The present invention relates to the field of urea and urethane thickeners based on polyalkoxy amines and alcohols.
The manufacture of grease requires the thickening of a base oil to a viscosity that enables the grease to stay in the bearing or other mechanism that needs to be lubricated by the base oil. The present invention improves the properties of the grease through the use of novel thickeners.
The present invention relates to the field of urea and urethane grease thickeners. The use of ureas and urethanes that increase the viscosity of the base oil results in longer lasting greases than those thickened with carboxylic acid soaps or sulfonate salts and provide better lubricity than those thickened with clays. The present invention results in the ability to make greases with a wider range of viscosities and with greater oxidative stability.
Attention is now directed to the following FIGURES that describe embodiments of the present invention:
Many grease applications are now sealed systems where the grease needs to last the life of the bearing or other mechanism to be lubricated. Lithium salts of carboxylic acids have been used for many years, but as lithium costs have increased due to battery demand, these are no longer viable options. In addition, the lithium and calcium salts of carboxylic acids and sulfonates lack the oxidative stability of ureas.
The present invention is the use of ether amines as thickening agents. The preferred starting materials are from the Proxamine® family of ether amines produced by Crison Chemistry, but more traditional ether amines by Evonik®, trade named Tomamines®, that are produced by reacting acrylonitrile with EXXAL® alcohols and reduced to the primary amine functionality may be used. Additionally, linear alcohols from the dehydration of fatty acids are also suitable starting materials to make the ether amines.
The preferred isocyanate is toluene diisocyanate and its isomers. Toluene diisocyanate is preferred for its electron density and its commercial availability. However, any polyisocyanate is acceptable, such as p-phenylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, Isophrone diisocyanate, methylene diphenyl diisocyanate as well as any other polyisocyanate that results in satisfactory thickening.
To 400 g of Hydrocal 500™ (obtained from Calumet Specialty Products) was added 493 g of Proxamine® nB51 (obtained from Crison Chemistry). To this mixture added 104 g of toluene diisocyanate was added over 10 minutes and the mixture increased in viscosity substantially and exothermed to 75 C. The temperature was raised slowly to 165 C and held for 4 hours. After cooling to ambient temperature, the result was a base grease of high viscosity and smooth consistency.
This application is related to, and claims priority from, U.S. Provisional Patent application No. 63/449,346 filed Mar. 2, 2023. Application No. 63/449,346 is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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63449346 | Mar 2023 | US |