US 4,303,454 AGranted

Vapor stripping process

OwnerRobert C. Petterson, Roger C. Loubierinventors

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Abstract

Protective and residual organic coatings are stripped from a surface by substantially sealing the surface from the atmosphere to provide a stripping zone, forming a stream of gaseous stripping composition in an evaporation zone, contacting the surface with the stripping composition in the gaseous state at about ambient temperature and recirculating the gaseous mixture from the stripping zone to the evaporating zone and back to the stripping zone to rapidly increase the concentration of gaseous stripping composition in the stripping zone. Optionally the surface may be rinsed by raising the temperature of the gaseous stripping composition slightly above ambient temperature, whereby the gaseous stripping composition condenses on the surface and flushes the surface free of adhering particles. This process is useful for objects which can be placed in a stripping zone and substantially sealed from the atmosphere, especially objects having an irregular surface, and also for interior surfaces which can be substantially sealed from the atmosphere, including extensive surfaces such as those of storage tanks, tank cars and the holds and ballast tanks of ships.

Claims13

Dependent claims

In a process of stripping a protective or residual coating from a surface, wherein a gaseous stream of an organic stripping composition normally liquid at ambient temperature and pressure is circulated into contact with the coated surface and wherein neither the coated surface nor the gaseous stream of organic stripping composition is substantially above ambient temperature, the improvement comprising

substantially sealing said coated surface from the atmosphere to form a stripping zone,
forming a gaseous stream of a stripping composition in an evaporation zone containing a body of liquid stripping composition having a vapor pressure of at least 0.2 torr at ambient temperature and pressure, said evaporation zone being connected directly to said stripping zone so as to provide a substantially closed system,
introducing said stream of gaseous stripping composition into said stripping zone into contact with said coated surface and
recirculating the gaseous mixture from said stripping zone to said evaporation zone and then back to said stripping zone to rapidly increase the concentration of said stripping composition in said stripping zone but wherein the gaseous pressure in said stripping zone is not increased above about 200 torr.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 06/165,566Filed 3 Jul 1980 · continuation in part
Priority: 17 Jan 1978
Granted: 1 Dec 1981
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

B05D 3/10
Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate…: by…
B44D 3/16
Accessories or implements for use in connection with painting or artistic drawing, not otherwise provided for ; Methods or devices for colour…:…
C09D 9/005
Chemical paint or ink removers: containing organic solvents
B05D
Processes for applying fluent materials to surfaces, in general

Family

Serial870,103Parent of this continuation-in-part · filed 17 Jan 1978
Serial1,053Parent of this continuation-in-part · filed 4 Jan 1979
US 4,231,804 AParent of this continuation-in-part
US 4,231,805 AParent of this continuation-in-part
US 4,303,454 AThis patent

From the US filing history. Foreign family members aren’t listed.