Bleaching and dyeing; fluid treatment and chemical modification – Cleaning or laundering – Dry cleaning
Reexamination Certificate
2000-07-20
2002-12-10
Webb, Gregory E. (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Cleaning or laundering
Dry cleaning
C008S137000, C510S283000, C134S010000
Reexamination Certificate
active
06491730
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. Accordingly, there is a continued need 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, said garment or fabric including a stained portion comprises pre-treating the stained portion of a garment or fabric article to be cleaned with a liquid pretreatment composition, said composition preferably containing a pretreatment surfactant. The pretreatment step is followed by the steps of contacting the article 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 and a cleaning surfactant; and then separating the article from the liquid dry cleaning composition.
In one embodiment, the pretreatment surfactant is one which does not contain a CO
2
-philic group. In another embodiment, the pretreatment surfactant is one which does contain a CO
2
-philic group (e.g., a fluoropolymer or a fluorine-containing segment such as a fluoroacrylate polymer, or a siloxane polymer or siloxane containing segment), which CO
2
-philic group is in turn coupled to a hydrophilic or lipophilic group. When present, the pretreatment surfactant (either type) is preferably included in an amount of from 0.05, 1, 2, or 3 percent to 5 or 10 percent by weight.
Without wishing to be bound to any particular theory of the invention, it is believed that surfactants that do not contain a CO
2
-philic group remain localized in the area to which they are applied to a greater extent during the cleaning cycle in the presence of the carbon dioxide cleaning solution and facilitate holding water to the stained area, thus facilitating cleaning of the stained area during the cleaning cycle.
When the surfactant comprises a CO
2
-philic group coupled to a lipophilic segment, the pretreatment composition is particularly useful for grease, oily stains and the like (e.g., hydrophobic stains). When the surfactant comprises a CO
2
-philic group coupled to a hydrophilic segment, the pretreatment composition is particularly useful for protein and tanin-type stains and the like (e.g., hydrophilic stains).
In another embodiment of the invention, the pretreatment surfactant is a poly(ether-carbonate) copolymer. Again, when present, the pretreatment surfactant is preferably included in an amount of from 1, 2, or 3 percent to 5 or 10 percent by weight of the total formulation (the surfactant may be one or a combination of surfactants as described above).
Preferably, the cleaning composition comprises (or further comprises, in addition to the surfactants noted above) an organic co-solvent. Particularly preferred organic co-solvents are C12-C15 alkane co-solvents. When present, such organic co-solvents are preferably included in an amount of from 2, 30 or 40 percent to 70, 80 or 90 percent by volume.
In another embodiment, the pretreatment composition contains d-limonene, either alone or, more preferably, in combination with an organic co-solvent (particularly a C12-15 alkane co-solvent as above), and/or a surfactant as noted above. When present, the d-limonene is included in the pretreatment composition in an amount of from 5 or 10 percent to 30, 40 or 50 percent, by volume.
The balance of the pretreatment compositions described above may comprise water.
A particularly preferred pretreatment composition includes both an organic co-solvent as described above and d-limonene as described above. Such a composition optionally but preferably also includes a surfactant or surfactants as described above.
DETAILED DESCRIPTION OF THE INVENTION
The term “pretreatment” as used herein refers to contacting a pretreatment composition, typically a liquid, to a stained portion or particular region of an article to be cleaned so that the pretreatment composition is deposited on that portion or region in an amount effective to enhance subsequent cleaning of the article, and then continuing or initiating further dry cleaning of that article with the pretreatment composition deposited upon the article to be cleaned.
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 pretreated and cleaned by the methods 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.
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 5,683,473 to Jureller et al., the disclosures of which are incorporated by reference herein in their entirety.
1. Cleaning Compositions and Processes.
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 particula
Cauble, Jr. David F.
DeYoung James P.
McClain James B.
Storey-Laubach Bernadette
Micell Technologies, Inc.
Myers Bigel & Sibley & Sajovec
Webb Gregory E.
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