A rubber composition for preventing discoloration and a tire made of the same

Abstract

The present application proposes a rubber composition for preventing discoloration and a tire made thereof, the rubber composition comprising, by mass, 100 parts of diene rubber, 25-150 parts of filler reinforcing agent, 1-50 parts of plasticizer, 0-15 parts of silane coupling agent, 2-8 parts of zinc oxide; 1-5 parts of stearic acid; 1.5-8 parts of chemical antioxidant, 1-8 parts of protective wax, 0.1-20 parts of castor oil, 0.1-15 parts of wax crystal modifier and 2-9 parts of vulcanizing agent and vulcanization accelerator. Compared with the prior art, the present application introduces castor oil and wax crystal modifier into the rubber composition, which can effectively prevent discoloration caused by amine antioxidant and protective wax without losing ozone aging resistance and maintaining the good appearance of the tire.

Description

Technical Field

[0001] The invention belongs to the field of tire rubber products, and particularly relates to a rubber composition for preventing discoloration and a tire made thereof. Background Art

[0002] The rubber composition for tire sidewalls, which is usually made of natural rubber or diene synthetic rubber, will deteriorate in the presence of heat, oxygen and / or ozone, causing cracks and damage to the surface. In order to prevent the generation and expansion of cracks in such rubber compositions caused by oxidation, amine antioxidants such as N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) are added as chemical antioxidants; in order to prevent static ozone aging, physical protective wax is added to form a protective film on the surface of the rubber product.

[0003] Although the above-mentioned amine antioxidants and protective waxes can effectively prevent the generation and expansion of cracks in the presence of heat, oxygen and / or ozone, these ingredients will migrate to the surface of rubber products, especially the surface of tires, and then discolor the rubber products during storage or use, thereby deteriorating the appearance of these rubber products. Among them, when the protective wax migrates to the surface of the rubber product, the surface will turn white; when the amine antioxidant migrates to the surface of the rubber product, the surface will turn brown. Since the tire is filled with carbon black, it should be black initially, but the sidewall turns reddish brown, resulting in serious color difference in appearance.

[0004] In view of these situations, some technical means are adopted in the prior art, such as adding bluing agent to rubber to neutralize the discoloration caused by antioxidant; or introducing polyoxyethylene alcohol nonionic surfactant into the rubber composition for tire sidewall to prevent discoloration caused by amine antioxidant and protective wax. However, according to these technologies, discoloration of the rubber composition for tire sidewall may not be fully prevented, or the ozone aging resistance of the rubber composition may be affected.

[0005] Therefore, it can be seen that how to make the rubber composition prevent discoloration caused by amine antioxidants and protective waxes without losing ozone aging resistance has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] In view of the technical problems existing in the prior art, the present application provides a rubber composition for preventing discoloration, so as to prevent discoloration caused by amine antioxidants and protective wax without losing the ozone aging resistance of the rubber composition. The rubber composition comprises, by mass, 100 parts of diene rubber, 25-150 parts of filler and reinforcing agent, 1-50 parts of plasticizer, 0-15 parts of silane coupling agent, 2-8 parts of zinc oxide, 1-5 parts of stearic acid, 1.5-8 parts of chemical antioxidant, 1-8 parts of protective wax, 0.1-20 parts of castor oil, 0.1-15 parts of wax crystal modifier, 2-9 parts of vulcanizing agent and vulcanization accelerator.

[0007] Preferably, the rubber composition comprises, by mass, 100 parts of diene rubber, 35-120 parts of filler and reinforcing agent, 5-45 parts of plasticizer, 0-12 parts of silane coupling agent, 2.5-6 parts of zinc oxide, 1.5-4 parts of stearic acid, 2-8 parts of chemical antioxidant, 1-6 parts of protective wax, 0.1-10 parts of castor oil, 0.1-8 parts of wax crystal modifier, and 2-7 parts of vulcanizer and vulcanization accelerator.

[0008] Preferably, the filler and reinforcing agent includes carbon black or white carbon black.

[0009] Preferably, the carbon black is one or a mixture of several of the N100, N200, N300, N500 and N600 series carbon blacks.

[0010] Preferably, the white carbon black is precipitated white carbon black, and the nitrogen adsorption specific surface area NSA of the precipitated white carbon black is 85 to 200 m 2 / g.

[0011] Preferably, the plasticizer is one or a mixture of environmentally friendly aromatic oil, environmentally friendly alkane oil, and environmentally friendly cycloalkane oil;

[0012] Preferably, the wax crystal modifier is maleic anhydride copolymer, polybetaine, polymethyl methacrylate or a mixture of the above.

[0013] Correspondingly, the present application also provides a pneumatic tire, which is prepared using the above-mentioned rubber composition.

[0014] The present application proposes a rubber composition for preventing discoloration and a tire made thereof, wherein the rubber composition comprises, by mass, 100 parts of diene rubber, 25-150 parts of a filler and reinforcing agent, 1-50 parts of a plasticizer, 0-15 parts of a silane coupling agent, 2-8 parts of zinc oxide, 1-5 parts of stearic acid, 1.5-8 parts of a chemical antioxidant, 1-8 parts of a protective wax, 0.1-20 parts of castor oil, 0.1-15 parts of a wax crystal modifier, and 2-9 parts of a vulcanizing agent and a vulcanization accelerator. Compared with the prior art, the present application introduces castor oil and a wax crystal modifier into the rubber composition, which can effectively prevent discoloration caused by amine antioxidants and protective waxes without losing ozone aging resistance and can maintain the good appearance of the tire. DETAILED DESCRIPTION

[0015] In view of the technical problems existing in the prior art, the present application provides a rubber composition for preventing discoloration, which comprises, by mass, 100 parts of diene rubber, 25-150 parts of a filler and reinforcing agent, 1-50 parts of a plasticizer, 0-15 parts of a silane coupling agent, 2-8 parts of zinc oxide, 1-5 parts of stearic acid, 1.5-8 parts of a chemical antioxidant, 1-8 parts of a protective wax, 0.1-20 parts of castor oil, 0.1-15 parts of a wax crystal modifier, and 2-9 parts of a vulcanizing agent and a vulcanization accelerator.

[0016] Among them, diene rubber includes natural rubber, butadiene rubber and other synthetic rubbers; natural rubber is a natural polymer compound with cis-1,4-polyisoprene as the main component, 91% to 94% of its components are rubber hydrocarbons (cis-1,4-polyisoprene), and the rest are non-rubber substances such as proteins, fatty acids, ash, and sugars; butadiene rubber is a synthetic rubber obtained by the polymerization of butadiene, also known as cis-1,4-butadiene rubber. Castor oil is a complex triglyceride, and the components of castor oil are: 80% to 85% ricinoleic acid, 7% oleic acid, 3% linoleic acid, 2% palmitic acid, and 1% stearic acid. It is flammable but not flammable, soluble in ethanol, slightly soluble in aliphatic hydrocarbons, almost insoluble in water, and slightly volatile.

[0017] The present application introduces castor oil and wax crystal modifier into the rubber composition, which can effectively prevent discoloration caused by amine antioxidants and protective wax without losing ozone aging resistance and can maintain the good appearance of the tire.

[0018] In order to ensure that the rubber composition has good performance, in a preferred embodiment of the present application, the rubber composition comprises, by mass, 100 parts of diene rubber, 35-120 parts of filler and reinforcing agent, 5-45 parts of plasticizer, 0-12 parts of silane coupling agent, 2.5-6 parts of zinc oxide, 1.5-4 parts of stearic acid, 2-8 parts of chemical antioxidant, 1-6 parts of protective wax, 0.1-10 parts of castor oil, 0.1-8 parts of wax crystal modifier, and 2-7 parts of vulcanizing agent and vulcanization accelerator.

[0019] In a preferred embodiment of the present application, the filler and reinforcing agent includes carbon black or white carbon black. The carbon black is preferably one or a mixture of N100, N200, N300, N500, and N600 series carbon black.

[0020] The white carbon black is preferably precipitated white carbon black, and the nitrogen adsorption specific surface area NSA of the precipitated white carbon black is 85 to 200 m 2 / g.

[0021] In a preferred embodiment of the present application, the plasticizer is one or a mixture of environmentally friendly aromatic oil, environmentally friendly alkane oil, and environmentally friendly cycloalkane oil.

[0022] In a preferred embodiment of the present application, the wax crystal modifier is one or a mixture of maleic anhydride copolymer, polybetaine, polymethyl methacrylate.

[0023] The rubber composition provided in the present application is cured using a sulfur curing system. The rubber composition is usually mixed by mixing the components in at least two stages, i.e., at least one non-productive mixing stage and one productive mixing stage. The filling material and the rubber are mixed in one or more non-productive mixing stages, and the mixing method can be completed by a method known to those skilled in the art of rubber mixing, which will not be described in detail here.

[0024] The following will combine specific implementation scenarios and use specific embodiments to further clearly and completely describe the technical solutions in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] Example 1

[0026] A rubber composition, which comprises, by mass, 50 parts of natural rubber, 50 parts of butadiene rubber, 55 parts of carbon black N330, 5 parts of environmentally friendly aromatic oil TDAE, 0.5 parts of castor oil, 3.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 2 parts of protective wax 3241H, 2 parts of stearic acid, 3 parts of zinc oxide, 0.6 parts of accelerator NS, and 1.6 parts of sulfur.

[0027] Example 2

[0028] A rubber composition, which comprises, by mass, 50 parts of natural rubber, 50 parts of butadiene rubber, 55 parts of carbon black N330, 5 parts of environmentally friendly aromatic oil TDAE, 2 parts of castor oil, 3.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 2 parts of protective wax 3241H, 2 parts of stearic acid, 3 parts of zinc oxide, 0.6 parts of accelerator NS, and 1.6 parts of sulfur.

[0029] Example 3

[0030] A rubber composition, which comprises, by mass, 50 parts of natural rubber, 50 parts of butadiene rubber, 55 parts of carbon black N330, 5 parts of environmentally friendly aromatic oil TDAE, 2 parts of castor oil, 3.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 3 parts of maleic anhydride copolymer, 2 parts of protective wax 3241H, 2 parts of stearic acid, 3 parts of zinc oxide, 0.6 parts of accelerator NS, and 1.6 parts of sulfur.

[0031] Example 4

[0032] A rubber composition, which comprises, by mass, 50 parts of natural rubber, 50 parts of butadiene rubber, 55 parts of carbon black N330, 5 parts of environmentally friendly aromatic oil TDAE, 2 parts of castor oil, 3.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 3 parts of polybetaine, 2 parts of protective wax 3241H, 2 parts of stearic acid, 3 parts of zinc oxide, 0.6 parts of accelerator NS, and 1.6 parts of sulfur.

[0033] Example 5

[0034] A rubber composition, which comprises, by mass, 50 parts of natural rubber, 50 parts of butadiene rubber, 55 parts of carbon black N330, 5 parts of environmentally friendly aromatic oil TDAE, 2 parts of castor oil, 3.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 3 parts of polymethyl methacrylate, 2 parts of protective wax 3241H, 2 parts of stearic acid, 3 parts of zinc oxide, 0.6 parts of accelerator NS, and 1.6 parts of sulfur.

[0035] Comparative Example 1

[0036] A rubber composition, which comprises, by mass, 50 parts of natural rubber, 50 parts of butadiene rubber, 55 parts of carbon black N330, 5 parts of environmentally friendly aromatic oil TDAE, 3.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 2 parts of protective wax 3241H, 2 parts of stearic acid, 3 parts of zinc oxide, 0.6 parts of accelerator NS, and 1.6 parts of sulfur.

[0037] Comparative Example 2

[0038] A rubber composition comprises, by mass, 50 parts of natural rubber, 50 parts of butadiene rubber, 55 parts of carbon black N330, 5 parts of environmentally friendly aromatic oil TDAE, 2 parts of stearic acid, 3 parts of zinc oxide, 0.6 parts of accelerator NS, and 1.6 parts of sulfur.

[0039] The rubber compositions of the above-mentioned Examples 1-5 and Comparative Examples 1-2 were kneaded. Specifically, the raw materials other than sulfur and vulcanization accelerator were mixed for 5 minutes using a 1.7-liter internal mixer, and then sulfur and vulcanization accelerator were added and mixed with the raw materials on an open mixer. The vulcanization conditions were 151°C × 30 minutes, and the vulcanization was performed on a flat vulcanizer to obtain a vulcanized rubber sheet with a thickness of 2 mm. The obtained vulcanized rubber sheet was used for the following experiments.

[0040] (Tensile test)

[0041] Following the GB528 test method, a dumbbell type 1 cutter was used to measure the tensile strength (MPa) and elongation at break EB (%).

[0042] (Ozone resistance test)

[0043] Following the ISO1431 test method, the test conditions are: 20% stretching, ozone concentration 50+5pphm, temperature 40°C, time 72 hours, and dynamic aging conditions. After exposure, the sample is taken out of the test tank, and the cracking state is observed and recorded based on Table 1.

[0044] Table 1

[0045]

[0046] (Color change experiment)

[0047] The discoloration degree of the samples after ozone aging was visually evaluated on a 5-point scale, with 5 points representing a black state (no change) and 1 point representing a brown state (large discoloration degree). The smaller the value, the more severe the discoloration.

[0048] The test results of various properties of the rubber compositions of Examples 1-5 and Comparative Examples 1-2 are shown in Table 2.

[0049] Table 2

[0050]

[0051] Comparative Example 1 is a conventional diene rubber composition using an antioxidant and a protective wax.

[0052] Comparative Example 2 is a diene rubber composition without using an antioxidant and a protective wax.

[0053] Example 1 adds castor oil on the basis of Comparative Example 1.

[0054] Example 2 increases the content of castor oil on the basis of Example 1.

[0055] Example 3 adds a wax crystal modifier-maleic anhydride copolymer based on Example 2.

[0056] Example 4 adds a wax crystal modifier, polybetaine, based on Example 2.

[0057] Example 5 adds a wax crystal modifier, polymethyl methacrylate, based on Example 2.

[0058] The results show that the use of castor oil and wax crystal modifier can effectively solve the problem of brown discoloration of the rubber composition and maintain the high physical properties and ozone aging resistance of the rubber composition. Therefore, the technical solution of the present invention can effectively prevent the discoloration caused by amine antioxidants and protective wax without losing ozone aging resistance and can maintain the good appearance of the tire.

[0059] The above disclosure is only a specific implementation scenario of the embodiment of the present invention, and is not intended to limit the present invention in other forms. Any method and material similar or equal to the recorded content can be applied to the method of the present invention. The preferred implementation methods and materials described in the text are only for demonstration purposes, and the embodiments of the present application are not limited thereto. Any technician familiar with the art may use the technical content disclosed above to change or modify it into an equivalent embodiment of equivalent changes. The above serial numbers are only for description and do not represent the advantages and disadvantages of the implementation scenarios. Unless otherwise defined, all professional and scientific terms used in the text have the same meanings as those familiar to those skilled in the art. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A rubber composition for preventing discoloration, characterized in that: The rubber composition comprises, by mass, 100 parts of diene rubber, 25-150 parts of a filler and reinforcing agent, 1-50 parts of a plasticizer, 0-15 parts of a silane coupling agent, 2-8 parts of zinc oxide, 1-5 parts of stearic acid, 1.5-8 parts of a chemical antioxidant, 1-8 parts of a protective wax, 0.1-20 parts of castor oil, 0.1-15 parts of a wax crystal modifier, and 2-9 parts of a vulcanizing agent and a vulcanization accelerator; The filler and reinforcing agent includes carbon black or white carbon black; The carbon black is one or a mixture of N100, N200, N300, N500, and N600 series carbon blacks; The wax crystal modifier is one or a mixture of maleic anhydride copolymer, polybetaine, polymethyl methacrylate.

2. The rubber composition according to claim 1, characterized in that The rubber composition comprises, in parts by mass: 100 parts of diene rubber, 35-120 parts of filler and reinforcing agent, 5-45 parts of plasticizer, 0-12 parts of silane coupling agent, 2.5-6 parts of zinc oxide, 1.5-4 parts of stearic acid, 2-8 parts of chemical antioxidant, 1-6 parts of protective wax, 0.1-10 parts of castor oil, 0.1-8 parts of wax crystal modifier, 2-7 parts of vulcanizing agent and vulcanization accelerator.

3. The rubber composition according to claim 1, characterized in that: The white carbon black is precipitated white carbon black, and the nitrogen adsorption specific surface area NSA of the precipitated white carbon black is 85 to 200 m 2 / g.

4. The rubber composition according to claim 1, characterized in that The plasticizer is one or a mixture of environmentally friendly aromatic oil, environmentally friendly alkane oil and environmentally friendly cycloalkane oil.

5. A pneumatic tire, characterized in that: The pneumatic tire is prepared using the rubber composition according to any one of claims 1 to 4.

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