High temperature resistant polypropylene grease and its preparation method

Abstract

This invention relates to the field of lubricating grease technology, and more particularly to a high-temperature resistant polypropylene lubricating grease and its preparation method. The high-temperature resistant polypropylene lubricating grease comprises the following components by weight: 8-20 parts of polypropylene thickener, 75-85 parts of base oil, 5-15 parts of polyurea composition, and 1-5 parts of additives. The polypropylene thickener is a mixture comprising high molecular weight components and low molecular weight components. The high molecular weight components comprise propylene polymers with an average molecular weight greater than 200,000, and the low molecular weight components comprise propylene polymers with an average molecular weight less than 100,000. The polypropylene lubricating grease provided by this invention exhibits excellent high-temperature resistance, effectively meeting the requirements for use at high temperatures. Moreover, the method is simple, easy to implement, and readily applicable.

Description

Technical Field

[0001] This invention relates to the field of lubricating grease technology, and in particular to a high-temperature resistant polypropylene lubricating grease and its preparation method. Background Technology

[0002] Thickeners are an important component of lubricating greases, determining a series of important properties. Polypropylene is a relatively new thickener. Several polypropylene-thickened greases are already available in the prior art. For example, EP95202464A describes a polymer thickener composed of a mixture of a high molecular weight propylene (copolymer- or homopolymer-) polymer and a low molecular weight propylene (copolymer- or homopolymer-) polymer, and also provides a grease composition comprising a base oil and the aforementioned polymer thickener, as well as a method for preparing such a grease composition. CN1057326C discloses a polymer-thickened conductive grease, also using a mixture of a high molecular weight propylene (copolymer- or homopolymer-) polymer and a low molecular weight propylene (copolymer- or homopolymer-) polymer as a thickener, and adding a conductive component; this grease composition exhibits good electrical conductivity. CN104919030A provides a polymer-thickened grease composition and its preparation method, obtaining a polymer-thickened grease composition with improved mechanical stability and good lubrication performance through two mechanical treatments.

[0003] Polypropylene-thickened greases have low dropping points; the grease composition described in EP95202464A has a dropping point of approximately 140°C. There is a need to develop new technologies to improve the dropping point of polypropylene greases to expand their application range. CN1057325C discloses a polymer-thickened grease with improved high-temperature performance, which introduces a high-melting-point component in combination with the "low molecular weight" and "high molecular weight" components described in EP95202464A. The high-melting-point component contains at least one polymer with a melting point greater than 200°C, preferably greater than 225°C. Polypropylene greases have low dropping points and are prone to leakage at high temperatures. The high-temperature performance of existing polypropylene-thickened greases needs improvement, and the methods used are often limited or difficult to implement; therefore, more technological methods are urgently needed. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a high-temperature resistant polypropylene grease and its preparation method. This high-dropping-point polypropylene-thickened grease composition is not easily lost at high temperatures and has the significant advantage of high-temperature resistance. Furthermore, the method of this invention is simple, easy to implement, and readily applicable.

[0005] Specifically, the high-temperature resistant polypropylene grease provided in the first aspect of the present invention comprises the following components by weight: 8-20 parts of polypropylene thickener, 75-85 parts of base oil, 5-15 parts of polyurea composition, and 1-5 parts of additives. The polypropylene thickener is a mixture comprising a high molecular weight component and a low molecular weight component. The high molecular weight component comprises a propylene polymer with an average molecular weight greater than 200,000, and the low molecular weight component comprises a propylene polymer with an average molecular weight less than 100,000.

[0006] In this invention, a mixture of high molecular weight propylene (copolymer- or homopolymer-) polymer and low molecular weight propylene (copolymer- or homopolymer-) polymer is used as a thickener, and a polyurea composition is added to prepare a grease composition with better high temperature resistance and higher dropping point.

[0007] Preferably, the base oil is a PAO base oil; and / or, the kinematic viscosity of the base oil at 40°C is 40~150 mmHg. 2 / s.

[0008] Preferably, the mass ratio of the high molecular weight component to the low molecular weight component is 1:40 to 1:5, more preferably 1:25 to 1:15, and even more preferably 1:20 to 1:18. For example, the weight ratio of high molecular weight polypropylene to low molecular weight polypropylene is 1:21, 1:19.5, 1:19, 1:18.5, 1:17, etc., and any value in between.

[0009] In this invention, the high-temperature resistant polypropylene grease was optimized. By adding a polyurea composition to the grease with a specific polypropylene as a thickener, its high-temperature resistance can be significantly improved.

[0010] Preferably, the high molecular weight component is a propylene homopolymer or a propylene / ethylene copolymer; and / or, the average molecular weight of the high molecular weight component is between 200,000 and 250,000; and / or, the melt flow index of the high molecular weight component is 1.5 to 15, preferably 1.5 to 7.

[0011] More preferably, the low molecular weight component is a propylene homopolymer; and / or, the average molecular weight of the low molecular weight component is between 50,000 and 100,000; and / or, the melt flow index of the low molecular weight component is between 500 and 1,000, preferably between 750 and 1,000.

[0012] In this invention, the high-temperature resistant polypropylene grease provided preferably has a high molecular weight component of propylene homopolymer or propylene / ethylene copolymer, with an average molecular weight between 200,000 and 250,000 and a melt flow index of 1.5 to 15, preferably 1.5 to 7. Simultaneously, the low molecular weight component is preferably a propylene homopolymer, with an average molecular weight between 50,000 and 100,000 and a melt flow index of 500 to 1,000, preferably 750 to 1,000. In this invention, the high-temperature resistant polypropylene grease components with the preferred parameters are simultaneously added to a polyurea composition for interaction, significantly improving the high-temperature resistance of the grease system while also possessing the excellent lubricating properties described in patent application EP95202464A, namely, excellent oil separation characteristics at low temperatures, low noise performance, and mechanical stability.

[0013] Preferably, the polyurea composition comprises the following components in parts by weight: 10-20 parts polyurea and 80-90 parts base oil, wherein the polyurea is obtained by reacting an organic amine with an isocyanate, and the polyurea is preferably a diurea.

[0014] Further preferably, the molar ratio of organic amine to isocyanate is 0.5 to 8:1, more preferably 1.8 to 2.2:1, and even more preferably 2:1.

[0015] Preferably, the organic amine includes octadecylamine and / or aniline, and the isocyanate is a diisocyanate.

[0016] Further preferably, the diurea is selected from one or more of aliphatic polyurea, alicyclic polyurea, and aromatic polyurea.

[0017] Further preferably, the aliphatic polyurea is obtained by reacting octadecylamine with diisocyanate; and / or, the alicyclic polyurea is obtained by reacting cyclohexylamine with diisocyanate; and / or, the aromatic polyurea is obtained by reacting aniline with diisocyanate; preferably, the diisocyanate is 4,4'-diphenylmethane diisocyanate. The polyurea composition used, particularly the preferred diurea types described above, interacts with a polypropylene thickener under specific conditions, contributing to the improvement of overall properties such as high-temperature performance and antioxidant properties.

[0018] Preferably, the additive includes one or more of antioxidants, rust inhibitors, and extreme pressure anti-wear agents, with antioxidants being a preferred component. The additives used in this invention can be of types commonly used in the art.

[0019] Further preferably, the antioxidant is selected from one or more of dialkyldiphenylamine, alkylphenyl-α-naphthylamine, and di-tert-butyl-p-cresol; and / or, the rust inhibitor is selected from one or more of barium petroleum sulfonate, barium dinonylnaphthalene sulfonate, and zinc naphthenate; and / or, the extreme pressure anti-wear agent is selected from one or more of phosphate ester, zinc dialkyldithiophosphate, and isobutylene sulfide. More preferably, the antioxidant is di-tert-butyl-p-cresol.

[0020] Secondly, the method for preparing the high-temperature resistant polypropylene grease provided by the present invention includes: a) The polypropylene thickener is mixed or dissolved in a base oil to obtain a grease composition.

[0021] b) The organic amine solution and isocyanate solution are mixed and reacted to obtain a polyurea composition.

[0022] c) Mix the polyurea composition obtained in step b) with the grease composition, add the additive, stir and perform post-treatment to obtain high-temperature resistant polypropylene grease.

[0023] Preferably, the method for preparing the high-temperature resistant polypropylene grease includes: a) At a temperature higher than the melting point of the polypropylene thickener, the polypropylene thickener is mixed or dissolved in a PAO base oil to obtain a grease composition; the grease composition is rapidly cooled from the mixing or dissolving temperature to room temperature within 1 to 180 seconds.

[0024] b) Dissolve the organic amine and isocyanate separately in the base oil, heat to 45~75℃ to obtain an organic amine solution and an isocyanate solution; mix the organic amine solution and the isocyanate solution and react; heat to 100~150℃, hold at the temperature for 5~30min, cool down to obtain a polyurea composition.

[0025] c) Add the polyurea composition obtained in step b) to the grease composition obtained in step a) at a weight percentage of 5-15%, add the additives, stir for 30-40 minutes, homogenize and degas to obtain high-temperature resistant polypropylene grease. The method provided by this invention is simpler to operate, has milder conditions, and produces a grease with excellent performance, especially under the above-mentioned preferred conditions.

[0026] The beneficial effects of this invention are at least as follows: This invention provides a polypropylene grease with significant advantages in high-temperature resistance and its preparation method, solving the problem that polypropylene greases typically have low dropping points and are difficult to meet the requirements for use at high temperatures. This invention prepares a polypropylene grease with a dropping point greater than 160°C, preferably greater than 180°C, by adding a polyurea composition to traditional polypropylene grease, making it suitable for high-temperature operating conditions. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] Unless otherwise stated, all raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods. Where specific techniques or conditions are not specified in the examples, they are performed using conventional methods or in accordance with techniques or conditions described in the literature in this field, or according to the product instructions. Reagents and instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0029] Example 1 This embodiment provides a high-temperature resistant polypropylene grease and its preparation method, which includes the following steps: mixing specific amounts of high molecular weight polypropylene (average molecular weight 230,000, melt flow index 3.5), low molecular weight polypropylene (average molecular weight 82,000, melt flow index 800), and PAO base oil (viscosity 68 mmHg at 40℃). 2 The mixture was heated to 190°C until the polypropylene was completely dissolved. The weight ratio of high molecular weight polypropylene to low molecular weight polypropylene was 1:19. The resulting polypropylene grease composition was rapidly cooled to room temperature in about 1 minute. Octadecylamine was added to 1 / 2 base oil (viscosity 68 mmHg at 40°C). 2 In a solution of 4,4'-diphenylmethane diisocyanate, heat to 65±5℃; add 4,4'-diphenylmethane diisocyanate to the remaining 1 / 2 base oil (viscosity 68 mm at 40℃). 2 In a solution containing octadecylamine and 4,4'-diphenylmethane diisocyanate, the temperature is raised to 50±5℃. After complete dissolution, the organic amine solution and isocyanate solution are mixed (molar ratio of octadecylamine to 4,4'-diphenylmethane diisocyanate is 2:1) and reacted. The temperature is raised to 140℃ and held for 10 min. After the holding time is completed, the temperature is lowered to obtain the polyurea composition. The specific composition of each component of the polyurea composition is shown in Table 1. The polyurea composition is added to the polypropylene grease composition at a weight percentage of 5%, and the antioxidant di-tert-butyl-p-cresol is added. The mixture is stirred for 35±5 min to homogenize and degas, and the final finished grease is obtained. The specific types and proportions of each component of the high-temperature resistant polypropylene grease provided in this embodiment are shown in Table 2.

[0030] Example 2 This embodiment provides a high-temperature resistant polypropylene grease and its preparation method, which includes the following steps: mixing specific amounts of high molecular weight polypropylene (average molecular weight 230,000, melt flow index 3.5), low molecular weight polypropylene (average molecular weight 82,000, melt flow index 800), and PAO base oil (viscosity 68 mmHg at 40℃). 2 The mixture was heated to 190°C until the polypropylene was completely dissolved. The weight ratio of high molecular weight polypropylene to low molecular weight polypropylene was 1:19. The resulting grease mixture was rapidly cooled to room temperature in about 1 minute. Octadecylamine was added to 1 / 2 base oil (viscosity 68 mmHg at 40°C). 2 In a solution of 4,4'-diphenylmethane diisocyanate, heat to 65±5℃; add 4,4'-diphenylmethane diisocyanate to the remaining 1 / 2 base oil (viscosity 68 mm at 40℃). 2 In a solution containing octadecylamine and 4,4'-diphenylmethane diisocyanate, the temperature is raised to 50±5℃. After complete dissolution, the organic amine solution and isocyanate solution are mixed (the molar ratio of octadecylamine to 4,4'-diphenylmethane diisocyanate is 2:1) and reacted. The temperature is raised to 140℃ and held for 10 minutes. After the holding time is completed, the temperature is lowered to obtain the polyurea composition. The specific composition of each component of the polyurea composition is shown in Table 1. The polyurea composition is added to the polypropylene grease composition at a weight percentage of 10%, and the antioxidant di-tert-butyl-p-cresol is added. The mixture is stirred for 35±5 minutes to homogenize and degas, and the final finished grease is obtained. The specific types and proportions of each component of the high-temperature resistant polypropylene grease provided in this embodiment are shown in Table 2.

[0031] Example 3 This embodiment provides a high-temperature resistant polypropylene grease and its preparation method, which includes the following steps: mixing specific amounts of high molecular weight polypropylene (average molecular weight 230,000, melt flow index 3.5), low molecular weight polypropylene (average molecular weight 82,000, melt flow index 800), and PAO base oil (viscosity 68 mmHg at 40℃). 2 The mixture was heated to 190°C until the polypropylene was completely dissolved. The weight ratio of high molecular weight polypropylene to low molecular weight polypropylene was 1:19. The resulting grease mixture was rapidly cooled to room temperature in about 1 minute. Aniline was added to 1 / 2 base oil (viscosity 68 mmHg at 40°C). 2 In a solution of 4,4'-diphenylmethane diisocyanate, heat to 55±5℃; add 4,4'-diphenylmethane diisocyanate to the remaining 1 / 2 base oil (viscosity 68 mm at 40℃). 2In a solution containing aniline and 4,4'-diphenylmethane diisocyanate, the temperature is raised to 50±5℃. After complete dissolution, the organic amine solution and isocyanate solution are mixed and reacted (the molar ratio of aniline to 4,4'-diphenylmethane diisocyanate is 2:1). The temperature is raised to 150℃ and held for 10 minutes. After the holding time is completed, the temperature is lowered to obtain the polyurea composition. The specific composition of each component of the polyurea composition is shown in Table 1. The polyurea composition is added to the polypropylene grease composition at a weight percentage of 5%, and the antioxidant di-tert-butyl-p-cresol is added. The mixture is stirred for 35±5 minutes to homogenize and degas, and the final finished grease is obtained. The specific types and proportions of each component of the high-temperature resistant polypropylene grease provided in this embodiment are shown in Table 2.

[0032] Example 4 This embodiment provides a high-temperature resistant polypropylene grease and its preparation method, which includes the following steps: mixing specific amounts of high molecular weight polypropylene (average molecular weight 230,000, melt flow index 3.5), low molecular weight polypropylene (average molecular weight 82,000, melt flow index 800), and PAO base oil (viscosity 68 mmHg at 40℃). 2 The mixture was heated to 190°C until the polypropylene was completely dissolved. The weight ratio of high molecular weight polypropylene to low molecular weight polypropylene was 1:19. The resulting grease mixture was rapidly cooled to room temperature in about 1 minute. Aniline was added to 1 / 2 base oil (viscosity 68 mmHg at 40°C). 2 In a solution of 4,4'-diphenylmethane diisocyanate, heat to 55±5℃; add 4,4'-diphenylmethane diisocyanate to the remaining 1 / 2 base oil (viscosity 68 mm at 40℃). 2 In a solution containing aniline ( / s), the temperature is raised to 50±5℃; after complete dissolution, the above organic amine solution and isocyanate solution are mixed and reacted (the molar ratio of aniline to 4,4'-diphenylmethane diisocyanate is 2:1); the temperature is raised to 150℃ and held for 10 min. After the holding time is completed, the temperature is lowered to obtain the polyurea composition. The specific component ratios of the polyurea composition are shown in Table 1. The polyurea composition is added to the polypropylene grease composition at a weight percentage of 10%, and the antioxidant di-tert-butyl-p-cresol is added. The mixture is stirred for 35±5 min to homogenize and degas, obtaining the final finished grease. The specific types and ratios of the components of the high-temperature resistant polypropylene grease provided in this embodiment are shown in Table 2.

[0033] Comparative Example 1 A specific amount of high molecular weight polypropylene (average molecular weight 230,000, melt flow index 3.5), low molecular weight polypropylene (average molecular weight 82,000, melt flow index 800), and PAO base oil (viscosity 68 mmHg at 40°C) were blended. 2The mixture was heated to 190°C until the polypropylene was completely dissolved. The weight ratio of high molecular weight polypropylene to low molecular weight polypropylene was 1:19. The resulting grease mixture was rapidly cooled to room temperature in about 1 minute. The antioxidant di-tert-butyl-p-cresol was added, and stirring was continued for 35 ± 5 minutes for homogenization and degassing to obtain the final finished grease. The specific types and proportions of each component are shown in Table 2.

[0034] Table 1. Polyurea Composition Ratios in Examples

[0035] Table 2. Formulation of grease compositions in the examples and comparative examples

[0036] This invention uses the GB / T 269 test method to determine the working cone penetration of lubricating grease samples. The GB / T 3498 method is used to determine the dropping point of the lubricating grease samples. The SH / T 0790 method is used to determine the antioxidant properties of the lubricating grease, with the experimental conditions being: 190℃, argon gas at 35 bar, and oxygen flow rate at 100 ml / min.

[0037] The performance test results of the grease samples in the examples and comparative examples are shown in Table 3.

[0038] Table 3 Test results of the examples and comparative examples

[0039] As can be seen from the data in Table 3, compared with the comparative examples, the polypropylene grease provided by the present invention has a significantly higher dropping point and improved antioxidant properties in Examples 1-4. The polypropylene grease composition prepared according to the present invention has the significant advantage of high temperature resistance and can meet the requirements for use at high temperatures.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-temperature resistant polypropylene grease, characterized in that, The product comprises the following components by weight: 8-20 parts of polypropylene thickener, 75-85 parts of base oil, 5-15 parts of polyurea composition, and 1-5 parts of additives. The polypropylene thickener is a mixture of high molecular weight components and low molecular weight components. The high molecular weight components comprise propylene polymers with an average molecular weight greater than 200,000, and the low molecular weight components comprise propylene polymers with an average molecular weight less than 100,000.

2. The high-temperature resistant polypropylene grease according to claim 1, characterized in that, The base oil is a PAO base oil; and / or, the kinematic viscosity of the base oil at 40°C is 40~150 mmHg. 2 / s.

3. The high-temperature resistant polypropylene grease according to claim 1 or 2, characterized in that, The mass ratio of the high molecular weight component to the low molecular weight component is 1:40 to 1:5, preferably 1:25 to 1:15, and more preferably 1:20 to 1:

18.

4. The high-temperature resistant polypropylene grease according to any one of claims 1-3, characterized in that, The high molecular weight component is a propylene homopolymer or a propylene / ethylene copolymer; and / or, the average molecular weight of the high molecular weight component is between 200,000 and 250,000; and / or, the melt flow index of the high molecular weight component is 1.5 to 15, preferably 1.5 to 7.

5. The high-temperature resistant polypropylene grease according to any one of claims 1-4, characterized in that, The low molecular weight component is a propylene homopolymer; and / or, the average molecular weight of the low molecular weight component is between 50,000 and 100,000; and / or, the melt flow index of the low molecular weight component is between 500 and 1,000, preferably between 750 and 1,000.

6. The high-temperature resistant polypropylene grease according to any one of claims 1-5, characterized in that, The polyurea composition comprises the following components in parts by weight: 10-20 parts polyurea and 80-90 parts base oil, wherein the polyurea is obtained by reacting an organic amine and an isocyanate, preferably a diurea; preferably, the molar ratio of the organic amine to the isocyanate is 0.5-8:1, more preferably 1.8-2.2:1, and more preferably 2:

1.

7. The high-temperature resistant polypropylene grease according to claim 6, characterized in that, The diurea is selected from one or more of aliphatic polyurea, alicyclic polyurea, and aromatic polyurea.

8. The high-temperature resistant polypropylene grease according to claim 7, characterized in that, The aliphatic polyurea is obtained by reacting octadecylamine with diisocyanate; and / or, the alicyclic polyurea is obtained by reacting cyclohexylamine with diisocyanate; and / or, the aromatic polyurea is obtained by reacting aniline with diisocyanate; preferably, the diisocyanate is 4,4'-diphenylmethane diisocyanate.

9. The high-temperature resistant polypropylene grease according to any one of claims 1-8, characterized in that, The additive includes one or more of antioxidants, rust inhibitors, and extreme pressure anti-wear agents; preferably, the antioxidant is selected from one or more of dialkyldiphenylamine, alkylphenyl-α-naphthylamine, and di-tert-butyl-p-cresol; and / or, the rust inhibitor is selected from one or more of barium petroleum sulfonate, barium dinonylnaphthalene sulfonate, and zinc naphthenate; and / or, the extreme pressure anti-wear agent is selected from one or more of phosphate esters, zinc dialkyldithiophosphate, and isobutylene sulfide.

10. A method for preparing the high-temperature resistant polypropylene grease according to any one of claims 1-9, characterized in that, Includes the following steps: a) Mixing or dissolving the polypropylene thickener in a base oil to obtain a grease composition; b) The organic amine solution and the isocyanate solution are mixed and reacted to obtain a polyurea composition; c) Mix the polyurea composition obtained in step b) with the grease composition, add the additive, stir and perform post-treatment to obtain high-temperature resistant polypropylene grease; Preferably, it includes the following steps: a) At a temperature higher than the melting point of the polypropylene thickener, the polypropylene thickener is mixed or dissolved in a PAO base oil to obtain a grease composition; the grease composition is rapidly cooled from the mixing or dissolving temperature to room temperature within 1 to 180 seconds. b) Dissolve the organic amine and isocyanate separately in the base oil, heat to 45~75℃ to obtain an organic amine solution and an isocyanate solution; mix the organic amine solution and the isocyanate solution and react; heat to 100~150℃, hold at the temperature for 5~30min, cool down to obtain a polyurea composition; c) Add the polyurea composition obtained in step b) to the grease composition obtained in step a) at a weight percentage of 5-15%, add the additive, stir for 30-40 minutes, homogenize and degas to obtain high-temperature resistant polypropylene grease.

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