Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – With halogen – nitrogen – oxygen – or phosphorus containing...
Reexamination Certificate
2000-08-04
2002-06-04
Boyer, Charles (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
With halogen, nitrogen, oxygen, or phosphorus containing...
C510S130000, C510S131000, C510S138000, C510S386000, C510S387000, C510S388000
Reexamination Certificate
active
06399560
ABSTRACT:
TECHNICAL FIELD
This invention relates to a biocidal cleaning composition and the incorporation thereof into a biocidal cloth, sponge, paper, wound dressing, plastic or other substrate.
BACKGROUND ART
In domestic and hospital environments one of the most common methods of cleaning large surfaces is to wipe a cloth over such surfaces. Typically, the cloth will be moistened with water and may additionally have added a detergent or disinfectant. Cloths which do not contain a disinfectant are ineffective in controlling the growth of microorganisms. Indeed, the cloth itself may provide favourable conditions for the proliferation of such microorganisms and the action of wiping such an infected cloth over a surface may produce an effect counter to the desired outcome of making the surface more hygienic. Ordinary cleaning cloths which remain damp for a period are also notorious for the odours they develop, which are a result of microbial action.
Soaking a cloth in disinfectant provides fairly short term relief and requires the reapplication of the disinfectant to the cloth. While this method uses only modest amounts of disinfectant, the quantity is nevertheless much more than is required to achieve adequate bactericidal action. An extremely efficacious disinfectant is also required to prevent bacterial proliferation in the cleaning cloth itself, especially against the wide range of bacteria which are present in domestic and hospital situations. This somewhat unsophisticated method is also wasteful in that every time the cloth is rinsed or washed the disinfectant is removed and a new aliquot must be applied.
It has been practiced to incorporate an antimicrobial agen in a non-woven fabric as a colloidal suspension within an amorphous polymeric binder. The antimicrobial is not bound and is available to migrate to the surface of the binding agent. Such systems require an internal reservoir having a very large quantity of antimicrobial agent—typically 12 to 30 grams per square yard, and are more costly and less durable than is desired.
Cellulose sponges containing zinc pyridinethione as an active antibacterial agent are known. These sponges suffer from the drawback that a single wash in a washing machine is sufficient to remove much of the zinc pyridinethione. Thus, the sponge remains an effective weapon against bacteria for only a limited portion of its' working life, and may lead to users having false confidence in its' potency.
The reason that the zinc pyridinethione is so readily removed under normal washing conditions is that it is hydrolysed markedly at around pH 11. Zinc pyridinethione is an effective biocide, but suffers from the drawback that its optimal range of efficacy is within the pH range of 4.5 to 9.5. Many detergents and household cleaning agents have pH's above this range (for instance, washing powders give rise to solutions of around pH 11 and household bleaches have a pH of around 13), and, as in use they are often present in greater quantities than the zinc pyridinethione, are capable of rendering it ineffective.
The use of high concentrations of zinc pyridinethione to compensate for it's high loss under domestic cleaning conditions is undesirable as it has some human toxicity and is mildly irritating to the skin, and severely so to the eye. Further, the zinc pyridinethione has been shown to leach irreversibly out of the sponge over time.
There remains the problem then of providing a cleaning device, such as a cloth, sponge or similar, which will remain effective against a wide range of bacteria for a significant period of time, yet will not be unacceptably toxic.
Surprisingly, the inventor has found that one or more selected biocides, for example triclosan, dichlorophen (sometimes known as “dichlorophene” or DCP) or other chlorinated phenolic biocides, phenolic biocides, or trichlorocarban, in combination with an organometallic biocide, for example a metallic pyridinethione, exhibit a synergy which enables the combination to be effective against a wide range of bacteria under a wide range of pH conditions. Further, the addition of an acrylate binder, with or without other immobilising agents such as PVP, has also been found to render the biocidal mixture suitable for incorporation into a substrate for example a woven or non-woven cloth.
It is to be appreciated that such a biocide and method of binding is not limited to textiles used for cleaning, but may also be applicable to other materials, such as sponges, paper, wound dressings, plastics or even concrete.
DESCRIPTION OF THE INVENTION
It is to be understood that the use of the term “biocidal” throughout this specification is used in the sense that it refers to killing one or more organisms, and thus it embraces both the terms “biocidal” and “biostatic” as commonly referred to in relation to reducing or maintaining the number of microorganisms in a colony.
According to a first aspect the invention consists in a biocidal composition comprising a first biocide which is a metal pyridinethione; and a second biocide selected to be biocidally effective in a pH range complementary to the metal pyridinethione, said second biocide selected from the group consisting of halogenated phenols, phenols, derivatives of halogenated phenols, derivatives of phenols and trichlorcarban.
Examples of derivatives include diphenyl ether derivatives, methylene bridged derivatives and the like. The most preferred compounds are triclosan, dichlorophen and trichlorcarban. Examples of phenolic biocides which may be used include, but are not limited to, ortho-phenylphenol, methyl parahydroxybenzoate, propyl parahydroxybenzoate, ortho-cresol, meta-cresol and para-creso, said second biocide selected from the group consisting of halogenated phenols, phenols, derivatives of halogenated phenols, derivatives of phenols and trichlorcarban.
Examples of derivatives include diphenyl ether derivatives, methylene bridged derivatives and the like. The most preferred compounds are triclosan, dichlorophen and trichlorcarban. Examples of phenolic biocides which may be used include, but are not limited to, ortho-phenylphenol, methyl parahydroxybenzoate, propyl parahydroxybenzoate, ortho-cresol, meta-cresol and para-cresol.
Preferably the metal pyridinethione is zinc, sodium or magnesium pyridinethione, and most preferably it is zinc pyridinethione.
According to a second aspect the invention consists in a biocidal cleaning device comprising a biocidal composition according to the first aspect and a substrate.
According to a third aspect the invention consists in a method of making a biocidal cleaning device comprising the steps of combining a biocidal composition according to the first aspect with a binding agent and contacting the resultant formulation with a substrate. Preferably the method further includes the step of binding the composition to the substrate.
Preferably in a biocidal cleaning device the metal pyridinethione is present in amounts up to 2.5% of the weight of the device. More preferably it is present in amounts of 0.05 to 1.0% of the weight of the device. Most preferably it is present in amounts of 0.1 to 1.0% of the weight of the device.
Preferably in the biocidal cleaning device the second biocide is present in amounts up to 6% of the weight of the device. More preferably it is present in amounts of 0.05 to 2.0% of the weight of the device. Most preferably it is present in amounts of 0.1 to 2.0% of the weight of the device.
Desirably the biocidal composition is prepared as a concentrate which is diluted prior to impregnation into the substrate. In the concentrate the metal pyridinethione is present in amounts up to 40% w/w, and more preferably 20 to 30% w/w.
Preferably the second biocide is present in the biocidal concentrate in amounts up to 60% w/w, and more preferably 20 to 40% w/w.
The biocidal composition or concentrate may also include, in any combination, a mineral oil, (PVP) polyvinylpyrrolidone, an alcoholic solvent, an anionic surfactant, a non-ionic surfactant and water.
The substrate for use in the biocidal clean
Kritzler Steven
Kwon Hyo Sang
Boyer Charles
Leydig , Voit & Mayer, Ltd.
Novapharm Research (Australia) Pty Ltd.
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