Method for preparing lubricating grease and application thereof

Abstract

The present invention relates to the field of lubricating grease, and discloses a method for preparing lubricating grease and its application. The method comprises: mixing alkylbenzene sulfonic acid, a calcium-containing alkaline substance, a calcium carboxylate and a part of a base oil, gradually adding water to the obtained mixture to react the alkylbenzene sulfonic acid with the calcium-containing alkaline substance to generate calcium alkylbenzene sulfonate, heating and dehydrating, and then mixing the product with the remaining base oil and an optional additive; wherein the calcium carboxylate is selected from at least one of an aliphatic calcium carboxylate and an aromatic calcium carboxylate. The method for preparing lubricating grease of the present invention has a simple process, a short time required, and no volatile gas is generated during the reaction, which is beneficial to environmental protection.

Description

Technical Field

[0001] The present invention relates to the field of lubricating grease, and in particular to a method for preparing lubricating grease and application thereof. Background Art

[0002] As mechanical equipment has increasingly higher requirements for lubrication conditions, the grease used is required to have a higher dropping point to meet the requirements for use under high temperature conditions.

[0003] Some documents have introduced the composition and preparation method of composite calcium sulfonate-based grease. For example, CN1414076A discloses a preparation method of composite calcium sulfonate-based grease, which requires converting high-alkalinity petroleum calcium sulfonate before further preparing the grease. The process is complicated and the quality is difficult to control. CN102604724A discloses the composition of a composite calcium-based grease thickener, including calcium benzoate, calcium salicylate, calcium borate, as well as calcium acetate, calcium octoate and calcium 12-hydroxystearate. In order to improve the performance of the grease, additives such as graphite and tungsten disulfide are also added. The heat resistance of the above-mentioned grease compositions is not good, and they will turn black and harden after long-term use under high temperature conditions. When two organic acids are used to react with calcium hydroxide to prepare composite calcium-based grease, the organic acid and calcium eventually form a calcium complex with a relatively complex structure (CN103958653A). The reaction process is relatively complicated, the reaction time is long, and the organic acid may produce odor during the reaction, which is not conducive to environmental protection. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems of the prior art in that the process is complex, time-consuming and environmentally unfriendly, and to provide a method for preparing grease and its application.

[0005] To achieve the above-mentioned object, the present invention provides a method for preparing lubricating grease, comprising: mixing alkylbenzene sulfonic acid, a calcium-containing alkaline substance, a calcium carboxylate, and a portion of a base oil; gradually adding water to the resulting mixture to react the alkylbenzene sulfonic acid with the calcium-containing alkaline substance to form calcium alkylbenzene sulfonate; heating the mixture for dehydration; and then mixing the product with the remainder of the base oil and optional additives; wherein the calcium carboxylate is selected from at least one of an aliphatic calcium carboxylate and an aromatic calcium carboxylate.

[0006] The present invention also provides the use of the above method in improving the water resistance of grease.

[0007] The method for preparing lubricating grease of the present invention is simple and time-saving. It also generates minimal volatile gases and foam during the reaction, thus contributing to environmental protection. Furthermore, the method can produce lubricating grease with excellent water resistance, low cone penetration, high dropping point, and strong extreme pressure and wear resistance without the introduction of additional additives. DETAILED DESCRIPTION

[0008] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0009] The present invention provides a method for preparing lubricating grease, characterized in that the method comprises: mixing alkylbenzene sulfonic acid, a calcium-containing alkaline substance, a calcium carboxylate and a portion of base oil, gradually adding water to the resulting mixture to react the alkylbenzene sulfonic acid and the calcium-containing alkaline substance to form calcium alkylbenzene sulfonate, heating and dehydrating the mixture, and then mixing the product with the remaining base oil and optional additives; wherein the calcium carboxylate is selected from at least one of aliphatic calcium carboxylate and aromatic calcium carboxylate.

[0010] According to the present invention, the amount of the calcium-containing alkaline substance used can be 60-160 g, preferably 80-140 g, per kilogram of alkylbenzenesulfonic acid.

[0011] According to the present invention, the amount of calcium carboxylate used may be 0.5-2.5 kg, preferably 0.6-1.5 kg, per kilogram of alkylbenzenesulfonic acid.

[0012] According to the present invention, the total amount of base oil used may be 0.5-6 kg, preferably 1.5-3.5 kg, per kilogram of alkylbenzenesulfonic acid.

[0013] According to the present invention, the addition rate of water is preferably 0.1-20 L / min (e.g., 0.3, 0.4, 0.5, 0.9, 1, 1.2, 1.3, 1.4, 2.5, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18 L / min or any value therebetween) per kilogram of alkylbenzene sulfonic acid.

[0014] According to the present invention, water is introduced into the system in a gradual manner. The reaction between the alkylbenzene sulfonic acid and the calcium-containing alkaline substance usually occurs at a certain temperature, so the system needs to be heated, and water can be added to the system during the heating process. According to a preferred embodiment of the present invention, the method comprises: mixing the alkylbenzene sulfonic acid, the calcium-containing alkaline substance, the calcium carboxylate of the alkylbenzene sulfonic acid calcium salt, and a portion of the base oil; heating the mixture to 100-120°C and maintaining the temperature for 5-10 minutes; gradually adding water to the resulting mixture during the heating process to allow the alkylbenzene sulfonic acid to react with the calcium-containing alkaline substance to form calcium alkylbenzene sulfonate; then heating the mixture to 150-170°C for dehydration; and then mixing the product with the remaining base oil and optional additives. The method may also include: cooling the material after mixing with the remaining base oil, and when the temperature drops to 80-100°C, performing a grinding process to make the material more evenly dispersed. It will be understood by those skilled in the art that if the water is not added completely during the heating process, it is continued to be added during the insulation process. However, the method of the present invention can generally effectively shorten the reaction time and avoid the generation of foam in the system.

[0015] According to the present invention, the total amount of water added is preferably 0.2-1.5 kg (e.g., 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.7, 1, 1.4 kg or any value therebetween) per kilogram of alkylbenzene sulfonic acid. The method of the present invention can significantly reduce the relative amount of water used.

[0016] According to the present invention, the base value of the alkylbenzenesulfonic acid is 100-180 mgKOH / g.

[0017] According to the present invention, the alkylbenzene sulfonic acid can be any common alkylbenzene sulfonic acid in the art, and its structural formula can be: R1-C6H4-SO3H, wherein R1 is preferably a C10-C24 alkyl group (straight chain or branched). The alkylbenzene sulfonic acid can be a single component with a specific structural formula, such as dodecylbenzene sulfonic acid, or a mixture of multiple alkylbenzene sulfonic acids with different carbon numbers, such as medium alkylbenzene sulfonic acid and heavy alkylbenzene sulfonic acid, as long as each component in the mixture satisfies the above general formula.

[0018] According to a preferred embodiment of the present invention, the alkylbenzenesulfonic acid is at least one selected from dodecylbenzenesulfonic acid, octadecylbenzenesulfonic acid and tetracosylbenzenesulfonic acid.

[0019] According to the present invention, the calcium carboxylate can be a calcium carboxylate salt commonly found in the art, such as a calcium carboxylate having 2 to 10 carbon atoms. The calcium carboxylate can have a structural formula of (R2-COO)2Ca and / or (OOC-R3-COO)Ca, wherein R2 is preferably a substituted or unsubstituted phenyl group, or a substituted or unsubstituted C1-C8 hydrocarbon group, and R3 is a C1-C10 alkylene group. More preferably, the substituted group in the calcium carboxylate is a hydroxyl group.

[0020] According to a more preferred embodiment of the present invention, the calcium carboxylate is selected from at least one of calcium acetate, calcium propionate, calcium butyrate, calcium lactate, calcium sorbate, calcium salicylate, calcium sebacate and calcium benzoate.

[0021] According to the present invention, there are no special requirements for the calcium-containing alkaline substance, as long as it can react with alkylbenzenesulfonic acid to form calcium alkylbenzenesulfonate. Preferably, the calcium-containing alkaline substance is selected from at least one of calcium hydroxide, calcium carbonate, calcium bicarbonate, calcium phosphate, calcium monohydrogen phosphate and calcium dihydrogen phosphate.

[0022] According to the present invention, the weight ratio of the part of the base oil to the balance of the base oil is 0.5-5, preferably 1-4.

[0023] According to the present invention, the base oil can be any base oil used in lubricating greases, such as mineral oil, synthetic oil (silicone oil, olefin oil and / or ester oil), vegetable oil or a mixture thereof. Preferably, the base oil has a kinematic viscosity of 2-300 mm at 100°C. 2 / s, preferably 6-100mm 2 In the present invention, "kinematic viscosity" is measured with reference to GB / T265-1988.

[0024] According to the present invention, the additives may include various components that can be used to improve the performance of the grease, such as extreme pressure anti-wear agents, antioxidants, corrosion inhibitors, rust inhibitors, detergents, dispersants, and tackifiers. According to a preferred embodiment of the present invention, the additives may be extreme pressure anti-wear agents to further enhance the extreme pressure and anti-wear properties of the grease composition. The extreme pressure anti-wear agent may be at least one selected from calcium carbonate, calcium bicarbonate, calcium phosphate, calcium monohydrogen phosphate, and calcium dihydrogen phosphate, preferably calcium carbonate. The calcium carbonate may be of conventional crystal type, such as aragonite, calcite, or vaterite. Other additives besides the extreme pressure anti-wear agent may be conventional in the art and will not be described in detail herein. Although the grease composition of the present invention may contain other additives, the present invention can still produce a grease with a low cone penetration, a high dropping point, and strong extreme pressure and anti-wear properties without the introduction of other additives. The additional introduction of other additives will further improve the performance of the grease.

[0025] According to a particularly preferred embodiment of the present invention, a method for preparing a grease composition of the present invention comprises: adding mineral oil and dodecylbenzenesulfonic acid (base value 170-175 mg KOH / g) to a reactor, stirring uniformly, adding calcium hydroxide and calcium benzoate, stirring uniformly, gradually adding water while heating to 100-110°C, holding the temperature for 4-6 minutes, continuing to heat to 140-160°C, holding the temperature for 4-6 minutes, stopping heating, adding mineral oil, cooling the material to 90-110°C, and grinding to obtain a grease composition, wherein, per kilogram of dodecylbenzenesulfonic acid, the amount of calcium hydroxide is 130-140g, the amount of calcium benzoate is 0.8-1.2kg, the total amount of mineral oil is 1.5-2kg, the water is added at a rate of 0.9-1 L / min, and the total amount of water added is 0.4-0.6kg. According to this preferred embodiment, a grease with better performance can be obtained, as shown in the following examples.

[0026] The present invention also provides the use of the above-described method for improving the water resistance of lubricating grease. Specifically, the present invention relates to a method for improving the water resistance of lubricating grease, characterized in that the method comprises: mixing alkylbenzene sulfonic acid, a calcium-containing alkaline substance, a calcium carboxylate, and a portion of base oil; gradually adding water to the resulting mixture to react the alkylbenzene sulfonic acid and the calcium-containing alkaline substance to form calcium alkylbenzene sulfonate; heating the mixture for dehydration; and then mixing the product with the remainder of the base oil and optional additives; wherein the calcium carboxylate is selected from at least one of an aliphatic calcium carboxylate and an aromatic calcium carboxylate. The specific selection, dosage, and conditions of the various raw materials are as previously described and will not be elaborated upon here.

[0027] The present invention will be described in detail below by way of examples.

[0028] The test reference for cone penetration (25°C, 0.1mm, 60 times): GB / T 269-1991. The smaller the 60-time working cone penetration, the stronger the thickening ability.

[0029] Dropping point test reference: GB / T 3498-2008, the higher the dropping point, the better the high temperature performance;

[0030] Extreme pressure performance (maximum no-seizure load, P B The detection reference of extreme pressure performance (sintering load, P) is SH / T 0202-1992 "Determination of extreme pressure performance of lubricating grease (four-ball machine method)", and the setting conditions of the four-ball test machine are speed 1770r / min, time 10s; extreme pressure performance (sintering load, P DThe test reference for the d-value is SH / T 0202-1992 "Determination of the extreme pressure properties of lubricating greases (four-ball tester method)". The four-ball tester is set at a speed of 1770 r / min and a test time of 10 s. The test reference for the anti-wear property (d-value) is SH / T 0204-1992 "Determination of the anti-wear properties of lubricating greases (four-ball tester method)". The four-ball tester is set at a speed of 1200 r / min, a load of 392 N, and a test time of 60 min. The larger the PB and PD values ​​and the smaller the d value, the stronger the extreme pressure and anti-wear properties.

[0031] Grease water resistance is tested according to SH / T 0643-1997, "Determination of water spray resistance of lubricating greases." The specific method involves evenly applying the grease to a stainless steel plate and spraying it with water at the specified test temperature (38°C ± 0.5°C) and pressure (276kPa ± 7kPa). After 5 minutes, the percentage weight loss of the grease is measured as a measure of the grease's water spray resistance. A smaller value indicates better water resistance.

[0032] Grease odor testing follows the standard GB / T 5525-2008, "Identification of Transparency, Odor, and Flavor of Vegetable Oils and Fats." The procedure is as follows: During the grease production process, a small amount of grease sample is heated to 50°C in a beaker and removed from the heat source. The tester then smells the grease while stirring. Odor levels are classified as follows: Level 1 (odorless or nearly odorless), Level 2 (slightly pungent), and Level 3 (pungent).

[0033] Mineral oil (100℃ kinematic viscosity is 30mm 2 / s) was purchased from Beijing Yanshan Petrochemical; olefin oil (100℃ kinematic viscosity 6mm 2 / s) purchased from Exxon Mobil; phenylmethyl silicone oil (100℃ kinematic viscosity of 20mm 2 / s) were purchased from Sichuan Chenguang Chemical;

[0034] Alkylbenzene sulfonic acid was purchased from Nanjing Alkylbenzene Factory; organic acid calcium salts such as calcium benzoate, calcium acetate, and calcium citrate were purchased from Beijing Reagent Company.

[0035] Example 1

[0036] In a reaction kettle, 360g of mineral oil and 270g of dodecylbenzenesulfonic acid (base value 173mg KOH / g) were added and stirred evenly. 36.7g of calcium hydroxide and 270g of calcium benzoate were added and stirred evenly. 135g of water was gradually added at a rate of 0.25L / min while heating to 100°C and holding the temperature for 5 minutes. Heating was continued to increase the temperature to 150°C and hold the temperature for 5 minutes. Heating was stopped, 100g of mineral oil was added, the material was cooled to 100°C, and ground using a three-wheel mill to produce a grease sample. The production of volatile gases was minimal and no foaming was generated during the preparation process.

[0037] Example 2

[0038] The material composition and process conditions were the same as those in Example 1, except that the base oil was replaced with olefin oil. During the preparation process, the amount of volatile gas generated was small and no foam was generated.

[0039] Example 3

[0040] The material composition and process conditions were the same as those in Example 1, except that the base oil was replaced with phenylmethyl silicone oil. During the preparation process, the amount of volatile gas generated was small and no foam was generated.

[0041] Example 4

[0042] In a reaction kettle, 400g of mineral oil and 150g of dodecylbenzenesulfonic acid (base value 173mg KOH / g) were added and stirred evenly. 20.4g of calcium hydroxide and 150g of calcium benzoate were added and stirred evenly. 75g of water was gradually added at a rate of 0.2L / min while heating to 120°C and holding the temperature for 5 minutes. Heating was continued to increase the temperature to 170°C and hold the temperature for 5 minutes. Heating was stopped, 100g of mineral oil was added, and the mixture was cooled to 100°C. Grease samples were prepared using a three-wheel mill. The production of volatile gases was minimal and no foaming was generated during the preparation process.

[0043] Example 5

[0044] In a reaction kettle, 300 g of mineral oil and 300 g of octadecylbenzenesulfonic acid (base value 121 mg KOH / g) were added and stirred evenly. 28.4 g of calcium hydroxide and 200 g of calcium benzoate were added and stirred evenly. 100 g of water was gradually added at a rate of 0.1 L / min while heating to 110°C and holding the temperature for 5 minutes. Heating was continued to increase the temperature to 160°C and hold the temperature for 5 minutes. Heating was stopped, 200 g of mineral oil was added, and the mixture was cooled to 100°C. Grease samples were prepared using a three-wheel mill. The production of volatile gases was minimal and no foaming was generated during the preparation process.

[0045] Example 6

[0046] In a reaction kettle, 300 g of mineral oil and 200 g of tetracosylbenzenesulfonic acid (base value 107 mg KOH / g) were added and stirred evenly. 17 g of calcium hydroxide and 300 g of calcium benzoate were added and stirred evenly. 150 g of water was gradually added at a rate of 0.7 L / min while heating to 100°C and holding the temperature for 5 minutes. Heating was continued to increase the temperature to 150°C and hold the temperature for 5 minutes. Heating was stopped, 200 g of mineral oil was added, the material was cooled to 100°C, and ground using a three-wheel mill to produce a grease sample. The production of volatile gases was minimal and no foaming was generated during the preparation process.

[0047] Example 7

[0048] In a reaction kettle, 360g of mineral oil and 270g of dodecylbenzenesulfonic acid (base value 173mg KOH / g) were added and stirred evenly. 36.7g of calcium hydroxide and 270g of calcium acetate were added and stirred evenly. 135g of water was gradually added at a rate of 0.3L / min while heating to 100°C and holding the temperature for 5 minutes. Heating was continued to increase the temperature to 150°C and hold the temperature for 5 minutes. Heating was stopped, 100g of mineral oil was added, the material was cooled to 100°C, and ground using a three-wheel mill to produce a grease sample. The preparation process produced little volatile gas and no foam.

[0049] Example 8

[0050] In a reaction kettle, 360g of mineral oil and 270g of dodecylbenzenesulfonic acid (base value 173mg KOH / g) were added and stirred evenly. 36.7g of calcium hydroxide and 270g of calcium citrate were added and stirred evenly. 135g of water was gradually added at a rate of 0.8L / min while heating to 100°C and holding the temperature for 5 minutes. Heating was continued to increase the temperature to 150°C and hold the temperature for 5 minutes. Heating was stopped, 100g of mineral oil was added, the material was cooled to 100°C, and ground using a three-wheel mill to produce a grease sample. The preparation process produced little volatile gas and no foam.

[0051] Example 9

[0052] In a reaction kettle, 360g of mineral oil and 270g of dodecylbenzenesulfonic acid (base value 173mg KOH / g) were added and stirred evenly. 36.7g of calcium hydroxide and 270g of calcium benzoate were added and stirred evenly. 135g of water was gradually added at a rate of 1.5L / min while heating to 100°C and holding the temperature for 5 minutes. Heating was continued to increase the temperature to 150°C and hold the temperature for 5 minutes. Heating was stopped, 100g of mineral oil was added, the material was cooled to 100°C, and ground using a three-wheel mill to produce a grease sample. The preparation process produced little volatile gas and no foam.

[0053] Test Example 1

[0054] The performance tests were performed on the grease samples prepared in the examples and comparative examples. The test results are shown in Table 1.

[0055] Table 1

[0056]

[0057] As can be seen from Table 1, the present invention can produce a grease with excellent water resistance, low cone penetration, high dropping point, and strong extreme pressure and wear resistance without the addition of any additional additives. Further experiments have shown that the grease obtained by the present invention exhibits superior water resistance and other properties compared to grease samples prepared by directly mixing alkylbenzenesulfonic acid, aliphatic carboxylic acid, or aromatic carboxylic acid with a calcium-containing alkaline substance.

[0058] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing grease, characterized in that: The method comprises: mixing alkylbenzene sulfonic acid, calcium-containing alkaline substances, calcium carboxylate and part of base oil, gradually adding water and heating to 100-120° C., keeping the temperature constant for 5-10 minutes, so that the alkylbenzene sulfonic acid and the calcium-containing alkaline substances react to generate calcium alkylbenzene sulfonate, continuing to heat to 150-170° C. for dehydration, and then mixing the product with the remaining base oil and optional additives; wherein the calcium carboxylate is selected from at least one of aliphatic calcium carboxylate and aromatic calcium carboxylate; The speed of adding water is 0.1-20 L / min for each kilogram of alkylbenzene sulfonic acid, and the total amount of water added is 0.2-1.5 kg.

2. The method according to claim 1, wherein: Relative to each kilogram of alkylbenzene sulfonic acid, the amount of the calcium-containing alkaline substance is 60-160 g, the amount of the calcium carboxylate is 0.5-2.5 kg, and the total amount of the base oil is 0.5-6 kg.

3. The method according to claim 1 or 2, wherein: The alkalinity value of the alkylbenzene sulfonic acid is 100-180 mgKOH / g.

4. The method according to claim 1 or 2, wherein: The structural formula of the alkylbenzene sulfonic acid is: R1-C6H4-SO3H, wherein R1 is a C10-C24 alkyl group.

5. The method according to claim 4, wherein: The alkylbenzene sulfonic acid is at least one selected from dodecylbenzene sulfonic acid, octadecylbenzene sulfonic acid and tetradecylbenzene sulfonic acid.

6. The method according to claim 1 or 2, wherein: The structural formula of the calcium carboxylate is (R2-COO)2Ca and / or (OOC-R3-COO)Ca, wherein R2 is a substituted or unsubstituted phenyl group, or a substituted or unsubstituted C1-C8 hydrocarbon group, and R3 is a C1-C10 alkylene group.

7. The method according to claim 6, wherein: The substituted group in the calcium carboxylate is a hydroxyl group.

8. The method according to claim 6, wherein: The calcium carboxylate is selected from at least one of calcium acetate, calcium propionate, calcium butyrate, calcium lactate, calcium sorbate, calcium salicylate, calcium sebacate and calcium benzoate.

9. The method according to claim 1 or 2, wherein: The calcium-containing alkaline substance is selected from at least one of calcium hydroxide, calcium carbonate, calcium hydrogen carbonate, calcium phosphate, calcium monohydrogen phosphate and calcium dihydrogen phosphate.

10. The method according to claim 1 or 2, wherein: The weight ratio of the partial base oil to the remaining base oil is 0.5-5.

11. The method according to claim 10, wherein: The weight ratio of the part of the base oil to the balance of the base oil is 1-4.

12. The method according to claim 1 or 2, wherein: The kinematic viscosity of the base oil at 100°C is 2-300 mm 2 / s.

13. The method according to claim 12, wherein: The kinematic viscosity of the base oil at 100°C is 6-100mm 2 / s.

14. Use of the method according to any one of claims 1 to 13 in improving the water resistance of lubricating grease.

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