Draperies are primarily designed for style and appearance, and are generally made from fabrics of various colors which are printed or in some other way carry a design or image. Digital printing is replacing traditional methods in the textile industry. The main drivers are the cost-efficiency, ability to personalize prints and flexibility. Traditional screen-printing is being replaced by digital textile printing solutions like thermal transfer or sublimation printing for shorter production runs and personalized prints that require multiple colors and detailed images. Thermal transfer or heat transfer printing is a method to impart a desired color or color pattern or image to a synthetic fabrics such as polyester, nylon and acrylic. Thermal transfer printing uses thermally responsive inks containing sublimable colorants that under the influence of heat sublime or vaporize onto the surface of the fabric, penetrate the fibers and be entrained therein or attach to the textile fiber. Heat transfer printing processes and materials are quite old and described in numerous publications, for example, U.S. Pat. No. 3,363,557 (Blake), U.S. Pat. No. 3,952,131 (Sideman), U.S. Pat. No. 4,139,343 (Steiner), U.S. Pat. No. 6,036,808 (Shaw-Klein et al.), U.S. Pat. No. 8,628,185 (Hale et al.), U.S. Pat. No. 9,315,682 (Delys et al.), U.S. Pat. No. 4,117,699 (Renaut), U.S. Pat. No. 4,097,230 (Sandhu), U.S. Pat. No. 4,576,610 (Donenfeld), U.S. Pat. No. 5,668,081 (Simpson et al.), and U.S. Pat. No. 7,153,626 (Foster et al.).
In accordance with such imaging technology, a color pattern (discontinuous or image) to be imparted to a fabric substrate such as a woven, unwoven, or knitted material, is preprinted on a substrate (usually paper or a sheet of non-textile material) referred to as the transfer sheet or transfer donor element, as a print or image with an ink that contains the sublimable colorant. The inks used for preparing the printed pattern contain colorants that are selected to sublime at a temperature that does not compromise the integrity of the fabric or textile substrate. The inks can be applied to an inert, transfer donor support, conventionally paper, by any number of printing processes known in the art, including gravure, flexography, flat screen, rotary screen, electrophotography, and ink jet printing. The preprinted transfer donor element and the fabric to be printed are brought into contact under controlled conditions of time, temperature and pressure such that the colorant of the image is sublimed and transferred from the transfer donor element to the fabric substrate that must be of such a nature that it will receive and retain the transferred inks. to provide a permanent print or image thereon. Since the colorant becomes part of the structure of the material, the images on the fabric are vivid, resistant to fading or deteriorating after multiple washings and show good crock resistance. In addition, the fabric substrate must be resilient to the heat and pressure required for image transfer from volatilization or sublimation of the respective inks that are condensed on and are absorbed by at least the outer surface layers of the individual fibers of the fabric substrate. This effect can readily be obtained on many fabrics made from synthetic fibers, especially polyester fibers and polyester blends with natural fibers.
For example, U.S. Pat. No. 4,139,343 (noted above) discloses transfer sheets for heat transfer printing polyester textiles in yellow hues, inks that are useful in making such transfer sheets, an improved process for heat transfer printing polyester textiles and the printed or dyed fabrics thereby produced.
The art has recognized the difficulty of transferring images to fabrics made from either naturally-occurring or synthetic fibers. particularly fabrics comprising cotton. as described for example in U.S. Pat. No. 4,576,610 (noted above), in which a sublimable composition is formulated with a polyester bonding resin in which the polymer has a substantial amount of free carboxyl groups to markedly improve the depth, evenness and fastness of colors imparted by sublimation dye techniques to cotton and other naturally-occurring fibrous materials.
Draperies made from fabrics and printed as described above to create a desired visual effect are generally ineffective for preventing a substantial quantity of light penetration into a room from outside sources resulting in a corresponding undesirable level of illumination where light is not needed. To completely block undesired light, draperies generally consist of two separate elements: a decorative or printed face fabric, and a separate blackout material (or liner) attached to the decorative face fabric by sewing or other means. The blackout material or liner is typically turned towards a window or other light source in front of which the decorative face fabric hangs.
“Blackout” or light-blocking materials typically refer to articles that are substantially impermeable to light such as visible or UV radiation. When a blackout material is used to cover a window or other opening through which light can pass, it is designed to completely block out all external light from entering the room through that window or opening.
Blackout materials are desired by hotels and residences to ensure an ideal sleep environment, to protect the interior from ultraviolet light damage, and to provide privacy. Residential use of blackout materials is also desirable for those living in densely populated urban or suburban areas where the amount of light penetration into a window at night may be considerable due to sources such as street lights, light from adjacent buildings, and vehicle headlights. Hospitals may also use such materials to promote privacy and comfort for patients especially where multiple patients share the same areas.
Costs to fabricate light-blocking draperies (lined with a blackout material) are higher, compared to that of single-textile or unlined draperies, due to added expense of creating a blackout liner material and labor for attaching the blackout liner material to the face fabric. In addition, drapery fabricators must keep sufficient inventory of blackout liner material on hand. U.S. Pat. No. 5,741,582 (Leaderman et al.), suggests the possibility of imprinting, dyeing, or decorating a blackout architecture made up of material fabric on both sides of the drapery lining instead of the exposed foam thereby serving as a self-lined drapery fabric.
Blackout materials or liners are multi-layer structures, with a minimum of three separate coated layers. For example, U.S. Pat. No. 4,677,016 (Ferziger et al.) describes a light-blocking article comprising a fabric backed with a first coat of white acrylic foam, followed by a second coat of an acrylic foam having an opaque color, and finally, a third coat of white acrylic foam. U.S.
Patent Application Publication 2002/0122949 (Richards), describes a light-blocking article as a laminated structure comprised of two layers of fabric, two layers of foam, and a metalized plastic sheet.
These multi-layer blackout liners are sufficiently impermeable to light but unsuitable for thermal transfer printing. They are prone to substantial off-gassing thereby producing unacceptable levels of noxious fumes at the temperatures required to sublime and transfer sublimable colorants. High temperatures may also cause multi-layer blackout materials to suffer delamination or loss of adhesion between layers. Poor image quality due to incomplete and inconsistent transfer of the sublimable inks from donor elements to multi-layer blackout liners is commonly reported. Such problems can arise with multi-layer blackout liners known in the art even those that comprise polyester or another synthetic fabric including a blend, because of the continuous layer of sandwiched carbon black that can absorb heat and thereby act as a heat sink during the intended sublimation process. These unwanted effects could arise in metallized blackout curtains as well.
Thus, there is a need to provide blackout articles containing suitable colorant images or prints achieved using thermal transfer chemistries and processes that avoid these problems.