A bio-based rubber oil and its preparation method

Abstract

The present invention provides a bio-based rubber oil with the following structural formula: #imgabs0# wherein, the structural formula of R1 is #imgabs1# and the structural formula of R2 is: #imgabs2# The present invention creatively uses tannic acid to prepare a bio-based rubber oil. The prepared bio-based rubber oil has a high CA content and a branched structure, realizing the environmental protection of rubber oil. When using the bio-based rubber oil of the present invention, the Mooney viscosity of the rubber compound is reduced, the wet friction force and tear strength are increased, and the rolling resistance is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of the rubber industry, and more particularly to a bio-based rubber oil and a preparation method thereof. Background Art

[0002] In the rubber processing system, rubber oil is used as a rubber softener to improve the processing performance of the rubber compound and reduce the production cost. It is an important processing aid in rubber processing and production. Since the compatibility between rubber oil and rubber is directly proportional to the CA value in the rubber oil, the higher the CA content, the better the compatibility between the rubber oil and the rubber. Therefore, aromatic oil and high-CA aromatic oil are generally selected as rubber processing oils. However, aromatic oil is a non-environmental protection oil product.

[0003] In 1994, the EU Chemicals Classification and Labelling Agency classified aromatic oils with a polycyclic aromatic hydrocarbon compound (PCA) mass fraction greater than 0.03 as carcinogenic and toxic substances. In 2019, the European Rubber Industry Association (BLIC) and the International Synthetic Rubber Producers Association jointly announced that non-toxic oil products will be used in tires, and toxic rubber oils will be completely prohibited in tire production as of January 1, 2019. Furthermore, the restrictive conditions were further clarified as the content of polycyclic aromatic hydrocarbon compounds (PCA) must be less than 3%, the content of benzo[a]pyrene must be less than 1 ppm, and the content of eight specific polycyclic aromatic hydrocarbons must be less than 10 ppm.

[0004] With the development of the rubber industry, the demand for aromatic rubber oils is increasing day by day. Therefore, in order to meet the needs of the industry and environmental protection regulations, the development of bio-based rubber oils with high CA content has great practical and economic significance. At present, there are patent reports on the development of environmental protection rubber oils. Patent CN104672563A discloses vegetable oils such as soybean oil, sunflower oil or cottonseed oil as rubber oils. However, simply using a single vegetable oil as a rubber oil results in a low CA content and poor compatibility with rubber. Patent CN113583709A discloses a preparation method of a high-aromatic and high-viscosity environmental protection rubber oil, which involves subjecting naphthenic vacuum residue to hydrofining and hydrodewaxing in sequence, and then obtaining a fraction with a boiling point ≥ 360 °C from the resulting hydrogenated liquid product through vacuum distillation as the high-aromatic and high-viscosity environmental protection rubber oil. However, the yield of the high-aromatic and high-viscosity environmental protection rubber oil prepared by this method is not high. Therefore, further improvement and development are still needed. Summary of the Invention

[0005] In view of the various deficiencies of the prior art, in order to solve the above problems, a bio-based rubber oil and a preparation method thereof are now proposed, and the following technical solutions are provided:

[0006] A bio-based rubber oil has the following structural formula:

[0007]

[0008] Wherein, R1 The structural formula is

[0009]

[0010] R 2 The structural formula is:

[0011]

[0012] In addition, the present invention also provides a method for preparing a bio-based rubber oil, comprising the following steps:

[0013] (1) Dissolve tannic acid in a solvent and add a catalyst;

[0014] (2) Raise the temperature and turn on the reflux condenser;

[0015] (3) Start dropping an alkanolamine material;

[0016] (4) After the dropping of the alkanolamine material is completed, react for 3 - 10 h, cool down, filter, and discharge.

[0017] Further, the solvent is at least one of water, methanol, and ethanol.

[0018] Further, the catalyst is hydrogen peroxide, potassium iodide, or sulfuric acid.

[0019] Further, raise the temperature to 30 - 100 °C.

[0020] Further, the alkanolamine material is at least one of methanolamine, ethanolamine, and propanolamine.

[0021] Further, the molar ratio of the amount of the alkanolamine material used to the amount of tannic acid used is 5 - 10:1.

[0022] Further, the amount of the catalyst used is 0.1 - 0.5% of the mass of tannic acid.

[0023] Due to the adoption of the above technical solutions, the beneficial technical effects of the present invention are:

[0024] 1. The present invention creatively prepares a bio-based rubber oil. The prepared bio-based rubber oil has a high CA content and a branched structure, realizing the environmental protection of the rubber oil;

[0025] 2. The bio-based rubber oil of the present invention improves the compatibility with raw rubber materials. Compared with traditional petroleum-based rubber oils, it can significantly reduce the Mooney viscosity of the rubber compound, improve the wet friction and tear strength, and reduce the rolling resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the infrared spectrum of the bio-based rubber oil of the present invention; Detailed implementation manners

[0027] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Based on the embodiments in this application, other similar embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0028] A bio-based rubber oil has the following structural formula:

[0029]

[0030] Wherein, R 1 The structural formula is

[0031]

[0032] R 2 The structural formula is:

[0033] The bio-based rubber oil of the present invention does not contain phenolic hydroxyl groups and has a branched structure, a highly branched three-dimensional "quasi-spherical" structure. After modification, an alkyl chain is introduced, which can better improve the compatibility with rubber materials. Compared with the linear structure of the same molecular weight, it lacks the entanglement between molecules and has a lower viscosity, which helps to reduce the Mooney viscosity of the rubber and improve the convenience of processing.

[0034] The new bio-based rubber oil has opened up a new direction for the preparation of rubber oil. Compared with traditional petroleum-based rubber oil, its preparation method is simple and convenient, with low cost, and can significantly reduce the Mooney viscosity of the rubber compound, improve the wet friction and tear strength, and reduce the rolling resistance.

[0035] Example 1

[0036] (1) Dissolve 100 parts of tannic acid in water and add potassium iodide at 0.3% of the mass of tannic acid;

[0037] (2) Raise the temperature to 50 °C and start reflux condensation;

[0038] (3) Start dropping methanolamine, and the molar amount of methanolamine is 10 times the molar amount of tannic acid;

[0039] (4) After the dropping of methanolamine is completed, react for 7 hours, cool down and filter, and discharge to obtain the bio-based rubber oil, and the yield of the bio-based rubber oil is 93.4%.

[0040] Example 2

[0041] (1) Dissolve 100 parts of tannic acid in water, and add hydrogen peroxide with a mass of 0.5% of the tannic acid;

[0042] (2) Raise the temperature to 100 °C and start reflux condensation;

[0043] (3) Start dropping ethanolamine, and the molar dosage of ethanolamine is 5 times that of tannic acid;

[0044] (4) After the dropping of ethanolamine is completed, react for 3 hours, cool down and filter, and discharge to obtain bio-based rubber oil, and the yield of bio-based rubber oil is 94.2%.

[0045] Example 3

[0046] (1) Dissolve 100 parts of tannic acid in water, and add sulfuric acid with a mass of 0.1% of the tannic acid;

[0047] (2) Raise the temperature to 30 °C and start reflux condensation;

[0048] (3) Start dropping propanolamine, and the molar dosage of propanolamine is 8 times that of tannic acid;

[0049] (4) After the dropping of propanolamine is completed, react for 10 hours, cool down and filter, and discharge to obtain bio-based rubber oil, and the yield of bio-based rubber oil is 93.1%.

[0050] Example 4

[0051] (1) Dissolve 100 parts of tannic acid in water, and add hydrogen peroxide with a mass of 0.3% of the tannic acid;

[0052] (2) Raise the temperature to 70 °C and start reflux condensation;

[0053] (3) Start dropping propanolamine, and the molar dosage of propanolamine is 5 times that of tannic acid;

[0054] (4) After the dropping of propanolamine is completed, react for 6 hours, cool down and filter, and discharge to obtain bio-based rubber oil, and the yield of bio-based rubber oil is 94.5%.

[0055] Example 5

[0056] (1) Dissolve 100 parts of tannic acid in water, and add potassium iodide with a mass of 0.1% of the tannic acid;

[0057] (2) Raise the temperature to 65 °C and start reflux condensation;

[0058] (3) Start dropping methanolamine, and the molar dosage of propanolamine is 6 times that of tannic acid;

[0059] (4) After the addition of propanolamine was completed, the reaction was carried out for 5 hours, then the temperature was lowered and filtered, and the product was discharged to obtain bio-based rubber oil, and the yield of bio-based rubber oil was 94.7%.

[0060] Comparative Example 1

[0061] (1) Dissolve 100 parts of tannic acid in water and add potassium iodide at 0.05% of the mass of tannic acid.

[0062] (2) Raise the temperature to 120 °C and turn on the reflux condenser.

[0063] (3) Start to dropwise add methanolamine, and the molar amount of propanolamine used is 12 times the molar amount of tannic acid.

[0064] (4) After the addition of methanolamine was completed, the reaction was carried out for 2 hours, then the temperature was lowered and filtered, and the product was discharged to obtain bio-based rubber oil, and the yield of bio-based rubber oil was 89.3%.

[0065] Comparative Example 2

[0066] In Comparative Example 2, A1820 aromatic rubber oil was prepared by the existing technology as the rubber oil.

[0067] Comparative Example 3

[0068] The difference between the substance in Comparative Example 3 and the bio-based rubber oil in Example 1 lies in R 2 is different. In Comparative Example 3, R 2 is the H group.

[0069] The corresponding property tests were carried out on the bio-based rubber oils obtained in Examples 1-5 and Comparative Examples 1-3, and the test results are shown in Table 1 below.

[0070] Table 1 Property test results of the rubber oils obtained in Examples 1-5 and Comparative Examples 1-3

[0071]

[0072]

[0073] According to the regulations of AfPS (German Product Safety Commission) and the European Union on polycyclic aromatic hydrocarbons, the content of polycyclic aromatic hydrocarbons was determined in accordance with SN / T1877.3-2007 "Determination Method of Polycyclic Aromatic Hydrocarbons in Mineral Oils". The content of BaP (benzo[a]pyrene) should be less than 1 ppm. The sum of the 8 items should be less than 10 ppm. The 8 items refer to the sum of the contents of benzo[a]anthracene + chrysene + benzo[b]fluoranthene + benzo[k]fluoranthene + benzo[j]fluoranthene + benzo[e]pyrene + benzo[a]pyrene + dibenzo[a,h]anthracene.

[0074] The rubber oils obtained in Examples 1-5 and Comparative Examples 1-3 were added to the rubber compound processing to obtain different rubber compounds, and the mechanical properties, Mooney viscosity, wet skid resistance and rolling resistance of the obtained rubber compounds were tested.

[0075] The tensile strength was tested according to GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The elongation at break was tested according to GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0076] Table 2 Test results of mechanical properties of rubber compounds obtained with the rubber oils of Examples 1-5 and Comparative Examples 1-3

[0077]

[0078]

[0079] As can be seen from Table 2 above, the Mooney viscosity of the rubber compound using the bio-based rubber oil of the present application was reduced, indicating that the bio-based rubber oil can improve the processing performance of the rubber compound. In addition, the mechanical properties of the rubber compound with the bio-based rubber oil of the present application were also correspondingly improved. When the elongation rate was 200%, the mechanical strength could reach 2.9 MPa.

[0080] The environmentally friendly rubber oil obtained in Example 1 was subjected to infrared testing, as Figure 1 shown, obvious characteristic peaks appeared in the curve at 1700-1800 cm -1 indicating that the hydroxyl group and the amino group reacted successfully, and the hydrogen atom in the phenolic hydroxyl group was replaced by the amino group, forming a new characteristic peak.

[0081] In addition, it should be understood that although this specification is described according to the embodiments, not each embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A bio-based rubber oil, characterized in that: Its structural formula is as follows: Among them, the structural formula of R1 is: The structural formula of R2 is: ； R2 is at least one of -NH-CH2-OH, -NH-CH2- CH2-OH, and -NH-CH2- CH2- CH2-OH.

2. The method for preparing a bio-based rubber oil according to claim 1, characterized in that: The following steps are involved: (1) dissolving tannic acid in a solvent and adding a catalyst; (2) Raise the temperature and start reflux condensation; (3) Start adding alcoholamine materials; (4) After the addition of the amine material is completed, react for 3-10 hours, cool down, filter, and discharge.

3. The method for preparing a bio-based rubber oil according to claim 2, characterized in that: The solvent is at least one of water, methanol and ethanol.

4. The method for preparing a bio-based rubber oil according to claim 2, characterized in that: The catalyst is hydrogen peroxide, potassium iodide or sulfuric acid.

5. The method for preparing a bio-based rubber oil according to claim 2, characterized in that: Raise the temperature to 30-100°C.

6. The method for preparing a bio-based rubber oil according to claim 2, characterized in that: The alcoholamine material is at least one of methanolamine, ethanolamine and propanolamine.

7. The method for preparing a bio-based rubber oil according to claim 2, characterized in that: The molar ratio of the alcoholamine material to the tannic acid is 5-10:

1.

8. The method for preparing a bio-based rubber oil according to claim 2, characterized in that: The amount of the catalyst used is 0.1-0.5% of the mass of tannic acid.

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