FIELD
[0001] 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
[0002] 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.
[0003] 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 dispersed dyes. 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 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 dispersed dyes.
[0004] 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.
[0005] 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 décor,
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.
[0006] 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.
[0007] 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.
SUMMARY
[0008] according to the first aspect of the invention a rug is provided, 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.
[0009] According to some embodiments, the rug may coprise 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 a backing
layer secured to the textile face fabric.
[0010] According to some embodiments, the polyester fibers or filaments may comprise polyethylene
terephthalate (PET).
[0011] According to some embodiments, the backing layer may comprise foam, the foam having
a density ranging from about 2 oz per square yard to about 50 oz per square yard.
[0012] According to some embodiments, the backing layer may comprise a polyurethane foam.
[0013] According to some embodiments, the backing layer may comprise an adhesive.
[0014] According to some embodiments, the adhesive may be a foamed adhesive.
[0015] According to some embodiments, the polyester fiber or filament may comprise the modifier
in an amount from about 0.5% to about 16% by weight.
[0016] According to some embodiments, the modifier may be a branched polyester. The modifier
may be polybutylene adipate terephthalate (PBAT).
[0017] According to some embodiments, the polyester yarn may comprise continuous filaments.
The filaments may be bulked continuous filaments.
[0018] According to some embodiments, the polyester yarn may exhibit increased dyeability
compared to a polyester yarn comprising polyester fibers or filaments that have the
same degree of crystallinity, but lack the modifier. The increase in dyeability may
be at least about 1% to at least about 300%, e.g. at least 1% to at least 25%.
[0019] According to some embodiments, the polyester fibers or filaments may comprise recycled
polyester. The recycled polyester may be recycled PET. The recycled PET may have been
recovered from carpet waste or plastic bottles.
[0020] According to some embodiments, the polyester fibers or filaments may 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.
[0021] According to some embodiments, the rug may further comprise 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.
[0022] 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.
[0023] According to some embodiments, the caustic liquid may comprise a dispersant.
[0024] According to some embodiments, the dispersant may be naphthalene sulfonate.
[0025] According to some embodiments, the polyester fibers or filaments may be fibers or
filaments comprising polyethylene terephthalate (PET) yarn.
[0026] According to some embodiments, the backing layer may comprise foam, said foam having
a density ranging from about 2 oz per square yard to about 50 oz per square yard.
[0027] According to some embodiments, the backing layer may comprise a polyurethane foam.
[0028] According to some embodiments, the backing layer may comprise adhesive.The adhesive
may be a foamed adhesive.
[0029] According to some embodiments, the polyester fibers or filaments may comprise the
modifier in an amount from about 1% to about 16% by weight.
[0030] According to some embodiments, the modifier may be a branched polyester. The modifier
may be polybutylene adipate terephthalate (PBAT).
[0031] According to some embodiments, the polyester yarn may comprise continuous filaments.
The continuous filaments may be bulked continuous filaments.
[0032] According to some embodiments, the method further may comprise 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%.
[0033] According to some embodiments, the polyester yarn may exhibit increased dyeability
compared to a polyester yarn comprising polyester fibers or filaments that have the
same degree of crystallinity, but lack a modifier. The increase in dyeability may
be at least about 1% to at least about 300%, such as at least 1% to at least 25%.
[0034] According to some embodiments, the polyester fibers or filaments may comprise recycled
polyester. The recycled polyester may be recycled PET. The recycled PET has been recovered
from carpet waste or plastic bottles. The polyester fibers or filaments may comprise
recycled PET and virgin PET, and wherein the range of recycled PET to virgin PET ranges
from about 99:1 to about 1:99.
[0035] The methods according to this second aspect of the inventing may provide rugs according
to the first aspect of the invention.
[0036] According to a third aspect of the inventing, a method to provide a rug is provided,
the method comprises
providing 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.
[0037] Aspects of the first and/or second aspect of the invention may be applied to the
methods of the third aspect of the invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0038] Reference will now be made to the accompanying drawings, which are not necessarily
drawn to scale, and wherein:
Figure 1 is a cross-sectional schematic view of a cushioned rug according to one embodiment
of the present invention.
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.
Figure 3 is a perspective view of an MRS extruder that is suitable for use in a process
for manufacturing bulked continuous filament.
DETAILED DESCRIPTION
[0039] 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.
[0040] 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.
[0041] 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%.
[0042] As used herein, "about" in the context of a numerical value or range means ±10% of
the numerical value or range recited or claimed.
[0043] As used herein, "recycled" refers to any material that is post-consumer or post-industrial
material.
[0044] 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.
[0045] As used here, "face fabric," or "carpet," refers to yarns or fibers in combination
with a primary backing, and optionally a secondary backing.
[0046] 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 is
assessed using differential scanning calorimetry, commonly referred to as DSC and
is calculated using the formula:
where: ΔH
f = enthalpy of melting of test sample in J/g and ΔH
o = the enthalpy of melting for a fully crystalline polymer.
[0047] 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
[0048] As used herein, a "greige" fabric is a fabric that is unfinished in some way, such
as not being dyed.
[0049] 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.
[0050] 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, F1, 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 degree of crystallinity as F2, and the second of which lacks the
modifier but has the same degree of crystallinity as F1.
[0051] An embodiment of the invention is a 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.
[0052] In an embodiment, said rug consists essentially of said textile face fabric and said
backing layer. In an embodiment, said rug consists of said textile face fabric and
said backing layer.
[0053] In an embodiment, 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%.
[0054] In an embodiment, said polyester fibers or filaments comprise polyethylene terephthalate
(PET).
[0055] In an embodiment, 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.
[0056] In an embodiment, the polyester fiber or filament comprises the modifier in an amount
from about 0.5% to about 16% by weight. In 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.
In 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%.In an embodiment, the modifier is
a branched polyester. In an embodiment, the modifier is polybutylene adipate terephthalate
(PBAT).
[0057] In an embodiment, the polyester yarn comprises continuous filaments. In a further
embodiment, the continuous filaments are bulked continuous filaments.
[0058] In an embodiment, 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. In a further embodiment, the increase in
dyeability is at least about 1% to at least about 300%. In a further embodiment, the
increase is at least 1% to at least 25%.
[0059] In an embodiment, the polyester fibers or filaments comprise recycled polyester.
In an embodiment, the recycled polyester is recycled PET. In an embodiment, the recycled
PET has been recovered from carpet waste or plastic bottles. In an embodiment, 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.
[0060] In an embodiment, 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.
[0061] An embodiment of the invention is a method of manufacturing a cushioned rug, 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.
[0062] In an embodiment, 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%.
[0063] In an embodiment, the griege fabric is obtained by tufting. In an embodiment, the
yarn is obtained by melt spinning or by extrusion spinning.
[0064] In an embodiment, said caustic liquid comprises a dispersant. In a further embodiment,
said dispersant is naphthalene sulfonate.
[0065] In an embodiment, said polyester fibers or filaments are fibers or filaments comprising
polyethylene terephthalate (PET) yarn.
[0066] In an embodiment, 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.
[0067] In an embodiment, the polyester fiber or filament comprises the modifier in an amount
from about 0.5% to about 16% by weight. In 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.
In 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%. In an embodiment, the modifier is
a branched polyester. In an embodiment, the modifier is polybutylene adipate terephthalate
(PBAT).
[0068] In an embodiment, the polyester yarn comprises continuous filaments. In a further
embodiment, the continuous filaments are bulked continuous filaments.
[0069] In an embodiment, 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%.
[0070] In an embodiment, 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. In a further embodiment, the increase in
dyeability is at least about 1% to at least about 300%. In a further embodiment, the
increase is at least 1% to at least 25%.
[0071] In an embodiment, the polyester fibers or filaments comprise recycled polyester.
In an embodiment, the recycled polyester is recycled PET. In an embodiment, the recycled
PET has been recovered from carpet waste or plastic bottles. In an embodiment, 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.
[0072] 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.
[0073] 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 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.
[0074] 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.
[0075] 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.
[0076] The primary backcoating or precoat
23 generally comprises carboxylated latex (
e.g., a styrene-butadiene-based latex), PVC (polyvinylchloride), EVA (ethylenevinyl 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. 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 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.
[0077] 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.
[0078] 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.
[0079] 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.
[0080] 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
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.
[0081] 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 esterification 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.
[0082] 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.
[0083] 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.
[0084] 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
[0085] 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.
[0086] 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.
[0087] 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.
[0088] 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.
[0089] 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).
[0090] 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.
[0091] 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 section
420 and a second single-screw extruder section
440 for transporting material away from the MRS section.
[0092] 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.
[0093] 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%.
[0094] 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.
Step 5: Preparing Cushioned Rug
[0095] 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.
Step 6: Beck-dyeing
[0096] 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. 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.
Step 7: Scouring
[0097] 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.
[0098] 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.
[0099] 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.
Alternate embodiments
Non-MRS Extrusion System
[0100] 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.).
Variations on mixing polyester polymer and modifier
[0101] 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.
[0102] 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.
[0103] 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.
[0104] 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.
[0105] 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.
[0106] 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.
[0107] 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.
[0108] In all of these variations, other additives may be used, such as delusterants, colorants,
stabilizers, etc., as discussed previously.
CONCLUSION
[0109] 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.