Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-11-16
2002-01-15
Boyer, Charles (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S202000, C510S203000, C510S206000, C510S209000, C510S211000, C510S242000, C510S417000, C510S432000, C510S469000, C510S431000, C510S413000, C510S421000, C516S076000, C516S199000, C134S038000
Reexamination Certificate
active
06339053
ABSTRACT:
The present invention relates to an aqueous composition for removing organic coatings from a surface.
PCT Patent Application No. WO 97124409 (Eco Solutions Limited) (the disclosure of which is incorporated herein by reference) discloses a predominantly aqueous composition for plasticising or softening paint, varnish and similar coatings prior to stripping the coating from a surface, comprising preferably:
(a) an effective amount of a mixture of (a1) at least one non-toxic compound of formula I
wherein R,R
1
and R
2
, which may be the same or different, represent lower alkyl, phenyl or lower alkyl-phenyl groups
and (a2) at least one non-toxic lower alkyl ester (including diester) of a C
2-20
carboxylic acid or at least one non-toxic C
4-12
alkanol;
(b) an effective amount of at least one surfactant to allow the composition to exist as a stable emulsion, the surfactant(s) being selected from nonionic water-soluble block copolymers of more than one alkylene oxide; and
(c) water in an amount sufficient to comprise the major portion of the composition.
Japanese Patent Application Kokai No. 55-157740 (1980) (Ube Kyosan K.K.) (the disclosure of which is incorporated herein by reference) discloses a predominantly aqueous composition described as a liquid detergent for removing a variety of stains and coatings from hard surfaces, comprising from 1 to 20% by weight of succinic acid diester, from 0.1 to 5 (but not including 5) % by weight of anionic surfactant, from 1 to 40% by weight of nonionic surfactant and from 60 to 95% by weight of water.
EP-A-0294041 (Minnesota Mining and Manufacturing Company) (the disclosure of which is incorporated herein by reference) discloses a predominantly aqueous composition for removing coatings such as paint, containing up to about 50% by weight of dibasic acid esters, small amounts of thickening agents (clay/cellulose mixtures), and at least about 50% weight of water, together with additional ingredients such as surfactants.
EP-A-0407952 (Georg Scheidl Jr. GmbH) (the disclosure of which is incorporated herein by reference) discloses a viscous, pasty or gel-like aqueous composition, said to be an improvement on the compositions of EP-A-0294041, in which the paint-softening “solvents” generally comprise 20 to 60% by weight of the composition, preferably 30 to 45%, the remainder of the composition being an aqueous solution of common surfactants with one or more common thickeners. Dibasic esters are generally indicated as possible “solvents”, although none is specifically mentioned. Laponite RD is exemplified (Examples G, H and I) as an example of a common thickener.
The prior art compositions described above have limitations from a commercial point of view. The active and surfactant components are speciality chemicals which are not available worldwide. As a result, it can be desirable to transport the compositions in order to supply the less industrialised countries. The high water content is undesirable, as it is clearly inefficient to transport large quantities of water by aircraft, truck or ship. On the other hand, it has not hitherto been possible to obtain a composition with lower water content that has an activity equal to or better than traditional solvent-based (e.g. methylene chloride) coating removers.
DE-A-3438399 (Chemische Werke Kluthe GmbH & Co.) (the disclosure of which is incorporated herein by reference) discloses generally an aqueous paint-stripping agent containing methyl and/or ethyl and/or propyl and/or butyl esters of succinic acid and/or glutaric acid and/or adipic acid and provides an example (Example 1) of such a composition in which there is a total of 66% by weight dibasic acid esters (dimethyl succinate, dimethyl glutarate and dimethyl adipate), 2% by weight of an organic thickening agent (cellulose acetobutyrate) and 5% by weight of water, together with additional ingredients such as surfactants. However, as evidenced by data contained in EP-A-0294041, such a composition is less effective than a conventional methylene chloride paint stripper.
EP-A-0648820 (Qyentos Corporation) (the disclosure of which is incorporated herein by reference) discloses further aqueous compositions employing rather low levels of water and high levels of active and carrier organics (e.g. dimethyl succinate, dimethyl adipate and dimethyl glutarate) dispersed in the water by means of surfactants. As potential surfactants there are generally mentioned alkylene-oxide (ethylene oxide or propylene oxide) added type nonionic surface active agents.
Neither of these prior art documents offers a concentrated cleaning fluid that can constitute a suitable concentrate for shipping prior to dilution with water to yield a diluted formulation with retained activity.
Therefore, in the field of household or commercial preparations which soften or remove an organic coating such as paint, varnish, grease, ink or dirt, there is a continuing need for a concentrated fluid that is preferably clear and non-streaking, effective against a wide range of coatings, and capable, if desired, of being diluted and optionally thickened without substantial loss of activity.
According to the present invention, there is provided an aqueous composition for softening or removing organic coatings, the composition comprising:
(a) an effective amount of a mixture of (a1) at least one non-toxic compound of formula I
wherein R,R
1
and R
2
, which may be the same or different, represent lower alkyl, phenyl or lower alkyl-phenyl groups
and (a2) at least one non-toxic lower alkyl ester of a C
2-2
carboxylic acid or at least one non-toxic C
4-12
alkanol;
(b) an effective amount of at least one surfactant to allow the composition to exist as a stable emulsion, the surfactant (s) being selected from nonionic water-soluble block copolymers of more than one alkylene oxide; and
(c) water;
characterised in that component (c) (water) is present in an amount of less than about 50% by weight and/or volume of component (a) and in that the composition exists as a stable microemulsion.
It should be noted that the phrase “stable emulsion” or “stable microemulsion” used herein refers particularly to an emulsion or microemulsion which is stable with respect to separation into unemulsified phases over a period of time normally required for such a composition, typically a few weeks or months. The word “microemulsion” refers to emulsions, including suspensions and dispersions, in which the emulsified droplets are of a size less than about 0.1 &mgr;m, so that no milkiness results.
The term “lower alkyl” refers in particular to alkyl groups containing up to about 8 carbon atoms, for example methyl, ethyl, n-propyl, s-propyl, n-butyl, s-butyl, t-butyl, pentyl and hexyl groups. Such alkyl groups may optionally be mono- or poly-substituted, for example by one or more substituents selected from halo, nitro, amino, C
1-4
alkylamino, di-C
1-4
alkylamino, hydroxy, C
1-4
alkoxy, carboxy, (C
1-4
alkyl)carbonyl, (C
1-4
alkoxy)-carbonyl, C
2-4
alkanoyloxy, (C
1-4
alkyl)carbamoyl, aryl and cycloalkyl groups or salt derivatives thereof. Phenyl portions of compounds of formula I may optionally be similarly mono- or poly-substituted.
The expression “non-toxic” used herein refers to an acceptably low level of toxicity when a compound is present at an effective amount, and not necessarily to a complete absence of toxic effects. In particular, compounds which have only a temporary toxic effect and do no significant permanent harm, will be referred to and understood as “non-toxic” herein. Particular toxic effects which are to be avoided in the compositions of the present invention are carcinogenicity, teratogenicity and mutagenicity.
The compound of formula I forming component (a1) of the preferred composition is preferably water-soluble or water-miscible, if necessary with the assistance of solubilising agents, but insoluble or non-miscible compounds may be used provided that they are emulsifiable or suspendible, if necessary with the assistance of emulsifying and/or suspending agents.
As a preferred compound of formula
Chivers Ivor M.
Reynolds Paul A.
Boyer Charles
Eco Solutions Limited
Welsh & Katz Ltd.
LandOfFree
Aqueous composition for removing coatings does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Aqueous composition for removing coatings, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aqueous composition for removing coatings will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2856013