Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Coated or impregnated woven – knit – or nonwoven fabric which... – Coating or impregnation functions biologically
Reexamination Certificate
2000-12-22
2004-09-21
Morris, Terrel (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
C106S015050, C106S031130
Reexamination Certificate
active
06794318
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to an indicator system that can detect the depletion of a variety of chemicals. More particularly, the present invention is directed to a visual indicator system that can be employed in use-dependent products to detect either the exhaustion or depletion of a chemical included therein. For example, the color indicator system of the present invention can be employed in food service wipers to detect the depletion of chemicals, such as anti-microbial agents.
BACKGROUND OF THE INVENTION
A use-dependent device or product is normally considered to be a product that becomes less effective over time. The decline in effectiveness of a particular use-dependent product can be caused by a variety of factors. One such factor that is significant in many applications is the depletion of an active chemical incorporated within the product. For example, wipers, such as those used in medical and food service applications, may contain an anti-microbial agent that is released during wiping to create a solution for disinfecting the surface being wiped. The anti-microbial agent helps prevent potentially harmful microorganism contamination when wiping a particular surface.
Typically, a user of a use-dependent product will want to know when the chemical within the product has been exhausted so that the user can discard the depleted product and begin to use a new one. If no such method is available for determining when the chemical has been exhausted, a user will unknowingly continue to use a product that has been rendered ineffective. For example, in the food service industry, it would be important to determine when an anti-microbial agent of a wiper has been exhausted so that it will not continue to be used thereafter.
In the past, various systems have been developed to indicate variables such as lapses in time, the presence of chemicals, or the absence of chemicals. For example, time indicators, such as disclosed in U.S. Pat. No. 5,699,326 to Haas et al., have been developed to communicate a lapse in time through the use of a visual change in color. Other time indicators are disclosed in U.S. Pat. No. 5,317,987 to Muller et al. and U.S. Pat. No. 4,248,597 to McNeely. In addition to indicators that reveal a lapse in time, indicator systems that detect the presence or absence of a chemical have also been developed. For example, U.S. Pat. No. 4,205,043 to Esch et al. discloses a system that employs a color-sensitive gas to detect the presence of chlorine dioxide.
Besides the above indicator systems, other indicators have been developed to detect the absence of a chemical within a use-dependent product, such as a sanitizing or anti-microbial wiper. For example, an anti-microbial wiper has been marketed by Pal International Inc. of England under the name WIPEX. According to the sales literature, this wiper contains an anti-microbial agent to sanitize various surfaces. In addition, the wipers include indicator stripes that are stated to fade gradually as the disinfectants are depleted. It is believed that U.S. Pat. No. 4,311,479 to Fenn et al. is related to this particular anti-microbial cloth. This indicator system, however undesirably reduces the hydrophilic nature of the wiper.
As such, a need currently exists for a more effective indicator system for use in use-dependent products. In particular, a need exists for an indicator system that can be incorporated into articles containing chemicals such as anti-microbial agents, without having a substantial adverse effect on the properties of the chemicals. Examples of such articles include anti-microbial and/or sanitizing wipers.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an improved use-dependent indicator system.
It is another object of the present invention to provide an indicator system that can signal the depletion of a chemical incorporated within an absorbent article.
Still another object of the present invention is to provide an indicator system that can signal the depletion of a chemical incorporated within an absorbent article without having a substantial adverse affect on the properties of the article that are provided by the chemical.
Yet another object of the present invention is to provide an indicator system containing at least one dye component.
Another object of the present invention is to provide an indicator system containing reactive and/or non-reactive dyes.
It is another object of the present invention to provide an indicator system containing a dye component(s) that can dissolve faster than an active chemical such that the dissolution of the dye can signal the impending exhaustion of the active chemical.
Still another object of the present invention is to provide an indicator system that contains a polymer mixture.
Yet another object of the present invention is to provide an indicator system that contains a polymer mixture that can retain its strength and adhesion properties after being applied to a web, and thereafter creped and cured.
Another object of the present invention is to provide an article in which less than 60% of one side of a cloth-like web is printed with the indicator system.
It is another object of the present invention to provide an indicator system that can provide sufficient control over the dissolution rates of the dye component(s) such that the system can effectively signal the depletion of the active chemical.
These and other objects of the present invention are achieved by providing an absorbent article such as a nonwoven web to which an indicator system of the present invention can be applied. An indicator system of the present invention generally includes at least one dye component and a polymer mixture.
In accordance with the present invention, any material commonly used in the art to manufacture cloths, such as wipers, can be used as the base web. In particular, a base web of the present invention is typically made from a nonwoven polymeric or paper-based web. More particularly, a base web of the present invention can be made from pulp fibers, synthetic fibers, thermomechanical pulp, or mixtures thereof such that the web has cloth-like properties. For instance, the base web can be made from softwood pulp fibers, such as Northern softwood kraft fibers, redwood fibers and pine fibers. Moreover, the base web can also include staple fibers, such as polyolefin fibers, polyester fibers, nylon fibers, polyvinyl acetate fibers, cotton fibers, rayon fibers, non-woody plant fibers, and mixtures thereof. In one embodiment, a base web of the present invention can also be webs that have been subjected to post treatment process such as hydroentanglement. In addition, the web can be a co-form material such as disclosed in U.S. Pat. No. 4,100,324 to Anderson et al. and U.S. Pat. No. 5,350,624 to Georger et al., which are incorporated herein in their entireties by reference thereto.
After forming the base web, an indicator system of the present invention can be applied. In general, the indicator system contains at least one dye component and a polymer mixture. Depending on the application, a single dye or combination of dyes can be used. In one embodiment, the indicator system includes a non-reactive dye, such as a foodstuff dye, that can dissolve out of an article to which it is applied. In other embodiments, the indicator system can include a reactive dye, such as a cationic dye, combined with a non-reactive dye. A reactive dye is typically permanent and will not dissolve out of the article. The combination of dyes selected generally depends on whether the article is desired to retain a color after the active chemical therein has been exhausted.
An absorbent article of the present invention also includes an active chemical, which is used for a variety of reasons. The active chemical can be applied to the article separately, or as part of an indicator system of the present invention. In one embodiment, the active chemical is incorporated within the indicator system as an anti-microbial agent used in wipers. In general
Anderson Ralph L.
Clark James W.
Radwanski Fred R.
Dority & Manning P.A.
Kimberly--Clark Worldwide, Inc.
Morris Terrel
Sperty Arden B.
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