Note: Descriptions are shown in the official language in which they were submitted.
CA 02191990 1997-06-02
1
METHOD FOR MAKING PIGMENTED SYNTHETIC FILAMENTS
FIELD OF INVENTION
The present invention relates generally to the field
of thermoplastic polymeric materials containing one or more
additives. In preferred exemplary embodiments, the present
invention relates to synthetic filament additives (e. g.,
colorants) and to methods for incorporating such additives in
melt flows of filament-forming thermoplastic polymeric
materials prior to melt-spinning to form synthetic filaments
therefrom.
BACKGROUND AND SUMMARY OF THE INVENTION
The incorporation of additives in so-called "neat"
thermoplastic polymeric host materials (that is, polymeric
materials containing no additives) so as to achieve desired
physical properties is well known. Thus, the art has
conventionally incorporated colorants, stabilizers,
delusterants, flame retardants, fillers, antimicrobial agents,
antistatic agents, optical brighteners, extenders, processing
aids and other functional additives into polymeric host
materials in an effort to "engineer" desired properties of the
resulting additive-containing polymeric host material. Such
additives are typically added any time prior to shaping of the
polymeric material, for example, by spinning or molding (e. g.,
extrusion, injection, or blow-molding) operations.
CA 02191990 1999-12-29
2
The incorporation of colorant additives in filaments formed by
melt-spinning a polymeric material has presented unique challenges. For
example, the amount of particulate pigment dispersed in a concentrate
which is added to the polymeric material must be sufficiently high to
s impart satisfactory color density, but must not be so high as to interrupt
the spinning process. One prior proposal for incorporating colorant
additives in thermoplastic polymeric materials is disclosed in U.S. Patent
No. 5,236,645 to Frank R. Jones on August 17, 1993-
According to the Jones '645 patent, additives are introduced into a
thermoplastic melt by feeding at least one additive in an aqueous vehicle
containing a dispersant to form an aqueous additive stream to a vented
extruder which is extruding a thermoplastic. The aqueous portion of the
15 aqueous additive stream is thereby volatilized within the extruder and is
removed therefrom via an extruder vent. As a result, a substantially
homogeneous system containing the thermoplastic, dispersant and the
additive is obtained which may thereafter be spun into a filament by
melt-extrusion through filament-forming orifices in a spinneret associated
2o with a spin pack assembly.
Although the techniques disclosed in the Jones '645 patent are
entirely satisfactory, some further improvements to incorporating additives
in a melt flow of thermoplastic polymeric materials would be desirable.
2s For example, it would especially be desirable if the additive stream was
non-aqueous as this would obviate the need for a vented extruder (i.e.,
CA 02191990 1999-12-29
3
since a volatilized aqueous portion of the additive stream
would not then need to escape prior to melt-spinning).
Furthermore, it is entirely possible that a non-aqueous
additive stream could be introduced physically near or into the
spin pack assembly where it can be mixed with a melt flow of
the polymeric material immediately upstream of the spinneret
orifices (and preferably downstream of the polymer filter
section of the spin pack assembly) thereby bypassing the
l0 extruder. Such a possibility would then allow additive
concentration and/or types to be changed on a continuous basis
to produce sequential lengths of melt-spun filaments having
desired, but different, properties and/or characteristics.
That is, the upstream processing equipment, for example, the
extruders and process piping, which supply the polymeric host
material to the spin pack assembly would not necessarily need
to be shut down for purposes of cleaning. Furthermore, by
introducing a non-aqueous additive stream directly into the
spin pack assembly, the flushing time would be relatively short
thereby allowing, for example, quick color changes to occur
20 from one filament production batch to another. It is towards
providing such improvements that the present invention is
directed.
The present invention as broadly disclosed
hereinafter is concerned with a nonaqueous additive concentrate
system for thermoplastic polymeric host materials which may be
added directly to a melt flow of the polymeric material in
metered amounts.
The invention as claimed is however "restricted" to
the use of such system. More precisely, it relates to a method
of making pigmented filaments comprising:
CA 02191990 1999-12-29
3a
(i) supplying a melt flow of a melt-spinnable
polymeric host material to spinneret orifices;
(ii) providing a dispersible additive which is
comprised of (1) a dispersant polymer, (2) solid
pigment particles coated by said dispersant polymer so
as to form solid dispersant-coated pigments having an
average particle size of greater than 5 Vim, and (3) a
liquid nonaqueous polymer carrier in which said solid
dispersant coated pigments are dispersed;
(iii)incorporating the dispersible additive within at
least a portion of the melt flow of polymeric host
material upstream of the spinneret orifices, to form a
mixture of the polymeric host material and the
dispersible additive, and allowing said dispersant-
coated particles to break apart into average particle
sizes of 1 ~m or less in the mixture, and then
(iv) extruding a melt of the mixture through the
spinneret orifices to form pigmented filaments.
CA 02191990 1999-12-29
4
This invention as claimed also relates to a
method of making additive-containing melt-spun filaments
comprising the steps of:
(a) providing an additive concentrate system which is
comprised of (1) a dispersant polymer, (2) solid
pigment particles coated by said dispersant
polymer so as to form solid dispersant-coated
pigments having an average particle size of
greater than 5 ~Cm, and (3) a liquid nonaqueous
polymer carrier in which said solid dispersant
coated pigments are dispersed;
(b) introducing the additive concentrate system into
at least a portion of a melt of a polymeric host
material to form a mixture of the polymeric host
material and the additive concentrate system and
allowing the dispersant-coated pigment particles
to break apart to average particle sizes of 1 ~,m
or less in the mixture; and thereafter
(c) melt-spinning the mixture to form additive-
containing melt-spun filaments.
The additive concentrate system according to the
present invention includes a filament additive which is
dispersed in a liquid or liquefied nonaqueous carrier. The
filament additive may, during use, be in the form of a solid
particulate or a liquid. When a solid particulate is used, the
additive system of this invention most preferably also includes
a dispersant which coats the particulate additive. The
additive concentrate system according to this invention is most
preferably in the form of a flowable paste which can be added
in metered amounts (dosed) to a melt flow of the polymeric
material prior to being spun into filaments, for example near
or into the spin pack assembly upstream of the assembly's
filament-forming spinneret orifices.
CA 02191990 1999-12-29
4a
In such a manner, therefore, synthetic filament
batches having different additives may be produced sequentially
on a continuous basis without costly equipment downtime. That
is, the same spin pack assembly may be used to produce a first
batch of filaments containing one type of additive during one
production interval, and then used to produce a second batch of
filaments containing a second type of additive during a
succeeding production interval by changing the additive which
is introduced into the filament-forming melt. Moreover, the
time interval needed to change between different additives is
to relatively short since the additive system is most preferably
introduced into the melt flow near or into the spin pack
assembly which in turn reduces significantly the time needed to
flush residual additive incorporated into the first batch of
filaments. Production of different additive-containing
filaments (e.g., filaments containing different colorants) is
now possible in a relatively short period of time without
stopping filament winding.
Thus, the invention also provides a method of
continuously producing sequential lengths of different
20 additive-containing
2~9~~~Q
filaments by continuously supplying a melt-spinnable polymeric host
material to orifices of a spinneret and, d~iring a first time interval,
controllably dosing a concentrate system having one additive into the
polymeric material to form a first polymeric mixture which is extruded
5 through the spinneret orifices. Subsequently, during a second time
interval, another concentrate system containing a different additive is
controllably dosed into the polymeric material without disrupting the
continuous supply of polymeric material to the spinneret orifices to form a
second polymeric mixturE which is extruded through the spinneret
~ o orifices.
During the change of additive concentrate, an intermediate time
interval will be needed in order to flush the spinneret of residual amounts
of the first additive concentrate. Thus, during the intermediate time
~s intervals, an intermediate length of filaments will be produced which will
change over the filament length from containing all of the first additive
concentrate to containing all of the second additive concentrate. This
intermediate length of filaments produced according to the present
invention will be handled separately from the first and second lengths of
2o production filaments. However, the amount of such intermediate length of
filaments will be relatively small since, as noted above, the time interval
needed to flush the spinneret of residual amounts of the first additive
concentrate is relatively short.
2s Other advantages ensue from introducing the additive concentrate
system to the polymeric host material within the spin pack assembly. For
CA 02191990 1997-06-02
6
example, the spin pack assembly and its associated spinneret
orifices may be so designed to form melt-spun multicomponent
filaments (e. g., filaments having multiple domains of different
polymer blends, colorants and/or other additives) such as those
filaments disclosed in U.S. Patent No. 5,162,074 to Hills by
splitting a melt-flow of polymeric host material into two or
more subflows within the spin pack assembly. According to the
present invention, therefore, the additive concentrate system
may be introduced into the spin pack assembly and mixed with
one or more of such subflows of polymeric host material without
being mixed with other subflows so as to form multicomponent
filaments. Therefore, while the discussion which follows
emphasizes the production of filaments in which the additive
concentrate system is substantially homogeneously mixed through
the filament cross-section, it will be understood that the
present invention is likewise applicable to the formation of
multicomponent filaments whereby the additive concentrate
system is substantially homogeneously mixed throughout one or
more multiple polymeric domains in the filament cross-section
without being present in the other domains) (e. g., as in core-
sheath filaments, pie wedge filaments, side-by-side filaments
and the like).
As noted above, significant processing flexibility
ensues according to the present invention. Processing
flexibility is the result of at least two features of the
present invention. First, additive concentrate systems can be
mixed above the spinneret with either the entire host polymer
or only a portion of the host polymer. For example, a
functional additive (e.g., an
~~9~~~Q
antistatic agent) concentrate system might be mixed with only a third of
the host polymer such that a third of the filaments spun contain the
antistatic agent and the remaining two-thirds do not.
Second, two or more additive concentrate systems can be mixed
with the host polymer above the spinneret to achieve a single attribute in
the fiber that is spun. For example, a yellow additive concentrate system
and a blue additive concentrate system can be concurrently mixed with
host polymer above the spinneret to provide a green fiber when the
mixture is spun. There is no theoretical limit for the number of additive
concentrate systems that can be mixed with the host polymer above the
spinneret. The number of additive concentrate systems is limited only by
the space available to inject the systems into the line. It is contemplated
that the host polymer might also contain some additive prior to mixing
~ s above the spinneret.
These two features of the present invention are not mutually
exclusive and great flexibility ensues from combining them. Using color
as an example, either single color or multicolor yarn can be spun using
2o the present invention. Single color yarn may be spun by mixing one or
more color additive concentrate systems (e.g., a yellow system and blue
system as exemplified above) with the entire host polymer such that a
one color yarn (e.g., a multifilamentary yarn containing only green
filaments) results.
21919~~
8
Multicolor yarn (e.g., heather yarn) may be spun by selectively
coloring separated portions of the host polymer and keeping each
separated portion segregated until spun. For example, a portion of the
host polymer might be colored with both the yellow and the blue additive
s systems to produce green filaments. Another portion of the host polymer
might be colored with a red additive system to produce red filaments
which are spun concurrently with the green filaments. The resulting
multifilamentary yarn will therefore exhibit a heathered color due to the
combination of individual red and green filaments present in the yarn.
The concepts above apply also to the spinning of filaments having
multiple cross-sectional domains, such as core-sheath filaments, pie
wedge filaments, side-by-side filaments and the tike. Thus, for
multidomain filaments, the additive concentrate system may be mixed
with one or more split flows of the host polymer and then recombined with
the remainder of the host polymer flow to achieve filaments having the
additive present only in one or more of the cross-sectional domains.
When the additive is a colorant, therefore, a virtually unlimited
2o number of multicolored, multidomain filaments can be produced. For
example, only the core of a core-sheath filament may include one or more
colorant additives which imparts to the fiber a color attribute that is
visibly
perceptible through the uncolored sheath. In this regard, it has been
found that colorant additives) contained only in the core of a core-sheath
multidomain filament results in a color intensity that is achieved with
reduced colorant loading levels (e.g., between about 5 to about 10% less)
9
as compared to filaments having the same colorant additives)
homogeneously dispersed throughout the entire filament cross-section to
achieve comparable color intensity.
Alternatively or additionally, the colorant additive may be present in
the sheath of a core-sheath filament so as to achieve a color effect that is
a combination of the core and sheath colors. Thus, by selectively
choosing and incorporating colorants into the core and/or sheath, virtually
any color attribute can be achieved for the resulting filament. Some
particular combinations of colorants in both the core and sheath of a
core-sheath filament may not necessarily result in a "pure" color
combination of such colorants being realized for the filament. That is, the
additivelsubtractive effects of colorants in the core and sheath of
core-sheath filaments are relatively complex and sometimes cannot be
~ s predicted with absolute certainty. However, routine experimentation with
colorants in the core and/or sheath of core-sheath filaments will result in
virtually an unlimited number of desired filament color attributes being
obtained.
2o Other multiple domain filament combinations are envisioned, such
as side-by-side domain filaments having different color attributes in each
of the sides or pie wedge filaments whereby one or more of the wedges
have the same or different color attributes. Such multiple domain
filaments may be usefully employed to form heather yarns since the color
25 additive-containing domains will visually present themselves at different
locations along the length of the filaments when twisted (e.g., as may
219199Q
occur during yarn processing). Furthermore, the colorants and domains
in which such colorants are present can be selected to achieve filaments
which macroscopically appear to be uniformly colored.
s Furthermore, although the additive concentrate systems of this
invention may be metered (dosed) into the host polymer (whether in its
entirety or in one or more of its split flows) at a substantially constant
rate,
periodic or continual variance of the dose rate is also envisioned. Thus,
as noted briefly above, when changing from one filament recipe to
another, one or more of the additive concentrates will need to be varied in
order to switch filament production from a former recipe to the then
current recipe. A random or constant dosage rate variance can also be
practiced, however, in which case the resulting filaments will have more
or less of the additive distributed along its length. When the additive is a
~s colorant, such a technique allows filaments to be formed having a
stub-like color appearance along its axial length which may be employed,
for example, to produce yarns having a striated or marbled impression.
These and other aspects and advantages of this invention will
2o become more clear after careful consideration is given to the following
detailed description of the preferred exemplary embodiments thereof.
2191999
11
BRIEF DESCRIPT10N OF THE ACCOMPANYING DRAWING
Reference will hereinafter be made to the accompanying drawing
wherein FIGURE 1 is a schematic view of a filament melt-spinning
apparatus in which the additive system of this invention may be added to
a melt flow of polymeric material prior to spinning.
DETAILED DESCRIPT10N OF THE PREFERRED
EXEMPLARY EMBODIMENTS
To promote an understanding of the principles of the present
invention, descriptions of specific embodiments of the invention follow
and specific language describes the same. It will nevertheless be
understood that no limitation of the scope of the invention is thereby
intended, and that such alterations and further modifications, and such
further applications of the principles of the invention as discussed are
contemplated as would normally occur to one ordinarily skilled in the art
to which the invention pertains.
Thus, for example, while reference has been, and will hereinafter
be, made to melt-spinning of filaments, it will be understood that other
operations which serve to shape a melt of a polymeric material to a final
form (e.g., extrusion or injection molding, blow-molding or the like) are
contemplated. Furthermore, for ease of reference, the discussion which
follows will emphasize the presently preferred embodiment of the
invention in terms of incorporating colorants into polymeric materials, but
CA 02191990 1999-12-29
12
the present invention can likewise be employed to incorporate virtually
any other conventional additive as may be desired. In this regard, the
term "pigment" as used herein and in the accompanying claims is meant
to refer to virtually any material that may be added physically to a polymer
melt flow, and thus generically encompasses colorant pigments which
will be emphasized in the discussion which follows. Thus, suitable
pigments which may be employed in the practice of this invention include
solid and liquid colorants, stabilizers, delusterants, flame retardants,
fillers, antimicrobial agents, antistatic agents, optical brighteners,
extenders, processing aids and other functional additives.
As used herein and in the accompanying claims, the term "color"
includes Munsell Values between about 2.51 to about 8.5/ and Munsell
Chromas greater than about /0.5. (Kelly et al, The ISCC-NBS Method of
~ 5 Designating Colors and a Dictionary of Color Names, National Bureau of
Standards Circular 553, pp. 1-5 and 16 (1955) .
The host polymer in which the additive concentrate system of this
2o invention may be incorporated includes any synthetic thermoplastic
polymer which is melt-spinnable. Exemplary polymers are polyamides
such as poly(hexamethylene adipamide), polycaprolactam and
polyamides of bis(4-aminocyclohexyl) methane and linear aliphatic
dicarboxylic acids containing 9, 10 and 12 carbon atoms; copvlyamides;
2s polyester such as poly(ethylene)terephthalic acid and copolymers thereof;
polyolefins such as polyethylene and polypropylene; and polyurethanes.
CA 02191990 1999-12-29
13
Both heterogeneous and homogeneous mixtures of such polymers may
also be used.
I. Additive Concentrate Preparation
s As noted above, the additive concentrate system employed in the
practice of the present invention is a dispersion or solution of pigment in a
nonaqueous liquid or liquefied polymeric carrier. The pigment may be a
solid particulate (e.g., a colorant) which is coated with a dispersant for
physical dispersion in the carrier material. Alternatively, the pigment may
~o be in a form which is soluble with the carrier, in which case the
dispersant is not necessarily employed. Thus, the pigment may
homogeneously be suspended andlor solubilized in the carrier.
Although a variety of pigments may be employed in the practice of
~5 the present invention, it is presently preferred that the pigment is a
particulate colorant pigment having a mean particle size of less than
Nm, preferably less than about 5 Nm, and most preferably between
0.1 Nm to about 2 Nm.
2o If present, the preferred dispersants which may be employed in the
practice of this invention are the water solubleldispersible polymers as
described in U.S. Patent No. 3,846,507. One particularly useful
dispersant in this class is a copolymer of caprolactam/hexamethylene-
diamine/isophthalic acid/sodium salt of sulfoisophthalic acid having a
25 molecular weight of about 7,000, a specific gravity (H20=1 ) of about 1.1,
2191994
14
a solubility in water of about 25% at 20°C. This preferred water
soluble/dispersible polyamide copolymer dispersant is manufactured by
BASF Corporation and will hereinafter be referenced as "C-68".
Other useful dispersants that may be employed in the practice of
this invention are water solubleldispersible polyesters. One particularly
preferred polyester which is completely dispersible in water is
commercially available from Eastman Chemical Products, Inc., Kingsport,
Tennessee, under the product name "LB-100". This preferred water
~o soluble/dispersible polyester has a specific gravity (Hz0=1 ) of about
1.08,
and is available commercially as a 30% solution of the polyester in water.
Other water soluble/dispersible polymers that may be useful in the
practice of the present invention include, but are not limited to other water
~5 soluble/dispersible polyamides and copolymers thereof, water
soluble/dispersible polyesters and copolymers thereof, water
soluble/dispersible vinyl polymers and copolymers thereof, water
soluble/dispersible alkylene oxide polymers and copolymers thereof and
water soluble/dispersible polyolefins and copolymers thereof, as well as
2o mixtures of the same. Other dispersants, like monomeric dispersants,
may be suitable for use with the present invention.
One presently preferred technique for producing the additive
dispersion of this invention uses as a starting material the aqueous
25 dispersion formed according to the above-referenced Jones '645 patent.
The aqueous dispersion may then be bead-milled and subjected to a
CA 02191990 1999-12-29
spray drying operation so as to remove the aqueous component. The
resulting dispersant-coated pigment granules (hereinafter more simply
referred to as the "dispersible pigment granules") in powder form are then
mixed with a nonaqueo'us liquid polymeric carrier material.
5
The carrier material can be virtually any material that is liquid at or
below melt-spinning temperatures of the polymeric host material.
Preferably, the carrier material is a polyamide or a polyester. The carrier
material must also be compatible with the thermoplastic polymeric host
material. For example, when providing an additive concentrate system
for incorporation into a nylon-6 polymeric host material, the presently
preferred carrier is polycaprolactone since it is liquid at room
temperatures (20°C). However, carriers that may be liquefied at
elevated
temperatures (e.g., less than about 200°C) are also useable in the
~5 practice of this invention. For example, when providing an additive
concentrate system for incorporation into a nylon-6 polymeric host
material, it is also possible to use copolyamides having a melting point of
less than about 200°C.I One particularly preferred class of such
copolyamides is commercially available under the trade name Vestamelt
2o copolyamides from Huls America Inc. of Piscataway, New Jersey, with
Vestameit 72~being particularly preferred.
One alterative technique to make the additive concentrate system
according to this invention involves mixing the pigment, carrier and, if
2s present, dispersant to form a nonaqueous paste in a one-step process
thereby eliminating the need to prepare an aqueous dispersion which is
* Trademarks
CA 02191990 1999-12-29
16
subsequently spray dried. It is preferred that the dispersant, if present,
and the carrier be premixed prior to addition of the pigment. The mixture
may then be milled so as to obtain a paste which can be introduced
directly into a melt flow of the polymeric host material.
s
The additive concentrate system of this invention may also be
prepared by combining the pigment and the dispersant in a high-intensity
mixer (e.g., a Henschel FM series mixer available commercially from
Henschel Mixers America, Inc. of Houston, Texas) until they are
to intimately mixed. Thereafter, the shear imparted by the mixer is reduced,
and the required mass of carrier is added to yield the additive concentrate
of this invention in paste form.
The dispersants that may be employed in the one-step technique,
1 s in addition to those described above, include polyethylene glycol p-octyl
phenyl ether (Triton X-10(~, polyoxypropylene/ethylene block copolymers
(Pluronic 25R2), alkoxylated diamines (Tetronic 150R1'~, sodium lauryl
sulfate and cationic dispersants (VariQuaf~. The dispersant (i.e., the non-
carrier material), if present, is present in the additive concentrate system
2o in an amount between about 5 to about 100 wt.% based on the weight of
the pigment, and more preferably, between about 40 to about 100 wt.%.
However formed, the additive concentrate system is most
preferably in the form of a flowable paste having a viscosity during
25 introduction into the polymeric host material ranging between about 500
cP to about 500,000 cP, and most preferably between about 1,500 cP to
* Trad~narks
~I919~0
17
about 100,000 cP, at a temperature between about 20°C to about
200°C.
The dispersible additive may be maintained to within an acceptable
viscosity range by application of heat (e.g., by keeping the dispersible
additive in a suitable storage vessel which is jacketed with electrical
s resistance heaters and/or a heat transfer medium).
The additive concentrate system preferably contains pigment in an
amount between about 5 to about 75 wt.%, more preferably between
about 10 to about 65 wt.% based on the weight of the additive
1o concentrate system. The additive concentrate system (the dispersible
additive) itself is incorporated into the polymeric host material at levels
between about 0.01 to about 15 wt.%, more preferably between about
0.05% and 10.0 wt.% based on the total weight of the polymeric host
material and additive concentrate system.
II. FILAMENT PRODUCT10N
Accompanying FIGURE 1 schematically depicts a filament
spinning operation 10 by which additive concentrate systems may
selectively be mixed with a melt flow of polymeric host material
2o discharged from a conventional screw extruder 12 and supplied to an inlet
of the spin pack assembly 14. More specifically, the polymeric host
material is introduced into the upstream polymer filter section 14a of the
spin pack assembly before being extruded through orifices in the
spinneret 14b to form additive-containing filaments 16. Prior to reaching
the spinneret 14b, the polymeric host material may be distributed by a
plurality of thin distribution plates 14c in accordance with the above-noted
CA 02191990 1999-12-29
18
U.S. Patent No. 5,162,074 to William H. Hills, which may or may not have
one or more static mixing plates, for example, as disclosed in U.S. Patent
No. 5,137,369 to John A. Hodan.
Batches of the additive concentrate systems in paste form are
respectively held within portable tanks 18a-18d. In the accompanying
FIGURE 1, tanks 18a-18d are shown supported on wheeled carts
20a-20d, respectively, so as to permit each of the tanks 18a-18d to be
~o replaced easily with stand-by tanks containing a fresh supply of the same
or different additive concentrate system. However, other means can be
employed which allow the tanks 18a-18d to be portable, such as
in-ground or overhead conveyance systems, cranes and the like.
Preferably, the additive concentrate system contained in each of the
~5 tanks 18a-18d is different -- that is, tanks 18a-18d may each contain a
different pigment or pigment mixture so that selective incorporation of
each will result in the desired properties being achieved for the filaments
16.
2o Specifically, the tanks 18a-18c may each respectively contain
dispersible colorant pigments corresponding to selected colors such as
aqua, magenta and yellow, while tank 18d may have a specially
formulated tint color (e.g., white, black or the like) to achieve the desired
color hue, chroma and/or intensity. The differently colored additive
25 concentrates held within the tanks 18a-18d may thus be volumetrically
dosed or mixed with the polymeric host material so as to achieve a
19
virtually unlimited number of resulting colors of the melt-spun filaments
16. In a like manner, other filament properties may be "engineered" by
selective incorporation of other non-colorant pigments.
s The carts 20a-20d also support a primary pump 22a-22d and a
metering pump 24a-24d, respectively. The pumps 22a-22d and 24a-24d
are most preferably gear-type pumps which serve to force the additive
concentrate system paste through respective supply lines 26a-26d to the
spin pack assembly 14. More specifically, the primary pumps 22a-22d
serve to maintain a relatively constant input pressure to the immediately
downstream respective metering pump 24a-24d. The primary pumps
22a-22d are therefore relatively larger capacity as compared to their
respective downstream metering pump 24a-24d.
~ 5 The additive concentrate system paste within each of the tanks
18a-18d is maintained under constant agitation in order to prevent
sedimentation of the pigment therein. Such agitation may be
accomplished by a motor-driven mixer 26a-26d and/or via recycle lines
28a-28d (andlor lines 30a-30d). Of course, if the pigment is in solution
2o with the carrier, then such agitation may not be needed.
The metering pumps 24a-24d are variable speed so as to achieve
variable volumetric outputs within their respective capacity range stated
previously. The speed of the metering pumps 24a-24d is most preferably
2s controlled by a logic programmable controller LPC. Specifically, for a
given "recipe" (for example, a desired color for the pigmented filaments
2191999
16) input into the controller LPC, appropriate outputs will be issued to one
or more of the metering pumps 24a-24d to cause them to operate at a
speed to achieve a desired volumetric output for their particular
dispersible additive. Thus, it will be recognized that for certain desired
5 colors, some but not all of the metering pumps 24a-24d will be supplying
paste from their respective tanks 18a-18d to the spin pack assembly 14
andlor may be operated at different speeds to achieve different
volumetric outputs. Suffice it to say, that by selectively controlling the
operation of the metering pumps 24a-24d and, when operated, their
1o respective speed (and hence their respective volumetric outputs),
selective volumetric paste doses can be continuously supplied to the spin
pack assembly 14 where the respective additive concentrate systems will
be homogeneously mixed with the melt flow of polymeric host material
being fed by the extruder 12 via line 32.
The respective speed of one or more of the metering pumps
24a-24d may also be varied continually to thereby respectively vary the
volumetric dose of one or more of the colorant systems over time. Such
speed (dose) variance will thereby cause more or less additive
2o concentrate system being incorporated into the filament per unit time
where results in a filament having varying amounts of the additive per unit
length. In the context of color additives, such speed variance may be
employed so as to form filaments having a randomly striated or marbled
color appearance.
2191990
21
The additive concentrate pastes from lines 26a-26d are most
preferably introduced directly into the spin pack assembly 14 at a location
corresponding to the distributionlmixing section 14c -- that is, at a location
downstream of the polymer filter 14a, but upstream of the spinneret 14b.
In this manner, a relatively quick additive change between successive
batches of filaments 16 is possible (i.e., to allow for changes in additive
recipe to be realized from one filament batch to another). In addition,
such an inlet location for the additive concentrates also allows for a wide
range of processing flexibility to be achieved. For example, the additive
1o pastes from tanks 18a, 18b, 18c andlor 18d may be mixed with the
entirety of polymeric host material supplied via line 32 so that all of the
filaments 16 have the same color. Alternatively, the distribution/mixing
section 14c of the spin pack assembly 14 may be so provided to split the
flow of polymeric host material with one or more of the additive
~s concentrate pastes being mixed with one or more of such split flows to
achieve, for example, multiple differently colored filament groups which
may remain segregated to form single color yarns or may be combined to
form multicolor yarns, such as in a heather yarn. In addition, several
additives may be mixed with the host polymer so that, for example, single
2o color yarns having multiple additive concentrations therein may be
produced from the same spinning equipment. Similarly, one or more
additive concentrate pastes may be mixed with split flows of polymeric
host material within the distributionlmixing section 14c of the spin pack
assembly 14 to achieve multifilamentary yarns having differently colored
25 filaments (e.g., as may be desired to produce yarns having a heathered
appearance).
m9~~~o
22
Although accompanying FIGURE 1 (and the description above)
shows the additive concentrate system pastes being preferably
introduced into the melt flow of polymeric host material directly into the
spin pack assembly 14 at a location between the polymer filter section
14a and the spinneret 14b, it will be understood that the pastes may be
incorporated into the melt flow of polymeric host material at any location
upstream of the spinneret 14b. Thus, for example, the additive system
pastes may be incorporated into the melt flow of polymeric host material
by feeding through an injection port associated with the extruder 12
1o and/or through a port in line 32. Thus, for example, the additive system
pastes may be introduced to the polymeric host material at or
downstream of the extruder throat, but upstream of the spinneret 14b.
Different batches of colored filaments 16 may thus be produced
~5 continuously by simply changing the recipe in the controller LPC and
allowing a sufficient time interval to elapse to ensure that any residual
amounts of the additive concentrate system pastes associated with the
prior recipe have been purged from the spin pack assembly 14. While
some off-specification filament will ensue during the change-over to the
2o new recipe, its economic impact is small by comparison to complete
shut-down of the spinning operation. Furthermore, since relatively small
amounts of the additive concentrate system pastes will residually be
present in the spin pack assembly 14 at the time of recipe change-over,
only a relatively short time interval is needed to purge the spin pack
25 assembly of the prior additive recipe and begin producing filaments
pigmented with the new recipe.
219199Q
23
III. Examples
The following nonlimiting examples will provide a further
understanding of this invention.
In this regard, carpet samples formed of filaments colored in
accordance with the present invention and filaments colored in
accordance with conventional extruder melt-blending techniques were
1o tested according to the following procedures and, where applicable, a
subjective rating scale of between 1 to 5 was utilized (5 being the best
rating):
Yarn Degradation: Data representative of yarn
~ 5 strengthlelongation before and after 100, 200 and 300 hours ultraviolet
radiation exposure according to AATCC Test Method 16-1993, Option E.
Colorfastness: Yarn color/visual data after 100, 200 and 300
hours ultraviolet radiation exposure according to AATCC Test Method
20 16-1993, Option E.
Taber Abrasion Test: ASTM D3884-92.
Crocking: AATCC Test Method 8-1989.
219199
24
~Iposure to 50% Bleach: Carpet samples were cut into two
4.5" x 9" squares. 25 ml of a bleach solution containing about 2.6%
sodium hypochlorite (50% Clorox~ brand bleach and water) was poured
into the center of one sample to form a test region approximately 2" in
diameter. The sample was allowed to air dry for 24 hours after which it
was rinsed with a hot detergentlwater solution containing 12 parts water
and 1 part detergent. The rinsed sample was air dried for 24 hours after
which it was visually rated on a scale of 1 to 5 against the untreated
sample using AATCC Gray Scale in a Macbeth light booth (daylight
setting).
Visual Grades After Exposure to Ozone: AATCC Test Method
129-1990.
~s Visual Grades After Exposure to NOZ: AATCC Test Method
164-1992.
D~yr Heat Ex osure: Samples are heated in a laboratory oven
(1600 Watts, Model No. OV-490, Blue M. Electric Co., Blue Island, Illinois)
2o at 280°F and 320°F and removed after ten minutes. The samples
are
allowed to cool and visually rated on a scale of 1 to 5 using AATCC Gray
Scale.
Tetrapod Wear: ASTM D5251-92.
2s
CA 02191990 1999-12-29
Exanr,~e 1
Dispersant-coated pigment particles were prepared using the
components noted in Table A below. The components were blended
5 using a high shear dissolver type mixer. A water soluble polyamide
dispersant polymer (C-68 manufactured by BASF Corporation in
accordance with U.S. Patent No. 3,846,507 except that
poly(e-caprolactam) was used as a starting material instead of
e-caprolactam) was first dissolved in water to prepare a 25 percent stock
solution. Pigment dispersions were then bead-milled with 2 mm glass
beads for three passes through the mill and were thereafter spray-dried.
The dispersions were spray-dried using a Niro FSD*Pilot unit, which had
a 1.5 meter diameter, 0.8 meters cylinder height, 40° cone, and a
fluidized bed collector at the bottom of the chamber. Dispersions were
~5 fed into the dryer with a two-fluid, externally-mixed nozzle. The spray-
dryer was run with 253-263 ° C inlet and 67-103 ° C outlet
temperatures.
The spray-dried powder tended to be dusty, and thus a fluidized bed
collector was used to increase agglomerate size and thereby reduce the
dust.
Pigment in % Disl~ersant in
a ous ueo s
P_~gment Dis ep Vision Dj~a~sion
Inorganic Yellow ~ 32.5 ~ 13.0
Organic Blue ~ 20.0 ~ 15.0
Organic Red ~ 20.0 ~ 15.0
* Trademark
CA 02191990 1999-12-29
26
Inorganic Tan 30.0 12.0
Organic Green 25.0 12.5
Organic Black 20.0 15.0
WhiteIStabilizer 32.5 I 13.0
example 2
Example 1 was repeated except that a water-dispersible polyester
(LB-100 from Eastman Chemical Products, Inc.) was used as the
1o dispersant polymer in the amounts noted in Table B below. Unlike
Example 1 above, all dispersions according to this Example 2 contained
5.0% of a polyoxypropylene-polyoxyethylene block copolymer surfactant
(Pluronic~ 2582 surfactant from BASF Corporation). Spray-dried
dispersions using LB-100 as the dispersant were not dusty, and were
prepared using the Niro* spray-dryer which was not equipped with a
fluidized bed collector. The Niro spray dryer was run with 220°C inlet
and
80-95°C outlet temperatures. These dispersions were fed into a rotary
wheel type atomizer running at 18,500 rpm.
2o TABI~"E B
Pigment in % Dispersant
in
o s eou
Pigment ~iscersion Dispersion
Organic Blue 27.5 20.6
Organic Red 27.5 20.6
Inorganic Tan 32.5 ~ 13.0
* Trademark
CA 02191990 1999-12-29
27
Organic Green ~ 32.5 24.7
Organic Black 25.0 18.7
White . 40.0 16.0
White/Stabilizer ~ 40.0 16.0
Example 3
The additive concentrate pastes in Table C below were prepared
by first melting at 150°C 50-60% of the required copolyamide carrier
1o polymer (Vestamelt 722*from Huls America Inc.). The spray-dried
powders obtained according to Example 1 above were then bag-blended
in desired ratios to achieve desired final colors and stirred into the molten
carrier polymer. The balance of the carrier polymer needed was then
added and stirred into the concentrate blend formulation. The spray-dried
powders tended to form large agglomerates which did not disperse
without extended agitation. Thus, the blends were stirred overnight
(approximately 10 to 12 hours) prior to yarn extrusion.
The white/stabilizer pigments used in the blended pigment ratios
2o for all final colors, except Gray and Light Gray, were not the spray dried
coated pigments obtained according to Example 1. Instead, the
white/stabilizer pigments were compounded with Vestamelt 722 polymer
using a vented twin screw compounding extruder to obtain chip
concentrates having 25 wt.% of white pigment and 25 wt.% stabilizer.
The chip concentrates of such white/stabilizer pigments were then
* Trademark
219199Q
28
blended in desired ratios with certain of the spray-dried pigments
obtained in Example 1 to achieve the final colors noted below in Table C.
TABLE C
Total % Pigment
in
Final Color Paste
Light Gray 13.9
Gray 9.3
Black 20.4
Light Green 20.0
Purple 25.3
Blue 19.0
Light Tan 19.8
Mauve 18.7
Green 19.0
B rows 19. 7
2o EXAMPLE 4
The additive concentrate pastes in Table D below were prepared
following the procedures of Example 3 above, except that the spray-dried
powders obtained from Example 2 were used, and the carrier was
polycaprolactone. Unlike Example 3, no compounded chips of
2s white/stabilizer pigments were used.
CA 02191990 1999-12-29
29
Total % Pigme,~~t
Final Colos 'n ste
Light Gray 37.0
Gray 37.8
Black 34.0
Light Green 39.0
Purple 35.5
1 o Blue 34.8
Light Tan 35.0
Mauve 30.5
Green 34.9
Brown 37.7
Example 5
A Barmag 6E extruder was used for filament yarn extrusion with
the additive concentrate pastes in Table C being fed downstream of the
2o extruder at around 150°C in desired ratias to achieve the filament
color
noted below in Table E. The resulting melt-spun filament yarns were
6-hole pentagonal cross-section, 715 +/- 15 denier, and 14 filaments/end.
Eight ends of these undrawn yarns were combined during draw texturing
to prepare 2250/112 denier yarns which were then two-ply cable-twisted
to make 4500/224 denier carpet yarns. The carpet yarns were then tufted
* Tradgnarx
30
into 1/10 gauge, 26 ounces/square yard, 3/16" pile height level loop
carpets.
The carpets were then tested to determine various physical
s properties using the testing methods and techniques described
previously. The results of such testing are tabulated below in Tables 1-4
and are presented in comparison to carpets formed of "control" filaments
of matching color. The "control" filaments were made using conventional
compounded pigment chips which were melt-blended with the polymeric
~o host chip in an extruder, with the melt-blend then being fed to the
spinneret.
Table E
Additive Concentrate% Additive
Paste Components Concentrate
Other
Final Color Than Stabilizer Paste in Filament
Light Gray black, white, green,1.4
blue
Gray black, white, blue, 2.6
red
Black black, white 3.8
Light Green black, white, green,1.4
tan
Purple black, white, blue, 2.6
red
Blue black, white, blue, 2.8
red
Light Tan black, green, tan 1.7
Mauve black, blue, red 2.8
Green black, green, blue 4.2
Brown black, white, red, 6.5
tan
31
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32
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219199
34
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219193f~
EXAMPLE 6
Example 5 was repeated except that the additive concentrate
pastes of Table D were fed at the extruder throat at ambient temperature
(about 20°C). The paste components and the amount of paste in the
filaments are noted below in Table F. The resulting filaments were
formed into carpets and tested similar to Example 5. The results appear
in Tables 5-8 below.
Table F
~~dditive Concentrate% Additive
Paste Components Concentrate
Other
Final Than Stabilizer Paste in Filament
Color
Light black, white, green,0.6
Gray blue
Gray black, white, blue, 0.7
red
Black black, white 2.2
Light black, white, green,0.8
Green tan
Purple black, white, blue, 2.0
red
Blue black, white, blue, 1.6
red
Light black, green, tan 1.0
Tan
Mauve black, blue, red 1.9
Green black, green, blue 2.2
Brown black, white, red, 3.6
tan
21~~,~~0
'° 3 6
0
L
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2191990
37
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38
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2191990
2191990
39
Table 8. Carpet visual ratings after exposure to dry heat and Tetrapod wear.
Test Samples made with LB-100
Dry Heat 500 K
Exposure in Tetrapod
280 F 320 F Stair End
TAN_CTRL_B 4-5 4 3 3
TAN_PCL 4-5 4 3 ~ 3
LT GRAY CTRL E 4-5 3 3 3
LT GRAY_PCL 4-5 3 3 3
~
LT 4-5 3-4 3 3
GREEN CTRL B
LT GREEN_PCL 4-5 4 3 3
GRAYaCTRL_B 4-5 4 3 3
GRAY_PCL 4-5 4 3 3
BLACK CTRL B 5 5 3-4 4
BLACK_PCL 5 _ 3-4 ~ 3-4
5
_GREEN CTRL B 5 4-5 2-3 3-
~ 4
_
GREEN_ 5 4-5 3-4 _
PCL 3-4
BLUE CTRL B 5 4-5 3-4 3-4
BLUE_PCL 4-5 4 3-4 3-4
PURPLE_CTRL B 4-5 4 3-4 3-4
PURPLE PCL 4-5 4 3-4 3-4
CA 02191990 1999-12-29
The data in Tables 1-8 above demonstrate that the performance
properties of carpet yarns made from pigmented filaments of this
invention are comparable to carpet yarns which are colored according to
the conventional practice of melt-blending pigmented chips with base
5 polymer chips. It is surprising that the incorporation of the low
molecular-weight polymer as the carrier in the dispersible additive did not
affect either the breaking strength or elongation of the pigmented
filaments of this invention when compared to conventional melt-colored
filaments.
EXAMPLE 7
A tan additive concentrate paste was formed by direct blending of
40 wt.% tan pigment particles, 8 wt.% of polyethylene glycol p-octyl
~ 5 phenyl ether (Triton X-10~) dispersant, and 52 wt. % polycaprolactone.
The resulting additive concentrate paste was preheated to approximately
140°C and exhibited a viscosity of between 2000 to 4000 cP. The paste
was pumped directly into a spin pack assembly at a location downstream
of the polymer filter but upstream of the spinneret orifices (58 hole
2o asymmetrical trilobal). The additive concentrate paste was mixed with the
nylon-6 polymeric host material within the spin pack assembly at a rate of
between about 6.0 glmin (to obtain about 0.8-1.1 wt.% pigment in the
resulting melt-spun filaments) to about 7.3 g/min (to obtain about 1.1-1.5
wt.% pigment in the resulting melt-spun filaments). The resulting
2s melt-spun filaments had a uniformly colored appearance along the
lengthwise extent as viewed with an unaided eye. Microscopic views of
* Traci~nark
2191990
41
filament cross-sections revealed that substantially homogenous to
somewhat striated mixing had occurred in dependence upon the injection
rate of the additive paste.