Note: Descriptions are shown in the official language in which they were submitted.
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POLYESTER YARN CUSHIONED RUGS AND METHODS OF MANUFACTURING
SAME
CROSS REFERENCE TO RELATED APPLICATIONS
111 The
application claims the benefit of U.S. Provisional Application No.
62/760,667, filed November 13, 2018, and of European Application No.
18208540.7, filed
November 27, 2018, the entire contents of each of which are incorporated
herein by
reference.
FIELD
[2] The
invention relates to washable rugs comprising polyester yarn, particularly
polyethylene terephthalate (PET) yarn, having a sufficiently low degree of
crystallinity so
as to improve dye pickup and enable a rinsing or scouring process to remove
excess dye
molecules following the dyeing cycle. The invention further relates to methods
of
preparing such washable rugs.
BACKGROUND
131 In the
production of rugs and carpets, there are several known methods for
dyeing the rugs and carpets to a desired color. These methods include: 1)
solution dyeing,
in which the dye is included in the polymer for the fiber before the fibers
are spun; 2) yarn
dyeing, in which the yarn is dyed after being spun but prior to being tufted
into the primary
backing; 3) jet dyeing, in which the dye is sprayed onto the fiber tufts after
tufting and 4)
beck dyeing, in which the rugs and carpet are submerged in a vat comprising
dye and water.
One advantage of beck dyeing is that it is more economical to dye carpet in
smaller batches
of different colors than the other methods.
[4]
Polyethylene terephthalate (PET), a thermoplastic fiber polymer resin in the
polyester family, is a commonly-used polymer for carpets and rugs. PET carpets
and rugs
are dyed with disperse dyes, which are generally water-insoluble. The dye used
for PET
acts more like a stain that is adhered to the PET fiber. This dye also stains
most other
materials in the backings of carpet and rugs. In carpet manufacturing the
finished backing
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is applied after the dyeing process to avoid staining. For beck dyed rugs, the
backing is
applied before dyeing. Therefore the backing is exposed to staining from the
disperse dyes.
11511 In
order to produce washable rugs, such as might be used in a bathroom or
kitchen, a thickness of foam and/or adhesive is attached to the underside of a
section of a
tufted primary backing. The foam and/or adhesive may provide cushioning and
support. Unlike carpet, rugs of this type are preferably washable by the
consumer.
[6] Until
now, PET rugs have primarily been produced using solution dyeing or yarn
dyeing for the tufts. However, in order to satisfy consumer demand for variety
and decor,
there would be a competitive advantage for a rug manufacturer if the PET rugs
could be
dyed using beck dyeing (which is also referred to as piece-dyeing in this
context). Smaller
batches of rugs produced in multiple colors could be manufactured more
efficiently.
However, in light of the previously attached foam and/or adhesive backing (or
"backing"),
a person of skill in the art would not have thought it possible to use beck
dyeing for PET
rugs. The entire rug, including the tufted primary backing and the rug backing
would be
submerged and saturated in the dye vat. The amount of dye required to properly
dye the
PET fibers would be thought to have one or more several undesirable features,
such dyeing
or staining of the backing, the inability for a consumer to wash the rugs, and
crocking and
transfer of dye, in which some of the dye is rubbed off of the rug and onto
adjacent surfaces,
such as the floor. This would be thought to be especially problematic with
regards to
darker colors, which require the absorption of more dye; this often results in
more excess
dye remaining in the rug backing when the rug is in the possession of the
consumer, which
in turn increases the risk and severity of crocking and transfer of dye.
171 The
process for removing excess dye following beck-dyeing is called
"scouring," and typically involves submerging the dyed carpet or rug in
caustic chemicals.
This is not always completely effective, especially when an excess of dye is
used, due to
the low dyeability of PET fibers and/or to the need to prepare darker-colored
fibers.
[8]
Accordingly, a need exists for a PET washable rug with improved dyeability and
less crocking, as well as improved methods of making and scouring such
washable rugs.
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SUMMARY
1191
According to a first aspect of the invention, a rug is provided, said rug
comprising
a) a textile face fabric comprising a polyester yarn, said polyester yarn
comprising polyester fibers or filaments, said fibers or filaments having an
average percent crystallinity of less than about 30%, and said fibers or
filaments comprising a crystallinity-reducing modifier; and
b) a backing layer secured to the textile face fabric.
[10] According to a second aspect of the invention, a method of
manufacturing a
cushioned rug is provided, said method comprising:
providing a greige fabric comprising polyester yarn, said polyester yarn
comprising polyester fibers or filaments, said fibers or filaments having a
percent
crystallinity of less than about 30%, and said fibers or filaments comprising
a
crystallinity-reducing modifier;
securing a backing layer to the greige fabric, so as to form an intermediate
rug;
beck-dyeing the intermediate rug with disperse dye, so as to form a dyed
rug; and
scouring the dyed rug with a caustic liquid.
According to a third aspect of the invention, a cushioned rug is provided,
said
cushioned rug being prepared by any of the above methods.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[11] Reference will now be made to the accompanying drawings, which are not
necessarily drawn to scale, and wherein:
[12] Figure 1 is a cross-sectional schematic view of a cushioned rug
according to one
embodiment of the present invention.
[13] Figure 2 is a cross-section diagram of a tufted carpet face fabric in
accordance
with a portion of an embodiment of the present invention.
[14] Figure 3 is a perspective view of an MRS extruder that is suitable for
use in a
process for manufacturing bulked continuous filament.
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DETAILED DESCRIPTION
[15] The present invention now will be described more fully hereinafter
with
reference to the accompanying drawings, in which some, but not all embodiments
of the
inventions are shown. Indeed, these inventions may be embodied in many
different forms
and should not be construed as limited to the embodiments set forth herein;
rather, these
embodiments are provided so that this disclosure will satisfy applicable legal
requirements.
Like numbers refer to like elements throughout. In the following description,
various
components may be identified as having specific values or parameters, however,
these
items are provided as exemplary embodiments. Indeed, the exemplary embodiments
do
not limit the various aspects and concepts of the present invention as many
comparable
parameters, sizes, ranges, and/or values may be implemented. The terms
"first," "second,"
and the like, "primary," "exemplary," "secondary," and the like, do not denote
any order,
quantity, or importance, but rather are used to distinguish one element from
another.
Further, the terms "a," "an," and "the" do not denote a limitation of
quantity, but rather
denote the presence of "at least one" of the referenced item.
[16] Each embodiment disclosed herein is contemplated as being applicable
to each
of the other disclosed embodiments. All combinations and sub-combinations of
the various
elements described herein are within the scope of the invention. Further, the
invention
illustratively disclosed herein suitably may be practiced in the absence of
any element
which is not specifically disclosed herein.
[17] It is understood that where a parameter range is provided, all
integers and ranges
within that range, and tenths and hundredths thereof, are also provided by the
embodiments. For example, "5-10%" includes 5%, 6%, 7%, 8%, 9%, and 10%; 5.0%,
5.1%, 5.2%....9.8%, 9.9%, and 10.0%; and 5.00%, 5.01%, 5.02%....9.98%, 9.99%,
and
10.00%, as well as, for example, 6-8%, 7-9%, 5.1%-9.9%, and 5.01%-9.99%.
[18] As used herein, "about" in the context of a numerical value or range
means
10% of the numerical value or range recited or claimed.
[19] As used herein, "recycled" refers to any material that is post-
consumer or post-
industrial material.
[20] As used herein, a "backing" refers to a foam and/or adhesive layer.
This is
distinct from the primary or secondary backings found in carpet.
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[21] As used here, "face fabric," or "carpet," refers to yarns or fibers in
combination
with a primary backing, and optionally a secondary backing.
[22] As used herein, "percent crystallinity" (Xc) of a polyester material
means the
portion of the material that is crystalline, compared to the entirety of the
material (which
may contain both crystalline and amorphous portions). The percent
crystallinity may be
assessed using differential scanning calorimetry, commonly referred to as DSC
and
calculated using the formula:
Xc = (AHf/ AH0) *100
where: AHf = enthalpy of melting of test sample in joules per gram (J/g) and
AH0 = the
enthalpy of melting for a fully crystalline polymer. The heating rate of the
DSC method
may be from 0.1-30 C/min, or from 1-10 C/min, in some embodiments. In a
preferred
embodiment, the heating rate is 10 C/min.
[23] As used herein, a "crystallinity-reducing modifier" is a modifier
which reduces
the crystallinity of a fiber or filament, compared to the crystallinity of a
fiber or filament
lacking the modifier, when added to the polymer from which the fiber or
filament is made.
In an embodiment, the crystallinity-reducing modifier reduces the
crystallinity by about 1-
90%. In an embodiment, the crystallinity-reducing modifier reduces the
crystallinity by
greater than about 1-90%.
[24] As used herein, a "greige" fabric is a fabric that is unfinished in
some way, such
as not being dyed.
[25] As used herein, to "secure" two objects together means to fix or
attach the
objects to each other, by means such as an adhesive or otherwise.
[26] As used herein, "synergistic," in terms of an effect, refers to the
case where the
interaction or presence of two elements produces a greater effect than would
be expected
based on the effect created by each of those elements individually. In the
present case, the
term may refer to a case where a fiber, Fl, comprising a modifier and having
decreased
crystallinity compared to another fiber, F2, which lacks said modifier and has
higher
crystallinity, exhibits a greater improvement in dyeability, or some other
property or metric
of performance, compared to F2, than would be expected based on the
improvements
exhibited by two other fibers, the first of which contains the modifier but
has the same
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degree of crystallinity as F2, and the second of which lacks the modifier but
has the same
degree of crystallinity as Fl.
[27] Non-limiting examples of classes of disperse dyes include azobenzene
derivatives and anthraquinone derivatives. Certain disperse dyes may comprise
nitro,
amine, or hydroxyl groups.
[28] According to a first aspect of the invention, a rug is provided, said
rug
comprising
b) a textile face fabric comprising a polyester yarn, said polyester yarn
comprising polyester fibers or filaments, said fibers or filaments having an
average percent crystallinity of less than about 30%, and said fibers or
filaments comprising a crystallinity-reducing modifier; and
b) a backing layer secured to the textile face fabric.
[29] According to some embodiments, said rug consists essentially of said
textile face
fabric and said backing layer. According to some embodiments, said rug
consists of said
textile face fabric and said backing layer.
[30] According to some embodiments, the average percent crystallinity is
less than
about 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%,
15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2% or 1%.
[31] According to some embodiments, said polyester fibers or filaments
comprise
polyethylene terephthalate (PET).
[32] According to some embodiments, said backing layer comprises foam, said
foam
having a density ranging from about 2 oz per square yard to about 50 oz per
square yard.
In a further embodiment, said backing layer comprises a polyurethane foam. In
an
embodiment, said backing layer comprises a viscoelastic foam material. In an
embodiment,
said backing layer comprises adhesive. In a further embodiment, said adhesive
is a foamed
adhesive. In an embodiment, said adhesive is not a foamed adhesive. In an
embodiment,
said rug does not comprise adhesive.
[33] According to some embodiments, the polyester fiber or filament
comprises the
modifier in an amount from about 0.5% to about 16% by weight. According to
some
embodiments, the polyester fiber or filament comprises the modifier in an
amount of less
than, greater than, or equal to about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%,
11%,
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12%, 13%, 14%, 15%, or 16% by weight. According to some embodiments, the
polyester
fiber or filament comprises the modifier in an amount from about 1% to about
15%, about
3% to about 14%, about 5% to about 12%, or about 8% to about 10% by weight.
Preferably,
the polyester fiber or filament comprises the modifier in an amount from about
8% to about
10%. According to some embodiments, the modifier is a branched polyester.
According to
some embodiments, the modifier is polybutylene adipate terephthalate (PBAT).
[34] According to some embodiments, the polyester yarn comprises continuous
filaments. According to some further embodiments, the continuous filaments are
bulked
continuous filaments.
[35] According to some embodiments, the polyester yarn exhibits increased
dyeability compared to a polyester yarn comprising polyester fibers or
filaments that have
the same degree of crystallinity, but lack the modifier. According to some
further
embodiments, the increase in dyeability is at least about 1% to at least about
300%.
According to some further embodiments, the increase is at least 1% to at least
25%.
[36] According to some embodiments, the polyester fibers or filaments
comprise
recycled polyester. In an embodiment, the recycled polyester is recycled PET.
According
to some embodiments, the recycled PET has been recovered from carpet waste or
plastic
bottles. According to some embodiments, the polyester fibers or filaments
comprise
recycled PET and virgin PET, and wherein the ratio of recycled PET to virgin
PET is from
about 99:1 to about 1:99.
[37] According to some embodiments, the rug is beck-dyed. According to some
embodiments, the textile face fabric and the backing layer have been dyed
simultaneously.
[38] According to some embodiments, the rug further comprises at least one
component selected from the group consisting of finishing agents,
delusterants, viscosity
modifiers, optical brighteners, matting agents, thermal stabilizing agents,
anti-oxidative
agents, anti-static agents, pigments, and ultra-violet stabilizing agents.
[39] According to a second aspect of the invention, a method of
manufacturing a
cushioned rug is provided, said method comprising:
providing a greige fabric comprising polyester yarn, said polyester yarn
comprising polyester fibers or filaments, said fibers or filaments having a
percent
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crystallinity of less than about 30%, and said fibers or filaments comprising
a
crystallinity-reducing modifier;
securing a backing layer to the greige fabric, so as to form an intermediate
rug;
beck-dyeing the intermediate rug with disperse dye, so as to form a dyed
rug; and
scouring the dyed rug with a caustic liquid.
[40] According to some embodiments, the average percent crystallinity is
less than
about 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%,
15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2% or 1%.
[41] According to some embodiments, the griege fabric is obtained by
tufting.
According to some embodiments, the yarn is obtained by melt spinning or by
extrusion
spinning.
[42] According to some embodiments, said caustic liquid comprises a
dispersant.
According to some further embodiments, said dispersant is naphthalene
sulfonate.
[43] According to some embodiments, said polyester fibers or filaments are
fibers or
filaments comprising polyethylene terephthalate (PET) yarn.
[44] According to some embodiments, said backing layer comprises foam, said
foam
having a density ranging from about 2 oz per square yard to about 50 oz per
square yard.
According to some further embodiments, said backing layer comprises a
polyurethane
foam. According to some embodiments, said backing layer comprises a
viscoelastic foam
material. According to some embodiments, said backing layer comprises
adhesive.
According to some further embodiments, said adhesive is a foamed adhesive.
According
to some embodiments, said adhesive is not a foamed adhesive.
[45] According to some embodiments, the polyester fiber or filament
comprises the
modifier in an amount from about 0.5% to about 16% by weight. According to
some
embodiments, the polyester fiber or filament comprises the modifier in an
amount of less
than, greater than, or equal to about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%,
11%,
12%, 13%, 14%, 15%, or 16% by weight. According to some embodiments, the
polyester
fiber or filament comprises the modifier in an amount from about 1% to about
15%, about
3% to about 14%, about 5% to about 12%, or about 8% to about 10% by weight.
Preferably,
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the polyester fiber or filament comprises the modifier in an amount from about
8% to about
10%. According to some embodiments, the modifier is a branched polyester.
According to
some embodiments, the modifier is polybutylene adipate terephthalate (PBAT).
[46] According to some embodiments, the polyester yarn comprises continuous
filaments. According to some further embodiments, the continuous filaments are
bulked
continuous filaments.
[47] According to some embodiments, the method further comprises the step
of
providing said polyester yarn, wherein said polyester fibers or filaments are
extruded fibers
or filaments obtained by melt extrusion of a molten polymer, said polymer
comprising said
crystallinity-reducing modifier, and drawing said extruded filaments so as to
obtain a
crystallinity of less than 30%.
[48] According to some embodiments, the polyester yarn exhibits increased
dyeability compared to a polyester yarn comprising polyester fibers or
filaments that have
the same degree of crystallinity, but lack the modifier. According to some
further
embodiments, the increase in dyeability is at least about 1% to at least about
300%.
According to some further embodiments, the increase is at least 1% to at least
25%.
[49] According to some embodiments, the polyester fibers or filaments
comprise
recycled polyester. According to some embodiments, the recycled polyester is
recycled
PET. In an embodiment, the recycled PET has been recovered from carpet waste
or plastic
bottles. According to some embodiments, the polyester fibers or filaments
comprise
recycled PET and virgin PET, and wherein the ratio of recycled PET to virgin
PET is from
about 99:1 to about 1:99.
[50] According to a third aspect of the invention, a cushioned rug is
provided, said
cushioned rug being prepared by any of the above methods.
[51] Fig. 1 shows a schematic cross-sectional view of a cushioned rug 2
according to
one embodiment of the present invention. As shown in Fig. 1, the cushioned rug
2 is a
layered structure comprising a top layer of face fabric 4, and a backing layer
6.
[52] In the illustrated embodiment of Fig. 1, the backing layer 6 comprises
a single
layer of foam. However, in other embodiments, the backing layer 6 may be a
composite of
multiple foam layers with an optional fabric layer on the bottom. For example,
backings of
various densities and/or thicknesses may be secured together to produce
various cushioning
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effects. These foams may also be embossed to create a pattern in the backing.
In particular
embodiments, the density of the foam may be 2 oz per square yard to 50 oz per
square yard.
In particular embodiments, the foam may have a thickness of up to 1". In an
embodiment,
the foam is in the form of a non-skid layer. In particular embodiments, the
foam is
viscoelastic foam or polyurethane foam. The foam can also be produced out of
natural and
synthetic latex rubber.
[53] The backing layer 6 may be a foamed adhesive, which is secured to the
face
fabric 4 by its own adhesive properties. In an alternate embodiment, the foam
may be a
layer of foam material which has been laminated to the face fabric 4.
[54] In an embodiment, the cushioned rug has an area from about 0.2-10 m2.
In an
embodiment, the cushioned rug has an area from about 0.3-2 m2.
[55] Fig. 2 illustrates schematically one potential carpet construction of
the face
fabric 4, or carpet, portion of Fig. 1. It is generally designated by
reference numeral 21.
The carpet 21 includes face yarn 22, which is tufted into a mesh, woven, or
spunbonded
fabric known as a primary backing 25. The primary backing 25 has pile yarns 22
tufted
therethrough extending outwardly from one face, a primary backcoating or
precoat 23 on
the opposite face, and at least one secondary backcoating or main coat
(frequently called a
skip coat) 24. Other layers may also be associated with the carpet 1.
[56] The primary backcoating or precoat 23 generally comprises carboxylated
latex
(e.g., a styrene-butadiene-based latex), PVC (polyvinylchloride), EVA
(ethylene-vinyl
acetate), or other polymer-based material, and the secondary backcoating 24
may also
include these same polymers. This primary and/or secondary backcoating may be
foamed
polymer. In an embodiment, the primary and/or secondary backcoating is a foam
which is
not an adhesive. One or both of the primary backcoatings 23 and secondary
backcoating(s)
24 can include a filler material. The most common filler is a mineral filler,
such as calcium
carbonate, although other fillers, such as alumina trihydrate, bauxite,
magnesium
hydroxide, or the like, may be utilized. In certain situations, calcium
carbonate can be used
with other common materials such as metal salts. The carpet 1 may be produced
with the
filler in one or both of the primary backcoating 23 and secondary
backcoating(s) 24
comprising waste carpeting as all or part of the filler. As an alternative,
only one single
backcoating may be provided instead of a primary and secondary backcoating.
Like the
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primary backcoating in the first alternative, this single backcoating will
also anchor the pile
yarns in the primary backing . This single backcoating may be composed of the
same
material as set out for the primary and secondary bckcoating.
[57] In making the carpet 1, generally, the fiber tufts are tufted through
a woven or
non-woven fabric, which is the primary backing 25. The part of the tufts on
the exposed
surface of the carpet comprises the face fiber or face yarn 2. A back-coating
23 is applied
to the back of the tufted structure to lock in the tufts. Next, a woven or non-
woven
secondary backing 24 is laminated to the back of the primary backing 25 to
give the carpet
added dimensional stability.
[58] The primary backing is a supportive scrim through which the tufts are
tufted,
and frequently is polyolefin, such as polyethylene or polypropylene; however,
other
materials such as polyester (including, for example, PET) can be used. For
example, slit
tapes made from PET may be used. The secondary backing is a fabric that is
adhered behind
the primary backing, sandwiching therein the back of the tufts with the
adhesive material.
The secondary backing is frequently made of polypropylene; however other
backing types,
such as jute, PVC (polyvinyl chloride), polyurethane, and PET, can be used.
The secondary
backing may be a non-woven fabric, including, but not limited to, spun-bond,
wet-laid,
melt-blown, and air-entangled.
[59] A filler material, such as calcium carbonate, and an adhesive material
are
generally applied to the backside of the tufted carpet backing as a slurry in
various
concentrations. There is almost always more filler than adhesive material. For
example, a
representative filler-to-adhesive ratio can comprise about 80 percent by
weight ("wt %" or
"%") calcium carbonate to about 20 wt % adhesive. While calcium carbonate is
one of the
most commonly employed filler materials, it should be recognized by those
skilled in the
art to which this disclosure pertains that carpets containing other filler
materials can be
used in the processes described herein.
[60] The adhesive material functions to bind the tufts with the backing.
The adhesive
material can include a latex, such as a carboxylic-styrene-butadiene rubber,
styrene-
butadiene rubber (SBR), natural rubber latex, vinyl acetate ethylene
copolymers (VAE or
EVA), other natural or synthetic rubbers, urethanes or polymers such as PET.
While latex
is one of the most commonly employed adhesive materials for holding tufts to
the carpet
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backing, it should be recognized by those skilled in the art to which this
disclosure pertains
that carpets containing other adhesives can be used in the processes described
herein.
[61] A wide variety of different polyesters may be used in the yarn. For
example, the
polyester can comprise a PET polymer such as LASER+ PET (available from DAK
Americas), NAN YA PET (Nan Ya Plastics Corporation, America), other PET
polymers,
or combisecnations thereof. PET can be produced, for example, by a
transesterification
reaction of dimethyl terephthalate and ethylene glycol, or by esterifi cation
of terephthalic
acid and ethylene glycol. PET may be provided from both virgin and recycled
resins. In
an embodiment, the PET comprises recycled PET that is recovered from soda and
water
bottles. The PET may be in flake or pellet form in any of the embodiments
described
herein. Further, a single polyester or a blend of two or more polyesters may
be used. Unless
otherwise noted, the polyester used in any of the embodiments of the invention
may be
virgin, recycled, or a blend thereof.
[62] The fibers may be formed from the polymer by any method known in the
art to
produce fibers from a single polyester or from a blend. The polymer can be
extruded to
have any shape or dimension suitable to polymeric carpet fibers. Moreover, the
carpet
fibers can undergo any post-spinning processes generally recognized as useful
in the
preparation of polymeric carpet fibers. The fibers may be as-spun or heat-set.
By "fibers",
reference is made to items, recognized in the art as fibers, such as
continuous filaments,
monofilaments, staple fibers, and the like. The fibers can be round or have
other shapes,
such as octalobal, delta, sunburst (also known as sol), scalloped oval,
trilobal, tetra-channel
(also known as quatra-channel), scalloped ribbon, ribbon, starburst, and the
like. The fibers
may also be solid, hollow, or multi-hollow. The fibers can be used to make
yarns, and the
fibers or yarns can be used to prepare a number of materials, particularly
carpets, rugs,
mats, and the like.
[63] The fibers of the present invention may further comprise other
components, such
as, without limitation, finishing agents, delusterants, viscosity boosters,
optical brighteners,
matting agents (e.g., titanium oxide), thermal stabilizing agents (e.g.,
phosphorous
compounds), anti-oxidative agents (e.g., hindered phenol), anti-static agents,
pigments,
ultra-violet blocking agents, and combinations thereof. In an embodiment, the
fibers do
not comprise at least one component selected from the group consisting of
finishing agents,
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delusterants, viscosity boosters, optical brighteners, matting agents, thermal
stabilizing
agents, anti-oxidative agents, anti-static agents, pigments, and ultra-violet
blocking agents.
[64] The yarns may be prepared according to any method for preparing yarns
recognized in the art as being useful therefore. For example, the yarn of the
invention
could be partially oriented yarn, spun drawn yarn, textured yarn, friction
false-twisted yarn,
and bulk continuous filament ("BCF") yarn. Preferred steps in preparing BCF
yarn
includes spinning (e.g., extruding, cooling, and coating filaments), single
stage or multi-
stage drawing (such as with heated rolls, heated pin or hot fluid assist) at a
defined
temperature and draw ratio, annealing, bulking, entangling, optionally
relaxing, and
winding the filaments on a package for subsequent use.
DISCUSSION AND EXAMPLES
[65] One improvement for reducing the amount of time and energy required to
properly dye polyester fibers is a modifier that is mixed into the polymer of
the fiber before
the fiber is created, such as during an extrusion process. One such modifier
is polybutylene
adipate terephthalate (PBAT) (available from BASF SE, Ludwigshafen, Germany,
under
the ecoflex brand). One genus of suitable modifiers are branched polyester
modifiers.
[66] The PBAT modifier acts by adding amorphous zones to the structure of
the fiber.
Generally, a fiber with decreased crystallinity, and therefore with more
amorphous zones,
will exhibit greater dyeability than a fiber having a greater degree of
crystallinity, even if
the fiber is otherwise identical. The amorphous zones provide more locations
in the fiber
for the dye to be taken up. While these amorphous zones decrease crystallinity
and thus
fiber tenacity, this disadvantage is offset by the increased take up of the
dye by the fiber.
By using the modifier and increasing the take-up of the dye by the fiber (i.e.
increasing the
dyeability of the fiber), achieving the desired shade occurs more quickly and
less dye is
required in the vat, or less time and machine energy are required, to dye the
fiber. As a
result, the fiber (or a rug containing the fiber) can spend less time in the
beck-dyeing vat.
In a cushioned rug, this results in less dye being taken up by the backing,
and less dye that
must be removed from the backing prior to being provided to the consumer.
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[67] Advantageously, a scouring process for removing excess dye from a beck-
dyed
PET washable rug after dyeing has been completed. The scouring process
involves
submerging the dyed rugs in a vat of caustic chemicals, such as soda ash or
sodium
hydroxide, which act to remove excess dye from the fibers. This scouring
process can be
improved by adding dispersant chemicals, such as naphthalene sulfonate, to the
vat.
[68] The present inventors have found that by using a modifier in a PET
fiber that
allows for less dye to be used in the vat, or for faster dyeing, thereby
reducing the amount
of dye taking up by the backing, in combination with a scouring process using
both caustic
and dispersant chemicals to remove excess dye, it is possible to beck dye rugs
made with
PET fibers without the resultant rug having an undesirably stained backing or
causing
crocking or transfer of dye to the floor. In addition, the rugs are washable
by the consumer.
The inventors are the first to combine a pre-dyeing fiber modifier with a post-
dyeing
scouring process using both caustic and dispersant chemicals. By reducing the
amount of
dye required for the dyeing step, and then removing excess dye after the
dyeing step, the
inventors have invented a beck-dyed PET rug, and process for making the same,
that is
colorfast and washable. The following method describes the process of making a
cushioned
rug using PET yarn and a PBAT modifier; one of skill in the art will readily
recognize that
the method may be practiced with different polyesters and modifiers.
[69] One method for producing fibers of the current invention using
recycled
polyester bottles is via a Multiple Rotating Screw (MRS) extruder, as
described in U.S.
Patent No. 8,597,553, which is hereby incorporated by reference in its
entirety. This
process produces bulked continuous filament (BCF).
[70] A BCF (bulked continuous filament) manufacturing process, according to
the
particular embodiment, may generally be broken down into four steps: (1)
preparing flakes
of polyester polymer from post-consumer bottles for use in the process; (2)
passing the
flakes through an extruder that melts the flakes and purifies the resulting
polymer; (3)
feeding the polyester polymer into a spinning machine, and (4) adding a
modifier into the
spinning machine, where the spinning machine turns the polyester polymer (and
modifier
into filament or fiber for use in manufacturing yarns for carpets and rugs.
[71] As may be understood from Fig. 3, in particular embodiments, the MRS
extruder
includes a first single-screw extruder section 410 for feeding material into
an MRS
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section 420 and a second single-screw extruder section 440 for transporting
material away
from the MRS section.
[72] In particular embodiments, after the PET polymer has been extruded and
purified by the above-described extrusion process, the molten polymer is
cooled into pellets
These pellets are then melted and fed into a BCF (or "spinning") machine. PBAT
is also
added to the spinning machine, which is configured to turn the molten polymer
and PBAT
into bulked continuous filament. If using virgin polymer (such as virgin PET),
no
purification step would be performed, and pellets of the virgin polymer would
be added
directly to the spinning machine.
[73] In particular embodiments, the modifier is combined with the PET at a
loading
percentage from 1-16%. In a further embodiment, the modifier is combined with
the PET
at a loading percentage of 8%.
[74] The spinning machine extrudes molten polymer through small holes in a
spinneret in order to produce yarn filaments from the polymer. The molten
polymer cools
after leaving the spinneret. The yarn is then taken up by rollers and
ultimately turned into
filaments that are used to produce carpet and rugs. In various embodiments,
the yarn
produced by the spinning machine may have a tenacity between about 2 gram-
force per
unit denier (gf/den) and about 9 gf/den. In particular embodiments, the
resulting yarn has
a tenacity of at least about 2 gf/den. In particular embodiments, the spinning
is performed
at a temperature within the range of 220 C-350 C. In a further embodiment, the
spinning
is performed at 280 C.
[75] Step 5: Preparing Cushioned Rug
[76] The yarn is tufted to a primary backing to form a "face fabric." The
tufted carpet
is taken to a coater where liquid foam or adhesive material is pumped directly
onto the
back of the carpet. As the carpet moves under the applicator roller, the
backing material is
scraped or gauged to the desired thickness. The carpet may pass through a
preheat oven to
allow a pattern to be embossed into the backing material. The material is then
taken
through a heated oven or alternate energy source to cure the foam or adhesive
to form a
cushioned rug.
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[77] Step 6: Beck-dyeing
[78] The cushioned rug is then cut and sewn and put into a batch size
suitable to be
beck-dyed in a vat of disperse dye. The size of the batch is dependent on the
capacity of
the beck machine. The rugs are loaded into the beck and desired ambient water
level is
added. Water content is at a range of a 3/1 ratio up to a 20/1 ratio to the
weight of the rugs.
Disperse dye is then added to the beck. The beck water is then heated at a
controlled rate
up to 212F causing the dye to adhere to the fiber. The rugs are circulated in
the beck until
the dye is evenly distributed on the fiber. The dye water is drained and the
beck is refilled
with water for a rinse cycle. The rinse water is then drained. The rinse cycle
can be
repeated as necessary. If the rugs require scouring, the beck will fill with
water again to
begin the scouring cycle. If the rugs do not require scouring, the rugs will
move to the
drying process.
[79] Step 7: Scouring
[80] Following beck-dyeing, if necessary, the cushioned rug is scoured so
as to
remove excess dye. After the dyeing and rinsing process, the beck is filled
with water again.
Caustic liquid, such as a liquid comprising soda ash or sodium hydroxide is
added to the
beck. The caustic liquid may include a dispersant. In an embodiment, the
dispersant is
naphthalene sulfonate. In an embodiment, the caustic liquid is at a pH from
7.5-11. The
rugs are circulated in the beck in a water temperature ranging from ambient up
to 212 F.
The scouring water is then drained and the beck goes back into rinsing mode
before the
rugs are moved to the drying process.
[81] It is known that trace levels of dye may cause staining when the rug
is in use,
particularly in humid environments. Scouring with caustic liquid and a
dispersant may
allow removal of this excess residual trace level of dye to a further extent,
even completely,
which scouring step itself constitutes a separate, independent aspect of the
present
invention.
[82] In alternate embodiments, the caustic liquid is at a pH of about 7.5
8, 8.5, 9, 9.5,
10, 10.5, or 11. In alternate embodiments, the caustic liquid is at a pH of
greater than or
less than about 7.5, 8, 8.5, 9, 9.5, 10, 10.5, or 11.
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[83] Alternate embodiments
[84] Non-MRS Extrusion System
[85] In particular embodiments, the process may utilize a polymer flow
extrusion
system other than the MRS extruder described above. The alternative extrusion
system may
include for example, a twin screw extruder, a multiple screw extruder, a
planetary extruder,
or any other suitable extrusion system. The process may include a plurality of
any
combination of any suitable conical screw extruders (e.g., four twin screw
extruders, three
multiple screw extruders, etc.).
[86] Variations on mixing polyester polymer and modifier
[87] In some alternate embodiments, there is no step of cooling the
purified, melted
PET into pellets. In this alternate embodiment, the melted components can be
fed directly
into a suitable spinning machine to be combined with the modifier and turned
into fiber.
Recycled PET flake is fed into the extruder from one feeder and the modifier
is fed into
the extruder from another feeder.
[88] In an alternate embodiment, recycled PET pellets are fed into the
extruder from
one feeder and the modifier is fed into the extruder from another feeder.
[89] In an alternate embodiment, virgin PET pellets are fed into the
extruder from
one feeder and the modifier is fed into the extruder from another feeder.
[90] In an alternate embodiment, recycled PET pellets and modifier are
mixed
together in one feeder before melting, and the pellet mixture is fed into the
extruder.
[91] In an alternate embodiment, virgin PET pellets and modifier are mixed
together
in one feeder before melting and the pellet mixture is fed into the extruder.
[92] In an alternate embodiment, recycled PET pellets are mixed with virgin
PET
pellets and fed into the extruder from one feeder and the modifier is fed into
the extruder
from another feeder.
[93] In an alternate embodiment, recycled PET pellets, virgin PET pellets,
and the
modifier are mixed together in one feeder before melting and the pellet
mixture is fed into
the extruder.
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[94] In all of these variations, other additives may be used, such as
delusterants,
colorants, stabilizers, etc., as discussed previously.
CONCLUSION
[95] Many modifications and other embodiments of the inventions set forth
herein
will come to mind to one skilled in the art to which these inventions pertain
having the
benefit of the teachings presented in the foregoing descriptions. Therefore,
it is to be
understood that the inventions are not to be limited to the specific
embodiments disclosed
and that modifications and other embodiments are intended to be included
within the scope
of this disclosure. Although specific terms are employed herein, they are used
in a generic
and descriptive sense only and not for purposes of limitation.
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