A polyurethane type water-based lubricating additive and its preparation method and application

Abstract

The invention provides a polyurethane type water-based lubricating additive and a preparation method and application thereof, belonging to the field of lubrication technology. The molecular chain of the polyurethane type water-based lubricating additive of the invention contains a water-soluble polyether side chain and a carboxylate radical, and the paired ion of the carboxylate radical is a diquaternary ammonium salt cation. The carboxylate radical is conducive to the lubricating additive to form adsorption on the surface of a metal substrate with a positive charge through electrostatic action, and the hydrophobic unit from isocyanate is conducive to the lubricating additive to form adsorption on the surface of a weakly polar hydrophobic substrate, so that the water-based lubricant is suitable for a variety of hydrophilic and hydrophobic friction pairs. At the same time, the polyether segment can improve the water solubility of the lubricating additive, and the diquaternary ammonium salt cation not only provides antibacterial performance, but also a diquaternary ammonium salt molecule can form a dynamic crosslinking point with two carboxylates on the polyurethane molecular chain through electrostatic action, further improving its viscosity.

Description

Technical Field

[0001] The invention relates to the technical field of lubrication, and in particular to a polyurethane type water-based lubricating additive and a preparation method and application thereof. Background Art

[0002] Compared with traditional oil-based lubricants, water as a lubricant has many obvious advantages. Water-based lubricants are non-flammable and therefore safer to use; water has a high specific heat capacity and therefore has good cooling properties; and water-based lubricants are also environmentally friendly. Therefore, water-based lubricating materials have become one of the important branches in the field of lubrication technology, and the study of high-performance water-based lubricants has important practical significance in the fields of mechanical processing and biolubrication.

[0003] The existing water-based lubricants mainly include nitrogen, sulfur, phosphorus and boron additives and water-soluble organic metal additives, and most of them are small molecule additives. For example, Chinese invention patent CN 113816915A discloses a small molecule type ionic liquid water-based lubricant additive, which has good friction reduction and anti-wear effects. However, small molecule lubricant additives still have the problems of low viscosity and biotoxicity risks, and often do not have the versatility for a variety of friction pairs, which greatly limits their application in water-based lubricants. Summary of the invention

[0004] The purpose of the present invention is to provide a polyurethane type water-based lubricating additive and a preparation method and application thereof. The polyurethane type water-based lubricating additive is suitable for lubrication between friction pairs of various materials; it can effectively improve the lubrication performance and service life of water-based lubricating products and has high viscosity.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a polyurethane type water-based lubricating additive, which contains a water-soluble polyether side chain and a carboxylate radical, wherein the carboxylate radical is paired with a diquaternary ammonium salt cation, and the polyurethane type water-based lubricating additive has a structure shown in Formula I:

[0007]

[0008] In Formula I, R 1 Hexamethylene or

[0009] R 2 is methyl or ethyl, R 3 is H or methyl;

[0010] a=20~100 and a is an integer, b=20~100 and b is an integer, a:b=1:(1~2), c=3~46 and c is an integer; d is 2, 3, 4 or 5.

[0011] The present invention provides a method for preparing the polyurethane type water-based lubricating additive described in the above technical solution, comprising the following steps:

[0012] Mixing diisocyanate, carboxyl diol, catalyst and first solvent to carry out addition-polymerization reaction to obtain a polymer product;

[0013] The polymerized product, monomethylol polyether and a condensation agent are mixed to carry out a condensation reaction to obtain a polyurethane containing a carboxylate group and a polyether side chain;

[0014] The dibromoalkane, triethylamine and a second solvent are mixed to undergo a nucleophilic substitution reaction to obtain a diquaternary ammonium salt molecule;

[0015] The polyurethane containing carboxylate radicals and polyether side chains, the diquaternary ammonium salt molecules and water are mixed to perform ion exchange to obtain a polyurethane type water-based lubricating additive;

[0016] The diisocyanate is hexamethylene diisocyanate or isophorone diisocyanate;

[0017] The carboxyl diol is dimethylol propionic acid or dimethylol butyric acid;

[0018] The monomethylol polyether is one of polyethylene glycol monomethyl ether with a molecular weight of 200-2000 and polypropylene glycol monomethyl ether with a molecular weight of 200-400.

[0019] Preferably, the molar ratio of the diisocyanate to the carboxyl diol is (1.1-1.2):1.

[0020] Preferably, the catalyst includes stannous octoate, dibutyltin dilaurate or bismuth neodecanoate; the condensing agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 1-hydroxybenzotriazole; the temperature of the addition-polymerization reaction is 70-80°C and the time is 4-8h.

[0021] Preferably, the molar ratio of the monomethylol polyether to the carboxyl diol unit in the polymerization product is (0.5-1.0):1, the molar ratio of the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide to the carboxyl diol unit in the polymerization product is 1:1; and the molar ratio of the 1-hydroxybenzotriazole to the carboxyl diol unit in the polymerization product is 1:1.

[0022] Preferably, the condensation reaction temperature is 20-30° C. and the reaction time is 24 h.

[0023] Preferably, the dibromoalkane is 1,4-dibromobutane, 1,6-dibromohexane, 1,8-dibromooctane or 1,10-dibromodecane.

[0024] Preferably, the molar ratio of the dibromoalkane to triethylamine is 1:(3-6); the temperature of the nucleophilic substitution reaction is 70-80° C., and the time is 24 hours.

[0025] Preferably, the mass ratio of the polyurethane containing carboxylate groups and polyether side chains to the diquaternary ammonium salt molecules is 1:(2-6); the temperature of the ion exchange is 20-30° C., and the time is 24-72 hours.

[0026] The present invention provides the use of the polyurethane type water-based lubricating additive described in the above technical solution or the polyurethane type water-based lubricating additive prepared by the preparation method described in the above technical solution in the field of biomedicine or mechanical processing.

[0027] The invention provides a polyurethane type water-based lubricating additive, wherein the molecular chain of the polyurethane type water-based lubricating additive contains a water-soluble polyether side chain and a carboxylate radical, and the paired ion of the carboxylate radical is a diquaternary ammonium salt cation. The carboxylate radical is conducive to the lubricating additive to form adsorption on the surface of a metal substrate with a positive charge through electrostatic action, and the hydrophobic unit from isocyanate is conducive to the lubricating additive to form adsorption on the surface of a weakly polar hydrophobic substrate, thereby making the water-based lubricant suitable for a variety of hydrophilic and hydrophobic friction pairs. At the same time, the polyether segment can improve the water solubility of the lubricating additive, and the diquaternary ammonium salt cation not only provides antibacterial performance, but also a diquaternary ammonium salt molecule can form a dynamic crosslinking point with two carboxyl radicals on a polyurethane molecular chain (there are multiple carboxyl groups on the polyurethane molecular chain (a segment), and a diquaternary ammonium salt molecule contains two cations, which can simultaneously generate electrostatic action with two carboxyl groups) through electrostatic action, thereby further improving its viscosity.

[0028] The water-based lubricating additive of the present invention is added to water at a low dose (2wt%), which can effectively reduce the friction coefficient of water and is suitable for lubrication between friction pairs of various materials; at the same time, the lubricating additive can effectively inhibit the growth of microorganisms, which is beneficial to improving the storage and service life of water-based lubricants, and is expected to be used in the fields of biomedical lubrication and mechanical processing.

[0029] The present invention utilizes the polyurethane molecular chain composition and structural design to achieve the versatility of water-based lubricants on different friction pairs, so that the water-based lubricants have good lubrication properties on hydrophilic or hydrophobic substrate surfaces such as polymers, metals and ceramics, while effectively solving the problem of water-based lubricants being prone to bacterial growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the H NMR spectrum of the polyurethane lubricating additive prepared in Example 1;

[0031] Figure 2 This is the H NMR spectrum of the polyurethane lubricating additive prepared in Example 2;

[0032] Figure 3 Infrared spectrum of the polyurethane lubricating additive prepared in Example 3

[0033] Figure 4 This is a graph showing the effect of the polyurethane lubricating additive prepared in Example 2 on the viscosity of water;

[0034] Figure 5 This is a graph showing the antibacterial performance of the polyurethane lubricating additive prepared in Example 2. DETAILED DESCRIPTION

[0035] The present invention provides a polyurethane type water-based lubricating additive, which contains a water-soluble polyether side chain and a carboxylate radical, wherein the carboxylate radical is paired with a diquaternary ammonium salt cation, and the polyurethane type water-based lubricating additive has a structure shown in Formula I:

[0036]

[0037] In Formula I, R 1 Hexamethylene or

[0038] R 2 is methyl or ethyl, R 3 is H or methyl;

[0039] a=20~100 and a is an integer, b=20~100 and b is an integer, a:b=1:(1~2), c=3~46 and c is an integer; d is 2, 3, 4 or 5.

[0040] In the present invention, the polyurethane water-based lubricating additive is preferably:

[0041]

[0042] (a=20~40, b=30~50, c=7),

[0043]

[0044] (a=20-40, b=30-50, c=42) or

[0045]

[0046] (a=20~40, b=30~50, c=6).

[0047] The present invention provides a method for preparing the polyurethane type water-based lubricating additive described in the above technical solution, comprising the following steps:

[0048] Mixing diisocyanate, carboxyl diol, catalyst and first solvent to carry out addition-polymerization reaction to obtain a polymer product;

[0049] The polymerized product, monomethylol polyether and a condensation agent are mixed to carry out a condensation reaction to obtain a polyurethane containing a carboxylate group and a polyether side chain;

[0050] The dibromoalkane, triethylamine and a second solvent are mixed to undergo a nucleophilic substitution reaction to obtain a diquaternary ammonium salt molecule;

[0051] The polyurethane containing carboxylate radicals and polyether side chains, the diquaternary ammonium salt molecules and water are mixed to perform ion exchange to obtain a polyurethane type water-based lubricating additive;

[0052] The diisocyanate is hexamethylene diisocyanate or isophorone diisocyanate;

[0053] The carboxyl diol is dimethylol propionic acid or dimethylol butyric acid;

[0054] The monomethylol polyether is one of polyethylene glycol monomethyl ether with a molecular weight of 200-2000 and polypropylene glycol monomethyl ether with a molecular weight of 200-400.

[0055] In the present invention, unless otherwise specified, the required raw materials for preparation are all commercially available products well known to those skilled in the art.

[0056] The invention mixes diisocyanate, carboxyl diol, a catalyst and a first solvent, and performs addition-polymerization reaction to obtain a polymerization product.

[0057] In the present invention, the diisocyanate is hexamethylene diisocyanate or isophorone diisocyanate.

[0058] In the present invention, the carboxyl diol is dimethylol propionic acid or dimethylol butyric acid.

[0059] In the present invention, the molar ratio of the diisocyanate to the carboxyl diol is preferably (1.1-1.2):1, more preferably 1.1:1.

[0060] In the present invention, the catalyst preferably includes stannous octoate, dibutyltin dilaurate or bismuth neodecanoate; the mass of the catalyst is preferably 0.1-1.0% of the total mass of the carboxyl diol and the diisocyanate, more preferably 0.47-0.6%, and further preferably 0.47-0.53%.

[0061] In the present invention, the first solvent preferably includes dioxane, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone; the present invention has no special limitation on the amount of the first solvent, which can be adjusted according to actual needs to ensure smooth reaction.

[0062] In the present invention, the process of mixing the diisocyanate, carboxyl diol, catalyst and the first solvent is preferably to dissolve the diisocyanate and carboxyl diol in the first solvent and then add the catalyst.

[0063] In the present invention, the temperature of the addition-polymerization reaction is preferably 70-80° C., the time is preferably 4-8 hours, and more preferably 6 hours; during the addition-polymerization reaction, diisocyanate and carboxyl diol generate polyurethane through stepwise addition polymerization.

[0064] After the addition-polymerization reaction is completed, the present invention preferably cools the obtained product to room temperature to obtain a polymerized product.

[0065] After obtaining the polymerization product, the present invention mixes the polymerization product, monomethylol polyether and a condensation agent to carry out a condensation reaction to obtain a polyurethane containing a carboxylate group and a polyether side chain.

[0066] In the present invention, the monomethylol polyether is one of polyethylene glycol monomethyl ether with a molecular weight of 200-2000 and polypropylene glycol monomethyl ether with a molecular weight of 200-400, and the molecular weight of the polyethylene glycol monomethyl ether is more preferably 350-1900.

[0067] In the present invention, the condensing agent is preferably 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and 1-hydroxybenzotriazole (HOBT).

[0068] In the present invention, the molar ratio of the monomethylol polyether to the carboxyl diol unit in the polymerization product is preferably (0.5-1.0):1, more preferably 1:1, the molar ratio of the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide to the carboxyl diol unit in the polymerization product is preferably 1:1; the molar ratio of the 1-hydroxybenzotriazole to the carboxyl diol unit in the polymerization product is preferably 1:1.

[0069] The present invention has no special limitation on the mixing of the polymerization product, monomethylol polyether and condensation agent, and the materials can be uniformly mixed according to a process well known in the art.

[0070] In the present invention, the temperature of the condensation reaction is preferably 20-30° C., and the time is preferably 24 hours. During the condensation reaction, the hydroxyl groups of the monomethylol polyether react with part of the carboxyl groups on the polyurethane to form a polyurethane containing carboxylate groups and polyether side chains.

[0071] After the condensation reaction is completed, the product is preferably dialyzed and freeze-dried in sequence to obtain a polyurethane containing carboxylate groups and polyether side chains. The dialysis and freeze-drying are not particularly limited in the present invention and can be carried out according to processes well known in the art.

[0072] The invention mixes dibromoalkane, triethylamine and a second solvent, and performs a nucleophilic substitution reaction to obtain a diquaternary ammonium salt molecule.

[0073] In the present invention, the dibromoalkane is preferably 1,4-dibromobutane, 1,6-dibromohexane, 1,8-dibromooctane or 1,10-dibromodecane.

[0074] In the present invention, the molar ratio of the dibromoalkane to triethylamine is preferably 1:(3-6), more preferably 1:6.

[0075] In the present invention, the second solvent is preferably ethanol or acetonitrile.

[0076] The present invention has no special limitation on the mixing of the dibromoalkane, triethylamine and the second solvent, and the materials can be uniformly mixed in a manner well known in the art.

[0077] In the present invention, the temperature of the nucleophilic substitution reaction is preferably 70-80° C., and the time is preferably 24 h; the nucleophilic substitution reaction is preferably carried out under condensation reflux conditions.

[0078] After the nucleophilic substitution reaction is completed, the present invention preferably performs rotary evaporation on the obtained product to obtain a diquaternary ammonium salt molecule.

[0079] After obtaining the polyurethane containing carboxyl groups and polyether side chains and the diquaternary ammonium salt molecules, the present invention mixes the polyurethane containing carboxyl groups and polyether side chains and the diquaternary ammonium salt molecules with water and performs ion exchange to obtain the polyurethane type water-based lubricating additive.

[0080] In the present invention, the mass ratio of the polyurethane containing carboxylate groups and polyether side chains to the diquaternary ammonium salt molecules is preferably 1:(2-6), more preferably 1:3.

[0081] The present invention has no special limitation on the mixing of the polyurethane containing carboxylate radicals and polyether side chains, the diquaternary ammonium salt molecules and water, and they can be fully dissolved according to the process well known in the art.

[0082] In the present invention, the temperature of the ion exchange is preferably 20-30°C, the time is preferably 24-72h, more preferably 48h; the pH value is preferably 8; the ion exchange is preferably performed by dialysis; the present invention preferably uses 0.01 mol / L sodium hydroxide aqueous solution to adjust the pH value.

[0083] After the ion exchange is completed, the present invention preferably freeze-dries the obtained product to obtain a polyurethane type water-based lubricating additive. The present invention has no special limitation on the freeze-drying, and it can be carried out according to a process well known in the art.

[0084] The present invention provides the use of the polyurethane type water-based lubricating additive described in the above technical solution or the polyurethane type water-based lubricating additive prepared by the preparation method described in the above technical solution in the field of biomedicine or mechanical processing. The present invention has no special limitation on the application, and the application can be carried out according to methods well known in the art.

[0085] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0086] Example 1

[0087] 18.5 g (0.11 mol) of hexamethylene diisocyanate and 13.4 g (0.10 mol) of dimethylol propionic acid were dissolved in 100 mL of N,N-dimethylformamide, and 0.15 g of dibutyltin dilaurate was added to react at 80°C for 6 h; after cooling to room temperature, 35 g (0.10 mol) of polyethylene glycol monomethyl ether with a molecular weight of 350, 19.2 g (0.10 mol) of EDC and 13.5 g (0.10 mol) of HOBT were added, and after reacting at room temperature for 24 h, dialyzed and freeze-dried in sequence to obtain polyurethane;

[0088] Weigh 30 g (0.10 mol) of 1,10-dibromodecane and 60.6 g (0.60 mol) of triethylamine and dissolve them in 200 mL of acetonitrile. After condensing and refluxing at 80°C for 24 h, rotary evaporation was performed to obtain a diquaternary ammonium salt.

[0089] 10 g of the polyurethane and 30 g of the diquaternary ammonium salt were dissolved in water, the pH value was adjusted to 8 with a 0.01 mol / L sodium hydroxide aqueous solution, dialyzed at room temperature for 48 hours, and freeze-dried to obtain a polyurethane water-based lubricating additive.

[0090]

[0091] (a=20~40, b=30~50, c=7).

[0092] Example 2

[0093] Weigh 24.4 g (0.11 mol) of isophorone diisocyanate and 13.4 g (0.10 mol) of dimethylol propionic acid and dissolve them in 100 mL of N,N-dimethylformamide, add 0.2 g of bismuth neodecanoate and react at 80° C. for 8 h; after cooling to room temperature, add 190 g (0.10 mol) of polyethylene glycol monomethyl ether with a molecular weight of 1900, 19.2 g (0.10 mol) of EDC and 13.5 g (0.10 mol) of HOBT, react at room temperature for 24 h, and then perform dialysis and freeze-drying in sequence to obtain a polyurethane;

[0094] Weigh 27.2 g (0.10 mol) of 1,8-dibromooctane and 60.6 g (0.60 mol) of triethylamine and dissolve them in 200 mL of acetonitrile. After condensing and refluxing at 80°C for 24 h, rotary evaporation was performed to obtain a diquaternary ammonium salt.

[0095] Dissolve 10 g of the polyurethane and 30 g of the diquaternary ammonium salt in water, adjust the pH value to 8 with 0.01 mol / L sodium hydroxide solution, dialyze for 48 hours, and freeze-dry to obtain a polyurethane lubricating additive with the structural formula:

[0096]

[0097] (a=20~40, b=30~50, c=42).

[0098] Example 3

[0099] Weigh 18.5 g (0.11 mol) of hexamethylene diisocyanate and 13.4 g (0.10 mol) of dimethylol propionic acid and dissolve them in 100 mL of N,N-dimethylformamide, add 0.2 g of dibutyltin dilaurate and react at 80°C for 6 h; after cooling to room temperature, add 40 g (0.10 mol) of polypropylene glycol monomethyl ether with a molecular weight of 400, 19.2 g (0.10 mol) of EDC and 13.5 g (0.10 mol) of HOBT, react at room temperature for 24 h, perform dialysis and freeze-drying in sequence to obtain polyurethane;

[0100] Weigh 27.2 g (0.10 mol) of 1,8-dibromooctane and 60.6 g (0.60 mol) of triethylamine and dissolve them in 200 mL of acetonitrile. Condensate and reflux at 80°C for 24 h, and then rotary evaporate to obtain a diquaternary ammonium salt.

[0101] 10 g of the polyurethane and 30 g of the diquaternary ammonium salt were dissolved in water, the pH value was adjusted to 8 with a 0.01 mol / L sodium hydroxide solution, and the mixture was dialyzed for 48 hours and freeze-dried to obtain a polyurethane lubricating additive.

[0102]

[0103] (a=20~40, b=30~50, c=6).

[0104] Characterization and performance testing

[0105] 1) Figure 1 The NMR hydrogen spectrum of the polyurethane lubricating additive prepared in Example 1; Figure 1 As shown in Figure 2, the characteristic chemical shifts of the isocyanate unit (A, B, C), the characteristic chemical shifts of the carboxylic acid diol unit (D, E), and the characteristic chemical shift of the polyethylene glycol segment (F) in the polyurethane structure all appear in Figure 1 At the same time, the characteristic chemical shifts (G, H) of the diquaternary ammonium salt also exist in the NMR spectrum, proving that the lubricating additive of Example 1 was successfully synthesized.

[0106] 2) Figure 2 The NMR hydrogen spectrum of the polyurethane lubricating additive prepared in Example 2; Figure 2 As shown in Figure 2, the characteristic chemical shifts of the isophorone diisocyanate unit (A, B, C, D, E, F, G), the carboxylic acid diol unit (H, I), and the polyethylene glycol segment (J) in the polyurethane structure all appear in Figure 1 At the same time, the characteristic chemical shifts (L, M) of the quaternary ammonium salt also appear in the NMR spectrum, proving that the lubricating additive of Example 2 was successfully synthesized.

[0107] 3) Figure 3 The infrared spectrum of the polyurethane lubricating additive prepared in Example 3; Figure 3 As shown in Figure 2, the characteristic peak of the carbonyl group in the polyurethane structure appears at 1700 cm -1 The characteristic peak of the polyether segment COC appears at 1110 cm -1 The characteristic peaks of methylene from isocyanate unit and quaternary ammonium salt unit appear at 2934 cm -1 The characteristic peaks of methyl groups from quaternary ammonium salt and polyether chain segments appear at 2975 cm -1 The characteristic peak of the methine from the polyether segment appears at 2863 cm -1 , proving that the lubricating additive of Example 3 was successfully synthesized.

[0108] 4) Lubrication performance test: The lubricating additive prepared in Examples 1 to 3 was added to deionized water at a mass fraction of 2% to prepare a water-based lubricant. Using a CSM friction tester, a spherical material was selected for the upper friction pair and a flat material was selected for the lower friction pair. The lubricant was dripped between the two friction pairs in contact with each other, and a friction test was performed at a load of 1N and a frequency of 1Hz to obtain the friction coefficient. The results are shown in Tables 1 to 2.

[0109] Table 1 Effect of polyurethane lubricating additives on friction coefficients between different friction pairs in Example 1

[0110]

[0111]

[0112] It can be seen from Table 1 that the polyurethane lubricating additive provided by the present invention can significantly reduce the friction coefficient between friction pairs made of various materials.

[0113] Table 2 Effect of the polyurethane lubricating additives prepared in Examples 1 to 3 on the friction coefficient between polydimethylsiloxane and titanium alloy (friction conditions: polyurethane lubricating additive mass fraction 2%, load 1N, frequency 1Hz)

[0114] name Friction coefficient Deionized water 1.70 Deionized water + 2% additives of Example 1 0.60 Deionized water + 2% Example 2 additive 1.20 Deionized water + 2% Example 3 additive 0.70

[0115] It can be seen from Table 2 that the polyurethane lubricating additives of Examples 1, 2 and 3 are all beneficial to reducing the friction coefficient between polydimethylsiloxane and titanium alloy.

[0116] 5) Viscosity: The lubricating additive prepared in Example 2 was added to deionized water at a mass fraction of 2% to prepare a water-based lubricant. The viscosity curve was obtained by changing the shear rate using a rheometer. The results are shown in Figure 4 . Figure 4 The effect of the polyurethane lubricating additive prepared in Example 2 on the water viscosity is shown in FIG. Figure 4 It can be seen that the polyurethane-based lubricating additive can significantly increase the viscosity of water.

[0117] 6) Antibacterial performance: Escherichia coli and Staphylococcus aureus were cultured in liquid culture medium for 10 6 The polyurethane lubricating additive prepared in Example 2 was added to physiological saline at a mass fraction of 2% to prepare a water-based lubricant. The bacteria separated by centrifugation were added to a water-based lubricant to prepare 10 6 The bacterial suspension was diluted 1000 times with saline and 200 μL was plated on solid culture medium. After 24 hours of culture, photos were taken and recorded. The results are shown in Figure 5 .

[0118] Figure 5 This is a graph showing the antibacterial performance of the polyurethane lubricating additive prepared in Example 2. Figure 5 The results showed that the bacteria could not continue to grow after being treated with a lubricant containing 2% of the polyurethane lubricant additive by mass, thus proving that the polyurethane lubricant additive has a good antibacterial effect.

[0119] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A polyurethane type water-based lubricating additive, characterized in that: Containing a water-soluble polyether side chain and a carboxylate radical, wherein the carboxylate radical is paired with a diquaternary ammonium salt cation, the polyurethane type water-based lubricating additive has a structure shown in Formula I: In formula I, R1 is hexamethylene or R2 is methyl or ethyl, R3 is H or methyl; a=20~100 and a is an integer, b=20~100 and b is an integer, a:b=1:(1~2), c=3~46 and c is an integer; d is 2, 3, 4 or 5.

2. The method for preparing the polyurethane type water-based lubricating additive according to claim 1, characterized in that: The following steps are involved: Mixing diisocyanate, carboxyl diol, catalyst and first solvent to carry out addition-polymerization reaction to obtain a polymer product; The polymerized product, monomethylol polyether and a condensation agent are mixed to carry out a condensation reaction to obtain a polyurethane containing a carboxylate group and a polyether side chain; The dibromoalkane, triethylamine and a second solvent are mixed to undergo a nucleophilic substitution reaction to obtain a diquaternary ammonium salt molecule; The polyurethane containing carboxylate radicals and polyether side chains, the diquaternary ammonium salt molecules and water are mixed to perform ion exchange to obtain a polyurethane type water-based lubricating additive; The diisocyanate is hexamethylene diisocyanate or isophorone diisocyanate; The carboxyl diol is dimethylol propionic acid or dimethylol butyric acid; The monomethylol polyether is one of polyethylene glycol monomethyl ether with a molecular weight of 200-2000 and polypropylene glycol monomethyl ether with a molecular weight of 200-400.

3. The preparation method according to claim 2, characterized in that: The molar ratio of the diisocyanate to the carboxyl diol is (1.1-1.2):

1.

4. The preparation method according to claim 2 or 3, characterized in that: The catalyst includes stannous octoate, dibutyltin dilaurate or bismuth neodecanoate; the condensation agent includes 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 1-hydroxybenzotriazole; the temperature of the addition-polymerization reaction is 70-80°C and the time is 4-8h.

5. The preparation method according to claim 4, characterized in that: The molar ratio of the monomethylol polyether to the carboxyl diol unit in the polymerization product is (0.5-1.0):1, the molar ratio of the 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide to the carboxyl diol unit in the polymerization product is 1:1; and the molar ratio of the 1-hydroxybenzotriazole to the carboxyl diol unit in the polymerization product is 1:

1.

6. The preparation method according to claim 2 or 5, characterized in that: The temperature of the condensation reaction is 20-30° C. and the time is 24 hours.

7. The preparation method according to claim 2, characterized in that: The dibromoalkane is 1,4-dibromobutane, 1,6-dibromohexane, 1,8-dibromooctane or 1,10-dibromodecane.

8. The preparation method according to claim 2 or 7, characterized in that: The molar ratio of the dibromoalkane to triethylamine is 1:(3-6); the temperature of the nucleophilic substitution reaction is 70-80° C., and the time is 24 hours.

9. The preparation method according to claim 2, characterized in that: The mass ratio of the polyurethane containing carboxylate radicals and polyether side chains to the diquaternary ammonium salt molecules is 1:(2-6); the temperature of the ion exchange is 20-30° C., and the time is 24-72 hours.

10. Use of the polyurethane type water-based lubricating additive according to claim 1 or the polyurethane type water-based lubricating additive prepared by the preparation method according to any one of claims 2 to 9 in the fields of biomedicine or mechanical processing.

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