阅读说明：本技术 一种含氟有机增粘剂及其制备方法 (Fluorine-containing organic tackifier and preparation method thereof ) 是由 刘洋 李倩 辛虎 李杏涛 于 2021-09-14 设计创作，主要内容包括：本发明提供一种含氟有机增粘剂及其制备方法,所述的含氟有机增粘剂是由选自支链型全氟聚醚酰氟、直链型全氟聚醚酰氟以及支链型全氟聚醚羧酸、直链型全氟聚醚羧酸中的一种或多种为原料,在醇试剂中经酯化反应后再与MOH溶液反应制得全氟聚醚羧酸金属盐,其中M选自锂、钠、钾中的一种或几种。本发明为改善氟素润滑脂中基础油和稠化剂之间作用力较弱的现状,同时为进一步扩展全氟聚醚及其衍生物的应用领域,特别开发了一种具有良好稠化作用的含氟有机增粘剂,可用于氟素醚润滑脂的调配,能够有效改进基础油和稠化剂之间的结合力,从而提升氟素润滑脂的胶体安定性。(The invention provides a fluorine-containing organic tackifier and a preparation method thereof, wherein the fluorine-containing organic tackifier is prepared by taking one or more selected from branched perfluoropolyether acyl fluoride, straight-chain perfluoropolyether acyl fluoride, branched perfluoropolyether carboxylic acid and straight-chain perfluoropolyether carboxylic acid as raw materials, carrying out esterification reaction on the raw materials in an alcohol reagent, and then reacting the raw materials with MOH solution to obtain perfluoropolyether carboxylic acid metal salt, wherein M is one or more selected from lithium, sodium and potassium. The invention aims to improve the current situation that the acting force between the base oil and the thickening agent in the fluorine grease is weaker, and further expand the application field of perfluoropolyether and derivatives thereof, and particularly develops a fluorine-containing organic tackifier with good thickening effect, which can be used for blending the fluorine ether grease and can effectively improve the binding force between the base oil and the thickening agent, thereby improving the colloid stability of the fluorine grease.)

1. A fluorine-containing organic tackifier is characterized in that: the metal salt of the branched or straight-chain perfluoropolyether carboxylic acid is shown as the following structural formula:

wherein M in the formulas (III) and (IV) is selected from one or more of Li, Na and K, and M '/n' ═ 20-30; x '/y' is 0.5 to 1.5.

2. The method of preparing a fluorine-containing organic tackifier of claim 1, wherein: the fluorine-containing organic tackifier is prepared by taking one or more selected from branched perfluoropolyether acyl fluoride, straight-chain perfluoropolyether acyl fluoride, branched perfluoropolyether carboxylic acid and straight-chain perfluoropolyether carboxylic acid as raw materials, carrying out esterification reaction on the raw materials in an alcohol reagent, and then reacting the raw materials with MOH solution to obtain perfluoropolyether carboxylic acid metal salt, wherein M is one or more selected from lithium, sodium and potassium; the structural formulas of the branched chain type or straight chain type perfluoropolyether acyl fluoride and the branched chain type or straight chain type perfluoropolyether carboxylic acid are respectively as follows:

wherein the molecular weight of the formula (I) or the formula (II) is 1000-10000; r and R' are at least one of-COF and-COOH; 20-30 m '/n'; x '/y' is 0.5 to 1.5.

3. The method of preparing a fluorine-containing organic tackifier according to claim 2, wherein: (I) the molecular weight of the branched perfluoropolyether acyl fluoride or perfluoropolyether carboxylic acid shown in the formula (I) and the molecular weight of the linear perfluoropolyether carboxylic acid perfluoropolyether acyl fluoride or perfluoropolyether carboxylic acid shown in the formula (II) are both 1500-5000.

4. The method for producing a fluorine-containing organic tackifier according to claim 2 or 3, characterized by: the alcohol reagent is at least one selected from absolute methanol and absolute ethanol, and the mass ratio of the alcohol reagent to the raw material shown in the formula (I) or the formula (II) is 1: 1-1: 20, preferably 1: 2-1: 10.

5. The method for producing a fluorine-containing organic tackifier according to any one of claims 2 to 4, characterized by: the MOH is an aqueous solution with the concentration of 30-40 wt%, and the mass ratio of the esterification reaction product to the MOH solution is 10: 1-3: 1, preferably 7: 1-5: 1.

6. The method for producing a fluorine-containing organic tackifier according to any one of claims 2 to 5, wherein: the perfluoropolyether carboxylic acid metal salt prepared by the reaction is dried and exhausted at the temperature of 100-150 ℃ for later use.

7. The method for producing a fluorine-containing organic tackifier according to any one of claims 2 to 6, characterized by: the method comprises the following steps:

(i) heating the raw material shown in the formula (I) or the formula (II) to 30-100 ℃, keeping the temperature for 30min, dropwise adding an alcohol reagent, stirring, mixing, keeping the temperature at 30-100 ℃, stopping the reaction after reacting for 5-15 h, washing, separating and distilling to obtain a pure esterification intermediate product;

(ii) adding a fluorine solvent and an alcohol reagent into the esterification intermediate product obtained in the step (i), stirring, fully and uniformly mixing, heating to 80-150 ℃, keeping the temperature constant, then adding an MOH solution, continuously stirring, stopping the reaction after the reaction is carried out for 5-15 h, standing for separation, removing a supernatant, washing to be neutral by using the fluorine solvent, the alcohol reagent and deionized water, and filtering to obtain a viscous perfluoropolyether carboxylic acid metal salt precursor;

(iii) and (3) adding the metal salt precursor of perfluoropolyether carboxylic acid in the step (ii) into saturated saline solution, stirring, filtering to obtain colloidal metal salt of perfluoropolyether carboxylic acid (III) or (IV), drying at 100-140 ℃, exhausting, and cooling to obtain the fluorine-containing organic tackifier.

8. The method of preparing the fluorine-containing organic tackifier of claim 7, wherein: the reaction temperature in the step (i) is preferably 60-80 ℃, and the reaction time is preferably 8-12 h; the reaction temperature in the step (ii) is preferably 90-120 ℃, and the reaction time is 9-15 h.

9. The method for producing a fluorine-containing organic tackifier according to claim 7 or 8, characterized by: in the step (III), the metal salt of perfluoropolyether carboxylic acid (III) or (IV) is dried at 100 to 120 ℃ for 4 hours.

10. Use of a fluorine-containing organic adhesion promoter according to claim 1 or a fluorine-containing organic adhesion promoter prepared by a process according to any one of claims 2 to 9, wherein: the fluorine-containing organic tackifier is used for blending fluorine grease.

Technical Field

The invention belongs to the technical field of fluorine-containing lubricating materials, and particularly relates to a fluorine-containing organic tackifier and a preparation method thereof.

Background

Since the 70 s of the 20 th century, the petrochemical lubricating oil company began the research work on the process route of producing perfluoropolyether by photo-oxidative polymerization, and had undergone many technological innovations in the course of decades of development. At present, the perfluoropolyether crude oil independently synthesized by the company is mainly treated by alkali washing, fluorination and other treatment processes to obtain stable-end-capped branched-chain type and straight-chain type perfluoropolyether base oil which is used for producing fluorine lubricating grease products for military industry and civil use.

The perfluoropolyether derivative has characteristics similar to those of perfluoropolyether oil, such as low surface tension, excellent chemical inertness and radiation resistance, good oxidation/thermal stability, incombustibility and the like, so that the perfluoropolyether derivative has wide application value and prospect. CN111100724A discloses perfluoropolyether lubricating grease with good colloid stability and a preparation method thereof, wherein the lubricating grease is composed of base oil (50-95 wt%), a polytetrafluoroethylene thickening agent (1.0-49.9 wt%) and a colloid modifier (0.1-30 wt%), the selected colloid modifier is prepared from fluorine-containing carboxylic acid or fluorine-containing carboxylate through dehydration and saponification, the colloid stability of the perfluoropolyether lubricating grease is improved, but the perfluoropolyether lubricating grease is usually used for long-period lubrication protection under severe environments such as high vacuum and high temperature, and the document does not relate to long-time colloid stability test of the lubricating grease at high temperature, so that the stability effect of the lubricating grease in practical application cannot be predicted.

Disclosure of Invention

The invention provides a fluorine-containing organic tackifier and a preparation method thereof, which aims to improve the colloid stability of fluorine grease and further expand the application field of perfluoropolyether and derivatives thereof. The fluorine-containing organic tackifier provided by the invention has excellent thickening capacity, can be used for blending fluorine grease, and can effectively improve the colloid stability of the fluorine grease.

In order to achieve the above object, the present invention provides a fluorinated organic thickener which is a branched or straight chain metal salt of perfluoropolyether carboxylic acid, and has the following structural formula:

branched chain type

Straight chain type

Wherein M in the formulas (III) and (IV) is selected from one or more of Li, Na and K; m '/n' is 20 to 30, and x '/y' is 0.5 to 1.5.

The second aspect of the present invention provides a method for preparing the above-mentioned fluorine-containing organic tackifier, wherein the fluorine-containing organic tackifier is prepared by using one or more selected from branched perfluoropolyether acyl fluoride, linear perfluoropolyether acyl fluoride, branched perfluoropolyether carboxylic acid, and linear perfluoropolyether carboxylic acid as raw materials, and reacting the raw materials with MOH solution after esterification reaction in an alcohol reagent to obtain metal salt of perfluoropolyether carboxylic acid, wherein M is one or more selected from lithium, sodium, and potassium; the structural formulas of the branched chain type or straight chain type perfluoropolyether acyl fluoride and the branched chain type or straight chain type perfluoropolyether carboxylic acid are respectively as follows:

branched chain type

Straight chain type

Wherein the molecular weight of the formula (I) or the formula (II) is 1000-10000; r and R' are at least one of-COF and-COOH; 20-30 m '/n'; x '/y' is 0.5 to 1.5.

According to the preparation method of the invention, the molecular weight of the branched perfluoropolyether acyl fluoride or perfluoropolyether carboxylic acid represented by the formula (I) and the molecular weight of the linear perfluoropolyether carboxylic acid perfluoropolyether acyl fluoride or perfluoropolyether carboxylic acid represented by the formula (II) are preferably 1500-5000, and are preferably 2600-3500.

According to the preparation method of the present invention, the alcohol reagent is at least one selected from the group consisting of absolute methanol and absolute ethanol. Preferably, the mass ratio of the alcohol reagent to the raw material (I) or (II) is 1:1 to 1:20, preferably 1:2 to 1:10, such as 1:2, 1:5, 1:10, etc.

According to the preparation method, the MOH is an aqueous solution with the concentration of preferably 30-40 wt%, the mass ratio of the esterification reaction product to the MOH solution is 10: 1-3: 1, preferably 7: 1-5: 1, for example: 5:1, 6:1 and 7: 1. The structural formula of the esterification reaction product is as follows: a and A' are-CH₃、-C₂H₅At least one of;

according to the preparation method, the perfluoropolyether carboxylic acid metal salt prepared by the reaction is dried at the temperature of 100-150 ℃ and is exhausted for standby.

The preparation method according to the present invention, in a specific embodiment, comprises the steps of:

(i) heating the raw material shown in the formula (I) or the formula (II) to 30-100 ℃, keeping the temperature for 30min, dropwise adding an alcohol reagent, mechanically stirring and mixing, keeping the temperature at 30-100 ℃, stopping the reaction after reacting for 5-15 h, washing, separating and distilling to obtain a pure esterification intermediate product;

(ii) adding a fluorine solvent and an alcohol reagent into the esterification intermediate product obtained in the step (i), mechanically stirring, fully and uniformly mixing, heating to 80-150 ℃, keeping the temperature constant, then adding an MOH solution, continuously stirring, stopping the reaction after the reaction is carried out for 5-15 h, standing for separation, removing a supernatant, washing to be neutral by using the fluorine solvent, the alcohol reagent and deionized water, and filtering to obtain a yellow and viscous metal salt precursor of perfluoropolyether carboxylate;

(iii) and (3) adding the metal salt precursor of perfluoropolyether carboxylic acid in the step (ii) into saturated saline solution, stirring, filtering to obtain orange yellow colloidal metal salt of perfluoropolyether carboxylic acid (III) or (IV), drying at 100-140 ℃, exhausting, and cooling to obtain the fluorine-containing organic tackifier.

The reaction process is as follows:

(I) and/or (III) and/or (IV)

According to the preparation method, the reaction temperature in the step (i) is preferably 60-80 ℃, and the reaction time is preferably 8-12 h; the reaction temperature in the step (ii) is preferably 90-120 ℃, and the reaction time is 9-15 h.

According to the preparation method of the present invention, the washing in step (i) is neutral by washing with a fluorine solvent and an alcohol reagent.

According to the production method of the present invention, preferably, in the step (III), the metal salt of perfluoropolyether carboxylic acid (III) or (IV) is dried at 100 to 120 ℃ for 4 hours.

The invention also provides application of the fluorine-containing organic tackifier, and the fluorine-containing organic tackifier is used for preparing fluorine grease.

The invention has the following beneficial effects:

the fluorine-containing organic tackifier obtained by the preparation method provided by the invention has good thickening capability, can be used for preparing fluorine grease, can increase the combination effect of base oil and a thickening agent of the grease, effectively improves the colloid stability of the fluorine grease, and further expands the application field of perfluoropolyether and derivatives thereof.

Detailed Description

In order that the technical features and contents of the present invention can be understood in detail, preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention have been described in the examples, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein.

Unless otherwise specified, the starting materials of the examples of the present invention are commercially available.

< test methods >

The following description of the performance testing methods involved or likely to be involved in the examples is as follows:

test items	Test conditions	Unit of	Test standard
				Appearance of the product	—	—	Visual inspection of
Steel mesh oil separation	204℃，24h	％	SH/T 0324
				Pressure oil separation	200g，0.5h	％	GB/T 392

Example 1

(i) Pouring 50g of branched-chain type perfluoropolyether acyl fluoride (average molecular weight is about 3020) into a round-bottom flask, heating to 80 ℃, keeping the temperature constant for 30min, dropwise adding 10g of anhydrous methanol or anhydrous ethanol into the round-bottom flask, mechanically stirring and mixing, keeping the temperature at 80 ℃, stopping the reaction after reacting for 12h, washing the mixture to be neutral by using a fluorine solvent and the anhydrous methanol or the anhydrous ethanol, standing and separating, taking the lower layer of colorless transparent oily liquid, and then carrying out reduced pressure distillation to obtain a pure transparent esterification intermediate product;

(ii) adding a certain amount of fluorine solvent and absolute ethyl alcohol into the esterification intermediate product in the step (i), mechanically stirring, fully and uniformly mixing, heating to 120 ℃, keeping the temperature constant, then adding a proper amount of NaOH solution (the concentration is 40 wt%, and the esterification product is NaOH 6:1), continuously stirring, stopping the reaction after the reaction is 12 hours, standing and separating, removing the supernatant, washing to be neutral by using the fluorine solvent, the absolute ethyl alcohol and deionized water, and filtering to obtain a yellow and viscous metal salt precursor of perfluoropolyether carboxylic acid;

(iii) and (3) adding the metal salt precursor of perfluoropolyether carboxylic acid in the step (ii) into saturated saline solution, stirring, filtering to obtain orange yellow colloidal metal salt of perfluoropolyether carboxylic acid (III), putting into a forced air drying oven, drying for 4 hours at 100 ℃, exhausting, and cooling to obtain the fluorine-containing organic tackifier A.

Example 2

(i) Pouring 50g of branched chain type perfluoropolyether carboxylic acid (the average molecular weight is about 5000) into a round-bottom flask, heating to 80 ℃, keeping the temperature constant for 30min, dropwise adding 5g of anhydrous methanol or anhydrous ethanol into the round-bottom flask, mechanically stirring and mixing, keeping the temperature at 80 ℃, stopping the reaction after reacting for 8h, washing the mixture to be neutral by using a fluorine solvent and the anhydrous methanol or the anhydrous ethanol, standing and separating, taking the lower layer of colorless transparent oily liquid, and then carrying out reduced pressure distillation to obtain a pure and transparent esterification intermediate product;

(ii) adding a certain amount of fluorine solvent and absolute ethyl alcohol into the esterification intermediate product in the step (i), mechanically stirring, fully and uniformly mixing, heating to 120 ℃, keeping the temperature constant, then adding a proper amount of KOH solution (the concentration is 30 wt%, and the esterification product: KOH is 7:1), continuously stirring, stopping the reaction after the reaction is 9 hours, standing and separating, removing the supernatant, washing to be neutral by using the fluorine solvent, the absolute ethyl alcohol and deionized water, and filtering to obtain a yellow and viscous metal salt precursor of perfluoropolyether carboxylic acid;

(iii) and (3) adding the metal salt precursor of perfluoropolyether carboxylic acid in the step (ii) into saturated saline solution, stirring, filtering to obtain orange yellow colloidal metal salt of perfluoropolyether carboxylic acid (III), putting into a forced air drying oven, drying for 4 hours at 120 ℃, exhausting, and cooling to obtain the fluorine-containing organic tackifier B.

Example 3

(i) Pouring 50g of straight-chain perfluoropolyether acyl fluoride (average molecular weight is about 1500) into a round-bottom flask, heating to 60 ℃, keeping the temperature constant for 30min, then adding 25g of anhydrous methanol or anhydrous ethanol into the round-bottom flask drop by drop, mechanically stirring, mixing, keeping the temperature at 60 ℃, stopping the reaction after reacting for 15h, washing the mixture to be neutral by a fluorine solvent and the anhydrous methanol or the anhydrous ethanol, standing and separating, taking the lower layer of colorless transparent oily liquid, and then carrying out reduced pressure distillation to obtain a pure and transparent esterification intermediate product;

(ii) adding a certain amount of fluorine solvent and absolute ethyl alcohol into the esterification intermediate product in the step (i), mechanically stirring, fully and uniformly mixing, heating to 100 ℃, keeping the temperature constant, then adding a proper amount of LiOH solution (the concentration is 40 wt%, and the esterification product: LiOH is 5:1), continuously stirring, stopping the reaction after the reaction is carried out for 15 hours, standing and separating, removing supernatant, washing to be neutral by using the fluorine solvent, the absolute ethyl alcohol and deionized water, and filtering to obtain a yellow viscous metal salt precursor of perfluoropolyether carboxylic acid;

(iii) and (3) adding the metal salt precursor of perfluoropolyether carboxylic acid in the step (ii) into saturated saline solution, stirring, filtering to obtain orange yellow colloidal metal salt of perfluoropolyether carboxylic acid (IV), putting into a forced air drying oven, drying for 4 hours at 100 ℃, exhausting, and cooling to obtain the fluorine-containing organic tackifier C.

Example 4

(i) Pouring 50g of straight-chain type perfluoropolyether carboxylic acid (average molecular weight is about 2650) into a round-bottom flask, heating to 70 ℃, keeping the temperature constant for 30min, adding 20g of anhydrous methanol or anhydrous ethanol dropwise into the round-bottom flask, mechanically stirring and mixing, keeping the temperature at 70 ℃, stopping the reaction after reacting for 12h, washing the mixture to be neutral by using a fluorine solvent and the anhydrous methanol or the anhydrous ethanol, standing and separating, taking the lower layer of colorless transparent oily liquid, and then carrying out reduced pressure distillation to obtain a pure and transparent esterification intermediate product;

(ii) adding a certain amount of fluorine solvent and absolute ethyl alcohol into the esterification intermediate product in the step (i), mechanically stirring, fully and uniformly mixing, heating to 100 ℃, keeping the temperature constant, then adding a proper amount of LiOH solution (the concentration is 40 wt%, and the esterification product: LiOH is 7:1), continuously stirring, stopping the reaction after the reaction is carried out for 15 hours, standing and separating, removing supernatant, washing to be neutral by using the fluorine solvent, the absolute ethyl alcohol and deionized water, and filtering to obtain a yellow viscous metal salt precursor of perfluoropolyether carboxylic acid;

(iii) and (3) adding the metal salt precursor of perfluoropolyether carboxylic acid in the step (ii) into saturated saline solution, stirring, filtering to obtain orange yellow colloidal metal salt of perfluoropolyether carboxylic acid (IV), putting into a forced air drying oven, drying for 4h at 100 ℃, exhausting, and cooling to obtain the fluorine-containing organic tackifier D.

Example 5

(i) Taking 50g of a mixture of branched-chain type perfluoropolyether acyl fluoride (average molecular weight is about 3430) and linear-chain perfluoropolyether carboxylic acid (average molecular weight is about 3150) according to the mass ratio of 3:2, pouring the mixture into a round-bottom flask, heating to 75 ℃, keeping the temperature for 30min, then taking 10g of anhydrous methanol or anhydrous ethanol, dropwise adding the anhydrous methanol or the anhydrous ethanol into the round-bottom flask, mechanically stirring and mixing, keeping the temperature at 75 ℃, stopping the reaction after 10h of reaction, washing the mixture to be neutral by using a fluorine solvent and the anhydrous methanol or the anhydrous ethanol, standing and separating, taking a colorless transparent oily liquid at the lower layer, and then carrying out reduced pressure distillation to obtain a pure esterification intermediate product;

(ii) adding a certain amount of fluorine solvent and absolute ethyl alcohol into the esterification intermediate product in the step (i), mechanically stirring, fully and uniformly mixing, heating to 100 ℃, keeping the temperature constant, then adding a proper amount of NaOH solution (the concentration is 40 wt%, and the esterification product: LiOH is 7:1), continuously stirring, stopping the reaction after the reaction is 15 hours, standing and separating, removing the supernatant, washing to be neutral by using the fluorine solvent, the absolute ethyl alcohol and deionized water, and filtering to obtain a yellow and viscous metal salt precursor of perfluoropolyether carboxylic acid;

(iii) and (3) adding the metal salt precursor of perfluoropolyether carboxylic acid in the step (ii) into saturated saline solution, stirring, filtering to obtain orange yellow colloidal metal salt of perfluoropolyether carboxylic acid (III), putting into a forced air drying oven, drying for 4 hours at 100 ℃, exhausting, and cooling to obtain the fluorine-containing organic tackifier E.

Example 6

(i) Taking 50g of straight-chain type perfluoropolyether acyl fluoride (the average molecular weight is about 5000) and a straight-chain type perfluoropolyether carboxylic acid mixture (the average molecular weight is about 4650), pouring the mixture and the mixture into a round-bottom flask according to the mass ratio of 4:1, heating to 80 ℃, keeping the temperature for 30min, then taking 7.5g of anhydrous methanol or anhydrous ethanol, dropwise adding the anhydrous methanol or the anhydrous ethanol into the round-bottom flask, mechanically stirring and mixing, keeping the temperature at 80 ℃, stopping the reaction after 10h of reaction, washing the mixture to be neutral by using a fluorine solvent and the anhydrous methanol or the anhydrous ethanol, standing and separating, taking a lower layer of colorless transparent oily liquid, and then carrying out reduced pressure distillation to obtain a pure and transparent esterification intermediate product;

(ii) adding a certain amount of fluorine solvent and absolute ethyl alcohol into the esterification intermediate product in the step (i), mechanically stirring, fully and uniformly mixing, heating to 120 ℃, keeping the temperature constant, then adding a proper amount of NaOH solution (the concentration is 35 wt%, and the esterification product is NaOH 7:1), continuously stirring, stopping the reaction after the reaction is 10 hours, standing and separating, removing the supernatant, washing to be neutral by using the fluorine solvent, the absolute ethyl alcohol and deionized water, and filtering to obtain a yellow and viscous metal salt precursor of perfluoropolyether carboxylic acid;

(iii) and (3) adding the metal salt precursor of perfluoropolyether carboxylic acid in the step (ii) into saturated saline solution, stirring, filtering to obtain orange yellow colloidal metal salt of perfluoropolyether carboxylic acid (IV), putting into a forced air drying oven, drying for 4h at 120 ℃, exhausting, and cooling to obtain the fluorine-containing organic tackifier E.

Example 7

Weighing 10g of the fluorine-containing organic tackifier A (the average molecular weight is about 3000) obtained in example 1, and fully bonding the fluorine-containing organic tackifier A with 29.7g of polytetrafluoroethylene thickener; 60.3g of self-produced branched perfluoropolyether base oil (average molecular weight is 2100, kinematic viscosity is 20cst at 40 ℃) is heated to 35 ℃, the temperature is kept constant for 15min, the mixture of the organic tackifier and the thickening agent is slowly added, the mixture is fully stirred for 0.5h, and after cooling, the mixture is ground for 5 times by a three-roll mill, so that the finished lubricating grease is obtained.

Example 8

10g of the fluorine-containing organic tackifier D (having an average molecular weight of about 2600) obtained in example 4 was weighed and sufficiently bonded to 29.7g of a polytetrafluoroethylene thickener; 60.3g of self-produced branched perfluoropolyether base oil (average molecular weight is 2100, kinematic viscosity is 20cst at 40 ℃) is heated to 35 ℃, the temperature is kept constant for 15min, the mixture of the organic tackifier and the thickening agent is slowly added, the mixture is fully stirred for 0.5h, and after cooling, the mixture is ground for 5 times by a three-roll mill, so that the finished lubricating grease is obtained.

Example 9

Weighing 5g of the fluorine-containing organic tackifier E (average molecular weight is about 3200) obtained in example 5 and 31.4g of polytetrafluoroethylene thickener for sufficient adhesion; taking 63.7g of self-produced branched perfluoropolyether base oil (average molecular weight is 2100, kinematic viscosity is 20cst at 40 ℃), heating to 35 ℃, keeping the temperature for 15min, slowly adding the mixture of the organic tackifier and the thickening agent, fully stirring for 0.5h, cooling, and grinding for 5 times by using a three-roll mill to obtain the finished lubricating grease.

Comparative example 1

Taking 67g of self-produced branched perfluoropolyether base oil (average molecular weight is 2100, and kinematic viscosity at 40 ℃ is 20cst), heating to 35 ℃, and keeping the temperature; adding 33g of dried and pretreated polytetrafluoroethylene thickening agent slowly into the base oil, fully stirring for 15min, and cooling to room temperature; and then grinding for 3 times by using a three-roller mill to obtain the finished product of lubricating grease.

The results of the oil separation performance test of the fluorine grease samples obtained in examples 7 to 9 and comparative example 1 are shown in Table 1.

TABLE 1

As shown in Table 1, the fluorine-containing organic tackifiers selected in examples 7 to 9 provided by the present invention were synthesized from branched or/and straight-chain perfluoropolyether acyl fluoride/carboxylic acid having a molecular weight of 2600 to 3500 through a specific reaction route. When the molecular weight of the branched chain type or/and straight chain type perfluoropolyether acyl fluoride/carboxylic acid is lower than 2600, the evaporation degree of the synthesized fluorine-containing organic tackifier blended lubricating grease is too large; when the hardness is more than 3500, the prepared fluorine-containing organic tackifier has overlarge hardness, and the bonding effect with the thickening agent and the base oil is influenced. Because the molecular weight of the straight-chain type perfluoropolyether acyl fluoride is smaller than that of the branched-chain type perfluoropolyether carboxylic acid, when the mass is the same, the acid functional groups contained in the straight-chain type perfluoropolyether acyl fluoride are more, and more alcohol and alkali reagents are consumed in the reaction; in addition, the former can not cause too high reaction temperature due to small molecular weight, thereby avoiding thermal cracking and consuming longer reaction time. Therefore, the raw material ratio, the reaction time and the reaction temperature are reasonably adjusted in the whole reaction process. As can be seen from comparison of performance indexes of comparative examples 7-9 and comparative example 1, the amount of oil separated from the grease added with the fluorine-containing organic tackifier in the examples of the present invention is significantly reduced compared to comparative example 1, which indicates that the tackifier is helpful for improving the colloid stability of the grease, and when the amount of the fluorine-containing organic tackifier is the same, the larger the molecular weight is, the smaller the oil separated amount is. Therefore, the fluorine-containing organic thickener E used in example 9 is preferable.

It is apparent that the above examples and comparative examples of the present invention are based on the examples for better illustrating the present invention and are not limited thereto. For a person skilled in the art, on the basis of the above description, simple modifications may be made, which are not exhaustive of all embodiments, and all obvious modifications which are within the scope of the invention are included in the technical solution of the present invention.