Coating processes – Removable protective coating applied
Reexamination Certificate
2002-02-22
2004-08-10
Beck, Shrive P. (Department: 1762)
Coating processes
Removable protective coating applied
C427S156000, C427S259000, C427S272000, C427S282000
Reexamination Certificate
active
06773746
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of protective coatings to be used during coating operations of various surfaces including surfaces of vehicles or buildings. More specifically, in one embodiment the invention provides an improved method and composition for masking selected portions of a surface, in particular a vehicle surface, from paint. In another embodiment, this invention provides methods and compositions for protecting the walls and floors of a paint spray booth from paint overspray.
BACKGROUND OF THE INVENTION
It is well known that painting operations often require masking of certain portions of the surface of the painted object to prevent overspray. For example, it is often necessary to mask trim and windows on a vehicle (e.g. a motor vehicle) from paint overspray. Also, building stucco must frequently be protected from paint or primer coats. On occasion, it is necessary to mask painted portions of a vehicle or building from paints of a different color and overspray paints of the same color. In addition, it is often desired to protect the surfaces (e.g. floors or walls) of the area (e.g. paint spray booth) in which the over coating (e.g. painting) operation is performed.
In practice, masking operations are often one of the most time consuming and, therefore, expensive parts of the painting process. In spite of attempts to develop suitable chemical masks for vehicle painting, vehicle painters continue to use primarily masking tape and paper to cover portions of a vehicle where paint is not desired. To mask the trim on a car, for example, will often require many hours of tedious labor. Furthermore, even when done carefully, defects in such paint masks allow paint to contact surfaces that are desired to be protected.
Chemical masking solutions have been proposed to the problem of protecting surfaces during coating processing operations. However, such techniques have often not found extensive use. Some of the proposed chemical masks have been unsuitable for application to portions of a vehicle or building because of damage which would potentially occur to the protected portions of the vehicle or building. Other compositions are not water-soluble which increases the difficulty and expense of removal. In addition, masks that require solvents for removal are problematic in view of the increasing regulation of disposal of solvents as environmental regulation becomes stricter with time. Other compositions are difficult to apply, difficult to remove, excessively costly, or the like.
From the above it is seen that an improved masking that is easily applied and removed, that provides good surface protection, that is economical, and whose use entails little or no environmental impact is needed.
Woodhall et al. has disclosed various masking materials based on dextrin or polyvinyl alcohol. See U.S. Pat. Nos. 5,876,791; 5,362,786; 5,411,760; 5,523,117; 5,302,413 and 5,186,978. See also U.S. Pat. No. 5,550,182 to Ely which discloses a masking material comprising polyvinyl alcohol which is at least 98% hydrolyzed. In addition, in U.S. Pat. Nos. 5,602,992 and 6,117,485 Woodhall et al. disclose masking materials based on dextrin or cellulose derivatives. Such masking materials may include acrylic emulsion polymers as thickeners, however, such emulsion polymers are reported to be alkali-swellable not water soluble.
SUMMARY OF THE INVENTION
The present invention provides a method of temporarily protecting a surface which comprises:
a) applying a continuous coating of a masking material to said surface, which masking material comprises, before drying an aqueous solution or emulsion consisting essentially of a film-forming, carboxylic acid-containing polymer;
b) coating all or a portion of said surface with a coating compound, said masking material preventing said coating compound from contacting said surface; and, thereafter
c) removing said masking material from said surface. The carboxylic acid containing polymer is preferably the sole film-forming component of said solution or emulsion. More preferably said polymer is an acrylic acid or methacrylic acid-containing polymer, e.g. a water soluble acrylic acid or methacrylic acid-containing copolymer.
The method of the invention includes the steps of applying a substantially continuous film of a masking material on a vehicle (e.g. motor vehicle), building, floor, wall (e.g. spray booth floor wall or other spray booth surface) or other surface to be protected during a “coating operation” such as painting. The vehicle, building, or other surface may then be coated with a “coating compound” such as paint or any other compound which is to be applied to the surface. Finally, the masking material may be removed from the surface by washing with water thereby removing any coating compound that may be present on the masking material. These steps may be performed, for example, during an assembly line production of a vehicle or other article of manufacture.
By “coating operation” or “overcoating” it is desired to include any compound which is applied to a surface. Coating compounds include materials such as paint or other finishing materials such as lacquer, varnish, waxes and the like which adhere to the surface to which they are applied thereby forming a relatively permanent finish. Coating compounds, however, may also include compounds designed for temporary application to surfaces as in surface preparative treatments such as acids, oils, and antioxidants from which it may be necessary or desired to shield other surfaces.
By “building” it is intended to mean herein a house, warehouse, apartment, garage, store, or the like. By “vehicle” it is intended to mean herein a car, boat, plane, train, railroad car, or the like. By “substantially continuous film” it is intended to mean herein a film lacking pinholes through which paint or other materials generated during a coating operation processing could reach an underlying surface.
The masking material is, in one embodiment, a composition comprising an aqueous solution consisting essentially of a film-forming acrylic or methacrylic acid copolymer and sufficient alkali to neutralize and solubilize said copolymer in water. The masking materials preferably contain a high concentration of solids. In a particularly preferred embodiment the acrylic or methacrylic acid copolymer may comprise from about 1 percent to about 50 or 60 percent, more preferably from about 1 percent to about 50 percent and most preferably about 2 percent to about 20 percent, e.g. 2 to about 15 percent by weight, of the aqueous solution. A particularly preferred embodiment comprises about 2 to 10 percent, by weight acrylic acid copolymer.
The masking material may additionally include a surfactant. The surfactant may comprise up to about 0.1 weight percent fluorinated surfactant. The surfactant, when present, ranges up to about 5 percent, more preferably up to about 2 percent, and most preferably up to about 1 percent, by weight, of the masking composition. The surfactant may include a foam reduction or foam control agent.
The composition is formulated as an aqueous composition and thus, the remainder of the composition is preferably made up of water. Thus, water may range up to about 98 percent, more preferably up to about 95 percent, by weight, of the composition.
A particularly preferred composition for use in the method of this invention comprises 5%, by weight, of an acrylic or methacrylic acid copolymer and 92 to 94% deionized water. A water soluble alkali, e.g. sodium hydroxide, is added in an amount sufficient to neutralize and solubilize said acrylic or methacrylic acid copolymer, e.g. the pH of the composition may be 7.1 to 7.2 Ethylenediaminetetraaceticacid as an aqueous 0.9% solution, by weight, is added to control spray viscosity, wetting and chelating properties. The final viscosity of the composition is adjusted to 1400-1700 c.p.s. as measured at 25° C., with a Brookfield LFV Viscometer for optimum spray viscosity.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides an improv
BAF Industries
Beck Shrive P.
Fletcher, III William Phillip
Hackler Walter A.
LandOfFree
Method of temporarily protecting a surface by application of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of temporarily protecting a surface by application of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of temporarily protecting a surface by application of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3320864