Patent Application
20140131228
The present disclosure is generally related to flexible silicone-based concrete and mortar materials for use in construction, such as in grout, mortar, concrete seal, and other applications. More particularly, the present disclosure relates to flexible silicone-based concrete and mortar materials that are resistant to breakdown in the presence of water.
A common, conventional construction material is concrete, and it is used in a variety of places due to its high strength as well as its wear and abrasion resistance. Over time, environmental conditions and use cause these construction materials to wear, abrade, crack or otherwise degrade, thus necessitating repair or replacement to restore them to their original condition. For example, concrete is at least partially permeable, allowing moisture to penetrate surface layers. In some instances, such penetration can lead to cracking and/or heaving of portions of the concrete.
Similarly, mortar is often used to seal gaps between tiles, stones, bricks, and other construction materials, in part, because mortar is durable. Unfortunately, like concrete, mortar is susceptible to moisture penetration and can breakdown over time due to exposure to the elements.
If the same or a similar material is utilized to patch holes or cracks in concrete or mortar, the patching material can shrink upon curing, disengage from the adjacent surfaces, and become dislodged. For this reason, specialty cement and concrete repair materials have been developed. For example, elastomeric forms, poured or injected thermoplastics and/or elastomeric fill materials have been used to patch cracks in concrete. The most common joint filler has been hot melt asphalt, which tends to fail over time due to hardening from aging or from temperature variations.
In an embodiment, a building material kit includes a first container to hold a silicone rubber base material, a second container to hold a curing agent; and a third container to hold a granular material. The silicone rubber base material, the curing agent, and the granular material are configured to be mixed to form a flexible building material.
In another embodiment, a method of forming a flexible building material includes adding a silicone rubber base material to a mixer in a quantity of 10 parts by weight and adding a curing agent to the mixer in a quantity of less than two parts by weight. The method further includes selectively adding a granular material to the mixer and mixing the silicone rubber base material, the curing agent, and the granular material to form a flexible building material. In an embodiment, a surface spray may be applied to a substrate prior to application of the flexible building material to assist in adhering the building material to the substrate.
In still another embodiment, a silicone mortar includes a silicone rubber base in a quantity of approximately ten parts by weight, a curing agent in a quantity of approximately one to three parts by weight, and a granular material in a quantity of at least one part by weight.
In the following discussion, the same reference numbers are used in the various embodiments to indicate the same or similar elements.
Examples of a silicone composition are described below that include a silicone base configured to vulcanize at room temperature, a catalyst, and granular material (such as stones, stone fragments, sand, powders or other particulates) that can be mixed to form a silicone composition. The silicone composition can be used as a flexible mortar or concrete material building material or can be applied to bond a building material to a substrate or structure of the same or different composition. The silicone composition can be used in a variety of construction applications, such as in securing stones to a fireplace structure, sealing gaps between bricks, filling between flagstones on a back porch or along the sides of a pool, or even in lieu of concrete. The silicone composition can also be used in in civil and industrial engineering projects, such as in repairing cracks and fractures in road surfaces, providing expansion joints between stones, and so on.
The silicone base and catalyst can be referred to as an addition cure or hydrosilylation cure, which involves the addition of a silicon hydride (SiH) to an unsaturated carbon-carbon bond in the presence of a noble metal catalyst (such as Platinum). The silicone rubber base includes a silicon hydride-functional crosslinker and an inhibitor to provide working time once the catalyst has been mixed with the base. This type of RTV silicone rubber produces no odors or byproducts. In particular, such silicone polymers do not have many extra groups to flash off. Accordingly, the composition is not exothermic and does not release odorants. Further, the silicone rubber composition is water resistant and maintains its hardness and tensile strength over a wide range of temperatures. Further, by selecting particulates for mixing with the silicone base material, color, texture, and compressibility of the compound may be controlled. In particular, the size of the particulates or granular material may be selected to increase hardness and reduce compressibility of the compound while maintaining some degree of flexibility. Additionally, the choice of silicone rubber and the ratio of the parts per weight of silicone rubber base relative to catalyst may be selected to provide a desired curing time and a desired hardness or durometer parameter. Different silicone rubbers may have different durometer/hardness readings and also possibly different ratios of curing agent and different cure times. Accordingly, the specific types of silicone rubber and catalyst may be selected by a user to produce a suitable building material for a particular environment.
Advancing to 104, a catalyst is added to the mixer. The catalyst may be any chemical mixture that, when combined with the silicone rubber base, produces a hydrosilylation cure. In an example, the catalyst includes a noble metal catalyst (such as Platinum). One possible example of a suitable catalyst is a Silastic® T-4/T-4 O Curing Agent that is commercially available from Dow Corning Corporation of Midland, Mich. Continuing to 106, a granular material may be selected from a plurality of granular materials. Such granular material may include sand, rocks, rock chips, concrete, or other material. Such granular material may be selected according to desired color, size, shape, or any combination thereof.
Moving to 108, the granular material is added to the mixer. Proceeding to 110, the silicone rubber base, the catalyst and the selected granular material are mixed to form a building material (or composition). In general, the silicone rubber base and the catalyst may cure to form a substantially transparent or clear building material. The granular material may be used to add texture, color or both to the building material, making it possible to substantially match the look and feel of the building material to surrounding materials, such as stones, bricks, concrete, or other materials.
In a particular example, the silicone rubber base and the catalyst may be mixed at a ratio of ten parts per weight of silicone rubber base to one-to-three part per weight of the catalyst (depending on the suitable or appropriate cure time, hardness, etc. and/or depending on the type of silicone rubber/catalyst admixture selected), with at least one part per weight of granular material added. The amount of granular material added may be selected to impart a suitable texture or appearance. In some instances, such as in a high traffic environment, more granular material may be added to provide a suitable texture and to reduce compressibility. In other examples, the parts per weight of the silicone rubber base and the catalyst may be adjusted. In particular, the ratio will change depending on the type of durometer silicone and curing agent used.
The resulting building material cures and hardens over a period of time, such as 24 to 48 hours. Once the material is mixed, a user may have between 30 minutes and 120 minutes to work the material onto the surface area being applied. During this time, the building material may be deployed as grout, placed between objects as a mortar and/or adhesive, or otherwise placed into use. Additionally, during this period, the user may press additional granular material into an exposed area of the building material to add texture to the material and/or to further match the building material to surrounding surfaces. Further, in some instances, the exposed area may be dusted with powdered material, such as concrete dust, sand, stone dust, chalk, and the like to soften the appearance of the material and/or to match or contrast with surrounding materials. One possible example of the building material used as a grout is described below with respect to
In general, building material 210 is a silicone rubber that remains substantially flexible over a range of temperatures, adheres to the underlayer 204 and to the flooring material 206 to provide a water resistant seal. Further, the silicone rubber resists mold and is resistant to ultraviolet light, providing a material that can be used in outdoor areas such as walkways, poolside areas, and so on.
While the example of
In some instances, prior to application of building material 210 to the structure 202, the structure 202 may be cleaned and the structure 202 may be treated with an adhesive to facilitate a bond between building material 210 and structure 202. In this instance, additional building material 210 may be added after the flooring material 206 is attached in order to fill spaces 208.
Building material 210 may provide a substantially clear finish that is glossier than adjacent surfaces. In such instances, it may be desirable to soften the appearance of the building material, such as by dusting or otherwise clouding the building material 210. One technique for clouding building material 210 may include thoroughly mixing sand, fine dust, or another colorant with the silicone rubber base and the catalyst. Another technique may include applying a layer of sand, fine dust, brick fragments, stone fragments, or colorant to an exposed surface of building material 210 before the cure process is complete. One possible example of a structure including such a coating is described below with respect to
Surface coating 402 may be selected to match adjacent flooring material or to contrast with adjacent flooring material. Surface coating 402 may include granules, rocks, glass beads, or other objects selected to provide a desired texture. Further, the durometer of surface coating 402 may be adjusted for a desired hardness. In an embodiment, surface coating 402 may be a paint or other colorant because latex and other paints will adhere to building material 210.
In some examples, flooring material 206 may be omitted, allowing building material 210 to be used as a coating. In one example, building material 210 may be used to coat a roof, for example, replacing shingles or other roofing materials. Small stones, rock dust, concrete dust, or other colorants may be embedded within or may be used as a coating 402 on such building material 210 to provide a desired appearance. In this instance, the building material 210 is thoroughly mixed with the desired colorant or granular material and, prior to completion of the curing process, building material 210 is spread substantially uniformly across a roof surface, providing a water proof, weather resistant, and appealing roofing material. Further, the building material 210 may be lighter than a standard roofing material, reducing the structural stresses caused by the weight of traditional roofing materials.
In another example where flooring material 206 is omitted, building material 210 may be used as a coating in lieu of stucco, paint, or other coatings. In particular, colorant may be mixed with the building material 210. Building material 210 may then be applied to exterior (or interior) walls of a structure, with varying thicknesses and/or varying directions-of-applications (e.g., swirls, straight lines, etc.) to provide a textured coating that is water resistant and resistant to deterioration in the presence of ultraviolet light. In a particular embodiment, taking advantage of the air-gap between wall surfaces of a wall, such as interior walls of a home, the coating may be applied on both sides of a wall in order to provide a sound damping function, reducing noise passage through interior and/or exterior walls of a structure.
While the examples of
In general, building material 210 secures bricks 504 to vertical substrate 502. Adhesive 304 may be omitted in some instances or may be used to enhance the bond between building material 210 and vertical substrate 502. Additionally, adhesive 304 may be applied to bricks 504 to enhance the bond between the bricks 504 and building material 210, as desired.
While the example of
Moving to 608, the building material is applied to the treated portions of the substrate. For example, if the substrate is a vertical surface, the building material may be spread onto the vertical surface to form a substantially uniform layer. Continuing to 610, a coating is optionally applied to an exposed surface of the building material. The exposed surface may be spaces between bricks or stones or may be an entire surface. The coating may include dust, granular particles, pebbles, stones, or even pigment or paint. Proceeding to 612, the building material is allowed time to cure.
For example, when used as a roadway patch, the building material may need cure time before allowing vehicles to drive over it. In some instances, such as when the building material is used to patch a pot hole, it may be desirable to clear the hole of loose debris, spray the adhesive, and then pour the building material into the hole. Depending on the size of the hole, some of the debris may be collected and mixed with the building material, both to provide a color match and to provide additional filler material that reduces the amount of silicone rubber needed to complete the repair. Such filler material may reduce the amount of cure time needed, in part, because the total volume of the silicone rubber is reduced.
When used to attach stones or bricks to a fireplace, a supporting structure may be used to hold the bricks for a period of time until the building material is cured. When used to seal cracks in a pool or adjacent to areas that may be experience significant water exposure, it may be desirable to prevent water from contacting the building material until the cure process is complete.
Depending on the surface, small pebbles, pieces of glass, or other items may be pressed into the building material before the building material is completely cured. For example, such items can be used to form a mosaic and/or to provide texture to a walkway, for example.
In the examples provided above with respect to
While the above examples have focused on using dust, concrete, stones, brick fragments, stone fragments, glass pieces, beads, and other types of materials to alter the appearance and or texture, it is also possible to use fibers, such as fiberglass, to enhance the tensile strength and/or durability of the building material.
Generally, vulcanization or hardening may occur at ambient temperature and no special heating is required. Preferably, the building material should be applied when the ambient temperature is at or above 50 degrees Fahrenheit to facilitate vulcanization. At lower temperatures, the building material can still be applied; however, the curing process may take longer. While conventional elastomers use water in the formulation, the resulting materials tend to be susceptible to breakdown when exposed to water and sunlight. Accordingly, the composition described above uses an inorganic composition, which tends to be resistant to water penetration and ultraviolet light degradation.
In some formulations, gravel, stone fragments, or cement may be used in conjunction with the building material (for example as the granular additive or filler material). The inclusion of such granular material imparts hardness and wear and abrasion resistance to the building material as well as contributing to the aesthetics. Generally, cement has relatively low shrinkage and expansion properties. When used as an expansion joint material, the building material is more compressible than concrete, providing a barrier to water intrusion that might lead to frost heaves during the winter while allowing for expansion of the concrete during warmer seasons. In an example, the building material is relatively heat resistant and is sufficiently flexible to expand and shrink in response to the expansion properties of the adjacent materials without tearing.
In general, the granular material may be any material that can mix with the silicone rubber and the catalyst, including, but not limited to, sand, aggregate, glass, silica, talc, carbon black, pebbles, stones, brick dust or shavings, fiberglass, other fibers, and the like. Further, these materials can be used as desired either alone or in various combinations of one or more of these materials. The specific granule sizes of the filler and the optimum amount to use can be determined by routine testing.
Additionally, in some instances, the shape of the granules may be controlled, such as by selecting or producing rounded granules to reduce the possibility of tearing due to edge wear, particularly in high traffic areas where heavy equipment or machines (such as cars, airplanes, and the like) may add additional stress to the building material. In an example, river rocks may be selected to provide smooth adhesion surfaces with limited serrations to prevent undesired cutting or tearing of the building material that might undermine the water barrier properties and lead to premature failure of the building material for its intended purpose.
Further, in some instances, the sizes of the granules may be controlled. For example, larger granules may reduce overall compressibility of the building material. Regardless of the type or size of the granular material, the resulting building material has a number advantages over conventional concrete materials including higher deformability, higher elasticity and flexibility, greater resistance to water penetration, increased strength of cohesion, increased corrosion resistance, increased resistance to low and high temperature variation, and so on.
In an example, the building material may be packed into a building material kit including a first container having a silicone rubber base material, a second container including a curing agent, and a third container including a granular material. The silicone rubber base material, the curing agent, and the granular material are configured to be mixed to form a flexible building material. In some instances, at least one of the second container and third container are sized to fit within the first container. In an example, the building material composition cures to form a water impermeable seal having a tensile strength greater than approximately 6.5 MPa, a tear strength greater than approximately 27 N/mm, and a hardness of approximately 40 points. A different durometer silicone may be selected to yield a different hardness or softness and to provide different tensile and tear strengths, depending on the intended application.
In conjunction with the methods and compositions described above with respect to
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the invention.
