Textiles: spinning – twisting – and twining – Strand structure – Multifilament yarns
Reexamination Certificate
2001-11-05
2004-04-06
Calvert, John J. (Department: 3765)
Textiles: spinning, twisting, and twining
Strand structure
Multifilament yarns
C057S288000, C057S332000
Reexamination Certificate
active
06715276
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a false twist yam, a production method thereof, and a production apparatus thereof.
False twist yams of the invention have little cross sectional deformation, and have such features as good drape properties, soft feeling, bulky feeling, and lightweight feeling, as well as a desirable degree of stretch, strong-kneed, and repulsion feeling. A cloth comprising false twist yarns of the invention has mild luster that cannot be achieved with conventional yarns, and possesses a smooth, dry feeling.
BACKGROUND ART
With good mechanical and other properties, synthetic fibers have been used in goods in a large variety of fields including ordinary apparel.
Efforts in the field of apparel production have been made with the aim of providing improved synthetic fibers that are similar to natural material. Drawn yarns, in particular, tend to lack bulkiness, and to solve this problem, improved false twist yarns have been developed and manufactured in a process in which yarns are false-twisted while being drawn to achieve a desirable bulkiness.
To provide lightweight material, hollow fibers that consist of hollow single yarns have been developed and manufactured.
To provide fabrics having dry-feeling by reducing contact area between filaments, filament having a noncircular cross section of which the peripheral figure is wavy, have been manufactured. However, there are limits to being able to produce such a wavy form by a spinning process. If such filaments having noncircular cross section are false-twisted to produce false twist yarn, woven or knit fabric manufactured from the false twist yarns tends to have problems such as sandy touchable feeling or lack of soft feeling. In addition, the wavy form is deformed largely during the false twisting process, preventing the wavy form from having good effect on the resultant woven or knit fabrics.
False twist yarn produced by false twisting hollow filaments tend not to achieve required lightweight properties because of substantial destruction of hollow portions.
False twisting has to be performed at a high temperature to produce material that maintains sufficient bulkiness and crimp properties, but high-temperature processing tends to reduce the shrinkage percentage of the resultant false twist yarn.
JP 01-314740 A discloses a technique that aims to widen the range of the shrinkage percent level and reduce the cross sectional deformation of the resultant yarn. JP 01-183540 A discloses a technique that aims to produce high density woven fabric from a yarn having a small cross sectional deformation and a high shrinkage.
Under these techniques, however, filaments are false-twisted while being heated below the glass transition temperature, and therefore the techniques are low in productivity for false twist yarn and are not suited for commercial production.
In most conventional processes for out-drawing and false texturing or in-drawing and false texturing of synthetic fiber yarn, a twisted yarn is heated first, and then drawn, twisted, and heat-set, followed by untwisting.
In the conventional false twisting processes described above, a false twisting apparatus comprising a feed roller, a take-up roller, a heating plate provided between both rollers and a means of false twisting, is used.
If the false twist processing speed is increased in the false twisting apparatus, the twisting tension increases or the yarn is twisted on the heating plate, and an extension break of single filament in the yarn or a heat deterioration of the yarn that results in fluffing or scission of filaments is observed. It becomes necessary to extend the length of the heating plate to compensate for reducing the heat setting time.
To solve this problem, JP 09-20034 A proposes a method in which a yarn is entangled before being fed to a false twisting apparatus, and heated before being twisted by using a feed roller as a heating roller, followed by false twisting which is performed by using a nip roll as disclosed in JP 49-132353 A in such a manner that twisting starts at the end point of heating on the heating roller.
In this method, however, the starting point of twisting on the yarn is in contact with the surface of the heater, and the nip roll is used, which tends to cause problems such as heat deterioration and abrasion of the yarn on the surface of the heater, and wearing and deterioration of the nip roll which will result in retroaction of twist toward the heating roller and, in turn, fluffing and scission of the yarn. These problems can be very serious in the case of a yarn comprising ultra fine filaments or a synthetic fiber yarn comprising filaments having a special cross sectional shape.
Furthermore, a false twist yarn produced by the conventional process has a high crimp appearance property, and where a cloth is produced from such yarn, shrinkage of the yarn takes place at the time of appearance of crimps during the process of relaxation, presetting, denier reduction or dyeing, causing deterioration in drape properties, bulkiness, or soft feeling.
To solve these problems, the so-called “double-heating false twisting” process has been widely used, in which the yarn is false-twisted by the above-mentioned conventional technique, followed by further heat-setting of the resultant yarn using a heating plate.
Each of JP 59-130336 A and JP 60-252738 A discloses a technique in which an undrawn polyester yarn is false-twisted at a low temperature.
Each method, however, cannot solve the problem of the deterioration in drape properties, bulkiness, or soft feeling of fabrics due to shrinkage that takes place during the development of crimps.
In most conventional processes for production of synthetic fiber yarns, particularly drawn ones, a spindle-type winder is used to wind up the yarn in a pirn form on a bobbin in order to improve the pulling or rewinding properties of the yarn at the time of pulling out yarn from the bobbin to feed it to a twisting process or a weaving machine. In such a pirn-winding bobbin, a top pirn wind is formed at a top portion of the bobbin away from the pirn portion so that a location of the end of the yarn is found easily when using the bobbin.
When a top pirn wind is formed after winding up a false twist yarn in a pirn form, however, the yarn processing speed is decreased and the heat history of the yarn is affected during the formation of the top pirn wind, resulting in coexistence of yarns with different crimp properties. Thus, yarns with undesirable crimp properties have to be removed, causing a problem with the need of a complicated production process.
DISCLOSURE OF THE INVENTION
An object the present invention is to provide a false twist yarn that is free from the above-mentioned disadvantages of the conventional art, and is able to serve to produce woven fabrics or knit fabrics (hereinafter referred to as “woven/knit fabrics”) that have such features as good drape properties, soft feeling, bulkiness, and lightweight properties, as well as rich in stretch, kneed and repulsion feeling and can form cloth with mild luster and a smooth, dry feeling to achieve a feeling different from conventional drawn or false twist yarns, and a production method and a production apparatus therefor.
To accomplish that object, a false twist yarn of the invention consists of (i) a synthetic fiber yarn and has the following properties (ii)-(vii).
(ii) an elongation (EL) of not less than 20% and not more than 50%,
(iii) a crimp rigidity (CR) of not less than 10% and not more than 40%,
(iv) a crimp appearance stretch ratio (TR) of not less than 0.5% and not more than 15%,
(v) a dry heat shrinkage stress maximum value (MCS) of not less than 0.1 cN/dtex and not more than 1.0 cN/dtex,
(vi) a deformation degree of single filament (SDD) of not less than 1.0 and not more than 2.5, and
(vii) an entanglement number (EN) of not less than 4 and not more than 50.
It is preferable that the false twist yarn of the invention has a real twist number (RT) of not less than 4 t/m (turns/meter) and not more than 15 t/m.
It is preferable that eac
Matsuda Tatsuaki
Matsuki Sadao
Matsuoka Hiroshi
Nakazawa Genshin
Satou Kouichi
Calvert John J.
Hurley Shaun R
Piper Rudnick LLP
LandOfFree
False twist yarns and production method and production... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with False twist yarns and production method and production..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and False twist yarns and production method and production... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3252979