Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Coated or impregnated woven – knit – or nonwoven fabric which... – Two or more non-extruded coatings or impregnations
Reexamination Certificate
1999-01-20
2001-02-27
Morris, Terrel (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Coated or impregnated woven, knit, or nonwoven fabric which...
Two or more non-extruded coatings or impregnations
C442S066000, C442S069000, C442S074000, C442S075000, C442S079000, C442S085000, C442S086000, C442S089000, C442S131000, C442S170000, C442S171000, C442S293000, C428S919000
Reexamination Certificate
active
06194329
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to a flexible urethane coated and/or laminated textile material for use particularly in the manufacture of rainflies for military tents, and for rainflies made from such material. More specifically, the invention relates to reversible lightweight urethane coated and/or laminated fabrics which meet predetermined levels of opacity, ultra-violet protection, flame retardancy, cold weather crack resistance, mildew resistance, abrasion resistance, and infra-red reflectance within specified wavelengths when either fabric side is facing outwardly, and for methods of making the fabric.
2. Description of the Prior Art
Rainflies are often used over the top of conventional-type tents to form what are commonly known as double-walled systems. Such flies are adapted to add protection from driving wind and/or rain for all the openings of the tent, in addition to providing supplemental shelter or storage space. Currently, members of the military are required to have several differently colored rainflies in order to provide inconspicuous shelter in different environments. (For purposes of this application, the term “color” is meant to encompass black and white as well as other traditional colors.) For example, military rainflies are generally available in camouflage, white for arctic conditions, green for tropical conditions, and tan for desert regions. In addition to providing protection from wind, such rainflies must be waterproof, flame-retardant, cold weather crack resistant, mildew resistant, abrasion resistant, meet a predetermined visual shade requirement, provide a high degree of visual opacity (i.e. ability to “black out” light from the interior of the tent) and provide a degree of infrared reflectance within specified wavelengths. Furthermore, because military personnel are often forced to transport their equipment, it is necessary that the weight of such rainflies be minimized. Several rain fly and tent fabrics are described in U.S. Pat. No. 4,594,286 to McKinney et al., U.S. Pat. No. 4833,006 to McKinney et al., and U.S. Pat. No. 4,308,882 to Pusch et al., the disclosures of which are incorporated herein by reference.
Prior art rainflies generally include a polyurethane coating which is either clear or colored to match the ground fabric. Other rainflies for use in arctic environments have been made using a black ground fabric in combination with a white coating, with the black ground fabric being designed to help provide the requisite opacity to the white structure. However, heretofore rainflies have only been designed to provide the requisite opacity, visual color and IR characteristics on a single side. As a result, military personnel are often required to be equipped with two or more such rainflies, when they are expected to encounter more than one environmental condition (e.g. where they are to be dispatched to a region having both snowy areas and woodsy areas.) Because it is generally desirable to minimize a soldier's load to the extent possible, having to carry more than one rainfly to anticipate and be able to respond to varying climactic conditions can add undesirably to the bulk and weight of a soldier's load.
Conventional one-sided fabrics generally utilize a ground fabric having a coated weight varying from about 2.5 to 4.5 oz per square yard. In such products, it is generally the coated side of the fabric which provides the requisite physical characteristics.
SUMMARY OF THE INVENTION
With the foregoing in mind, it is therefore an object of the present invention to provide a fabric which provides specific physical properties such as opacity and infrared (IR) characteristics on each of its two sides, to render it useful in military rainflies, and which has a different visual color on each of its two sides, so that it can provide inconspicuous shelter in two distinct environments.
It is also an object of the instant invention to provide methods for making such fabrics in an efficient and cost effective manner.
The process for producing fabric according to the instant invention involves the sequential application of several coating layers to a substrate. Although the substrate would generally be woven, it is contemplated that it could also be another type of textile substrate such as a knitted or non-woven material. The substrate is dyed to a first visual shade match using dyes specifically selected to provide a predetermined level of infrared reflectance within specified wave lengths. The substrate is desirably relatively lightweight (e.g., about 1.6-1.9 ounces) in order that the overall weight of the fabric is relatively low. A base coat compound is desirably applied to the substrate at a thickness of about 0.25 to about 0.5 mils. The base coat preferably consists essentially of a fire-retardant pigmented polyester polyurethane. This base coat is desirably applied from a solvent solution with a sufficiently high viscosity to prevent penetration to the opposite side of the fabric. The coating also desirably contains a pigment closely matching the ground shade of the substrate. The pigment volume concentration should be sufficiently high to prevent the ground shade from changing when applying the “opacifying” coat.
A mid-coat is then applied, preferably at a thickness on the order of about 0.5 to about 1.0 mils. The mid-coat desirably consists essentially of a fire-retardant pigmented polyester polyurethane similar to the base coat. This mid-coat contains a high concentration of “opacifying” pigment. This pigment can be an organic carbon black, an inorganic titanium dioxide, or a blend of organic and inorganic pigments blended to meet a specific color.
A third coating compound forming the top coat is then applied at about 0.5 to about 1.0 mils. This top coat desirably consists essentially of a fire-retardant pigmented polyester polyurethane. The top coat is preferably applied from a solvent solution and contains a pigment and flattening agent. This coating preferably provides a dry matte surface and contains enough of an appropriate pigment to meet specified spectral reflectance properties.
The coatings are desirably provided such that a maximum of 2.0 to 2.3 ounces per yard of coating are applied to the fabric, in order to minimize overall fabric weight. In addition, although three specific coats have been described, it is noted that a greater number of coats could be realized within the scope of the invention.
The coatings can be applied via floating knife, knife over roll or any coating machine capable of applying a specified thickness of each coating compound in a separate or continuous operation. The coating compounds also desirably contain compounding ingredients to provide the maximum flame-retardancy possible as well as any antioxidants, U.V. absorbers and biocides that may be necessary to meet desired specifications. In addition to achieving a fabric having superior resistance to environmental influences, the instant invention achieves a versatile product meeting specific infrared resistance requirements on each of the respective sides by providing visual shade matches for each side, superior cold crack resistance and improved resistance to humidity aging. As a result, the number of rainflies which military personnel can be required to possess can be reduced since the reversible fly provides the desired physical and visual characteristics on each of the two differently colored sides.
The rainfly is also desirably mildew resistant, cold crack resistant, flame resistant, has a high level of hydrostatic resistance, is water repellant, resistant to blocking, has good color fastness, has high tear and tensile strength, and is relatively low in weight. Where these features are not a function of the textile substrate or major coating components themselves, additives can be included in one or more of the coating layers to provide these characteristics. It is noted that the specific concentration and combination of such additives will vary depending on the particular specifications of
Boiardi Benito
Nelson Steve
Alston & Bird LLP
Brookwood Companies, Incorporated
Morris Terrel
Torres-Velazquez Norca L.
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