Textiles: weaving – Fabrics – Materials
Reexamination Certificate
2002-03-25
2003-05-13
Calvert, John J. (Department: 3765)
Textiles: weaving
Fabrics
Materials
C139S42600R, C139S42000D, C066S202000, C028S155000
Reexamination Certificate
active
06561230
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a weft knitted fabric and, particularly, to a weft knitted fabric having a dry touch, producing a soft feeling, showing excellent stretchability and elongation recovery, and giving an excellent comfortable feeling to the wearer.
BACKGROUND ART
Weft knitted fabrics having as principal components poly(ethylene terephthalate) (hereinafter referred to as PET) fibers or nylon fibers, that are synthetic fibers, have been widely used for outerwear and innerwear applications. A weft knitted fabric having a PET fiber as its principal component is excellent in wash-and-wear properties, dimensional stability and yellowing resistance. However, the knitted fabric has the following disadvantages. It has a stiff feeling, shows insufficient stretchability and poor drapability, and gives a less comfortable feeling to the wearer.
Furthermore, a weft knitted fabric having a nylon fiber as its principal component has a soft feeling but with a slimy feeling, and shows stretchability to some extent. However, the knitted fabric has the disadvantages that it has poor wash-and-wear properties, shows low dimensional stability and has decreased yellowing resistance.
On the other hand, as a knitted fabric for which a poly(trimethylene terephthalate) (hereinafter referred to as PTT) fiber yarn is used, Japanese Unexamined Patent Publication (Kokai) No. 11-12902 discloses a mixed knitted fabric prepared by mixed knitting a cellulose fiber yarn with a PTT fiber yarn. The technology disclosed in the patent publication aims at obtaining a knitted fabric that produces neither streaks nor shade bars, and relates to a process that comprises scouring and dyeing a mixed knitted fabric of a warp knitted fabric, a circular knitted fabric or a flat knitted fabric with a fluid-jet dyeing machine, and treating the knitted fabric with a finish agent.
Furthermore, Japanese Unexamined Patent Publication (Kokai) No. 11-200175 discloses a woven or knitted fabric formed from a PTT yarn and excellent in color developing properties. The patent publication discloses a process that comprises shrinking a single feeder knitted fabric by 5.8% in the warp direction during scouring, heat treating the resultant knitted fabric, dyeing the knitted fabric, and heat treating the dyed knitted fabric again.
However, any of the knitted fabrics disclosed by the above prior art has the problem that it has a stiff feeling, shows poor stretchability, and gives a less comfortable feeling to the wearer.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a weft knitted fabric excellent in wash-and-wear properties, dimensional stability and yellowing resistance, having a dry touch and a soft feeling, showing excellent stretchability (represented by an elongation under constant load in the weft direction in the present invention) and an excellent elongation recovery (represented by an elongation elastic modulus in the weft direction in the present invention), and providing an excellent comfortable feeling to the wearer.
Another object of the present invention is to provide a weft knitted fabric particularly suitable for outerwear applications.
A PTT fiber is excellent in wash-and-wear properties, dimensional stability and yellowing resistance, has a soft feeling derived from a low Young's modulus and a dry touch feeling, and shows an excellent elastic recovery. However, when a weft knitted fabric is produced from the PTT fiber by a conventional method, only a knitted fabric having a stiff feeling, showing a low stretchability and providing a less comfortable feeling to the wearer is obtained.
In order to make a weft knitted fabric prepared from a PTT fiber manifest a particularly soft feeling, a high stretchability and an excellent elongation recovery, the present inventors have intensively investigated the relationship between a feeling, stretchability, etc. and the fine structure of a yarn, the physical properties of the yarn, the knitted fabric structure, and changes in the knitted fabric structure in a knitting process and a dyeing and finishing process. As a result, they have found the following phenomenon specific to the PTT fiber. Knitting shrinkage caused by a yarn tension in a knitting process is relatively significantly produced. When the gray fabric is thermally shrunk in the dyeing and finishing process, the bulk density of the knitted fabric increases. Consequently, the knitted fabric has a stiff feeling, and shows a lowered stretchability.
For example, when a circular knitted fabric or flat knitted gray fabric is prepared by a process conventionally carried out on a PET yarn, etc. as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 11-12902 mentioned above, the knitting shrinkage becomes significant. As a result, the density of the gray fabric becomes excessively high. When the gray fabric is dyed and finished by a process conventionally carried out on a PET fiber, etc., a shrinkage of the gray fabric caused by heat treatment in the dyeing process, etc. makes the bulk density of the knitted fabric considerably high. As a result, the knitted fabric thus obtained has a stiff feeling, shows a low stretchability in the weft direction, and gives a significantly less comfortable feeling to the wearer.
The present inventors have paid attention to such problems specific to the PTT knitted fabric, and discovered that when the design of a gray fabric and the knitting conditions of the PTT knitted fabric, and dyeing and finishing conditions of the knitted fabric are made proper, the bulk density of the PTT knitted fabric thus obtained can be made to fall in a proper range, and that a weft knitted fabric having a soft feeling and excellent in stretchability and elongation recovery can be obtained. Moreover, the present inventors have made the following discovery: in order to make the knitted fabric give a comfortable feeling to the wearer it is important that the knitted fabric be easily elongated in the weft (wale) direction under a low stress, be excellent in elongation recovery and be easily deformed under a low stress in the shear direction in addition to the knitted fabric having a soft feeling.
For example, as the method disclosed in Japanese Unexamined Patent Publication (Kokai) No. 11-200175, when the knitted fabric is shrunk comparatively large in the warp direction by heat treatment of dyeing process, or the like, only a relatively slight reduction in width of the gray fabric takes place, and the knitted fabric thus obtained shows a considerably low stretchability in the weft direction. Moreover, although a weft knitted fabric in which a PET raw yarn is used particularly easily forms runs, the present inventors have found that the PTT weft knitted fabric can be made to show an unexpected effect of hardly forming runs even when the raw yarn is used by setting the elongation under constant load in the weft direction of the fabric in a specific range. The present invention has thus been achieved.
In addition, “runs” herein is also termed “ladderings,” and designates a phenomenon wherein a knitted loop is off the knitting construction, and the knit texture linearly gets out of shape in the warp (course) direction in the knitted fabric when a relatively large tension is applied to the knitted fabric in the weft (wale) direction.
That is, the present invention is as described below.
1. A weft knitted fabric comprising a PTT fiber yarn, and showing an elongation under constant load of from 80 to 250% in the weft direction determined by JIS L 1018 under a load of 19.6 N per 2.5 cm.
2. The weft knitted fabric described in the above item 1, wherein the elongation elastic modulus after elongation by 50% in the weft direction determined by JIS L 1018 is 80% or more.
3. The weft knitted fabric described in the above item 2, wherein the fabric weight per square meter is from 80 to 500 g/m
2
, and the bulk density is from 0.28 to 0.60 g/cm
3
.
4. The weft knitted fabric described in the above items 2 or 3, wherein the shear rigidity (G) by KES-FB is from 0.28
Ikeda Masataka
Yamazaki Hiroshi
Asahi Kasei Kabushiki Kaisha
Calvert John J.
Muromoto Jr. Robert H.
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