Textiles: spinning – twisting – and twining – Strand structure – Alternately twisted
Reexamination Certificate
2001-07-09
2004-04-20
Calvert, John J. (Department: 3765)
Textiles: spinning, twisting, and twining
Strand structure
Alternately twisted
C057S244000, C057S246000, C057S289000, C057S293000
Reexamination Certificate
active
06722117
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for producing, and a continuous process for making yarns, in which said yarns are manufactured by processing together a number of singles yarns in such a manner as to result in a final yarn which, when used to manufacture a carpet, floorcovering or textile article, will result in the article having the appearance of being made using a fully twisted face yarn. The present invention additionally relates to yarns made using such a continuous process.
2. Description of Related Art
As used herein, certain terms have the meanings ascribed to them as follows: The terms “thread” and “filament” are intended to connote single filament fibers, whereas “singles yarn”, “singles fiber” or “strand” is an assembly of two or more threads or filaments.
Undrawn, essentially unoriented, and partially oriented yarns (POY), melt-spun from thermoplastic polymers provide yarns which are described in the art as “flat”, i.e., the filament bundles are essentially linear, and have little shape retention ability or resilience towards deforming forces. As such, these yarns have little utility in the field of carpet manufacture without further processing to improve these properties. A number of processes have been developed over the years in the fiber and carpet industries to provide tufting yarns with increased resilience, bulk, etc., by so-called “down-stream processing” of these yarns. Such processes, which largely consist of physical treatments to the as-spun singles yarns and/or collections of singles yarns brought together to produce higher filament count yarn bundles include, but are not limited to, drawing, (single or multi-stage), texturing, crimping and twisting.
As well as providing yarns with improved physical properties, and carpet backing covering ability, such processes have also been used to provide yarns with a wide range of aesthetic effects. This may be done, for example, by carrying out any or all of the above processes utilising two or more singles yarns in which the said singles yarns differ one from another in terms of dyeability, color, tensile properties, polymer types, cross-sectional shape, denier, or any combination of these. Processes of this type can provide the carpet designer with yarns which may be tufted into backing materials to manufacture carpets of widely ranging design and appearance, which ability would be expected to provide the manufacturer with a commercial advantage in the market-place.
One physical treatment or process which can provide yarns with an aesthetic appearance of particular desirability to the carpet designer is twisting, where singles yarns, particularly of different colors or dyeability, are cable twisted about each other in a spiral fashion. In theory, such a process can be used to provide various degrees of twist interval in the final bundled yarn product, and thus be capable of providing the designer with a number of options for producing a variety of visual effects in the final tufted carpet. However, true cable twisting of carpet denier yarns is difficult, slow and expensive to achieve, and even if achieved, requires that additional materials and processes be used to provide yarns and carpets in which said twist remains stable and unaltered over a period of time.
In order to be able to apply such appearance changes economically to yarns, it would be very useful to have a process which imparts the appearance of true twist to the yarns, without performing an actual cable twist operation. The process would, for economic reasons, be a continuous process, taking a plurality of undrawn, essentially unoriented, or POY singles yarns all the way through to a final, apparent twist, yarn. It would also be preferable to dispense with the need for the use of additional materials or processes in this continuous process, whose sole purpose is to “lock” the applied twist appearance effect in place and maintain said twist over time either in the yarn and/or in the ultimate carpet application.
Various disclosures have been made of processes proposed for producing “apparent twist” in carpet yarn, i.e., an appearance of twist, without performing a true twist. None has been commercially successful, whether it be because of technical deficiencies or the inability to process the carpet yarn economically. Several of these are discussed briefly below.
EP 007 563, (Teijin Limited), describes a cut-pile carpet yarn with randomly alternating S and Z false twist, (counter-clockwise and clockwise respectively). Yarn is false twisted in a single direction, heat-set to partially adhere the fiber bundle at node points, and allowed to “detwist”. The last operation, due to the torque inherent in the twisted, heat-set yarn, results in the creation of alternate regions of S and Z twist in the final yarn. Heat-setting techniques, adding an additional step to the process, is required in order to stabilise the shape of the final yarn.
U.S. Pat. No. 3,775,955, (Bigelow-Sanford Inc.), claims an apparatus for the creation of a stable twisted yarn product in which individual singles yarns are simultaneously air-jet spun and twisted, and then combined by entanglement. Use of entanglement as a final process along the total length of the yarn does not result in the appearance effect desired in the present invention.
U.S. Pat. No. 4,051,660, (Akzona Inc.), describes a yarn, and a process for its manufacture, in which two or more previously crimped singles yarns are air jet twisted about each other in totally random S and Z directions. The random twist is present in very short lengths, and does not result in sections of the final yarn having a cable-twisted appearance.
U.S. Pat. No. 4,219,998, (Platt Saco Lowell Ltd.), describes a fluid jet twisting device for twisting strand with alternating S and Z directions. The device has two fluid inlets, and a control system which allows formation of vortices within the device, which, it is claimed will impart alternating twist to a yarn passing therethrough. The device is a stand-alone apparatus, and it is nowhere suggested that it may be used as part of a continuous yarn process starting with undrawn or POY singles yarns, and ending with an apparent twist bundled yarn.
U.S. Pat. No. 4,215,530, (ASA S.A.), is concerned with a process and apparatus in which a POY yarn is subjected to a supplementary, simultaneous drawing and twisting operation. Twist is imparted by a double twist rotating spindle, such that the tension inherent in this part of the process causes the required drawing of the yarn. The yarn is then heat set in an additional process step.
Several patents have issued to E. I. DuPont de Nemours and Company, (U.S. Pat. Nos. 4,873,821; 4,977,739; 5,003,763; 5,012,636; 5,179,827; 5,228,282; 5,465,566; 5,557,915; 5,577,376; 5,598,649; 5,644,909 and 5,829,241), on products, and apparatus and methods for their production, which feature alternate twist plied structures. In general these make alternate S and Z twist plied yarns from individual singles yarns by a process which includes the steps of tensioning the singles yarns as they move in a path through the process, twisting the individual yarns in either an S or Z direction, stopping the twisting operation, then bonding the ply twisted yarns at a node while applying twist, stopping the twisting operation, then repeating the procedure while twisting in the opposite direction. This constitutes a slow and mechanically complex procedure, and requires adhesive, melt, or ultrasonic bonding of the yarns to maintain the twisted configuration.
U.S. Pat. No. 4,949,440, (Belmont Textile Machinery Co., Inc.), describes a process and apparatus in which a previously plied yarn is entangled by an air jet, said air jet travelling with the yarn for a short distance within the entangling device such that the air impinges on only a short section of the yarn. Note that the plied yarn is supplied from a package, and is not passed to the entangling process from a twisting device set within a continuous process.
U.S. Pa
Belcher, Jr. Arnold L.
Rasnick, Jr. Lawrence E.
Calvert John J.
Hurley Shaun R
Kerins John C.
Miles & Stockbridge P.C.
Prisma Fibers Inc.
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