Etching a substrate: processes – Forming or treating an ornamented article – Treating glass
Reexamination Certificate
1999-01-21
2002-01-08
Hiteshew, Felisa (Department: 1765)
Etching a substrate: processes
Forming or treating an ornamented article
Treating glass
C427S266000, C427S386000, C252S079400, C216S031000, C216S096000, C216S108000, C216S109000
Reexamination Certificate
active
06337029
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to compositions and methods for chemically etching glass, ceramic and porcelain surfaces.
BACKGROUND OF THE INVENTION
The ability to paint glass, ceramic and porcelain surfaces can offer significant cost savings compared to replacing the substrates. Most air-dry, ambient cured coatings and paints do not bond well to ceramic surfaces without some kind of surface treatment and preparation to improve adhesion. Roughening or increasing the surface area has been found to improve adhesion and can be accomplished by any number of methods including mechanical abrasion.
Mechanical abrasion or sanding is a common method in use for preparing ceramic surfaces for refinishing. However, the labor and time required to prepare large surfaces for painting make this method cost prohibitive, especially when ceramic tile in an entire building requires refinishing.
SUMMARY OF THE INVENTION
The invention relates to a composition for roughening glass, ceramic and porcelain surfaces that is economical, easily applied, safe to use and can be used repeatedly in preparation for refinishing. This invention is also more advantageous than using free hydrofluoric acid because it can be used on large surface areas such as exterior porcelainized steel building panels as well as in enclosed areas with poor ventilation such as on tile and porcelain in bathrooms and kitchens for tubs, sinks and showers. The inventive composition can be applied by those methods known to those skilled in the art. Methods of application include, but are not limited to, application by trowel, brush, spray, or roller.
In general, the composition comprises:
a. bifluoride salts in an amount ranging from 10.0 to 85.0 parts by weight;
b. thickener in an amount ranging from 0.1 to 5.0 parts by weight.
c. organic solvent in an amount ranging from 2.0 to 20.0 parts by weight; and
d. water in an amount ranging from 7.0 to 75.0 parts by weight.
A preservative may be optionally added, the amount of preservative ranging from 0.05 to 0.75 parts by weight.
A surfactant may be optionally added, the amount of surfactant ranging from 0.1 to 2.0 parts by weight.
A toner may be optionally added, the amount of toner ranging from 0.01 to 1.0 parts by weight.
In particular, the invention is directed to a composition having a pH of at least 5.0. The composition has a viscosity in the range of from about 80 to about 100 Krebs Units at 25° C. and has a cream-like consistency. The composition includes the following:
a. bifluoride salts in an amount ranging from 10.0 to 85.0 parts by weight based upon the total weight of the composition, preferred bifluoride salts being selected from the group consisting of sodium bifluoride and ammonium bifluoride;
b. thickener in an amount ranging from 0.1 to 5.0 parts by weight based upon the total weight of the composition, preferred thickeners include polysaccharides, hectorite clays and polyurethanes;
c. organic solvent in an amount ranging from 2.0 to 20.0 parts by weight based upon the total weight of the composition, preferred solvents being propylene glycol and dipropylene glycol; and
d. water in an amount ranging from 7.0 to 75.0 parts by weight based upon the total weight of the composition.
The sum of the weights of the composition preferably totals 100 parts by weight. Of course, other compounds (such as preservative) may be added or omitted from a calculated formulation that has amounts of compounds that total 100 parts by weight, in which case the relative amounts of each of the compounds would be adjusted accordingly to total 100 parts by weight, as would be apparent to one skilled in the art in view of this disclosure.
In a preferred embodiment, a method of preparing glass, ceramic or porcelain surfaces for refinishing large surface areas comprises selecting at least one of the aforementioned substrates and applying a coating having the inventive composition. The surface of the substrate does not need be previously treated so as to be free from surface buildup of grime, soap scum and waxes. The coating preferably has a pH of at least 5.0. The composition has a viscosity preferably in the range from about 80 to about 100 Krebs units at 25° C. and has a cream-like consistency. The coating may be applied by techniques known to those skilled in the art, but is preferably applied by brushing, skim coating or spraying. The inventive coating is left in contact with the substrate for a period of time effective to roughen the surface, preferably for 4 to 5 minutes. The coating is then removed and discarded or more preferably, collected and reused. The inventive compositions are reusable and effective for as many as ten applications. The substrate after treatment will have a roughened surface characterized by improved adhesion of a second coating such as, paints.
The inventive composition is advantageous in that it can be applied to large surface areas easily and rapidly using conventional methods known to those skilled in the art. Buildings that are being rehabbed can have large surface areas that require refinishing in excess of one million square feet. Previous methods of refinishing large surfaces such as the type described include sandblasting or mechanical abrasion. Sandblasting or mechanical abrasion is very time consuming and inefficient. Besides the exorbitant costs of purchasing and maintaining the sandblasting or mechanical abrasion equipment, the equipment used is bulky and difficult to maneuver. Application of a reusable composition for preparing large surfaces for refinishing, such as in buildings undergoing rehabilitation, is believed to be novel and would be extremely efficient and cost effective. The viscous composition is quickly and easily applied to the large surface area for a short duration to roughen the surface and is then removed. The surface is roughened uniformly and without any of the characteristic sand marks observed with mechanical abrasion techniques. Using a composition having a cream-like consistency minimizes any splattering hazards associated with the application. The inventive composition is specially formulated to adhere exceptionally well to vertical surfaces with no run back. Furthermore, the inventive composition can be safely applied in confined areas with poor ventilation.
Other objects and a fuller understanding of the invention will be had from the following description of preferred embodiments.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is directed to a method of using a composition comprising bifluoride salts in a somewhat viscous form for roughening glass, porcelain and/or ceramic surfaces in preparation for refinishing. The invention permits large surface areas to be refinished relatively quickly and economically compared to alternative methods, such as, mechanical abrasion or sanding methods.
The present invention is a composition of bifluoride salts blended and dispersed into a composition having a cream-like consistency for easy application to large surface areas using conventional means such as spraying, brushing, or troweling. This invention uses current paint and coating technology well known in the art to build-in aspects such as brushability, reduced splatter or splashing during application, controlled evaporation of solvents, shelf life stability and improved surface wetting on low surface tension substrates such as glass, glazed ceramics and porcelain. This invention does not include the addition of hydrofluoric acid or other acids to lower the pH of the composition. The pH of the present invention using bifluoride salts are of at least 5. A pH of at least 5 is only mildly acidic and as such is safer to use and handle than hydrofluoric acid.
Krebs type viscometers are widely used to measure the viscosity of paints and is well known to those skilled in the art. The viscosity of the present invention is measured in Krebs units and is preferably from about 80 to about 100 Krebs units at 25° C.
The composition of the present invention comprises bifluoride salts in an amount ranging f
Hardy Richard D.
Jarufe Juan E.
Hiteshew Felisa
Watts, Hoffman, Fisher & Heinke Co. LPA
Xim Products
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