Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Reexamination Certificate
1999-11-17
2003-12-16
Levy, Neil S. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Biocides; animal or insect repellents or attractants
C424S405000, C424S406000, C424S409000, C424S421000, C424S078310, C424S601000, C424S602000, C424S617000, C424S618000, C424S630000, C424S635000, C424S641000, C424S683000, C424S684000, C424S724000, C523S122000
Reexamination Certificate
active
06663877
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention is directed to solid surface materials having antibacterial properties.
2. Description of the Related Art
Artificial (or synthetic) marble can be considered as a general designation for various types of materials used as building products, such as bathroom vanity tops, sinks, shower stalls and kitchen counter tops, for example; furniture; sanitary use; lining materials; and stationary small articles. Also, from a viewpoint that the artificial marble is clean and neat, it has recently been used in hospitals, nursing homes, as well as commercial and residential food preparation facilities etc. Artificial marbles encompass cultured marble, onyx and solid surface materials typically comprising some kind of resin matrix and either with or without a filler present in the resin matrix. Typically, cultured marble consists of a gel coating of unfilled unsaturated polyester on a substrate of a filled unsaturated polyester, the filler generally being calcium carbonate, or the like. Onyx typically consists of a similar unfilled gel coat on a substrate of filled unsaturated polyester, the filler being alumina trihydrate (ATH). Solid surface materials are typically filled resin materials and, unlike cultured marble or onyx, do not have a gel coat. Corian® material available from E. I. du Pont de Nemours and Company, Wilmington, Del. (DuPont) is a solid surface material comprising an acrylic matrix filled with ATH.
As evidenced by the presence in the market of numerous materials for eliminating or minimizing human contact with bacteria, there is clearly a demand for materials and/or processes that either minimize or kill bacteria encountered in the environment. Such materials are useful in areas of food preparation or handling and in areas of personal hygiene, such as bathrooms. Similarly, there is a use for such antibacterial materials in hospitals and nursing homes where people with lowered resistance are especially vulnerable to bacteria.
Cultured marbles have been developed wherein an antibacterial agent has been incorporated in the gel coat, but not through the matrix of the substrate. Such materials have been disclosed in Japanese Patent Application Publication Kokai: 7-266522. However, such materials have a relatively thin gel coat, typically in the order of 15 mils and, as such, when the gel coat is depleted of antibacterial agent or the gel coat wears away or is otherwise removed, the antibacterial effect is significantly decreased or lost entirely.
With regard to solid surface materials consisting of either an unsaturated polyester resin or an epoxy resin there has not been any use of an antibacterial agent included throughout the resin.
SUMMARY OF THE INVENTION
This invention is directed to a solid surface material with an outer surface having a restorable antibacterial effectiveness. This solid surface material includes a matrix of at least one resin, at least one filler dispersed in the matrix, and at least one antibacterial agent dispersed in the matrix. The resin can be thermoset, thermoplastic, or combinations thereof. The antibacterial agent is present in an amount that provides an outer surface of the solid surface material with an antibacterial effectiveness within about 24 hours. The antibacterial agent can be an inorganic compound, an organic compound, or a combination thereof. It has been found that the outer surface has an antibacterial effectiveness which can diminish and that the antibacterial effectiveness can be restored by removing a portion the outer surface, preferably by abrading the outer surface.
The present invention also relates to a method for restoring the antibacterial effectiveness of a solid surface material of the present invention, wherein the solid surface material has an outer surface, at an initial time (t
0
), with an initial antibacterial activity value within 24 hours of sample incubation (&Dgr;
t0
@24 h) that is greater than zero, wherein at a first later time (t
1
), wherein t
1
>t
0
, the outer surface has a first later antibacterial activity value within 24 hours of sample incubation (&Dgr;
t1
@24 h) wherein (&Dgr;
t1
@24 h) is less than (&Dgr;
t0
@24 h), the method comprising: at a second later time (t
2
), wherein t
2
>t
1
, actively removing a portion of the outer surface of the solid surface material to provide a second outer surface on the solid surface material, the second outer surface having a second later antibacterial activity value within 24 hours of sample incubation (&Dgr;
t2
@24 h) such that it satisfies the Equation I below:
(&Dgr;
t2
@24 h)>0 and (&Dgr;
t2
@24 h)>(&Dgr;
t1
@24 h) Equation (I);
wherein the active removal step can be repeated whenever necessary to continuously restore the antibacterial effectiveness of the solid surface material.
In a preferred embodiment, the restoration method includes at least one active removal step, which can be achieve by abrading or ablating away the surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The artificial marbles of the present invention are made from a curable composition containing at least one antibacterial agent. The artificial marble materials of this invention are effective in inhibiting or destroying many common bacteria encountered in the home, and health care or food preparation environments. The term “antibacterial” is understood to be interchangeable with the term “antimicrobial” and other such like terms as would be familiar to one of ordinary skill. The term “antibacterial effectiveness” is intended to mean that, given a sufficient amount of antibacterial agent, the microbial concentration of a sample is decreased by at least about 30% over a period of time. It is known that the actual antibacterial effectiveness of an antibacterial agent depends upon the specific resin matrix used and the specific bacteria tested. The term “artificial marble” has been defined in the previous section. The term “solid surface materials” include those useful for decorative solid surfaces such as, for example, those used as building products, such as bathroom vanity tops, sinks, shower stalls and kitchen counter tops; furniture; sanitary use; lining materials; and articles such as office supplies.
The types of resin matrices useful in the present invention include both thermoplastic resins, thermoset resins and combinations thereof. Examples of thermoplastic resins include olefins, such as low and high density polyethylene and polypropylene; dienes, such as polybutadiene and Neoprene® elastomer; vinyl polymers, such as polystyrene, acrylics, and polyvinyl chloride; fluoropolymers, such as polytetrafluoroethylene; and heterochain polymers, such as polyamides, polyesters, polyurethanes, polyethers, polyacetals and polycarbonates. Examples of thermoset resins include phenolic resins, amino resins, unsaturated polyester resins, epoxy resins, polyurethanes and silicone polymers.
Epoxy resins useful in the present invention include those based on epoxide groups having certain reactivity. Such materials may include epoxy resins of bisphenol type A, bisphenol type F, phenol novolak type, alicyclic epoxy, halogenated epoxy, and cycloaliphatic epoxy resins.
Unsaturated polyester resins useful in the present invention include those wherein the reactivity is based on the presence of double or triple bonds in the carbon atoms. Unsaturated polyester resins are formed by the reaction of molar amounts of unsaturated and saturated dibasic acids or anhydrides with glycols. The unsaturation sites can then be used to cross-link the polyester chains, via vinyl containing monomers such as styrene, into a thermoset plastic state.
As is known to those of ordinary skill in the art, there can be many additives to epoxy or unsaturated polyesters. Typically, such materials are cured by adding cross-linking agents and catalysts to enhance the crosslinking action.
Acrylic resins useful in the present invention are not specially limited as long as it can be formed
Appleton Gerry Thorn
Gosser Nell Lynn
Vogel Bruce Neal
E. I. du Pont de Nemours and Company
Levy Neil S.
LandOfFree
Antibacterial solid surface materials with restorable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Antibacterial solid surface materials with restorable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Antibacterial solid surface materials with restorable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3106666