Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Reexamination Certificate
1997-01-27
2001-01-30
Webman, Edward J. (Department: 1617)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Biocides; animal or insect repellents or attractants
C424S686000, C424S687000, C472S126000, C106S464000, C106S465000
Reexamination Certificate
active
06180128
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a non-carcinogenic substance for use in sand boxes, play sets and play areas. More specifically, the invention relates to the elimination of sand which is a known carcinogenic material from children's sand boxes, play sets and play areas and replacing the carcinogenic sand with calcium carbonate, calcium-magnesium carbonate or crushed limestone that is non-carcinogenic.
BACKGROUND OF THE INVENTION
Sand which is also known as play sand, silica, crystalline silica, ground silica and quartz has long been used the sand boxes and play areas of numerous day care centers, schools and homes throughout the world. Sand has also been used as a ground covering in play grounds to provide a protective and cushioning environment around the play apparatus such as swings and sliding boards.
It has recently been discovered that sand presents a health hazard to humans. The primary health risk is from the inhalation of respirable silica dust which can cause silicosis. Silicosis is a pulmonary fibrosis, i.e. causes the development of scar tissue in lungs, which can be progressive and disabling and even cause death.
The International Agency for Research on Cancer (IARC) has categorized sand as a Class 2A carcinogen. A Class 2A carcinogen is one in which there is limited evidence for carcinogenicity in humans and sufficient evidence for carcinogenicity in experimental animals.
An additional health threat associated with the use of sand in sand boxes and play areas occurs from the germs and diseases left behind by animals such as cats, racoons, opossums and other types of rodents which void or otherwise foul the sand when the play area is not in use.
Due to the health risks associated with continually exposing children to sand in sand boxes and other types of play areas, it is an object of the present invention to provide a material that can be used in sand boxes and other types of play areas that is not carcinogenic and that does not create substantial health risks to humans.
It is also a further object of the present invention to provide a material that can be used in sand boxes and other types of play areas that repels animals such as cats and rodents and thereby prevents the animals from depositing germs, bacteria, or other noisome matter in the sand box or play area.
It is an additional object of the present invention to provide a material that can be used in sand boxes and other types of play areas that can be molded or formed by the user of the play area into shapes such as castles.
SUMMARY OF THE INVENTION
These and other objects of the present invention are achieved by replacing the carcinogenic sand currently used in sand boxes and play areas with calcium carbonate, calcium-magnesium-carbonate or crushed limestone. Although the particle size of the calcium carbonate used in the present invention is not critical, it is preferred that the calcium carbonate have a particle size of about 5 to about 200 mesh, preferably about 20 to about 150 mesh and most preferably about a 25-50 mesh.
The calcium carbonate used in the present invention may contain other naturally occurring impurities such as iron oxide or aluminum oxide. These naturally occurring impurities generally occur in amounts less than ten weight percent of the total weight of the calcium carbonate and do not detract from the objectives of the present invention.
The calcium carbonate used in the present invention is commercially available from a number of sources such as Specialty Minerals, Inc. of Easton, Pa. under the tradename MARBLEWHITE, Franklin Limestone Company of Nashville, Tenn. under the “T” line of products, ECC America, Inc. of Sylacagua, Ala. under the tradename MICRO-WHITE, Georgia Marble Company of Kennesaw, Ga. under the “GAMMA” line of products and from J. M. Huber Corp. of Marble Falls, Tex. under the “HUBERCARB” line of products. The calcium-magnesium carbonate used in the present invention is commercially available from National Mineral Products of Salinas, Calif. under the tradename DOLOMITE.
The present invention may also comprise additional property enhancing additives such as an animal repellant to prevent animals such as cats, racoons, opossums and other rodents from entering the sandbox or play area and depositing germs, bacteria, or other noisome matter in the sandbox or play area. The animal repellents used in the present invention are commonly known in the industry such as those described in U.S. Pat. Nos. 5,554,377, 4,775,532, and 4,735,803 which are incorporated herein by reference. It is important that the animal repellant be a material that will not present a health hazard or be otherwise offensive to humans. The animal repellent may be sprayed or sprinkled onto the calcium carbonate or calcium magnesium carbonate in an amount that is effective to repel animals as described in U.S. Pat. Nos. 5,554,377, 4,775,532 and 4,735,803 which are incorporated herein by reference.
The present invention may further comprise about 0.1 percent to about 20 percent based upon the total weight of the calcium carbonate of a mold or forming means such as a clay, starch or cellulose. The mold or forming means will increase the adhesive and/or cohesive properties of the calcium carbonate to allow the user of the sand substitute to mold the sand substitute into shapes such as castles, blocks or walls. Some of the preferred mold or forming agents are cellulose ethers such as, methyl cellulose, hydroxyethyl cellulose, sodium carboxymethyl hydroxyethyl cellulose, animal glues, starches such as corn, wheat, or potato, alginates, polyvinyl alcohols, proteins, gums such as gum arabic, gum guar, locust bean gum and clays such as montmorillonite, kaolinite, hectorite, bentonite, kieselguhr, attapulgite and smectite and any combination of the foregoing.
The clays such as bentonite or attapulgite clay of the type commercially available from Engelhard Minerals Co., under the tradename ATTAGEL 40, are especially preferred mold or forming means because the addition of a small amount of water to the calcium carbonate and clay composition will produce a composition that can be readily molded into three dimensional shapes when wet or moist and can be easily returned to particulate matter when dry.
In a preferred embodiment, the present invention comprises a sandbox consisting essentially of a frame that encloses a specific area containing a non-carcinogenic sand substitute. The frame can be any shape such as a rectangle, square, circle, triangle or combination of the foregoing. The sand substitute consists essentially of calcium carbonate, and animal repellant and a forming means. Due to the physical properties of the calcium carbonate, such as the solubility, it is important to include to animal repellant and forming means to insure that the integrity or “sand like” properties of the non-carcinogenic sandbox material is maintained.
REFERENCES:
patent: Re. 32513 (1987-10-01), Seaber
patent: 5472712 (1995-12-01), Oshlack
patent: 064284A1 (1995-03-01), None
Atsumi et al, Antimicrobial sand AN 1995:459709, CAPLUS abstract, Mar. 1, 1995.
The Merck index, tenth edition, See 1628 citation for calcium carbonate, pp. 228-229, 1983.
Mariano et al, Modeling dough, US pat 5171766 (see enclosed citation and abstract, AN 92:103080 USPATFULL), Dec. 15, 1992.
Hollas Ernest D.
Johansen, Jr. Charles J.
C-Cure Corp.
Hedman, Gibson & Costigan, P.C.
Webman Edward J.
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