Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
2001-12-21
2004-02-10
Lo, Weilun (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
Reexamination Certificate
active
06689932
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the use of compositions that are stable on the body-facing materials of disposable absorbent articles, such as diapers, training pants, adult incontinence products, underpants, feminine care products, nursing pads, wound dressings and similar articles having absorbent capacity. Unexpectedly, the compositions are stable despite not including immobilizing agents previously believed necessary for stability on the body-facing materials. Consequently, the compositions are also simplified, i.e. contain fewer ingredients, from previously known compositions. The viscosity, hardness and overall stability of the simplified compositions were unexpected based on previously taken approaches to delivering a composition from a body-facing material of an absorbent article.
Absorbent articles such as diapers, training pants, incontinence products and feminine care products are worn such that they are in direct contact with the skin of the wearer. An unavoidable consequence of the use of absorbent articles is that the skin is exposed more directly to various physical and biological insults. Consequently, the barrier function of the skin covered by the absorbent article is put at risk. In order to provide disposability, absorbent articles are primarily constructed of nonwoven materials. Even though nonwoven materials are engineered to have soft hand and drape, they rub against the skin and there is friction. Such friction constitutes one form of physical insult to the skin barrier. Friction against the skin barrier also occurs with the use of absorbent tissues and wipes. Absorbent tissue and wipe products are frequently used for cleansing the skin areas covered by absorbent articles. Absorbent tissue and wipe products are necessary for removing biological waste materials from the skin.
In addition to these physical insults, skin covered by absorbent articles is also frequently exposed to biological insults. Biological fluids, such as urine, feces, vaginal secretions and nasal secretions, may contain a variety of components that can damage the skin barrier. Examples of these components include proteases, lipases and bile acids. Once the skin barrier is compromised, these components, in addition to other constituents of biological fluids, can initiate or exacerbate inflammation of the skin. As a result of the physical and chemical insults that skin covered by absorbent articles must endure, substantial work has been done to deliver compositions to the skin from the absorbent articles. Desirably, the compositions preserve the skin's own barrier function. However, the compositions can also repair or restore barrier function to skin that has been damaged.
Disposable absorbent articles such as diapers, training pants, adult incontinence products, underpants, feminine care products and nursing pads have been used to absorb body fluids and leave the skin dry. Disposable absorbent articles of this type generally include a liquid impermeable backsheet member, an absorbent core or assembly, and a liquid permeable body facing or liner material. The body facing or liner material comes into contact with the wearer's skin. While the body facing material is made of a soft, compliant material, the material rubs against the skin during use and may not leave the skin completely dry and free of the bodily fluids, such as solid or semi-solid waste, the absorbent article is trying to absorb. During frequent insults of bodily fluids and frequent use of disposable absorbent articles, the skin can become irritated and appear red and be sore to the touch.
Substantial efforts have been made to provide skin care compositions on the bodyfacing surfaces of disposable absorbent articles. The efforts have focused on providing skin care compositions on the bodyside liners of such articles because the bodyside liner typically has the greatest surface area coming into contact with the skin of the wearer of the article. Frequently, the benefits perceived to be obtained from the skin care compositions are only realized if the skin care composition is transferred to the skin of the wearer of the article. Hence, the desire to apply the compositions to the portion of the article having the greatest area of contact with the skin. It is also known to provide skin care compositions on the containment flaps, leg elastics, waist elastics and other portions of absorbent articles that come into direct contact with the wearer's skin.
Application of skin care compositions to absorbent articles has been known since the early 1970s. In the 1990s, efforts shifted to describing compositions that would remain where they were originally applied and that would not migrate to other portions of the article. U.S. Pat. No. 5,643,588 (issued on Jul. 1, 1997 to Roe et al.) describes a disposable diaper having a lotion coating on the topsheet of the diaper. The lotion coating is described as including an emollient and an immobilizing agent; the immobilizing agent prevents the flow or migration of the emollient into the diaper. The emollient is described as including petroleum-based, fatty acid ester type, alkyl ethoxylate type, fatty acid ester ethoxylates, fatty alcohol type, polysiloxane type or mixtures of such emollients. Suitable immobilizing agents are described as including C
14
-C
22
fatty alcohols, C
12
-C
22
fatty acids, C
12
-C
22
fatty alcohol ethoxylates having an average degree of ethoxylation ranging from 2 to about 30, waxes and mixtures of such ingredients.
The Roe patent describes the emollient in the lotion coating as having a plastic or fluid consistency at 20 deg. C. and as tending to flow or migrate into the interior of the diaper. Roe et al. describe that this migration of the emollient into the interior of the diaper can cause undesired effects on the absorbency of the diaper core due to the hydrophobic characteristics of many of the emollients. Roe et al also recognize that migration of the emollient in the lotion coating means that much more emollient has to be applied to the diaper topsheet. Increasing the quantity of emollient that must be applied not only increases the cost, but also exacerbates the undesirable effect on the absorbency of the diaper core. Roe et al. go on to recognize that the immobilizing agent counteracts this tendency of the emollient to migrate or flow by keeping the emollient primarily localized on the surface of the diaper topsheet.
Separate efforts have been made to identify compounds—distinct from those that could be considered “emollients” or “immobilizing agents”—capable of reducing lotion migration. U.S. Pat. No. 6,149,934 (issued to Krzysik et al. on Nov. 21, 2000) describes an absorbent article having a lotion formulation on the bodyside liner of the article where the lotion formulation includes an emollient, a wax and a viscosity enhancer. Krzysik et al. describe the viscosity enhancer component as helping to stabilize the formulation on the bodyfacing surface of the bodyside liner in order to reduce migration and to improve transfer to the skin. Krzysik et al. describe suitable viscosity enhancers as including polyolefin resins, lipophilic/oil thickeners, ethylene/vinyl acetate copolymers, polyethylene, silica, talc, colloidal silicone dioxide, zinc stearate, cetyl hydroxy ethyl cellulose, other modified celluloses and mixtures of such compounds.
The need for compositions that remain on and do not migrate away from the liner (and other bodyfacing surfaces) of absorbent articles has been well recognized. However, as work in the area of composition formulation continues, the compositions tend to increase in their complexity (for example, the number of ingredients). For a number of reasons, it would be beneficial to reduce the number of ingredients used in skin care compositions formulated for application to absorbent articles. Benefits include better quantification of individual ingredients in the blend, reduced handling and processing of individual ingredients and reduced cost associated with elimination of ingredients.
Cunningham Corey Thomas
Kottek Michael Brent
Kruchoski Benjamin Joseph
Krzysik Duane Gerard
Orchard, IV Lewis Preole
Dudkowski Alyssa A.
Kimberly--Clark Worldwide, Inc.
Lo Weilun
Webb Jamisue A.
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