Weather-resistant rubber for plastic track and preparation method of weather-resistant rubber

Abstract

The invention discloses weather-resistant rubber for a plastic track and a preparation method of the weather-resistant rubber, and belongs to the technical field of rubber composite materials. The weather-resistant rubber for the plastic track comprises the following raw materials in parts by weight: 70-80 parts of ethylene propylene diene monomer, 20-30 parts of filler, 5-10 parts of a softening agent, 1-3 parts of a vulcanizing agent, 1-3 parts of an accelerant, 1-3 parts of a coupling agent and 0.6-1.2 parts of an anti-aging agent. The filler is highly dispersed and stably exists in a rubber matrix under the action of the coupling agent; according to the present invention, the anti-aging agent containing the aromatic amine structure and the benzophenone structure, the ethylene propylene diene monomer and the filler are grafted and cross-linked through the chemical action so as to form the stable spatial network structure, such that the anti-aging agent stably exists in the rubber matrix, and is not easily affected by the external environment to migrate so as to provide the good anti-aging effect; and the rubber material is protected, and the service life of the rubber material is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of rubber composite materials, and in particular, relates to a weather-resistant rubber for a plastic runway and a preparation method thereof. Background Art

[0002] EPDM rubber materials are widely used in plastic running tracks, leisure trails, artificial turf filling and other fields. The main chain of EPDM rubber is composed of chemically stable saturated hydrocarbons, and only contains unsaturated double bonds in the side chains. Therefore, it has good chemical resistance, electrical insulation, impact elasticity, low temperature performance, low density, high filling, hot water resistance and water vapor resistance, etc. It is an ideal material for plastic running tracks.

[0003] However, the plastic track is in an open-air environment and is exposed to sunlight and high temperature for a long time. Therefore, the plastic track is easily affected by ultraviolet rays and high temperatures. The tensile strength and other properties will decrease, the weather resistance will deteriorate, the service life will be greatly shortened, and it may even cause safety accidents. Adding antioxidants is the most convenient and effective way to delay the aging of rubber, but most antioxidants are easy to migrate out of the rubber matrix in a high temperature environment. Therefore, it is extremely important to improve and maintain the anti-aging properties of rubber used for plastic tracks. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a weather-resistant rubber for a plastic runway and a preparation method thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A weather-resistant rubber for a plastic track comprises the following raw materials in parts by weight: 70-80 parts of EPDM rubber, 20-30 parts of filler, 5-10 parts of softener, 1-3 parts of vulcanizer, 1-3 parts of accelerator, 1-3 parts of coupling agent and 0.6-1.2 parts of antioxidant.

[0006] Furthermore, the filler is one or more of fumed silica, nano titanium dioxide, talcum powder, heavy calcium carbonate, and carbon black.

[0007] Furthermore, the softener is one or more of white oils.

[0008] Furthermore, the vulcanizing agent is one or more of diisopropylbenzene peroxide, di-tert-butyl peroxide, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 1,4-di-tert-butylperoxyisopropylbenzene, and tert-butyl perbenzoate.

[0009] Furthermore, the accelerator is one or both of triallyl cyanurate and triallyl isocyanurate.

[0010] Furthermore, the coupling agent is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, and 3-(methacryloyloxy)propyltrimethoxysilane.

[0011] The silaneoxy groups in the coupling agent are hydrolyzed and condensed to form Si-OH and Si-O-Si. The hydroxyl groups in Si-OH can form chemical bonds with the hydroxyl groups in the filler to form covalent bonds, and the surface energy of the filler is greatly reduced under the action of the coupling agent, and the compatibility between the filler and the remaining raw materials is greatly increased. In addition, the coupling agents are all coupling agents containing carbon-carbon double bonds, so the surface of the filler contains abundant carbon-carbon double bonds, which can produce chemical reactions with the carbon-carbon double bonds of the EPDM side chain under the action of peroxide vulcanizers and accelerators, and the filler can be highly dispersed in the rubber for plastic runways, giving full play to the effects of reinforcement and anti-aging. At the same time, the carbon-carbon double bonds on the surface of the filler can also produce chemical reactions with the double bonds on the surface of the antioxidant, and the chemical reaction improves the dispersibility and stability of the antioxidant, and thus makes the antioxidant of the present invention difficult to migrate out of the rubber matrix, and the antioxidant can protect the rubber from aging due to high temperature and ultraviolet rays for a long time, greatly extending the service life of the rubber.

[0012] Furthermore, the antioxidant is prepared by the following steps: S1. Under nitrogen protection, add 2,4-dihydroxybenzophenone, triethylamine and chloroform into a dry three-necked flask, stir and heat to 40°C until dissolved, then continue to heat to 80°C, then slowly add 3-chloro-2-chloromethyl propylene, keep warm for 3 hours after the addition is complete, distill under reduced pressure after the reaction is completed, purify by column chromatography (the eluent is selected from a mixed solvent of benzene and ethyl acetate, and the volume ratio of benzene and ethyl acetate is 8:2), and distill under reduced pressure to obtain intermediate 1; the amount ratio of 2,4-dihydroxybenzophenone, 3-chloro-2-chloromethyl propylene, triethylamine and chloroform is 45.8g:23.1mL:34mL:240mL; Under triethylamine and heating conditions, the molar ratio of 2,4-dihydroxybenzophenone and 3-chloro-2-chloromethylpropene is controlled to be 1.05-1.1:1, then -OH of 2,4-dihydroxybenzophenone and -Cl of 3-chloro-2-chloromethylpropene react, and the reaction process is as follows: S2. Add p-aminodiphenylamine, triethylamine and DMSO (dimethyl sulfoxide) into a dry three-necked flask under nitrogen protection, stir to dissolve and then heat to 90°C, then slowly add the mixed solution of intermediate 1 and DMSO, keep warm for 3 hours after the addition is completed, cool to room temperature after the reaction is completed, and distill under reduced pressure to obtain an antioxidant; the dosage ratio of p-aminodiphenylamine, intermediate 1, triethylamine and DMSO is 19.5mL:30.3g:17mL:220mL.

[0013] Triethylamine is used as an acid-binding agent, and the molar ratio of p-aminodiphenylamine to intermediate 1 is controlled to be 1.1-1.2:1. Then, -NH2 of p-aminodiphenylamine and -Cl of intermediate 1 undergo a substitution reaction under heating. The reaction process is as follows: The antioxidant contains aromatic amine structure and benzophenone structure. The aromatic amine structure provides active hydrogen to terminate the peroxy radicals, alkoxy radicals and hydroxyl radicals generated during rubber aging, generating hydroperoxides, alcohols and water, thereby weakening the reaction between the free radicals and the rubber molecular chain; the benzophenone structure can absorb ultraviolet light, transform from the ground state to the excited state, and then the excited state energy dissipates in the form of secondary radiation or heat energy and can be restored to the ground state, thereby weakening the direct effect of ultraviolet light on rubber and protecting the rubber. The aromatic amine structure and the benzophenone structure work together to give the antioxidant excellent anti-aging properties.

[0014] Since the antioxidant of the present invention has carbon-carbon double bonds, it can easily react chemically with the carbon-carbon double bonds on the side chains of the EPDM rubber and the carbon-carbon double bonds on the surface of the filler during the peroxide-induced vulcanization process. Therefore, the antioxidant, the EPDM rubber and the filler form a mutually cross-linked spatial network structure, which enables the antioxidant to stably exist in the rubber matrix and is not easily affected by the external environment and migrate out. Furthermore, the aromatic amine structure and the benzophenone structure in the antioxidant continuously play a synergistic role to protect the rubber material from high-temperature aging and ultraviolet aging.

[0015] A method for preparing weather-resistant rubber for a plastic runway comprises the following steps: The raw materials are weighed by weight and put into an internal mixer for mixing, then put into an extruder to extrude sheets, and then put into a flat vulcanizer for vulcanization. After the vulcanization, the sheets are allowed to stand at room temperature for 16 hours, and finally crushed, granulated and graded to obtain weather-resistant rubber for plastic tracks.

[0016] The beneficial effects of the present invention are as follows: the filler of the present invention is highly dispersed and stably exists in the rubber matrix under the action of the coupling agent; the antioxidant containing the aromatic amine structure and the benzophenone structure, the EPDM rubber and the filler are grafted and cross-linked through chemical action, thereby forming a stable spatial network structure. Therefore, the antioxidant of the present invention is also stably present in the rubber matrix, is not easily affected by the external environment and migrates, and fully exerts the effect of resisting thermal oxidative aging and ultraviolet aging, protects the rubber material and prolongs its service life. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1 The specific steps for preparing the antioxidant are as follows: S1. Under nitrogen protection, add 45.8 g of 2,4-dihydroxybenzophenone, 34 mL of triethylamine and 240 mL of chloroform into a 500 mL dry three-necked flask, stir and heat to 40°C until dissolved, then continue to heat to 80°C, then slowly add 23.1 mL of 3-chloro-2-chloromethyl propylene, keep warm for 3 hours after the addition is complete, distill under reduced pressure after the reaction is completed, purify by column chromatography (the eluent is selected from a mixed solvent of benzene and ethyl acetate, and the volume ratio of benzene to ethyl acetate is 8:2), and distill under reduced pressure to obtain intermediate 1; S2. Under nitrogen protection, add 19.5 mL of p-aminodiphenylamine, 17 mL of triethylamine and 120 mL of DMSO into a dry three-necked flask, stir to dissolve and then heat to 90°C, then slowly add a mixed solution of 30.3 g of intermediate 1 and 100 mL of DMSO, keep warm and react for 3 hours after the addition is completed, cool to room temperature after the reaction is completed, and distill under reduced pressure to obtain an antioxidant.

[0019] Example 2 The specific steps for preparing weather-resistant rubber for plastic runway are as follows: 70 parts of EPDM rubber, 10 parts of fumed silica, 10 parts of nano titanium dioxide, 5 parts of 15# white oil, 1 part of tert-butyl perbenzoate, 1 part of triallyl cyanurate, 1 part of vinyltrimethoxysilane and 0.6 parts of the antioxidant prepared in Example 1 were weighed by weight and put into an internal mixer for mixing, then put into an extruder to extrude a sheet, and then put into a flat vulcanizer for vulcanization. After the vulcanization is completed, it is allowed to stand at room temperature for 16 hours, and finally crushed, granulated and graded to obtain weather-resistant rubber for plastic runways.

[0020] Example 3 The specific steps for preparing weather-resistant rubber for plastic runway are as follows: 76 parts of EPDM rubber, 14 parts of nano titanium dioxide, 14 parts of carbon black, 7 parts of 32# white oil, 2 parts of 1,4-di-tert-butyl peroxyisopropylbenzene, 2 parts of triallyl isocyanurate, 2 parts of 3-(methacryloyloxy)propyltrimethoxysilane and 1 part of the antioxidant prepared in Example 1 were weighed by weight and put into an internal mixer for mixing, then put into an extruder to extrude a sheet, and then put into a flat vulcanizer for vulcanization. After the vulcanization is completed, it is allowed to stand at room temperature for 16 hours, and finally crushed, granulated and graded to obtain weather-resistant rubber for plastic runways.

[0021] Example 4 The specific steps for preparing weather-resistant rubber for plastic runway are as follows: 80 parts of EPDM rubber, 10 parts of nano titanium dioxide, 10 parts of talc, 10 parts of heavy calcium carbonate, 10 parts of 46# white oil, 1 part of di-tert-butyl peroxide, 1 part of 1,1-di-tert-butyl peroxide-3,3,5-trimethylcyclohexane, 1.5 parts of triallyl cyanurate, 1.5 parts of triallyl isocyanurate, 3 parts of vinyl triethoxysilane and 1.2 parts of the antioxidant prepared in Example 1 were weighed by weight and put into an internal mixer for mixing, then put into an extruder to extrude a sheet, and then put into a flat vulcanizer for vulcanization. After the vulcanization is completed, it is allowed to stand at room temperature for 16 hours, and finally crushed, granulated and graded to obtain a weather-resistant rubber for plastic track.

[0022] Comparative Example 1 The specific steps for preparing rubber for plastic track are as follows: The remaining steps remain unchanged, and only the coupling agent, vinyltrimethoxysilane, of Example 2 is removed, thereby preparing the rubber for the plastic track.

[0023] Comparative Example 2 The specific steps for preparing rubber for plastic track are as follows: The remaining steps remain unchanged, only the anti-aging agent in Example 2 is replaced by 0.3 parts of antioxidant 4010NA and 0.3 parts of ultraviolet absorber UV-531, thereby preparing rubber for plastic track.

[0024] Comparative Example 3 The specific steps for preparing rubber for plastic runway are as follows: The remaining steps remain unchanged, the coupling agent vinyltrimethoxysilane in Example 2 is removed, and the anti-aging agent is replaced by 0.3 parts of antioxidant 4010NA and 0.3 parts of ultraviolet absorber UV-531, thereby preparing rubber for plastic track.

[0025] Performance Testing The rubber for the plastic track prepared in Examples 2-4 and Comparative Examples 1-3 was made into samples according to the corresponding standards, and the following performance tests were performed: The tensile strength test was carried out in accordance with GB36246-2018; the rubber samples were heat aged at 110°C for 120h, UV aged at a vertical irradiation distance of 20cm, 30W UV lamp and room temperature for 120h, and the tensile strength was tested again to evaluate the weather resistance of the rubber; the acid and alkali resistance tests were carried out in accordance with GB / T19250 2013; the strength retention rate was tested by immersion in 120# solvent oil for 10 days to evaluate the solvent resistance of the rubber. The test results of all items are shown in the following table: In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0026] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A weather-resistant rubber for a plastic runway, characterized in that: The raw materials include the following parts by weight: 70-80 parts of EPDM rubber, 20-30 parts of filler, 5-10 parts of softener, 1-3 parts of vulcanizer, 1-3 parts of accelerator, 1-3 parts of coupling agent, and 0.6-1.2 parts of antioxidant; Wherein, the antioxidant is prepared by the following steps: S1. Add 2,4-dihydroxybenzophenone, triethylamine and chloroform into a flask under nitrogen protection, stir and heat to 40°C until dissolved, then heat to 80°C, add 3-chloro-2-chloromethylpropene, react for 3h, distill under reduced pressure, purify by column chromatography, and distill under reduced pressure to obtain intermediate 1; S2. Add p-aminodiphenylamine, triethylamine and DMSO into a flask under nitrogen protection, stir and heat to 90°C, add intermediate 1 and DMSO, react for 3 hours, cool, and distill under reduced pressure to obtain an antioxidant.

2. The weather-resistant rubber for plastic track according to claim 1, characterized in that: The usage ratio of 2,4-dihydroxybenzophenone, 3-chloro-2-chloromethylpropene, triethylamine and chloroform in step S1 is 45.8 g: 23.1 mL: 34 mL: 240 mL.

3. The weather-resistant rubber for plastic track according to claim 1, characterized in that: The usage ratio of p-aminodiphenylamine, intermediate 1, triethylamine and DMSO in step S2 is 19.5 mL:30.3 g:17 mL:220 mL.

4. The weather-resistant rubber for plastic track according to claim 1, characterized in that: The filler is one or more of fumed silicon dioxide, nano titanium dioxide, talcum powder, heavy calcium carbonate and carbon black.

5. The weather-resistant rubber for plastic track according to claim 1, characterized in that: The softener is one or more of white oils.

6. The weather-resistant rubber for plastic track according to claim 1, characterized in that: The vulcanizing agent is one or more of diisopropylbenzene peroxide, di-tert-butyl peroxide, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 1,4-di-tert-butylperoxyisopropylbenzene, and tert-butyl peroxybenzoate.

7. The weather-resistant rubber for plastic track according to claim 1, characterized in that: The accelerator is one or both of triallyl cyanurate and triallyl isocyanurate.

8. The weather-resistant rubber for plastic track according to claim 1, characterized in that: The coupling agent is one or more of vinyl trimethoxy silane, vinyl triethoxy silane and 3-(methacryloyloxy)propyl trimethoxy silane.

9. The method for preparing weather-resistant rubber for plastic track according to claim 1, characterized in that: The following steps are involved: The raw materials are weighed by weight and put into an internal mixer for mixing, then put into an extruder to extrude a sheet, and then put into a flat vulcanizer for vulcanization, allowed to stand at room temperature, and finally crushed, granulated, and graded to obtain weather-resistant rubber for plastic tracks.

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