Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Reexamination Certificate
2002-03-25
2004-02-17
Marcantoni, Paul (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
C106S733000
Reexamination Certificate
active
06692565
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a composition and a method for preparing colored cement for use as mortars (such as thin set mortars and brick mortars), grouts, stuccos or pool plasters. More specifically, the invention relates to a cement composition comprising cement, water and inert filler wherein the inert filler comprises an effective amount of an inert filler that has been coated with a pigmented composition or dye. The pigment or dye coating must be permanently bonded to the inert filler or impart a superhydrophobic property to the inert filler. When the pigment or dye coating is permanently bonded to the inert filler it is preferred that the pigment or dye coating be chemically bonded to the inert filler such as by means of an epoxy or siloxane linkage. The application of the pigment or dye coating should be conducted at temperatures below 600° F., preferably below 500° F. When the pigment or dye coating imparts a superhydrophobic property to the inert filler, the coating should comprise submicron silica particles that have been treated for water repellency. Examples of superhydrophobic coatings are described in U.S. Pat. Nos. 5,890,907 and 3,592,679 that are incorporated herein by reference. The present invention also has the surprising benefit of being a safe and non-carcinogenic cement composition.
The addition of pigments or dyes to cement compositions is well known in the art. For example, U.S. Pat. No. 4,204,876 teaches a pigment containing thixotropic slurry that can be stored in drums for 6-12 months by a cement contractor and used in a batching system. Similarly U.S. Pat. Nos. 5,558,708 and 5,846,315 disclose a method, composition and system for preparing pigmented cement compositions employing an aqueous component that contains a pigment and a dry powdered component. Other methods for preparing colored or pigmented cement compositions are described in, U.S. Pat. Nos. 5,199,986, 3,667,976, 4,946,505, United Kingdom Patent No. 2,183,626, German Patent No. 3,709,909 and WO 92/12102 which are incorporated herein by reference.
The 3M company also sells a product known as COLORQUARTZ™ aggregate which consists of quartz particles that are ceramically coated by a process which permanently bonds inorganic pigments to the quartz particle. It is believed that these particles are prepared by firing, i.e. intense heating, at tempatures above 600° F. The particles are available in an S grade, which are spherical shaped particles and a T grade which are trowable particles. These ceramically coated quartz particles have a large particle size, typically around 12-70 mesh or larger. The ceramically coated granules can be added to cement compositions such as pool plasters or flooring compositions to provide specks of color throughout the pool or flooring. The ceramically coated granules are very expensive and fail to provide a uniform color to the cement composition.
Attempts have also been made to prepare a gray cement composition by employing a naturally occurring gray calcium carbonate product as an inert filler. These attempts have not proved acceptable because the naturally occurring gray calcium carbonate exhibits a very high sulfur content that may adversely affects the final properties of the cured product. Other attempts at preparing colored cement compositions have included crushing naturally occurring colored marble, such as a green marble, and using the crushed colored marble as the inert filler in the cement composition. This process is quite expensive, the colors and hues are limited and additional pigment may be required.
With the exception of the naturally occurring gray calcium carbonate and the crushed colored marble, all the aforementioned prior methods for preparing colored cement require the user to modify the well established methods for preparing cement compositions by either changing the components used in the composition or requiring the addition of extra components such as pigments. These changes often increase the expense and time required for a project and are meet with great resistance by the industry. The use of naturally occurring colored marble will added greatly to the expense of any project due to the shipping and handling costs associated with locating the marble and shipping the marble from the quarry to a job site which is often hundreds if not thousands of miles away from the quarry.
A further disadvantage of the prior methods for preparing colored cement is that the pigment used to prepare the colored cement is typically dispersed throughout the composition rather than attached to any of the main components in the composition. The mere dispersion of the pigment allows it to be easily leached while the cement is hydrating. In addition, the dispersion of pigments in cement compositions often resulted in color differences between batches due to variations in the mixing procedure, gauging water variation, or inaccurate weighing of the pigment. A further disadvantage of the free pigment in the system is that during application of the cement, the pigment tends to float to the surface of the cement composition, causing a non-uniform appearance.
A further disadvantage of the prior methods for making colored cement and non-colored cement is the employment of sand. It has recently been reported that raw, uncoated sand presents a health risk to humans. The primary health risk is from the inhalation of respirable silica dust that can cause silicosis. Silicosis is a pulmonary fibrosis, i.e. causes the development of scar tissue in lungs, which can be progressive and disabling to the point of causing death.
The International Agency for Research on Cancer (IRAC) 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.
Due to the health risks associated with the use of sand in cement compositions, it is an object of the present invention to provide a cement composition that significantly reduces the carcinogenic risk.
It is also an object of the present invention to provide a composition and method for preparing colored cement that does not substantially increase the cost of a cement composition.
It is a further object of the present invention to provide a composition and method for preparing colored cement that can be easily incorporated into existing methods of manufacturing.
It is an additional object of the present invention to provide a composition and method for preparing colored cement that can provide a final cured cement product that exhibits a more uniform and permanent color that is UV stable and chemically resistant.
It is a further object of the present invention to provide a composition that reduces unwanted efflorescence in pool plasters and increases stain resistance.
It is still a further object of the present invention to provide a method of preparing colored cement that prevents the cement workers from breathing and contacting free pigments that often contain toxic heavy metals.
SUMMARY OF THE INVENTION
These and other objects of the present invention are achieved by a composition comprising cement, water and inert filler wherein the inert filler comprises an effective amount of an inert filler that has been pigmented by dying the inert filler, chemically bonding a pigment to the inert filler or permanently coating a pigment onto the inert filler. In a preferred embodiment of the present invention the inert filler comprises colored aggregate, sand, calcium carbonate or any other inert object. An especially preferred pigmented inert filler is a commercial product known DEK ROK surface aggregates, available from Clifford W. Estes Co. of Lyndhurst, N.J. The DEK ROK product is believed to comprise sand, the grains of which are coated with much finer submicron particles that have been surface treated for water repellency as taught in U.S. Pat. No. 3,592,679. The submicron silica powders are available commercially under the trade name CABOSIL from the Cabot Corp. of Bos
Hollas Ernest D.
Johansen, Jr. Charles J.
C-Cure Corp.
Hedman & Costigan ,P.C.
Marcantoni Paul
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