Anti-aging agent for rubber and preparation method thereof

Abstract

The invention discloses an anti-aging agent for rubber and a preparation method of the anti-aging agent, and relates to the field of anti-aging agents. According to the invention, the grafted compound is compounded with the ultraviolet light absorber and the anti-ozone agent to generate a synergistic effect; the tea polyphenol provides hydrogen atoms through phenolic hydroxyl groups to be rapidly combined with free radicals, the tea polyphenol is preferentially oxidized, the free radical chain reaction is terminated, and the antiozonant captures the free radicals through amino groups; the ultraviolet light absorber captures free radicals induced by ultraviolet light, converts light energy into heat energy to be released, blocks a photo-oxidation chain reaction, forms a broad-spectrum covered anti-oxidation network aiming at different free radical types, and enhances the anti-aging performance of the rubber; the tea polyphenol is fixed in the channels of the modified silicon dioxide through hydrogen bonds, so that the tea polyphenol is loaded on the silicon dioxide to form a grafted compound with a stable structure, thereby delaying the aging and degradation of the rubber.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-aging agents, in particular to an anti-aging agent for rubber and a preparation method thereof. Background Art

[0002] Due to its unique elasticity, wear resistance, insulation and corrosion resistance, rubber is widely used in human production and life. In the industrial construction field, it is used for conveyor belts, sealing gaskets, and anti-seepage layers; in the medical device field, it is used for artificial organs, medical gloves, catheters, etc.; in the military equipment field, it is used for tires, aerospace seals, etc.

[0003] During processing, storage, and use, rubber is subject to a combination of internal and external factors, which can lead to problems such as decreased strength, loss of elasticity, and reduced insulation. These are all signs of rubber aging. Double bonds or carbon-hydrogen bonds in rubber molecular chains react easily with oxygen and ozone, generating free radicals and initiating chain reactions. This process can lead to molecular chain breakage or excessive cross-linking, making the rubber hard, brittle, or sticky, and degrading its mechanical properties. Rubber is also affected by environmental factors such as light, heat, mechanical stress, and metal ions, which catalyze the generation of free radicals. Therefore, anti-aging agents are needed to prevent free radical reactions.

[0004] Common antioxidants include amine antioxidants, phenolic antioxidants, etc., among which phenolic antioxidants are non-polluting antioxidants; although the amine antioxidants in the prior art have outstanding protective effects, they generally have pollution problems, which makes them unable to be used in white or light-colored rubber products. Although phenolic antioxidants are non-polluting, their antioxidant and ozone resistance properties are far inferior to those of amines, and their protective effects are relatively weak. Therefore, in view of the above-mentioned defects in the prior art, it is necessary to prepare an antioxidant for rubber that has good effects and can avoid pollution. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing an anti-aging agent for rubber, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing an anti-aging agent for rubber, the production process comprising: uniformly mixing a grafted composite, an acetone solution, a benzotriazole ultraviolet absorber, and a diphenylamine derivative antiozonant to obtain the anti-aging agent.

[0007] In the above technical solution, the anti-aging performance of the rubber is enhanced by compounding the grafted compound, the ultraviolet absorber and the antiozonant; and the use of acetone solution as a dispersant enables better mixing and enhances the uniformity of the mixture.

[0008] Furthermore, the preparation process of the grafted composite is as follows:

[0009] Step (1): 3-aminopropyltriethoxysilane is mixed with mesoporous silica, toluene is added, and the pH is adjusted to 4-6 using acetic acid solution, and the mixture is stirred at a stirring rate of 200-400 rpm for 10-30 minutes, reacted at a reaction temperature of 40-60° C. for 4-6 hours, centrifuged at a rate of 1000-1500 rpm / min for 10-20 minutes, and vacuum dried at 60-70° C. for 1-2 hours to obtain modified silica;

[0010] Step (2): dissolving tea polyphenols in an ethanol solution and reacting with modified silica at a reaction temperature of 40 to 60° C. and a stirring rate of 200 to 300 rpm for 40 to 60 minutes. After the reaction is completed, vacuum drying is performed at 60 to 70° C. for 1 to 2 hours to obtain a grafted composite.

[0011] In the above technical solution, 3-aminopropyltriethoxysilane is first used to modify mesoporous silica so that its surface has amino active groups. Tea polyphenols are fixed in the pores of the modified silica through hydrogen bonds, so that the tea polyphenols are loaded on the silica, enhancing the dispersibility and thermal stability with the antioxidant; the surface of tea polyphenols is rich in phenolic hydroxyl groups, which terminate the free radical chain reaction during the rubber oxidation process and delay the aging and degradation of the rubber.

[0012] The present invention selects toluene as a dispersant and an acetic acid solution to adjust pH, thereby promoting uniform dispersion of 3-aminopropyltriethoxysilane in the mesoporous silica. Furthermore, toluene can inhibit excessive hydrolysis of 3-aminopropyltriethoxysilane to generate siloxane oligomers.

[0013] Furthermore, the preparation process of the anti-aging agent is as follows:

[0014] The grafted composite was vacuum dried at 70-80°C for 2-3h, acetone solution was used as a dispersant, ultraviolet absorber and antiozonant were added, and ultrasonic dispersion was carried out at room temperature for 30-60min. At the same time, nitrogen atmosphere was used for protection, with a nitrogen flow rate of 5-10L / min and a pressure of 0.01-0.03MPa to prepare an anti-aging agent.

[0015] Furthermore, the components of the grafted composite include: tea polyphenols, 3-aminopropyltriethoxysilane, and mesoporous silica.

[0016] Furthermore, the anti-aging agent includes the following components by mass: 10 to 20 parts of grafted composite, 5 to 15 parts of ultraviolet absorber, 5 to 15 parts of antiozonant, and 3 to 5 parts of acetone solution.

[0017] Furthermore, the ultraviolet absorber is 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole (UV-327), and the antiozonant is 4,4'-di(phenylisopropyl)diphenylamine (AO-445).

[0018] Furthermore, the concentration of the acetone solution is 25% to 30%, the concentration of the acetic acid solution is 30% to 36%, and the concentration of the ethanol solution is 70% to 75%.

[0019] Furthermore, the mass ratio of the acetone solution, toluene, acetic acid solution and ethanol solution is (3-4):3:2:10.

[0020] Furthermore, the specific component of tea polyphenols is epigallocatechin gallate (EGCG).

[0021] Furthermore, the mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica is (1-2):100.

[0022] Furthermore, the mass ratio of tea polyphenols to modified silicon dioxide is 1:(1-2).

[0023] An application of an anti-aging agent for rubber comprises the following steps:

[0024] S1: Plasticate the styrene-butadiene rubber on a cold roll mill until the rolls are covered, then adjust the roll distance to 4-6 mm to form an appropriate amount of bulk rubber, add stearic acid, white carbon black, and coupling agent in sequence, and after the material is completely absorbed, form a triangular bag and roll it 6-8 times, and sheet the mixed rubber A and cool it;

[0025] S2: adding talcum powder, silane coupling agent and zinc stearate to the antioxidant, heating and stirring to obtain rubber mix B;

[0026] S3: putting the rubber mix A in step S1 on a cold roller mill for mixing, adding the rubber mix B in S2, and after the mixing is completed, making a thin triangle bag and rolling it 6 to 8 times, and the rubber mix C is sheeted and cooled;

[0027] S4: After the rubber mix is ​​left at room temperature for 24 to 26 hours, a vulcanizing agent is added and pre-vulcanized in a small mold. The pre-vulcanized rubber is then quickly transferred to a larger mold for vulcanization to produce styrene-butadiene rubber products.

[0028] Furthermore, the process of S2 is as follows:

[0029] After talcum powder is vacuum dried at 90-100° C. for 2-3 hours, it is mixed with an anti-aging agent, and a silane coupling agent and zinc stearate are added. The mixing temperature is 60-90° C. and the mixing is carried out for 1-3 hours to prepare a rubber compound B.

[0030] In the above technical solution, an anti-aging agent is mixed with zinc stearate to enhance the binding performance of the anti-ozonant and the filler and reduce the interface defects of the mixture; talcum powder is used as a filler in the rubber preparation process, and its dispersibility and fluidity are enhanced during the mixing process, thereby improving the tear resistance of the rubber; a silane coupling agent is used to establish a molecular bridge between organic and inorganic substances through siloxane bonds, significantly improving the interfacial bonding strength; and a vulcanizing agent is added in step S4 to effectively inhibit the oxidative degradation of the rubber caused by oxygen, heat, light and mechanical stress, thereby extending the service life of the product.

[0031] Furthermore, the styrene-butadiene rubber product includes the following components by weight: 100-120 parts of styrene-butadiene rubber, 30-40 parts of white carbon black, 1-3 parts of stearic acid, 2-5 parts of coupling agent, 2-6 parts of anti-aging agent, 1-3 parts of vulcanizing agent, 10-15 parts of talc powder, 1-2 parts of silane coupling agent, and 1-2 parts of zinc stearate.

[0032] Furthermore, the silane coupling agent is KH-560.

[0033] Furthermore, the vulcanization treatment parameters in step S4 are: vulcanization pressure 15-25 MPa, vulcanization temperature 150-170° C., and vulcanization time 15-30 min.

[0034] Furthermore, the vulcanizing agent is N-cyclohexyl-2-benzothiazole sulfenamide, and the added amount is 1.5% to 2% of the mass of the styrene-butadiene rubber.

[0035] Furthermore, the coupling agent is Si69.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The present invention provides a method for preparing an anti-aging agent for rubber, which uses modified silica as a carrier, tea polyphenols as a basic material for stabilizing free radicals, and 3-aminopropyltriethoxysilane to introduce amino active groups on the surface of mesoporous silica to obtain modified silica, thereby activating its surface.

[0038] 2. The present invention grafts tea polyphenols onto the surface of modified silica by chemical bonding through in-situ modification. The rich phenolic hydroxyl structure on the surface of tea polyphenols effectively captures active free radicals generated by oxidation of rubber molecules, causing them to combine to form stable compounds, thereby slowing down the aging rate of rubber and giving it better anti-aging properties. By adding talc as a filler, its dispersibility and fluidity are enhanced during the mixing process, thereby improving the tear resistance of the rubber.

[0039] 3. The present invention produces a synergistic effect by adding a UV absorber, an antiozonant and a grafted composite prepared with tea polyphenols. Tea polyphenols are natural antioxidants. Compared with existing amine anti-aging agents, they are not only environmentally friendly, but also have excellent free radical stabilization effects. Tea polyphenols provide hydrogen atoms through phenolic hydroxyl groups to quickly combine with free radicals, are preferentially oxidized, and terminate the free radical chain reaction.

[0040] 4. The present invention uses AO-445 to capture free radicals through amino groups, and forms a broad-spectrum antioxidant network with tea polyphenols for different types of free radicals, thereby enhancing the anti-aging properties of rubber; the ultraviolet absorber captures ultraviolet-induced free radicals, converts light energy into heat energy release, blocks the photooxidation chain reaction, prevents the rubber surface from powdering, fading, and cracking, and maintains the appearance and mechanical properties of the rubber.

[0041] 5. The present invention uses an antiozonant in the compounding to block the attack of ozone on the unsaturated rubber molecular chain. The compounding synergistically forms a multiple protection barrier to jointly cope with the superimposed effects of ultraviolet rays, ozone, and thermal oxidative aging during dynamic use, thereby prolonging the service life of the rubber. DETAILED DESCRIPTION

[0042] The technical solutions in the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] In the following specific embodiments:

[0044] The "parts" mentioned below are parts by mass;

[0045] The concentration of the acetone solution described below is 25%; the concentration of the acetic acid solution is 36%; the concentration of the ethanol solution is 75%;

[0046] Mesoporous silica, with an average mesopore size of 6 nm and an average particle size of 5 μm;

[0047] Carbon nanotubes, with an average diameter of 2 nm and an average length of 30 μm;

[0048] Example 1: A method for preparing an anti-aging agent for rubber, the preparation process is as follows:

[0049] The grafted composite was vacuum dried at 71°C for 2 hours, acetone solution was used as a dispersant, UV-327 and AO-445 were added, and ultrasonic dispersion was carried out at room temperature for 30 minutes. At the same time, nitrogen atmosphere was used for protection, the nitrogen flow rate was 5 L / min, and the pressure was 0.01 MPa to prepare an anti-aging agent; the mass components of the anti-aging agent are as follows: 10 parts of the grafted composite, 3 parts of the acetone solution, 5 parts of UV-327, and 5 parts of AO-445.

[0050] The preparation process of the grafted composite is as follows:

[0051] Step (1): 3-aminopropyltriethoxysilane was mixed with mesoporous silica, 3 parts of toluene was added, and the pH was adjusted to 4 using 2 parts of acetic acid solution. The mixture was stirred at a stirring rate of 200 rpm for 10 minutes, reacted at a reaction temperature of 40°C for 4 hours, centrifuged at a rate of 1000 rpm / min for 10 minutes, and vacuum dried at 60°C for 1 hour to obtain modified silica; the mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica was 1.5:100;

[0052] Step (2): EGCG was mixed with 10 parts of ethanol solution and reacted with modified silica at a reaction temperature of 40°C and a stirring rate of 200 rpm for 40 minutes. After the reaction was completed, the mixture was vacuum dried at 60°C for 1 hour to obtain a grafted composite; the mass ratio of EGCG to modified silica was 1:1.

[0053] Example 2: A method for preparing an anti-aging agent for rubber, the preparation process is as follows:

[0054] The grafted composite was vacuum dried at 75°C for 2.5 hours, acetone solution was used as a dispersant, UV-327 and AO-445 were added, and ultrasonic dispersion was carried out at room temperature for 40 minutes. At the same time, nitrogen atmosphere was used for protection, the nitrogen flow rate was 5.5 L / min, and the pressure was 0.02 MPa to prepare an anti-aging agent; the mass components of the anti-aging agent are as follows: 15 parts of the grafted composite, 3.5 parts of acetone solution, 5.8 parts of UV-327, and 8.5 parts of AO-445.

[0055] The preparation process of the grafted composite is as follows:

[0056] Step (1): 3-aminopropyltriethoxysilane was mixed with mesoporous silica, 3 parts of toluene was added, and the pH was adjusted to 4 using 2 parts of acetic acid solution. The mixture was stirred at a stirring rate of 200 rpm for 10 minutes, reacted at a reaction temperature of 40°C for 4 hours, centrifuged at a rate of 1300 rpm / min for 15 minutes, and vacuum dried at 65°C for 1.5 hours to obtain modified silica; the mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica was 1.2:100;

[0057] Step (2): EGCG was mixed with 10 parts of ethanol solution and reacted with modified silica at a reaction temperature of 50°C and a stirring rate of 250 rpm for 50 minutes. After the reaction was completed, the mixture was vacuum dried at 65°C for 1.5 hours to obtain a grafted composite; the mass ratio of EGCG to modified silica was 1:1.5.

[0058] Example 3: A method for preparing an anti-aging agent for rubber, the preparation process is as follows:

[0059] The grafted composite was vacuum dried at 75°C for 2.5 hours, acetone solution was used as a dispersant, UV-327 and AO-445 were added, and ultrasonic dispersion was carried out at room temperature for 40 minutes. At the same time, nitrogen atmosphere protection was used with a nitrogen flow rate of 7 L / min and a pressure of 0.02 MPa to prepare an anti-aging agent; the mass components of the anti-aging agent are as follows: 15 parts of the grafted composite, 4 parts of the acetone solution, 10 parts of UV-327, and 10 parts of AO-445.

[0060] The preparation process of the grafted composite is as follows:

[0061] Step (1): 3-aminopropyltriethoxysilane was mixed with mesoporous silica, 3 parts of toluene was added, and the pH was adjusted to 6 using 2 parts of acetic acid solution. The mixture was stirred at a stirring rate of 400 rpm for 30 minutes, reacted at a reaction temperature of 60°C for 6 hours, centrifuged at a rate of 1500 rpm / min for 20 minutes, and vacuum dried at 70°C for 2 hours to obtain modified silica; the mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica was 2:100;

[0062] Step (2): EGCG was mixed with 10 parts of ethanol solution and reacted with modified silica at a reaction temperature of 60°C and a stirring rate of 300 rpm for 60 minutes. After the reaction was completed, the mixture was vacuum dried at 70°C for 2 hours to obtain a grafted composite; the mass ratio of EGCG to modified silica was 1:2.

[0063] Comparative Example 1: A method for preparing an anti-aging agent for rubber, the preparation process is as follows:

[0064] The grafted composite was vacuum dried at 80°C for 3 hours, acetone solution was used as a dispersant, UV-327 and AO-445 were added, and ultrasonic dispersion was carried out at room temperature for 60 minutes. At the same time, nitrogen atmosphere was used for protection, the nitrogen flow rate was 10 L / min, and the pressure was 0.03 MPa to prepare an anti-aging agent; the mass components of the anti-aging agent are as follows: 15 parts of the grafted composite, 3 parts of the acetone solution, 10 parts of UV-327, and 10 parts of AO-445.

[0065] The grafted support used in this comparative example is carbon nanotubes.

[0066] The preparation process of the grafted composite is as follows:

[0067] Step (1): 3-aminopropyltriethoxysilane was mixed with carbon nanotubes, 2 parts of toluene were added, and the pH was adjusted to 4.5 using 2 parts of acetic acid solution. The mixture was stirred at a stirring rate of 300 rpm for 20 minutes, reacted at a reaction temperature of 50°C for 4.5 hours, centrifuged at a rate of 1300 rpm / min for 15 minutes, and vacuum dried at 65°C for 1.5 hours to obtain modified carbon nanotubes; the mass ratio of 3-aminopropyltriethoxysilane to modified carbon nanotubes was 2:1;

[0068] Step (2): EGCG was mixed with 10 parts of ethanol solution and reacted with the modified carbon nanotubes at a reaction temperature of 50°C and a stirring rate of 250 rpm for 50 minutes. After the reaction was completed, the mixture was vacuum dried at 65°C for 2 hours to obtain a grafted composite; the mass ratio of EGCG to the modified carbon nanotubes was 1:2.

[0069] Comparative Example 2: In this comparative example, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) was used as a compound anti-aging agent.

[0070] A method for preparing an anti-aging agent for rubber, the preparation process is as follows:

[0071] The grafted complex was vacuum dried at 75°C for 2.5 hours, acetone solution was used as a dispersant, 6PPD was added, and ultrasonic dispersion was carried out at room temperature for 50 minutes. At the same time, nitrogen atmosphere protection was used with a nitrogen flow rate of 7 L / min and a pressure of 0.02 MPa to prepare an anti-aging agent; the mass components of the anti-aging agent are as follows: 20 parts of the grafted complex, 5 parts of the acetone solution, and 15 parts of 6PPD.

[0072] The preparation process of the grafted composite is as follows:

[0073] Step (1): 3-aminopropyltriethoxysilane was mixed with mesoporous silica, 2 parts of toluene were added, the pH was adjusted to 6 with acetic acid solution, the mixture was stirred at a stirring rate of 400 rpm for 30 minutes, the reaction temperature was 60°C for 6 hours, the mixture was centrifuged at a rate of 1500 rpm / min for 20 minutes, and vacuum dried at 70°C for 2 hours to obtain modified silica; the mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica was 2:100;

[0074] Step (2): EGCG was mixed with 10 parts of ethanol solution and reacted with modified silica at a reaction temperature of 60°C and a stirring rate of 300 rpm for 60 minutes. After the reaction was completed, the mixture was vacuum dried at 70°C for 2 hours to obtain a grafted composite; the mass ratio of EGCG to modified silica was 1:2.

[0075] Comparative Example 3: In this comparative example, AO-445 was used as a compound anti-aging agent.

[0076] A method for preparing an anti-aging agent for rubber, the preparation process is as follows:

[0077] The grafted composite was vacuum dried at 80°C for 3 hours, acetone solution was used as a dispersant, AO-445 was added, and ultrasonic dispersion was carried out at room temperature for 60 minutes. At the same time, nitrogen atmosphere protection was used with a nitrogen flow rate of 10 L / min and a pressure of 0.03 MPa to prepare an anti-aging agent; the mass components of the anti-aging agent are as follows: 20 parts of the grafted composite, 5 parts of the acetone solution, and 20 parts of AO-445.

[0078] The preparation process of the grafted composite is as follows:

[0079] Step (1): 3-aminopropyltriethoxysilane was mixed with mesoporous silica, 2 parts of toluene were added, the pH was adjusted to 6 with acetic acid solution, the mixture was stirred at a stirring rate of 400 rpm for 30 minutes, the reaction temperature was 60°C for 6 hours, the mixture was centrifuged at a rate of 1500 rpm / min for 20 minutes, and vacuum dried at 70°C for 2 hours to obtain modified silica; the mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica was 1.5:100;

[0080] Step (2): EGCG was mixed with 10 parts of ethanol solution and reacted with modified silica at a reaction temperature of 60°C and a stirring rate of 250 rpm for 50 minutes. After the reaction was completed, the mixture was vacuum dried at 70°C for 2 hours to obtain a grafted composite; the mass ratio of EGCG to modified silica was 1:2.

[0081] Comparative Example 4: In this comparative example, no other anti-aging agent was used to compound with the tea polyphenol grafted complex to prepare the anti-aging agent.

[0082] A method for preparing an anti-aging agent for rubber, the preparation process is as follows:

[0083] The grafted composite was vacuum dried at 80°C for 2.5 hours, and acetone solution was used as a dispersant. Ultrasonic dispersion was carried out at room temperature for 50 minutes, and nitrogen atmosphere was used for protection at a nitrogen flow rate of 7 L / min and a pressure of 0.02 MPa to prepare an anti-aging agent. The mass components of the anti-aging agent are as follows: 70 parts of the grafted composite and 5 parts of the acetone solution.

[0084] The preparation process of the grafted composite is as follows:

[0085] Step (1): 3-aminopropyltriethoxysilane was mixed with mesoporous silica, 2 parts of toluene were added, the pH was adjusted to 6 with acetic acid solution, the mixture was stirred at a stirring rate of 300 rpm for 20 minutes, the reaction temperature was 60°C for 5 hours, the mixture was centrifuged at a rate of 1300 rpm / min for 15 minutes, and vacuum dried at 60°C for 2 hours to obtain modified silica; the mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica was 2:100;

[0086] Step (2): EGCG was mixed with 10 parts of ethanol solution and reacted with modified silica at a reaction temperature of 40°C and a stirring rate of 200 rpm for 40 minutes. After the reaction was completed, the mixture was vacuum dried at 60°C for 2 hours to obtain a grafted composite; the mass ratio of EGCG to modified silica was 1:1.

[0087] experiment:

[0088] Take the rubber anti-aging agents obtained in Examples 1-3 and Comparative Examples 1-4 to prepare samples, test their properties and record the test results:

[0089] Thermal Oxidative Aging Resistance Test: According to ASTM D3895, the rubber samples were placed in a thermal oxidative aging chamber at 200°C and an oxygen flow rate of 50 mL / min for oxidation testing, and the oxidation induction time (OIT) was measured.

[0090] Anti-ultraviolet aging performance test: Refer to ASTM G154-16, use a UV aging tester to simulate ultraviolet radiation, irradiate continuously for 20 days, and measure the ultraviolet absorbance by spectrophotometer.

[0091] Ozone aging resistance test: Refer to GB / T 7762 standard, expose in an ozone aging chamber with an ozone concentration of 50-100pphm and a temperature of 40°C, and measure its resistance time.

[0092] Performance comparison table

[0093]

[0094] According to the data in the above table, we can clearly draw the following conclusions:

[0095] The rubber anti-aging agents obtained in Examples 1-3 were compared with the anti-aging agents obtained in Comparative Examples 1-4. The test results show that:

[0096] Compared with the comparative example, the rubber antioxidants obtained in Examples 1-3 have a long anti-oxidation time, a high ultraviolet absorption rate, and a long resistance time to the reaction with ozone.

[0097] Compared with Example 1, the antioxidant prepared by using carbon nanotubes as a carrier for loading tea polyphenols in Comparative Example 1 has lower antioxidant properties, ultraviolet absorption capacity, and ozone tolerance than those in Example 1. It can be seen that the antioxidant prepared by using carbon nanotubes as a loading material and adding tea polyphenols to obtain a grafted composite has good coloring properties, but the antioxidant prepared by not using pre-treated silica to add tea polyphenols has strong anti-aging ability.

[0098] Compared with Example 1, the anti-aging agent obtained in Comparative Example 2, which is compounded with 6PPD, has lower antioxidant properties, ultraviolet absorption capacity, and ozone tolerance than those in Example 1. It can be seen that the anti-aging agent compounded with 6PPD has lower anti-aging performance.

[0099] Compared with Example 1, the anti-aging agent in Comparative Example 3 is compounded with AO-445 and the grafted complex, and has better antioxidant properties and ozone tolerance, and the ultraviolet absorption capacity is significantly reduced. It can be seen that the anti-aging agent compounded with AO-445 and the grafted complex, without being compounded with tea polyphenols, has a significantly reduced ultraviolet absorption rate and low resistance to light, which is not conducive to prolonging the service life of the rubber.

[0100] Compared with Example 1, in Comparative Example 4, no compounding material is used, and the antioxidant ability, UV absorption ability, and ozone resistance are significantly reduced. It can be seen that the anti-aging ability without using compounding materials is not as good as the effect of using grafted composites, UV absorbers, and antiozonants in the present invention.

[0101] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing an anti-aging agent for rubber, characterized in that: The preparation process is as follows: vacuum drying the grafted composite, using acetone solution as a dispersant, adding an ultraviolet absorber and an antiozonant, ultrasonically dispersing at room temperature, and using nitrogen atmosphere for protection to prepare the anti-aging agent.

2. The method for preparing an anti-aging agent for rubber according to claim 1, wherein: The components of the grafted composite include: tea polyphenols, 3-aminopropyltriethoxysilane and mesoporous silica.

3. The method for preparing an anti-aging agent for rubber according to claim 1, wherein: The preparation process of the grafted composite is as follows: Step (1): 3-aminopropyltriethoxysilane is mixed with mesoporous silica, toluene is added, pH is adjusted with acetic acid solution, mixed, heated for reaction, centrifuged, and vacuumed to obtain modified silica; Step (2): dissolving tea polyphenols in an ethanol solution, reacting with modified silica, heating the reaction, and vacuum drying to obtain a grafted composite.

4. The method for preparing an anti-aging agent for rubber according to claim 1, wherein: The anti-aging agent comprises the following components by weight: 10 to 20 parts of a grafted composite, 5 to 15 parts of an ultraviolet absorber, 5 to 15 parts of an antiozonant, and 3 to 5 parts of an acetone solution.

5. The method for preparing an anti-aging agent for rubber according to claim 1, wherein: The vacuum drying process conditions are: drying at 70-80° C. for 2-3 hours; the ultrasonic dispersion process conditions are: dispersion at 20-40 kHz for 30-60 minutes, a nitrogen protection flow rate of 5-10 L / min, and a pressure of 0.01-0.03 MPa.

6. The method for preparing an anti-aging agent for rubber according to claim 3, wherein: In step (1), the mixing rate is 200-400 rpm, and the centrifugal process conditions are: centrifugation at a rate of 1000-1500 rpm / min for 10-20 min; the drying process conditions are: vacuum drying at 60-70° C. for 1-2 h; and the heating reaction process conditions in step (2) are: stirring at a reaction temperature of 40-60° C. at a stirring rate of 200-300 rpm for 40-60 min.

7. The method for preparing an anti-aging agent for rubber according to claim 3, characterized in that: The mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica is (1-2):

100.

8. The method for preparing an anti-aging agent for rubber according to claim 3, wherein: The mass ratio of tea polyphenols to modified silicon dioxide is 1:(1-2).

9. The method for preparing an anti-aging agent for rubber according to claim 1, wherein: The ultraviolet absorber is 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole; the antiozonant is 4,4'-di(phenylisopropyl)diphenylamine; and the tea polyphenol is epigallocatechin gallate.

10. An anti-aging agent for rubber, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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