Stock material or miscellaneous articles – Pile or nap type surface or component
Reexamination Certificate
2001-03-28
2004-05-25
Cole, Elizabeth M. (Department: 1771)
Stock material or miscellaneous articles
Pile or nap type surface or component
C428S095000, C442S186000, C442S270000, C442S402000, C028S107000, C028S109000, C028S206000
Reexamination Certificate
active
06740385
ABSTRACT:
This invention relates to tuftable fabrics and tufted products and, more particularly, primary carpet backings and tufted carpets.
BACKGROUND OF THE INVENTION
Most backings for carpets are fabrics woven from synthetic yarns. While many fabric constructions, yarn configurations and compositions have been used or described in published sources, woven polypropylene tape fabrics are preferred primary backings due to desirable properties that include tuftability, strength, mold resistance and cost.
For some applications, however, conventional backings have limitations. For example, although nonwoven polyester backings are typically more expensive than woven tape primary backings, polyester nonwovens are often favored for fine and intricate patterned, tufted broadloom carpets because even minor irregularities in the weave of woven backings can lead to pattern nonuniformity and mismatches when the backings are tufted. With growing emphasis on style and design in pattern-tufted carpets, demands on backings for regularity and stability will increase.
In woven primary backings, irregularities typically take the form of various deviations from weftline straightness. One such deviation, commonly referred to as “bow,” occurs when weft yarns are disposed in the shape of an arc, instead of straight, across the backing. Another, referred to as “skew,” occurs when weft yarns are not perpendicular to warp yarns but instead are diagonally offset or skewed across the fabric. When backings with bow or skew are tufted, misalignment of tufting needles with weft tapes may result and contribute to pattern distortion and mismatch. Random, isolated deviations from straightness in segments of a backing's weftline, or “blips,” can also occur and extra thickness of fabrics in selvage areas can cause deviations known as “hooking.”
For pattern-tufted broadloom carpets, resistance of both backings and tufted backings (also referred to as “greige goods”) to even small, in-plane deformations also is important for pattern uniformity. While traditional woven polypropylene tape backings have good resistance to deformations in the directions of their warpwise and weftwise axes, better stability of some nonwovens against off-axis deformations is an advantage when tufting fine and intricate patterns. With woven backings, shifting of the weave and nonuniform movement of backings as they advance through tufting can result in unacceptable bow, skew, other distortions, pattern mismatches and nonuniformity. When goods are not properly aligned during passage through finishing steps, such as dyeing, application and drying of backcoats, the tufted backings can skew if one side moves ahead of the other. Bow and skew can occur if greige goods experience different cross-machine direction tensions as they move through drying ovens, such as from dragging over rolls, nonuniform roll diameters, and roll misalignment. Irregularity also can result when greige goods are not stretched in the cross-machine direction sufficiently to maintain straightness of weft yarns.
It is known that needling, fusing or needling and fusing fibers or nonwoven fibrous webs or fabrics can improve dimensional stability and other properties of woven backings. The needled or fused fibers stabilize the weave against shifting. In addition, penetration of fibers through the weave as a result of needling and/or tufting can cause packing of fibers around tufts where they penetrate the backing, thereby contributing to stitch lock. The terms “calendar-lock weave” and “fiber-lock weave” (“CLW” and “FLW”) are well known in the carpet backing industry as designations for composites with fibers or nonwoven webs fused to woven backings, or fibers needled to woven backings, respectively.
U.S. Pat. No. 3,605,666 describes FLW composites having a woven backing fabric needled with a web or batt of selected, garneted staple fibers to provide a backing surface that is dye-compatible with carpet face yarn. In tufted carpets, the nonwoven layer is disposed on the pile side and said to improve appearance by hiding the woven fabric and reducing light reflection. The woven fabric is preferably woven from polypropylene filaments and the nonwoven is described as a thin but dense material, with preferred staple fiber lengths of 1-4 inches. The patent does not attribute improved dimensional stability to the needled nonwoven web, stating instead that the woven fabric provides substantially all of it in the disclosed products.
U.S. Pat. No. 4,053,668 describes manufacture of carpets by tufting a woven tape fabric that has been needled with a layer of staple fibers deposited onto it. The composites are described as having improved dimensional stability as a result of yarns in the weave being held against relative sliding by the needled fibers. Carpets made from the backings are tufted so that the needled layer is disposed on the back side of the tufted structure. The woven fabric is a woven polypropylene scrim with ribbon filaments; a 30×11 construction of 45 mils wide, 2.2 mils thick warp tapes and 90 mils wide, 3.6 mils thick weft tapes and weighing 3.3 ounces per square yard (“osy”) is preferred. Nylon staple fibers are preferred for dye-compatibility with face yarns, with lengths of 1.5-3 inches, deniers of 15-20, and an application rate of 5.5 osy.
Another composite backing described as providing improved dimensional stability and, specifically, resistance to bow and skew for improved pattern definition in printed carpets, is found in U.S. Pat. No. 4,069,361. The backings have a woven primary backing fabric to which is needled a 0.5-3 osy batt of staple fibers, which are then fused to form an integrated composite structure. The fabric is woven from polypropylene tapes or filaments. The batt is composed of staple fibers that can be fused without fusing or adversely affecting the woven fabric. Staple fibers composed of polypropylene are specifically disclosed.
Improved dimensional stability of needlepunched nonwovens composed of polypropylene staple fiber and fused at least at one surface, and use of the nonwovens in carpet backings, are also known from Canadian Patent 1,185,844.
U.S. Pat. No. 4,123,577 describes CLW primary backings having a woven polypropylene tape fabric to which is fused a nonwoven fabric composed of dyable fibers in combination with heat fusible fibers. The backings are characterized by improved dimensional stability, including stability for fine gauge tufting, and dye-compatibility of the fused layer with face yarns. Fusing the nonwoven to the woven is said to result in backings with higher tensile strength than FLW composites because needling the composite is avoided. Woven polypropylene tape primary backings and nonwoven fabrics composed of blends of nylon and polypropylene fibers are disclosed. Nonwoven fabric weights are about 3-70 g/m
2
(0.09-2 osy), with preferred weights as small as possible while providing desired dimensional stability and coverage to avoid grinning.
U.S. Pat. No. 4,140,071, noting difficulties with composites of woven backing fabrics needled with carded staple fiber webs of low basis weight, describes carpets made by tufting face yarn simultaneously through a woven polypropylene tape primary backing fabric and a bonded, lightweight nonwoven web of dyable continuous filaments. Improved tensile and tear strength are said to result from use of the bonded, continuous filament nonwoven, as compared to separate needling of the woven and nonwoven fabrics. Disclosed web weights are about 13-30 g/m
2
(about 0.4-0.9 osy). Improved dimensional stability of finished carpets is also said to result from tufting simultaneously through a woven or nonwoven backing fabric, such as a conventional primary backing, and a stronger, less stretchable open weave backing fabric, such as conventional secondary backing, according to U.S. Pat. No. 5,962,101.
U.S. Pat. No. 4,242,394 describes a three-component primary backing, said to have excellent dimensional stability, in which a woven polypropylene tape primary backing fabric and a woven, extruded
Baker Thomas Lee
Ceisel Stephen G.
Gardner Hugh Chester
Moon Richard C.
Oakley Thomas L.
BP Corporation North America Inc.
Cole Elizabeth M.
Hensley Stephen L.
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