Bleaching and dyeing; fluid treatment and chemical modification – Cleaning or laundering – Dry cleaning
Reexamination Certificate
1999-07-21
2001-08-28
Gupta, Yogendra N. (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Cleaning or laundering
Dry cleaning
C008S187000, C510S276000, C510S285000, C510S287000, C510S289000, C510S290000, C510S291000
Reexamination Certificate
active
06280481
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods and compositions for carrying out the dry-cleaning of fabrics (e.g., garments) in liquid carbon dioxide.
BACKGROUND OF THE INVENTION
Commercial dry cleaning systems currently employ potentially toxic and environmentally harmful halocarbon solvents, such as perchloroethylene. Carbon dioxide has been proposed as an alternative to such systems in U.S. Pat. No. 4,012, 194 to Maffei.
German Patent Application DE3904514 A1 of Schollmeyer, published Aug. 23, 1990, describes a cleaning system combining various conventional anionic or nonionic surface active agents with supercritical CO
2
. The system described therein appears to combine the detergency mechanism of conventional surface active agents with the solvent power of supercritical fluid carbon dioxide. A carbon dioxide dry cleaning system effective for liquid carbon dioxide is not provided.
U.S. Pat. No. 5,683,473 to Jureller et al. (see also U.S. Pat. No. 5,683,977 to Jureller et al.) describes a dry cleaning system utilizing carbon dioxide in liquid form in combination with surfactants that contain a functional moiety that is CO
2
-philic, which surfactants are not conventionally used for detergent cleaning. Since there are numerous advantages to employing conventional surfactants (e.g., cost, ready availability, established regulatory approval, established toxicology, etc), it would be extremely desirable to have a dry cleaning system for liquid carbon dioxide that employs conventional surfactants that do not contain a CO
2
-philic group.
U.S. Pat. No. 5,858,022 to Romack et al. describes dry methods and compositions for dry cleaning in liquid carbon dioxide formulations in which a conventional surfactant (i.e., one that does not contain a CO
2
-philic group) is used in combination with an organic co-solvent. The conventional surfactant is soluble in the organic co-solvent. Ingredients such as bleaches, whiteners, softeners, sizing, starching, enzymes, hydrogen peroxide or a source of hydrogen peroxide, are described at column 3 lines 39-43, but recommendations for the structure or composition of ingredients that are particularly advantageous in carbon dioxide cleaning formulations, as opposed to functional statements thereof, are not provided.
U.S. Pat. No. 5,863,298 to Fulton et al. suggests methods of sizing and desizing yarn with a liquid carbon dioxide solvent for yarn processing, but does not suggest methods of sizing articles to be cleaned that can be used in a dry cleaning operation. Accordingly, there is a continued for additives or ingredients that can be advantageously employed with carbon dioxide cleaning formulations.
SUMMARY OF THE INVENTION
A method for dry-cleaning garments or fabrics in carbon dioxide, while also applying a sizing agent to the article, comprises contacting a garment or fabric article to be cleaned with a liquid dry cleaning composition for a time sufficient to clean the article, said liquid dry-cleaning composition comprising a mixture of carbon dioxide, surfactant, and a sizing agent. In a preferred embodiment, the sizing agent is a hydrocarbon resin having a molecular weight of from about 500 to about 3000 grams per mole. The contacting step is followed by the step of separating the article from the liquid dry cleaning composition with said sizing agent deposited thereon (preferably at a weight on goods of about 0.05 to about 3 percent).
Preferably, the liquid dry cleaning composition is at ambient temperature, of about 0° C. to 30° C. Preferably, the surfactant is soluble in the co-solvent. The surfactant may or may not be soluble in the CO
2
. Hence, in one embodiment; the surfactant may contain a CO
2
-philic group. However, in the preferred embodiment, the surfactant does not contain a CO
2
-philic group. Hence, an advantage of the present invention is that, by proper use of the co-solvent, conventional surfactants may be employed in a liquid carbon dioxide dry cleaning system.
DETAILED DESCRIPTION OF THE INVENTION
The term “clean” as used herein refers to any removal of soil, dirt, grime, or other unwanted material, whether partial or complete. The invention may be used to clean nonpolar stains (i.e., those which are at least partially made by nonpolar organic compounds such as oily soils, sebum and the like), polar stains (i.e., hydrophilic stains such as grape juice, coffee and tea stains), compound hydrophobic stains (i.e., stains from materials such as lipstick and candle wax), and particular soils (i.e., soils containing insoluble solid components such as silicates, carbon black, etc.).
Articles that can be cleaned by the method of the present invention are, in general, garments and fabrics (including woven and non-woven) formed from materials such as cotton, wool, silk, leather, rayon, polyester, acetate, fiberglass, furs, etc., formed into items such as clothing, work gloves, rags, leather goods (e.g., handbags and brief cases), etc.
1. Cleaning Processes.
The present invention may be carried out in any suitable carbon-dioxide based dry cleaning system, such as those described in U.S. Pat. Nos. 5,858,022 to Romack et al. or U.S. Pat. No. 5,683,473 to Jureller et al., the disclosures of which are incorporated by reference herein in their entirety.
Liquid dry-cleaning compositions useful for carrying out the present invention typically include water. The source of the water is not critical in all applications. The water may be added to the liquid solution before the articles to be cleaned are deposited therein, may be atmospheric water, may be the water carried by the garments, etc.
In one embodiment of the invention, better particulate cleaning may be obtained in the absence of water added to the dry-cleaning composition. There is inherently water present on or in the garments or articles to be cleaned as they are placed in the cleaning vessel. This water serves in part to adhere particulate soil to the articles to be cleaned. As the water is removed from the garments into the cleaning composition during the cleaning process, the removal of water from the article to be cleaned facilitates the removal of particulates from the articles to be cleaned. Thus, decreasing the amount of water originally in the cleaning system can serve to facilitate the cleaning of particulate soil from the articles to be cleaned by the action of the water inherently carried by the article to be cleaned.
Liquid dry-cleaning compositions useful for carrying out the present invention typically comprise:
(a) from zero (0), 0.02, 0.05 or 0.1 to 5 or 10 percent (more preferably from 0.1 to 4 percent) water;
(b) carbon dioxide (to balance; typically at least 30 percent);
(c) surfactant (preferably from 0.1 or 0.5 percent to 5 or 10 percent total, which may be comprised of one or more different surfactants); and
(d) from 0.1 to 50 percent (more preferably 1, 2 or 4 percent to 30 percent) of an organic co-solvent.
(e) a sizing agent (discussed below), preferably in an amount of from about 0.1% to 25%, preferably between 1 and 5%. Percentages herein are expressed as percentages by weight unless otherwise indicated.
The composition is provided in liquid form at ambient, or room, temperature, which will generally be between zero and 50° Centigrade. The composition is held at a pressure that maintains it in liquid form within the specified temperature range. The cleaning step is preferably carried out with the composition at ambient temperature.
The organic co-solvent is, in general, a hydrocarbon co-solvent. Typically the co-solvent is an alkane co-solvent, with C
10
to C
20
linear, branched, and cyclic alkanes, and mixtures thereof (preferably saturated) currently preferred. The organic co-solvent preferably has a flash point above 140° F., and more preferably has a flash point above 170° F. The organic co-solvent may be a mixture of compounds, such as mixtures of alkanes as given above, or mixtures of one or more alkanes. Additional compounds such as one or more alcohols (e.g., from 0 or 0.1 to 5% of a C1 to C15 alcohol (including diols, triols,
DeYoung James
Litaker Karla
Stewart Gina
Storey-Laubach Bernadette
Gupta Yogendra N.
MiCell Technologies, Inc.
Mruk Brian P.
Myers Bigel & Sibley & Sajovec
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