Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
2000-08-04
2002-03-19
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S191000, C510S199000, C510S238000, C510S254000, C510S365000, C510S499000, C510S505000, C134S040000
Reexamination Certificate
active
06358907
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to aerosol formulations for removing paint, grease, and other residues from various substrates and methods of preparing the same.
BACKGROUND OF THE INVENTION
For decades, strong acids and halocarbon solvent-based compositions were employed in stripping various protective coatings from metal and other substrates. Increased awareness of the detrimental impact of such paint strippers on health and environment, in recent years, resulted in government legislative bodies all over the world restricting and/or prohibiting the use of these materials.
Various hazardous solvents, such as methylene chloride and methyl alcohol, are often included in paint stripper compositions. Since these solvents may cause health and environmental problems when airborne, they are not suitable for use as an aerosol.
Most currently commercially available aerosol compositions for removing grease from oven surfaces and other substrates emit unpleasant odors and are caustic. Furthermore, these compositions often are not environmentally friendly.
Therefore, there is a need for effective paint stripper compositions which do not contain strong acids, halocarbon solvents, or other hazardous solvents and which may be applied as an aerosol. Also, there is a need for environmentally friendly aerosol grease removing compositions which are not odorous.
SUMMARY OF THE INVENTION
The present invention is directed to an aerosol formulation comprising (A) a composition comprising (i) from about 5 to about 50% by weight of aromatic alcohol, (ii) from about 0.5 to about 5.0% by weight of an accelerator, and (iii) from about 15 to about 60% by weight of water, based upon 100% weight of total composition; and (B) a propellant. The aerosol formulation of the present invention is effective at removing paint, coatings, grease, and other residues from substrates. It is also non-corrosive or only slightly corrosive to substrates, environmentally safe, non-hazardous, nonflammable, nontoxic, low odor, and fully biodegradable.
Another embodiment of the invention is an aerosol can containing the aerosol formulation of the present invention.
Yet another embodiment of the invention is a method of preparing the aerosol formulation comprising the steps of (A) dispersing (i) a polar phase containing (a) from about 10 to about 45 parts by weight of water and (b) from about 0.3 to about 4 parts by weight of an accelerator into a (ii) a non-polar phase containing from about 3 to about 35 parts by weight of aromatic alcohol to form a composition, and (B) adding from about 20 to about 50 parts by weight of a propellant to the composition to form the aerosol formulation.
Yet another embodiment of the invention is a method for removing paint or a coating from a substrate comprising applying a paint or coating removing effective amount of the aerosol formulation of the present invention.
Yet another embodiment of the invention is a method for removing grease and other residues from a substrate comprising applying a grease or residue removing effective amount of the aerosol formulation of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The aerosol formulation of the present invention comprises (A) a composition and (B) a propellent. The composition of the present invention comprises (i) from about 5 to about 50% by weight of (a) an aromatic alcohol having the formula
where X, Y, and Z are all hydrogen or two hydrogens and a methyl, (b) an aromatic alcohol having the formula
where R is ethylene, propylene, or isopropylene, or (c) a mixture thereof; (ii) from about 0.5 to about 5% by weight of an accelerator; and (iii) from about 15 to about 60% by weight of water, based upon 100% weight of total composition.
The composition typically has a pH of from about 7 to about 11 and preferably a pH of less than about 10. According to a preferred embodiment, the pH of the composition ranges from about 8 to about 9.
Suitable aromatic alcohols include, but are not limited to, benzyl alcohol, phenoxy propanol, phenoxy ethanol, and any combination of any of the foregoing. Preferably, the aromatic alcohol is benzyl alcohol. The composition preferably comprises from about 30 to about 40% by weight of aromatic alcohol, based upon 100% weight of total composition.
Suitable accelerators include, but are not limited to, alkanolamines, such as monoethanolamine, triethanolamine, and any combination of any of the foregoing. Preferably, the composition contains both monoethanolamine and triethanolamine. The weight ratio of monoethanolamine to triethanolamine is preferably from about 2:1 to about 1:2 and more preferably about 1:1. The composition preferably comprises from about 0.5 to about 3% by weight of an accelerator, based upon 100% weight of total composition.
The presence of deionized water in the composition enhances the overall stripping effectiveness of the composition. When the protective coating on a substrate to which the composition is applied is polar, e.g., polyurethanes, the presence of a solvent with a high dielectric constant such as water (∈=80.2@20° C.) has a positive effect in separating charged areas, thus allowing other solvents in the composition to soften the coating.
The water preferably contains no more than about 1% by weight of dissolved inorganic salts and preferably less than about 200 ppm. Distilled or deionized water having an electrical conductivity less than about 400 mho/cm is particularly preferred.
The composition preferably comprises from about 30 to about 60% by weight of water, based upon 100% weight of total composition.
Corrosion inhibitors may be added to the composition to control the corrosive action of the composition on an aerosol spray can as well as on metal substrates on which the composition is applied. Suitable corrosion inhibitors include, but are not limited, 2-mercaptobenzothiazole, toluoltriazole, benzotriazole, 2(3H)-benzothiazolethione, morpholine, sodium nitrite, sodium benzoate, and any combination of any of the foregoing. Preferred corrosion inhibitors include, but are not limited to, 2-mercaptobenzothiazole, morpholine, sodium nitrite, sodium benzoate, and any combination of any of the foregoing. The composition typically comprises a corrosion inhibiting or corrosion retarding effective amount of corrosion inhibitor. Preferably, the composition comprises from about 0.1 to about 3% by weight and more preferably from about 0.5 to about 1% by weight of corrosion inhibitor, based upon 100% weight of total composition.
The composition may also include an aromatic ether having the formula R
1
—CH
2
—O—CH
2
—R
2
where R
1
and R
2
are hydrogen and phenyl or both phenyl. A preferred aromatic ether is benzyl ether. The composition preferably includes from about 1 to about 20% by weight of aromatic ether based upon 100% weight of total composition. The weight ratio of aromatic alcohol to aromatic ether is preferably from about 10:1 to about 5:1 and more preferably about 7:1.
An aromatic hydrocarbon cosolvent may be included in the composition. The aromatic hydrocarbon cosolvent may be a mixture of one or more aromatic hydrocarbon solvents. The aromatic hydrocarbon cosolvent improves the stability of the composition thereby increasing the shelf life of the composition. It also improves the rheological properties of the composition and the speed of penetration of the composition into paints, coatings, grease, and other residues. Furthermore, the aromatic hydrocarbon solvent reduces the surface tension and evaporation rate of the composition. Preferably, the aromatic hydrocarbon solvent has a flash point above about 150° F. and more preferably above about 190° F. Naphthalene depleted aromatic hydrocarbons are preferable since naphthalene has a noxious odor and is hazardous. Suitable aromatic hydrocarbon cosolvents include, but are not limited to, Aromatic 200ND™ available from Exxon Chemical Co. of Houston, Tex.; Solvesso 200™ available from Esso Corp. of Toronto, Canada; metaphenoxy benzyl alcohol; and any combination of any of the foregoing.
Delcotto Gregory
Napier Environmental Technologies Inc.
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