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US 5,290,603 AGranted
Method for spraying polymeric compositions with reduced solvent emission and enhanced atomization
AssigneeUnion Carbide Chemicals & Plastics Technology Corporation
InventorsKenneth A. Nielsen, David C. Busby, Marc D. Donohue, Charles W. Glancy
Life of this patent
Estimating the term…
Abstract
Methods are presented by which polymeric compositions, such as coating compositions, can be sprayed with compressed fluids, such as carbon dioxide, nitrous oxide, or ethane, at higher solids levels and with finer atomization to give improved spray application quality with reduced emission of solvent.
Claims20
A process for spraying a polymeric composition to form a spray of finely atomized liquid droplets, which comprises:
- (1) forming a liquid mixture at temperature T.sup.0 in a closed system, said mixture comprising:
- (a) a nonvolatile materials fraction containing at least one polymeric compound and which is capable of being sprayed;
- and
- (b) a solvent fraction which is at least partially miscible wit the nonvolatile materials fraction and contains at least one compressed fluid in an amount which when added to (a) is sufficient:
- (i) to render the viscosity of said mixture to a point suitable for being sprayed;
- and
- (ii) to enable said liquid mixture to form a liquid compressed fluid phase at temperature T.sup.0 ;
- wherein the compressed fluid is a gas at standard conditions of 0.degree. C. and one atmosphere pressure (STP);
- and
- (2) spraying said liquid mixture by passing the mixture at temperature T.sup.0 and spray pressure P.sub.1 into an orifice through which said mixture flows to form a liquid spray, wherein spray pressure P.sub.1 is above the minimum pressure p.sub.2 at which said liquid mixture forms a liquid compressed fluid phase at temperature T.sup.0, thereby passing the liquid mixture through the liquid-liquid region of the polymeric composition and compressed fluid during depressurization.
7 more elements
A process for the spray application of polymeric coating compositions to a substrate, which comprises:
- (1) forming a liquid mixture at temperature T.sup.0 in a closed system, said mixture comprising:
- (a) a nonvolatile materials fraction containing at least one polymeric compound capable of forming a coating on a substrate;
- and
- (b) a solvent fraction which is at least partially miscible with the nonvolatile materials fraction and contains at least one compressed fluid in an amount which when added to (a) is sufficient:
- (i) to render the viscosity of said mixture to a point suitable for being sprayed;
- and
- (ii) to enable said liquid mixture to form a liquid compressed fluid phase at temperature T.sup.0 ;
- wherein the compressed fluid is a gas at standard conditions of 0.degree. C. and one atmosphere pressure (STP);
- and
- (2) spraying said liquid mixture onto a substrate to form a coating thereon by passing the mixture at temperature T.sup.0 and spray pressure P.sub.1 into an orifice through which said mixture flows to form a liquid spray, wherein spray pressure P.sub.1 is above the minimum pressure P.sub.2 at which said liquid mixture forms a liquid compressed fluid phase at temperature T.sup.0, thereby passing the liquid mixture through the liquid-liquid region of the liquid mixture of the polymeric composition and compressed fluid during depressurization.
7 more elements
Dependencies are inferred from the claim text.