U.S. patent number 3,824,776 [Application Number 05/217,060] was granted by the patent office on 1974-07-23 for fabric having improved pick resistance.
This patent grant is currently assigned to Burlington Industries, Inc.. Invention is credited to Joe F. London, Jr..
United States Patent |
3,824,776 |
London, Jr. |
July 23, 1974 |
**Please see images for:
( Certificate of Correction ) ( Reexamination Certificate
) ** |
FABRIC HAVING IMPROVED PICK RESISTANCE
Abstract
A fabric is provided of improved pick resistance containing a
textured, air jet interlaced yarn comprising a plurality of
continuous synthetic thermoplastic filaments. The yarn is further
characterized by uniform repeating sections of about 1/8- 1 inch in
length, each said section being composed of a relatively open bulky
and lofty portion of false twisted multifilaments and a relatively
short node portion where the multifilaments are closer together and
are interlaced and encircled.
Inventors: |
London, Jr.; Joe F.
(Greensboro, NC) |
Assignee: |
Burlington Industries, Inc.
(Greensboro, NC)
|
Family
ID: |
27509375 |
Appl.
No.: |
05/217,060 |
Filed: |
January 11, 1972 |
Current U.S.
Class: |
57/208; 57/245;
57/247; 57/908 |
Current CPC
Class: |
D02G
3/34 (20130101); D02G 1/16 (20130101); D02G
1/20 (20130101); D02G 1/0206 (20130101); Y10S
57/908 (20130101) |
Current International
Class: |
D02G
3/34 (20060101); D02G 3/34 (20060101); D02G
1/02 (20060101); D02G 1/02 (20060101); D02G
1/20 (20060101); D02G 1/20 (20060101); D02G
1/16 (20060101); D02G 1/16 (20060101); D02g
003/34 (); D02g 001/02 (); D02g 001/16 () |
Field of
Search: |
;57/14R,14J,14BY,157F,157R,157TS,34B,34R
;28/1.3,1.4,72.11,72.12 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Huckert; John W.
Assistant Examiner: Gorenstein; Charles
Claims
It will be appreciated from the foregoing that various
modifications may be made in the invention as described above.
Hence the scope of the invention is defined in the following claims
wherein what is claimed as new is:
1. A fabric of improved pick resistance containing a textured, air
jet interlaced yarn comprising a plurality of continuous synthetic
thermoplastic filaments, said yarn being characterized by uniform
repeating sections of about 1/8-1 inch in length, each said section
being composed of a relatively open bulky and lofty portion of
false twisted multifilaments and a relatively short node portion
where the multifilaments are closer together and are interlaced and
encircled.
2. A knit fabric according to claim 1.
3. A double knit fabric according to claim 1.
4. The fabric of claim 1 wherein the length of the node portion of
the yarn is from 1/10 to 1/5 of the length of the relatively open
portion.
5. A fabric according to claim 1 wherein the yarn comprises two
separately false twisted ends of yarn which have been
interlaced.
6. A fabric according to claim 5 wherein the one yarn end has
S-torque therein and the other end has Z-torque therein.
Description
The present invention relates to a textured yarn and process for
making same. More particularly, the invention is concerned with the
provision of textured yarn having improved pick resistance and
processability.
Textured yarns composed of, for example, polyester, nylon and/or
acetates, have found widespread use in woven and knitted fabrics,
including double knit fabrics which are becoming increasingly
important. While textured yarns are uniquely useful, a persistent
problem with such yarns is that fabric made therefrom tends to
suffer from filament picking or snagging when made from textured
continuous filament yarns which have little or no twist therein.
This problem can be overcome if the yarns are twisted to a
relatively high level to produce a fairly tight bundle but this is
usually undesirable because it is very costly and because the
twisting of filament yarn produces a very hard yarn which in the
case of textured yarn, completely destroys the textured appearance
of the yarn and its desired bulk and loft, thus making the yarns
unattractive for apparel fabric uses. Thus, it is evident that
there is a real need in the art to provide textured yarns which
retain their desired characteristics of bulk and loft while at the
same time having a high resistance to picking or snagging.
Another area where the use of textured yarns can be improved is in
the production of fabrics having a heather appearance. In recent
years, it has become increasingly popular to use combinations of
two cross-dyeable or different colored textured yarns to produce a
heather look in knit or woven fabrics. Conventionally, this has
been accomplished by plying the yarn ends together on a
conventional twister before knitting or weaving. However, this is
an expensive and relatively complicated operation and there is,
therefore, considerable room for improvement here towards providing
combinations of cross-dyeable or different colored textured yarns
for use in making fabrics having a heather appearance.
In keeping with the above, one of the principal objects of the
present invention is to provide textured yarns and fabrics
containing the same which demonstrate improved resistance to
picking and snagging. Another object of the invention is to provide
a process for making such textured yarns.
An additional object of the invention is to provide textured yarns
which are highly desirable for use in producing fabrics having a
heather appearance and a method for making such yarns which is much
more convenient and economical than procedures hitherto used.
Other objects will also be apparent from the following detailed
description of the invention.
Broadly speaking, the objects of the invention are realized by
moving one or more textured multifilament synthetic yarns through
an air jet flowing cocurrently with the direction of yarn movement
and introduced into the yarn at an angle of about
45.degree.-75.degree. so that the filaments in the textured yarn
are uniformly intermingled and entangled before the yarn is taken
up. Preferably, but not necessarily, the jet treatment is combined
with texturing of the yarn, e.g. the yarn is passed continuously
through a conventional false-twist texturing machine and subjected
to the action of the jet between texturing and the take-up of the
texturing machine.
The jet causes the filaments of the textured yarn to become
periodically entangled or wound together along the length of the
yarn so that there are not substantial lengths of the yarn where
individual filaments are free to slip and thus be receptive to
picking. One or more textured multifilament yarns may be subjected
to the air jet treatment, it being appreciated that two or more of
such yarns which are cross-dyeable or different colored can be so
processed to give a combination yarn suitable for providing heather
effects.
The yarn of the invention can be more fully described as an air jet
intermingled or interlaced textured yarn comprising a plurality of
continuous synthetic thermoplastic filaments, the yarn being
further characterized by relatively uniform repeating sections of
about 1/8-1 inch in length, each such section being composed of a
relatively open portion of bulky and lofty false-twisted
multifilaments and a relatively short node portion where the
multifilaments are brought closer together and are interlaced and
encircled.
The success of the invention is due to a number of important
features. For one thing, it has been found that relatively frequent
and uniformly occurring nodes or interlacing in repeating yarn
sections as defined above, are important from the standpoint of
pick resistance. In past uses of air jets for mingling textured
yarns, nodes or interlacings have been kept to a minimum and thus
the resulting products have not offered particularly improved pick
resistance.
Additionally, it is important for present purposes to use the
indicated combination of false-twist texturing and air jet
interlacing since the desired bulky and lofty textured product with
optimum pick resistance cannot be obtained if the texturing or air
jet is used alone.
It is also important to the success of the invention that the jet
air flow be cocurrent with the yarn direction rather than
counter-current thereto and it is preferred that the jet have a
stepped air/yarn passage. Air pressure and degree of yarn overfeed
are also important as is the angle at which the air is mixed with
the yarn. Other important features will also be evident
hereinafter.
The invention is more fully described in conjunction with the
attached drawings wherein:
FIG. 1 is a diagrammatic view of a false-twist texturing machine
including the air jet yarn interlacing feature of the
invention;
FIG. 2 is a vertical sectional view through a preferred form of air
jet according to the invention;
FIG. 3 is a vertical sectional view of another simpler form of air
jet which is suitable for use herein; and
FIG. 4 is a perspective view of the interlaced textured yarn of the
invention.
Referring more specifically to FIG. 1, which shows a texturing
machine for simultaneously and separately texturing two yarns,
yarns (2) and (4) are fed into the machine from supply packages (6)
and (8) by pulling the yarns over the ends of the packages into the
bottom rolls (10) of the texturing machine. As will be understood,
the bottom rolls (10) may be rotated at a speed such as to overfeed
or underfeed the yarns into the heater (12) of the texturing
machine.
Each of the yarns passes from the heater (12), which may be of any
conventional type (e.g. an electrically heated contact surface),
through its own false twist spindle (14) and (16), one of which
imparts a "Z" torque and the other an "S" torque. As known in the
art, the twist applied by spindles (14) and (16) extends downwardly
to heater (12) where the twist is heat set as in a conventional
texturing operation.
The yarns are pulled from the spindles by a pair of feed rolls (18)
which can either feed the yarns to a second heater (not shown) for
relaxation or directly to the take-up rolls (20). On a double
heater machine, the feed rolls (18) feed the yarns through the
second heater with overfeeds which are standard in false-twist
texturing and a third set of feed rolls pulls the yarn out of the
second heater and feeds it onto the take-up package. As indicated,
FIG. 1 does not show the double heater arrangement but this is not
essential for present purposes. According to the invention, the
textured yarns resulting from the false-twist heat-setting
operation are fed either directly or indirectly from rolls (18) to
take-up rolls (20) via an interlacing air jet (22) which interlaces
and entangles the textured yarns just before they are taken up on
rolls (20).
The preferred structure for air jet (22) is more fully shown in
FIG. 2. Basically the jet comprises a body (24), advantageously
tubular, of steel or other metal having a stepped tubular passage
or bore (26) running lengthwise thereof, the yarn or yarns and air
flow passing through passage (26) in the direction of the arrows.
The lengths and diameters of the several stepped bores or bore
sections (a), (b) and (c) of the passage may be varied although
section (b), which is where the air is introduced, should be at
least as long as, and preferably longer than the other two
sections. In one embodiment shown in FIG. 2, section (b) is about
10 percent longer than section (a), the yarn inlet section, and
about 50 percent longer than section (c), the discharge section.
These length relationships, however, can be varied although for
best overall results it is desirable to maintain the stepped
feature comprising three sections of diameter increasing from the
yarn inlet to the outlet. Advantageously, the yarn inlet section
(a) has the smallest diameter, the intermediate section (b), where
the air is introduced, has a diameter from 1.5 - 3 times larger
than that of section (a) and the diameter of discharge section (c)
is about 1.5 - 2 times larger than that of section (b) although it
will be recognized that other diameter relationships may also be
used. In any case, the diameter changes should be made gradually by
tapering the passage outwardly as shown to avoid undesired
turbulence.
Air is introduced into section (b) of the jet through member (28)
which is provided with an air inlet passage (30) positioned at an
angle of 45.degree.-75.degree., preferably at about a 53.degree.
angle to the yarn as shown in FIG. 2. Obviously the outer diameter
of the body (24) may be widely varied but a preferred dimension is
one wherein a straight line x--x drawn across the body (24) from
the center of the air passage (30) defines a length (d) which is
about 75-90 percent of the length of passage (a).
As shown in FIG. 2, passage (30) is reduced in diameter (usually by
about 2/3 - 3/4) as shown at (32) and discharges air into the yarn
in section (b) just beyond the point where section (b) begins. When
the air flow through (32) meets the yarn flow in section (b), the
filaments of the yarn or yarns are moved about in such a manner
that they are interlaced and entangled into nodes at very short and
regular intervals. The internodal distance is of the order of 1/8
to 1 inch, preferably 1/4 to 1/2 although it will be recognized
that this distance can be varied. It is important, to avoid
excessive winding and twisting, that the air stream contact the
yarn at essentially the exact center of the yarn.
FIG. 3 shows a simplified jet for use herein, the same numerals
being used in FIGS. 2 and 3 to define like parts. In the embodiment
of FIG. 3, the diameter of the yarn passage (26) is changed only
once from a relatively narrow inlet bore portion (a) to an
intermingling portion (b) and the air passage (30) is of uniform
diameter throughout. A preferred set of dimensions is given in FIG.
3.
The air pressure used in jet (22) has an effect on the degree of
interlacing, blending and quality of the ultimate product. The
optimum air pressure will depend on the nature of the yarn or yarns
utilized but it appears that for best overall results an air
pressure in the range of about 15-30 psig should be used for the
jet structure shown in FIG. 2. Pressures in this range give good
yarn quality and sufficient entanglement and interlacing to give a
product offering outstanding pick resistance. Higher pressures,
e.g. 25-30 psig can be used in certain circumstances but the yarn
may begin to look hairy and abnormal due to tight entanglement of
the filaments and the best overall yarn quality seems to be
realized at the indicated 15-30 psig range.
Another important variable is the degree of overfeed of the yarn
into the jet. It is important to balance the overfeed at this point
with the overfeed required to wind up the textured package. Too
much overfeed into the jet gives excessive yarn turbulence which
will form undesired loops in the jet. An overfeed of from 2 to 10
percent into the jet has been found very satisfactory. Below this
degree of overfeed, interlacing efficiency appears to be reduced
whereas above 6-8 percent there is some tendency to get looping of
the filaments and yarn entanglements which do not give a uniform
product although under other conditions, overfeeds may be increased
further.
The invention has been described above and illustrated in FIG. 1
using a false-twist texturing apparatus comprising spindles for
applying both S- and Z-torque. This type of apparatus is well known
and particularly convenient for use herein although any
conventional type of texturing apparatus may be used herein to
include the air jet feature for preparing intermingled textured
yarn. The S and Z arrangement illustrated in FIG. 1 has the
advantage that two yarns (2) and (4) can be processed separately
until the last feed roll (roll (18) in FIG. 1) where they are
combined and fed to the jet together to be interlaced and thus form
one individual yarn which has zero torque due to an equal
combination of S-torque and Z-torque in individual filaments,
thereby eliminating the need for post-heat setting or ply-twisting
to control torque levels.
It is not essential for present purposes to continuously texture
and intermingle as illustrated in FIG. 1. For example, the yarn may
be pre-textured and then subjected to the air jet in two separate
or discontinuous operations.
It will be appreciated that the arrangement of FIG. 1 lends itself
to a number of useful variations. Thus, in a particularly important
embodiment, a single end of multifilament yarn can be textured, the
filaments of the single end being intermingled in the jet (22)
using the arrangement of FIG. 2 to give a yarn which is uniquely
useful in preparing pick resistant knit fabrics. In another
important variation, a zero torque yarn can be prepared by
combining S and Z yarns of equal degree of torque as indicated
above. As a further alternative, two or more different colored or
differently dyeable yarns may be separately false-twisted and then
combined at the jet before going onto the take-up package. This
eliminates the need for ply-twisting different yarns to form
heather yarns and produces a more intimate blend of colors at a
much reduced processing cost.
The improved pick resistance of fabrics made with intermingled
textured yarn according to the invention is effectively shown by
the Mace snagging test or tester described below. Thus, for
example, conventional 150-denier textured multifilament polyester
yarn (not interlaced) knit in a Swiss pique fabric shows a pick
resistance grading of 3 to 2 when tested on the Mace snagging test
whereas identical yarn which has been interlaced according to the
invention at 15 psig on a conventional Scragg texturing machine
gives a pick resistance of 5 to 4 rating for double knit fabric.
This is a very significant improvement since 5 is considered
excellent while 3 is borderline acceptable.
The snag or pick ratings cited herein were determined on a
one-position Model B-612 Mace Snag Tester, manufactured by ABC
Machinery Corporation, Charlotte, N.C., based on the specifications
of the Mace Snag Tester of ICI Fibres Limited. The ICI instrument,
discussed in Textile Industries, December, 1970, pages 125-6, is
described in detail in the "Provisional Handbook for MK 2 `Mace`
Snag Tester and Viewing Cabinet," by W. A. Shepherd, Textile
Development Department, ICI Fibres Limited, Hookstone Road,
Harrogate, Yorks, England. Test specimens were compared with ICI
photographic standards, reference number DGH 1922, having ratings
from 1 to 5, with intermediate numbers 4-3, 5-4, etc., 5 indicating
zero snags. Only the number, not the type, of snags or picks was
evaluated. Ratings cited are the average of two measurements per
direction, wale and course, with tests re-run whenever paired
ratings were more than one unit apart. The precision of the mace
test, 95 percent confidence, is .+-.0.5 units.
The invention is useful with any type of continuous multifilament
synthetic yarn which is normally textured, e.g. polyester, nylon,
acetate, acrylic or the equivalent, or combinations thereof, in
either the same or separate yarns. Representative of such yarns is
2/70 denier, 68 filament polyester yarn or 150 denier, 34 filament
polyester yarn.
A wide variety of fabric constructions may be made with the yarns
of the invention to give the indicated pick resistance and/or
heather effect, e.g. double knits.
The interlaced textured yarn of the invention as shown in FIG. 4
comprises a plurality of continuous synthetic thermoplastic
filaments (34), the yarn being further characterized by relatively
uniform repeating sections (36) of about 1/8 - 1 inch in length,
each said section being composed of a relatively open portion (37)
of bulky and lofty false-twisted multifilaments and a relatively
short node portion (38) where the multifilaments are brought closer
together and are interlaced or encircled.
While the invention has been described above with particular
reference to providing improved pick resistance, or heather
effects, it should be noted that the intermingled textured yarns of
the invention also provide other advantages in weaving and knitting
fabric therefrom. Thus, for example, the intermingled or
mechanically bonded filaments prepared herein are particularly
advantageous for use in warp knitting and weaving where warping is
necessary. A major problem in warping is caused by loose or flaring
filaments from a yarn bundle since most textured yarns are very
open or twistless. However, when these yarns are interlaced
periodically along the length of the yarn after texturing according
to the invention, flaring filaments and loose filament bundles are
eliminated or controlled and greater efficiency in knitting and
warping is obtained.
The invention is illustrated by the following examples:
EXAMPLE 1
Textured yarns of 70/34 Z-torque white and 70/34 S-torque black
nylon, each having 1/4 turn per inch of producer twist, were fed
together through an interlacing apparatus designed to provide
controlled overfeeding between the overfeed rolls and feed rolls to
the winder. The stepped jet of FIG. 2 (outside diameter (e) 0.785
inch; bore (a) 0.870-inch length, 0.0595-inch diameter, number 53
drill; bore (b) 0.953-inch length, 0.1285-inch diameter, number 30
drill; bore (c) 0.647-inch length, 0.1960-inch diameter, number 9
drill; length (d) 0.7375 inch) was set between the two pairs of
rolls to interlace the two yarns. The interlaced yarn was wound
onto a constant-tension take-up. The yarns were interlaced in
successive runs at eight inlet air pressures ranging from 5 to 40
psig, at overfeeds of 1 percent. The resulting interlaced yarns
were visually rated, relative to each other, on a 1-to-8 scale, in
terms of degree of blending (judged by color uniformity), degree of
interlacing, and overall appearance. When the results were plotted
against the pressure, it was evident that blending and interlacing
reached a maximum at about 20-25 pounds. Yarn appearance, after
improving up to about 20 pounds, decreased drastically with further
increase in pressure. The decrease was attributed to the onset of
excessive interlacing and knotting. A similar tabulation of runs
where pressure was held at 20 psig while the overfeed was varied
from zero to 4 percent led to the conclusion that an overfeed of
about 2 percent was optimum for this yarn. In general it is
believed that overfeed should be as high as can be tolerated, short
of looping the filaments, to provide maximum opportunity for
interlacing. Subsequent tests showed that higher overfeeds and
pressures were required as the denier-per-filament size of the
yarns increased.
A similar set of runs using the jet of FIG. 3 produced no
perceptible differences in the results. It was concluded that
although the enlarged exit of the FIG. 2 jet did not visibly affect
the quality of the output yarn, compared with the FIG. 3 jet, it
did both quiet the noise of the jet and make it easier to align the
drilling of the interlacing chamber and the final placement of the
jet. The FIG. 2 jet was accordingly used in the subsequent
examples.
EXAMPLE 2
Textured yarns of S-torque 70/34 Type 56 standard disperse-dyeable
Dacron polyester and Z-torque 70/34 Type 92 acid-dyeable Dacron
polyester were drawn from packages through the stepped jet of
Example 1, using conditions of 20 psig air pressure, 2 percent
overfeed, and 150 ypm throughput. Both processing smoothness and
product uniformity were good; and the output yarn, when converted
to a single-knit jersey and dyed with an acid dye, produced a
pleasing heather effect. The appearance contrasted most favorably
with the same jersey made from a two-color plied yarn, which
latter, because of a strong tendency to an erratic patterning,
produced an irregularly barred and twill-like effect.
EXAMPLE 3
Textured yarns of 70/17 S-torque Type 56 and Z-torque Type 92
Dacron were successfully interlaced by the procedure of Example 1
by increasing the air pressure of the stepped jet to 28 psig and
the overfeed to 3 percent. It was evident that the yarn
composition, particularly its denier per filament, was a
significant factor in determining the optimum operating conditions
for applying this invention.
EXAMPLE 4
Six of the stepped jets of Example 1 were installed above the top
feed rolls of 12 positions of a Scragg Model CS-12 single-heater
texturing machine, equipped to texture with S- and Z-torque on
alternate positions, as shown in FIG. 1. Each pair of feed yarns of
70/34 Type 92 and 70/34 Type 56 Dacron were textured with S- and
Z-torque, respectively, and then passed together through a jet for
interlacing, at 15 psig air pressure and 6 percent overfeed to the
package, the overfeed being increased over earlier examples to give
a good package, and the pressure reduced to prevent knotting. The
yarn thus produced, showing nodes at 3/8-inch intervals, was
knitted into a double-knit fabric for comparison, after dyeing,
with a control fabric of indentical structure except that the
latter fabric was made from a 150/34 Type 56 Dacron, textured and
set but not interlaced. Both fabrics were tested for pick
resistance on the Mace Snag Tester. The interlaced fabric had a
near-perfect snag rating of 5-4, measured both length- and
widthwise, while the other fabric had a borderline rating of 3-2
lengthwise and a low rating of 2 widthwise. Double-knit fabrics in
a much looser Swiss-pique stitch from the same yarns had even more
pronounced differences in pick resistance which, though slightly
lower than before for both fabrics, further accented the
pick-resistant merit of the fabrics of the invention. They had the
additional advantage of an attractive heather effect when dyed.
Their pick-resistance ratings are shown in Table 1.
TABLE 1 ______________________________________ Mace Test Ratings of
Loose-Knit Fabrics from Interlaced and Non-interlaced Yarns
______________________________________ Yarn Type Fabric Side Mace
Rating ______________________________________ Length Width
______________________________________ Interlaced Face 3-2 5-4
Non-interlaced Face 1 3 Interlaced Back 4 5-4 Non-interlaced Back
4-3 3 ______________________________________
EXAMPLE 5
In this example a 150/34 Type 56 Dacron was drawn from a supply
package through a single-heater Model CS-12 Scragg texturing
machine and thence through the stepped jet of Example 1. The yarn
did not interlace well until the air pressure was increased to 24
psig and the overfeed to the supply package to 8 percent. This
example further shows the close relationship existing among the
variables of filament denier, air pressure, and overfeed.
EXAMPLE 6
The effects of variations in the stepped jet of Example 1 upon the
entangling behavior of 150/34 Type 56 Dacron yarn are described in
this example. Dimensions were as shown in Example 1 except where
otherwise stated. Changes were made in the inlet air pressure of
the jet, the angle of air impact upon the yarn, and the diameter of
the interlacing chamber, as detailed in Table 2. Letter references
(b) and (d) in the table are to the corresponding designations in
FIG. 2. The yarn was fed through the first and middle rolls of an
ARCT FTF double-heater machine (heaters at 200.degree. and
210.degree. C., respectively) at 73 meters/minute, through the top
rolls at 63.5 meters/minute, through the jet, and thence onto the
takeup package at 64.1 meters/minute. The interlacing
characteristics of the yarns produced by each jet are described in
Table 3.
TABLE 2 ______________________________________ Variations in
Dimensions of Interlacing Jets
______________________________________ Jet No. Inlet Angle
(Degrees) Inlet Entry Point, (d) (Inches) Interlacing Chamber
Diameter, (b) (Inches, Drill Size)
______________________________________ 1 53 0.7375 0.1285 (No. 30)
2 53 0.8375 0.1285 (No. 30) 3 38 0.5305 0.1285 (No. 30) 4 68 0.8735
0.1285 (No. 30) 5 53 0.7375 0.0980 (No. 40) 6 53 0.7375 0.1610 (No.
20) ______________________________________
TABLE 3 ______________________________________ Characteristics of
150/34 Type 56 Dacron Yarn Interlaced in Jets of Table Air Pressure
______________________________________ Jet No. 16 psig 22 psig 28
psig ______________________________________ 1 Interlacing fair;
nodes 3/8" apart Interlacing good; nodes 3/8" apart Interlacing
good; nodes 3/8" apart; some loops 2 Interlacing fair; nodes 3/8"
apart Interlacing good; nodes 3/8" apart Interlacing good; nodes
3/8" apart; some loops 3 Interlacing very poor Interlacing poor;
nodes widely separated Interlacing poor; nodes about 1/2 to 5/8"
apart 4 Interlacing good; nodes 1/4" apart Interlacing better than
at 16 psig; nodes 1/4" Interlacing better than at 22 psig; nodes
1/4" apart 5 Interlacing poor; nodes 1/4" apart Interlacing poor;
nodes 1/4" apart Interlacing fairly good; nodes 1/4" apart; some
loops 6 Interlacing poor Interlacing fair Interlacing fairly good;
nodes about 1/2" apart; some loops
______________________________________
From these results it is apparent, with this yarn, that an air
inlet angle centered around 53.degree. seems optimum, that
increasing the angle decreases the distance between the nodes, that
decreasing the angle increases the distance between the nodes and
soon seriously decreases the entangling, that minor changes in the
location of the gas inlet port have no detectable effect, and that
variations, whether up or down, in the diameter of the interlacing
chamber from a value around 1/8 inch soon become harmful to the
interlacing process. It had earlier been recognized that precise
alignment of the inlet tube to assure that the air would strike the
yarn dead-center in the interlacing tube was imperative, to avoid
undesirable twisting caused by rotation of the yarn bundle.
The frequency of the nodes seems to be a function of both the
diameter of the interlacing chamber and the air inlet angle, the
sensitivity to minor changes in either of these parameters being
fairly great. As the inlet angle rises above 53.degree., both the
length and frequency of the nodes tend to increase. This has the
effect of simultaneously increasing the pick resistance, but
caution must be taken not to go too far. Otherwise, excessive loss
of loft and covering power in the yarn and the fabrics made from it
may occur.
It seems, further, that too small an interlacing chamber diameter
confines the yarn excessively, while too large a chamber permits it
to move about more freely than is desirable, either effect being
harmful to the yarn properties.
On the whole it appears that for this yarn an inlet angle of
53.degree., an interlacing chamber diameter of about 1/8 inch, and
an inlet air pressure of 22 psig are the optimum operating
conditions. Best conditions for other yarns will differ from these
to some degree, but it is well within the skill of the art to
determine such conditions by simple experimentation following the
teachings of this invention.
EXAMPLE 7
An attempt was made to turn the jet of Example 1 around so that the
air, at 22 psig, flowed countercurrent to the 150/34 Type 56 Dacron
yarn. The same yarn speed conditions were applied as in Example 6,
except that, to avoid lap-ups caused by the excessive overfeed, the
take-up rate had to be increased to 67.9 meters/minute. The
resulting yarn had only a small amount of interlacing, the nodes
being infrequent and easily pulled out upon extending the yarn
slightly. The combination of low overfeed and limited interlacing
thus resulted in excessive loss of both covering power and pick
resistance. It was concluded from this experiment that the
pick-resistant yarn of this invention could be obtained only by
using a concurrent-flow jet.
EXAMPLE 8
In this example a comparison was made between the pick resistance
of fabrics made from a textured interlaced yarn of this invention
and a twisted yarn. The interlaced yarn was the 150/34 Type 56
Dacron of Example 5, while the twisted yarn was made by plying two
ends of textured 100/34 Type 56 Dacron having six turns of Z twist.
The interlaced yarn was knitted into a 6.10-g/yd.sup.2 Swiss-pique
and the other into a 9.37-g/yd.sup.2 Swiss-pique, and the fabrics
were submitted to the Mace test. Results are summarized in Table
4.
TABLE 4 ______________________________________ Mace Test Ratings of
Fabrics from Interlaced and Twisted
______________________________________ Yarns Yarn Type Fabric Side
Mace Rating ______________________________________ Length Width
______________________________________ Interlaced Face 4 3 Twisted
Face 4-3 3 Interlaced Back 5-4 5-4 Twisted Back 5-4 4-3
______________________________________
Especially taking into account that the fabric from the twisted
yarn had the advantages of both a higher-denier yarn and a
heavier-weight fabric, each of which should improve the pick
resistance, it is believed that these results indicate that the
interlaced yarn is equal or perhaps even superior to the twisted
yarn.
EXAMPLE 9
Five samples of 150/34 Type 56 Dacron yarn were textured, two on
the Scragg CS-12 single-heater machine and three on the ARCT FTF
double-heater machine, for a carefully controlled comparison of
interlaced with non-interlaced yarns. Preparations of samples 1 and
2, textured on the Scragg and then autoclaved at 230.degree. F.,
differed only in that a stepped jet of Example 1 was operated, at
24 psig, above the final feed roll of sample 2, but not of control
sample 1. Operating conditions were:
Bottom overfeed +1% Top Overfeed +8% Heater temperature
200.degree.C. Twist 63 tpi Yarn speed 106 yds/min
Samples 3, 4 and 5 were textured on the ARCT FTF machine, with no
jet with sample 3, an Example 1 jet at 22 psig with sample 4, and a
28 psig jet with sample 5, both jets being between the top roll and
the take-up package. Operating conditions were:
Bottom overfeed 0% Second overfeed +13.7% Top overfeed -1.75% Twist
63 tpi Yarn speed 73 meters/min Bottom heater temperature
200.degree.C Top heater temperature 210.degree.C
All five yarns were then knitted with a Ponte-di-Roma stitch on an
18-cut machine, and the resulting fabrics were dyed a smoke-grey
for easy observation of picks. Table 5 shows the results obtained
on the mace tester.
Table 5 ______________________________________ Mace Test Ratings of
Knitted Fabrics from Yarns Made on Texturing Machines with and
Without Integral Jets ______________________________________ Sample
Face Rating Back Rating Length Width Length Width
______________________________________ (not interlaced) 3 2 3 4 2
(interlaced) 5-4 4 4 5-4 3 (not interlaced) 4-3 4-3 4 3 4
(interlaced) 4 5-4 4 5-4 5 (interlaced) 4 4 4 5-4
______________________________________
These data show a pattern of significantly improved pick ratings of
the interlaced-yarn fabrics over their non-interlaced controls.
Comparison of Samples 4 and 5 indicates, on the ARCT machine and
with the 150/34 Dacron yarn, that an air pressure of 22 psig was
sufficient to provide maximum pick resistance and that there was no
merit in applying the noisier and more expensive 28 psig air
pressure.
The textured yarn and method and apparatus of making the same as
described herein are claimed in a copending application (Docket
505) filed on even date herewith.
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