U.S. patent application number 10/651444 was filed with the patent office on 2005-03-03 for thermoplastic fibers exhibiting durable high color strength characteristics.
Invention is credited to Cowan, Martin E., Dai, Sonya, Morin, Brain G., Royer, Joseph R..
Application Number | 20050048281 10/651444 |
Document ID | / |
Family ID | 34217401 |
Filed Date | 2005-03-03 |
United States Patent
Application |
20050048281 |
Kind Code |
A1 |
Royer, Joseph R. ; et
al. |
March 3, 2005 |
Thermoplastic fibers exhibiting durable high color strength
characteristics
Abstract
Improvements in permitting brighter colorations within
polypropylene fibers and/or yarns while simultaneously providing
more efficient production methods of manufacturing of such colored
fibers as well are provided. Generally, such fibers and/or yarns
have been colored with pigments, which exhibit dulled results, or
dyes, which exhibit high degrees of extraction and low levels of
lightfastness. Such dull appearances, high extraction levels, and
less than stellar lightfastness properties negatively impact the
provision of such desirable colored polypropylene fibers and/or
yarns which, in turn, prevents the widespread utilization of such
fibers and yarns in various end-use applications. Thus, it has
surprisingly been determined that brighter colorations, excellent
extraction, and more-than-acceptable lightfastness characteristics
can be provided, preferably, through manufacture with certain
polymeric colorants that include poly(oxyalkylene) groups thereon.
Fabric articles comprising such novel fibers and/or yarns are also
encompassed within this invention.
Inventors: |
Royer, Joseph R.;
(Greenville, SC) ; Dai, Sonya; (Spartanburg,
SC) ; Morin, Brain G.; (Greenville, SC) ;
Cowan, Martin E.; (Spartanburg, SC) |
Correspondence
Address: |
Milliken & Company
P. O. Box 1927
Spartanburg
SC
29304
US
|
Family ID: |
34217401 |
Appl. No.: |
10/651444 |
Filed: |
August 30, 2003 |
Current U.S.
Class: |
428/364 |
Current CPC
Class: |
D02G 3/346 20130101;
Y10T 428/2913 20150115 |
Class at
Publication: |
428/364 |
International
Class: |
D02G 003/00 |
Claims
What we claim is:
1. A thermoplastic fiber comprising a liquid colorant present
therein, wherein said liquid colorant exhibits a rod-like structure
within said fiber.
2. The fiber of claim 1 wherein said liquid colorant is a polymeric
colorant.
3. The fiber in claim 1 wherein said thermoplastic is selected from
the group consisting of at least one polyolefin, any polyolefin
copolymers thereof, at least one polyester, any polyester
copolymers thereof, at least one polyamide, any polyamide
copolymers thereof, and any blends thereof.
4. The fiber in claim 3 wherein said thermoplastic is selected from
the group consisting of at least one polyolefin, any polyolefin
copolymers thereof, at least one polyester, any polyester
copolymers thereof, at least one polyamide, any polyamide
copolymers thereof, and any blends thereof. wherein said
thermoplastic is a polyolefin selected from the group consisting of
polypropylene, polyethylene, any copolymers thereof, and any blends
thereof.
5. The fiber in claim 3 wherein said fiber is present as a
structure selected from the group consisting of a monofilament
fiber, a tape fiber, a staple fiber, a melt spun non-woven fiber, a
bicomponent/splittable fiber, and a slit film fiber.
6. The fiber in claim 4 wherein said fiber is present as a
structure selected from the group consisting of a multifilament
fiber, a monofilament fiber, a tape fiber, a staple fiber, a melt
spun non-woven fiber, a bicomponent/splittable fiber, and a slit
film fiber.
7. The fiber in claim 1 wherein said fiber is textured.
8. The fiber in claim 2 wherein said fiber is textured.
9. The fiber in claim 3 wherein said fiber is textured.
10. The fiber in claim 4 wherein said fiber is textured.
11. The fiber in claim 5 wherein said fiber is textured.
12. The fiber in claim 6 wherein said fiber is textured.
13. A multifilament yarn comprising at least one fiber as defined
in claim 1.
14. A multifilament yarn comprising at least one fiber as defined
in claim 2.
15. A multifilament yarn comprising at least one fiber as defined
in claim 3.
16. A multifilament yarn comprising at least one fiber as defined
in claim 4.
17. A multifilament yarn comprising at least one fiber as defined
in claim 5.
18. A multifilament yarn comprising at least one fiber as defined
in claim 6.
19. A multifilament yarn comprising at least one fiber as defined
in claim 7.
20. A multifilament yarn comprising at least one fiber as defined
in claim 8.
21. A multifilament yarn comprising at least one fiber as defined
in claim 9.
22. A multifilament yarn comprising at least one fiber as defined
in claim 10.
23. A multifilament yarn comprising at least one fiber as defined
in claim 11.
24. A multifilament yarn comprising at least one fiber as defined
in claim 12.
25. The fiber in claim 7 wherein said fiber is a bulk continuous
filament.
26. The fiber in claim 8 wherein said fiber is a bulk continuous
filament.
27. The fiber in claim 9 wherein said fiber is a bulk continuous
filament.
28. The fiber in claim 10 wherein said fiber is a bulk continuous
filament.
29. The fiber in claim 111 wherein said fiber is a bulk continuous
filament.
30. The fiber in claim 12 wherein said fiber is a bulk continuous
filament.
31. The fiber in claim 1 wherein said fiber comprises at least one
nucleator compound.
32. The fiber in claim 2 wherein said fiber comprises at least one
nucleator compound.
33. The fiber in claim 1 wherein said fiber comprises at least one
pigment.
34. The fiber in claim 2 wherein said fiber comprises at least one
pigment.
35. The fiber in claim 33 wherein said pigment is titanium
dioxide.
36. The fiber in claim 34 wherein said pigment is titanium
dioxide.
37. The fiber in claim 33 wherein said fiber comprises at least one
ultraviolet absorber.
38. The fiber in claim 34 wherein said fiber comprises at least one
ultraviolet absorber.
39. A fabric comprising at least one fiber as defined in claim
1.
40. A fabric comprising at least one fiber as defined in claim
2.
41. A fabric comprising at least one fiber as defined in claim
3.
42. A fabric comprising at least one fiber as defined in claim
4.
43. A fabric comprising at least one fiber as defined in claim
5.
44. A fabric comprising at least one fiber as defined in claim
6.
45. A fabric comprising at least one fiber as defined in claim
7.
46. A fabric comprising at least one fiber as defined in claim
8.
47. A fabric comprising at least one fiber as defined in claim
9.
48. A fabric comprising at least one fiber as defined in claim
10.
49. A fabric comprising at least one fiber as defined in claim
11.
50. A fabric comprising at least one fiber as defined in claim
12.
51. A fabric comprising at least one multifilament yarn as defined
in claim 13.
52. A fabric comprising at least one multifilament yarn as defined
in claim 14.
53. A fabric comprising at least one multifilament yarn as defined
in claim 15.
54. A fabric comprising at least one multifilament yarn as defined
in claim 16.
55. A fabric comprising at least one multifilament yarn as defined
in claim 17.
56. A fabric comprising at least one multifilament yarn as defined
in claim 18.
57. A fabric comprising at least one multifilament yarn as defined
in claim 19.
58. A fabric comprising at least one multifilament yarn as defined
in claim 20.
59. A fabric comprising at least one multifilament yarn as defined
in claim 21.
60. A fabric comprising at least one multifilament yarn as defined
in claim 22.
61. A fabric comprising at least one multifilament yam as defined
in claim 23.
62. A fabric comprising at least one multifilament yarn as defined
in claim 24.
63. The fiber in claim 3 wherein said thermoplastic is a
polyester.
64. The fiber in claim 4 wherein said thermoplastic is
polyester.
65. The fiber in claim 63 wherein said fiber is textured.
66. The fiber in claim 64 wherein said fiber is textured.
67. A fabric comprising the fiber of claim 63.
68. A fabric comprising the fiber of claim 64.
69. A fabric comprising the fiber of claim 65.
70. A fabric comprising the fiber of claim 66.
Description
FIELD OF THE INVENTION
[0001] This invention relates to improvements in permitting
brighter colorations within thermoplastic fibers and/or yarns while
simultaneously providing more efficient production methods of
manufacturing of such colored fibers as well. Generally, such
fibers and/or yarns have been colored with pigments, which exhibit
dulled results, or dyes, which exhibit high degrees of extraction
and low levels of lightfastness. Such dull appearances, high
extraction levels, and less than stellar lightfastness properties
negatively impact the provision of such desirable colored
thermoplastic (such as, without limitation, polypropylene) fibers
and/or yarns which, in turn, prevents the widespread utilization of
such fibers and yarns in various end-use applications. Thus, it has
surprisingly been determined that brighter colorations, excellent
extraction, and more-than-acceptable lightfastness characteristics
can be provided through manufacture with certain polymeric
colorants that include poly(oxyalkylene) groups thereon. Fabric
articles comprising such novel thermoplastic fibers and/or yarns
are also encompassed within this invention.
DISCUSSION OF THE PRIOR ART
[0002] All U.S. patents cited below are herein entirely
incorporated by reference.
[0003] Thermoplastic fibers have been utilized many years for
myriad different fabric and textile applications. In particular,
polyolefin, polyester, and polyamide fibers have been prominent as
replacements for naturally occurring fibers (such as cotton and
wool, for instance) due to lower costs, more reliability in supply,
physical properties, and other like benefits. Colorations have been
available for such thermoplastic, synthetic fibers in order to
provide aesthetic, identification, and other properties. Such
colorations have been mostly provided through pigments that
thoroughly color the target fibers and exhibit sufficiently high
lightfastness and crocking characteristics that use thereof has not
been curtailed. Dyeing within baths is available for already-formed
fabrics (such as knit, woven, and/or non-woven textiles), if a
solid color is desired, and also for yarns with selected properties
through package dyeing procedures. However, accent yarns or other
fibers that require individual colorations requires coloring during
production. In addition, some polymers such as polypropylene,
polyethylene, etc., have not been heretofore able to accept dyes of
any kind, and have thus been colored with pigment. Thus, although
such pigment colorants are prevalent and generally effective at
providing color within such thermoplastic fibers, there are certain
drawbacks for which improvements have been unavailable. For
example, pigments are notoriously capable of staining fiber
manufacturing/extrusion machinery such that control of
discolorations within subsequently produced fibers is rather
difficult, and the time required to change colors is high. Also,
pigments impart a dulling appearance, a lack of brightness, and a
low luster, all believed to be due to the solid nature of such
coloring agents. In addition, pigment size and dispersion limits
the processability of small fibers, which are desirable for their
improved touch and feel. Thus, improvements in such areas are
desirable for coloring agents to be introduced within thermoplastic
fibers.
[0004] In particular, it has been found that improvements in
coloring individual polyolefin fibers are needed. For instance,
there has been a continued desire to utilize low denier
polypropylene fibers in various different products, such as apparel
(due to highly effective soft hand properties), and the like.
Polyolefin fibers exhibit excellent strength characteristics,
highly desirable hand and feel, and do not easily degrade or erode
when exposed to certain "destructive" chemicals. However, even with
such impressive and beneficial properties and an abundance of
polyolefin (such as polypropylene, polyethylene, and the like),
which is relatively inexpensive to manufacture and readily
available as a petroleum refinery byproduct, such fibers are not
widely utilized in products that require fiber and/or yarn
colorations therein. Specifically, although polyesters (such as
polyethylene terephthalate, or PET) and polyamides (such as nylons)
are generally more expensive to manufacture, such fibers do not
exhibit the same unacceptable color disadvantages inherent within
polyolefins. This is due in large part to the difficulties inherent
in providing sufficiently bright colorations within such target
polyolefin fibers and/or yarns in general. Thus, it is imperative
to provide remedies to such issues to permit utilization of such
lower cost polymer materials in greater varieties of end-uses.
[0005] Pigments, the most prevalent of polyolefin fiber colorants
utilized throughout the fabric industry, as noted above, are, as is
well-known, solid particles that require a relatively high amount
to provide sufficiently deep colorations within such target
materials. Because such pigments exhibit colorations within the
discrete areas in which they are actually present, complete pigment
presence is required to fully color such target fibers and/or
yarns. If certain discrete areas of such target materials do not
include any or insufficient amounts of pigments, streaks, uneven
colorations, and other aesthetically displeasing results will most
likely result. Hence, proper color provision via pigment presence
within polyolefin fibers and/or yarns requires large amounts of
such solid particles to accord the needed level of colorations
therein. However, with such a large amount of pigment present
within such target fibers and/or yarns comes an inevitable dull
appearance as well. Without intending to be limited to any specific
scientific theory, it has now been hypothesized by the inventors
that such a dull appearance is attributable to the lack of
transparency through the target fiber and/or yam within which such
pigments are added. The solid nature of such pigment particles
basically appears to fill the entire fiber and/or yam to the extent
that light cannot pass through easily. Thus, the visible color
provided by the fiber and/or yarn is limited to that portion of the
scattered light that is reflected back to the viewer alone. As
such, the color appears dull to the eye thereby compromising the
resultant brightness effect of the fiber, and the ultimate fabric
within which such a fiber is incorporated. Thus, there exists the
need to provide a distinct improvement on dullness (brightness) in
this type of situation in order to permit utilization of more
brightly colored polyolefin fibers and/or yarns in order to permit,
in turn, more aesthetically pleasing fabric articles from a
coloration perspective. Furthermore, and just as important, such
pigments are extremely difficult to purge from within manufacturing
machinery, particularly within fiber extrusion units, such that
once a new color is desired for target fiber materials, extensive
purging is required for proper cleaning. Such cleaning is generally
quite extensive and complicated since a small amount of residual
pigment anywhere within the machinery can discolor any amount of
extruded fiber therein. Thus, utilization of either potentially
harmful solvents, in-depth and invasive cleaning procedures
throughout the entire unit, and/or wasteful flushing processes that
also potentially result in pigment effluent production within
wastewater, and the norm rather than the exception for
pigment-colored polypropylene methods.
[0006] Dyes have also been utilized to color not only polyolefin
fibers and/or yarns, but also materials such as nylon, polyesters,
cotton, and other fiber types. As noted above, in general,
polyolefins are an economically superior fiber as compared with
other synthetic types (polyesters, nylons, for example); however,
its widespread use has been limited due to such issues as this
coloration problem. Thus, although dyes have provided bright
colorations in these other types of fibers, extraction and
lightfastness issues have, again, severely limited utilization of
such coloring agents within polyolefins. In essence, such soluble
coloring agents do not react readily within polyolefin without
exhibiting migration and extraction over time. Polyesters and
nylons, as examples, include reactive groups that permit reaction
therein with dyes (sulfonated types, for example) and which in turn
do not exhibit appreciable extraction as a result. Within
polyolefins, to the contrary, extraction levels are quite high for
such dyes and thus unevenness in color, streaking, if not complete
loss in color, are typical results. This problem is further
amplified when fabrics made therefrom such dyed polyolefins are
subjected to laundering treatments. Lightfastness (the ability of
the target fibers and/or yarns to retain their desired color
levels, if not colors at all) are generally unacceptable as well
when dyes are utilized without having excessive amounts of
protecting agents (UV absorbers, for example) added in addition.
Furthermore, the same machinery staining issues and potential
wastewater problems are present with dyes as well, albeit to a
lesser degree because of the liquid nature of such coloring agents.
In any event, a certain degree of difficulty still exists within
liquid dye processing within polyolefin fiber and/or yam
manufacturing (extruding, for example) due to such staining
characteristics. Thus, as for pigments above, efficiency is
compromised during fiber manufacture such that any cost benefits of
utilizing polyolefin as compared with other synthetic fiber and/or
yam types are reduced to a level that is unacceptable for
displacement within the fabric industry.
[0007] In addition, with pigment coloring of fibers, the pigments
are normally matched to a standard shade in a high concentration
masterbatch that is then diluted with uncolored polymer during the
fiber manufacture. As such, if there is a problem or mismatch
between the color masterbatch, there is only limited adjustment
available at the fiber manufacturing stage. This often necessitates
re-manufacture of the masterbatch, adding expense and delaying the
manufacturing process.
[0008] All in all, it is evident that polyolefin has suffered from
coloring limitations in the past such that displacement of more
expensive fiber types has not been forthcoming and that the
standard coloring agents utilized today have neither imparted the
necessary brightness, extraction levels, lightfastness properties,
and low staining characteristics that appear to be the main
obstacles to more widespread use of colored polypropylene fibers
within the fabric industry. To date, there simply has not been any
coloring agent that has accorded necessary bright colorations,
excellent low (if not nonexistent) extraction levels, and superior
lightfastness results within the polypropylene fiber and/or yam
industry.
DESCRIPTION OF THE INVENTION
[0009] It is thus an object of the invention to provide
thermoplastic (such as polypropylene, as one non-limiting example)
fibers and/or yarns that exhibit extremely bright and aesthetically
pleasing colorations as compared to pigmented products. A further
object of the invention is to provide such colorations that are of
very low, if nonexistent, extraction. A further object of the
invention is to provide a specific method for the production of
brightly colored thermoplastic fibers that permits quick and
efficient changeover from one colorant to another. Additionally,
another object of this invention is to provide a brightly colored
thermoplastic fiber and/or yarn that exhibits outstanding
lightfastness properties, either alone or in the presence of
minimal amounts of UV absorber additives. Another object of the
invention is to provide a process for manufacturing fibers using
liquid colors in which the shade can be adjusted to match some
standard.
[0010] Accordingly, this invention encompasses a colored
thermoplastic fiber compromising a liquid colorant present therein
in a rod-like configuration. Furthermore, this invention
encompasses a colored thermoplastic fiber including at least one
liquid colorant therein, wherein said at least one liquid colorant
therein exhibits a very low extraction and crocking level
therefrom. Additionally, this invention encompasses a method of
producing a colored thermoplastic fiber including the steps of a)
providing a molten thermoplastic formulation, optionally including
colored thermoplastic concentrates therein, wherein said
concentrates comprise at least one liquid polymeric colorant; and
b) extruding said thermoplastic formulation of step "a" within a
fiber extrusion line to form a colored thermoplastic fiber,
wherein, optionally at least one liquid polymeric colorant is
simultaneously injected within said fiber extrusion line during
extrusion of said thermoplastic formulation of step "a"; and.
Optionally, this process has the additional steps of providing
multiple liquid color constituents in step "a" or "b", matching the
resulting fibers to a standard, and adjusting the ratio of the
multiple liquid color constituents so provided to adjust the color
of the resulting fiber to match the standard. This invention also
encompasses the formation of a colored film including such liquid
polymeric colorants, and the formation of colored tape fibers
therefrom.
[0011] As used herein, the term "thermoplastic" is intended to mean
a polymeric material that will melt upon exposure to sufficient
heat but will retain its solidified state, but not prior shape
without use of a mold or like article, upon sufficient cooling.
Specifically, as well, such a term is intended solely to encompass
polymers meeting such a broad definition that also exhibit either
crystalline or semi-crystalline morphology upon cooling after
melt-formation through the use of the aforementioned mold or like
article. For this invention, however, the thermoplastic is to be
utilized to from fibers and/or yarns through any number of
techniques, including, without limitation, extrusion (for
multifilament and monofilament types), spinning, water- and/or
air-quenching, spun-bonded and/or melt-blown non-woven products,
staple fibers, bicomponent/splittalbe fibers, tape and/or ribbon
fibers (through slit film procedures, as one example), and the
like. Particular types of polymers contemplated within such a
definition include, without limitation, polyolefins (such as
polyethylene, polypropylene, polybutylene, and any combination
thereof), polyamides (such as nylon), polyurethanes, polyesters
(such as polyethylene terephthalate), polylactic acids, and any
copolymers of these broad types, either within the same
classification or not. Polypropylene fibers are most preferred,
although polyesters are preferred as well. The particular
polypropylene fiber and/or yarn of this invention may be of any
denier, including microdeniers (below about 1.5 denier per fiber)
or higher deniers 1.5 denier per fiber or higher), as merely
examples.
[0012] The target fibers and/or yarns may also be textured in any
manner commonly followed for polypropylene materials. One example
of this is false-twist texturing, in which a twist is imparted to
the fiber through the use of spindles, and while the fiber is in
the twisted state it is heated and then cooled to impart into the
individual filaments a memory of the twisted state. The yarn is
then untwisted, but retains bulk due to the imparted memory. In
another texturing embodiment, known as bulked continuous filament
(BCF), the yarn is pushed with air jets into a stuffer box where it
is crowded in a non-uniform state with other fibers and heated to
retain the memory of this non-uniform state. The yarn is then
cooled, but again retains bulk due to the imparted memory. Of
course, other texturing methods, such as air texturing, gear
texturing, and the like, may be used.
[0013] The term "polypropylene" is intended to encompass any
polymeric composition comprising propylene monomers, either alone
or in mixture or copolymer with other randomly selected and
oriented polyolefins, dienes, or other monomers (such as ethylene,
butylene, and the like). Such a term also encompasses any different
configuration and arrangement of the constituent monomers (such as
syndiotactic, isotactic, and the like). Thus, the term as applied
to fibers is intended to encompass actual long strands, tapes,
threads, and the like, of drawn polymer. The polypropylene may be
of any standard melt flow (by testing); however, standard fiber
grade polypropylene resins possess ranges of Melt Flow Indices
between about 1 and 1000.
[0014] Contrary to standard manufacturing procedures and techniques
for plaques, containers, sheets, and the like (such as taught
within U.S. Pat. No. 4,016,118 to Hamada et al., for example),
fibers clearly differ in structure since they must exhibit a length
that far exceeds its cross-sectional area (such, for example, its
diameter for round fibers). Fibers are extruded and drawn; articles
are blow-molded or injection molded, to name two alternative
production methods. Also, the crystalline morphology of
polypropylene within fibers is different than that of standard
articles, plaques, sheets, and the like. For instance, the dpf of
such polypropylene fibers is at most about 5000; whereas the dpf of
these other articles is much greater. Polypropylene articles
generally exhibit spherulitic crystals while fibers exhibit
elongated, extended crystal structures. Thus, there is a great
difference in structure between fibers and polypropylene articles
such that any predictions made for spherulitic particles (crystals)
of colored polypropylene articles do not provide any basis for
determining the effectiveness of coloring agents as additives
within polypropylene fibers. For instance, plaques made with
pigments can exhibit bright, deep shades, and still appear
transparent. In fiber form, dullness (low brightness) and opacity
are prominent when deep shades of pigmented fibers are produced.
Thus, the significant differences in form and structure between
sheet-like articles and fibers (and/or yarns) of the same
thermoplastic, make it difficult to predict how effective a
specific coloring agent may perform within one through knowledge of
the other.
[0015] The coloring agents particularly useful within this
invention are those that are liquid in nature, preferably, though
not necessarily, polymeric in nature [i.e., poly(oxyalkylenated)]
to the extent that, upon introduction within such target
polypropylene fibers, extraction therefrom is severely limited, if
not nonexistent. The term "liquid" is intended to mean that such
colorants are liquid at room temperature and standard pressure
(25.degree. C. at 1 atmosphere). Example colorants that meet these
limitations (and thus are defined by the term "liquid polymeric
colorants" herein) are those that are available from Milliken &
Company under the tradename CLEARTINT.RTM.. Alternatively, liquid
dyestuffs may also be utilized, although less preferred than
polymeric types.
[0016] The preferred colorants in this general class are
represented by the following formula (I):
R{A[(B).sub.n].sub.m}.sub.x (I)
[0017] wherein
[0018] R is an organic chromophore;
[0019] A is a linking moiety in said chromophore selected from the
group consisting of N, O, S, SO.sub.2N, and CO.sub.2;
[0020] B is an alkyleneoxy constituent contains from 2 to 4 carbon
atoms;
[0021] n is an integer of from 2 to about 500;
[0022] m is 1 when A is O, S, or CO.sub.2, and m is 2 when A is N
or SO.sub.2N; and
[0023] x is an integer of from 1 to about 5.
[0024] The molecular weight of such colorants are at least 2000
and, due to the high oxyalkylenation present, are highly water
soluble and liquid at room temperature. The organic chromophore is,
more specifically, one or more of the following types of compounds:
azo, diazo, disazo, trisazo, diphenylmethane, triphenylmethane,
xanthene, nitro, nitroso, acridine, methine, styryl, indamine,
thiazole, oxazine, stilbene, or anthraquinone. In an alternative
embodiment, the chromophore may be optically inactive, at least
within the visible spectrum, but absorb uv radiation, as one
example, thereby imparting ultraviolet protection to the target
fibers. Preferably, R is one or more of azo, diazo,
triphenylmethane, methine, anthraquinone, or thiazole based
compounds. Such a group may produce coloring effects that are
evident to the eye; however, optical brightening chromophores are
also contemplated in this respect. Group A is present on group R
and is utilized to attach the polyoxyalkylene constituent to the
organic chromophore. Nitrogen is the preferred linking moiety. The
polyoxyalkylene group is generally a combination of ethylene oxide
and propylene oxide monomers. Preferably propylene oxide is present
in the major amount, and most preferably the entire polyoxyalkylene
constituent is propylene oxide.
[0025] The preferred number of moles (n) of polyoxyalkylene
constituent per polyoxyalkylene chain is from 2 to 50, more
preferably from 10 to 30. Also, preferably two such polymeric
chains are present on each polymeric colorant compound (x, above,
is preferably 2). In actuality, the number of moles (n) per
polymeric chain is an average of the total number present since it
is very difficult to control the addition of specific numbers of
moles of alkyleneoxy groups. The Table below lists the particularly
preferred colorants (with the range of alkoxylation present on the
colorant listed due to the inexactness of production of specific
chain lengths) for utilization in relation to Structure (I),
above:
1 COLORANT TABLE Preferred Poly(oxyalkylenated) Colorants Col. # R
A B(with moles) m x Color 1 Methine N 6-8 EO; 12-15PO 2 1 Yellow 2
Benzothiazole N 6-8 EO; 10-12 PO 2 1 Red diazo 3 Triphenylmethane N
2-4 EO; 12-15 PO 2 2 Cyan 4 Aminothiophene N 10-12 EO; 12-15 PO 2 1
Violet Diazo 5 Phenyl Diazo N 8-10 EO; 10-12 PO 2 2 Orange
[0026] Such colorants provide the aforementioned, highly desirable,
low extraction properties, as well as the significant bright
colorations as compared with pigmented fibers.
[0027] Without intending on being limited to any specific
scientific theory, it appears that such colorants are capable of
complete introduction within the target polypropylene fibers to the
extent that transparent thin rod-like configurations of the liquid
colorants are present within the fibers after extrusion. Such
configurations thus permit an even distribution of color throughout
the target fiber, and, apparently, with a strong cohesive nature
while present therein said fibers, such thin rod-like
configurations are not amenable to easy migration from therein
either. In other words, although small openings may exist within
and/or at the surface of such extruded polypropylene fibers, the
rod-like configurations of the colorants therein do not break, but
appear to keep there rod-like appearance and the liquid colorant
thus does not migrate or escape through such surface openings, even
if such fibers come into contact with adhesive surfaces themselves.
Such a physical appearance is shown within the drawings discussed
below. In essence, empirically the liquid colorants (polymerics,
preferably, although possible liquid dyestuffs may function
similarly) will appear as long strands of color within extruded
fibers if the methods of producing disclosed herein are employed
when viewed at proper magnifications (such as from 300 to
1000.times.; proper viewing may be seen most readily between 500
and 600.times.). Cross-sectionally, such long strands will appear
as small dots within the target fibers. These dots will be the tops
of these rod-like structures which can then be noticed from side
views as the aforementioned strands. Thus, since these strands are
basically pools of liquid color stretched during the fiber
extrusion process, these structures will exhibit aspect ratios
(length to diameter) of from 10:1 to 500,000:1, preferably from
50:1 to 100,000:1, more preferably from 50:1 to 10,000:1, and most
preferably from 100:1 to 1,000:1. Thus, the term rod-like is
intended to encompass these high aspect ratio strands of liquid
color within target thermoplastic fibers. Since the thermoplastic
will be colorless, or at least sufficiently different in color from
the added liquid coloring agent, it is relatively easy to view such
rod-like structures through side views coupled with cross-sectional
views. Again, the continuous strands of color or easily viewed from
the side; the "dots" of tops of different strands are easily viewed
in cross-section.
[0028] This rod-like configuration also provides effective and even
colorations throughout such target fibers because of the ability of
light to pass through such fibers and transparent film-like
structures simultaneously. Thus, light is transmitted through such
fibers as well as absorbed by the colorants therein due to the
transparent appearance of the resultant fiber. The resultant
appearance is, unexpectedly, very bright in nature, much more so,
for example, than the empirical appearance of the above-discussed
pigmented fibers that require a large amount of solid particles
therein to provide even colorations throughout, but which, as a
result, also exhibit very dull appearances as well. The colored
transparent nature available with these inventive liquid colorants
produces the bright colorations, much like a colored filter placed
over a light imparts a bright, colored effect when the light shines
therethrough. The fibers themselves are generally solid in nature,
and, cross-sectionally, appear as round, triangular, square, and/or
rectangular in shape, but may have any cross sectional shape, such
as octalobal which is popular in carpet fibers.
[0029] Such fibers (or yarns comprising such fibers) may also
include the presence of certain compounds that quickly and
effectively provide rigidity and/or tensile strength to the target
polypropylene fiber to a level heretofore unavailable, particularly
in terms of permitting high-speed spinning for greater efficiency
in fiber and/or yarn manufacturing. Generally, these compounds
include any structure that nucleates polymer crystals within the
target polypropylene after exposure to sufficient heat to melt the
initial pelletized polymer and upon allowing such a melt to cool.
The compounds must nucleate polymer crystals at a higher
temperature than the target polypropylene without the nucleating
agent during cooling. In such a manner, the nucleator compounds
provide nucleation sites for polypropylene crystal growth which, in
turn, appear to provide thick lamellae within the fibers themselves
which, apparently (without intending on being bound to any specific
scientific theory) increase the processability of the target fibers
to such a degree that the tensions associated with high-speed
spinning can easily be withstood. The preferred nucleating
compounds include dibenzylidene sorbitol based compounds, as well
as less preferred compounds, such as sodium benzoate, certain
sodium and lithium phosphate salts (such as sodium
2,2'-methylene-bis-(4,6-di-tert-butylphenyl)phospha- te, otherwise
known as NA-11 or NA-21), zinc glycerolate, and others. Sodium
benzoate, in general, is not preferred because it is known to
outgas corrosive benzoic acid, among other deficiencies. Also, the
amount of nucleating agent present within the inventive fiber is at
least 10 ppm; preferably this amount is at least 100 ppm; and most
preferably is at least 1250 ppm. Any amount of such a nucleating
agent should suffice to provide the desired shrinkage rates after
heat-setting of the fiber itself; however, excessive amounts (e.g.,
above about 10,000 ppm and even as low as about 6,000 ppm) should
be avoided, primarily due to costs, but also due to potential
processing problems with greater amounts of additives present
within the target fibers.
[0030] Another potentially preferred class of nucleators suitable
for incorporation within the inventive colored fibers include
saturated metal or organic salts of bicyclic dicarboxylates,
preferably saturated metal or organic salts of bicyclic
dicarboxylates, preferably, bicyclo[2.2.1]heptane-dicarboxylates,
or, generally, compounds conforming to Formula (I) 1
[0031] wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5,
R.sub.6, R.sub.7, R.sub.8, R.sub.9, and R.sub.10 are individually
selected from the group consisting of hydrogen, C.sub.1-C.sub.9
alkyl, hydroxy, C.sub.1-C.sub.9 alkoxy, C.sub.1-C.sub.9
alkyleneoxy, amine, and C.sub.1-C.sub.9 alkylamine, halogen,
phenyl, alkylphenyl, and geminal or vicinal carbocyclic having up
to nine carbon atoms, R' and R" are the same or different and are
individually selected from the group consisting of hydrogen,
C.sub.1-C.sub.30 alkyl, hydroxy, amine, polyamine, polyoxyamine,
C.sub.1-C.sub.30 alkylamine, phenyl, halogen, C.sub.1-C.sub.30
alkoxy, C.sub.1-C.sub.30 polyoxyalkyl, C(O)--NR.sub.11C(O)O--R'",
and C(O)O--R'", wherein R.sub.1 is selected from the group
consisting of C.sub.1-C.sub.30 alkyl, hydrogen, C.sub.1-C.sub.30
alkoxy, and C.sub.1-C.sub.30 polyoxyalkyl, and wherein R'" is
selected from the group consisting of hydrogen, a metal ion (such
as, without limitation, Na.sup.+, K.sup.+, Li.sup.+, Ag+ and any
other monovalent ions), an organic cation (such as ammonium as one
non-limiting example), polyoxy-C.sub.2-C.sub.18-alkylene,
C.sub.1-C.sub.30 alkyl, C.sub.1-C.sub.30 alkylene, C.sub.1-C.sub.30
alkyleneoxy, a steroid moiety (for example, cholesterol), phenyl,
polyphenyl, C.sub.1-C.sub.30 alkylhalide, and C.sub.1-C.sub.30
alkylamine; wherein at least one of R' and R" is either
C(O)--NR.sub.11C(O)O--R'" or C(O)O--R'", wherein if both R' and R"
are C(O)O--R'" then R'" both R' and R" may be combined into a
single bivalent metal ion (such as Ca.sup.2+, as one non-limiting
example) or a single trivalent metal overbase (such as Al--OH, for
one non-limiting example). Preferably, R' and R" are the same and
R'" is either Na.sup.+ or combined together for both R' and R" and
Ca.sup.2+. Other possible compounds are discussed in the preferred
embodiment section below.
[0032] Preferably, as noted above, such a compound conforms to the
structure of Formula (II) 2
[0033] wherein M.sub.1 and M.sub.2 are the same or different and
are independently selected from the group consisting of metal or
organic cations or the two metal ions are unified into a single
metal ion (bivalent, for instance, such as calcium, for example),
and R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7,
R.sub.8, R.sub.9, and R.sub.10 are individually selected from the
group consisting of hydrogen, C.sub.1-C.sub.9 alkyl, hydroxy,
C.sub.1-C.sub.9 alkoxy, C.sub.1-C.sub.9 alkyleneoxy, amine, and
C.sub.1-C.sub.9 alkylamine, halogen, phenyl, alkylphenyl, and
geminal or vicinal carbocyclic having up to 9 carbon atoms.
Preferably, the metal cations are selected from the group
consisting of calcium, strontium, barium, magnesium, aluminum,
silver, sodium, lithium, rubidium, potassium, and the like. Within
that scope, group I and group II metal ions are generally
preferred. Among the group I and II cations, sodium, potassium,
calcium and strontium are preferred, wherein sodium and calcium are
most preferred. Furthermore, the M.sub.1 and M.sub.2 groups may
also be combined to form a single metal cation (such as calcium,
strontium, barium, magnesium, aluminum, including monobasic
aluminum, and the like). Although this invention encompasses all
stereochemical configurations of such compounds, the cis
configuration is preferred wherein cis-endo is the most preferred
embodiment. The preferred embodiment polyolefin articles and
additive compositions for polyolefin formulations comprising at
least one of such compounds, broadly stated as saturated bicyclic
carboxylate salts, are also encompassed within this invention.
[0034] As they apply to this invention, then, the terms
"nucleators", "nucleator compound(s)", "nucleating agent", and
"nucleating agents" are intended to generally encompass, singularly
or in combination, any additive to polypropylene that produces
nucleation sites for polypropylene crystals from transition from
its molten state to a solid, cooled structure. Hence, since the
polypropylene composition (including nucleator compounds in certain
cases) must be molten to eventually extrude the fiber itself, the
nucleator compound will provide such nucleation sites upon cooling
of the polypropylene from its molten state. The only way in which
such compounds provide the necessary nucleation sites is if such
sites form prior to polypropylene recrystallization itself. Thus,
any compound that exhibits such a beneficial effect and property is
included within this definition. Such nucleator compounds more
specifically include dibenzylidene sorbitol types, including,
without limitation, dibenzylidene sorbitol (DBS),
monomethyldibenzylidene sorbitol, such as
1,3:2,4-bis(p-methylbenzylidene) sorbitol (p-MDBS), dimethyl
dibenzylidene sorbitol, such as 1,3:2,4-bis(3,4-dimethylbenzylid-
ene) sorbitol (3,4-DMDBS); other compounds of this type include,
again, without limitation, sodium benzoate, NA-11, NA-21, bicyclic
dicarboxylate salts, and the like. The concentration of such
nucleating agents (in total) within the target polypropylene fiber
is at least 100 ppm, preferably at least 1250 ppm. Thus, from about
100 to about 5000 ppm, preferably from about 500 ppm to about 4000
ppm, more preferably from about 1000 ppm to about 3500 ppm, still
more preferably from about 1500 ppm to about 3000 ppm, even more
preferably from about 2000 ppm to about 3000 ppm, and most
preferably from about 2500 to about 3000 ppm.
[0035] Also, without being limited by any specific scientific
theory, it appears that the potential, but not required, nucleators
which perform the best are those which exhibit relatively high
solubility within the propylene itself. Thus, compounds which are
readily soluble, such as 1,3:2,4-bis(p-methylbenzylidene) sorbitol
provides the lowest shrinkage rate for the desired polypropylene
fibers. The DBS derivative compounds are considered the best
shrink-reducing nucleators within this invention due to the low
crystalline sizes produced by such compounds. Other nucleators,
such as NA-11, also impart acceptable characteristics to the target
polypropylene fiber in terms of, for example, withstanding high
speed spinning tensions; however, apparently due to poor dispersion
of NA-11 in polypropylene and the large and varied crystal sizes of
NA-11 within the fiber itself, the performance is less consistent
than for the highly soluble, low crystal-size polypropylene
produced by well-dispersed 3,4-DMDBS or, preferably, p-MDBS.
[0036] It has been determined that the nucleator compounds that
exhibit good solubility in the target molten polypropylene resins
(and thus are liquid in nature during that stage in the
fiber-production process) provide more effective fiber properties
for withstanding high speed spinning tension levels. Thus,
substituted DBS compounds (including DBS, 3,4-DMDBS, and,
preferably p-MDBS) appear to provide fewer manufacturing issues as
well as lower shrink properties within the finished polypropylene
fibers themselves. Although 3,4-DMDBS is preferred for such low
denier fibers, any of the above-mentioned nucleators may be
utilized within this invention. Mixtures of such nucleators may
also be used during processing in order to provide such spinning
efficiencies and low-shrink properties as well as possible
organoleptic improvements, facilitation of processing, or cost.
[0037] In addition to those compounds noted above, sodium benzoate
and NA-11 are well known as nucleating agents for standard
polypropylene compositions (such as the aforementioned plaques,
containers, films, sheets, and the like) and exhibit excellent
recrystallization temperatures and very quick injection molding
cycle times for those purposes. The dibenzylidene sorbitol types
exhibit the same types of properties as well as excellent clarity
within such standard polypropylene forms (plaques, sheets, etc.).
For the purposes of this invention, it has been found that the
dibenzylidene sorbitol types are preferred as nucleator compounds
within the target polypropylene fibers.
[0038] Furthermore, such fibers may include other coloring agents,
such as pigments, titanium dioxide, and the like, as well as fixing
agents for lightfastness purposes. To that end, certain ultraviolet
absorbers provide excellent protection from ultraviolet radiation
and thus aids in reducing, if not preventing, color degradation due
to such exposure. Any type of ultraviolet absorber compound or
formulation that is dispersible within thermoplastics may be
utilized within this invention. However, some non-limiting examples
of such components include phenolic antioxidants, such as
HOSTANOX.RTM. 245, O10, O14, O16, O3, and blends with HOSTANOX.RTM.
M, all available from Clariant; processing stabilizers, such as
HOSTANOX.RTM. PAR 24, SANDOSTAB.RTM. PEPQ (from Clariant), and
blends with SANDOSTAB.RTM. QB; sulfur-containing co-stabilizers,
such as HOSTANOX.RTM. SE 4 or SE 10; metal deactivators, such as
HOSTANOX.RTM. OSP 1; light stabilizers, such as NYLOSTAB.RTM. S-EED
(from Clariant, as well); and straightforward ultraviolet
absorbers, such as CHIMAS SORB.RTM. 2020, 944, 119, and/or 119FL,
TINUVIN.RTM. 783, 353, 234, 1577, and/or 622 (all available from
Ciba Specialty Chemicals). Preferred is TINUVIN.RTM. 783 for such a
purpose.
[0039] In terms of providing effective colorations for brightness,
it is further desirable to avoid pigments as nucleating agents;
however, if desired, slight amounts of such pigments may be added
for nucleation or coloration purposes if such are desired end
results. Other additives may also be present, including antistatic
agents, brightening compounds, clarifying agents, antioxidants,
antimicrobials (preferably silver-based ion-exchange compounds,
such as ALPHASAN.RTM. antimicrobials available from Milliken &
Company), fillers, and the like. Furthermore, any fabrics made from
such inventive fibers may be, without limitation, woven, knit,
non-woven, in-laid scrim, any combination thereof, and the like.
Additionally, such fabrics may include fibers other than the
inventive polypropylene fibers, including, without limitation,
natural fibers, such as cotton, wool, abaca, hemp, ramie, and the
like; synthetic fibers, such as polyesters, polyamides,
polyaramids, other polyolefins (including non-low-shrink
polypropylene), polylactic acids, and the like; inorganic fibers
such as glass, boron-containing fibers, and the like; and any
blends thereof.
[0040] In addition, this invention can be practiced with any melt
extrudable thermoplastic polymer, such as polyester, nylon, poly
lactic acid, and the like, with similar results.
[0041] Such inventive fibers can be included in a fabric such as a
carpet, upholstery fabric, woven fabric, knit fabric, nonwoven,
pile fabric, netting, and the like. In addition, these fibers can
be combined in such fabric structures as accent yarns, especially
if the additional non-inventive fibers are dye accepting. In such a
case, the inventive yarns provide accent yarns with bright
appearance. In addition, individual yarns may be incorporated
within non-fabric structures, such as, as one non-limiting example,
fishing lures, and other end-uses in which brightly colored strong
fibers are desirable.
[0042] Inventive yarns and fibers can be used in any standard
textile process, including, without limitation, such methods as yam
texturing processes such as stuffer box, bulk continuous filament
(BCF), air jet texturing, twisting, false twist testing, and the
like. They can also be combined with other yarns or used in other
processes to make "elegant" or "fancy" yarns, such as chenille,
slub yarns, stria yarns, etc., with all of the incumbent advantages
of combining the technologies. In addition, the transparent nature
of the color can be used in light weight fabrics to make colored
transparent fabrics such as may be desirable to show a pattern on a
substrate covered by the inventive fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate a potentially
preferred embodiment of producing the inventive low-shrink
polypropylene fibers and together with the description serve to
explain the principles of the invention wherein:
[0044] FIG. 1 is a schematic of the potentially preferred method of
producing colored polypropylene fibers through typical spinning
machinery.
[0045] FIG. 2 is a schematic of the potentially preferred method of
producing colored polypropylene tape fibers.
[0046] FIG. 3 is a schematic of the potentially preferred method of
producing colored polypropylene fibers through typical high-speed
spinning machinery.
[0047] FIG. 4 is a side-view color microphotograph of a
green-colored inventive polypropylene fiber magnified at 565.times.
colored with a liquid polymeric colorant.
[0048] FIG. 5 is a side-view color microphotograph of a comparative
green-colored polypropylene yarn magnified at 565.times. having
pigments present throughout.
[0049] FIG. 6 is a cross-sectional view of a plurality of
green-colored inventive polypropylene fibers magnified at
565.times. colored with a liquid polymeric colorant.
DETAILED DESCRIPTION OF THE DRAWING AND OF THE PREFERRED
EMBODIMENT
[0050] FIG. 1 depicts the non-limiting preferred procedure followed
in producing the inventive low denier polypropylene fibers. The
entire fiber production assembly 10 comprises an extruder 11
including a metering pump (not illustrated) for introduction of
specific amounts of polymer into the extruder 11 (to control the
denier of the ultimate target manufactured fiber and/or yarn) which
also comprises four [five] different zones 12, 14, 16, 18, 20
through which the polymer (not illustrated) passes at different,
increasing temperatures. The molten polymer is mixed with the
liquid polymeric colorant (here, Example 1 from the Colorant Table,
above, preferably) within a mixer zone 22. Basically, the polymer
(not illustrated) is introduced within the fiber production
assembly 10, in particular within the extruder 11. The
temperatures, as noted above, of the individual extruder zones 12,
14, 16, 18, 20 and the mixing zone 22 are as follows: first
extruder zone 12 at 210.degree. C., second extruder zone 14 at
220.degree. C., third extruder zone 16 at 230.degree. C., fourth
extruder zone 18 at 235.degree. C., [fifth extruder zone 20 at
240.degree. C.,] and mixing zone 22 at 240.degree. C. The molten
polymer (not illustrated) then moves into a spinneret area 24 set
at a temperature of 240.degree. C. for strand extrusion. All such
temperatures may be modified as needed, and these levels are
non-limiting and simply potentially preferred. The fibrous strands
28 then pass through an air-blown treatment shroud [area] 26 set at
a temperature of 175.degree. C. and then through a treatment area
29 whereupon a lubricant, such as water or an oil, is applied
thereto the strands 28. The strands 28 are then collected into a
bundle 30 via a take-up roll 32 to form a multifilament yarn 33
which then passes to a series of tensioning rolls 34, 36 prior to
drawing. The yam 33 then passes through a series of two different
sets of draw rolls 38, 40, 42, 44 which increase the speed of the
collected finished strands 33 as compared with the speed of the
initially extruded strands 28. The finished strands 33 extend in
length due to a greater pulling speed in excess of such an initial
extrusion speed within the extruder 11. The strands 33 are then
passed through a series of relax rolls 46, 48 and ultimately to a
winder 50 for ultimate collection on a spool (not illustrated). The
speed of the winder 50 ultimately dictates the speed and efficiency
of the entire apparatus in terms of permitting high speed
manufacturing and spinning (drawing) with minimal, if any, breakage
of the target fibers during such a procedure. The draw rolls are
heated to a very low level as follows: first draw rolls 38, 40
60-70.degree. C. and the second set of draw rolls 42, 44
80-90.degree. C., as compared with the remaining areas of high
temperature exposure as well as comparative fiber drawing
processes. The draw rolls 38, 40, 42, 44 individually and,
potentially independently rotate at a speed of from about 1000
meters per minute to as high as about 5000 meters per minute. The
second draw rolls 42, 44 generally rotate at a higher speed than
the first in excess of about 800 meters per minute up to 1000
meters per minute over those of the first set.
[0051] FIG. 2 depicts the non-limiting preferred procedure followed
in producing the inventive low-shrink polypropylene tape fibers.
The entire fiber production assembly 110 comprises a mixing
manifold 111 for the incorporation of molten polymer and additives
(such as the aforementioned nucleator compound) which then move
into an extruder 112. The extruded polymer is then passed through a
metering pump 114 to a die assembly 116, whereupon the film 117 is
produced. The film 117 then immediately moves to a quenching bath
118 comprising a liquid, such as water, and the like, set at a
temperature from 5 to 95.degree. C. (here, preferably, about room
temperature). The drawing speed of the film at this point is
dictated by draw rolls and tensionsing rolls 120, 122, 124, 126,
128 set at a speed of about 100 feet/minute, preferably, although
the speed could be anywhere from about 20 feet/minute to about 200
feet/minute, as long as the initial drawing speed is at most about
1/5.sup.th that of the heat-draw speed later in the procedure. The
quenched film 119 should not exhibit any appreciable crystal
orientation of the polymer therein for further processing. Sanding
rolls 130, 131, 132, 133, 134, 135, may be optionally utilized for
delustering of the film, if desired. The quenched film 119 then
moves into a cutting area 36 with a plurality of fixed knives 138
spaced at any distance apart desired. Preferably, such knives 138
are spaced a distance determined by the equation of the square root
of the draw speed multiplied by the final width of the target
fibers (thus, with a draw ratio of 5:1 and a final width of about 3
mm, the blade gap measurements should be about 6.7 mm). Upon
slitting the quenched film 119 into fibers 140, such fibers are
moved uniformly through a series of nip and tensioning rolls 142,
143, 144, 145 prior to being drawn into a high temperature oven 146
set at a temperature level of between about 280 and 350.degree. C.,
in this instance about 310.degree. C., at a rate as noted above, at
least 5 times that of the initial drawing speed. Such an increased
drawing speed is effectuated by a series of heated drawing rolls
141, 150 (at temperatures of about 360-400.degree. F. each) over
which the now crystal-oriented fibers 154 are passed. A last
tensioning roll 152 leads to a spool (not illustrated) for winding
of the finished tape fibers 154.
[0052] FIG. 3 depicts the non-limiting preferred procedure followed
in producing the inventive low denier polypropylene fibers. The
entire fiber production assembly 210 comprises an extruder 211
including a metering pump (not illustrated) for introduction of
specific amounts of polymer into the extruder 211 (to control the
denier of the ultimate target manufactured fiber and/or yarn) which
also comprises five different zones 212, 214, 216, 218, 220 through
which the polymer (not illustrated) passes at different, increasing
temperatures. The molten polymer is mixed with the nucleator
compound (also molten) within a mixer zone 222. Basically, the
polymer (not illustrated) is introduced within the fiber production
assembly 210, in particular within the extruder 211. The
temperatures, as noted above, of the individual extruder zones 212,
214, 216, 218, 220 and the mixing zone 22 are as follows: first
extruder zone 212 at 205.degree. C., second extruder zone 214 at
215.degree. C., third extruder zone 216 at 225.degree. C., fourth
extruder zone 218 at 235.degree. C., fifth extruder zone 220 at
240.degree. C., and mixing zone 222 at 245.degree. C. The molten
polymer (not illustrated) then moves into a spinneret area 224 set
at a temperature of 250.degree. C. for strand extrusion. All such
temperatures may be modified as needed, and these levels are
non-limiting and simply potentially preferred. The fibrous strands
228 then pass through an air-blown treatment area 226 and then
through a treatment area 229 whereupon a lubricant, such as water
or an oil, is applied thereto the strands 228. The strands 228 are
then collected into a bundle 230 via a take-up roll 232 to form a
multifilament yam 233 which then passes to a series of tensioning
rolls 234, 236 prior to drawing. The yam 233 then passes through a
series of two different sets of draw rolls 238, 240, 242, 244 which
increase the speed of the collected finished strands 233 as
compared with the speed of the initially extruded strands 228. The
finished strands 233 extend in length due to a greater pulling
speed in excess of such an initial extrusion speed within the
extruder 211. The strands 233 are then passed through a series of
relax rolls 246, 248 and ultimately to a winder 250 for ultimate
collection on a spool (not illustrated). The speed of the winder
250 ultimately dictates the speed and efficiency of the entire
apparatus in terms of permitting high speed manufacturing and
spinning (drawing) with minimal, if any, breakage of the target
fibers during such a procedure. The draw rolls are heated to a very
low level as follows: first draw rolls 238, 240 68.degree. C. and
the second set of draw rolls 242, 244 88.degree. C., as compared
with the remaining areas of high temperature exposure as well as
comparative fiber drawing processes. The draw rolls 238, 240, 242,
244 individually and, potentially independently rotate at a speed
of from about 1000 meters per minute to as high as about 5000
meters per minute. The second draw rolls 242, 244 generally rotate
at a higher speed than the first in excess of about 800 meters per
minute up to 1000 meters per minute over those of the first
set.
[0053] In FIG. 4, the presence of rod-like structures of color is
evident throughout the fiber. Such rod-like structures are
basically the liquid polymeric colorants stretched in the same
manner as the resin fiber is stretched during extrusion. The shear
of extrusion forms long high aspect ratio rod-like configurations
of liquid colorant within the target fiber. Such a rod-like
structure thus imparts colorations to the target fiber while
simultaneously allowing transmission of light therethrough. As
such, the fiber remains transparent to light, thereby exhibiting an
increased brightness and luster. Furthermore, these rod-like
structures, although they remain liquid in nature, are not in
individual pools of color, but are stretched in such a rod-like
manner, such that the liquid component cannot be easily extracted
from within the target fiber without damaging the fiber itself.
[0054] In FIG. 5, the presence of pigment particles is evident
throughout the fiber. Such pigment particles are solid in nature.
The color imparted to the target fiber is thus substantially
reliant upon absorption of light by such solid particles. There is
little chance of light transmission through the fiber such that the
fiber lacks transparency. As a result, brightness and luster are
compromised such that the fiber exhibits a dulling effect,
particularly in comparison with the fiber of FIG. 4.
[0055] In FIG. 6, the presence of "dots" of color can be seen
within the cross-sectional views of the target fibers (as in FIG.
4). Such "dots" are the portions of the rod-like high aspect ratio
structures of the liquid colorants that were stretched during
extrusion. The plurality of "dots" thus shows the inclusion of
numerous different rod-like structures throughout individuals
fibers. Coupled with the side view (as in FIG. 4), it can be seen
how a liquid coloring agent (polymeric type, preferably, though not
necessarily) is stretched from a starting pool of liquid into this
high aspect ratio strand (rod-like structure).
[0056] Inventive Fiber and Yarn Production
EXAMPLE #1
Polymeric Colorant Fibers
[0057] Yarns were made using a commercially available polypropylene
fiber grade resin Amoco 7550 (melt flow of 18), using a standard
fiber spinning apparatus as described previously. The five
colorants from the COLORANT TABLE, above, were formed into 10%
concentrates premixed with fiber grade polypropylene resin and fed
into the hopper of the extruder during fiber extrusion. In one
preferred embodiment, fiber grade resin polypropylene was fed into
the extruder on an Alex James & Associates multifilament fiber
extrusion line as noted above in FIG. 1 along with a 10% color
concentrate including the required liquid polymeric colorants. Yarn
was produced with the extrusion line conditions shown in Table 1
using a 68 hole spinneret, giving a yarn of nominally 150 denier.
The godet roll temperatures were 67.degree. C. (for 38, 40 in FIG.
1), 85.degree. C. (for 42, 44), and 125.degree. C. (for 46, 48),
respectively, with a nominal winder speed of about 1300 m/min.
Pigmented fibers were also made for comparative purposes.
[0058] The extruder and cooling conditions were as follows:
2 Procedural Conditions Table #1 Extruder Temperature Zone #1
210.degree. C. Extruder Temperature Zone #2 220.degree. C. Extruder
Temperature Zone #3 230.degree. C. Extruder Temperature Zone #4
235.degree. C. Mixer Temperature 240.degree. C. Spinneret
Temperature #1 240.degree. C. Spinneret Temperature #2 240.degree.
C. Shroud Temperature 175.degree. C.
[0059] Winder take-up speeds of 1290 m/min with draw ratios of
approximately 3.5 were utilized and deniers between 150 and 200
were produced. A minimum of 3 samples were produced with
concentrations of 12 and or 1% color in the Amoco 7550 for each of
the odors. Extrusion conditions and physical properties of these
samples are detailed in the following tables. Additionally,
comparative pigmented samples were produced with three pigments
provided by Standridge Color Concentrate 86600 blue 25% GSP, fade
red HUV and yellow HG 25% which are identified in the table below
as blue, red and yellow pigment, respectively.
3 Procedural Conditions Table #2 Fiber Extrusion Conditions Color
Draw Heat Set Sample ID Polymer Color Level Ratio (.degree. C.) 1
Amoco 7550 None 0 3.49 125 2 Amoco 7550 None 0 4.56 125 3 Amoco
7550 None 0 3.44 125 4 Amoco 7550 10% Colorant #3 0.5 4.56 125 5
Amoco 7550 10% Colorant #3 0.5 3.44 125 6 Amoco 7550 10% Colorant
#3 0.5 3.53 125 7 Amoco 7550 10% Colorant #5 0.5 3.49 125 8 Amoco
7550 10% Colorant #5 0.5 3.44 125 9 Amoco 7550 10% Colorant #5 0.5
4.56 125 10 Amoco 7550 10% Colorant #2 0.5 3.44 125 11 Amoco 7550
10% Colorant #2 1.0 3.44 125 12 Amoco 7550 10% Colorant #2 1.0 3.44
125 13 Amoco 7550 10% Colorant #2 1.0 3.55 125 14 Amoco 7550 10%
Colorant #4 0.5 3.49 125 15 Amoco 7550 10% Colorant #4 0.5 3.94 125
16 Amoco 7550 10% Colorant #4 0.5 4.56 125 17 Amoco 7550 10%
Colorant #1 0.5 4.56 125 18 Amoco 7550 10% Colorant #1 0.5 3.44 125
19 Amoco 7550 10% Colorant #1 0.5 3.53 125 20 Amoco 7550 Blue
Pigment 0.5 3.44 125 21 Amoco 7550 Red Pigment 0.5 3.44 125 22
Amoco 7550 Yellow Pigment 0.5 3.44 125
[0060]
4 Experimental Table #1 Fiber Properties 3% 130 C Denier Elongation
Tenacity Modulus Shrinkage Sample ID (g/9000 m) (%) (g/den) (g/den)
(%) 1 153.8 53.0 4.6 41.6 6.6 2 85.7 32.1 6.5 67.9 9.9 3 159.7 67.9
4.7 44.4 11.1 4 172.7 61.5 5.0 44.0 14.8 5 147.4 74.4 4.6 42.4 8.5
6 150.7 66.1 4.2 38.9 9.6 7 149.5 41.1 4.4 41.2 7.2 8 155.1 54.7
4.1 38.7 8.0 9 169.2 46.6 5.6 51.0 10.4 10 156.2 51.1 5.0 43.9 13.6
11 181.0 50.0 4.6 42.8 9.0 12 153.8 46.6 4.9 45.3 9.5 13 153.6 35.5
4.8 45.4 13.6 14 154.1 47.7 4.3 39.5 11.2 15 151.4 48.0 4.4 41.8
7.0 16 168.8 27.0 5.3 51.4 15.3 17 177.3 44.8 5.2 46.7 11.5 18
149.9 58.1 4.6 43.4 11.7 19 150.7 48.4 4.6 43.0 14.8 20 153.7 84.7
3.8 35.8 N/A 21 150.7 66.8 3.3 35.8 N/A 22 151.6 40.6 4.3 40.8
N/A
[0061] The above samples have similar physical properties to those
of fibers spun with pigments (solution dyed) in the same
polypropylene resin, however the luster of the colors is
significantly different. It is also important to note that the
polymeric colorants are generally non-nucleating and will, under
the same processing conditions have similar physical properties
while the pigments (specifically the blue pigment--Sample 20)
generally are nucleating which often requires the fiber spinning
equipment to be operated under different conditions to obtain
similar physical properties--note the higher elongation of sample
20 in comparison to samples 21 and 22.
EXAMPLE 2
Polymeric Colorant Fibers with TiO.sub.2 and Pigments
[0062] A series of polypropylene samples was produced under the
standard fiber spinning conditions described in Example 1 to test
the ability to combine both solid pigments and liquid polymeric
colorants in the same fibers. The drawing conditions for these
example yarns are detailed in the following table.
5 Procedural Conditions Table #3 Spinning Conditions Roll Speed
Roll Temperature (m/min) .degree. C. Feed Roll 800 Not heated Draw
Roll 1 805 55 Draw Roll 2 1450 75 Draw Roll 3(A + B) 2000 120 Relax
Roll 1980 Not heated
[0063] Using the standard fiber spinning conditions as described
above, a series of 10 experiments were performed to produce samples
with liquid polymeric colorants labeled by Milliken & Company
Product numbers, and TiO.sub.2 which is commonly used in the
production of thermoplastic fibers to produce dull (9% TiO.sub.2)
and semi-dull (3% TiO.sub.2) appearance. The fibers were
successfully produced at all of the conditions tested and the list
of colorants, TiO.sub.2 levels and fiber properties are detailed in
the Table below using polymeric liquid colorant mixtures available
from Milliken & Company under the tradename CLEARTINT.RTM..
6 Fiber Properties Table #2 Polymeric Color Concentrate 5% Secant
Polymeric Color Level TiO.sub.2 Level Denier Elongation Tenacity
Modulus Sample ID (Color/Number) (%) (%) (g/9000 m) (%) (g/den)
(g/den) T1 Blue 9805 20 N/A 166 50.60 4.626 32.49 T2 Blue 9805 20 9
152 57.20 5.345 37.40 T3 Blue 5603 10 N/A 153 53.44 5.872 42.94 T4
Blue 5603 5 3 157.92 47.75 5.053 39.01 T5 Smoke 9809 10 N/A 161
31.56 4.323 37.81 T6 Smoke 9809 10 3 158 39.79 4.824 37.56 T7 Amber
9808 20 N/A 164 51.38 4.898 36.89 T8 Amber 9808 20 3 161 57.77 4.83
34.70 T9 Green 5062 10 N/A 158 51.81 5.225 40.38 T10 Green 5062 5 3
153 54.55 5.42 40.50
[0064] In addition to experiments with TiO.sub.2 a series of
experiments were conducted to determine the viability of spinning
polypropylene fibers with the liquid polymeric colorants and
standard fiber pigments. A series of 8 experiments, listed in the
table below, were produced under the standard spinning conditions
described above. The pigments, obtained from Standridge Color
Concentrate, Social Circle, Ga., are commercially available and are
typical of the pigments used within the polypropylene fiber
industry. Specifically, the green pigment is identified as SCC
3654, the red pigment is SCC 4591 and the black pigment is SCC
23005. The polymeric colorants in these example experiments are
identified as PP Green 5720, PP Red 5718, and PP Smoke 5719 for the
green, red and black liquid polymeric colorant respectively (all
available under the tradename CLEARTINT.RTM. from Milliken &
Company).
7 Fiber Additives Table #2 Polymer Colorant Pigment TiO2 Sample
Level Level Level ID Color (%) (%) (%) P1 Green 1.8 0 0 P2 Green
1.5 1.5 0 P3 Green 0 1.5 0 P4 Red 0 1.5 9 P5 Red 2 1.5 9 P6 Black 0
1.5 0 P7 Black 2 0 0 P8 Black 2 1.5 0
EXAMPLE 3
Polymeric Colorant Fibers with Nucleators
[0065] A series of experiments were conducted using commercially
available nucleators in combination with the liquid polymeric
colorants (from the COLORANT TABLE, above) to produce continuous
filament fibers. Using the same conditions as described in Example
1 above, 13 samples were produced using a commercially available
polypropylene nucleator, Millad 3940 (MDBS). Fiber compositions for
the 13 experimental samples are found in Fiber Additives Table #3
below and the physical properties of the final fibers are found in
Fiber Properties Table #4.
8 Fiber Additives Table #3 Nucleated Fiber Conditions Additive
Color Heat Level Level Set Draw Sample ID Polymer Additive (ppm)
Color (%) (C.) Ratio A Amoco 7550 M3940 2750 10% Colorant #3 0.5
125 4.0 B Amoco 7550 M3940 2750 10% Colorant #3 0.5 125 5.1 C Amoco
7550 M3940 2750 10% Colorant #3 0.5 125 3.4 D Amoco 7550 M3940 2750
10% Colorant #5 0.5 125 3.4 E Amoco 7550 M3940 2750 10% Colorant #2
0.5 125 4.0 F Amoco 7550 M3940 2750 10% Colorant #2 0.5 125 3.4 G
Amoco 7550 M3940 2750 10% Colorant #2 0.5 125 5.1 H Amoco 7550
M3940 2750 10% Colorant #4 0.5 125 5.1 I Amoco 7550 M3940 2750 10%
Colorant #4 0.5 125 4.0 J Amoco 7550 M3940 2750 10% Colorant #4 0.5
125 3.4 K Amoco 7550 M3940 2750 10% Colorant #1 0.5 125 5.1 L Amoco
7550 M3940 2750 10% Colorant #1 0.5 125 4.0 M Amoco 7550 M3940 2750
10% Colorant #1 0.5 125 3.4
[0066]
9 Fiber Properties Table #4 Colored and Nucleated Fibers 3% 130 C.
Sample Denier Elongation Tenacity Modulus Shrinkage ID (g/9000 m)
(%) (g/den) (g/den) (%) A 129 65.996 4.805 46.823 8.524 B 152.5
41.467 5.555 56.61 9.64 C 154.5 93.919 3.939 36.697 6.595 D 151.1
73.769 3.825 39.584 6.973 E 131 30.29 4.474 46.237 8.678 F 155.4
40.265 3.446 36.636 5.995 G 160.4 28.747 5.044 52.14 8.136 H 153.8
23.227 5.208 52.764 8.893 I 134 23.895 3.94 39.574 8.79 J 151.3
50.934 3.06 32.392 7.019 K 163.4 20.941 5.218 54.94 9.255 L 132.1
37.146 4.768 50.275 8.849 M 159.7 72.707 3.309 34.248 6.976
[0067] Additionally using other commercially available nucleator
compounds a series of yarns were produced using a Basell 35MFI
fiber grade resin, Grade PDC-1302, using the green liquid colorant
(PP Green 5720). In each case 1.2% of the green liquid colorant
were combined with 2500 ppm of Millad 3940 (MDBS), Millad 3988
(DMDBS), HPN-68 and NA-21.
EXAMPLE 4
Polymeric Colorant Fibers with UV Absorbers
[0068] To test the spinnablity of polypropylene fibers with both
the liquid polymeric colorants and a range of UV stablizers, 10
samples using a 10% concentrate of Yellow 485 polymeric colorant
and various UV stabilizers were generated. The 10 samples were spun
under standard sampling conditions as described in Example 2 above.
The table below details the combinations and amounts of UV
stabilizers with two different concentrations of the yellow
colorant from the COLORANT TABLE, above.
10 Fiber Additives Table #4 Colorant UV Stabilizer Sample
Concentration UV Stabilizer Concentration ID (%) (name) (ppm) Y1 2
Tinuvin 783 1000 Y2 1 N/A N/A Y3 1 Tinuvin 783 1000 Y4 1 Tinuvin
783 2000 Y5 1 Tinuvin 783 500 Y6 1 Tinuvin 783 10000 Y7 1 Tinuvin
783 15000 Y8 1 Tinuvin 622 10000 Y9 1 Chimassorb 844 10000 Y10 2
Tinuvin 783 10000
EXAMPLE 5
Textured Polymeric Colorant Fibers
[0069] Yarns containing 1% of the polymeric colorants PP Orange
9802 and PP Violet 9804 were air jet textured. The starting yarns
were 150 denier, 72 filament yarns with standard physical
properties produced in the same manner as those fibers described in
Example #1 above. Two orange yarns were air jet textured with one
violet yam to produce a collaged air jet textured yam.
EXAMPLE 6
Polymeric Colorant Fibers from Liquid Colorant Injection
[0070] For two colors, a second set of filament yarns was produced
by directly injecting the liquid colorant into the feed throat of
the extruder of the fiber spinning equipment. Basell PDC-1302, a 35
MFI HPP, was fed into the extruder at an extrusion temperature of
200.degree. C. The polymeric colors were then injected directly
into the hopper of the extrusion line using a peristaltic pump
(Maguire, Model MPA-6-18). In each case the pump was set to the
lowest possible setting, due to the size of the extrusion line and
the throughput of the melt pump. The two colorants used were 10%
concentrates of the violet and red colorants from the COLORANT
TABLE, above. All yarns were produced under the spinning conditions
described in Table 5 below.
11 Procedural Conditions Table #5 Roll Speed Roll Temperature
(m/min) .degree. C. Feed Roll 500 Not Heated Draw Roll 1 505 55
Draw Roll 2 1000 75 Draw Roll 3(A + B) 1250 120 Relax Roll 1240 Not
Heated
[0071] At these conditions, yarns of different deniers were
produced by adjusting the melt pump speed.
EXAMPLE 7
Polymeric Colorant Monofilament
[0072] Polymeric colorant concentrates were let down into two PP
resins: the first with an MFI of 12-18 g/10 min (Exxon 1154) and
the second with an MFI of 4 g/10 min (Exxon 2252) at a level of 10%
to give 1% colorant in the final polymer fiber. This mixture,
consisting of PP resin and the polymeric colorant additive, was
extruded using a single screw extruder through monofilament
spinnerets with 60 holes. The PP melt throughput was adjusted to
give a final monofilament denier of approximately 520 g/9000 m. The
molten strands of filament were quenched in room temperature water
(about 25.degree. C.), and then transferred by rollers to a battery
of airs knives, which dried the filaments. The filaments, having
been dried, were run across the first of four sets of large rolls,
all rotating at a speed of between 49 and 126 ft/min (dependent on
draw ratio), before entering an oven approximately 14 ft long set
to a temperature of 360.degree. F. After leaving the first oven,
the filaments were transferred to the second set of large rollers
running at a speed of 524 ft/min (dependent on draw ratio) and then
into second oven, set at a temperature of 360.degree. F. The final
two sets of rolls were both set at 630 ft/min and the oven between
them was set at a temperature of 300.degree. F. The individual
monofilament fibers were then traversed to winders where they were
individually wound. These final fibers are thus referred to as the
PP monofilaments. Several monofilament fibers were made in this
manner with the following PP Red 9803, PP Violet 9804, PP Blue
9805, and PP Green 9807.
EXAMPLE 8
Melt Blown Non-woven with Polymeric Colorants
[0073] A colored melt blown non-woven fabric was produced using a
Nordson Fiber systems pilot melt blown system. The equipment
consisted of a 3/4" single screw extruder (24:1) L:D ratio
manufactured by J/M Laboratories--Model DTMB. The airflow was set
to 30 scfin with a max temperature of 625F. The orange colorant
from the COLORANT TABLE, above, in a 10% concentrate, was let down
into Basell 35 MFI fiber grade resin to give a final color loading
of 1% in the melt blown fabric.
EXAMPLE 9
Polyester Polymeric Colorant Fibers from Liquid Color Injection
[0074] A set of experiments similar to Example #6 was conducted
using a low IV (0.62) PET resin. Two liquid polymeric colorants,
PET Yellow 236 and PET Orange 226, available from Milliken &
Company, were used to produce yarn samples. Free fall fiber was
collected from the spinneret, which had the similar vibrant color
as seen with the polypropylene fibers of Example 6.
EXAMPLE 10
BCF Fibers Including Liquid Polymeric Colorants
[0075] Cyan 9806 (from Milliken & Company) polymeric colorant
was used to produce a colored bulk continuous filament (BCF)
textured PP yarn. A three ply BCF 300 denier 72 filament yarn was
produced using standard BCF equipment. Additionally using the
liquid polymeric PP Orange 9802 colorant a single ply BCF 250
denier 72 filament textured yarn was also produced using standard
BCF equipment. The colorant was added to the extrusion line using a
10% concentrate to give a final color level of 1% in the yarns.
[0076] Knitted structures (socks) of the above Examples (except for
Example #8 which was already made into a non-woven fabric) were
then produced.
[0077] There are, of course, many alternative embodiments and
modifications of the present invention which are intended to be
included within the spirit and scope of the following claims.
* * * * *