Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-12-20
2003-08-12
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S303000, C510S304000, C510S309000, C510S372000, C510S375000, C510S466000, C510S499000, C510S506000
Reexamination Certificate
active
06605580
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of bleaching compositions to remove stains from articles, in particular textile articles. In addition the present invention relates to a method of preparing a bleaching composition and method to bleach articles.
BACKGROUND OF THE INVENTION
It is often problematic to remove certain stains when cleaning articles having either hard or soft surfaces such as metal, ceramic, plastic or textile articles. It is known in the art to use bleach components to remove these stains. More recently, cleaning with carbon dioxide has been described. Dense phase carbon dioxide has been suggested as an alternative to perchloroethylene for health and environmental reasons. For example, a dry cleaning system in which chilled liquid carbon dioxide is used to extract soils from fabrics is described in U.S. Pat. No. 4,012,194. However, it has been recognised that additives are needed to boost the cleaning by this medium. For example, the use of ethoxylated tertiary acetylenic alcohol and diol surfactants for boosting the cleaning performance from condensed phase carbon dioxide are taught in U.S. Pat. No. 5,789,505. U.S. Pat. No. 5,431,843 discloses a perhydrolysis system for use in condensed fluid medium for bleaching of stained garments. This perhydrolysis system comprises two essential components: hydrogen peroxide and an organic peracid precursor. The examples seem to indicate that a combination of hydrogen peroxide and nonanoyloxyglycoylphenyl sulfonate (NOGPS) results in a better overall stain removal when compared to hydrogen peroxide alone. To obtain these results, the bleaching process takes place for at least 1 hour. U.S. Pat. No. 5,676,705 describes the use of organic peracid precursor in a dry cleaning process using carbon dioxide. Herein, both the preformed peracids and the directly added organic peracid precursor should be soluble in densified carbon dioxide.
The use of inorganic bleaching agents for removal of soil from garments in aqueous systems has been known for a long time. U.S. Pat. No. 3,332,882 teaches the use of bleaches in combination with triazine activators. U.S. Pat. No. 4,300,897 teaches a method of bleaching using peroxomonosulfate-based compositions. WO-A-9923197 teaches a process of soaking fabrics with a liquid aqueous persulfate salt-containing composition. And, WO-A-9921950 teaches the use of peroxonitrite based bleaching systems. However neither of these documents discloses or suggests to the skilled person that inorganic bleaching agent could be effective in a bleaching method wherein the medium is mainly carbon dioxide. U.S. Pat. No. 5,431,843 only exemplifies the use of liquid hydrogen peroxide in combination with an organic peracid precursor. For bleaching in carbon dioxide, perborate, percarbonate or persulfate are mentioned as possible sources of peroxygen but only in combination with an organic peracid precursor. There is no disclosure or suggestion for the skilled person that an inorganic bleaching agent alone would have an effective bleaching effect.
Although organic peracids and/or precursor systems are generally effective they still exhibit several disadvantages. For example, these organic compounds are moderately sophisticated molecules requiring multi-step manufacturing processes resulting in high capital costs. Also, these precursor systems have large formulation space requirements as they also need addition of hydrogen peroxide and/or a hydrogen peroxide delivery system. Consequently, a significant proportion of the cleaning formulation must be devoted to the bleach components, leaving less room for other active ingredients and complicating the development of concentrated formulations. Moreover, organic precursor systems do not bleach very efficiently in situations wherein short bleach times are desired and processing environment is acidic or pH neutral.
Accordingly, it is an object of the invention to provide an alternative bleaching composition and method of bleaching which shows effective stain removal but does not display one or more of these drawbacks when applied in a bleaching process. One particular object of the invention is to provide a bleaching composition and a bleaching method which are economical and require short bleach times. Another object of the invention is to provide a bleaching composition and a method of bleaching which are particularly suitable for removing grass, tea and blackcurrant stains.
Surprisingly, we have now found that one or more of these objects can be achieved by the inventive bleaching composition and method of bleaching which are substantially free of organic peracid and precursors thereof and still show a remarkably effective stain removal.
DEFINITION OF THE INVENTION
Accordingly, in a first aspect of the invention a bleaching composition is provided comprising
a) a bleach-effective amount of an inorganic bleaching agent;
b) a bleach-compatible solvent
c) 0 to 10 wt % of a surfactant;
d) less than 10 wt % of a modifier; and
e) an effective dry cleaning amount of densified carbon dioxide, said composition being essentially free of organic peracid or precursor thereof.
In a second aspect of the invention a method to prepare the inventive composition is provided, characterised in that said method comprises the steps of
a) mixing the inorganic bleaching agent in a bleach-compatible solvent; and
b) mixing the solvent and inorganic bleaching agent of step a) with the carbon dioxide.
In a third aspect of the invention a method to bleach articles is provided, comprising the following steps:
a) mixing a bleach-effective amount of an inorganic bleaching agent in a bleach-compatible solvent, preferably an aqueous solvent; and
b) contacting said article with a bleaching composition according the invention, said composition comprising the resulting mixture of step a).
Preferably, the inventive composition and method is suitable to bleach articles in less than 45 min.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is particularly advantageous for bleaching methods that require a short period of time. U.S. Pat. No. 5,431,843 describes bleaching times of 1 hour for effective stain removal. Unexpectedly we have now found that the present invention provides effective bleaching in 45 minutes or less. Another advantage of the present invention is the simplicity. Without wishing to be bound by any theory it is believed that precursors only at high pH can form organic peracids effectively by perhydrolysis of the precursor. Since carbon dioxide has a low pH, special measures have to be taken to ensure the formation of relatively unstable peracids in a separate premix process. Furthermore, it is believed that the low temperatures used in carbon dioxide cleaning will also slow this reaction. Yet another advantage of the present invention is that it is remarkably effective on a variety of stains, especially grass, tea and black currant stains. The present invention is especially suitable to bleach and clean garments but may also be employed to bleach articles with hard surfaces.
For purposes of the invention, the following definitions are used:
“The bleaching composition” describes the total of the liquid carbon dioxide, the inorganic bleaching agent, the modifier if present and optionally other additives.
“Additives” are compounds to enhance the cleaning effect of the bleaching composition such as surfactants, whiteners, softeners, enzymes, perfume and antistat.
“Liquid carbon dioxide” means carbon dioxide which has a temperature of about 30° C. or less.
“Supercritical fluid carbon dioxide” means carbon dioxide which is at or above the critical temperature of 31° C. and the critical pressure of 7.2 Mpa (71 atmospheres) and which cannot be condensed into a liquid phase despite the addition of further pressure.
The term “densified carbon dioxide” encompasses both liquid and supercritical fluid carbon dioxide.
The composition used in the inventive bleaching method should be essentially free of organic peracid and precursor thereof. For this purpose “essentially f
Bijl Dirk Johannes
Hage Ronald
Kevelam Jan
Koek Jean Hypolites
Murphy Dennis Stephen
LandOfFree
Bleaching composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bleaching composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bleaching composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3093794