Methods of making pol yurea powders, gels and greases, and related compositions made therefrom
AssigneeNovitas Chem Solutions
InventorLiwen WEI
Life of this patent
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Abstract
A method of making a urea containing powder by injecting an amine and an isocyanate simultaneously into a mixing chamber is disclosed. The method comprises mixing in a high-pressure impingement mixing device at a pressure of at least 2500 psi for a time less than 10 seconds. The resulting urea containing powders have defined particle sizes and molecular weight distributions as well as a stoichiometric mole ratio of isocyanates and amine functionalities. Methods of making a thickened polyurea containing master batch with the urea containing powders using a shear thickening step, and making a grease by gelling the first or second urea containing powder under heat and in the presence of an oil are also disclosed.
Claims29
A method of making a urea containing powder, comprising:
- injecting at least one liquid amine and at least one liquid isocyanate simultaneously into a mixing chamber, said mixture chamber comprising at least one high pressure impingement mixing device;
- mixing the at least one amine and the at least one isocyanate in the at least one high pressure impingement mixing device at a pressure of at least 2500 psi for a time sufficient to form a first urea containing powder with substantially no unreacted isocyanates, said time is less than 10 seconds, wherein the first urea containing powder has an average particle size (D50) represented as D1, and molecular weight distribution (D90-D50) represented as DD1;
- feeding the first urea containing powder into a sizing device to form a second urea containing powder with an average particle size (D50) represented as D2, wherein D2 is less than D1, and molecular weight distribution (D90-D50) represented as DD2, wherein DD2 is less than DD1,
- wherein the second urea containing powder composition has a stoichiometric mole ratio of isocyanates and amine functionalities.
Dependencies are inferred from the claim text.