Technical Field
-
The present invention relates to a warp knitted
fabric stretchable in two directions.
Prior Art
-
A stretch woven fabric (knitted fabric) that is
elongated in the warp and weft directions is termed a
two-way stretch woven fabric (knitted fabric) (refer to
Table 1.74 on pages 139 to 140 of Handbook of Fiber
[edited by the Society of Fiber, second edition, Maruzen
Co., Ltd., Feb. 15, 1995] and to pages 41 to 49 in
"Fundamental Knowledge of Textile Products" edited by
Japan Fiber Control Society, Japan Clothing Control
Society, 1985). In particular, a warp knitted union
fabric of elastic yarns is generally termed a two-way
warp knitted fabric, and a warp knitted texture which is
formed by knitting a nylon fiber and an elastic fiber and
in which the elastic yarn forms a needle loop is often
used for shorts, lingerie, girdles and brassieres in
underwear applications, for swimwear, skiwear, skate
wear, diving wet suits and cycling pants in sports
applications, is used as coated and laminated fabrics in
outerwear applications such as jumpers. In general,
articles prepared from a two-way warp knitted fabric
material showing an elongation from about 100 to 300% in
the warp direction and an elongation from about 50 to
200% in the weft direction are used.
-
A warp knitted union fabric of nylon-elastic yarns
have the following disadvantages specific to a nylon
fiber. The knitted fabric tends to yellow when heat set
during dyeing or exposed to NOx gas during storage of the
products and the fabric is discolored when contacted with
chlorinated water because the fabric is dyed with an acid
dye. In order to overcome such disadvantages,
countermeasures such as those mentioned below are taken.
The knitted fabric is heat set at low temperature. The
fabric is completely closed packaged for the purpose of
preventing the final products from yellowing. A fixing
agent is used to prevent discoloration caused by
chlorinated water. Accordingly, it takes much labor to
treat and finish the products.
-
Production of a two-way warp knitted fabric has been
attempted, while avoiding the use of a nylon fiber that
is likely to yellow and likely to be discolored with
chlorinated water, by knitting of a polyethylene
terephthalate fiber and an elastic fiber. Although the
use of a polyethylene terephthalate fiber can prevent the
fiber from yellowing, the resultant fabric loses a soft
feeling that is characteristic of nylon fiber, and gives
a hard feeling. Even when the finished fabric density is
made coarse by conducting loose knitting in order to
obtain a knitted fabric that gives a soft feeling,
curling defects are formed. A knitted fabric giving a
soft feeling has never been obtained.
-
A polytrimethylene terephthalate fiber is known as a
polyester fiber that does not yellow, similarly to the
polyethylene terephthalate fiber, and has a low Young's
modulus.
-
A two-way warp knitted fabric formed with a
polytrimethylene terephthalate yarn particularly tends to
form fabric defects termed wavy edges (curls) at the
edges thereof. Occurrence of curls impairs the operation
efficiency during sewing, and sometimes makes sewing the
fabric impossible. When a fiber is knitted to form a
loop, a force that tends to bring the strain thus formed
back to a stabilized state is produced by the stiffness
of the yarn. A curl is formed when the stretch balance
between a force on the needle side of a single face warp
knitted fabric and a force on the sinker loop side is
lost. Although the curling can be reduced to zero by
making the knitted fabric density extremely high the
fabric then gives a hard feeling and is low in
stretchability. Moreover, there is another method
wherein the heat setting property of the yarn is
utilized, and the yarn is stabilized to suppress
occurrences of curls by heat setting the fabric at about
180°C. However, the heat setting property of a
polytrimethylene terephthalate fiber is not satisfactory,
and the stretch balance is lost even when the fabric is
heat set at temperature of 180°C or more because the
fabric easily stretches and shrinks; therefore, the
curling occurs.
Disclosure of the Invention
-
An object of the present invention is to provide a
two-way warp knitted fabric that solves the above
problems of a conventional two-way warp knitted fabric,
that does not yellow, that gives a soft feeling, and that
is substantially prevented from curling, by simple means.
-
The present inventors have discovered that the
present invention can be achieved by restricting the
number ratio of courses to wales in a warp knitted union
fabric formed with a polyester yarn composed of a
polytrimethylene terephthalate and an elastic yarn, and
the present invention has thus been achieved.
-
The present invention provides a two-way warp
knitted fabric with a warp knitted fabric construction
formed by knitting a polytrimethylene terephthalate yarn
as a front yarn and an elastic yarn as a back yarn, which
fabric has a knitted fabric density ratio from 1.55 to
2.35 calculated from the following formula (1):
knitted fabric density ratio = [(number of
courses)/2.54 cm]/[(number of wales)/2.54 cm]
-
The present invention will be explained in more
detail.
-
In the present invention, a polytrimethylene
terephthalate fiber designates a polyester fiber
comprising trimethylene terephthalate units as principal
repeating units. The polytrimethylene terephthalate
fiber contains about 50% or more by mole, preferably 70%
or more by mole, more preferably 80% or more by mole,
still more preferably 90% or more by mole of trimethylene
terephthalate units, and further contains in total, as
other remaining components, about 50% or less by mole,
preferably 30% or less by mole, more preferably 20% or
less by mole, still more preferably 10% or less by mole
of an acid component and/or a glycol component that will
be described later.
-
The polytrimethylene terephthalate fiber may take
the shape of either a filament yarn or a staple fiber.
The fiber may be uniform, or thick and thin in the
longitudinal direction. A filament of the fiber may have
a round-shaped, a triangle-shaped, a L-shaped, a T-shaped,
a Y-shaped, a W-shaped, an eight leaf-shaped, a
flat, a polygonal (e.g., dog bone-shaped), multi-leaf-shaped,
a hollow or an indefinitely shaped cross section.
However, for underwear, sports or outerwear applications,
the yarn preferably is a filament yarn that is uniform in
the longitudinal direction, and the filaments are
preferably not round. The single filament size can be
from 0.1 to 5.6 dtex in terms of single yarn denier. A
yarn thickness of about 33 to 110 dtex is suitable.
-
The shape of a polytrimethylene terephthalate-based
yarn to be knitted into a two-way warp knitted fabric can
be a spun yarn such as a ring spun yarn and an open-end
spun yarn, a multifilaments flat yarn (including an
extremely thin yarn), a soft twist yarn, a hard twist
yarn, a combined filaments yarn, a false twist yarn
(including a stretch false twist yarn), a fluid-jet
texturized yarn, and the like yarn. In addition, the
two-way warp knitted fabric of the present invention may
be made to include another yarn such as a natural yarn,
represented by wool, usually in an amount range of 30
mass% or less so long as the object of the present
invention is not impaired, by means such as a textile
blend (silo spun, silo fill, etc.), an interlaced
combination (a different shrinkage combined filaments
yarn with a high shrinkage yarn, etc.), a twisted
combination, a composite false twisting (elongation-differenced
false twisting, etc.), fluid-jet texturizing
with two feeds, and the like.
-
In the present invention, an elastic yarn to be
knitted with the polytrimethylene terephthalate-based
yarn can be an optional elastic yarn such as a
polyurethane-based yarn and a polyether ester-based yarn
showing an elastic stretchability of 100% or more in
terms of breaking elongation, and having a size of from
11 to 78 dtex, preferably 17 to 44 dtex. There is no
specific limitation on the polymer and spinning method so
long as the fiber is an ordinary polyurethane-based
elastic fiber.
-
The elastic fiber is preferably a fiber the
stretchability of which is not impaired in the presetting
step, during dyeing, usually at treating temperature near
190°C. The form of the elastic fiber is a bare yarn, a
covering yarn or a twisted yarn, but there is no specific
limitation.
-
The two-way warp knitted fabric according to the
present invention is a knitted fabric formed in a two-bar-fabric
construction that are composed of a closed lap
and/or an open lap obtained by threading polytrimethylene
terephthalate yarns through the front guide bar and
elastic yarns through the back guide bar on a single
needle bar warp knitting machine. Therefore, the two-way
warp knitted fabric according to the present invention is
formed with a fabric construction that can be knitted
with two bars. Typical examples of a usable fabric
construction include double denvy, double code, half
tricot stitch (lock knit), back half, queen's code, satin
and double atlas. The stretchability and curling
property of the two-way warp knitted fabric greatly
changes depending on the fabric construction. For
example, when the underlap of a front construction is one
needle interval or less, the fabric is thin and tends to
curl. When it is three needle interval or more, the
fabric is thick, gives a hard feeling, and shows lowered
stretchability. When the underlap of a back construction
is a zero needle interval, stretchability in the weft
direction cannot be obtained. When it is a two needle
interval or more, adjacent elastic yarns in the fabric
are melt bonded at contacted portions and cross portions
with a heat during dyeing, and the fabric gives a hard
feeling. Accordingly, in view of the selection of a
combination of the number of underlaps, satin and half
tricot stitch are preferred, and a half tricot stitch is
more preferred, though the fabric construction is not
restricted thereto.
-
Preferred knitted fabric constructions are
exemplified below without any intention of restriction.
- (1) Front bar two needle interval fabric
construction, namely, a knitted fabric that is a so-called
half tricot stitch:
front 10/23, and back: 12/10. - (2) Half tricot stitch obtained by shifting the
positional relationship between the front construction
and the back construction:
front: 10/23; and back: 10/12. - (3) A half tricot construction obtained by combined
deformation of an open lap and a closed lap:
front 10/23; and back 21/01. -
-
In the present invention, the ratio of the number of
courses to that of wales, the courses and wales forming a
unit surface area of a finished knitted fabric, namely,
the knit density ratio calculated from the formula (1) is
adjusted to 1.55 to 2.35. A soft feeling specific to a
polytriethylene terephthalate fiber is then maintained on
the knitted fabric surface, and a two-way warp knitted
fabric in which curls are suppressed is formed.
Knit density ratio = [(number of courses)/2.54
cm]/[(number of wales)/2.54 cm]
-
In the present invention, the knitted fabric density
ratio is a density ratio of a knitted fabric subsequent
to dyeing finishing, and a knitted fabric must be
designed while the shrinkage and the like of the knitted
fabric are taken into consideration when the fabric is to
be knitted. The number of loops per 2.54 cm is used for
the calculation of a knitted fabric density ratio, and
the ratio is defined as a value obtained by dividing a
density in the warp direction that is the number of
courses/2.54cm by a density in the weft direction that is
the number of wales/2.54cm.
-
When the knitted fabric density ratio is less than
1.55, curls tend to be formed in the right and left end
portions in the weft direction of the two-way warp
knitted fabric. Moreover, when the knitted fabric
density ratio is larger than 2.35, the curling tends to
occur in the upper and lower end portions in the warp
direction thereof. A preferred knitted fabric density
ratio is from 1.65 to 2.25.
-
The object of the present invention can basically be
achieved by designing the knitted fabric on the basis of
the knitted fabric density ratio of the invention even
when the gauge of the knitting machine changes. For
example, when the knitting machine is of 28 gauge, the
most preferable knitted fabric density ratio is from 1.56
to 1.93. When the knitting machine is of 36 gauge, the
most preferable knitted fabric density ratio is from 1.85
to 2.35. That is, when the gauge becomes finer, the most
preferable range of the knitted fabric density ratio
tends to become larger.
-
One example of the designing of a knitted fabric
that makes the knitted fabric density ratio of a two-way
warp knitted fabric from 1.55 to 2.35 will be explained
below. The runner length (also termed a run-in, and
being one index indicating a yarn length that forms one
stitch, the stitch becoming coarse when the numerical
value of the same texture becomes large, showing a yarn
length per 480 courses in the warp knitting technology)
of an elastic yarn during knitting, is made large in
comparison with the runner length in a knitted union
fabric of a nylon yarn or a polyethylene terephthalate
yarn, and an elastic yarn, and knitting must be carried
out while the course on the machine (being one index
showing the height of one stitch during knitting, and
representing a high knit fabric density when the number
of courses that is a wound amount of the knitted fabric
is large) is being made coarse. The runner length and
the course on the machine of a polytrimethylene
terephthalate yarn and an elastic yarn must be set in
such a manner that the two-way warp knitted fabric thus
formed has a given density ratio when subjected to the
following procedures: the fabric is relax scoured at 90°C
for 1 minute; the fabric is then preset so that the
density ratio becomes within that of the present
invention during tentering in the presetting step
subsequent to scouring; the fabric is finish set with
approximately the same density as the width and length
subsequent to dyeing or with the same density ratio as in
presetting.
-
Although a setting temperature from 150 to 200°C,
and a setting period of time from 30 to 60 sec can be
used, a preferred temperature is near 190°C during
presetting, and near 170°C during finish setting. The
resultant knitted fabric can be well set, and causes no
problem about color fastness. When the knitted fabric is
to be dyed, an optional dyeing machine can be used.
However, use of a liquid-jet dyeing machine is preferred
because uneven dyeing hardly even takes place.
-
The two-way warp knitted fabric of the present
invention can be knitted with a tricot knitting machine
or a raschel knitting machine, and there is no specific
limitation on the gauge of the knitting machine.
However, a knitting machine of 18 to 40 gauge/2.54 cm
should optionally be selected in accordance with the
thickness of a yarn to be used.
-
As explained above, a two-way warp knitted fabric
producing no curlings, giving a soft feeling, and causing
no problem about shrinkage such as washing shrinkage and
pressing shrinkage can be obtained through adjustment of
the knit density.
-
A two-way warp knitted fabric having a knitted
fabric density from 1.55 to 2.35 can be prepared from a
two-way warp knitted fabric with its front texture formed
with a nylon yarn and a polyethylene terephthalate yarn.
However, when a knitted fabric with its knitted fabric
density in the range of the present invention is
produced, the two-way warp knitted fabric, in which a
nylon yarn is used, is an unsatisfactory one having a
problem with yellowing. On the other hand, a knitted
fabric in which a polyethylene terephthalate yarn is used
alone gives a hard feeling. When a coarser knitted
fabric is prepared for the purpose of obtaining a fabric
giving a soft feeling, curls come out.
-
As explained above, the polytrimethylene
terephthalate fiber used in the present invention can
comprise, in addition to the repeating units of a
polytrimethylene terephthalate, a copolymer of
terephthalic acid or its functional derivative, and
trimethylene glycol or its functional derivative as
another acid component and/or a glycol component (as
third components). In the course of synthesis process of
copolymer, a copolymerized polyester may be formed by
adding suitable one, or two or more of third components.
Alternatively, such a polyester other than a
polytrimethylene terephthalate as polyethylene
terephthalate, a nylon and a polytrimethylene
terephthalate may be separately synthesized; the
resultant polymers may be blended, or composite spun
(sheath-core, side-by-side or the like). Examples of the
third component to be added include aliphatic
dicarboxylic acids such as oxalic acid and adipic acid,
alicyclic dicarboxylic acids such as
cyclohexanedicarboxylic acid, aromatic dicarboxylic acids
such as isophthalic acid and sodiumsulfoisophthalic acid,
aliphatic glycols such as ethylene glycol, 1,2-propylene
glycol and tetramethylene glycol, alicyclic glycols such
as cyclohexanedimehthanol, aliphatic glycols including an
aromatic group such as 1,4-bis(β-hydroxyethoxy)benzene,
polyether glycols such as a polyethylene glycol and a
polypropylene glycol, aliphatic oxycarboxylic acids such
as ω-oxycaproic acid and aromatic oxycarboxylic acids
such as p-oxybenzoic acid. Moreover, a compound such as
benzoic acid or glycerin having one, or three or more
ester-forming functional groups can also be used so long
as the resultant polymer is substantially linear.
-
A polytrimethylene terephthalate fiber may be
produced by any of the following methods: a draw-twisting
method wherein an undrawn yarn is obtained at a winding
rate of about 1,500 m/min, and the yarn is drawn and
twisted in a ratio of about 2 to 3.5; a direct drawing
method (spin draw method) in which spinning, and drawing
and twisting are continuously connected; and a high speed
spinning method (spin take up method) in which the
winding speed is 5,000 m/min or more. A polytrimethylene
terephthalate-based fiber can be obtained by spinning a
resin composition containing delustering agents such as
titanium oxide, stabilizing agents such as phosphoric
acid, ultraviolet ray absorbing agents such as a
hydroxybenzophenone derivative, nucleating agents such as
talc, lubricating agents such as Aerosil, antioxidants
such as a hindered phenol derivative, flame retardants,
antistatic agents, pigments, fluorescent brighteners,
infrared ray absorbing agents, defoaming agents and the
like.
Best Mode For Carrying Out the Invention
-
The idea of the present invention will be made more
specific and clear by making reference to examples. The
present invention is, however, not restricted thereto.
In addition, the preparation of a yarn used in the
examples, the measurement of the size of an elastic yarn
and the evaluation of the properties of a two-way warp
knitted fabric are described below.
- (1) Preparation of Polymethylene Terephthalate Yarn
A polytrimethylene terephthalate showing an ηsp/c =
0.5 is spun at a spinning temperature of 265°C at a rate
of 1,200 m/min to give an undrawn yarn. The yarn is
subsequently drawn and twisted at a hot roll temperature
of 60°C and a hot plate temperature of 140°C at a drawing
speed of 800 m/min with a draw ratio of 3 to give two
stretched yarns of 40 dtex/34 f and 56 dtex/36 f. The
stretched yarn of 40 dtex/34 f has a strength of 2.7
cN/dtex, an elongation of 44%, an initial tensile
resistance of 25 cN/dtex and an elastic recovery of 97%
when stretched by 10%. The stretched yarn of 56 dtex/36
f has a strength of 2.8 cN/dtex, an elongation of 46%, an
initial tensile resistance of 26 cN/dtex and an elastic
recovery of 98% when stretched by 10%. In addition, the
elastic recovery of a yarn at the time of stretching by
10% is obtained in the following manner. An initial load
of 0.01 cN/dtex is applied to the sample, and stretched
at a constant stretching rate of 20%/min; the sample is
conversely allowed to shrink at the same rate when the
stretch ratio reaches 10%. As a result, a stress-strain
curve is depicted. The elastic recovery is calculated
from the following formula:
elastic recovery at the time of a stretch ratio of
10% = (10 - L)/10 x 100 (%)
wherein L is a residual stretch ratio when the stress is
lowered to 0.01 cN/dtex that is equal to the initial load
during shrinking. The viscosity of polymer, ηsp/c is determined by
dissolving a polymer in o-chlorophenol at 90 degree
Celsius to prepared a solution at a concentration of 1
g/dl which is then transferred to Ostowald viscometer to
measure at 35 degree Celsius, and calculating using the
data obtained according to the following formula.
ηsp/c = (T/T0 1)/C
(T: falling time of the solution, C: concentration of
the solution [g/dl])
- (2) Measurement of Size of Elastic Yarn
An elastic yarn is allowed to stand on a straight
line without tension and load in an atmosphere at 20°C
with an RH (relative humidity) of 65% to be allowed to
shrink. Ten pieces of the yarn each 1 m long prepared by
cutting the yarn are weighed, and the size is determined
by the weight of the yarn per 10,000 m calculated from
the weighed value.
- (3) Evaluation of a two-way warp knitted fabric in
examples is made by the following methods.
- [1] Evaluation of Curl Manifestation
Two square test pieces, 100 mm (warp direction) x
100 mm (weft direction), of a two-way warp knitted fabric
are prepared. The two test pieces are allowed to stand
still on a horizontal stool in an atmosphere at 20°C with
its humidity conditioned to an RH of 65% while the needle
loop side and sinker loop side are placed upward. Four
hours after allowing the test pieces to stand still, the
results are judged according to the following criteria.
A protractor is attached to a cured portion, and the
angle () made by the tangential line of the tip of the
cured portion with the horizontal stool is determined.
When the curl angle is 90° or more, the treatment of the
fabric during sewing causes a problem. The rating
criteria are as follows.
- 5
- The curl angle is less than 30°.
- 4
- The curl angle is less than 45°.
- 3
- The curl angle is less than 90°.
- 2
- The curl angle is less than 130°.
- 1
- The curl angle is 130° or more.
- [2] Evaluation of Feeling
The sensory test results of hand feeling by 10
panelists are judged from the average value. The fabric
having the same construction prepared from a nylon fiber
is used as a reference feeling. A sample excellent in a
soft hand feeling is evaluated to be from 4 to 5 points.
A sample that can be hardly judged to be excellent or
poor therein is evaluated to be 3 points. A sample that
is judged to be poor therein is evaluated to be from 1 to
2 points. The sample is judged by the total points.A sample is judged by handling according to the
following criteria.
- 5 points
- The sample gives an extremely soft and
smooth feeling.
- 4 points
- The sample gives a soft and smooth
feeling.
- 3 points
- The sample gives a feeling that is the
same as that of a knitted fabric formed
from a nylon fiber and having the same
texture.
- 2 points
- The sample gives a hard feeling.
- 1 point
- The sample gives a hard feeling, and is
inappropriate to underwear applications.
- [3] Evaluation of Yellowing Tendency
Evaluation of a yellowing tendency of a sample is
made in accordance with the weak test method in the JIS
L-0855 test method of color fastness against nitrogen
oxide gas. The results are judged by comparing the YI
value that is obtained by a Macbeth colorimeter
(manufactured by Macbeth) with that of a non-treated
sample. When the YI value of a sample is larger, the
tendency toward yellowing thereof is more significant.
- [4] Evaluation of Heat Formability
A heat forming test machine manufactured by Daito is
used. A sample, 300 mm (warp direction) x 300 mm (weft
direction), is prepared by cutting a fabric. The sample
is fixed to a frame (200 mm (warp direction) x 200 mm
(weft direction)) under a free tension. The sample is
marked by pressing the central portion with a heated
mold. The sample is then allowed to stand for 24 hours
in an atmosphere at 20°C with an RH of 65%. The deformed
amount and change in the feeling of the fabric are
subsequently evaluated.The test is conducted under the following
conditions:
- Heat forming test machine: a stretch forming machine
manufactured by Daito;
- Shape of the heater mold: a metal-made cylinder (50
mm in diameter and 30 mm in height);
- Temperature: 180°C;
- Period of time: 30 sec; and
- Pressing depth: 20 mm
The rating criteria are as follows:
- Good:
- the deformation amount of the sample is 18
mm or more, and the sample shows no change
in the feeling; and
- Poor:
- the deformation amount of the sample is
less than 18 mm, and the sample shows a
change in the feeling.
- [5] Evaluation of Gigging (raising) property
-
-
The sinker loop surface of a gray fabric is gigged
with a gigging test machine (trade name of KU-50 type,
manufactured by Kanai juyo Kogyo Co., Ltd.) under the
conditions of a loop pile, and the uniformity is
evaluated and the thickness of the fabric is measured. A
fabric showing a larger judgment criterion thickness
shows a better gigging property.
Example 1
-
A polytrimethylene terephthalate yarn of 40 dtex/34
f was used as the front bar yarn. An elastic yarn
obtained by warping a polyurethane-based elastic yarn
(trade name of Roica, manufactured by Asahi Chemical
Industry Co., Ltd.) of 22 dtex with a draft ratio of 80%
was used as the back bar yarn. A half tricot stitch was
knitted.
-
The knitting conditions are as follows:
- Knitting machine: tricot machine (manufactured by
Carl Meyer) of 28 gauge/2.54 cm;
- Texture: front: 10/23, and back:12/10
- Runner lengths: front: 160 mm, and back: 90 mm
- Courses on the machine: 76 courses/2.54 cm
-
-
The knitted fabric thus obtained under the knitting
conditions was scoured at 90°C for 1 minute, and preset
at 190°C for 45 sec. The density during presetting was
set as follows: a (number of courses)/(number of wales)
density ratio of 1.83; and 110 courses/2.54 cm x 60
wales/2.54 cm. The fabric was then dyed with a liquid-jet
dyeing machine. The fabric was further finish set
under the same conditions as in the presetting: 110
courses/2.54 cm, and 60 wales/2.54 cm. That is, the
fabric was finish set with the same present length and
same present width to give a two-way warp knitted fabric.
The finished two-way knitted fabric had a basis of weight
of 170 g/m2 and a thickness of 0.61 mm. Various physical
properties of the fabric were evaluated, and the results
are shown in Table 1. The two-way warp knitted fabric
thus obtained did not yellow, gave a soft feeling, did
not produce a curling phenomenon, excelled in
formability, and was most appropriate to underwear
applications.
Examples 2 to 5
-
In Example 2, a sample was prepared in the same
manner as in Example 1 except that the front runner was
made short in comparison with that in Example 1 to form a
gray fabric with a high density construction, and that
the (number of courses)/(number of wales) density ratio
was set at 1.93.
-
In Example 3, a sample was prepared in the same
manner as in Example 1 except that the front runner was
made long in comparison with that in Example 1 to form a
gray fabric with a low density, and that the (number of
courses)/(number of wales) density ratio was set at 1.55.
-
In Example 4, a sample was prepared in the same
manner as in Example 1, except that the back runner was
made short in comparison with that in Example 1 to form a
gray fabric with a high density construction, and that
the (number of courses)/(number of wales) density ratio
was set at 1.81.
-
In Example 5, a sample was prepared in the same
manner as in Example 1, except that the back runner was
made long in comparison with that in Example 1 to form a
gray fabric with a low density, and that the (number of
courses)/(number of wales) density ratio was set at 1.70.
-
The curl manifestation, feeling, yellowing tendency
and formability of each of the finished knitted fabrics
were evaluated. Table 1 shows the results thus obtained.
-
The finished two-way warp knitted fabrics did not
yellow, gave a soft feeling, produced no curling,
excelled in formability, and were most appropriate warp
knitted fabrics for use in underwears.
Comparative Example 1
-
A sample knitted fabric was prepared in the same
manner as in Example 1 except that a gray fabric with a
high density was formed by making the back bar runner
length short, and that the (number of courses)/(number of
wales) density ratio was set at 2.37 during presetting to
change the density of the finished knitted fabric. The
curl manifestation, feeling, yellowing tendency and
formability of the knitted fabric were evaluated. Table
1 shows the results thus obtained. The two-way warp
knitted fabric thus obtained did not yellow, and gave a
feeling as soft as that of the nylon. However, it
produced a curling phenomenon, and became a warp knitted
fabric inappropriate to underwear applications.
Comparative Example 2
-
A knitted fabric sample was prepared in the same
manner as in Example 1 except that a gray fabric with a
coarse density was formed by making the front bar runner
length short, and that the (number of courses)/(number of
wales) density ratio was set at 1.52 during presetting to
change the density of the finished knitted fabric. The
curl manifestation, feeling, yellowing tendency and
formability of the knitted fabric were evaluated. Table
1 shows the results thus obtained.
-
The two-way warp knitted fabric thus obtained did
not yellow, and gave a soft feeling. However, since it
produced a curling phenomenon, and it became
inappropriate to underwear applications. Moreover, the
knitted fabric showed poor formability.
Example 6
-
A polytrimethylene terephthalate yarn of 40 dtex/34
f was used as the front bar yarn. An elastic yarn
obtained by warping a polyurethane-based elastic yarn
(trade name of Roica, manufactured by Asahi Chemical
Industry Co., Ltd.) of 22 dtex with a draft ratio of 80%
was used as the back bar yarn. A half tricot stitch was
knitted.
-
The knitting conditions are as follows:
- Knitting machine: a tricot machine of 36 gauge/2.54
cm;
- Texture: front: 10/23, and back: 12/10,
- Runner lengths: front: 160 mm, and back: 76 mm,
- Courses on the machine: 80 courses/2.54 cm.
-
-
The gray knitted fabric thus obtained was relax
scoured at 90°C for 1 minute, and preset at 190°C for 45
sec. The density during presetting was set as follows: a
(number of courses/(number of wales) density ratio of
2.25; and 180 courses/2.54 cm x 80 wales/2.54 cm. The
fabric was then dyed with a liquid-jet dyeing machine.
The fabric was then finish set under the same conditions
as in the presetting: 157 courses/2.54 cm x 70 wales/2.54
cm. The finished two-way warp knitted fabric had a basis
of weight of 138 g/m2 and a thickness of 0.51 mm.
Various physical properties of the fabric were evaluated,
and the results are shown in Table 1.
Examples 7 to 8
-
In Example 7, a finished knitted fabric sample was
prepared in the same manner as in Example 6 except that
the front runner and the back runner were made short in
comparison with those in Example 6 to form a dense gray
fabric, and that the (number of courses)/(number of
wales) density ratio was set at 2.35 to change the
density of the finished fabric.
-
In Example 8, a finished knitted fabric sample was
prepared in the same manner as in Example 6 except that
the front and the back runner were made long in
comparison with those in Example 6 to form a coarse gray
fabric, and that the (number of courses)/(number of
wales) density ratio was set at 1.85 to change the
density of the finished fabric. The curl manifestation,
feeling, yellowing tendency and formability of each of
the finished knitted fabrics were evaluated. Table 1
shows the results thus obtained. The two-way warp
knitted fabrics did not yellow, gave a soft feeling,
produced no curling, excelled in formability, and were
most appropriate to underwear and swimwear applications.
Comparative Example 3
-
A sample was prepared in the same manner as in
Example 6 except that the front runner length and the
back runner length were made long, that the (number of
courses)/(number of wales) density ratio was set at a
value as low as 1.54 during presetting, and that the
density of the finished knitted fabric was varied. The
curl manifestation, feeling, yellowing tendency and
formability of the finished knitted fabric were
evaluated. Table 1 shows the results thus obtained. The
finished two-way warp knitted fabric did not yellow, and
gave a soft feeling. However, it produced a curling
phenomenon, and was inappropriate for use.
Comparative Example 4
-
A finished knitted fabric sample was prepared in the
same manner as in Example 6 except that the back runner
was made short to give a gray fabric having a high
density, that the (number of courses)/(number of wales)
density ratio was set at a value as high as 2.38 during
presetting, and that the density of the finished knitted
fabric was varied. The curl manifestation, feeling,
yellowing tendency and formability of the finished
knitted fabric were evaluated. Table 1 shows the results
thus obtained. The finished two-way warp knitted fabric
did not yellow, and gave a soft feeling. However, it
produced curling, showed poor formability, and was
inappropriate for use.
Example 9
-
A polytrimethylene terephthalate yarn of 56 dtex/36
f was used as the front bar yarn. An elastic yarn
obtained by warping a polyurethane-based elastic yarn
(trade name of Roica, manufactured by Asahi Chemical
Industry Co., Ltd.) of 44 dtex with a draft ratio of 80%
was used as the back bar yarn. A half texture was
prepared by knitting the yarns.
-
The knitting conditions are as follows:
- Knitting machine: tricot machine of 28 gauge/2.54
cm,
- Texture: front: 10/23, and back: 12/10
- Runner lengths: front: 165 mm, and back: 80 mm
- Courses on the machine: 81 courses/2.54 cm.
-
-
The knitted fabric obtained under the above
conditions was relax scoured at 90°C for 1 minute, and
preset at 190°C for 45 sec. The density during
presetting was set as follows: a (number of
courses)/(number of wales) density ratio of 1.92; and 115
courses/2.54 cm x 60 wales/2.54 cm. The fabric was then
dyed with a liquid-jet dyeing machine. The fabric was
further finish set under the same number of courses/2.54
cm and the same number of wales/2.54 cm to give a two-way
warp knitted fabric. The finished two-way warp knitted
fabric had a basis of weight of 227 g/m2 and a thickness
of 0.66 mm. Various physical properties of the fabric
were evaluated, and the results are shown in Table 1.
-
The finished knitted fabric did not yellow, gave a
soft feeling, produced no curling phenomenon, excelled in
formability and a gigging tendency, and as most
appropriate to underwear and swimwear applications.
Comparative Example 5
-
A knitted fabric was formed in the same manner as in
Example 9 except that a nylon 6 yarn of 56 dtex/36 f was
used as the front bar yarn. The results of evaluating
the knitted fabric thus obtained are shown in Table 1.
The knitted fabric gave a soft feeling. However, since
the knitted fabric had the following disadvantages, it is
difficult to handle: the fabric tended to yellow; it
produced curling; and it showed poor setting and poor
uniformity during gigging.
Comparative Example 6
-
A knitted fabric was prepared in the same manner as
in Example 9 except that a polyethylene terephthalate
yarn of 56 dtex/36 f was used as the front bar yarn.
-
The results of evaluating the knitted fabric thus
finished are shown in Table 1. Although the finished
knitted fabric did not yellow and produced no curling
phenomenon, it gave a hard feeling and showed a poor
gigging tendency though it had a good capacity for being
set. The fabric therefore is not suitable for underwear
and swimwear applications.
Example 10
-
A polytrimethylene terephthalate yarn of 56 dtex/36
f was used as the front bar yarn. An elastic yarn
obtained by warping a polyurethane-based elastic yarn
(trade name of Roica, manufactured by Asahi Chemical
Industry Co., Ltd.) of 44 dtex with a draft ratio of 80%
was used as the back bar yarn. A knitted fabric with a
half texture was formed.
-
The knitting conditions are as follows:
- Knitting machine: a tricot machine of 28 gauge/2.54
cm
- Texture: front 10/23; back 12/10
- Runner lengths: front 206 mm, and back 80 mm
- Courses on the machine: 81 courses/2.54 cm.
-
-
The knitted fabric thus obtained was relax scoured
at 90°C for 1 minute, and preset at 190°C for 45 sec.
The density during presetting was set under the
conditions: a (number of courses)/(number of wales)
density ratio of 1.88; and 113 courses/2.54 cm x 60
wales/2.54 cm. The fabric was then dyed with a liquid-jet
dyeing machine. The fabric was then finish set with
the same number of courses/2.54cm and the same number of
wales/2.54 cm as in the presetting to give a two-way warp
knitted fabric. The finished two-way warp knitted fabric
thus obtained had a basis of weight of 280 g/m2 and a
thickness of 0.70 mm. Various physical properties of the
fabric were evaluated, and the results are shown in Table
1.
-
The finished knitted fabric did not yellow, gave a
soft feeling, produced no curling, excelled in
formability and a gigging tendency, and was a warp
knitted fabric most appropriate to underwear and swimwear
applications.
Example 11
-
A polytrimethylene terephthalate yarn of 56 dtex/36
f was used as the front bar yarn. An elastic yarn
obtained by warping a polyurethane-based elastic yarn
(trade name of Roica, manufactured by Asahi Chemical
Industry Co., Ltd.) of 44 dtex with a draft ratio of 80%
was used as the back bar yarn. A knitted fabric with a
half texture was formed under the following conditions:
- Knitting machine: tricot machine of 28 gauge/2.54 cm
- Knitting texture: front: 10/45, and back 12/10
- Runner lengths: front 250 mm, and back: 80 mm
- Courses on the machine: 81 courses/2.54 cm.
-
-
The knitted fabric thus obtained was relax scoured
at 90°C for 1 minute, and preset at 190°C for 45 sec.
The density during presetting was set under the
conditions: 110 courses/2.54 cm x 60 wales/2.54 cm. The
fabric was then dyed with a liquid-jet dyeing machine.
The fabric was then finish set with the same number of
courses/2.54cm and the same number of wales/2.54 cm as in
the presetting to give a two-way warp knitted fabric.
The finished two-way warp knitted fabric thus obtained
had a basis of weight of 280 g/m2 and a thickness of 0.72
mm. Various physical properties of the fabric were
evaluated, and the results are shown in Table 1.
-
The finished knitted fabric did not yellow, gave a
soft feeling, produced no curling phenomenon, excelled in
setting and a gigging tendency, and was a stretchable
warp knitted fabric most appropriate to underwear and
swimwear applications.
Comparative Example 7
-
A knitted fabric was formed in the same manner as in
Example 10 except that a nylon 6 yarn of 56 dtex/36 f was
used as the front bar yarn. Although the finished
knitted fabric gave a soft feeling, it tended to yellow,
and curls were formed. A sufficient deepness could not
be obtained, and the knitted fabric showed poor
formability and a poor gigging tendency and was difficult
to handle.
Comparative Example 8
-
A knitted fabric was formed in the same manner as in
Example 10 except that a polyethylene terephthalate yarn
of 56 dtex/36 f was used as the front bar yarn. Although
the knitted fabric showed good formability, it showed a
poor gigging tendency, and gave a hard feeling.
Accordingly, the fabric was not suitable for use.
Comparative Example 9
-
A knitted fabric was prepared in the same manner as
in Example 9 except that a polyethylene terephthalate
yarn of 56 dtex/36 f was used as the front bar yarn, that
the front runner and back runner were made longer than
those in Comparative Example 6 to form a coarse gray
fabric, and that the density was set at 94 courses/2.54
cm and 60 wales/2.54 cm during presetting.
-
Table 1 shows the results of evaluating the finished
knitted fabric. The fabric did not yellow, and gave a
softer feeling than the knitted fabric in Comparative
Example 6. However, the fabric gave no numeric
(phonetic; waxy to touch feeling specific to nylon. The
fabric was not suitable for underwear and swimwear
applications because it showed poor formability and a
poor gigging tendency, and because curls were formed.
Industrial Applicability
-
The two-way warp knitted fabric of the present
invention does not yellow, gives a soft feeling and a
unique surface touch that cannot be obtained from a
knitted fabric in which a nylon yarn is used, and is a
warp knitted fabric prevented from forming curls. The
knitted fabric is therefore excellent in handling such as
sewing, and is a stretchable warp knitted fabric most
suitable for sports and clothing applications such as
underwear and swimwear.
