Preparation method of composite lubricant

Abstract

The invention relates to a preparation method of a composite lubricant. The method comprises the following steps: 1) preparing an electropositive polysaccharide aqueous solution; 2) preparing an electronegative polysaccharide aqueous solution; 3) mixing an emulsifier and a lubricant to obtain a core material dispersion liquid; 4) mixing the core material dispersion liquid with an electronegative polysaccharide aqueous solution, and emulsifying to obtain an emulsion; 5) dropwise adding the emulsion into an electropositive polysaccharide aqueous solution, adding a calcium chloride aqueous solution, dispersing to obtain a primary microcapsule emulsion, and drying the primary microcapsule emulsion to obtain a primary microcapsule; (6) mixing the primary microcapsule with a mixed solution of ammonia water and ethanol, stirring, condensing and refluxing to obtain a primary microcapsule dispersion liquid; 7) dissolving tetraethoxysilane in absolute ethyl alcohol to obtain a tetraethoxysilane solution, dropwise adding the tetraethoxysilane solution into the primary microcapsule dispersion liquid, and reacting to obtain a microcapsule dispersion liquid; and 8) carrying out suction filtration, washing and drying on the microcapsule dispersion liquid to obtain the composite lubricant.

Description

Technical Field

[0001] The invention relates to the field of oilfield chemistry, and in particular to a method for preparing a composite lubricant. Background Art

[0002] At present, the world's drilling technology is developing rapidly, and the demand for special drilling such as horizontal wells, extended reach wells and ultra-deep wells has increased sharply. Conventional lubricants are gradually unable to meet the requirements of today's special drilling. For example, when drilling horizontally, the lubrication efficiency of traditional lubricants is low; when operating in deep wells and ultra-deep wells, the high temperature and high pressure conditions underground will affect the performance of lubricants used in drilling fluids. Under such circumstances, microcapsule lubricants came into being. However, the existing microcapsules have poor sealing performance, low mechanical strength, and insufficient temperature resistance. Summary of the invention

[0003] One of the present inventions provides a method for preparing a composite lubricant, which comprises the following steps:

[0004] 1) dissolving a positively charged polysaccharide in water to obtain a positively charged polysaccharide aqueous solution;

[0005] 2) dissolving the negatively charged polysaccharide in water to obtain a negatively charged polysaccharide aqueous solution;

[0006] 3) mixing the lipophilic emulsifier and the hydrophilic emulsifier to obtain a mixed emulsifier, and mixing the mixed emulsifier with the core material to obtain a core material dispersion;

[0007] 4) mixing the core material dispersion with the negatively charged polysaccharide aqueous solution, emulsifying, and obtaining an emulsion;

[0008] 5) adding the emulsion dropwise to the positively charged polysaccharide aqueous solution, then adding calcium chloride aqueous solution, dispersing to obtain a primary microcapsule emulsion, and then drying the primary microcapsule emulsion to obtain primary microcapsules;

[0009] 6) mixing the primary microcapsules with a mixed solution of ammonia water and ethanol (i.e., a mixed solution of ammonia water and ethanol), stirring and condensing and refluxing to obtain a primary microcapsule dispersion;

[0010] 7) dissolving tetraethyl orthosilicate in anhydrous ethanol to obtain an ethanol solution of tetraethyl orthosilicate, and then dropwise adding the ethanol solution of tetraethyl orthosilicate into the primary microcapsule dispersion to react and obtain a microcapsule dispersion;

[0011] 8) filtering, washing and drying the microcapsule dispersion to obtain the composite lubricant.

[0012] In a specific embodiment, the positively charged polysaccharide is chitosan and / or gum arabic.

[0013] In a specific embodiment, the negatively charged polysaccharide is sodium alginate and / or calcium alginate.

[0014] In a specific embodiment, the lipophilic emulsifier is Span-80 and / or Span-60.

[0015] In a specific embodiment, the hydrophilic emulsifier is at least one of Tween-80, Tween-60, OP-10, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and cetyltrimethylammonium bromide (CTAB).

[0016] In a specific embodiment, the core material is at least one of peanut oil, soybean oil, biodiesel, white oil and polyether polyol.

[0017] In a specific embodiment, the white oil is 3# white oil.

[0018] In a specific embodiment, the amount of the positively charged polysaccharide is 3 to 6 parts by mass, the amount of the negatively charged polysaccharide is 3 to 6 parts by mass, the amount of the lipophilic emulsifier is 1 part by mass, the amount of the hydrophilic emulsifier is 1.5 to 3 parts by mass, and the amount of the core material is 4 to 5 parts by mass.

[0019] In a specific embodiment, the ratio of the total mass of the positively charged polysaccharide and the negatively charged polysaccharide to the mass of the core material is 0.8:1 to 8:1; preferably, the ratio of the total mass of the positively charged polysaccharide and the negatively charged polysaccharide to the mass of the core material is 1:1 to 6:1; preferably, the ratio of the total mass of the positively charged polysaccharide and the negatively charged polysaccharide to the mass of the core material is 1:1 to 3:1.

[0020] In a specific embodiment, the mass ratio of the lipophilic emulsifier to the hydrophilic emulsifier is 1:(1-5), preferably 1:(1-3.5), and more preferably 1:(1.5-3).

[0021] In a specific embodiment, the mass / volume ratio of the primary microcapsules to the tetraethyl orthosilicate is 1 g:(5 to 10 mL), preferably 1 g:(5 to 8 mL).

[0022] In a specific embodiment, in step 1), the mass content of the positively charged polysaccharide in the positively charged polysaccharide aqueous solution is 1% to 5%, preferably 1.5% to 4.5%, and more preferably 1.5% to 3%.

[0023] In a specific embodiment, in step 2), the mass content of the negatively charged polysaccharide in the negatively charged polysaccharide aqueous solution is 1% to 5%, preferably 1.5% to 4.5%, and more preferably 1.5% to 3%.

[0024] In a specific embodiment, the volume ratio of the tetraethyl orthosilicate to the anhydrous ethanol is (0.5-1):1; and the reaction time is 16 to 24 hours.

[0025] In a specific embodiment, in step 3), the lipophilic emulsifier and the hydrophilic emulsifier are stirred and dispersed using an emulsifying shearing machine to obtain the mixed emulsifier, and the mixed emulsifier and the core material are stirred and dispersed using an emulsifying shearing machine and then ultrasonically dispersed to obtain the core material dispersion.

[0026] In a specific embodiment, in step 4), the core material dispersion and the negatively charged polysaccharide aqueous solution are stirred and emulsified using an emulsifying shearing machine to obtain the emulsion.

[0027] In one specific embodiment, in step 5), the primary microcapsule emulsion is dried using a spray dryer, the inlet air temperature of the spray dryer is 120 to 210°C, and the feed rate is 300 to 500 mL / h; preferably, the inlet air temperature is 150 to 200°C, and more preferably, the inlet air temperature is 160 to 195°C.

[0028] In a specific embodiment, in step 6), the stirring and condensation reflux time is 20 to 30 minutes.

[0029] In a specific embodiment, in step 8), the filtered product is washed with anhydrous ethanol and dried at 55 to 65° C. for 10 to 12 hours.

[0030] In a specific embodiment, the content of calcium chloride in the primary microcapsule emulsion is 0.73 wt % to 0.75 wt %.

[0031] Beneficial effects of the present invention:

[0032] The present invention adopts a composite coagulation-spray drying-sol-gel method to prepare an environmentally friendly high-temperature resistant composite lubricant. The composite lubricant has the advantage of storage stability and effectively solves the problem that the core lubricant in the microcapsule lubricant is seriously lost as the storage time increases; at the same time, according to the performance index data of elastic modulus and temperature resistance, it can be known that the silicon dioxide coating of the composite lubricant can effectively increase the rigidity of the biopolysaccharide capsule wall and improve the compression and shear resistance of the lubricant; at the same time, the silicon dioxide coating has a good heat insulation effect, which can slow down the heating speed of the biopolysaccharide capsule wall and the core material, so that the composite lubricant can resist a high temperature of 160°C. DETAILED DESCRIPTION

[0033] The above contents of the present invention are further described in detail below in the form of preferred implementation cases, but they do not constitute a limitation to the present invention.

[0034] Unless otherwise specified, the reagents in the embodiments of the present invention can be purchased through commercial channels.

[0035] Example 1

[0036] 1) Weigh 3 g of chitosan and add it to 200 mL of deionized water under magnetic stirring, add acetic acid dropwise until the solution becomes transparent, and stir for 10 min to obtain a 1.5% chitosan solution.

[0037] 2) Weigh 3 g of sodium alginate, add it into 200 mL of distilled water at 11000 r / min, and stir for 20 min to obtain a 1.5% sodium alginate solution.

[0038] 3) Weigh 1 g of Span-80 and 1.5 g of Tween-80, mix the two, and stir them at a high speed of 11000 r / min for 10 min using an emulsifying shearing machine, add 4 g of peanut oil, continue stirring at a high speed of 11000 r / min for 5 min, and ultrasonically disperse for 10 min to obtain a core material dispersion.

[0039] 4) The core material dispersion was mixed with the sodium alginate solution, and high-speed shearing was performed at a speed of 11000 r / min for 5 min using an emulsifying shearing machine to obtain an emulsion.

[0040] 5) adding the emulsion dropwise to the chitosan solution stirred at a stirring speed of 3000 r / min, stirring continuously for 30 min, adding 33.33 g of a 10 wt % CaCl2 aqueous solution, stirring continuously for 30 min, and obtaining a primary microcapsule emulsion (the content of CaCl2 therein is 0.75 wt %); spray drying the primary microcapsule emulsion at a feed speed of 300 mL / h, a fan efficiency of 30%, and a temperature of 160° C. to obtain primary microcapsules.

[0041] 6) Weigh 1.0 g of primary microcapsules and add them into a three-necked flask containing 100 mL of ammonia water (aqueous solution with an NH3 content of 25 wt%) and a mixed solution of anhydrous ethanol (including 10 mL of ammonia water and 90 mL of anhydrous ethanol), stir mechanically at a speed of 300 r / min and condense and reflux at 60° C. for 30 min to obtain a primary microcapsule dispersion.

[0042] 7) Take 5 mL of tetraethyl orthosilicate (TEOS) and dissolve it in 10 mL of anhydrous ethanol to obtain an ethanol solution of tetraethyl orthosilicate. Use a rubber-tipped dropper to slowly add the ethanol solution of tetraethyl orthosilicate to the primary microcapsule dispersion at 60°C. Stir and react at 60°C at a speed of 200 r / min for 24 hours to obtain a microcapsule dispersion.

[0043] 8) The microcapsule dispersion was filtered, and then the filter cake was washed three times with anhydrous ethanol and dried by air at 55° C. for 10 h to obtain the composite lubricant.

[0044] Example 2

[0045] 1) Weigh 6 g of gum arabic and add it to 200 mL of deionized water under magnetic stirring, add acetic acid dropwise until the solution becomes transparent, and stir for 10 min to obtain a 3% gum arabic solution.

[0046] 2) Weigh 6 g of sodium alginate, add it into 200 mL of distilled water at 11000 r / min, and stir for 20 min to obtain a 3% sodium alginate solution.

[0047] 3) Weigh 1 g of Span-60 and 3 g of sodium dodecyl sulfate, mix the two, and stir them at a high speed of 11000 r / min for 10 min using an emulsifying shearing machine, add 4 g of soybean oil, stir at a high speed of 11000 r / min for 5 min, and ultrasonically disperse for 10 min to obtain a core material dispersion.

[0048] 4) The core material dispersion was mixed with the sodium alginate solution, and high-speed shearing was performed at a speed of 11000 r / min for 5 min using an emulsifying shearing machine to obtain an emulsion.

[0049] 5) adding the emulsion dropwise to the gum arabic solution stirred at a stirring speed of 3000 r / min, stirring continuously for 30 min, then adding 33.33 g of a 10 wt% CaCl2 aqueous solution, stirring continuously for 30 min, to obtain a primary microcapsule emulsion (the content of CaCl2 therein is 0.73 wt%); spray drying the primary microcapsule emulsion at a feed rate of 500 mL / h, a fan efficiency of 30%, and a temperature of 195° C. to obtain primary microcapsules.

[0050] 6) Weigh 1.0 g of primary microcapsules and add them into a three-necked flask containing 100 mL of ammonia water (aqueous solution with an NH3 content of 25 wt%) and a mixed solution of ethanol (including 10 mL of ammonia water and 90 mL of ethanol), and reflux at 60° C. for 30 min under mechanical stirring at a speed of 300 r / min to obtain a primary microcapsule dispersion.

[0051] 7) Take 10 mL of TEOS and dissolve it in 10 mL of anhydrous ethanol to obtain an ethanol solution of tetraethyl orthosilicate, and slowly add the ethanol solution of tetraethyl orthosilicate to the primary microcapsule dispersion at 60° C. using a rubber-tipped dropper, and continue the reaction at 60° C. at a speed of 400 r / min for 24 hours to obtain a microcapsule dispersion.

[0052] 8) The microcapsule dispersion was filtered, and then the filter cake was washed three times with anhydrous ethanol and dried by air at 55° C. for 10 h to obtain the composite lubricant.

[0053] Example 3

[0054] 1) Weigh 4 g of gum arabic and add it to 200 mL of deionized water under magnetic stirring, add acetic acid dropwise until the solution becomes transparent, and stir for 10 min to obtain a 2% gum arabic solution.

[0055] 2) Weigh 4 g of sodium alginate, add it into 200 mL of distilled water at 11000 r / min, and stir for 20 min to obtain a 2% sodium alginate solution.

[0056] 3) Weigh 1 g of Span-80 and 2 g of sodium dodecylbenzene sulfonate, mix the two, and stir them at a high speed of 11000 r / min for 10 min using an emulsifying shearing machine, add 4 g of soybean oil, stir at a high speed of 11000 r / min for 5 min, and ultrasonically disperse for 10 min to obtain a core material dispersion.

[0057] 4) The core material dispersion was mixed with the sodium alginate solution, and high-speed shearing was performed at a speed of 11000 r / min for 5 min using an emulsifying shearing machine to obtain an emulsion.

[0058] 5) adding the emulsion dropwise to the gum arabic solution stirred at a stirring speed of 3000 r / min, stirring continuously for 30 min, adding 33.33 g of a 10 wt% CaCl2 aqueous solution, stirring continuously for 30 min, and obtaining a primary microcapsule emulsion (the content of CaCl2 therein is 0.74 wt%); spray drying the primary microcapsule emulsion at a feed rate of 400 mL / h, a fan efficiency of 30%, and a temperature of 170° C. to obtain primary microcapsules.

[0059] 6) Weigh 1.0 g of primary microcapsules and add them into a three-necked flask containing 100 mL of ammonia water (aqueous solution with an NH3 content of 25 wt%) and a mixed solution of ethanol (including 10 mL of ammonia water and 90 mL of ethanol), and reflux at 60° C. for 30 min under mechanical stirring at a speed of 300 r / min to obtain a primary microcapsule dispersion.

[0060] 7) Take 8 mL of TEOS and dissolve it in 10 mL of anhydrous ethanol to obtain an ethanol solution of tetraethyl orthosilicate, and slowly add the ethanol solution of tetraethyl orthosilicate to the primary microcapsule dispersion at 60° C. using a rubber-tipped dropper, and continue the reaction at 60° C. at a speed of 300 r / min for 24 hours to obtain a microcapsule dispersion.

[0061] 8) The microcapsule dispersion was filtered, and then the filter cake was washed three times with anhydrous ethanol and dried by air at 55° C. for 10 h to obtain the composite lubricant.

[0062] Example 4

[0063] 1) Weigh 5 g of gum arabic and add it to 200 mL of deionized water under magnetic stirring, add acetic acid dropwise until the solution becomes transparent, and stir for 10 min to obtain a 2.5% gum arabic solution.

[0064] 2) Weigh 5 g of sodium alginate, add it into 200 mL of distilled water at 11000 r / min, and stir for 20 min to obtain a 2.5% sodium alginate solution.

[0065] 3) Weigh 1 g of Span-80 and 1.5 g of sodium dodecylbenzene sulfonate, mix the two, and stir them at a high speed of 11000 r / min for 10 min using an emulsifying shearing machine, add 5 g of 3# white oil, stir at a high speed of 11000 r / min for 5 min, and ultrasonically disperse for 10 min to obtain a core material dispersion.

[0066] 4) The core material dispersion was mixed with the sodium alginate solution, and high-speed shearing was performed at a speed of 11000 r / min for 5 min using an emulsifying shearing machine to obtain an emulsion.

[0067] 5) adding the emulsion dropwise to the gum arabic solution stirred at a stirring speed of 3000 r / min, stirring continuously for 30 min, adding 33.33 g of a 10 wt% CaCl2 aqueous solution, stirring continuously for 30 min, and obtaining a primary microcapsule emulsion (the content of CaCl2 therein is 0.74 wt%); spray drying the primary microcapsule emulsion at a feed rate of 450 mL / h, a fan efficiency of 30%, and a temperature of 185° C. to obtain primary microcapsules.

[0068] 6) 1.0 g of primary microcapsules were added into a three-necked flask containing 100 mL of ammonia water (aqueous solution with an NH3 content of 25 wt%) and a mixed solution of ethanol (including 10 mL of ammonia water and 90 mL of ethanol), and condensed and refluxed at 60° C. for 30 min under mechanical stirring at a speed of 300 r / min to obtain a primary microcapsule dispersion.

[0069] 7) Take 9 mL of TEOS and dissolve it in 10 mL of anhydrous ethanol to obtain an ethanol solution of tetraethyl orthosilicate. Use a rubber-tipped dropper to slowly add the ethanol solution of tetraethyl orthosilicate to the primary microcapsule dispersion at 60° C., stir and react at 60° C. at a speed of 300 r / min for 24 hours to obtain a microcapsule dispersion.

[0070] 8) The microcapsule dispersion was filtered, and then the filter cake was washed three times with anhydrous ethanol and dried by air at 55° C. for 10 h to obtain the composite lubricant.

[0071] Example 5

[0072] 1) Weigh 5 g of chitosan and add it to 200 mL of deionized water under magnetic stirring, add acetic acid dropwise until the solution becomes transparent, and stir for 10 min to obtain a 2.5% chitosan solution.

[0073] 2) Weigh 5 g of calcium alginate, add it into 200 mL of distilled water at 11000 r / min, and stir for 20 min to obtain a 2.5% calcium alginate solution.

[0074] 3) Weigh 1 g of Span-80 and 1.5 g of sodium dodecylbenzene sulfonate, mix the two, and stir them at a high speed of 11000 r / min for 10 min using an emulsifying shearing machine, add 5 g of 3# white oil, stir at a high speed of 11000 r / min for 5 min, and ultrasonically disperse for 10 min to obtain a core material dispersion.

[0075] 4) The core material dispersion was mixed with the calcium alginate solution, and high-speed shearing was performed at a speed of 11000 r / min for 5 min using an emulsifying shearing machine to obtain an emulsion.

[0076] 5) adding the emulsion dropwise to the chitosan solution stirred at a stirring speed of 3000 r / min, stirring continuously for 30 min, adding 33.33 g of 10 wt % CaCl2 aqueous solution, stirring continuously for 30 min, to obtain a primary microcapsule emulsion; spray drying the primary microcapsule emulsion at a feed rate of 450 mL / h, a fan efficiency of 30%, and a temperature of 185° C. to obtain primary microcapsules.

[0077] 6) 1.0 g of primary microcapsules were added into a three-necked flask containing 100 mL of ammonia water (aqueous solution with an NH3 content of 25 wt%) and a mixed solution of ethanol (including 10 mL of ammonia water and 90 mL of ethanol), and condensed and refluxed at 60° C. for 30 min under mechanical stirring at a speed of 300 r / min to obtain a primary microcapsule dispersion.

[0078] 7) Take 9 mL of TEOS and dissolve it in 10 mL of anhydrous ethanol, and slowly add it dropwise into the primary microcapsule dispersion at 60° C. using a rubber-tipped dropper, and continue the reaction at 60° C. at a speed of 300 r / min for 16 hours to obtain a microcapsule dispersion.

[0079] 8) The microcapsule dispersion was filtered, and then the filter cake was washed three times with anhydrous ethanol and dried by air at 55° C. for 10 h to obtain the composite lubricant.

[0080] Example 6

[0081] In step 1), a 1% chitosan solution is prepared;

[0082] In step 2), a 1% sodium alginate solution was prepared.

[0083] The rest is the same as Example 4.

[0084] Example 7

[0085] In step 1), a 4.5% chitosan solution is prepared;

[0086] In step 2), a 4.5% sodium alginate solution was prepared.

[0087] In step 3), the amount of 3# white oil is adjusted to 3g;

[0088] The rest is the same as Example 4.

[0089] Example 8

[0090] In step 1), a 5% chitosan solution is prepared;

[0091] In step 2), a 5% sodium alginate solution is prepared.

[0092] In step 3), the amount of 3# white oil is adjusted to 2.5 g;

[0093] The rest is the same as Example 4.

[0094] Example 9

[0095] In step 3), 3# white oil was replaced with biodiesel (purchased from Shandong Tonglan Chemical Co., Ltd.).

[0096] The rest is the same as Example 4.

[0097] Example 10

[0098] In step 3), 3# white oil was replaced by polyether polyol SYP-2 (Shandong Deshunyuan Petroleum Technology Co., Ltd.).

[0099] The rest is the same as Example 4.

[0100] Embodiment 11

[0101] In step 3), sodium dodecylbenzenesulfonate is replaced by Tween-60.

[0102] The rest is the same as Example 4.

[0103] Example 12

[0104] In step 3), sodium dodecylbenzene sulfonate is replaced by OP-10.

[0105] The rest is the same as Example 4.

[0106] Embodiment 13

[0107] In step 3), sodium dodecylbenzene sulfonate is replaced by sodium dodecyl sulfate.

[0108] The rest is the same as Example 4.

[0109] Embodiment 14

[0110] In step 3), sodium dodecylbenzenesulfonate is replaced by hexadecyltrimethylammonium bromide.

[0111] The rest is the same as Example 4.

[0112] Comparative Example 1

[0113] 1) Weigh 3 g of chitosan and add it to 200 mL of deionized water under magnetic stirring, add acetic acid dropwise until the solution becomes transparent, and stir for 10 min to obtain a 1.5% chitosan solution.

[0114] 2) Weigh 3 g of sodium alginate, add it into 200 mL of distilled water at 11000 r / min, and stir for 20 min to obtain a 1.5% sodium alginate solution.

[0115] 3) Weigh 1 g of Span-80 and 1.5 g of Tween-80, mix the two, and stir them at a high speed of 11000 r / min for 10 min using an emulsifying shearing machine, add 4 g of peanut oil, stir at a high speed of 11000 r / min for 5 min, and ultrasonically disperse for 10 min to obtain a core material dispersion.

[0116] 4) The core material dispersion was mixed with the sodium alginate solution, and high-speed shearing was performed at a speed of 11000 r / min for 5 min using an emulsifying shearing machine to obtain an emulsion.

[0117] 5) adding the emulsion dropwise to the chitosan solution stirred at a stirring speed of 3000 r / min, adding 33.33 g of 10 wt % CaCl2 aqueous solution, and continuing stirring for 30 min to obtain a microcapsule emulsion; spray drying the microcapsule emulsion at a feed rate of 200 mL / h, a fan efficiency of 30%, and a temperature of 150° C. to obtain microcapsules.

[0118] Comparative Example 2

[0119] 1) Weigh 6 g of gum arabic and add it to 200 mL of deionized water under magnetic stirring, add acetic acid dropwise until the solution becomes transparent, and stir for 10 min to obtain a 3% gum arabic solution.

[0120] 2) Weigh 6 g of sodium alginate, add it into 200 mL of distilled water at 11000 r / min, and stir for 20 min to obtain a 3% sodium alginate solution.

[0121] 3) Weigh 1 g of Span-80 and 3 g of sodium dodecyl sulfate, mix the two, and stir them at a high speed of 11000 r / min for 10 min using an emulsifying shearing machine, add 4 g of soybean oil, stir at a high speed of 11000 r / min for 5 min, and ultrasonically disperse for 10 min to obtain a core material dispersion.

[0122] 4) The core material dispersion was mixed with the sodium alginate solution, and high-speed shearing was performed at a speed of 11000 r / min for 5 min using an emulsifying shearing machine to obtain an emulsion.

[0123] 5) adding the emulsion dropwise to the gum arabic solution stirred at a stirring speed of 3000 r / min, stirring continuously for 30 min, adding 33.33 g of 10 wt% CaCl2 aqueous solution, stirring continuously for 30 min, to obtain a microcapsule emulsion; spray drying the microcapsule emulsion at a feed rate of 800 mL / h, a fan efficiency of 30%, and a temperature of 200° C. to obtain microcapsules.

[0124] Comparative Example 3

[0125] 1) Weigh 3 g of chitosan and add it to 200 mL of deionized water under magnetic stirring, add acetic acid dropwise until the solution becomes transparent, and stir for 10 min to obtain a 1.5% chitosan solution.

[0126] 2) Weigh 3 g of sodium alginate, add it into 200 mL of distilled water at 11000 r / min, and stir for 20 min to obtain a 1.5% sodium alginate solution.

[0127] 3) Weigh 1 g of Span-80 and 1.5 g of Tween-80, mix the two, and stir them at a high speed of 11000 r / min for 10 min using an emulsifying shearing machine, add 4 g of peanut oil, stir at a high speed of 11000 r / min for 5 min, and ultrasonically disperse for 10 min to obtain a core material dispersion.

[0128] 4) The core material dispersion was mixed with the sodium alginate solution, and high-speed shearing was performed at a speed of 11000 r / min for 5 min using an emulsifying shearing machine to obtain an emulsion.

[0129] 5) adding the emulsion dropwise to the chitosan solution stirred at a stirring speed of 3000 r / min, stirring continuously for 30 min, adding 33.33 g of a 10 wt % CaCl2 aqueous solution, stirring continuously for 30 min, to obtain a primary microcapsule emulsion; spray drying the primary microcapsule emulsion at a feed rate of 300 mL / h, a fan efficiency of 30%, and a temperature of 160° C. to obtain primary microcapsules.

[0130] 6) Weigh 1.0 g of primary microcapsules and add them into a three-necked flask containing 100 mL of ammonia water (aqueous solution with an NH3 content of 25 wt%) and a mixed solution of anhydrous ethanol (including 10 mL of ammonia water and 90 mL of anhydrous ethanol), and reflux at 60° C. for 30 min under mechanical stirring at a speed of 300 r / min to obtain a primary microcapsule dispersion.

[0131] 7) Take 3 mL of TEOS and dissolve it in 10 mL of anhydrous ethanol to obtain an ethanol solution of tetraethyl orthosilicate. Use a rubber-tipped dropper to slowly add the ethanol solution of tetraethyl orthosilicate to the primary microcapsule dispersion at 60° C., stir and react at 60° C. at a speed of 200 r / min for 24 hours to obtain a microcapsule dispersion.

[0132] 8) The microcapsule dispersion was filtered, and then the filter cake was washed three times with anhydrous ethanol and dried by air at 55° C. for 10 h to obtain the composite lubricant.

[0133] Test Example 1

[0134] Microcapsule structural characteristics

[0135] 1) Particle size determination

[0136] The lubricants prepared in Examples 1 to 14 and Comparative Examples 1 to 3 were added to tap water to prepare suspensions with a concentration of 1 wt %. After ultrasonic dispersion for 10 min, the D 50 The results are shown in Table 1.

[0137] 2) Determination of coverage and loading capacity

[0138] Each lubricant prepared in Examples 1 to 14 and Comparative Examples 1 to 3 was averaged into two portions.

[0139] For the first portion, the lubricant was washed with anhydrous ethanol three times, dried at 105°C for 2 h, and weighed to obtain the total mass M1 of the lubricant.

[0140] For the second part, the lubricant was added to anhydrous ethanol and ground into powder, then washed with anhydrous ethanol for 3 times to wash away the core material, filtered to obtain filter residue, placed at 105°C and dried for 2 hours, and weighed to obtain the mass M2 of the lubricant residue.

[0141] The amount of core material added is half of the amount of core material used in step 3) in each embodiment or comparative example, calculated as M3.

[0142] The coverage and loading of the core material are calculated using equations (1) and (2).

[0143] Coverage = (M1-M2) / M3×100% Formula (1)

[0144] Loading capacity = (M1-M2) / M1×100% Formula (2)

[0145] The results of coverage and loading are shown in Table 1.

[0146] Table 1

[0147] Example <![CDATA[D 50 Particle size / μm]]> Coverage rate / % Loading amount / % Example 1 15.65 77.87 58.23 Example 2 16.43 76.68 58.01 Example 3 16.21 77.13 57.34 Example 4 15.46 75.88 57.66 Example 5 16.87 75.64 56.99 Example 6 17.43 74.34 57.01 Example 7 18.27 75.01 56.56 Example 8 17.55 73.99 56.37 Example 9 17.28 74.67 55.01 Example 10 17.91 72.13 53.99 Embodiment 11 18.51 71.99 55.99 Example 12 18.34 72.91 53.78 Embodiment 13 18.98 73.89 52.67 Embodiment 14 19.31 71.23 54.13 Comparative Example 1 12.78 58.90 38.88 Comparative Example 2 11.64 55.29 36.99 Comparative Example 3 15.34 65.71 41.69

[0148] According to Table 1, the D 50 The particle size distribution is in the range of 15 to 20 μm, the coverage rate is above 70%, and the loading amount is above 50%.

[0149] Test Example 2

[0150] Evaluation of extreme pressure lubrication performance

[0151] 16 g of sodium bentonite for drilling fluid (Shandong Huawei Bentonite Co., Ltd.) was added to 400 mL of tap water, stirred at 10,000 r / min for 30 min, and allowed to stand in a sealed container for 24 h to obtain a 4% prehydrated bentonite base slurry (referred to as base slurry).

[0152] To 400 mL of the above-prepared bentonite-based slurry, 12 g of the lubricant prepared in Examples 1 to 14 and Comparative Examples 1 to 3 was added respectively, and the mixture was stirred at 3000 r / min for 20 min to obtain a slurry. The mixture was cured at room temperature for 24 h to obtain a cured slurry. According to standard SY / T6094-94, the extreme pressure lubrication coefficient of the cured slurry was measured using an extreme pressure lubrication instrument (EP-C type), and the extreme pressure lubrication coefficient reduction rate was calculated. The results are shown in Table 2.

[0153] According to the results in Table 2, after the composite lubricants prepared in Examples 1 to 14 of the present invention are added to the base slurry, the extreme pressure lubrication coefficient of the curing slurry is reduced by ≥80%, and the lubrication effect is excellent.

[0154] Table 2

[0155] Test samples Extreme pressure lubrication coefficient Extreme pressure lubrication coefficient reduction rate / % Base slurry 0.55 - Base slurry + Example 1 0.069 87.45 Base slurry + Example 2 0.075 86.36 Base slurry + Example 3 0.081 85.27 Base slurry + Example 4 0.089 83.82 Base slurry + Example 5 0.091 83.45 Base slurry + Example 6 0.086 84.36 Base slurry + Example 7 0.090 83.64 Base slurry + Example 8 0.094 82.91 Base slurry + Example 9 0.095 82.73 Base slurry + Example 10 0.101 81.64 Base slurry + Example 11 0.091 83.45 Base slurry + Example 12 0.106 80.73 Base slurry + Example 13 0.098 82.18 Base slurry + Example 14 0.109 80.18 Base slurry + comparative example 1 0.163 70.36 Base slurry + comparative example 2 0.153 72.18 Base slurry + comparative example 3 0.146 73.45

[0156] Test Example 3

[0157] Temperature resistance evaluation

[0158] Each lubricant prepared in Examples 1 to 14 and Comparative Examples 1 to 3 was equally divided into two portions.

[0159] For the first portion, the lubricant was washed with anhydrous ethanol three times, dried at 105°C for 2 h, and weighed to obtain the total mass M3 of the lubricant.

[0160] For the second portion, add it into tap water, ultrasonically disperse for 10 minutes to obtain a dispersion, heat roll at 160°C for 16 hours, cool naturally, filter, wash with anhydrous ethanol three times, filter again to obtain the washed filter residue, place the washed filter residue at 105°C and dry for 2 hours, weigh to obtain the mass M4 of the lubricant residue.

[0161] The core material loss rate was calculated using formula (3) and the results are shown in Table 3.

[0162] Core material loss rate = (M3-M4) / M3×100% Formula (3)

[0163] Table 3

[0164]

[0165]

[0166] According to the results in Table 3, after the composite lubricant dispersions prepared in Examples 1 to 14 of the present invention were hot-rolled at 160°C for 16 hours, the microcapsule core material loss rate was less than 10%, and the composite lubricant dispersions prepared in Examples 1 to 14 of the present invention had good temperature resistance and could withstand temperatures up to 160°C.

[0167] Test Example 4

[0168] Microcapsule strength test

[0169] A small amount of microcapsule samples of Examples 1 to 14 and Comparative Examples 1 to 3 were taken and fixed on mica sheets with glue. After natural drying, the mica sheets were pasted on round iron sheets with double-sided tape to prepare samples. The elastic modulus of the samples was tested using a scanning probe microscope. The results are shown in Table 4.

[0170] Table 4

[0171] Example Elastic modulus / GPa Example 1 2.97 Example 2 2.88 Example 3 2.86 Example 4 2.87 Example 5 2.77 Example 6 2.75 Example 7 2.69 Example 8 2.72 Example 9 2.66 Example 10 2.71 Embodiment 11 2.69 Example 12 2.61 Embodiment 13 2.51 Embodiment 14 2.56 Comparative Example 1 1.34 Comparative Example 2 1.31 Comparative Example 3 1.96

[0172] According to the results in Table 4, the elastic modulus of the microcapsules of the composite lubricants prepared in Examples 1 to 14 is ≥2.5 GPa, and has good mechanical strength.

[0173] Test Example 5

[0174] Storage stability evaluation

[0175] Each lubricant prepared in Examples 1 to 14 and Comparative Examples 1 to 3 was divided into 6 parts on average.

[0176] For the first portion, the lubricant was washed with anhydrous ethanol three times, dried at 105° C. for 2 h, and weighed to obtain the total mass M5 of the lubricant.

[0177] For the second to sixth portions, they were sealed, dried, protected from light, and stored at rest. After 1 day, 7 days, 15 days, 30 days, and 60 days of storage, they were washed with ethanol three times to remove the core material, filtered to obtain the filter residue, and dried at 105°C for 2 hours. The mass of the lubricant residue M6 was weighed. The core material loss rate was calculated using formula (4), and the results are shown in Table 5.

[0178] Core material loss rate = (M5-M6) / M5×100% Formula (4)

[0179] Table 5

[0180]

[0181]

[0182] According to the results of the analysis table 5, the microcapsule core material loss rate of the composite lubricants prepared in Examples 1 to 14 is less than 5% after storage for 60 days, and the storage stability is much better than that of Comparative Examples 1 to 3. The composition and structure of the composite lubricants prepared in Examples 1 to 14 can effectively improve the storage stability of the lubricant.

Claims

1. A method for preparing a composite lubricant, comprising the following steps: 1) dissolving a positively charged polysaccharide in water to obtain a positively charged polysaccharide aqueous solution; 2) dissolving the negatively charged polysaccharide in water to obtain a negatively charged polysaccharide aqueous solution; 3) mixing the lipophilic emulsifier and the hydrophilic emulsifier to obtain a mixed emulsifier, and mixing the mixed emulsifier with the core material to obtain a core material dispersion; 4) mixing the core material dispersion with the negatively charged polysaccharide aqueous solution, emulsifying, and obtaining an emulsion; 5) adding the emulsion dropwise to the positively charged polysaccharide aqueous solution, then adding calcium chloride aqueous solution, dispersing to obtain a primary microcapsule emulsion, and then drying the primary microcapsule emulsion to obtain primary microcapsules; 6) mixing the primary microcapsules with a mixed solution of aqueous ammonia and ethanol, stirring and condensing and refluxing to obtain a primary microcapsule dispersion; 7) dissolving tetraethyl orthosilicate in anhydrous ethanol to obtain an ethanol solution of tetraethyl orthosilicate, and then dropwise adding the ethanol solution of tetraethyl orthosilicate into the primary microcapsule dispersion to react and obtain a microcapsule dispersion; 8) filtering, washing and drying the microcapsule dispersion to obtain the composite lubricant.

2. The preparation method according to claim 1, characterized in that: The positively charged polysaccharide is chitosan and / or gum arabic; and / or The negatively charged polysaccharide is sodium alginate and / or calcium alginate.

3. The preparation method according to claim 1, characterized in that: The lipophilic emulsifier is Span-80 and / or Span-60; and / or The hydrophilic emulsifier is at least one of Tween-80, Tween-60, OP-10, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and hexadecyltrimethylammonium bromide.

4. The preparation method according to claim 1, characterized in that: The core material is at least one of peanut oil, soybean oil, biodiesel, white oil and polyether polyol.

5. The preparation method according to claim 1, characterized in that: The positively charged polysaccharide is used in an amount of 3 to 6 parts by mass, the negatively charged polysaccharide is used in an amount of 3 to 6 parts by mass, the lipophilic emulsifier is used in an amount of 1 part by mass, the hydrophilic emulsifier is used in an amount of 1.5 to 3 parts by mass, and the core material is used in an amount of 4 to 5 parts by mass.

6. The preparation method according to claim 1, characterized in that: The ratio of the total mass of the positively charged polysaccharide and the negatively charged polysaccharide to the mass of the core material is 0.8:1 to 8:1; preferably, the ratio of the total mass of the positively charged polysaccharide and the negatively charged polysaccharide to the mass of the core material is 1:1 to 6:1; preferably, the ratio of the total mass of the positively charged polysaccharide and the negatively charged polysaccharide to the mass of the core material is 1:1 to 3:1; and / or The mass ratio of the lipophilic emulsifier to the hydrophilic emulsifier is 1:(1-5), preferably 1:(1-3.5), and more preferably 1:(1.5-3).

7. The preparation method according to claim 1, characterized in that: The mass / volume ratio of the primary microcapsules to the tetraethyl orthosilicate is 1 g:(5 to 10 mL), preferably 1 g:(5 to 8 mL).

8. The preparation method according to claim 1, characterized in that: In step 1), the mass content of the positively charged polysaccharide in the positively charged polysaccharide aqueous solution is 1% to 5%, preferably 1.5% to 4.5%, more preferably 1.5% to 3%; and / or In step 2), the mass content of the negatively charged polysaccharide in the negatively charged polysaccharide aqueous solution is 1% to 5%, preferably 1.5% to 4.5%, more preferably 1.5% to 3%; and / or The volume ratio of the tetraethyl orthosilicate to the anhydrous ethanol is (0.5-1):1; and the reaction time is 16 to 24 hours.

9. The preparation method according to claim 1, characterized in that: In step 3), the lipophilic emulsifier and the hydrophilic emulsifier are stirred and dispersed using an emulsifying shearing machine to obtain the mixed emulsifier, and the mixed emulsifier and the core material are stirred and dispersed using an emulsifying shearing machine and then ultrasonically dispersed to obtain the core material dispersion; and / or In step 4), the core material dispersion and the negatively charged polysaccharide aqueous solution are stirred and emulsified using an emulsifying shearing machine to obtain the emulsion.

10. The preparation method according to claim 1, characterized in that: In step 5), the primary microcapsule emulsion is dried using a spray dryer, wherein the inlet air temperature of the spray dryer is 120 to 210° C. and the feed rate is 300 to 500 mL / h; preferably, the inlet air temperature is 150 to 200° C., and more preferably, the inlet air temperature is 160 to 195° C.; and / or In step 6), the stirring and condensation reflux time is 20 to 30 minutes; and / or In step 8), the filtered product is washed with anhydrous ethanol and dried at 55 to 65° C. for 10 to 12 hours.

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