Patent Application
20160177480
The present invention is related to sheet building materials such as sheet material used as wraps and roof underlayment used in construction. In particular, the present invention is directed to an improved sheet material with a leno fabric structural element providing an aggressive surface grip.
There is usually at least one layer of protection between a roofing material and the roof frame comprising a roofing underlayment. In one of the most common practices, the underlayment comprises a sheet material that is attached to the roof deck and helps to attach the roofing material to the deck and also provides other advantages, such as improved strength, reinforcement, cushioning for the roof material and insulation.
There are many options for roofing underlayment materials including rubberized asphalt, organic materials, fiberglass, and synthetic materials. Asphalt underlayments are presently becoming less popular in favor of modern sheet materials that are often engineered composites in combinations and technical features to improve the properties in comparison to traditional asphalt. For example, many of these modern engineered sheet materials for roof underlayment use have anti-slip technology to protect the people who install the roof, as the underlayment can be exposed for up to six months while the roof gets built.
As the roof is installed, the underlayment helps the roof material or shingles comprising the final roof covering to lay flatter and prevent buckling, which helps to prevent blow-off of the roof covering material by wind. Once the roof is installed, the underlayment provides other protection between the roof material and the roof deck. For example, the underlayment acts as a weather barrier and helps prevent wind-driven rain or water from other sources from infiltrating under the shingles and causing damage to the roof structure or the inside of a building. With traditional shingles, the roofing underlayment protects all of the seams between the roof frame and the roofing material.
Roof underlayment should preferably reduce the chances for moisture and mold by allowing water vapor to escape from inside a building. Noxious gases should also be able to escape. For these reasons, many roof underlayment sheet materials are engineered to be breathable, while still being sufficient to prevent rain and wind damage and have adequate physical properties to prevent tearing, elongating, shrinking, breaking, or puncturing. The underlayment material must also remain durable for the expected life of the roof.
Recently, underlayment sheets comprising fabrics and polymer films have been devised and introduced to the roofing industry to overcome shortcomings of traditional asphalt underlayment. Such composite materials may be substantially lighter and longer-lasting. However, an ongoing need exists for these materials to be strong and affordable for low-end applications. Low-end applications, such as traditional single-family homes, are sometimes too cost sensitive to take advantage of the modern underlayment that are favorably engineering with respect to features, but more expensive to the consumer. Another ongoing need is for the modern underlayment material to be slip resistant while wet during that time that the underlayment is exposed during roof installation. The combination of being both technologically advances to provide slip resistance during installation while being affordable remains a challenge in the industry.
U.S. Pat. No. 8,091,310 to Jones et al. provides one example of a modern building material used as underlayment. Jones uses fabric strands of varying thickness combined with polymer film bonded together. The multilayer material provided by Jones is believed suitable for high-end uses but less flexible and suitable for low-end uses because of the complexity of requiring different thickness strands and a bonded polymer film layer.
Accordingly, an ongoing need exists for a modern building material for use as an underlayment that is lightweight, strong and provides anti-slip technology, while remaining affordable and flexible enough to be used in a variety of low-end and high-end applications.
The invention provides an improved sheet building material with woven leno fabric and methods of making the same. The improved material is manufactured in the form of a sheet material that is particularly useful as a roof underlayment material.
A first object of the invention is to use a leno weave in a building material to create a coarse or grated surface on the sheet material with an aggressive grip that gives a secure surface for a roofer to stand on during installation of a roof material after installation of the roof underlayment.
Another object is to create a surface on the building material that provides grip or antiskid properties even when wet or having water pouring over the surface of the material.
Another object is to provide a material with aggressive grip that is inexpensive to manufacture, while still being modern and lightweight and being suitable as a roof underlayment that gives grip to a roofer's shoes.
Another object of the invention is to provide a building material having a surface on at least one side thereof that can be installed with aggressive grip for a roofer to stand on, while the building material can also be combined with substrates that provide further improved properties.
Yet another object is to provide a building material particular useful as a roof underlayment with aggressive grip that can be woven in combination with a flat fabric.
Still another object is to provide a building material that improves grip on a surface of the material while also reinforcing and strengthening the structure of the material, whereby the material provides an excellent roof underlayment.
Another object is to provide a material that improves grip without need for a supplemental coating layer, special polymers, or high tensile strength carrier substances that increase the cost of manufacturing in order to maintain a building material that is suitable for cost sensitive applications such as single family housing.
Another object is to create a building material having a stable surface for use as a roof underlayment material by weaving a combination of flat weave and leno weave on the same fabric.
Another object of the invention and embodiments discussed herein is to provide a high end underlayment material with a leno weave material laminated to a flat fabric.
Another object is to provide an underlayment material for application to wood surfaces on a roof by laminating woven leno fabric to a non woven material suitable for attachment to a wood surface, while maintaining a surface on the material that provides an aggressive grip for the roofer.
Another object is to provide dimensional stability for building material comprised of a leno fabric and used in roof underlayment by including attachment of various films to the leno fabric such as biaxially oriented polypropylene (BOPP) film.
Another object of the invention is to provide a four layer roof underlayment material structure including a laminate of leno fabric and nonwoven material combined with a BOPP film using a heat seal layer.
Yet another advantage is to provide a building material used in roof underlayment with an aggressive grip that does not require bonded intersections points of a fabric and, therefore, can be manufactured at less expense.
And, still another object of the invention is to provide a building material used in roof underlayment having a surface with an aggressive grip using flat, thin and light tape yarns that minimize weight and thickness.
Further advantages and features of the building material with woven fabric and methods of making the same are explained in more detail in connection with the examples provided in the drawings.
Referring now to
The leno weave provides a strong and durable fabric. However, the material is strengthened further using a combination of a light leno weave of
In
In the exemplary construction of the fabric portion of the building material 10, there are 4.8 yarns per inch woven in the warp direction of the fabric. Meanwhile, there are 3 yarns per inch woven in the fill direction. Experimentation has determined that a warp yarn of 650 denier, or 1.8×73 mil in dimension, provides the features and benefits desirable for the leno weave of the fabric of the building material 10. The 650 denier warp yarn is woven with a similar dimension fill yarn such as 1050 denier, or 1.75×108 mil. The embodiment's fabric weight is about 0.81 ounce per square yard. The overall thickness and weight of the yarns are in both directions are nearly the same, preferably within 3% of each other, i.e. 1.8×73 mil warp versus 1.75×108 mil fill. This permits utilization of flat yarns and eliminates the requirement for yarns of significantly different thickness and eliminates any need for round yarn or monofilament in order to obtain the aggressive grip provided by the fabric of the building material 10.
As illustrated in
An exemplary substrate 22 for application to the building material 10 having a woven fabric herein is biaxially oriented polypropylene, known as BOPP. This polypropylene film is extruded and stretched in both the machine direction and across machine direction, which increases strength and clarity. BOPP works synergistically with the fabric material of the building material 10 because it can provide a smooth surface on one side of the building material that is useful for installation of the material as a roofing underlayment on wood. Further, BOPP does not add dramatically to the cost and labor involved in manufacture because BOPP is easy laminate onto the fabric material. Distributors or consumers also appreciate and sometimes desire building materials that are printed or coated for special applications or for branding. BOPP is easy to convert and to coat with other materials or to print on the surface provided thereby to give the required appearance and properties desired.
The substrate 22 is not limited to BOPP. Another desirable embodiment includes providing the leno weave fabric portion of the building material 10 in combination with a flat fabric as a substitute substrate material. There are alternative means for accomplishing this combination. In a first embodiment, the leno weave is mixed into the same fabric with a flat fabric weave by varying the weave of the sheet of fabric therein. For example, the woven fabric of the building material 10 may include alternating strips of leno weave and flat weave. This could be useful in reducing cost by varying materials or yarns, creating patterns or changing properties of the building material.
In a second embodiment, the leno weave building material 10 is laminated to a flat fabric material that substitutes for the substrate 22. In this embodiment the flat fabric provides a backing for the leno weave without reducing the aggressive grip providing by the leno material on the opposing side of the building material. The flat fabric can provide strength and reinforcement while maintaining the aggressive grip property of the leno weave of the building material 10. The flat fabric substrate 22 can also improve the bottom surface of the sheet material for installation on a roof deck by allowing the substrate attached to the building material to make consistent contact with the roof deck and remain flush, which is useful for certain wood decks and other applications.
The building material 10 combined with a substrate material can inexpensively provide a reinforced roof underlayment comprising four layers. A first layer of the underlayment comprises the flat weft yarns of the building material, while a second layer of the underlayment comprises the warp yarns. At least portions of the warp yarns are manufactured to the underlayment second layer having a leno weave. A third layer of the underlayment comprises a nonwoven material, or substrate, laminated to the first two layers of the woven fabric material, and a fourth layer of the underlayment may comprise a BOPP film, as an addition to the substrate, covering the woven fabric material of the first two layers as a heat seal layer. Alternative, depending on the purpose of the construction and the materials used, the fourth layer may comprise a heat seal layer or other material combined with the nonwoven material of the laminate layer through further lamination of other reinforcement means.
Other modern woven roof underlayment materials have improved grip of a surface by bonding intersection of the material to create lift. An advantage discovered in the solution of the present invention is that the building material 10 provides an aggressive grip that does not require bonded intersections points of a fabric and, therefore, can be manufactured at less expense. The leno weave fabric design is found to maintain structural stability after manufacture as a building material while retaining the raised course surface that provides grip. As a further advantage, the building material 10 is manufactured using standard yarns, further reducing costs. Rather than use varied yarns or exotic and expensive large yarns combined with thin yarns, the present building material can be manufactured using flat, thin and light tape yarns that minimize weight and thickness.
A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. For example, features of one or more implementations may be combined, deleted, modified, or supplemented to form further implementations. As yet another example, the substrates or leno woven fabric depicted in the figures do not require the particular order or structure shown to achieve desirable results. In addition, other steps may be provided, or steps may be eliminated, from the described methods for manufacturing the building material, and other components or substrates may be added to, or removed from, the described building material. Accordingly, other implementations are within the scope of the claims.
