Plant protecting and regulating compositions – Plant growth regulating compositions – Aquatic plant regulator
Reexamination Certificate
2000-01-03
2001-09-18
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Aquatic plant regulator
C504S155000
Reexamination Certificate
active
06291397
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of Invention
The present invention is related to compositions for removing algae from a variety of surfaces.
2. Description of the Related Art
Especially in hot and humid environments, algae can grow on a variety of surfaces, both interior as well as exterior. The removal of algae from exterior as well as interior surfaces can be a time-consuming and rather unpleasant job, in particular where the surface area to be treated is rather large and/or exceptionally dirty with oil. A common algaecide is sodium hypochlorite. DPC Industries, Inc. of Houston, Tex. markets a useful algaecide composition, “DIXICHLOR”, which consists of sodium hypochlorite, sodium chloride, sodium hydroxide, and water. Another algaecide composition, which was invented by the inventor of the present invention and the subject of U.S. Pat. No. 5,856,272 (and is incorporated by reference herein in its entirety) is currently marketed by Magnum Cleaning Products (Galveston, Tex.) as MAGNACHLOR. MAGNACHLOR contains about 10% sodium hypochlorite. To the best of the inventor's knowledge, most if not all algaecide agents on the market comprise sodium hypochlorite, which is believed to be necessary in eradicating algae.
Sodium hypochlorite, while an excellent algaecidal agent, can be hazardous to work with. The compound reacts vigorously with sodium hydroxide, for example, resulting in noxious fumes that are very irritating to the user's eyes, causing blurring and tearing. The compound may also cause skin irritation as well as irritation to sensitive mucousal membranes of the mouth and nose when inhaled.
Most algaecidal agents are formulated and marketed as liquids; however, such liquid formulations have certain undesirable disadvantages, notwithstanding their overall effectiveness in eradicating algae. For example, liquid algaecidal agents comprising sodium hypochlorite have limited shelf lives, generally ranging from six to eight months. Transportation of liquid formulations can also be expensive and hazardous if large quantities of the algaecidal composition are desired (generally, a gallon solution comprises about 10% of sodium hypochlorite). Conversely, a concentrated algaecidal solid formulation can be more easily shipped, and more importantly, has an indefinite shelf-life, since the solid compounds comprising the solid formulation would not be activated until mixed in water or other suitable liquid carrier.
It would therefore be desirable to have an algaecide formulated in a concentrated solid that, just prior to use, can simply be mixed with water or other suitable liquid carrier in a single step. While sodium hypochlorite is available in solid form, it will not work effectively alone if mixed in water and then applied to an algae-covered surface. Moreover, combining sodium hypochlorite and sodium hydroxide in solid form will not effectively kill the algae, since this combination, at the desired algaecidal percentages (about 10% sodium hypochlorite and 1% sodium hydroxide) exceeds the solubility of sodium hypochlorite, thereby resulting in the sodium hypochlorite falling out of solution upon mixing.
SUMMARY OF THE INVENTION
The present invention is related to novel algaecidal solid mixtures that may be mixed, in one step, with water just prior to application onto an algae-covered surface. The algaecidal mixture and resulting solution is less hazardous to work with compared to other algaecidal agents on the market, is easier and less expensive to transport in solid form, and has an indefinite shelf-life in solid form, as well.
Specifically, the present invention is directed to compositions comprising a combination of alkali hydroxides, such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; a metal sulfate such as aluminum sulfate, calcium sulfate, and zinc sulfate; and chlorinated isocyanurates, preferably sodium dichloro-s-triazinetrione. The present invention is also directed to a method of removing algae from a variety of surfaces and comprises applying an algaecidal solution to an algae-covered surface, followed by a water rinse after a time sufficient to allow the algaecidal solution to kill the algae. The algaecidal solution comprises the components of the algaecidal mixture, namely a combination of alkali hydroxides, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and lithium hydroxide; a metal sulfate such as aluminum sulfate, calcium sulfate, and zinc sulfate; and chlorinated isocyanurates, preferably sodium dichloro-s-triazinetrione. The algaecidal composition further includes a buffer to prevent the components from falling out of solution after mixing in water while at the same time allowing the chlorine that results upon dissolution to be released after about 12 hours post-solution. A preferred buffer comprises about 25 to 30% of an alkali hypochlorite, preferably lithium hypochlorite. A buffer vended by VanWaters & Rodgers, Inc. comprises lithium hypochlorite (25-30%), sodium chloride (36%), sodium sulfate (13%), potassium sulfate (6%), lithium chloride (4%), lithium chlorate (2%), lithium hydroxide (1%), and water (7%).
The present invention is also directed to a method of removing algae comprising (1) combining an algaecidal mixture, comprising, in solid form, alkali hydroxides, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and lithium hydroxide; a metal sulfate such as aluminum sulfate, calcium sulfate, and zinc sulfate; chlorinated isocyanurates, preferably sodium dichloro-s-triazinetrione; and a buffer comprising an alkali (e.g. lithium) hypochlorite; (2) mixing the algaecidal mixture with water to form an algeacidal solution; (3) applying the algaecidal solution to a surface having evidence of algae growth; and (4) rinsing the treated surface with water or other aqueous liquid.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The inventive algaecidal composition is a concentrated solid mixture of alkali hydroxides, chlorinated isocyanurates, metal sulfates, and a buffer. A preferred chlorinated isocyanurate is sodium dichloro-s-triazinetrione, vended by Asepsis Inc. (Avondale Estates, Georgia) as HYDROTECH GRANULAR CONCENTRATE. The isocyanurates function as the primary algaecidal agent. In the preferred embodiment, the solid concentrated mixture comprises an amount of sodium dichloro-s-triazinetrione such that in solution, the resulting algaecidal solution comprises from about 3.5 to about 20 w/w % of the sodium dichloro-s-trianzinetrione, depending upon the desired algaecide solution strength. The solid mixture comprises about 36% of alkali dichloro-s-triazinetrione.
The inventive mixture also includes an alkali hydroxide, preferably sodium hydroxide, which comprises from about 2 to 12 w/w % of the resulting algaecidal solution (the solid mixtures comprises about 62% of the alkali hydroxide). Other alkali metals, such as potassium or lithium, may be employed, as well. The sodium hydroxide is present to disintegrate the algae from at its root, and further aids in algae removal up and away from the treated surface by a “bubbling” action similar to that of hydrogen peroxide.
Preferably, the inventive algaecide mixture contains a component to inhibit future algae growth. A suitable algae-growth inhibitor is a metal sulfate, such as copper sulfate, aluminum sulfate, and zinc sulfate. [Only one of the sulfates should be used in a given formulation] A preferred percentage of metal sulfate in the algaecidal solution is at least about 0.012 w/w % (the solid mixture comprises about 0.2% of the metal sulfate).
The inventive algaecide mixture further includes a buffer to prevent the components from falling out of solution. A preferred buffer comprises an alkali hypochlorite, such as lithium hypochlorite. A preferred buffer vended by VanWaters & Rodgers, Inc. comprises lithium hypochlorite (25-30%), sodium chloride (36%), sodium sulfate (13%), potassium sulfate (6%), lithium chloride (4%), lithium chlorate (2%), lithium hydroxide (1%), and water (7%). The buffer comprises about 2% of the solid mix
Barrow Laura G.
Clardy S. Mark
LandOfFree
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