Damp cleansing wipe

Details Damp cleansing wipe Damp cleansing wipe

2001-10-29

2004-05-04

Cole, Elizabeth M. (Department: 1771)

Fabric (woven, knitted, or nonwoven textile or cloth, etc.)

Coated or impregnated woven, knit, or nonwoven fabric which...

Coating or impregnation functions biologically

C442S408000

Reexamination Certificate

active

06730621

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns low-cost, easily manufacturable disposable single use, substantially damp, cleansing articles.
2. The Related Art
Personal cleansing and conditioning products have traditionally been marketed in a variety of forms such as bar soaps, creams, lotions, and gels. These formulations have attempted to satisfy a number of criteria to be acceptable to consumers. These criteria include cleansing effectiveness, skin feel, skin mildness and lather volume. Ideal personal cleansers should gently cleanse the skin or hair, cause little or no irritation, and not leave the skin or hair overly dry after frequent use.
A series of granted and pending patent applications have been published by Procter & Gamble describing disposable personal cleansing products purportedly addressing many of the aforementioned functionality concerns. These products are substantially dry articles having deposited onto a woven or non-woven cloth a cleansing composition of surfactant, structurant, skin conditioning agent and other performance ingredients. The term “substantially dry” is defined in most of these documents as maximum 10%, but in some instances as high as 15% water. Particularly preferred levels are 5% or less. A commercial embodiment sold in the U.S. is Olay® Daily Facial Cleansing Cloths having water levels of 3-4% by weight of the total cloth article. The technology is described in the following patents.
U.S. Pat. No. 5,951,991 (Wagner et al.) focuses on providing the substrate with a conditioning emulsion separately impregnated from the lathering surfactant onto the cloth substrate. U.S. Pat. No. 5,980,931 (Fowler et al.) emphasizes impregnation of oil soluble conditioning agents. WO 99/55303 (Albacarys et al.) describes skin care actives formulated with the cleansing composition.
Manufacturing processes for these products are reported in U.S. Pat. Nos. 5,952,043 and 5,863,663, both to Mackey et al. These patents teach use of a continuous lipid phase with a high melting waxy material deposited onto the wipe substrate. The material is intended to be sufficiently brittle so as to be easily disrupted by low shear contact (e.g. during wiping of the skin) to readily release an internal skin conditioning phase, yet the material is required to be sufficiently tough to avoid premature release of the internal phase during the rigors of processing. A problem with this technology is that through compromise the continuous external lipid phase/internal polar phase is neither sufficiently robust for processing and handling nor sufficiently releasable under wash conditions to allow efficient release of conditioning agent onto the skin.
More recent publications in this area include WO 01/08542 A1 (Cen et al.), WO 01/08655 A1 (Phipps et al.), WO 01/08656 A1 (Smith et al.), WO 01/08657 A1 (Lorenzi et al.) and WO 01/08658 A1 (Cawkwell et al.), all to Procter and Gamble. These documents extend the wipe technology to bonded double layer substrates of contrasting textural properties. A rougher of the two sides may act as a gripping surface while the other may be used for delivering cleansing aids. The articles are described as being substantially dry defined as a Moisture Retention ratio of less than 0.95 gms. The ratio reports weight for total non-bound liquids in the article but is not synonymous with water content. Water levels are not defined.
Our evaluations of dry wipes produced by the known technology has indicated slow latherability. We attribute the problem to the relatively thick coating deposited onto the wipe substrate. Another probable source of the problem is the relatively low water content. A need exists for a cleansing wipe of improved foamability and one which can be efficiently manufactured.
Accordingly, it is an object of the present invention to provide a disposable, cleansing product which upon contact with water rapidly lathers and generates a rich long lasting foam.
Another object of the present invention is to provide a disposable cleansing product having a cleansing composition coatable onto a flexible wiping cloth in a process that minimizes foam generation during manufacture.
Still another object of the present invention is to provide a disposable cleansing product which may include an impregnated composition allowing for improved manufacturability, better aesthetics and increased latherability.
These and other objects of the present invention will become more apparent in light of the following summary and disclosure.
SUMMARY OF THE INVENTION
A substantially damp cleansing product is provided which includes:
(i) a water insoluble substrate; and
(ii) a cleansing composition impregnated onto the substrate including:
(a) at least one lathering surfactant present in an amount sufficient to foam;
(b) water; and
 wherein the water is present at greater than 15% by weight of the product, but no higher than about 40%, and the composition having a viscosity as measured on a Haake CV 20 Rheometer with 30 mm profiled parallel plates at 23° C. ranging from about 50 to about 300,000 cp.
DETAILED DESCRIPTION OF THE INVENTION
Now it has been discovered that there is a critical range of viscosity for the impregnated cleansing composition. Below a minimum viscosity, the composition foams poorly when the dry wipe is wetted with water by a consumer. Although not wishing to be bound by a theory, we believe the low viscosity compositions are readily washed away by water down the sink and unavailable for lathering. By contrast, a too high viscosity composition cannot be quickly activated with water for lathering by a consumer. There is a delay period.
Accordingly, the compositions of the present invention will have a viscosity ranging from about 50 to about 300,000 cp (centipoise). Thickness is measured on a Haake CV 20 Rheometer with 30 mm profiled parallel plates at 23° C. A preferred viscosity range is from about 100 to about 250,000 cp, more preferably from about 150 to about 100,000, even more preferably from about 200 to about 50,000 cp, and optimally from about 400 to about 10,000 cp.
Another important discovery is the criticality of water levels. Substantially dry articles are poor at instantaneously generating a foam. Lathering surfactant cannot easily be activated at levels below 15% water. Some substantial amount of water must be present to allow the lathering surfactants to exit more rapidly from the substrate creating a foam. Minimum levels should be greater than 15%, preferably at least about 20%, more preferably at least about 25% by weight of the total cleansing product. These damp levels of water have the further advantage of giving pliability to the fabric substrate. A softer, more pleasant feel results.
Too much water should not be present. Large amounts of water impart a soggy poor aesthetic feel to the product. Even more significant, water encourages microbial growth. Much higher levels of preservatives are necessary with high water systems. Preservatives are not just a cost issue. Some consumers are hypoallergic to certain types of preservatives. Preserved systems must continuously be monitored to ensure that microbes have not mutated into strain resistant forms. Thus, maximum levels should be no higher than about 40% and preferably no higher than about 35% by weight of the cleansing product.
An essential element of compositions according to the present invention is that of a lathering surfactant. By a “lathering surfactant” is meant a surfactant, which when combined with water and mechanically agitated generates a foam or lather. Preferably, these lathering surfactants should be mild, which means that they must provide sufficient cleansing or detersive benefits but not overly dry the skin or hair, and yet meet the lathering criteria described above.
The products of the present invention typically include at least one lathering surfactant in an amount from about 0.5% to about 60%, preferably from about 0.75% to about 40%, and more preferably from about 1% to about 20%, based on the weight of the impregnated compos

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