonitrile terpolymer is 4000~6000; the molar ratio of the repeating unit corresponding to styrene, the repeating unit corresponding to maleic anhydride and the repeating unit corresponding to acrylonitrile in the styrene-maleic anhydride-acrylonitrile terpolymer is (4~6):(2~3):(2~3).

6. The UV-resistant rubber composite material according to claim 1, characterized in that, The activator is zinc oxide and stearic acid, and the mass ratio of zinc oxide to stearic acid is (3~5):1; The reinforcing agent is one or more of carbon black, silica, calcium carbonate, clay, talc, barium sulfate, and montmorillonite. The antioxidant is one or more of the following: 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, N-phenyl-α-naphthylamine, N-phenyl-β-naphthylamine, 2,6-di-tert-butyl-p-cresol, N-isopropyl-N'-phenyl-p-phenylenediamine, 2-mercaptobenzimidazole, N-isopropyl-N'-phenyl-p-phenylenediamine, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and N,N'-di(β-naphthyl)-p-phenylenediamine; The accelerator is one or more selected from 2,2'-dithiodibenzothiazole, 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole, diphenylguanidine, di-o-tolueneguanidine, N,N-tetramethyldisulfide disulfide carbonylamine, tetraethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, and N,N'-dicyclohexyl-2-benzothiazole sulfenamide. The vulcanizing agent is one or more of sublimed sulfur, precipitated sulfur, and insoluble sulfur.

7. A method for preparing the UV-resistant rubber composite material according to any one of claims 1 to 6, characterized in that, Includes the following steps: Natural rubber, styrene-maleic anhydride-acrylonitrile terpolymer, composite UV stabilizer, activator, reinforcing agent, antioxidant, accelerator and vulcanizing agent are mixed and vulcanized to obtain UV-resistant rubber composite material.

8. The preparation method according to claim 7, characterized in that, The composite UV protectant is prepared according to the following steps: i) Mix the organic small molecule UV stabilizer, some modifiers and solvents to obtain a UV stabilizer mixed solution; ii) Mix cerium oxide nanospheres with a portion of the modifier to obtain modified nanospheres; Steps i) and ii) are not in any particular order; iii) The UV-resistant agent mixture solution is sprayed onto the surface of the modified nanospheres, and the solvent is evaporated to obtain the composite UV-resistant agent.

9. The preparation method according to claim 8, characterized in that, The mass ratio of the modifier in step i) to the modifier in step ii) is 1:(0.5~2).

10. The preparation method according to claim 8, characterized in that, In step ii), the mixing temperature is 80~100℃, the vacuum degree is 0.05~0.08MPa, and the time is 1~2h.