Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2001-11-08
2004-10-12
Mruk, Brian P. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C568S420000, C568S421000, C568S449000, C526S315000, C424S078080, C424S078370, C422S036000, C514S703000
Reexamination Certificate
active
06803356
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to antimicrobial polymeric compositions. More particularly, the antimicrobial polymeric compositions of the present invention contain compounds having a polyacrolein sub-unit with its aldehyde group in its free, hydrated, hemi-acetal or acetal form, and having biostatic and/or biocidal properties. The invention is directed to compositions containing these polymeric compounds and the biostatic and/or biocidal uses of these compositions.
BACKGROUND ART
The broad-based antimicrobial properties of polymers (hereinafter called the “subject polymers”) having the repeating polymeric unit:
or this unit in its hydrated, hemi-acetal or acetal form, represented by the formulae:
wherein R is hydrogen or alkyl and n is an integer of one or more, have been demonstrated previously (Melrose et al., International Patent Publication WO 88/04671). The subject polymers described therein include poly(2-propenal, 2-propenoic acid).
It has also been noted previously (Melrose, International Patent Publication WO 96/38186) that poly(2-propenal, 2-propenoic acid) is formed when the aldehyde groups of poly(2-propenal) syn polyacrolein are partially auto-oxidised to carboxyl groups, by heating the dry polymer in air, to 100° C. and preferably to between 80° C. and 100° C. It was further noted that the resulting polymer is soluble in dilute aqueous bases, for example aqueous sodium carbonate.
An earlier disclosure (Werle et al., Australian Patent Application 11686/95, now lapsed) claimed solubility of the subject polymers in polyols—but not solubility in aqueous media, following heating to 75° C. It was further claimed that subsequent to the heating to 75° C., brief treatment with sodium hydroxide gave rise to aqueous solubility and apparently as a result, increased antimicrobial activity.
To increase the stability of compositions containing the subject polymers, Melrose & Huxham (International Patent Application PCT/AU99/00578) have formulated compositions with anionic surfactants. Additionally, this prior art revealed that in basic compositions, in contrast to acidic compositions, the subject polymers have faster antimicrobial activity, but are less stable.
It is particularly desirable that the subject polymers should not be unstable, yielding acrolein, as this monomer is very irritating to the eyes, lungs, tissues and skin.
It is one object of the present invention to provide methods of preparing compositions, these methods producing a new configuration of the subject polymers and in particular of poly(2-propenal, 2-propenoic acid), and which have enhanced antimicrobial activity.
It is a further object of the present invention to provide methods of preparing compositions, these methods producing a new configuration of the subject polymers and in particular of poly(2-propenal, 2-propenoic acid), and which better retain antimicrobial activity.
It is a still further object of the present invention to provide methods of preparing compositions, these methods producing a new configuration of the subject polymers and in particular of poly(2-propenal, 2-propenoic acid), and which contain less free acrolein.
It is a yet still further object of the present invention to provide compositions containing a new configuration of the subject polymers and in particular of poly(2-propenal, 2-propenoic acid) which are efficacious disinfectants or antiseptics.
Throughout the specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
DISCLOSURE OF THE INVENTION
In accordance with the present invention there is provided a method for improving the antimicrobial activity of a polymer derived from acrolein monomer wherein the polymer has been oxidized in air to form an oxidised acrolein polymer comprising carboxyl groups, said method comprising:
providing a solution of the oxidized acrolein polymer comprising carboxyl groups in a mixture containing water and a hydroxylic solvent including an alcohol selected from the group consisting of polyols, polyethylene glycols and alkanols; and
heating the solution at a temperature in the range of from 40 to 150° C. for a period sufficient to improve the antimicrobial activity of the acrolein polymer.
Still preferably, the polymers are heated in the range of 40 to 115° C.
Still further preferably, the polymers are heated in the range of 70-90° C.
Preferably, the polymers are heated for a period of between 1 to 1,400 hours, thereby increasing antimicrobial activity of the polymers.
Still preferably, the polymers are heated for a period of between 10 to 60 hours.
In one form of the invention the polymers are heated in the presence of one or more of polyethylene glycol, polyol or alkanol, thereby providing one or both of enhanced stability or enhanced anti microbial activity. Water is invariably present in these alcohols.
Preferably, polyethylene glycol is present during the preparation of the polymers in the amount of between 50 and 99% by weight.
Still preferably, poly ethylene glycol is present during preparation of the polymers in the amount of between 64 and 95% by weight.
In a further form of the invention, base or alkali is added to the polymers before and/or during heating, thereby enhancing the antimicrobial activity of the polymers.
Preferably, the addition of the base or alkali brings the pH of the polymers to between 7 and 9.
Still preferably, the pH is about 8. Sodium hydroxide may be the base added.
In a still further form of the invention, the release of free acrolein monomer is inhibited, thereby the polymers are less likely to present a source of tissue or dermal irritation.
Preferably, the polymer is initially heated, predominantly in the dry state, to between 80 and 100° C.
Still preferably, the polymer is initially heated to about 85° C.
In accordance with the present invention there is further provided an antimicrobial compound or composition prepared by one or more of the methods described hereinabove.
In accordance with the present invention there is still further provided a preservative compound or composition prepared by one or more of the methods described hereinabove.
In accordance with the present invention there is yet still further provided a disinfectant or antiseptic compound or composition prepared wholly or in part by the methods described hereinabove.
Preferably, the disinfectant or antiseptic compound or composition has a pH greater than 6, thereby enhancing antimicrobial activity.
In accordance with the present invention, there are provided methods for the preparation of a new configuration of the subject polymers including poly(2-propenal, 2-propenoic acid) and of compositions therefrom, whereby the compositions exhibit increased antimicrobial activity, and/or increased stability and/or contain less free acrolein, thus making the polymers and/or their compositions more suitable as preservatives, and/or active ingredients in disinfectants and/or, antiseptics, under acidic or basic conditions.
BEST MODE(S) FOR CARRYING OUT THE INVENTION
Since the prior art recorded some instability of poly(2-propenal, 2-propenoic acid), as evidenced by loss of antimicrobial activity of its compositions, the routine procedure in industry was then followed in our laboratories, of quantitatively determining this instability by standard “accelerated ageing” at elevated temperature, ie. at 40° C. However, to our greatest surprise, the elevated temperature of “ageing” poly(2-propenal, 2-propenoic acid) in aqueous or in aqueous-polyethylene glycol solutions at 40° C., not only slowed the decrease in antimicrobial activity—but in fact, actually increased antimicrobial activity of the poly(2-propenal, 2-propenoic acid), see Example 2(a) and (b). This finding is totally contradictory and unexpected in view of the prior art which predicts that the rise in temperature should lead to “accelerated ageing”, ie. accelerated
Daly Gerry
Huxham Andrew James
Melrose Graham John Hamilton
Chemeq Ltd.
Mruk Brian P.
Nixon & Peabody LLP
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