Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-08-09
2002-07-16
Gupta, Yogendra N. (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, C510S176000, C510S206000, C510S405000, C510S432000, C510S367000, C134S038000
Reexamination Certificate
active
06420327
ABSTRACT:
TECHNICAL FIELD
This invention relates to coating removers, and, more particularly, to carbonate-based coating removers and methods of using them.
BACKGROUND OF THE INVENTION
Numerous compositions have been developed to remove various coatings, such as paints or varnishes, from a variety of surfaces, including woods and metals. Conventional coating removers typically contain toxic components, such as methylene chloride or phenol, which makes the use of these removers undesirable. However, in recent years, less toxic coating removers have been developed in an effort to replace the more toxic removers. Unfortunately, many of these less toxic coating removers are not nearly as effective as the methylene chloride-based removers. Due to the deficiencies in many of these less toxic coating removers, a need exists for less toxic coating removers that rival the effectiveness of the methylene chloride-based coating removers.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed toward highly effective coating removers that exhibit low toxicity. In one embodiment, the present invention provides for compositions useful as a coating remover. These compositions comprise an alkylene carbonate, hydrogen peroxide, water, a first alcohol, a second alcohol, and, optionally, pine oil.
In another embodiment, the present invention provides for a method of removing a coating from a surface. The method involves applying a composition comprising an alkylene carbonate, hydrogen peroxide, water, a first alcohol, a second alcohol, and, optionally, pine oil to a coated surface, and allowing the composition to stand on the coated surface for a period of time, and under conditions effective to cause blistering of the coating.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In one embodiment, the present invention provides compositions useful as a coating remover. These compositions comprise an alkylene carbonate, hydrogen peroxide, water, a first alcohol, a second alcohol, and, optionally, pine oil.
The compositions of the present invention may comprise from about 10% to about 90% by weight of an alkylene carbonate, from about 0.1% to about 20% by weight of hydrogen peroxide, from about 0.1% to about 30% by weight of water, from about 10% to about 90% by weight of a first and second alcohol, and optionally, from about 0% to about 25% by weight of pine oil. Preferably, the composition of the present invention comprises from about 20% to about 70% by weight of an alkylene carbonate, from about 0.5% to about 15% by weight of hydrogen peroxide, from about 0.5% to about 30% by weight of water, from about 20% to about 70% by weight of a first and second alcohol, and, optionally, from about 0% to about 20% by weight of pine oil.
The alkylene carbonate used in the present invention may comprise an alkylene carbonate with from about two to about eight carbon atoms. Preferably, the alkylene carbonate comprises ethylene carbonate or propylene carbonate. More preferably, the alkylene carbonate comprises propylene carbonate.
The hydrogen peroxide and water used in the present invention may be obtained from a variety of commercial sources as an aqueous hydrogen peroxide solution. Such solutions are commonly available with concentrations ranging from about one to about eighty percent. In the present invention, the aqueous hydrogen peroxide solution should have a concentration from about twenty-five percent to about fifty percent, and preferably, a concentration of about thirty-five percent.
The compositions of the present invention may be prepared using JEFFSTRIP™ FST (commercially available from the Huntsman Corporation, Houston, Tex.) as the source of the alkylene carbonate, water, and hydrogen peroxide. JEFFSTRIP™ FST is an alkylene carbonate/water/hydrogen peroxide-based composition. Representative, although not exhaustive, JEFFSTRIP™ FST compositions are disclosed in U.S. Pat. No. 6,040,284, which is incorporated by reference. If JEFFSTRIP™ FST is used in the compositions of the present invention, the compositions may comprise from about 20% to about 70% by weight of JEFFSTRIP™ FST, from about 20% to about 70% by weight of an alcohol, and, optionally, from about 0% to about 25% by weight of pine oil. Preferably, if JEFFSTRIP™ FST is used, the compositions comprise from about 30% to about 50% by weight of JEFFSTRIP™ FST, from about 30% to about 60% by weight of an alcohol, and, optionally, from about 0% to about 20% by weight of pine oil.
The first alcohol may comprise any number of alcohols, including, but not limited to, ethanol, methanol, propanol, butanol, and benzyl alcohol. Preferably, the first alcohol comprises benzyl alcohol. The second alcohol may comprise any number of alcohols, including, but not limited to, ethanol, methanol, propanol, butanol, and benzyl alcohol. Preferably, the second alcohol comprises ethanol, particularly if the composition is to be used as a varnish remover.
Surprisingly, the addition of ethanol or ethanol and pine oil to alkylene carbonate-based compositions (comprising an alkylene carbonate, a hydrogen peroxide solution, and a first alcohol) improves the blistering time of such compositions. Prior to the addition of ethanol or ethanol and pine oil, the alkylene carbonate-based compositions show blistering times of at least about 20 minutes, while subsequent to the addition of ethanol or ethanol and pine oil, the blistering times are reduced to as low as about 11 minutes. Such reduced blistering times are comparable to the blistering times of more toxic methylene chloride-based compositions, which typically have a blistering time from about 5 minutes to about 10 minutes.
The coating remover compositions of the present invention may optionally contain one or more additives. Such additives may comprise thickeners, corrosion inhibitor, chelating agents, stabilizers, surfactants, and organic co-solvents. The addition of an additive(s) may not be necessary in all situations, and is primarily dependent upon the particular application of the coating remover.
For example, a thickener may be mixed with the base composition prior to use to help retain the coating remover composition on the coated surface. The inclusion of a thickener may be necessary if the coating remover is applied to a vertical surface. A suitable thickener should not adversely react with any of the components of the base composition. Suitable thickeners may include, but are not limited to, cellulose ethers, such as hydroxypropyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose, methyl cellulose, and other alkyl or hydroxyl cellulose; silica, including colloidal silica; clays, such as bentonite and montmorillonite; alumina, including colloidal alumina; gum arabic; tragacanth; agar; sugar derivative; high molecular weight polyethylene oxides; polyvinyl pyrrolidone; and methyl vinyl ether/maleic anhydride copolymers. Generally, if a thickener is used, it should comprise from about 1 to about 4 percent by weight of the remover composition.
In addition, if the coating remover composition is to be applied to a metal surface, it may be necessary to add a corrosion inhibitor to the coating remover composition. Such corrosion inhibitors may comprise, but are not limited to, ethoxylated butynediol, petroleum sulfonates, blends of propargyl alcohol and thiourea. If used, the corrosion inhibitor typically comprises up to about 10 percent by weight of the total composition.
Further, a chelating agent may also be added to the coating remover composition to prevent or reduce the degradation of the peroxide in the remover composition. Suitable chelating agents include, but are not limited to, ethylene diamine tetraacetic acid (EDTA) and its metal salts, diethylene triamine pentaacetic acid, polyphosphates, diketone, hydroxy carboxylic acids, and phosphonic acids. When used, the chelating agent typically comprises up to about 10 percent by weight of the total composition.
Likewise, a hydrogen peroxide stabilizer may also be added to the coating remover. Such stabilizers may include, but are not limited to, C
1
Klein Howard P.
Machac, Jr. James R.
Marquis Edward T.
Woodrum Susan A.
Brown Ron D.
Gupta Yogendra N.
Huntsman Petrochemical Corporation
Peffer Nicole
Petruncio John M.
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