Anti-tarnishing anti-aging agent as well as preparation method and application thereof

Abstract

The invention relates to an anti-tarnish anti-aging agent and a preparation method and application thereof, the anti-tarnish anti-aging agent has a structure as shown in the following formula (I): # imgabs0 #, the anti-aging agent provided by the invention has similar processability and equivalent processing safety compared with the existing anti-aging agent 4020, but has the outstanding characteristics of large molecular weight, more lasting aging resistance, good compatibility with rubber, difficult blooming and no surface tarnish after long-term use compared with the existing anti-aging agent 4020.

Description

Technical Field

[0001] The invention relates to an anti-discoloration antioxidant and a preparation method and application thereof, belonging to the technical field of antioxidants. Background Art

[0002] At present, p-phenylenediamine compounds are commonly used as antioxidants in rubber products, especially tires. This type of antioxidant is a highly efficient, multifunctional, low-toxic, and long-lasting antioxidant product. It is the most important and most widely used type of antioxidant. It can be used in rubber, plastics, motor oil, lubricating oil, heat transfer oil, diesel, gasoline, adhesives, etc. to prevent, stop, and slow down the degradation of materials due to heat and oxygen (such as O 2 , O 3 , etc.), flexure (for rubber, plastics, plastics), harmful metals (such as copper and manganese, etc.), and other factors that cause aging and degradation. Its main use is in the rubber industry. This type of antioxidant specifically includes dialkyl p-phenylenediamine, alkylaryl p-phenylenediamine and diaryl p-phenylenediamine. The most widely used antioxidant is 6PPD (N-(1,3-dimethylbutyl)-N′-phenyl p-phenylenediamine), and others include IPPD (N-isopropyl-N′-phenyl p-phenylenediamine), 77PD (N,N′-bis(1,4-dimethylpentyl) p-phenylenediamine), DTPD (a mixture of diphenyl p-phenylenediamine, di(tolyl) p-phenylenediamine and phenyltolyl p-phenylenediamine), etc.

[0003] The widely used rubber antioxidant 6PPD has a relatively small molecular weight. During the use of rubber products or tires, the antioxidant quickly migrates to the surface, causing pollution and discoloration on the tire surface. The antioxidant DTPD is a diaryl-p-phenylenediamine. As a recognized long-lasting and after-effect antioxidant, it has a relatively long-lasting anti-aging performance, but its compatibility with rubber is poor, and large amounts of use lead to frosting. In recent years, users have paid more and more attention to the durability of tire anti-aging and surface discoloration. Therefore, there is an urgent need for a new antioxidant that is more durable in anti-aging, does not discolor the surface after long-term use, and is resistant to discoloration. Summary of the invention

[0004] Aiming at the problems that the existing antioxidant 6PPD has a small molecular weight and is easy to change color, and the antioxidant DTPD has poor compatibility, is easy to bloom, and has poor anti-aging durability, the present invention provides an anti-discoloration antioxidant and a preparation method and application thereof.

[0005] The antioxidant of the invention has a large molecular weight, is more durable in anti-aging, has good compatibility with rubber, is not prone to blooming, and does not change color on the surface after long-term use.

[0006] The present invention is achieved through the following technical solutions:

[0007] An anti-discoloration and anti-aging agent having a structure shown in the following formula (I):

[0008]

[0009] Among them, R 1 , R 2 It is an alkyl chain derived from ketoamine condensation.

[0010] According to the preferred embodiment of the present invention, R 1 , R 2 The alkyl chain is derived from ketoamine condensation of one or more of acetone, 2-octanone, heptanone, methyl isobutyl ketone, cyclohexanone, and methyl isoamyl ketone.

[0011] The second object of the present invention is to provide a method for preparing the above-mentioned anti-discoloration and antioxidant.

[0012] A method for preparing an anti-discoloration and anti-aging agent comprises the following steps:

[0013] S1, 2,2-bis(4-aminophenyl)propane and p-chloronitrobenzene generate an antioxidant intermediate under the action of a catalyst;

[0014]

[0015] S2, adding the antioxidant intermediate, ketone and catalyst prepared in S1 into a reaction kettle, and reducing them in hydrogen to obtain a new antioxidant;

[0016]

[0017] Preferably according to the present invention, in step S1, the preparation of the antioxidant intermediate is carried out in an organic solvent.

[0018] According to the present invention, preferably, the organic solvent is toluene, xylene or dimethyl sulfoxide.

[0019] Most preferably, the organic solvent is xylene.

[0020] According to the preferred embodiment of the present invention, in step S1, the catalyst is a mixture of an inorganic salt catalyst and a metal catalyst, which can effectively shorten the reaction time.

[0021] Preferably according to the present invention, the inorganic salt catalyst is one of sodium carbonate, potassium carbonate and calcium carbonate, and the metal catalyst is one of copper oxide, skeleton copper and loaded copper.

[0022] Further preferably, in step S1, the catalyst is a mixture of sodium carbonate and copper oxide.

[0023] Preferably according to the present invention, in step S1, the amount of the inorganic salt catalyst in the catalyst is the same as the molar amount of p-chloronitrobenzene, and the amount of the metal catalyst is 1% of the mass of 2,2-bis(4-aminophenyl)propane.

[0024] Preferably, according to the present invention, in step S1, the molar ratio of 2,2-bis(4-aminophenyl)propane to p-chloronitrobenzene is 1.01-1.2:1, the reaction temperature is controlled so that the reaction liquid refluxes, and the reflux time is 10 min.

[0025] Most preferably, in step S1, the molar ratio of 2,2-bis(4-aminophenyl)propane to p-chloronitrobenzene is 1.01-1.05:1.

[0026] Preferably according to the present invention, in step S1, the mass volume ratio of 2,2-bis(4-aminophenyl)propane to the organic solvent is 1:5-10, unit: g / mL.

[0027] Preferably according to the present invention, in step S2, the ketone is one of acetone, 2-octanone, heptanone, methyl isobutyl ketone, cyclohexanone and methyl isoamyl ketone.

[0028] Preferably, according to the present invention, in step S2, the added ketone is both a raw material and a solvent, and the molar ratio of the antioxidant intermediate to the ketone is 1:4-8.

[0029] Preferably according to the present invention, in step S2, the molar ratio of the antioxidant intermediate to the ketone is 1:5.

[0030] Preferably according to the present invention, in step S2, the catalyst is one of skeleton nickel, skeleton copper, carbon-based palladium, carbon-based nickel, carbon-based copper, copper-zinc-aluminum-nickel catalyst, copper-zinc-aluminum-chromium catalyst, or a mixture of two or more thereof.

[0031] Preferably according to the present invention, in step S2, the catalyst is a carbon-based palladium catalyst.

[0032] Preferably according to the present invention, in step S2, the catalyst is a carbon-based palladium catalyst with a palladium loading of 3-5%, and the added amount of the catalyst is 2-6% of the mass of the antioxidant intermediate.

[0033] Most preferably, the catalyst is a carbon-based palladium catalyst with a palladium loading of 3%, and the amount of catalyst added is 2% of the weight of the antioxidant intermediate.

[0034] Preferably according to the present invention, in step S2, the reaction temperature is 80° C. and the hydrogen pressure is 1.5-2.0 MPa.

[0035] Preferably, according to the present invention, in step S2, after the reaction is completed, the catalyst is filtered out of the mother liquor, and the excess ketone and the generated alcohol are removed by reduced pressure distillation to obtain the product of the present invention.

[0036] The above anti-discoloration and anti-aging agent is used to prevent rubber materials from aging and discoloration.

[0037] The technical features and advantages of the present invention are as follows:

[0038] 1. Compared with diaryl-p-phenylenediamine and aryl-alkyl-p-phenylenediamine antioxidants, the antioxidant of the present invention has an ozone protection effect comparable to that of conventional aryl-alkyl-p-phenylenediamine antioxidants (such as antioxidant 4020) when applied to rubber tire products. While having an excellent ozone protection effect, the antioxidant can also significantly improve the tire side discoloration phenomenon caused by conventional p-phenylenediamine antioxidants, effectively solve the "frosting" phenomenon caused by the easy migration of organic antioxidants, and has a high application value in the anti-aging of rubber materials.

[0039] 2. The antioxidant of the present invention has similar processing performance and processing safety to the existing antioxidant 4020, but has the outstanding characteristics of having a larger molecular weight than the existing antioxidant 4020, more durable anti-aging, good compatibility with rubber, not easy to bloom, and no surface discoloration after long-term use.

[0040] 3. The antioxidant provided by the present invention has a simple preparation process, a high product yield and stable product quality, and is a promising antioxidant that can replace antioxidant 4020. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The following are the results of the dynamic ozone aging test for 72 hours for each rubber compound.

[0042] Figure 2 The following are the results of the static ozone aging test for 72 hours for each rubber compound. DETAILED DESCRIPTION

[0043] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, a novel antioxidant preparation method and application method thereof, a specific implementation method thereof and effects thereof are described in detail as follows.

[0044] Example 1

[0045] A method for preparing an anti-discoloration and anti-aging agent, comprising the following steps:

[0046] S1: Preparation of intermediates:

[0047] Add 600g of xylene solvent, 229g (1.01mol) of 2,2-bis(4-aminophenyl)propane, 157g (1mol) of p-chloronitrobenzene, 106g (1mol) of sodium carbonate, and 4.58g of copper oxide to a 2L three-necked flask, then stir and heat to reflux in an oil bath for about 10 minutes. If the residual amount of 2,2-bis(4-aminophenyl)propane detected by HPLC is less than 0.2%, the reaction is complete. Filter the reaction solution while hot, remove the solvent under reduced pressure, and obtain 450g of the intermediate, with a yield of 96.15% based on p-chloronitrobenzene;

[0048] S2: Synthesis of antioxidant:

[0049] Take 234g (0.5mol) of intermediate, 250g (2.5mol) of methyl isobutyl ketone, 4.68g of 3% carbon-based palladium catalyst, transfer to 2L reactor, convert gas, ensure safety, heat to 80°C, fill with hydrogen 1.5-2.0MPa and maintain, until the reaction no longer consumes hydrogen and the intermediate content is less than 0.2% (HPLC), the reaction is complete. Filter the hydrogenation mother liquor, remove the remaining ketone and the generated alcohol by vacuum distillation, and obtain 271g of anti-discoloration antioxidant, the yield of intermediate is 94.09%, the purity (HPLC) is 95.31%, and the molecular weight of anti-discoloration antioxidant is 576.

[0050] Example 2

[0051] A method for preparing an anti-discoloration and anti-aging agent, comprising the following steps:

[0052] S1: Preparation of intermediates:

[0053] Add 600g of solvent xylene, 229g (1.01mol) of 2,2-bis(4-aminophenyl)propane, 157g (1mol) of p-chloronitrobenzene, 106g (1mol) of sodium carbonate, and 4.58g of loaded copper into a 2L three-necked flask, then stir and heat to reflux in an oil bath for about 10 minutes. If the residual amount of 2,2-bis(4-aminophenyl)propane detected by HPLC is less than 0.2%, the reaction is complete. Filter the reaction solution while hot, remove the solvent under reduced pressure, and obtain 430g of the intermediate, with a yield of 91.88% based on p-chloronitrobenzene.

[0054] S2: Synthesis of antioxidant:

[0055] Take 234g (0.5mol) of intermediate, 232g (4mol) of acetone, 4.68g of 3% carbon-based palladium catalyst, transfer to a 2L reactor, convert the gas, ensure safety, heat to 80°C, fill with hydrogen 1.5-2.0MPa and maintain until the reaction no longer consumes hydrogen and the intermediate content is less than 0.2% (HPLC), the reaction is complete. Filter the hydrogenation mother liquor, remove the remaining ketone and the generated alcohol by vacuum distillation, and obtain 220.7g of anti-discoloration antioxidant, the yield of intermediate is 89.72%, and the purity (HPLC) is 94.83%. The molecular weight of the anti-discoloration antioxidant is 492.

[0056] Comparative Example 1

[0057] The method described in Example 1 is different in that:

[0058] In step S1, only sodium carbonate was added without copper oxide, and the remaining steps were exactly the same as those in Example 1, but no intermediate was obtained in the end.

[0059] Comparative Example 2

[0060] The method described in Example 1 is different in that:

[0061] In step S1, only copper oxide was added without sodium carbonate, and the remaining steps were exactly the same as those in Example 1, and no intermediate was obtained in the end.

[0062] Performance Verification

[0063] 1. Rubber compound formula and rubber compound preparation

[0064] Rubber formula (parts by weight): 45 parts of natural rubber NR, 55 parts of butadiene rubber BR, 45 parts of carbon black N330, 4.375 parts of zinc oxide ZnO-80, 2 parts of stearic acid SA, 1.8 parts of protective wax H3241, 1.875 parts of vulcanizing agent S-80, 1 part of accelerator NS-80, 3 parts of antioxidant in Example 1. At the same time, the antioxidant in Example 1 was replaced with antioxidant 4020 as a comparison, and the one without adding the antioxidant of the present invention was used as a blank control.

[0065] The preparation of the rubber compound is divided into a first-stage mixing process and a second-stage mixing process. The first-stage mixing process is as follows: weigh the raw materials according to the formula ratio, and mix 45 parts of natural rubber NR, 55 parts of butadiene rubber BR, 45 parts of carbon black N330, 4.375 parts of zinc oxide ZnO-80, 2 parts of stearic acid SA, and protective wax H3241. 1.8 parts of sulfoxide and 3 parts of antioxidant are added to the internal mixer, the rotor speed is 60-70 rpm, the pressure is 19-20MPa, the heating rate is 5-10℃ / 10 minutes, the temperature is raised to 100-120℃, the temperature is kept for 5-10 minutes, the temperature is further raised to 180℃, the rubber is discharged, and the first-stage mixed rubber is obtained; the second-stage mixing process is specifically as follows: the first-stage mixed rubber is added to the internal mixer, the vulcanizing agent S-80 and the accelerator NS-80 are added and mixed, and the pressure is 8-10MPa, the temperature is 70-80℃, the mixing is carried out for 1-2 minutes, and the speed is 10-15 rpm. After completion, the rubber compound can be obtained.

[0066] 2. Test methods for various performance parameters of rubber materials

[0067] Processing performance test: Using Mooney viscometer, scorch test was carried out according to the national standard GB / T 1233-92.

[0068] Vulcanization characteristics: The P3555 B2 disc vulcanizer produced by Beijing Huanfeng Rubber and Plastic Machinery Manufacturing Plant was used for testing according to GB / T98691997, with a test temperature of 160°C and a test time of 60 minutes.

[0069] Mechanical properties: The CMT 4104 electronic tensile testing machine produced by Shenzhen Xinsansi Material Testing Co., Ltd. was used to measure the tensile properties of the vulcanized rubber according to GB / T 528-2009. According to GB / T 77591996, a 29.0 mm × 12.5 mm cylindrical specimen was used to measure the compression permanent deformation at 100 ° C × 72 h, with a pre-compression rate of 25%.

[0070] Ozone resistance: The ozone resistance protection effect test result evaluation standard is based on GB / T 11206-2009 "Rubber Aging Test Surface Cracking Method" for ozone resistance test.

[0071] 3. Experimental results

[0072] 1. The processing characteristics of each rubber compound are shown in Table 1 below:

[0073] Table 1 Processing characteristics of rubber compounds

[0074] Rubber Name t5 / min Mn / Mv Blank control 30.86 63.87 4020 28.17 46.63 Example 1 28.48 47.47 Example 2 28.34 46.81

[0075] It can be seen from Table 1 that, compared with the blank control, the addition of the products of each embodiment of the present invention shortens the scorch time of the mixed rubber, reduces the Mooney viscosity, and improves the processing performance; compared with the antioxidant 4020 product, the products of each embodiment of the present invention have similar processing performance and processing safety to 4020.

[0076] 2. The vulcanization characteristics of the rubber are shown in Table 2 below:

[0077] Table 2 Vulcanization characteristics of rubber compounds

[0078] Rubber Name MH / dN-M ML / dN-M (MH-ML) / dN-M tc10 / s tc90 / s Blank control 6.02 0.72 5.30 338 834 4020 6.21 0.57 5.64 300 699 Example 1 6.56 0.68 5.98 289 678 Example 2 6.53 0.59 5.89 284 677

[0079] It can be seen from Table 2 that, compared with the blank sample, the addition of the products of each embodiment of the present invention improves the vulcanization rate and the degree of vulcanization crosslinking of the mixed rubber.

[0080] 3. The mechanical properties of the rubber are shown in Table 3 and Table 4:

[0081] Table 3 Mechanical properties before aging test

[0082]

[0083]

[0084] Table 4 Mechanical properties after aging test

[0085] Blank control 4020 Example 1 Example 2 Tensile strength / MPa 11.54 13.01 14.11 13.94 Tensile strength retention rate / % 60.28 61.19 68.53 66.95 M100 / MPa 4.55 5.21 5.30 5.25 M300 / MPa - 22.19 22.2 21.71 Elongation at break / % 138 210 227 228 Retention rate of elongation at break / % 22.37 33.98 36.67 36.95

[0086] It can be seen from Table 3 and Table 4 that before the aging experiment, compared with the blank control, after adding the antioxidant 4020 or the products of each embodiment of the present invention to the rubber material, the tensile strength and the tensile stress of the vulcanized rubber were improved. After the aging experiment, the products of each embodiment of the present invention still have good resistance to thermal oxidative aging, and the performance after thermal oxidative aging remains consistent with that before aging.

[0087] 4. The ozone resistance of the rubber compound is as follows: Figure 1 and Figure 2 As shown, Figure 1 This is a 72-hour dynamic ozone aging test result diagram of the blank control, antioxidant 4020, and the rubber obtained from the product of Example 1 of the present invention. Figure 2 This is the result of the static ozone aging test of the blank control, antioxidant 4020, and the rubber obtained from the product of Example 1 of the present invention for 72 hours. Figure 1 and Figure 2 It can be seen that the dynamic ozone performance of the rubber compound added with the product of the present invention is equivalent to that of the rubber compound added with 4020, but the addition of the product of the present invention makes the rubber compound have better anti-discoloration performance, is not easy to bloom, and does not change color on the surface after long-term use. In summary, the high molecular weight novel antioxidant provided by the present invention not only has excellent ozone protection effect, but also can effectively solve the problem that the organic antioxidant is easy to migrate out and discolor, and has a relatively excellent effect in anti-aging of rubber materials.

Claims

1. An anti-discoloration and anti-aging agent having a structure shown in the following formula (I): in, R1 and R2 are alkyl chains derived from condensation of ketoamine.

2. The anti-discoloration and antioxidant according to claim 1, characterized in that: R1 and R2 are alkyl chains derived from one or more of acetone, 2-octanone, heptanone, methyl isobutyl ketone, cyclohexanone and methyl isoamyl ketone by ketoamine condensation.

3. The method for preparing the anti-discoloration and antioxidant according to claim 1, comprising the following steps: S1, 2,2-bis(4-aminophenyl)propane and p-chloronitrobenzene generate an antioxidant intermediate under the action of a catalyst; S2, adding the antioxidant intermediate, ketone and catalyst prepared in S1 into a reaction kettle, and reducing them in hydrogen to obtain a new antioxidant; 4. The preparation method according to claim 3, characterized in that: In step S1, the preparation of the antioxidant intermediate is carried out in an organic solvent, the organic solvent is toluene, xylene, dimethyl sulfoxide, the catalyst is a mixture of an inorganic salt catalyst and a metal catalyst, the inorganic salt catalyst is one of sodium carbonate, potassium carbonate, and calcium carbonate, and the metal catalyst is one of copper oxide, skeleton copper, and loaded copper.

5. The preparation method according to claim 3, characterized in that: In step S1, the catalyst is a mixture of sodium carbonate and copper oxide, the amount of the inorganic salt catalyst in the catalyst is the same as the molar amount of p-chloronitrobenzene, the amount of the metal catalyst is 1% of the mass of 2,2-bis(4-aminophenyl)propane, the molar ratio of 2,2-bis(4-aminophenyl)propane to p-chloronitrobenzene is 1.01-1.2:1, the reaction temperature is controlled so that there is liquid reflux in the reaction, and the reflux time is 10 minutes.

6. The preparation method according to claim 3, characterized in that: In step S1, the mass volume ratio of 2,2-bis(4-aminophenyl)propane to the organic solvent is 1:5-10, unit: g / mL.

7. The preparation method according to claim 3, characterized in that: In step S2, the ketone is one of acetone, 2-octanone, heptanone, methyl isobutyl ketone, cyclohexanone, and methyl isoamyl ketone.

8. The preparation method according to claim 3, characterized in that: In step S2, the added ketone is both a raw material and a solvent, the molar ratio of the antioxidant intermediate to the ketone is 1:4-8, and the molar ratio of the antioxidant intermediate to the ketone is 1:

5.

9. The preparation method according to claim 3, characterized in that: In step S2, the catalyst is one of skeleton nickel, skeleton copper, carbon-based palladium, carbon-based nickel, carbon-based copper, copper-zinc-aluminum-nickel catalyst, copper-zinc-aluminum-chromium catalyst, or a mixture of two or more thereof; the catalyst is a carbon-based palladium catalyst; the catalyst is a carbon-based palladium catalyst with a palladium loading of 3-5%; the amount of the catalyst added is 2-6% of the mass of the antioxidant intermediate; the reaction temperature is 80° C.; the hydrogen pressure is 1.5-2.0 MPa; after the reaction is completed, the catalyst is filtered out of the mother liquor, and the excess ketone and the generated alcohol are removed by reduced pressure distillation to obtain the product of the present invention.

10. Use of the anti-discoloration and antioxidant according to claim 1 for anti-aging of rubber materials and preventing or slowing down discoloration.

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