Aug. 10, 1965 COMPOSITE S.B.

MAEROV ETAL
POSEER YARN OF DIFFERENTIALLY
3,199,281
SHRINKABLE CONTINUOUS FIAMENTS
Filed Sept. 27, 196l. 2 Sheets-Sheet

F.G.

INVENTORS
SIDNEY B. MAEROV
EUGENE. B. MC CORD

BY javé C l they
Aug. 10, 1965 COMPOSITE F6LYESER
S.B. MAEROV ETAL
YARN OF DIFFERENTIALLY
3,199,281
SHRINKABLE CONTINUOUS FIAMENTS
Filied Sept. 27, 196 2. Sheets-Sheet 2

2 2 (or 32)

INVENTORS
SIDNEY B. MAEROV
EUGENE B. MC CORD

ATTORNEY
United States Patent Office 3,199,281
Paterated Aug. 20, 1965

an improved composite continuous filament linear con

3,199,281 densation polyester yarn which can be caused to become
COMP3OSTE PEYESTERYARN OF DFFER permanently bulky by a simple treatment which can be
ENTALY SERENEXABLE CONTNUOUS applied to the yarn either before or after the yarn is
F AMENTS
Sidney B. Maeroy and Eugenie B. McCord, Kinston, N.C., 5 Woven or knitted into fabric, as desired. Another object
assignors to E. I. du Point de Nemcurs and Company, is to provide such a composite polyester yarn which,
Wilmington, Dei., a corporation of Delaware when bulked in fabric form, affords attractive fabrics hav.
Filed Sept. 27, 1961, Ser. No. 41,945 ing a soft, supple hand. A further object is to provide
8 Clairas. (C. 57-140) composite polyester yarns suitable for preparing fabrics
0 having these characteristics and possessing also the char
This is a continuation-in-part of our copending applica acteristics of resilience and crease recovery requisite for
tion Serial No. 53,224, filed August 31, 1960, and now garments suitable for wear with little or no ironing after
abandoned. Washing. A still further object is to provide such com
This invention relates to novel composite polyester posite polyester yarns having uniform dyeability char
yarns, and to fabrics prepared from such yarns, which acteristics. An additional object is to provide a process
can be caused at any desired time to become permanently for preparing such composite polyester yarns. Other ob
bulky. More particularly, the invention relates to such jects will become apparent from the following description
composite polyester yarns which exhibit a soft, supple and claims.
hand when woven into fabrics and converted to the bulk It has now been found that, in composite polyester
form. The invention is also directed to a novel process 20 yarns comprising differentially shrinkable components, the
for making the bulkable composite polyester yarns. ability of the less shrinkable component to resist shrink
It is well known that yarns formed from staple fibers, age under the influence of small restraining forces is the
and particularly from the natural fibers such as cotton and determining factor in preventing the occurrence of buck
especially wool, are more voluminous or bulky in char ling in the finished fabric. In accordance with the inven
acter than are continuous filament yarns. The bulkiness tion, therefore, the product comprises a composite linear
of the staple yarns leads to fabrics which have high cov condensation polyester yarn comprising a plurality of fila
ering power. In the case of the natural fibers, the fabrics ments of at least two species, the first filament species
are also characterized by a soft, supple hand, especially being characterized by a zero load residual shrinkage in
when the yarns are not highly twisted and dense fabric the range of 0.0% to about 20% and a residual shrinkage
constructions are avoided. Various attempts have been at 0.05 grams per denier (g.p.d.) load at least about 1.2%
made to produce a bulky continuous filament yarn in less than the Zero load residual shrinkage, and a second
order to combine the desirable aesthetic properties of filament species being characterized by a zero load re
Staple yarns with the advantages of continuous filament sidual shrinkage at least 2% higher than the zero load
yarn, such as strength and ease of processing. This has residual shrinkage of the first filament species. Yarn so
been accomplished in various ways by producing continu characterized, after being woven or knitted into fabric,
as filament yarns in which the various filaments con boiled off or scoured, and then ironed or heat set, Sur
tained in a short segment of yarn have different lengths prisingly yields bulky fabrics which have a soft, supple,
when straightened out. In one previously described staple-like hand and an attractive appearance. In con
method, two yarns which have different amounts of re trast, fabrics produced from differentially shrinkable
sidual shrinkage are associated and the resulting yarn, 40 composite polyester yarns in which the less shrinkable
or the fabric produced from it, is subjected to conditions component has a zero load residual shrinkage only slight
effective in bringing about shrinkage. As the component ly greater than the residual shrinkage at 0.05 g.p.d., up
having the greater residual shrinkage shortens to its final to about 1.2%, are buckied or puckered and have a harsh
length, the other component disposes itself outwardly hand.
from the more shrinkable component, such as by forming 45 In a preferred embodiment of the invention, where the
loops protruding from the axis of the yarn bundle. Usu coimposite polyester yarns are intended for use in dyed
aliy it is desired to convert the yarns into fabric form be fabrics, and where uniform dyeability characteristics are
fore causing them to become buiky, since bulky yarns desired, the filament species making up the composite
have a tendency to snag when they contact each other or yarn have substantially equivalent tenacities.
various parts of the yarn processing equipment, as well 50 By "residual shrinkage' as used herein and in the ap
as a tendency to be pulled out Smooth by excessive ten pended claims is meant the capability remaining or ex
sions. isting in the filament or yarn for linear contraction under
Yains composed of the linear condensation polyesters the specified tension in water at 100° C. for an exposure
have achieved high commercial success in recent years, time of 5 minutes. When the tension is not specified,
owing in part to their usefulness for garments which are residual shrinkage under zero tension is implied. The
suitable for wear with little or no ironing after washing, term "shrinkability” is also used synonymously with “re
as well as to their high strength and other characteristics. sidual shrinkage' as an attribute of a filament or yarn.
Since continuous filament yarns composed of the linear When used alone, the term "shrinkage' refers to the actual
condensation polyesters characteristically lead to fabrics Step of carrying out linear contraction of a filament or
having a smooth, cool, slick hand, attempts have been 60 yarn, or the observation of the amount of linear con
made to prepare bulkier fabrics by making composite traction, the shrinkage being carried out under zero ten
polyester yarns exhibiting differential shrinkage when sion in water at 100° C. for 5 minutes except where other
lheated. Such attempts, however, have not resulted in Wise specified. Filaments or yarns which exhibit no
fabrics exhibiting the desired characteristics of fabrics change in length when heated are regarded herein as
prepared from staple yarns; rather, the fabrics have been 65 the limiting case in which the shrinkage is zero (0.0%).
found to have an unattractive, buckled appearance and to in some cases, the filaments or yarns may be stretched
be harsh to the touch. The fabrics are thus generally un When they are heated while held under tension; in such
suitable for use in wearing apparel, and there is little or cases, the length change is regarded as shrinkage of nega
no market for such composite continuous filament poly tive value and the residual shrinkage under the specified
ester yarns. 70 load of the yarn prior to heating is correspondingly as
It is therefore an object of this invention to provide signed the appropriate negative value.
 - 3,199,281
3. 4
For the purpose of the invention, satisfactory determin truded from a single spinneret pack into parts and re
ations of shrinkage values are made as follows. To combine them to form the composite yarn after processing
measure shrinkage of the yarn at zero load, a length of each part of the filaments separately as described above.
the yarn is cut and two knots are tied in the yarn about If desired, the coherency or retentiveness of the composite
8 to 15 centimeters apart. Clamps are placed over the yarn may be improved by false-twisting it or by imparting
knots, and additional weights are hung on the yarn to a low twist to the yarn after its component parts are
make a total load of 0.05 g.p.d. so that any kinks in the brought together. Alternately, the yarn may be "inter
yarn will be pulled out and the yarn will hang straight. laced” by passing it under positive tension through a Zone
The length of the yarn between the knots is measured to of controlled fluid turbulence formed by two or more
the nearest 0.01 centimeter with a cathetometer. The 10 fluid vortices, at least one of which has an axis which is
addition weights are then removed and the sample is at least momentarily substantially parallel to the axis
hung by both clamps in 100° C. water with the yarn of the yarn, to open the yarn bundle and intermingle the
forming a free loop immersed in the water, for 2 to 5 filaments so that the yarn bundle is consolidated into a
minutes. The sample is then removed from the water compact unitary strand which maintains its unity even at
and, after the yarn has cooled, the additional weights 5 zero twist. -
are again added to make the yarn hang straight and the The novel product of the invention as well as the
length of the yarn between the knots is again raeasured. process in its various embodiments will be better under
The shrinkage is calculated in accordance with the stood by reference to the accompanying figures, in which
formula FIGURE 1 is a diagrammatical sketch or flow sheet
(Original Length-Final Length) x 100% 20 of one embodiment of the process, in which the filaments
Shrinkage = Originai Length are stretched under different conditions after they have
been spun; -
To measure shrinkage of the yarn under a load of 0.05 FIGURE 2 illustrates another process embodiment of
g.p.d., the denier of the yarn sample is determined and the invention, in which part of the extruded filaments are
an 8 to 15 centimeter sample is prepared and measured 25 forwarded from the spinneret at high speed, without Sub
to the nearest 0.01 centimeter as before. The weights are sequent stretching, while the remainder of the filaments
then adjusted so as to provide a total load on the yarn of are forwarded from the spinneret at lower speeds and sub
0.05 g.p.d., when corrected for the buoyancy of water, and sequently drawn; - -
FIGURE 3 shows a process embodiment of the inven
the sample is placed in water at 100° C. for 2 to 5 min tion in which all of the filaments are drawn and part of
utes, making sure that the sample and weight hang free 30
in the water and are completely covered by the water. the filaments are relaxed after drawing, the remainder not
The final length of the sample is measured before re being relaxed;
moving it from the water and the percentage shrinkage FIGURE 4 shows still another process embodiment of
is calculated in accordance with the above formula. the invention, in which part of the filaments are drawn
The symbol "ASoos' is employed herein to represent under one set of conditions while the remainder are drawn
the difference between the zero load residual shrinkage under a different set of conditions;
and the residual shrinkage under a load of 0.05 g.p.d. FIGURE 5 is an enlarged view of a cross section of
The value of AS.5 for a given yarn is determined by a fabric before boil-off, said fabric being woven from a
measuring the values for zero load residual shrinkage composite linear condensation polyester yarn wherein the
and residual shrinkage at 0.05 g.p.d. load in the manner 40 component filaments have different amounts of residual
shrinkage; -
described above and substituting them in the equation
FIGURE 6 is an enlarged view of a cross section, after
ASoos=Shrinkage at Zero Load boil-off, and heat setting, of a fabric having the original
appearance shown in FIGURE 5, illustrating the uniform
-Shrinkage at a Load of 0.05 g.p.d.
bulking effect achieved when the fabric of FIGURE 5 is
In accordance with the present invention the less shrink woven of the composite linear condensation polyester
able component is characterized by a ASoos value of at yarn of the invention, wherein the component filaments
least 1.2%. The ASoos value of the more shrinkable having the lesser shrinkability have a high ASoos value
component of the yarn is not a critical factor in determin (above 1.2%); and
ing the utility of the composite yarn, and ASoos values 50 FIGURE 7 is an enlarged view of a cross section, after
for the more shrinkable component are accordingly not boil-off and heat setting, of a fabric having the original
reported herein. appearance shown in FiGURE 5, illustrating the irregu
The present invention also comprehends a novel con lar structure of the boiled-off fabric when the fabric of
tinuous process for preparing the composite yarns. In FIGURE 5 is woven of a composite linear condensation
accordance with the invention, a linear condensation polyester yarn wherein the component filaments having
polyester is extruded into a plurality of filaments which the lesser shrinkability have a AS.5 value below 1.2%.
are wound up together as a yarn bundle, a first part of Turning now to FIGURE 1, one preferred embodi
the filaments being attenuated after extrusion such that ment of the process of the present invention comprises
each filament has a zero load residual shrinkage in the stretching the spun filaments under different conditions.
range 0.0% to about 20% and a residual shrinkage at 60 Filament bundles 1 and 1’, comprised of individual fila
0.05 g.p.d. load at least about 1.2% less than the zero ments 2 and 2', are obtained by separating into two
load residual shrinkage, and a second part of the filaments groups the filaments extruded from spinneret pack 3,
being attenuated after extrusion to the same final length which may be any conventional spinneret pack suitable
as the first but in a manner such that each filament has a for spinning molten condensation polyesters. The fila.
Zero load residual shrinkage at least 2% higher than the 65 ment bundles pass around forwarding rolls 4 and 4, re. .
residual shrinkage of the first part of the filaments. By Spectively, which exert tension on the extruded filaments
the term "attenuation' of a filament is meant reduction and determine the forwarding speeds F and F, respec
in its denier, not only during the spinning step as the tively (also designated as the spinning speeds). Filament
extruded molten polyester is pulled away from the spin bundle 1 is then forwarded in turn to rolls 5, 6, and 7,
neret and quenched to a solid filament, but also in any while filament bundle 1 is forwarded to rolls 5 and 7.
stretching steps which may be applied to the filament Each of the rolls may have a separator roll 3 positioned
Subsequently. If desired, two or more spinneret packs on an axis slightly skew from the plane of the axis of
may be used to Supply the filaments, which are brought the roll with which it is associated, to ensure separation
together to form the composite yarn. In practice, how of Wraps of the filament bundle around the roll. In pass
ever, it is generally preferred to divide the filaments ex 75 ing a yarn from a roll and its associated separator roll
 3,199,281
5 6
to the next element in the apparatus, the last wrap may imay be employed between the guide 12 and package 14,
terminate either on the roll or the separator roll, which or at some other convenient location.
ever is most convenient. Rolls 5 and 5' are feed rolls In accordance with the invention, the composite yarn
rotating at the same speed as forwarding rolls 4 and 4, 13 is provided as a non-bulky continuous filament yarn
respectively, while roll 6 operates at higher speed than 5 by maintaining filament bundles 1 and 1' at the same
rol 5 and roll 7 rotates at higher speed than roll 6. Simi Speed as they are brought together at guide 12 and wound
larly, roll 7 rotates at higher speed than roll 5. on package 4. This is accomplished by carrying out
In the treatment of filament bundle a, roll 5 is heated the respective attenuation processes for filament bundles
to a temperature in the range 130 to 180° C. So that the it and 1’ in accordance with the generalized relationship
filament bundle is superstretched by factors of its spun O
length without undergoing orientation while being passed windup speed=Fsdr=F's'dr (6)
from rolls 5 to 6. Such a superstretching process, in
which the filaments are attenuated under conditions which where d' is analogous to d and represents the factor by
appear to approximate plastic flow, is disclosed by Pace which filament bundle 1 may be drawn in any drawing
in his U.S. Patent 2,578,899. The factors may vary over step (separate from the Superstretching step) which may
a wide range but is usually in the range of about 1.05 to be applied. In the process embodiment just described
6. Roll 6 is maintained at a temperature in the range d=1, of course; and in a typical example of the process
of room temperature to 120° C. and the filament bundle embodiment F=F' and r"—r'= 1, reducing the relation
contacts snubbing means 9, such as a draw pin around ship to the equality sa=s'.
which the bundle is passed, between rolls 6 and 7 so that 20 Another preferred process embodiment of the inven
filament bundle 1 is drawn by a factor d of its length tion is shown in FIGURE 2, Filament bundles 1 and 1
after the superstretching step. The drawing step differs comprised of individual filaments 2 and 2' are extruded
from the superstretching step in that, in the drawing step, from spinneret pack 3. The spun filament bundle it is
the filaments are attenuated in such a manner that they passed around feed roll 5 and its associated separator roll
undergo orientation. Optionally, the filament bundle 8, into liquid bath 16 maintained at a temperature in the
may be passed over hot plate 10 between draw roll 7 and range 75-150° C., under draw pin 17 in contact with the
its separator roll to modify the residual shrinkage and bath, and around a pair of draw rolls 18. If desired,
other properties of the yarn; alternately, the draw roll guides 19 may be provided above the surface of the bath
may be heated to serve the same purpose, or the yarn between draw pin 37 and draw rolls 18 to aid in remov
may be passed over a hot plate after leaving the draw ing water from the yarn through centrifugal action. Spun
roll. The factor d is usually in the range of about 3 to 5. filament bundle i', however, is fully attenuated in the
As is well known in the prior art, the properties of the spinning step alone, being passed around rolls 18' and
drawn yarn are dependent not only on the draw ratio thence directly brought together with filament bundle 1
but also to some extent upon the temperature of drawing, at guide 2 to form composite yarn 13 wound upon pack
the spinning orientation imparted to the yarn, and other age 14. In this embodiment of the process, d'-i,
factors. S=s'=1, and r=r'= 1 in the generalized relationship
In accordance with the invention, while filament bun given above, reducing the relationship to Fa-F'. In
de is being stretched in the manner described above, practice, the peripheral speed F of rolls 18' is selected
filament bundle E is being stretched to the same final high enough to yield a spun yarn having a residual shrink
length but under different conditions. Upon leaving the age of not more than about 20%. The minimum speed
forwarding roll 4', filament bundle 1 passes to feed roll effective for this purpose will vary since the specific poly
5' heated to a temperature in the range 100 to 190 and ester composition, the polymer viscosity, and the denier
then undergoes superstretching while being passed to roll of the spun filaments also have some effect on the residual
7. The superstretching step may be carried out without shrinkage of the yarn; however, in general, the required
snubbing means and hence without orientation of the forwarding speed of rolls 18' is at least about 3,000 yards
filaments; or a modified superstretching process may be per minute. By attenuating filament bundle E' in this
used in which a moderate amount of orientation is intro way its ASoos value is maintained considerably above the
duced into the yarn by contacting the filament bundle critical limit of 1.2%. After selecting the spinning speed
between rolls 5' and 7 with means 1' for providing a F' for filament bundle 1, a draw ratio d for filament bun
moderate degree of snubbing, such as a pair of snub pins 50 dle is selected, which also fixes the spinning speed F of
between which the filament bundle is passed, as shown in filament bundle 1. The draw ratio is selected such that
FIGURE 1. After undergoing stretching, filament bundle the residual shrinkage of filament bundle 1 is at least 2%
i may be heated to reduce its residual shrinkage. This higher than the residual shrinkage of filament bundle 1.
may be done by passing the filament bundle over hot If desired, draw rolls 18 may be heated to modify the
plate 8' between draw roll 7 and its separator roll; or 55 residual shrinkage and other properties of filament bundle
alternately by heating roll 7' or by passing the yarn over i. Where rolls 8 and 8' are to be maintained at the
a hot plate after it leaves the draw roll. The temperature Saine temperature, one pair of rolls may be eliminated
in the final heating step of filament bundle ' is main by passing filament bundles and 1' around the same pair
tained sufficiently high that the residual shrinkage of fila of rolls, since the final speeds of the bundles before they
ment bundle ' is at least 2% less than that of filament 60 are brought together are the same.
bundle 1. If desired, in instances where filament bundle in a variation of the process just described with ref
i' is heated after leaving roll 7", the filament bundle may erence to FIGURE 2, filament bundle 1 is spun as before,
be allowed to relax by a factor r" of its superstretched but rolls 18 are maintained at a temperature in the
length; similarly, if desired, relaxation by a factor r of range 100 to 180 C., so that the filament bundle un
the drawn length of filament bundle i may be permitted dergoes heat Setting at constant length. In this way, the
When the filament bundle is heated after leaving roll 7. residual shrinkage of the filament bundle 1 is markedly
By processing filament bundle 1 in the manner indicated, reduced. Owing to this, the minimum spinning speed of
the AS0.05 value of the filament bundle is maintained filament bundle A' (peripheral speed of rolls 8') may be
above about 1.2%. reduced to much lower levels, if desired. Although the
After the filament bundles have been attenuated as de minimum spinning speed of filament bundle 1 is no longer
Scribed, they are brought together by means of guide 12 Critical, speeds as low as 2500 yards per minute are con
to form a composite yarn 13 which is wound up on pack sidered practicable. Of course, the spinning Speed of
age 14. If desired, means 5 for increasing the coherency filament bundle 1 is necessarily reduced also if the same
of the yarn, Such as false-twisting or interlacing means, draw ratio d is employed. A more important advantage
for this aspect of the invention, however, is that the resid
 3,199,281 3
7
ual shrinkage of filament bundle 1 may be reduced to high level. In this process embodiment Fai=F'd', while
quite low levels, approaching zero residual shrinkage. s=s'=1 and r=r's-1.
In the embodiment of the invention shown in FEGURE instead of using separate feed rolls 5 and 5' in the
3, all of the filaments are drawn, but part of the filaments process described above, a common feed roll may be used
are subsequently relaxed while the remainder are not re if the same forwarding speed is desired for both filament
laxed. After extrusion, filament bundle is passed bundles, providing that the separate identity of the fila
around forwarding roll 4 and its associated separator Toll, ment bundles is maintained. If different forwarding
around a pair of rolls 20 between which is situated a speeds are desired, a stepped feed roll having sections of
heating block. 21 curved on each side and maintained at different diameter may be employed. Similarly, other
a temperature in the range 75 to 115 C., around draw O elements in the apparatus, such as the draw bath section,
pin 22 mounted at one end of the heating block, and may be used in common where applicable providing that
thence to draw roll 7. Filament bundle ' is similarly separate identity of the filament bundles is maintained
passed from forwarding roll 4' around feed rolls 20' and until no longer required. -
heating block 2' to draw pin 22 and draw roll 7'. How In the above discussion, the various process embodi
ever, between draw roll 7 and guide 12 where filament 5 ments of the invention are described in terms of spinning
bundles 1 and 1 are brought together, filament it is the filaments and then subjecting them to the various
passed through a relaxing jet 23 wherein it is exposed to Superstretching, drawing, and relaxing treatments in a
hot gas or liquid. Instead of the relaxing jet, a hot plate continuous manner, without interrupting the process to
or other relaxing means may be employed. Composite wind the filament bundles one or more times. Extrusion
yarn 13 formed from filament bundles 1 and 1' is then 20 of the filament bundles preferably from the same spin
wound on package 14, first being passed if desired neret, followed by continuous processing of the separated
through interlacing jet 15 or other means for increasing bundles and subsequent recombining of the bundles to .
the coherency of the yarn. In this process embodiment, form the composite yarn without intermediate winding
s=s's 1 and usually r-1, so that Fal-Fai'i'. Cfccurse, operations is the preferred manner of carrying out the
the drawing and relaxing conditions for filament bundle 25 process. However, if desired, the process may be carried
1 must be adjusted such that the AS.05 value of the filia out in a sequence of individual operations with inter
ments is greater than about 1.2%. This is readily accom mediate winding steps.
plished; in a typical example F=182 y.p.m., F=262 The novel character of the composite polyester yarn
y.p.m., d=3.3, d'=2.75, and r=0.833, the temperatures of the invention, as contrasted with other composite poly
of the heated blocks being 100 C. for both filament bun 30 ester yarns, is illustrated in FIGURES 5 through 7. The
dies, and air at 40 p.si.g. and 320° C. being used in the figures represent fabric cross sections taken parallel to
relaxing jet. The residual shrinkage of filament bundle the warp, with the filling seen in section. FIGURE 5
1 is lower than that of filament bundle when the yarn shows an enlarged view of a cross section of a fabric
- is made in this way, and the level of residiual shrinkage before boil-off, said fabric being woven from a composite
as well as the AS.5 level of filament bundle E are readily linear condensation polyester yarn wherein the com
adjusted by varying the process conditions. - ponent filaments of the yarn have different announts of
In a variation of the process just described with refer residual shrinkage. As shown in the figure, the fabric
ence to FIGURE 3, draw pin 22' is omitted. This allows has the appearance of a conventional fabric woven from
for increased relaxation, resulting in higher A.So.05 values synthetic continuous filament yarn. This appearance is
for filament bundle 1. 40 characteristic of the fabric whether it is woven from the
In still other variations of the process shown in FIG novel composite yarn 3 of the invention comprised of
URE 3, feed rolls 20', heating block. 21, draw pin. 22, shrinkable filaments 2 together with filaments 2' having a
and relaxing jet 23’ may all be omitted; while draw Ioll lesser residual shrinkage as well as a high ASoos value or
7' is heated or the yarn is heated just before reaching the woven from a composite linear condensation polyester
roll by passing it through a jet tube wherein it is exposed yarn 33 (numeral indicated parenthetically in FIGURE
to hot gas or liquid. The residual shrinkage of filament 5) comprised of the same shrinkable filaments 2 together
bundle 1 is thereby kept lower than that of filament bun with filaments 32 (numeral indicated parenthetically in
dle and the AS.5 value of filament bundle i' is main FIGURE 5) having the same low residual shrinkage as
tained at a high level. In these process variations the filaments 2', but a ASoos value below 1.2%. Prior to
factors s, s', r, and r are all equal to unity, so that 50 boil-off, filaments 2 and 2 (as well as filaments 2 and 32)
Fd-F'd. - are substantially identical in appearance. -
Still another embodiment of the process of the invention FIGURE 6 illustrates the appearance of the cross sec
is illustrated in FIGURE 4. As in FIGURE 2, the spun tion, after boil-off and heat setting at 196° C., of a fabric
filament bundle. is passed around feed roll 5 and its woven from the novel composite yarn 3 of the invention
associated separator rol. 8, into liquid bath 16 main wherein the component filaments 2 of lesser shrinkability
tained at a temperature in the range 75-150 C., under have a high AS0.05 value, and having the original appear
draw pin 17 in contact with the bath, and around guides ance shown in FIGURE 5. As shown in the figure, fila
19, after which it is passed several times around the com ment bundle E. composed of individual filaments 2 and
bination of heated roll 25, and its associated unheated filament bundle A' composed of individual filaments 2', are
now identifiable, owing to the higher shrinkage of filament
separator roll 8. Spun filament bundle 1 is passed around 60 bundle E. Owing primarily to the contraction of filament
feed roll 5 and its associated separator roll 8, under draw
bundle A, fabric shrinkage has occurred (reduced distance
pin 17 in contact with bath 16', around guides 59', and . between
then several times around the pair of heated draw rolls filling ends in the figure). Filament bundle E,
24 and 25. In the embodiment shown in FIGURE 4, because of its lesser shrinkage, has disposed itself out
roll 25 is used in common by filament bundles i and , 65 wardly in loops, which are seen not only in the warp but
but the identity of the bundles is maintained until they in the filling in cross section (note filaments 2 in cross
are brought together at guide 2 to form composite yarn. Section); such loops are 3-dimensional, of course, al
13 wound upon package 14. The temperature of fila though indicated as being in the plane of the paper. It
ment bundle. at the draw rolls 24 and 25 is substan is to be noted that the loops formed by filament bundle E.'
tially higher than that of filament bundle 1, since the 70 are relatively uniform, occurring between each adjacent
former is wrapped around two heated rolls, while the pair of cross-over points in both the warp and the filling.
latter is wrapped around one heated and one unheated The boiled-off and heat-set fabric shown in section in
roll. The residual shrinkage of filament bundle E is FIGURE 6 is characterized by a soft, supple hand and
thereby kept lower than that of filament bundle and a high degree of opacity and cover owing to its uniform
the ASoos value of filament bundle 1 is maintained at a bulkiness.
 3,199,281
FIGURE 7 illustrates the appearance of the cross sec prepared from the composite yarns of this invention to
tion, after boil-off and heat setting at 196 C., of a fabric give a smooth and uniform appearance after dyeing.
having the original appearance shown in FIGURE 5, but composite polyester yarns made up of species having dif
woven from a composite linear condensation polyester ferent shrinkage characteristics and having a tenacity ratio
yarn 33 wherein the component filaments 32 having the 5 failing outside of the range 0.7 to 1.1 do not give lini
lesser shrinkability have a AS.5 below 1.2%. Although formly dyed fabrics. Rather, dyed fabrics produced from
shrinkable filaments 2 and filaments 32 of lesser shrink such yarns exhibit a distinct moiré or heather effect.
ability are substantially identical in appearance prior to For white goods, of course, the tenacity ratio is unin
boi-off and heat-setting, as shown in FIGURE 5, fila portant.
ment bundle 1 comprised of filaments 2 and filament 10 The term “tenacity” as used herein refers to the tensile
bundle 33 comprised of filaments 32 are readily identi stress required to break a filament or yarn, expressed
fiable after boil-off since the latter has disposed itself in terms of force per unit linear density, as grams per
outwardly in loops from the axis of the yarn bundle 33. denier or grams per tex. The measurement of tenacity
In contrast to the small uniform loops formed between is well known in the textile art and many suitable methods
each cross-over point by filament bundle i' shown in 5 are available for such determinations.
FIGURE 6, however, filament bundle 3 forms large Once the relationship between tenacity and dyeability
loops between certain cross-over points without dissociat is recognized, the preparation of composite polyester yarns
ing itself from filament bundle 1 between most of the having differential shrinkage characteristics and equiva
cross-over points. As indicated in the figure, there is a lent dyeability may be carried out in any of a number
tendency for all of the filaments to loop out at the same 20 of ways as will be illustrated in the specific examples pre
point, even when they are not twisted together. The sented herein. The uniform dyeability achieved by sub
boiled-off and heat-set fabric shown in section in FIG stantially matching the tenacities of the different filament
URE 7 is characterized by a harsh hand and has a species is not limited to one class of dyes. Any class of
“buckled' appearance owing to the presence of the loops. dyes Suitable for dyeing polyester fibers may be used.
It is believed that the formation of large, infrequent 25 Suitable dyes include dispersing dyes, cationic dyes, and
loops by filament bundle 31, rather than small, uniform anionic dyes. Dispersed dyes are generally used for uin
loops between each cross-over point, is attributable to the modified polyesters whereas cationic dyes may be used for
stiffness of filaments 32 even when heated, although this polyesters modified with sulfonate sait groups as disclosed
statement is not intended to be taken as limiting. In in Belgian Patent 562,460, and anionic dyes may be used
accordance with the invention, an inverse correlation has 30 for polyesters modified with linking units containing
been observed between the ASoos value and the stiffness tertiary annine groups and the like.
of the filaments, the critical ASoos value being about 1.2%. The novel yarn of the invention is composed of a syn
When the novel composite polyester yarns of this in thetic fiber-forming inear condensation polyester. By
weiition are intended to be incorporated in fabrics which "linear condensation polyester' is meant a linear polymer
are subsequently dyed, it is important that the different 3.5 comprised of recurring structural units containing, as an
species of filaments making up the composite yarn have integral part of the polymer chain, recurring carbonyloxy
matched dyeability characteristics. It would be expected groups
that filaments having sufficient internal structural differ
ences to give the shrinkage differences necessary for the O
yarns of this invention would inherently possess a differ 40
ence in dyeability, and this is generally true. Surprisingly,
however, it has been discovered that by choosing filament and having a relative viscosity of at least about 8 in a
Species having substantially equivalent tenacities, this dye Solution of 11 g. of the polymer in 103 cc. of a mixed
ability difference can be eliminated. solvent composed of 58.8 parts by weight of phenol and
Prior theories relating to the dyeability of synthetic 41.2 parts by weight of trichlorophenol. Preferably, at
polyester fibers have taught that degree of crystallinity 45 least about 75% of the recurring structural units of the
is the major factor controlling dye uptake. Following polyester are derived from a glycol containing 2 to 12
these theories, it would have been expected that dyeing carbon atoms and a dicarboxylic acid selected from the
differences between fibers of different shrinkages could be group consisting of terephthalic acid and the naphthalic
eliminated by choosing fibers of the same degree of crys acids. The polyesters may be prepared by reacting the
tallinity. However, present experimental facts are in 50 dicarboxylic acid or an ester-forming derivative thereof
compatible with this viewpoint. Rather, it has been with an excess of a glycol, G(OH)2, where --G- is a
found, as a part of this invention, that the major factor divalent organic radical containing from 2 to 12 carbon
controlling dye uptake is the degree of orientation of the atoms and attached to the adjacent oxygen atoms by satu
nlolecules in the amorphous areas of the fiber. A con rated carbon atoms, or an ester-forming derivative of the
venient measure of "amorphous orientation' is fiber te 55 glycol. Following the preparation of the monomeric
nacity. ester, polycondensation is carried out at elevated tern
Furthermore, it has been discovered that in critical perature and reduced pressure with elimination of excess
color shades with dispersed dyes commonly used for glycol. Examples of suitable glycols include ethylene
polyester fibers, a very uniformly dyed fabric is obtained glycol, diethylene glycol, butylene glycol, decamethylene
if the high shrinkage filament species is one which accepts 60 glycol, and cis- trans-p-hexahydroxylylene glycol. Mix
dyes a little more readily than the low shrinkage species. tures of Such glycols may suitably be used to form copoly
This phenomenon is thought to be due to the fact that esters, or small amounts, e.g., up to about 15 rao: per
upon expesure to the heat of the dye bath, or upon ex cent, of a higher glycol may be used, such as a polyethyl
posure to heat previous to dyeing, the high shrinking fila ene glycol. The acid component of the polyester prefer
ment species retreats to the interior of the yarn bundle ably consists of at least 75% of terephthalic acid or a
and thereby becomes less accessible to the dye bath. In naphthalic acid, especially 2,6-naphthalic acid or 2,7-
any case, it has now been found that composite polyester naphthalic acid. Similarly, copolyesters may be formed
yarns of uniform dyeability are obtained when the numeri by replacing up to about 25 mol percent of the terephthalic
cal value of the ratio of the tenacity of the high shrink naphthalic acid or derivative thereof with another di
age component to that of the low shrinkage component 70 carboxylic acid or ester-forming derivative thereof, such
is 0.90--0.20. In other words, the tenacity ratio as adipic acid, dimethyl sebacate, isophthalic acid, hexa
high shrinkage species hydroterephthalic acid, or sodium 3,5-dicarbomethoxy
low shrinkage species benzenesulfonate. The copolyester may also be formed
by replacing part of the terephthalic or naphthalic acid or
should fall in the range 0.70 to 1.10 in order for fabrics derivative thereof with a hydroxy acid or derivative there
 3,199,281,
1. - - - 2
of, such as p-(2-hydroxyethyl) benzoic acid or methyl The oven is 12 inches long and the allowed shrinkage in
p-(2-hydroxyethoxy) benzoate. Linear terephthalate or the oven is 17.2%. The yarn has a denier of 33 (3.7 tex),
naphthalate polyesters and copolyesters are especially suit a tenacity of 3.0 g.p.d., an elongation of 30%, a boil-off
able for use in the present invention since they have high shrinkage of 2.9%, a yield point of 1.0...g.p.d., an initial
melting points and since the crystallinity and orientation nodulus of 69.g.p.d., and a ASoos value of 4.45%.
of filaments formed from thern may be readily controlled - Yarn "D' is drawn by passing the yarn from a feed
over a wide range. The different filament species of the roll operating at a peripheral speed of 132 y.p.m. to a
composite yarn of this invention may be formed from the draw pin (1 wrap). 1.6 inches in diameter maintained at a
same polyester or from different polyesters. A preferred temperature of 100 C. and thence to a draw roll operat
polyester is a copolyester containing 0.5 to 3.5 mol per 10 ing at 454 y.p.m., after which it is wound at the same
cent sodium 3,5-dicarbomethoxybenzenesulfonate, or an speed. The draw ratio is 3.451. The yarn has a denier of
equivalent sulfonate salt-containing moiety, as described in 31 (3.4 tex), a tenacity of 3.3 gp.d., an elongation of
Belgian Patent 562,460. 21%, a boil-off shrinkage of 9.2%, a yield point of 1.9
The following examples will serve to illustrate the y.p.d., and an initial modulus of 104 g.p.d.
invention further, although they are not intended to be 5 Yarns 'A' and “B” are then combined through an
limitative. interlacing jet to form a composite yarn having a tenacity
EXAMPLE 1. ratio of 0.35. A 1 x 1 plain weave fabric containing 90
ends per inch in the warp (77, twist) and 84 ends per inch
Polyethylene terephthalate having a relative viscosity in the filling 37, twist) is then prepared from the yarn.
of 25.5 and containing 0.3% TiO2 is spun at 295 C. 20 Frior to boil off, the fabric has the smooth, slick hand
through a spinneret having 17 Y-shaped orifices formed characteristic of continuous filament synthetic fabrics.
by the intersection of 3 slots, each 0.007 inch in length However, when the fabric is immersed in water at 100°
and 0.004 inch in width. The yarn is wound up at a C. for 5 minutes, dried, and ironed, the yarn comprising
speed of 1206 y.p.m. and is found to have a spun denier the fabric becomes quite bulky, and the hand of the fabric
of 110 (12.2 tex). The spun yarn is then used as a com becomes warm and soft. The fabric has a weight of 2.2
mon supply for preparing yarns “A” and “B” as de oZ./sq. yd. and a specific volume of 2.4 cc./g. The spe
scribed below. In another experiment, polyethylene cific volume is determined by dividing the volume of the
terephthalate having a relative viscosity of 15.0 and con fabric by its weight; the volume of a fabric sample of
taining 0.3% TiO2 is spun at 278 through a spinneret known area being determined by multiplying the area by
having 15 Y-shaped orifices formed by the intersection 30 the thickness measured under a pressure of 3.4 p.s. i. in
of 3 slots, each 0.007 in length and 0.004 inch in width. accordance with method D76-53 of the A.S.T.M. Stand
The yarn, which is designated below as yarn "C' is wound ards on Textile Materials. The fabric has an attractive
up at 1200 y.p.m. and is found to have a denier of 109 appearance with no trace of buckling.
(12.1 tex). In still another experiment, a yarn designated Similarly, yarns "C" and "D" are combined through an
below as yarn "D' is spun under the same conditions as 3 5 interlacing jet to form a composite yarn having a tenacity
yarn "C," except that the spun denier is 108 (12.0 tex).
giv 22 ratio of 1.10. A 1 x 1 plain weave fabric containing 93
Yarn "A' is drawn and relaxed in accordance with a ends per inch in the warp (7Z twist) and 76 ends per
modification of the process described with reference to inch in the filling (3Z twist) is prepared from the yarn.
filament bundle of FIGURE 3. The yarn is passed from 40 When the fabric is immersed in water at 100° C. for 5
a feed roll around heated block. 21" (5% wraps), which minutes, dried, and ironed, the yarn comprising the fabric
is maintained at 88 C. The yarn is then passed directly becomes quite bulky, and the hand of the fabric becomes
to draw roll 7', without a draw pin being used in this Warm and soft. The fabric has a weight of 1.8 oz./sq.
instance. The speed of the yarn at the draw roll is 750 yd. and a specific volume of 2.5 cc./g. The fabric has an
y.p.m. and the draw ratio is 3.77. The yarn is then passed attractive appearance with no trace of buckling.
through a relaxing jet 4' in length supplied with air at 45 Samples of the two fabrics are dyed at the boil to a
40 p.s.i.g. and 360° C., after which it is wound up at 634 medium blue shade with the dispersed dye 1-(p-ethyl
y.p.m. The yarn is accordingly relaxed 15.3% between olanilino) 4,5-dihydroxy-8-nitroanthraquinone using 5
the draw roll and the windup. The drawn and relaxed grains per liter of o-phenylphenol as a carrier. The re
yarn has a denier of 35 (3.9 tex), a tenacity of 4.0 Sulting dyed fabrics are quite uniform in appearance, giv
ing no evidence of heather or moiré effect. .
g.p.d., an elongation of 30%, a boil-off shrinkage of
4.2%, a yield point of 0.8 g.p.d., an initial modulus of 61 . Similar results are obtained by preparing composite
g.p.d., and a ASoos value of 5.0%. - yans as described above, substituting polyethylene ter
Yarn 'B' is drawn in accordance with the process de ephthalate/isophthalate (8.5/15) for polyethylene ter.
scribed with reference to filament bundle of FIGURE 3. ephthalate in the preparation of yarns “C” and “D.”
The yarn is passed from a feed roll arcund heated block EXAMPLE 2.
2 (7 wraps) maintained at 110° C., passed once around
a 346 inch draw pin, and thence to draw roll 7 which is Polyethylene terephthalate having a relative viscosity
operated at a peripheral speed of 634 y.p.m., after which of 30 and containing 2% TiOa is spun at 300° C. through
the yarn is wound up at the same speed. The draw ratio a Spinneret having 34 triangular orifices, each 0.012 inch
is 3.20. The yarn has a denier of 35, a tenacity of 3.4 60
on a side. The extruded filaments are separated into two
g.p.d., an elongation of 30%, a boil-off shrinkage of bundles of 17 filaments each and processed continuously
14.5%, a yield point of 2.0 g.p.d., and an initial modulus in accordance with the process shown in FIGURE 2.
of 89 g.p.d. One bundle of spun filament is taken up by a feed rol1 op
Yarn “C” is drawn in accordance with a modification erating at a peripheral speed of 890 y.p.m., passed un
of the process described with reference to filament bundle der a draw pin immersed in a bath of water maintained
of FGURE 3. The yarn is passed from a feed roll
around a heated block 21' (5 wraps) maintained at 90° at 90° C., and passed out of the bath via a pair of guides
C. The yarn is then passed directly to draw roll 7 oper as shown in FIGURE 2 to a pair of draw rolls main
ating at a peripheral speed of 150 y.p.m. after which the tained at a temperature of 160°C. (contact time on rolls
yarn is wound up at the same speed. No draw pin is used. 0.063 second) and operating at a peripheral speed of 2800
The draw ratio is 3.494. The drawn yarn is passed from y.p.m. The draw ratio is accordingly 3.146. The other
a roll operating at a peripheral speed of 180 yp.m. into filament bundle is passed directly from the spinneret to a
an oven containing steam at 100° C. and at atmospheric pair of rolls maintained at a temperature of 160° C.
pressure and is passed out of the oven and wound up on a (contact time on rolls 0.124 second) and operating at a
package operating at a peripheral speed of 149 y.p.m. peripheral speed of 2800 y.p.m. The two filament bun
 3,199,281
3 4.
dies are passed from the hot rolls to a guide where they a temperature of 96° C. and thence to a draw roll op
are combined into a single composite yarn, passed erated at 454 y.p.m., finally being wound up. The draw
through an interiacer, and wound up on a yarn package. ratio is 2.7. The yarn, identified as yarn “I, has a
At the end of the experiment, the filament bundles are denier of 40 (4.4 tex), a tenacity of 3.6 g.p.d., an elonga
collected separately to measure their separate yarn prop 5 tion of 25%, a yield point of 1.8 g.p.d., a boil-off shrink
erties. The filament bundle drawn in the water bath is age of 12.0%, and an initial modulus of 91 g.p.d.
found to have a denier of 34 (3.8 tex), a tenacity of 3.7 Yarns 'E' and “I” above are combined to form a com
g.p.d., an elongation of 26%, a yield point of 2.6 g.p.d.; posite yarn with a tenacity ratio of 2.0 which is twisted
a boil-off shrinkage of 11.6%, and an initial modulus 5 turns per inch (Z) for the warp and 3 turns per inch
of 85 gp.d. The filament bundle wound directly on the 10 (Z) for the filling of a 1 x 1 plain weave fabric contain
hot rolls has a denier of 32 (3.6 tex), a tenacity of 2.5 ing 96 ends per inch in the warp and 90 in the filling.
g.p.d., an elongation of 62%, a yield point of 0.9 g.p.d., The fabric is boiled off, dried, and ironed. It has a soft,
a boil-off shrinkage of 3.8%, an initial modulus of 52 supple hand and exhibits a specific volume of 2.5 cc./g.
g.p.d., and a ASoos value of 2.8%. A 1 x 1 plain Weave and a weight of 2.09 oz./sq. yd. The fabric has an at
fabric containing 86 ends per inch in the Warp (77. tractive appearance with no evidence of buckling.
twist) and 84 ends per inch in the filling (3Z twist) is A sample of the fabric is dyed at the boil with the dis
then prepared from the composite yarn. The fabric is persed dye 1-(p-ethylolanilino) 4,5-dihydroxy-8-nitro-an
then immersed in water at 100° C. for 5 minutes, dried, thraquinone in the presence of o-phenylphenol as a car
and heat set at 200° C. for one minute. The resulting rier, and it is found that the two species of filaments dye
fabric exhibits a specific volume of 2.60 cc./g. and a 20 at a different rate. The dyed fabric possesses a distinct
weight of 1.98 oz./sq. yd. It has an attractive appearance moiré because of this nonuniform dyeability.
with no evidence of buckling.
The experiment is repeated, using a spinneret contain EXAMPLE 4
ing 68 round holes, each 0.009 inch in diameter and A series of yarns of low residual shrinkage, identified
separating the filaments into two bundles of 34 filaments hereinafter as yarns "F,” “G,' and "H' and a series of
each. The feed roll for the drawn yarn is operated at a yarns of high residual shrinkage, identified hereinafter as
peripheral speed of 930 y.p.m. and the hot draw rolls at yarns “5,” “K,” and "L" are prepared separately as fol
2780 y.p.m., the draw ratio being 2.989 and the contact lows:
time of the yarn on the heated roil 0.085 second. The Polymer used and spinning conditions.-Yarns “F” and
hot rolls for the high-speed spun filament bundle are cor 30 “J” are prepared from polyethylene terephthalate/5-(so
respondingly operated at 2780 y.p.m. During most of dium sulfo) isophthalate (98/2) containing 2% TiO.
the run the two filament bundles are combined as a corn Polymer having a relative viscosity of 18.1 is used for yarn
posite yarn as indicated above, but individual samples of “F” and polymer having a relative viscosity of 19.5 is used
the filament bundies are also collected. The drawn yarn. for yarn "...' The yarns are spun separately at 296 C.
is found to have a denier of 76 (8.4 tex), a tenacity of 3.5 from a spinneret containing 17 round holes, each 0.009
4.4 g.p.d., an elongation of 34%, a yield point of 3.5 inch in diameter, and wound up at 1500 y.p.m.
gip.d., a boil-off shrinkage of 10.5%, and an initial Yarns “G.,” “H,” “K,” and “L” are prepared from poly
modulus of 61 g.p.d. The high-speed spun filament ethylene terephthalate containing 2% iC and having a
bundle is found to have a denier of 70 (7.8 tex), a relative viscosity of 25.5. Yarns "G” and “K” are spun
tenacity of 2.5 g.p.d., an eiongation of 114%, a yield 40 separately at 296 C. from a spinneret containing 17
point of 1.0 gp.d., a boil-off shrinkage of 3.0%, an initial round holes, each 0.009 inch in diameter, and wound up
modulus of 34 g.p.d., and a ASoos value of 3.5%. A at 1206 y.p.m. Yarns "H" and "L' are spun separately
1 x 1 plain weave fabric containing 68 ends per inch in at 296 C. from a spinneret containing 17 triangular
the warp (7Z twist) and 64 ends per inch in the filling holes, each 0.012 inch on a side, and wound up at 1000
(3Z twist) is prepared from the composite yarn and y.p.m. (yarn “H”) and 1500 y.p.m. (yarn “L”).
boiled off, dried, and heat set at 200 C. for one minute. Superstretching the low residual shrinkage yarns.-
It exhibits a specific volume of 2.29 cc./g. and a weight Yarns “F,” “G,” and “H,” each of which has an as-spun
of 3.6 cz./sq. yd. The fabric has an attractive appear denier of 240 (26.6 tex), are superstretched in a single
ance with no trace of buckiing. stage superstretching apparatus of the type described with
EXAMPLE 3 reference to filament bundle A' of FIGURE 1. The yarns
are passed around a feed roll maintained at 165 C. --5,
Polyethylene terephthalate/5-(sodium sulfo)iscphthal between a pair of snub pins, over a hot plate maintained
ate (99/1) containing 0.3%. TiO2 and having a relative at 143° C. --3, around a draw roll, and are then wound
viscosity of 26.5, prepared from ethylene glycol, dimethyl on a yarn package. The stretch ratio is 6.048 in each case
terephthalate, and 1 mol percent (base on the dimethyl 55 and the drawing speeds and hot plate contact times are
tereighthalate) of sodium 3,5-dicarbonnethoxybenzenesul as follows: “G. 750 y.p.m. and 0.178 second; “F” and
fonate, is spun at 295 C. through a spinneret having 34 “H,” 454 and 0.294. The properties of the superstretched
round holes, each 0.009 inch in diameter. The extruded yarns are summarized in Table 1.
filaments are taken up by a roll (room temperature) op Drawing the high residual shrinkage yarns.-Yarns
erating at a peripheral speed of 3400 y.p.m. and are then 60 “J” and “K” have deniers as spun of 120 (13.3 tex), while
wound up. The yarn has a denier of 35 (3.9 tex), a yarn “L” has an as-spun denier of 109 (12.1 tex). Each
tenacity of 1.8 g.p.d., an elongation of 55%, a yield of the yarns are passed from a feed roll to a draw pin
point of 1.1 g.p.d., a boil-off shrinkage of 3.7%, an ini (2 wraps) 1.6 inches in diameter maintained at 100 C.
tial nodulus of 53 g.p.d., and a ASoos value of 2.6%. -2 and then to a draw roll operated at 454 y.p.m.,
This yarn is identified as yarn "E" below. 65 finally being wound up. The respective draw ratios are:
In another spinning run, polyethylene terephthalate/5- “i,” 2.769; “K, 3.353; and “L” 2.969. The properties of
(sodium sulfo) isophthalate (98/2) containing 0.3% the drawn yarns are summarized in Table 1.
TiO, and having a relative viscosity of 19 is spun at 295 Fabric preparation.-Composite yarns are prepared by
C. through a spinneret having 27 round holes, each 0.009 combining yarns “F” and “J,” “G” and “K,' and “H” and
inch in diameter, and the yarn is wound up at a speed of 70 “L, respectively. The composite yarns are twisted 7
1200 y.p.m. The yarn as spun is found to have a denier turns per inch (Z) for the warp and 3 turns per inch (Z)
of 108 (12 tex). The spun yarn is then passed from a
for the filling of 1 x 1 plain weave fabrics having the num
ber of ends per inch in warp and filling indicated in
feed roll operating at a peripheral speed of 168 y.p.m. to a Table 1. The properties of the fabrics after boil-off and
draw pin (2 wraps) 1.6 inches in diameter maintained at ironing are also indicated in the table.
 3,199,281
s ES
TABLE 1-YARN & FABRIC PROPERTIES 1206 yip.m. The yarn as spun is found to have a denier
of 120 (13.3 tex). The spun yarn is then passed from a
Yards
feed roll operating at a peripheral speed of 149 y.p.m. to
A. Yarn Properties a draw pin (1 wrap) 1.6 inches in diameter maintained at
5 a temperature of 100° C. and thence to a draw roll oper
iFi. G' ated at 454 y.p.m., after which it is wound up at the same
speed. The draw raito is 3.049. The yarn, identified as
TDenier-------------------------
TeX-----------
39
4.3
41
4.6
40
4.4
43
4.8
37
4.
39
4.3 yarn “P,” has a denier of 40 (4.4 tex), a tenacity of 3.9
Tenacity, g.p.d.---- 1.6 1.9 2.4 2.9 4, 1 3.. 6 g.p.d., and elongation of 26%, a yield point of 1.3 g.p.d.,
Elongation, percent
YiE. g-p.d.-------------- 10 : 0.7
72 108 69 35
0.9 - 2.4
23
3.5 .
28
O a boil-off shrinkage of 11.5%, and a modulus of 81 g.p.d.
Boil-off shrinkage, percent 4.4 3.5" 3.9 11.1.0. 6- . 11. A portion of this yarn, identified below as yarn "Q,” is
Initial modulus, g.p.d.---------- sa : s 84 124 94. then heated on a yarn package (heated at constant length)
AS0.05 value, percent.----------- in an oven at 140° C. for 12 hours. Yarn “Q' is found to
have a denier of 40, a tenacity of 3.9, an elongation of
26%, a yield point of 1.3, a boil-off shrinkage of 1.1%,
an initial modulus of 81 gp.d., and a ASoos value of
Fabrics Prepared From Desig 0.75%.
- -
B. Fabric Properties
nated Composite Yarns in another spinning run, yarn is spun in the same
i F-4J G - K -- 'I''
manner described above for yarn “P,' except that the
20 denier of the yarn as spun is 240 (26.7 tex). This yarn,
designated below as yarn "R," is superstretched in a sin
Ends per inch, warpffiling-------
Specific volume, cc.fg---
90/72
2.31
80/60
2.88.
78/84
2.52 gle stage superstretching apparatus of the type similar to
Weight, Oz.fsq. yd-------- - - - - -2.7 2.03 2.32 that described with reference to filment bundle 1 of
Buckling exhibited by fabr None None None FIGURE 1. The yarn is passed around a feed roll (sin
gle wrap) maintained at 165 C., between a pair of snub
pins (48 wrap angle), around a draw roll maintained
EXAMPLE 5 at 140° C. and equipped with a separator roll (5 wraps),
and is then wound on a yarn package. The drawing
speed is 454 y.p.m. The stretch stretch ratio is 6.048,
Polyethylene terephthalate having a relative viscosity 30 and the contact time of the yarn on the on hot draw roll
of 15 and containing 0.3% TiO2 is spun at 278 C. is 0.294 second. Superstretched yarn "R" has denier of
through a spinneret having 15 Y-shaped orifices formed 35 (3.9 tex). a tenacity of 2.1 g.p.d., an elongation of
by the intersection of 3 slots, each 0.007 inch in length 93%, a yield point of 0.8 g.p.d., a boil-off shrinkage of
and 0.004 inch in width. The yarn is wound up at a speed 2.6%, an initial modulus of 52 g.p.d., and a ASoos value
of 1200 yards per minute and is found to have a spun 35 of 3.5%. -
denier of 180 (12 tex). The spun yarn is then used as a Yarns “P” and “Q' are then piled together to form a
common supply for preparing yarns “M” and "N" as de composite yarn. A 1 x 1 plain fabric containing 90
scribed below. ends per inch in the warp (77, twist) and 72 ends per inch
Yarn “M” is passed from a feed roll (1 wrap) operating in the filling (3Z twist) is then prepared from the yarn.
at a peripheral speed of 145 y.p.m. and maintained at 40 Prior to boil-off, the fabric has the smooth, slick hand
118° C. to a draw roll operated at a peripheral speed of characteristic of continuous filament synthetic fabrics.
454 y.p.m., after which the yarn is wound up at the same When the fabric is immersed in water at 100° C. for 5
speed. No draw pin is used in this experiment, and the minutes, dried, and ironed, the yarn comprising the fab
yarn is not relaxed. The draw ratio is 3.140. The drawn ric becomes bulky; however, the hand of the fabric
yarn has a denier of 34 (3.8 tex), a tenacity of 1.7 g.p.d., 45 becomes rather harsh, and the fabric has an unattractive
an elongation of 43%, a boil-off shrinkage of 3.6%, a appearance with severe buckling being exhibited. The
yield point of 0.9 g,p.d., an initial modulus of 58 g.p.d., specific volume of the fabric is 1.9 cc./g. w
and a ASoos value of 3.75%. - Yarns “P” and “R” are similarly plied together to form
Yarn “N is passed from a feed roll operating at a pe a composite yarn. A 1 x 1 plain weave fabric contain
ripheral speed of 132 y.p.m. to a draw pin (1 Wrap) 1.6 ing 90 ends per inch in the warp (77 twist) and 30 ends
inch in diameter maintained at a temperature of 100 C. per inch in the filling (32, twist) is prepared from the
and thence to a draw roll operated at a peripheral speed yarn. Prior to boil-off, the appearance and hand of this
of 454 y.p.m., after which the yarn is wound up at the fabric are similar to the appearance and hand of the
same speed. The draw ratio is 3.451. The drawn yarn fabric prepared from plied yarns “P” and "Q,” above.
has a denier of 31 (3.4 tex), a tenacity of 3.3g.p.d., an 55 When the fabric prepared from yarns “P” and “R” is
elongation of 21%, a boil-off shrinkage of 9.2%, a yield immersed in water at 100° C. for 5 minutes, dried, and
point of 1.9 g p.d., and an initial modulus of 104 g.p.d. ironed, the yarn comprising the fabric becomes bulky,
Yarns “M” and “N' above are combined through an and the hand of the fabric becomes warn and soft. The
interlacing jet to form a composite yarn. A 1 X 1 plain fabric has an attractive appearance, with no trace of
weave fabric containing 93 ends per inch in the warp (77. 60 buckling being exhibited. The fabric has a specific vol
twist) and 76 ends per inch in the filling (3Z twist) is then ume of 2.3 cc./g. -
prepared from the yarn. After the fabric is boiled off, EXAMPLE 7
dried, and ironed, the yarn comprising the fabric becomes
bulky and the hand of the fabric becomes warm and soft. Polyethylene terephthalate/5 - (sodium sulfo) iso
The fabric has a weight of 1.9 oz./sq. yd. and a specific 65 phthalate (98/2) containing 0.3% TiO2 and having a rela
volume of 2.76 cc./g. It has an attractive appearanc tive viscosity of 19 is spun at 295 C. through a spin
with no trace of buckling. neret having 34 Y-shaped orifices formed by the inter
section of 3 slots, each 0.007 inch in length and 0.004
EXAMPLE 6 inch in width. The extruded filaments are separated into
70 two bundles of 17 filaments each and are proccessed con
tinuously in accordance with the process shown in FIG
Polyethylene terephthalate containing 0.3%, TiO, and URE 4, except that a common feed roll and drawing ap
having a relative viscosity of 25.5 is spun at 296° C. paratus are used to process the two bundles, maintaining
through a spinneret having 17 round holes, each 0.009 the separate identity of the filament bundles. The feed
inch in diameter, and the yarn is wound up at a speed of rolls is operated at a peripheral speed of 980 y.p.m. and
 3,199,281
7 8
an 0.5-inch draw pin partially immersed in 90 C. aque EXAMPLE 9
ous bath is employed. The filament bundles are passed
under the draw pin and thence out of the bath via a Polyethylene terephthalate containing 0.1% TiO2 and
pair of guides, after which one of the filament bundles, having a relative viscosity of 25.5 is spun at 295 C.
identified as filament bundle "0." is passed around a 5 through a spinneret having 14 round holes, each 0.009
pair of draw rolls operating at a peripheral Speed of 2750 inch in diameter. The yarn is wound up at a speed
y.p.m. and maintained at a temperature of 180°C. of 1400 y.p.m. and is found to have a spun denier of
The other filament bundle, identified as filament bun 238 (26.4 tex). The yarn is drawn in accordance with
die “00” is passed directly to the second heated draw roll the process described with reference to filament bundle
and thence around an associated separator roll. Filannent 0 1 of FIGURE 3. The yarn is passed from a feed roll
bundle “0” is wrapped a total of ten times around the two around a heated block 2; (5 wraps) maintained at 99
heated draw rolls and filament bundle "00" is wrapped a C., passed once around a 0.25 inch draw pin, and then
total of six times around the second heated draw roll and to draw roll 7 which is operated at a peripheral speed
its associated separator roll, after which the two filament of 750 y.p.m., after which the yarn is wound up at the
bundles are passed to a guide where they are combined same speed. The draw ratio is 3.395. The drawn yarn
into a single composite yarn, passed through an inter has a denier of 70 (7.8 tex). A portion of the drawn
lacer, and wound up on a yarn package at 2750 y-p.m. yarn is then heat set on the package at 84 C. for 4
The draw ratio is 2.8. At the end of the experiment, hours in an air oven. The heat-set yarn, identified be
the filament bundles are collected separately to measure low as yarn “U,' has a tenacity of 4.2 g.p.d., an elonga
their individual properties. Filament bundle "00” is 20 tion of 29%, a boil-off shrinkage of 7.5%, a yield point
found to have a denier of 35 (3.9 tex), a tenacity of 2.7 of 1.4 g.p.d., and an initial modulus of 81 g.p.d. An
g.p.d., an elongation of 30%, a yield point of 1.4 g.p.d., other portion of the drawn yard is passed from a roll
an initial modulus of 67 g.p.d., and a boil-off shrinkage operating at a peripheral speed of 161 y.p.m. into an
of 13.2%. Filament bundle “0” is found to have a denier oven containing steam at 100° C. and at atmospheric
of 35 (3.9 tex), a tenacity of 3.1 g.p.d., an elongation of 25 pressure and is passed out of the oven and wound up
25%, a yield point of 1.2 gp.d., an initial modulus of 76 on a package operating at a peripheral Speed of 149
gip.d.,
of .35%.
a boil-off shrinkage of 3.0%, and a AS.05 value y.p.m. The oven is 12 inches long and the allowed
A 1 x 1 plain weave fabric containing 90 ends per inch shrinkage in the oven is 7%. The yarn is then heat set
in the warp (7Z twist) and 72 ends per inch in the filling on the package at 180° C. for 3 hours. The steam
30 treated yarn, identified below as yarn "V.” has a tenacity
(3Z twist) is then prepared from the composite yarn. of 4.8 g.p.d., an elongation of 26%, a boil-off shrinkage
When boiled off, dier, and ironed, the fabric has a soft, of 0.0%, a yield point of 1.2 g.p.d., an initial modulus
supple hand and exhibits a specific volume of 2.3 cc./g. of 81 g.p.d., and a ASoos of 0.4%.
and a weight of 1.84 oz. ?.sq. yd. The fabric has an at Yarns “U” and “V” above are combined to form a
tractive appearance with no evidence of buckling. composite yarn which is twisted 7 turns per inch (Z)
EXAMPLE 8 for the warp and 3 turns per inch (Z) for the filling of
a 1 x 1 plain weave fabric containing 66 ends per inch
Poly(p-hexahydroxylylene terephthalate), derived from in the warp and 56 in the filling. The fabric is then
dimethyl terephthalate and a mixture of 65% trans- and 40 boiled off, dried, and ironed. The resulting fabric is
35% cis-p-hexahydroxylylene glycol, is spun at 300°C. puckered and buckled and has a harsh, undesirable hand.
through a spinneret having 27 round holes, each 0.009 Its specific volume is 2.34 cc./g. and its weight is 3.2
oZ./sq. yd.
inch in diameter. The extruded filaments are taken lap
by a roll operaing at a peripheral speed of 600 y.p.m. EXAMPLE 10
The yarn is drawn over a 1.6' diameter pin maintained
at 90° C at a speed of 500 y.p.m. The draw ratio is 2.5 Polyethylene terephthalate having a relative viscosity
The yarn is then passed into a 12' long atmospheric of 30 and containing 2% TiO2 is spun at 300° C. through
steam oven at 100 y.p.m. and wound up at 87 y.p.m. a spinneret having 27 round orifices, each 0.009 inch in
The yarn has a denier of 35, a tenacity of 2.8 g.p.d., diameter. The yarn is wound up at a speed of 1,500
an elongation of 30, a yield point of 1.0 g.p.d., a boil-off 50 y.p.m. and is found to have a spun denier of 120 (13.3
shrinkage of 4%, an initial modulus of 40 g.p.d., and a tex). The yarn is drawn and relaxed in accordance with
AS
low.
of 3.0%. This yarn is identified as yarn “S” be a modification of the process described with reference
In another spinning run, the experiment is repeated ex to filament bundle it' of FiGURE 3. The yarin is passed
cept that the pin temperature is 105 C., the draw ratio 55
from a feed roll around heated block 21 (5% wraps),
is 2.6, and the steam relaxation step is omitted. The which is maintained at 100 C., and thence over a draw
yarn, identified as yarn “T” below, has a denier 35, a pin to draw roll 7", the draw ratio being 3.024. The
tenacity of 3.0 g.p.d., an elongation of 20%, a yield yarn is next passed over a hot plate maintained at 220
point of 1.5, a boil-off shrinkage of 12%, and an initial C. and then through a fluid twister comprising a cir
modulus of 50 g.p.d. cular yarn passageway with a jet of air at 90 p.s. i. Sup
Yarns “S” and “T” above are combined to form a 60 pied circumferentially to the passageway. The yarn is
composite yarn which is twisted 7 turns per inch (Z) Wound up at a speed 10% lower than that of the draw
for the warp and 3 turns per inch (Z) for the filling of rol. The drawn and relaxed yarn has a denier of 40
a 1 x 1 plain weave fabric containing 93 ends per inch (4.4 tex), a tenacity of 3.1 g.p.d., an elongation of
in the warp and 76 in the filling. After the fabric is 30.4%, a boil-off shrinkage of 4.6% (spontaneous crimp
boiled off, dried, and ironed, it has a soft, supple hand ing observed during boi-off), a yield point of 1.2 gp.d.,
and exhibits a specific volume of 2.5 cc./g. and a weight an initial modulus of 63 gp.d., and a ASoos value of
of 2.0 oz./sq. yd. The fabric has an attractive ap 3.2%. This yarn is designated as yarn “W.”
pearance with no evidence of blacking. Yarn “W' is combined through an interlacing jet with
A sample of the fabric, in which the components have yarn “B” of Example 1 to form a composite yarn. A
0. 1 x 1 plain Weave fabric containing 90 ends per inch in
a tenacity ratio of 1.07, is dyed with 1 (p-ethylolanilino)- the warp (7Z twist) and 84 ends per inch in the filling
4,5-dihydroxy-8-nitroanthraquinone at the boil using (3Z twist) is then prepared from the yarn. Prior to
o-phenylphenol as a carrier. The resuiting dyed fabric boil-off, the fabric has the smooth, slick hand charac
is quite uniform in appearance, giving no evidence of teristic of continuous filament synthetic fabrics. How
heather or moiré effect. 75
ever, when the fabric is immersed in water at 100° C.
 8, 199,281
19 2)
for 5 minutes, dried, and ironed, the yarn comprising and wound up at a speed of 1000 y.p.m. to form yarn
the fabric becomes quite bulky and the hand of the fabric having a spun denier of 326 (36.2 tex). The yarn is then
becomes warm and soft. passed from a feed roll to a draw pin (2 wraps) 1.6 inches
When a sample of the fabric is dyed with 1 (p-ethyl in diameter maintained at a temperature of 135° C. and
olanilino)4,5-dihydroxy-8-nitroanthraquinone in the pres 5 thence over a hot plate maintained at 160° C. to a draw
ence of o-phenylphenol, a uniformly dyed fabric is pro roil operating at 149 y.p.m. The draw ratio is 3.1. The
duced which shows no evidence of heather. It is noted drawn yarn has a denier of 105 (11.7 tex), a tenacity
that the ratio of the tenacity of the high shrinkage com of 3 g.p.d., and an elongation of 23%. A Supply of
ponent to that of the low shrinkage component is 1.10. the drawn yarn is passed from a feed roll at 1000 y.p.m.
O through a jet tube wherein it is contacted with steam at
EXAMPLE 1. 285 C. and 50 p.s. i. As the yarn emerges from the
jet, it is impinged on a moving Screen, passed between
Polyethylene terephthalate/5-(sodium sulfo)-isophthal take-up rollis, and wound up at 875 y.p.m. This yarn,
ate (98/2) containing 0.3% TiO2 and having a relative designated as yarn “BB,' is crimped and has a denier
viscosity of 19 is spun at 295 C. through a spinneret 5 of 120 (13.3 tex), a tenacity of 2.7 g.p.d., an elongation
having 50 Y-shaped orifices formed by the intersection of 45%, an initial modulus of 15 g.p.d., a yield point of
of 3 slots, each 0.007 inch in length and 0.004 inch in 1.0 g.p.d., a boil-off shrinkage of 1.0% and a ASoos value
width. The yarn is wound up at a speed of 1,200 y.p.m. of 4.5%.
The spun yarn is then passed from a feed roll operating Yarn 'AA' is then combined with yarn “BB” through
at a peripheral speed of 168 y.p.m. to a draw pin (2 20 an interlacing jet to form a composite yarn. A X 1
Wraps) 1.6 inches in diameter maintained at a tempera plain weave fabric prepared from the composite yarn,
ture of 96° C. and thence to a draw roll operated at when immersed in 100° C. water for 5 minutes, dried,
454 y.p.m., finally being wound up. The draw ratio is and ironed, becomes quite bulky and the hand of the fab
2.7 and the denier of the drawn yarn is 70 (7.8 tex). ric becomes warm and Soft.
A supply of the drawn yarn is passed from a feed roll A sample of the fabric is dyed with 1 (p-ethyloianilino)
at 1,000 y.p.m. through a jet tube wherein it is con 4,5-dihydroxy-8-nitroanthraquinone in the presence of o
tacted with steam at 316 C. and 50 p.si. As the yarn phenylphenol at the boil. The resulting dyed fabric
energes from the jet, it is impinged on a moving screen, shows no evidence of heather, being quite uniform in
passed between take-up rolls, and wound up at 530 appearance. ..
y.p.in. This yarn, designated as yarn “X,” is crimped 30 Similar results are obtained by repeating the above
and has a denier of 125 (13.9 tex), a tenacity of 1.2 experiment, Substituting polyethylene 2,7-naphthalate for
g.p.d., an elongation of 86%, an initial modulus of 3.1 polyethylene 2,6-naphthalate.
g.p.d., a yield point of 0.5 g.p.d., a boil-off shrinkage of
0.4%, and a ASoos value of 18.7%. EXAMPLE 14
Yarn “X” is then combined with three strands of yarn 35 Polyethylene terephthalate/hexahydroterephth late (90/
'' of Example 3 through an interlacing jet to form a
composite yarn. A 1 x 1 plain weave fabric prepared 10) having a relative viscosity of 21.3 is spun at 295
from the composite yarn, when immersed in 100° C. C. through a spinneret having 34 round orifices, each
Water for 5 minutes, dried, and ironed, becomes quite 0.009 inch in diameter. The yarn is wound up at a speed
bulky and the hand of the fabric becomes warm and soft. 40 of 1200 y.p.m. and is found to have a spun denier of 254
(28.2 tex). The spun yarn is passed from a feed roll
EXAMPLE 12 around a heated block (5/2 . wraps), which is maintained
at 110 C., and thence to a draw roll which is operated
A commercially available 34-filament yarn comprises at a peripheral speed of 454 y.p.m. The draw ratio is 3.9.
polyethylene terephthalate having a relative viscosity of The yarn, designated as yarn. “CC,' has a denier of 65.
29 and containing 0.3% TiO2 which has been spun, drawn, (7.2 tex), a tenacity of 4.0 g.p.d., an elongation of 23%,
and then false twisted and heat set as described in U.S. a boil-off shrinkage of 10.1%, a yield point of 2.3 gip.d.,
Patent 2,803,109 to N.J. Stoddard et al. The yarn has and an initial modiulus of 93.g.p.d.
a denier of 70 (7.8 tex), a tenacity of 4.3.g.p.d., and elot A quantity of yarn “CC' is passed from a roll into an
gation of 24.9%, a boil-off shrinkage of 6.4% (spon 50 oven containing steam at 100° C. and at atmospheric
taneous crimping observed during boil-off), a yield point pressure and is then passed out of the oven and wound
of 1.2 g.p.d., an initial modulus of 49.7 g.p.d., and a up on a package. The oven is 12 inches long and the
ASoos value of 4.8%. When this yarn is combined with allowed shrinkage in the oven is 12%. The resulting
yarn “B” of Example 1 through an interacing jet to form yarn, designated as yarn “DD, has a boil-off shrinkage
a composite yarn and a 1 x 1 plain weave fabric is pre of 4.9% and a ASoos value of 3.8%.
pared, immersion of the fabric in water at 100° C. for Yarn "CC" is then combined with yarn “DD” through
5 minutes followed by drying and ironing produces a an interlacing jet to form a composite yarn. A 1 x 1.
bulky fabric with a warm, soft hand. plain. Weave fabric prepared from the composite yarn,
EXAMPLE. 13
when immersed in 100° C. water for 5 minutes, dried,
60 and ironed, becomes quite bulky and the hand of the
Polyethylene 2,6-naphthalate having a relative viscosity fabric becomes warm and soft.
of 30 is spun at 316 S. through a spinneret having 34 EXAMPLE 15
round orifices, each 0.009 inch in diameter. The yarn is
wound up at a speed of 1000 y.p.m. and is found to have A series of composite yarns are prepared from poly
a spun denier of 275 (30.6 tex). The spun yarn is then 65 ethylene terephthalate to illustrate the relationship be
passed from a feed roll to draw pin (2 wraps) 1.6 inches . tween tenacity ratio and dyeability. Each composite yarn.
in diameter maintained at a temperature of 154 C. and is composed of two components having a differential
thence to a draw roll operated at 149 y.p.m., finally being shrinkage of at least 2%, and with different tenacity
wound up. The draw ratio is 2.5. The yarn, identified values as shown in the table. Each yarn is woven into
as yarn “AA,” has a denier of 110 (12.2 tex), a tenacity a plain weave fabric, boiled off, and dyed with 1 (p-ethylol
of 2.4 g.p.d., an elongation of 12%, a yield point of anilino)4,5-dihydroxy-8-nitroanthraquinone at the boil
1.8 g.p.d., a boil-off shrinkage of 14%, and an initial using o-phenylphenol as a carrier. After a medium shade
modulus of 100 g.p.d. of blue is obtained, the dyed fabrics are rinsed, dried, and
In a separate spinning run, polyethylene 2,6-naphtha pressed, and examined for moiré. The results are given
late having a relative viscosity of 30 is spun at 316 C. 75 in the last column of the table where it is clearly shown
 3,199,281.
21 22
that uniform dyeability is achieved when the tenacity ratio from a glycol containing 2 to 12 carbon atoms and a di
falls in the range 0.7 to 1.1. carboxylic acid selected from the group consisting of tere
Tenacity
phthalic acid and the naphthalic acids.
Code Fabric Dye 4. The yarn of claim 3 wherein the polyester is poly
Tenacity ability 5 ethylene terephthalate.
High Shrink- Low Shrink- Ratio 5. The yarn of claim 3 wherein the polyester is poly
age Compo- age Compo
nent inent ethylene 2,6-naphthalate.
6. The yarn of claim 3 wherein the polyester is poly
1, 9 3.8 0.50 Moire. ethylene 2,7-naphthalate.
2.7 3.8 0.71 Unifornia, 0 7. The yarn of claim 3 wherein 0.5 to 3.5 mol percent
3.6 3.8 0.95 Do.
4.4 4. 1.07 Do. of the recurring structural units are derived from sodium
4.
4.4
3.5
2.2
1, 14 Slight Moire.
2.00 Moire. 3,5-dicarbomethoxybenzenesulfonate.
4. i. 5 3.12 Intense Moire. 8. The yarn of claim in which the ratio of the tenac
ities of the said two species is between 0.70 and 1.10.
It will be apparent that many widely different embodi 5
ments of this invention may be made without departing References Cited by fine Examiner
from the spirit and scope thereof, and therefore it is not UNITED STATES PATENTS
intended to be limited except as indicated in the ap 2,750,653 6/56 White ------------------ 28-81.
pended claims.
We claim: 20 2,764,468 9/56 Hare ------------------ 18-54
5. A composite linear condensation polyester yarn 2,789.340 4/57 Cresswell --------------- 28-72
comprising continuous filaments of at least two species, 2,880,056 3/59 Carr et al. -------------- 18-54
one of which is characterized by a zero load residual 2,979,883 4/61 Waltz ----------------- 28-72
shrinkage in the range of from 0.0% to about 20%, and 2,980,492 4/61, Jamieson et al. ---------- 28-72
a residual shrinkage at 0.05 gram per denier load of at 25 2,985,940 5/61 Weldon ---------------- 28-72
least about 1.2% less than the zero load residual shrink 3,007,227 11/61 Moler ----------------- 28-81.
age, and the other said species being characterized by a 3,015,148 1/62 Haddad ---------------- 28-72
zero load residual shrinkage at least 2% higher than the 3,038,240 6/62 Kovarik ---------------- 28-72
zero load residual shrinkage of the first said species. 3,039,171 6/62 Hume et al. ------------ 28-72
2. A fabric comprising the yarn of claim 1. 30 3,061,998 11/62 Bloch ----------------- 28-72
3. The yarn of claim wherein at least about 75% of MERVIN STEIN, Primary Examiner.
the recurring structural units of the polyester are derived DONALD W. PARKER, Examiner.