Exxon Research and Engineering Company

Bernd A Koenitzer

Joseph L Feimer

Robert C Schucker

Christopher J May

A lubricant composition containing both a dialkyl fumarate-vinyl acetate low temperature flow improver and sorbitan fatty acid ester or a polyoxyalkylene sorbitan fatty acid ester has reduced Gel Index.

Reducing low temperature scanning brookfield gel index value in engine

Supported thin film membranes of polyurethane, polyurea/urethane, polyurea/polyurethane alloy blends are prepared by depositing a solution of the appropriate polymer on a microporous hydrophobic support. The solution wets but does not soak through the hydrophobic support because the amounts and ratios of solvents and surfactant used to produce the solution have been adjusted to produce a solution having optimum coating properties (for example, surface tension, solvency, viscosity). The solvent of the solution comprises a mixture of a low surface tension solvent and a high solvency solvent. The polymer solution is optionally aged at least 1 day prior to being coated on the microporous support.

Production of supported thin film membranes

Aromatics are separated from non-aromatics by permeation of the aromatic through a polyurethane-imide membrane. Permeation is conducted under pervaporation, perstraction, reverse osmosis, or dialysis conditions. The membrane is a polyurethane-imide membrane made using polyurethane-imide copolymers which are made by end capping a polyol with a polyisocyanate and then chain extending by reaction with an anhydride.

Polyurethane-imide membranes and their use for the separation of

An anisotropic elastomeric membrane preferably made from polyurea/urethane has been prepared. These anisotropic membranes are made from the corresponding polymeric material by preparing the polymeric material in a good solvent containing less than 5 vol % non-solvent, producing a film of the polymer solution on a support with a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is 1000 mm Hg-min. or less, preferably 200 mm Hg-min or less, most preferably approaching 0 mm Hg-min and quenching the membrane film in a non-solvent yielding a three-layered anisotropic membrane. The preferred anisotropic membranes made from the polyurea/urethane copolymer, useful for the separation of aromatics from mixtures thereof with non-aromatics and saturates, in, for example, a naphtha feed stream, are characterized by possessing a urea index of at least about 20% but less than 100%, an aromatic carbon content of at least about 15 mole percent, a functional group density of at least about 10 per 1000 grams of polymer and a C.dbd.O/NH ratio of less than about 8.0.

Highly aromatic anisotropic polyurea/urethane membranes and their use

An anisotropic elastomeric membrane preferably made from polyurea/urethane has been prepared. These anisotropic membranes are made from the corresponding polymeric material by preparing the polymeric material in a good solvent containing less than 5 vol % non-solvent, producing a film of the polymer solution on a support with a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is 1000 mm Hg-min. or less, preferably 200 mm Hg-min or less, most preferably approaching 0 mm Hg-min and quenching the membrane film in a non-solvent yielding a three-layered anisotropic membrane.

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Clearwater, Canada

Bernd A Koenitzer