Note: Descriptions are shown in the official language in which they were submitted.
WO 95133882 ~ ~.I/L~
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DYEABLE POLYOLEFIN COMPOSITIONS AND METHOD
FiPItl of thl Inv.~nti~.n
The present invention relates to an improved dyeable polyolefin ~
and to a process for dyeing fibers and nonwoven materials formed from this
5 c~ ., More pcui ' ~" the invention is directed to a disperse-dyeable fiber
~ , comprising puly~lu~l~, polyester, and a polar material such as
ethylene copolymer. The invention is additionally directed to a ' ' and
process that will allow the use of cationic dyes for polyolefin-based
r- ~ ~ of th~ ~
Polyolefins are 11~.1l,, ' and difficult to dye in that they lack dye sites towhich dye molecules may become attached. One approach to color polyolefin fibershas been to add colored inorganic salts or stable -- ~"~ n-~ 1 jf pigments to polymer
melts prior to fiber spinning. Nonvolatile acids or bases, or materials such as
~UI~ yl~ oxides or metal salts, have been added to polymers prior to fiber
formation to increase the affinity of the fiber for disperse, cationic, acid, or mordant
dyes. Polyolefin fibers may be grafted chemically with ~ . monomers after
fiber formation to improve dyeability. Tex~ile Fibers, Dyes, Finis)les, and Processes:
A Concise Guide, Howard L. Needles, Noyes PUIJIi~lliU.I~, 1986, p. 191.
Efforts to impart acid dyeability to polyolefins, and ~ 'Y PVIY~IUI)JI~
include the use of nitrogen-based polymer additives. For example, im U.S. PatentNo. 3,361,843, various , '', nitrogen-based polymers are added to
polyl,lv~ ,l.c, given a treatment with high, of acidic chemical
reagents, and then dyed in an acid dye bath. According to U.S. Patent No.
3,653,803, dyeing of the POIY~IUIJYI~IIG fiber is somewhat improved by the method
of U.S. Patent No. 3,361,843, but processing of the fiber is difficult due to the
' ' polymer, the dye fastness prvperties not bemg reliably IC~V lul,;bl~, and
tinctorial strengths not being, ~ "~, sufficient. In U.S. Patent Nos. 3,395,198
and 3,653,803, various compatible nitrogen-containing ~,U~VIylll~l~ of ethylene and
.... ..
W0 95/33882 r~ .r '~
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an aminoalkyl acrylate compound are disclosed that, when blended with polyolefins,
render fibers formed from the blend acid dyeable. In U.S. Patent No. 5,017,658, a
fiber finishing agent is used in melt spinning dyeable ~vlyl~lu~ t fibers obtained
by blending a copolymer of an ethylene aminoalkyl acrylate with poly~.u~,yh,l.c.S In U.S. Patent No. 4,557,958, a blend of 70% by weight pvl.y~lv~yl~,..... ,
I VIIIUI~VI~ and 30% by weight ~al~h,.~c ' ~ ' copolymer is applied to a
fabric of woven polyolefin as a coating stripe to prevent fraying of the fabric when
the fabric is cut. In U.S. Patent No. 4,853,290, a blend of ethylene-acrylic acid
copolymer and ~a ~ ' copolymer is coextruded onto a pvl~lu~yl~llc
10 film to serve ar. an adhesive or tie layer to a se~ond polymer.
In U.S. Patent No. 4,782,110, melt processible multiphase ' ,'
are described that can be formed into various shapes by ~ 1 .,.. 7;V
molding, injection molding, blow molding, and extrusion. The ~`" "l"'- ';""
comprises a blend of crystalline polyolefin resin forming the continuous phase of the
c -~ and a cross-linked elastomer of an ethylene alkyl acryhte copolymer
forming the ' ~ phase of a u -" l~ ;- -, The elastomer consists of units
derived from ethylene, an alkyl ester of acrylic acid wherein the alkyl group contains
I to 6 carbon atoms, and a monoalkyl ester of 1,4-' " ~ acid wherein the alkyl
group eontvins I to 6 earbon at~.ms.
U.S. Patent Nos. 3,373,2æ and 3,373,223 diselose polymerie blends
eomprising polyolefin resin, polyamide resin, and either a ~I,v~' ' pvl~.,a~ ,nc,
an e';hylene-aerylie, or a ~ ald.,-yliv aeid eopolymer. Tl-~ --t~. -, polymerie
blends haYe utility in the preparation of films useful in the paekaging industry and in
the ~71~,~dliVI~ of plastie bottles and other eontainers that rec,uire a high degree of
25 ' . ~/'
U.S. Patent No. 3,454,215 discloses a dyeable ~ul,~lu~JI~
eomprising a polyamide and ethylene eopolymer. The . may consist of a
uniform admixture of pvl~t.lu~ , a low molecular weight i , ' unreactive
polyamide, and an additional polymer selected from a group eonsisting of wl ul.yll~
30 of ethylene and an ~ ,.li~7'y unsaturated ester of a saturated fatty acid or a
hydrolyzed produet of sueh cu~ly . U.K. Patent Spo ~ ;r~,~ No. 998,439 also
diselosesa th ~""~pl:~I;r rJ~ eomprisingpvl~ ' andolefmw~,vly
.. . , . . .. ~ .. . . . . . . . . .. . . . . . .. ..
W0 95/33882 P. ~uv 5.'~
~ 3 ~190376
U.S. Patent No. 5,017,658 discloses a dyeable poly~,lu~,yl~l.c c.~
including a copolymer of an aminoalkyl acrylate with p~vly~lu~ , U.S. Patent
No. 4,368,295 discloses a film produced by a melt extrusion process made from
containing an olefin polymer, a linear polyester, and a ~u~.y'
S polyûlefin. U.S. Patent No. 4,174,743 discloses split-fiber, thread, and film products
comprising pvlyulu~/yl~, and ûne or more polyesters and/or pvly
A chapter entitled "Dyeing of r~vlylJ~ulJ.r1~.1~ Fibers" in ru~ .C Fibers,
Science and Technolov~y by Mike Ahmed provides a cù.~ h.,.,~ study of the
techmology invûlved in dyeing ~vly~Jlu~ h,l,~ fibers in the mid 1950s to the 1980s.
Sectiûn IV.I regarding mordant-dyeable fibers discusses problems relating to light
fastness, wash fastness, and crock fastness of certain dyes. The study concludes that
the fastness properties of disperse-dyeable polyl,lu~.yl.,ll~ fibers are generally
r to the textile trade.
An article entitled "Surface Dyeable Modified PP BCF Yarns" in
f 7 ~ /TPrn~ -- ' ; ~e, Vol. 41/93, October 1991 discusses adding a modifier
to PP BCF yarn. A brochure entitled Polymer ~ - ' v by Eastman Chemical
Products, Inc. discusses Epolene E-43 wax as a ~, ' for
nylon/~ulyylu~yl~ , Anarticlesentitled "M~ g;-,.1 andr~ ~ '
Prûperties ûf Extruded rvly~,.u~yl,~ /Nylon-6 Blends" by Wan Gheluwe et al.
20 discusses nylûn and ~vly~lulljl~,~, blends using Zytel 211 as a ~ . ' ' . An
article entitled "New Functional Materials for Absorbent Products" by Dr. Suzuki in
The New Nonwoven World, Fall 1993 discusses new ~uly~lu~lv,,~ materials for
absorbent products.
In an article entitled "Polymer r' .' ' _y ûn the Dyeing Propefies ûf
Synthetic Fibers," Keith Sillcstûne reviews some ûf the prior art effûrts conducted
with regard to proposing , ' ' O ' changes in the fiber production for marginal
dye uptakes in pclylJlu~y~ . Other relevant articles are "Dyeing Synthetic Fibers,l'
H.E. Schroeder, C&EN, Sept. 10, 1956; "Dyes for Hydl~ Fibers," H.E.
Schroeder et al., Textile Researc~7 Journal, Vol. 28, April 1957; and "The Influence
of Polymer ~vl~ y on the Dyeing Properties of Synthetic Fibers," Keith
Silkstone, Rev. Prog. Coloration, Vol. 12, 1982.
wo 95l33882 r~.,~.. .v
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The need exists for improved polyolefin ~ u~:~;..,.c and materials that will
be ~U~ Ily dyeable with a broad range of dyes. A particular need exists for
~ulylJIu~ l., based ~ -u~ that can be used to I~ h~ fibers that are
spinnable and may be formed into fabric sheets including nonwoven fibers.
5 S~ y of the Invention
According to the present invention, there are provided novel, , and
articles of polyolefins that are more dyeable, novel methods of dyeing polyolefin
articles, amd novel shaped dyed articles, including novel dyed PUIYIJIU~YI~IIC; fibers,
produced by such processes.
A novel polyolefin fiber comprises about 99% to gS% by weight of a
polyolefin and a selected amount of an ethylene copolymer comprising about 70 to82 % by weight ethylene amd about 30 to 18 ~v by weight of an alkyl acrylate wherein
the alkyl has I to 4 carbon atoms, said ~ containing 0.2 to 3.0% alkyl
acrylate by weight the sum of the poly~lu~,yl~.l,, amd ethylene copolymer, whereim at
15 least a portion of said copolymer is grafted onto said polyolefin and an effective
amount of a disperse dye diffused into the pulyl~lu~ to produce a colored fiber.A IlJIIU~ modifier may be included that comprises a ll~ùlloOly~,~id~ and a long
chain l~dlU~UbUII with a hydrophilic group.
A novel process for formmg ~JulylJIu~ .c based fibers comprises (a)
20 combining pulyl~lu~L,..., with a selected amoumt of an ethylene copolymer of about
70 to 82% by weight ethylene and about 30 to 18% by weight of am ethylene alkyl
acrylate wherein the alkyl group has 1 to 4 carbon atoms to form a ~ (b)
extruding the ~,u..~l~u~ into fibers; and (c) exposing the fibers to a selected
disperse dye bath containing a disperse dye, either for dyeing or printing
A novel polyolefin fiber comprises about 99 to 70% by weight pulyylu~
a fiber grade polyester of from about 0.1 to 15% by weight; a selected amount of a
polar group material, such as an ethylene copolymer, a maleic anhydride, or an
acrylic acid; and a hydrophilic modifier comprising a o~ and a salt of a
linear aLkyl. The polyester may be , ' ' with the ~IY~JIU~IUII~ JUI~U group
material/hydrophilic modifier matrix. The ethylene copolymer may comprise about
70 to 82% by weight ethylene and about 30 to 18% by weight of am alkyl acrylate,
.. , . , , . , ,, . ,, ., . ... ., . , ... . ,,, . . .,,,, .. . ,, ,, .. , ,, , . , . = .. ., . = = . . ,, . ,
, _
WO 95133882 P~,l/U.,,~'C
5 : ~ 1 9 0 3 7 6
wherein the alkyl has I to 4 carbon atoms, said alkyl acrylate present in an amount
of 0.2 to 3.0% by weight. The hydrophilic modifier may comprise a fused
,.... of a ~ and a linear alkyl phosphate and provides additional
c~mr ~l'hili7:~tif n of the PUIYIJIU~ and polyester. This modifier may be present
in an amount of from 0.1 to 2% by weight, and preferably between 0.4 and 1.0% byweight, the sum of the puly~JIu~ , polyester and ethylene copolymer.
A novel process for dyeing shaped articles based on a polyolefin comprises (a)
forming into a fiber a <~ of about 99 to 70% by weight of a polyolefin and
a selected amount of an ethylene copolymer comprising about 70 to 82 % by weightethylene and about 30 to 18% by weight of an alkyl acrylate wherein the alkyl has
one to four carbon atoms; and (b) exposing the fiber to a disperse dye.
A novel process for dyeing fibers based on PC~IYIJIU~JJI~I~C comprises (a)
combining l~uly~lu~Jyk,l~ with a selected amount of an ethylene copolymer of about
70 to 82% by weight ethylene and about 30 to 18% by weight of an ethylene alkyl
acrylate wherein the alkyl group has ûne to four carbon atoms, to form a
. (b) extruding the C~ into fibers; and (c) exposing the fibers to
a seiected dye bath.
A novel process for forming fibers based on puly~Jlu~Jyl~, comprises
combining isotactic pulylJIu~Jjlu~ polyester, a polar group material, and a selected
llydl, r~ li-` modifier. The polar group material may be ethylene copolymer of about
70 to 82% by weight ethylene and about 30 to 18% by weight of an ethylene alkyl
acrylate wherein the alkyl group has I to 4 carbon atoms. Alternatively, the polar
group material may be a maleic anhydride or an acrylic acid. The I~YdI~
modifier may be present in an amount between 0.1 and 2.0% by weight, and
preferably between 0.4 and 1.0% by weight, the sum of the ~uly,ulu~du~lc ~ polyester,
and ethylene copolymer. The polyester or c~l uly~ thus has excellent
crlmp~ ~lhility to the modified PUIYIJIU~ ,. Polyester may be i Y.I ~ at a very
minute level of about 0.1% by weight up to about 15% by weight. To obtain an
acceptable level of dyeability with a high exhaust level and subsecluent high light
fastness, a desired level of polyester may be between I to 10% by weight, with an
optimum level at about 3 % by weight.
wo 95~33882 P~~
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The disperse dye allows for the cost-effective production of fibers that
preferably have good light fastness and, in at least some instances, good wash
fastness, and good crocking (bleeding) properties. Generally, the dye will have a
w~ J~aLIv.,ly high mass to polarity ratio and will be only slightly polar. The rate
5 of dyeing is inversely ~lU~JUlLiU~I to the mass of the dye and directly ~IU~UILiU~
to the linearity and absence of bulky side chains. A dye baving low solubility in
water and high solubility in fiber is preferred. Dyes generally intended for dyeing
acetate fibers or polyester fibers are likely candidates. An open amorphous fiber
structure is also preferred. Based on the work that was conducted on several standard
10 dyes, this unique . , exhibits 1" ~ I, exhaust ~ with an
acceptable level of light/wash fastness and crock .1 - ,.. i. .;~1;. ~
The polyolefin in these f~J"'~ "` and processes preferably is isotactic
~IylJIu~ ,. In the processes, the ~ . may be a blend or one in which at
least a portion of the ethylene copolymer is grafted onto said polyolefin. The
1~ ethylene copolymer in the ~ . include ethylene methyl acrylate, ethylene
ethyl acrylate, and ethylene butyl acrylate.
It is an object of the present invention to provide an improved inert
;Iydl~,' ' - polyolefin-containing, . with desired dyeability and wettability
, 1. . ~. 1 . ;~1;. ~ It is a further object of the present invention to provide an improved
20 polyolefin-containing web comprised of fibers, or a nonwoven or fibrillated film
suitable as cover stock for various sanitary products. Still another object is to obtain
and retain high l~ydlu~Jllili~,;~y and liquid strike-through properties in a strong, well-
bonded, nonwoven llydl~.' ' ~ material, including cûntinuous and/or staple fibers
utilizing polyolefin,
2~ It is a significant feature of this invention that the poly~lu~l~
material may be used to form fibers having ~ ; - - for either woven materials
or nonwoven materials, and that the fibers are spinnable at, Ily acceptable
rates. Yet another feature of the invention is that a PUIYIJIU~YI~ based material may
be efficiently modified to form a material having a wettability contact angle of less
30 than about 80.
An advamtage of the invention is that the wettable polyolefin material
according to this invention is more easily dyeable than prior art polyolefin flber
... . .. = .... ... .... ... ~ _ .. .. . .... .. . = ... .... _ . . _ ... .. . ..... .. . = .... . _ .. ... _ .
WO gS~33882 ~ .,, '.'C ;' .
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materials. These and further objects, features, and advantzges of the present
invention will become apparent from the following detailed .h-~. rirtir,n
.
~,ot .ilf.A De~ ptirm of the Invention
Polyolefins usable in accordance with this process are crystallme POIJ~tl~YI~
5 POIY~JIU~YI~ or w~ly thereof having melt indices in the range of from about
0.1 to about 80 g/10 min. The most important polyolefin for use in formation of
fibers at this time is isotactic ~Iy~lu~ylul.., which is commercially available from.
many sources. The ~uly~ h,l.., can contain the usual thermal, oxidative, and
ultraviolet light stabilizers.
The fiber-forming ~- . may comprise pulylJIulJjh.llc and a copolymer
of ethylene and am alkyl acrylate having 2 to 30% by weight, suitably 2 to 15%,
preferably 4 to 10%, most preferably about 7%. In accordance with this invention,
the copolymer of ethylene and an alkyl acrylate may be grafted onto the
poly~lv~l~ .. The ~ù ~ may alternatively include a blended
15 polJ~,.u~ylull~lcopolymer mixture, or both grafted and blended ethylene alkyl acrylate
copolymer. An advantage of the ethylene alkyl acrylate copolymer is that it is both
1~ "",pl~ amd compatible with ~uly~lu~ c so that processing difficulties are
mir~imized or prevented. By the term n~ , ''-1 ~ is me~nt that the copolymer does
not separate into discrete particles in the l~uly~lu~Jjl~..l-, I , that are
20 observable under an optical Ill;.,lU~W~JG at a ~ ~ of times 250-500. The
grafted version of ~ulylJlu~l~l.., offers an excellent bridge for optionally adhering
with the polyester or ~u~ul,~
Tbe ethylene copolymer comprising ethylene and an alkyl acrylate m the
used in this invention include ethylene methyl acrylate, ethylene ethyl
25 acrylate, and ethylene butyl acrylate. Ethylene methyl acrylate copolymer ("EMA~)
alone or in blends has been used in film, extrusion coating, sheet, molding, tubing,
profile extrusion, and WCAIII ' areas. Compared to low density poly.,ll-y
IIUIIIULIUIYI~ h has a lower softening ~ r~ (138F), a reduced flexural
modulus, and improved c..v;.~ ' stress crack resistance. Ethylene copolymer
30 has been disclosed for use as a blending component with low density PUIJ~ YI~,.I."
p~ly~lu~jlu.l~, polyester, and puly~ul. ' to improve impact strength and
W095/33882 l~ l/u.,,~A i~ .
S ~ 8~ 9~376
toughness, increase heat seal response and promote adhesion, reduce stiffness, and
increase the surface coefficient of friction. Modern Plastics, Mid-October
~n~,lu~d;~ Issue, 1991, pp. 71-72.
Ethylene ethyl acrylate copolymer ("EEA") resins are tough, flexible
5 w~uly~ that have found application in hoses and tubings, gasketing, disposablegloves, and balloons. EEA has also been used for hot melt adhesives.
As the ~ yl~ly' content of EEA increases, the copolymers become more flexible,
tougher, and more resilient. The polarity of high i Lll.~ y' resins may enhance
surface acceptance of inks and provide adhesive properties. Ethylene butyl acrylate
10 (~EBA~) is usc-d for low melt-index films. It produces a tough film at low
W and is employed mainly in the packaging of frozen fûods.
P~uLi~,ul~uly preferred cu~ulyll.~ are the ethylene methyl acrylate random
W~UIy~ of ethylene and ' yl~l~l~L~ and the ethylene ethyl acrylate random
cul,oly of ethyleneand eL'I..~ ' The EMA cu~ preferably contain
about 20 to 24%, and preferably about 20%, by weight ~ LhJI~.~- The EEA
w~ùl~ preferably contain about l 5 to 3o % by weight of the cL~ l y moiety.
These ~puly have a melt index of 1 to 20, preferably about 18, and have a
thermal stability such that when the i I ~; is raised at 10C/min., under flowing
rlitrogen, less than 0.75% of the copolymer weight is lost at 300C.
It is a critical feature of the present invention that the amount of alkyl acrylahe
in the ~ul~ u~yl~ ., ethylene alkyl acrylate copolymer be present in an amount
between 0.2 to 3.0% by weight, and preferably between 0.5 and 2.4% by weight, inorder to produce a textile fiber having ~ "~, acceptable processing
~ a --r. h ,;~ If the amount of alkyl acrylahe component is increased above 3.0%,
a textile fiber produced therefrom loses its necessary ~tl,~lJIU~ .llC ~ a ~
degrades during high-speed ~Iber processing, and produces a final fiber with
"y low henacity (less than about 1.5 g/denier) and excessive elongation and
with significantly different melt . l, .- ~ to be ~ For
example, carpet made from fibers having an alkyl acrylahe component between 3.0
and 5.0% melts excessively upon exposure to flame as compared to wll~lLiul-al
~ulyL~ulJyh,l~c carpet to the point that it ' "y fails a standard "pill test" for
flame resistance while standard ~IY~JIU~JYI~ passes. Further, at an alkyl acrylate
. _ . _ . . .. . . . . . . .. . . . .. . . . ... .. . .
WO 95133882 r~
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content above 2.4%, the fiber fuses together on the heated drawing rolls and is
basically A 1- on modern, .,;~li sca'ie e1uipment. These subtie, yet
commercia'ily critiea'i, limitations were complete ~ , X '
An a'ikyl acrylate component of less t~ian 0.2% produces a fiber with
5 . rr poiarity ~,rul character to impart a desired dyeability to aeeept a
desired even, deep color. Aeeordingly, the maximum amount of alkyl acrylate
component is preferred, subject to aceeptable fiber production and i~ '
ch iraeter. The more preferred alkyl acr~vlate component is between 0.5 to 2.4% by
weight for l~ul~i~lui~yh,l~, . which do not include polyester, with 1.0 to
10 1.5%beingmostpreferredfori?uly~ u~ ,/polyester~ . r~ ului~yl~
without the grafting proeess does not form continuous or bulk-eontinuous filaments
with polyester or w~oly~l. The degree of çnmp~tihili7~tinn to enhanee the
processibility can be augmented by . _ the hydrophilic modifier, sueh as
a illu~lu~ly~lidc and a long chain l,~Jlu~il,ull with a hydrophiiic group.
It is understood thiat polymer additives, sueh as thermai, ûxidative, and
ultraviolet light stabili_ers, whieh are typiealily found in fiber-forming polymer
i, may be added without departing form the present invention. The
percent by weight va'iues given in this application are expressed as a pereent by
weight of the . whieh ineludes a polyolefm, sueh as polyi~luiu~ " and
20 a polar materiali, sueh as an alikyl aerylate eopolymer, and preferably both a
l~y~lilulJh;lic modifier and polyester. The percent valiues stated for these materia'is
should thus uniformly eombine to 100%. Other additives may be mcluded to diliutethe polyolefin ~ . If sueh additives are ineluded in the, . the
ratio of polyolefin to polar materia'i would remain eonstant, and the tota'i pereent
25 valiues of all materialis, meluding additives, would then exeeed 100%. For example,
if nylon were used in the . wmeh did not include polyester, the pereent
valiues of the ~ul~i~lu~ , eopolymer and hydrophilic modifier would not ehamge,
and would stilil totali 100%.
The ethylene cu~vly utiiized in the present invention eontain at least 70%
30 ethylene, with ti~ie alkyl aery'iate eomponent present between 2 to 30%, typiealily
between 10 to 24%, depending upon the seleeted alikyl acrylate. Depending upon
the amount of alkyl acryliate eomponent present in the ethylene eopolymer, the ratio
WO95/33882 r l,l r
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of ethylene copolymer to polyl~lu~ can be easily adjusted to maintain the properamount of alkyl acrylate in the final product. It is also important that the amount of
ethylene contributed by the ethylene copolymer be maintained below 10%.
Accordingly, it is preferred that the higher the percentage ûf alkyl acrylate in the
5 copolymer, the easier it is to obtain the proper balance Of ~ r ' By way of
example, a mixture of 93% ~1~ , and 7% ethylene methyl acrylate having
a 20% methyl acrylate component produces a ~ u~JJ l.,~l.,lethylene methyl acrylate
copolymer ., having a methyl acrylate component of about 1.4%~
Similarly, a 3% addition of the same ethylene methyl acrylate copolymer produces10 a methyl acrylate component of 0.6%.
The invention can be further understood by referring to the following
examples in which parts and ~~ Lv~ are by weight unless otherwise indicated.
am~le 1
A ~ yl~ll., alloy ~ , containing 90% by weight of a commercial
15 fiber grade of isotactic pol~,lu~ having a melt flow rate of 18 (ASTM
D-1238-89, 230C, 2.16 Ibs) and containing thermal, oxidative and ultraviolet light
stabilizers and 10% by weight of a copolymer of ethylene Ill.,lil~ ,l y' is prepared
by first dry mixing the polymers and then melt blending the mix in a 40 mm Berstorff
extruder at 246C. The ethylene copolymer contains 24% by weight of the
20 Ill~ ;~lJ' cr , amd has a melt index of 18 (ASTM D-1238-89, 190C,
2.16 Ibs). The resulting l- v compatible polymer blend is cut into nibs
after water~uenching, which are then fed to a melt spinning apparatus and 50-60
denier per filament fiber is spun at 230-245C. A mineral-oil based finish containimg
anionic surfactants is applied to the fiber bundle after spinning, but before drawing.
25 The fibers are drawn times three to give a final denier of 18-20 per filament.
Specimens of the fibers are knitted on a knitting machine to produce a tubular knit
fabric. Samples of the fabric are dyed according to the procedure given below.
Dye procedure steps involving a scour, dye, and reduction clearing operation
were used, as explained hereafter. In the scour step, the sample was rinsed im cold
30 water for 5 minutes and the bath changed. The sample was introduced in a new bath
of 0.5 g/l Keirlon TX-I99 wetting agenVdetergent and 0.25 g/l of soda ash, ~en
wo ssl33ss2 r~"u....
~ 2 ~ 9 03 76
heated to loOF and held for 10 minutes. After cooling to 100F, the sample was
rinsed.
Ill the dye step, the dye bath was prepared as follows: 1% dye, 1% Triton
X-100 (surfactant), 1% Synthrapal LFP (disperse leveling agent). The pH was
S brought to 5.5 with acetic acid and the bath heated to 120C at 2.5C per minute.
The bath was held at that t~v...~ c for 30 minutes, then cooled to 40C at 3C per
minute. The sample was rinsed warm, extracted, amd dried. Optionally, for good
fastness properties an additional step, namely, reductive clearing/stripping, may be
carried out as follows.
In the reduction clearing step, wash dyed samples are placed in a series of
tanks: first tank, wet out with Triton X-100; second, third, and fourth tanks,
reductive clearing at 70C with 8 g/l of sodium hydroxide at 32% 4
g/l sodium 1~ for a total of 30 seconds. Rinse occurs in the fifth tank, and
the sample is neutralized with acetic acid in the sixth t~nk. This process of reductive
clearing ensures the removal of surface adhered dyes and in general produces better
fastness results.
A ~ graft . containing 90% by weight of a commercial
fiber grade of isotactic y~ JIv~;lc..~, having a melt flow rate of 4 (ASTM
20 D-1238-89, 230C, 2.16 Ibs) and 10% by weight of a grafted copolymer of ethylene
1ll~,~1~l.~' (and containing thermal, oxidative amd ultraviolet light stabilizers) is
prepared by first dry mixing the polymers and then melt blending the mix in a 40 mm
Berstorff extruder at 246C in the presence of sufficient free radical initiatorperoxide, specifically, 2,5-dimethyl-2,5-di(tertiary-butyl ~ r) ~, to visbreak
25 the . , to a product melt flow rate of 18. The ethylene copolymer contains
24% by weight of the - ~ ,Iy' -~ ~~ , and has a melt index of 18 (ASTM
D- 1238-89, 190C, 2.16 Ibs). The resulting l~ , compatible polymer blend
is cut into riibs after water-quenching, which are then fed to a melt spinning apparatus
and 50-60 denier per filament fiber is spun at 230 - 245C. A mineral-oil based
30 finish containing anionic surfact~mts is applied to the fiber bundle after spinning, but
before drawing. The fibers are drawn times three to give a final denier of 18-20 per
WO 95133882 P~
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filament. Specimens of the fibers are knitted on a knitting machine to produce atubular knit fabric. Samples of the fabric are dyed according to the procedure given
irl Example 1.
xample 3
S A ~ly~lu~Jyk,llc graft ~ - containing 90% by weight of a ~ .,;al
fiber grade of isotactic ~UIy~llU~yl~ C having a melt flow rate of 4 (ASTM
D-1238-89, 230C, 2.16 lbs) (and containing thermal, oxidative and ultraviolet light
stabilizers) and 10% by weight of an alloyed and grafted copolymer of ethylene
L~Iy' is prepared by first dry mixing the polymers and then melt blendirlg
the mix in a 40 mm Berstorff extruder at 246C in the presence of sufficient free
radical initiator peroxide, specifically 2,5-dimethyl-2,5-di(tertiary-butyl
.u~y, , to visbreak the ~ . to a product melt flow rate of 35. The
ethylene copolymer corltains 24% by weight of the ' yl~ly' , , and
has a melt index of 18 (ASTM D-1238-89, 190C, 2.16 Ibs). The resulting
l ~ ~, compatible polymer blend is cut into ribs after water-quenching, which
are then fed to a melt spinning apparatus and 4 denier per filament fiber spun in a
partially oriented yard (poy) operation at a take-up speed of 3,000 rpm, and
. '~, false twist textured to 2.0 to 2.5 dpf fibers. Specimens of the fibers are
knitted on a knitting machine to produce a tubular knit fabric.
A series of samples of polymer made as described in Examples 2 & 3 and
were evaluated with a series of disperse dyes according to the dye procedure of
Example 1. The results are set forth in Table I. No ~yl,l~;d,lc difference was
detected with respect to dyeing ~ bet veen Example 2 and Example 3
samples. Table I lists dyes that are suitable for dyeing fibers according to the present
irlvention. Light fastness, and crock fastness tests were also performed on yarns at
2-20 deniers per filament.
W0 9S133882 I'~ . ''C
r, ~ ~ r t -13- 2 1 9 ~ 3 7 6
TABLE I
DYE E~XHAUSTION
- Dye Exhaustion
;...- "t -~ Dye Type Light Xenon Crock Fastness Exhaust/
5Disperse Dyes AATCC 16E, AATCC 8-1985 Yield
at 1% ` 40 hours
Dry Wet
Disperse Blue 361 4
Disperse Violet 28 4-5 3-4
Disperse Blue 77 3-4
10Disperse Yellow 23 5 5 5 4 5
Disperse Yellow 54 4 5 5 4
Disperse Yellow 86 4 4-5 4-s 4
Disperse Yellow 232 1 4-5 4-5 3-4
Disperse Yellow 3 5 5 5 3-4
15Disperse Blue 35 4 4-5 4-5 3 4
Disperse Blue 87 4 5 5 4
Disperse Blue 291 3-4 5 5 4-5
Disperse Blue 354 1 4 4 4-5
Disperse Blue 60 5 3-4 3-4 4
20Disperse Blue 118 4-5 4-5 4-s 3-4
Disperse Blue 183 1 5
Disperse Red 60 4-5 3-4 3-4 4-5
Disperse Yellow 64 5 4 5
Disperse Red 167 3-4 4-5 4-5 3-4
25Disperse Red 73 1 4 4 4
Dis,oerse Red 127 3 3-4
Intrawhite FWA 4-5 5 5 4-5
Disperse Green 9 1 4-5 4-5 4-5
Disperse Blue 79 1 4 4 3-4
.. . . . . . .
WO 95133882 P v I / ~J .. _ .'^ . v
-14- ~ I q 03 7 6
FASTN~^55 RATING l~XHAUST RATING:
5 - No Change 5 - Total Exhaust
4 - Slight Change 4 - Govd ~xhaust
3 - Noticeable Change 3 - Moderate Exhaust
2 - Significant Change 2 - Poor E~xhaust
1- Severe Change 1- Light Staining
Dye exhaust or the extent to which the textile depletes a dye bath has been
primarily used as the basis for :' v the dyeability of the polyolefin. Other
~ ( properties, such as light fastness, wash fastness, and crock fastness, are
more a function of many other variables, such as the conditions of dyeing, the
auxiliaries used in dyeing, and, in general, the dye procedure and the after-treatment.
Consistent with the Gray Scale Grading System devised by the AATCC, a
scale of I to 5 is used, with 5 being a near total exhaustion of the dyestuff from the
dye bath to the substrate and 1 being merely a staining of the substrate, almost all
dyestuff remaining in the bath. All other grades between 5 and 1, including the
illt l, ' such as 3-4, are based upon a linear scale of dye exhaust from the bath
to the substrate. While a rating of 5 would be the most preferred, for operational
purposes a rating of 3-4 or above is acceptable as a standard for a polymer fiber to
be considered "dyeabler with a particular dye.
Those skilled in the art will appreciate that in most
the disperse dyestuff will be a mixture of one or more selected dyes. The
,~ of the selected disperse dye or dyes should be at least 0.1% to obtain
the significant benefits of the invention. There is a current trend for blends of dyes
to be used which optimize different ~ of specific dyes for maximum
25 ~ r^~ Carpets made from disperse dyed fibers from this polymer exhibited
excellent resistance to bleaching. In a ble~ch test it was found a typical 10% solution
did not produce a change in color, whereas a 100% solution produced only a
significant to modeMte change in color.
Carpet samples made from the subject polymer and disperse dye are stain
resistance as per the carpet industry's standard Kool-Aid test. On a scale of I to 10,
the samples scored an absolute 10, indicating no stain on tested samples. Generally
_ . _ _ , .. . . . . ... .. . . _ . . .. . _ _ _ . .
wo s~l33ss2 r~
'', ;~''t~ 15- ~l ~0376
speaking, dye results indicate that the grafted version of the present invention taught
in Example 2 and Example 3 show a slightly better ~ ru -- than tbe blended
copolymer version of Example 1.
The present invention is ~uliuul~ly useful with fibers, and fibers of various
5 deniers can be adequately wetted both in the form of fibers or nonwoven webs made
from tbese fibers. Round or lobed fibers are for apparel, upholstery, and carpet face
yarn uses and can have a denier of about I to 60 without ~ dyeing
problems by the present technique. These fibers can also be used in production of
other articles, such as decorated ribbons or nonwoven textiles. The tape fibers are
- 10 generally used for caTpet backing and are of heavier denier, i.e., about 500 to 1500
denier. Fibrillated film fibers are used to cordage carpet face yarn or upholstery.
For fibers to be fully penetrated by dye, tbe spinning and dra ving processes
should be conducted in a manner to produce a fiber with a uniforln structure through
its cross-section, i.e., minimal sheath/core structural differences. On the other hand,
15 greater economy of dye used in dyeable ca pet backing made from woven tapes can
be obtained if such tapes do possess a sheaWcore structure. In these sheath/corestructures, the sheath is dyeable, while the core exhibits very little dye pick-up.
Tbus, less dye is used to dye a backing that is made up from such fibers.
After spinning of the fibers, but before drawing, a spin finish c~m be applied
20 to the fibers. If such a material is used, it may be anionic, but preferably is nonionic
in nature. Nonionic spin finishes are ~ lly available, and a preferred one is
Dispersol VL. Suitably usable is Nopcostat 2152P~ which is thought to be a modified
coconut fatty acid ester. Finishes cont~ining mineral oil act as a plasticizer and can
imcrease dye uptake rate at the fiber surface. A water-dispersible or water-soluble
25 finish such as Dispersol VL is preferred. Finishing operations can optionally be
performed on the fibers before dyeing. For example, the fibers can be texturized by
'Iy crimping or forming, such as described in Te~aile Fibers, Dyes,
Ffnishes, and Processes: A Concise Guide, Howard L. Needles, Noyes ru
1986, pp. 17-20.
30 It has been found desirable in some ~ to blend a polyamide, such
as nylon 6 or nylon 6,6, imto a first ~ , (a ~uly~ yl~ and ethylene
copolymer , ) to further enhance the first . . without sacrificimg
.
WO 95/33882 1 ~
._ t. ~ 16- 2 1 ~9 ~ 3 7 6
the desired spinning or dyeing properties of the fiber. The addition of polyamide
forms a second CJ~ (e.g-, a ~IY~IU~ U~ IUI~ 6 ~I." ~
vith improved n ~ y~ improved tenacity and improved resiliency compared to
the first ~ ,u~ , even to a point that the modified fiber is more resilient thanS l~uly~Jlu~Jyl~.l., alone. The added polyamide is by weight about 1 to 20%, andpreferably 5 to 15%, the weight of the first ~ ;--, When a nylon component
is added, the ethylene copolymer may be reduced provided that the alkyl acrylatecomponent does not drop below an amount sufficient to keep the otherwise immiscible
pol~lu~ and polyamide from separating (usually about 0.5% by weight). A
10 preferred .-.~ .,- l;-- is about 1.4% alkyl acrylate component (~ 7%
ethylene copolymer) and 15% nylon 6, with the remainder (d~lu~.ill~t~ly 93%)
P~IY~IU~JYI~C. For this one preferred ~ u- Ii--" the r' ''~,ly expressed phr
values are 100 phr ~ulyl~lulJyl~,llc, 7.5 phr ethylene copolymer, and 16.1 phr nylon.
In using a c~ of the ~IY~JIU~Y~ and ethylene alkyl acrylate
15 cûpolymer (and optiûnally vith poly. /~u~ . and/or l.~JIulJl.il;~ modifier),
it is important that the pulyl~u~yl~ and ethylene alkyl acrylate copolymer be
uniformly i..~.~ ' prior to forming the . 1, into a shaped article. The
may be only a uniform blend, but preferably, and in accordance with this
invention, it is a ~ , in which at least a portion of the ethylene alkyl acrylate
20 is grafted onto the puly,ulu~ ,. Blending and/or grafting can be - ,' ' ' in
a separate step prior to forming, or the blending and/or grafting and extrusion can be
carried out in the same operation if the extruder has a suitable mixing section. Poor
blending and/or grafting can result in uneven dyeing even if the remaining steps of
dyeing procedure are properly conducted.
l~e grafting of ethylene alkyl acrylate cûpolymer to polyolefin polymer,
preferably isotactic polyl/~ul~yl~,n~, for use in this invention is ~ ~ ~ by
subjecting the ethylene alkyl acrylate copolymer to co-graft IJul~, in the
presence of the polyolefin polymer. The graft l!uly ' " method is not critical
and the graft pul~..-.,.i~iu.. can be effected according to cu..~, ' methods
30 employing organic free radical initiators. The pc ly conditions may be those
known to the art. The organic ' ~O ,, agent used in this invention
imcludes:
W095133fl~2 p~,""~,~
F~ 17- 2190376
2,5-dimethyl-2,5-di(t-L 'yly. .uAy)hexene-3,
2,5-dimethyl-2,5-di(t-' _ YIY~IUAY`'
1,3-bis(t-'_'.~ ~.uAy;~uyluy.~l)benzene~
2~2-bis(t-hULyly~,~UAy)-p~ Uy
- S dicumyl peroxide,
di-t-butyl peroxide,t-butyl benzoate,
l,l-bis(t ~ Iy. .UAy)-3,3,5-~ yl '
2,4-di~ lul~llLu~l peroxide,
benzoyl peroxide,
10 yl, 1P, and the like.
Preferred are:
2,5-dimethyl-2,5-di(t-1, ~YIY~IUAY)~ 3,
1,3-bis(t-t '~ly.~uA~i~uyluyyl)benzene~ and
2,2-bis(t-L. ~/ly~luAy)-p~lii~uylu~ .,llLI,..~ .
The Ih ~ ~y~ resin . of this invention can be obtained by
addmg 0.01 to 0.3 parts by weight, preferably O.OS to 0.2 parts by weight, ûf amorganic ~li~l ,, ~ agent to 100 parts by weight of a mixture consisting of 99
to 85% by weight, preferably 96 to 90% by weight, of yulyyluyyl~ , and 2 to 13%
by weight, preferably 4 to 10% by weight, of an ethylene alkyl acrylate copolymer,
20 and then subjecting the resulting mixture to therm~l trPatment in a mixer (e.g., a
Banbury mixer, a kneader) or an extruder at 170 to 300C, preferably 180 to
250C, for 0.2 to 30 mimutes, preferably O.S to 20 minutes. Fiber grade polyester
may ~. . 'y be introduced up to 15% by weight, preferably about 3 to 5% by
weight, of the entire matrix, in which case the y~lyylu,ujlul~ percent would be
25 decreaæd by the weight percent ûf added polyester.
When polyester is not I ' into the matrix, the ~ compriæs
about 99 to 85% by weight polyolefin, preferably yulyyluyyl~,ll., and about I to 13%
by weight the polar group material, preferably ~MA. The alkyl acrylate in the
is about 3% by weight or less, and the maximum amount of ethylene is
30 about 10% by weight. If a hydrophilic modifier as discusæd above is utilized in the
it has a maximum ~ ' of 2% by weight to the overall matrix.
WO 95/33882 1 ~
~ \ S d ~ 18- 2 ~ 9 ~3 7 6
When polyester is ~ into the c,~mr-irir.n the amount of polar
group material and hydrophilic modifier need not change. The added 0.1 to 15 % by
weight polyester to the total . . will thus decrease the range of polyolefin
to about 99 to 70% by weight. In the matrix of only polyolefin and polyester, the
S polyolefin comprises from 99.9 to 82% by weight, and the polyester comprises 0.1
to 18% by weight. Maleic anhydride or acrylic acid may be substituted for EMA asthe polar group material when polyester is included in the . although the
weight percent of these altemative and less preferred polar materials will be less than
the weight percent of EMA.
One ~ u ~ of this invention deals with the synergistic I ' among
puly~v~lu.._, polyester or copolyester, ethylene methyl acrylate (or maleic
anhydride or acrylic acid), and preferably a hydrophilic modifier comprising a
'y~.iJ~ amd a salt of a linear alkyl. Polyolefin-type polymers are the most
~h~ fibers to wet using Wll~ iUllal fiber production techniques.
15 ruly~JIu~ ,.l., practically is a nonpolar polyolefin polymer with a very low surface
energy. It has been reported that the surface energy of poly~.-u~ is a 28.7
dynes/cm with 26.0 and 2.7 dyneslcm dispersive and polar fractions, I~ ,_ly.
r~ly~lu~JJI~,~.., can be nnodified with EMA at a certain level to enable the
polyolefin fibers to be reliably dyed with disperse dyes. However, the udu~,liu
20 of polar groups does not impart any "wettable" or ~dyeable" ~
Similarly, both acrylic acid and maleic anhydride modified products also do not yield
a wettable polymer or fiber. C .,;~1 materials, such as the Polybondn' material
from Uniroyal Chemical Company, Inc., combine functional monomers such as
acrylic acid or maleic anhydride with polyolefin, and thereby fomm chemically grafted
2S polyolefin cu~ul~ . This chemically grafted polyolefin copolymer, when
combined with POIY~JIU~ " similarly does not produce a wettable fiber.
When a preferred hydrophilic modifier such as disclosed herein is used in
with polar substra~es, such as EMA or Polybondn', the wettability of the
polyolefin improves dramatiGllly, as measured by contact angle. In some
30 Al,J,l;.-l;....~ this increased wettability is beneficial to obtaining desired dyeability
WO 95J33882 , ~, ,,,1~ ~( -
. " ` ' ~ S
9- 2 1 9 0 3 7 6
A preferred modifier is a r~ ., of nonionic and anionic structures. The
nonionic structure may be a o~ c with a melting roint of a~ 'y
66C and a boiling point of ,~ ly 260C. Glycerol ("GMS")
is the presently preferred o~ idc. This nonionic structure is highly distilled,
- 5 with a ~'~ id~ content in excess of 95% by weight. In some ~ a
"'~,~.hl~ without an anionic structure may be a suitable modifier. The minor
component has an anionic structure and is a potassium salt linear alkyl (C,~ to C")
phosphate. The preferred ratio of these two ~~ ~~ varies depending on the
srri~s~i"n although the nonionic structure preferably is from 50 to 90% by weight
of the modifier. A 80:20 ratio by weight of the nonionic and anionic structure is
preferred Other preferred hydlu~ ;c modifiers are pcly~Jlu~yl~lle glycol
~Iyu~y.,llly- and fatty alcohol polyu,~yetlly' Other hydrophilic modifiers may
include alkyl phenol pulyw~y.,Llly- fatty acid polyu~y~ ly~ and fatty acid
amide polyw~y~ hy'
A preferred llydl~ ' modifier is Product No. 5808, available from G.R.
Goulston and Company in Monroe, North Carolina. This compound (hereafter "5808
Modifier) consists of a mixture of a food grade emulsifier, such as mono and
d;~jly~lid~ of edible fats and oils, and a salt of a linear alkyl phosphate. The push
to migrate or exude towards the surface comes from the highly distilled (>90%)
, '~,~.hlc, which by itself does not impart the surface wettability. Accordingly,
it is beneficial to meltlfuse the o'y~li;lc with the long chain l~ydlu~ùll~
havirlg the llydlu~llili~, group component so as to realize the significant impact on
surface wettability. This melVfuse operation may be performed by a prilling process
or a pastillizing process so that heat transfer takes place in a manner that will not
degrade the ~1~,~li~.
Olefin polymers do not disperse ~t; ' 1~, well in linear polyester ûr
,u~ly~i.t~,l. While an olefin component in theory might be ill.,UI~ ' ' into the
polyester at the pulyl.~.i~liull stage, this would be highly li~lv~.~ because
of the .., . to provide an injection facility for the added olefin or polyolefin , Moreover, yuly~Jlu~yl~ e will degrade ~ durmg the polyester
puly process. If the polyester were added during the yulyl..~,li~liull of
polyolefin, the entire process would be poisoned due to polar moiety.
WO 95/33882 1 ~ S 'C
21 90376
~ ~ C~ 20-
The ~ rPrcihility of linear polyester into the olefinic polymers can be
iGwllly improved by the ill.,.JllJUldliUII of a polar group material, e.g., EMA,which can be enh~mced further by a hydrophilic modifier. The linear polyester may
be produced by condensing one or more d;~bo~ , acids or a lower alkyl diester
S (e.g., I . ' ' - acid, isophthalic acid, phthalic acid, 2,5-; 2,6-; or 2,7 ~
d;~l,~J~I;., acid, succinic acid, sebaccic acid, adipic acid, azelaic acid, bibenwic
acid, and I ' yllu~~ acid or bis-p-~l~ .,lh.uIC) with one or
more glycols (e.g., ethylene glycol, 1,3-~ diol, 1,4-butadediol, neopentyl
glycol, and 1,4~ '). The preferred polyester is ~1~
10 ~.~.' ' ' , and a fiber grade polyester will hdve an intrinsic viscosity of about
0.64.
The polyester may be a copolymer containing a mixed hydroxylic acid and/or
ester forming acidic groups and may be a block copolymer formed from different
polyesters. The copolyester may contain rolymeric segments having a glass-transition
15 i . ~ of less than 0C so that the polyester is internally plasticized. The
polymer used for the polymeric segment should be capable of ~ ' _
~ly~ ' with the segments of the polyester through rPactive end groups, and
as hydroxyl or carboxyl groups, or being linked to polyester segments. Suitable
polymeric segments are pol,~ .., glyco~ and ~ ,.,c glycol, with the
20 rolyester segment typically being pol~"hyl~ . ' or polybutyl
h.~
This invention thus reduces or eliminates the drawbacks due to poor
y of a polyolefin resin and a polyeshr resin in each other. A
and process capable of providing continuous filaments or fibers is disclosed that
25 ~i ~ ~ ' 'y improves the dyeability of a polyolefin,
As known in the art, various specialized techniques have been developed for
application of disperse dyes to fibers. Unless the dyeing is carried out at 100C or
above, the rah of dyeing is slow. Dyeing with disperse dyes from aqueous solutions
at 120-130C to achieve rapid dyeings requires the use of closed high-pressure0 equipment. Jet dyeing has been introduced that permits l~;~h h..l~.dlL.~ dyeing and
of the dye onto the moving fabric through use of a venturi jet system.
Carriers permit faster dyeing at , ~ pressure and below 100C. Carriers are
~VO 9S133882
-21- 2190376
usually organic ~ . ' that can be emulsified in water and that have affinity forthe fiber polymer. The carriers penetrate the polymer, often swelling the fiber, and
aid passage of the disperse dye across the dye solution fiber interface mto the fiber.
Suitable carriers include aromatic l~ydlv~l/ull~ such as diphenyl and
- 5 ~ , phenolics such as o- and p l' J~ aromatics
such as the di- and trichloro-benzenes, aromatic esters including methyl salicylate,
butyl benzoate, ~ and l ' ' ' ~ Carriers must be removed after
dyeing.
A preferred swelling agent is of the type disclosed in U.S. Patent No.
10 5,358,537 to Shaw Industries, Inc. A l~vl~l,.u~"jlvv ~a~l compound as disclosed
herein avw ,' v'~ may also include â swelling agent, such as n-vyVlvllvA~l 2-
ulidv~lv, diethylene glycol, or n-octyl-2-~.-ulidu..e. A mixture of n-cyclohexyl-
2~ ulidùllv and diethylene glycol may be preferred. The mixture may also includean amphoteric agent, such as Wacogen NHv~0N, rh~ ~pn 132-N, or
15 thereof to act as â wetting agent or dye 1~ , thereby v ~ 'y enhancing
dying .~ For space dying and printing ,~ the dye mixture
preferably is in the form of a paste to allow for the selective placement of the mixture
on the yarn, fabAc, or calpet. For such ~ the viscosity of the mixture
may be adjusted from about 800 to about 3,000 centipoise (at 80F as measured by20 the Brookfield Viscometer with a No. 3 spindle). A selected thickener from group
consisting of guar gum, gum arabic, modified cellulose, locust bean gum, xanthene
gum and ,. ' ~ thereof may be used to obtain the desired viscosity. A dye
mixture comprising a disperse dye and the additives such as described above may be
applied to the POI~Y !/IU~IVI~V fibers. A dry heat may then be applied to the fibers and
25 the dye mixture ât a , v of from 95C to about 110C for time sufficient to
effect dispersion of at least a portion of the disperse dye into the pol.~l,.v~lv..v
fibers. Generally from 1 minute to 10 minutes of exposure to dry heat should achieve
the desired dispersion. The residual dye is then removed from the fibers.
A disperse dye mixture may thus be applied to the ~I~ylu~ v fibers in
30 vaAous ways. The dye mixture may be applied 'y along the length of
yarn formed from fibers using various well known techniques to create a desired
effect. One suitable method of dying fibers may be referred to as the "knit-deknit"
woss/33ss2 ~ P~
0376
-22-
dying technique. According to this method, the fibers are formed into a yarn which
in turn is knit, typically into a tubing, S_ The dye mixture is then
'y applied to the knit tubing. After dying, the tubing is unraveled and the
yarn thus has an j"t ~ 1 pattern. According to an alternative printing method,
5 tbe fibers are first formed into yarn which is then woven or knitted into fabric, or is
tufted into the carpet. A ~..~. ' flat screen printing machine, such as sold by
Peter Zimmer, Inc., may be used for applying the dye mixture to the fabric or carpet.
Continuous dyeing is carried out on a dyeing range where fabric or carpet is
'y passed through a dye solution of sufficient length to achieve initial dye
10 pPnP~r~ti~n Some disperse dyes may be sublimated under heat and partial vacuum
into polymer fiber by methods known in the art. Printing of polyolefin ~
made in accordance with our invention can be .' ' with disperse dyes by
heat transfer printing under pressure with sufficient heating to cause diffusion of
disperse dyes into tbe polyolefin. Block, flat screen, and heat transfer batch
15 processes, and engraved roller and rotary screen printing continuous processes may
be used. Different dye solutions may be jet-sprayed in ~ , ' sequence onto
fabric or carpet made of tbe . of this invention as the fabric passes under
the jets to form patterns. Dye solution may be metered and broken or cut into a
pattem of drops that are allowed to drop on a dyed carpet passing underneatb to give
20 a diffuse overdyed pattern on the carpet. C~ c dyeing of polyolefins is useful
when dyeing styled carpets consisting of several different fibers such as nylon,polyester, etc., and a polyolefin. Different styling effects can be produced by
controlling sbade depth on each type of fiber present. Acid, disperse and
' dyes, or ~ thereof, depending upon tbe fibers present, can
25 be employed to obtain styling effects. Also, styling effects obtained from a fiber
' can be achieved by making a fabric or carpet face from polyolefin yarns
containing varying amounts of ethylene alkyl acrylate copolymer. Just as tweed
effects can be produced in a nylon carpet by tufting with nylon fibers containing
different levels of amine ends, so too c~m these styled, tweed effects be produced in
30 a polyolefin fiber by controlling the: of ethylene aLk~ ' dye sites.
Print dyeing, space dyeing, and continuous dyeing can be carried out with fabrics
made from such yarns.
... .. _ ... ... . = = . = . =
WO g~i/33882 ~ 1 9 0 3 7~ -
23-
The invention can be further understood by referring to the following
examples in which parts and ~., ,, are by weight unless otherwise indicated.
In Examples 4, 5 and 6, polyester was added to the ~ul~ u~
xam~le 4
S A pul~,.u~ alloy ~ containing 82.5% by weight of a
' fiber grade of isotactic p~lyplu~ ..c as per Example 1, and 7% by
weight of a copolymer of ethylene l~ thrla~l~L~ along with 5808 Modifier (0.5%
by weight) was prepared by first dry mixing the polymers amd then melt blending the
mix im a 40 mm Berstorff extruder at 246C. The ethylene copolymer contained 20%lû by weight of the ~ la~l~' and had a melt index of 18 (ASTM
D-1238-89, 190C, 2.16 Ibs). The fiber grade polyester was blended in at 10% of
the total matrix. The resulting I ~ compatible polymer blend was cut into
nibs after water-quenching, which were then fed to a melt spinning apparatus, and
50-60 denier per filament fiber was spun at 260-265C. A rnineral-oil-based finish
15 containing anionic surfact~mts was applied to the fiber bundle after spinning, but
before drawing. The fibers were drawn times three to give a final denier of 18-20
per filament. The physical properties of specimens of the fibers so prepared were
tested, and the test results are set forth in Table Il. Specimens of the fibers were
knitted on a knitting machine to produce a tubular knit fabric. Samples of the fibers
20 were also tested for wetting ~
E~ le 5
A ~Iy~lu~ylu.~c graft . . containing 82.5% by weight of a
.,;~1 fiber grade of isotactic pul~ u~ as per E~xample 2, and 7% by
weight of a ~rafted copolymer of ethylene ~ lh~la~ ' (and containing thermal,
25 oxidative, and ultraviolet light stabilizers) was prepared by first dry mixing the
polymers along with 0.5% by weight of the 5808 Modifier. This mixture was
combined with the fiber grade cu~ul~ at 10% by weight of the total matrix The
resulting mixture was melt blended im a 40 mm Berstorff extruder at 246C in thepresence of sufficient free radical initiator peroxide per Example 2. The ethylene
30 copolymer contained 20% by weight of the ' ,~/la~ and had a melt
_ _ _ _ , _ _ _ _ _
wo ss/33ss2 . : . ~ r~.,u~
24- 2 1 9 0 3 7 6
index of 18. The resulting 1~ f,f ~ , compatible polymer blend was cut into nibsafter water-quenching, which were then fed to a melt spinning apparatus, and 50-60
denier per filament fiber was spun at 260-265C. A mineral-oil-based finish
containing anionic surfactants was applied to the fiber bundle after spinning, but
5 before drawing. The fibers were drawn times tbree to giYe a final denier of 18-20
per filament. The physical properties of specimens of the fibers so prepared were
tested, and the test results are set forth in Table Il. Specimens of the fibers were
knitted on a knitting machine to produce a tubular knit fabric. Samples of the fabric
were also tested for wetting ~
10 TABLE 11
fixample 4 Example 5
Physical (Unmodified (Alloy (Grafted
Properties I , '~ ) Modified PP) Modified PP)
Denier 1,450 1,500 1,470
(gmst9000
15 meters)
Tensile 2.5 2.0 2.2
(gms/den)
Elongation (%) 39.0 65.0 70.0
Exam~le 6
A ~ly~lu~ , . ' alloy and graft ~ ;.. containing 82.5%
by weight of a . ,,;al fiber grade of isotactic pu~y~lu~l~ having a melt index
in the range of 8-12 (ASTM D-1238-89, 23ûC, 2.16 Ibs) (and containing thermal,
oxidative, amd ultraviolet light stabilizers) and 7% by weight of an alloyed and grafted
copolymer of ethylene ~ ,LI~yl~wy' was prepared by first dry mixing the polymersalong with a 5808 Modifier (0.5% by weight), and then melt blending the mix withfiber grade Cu~ l at 10% of the total matrix in a 40 mm i3erstorff extruder at
246C in the presence of sufficient free radlcal initiator peroxide as per Example 2.
The ethylene copolymer contains 20% by weight of the ~ Lhyl~
WO 95133882 1-~
r~ -25- 2 1 9 0 3 7 6
and had a melt index of 18 (ASTM D-1238-89, 190C, 2.16 Ibs). The resulting
1~1~,,,l.~,.. ,~ compatible polymer blend was cut into ribs after water-quenching,
which were then fed to a melt spinning apparatus, and 50 to 60 denier per filament
fiber was spun at 260 to 265C. A mineral-oil-based ~mish containing anionic
5 surfactants was applied to the fiber bundle after spinning, but before drawing. The
fibers were drawn times three to give a final denier of 18 to 20 per filament. The
physical properties of specimens of the fibers so prepared were tested, and the test
results were about the same as those obtained with the fibers of Example 5.
Specimens of the fibers were knitted on a knitting machine to produce a tubular knit
10 fabric. Samples of the fibers were also tested for dyeing and wetting ..1,
according to the dyeing pror edure of Example 1.
While the prior art teaches the existence of ~ UIJYIUII~ illWI~ ' ' (by
grafting or blending) with ethylene-alkyl acrylate w~,ol~...~, the aboYe examples
illustrate that, in only certain limited amounts, a particular ethylene copolymer with
15 a proper . ' with polyester and hydrophilic modifier has the surprising
ability of making a ~ ~;ally acceptable, spinnable textile fiber of ~ulyl~lu~l~.le
that can accept disperse dyes sufficient to produce a deeply colored fiber with
superior physical properties.
Those sl~lled in the fiber-making art have long believed that any acrylate
20 additive produces a resin . that cannot be spun at modern high-speed
production without separation of the, . Further, the addition of many
additives, including acrylates and acetates, imparts a ~ feel and smell to
tbe fLnished fiber goods, partially as a result of ~ during the spinning and
drawing process. Fiber e typically imparts terrific shear forces to a
25 polymer . and~drawdown"ratiosof20-lOO:l,whichmakesfiber-forming
polymers very intolerant of many additives routinely employed in; . ~ having
other uses. Any ~i '.y or lack of uniformity in a polymer, . can
- result in a break when the fiber is stretched or drawn down to its final, often very
thin, diameter. As a . , those skilled in the fiber-making art have generally
30 not looked to . - for other end uses as acceptable in fiber ~ A.
~ i~"dall~ in areas where historical experience suggests, . ' ' ~. The critical
nature of the invention is ~ 11 ' ' in that a 0.2 to 3.0% by weight limitation on
WO 95133882 r~,l" ~, r
" Ir ~ -26- ~ ~ q 0 3 7 6
alkyl acrylate component in the: , in c....,l.; ,-~;..,. with a less than about
10% by weight ethylene content attributed from the alkyl acrylate copolymer, is
required to produce the desired results sufficient to achieve commercial ~r~Ppr~hil jty.
The l.~ u~ ilic modifier provides additional ~ n to bridge polyester
5 with ~Iy~lvy.~
The ethylene copolymer is i.lwll ' into the ~IYIJIU~YI~IIC by either
grafting or physical blending. Those skilled in the fiber-making art have recognized
that l~ul.~ u~Jyl~ /EVA ~ , cannot produce a spinnable fiber under modern
fiber-making conditions, but instPad this ~o~ ir ~ very quickly degrades to
10 produce noxious amounts of acetic acid. No other known CO~Iylll~ are believed to produce ~ ;~l y acceptable dyeable fibers in ,1...l1.'-''';..ll with
p~lylJ~ u~
A series of samples was made as described in Example 5 and was evaluated
with a æries of disperæ dyes according to the dye procedure described earlier. The
15 results are æt forth in Table nI. Light fastness and crock fastness tests were also
performed on yarns at 2-20 deniers per filament. r~mrl~hlP results would be
expected for both the Example 4 and Example 6 samples.
.
Table Ill
Dye Exhaustion
20Disperse Dyes Light Fastness Crock Fastness E~xhaust/
(3% r ) Xenon Arc (AATCC 8-1985) Yield
(AATCC 16E-40 hrs.)
Dry Wet
Disperæ Yellow 54 5 S S S
Disrerse Yellow 86 5 4-5 4-5 S
Disperæ Blue 35 5 5 5 s
25Disperse Blue 87 S 5 4-5 5
Disperse Blue 291 5 5 4-5 5
Disperse Blue 60 5 4 4 5
W0 9513388~ r. ~
27- 2 1 9 0 3 7 6
Disperse Red 60 5 4 4 5
Disperse Orange 25 5 5 5 5
t
Dye exhaust, set forth in the last column, has been used as the basis for
identifying dyes suitable for the polymer. Of all the workhorse dyes that are known
S to exist, most disperse dyes should produce acceptable results if polyester is added
to the POIY~UIU~JI~ mixture. The most important criteria for dye selection, in
y times, are dye exhaust and fastness retention. It is important that the
substrate in a woven, tufted, knitted, or nonwoven product readily pick up the dye
from the bath and retain it, thereby reducing ~ ' waste and improving
10 economic utility of the expensive dye. Hardly any differences appear to exist when
these criteria are used to evaluate dye ,~,r~ between 100% polyester fabric
and enhanced polyolefin fabric.
While those skilled in the fiber-making art have recogniæd that polyester fiber
is well accepted for disperse dye ~ it was not recognized that polyester at
15 a very minute level (d~ I 0. 1 % by weight of the polyolefin resin matrix)
creates voids that ll~ ,duu~lr enhance the dye uptake. The processibility of this
is also ~ / improved by adding a hydrophilic modifier. Though
not bound by any theory, it is believed that increased wettability due to the combined
nature of polarity and llydlu~ll;L~ y (the polar group material combined with
20 IllUl~U~Iy~lidc and linear alkyl phosphate) and . ' ' ~, ' changes caused by the
addition of polyester causes the disperse dyes to diffuse into the fiber very rapidly
(i.e., high exhaust) and tend to stay (i.e., increased light fastness ~ l . ,. . ;~,;.
The above ~ , is much more dyeable than prior art POIY~UIUI~J~
materials. It is speculated that the t ' of increased dispersive and polar
25 functions far exceeds the surface energy that is critical for adequate wetting to occur
on polyolefin surfaces. Neither a polar material nor a hydrophilic modifier on its
own is capable of imparting such a highly desirable ~ ';r that produces good
spreading and therefore even dyeing. With a lesser barrier to overcome, the above
material therefore is Wl~t liv~ly easy to dye compared to W~l~. "y modified
30 poly,ulut~J~ materials.
wosS/33ss2 2190~7~ 5.~ - ~
28-
Hydrogen bonding of the dyestuff molecule to the carbonyl oxygen of the ester
grouping in methyl acrylate is believed to be the attachment mode of the disperse
dyestuff. The disperse dyestuff exhibits excellent retention, indicating strong
chemical affinity between the r ~ ,y in the ester group and dyestuff. The
5 penetration of dye molecules is facilitated by creating a IIJdI~ r~ 'lir structure with
voids created by the , of polyester.
To enhance the dyeability ..l, ~ , especially with cationic dyes, several
attempts were made to introduce a sulfonic group on a polymer. A sulfonic group
on a polymer should improve dyeing, especially utilizing cationic dyes instead of
10 disperse dyes. This invention discloses a method of causing ~ r~ acid to
react with an olefin (or polyolefin) or with an alkyl acrylate copolymer.
Sulîu~,vl~ t~.~ were made by the poly~ ';.". reaction of the selected
d;~bvAyli., acids (A's) and glycols (G's) to produce a linear structure shown below
in a simplified form:
HO-G-A~A-G--A-G-A{i OH
I I
SO;Na+ SO3 Na+
A = An aromatic d;~w~ylic acid moiety
G = An aliphatic or ,,~ ; glycol residue
~H = Hydroxy end groups
The ~oly~ reaction, in which a carboxyl group (-COOH) reacts
with a hydroxyl group (-OH) to from ester linkages, is carried out at high
~ ,~ (275C to 290C) and low pressure (<1 torr) to produce number-
average molecular weights in the 10,000 to 15,000 range. The thermal stability of
25 a polymer formed under such extreme conditions is ade4uate for most fiber spinning
process ~ Adding a sulfonic group to the polyester is much easier than
adding a sulfonic group to ~Iy~lu~ . It may be possible, however, to produce
a sulfonated hydrophilic modifier.
As indicated in the above structure, some of the aromatic di~bu~ylic acid
30 units have sodiosulfo (-S0;Na') l-~ at~ached. The ~ulru~ feature
of this invention requires more ionic groups in order to make the entire fiber structure
.. _ .. _ . . .. .. ... . ..... . . .... .. . . . . ..
W0 95133882 ~ r~
f ~ 29- ~ 1 9 0 3 7 6
more acceptable to cationic dyes. The hydrophilic nature of these ionic groups also
imparts improved disperse dyeability. Several basic dyes were attempted on a fiber
composed of PUIYIJIUIJJL~ alkyl acrylate copolymer, and ~ulro~ul~, with and
without additional hydrophilic modifier.
- 5 Basic dyes have been used extensively for dying silk, cellulose acetate, and
~Iy~ y' ' 'Ir~ (acrylic or modified acrylic) fibers. The positively charged colored
ion of the basic dye, the cation, is attracted strongly by the negatively charged ions
in the fiber. Fibers dyed with basic dyes usually exhibit good light and wash
fastness. As a class, basic dyes have a high color value and are ~ by
brilliant shades. Basic dyes are thus well suited for application to fibers composed
of negatively charged polymer molecules. Since basic or ionic dyes contain positively
charged ions, bonds can be easily formed between the cation of these dyes and anionic sites in the fibers. At the conclusion of the dye cycle, the dye cations are
almost completely absorbed or complete exhausted by the fiber.
Based upon this I ' " a sulfonated group was introduced to the
polyester component of the IJUIy~lU~ [ mixture by a grafting technique, as
described above. Tests were conducted using basic workhorse dyes, including Basic
Blue-41 and Basic Red~6. Each of these dyes, when used in cu~.j, with a
puly,ulul~yl~ mixture including a ~ulrupul~r~ as described above, yielded brilliant
shades on fibers. A grafting technique is preferably employed to include the
sulfonated group on the polyester.
From the above examples, it may be understood that the addition of both polar
group material and the hydrophilic modifier to a l~uly~JIu~Jyl~ based material will
result in a material tllat is hydrophilic and thus "wettable." The polar group material
may be an EMA material as described above, or may be either an acrylic acid
comprising about 0.1 to 2% by weight of the puly~lu~l~llc, or a maleic anhydridecomprising about 0.1 to 10%, and preferably 0.1 to 2%, by weight of the
- POIY~JIU~YI~ C~ The l~ydlulJIIilic modifier may be either a nonionic or anionic
material and may be used in ~ wherein the l.y.ll~ l ~ 'lir modifier is present
in the amount of between 0.1 and 2%, and preferably between 0.4 and 1.0%, of theweight of the POIY~IUIJYI~ and polar group material. The addition of polyester thus
is facilitated by this ~ 1 g, 1. ~. l. . ;~I;.
.
WO 95/33882 r~u~ s c
~ ~t~ 2~ 90376
The polymers as described above thus have significantly improved hydrophilic
.1.~,,.~ ~ .;`1;. ~ that enable the polymers to be formed into fibers suitable for fabrics
or into injection molded films. These polymers provide improved dyeability and
h~ uly make the polymer dyeable with a broad rang~ of disperse dyes. This
5 increased dyeability feature is of great importance because certain disperse dye
molecules are too large to diffuse into the fiber core of prior art ~Iy~JIu~ , fibers,
but these same molecules may penetrate into the improved ~Iy~,luL,yl~l~c fibers of
this invention. Dye selection therefore becomes less complex, and the final shade of
the dyed product is brighter, deeper, and sharper than prior art . This
10 wettability ~1.,.~....;~1;~ also should provide excellent exhaustion for the dyed
products since the dye molecules, once in place in a fiber, should tend to stay in
place. Improved wash fastness and crock fastness results may thus be expected, and
the product should be both wettable and dyeable for various al.l,li. l;....
A hydrophilic dyeable and wettable polymer provides highly desirable material
15 features, such as I y, wickability, and extra comfort. These attributes are
highly desired in product l~l~pl;~ such as diapers, adult products,
and sanitary napkins, where a nonwoven web comes in contact with the body or entry
point for any fluid pPnP~ti~n
The .,~ .. of this invention may be used for forming both a highly
20 wettable and dyeable polyolefin, as well as a resilient polyolefin. The
is ~ ~ly suitabie for forming improved ~lyl~lu~l~ -based polyolefin. To
substantially imcrease accept~mce of ~Iyylu~ , as a suitable ~ for
various ~I~Pl;. ~ as discussed above requires increased dyeability and increasedwettability. Moreover, the ~Iy~lu~Jyl~ . of this invention may be easily
25 formed as a fiber that is spinnable and ideally may be formed into a fabric sheet
including nonwoven fibers.
roly~ulu~yl~,.." and polyester are generally not considered compatible materialsfor forming continuous fibers due to the significant difference in their softening amd
melting t~ ~...h._~. The ethylene methyl acrylate acts as a .-~ - to allow
30 the polyester to adhere to the ~Iy~lulJyl~ . This, . 1i7~til~n is enhanced by
the inclusion of the hydrophilic modifier as discussed above. This modifier also
W0 95133882 r~
31- 2 ~ 9 Q3 7~
enhances the ~ ;L.;li~y of the c~ -" to form spinnable fibers and imparts
a desired resiliency and softness to the fabric formed by these fibers.
While the techniques of the present invention are ~u ' 'y well suited for
increasing both the dyeability and the wettability ..1, - d' ~` ' ;"1;' ` of IJulylJlulJy~ it
S should be understood tbat the selected polar group material, such as an ethylene
copolymer including alkyl acrylate as described above, in ' with a
Lydlu~lil;c modifier as described above, may be used to substantially increase the
wettability ~ , of other polymeric materials, such as polyester, nylon, and
acetate, all of which may be used to form fibers. Those skilled in the art will also
10 appreciate that fibers made of a polyolefin material as disclosed herein may be used
for various woven or nonwoven n~ to form either fabrics or mats. The
fibers may also be combined with other common stock materials, such as pulp or
paper stock, to form a desired wettable and breathable fabric or mat. As previously
explained, the concept of the present invention may also be used for form materials
15 such as fibrillated films that do not imclude fibers.
Various '~ - to the modified ~IYJ~ fibers and to the
techniques described herein for forming amd dyeing such fibers should be apparent
from the above description of those preferred . ~L " Although the invention
has thus been described in detail for these, L ' it should be understood that
20 this . ,' is for illustration and that the invention is not limited to these
. ~ " Alternative fibers and forming and dyeing techniques will thus be
apparent to those skilled in the art in view of this disclosure, and such alternative
fibers and techniques may be performed without departmg from the spirit of the
invention, which is defined by the claims.
