Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1999-12-10
2001-05-29
Gupta, Yogendra (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S202000, C510S245000, C510S285000, C510S286000, C510S365000, C510S367000, C510S371000, C510S372000, C510S405000, C510S432000, C134S038000
Reexamination Certificate
active
06239090
ABSTRACT:
BACKGROUND OF INVENTION
This invention relates to thickened compositions for paint and coating removal. More particularly, this invention relates to compositions containing alkylene carbonate or dialkyl carbonate or both, hydrogen peroxide, water and a polyvinyl pyrrolidone thickener.
Paint removing compositions are commonly used in industry, such as for stripping paint from airplane fuselages. Conventional paint remover compositions include methylene chloride, phenol, or caustic. Each of these materials, however, has inherent problems during use. While methylene chloride based compositions are very effective as paint removers, methylene chloride is a highly volatile material which is considered toxic. Similarly, phenol is highly toxic. Furthermore, caustic causes bums and attacks aluminum. Due to the deficiencies and disadvantages of conventional paint removing compositions, new paint removing compositions are highly desirable.
In addition, it is frequently desirable to use thickened paint removers. The thickened paint removers serve to allow application of the compositions to slanted surfaces, such as vertical surfaces. It follows that new, thickened paint removing compositions that meet the concerns above would be highly desirable.
SUMMARY OF INVENTION
In one broad respect, this invention is a composition useful as a paint remover, comprising: a carbonate, hydrogen peroxide and water.
In another broad respect, this invention is a process for removing paint, comprising: applying a composition containing a carbonate, hydrogen peroxide, and water to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint.
In another broad respect, this invention is a composition useful as a paint remover, comprising: effective amounts of a carbonate, a thickener, hydrogen peroxide, and water. This composition may optionally contain an alcohol, a polyvinyl pyrrolidone thickener, a glycol ether, an alkylene carbonate, or a combination thereof. By effective amounts, it is meant amounts of each component effective to provide a composition capable of removing at least a portion of the paint from a painted surface. A variety of amounts will be effective in the practice of this invention. Routine experimentation by testing compositions as paint removers is all that is needed to determine effective amounts.
In another broad respect, this invention is a process for removing paint, comprising: applying a composition containing effective amounts of (a) a carbonate, (b) a thickener, (c) hydrogen peroxide and (d) water to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint.
In another broad respect, this invention is a process for removing paint, comprising: applying a composition containing dialkyl carbonate, hydrogen peroxide, and water to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint.
The surfaces to be treated may be sealed with a variety of sealants, such as polysulfide, polyurethane, lacquer, epoxy, and the like. The compositions can be used to remove paints and coatings from furniture, automobiles, boats, trains, airplanes, military vehicles, and so forth.
This invention has a number of advantages. For example, the compositions have several important attributes, including low toxicity, high efficacy in removing paint and coatings, and neutral pH (or slightly acidic or slightly basic pH). Furthermore, in the case of propylene carbonate, the propylene carbonate breaks down into propylene glycol, which is non-toxic. Likewise, hydrogen peroxide decomposes over time to water. Hence, the propylene carbonate compositions of this invention are environmentally friendly, particularly as compared to chlorinated hydrocarbons and the like which are commonly used for paint and coating removing. In addition, the compositions of this invention cause blistering and bubbling in such a short period of time that it is envisioned that the compositions of this invention might be applied in liquid form, as opposed to the gels which are commonly applied which lesson evaporation of the chlorinated hydrocarbons, for example. Moreover, the PVP thickened compositions of this invention are peroxide stable, retain their viscosity over time, and provide clean, miscible, solutions free of phase separation, cloudiness, or flocculation. It was surprisingly found that the PVP thickeners provided superior results compared to many other types of thickeners. In particular, the PVP-thickened compositions were unique in providing clear, stable compositions. Other thickeners such as the polyacrylic acid types formed “clumps” and would not disperse in the formulations. Still others, such as the Klucel® type, have now been found to thicken initially but then decrease in viscosity sharply with time on standing.
It has further been advantageously found that by employing hydrogen peroxide in the form of an at least 50% aqueous solution, a miscible solution forms with alkylene carbonate. In the context of this invention, by miscible solution it is meant a single phase solution. The resulting composition has surprisingly superior paint removing properties, which is believed to be due to the limited amount of water present. The compositions may be blended with additional cosolvents, activators, corrosion inhibitors, and the like, or may be used directly to effect paint removal. The compositions of this invention may advantageously be non-flammable, of low volatility and free of carcinogenic chemicals.
DETAILED DESCRIPTION OF THE INVENTION
The compositions of this invention contain a carbonate, a thickener, hydrogen peroxide, and water.
The hydrogen peroxide and water can be conveniently obtained from commercial sources as aqueous hydrogen peroxide solutions of varying percentages. Hydrogen peroxide is commonly available in aqueous solutions at a concentration of from about 1 to about 80 percent. For example, industrial solutions are often 30 percent or more by weight hydrogen peroxide solutions. It has been found that in the practice of this invention, the use of a 50% aqueous hydrogen peroxide solution is particularly effective. It may be appreciated that highly concentrated hydrogen peroxide should be handled carefully and appropriately since such materials are considered strong oxidizers. It may also be noted that once the concentrated hydrogen peroxide solution is admixed with carbonate, the concentration of hydrogen peroxide decreases which thus reduces the hazardous nature of the final composition. For example, when the overall concentration of hydrogen peroxide in the admixed composition is less than about 30%, special precautions need not be taken to handle the composition. Use of an aqueous hydrogen peroxide solution having a concentration of from about 30% to about 50% is preferred in the practice of this invention. In this regard, it should be appreciated that a lower hydrogen peroxide concentration of the aqueous solution may require use of cosolvents, surfactants, or the like to provide a miscible final composition.
In one embodiment of this invention, the amount of hydrogen peroxide in the total composition is at least 4 percent by weight. In another embodiment, the amount of hydrogen peroxide in the total composition is at least 10 percent by weight. In another embodiment of this invention, the amount of hydrogen peroxide is at least 15 percent by weight of the total composition or, alternatively, at least 35 percent by weight. The composition may be diluted. If diluted, the final peroxide amount is preferably in the range from 3% to 8%.
The organic carbonate used in the practice may be an alkylene carbonate, a dialkyl carbonate, or combination thereof. More than one alkylene or dialkyl carbonate or combination thereof may be employed, such as use of both ethylene and propylene carbonate or ethylene or propylene carbonate and dimethyl carbonate. It should be appreciated that the aklylene carbonates are cyclic carbonates. In general, the amount of carbonate in the thickened
Baldwin Robert E.
Darragas Katty
Machac, Jr. James R.
Marquis Edward T.
Woodrum Susan Aileen
Boyer Charles
Gupta Yogendra
Huntsman Petrochemical Corporation
O'Keefe Egan & Peterman, LLP
LandOfFree
Thickened paint and coating remover does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thickened paint and coating remover, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thickened paint and coating remover will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2484939