Patent Application
20090104408
The present disclosure relates to coatings containing aggregates and, more specifically, a polyurea coating containing aggregate.
Various coatings have been used to cover surfaces on roads, bridges, boat decks, floors, etc. to improve resistance to wear and deterioration. Typical surface coatings can include a resin-based binding medium comprising a two-part liquid polymer and hardener, which can be mixed and dispensed onto a concrete, metal or other support surfaces. One such coating is a polyurea that typically is a polyether-amines polyol elastomer. Polyurea resin-based binders have been used in combination with other reinforcing ingredients, such as aggregate, to provide an abrasion resistant coating for surfaces exposed to wear and traffic. Such products have been provided by pouring or spraying the polyurea onto a surface and broadcasting an aggregate onto the top of the polyurea coating. One characteristic of this type of polyurea coating is the rapid cure time of the coating, which is often under one minute. Such rapid cure times are often advantageous for resurfacing bridges and piers.
The present inventor has designed a coating having improved structural reinforcement and resistance to wearing.
According to one aspect of the present disclosure, a traffic bearing surface has a slow-set polyurea and an aggregate embedded throughout.
According to another aspect of the present disclosure, a coating includes a slow-set polyurea on a surface of a supporting structure. The slow-set polyurea forms a polyurea layer having a top surface, a middle portion, and a bottom surface with the bottom surface in contact with the surface of the supporting structure. An aggregate is substantially embedded between the top surface and the bottom surface and throughout the middle portion of the polyurea layer.
According to yet another aspect of the present disclosure, a method of forming a coating includes applying a slow-set polyurea layer onto a surface of a supporting structure and broadcasting an aggregate onto the polyurea layer. The broadcasted aggregate settles into the slow-set polyurea to embed the aggregate throughout the polyurea coating prior to a setting of the slow-set polyurea.
Further aspects of the present disclosure will be in part apparent and in part pointed out in the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating certain preferred embodiments, are intended for purposes of illustration only and are not intended to limit the scope of this disclosure.
Corresponding reference characters indicate corresponding elements throughout the several views of the drawings. The following description of exemplary embodiments is merely exemplary in nature and is not intended to limit the various embodiments of this disclosure, their applications, or their uses.
A method of forming a coating, according to one embodiment of this disclosure, includes applying a slow-set polyurea layer onto a surface of a supporting structure and broadcasting an aggregate onto the polyurea layer. The broadcasted aggregate settles into the slow-set polyurea to embed the aggregate throughout the polyurea coating prior to a setting of the slow-set polyurea.
Referring to
Referring again to
In some embodiments of this disclosure, the slow-set polyurea 22 is a resin-based product available under the name polyurea, available from Pacific Polymers International, Inc. of Garden Grove, Calif., or from Specialty Products Inc. of Lakewood, Wash. Other sources of polyurea 22 include members of the Polyurea Development Association (PDA), an international organization located in Kansas City, Mo., U.S.A. While slow-set polyurea compositions are generally known, the inventor hereof has developed a method of forming a coating and/or traffic bearing surface from the slow-set polyurea with an aggregate embedded throughout the polyurea that was heretofore unknown. As such, the coating produced in accordance with the principles of this disclosure has improved properties for coatings and traffic bearing surfaces.
The slow-set polyurea 22 typically has a cure time equal to or greater than one minute and preferably has a cure time in the range from one to twenty minutes. The selection of the polyurea 22 can be a function of its cure time. The desired cure time can be a function of a thickness of the applied polyurea layer; the composition of the aggregate 24; the temperatures of the polyurea, the supporting structure, and/or the ambient environment; the surface area for which the coating is to be applied; and the available resources for applying the aggregate to the polyurea. In one preferred embodiment, the cure time of the applied polyurea 22 is equal to or greater than five minutes. In another preferred embodiment, the cure time is equal to or greater than 10 minutes.
The slow-set polyurea polymer is generally prepared by pre-mixing each of the two parts of the polyurea 22 before combining and mixing the parts in pre-determined portions using a power mixer or other device that adequately mixes the two parts that comprises the final combination. The polyurea 22 can be heated to a temperature above the ambient temperature or can be combined and applied at the ambient temperature of the application or the temperature of the supporting structure 20. In some embodiments, heating of one or both parts of the polyurea mixture during pre-mixing provides improved application of the polyurea 22 to the supporting structure 20.
The slow-set polyurea 22 can be applied to a surface of the supporting structure 20 by pumping the resin and distributing the resin across the supporting structure 20 to obtain a desired predetermined wet-mil thickness for the polyurea 22 containing the aggregate 24. A variety of methods or devices for distributing the polyurea 22 can be used including a sprayer, a roller, a brush, a squeegee, or other spreading apparatus.
By way of example, to obtain a 250 millimeter (mils) or one-fourth (¼) inch coating, the slow-set polyurea 22 of about 125 to 150 mils coating can be applied to the surface of the supporting structure 20. The aggregate 24 is applied to the polyurea 22 and once embedded throughout the polyurea 22 results in a coating thickness of about 250 mils. The predetermined wet-mil thickness in one embodiment is in the range of about one-eighth (⅛) of an inch to about one-half (½) of an inch, but can alternatively be any thickness suitable for producing a uniform cross-section of aggregate within the coating. Such thickness can be a function of a size of the aggregate and the desired texture and structure of the fully embedded coating. Additionally, as discussed above a plurality of layers of the polyurea 22 and the aggregate 24 and/or a finish coat 30 provides for a total coating having various thicknesses.
The aggregate 24 can be any known aggregate material, including natural or synthetic materials. For example, the aggregate 24 can be rock, silica/sand, industrial byproducts, recycled products, glass, carbon, or metal. Additionally, other compounds or material can also be added to the polyurea and aggregate composition as desired for a particular coating application. For example, the coating can include fire retardants, accelerators, plasticizers, and coupling agents.
The coating can be formed by broadcasting an excess amount of the aggregate 24 across the top of the polyurea 22 while the polyurea is uncured. The aggregate 24 that has been broadcasted or distributed across the surface of the wet polyurea 22 is allowed to settle or is manually forced into the polyurea 22 to substantially embed into the middle portion of the polyurea 22, which envelopes and weeps around the many particles of the aggregate 24. However, often one or more “wet spots” can be visually identified on the top surface of the polyurea 22 and the aggregate 24. In such cases, additional aggregate 24 can be selectively applied or broadcast to portions of the top surface where these “wet spots” occur. The aggregate 24 can be broadcast in an excess amount across the surface of the polyurea 22 to the point of rejection from the polyurea 22 such that the polyurea surface no longer creates “wet spots.” In some embodiments, the aggregate 24 is throughout the polyurea 22 such as to provide a substantially uniform consistency of the aggregate 24 throughout the polyurea 22. The aggregate 24 can also be applied and forced into the polyurea 22 to provide for manual settling of the aggregate 24 throughout the polyurea 22.
The supporting structure 20 can be any type of structure including a concrete or asphalt surface on a road or bridge, or floor of a building, or can also comprise iron, steel, or masonite surface on the bridge, deck of a boat or pier. The supporting structure 20 can further include a traffic bearing surface such as a road surface, a bridge surface, a structural beam, a support structure, a parking deck, a road ramp, a walking ramp, a sidewalk, a driveway, a railway crossing, an airport runway, a pier, a masonite surface, a pool lining, a deck, a floor, and a patio. Additionally, the supporting structure 20 can be a first cured polyurea coating containing an aggregate and/or multiple layers of polyurea alone or in combination with an aggregate. The coating can be applied to any of a variety of surfaces for a broad range of applications and is not generally limited. The supporting structure 20 is preferably cleaned of any dirt, oil, water and other foreign debris before applying the first polyurea 22 of the coating to improve adherence of the coating to the supporting structure 20.
A coating can have multiple layers of polyurea 22. For example, in
In the exemplary embodiment of
A coating and/or traffic bearing surface according to the various embodiments of this disclosure provides for a uniform reinforced coating with improved wear and deterioration properties. The coating can be produced by applying a pre-determined wet-mil thickness of a slow-set polyurea elastomer to a surface. In some embodiments, the application of more than one layer can also provide optimum durability of the coating throughout the life of the coating as it wears down over long periods of use.
When introducing aspects of this disclosure or embodiments thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there can be additional elements other than the listed elements.
In view of the above, it will be seen that several aspects of this disclosure are achieved and other advantageous results attained. As various changes could be made in the above exemplary constructions and methods without departing from the scope of this disclosure, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
This application is a continuation of U.S. patent application Ser. No. 10/969,691 filed Oct. 20, 2004, the entire disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10969691 | Oct 2004 | US |
| Child | 12254477 | US |
