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Patent 2067398 Summary

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(12) Patent Application: (11) CA 2067398
(54) English Title: METHOD FOR MAKING BICOMPONENT FIBERS
(54) French Title: PROCEDE DE FABRICATION DE FIBRES BICOMPOSEES
Status: Dead
Bibliographic Data
(51) International Patent Classification (IPC):
  • D01F 8/06 (2006.01)
  • D01F 8/14 (2006.01)
(72) Inventors :
  • TABOR, RICKY L. (United States of America)
  • LANCASTER, GERALD M. (United States of America)
  • BIESER, JOHN O. (United States of America)
  • FINLAYSON, MALCOLM F. (United States of America)
(73) Owners :
  • THE DOW CHEMICAL COMPANY (United States of America)
  • THE DOW CHEMICAL COMPANY (United States of America)
(71) Applicants :
(74) Agent: SMART & BIGGAR
(74) Associate agent:
(45) Issued:
(86) PCT Filing Date: 1990-08-07
(87) Open to Public Inspection: 1992-02-20
Examination requested: 1997-08-01
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/US1990/004410
(87) International Publication Number: WO1992/002669
(85) National Entry: 1992-04-06

(30) Application Priority Data: None

Abstracts

English Abstract

2067398 9202669 PCTABS00010
A method is disclosed for making thermoplastic bicomponent fibers
by contacting under thermally bonding conditions (a) a first
component being at least one high performance thermoplastic polymer,
such as PET, PBT, nylon or the like, and (b) a second component
which is olefinic and which forms at least a portion of the
fiber's surface characterized by (b) including at least one grafted
linear ethylene polymer having pendant succinic acid or succinic
anhydride groups; whereby the fiber is dyeable. The bicomponent
fibers made by this process can be in a variety of shapes (e.g.,
round, oval, trilobal, flat, or hollow) and configurations (e.g.,
symmetrical sheath/core or side-by-side or asymmetrical
crescent/moon). The succinic acid or succinic anhydride groups are provided
by grafting, respectively, maleic acid or maleic anhydride onto
the linear ethylene polymers especially by a process wherein the
grafting is done in a twin-screw, co-rotating extruder with the
maleic acid or maleic anhydride being injected into a pressured
zone of the extruder. The acid containing grafted linear ethylene
polymer or polymer blends are dyeable in contradistinction to
ungrafted linear ethylene polymers.


Claims

Note: Claims are shown in the official language in which they were submitted.


WO 92/02669 PCT/US90/04410

-23-




Claims:

1. A method for making a thermoplastic bicomponent
fiber by contacting under thermally bonding conditions
(a) a first component being at least one high
performance thermoplastic polymer, and (b) a second
component which is olefinic and which forms at least a
portion of the fiber's surface
characterized by (b) including at least one grafted
linear ethylene polymer having pendant succinic acid or
succinic anhydride groups: whereby the fiber is dyeable.
2. The method defined by Claim 1 wherein said
bicomponent fiber is prepared by coextruding (a) and
(b) into a fiber having a round, oval, trilobal,
triangular. dog-boned, flat or hollow shape and a
symmetrical or asymmetrical sheath/core or side-by-
side configuration.
3. The method defined by Claim 2 wherein said
bicomponent fiber has a round shape and a
sheath/core configuration.
4. The method defined by any one of the
preceding Claims wherein (a) is a polyester or a
polyamide.

WO 92/02669 PCT/US90/04410
-24-

5. The method defined by Claim 1 wherein said
bicomponent fiber is prepared by coextruding (a) and
(b) into a fiber having a sheath/core configuration,
and wherein (a) is a polyester, and wherein (b)
includes a polymer blend of a grafted linear
ethylene polymer having pendant succinic acid or
succinic anhydride groups and at least one ungrafted
linear ethylene polymer.
6. The method defined by Claim 5 wherein (a) is
polyethylene terephthalate or polybutylene
terephthalate and wherein (b) is a polymer blend of
a grafted linear high density ethylene polymer and
an ungrafted linear low density ethylene polymer.
7. The method defined by Claim 2 wherein said
fiber is formed under melt blown, spunbond or staple
fiber manufacturing process conditions.
8. The dyeable thermoplastic bicomponent fiber
obtainable by the method of any one of the preceding
Claims.
9. A method of bonding high performance fibers
by blending the high performance fibers with binder
fibers and heating the fibrous mixture to near the
melting point of the binder fibers to thermally bond
the binder fibers to the high performance fibers
characterized by providing the dyeable thermoplastic
bicomponent fibers of Claim 8 as the binder fibers.
10. The method defined by Claim 9 wherein said
high performance fiber is a polyester, polyamide,
cellulosic or wool, or a mixture thereof.

WO 92/02669 PCT/US90/04410
-25-
11. The product obtainable by the method of
Claims 9 or 10.
12. An adhesive polymer blend for fiber forming
use in (b) of the method of Claim 1 wherein the
blend includes at least one grafted linear ethylene
polymer having pendant succinic acid or succinic
anhydride groups and at least one ungrafted linear
ethylene polymer.
13. Use of an adhesive polymer blend in
preparing dyeable fibers in (b) of the method of
Claim 1 by contacting said fiber with a water
soluble cationic dye wherein the blend includes at
least one grafted linear ethylene polymer having
pendant succinic acid or succinic anhydride groups
and at least one ungrafted linear ethylene polymer.
14. The fiber of Claim 8 for dyeing use by
contacting said fiber with a water soluble cationic dye.
15. The fiber of Claim 8 in the form of a fabric.

Description

Note: Descriptions are shown in the official language in which they were submitted.


2 ~
W092/02669 PCr/US90/0~10




MÉTHOD FOR MA~ING ~lCOMPON~NT FI~ERS

The preser.t inver.ticn pertains tc ~yeabie
thermoplastic bicomponent fibers ar,a a method of
preparatior.. These bicomponent fibers are characterized
by contacting under thermally bonding conditions (a) a
first component comprising at least one high performance
thermoplastic polymer. and (b) a second component
comprising at least one grafted linear ethylene polymer
having pendant succinic acid or succinic anhydride
groups. The bicomponent fibers can be prepared by
coextruding (a) and (b) lnto fiber having a round. oval.
trilobal. triangular. dog-boned. flat or hollow shape
and a sheath/core or side-by-side configuratior.. ~he
bicomponent fiber can be coextruded using me' blown.
spunbond or staple fiber manufacturing process
conditions. The presen~ invention also pertains to a
method of bonding high performance fibers using the
dyeable thermoplastic bicomponent fibers of the present
invention as binder fibers.
Various olefin fibers. i.e... fibers in which
the fiber-forming substance is any long chain, synthetic
polymer of at least 85 weight percent ethylene.
propylene, or other olefin units, are known from the
prior art. The.mechanical properties of such fibers are

W092/02669 2 0 6 7 ~ ~ ~ PCT/US90/0~10
--2--

generally related in large part to the morphology of the
polymer. especially molecular orientation and
crystallinity. Thus, crystalline polypropylene fibers
and filaments are items of commerce and have been used
in making products such as ropes ! non-woven fabrics. and
woven fabrics. Polypropylene is known to exist as
atactic (largely amorphous). syndiotactic (largely
crystalline), and isotactic (also largely crys~alline).
The largely crystalline types o~ poiypropylene (PP).
including both isotactic and syndiotactic~ have found
wide accep~ance in certain applications in tne ~or~i of
fibers.
Othe~r types of polyolefins which have been
suitably formed into fibers include linear ethylene
polymers. such as linear high density polyethylene
(HDPE) having a density in the range of 0.941-0.965
grams/cubic centimeter ~s!cc) and linear low density
polyethylene (LLDPE) ha~ing a density typically in the
range of low density polyethylene (LDPE) and linear
medium density polyethylene (LMDPE). or from 0.91 g/cc
to 0.94 g~cc. The densities of the linear ethylene
polymers are measured in accordance "ith ASTM D-792 and
defined as in ASTM D-1248. These polymers are prepared
using coordination catalysts and are generally known as
linear polymers because of the substantial absence of
branched chains of polymerized monomer pendant from the
main polymer backbone. LLDPE is a linear low density
ethylene polymer wherein ethylene has been polymerized
along with minor amounts of a,~-ethylenically
unsaturated alkenes having from three to twelve carbon
(C3-C12) atoms per alkene molecule, and more typically
four to eight (C4-C8). Although LLDPE contains short
chain branching due to the pendant side groups

2/02 2~3~
W09 669 PCTtUS90/0~10
--3--

introduced by the alkene comonomer and exhibits
characteristics of low density polyethylene such as
toughness and low modulus, it generally retains much of
the strength, crystallinity. and extensibility normally
found in HDPE homopolymers. In contrast, polyethylene
prepared with the use of a free radical initiator, such
as peroxide, gives rise to highly branched polyeJhylenes
known as low density polyethylene (LDPE~ and sometimes
as high pressure polyethylene (HPPE) and ICI-type
polyethylenes. Because of unsuitable morphology.
notably long chain branching and concom -ant hi=:n me!~
elasticity, LDPE is difficuit to form into a fiber and
has inferior properties as compared to LLDPE. HDPE and
PP fibers.
One appiication of certain fibers such as. for
example. polyvinyl chloride. low melting polyester and
polyvinylacetate. has been the use of such fiberâ as
binder fibers by blending the binder fiber with high
performance natural and/or synthetic fibers such as
polyesters (e.g.. polyethylene terephthalate (PET) or
polybutylene terephthalate (PBT)). polvamides.
cellulosics (e.g.. cotton). modified cellùlosics (e.g..
rayon), wool or the like, and heatins the fibrous
mixture to near the melting point of the binder fiber to
thermally weld the binder fiber to the high performance
fiber. This procedure has found particular application
in non-woven fabrics prepared from performance fibers
which would otherwise tend to separate easily in the
fabric. However. because of the unavailability of
reactive sites in the olefin fibers, the bonding of
olefin fibers to the performance fibers is characterized
by encapsulation of the performance fiber by the melted
olefin fiber at the thermal bonding site by the

2~)~7~
W092l02669 PC~/US90/0~10
--4--

formation of microglobules or beads of the olefin fiber.
Moreover. it is difficult to achieve suitable thermal
bonding in this fashion because of the poor wettability
of a polar performance fiber by a nonpolar olefin fiber.
Another problem which has hampered the
acceptance of olefin fibers is a lack of dyeability.
Olefin fibers are inherently difficult ~o dve. because
there are no sites for the specific attraction of dye
molecules, i.e.~ there are no hydrogen bonding or ionic
groups, and dyeing can only take place by virtue of weak
van der Waals forces. Usually. such fibers are colored
by adding pigments to the polyolefin meit befor~
extrusion. and much effort has gone nt3 pigmentation
technology for dispersing a dye into the polyolefin
fiber. This has largeiy been unsuccessful because of
- the poor lightfastness. poor fastness to dry cleaning.
generally low color bu id-up. stiffness, a necessitY for
continuous production changes. poor color uniformity,
possible loss of fiber strength and the involvement of
large inventories.
Bicomponent fibers are tyDically fabricated
commercially by melt spinning. In th s procedure, each
molten polymer is extruded through a die. e.g., a
spinnerette, with subsequent drawing of the molten
extrudate, solid-fication of the extrudate by heat
transfer to a surrounding fluid medium. and taking up of
the solid extrudate. Melt spinning may also include
3 cold drawing, heat treating, texturizing and/or cutting.
~ An important aspect of melt spinning is the orientation
; of the polymer molecules by drawing the polymer in the
molten state as it leaves the spinnerette. In
accordance with standard terminology of the fiber and




.

W092/02669 PCT/US90/0~1


filament industry, the following definitions apply to
the terms used herein:
A "monofilament" (also known as "monofil")
refers to an individual strand of der.ier greate~ than
1~, usually greater than 30:
A "fine denier fiber or "filament" refers to a
strand of denier less than 15:

A "multi-filament" (or "multifil") refers to
simultaneously formed fine denier filaments spun in 2
bundle of fibers, generally containir.g a~ le~st 3.
preferably at least 15-lO0 fibers and can be se~/eral
hundred or several thousand:
An "extruded strand" refers to an extrudate
formed by passing polyme~ through a forming-orific2.
such as a die:

A "bicomponent fiber" refers to a fiber
comprising two polymer componencs. each in a continuous
phase. e.g. side-by-side or sheath/core:
A "bicomponent staple fi~er" refers to a fine
2~ denier strand which have been formed at. or cu~ to.
staple lengths of generally one to eight inches (2.7 to
20 cm).
The shapes of these bicomponent fibers.
extruded strands and bicomponent staple fibers can be
any which is convenient to the producer for the intended
end use, e.g.~ round, trilobal, triangular. dog-boned,
flat or hollow. The configuration of these bicomponent
fibers or bicomponent stapie fibers can be symmetric
(e.g., sheath/core or side-by-side) or they can be

~7 ~
W092/02669 PCT/US90/0~10
--6--

asymmetric (e.g.. a crescent/moon con~iguration within a
fiber h~aving an overall round shape).
Convenient references relating to fibers and
filaments, including those of man made thermoplastics,
and incorporated herein by reference, are, for example:
(a) Encvclopedla of Polvme~ Science and
Technolo~. Interscience. New York. vol. 6 (1967) . pp.
505-555 and vol. 9 (1968), pp. 403-440:
10 .
(b) Kirk-Othmer Enc-Jclopedia of Chemical
Technolo~v. vol. 16 for "Olefin Fibers". John Wiley and
Sons, New York. 1981. 3rd edition;
~5 (c) Man Made and Fiber and Textile Dictionarv.
Celanese Corporation:
(d) Fundamentals of Fibre Formation--The
Science of Fibre Spinning and Drawing. Adrezi, Ziabicki.
John Wiley and Sons. London~New York. 1976;
(e) Man Made Fibres. by R. W. Moncrieff.
John Wiley and Sons. London/New York, 1975.
Other references relevant to this disclosure
2~ include U.S. Patent No. 4.644.045 which describes spun
bonded non-woven webs of LLDPE having a critical
combination of percent crystallinity, cone die melt
flow, die swell, relation of die swell to melt index,
~ .30 and polymer unifor~ity: European Patent Application No.
-~87304728.6 which describes a non-woven fabric formed of
heat bonded bicomponent filaments having a sheath of
LLDPE and a core of polyethylene terephthalate.
In CA 91 :22388p (1979) there is described a
fiber comprising polypropylene and ethylene-maleic

W092/02669 ~r~ PcT/US90/O44lO
--7--

anhydride graft copolymer spun at a 50:50 ratio and
drawn 300 percent at 100~C. and a blend of the drawn
fibers and rayon at a 40:60 weight ratio carded and
heated at 145C to give a bulky non-woven fabric.
However, polypropylene is disadvantageous in some
applications because of its relatively high melting
point (145CC). and because of the relatively poor hand
or feel imparted to fabrics made thereof. Poor hand is
manifested in a relati~ely rough and inflexible fabric,
as opposed to a smooth and flexible fabric.
U.S. Patent No. 4.684,576 describes the use of
~lends of HDPE grafted with maleic acid or maleic
anhydride to give rise to succinic acid or succinic
5 anhydride groups along the polymer chain with other
olefin polymers as an adhesive, for example~ in
extrusion coating of art~cles. as adhesive layers in
- films and packaging, as hot mel~ coatings. as wire and
cable interlayers, and in other similar applications.
20 Similar references describing adhesive blends containing
HDPE grafted with unsaturated carboxyiic acids,
primarily for laminate structures. include U.S. Patent
Nos. 4.460.632; 4.394.485: and 4,230,830 and U.K. Patent
Application Nos . 2.081,723 and 2.113,696.
A method has now been discovered for making
thermoplastic bicomponent fibers by contacting under
thermally bonding conditions (a) a first component being
at least one high performance thermoplastic polymer, and
3 (b) a second component which is olefinic and which forms
at least a portion of the fiber's surface characterized
by (b) including at least one grafted linear ethylene
polymer having pendant succinic acid or succinic
anhydride groups; whereby the fiber is dyeable. These
novel dyeable thermoplastic bicomponent fibers have

':~
,



.
,' .

W092/02669 2 ~ ~ 7 ~ PCT/USgo/o~lo '
--8--

superior hand, a relatively low melting or bonding
temperature~ superior adhesive properties. superior
dyeability and superior adhesion of the components
within the bicomponent fiber. The bicomponent fiber can
be prepared by coextruding (a) and (b) into a fiber
having a symmetrical or asymmetrical sheath/core or
side-by-side configuration and a round. oval. trilobal.
triangular, dog-boned~ flat or hollow shape. Component
(a) can be a polvester (such as polyethylene
terephthalate or polybutylene terephthalate) or a
pol-iamide (such âS rylon). Componen' (b) can be a
polymer blend of a grafted linear ethyler.e ?olymer
having pendant succinic acid or succinic anhydride
groups and at least one ungrafted linear ethylene
polymer. The bicomponent fiber can be formed under melt
blown. spunbond or staple manufacturing process
conditions.
In a further aspect of the invention, there is
provided a method of bonding high performance natural
and/or synthetic fibers such as polyester (e.g.. PET or
PB,), polyamides (e.g.. nylon). cellulosics (e.g..
cotton). modified cellulosics (e.g.. rayon). wool or the
like. by blending dyeable thermoplastic bicomponent
fibers of the present invention used as binder fibers
with the high performance fibers and heating the fibrous
mixture to thermally weld the binder fiber to the high
performance fibers.
Tn still another aspect. the invention provides
a fabric comprising dyeable thermoplastic bicomponent
fibers.
In still another aspect, the invention provides
a :abric comprising dyeable thermoplastic bicomponent


.



- . .
.



,

2 ~ '3
i W092/02669 PCT/US90/0~10
_g_

fibers as binder fiber blended with performance fibers.
wherein the bicomponent binder ~ibers are bonded to the
performance fibers.
In a still further aspect of the invention.
there is provided an adhesive polymer blend for use as a
component in making the dyeable thermoplastic
bicomponent fibers. The polymer blend comprises (a) at
least one grafted linear ethylene polymer having pendant
succinic acid or succinic anhydride groups and (b) at
least one ungrafted linear ethylene polymer.
In yet another aspect. there s provided a
dyeable thermoplastic bicomponent fiber characterized b~
(a) a first component comprising at leas~ one high
performance thermoplastic polymer. and (b) a second
component comprising at leas~ one grafted linear
ethylene polymer having pendant succinic acid or
succinic anhydride groups which have been contacted
under thermally bonding conditions.
The linear ethylene polvmers used for grafting
can be linear HDPE and/or LLDPE. The density of linear
HDPE before grafting can be about O.g4 to 0.97 g/cc. but
is typically between about 0.945 and 0.965 g/cc. while
that of LLDPE before grafting can be about 0.88 to
0.94 g/cc, but is typically between about 0.91 and 0.94
g/cc. Typically, linear HDPE and LLDPE will have about
the same density before and after grafting. but this can
vary depending on the particular linear ethylene polymer
properties, graft level, grafting cond~itions and the
i- like. The linear ethylene polymer before grafting has a
melt index (MI) measured at 190~C/2.16 kg from about 0.1
to about 1000 grams/10 minutes, but typically less after
grafting. For example, linear HDPE with a 25 MI and a


.




., , ~ . . . .

W092/02669 2 ~ ~ ~ 3 ~ ~ PCT/US90/0~10
-- 1 0--
-




0.955 g/cc density grafted to a level of about 1 weight
percent maleic anhydride (MAH) has a MI after grafting
of about 16-18 grams/10 minutes. Melt index herein is
measured in accordance with ASTM D1238 condition
190C/2.16 kg (also known as condition "E"). The MI of
the ungrafted linear ethylene polymer used for grafting
is selected depending on the specific melt spinning
procedure employed and whether or not the grafted linear
ethylene polymer is employed alone or in a blend with
another linear ethylene polymer.
The grafting of succinie acid or succinic
anhydride groups may be done by methods described in the
art which ~enerally involve reac~ing malei^ acid cr
maleic anhydride in admixture with heated polymer.
generally using a peroxide or free radical initiator to
accelerate the graftlng. The maleic acid and maieic
anhydride compounds are known in these relevant arts as
having their olefin unsaturation sites conjugated to the
acid groups. Fumaric acid. an isomer of maleic acid
which is also conjugated. gives off water and rearranges
to form maleic anhydride when heated. and thus is
operable in the present invention. Grafting may be
effected in the presence of oxygen, air hydroperoxides.
or other free radical initiators. or i,n the essential
absence of these materials when the mixture of monomer
and polymer is maintained under high shear and heat
conditions. A convenient method for producing the graft
polymer is extrusion machinery, although Brabender
mixers or Banbury mixers. roll mills and the like may
also be used for forming the graft polymer. It is
preferred to employ a twin-screw devolatilizing extruder
(such as a Werner-Pfleiderer twin-screw extruder)
wherein maleic acid or maleic anhydride is mixed and

~ o ~
W092/02669 PCT/US90/0~10


reacted with the linear ethylene polymer(s) at molten
temperatures to produce and extrude the grafted polymer.
The anhydride or acid groups of the grafted
polymer generally comprise from about 0.001 to about
10 wei~ht percent, preferably from about 0.01 to about
5 weight percent. and especiaily from 0.1 to about 1
weight percent of the grafted polymer. The grafted
polymer is characterized by the presence of pendant
succinic acid or anhydride groups along the polymer
0 chain. as opposed to the carboxylic acid groups obtained
by the bulk copolymerization of ethvlene ~ith an
ethylenically unsaturated carboxylic acid such as
acrylic acid as disclosed in Furopean ~atent Application
number 88116222.6 (EP Publication number 0 311 860 A2).
Grafted linear HDPE is the preferred grafted linear
ethylene polymer.
The grafted linear ethylene polymer(s) can be
- 20 employed singly or as a component in a polymer blend
with other linear ethylene polymers. The polymer blend
preferably contains from abou~ 0.5 to about 99.~ weight
percent of the grafted linear ethylene polymer. more
preferably from about 1 to 50 weight percent grafted
linear ethylene polymer~ and especially from about 2 to
15 weight percent grafted linear ethylene polymer. The
polymer blend may also include conventional additives,
such as dyes, pigments, antioxidants, UV stabilizers,
spin finishes, and the like and/or relatively minor
3 proportions of other fiber forming polymers which do not
significantly alter the melting properties of the blend
; or the improved hand obtained~in fabrics containing
fibers employing LLDPE as a polymer blend component.

- WO 92/02669 2 ~ S 7 ~ f ~ PCT/US90/0~10
-- 1 2--

The LLDPE employed either as the grafted linear
ethylen~e polymer component or as the ungrafted component
in the dyeable thermoplastic bicomponent fiber,
comprises at least a minor amount of a C3-C 2
olefinically unsaturated alkene, preferably a C4-C8
olefinically unsaturated alkene. and 1-octene is
especially preferred. The alkene may constitute from
about 0.5 to about 35 percent by weight of the L~DPE,
preferably from about l to about 20 weight percent. and
most preferably from about 2 to about 15 weight percent.
The grafted linear ethylene polymer
(e.g., grafted linear HDPE) and the ungrafted linear
ethylene polymer (such as ungrafted LLDPE) may be
blended together prior to extrusion, either by melt
blending or dry blending. Dry blending of pellets of
the grafted linear ethylene polvmer and the ungrafted
linear ethylene polymer prior to extrusion is generally
adequate where the melt indices of the blend components
are similar. and there will generally be no advantage in
melt blending such blend constituents prior to
extrusion. However. where melt blending may be desired,
as in the case of grafted linear HDPE and LLDPE or
dissimilar melt indices, melt blending may be
accomplished with conventional blending equipment, such
as, for example. mixing extruders, Brabender mixers,
Banbury mixers, roll mills and the like.
The high performance thermoplastic polymer
useful as such as the second component of the dyeable
thermoplastic bicomponent fiber of the present invention
can be a polyester (e.g., PET or PBT) or a polyamide
(e.g., nylon). The high performance thermoplastic
polymer can be used as one component of the bicomponent
fiber by contacting it with the grafted linear ethylene

W092/02669 2 V ~ 7 ~ ~ ~ PCT/US90/0~10
-13-

polymer(s) under thermally bonding conditions. such as
that encountered when coextruding bicomponent fiber
using a bicomponent staple fiber die. The high
performance polymer can either component of a
sheath/core configuration or it can be either component
of a side-by-side configuration. The high performanc
thermoplastic polymer can be chosen to provide stiffness
in the bicomponent fiber, especially when the grafted
linear ethylene polvmer is a polymer blenà of grafted
linear HDPE blended with ungrafted LLDP~. Additionallv.
the high performance thermopiastic polymer used in
making the bicomponent fiber cf the present invention
can be the same polymer as that used for making high
performance fiber which is blended with the bicomponent
fiber.
Extrusion of the poiymer through a die to form
a fiber is effected using con~entiona' eauipment such
as. for example. extruders. gear pumps and the like. It
2C is preferred to employ separate extruders. which feed
gear pumcs to supplv the separate molten polymer streams
to the die. The grafted linear ethylena polvmer or
polymer blend is preferablv mixed in a mixing zone of
the extruder and/or in a statlc mixer. for example.
upstream of the gezr pump in order to obtain a more
; uniform dispersion of the polymer components.
- Following extrusion through the die. the fiber
is taken up in solid form on a godet or another take-up
3 surface. In a bicomponent staple fiber forming process.
the fibers are taken up on a godet which draws down the
fibers in proportion to ~he speed of the tak,e-up godet.
In the spunbond process. the fibers are collected in a
jet, such as, for example. an air gun, and blown onto a
take-up surface such as a roller or moving belt. In the

.

~a~
WOg2/02669 PCT/US90/04410
-14-

melt blown process, air is ejected at the surface of the
spinnerette which serves to simultaneously draw down and
cool the fibers as they are deposited on a take-up
surface in the path of the cooling air. Regardless of
the type of melt spinning procedure which is used, it is
important that the fibers be partially melt drawn in a
molten state, i.e. before solidification occurs. At
least some drawdown is necessary in order to orient the
polymer ~olecules ~^or good tenacity. It is not
generally sufficient to sGlidify the fibers withou~
significant extension before take-u?. as ~;~^ fine
strands which are forme~ tnereby can hardly be colc
drawn. i.e. in a solid state below the melting
temFerature of the polvmer. because of the:r low
tenacity. On the other hand~ when the fibers are draws
down in the molten state. the resulting strands can mone
; readily be cold drawn because of the im?roved tenzcity
imparted by the melt drawing.
Melt drawdowns of up to about 1:1000 mav be
employed depending upon spinnerette die diameten and
spinning velocity. preferably from about 1:10 ~o about
1:200, and especially 1:20 to 1:10G.
Where the bicomponent staple-forming process is
employed. it may be desirable to cold draw the strands
with conventional drawing equipment. such as. for
example. sequential godets operating at differential
speeds. The strands may also be heat treated or
3 annealed by employing 5 heated godet. The strands may
further be texturized, such as. for example. by crimping
and cutting the strand or strands to form staple. In
the spun bonded or air jet processes, cold drawing of
the solidified strands and texturizing is effected in
the air~jet and by impact on the take-up surface,

2~ ~3v~
W092/02669 PCT/US9~/0~10
-15-

respectively. Similar texturizing is effected in the
melt blown process by the cooling fluid whicn is in
shear with the molten polymer strands. and which may
also randomly delinearize the fibers ?rior to their
solidification.
The bicomponent fibers so formed by the above-
described process also constitute a part of the present
invention. The bicomponent fibers are generally fine
denier filaments of 15 denier or less down to fractional
deniers. preferabiy in the range of rom l to 10 denier.
although this will depend on the desired properties of
the fibers and the specific application in which they
are to be used.
The bicomponent fibers of tne present invention
have a wide variety of potential applications. ~or
example. the bicomponent fibers may be formed into a
batt and heat treated by calendaring on a heated.
embossed roller to form a fabric. The batts may also be
heat bonded-, for example. by infrared light, ultrasound
or the like, to obtain a high loft fabric. The fibers
may also be empioyed in conventional textile processing
such as carding. sizing. weaving and the like. Woven
fabrics made from the bicomponent fibers of the present
invention may also be heat treated to alter the
properties of the resulting fabric.
A preferred embodiment of the invention resides
in the employment of the bicomponent fibers formed
according to the process of the invention in binder
fiber applications with high performance natural and~or
synthetic fibers such as, for example, polyamides~
polyesters, silk, cellulosics (e.g. cotton), wool.
modified cellulosics such as rayon and rayon acetate.

W092~02669 2 0 5 ~ 3 ~ 3 PCT/US90/0~10 '
-16-

and the like. The bicomponent fibers of the present
invention find particular advantage as binder fibers
owing to their adhesion to performance fibers and
dyeability thereof which is enhanced by the presence of
the acid groups in the grafted linear ethylene polymer
component and the relatively lower melting temperature
or range of the grafted iinear ethylene polymer
component relative to the performance fiber. The
relative proportions of tne binder fiDer of the present
invention employed in admixture with performance fibers
in a fiber blend wi;l depend on the desired application
and capabilities of the resulting fiber mixture and/or
fabric obtained thereby. It is preferred to employ from
about ~ to about g~ parts by weight of the binder fiber
per 100 parts by weight of the binder fiber/performance
fiber mixture, more preferably from about 5 to about 53
parts by weight binder fiber. and especia~ly 5 to 1
parts by weight binder fiber.
j 20 In preparing non-woven fabrics from the
bicomponent binder fiber/performance fiber blend of the
invention, there are several important considera~ions.
Wheré the binder fibers are in staple form~ there should
be no fusing of the fibers when they are cut into
staple, and the crimp imparted to the binder fibers
should be sufficient for blending with the performance
fibers to obtain good distribution of the fibers.
The ability of the component comprising at
3 least one grafted linear ethylene polymer having pendant
succinic acid or anhydride groups to adhere to the other
component of at least one high performance thermoplastic
polymer is an important consideration in cutting of
bicomponent staple fiber. When bicomponent staple fiber
is cut and one of the components (e.g., the core of a




'
' ` '''

2~7~
~'092/02669 PCT/US90/04410


bicomponent .'iber) protrudes from t;ne cuv e~ge~ the
.lber will creare ar. irrita~ion when worrl ne~ ~o the
skin. ThC irr.taticn is especially pronounced .Jnen the
^ore compor.ent is a :qioh performanc- thermopias~,~c such
2S PE.. 'when ungr~fted linear -thylene ?olymer and PET
are made. respectiveiv, into 3 sheath/core bicomponent
f.Der and cu~ into shor- sta?le fibcr. the core Gi' PET
2rctrrudes beyond the cu. edge. lhe er,nanced a~ir.es;on G'
t.qe graf~Qr 1 near e,.qyiQne ?oi~Jmer componen ~o ~he .-E.
c~mponer.~ _aed in makin the dyeaDle ther.rnop'las'lc
, ~,
_~comron-n~ ^ b-r o^ -'h- ?r-,en- inve-l or. rcr~c_a ?EI
pro~rusio-. D-~/on~ _in, fiDer' _fter cuttin, -r.d r,hus
-naDle, fabr~cs and 'i3er b'ends ,- ~e ~arQ ~.;h~C.^ can be
mor- comfort2bly wor.-. next to th_ s'r~in.
,,
~ he abl L_'y ^f ~r~e bicomponer.' bindc- bers ~c~
ad'r.erQ -o tr.- ?er,ormance iibers is anG~ncr im?cntant
cor.sider tion. Acr.esio.-. and ~yea~-`i r- c7n 3cn r~i~ y
controllec b-; varyiqO ~.^- acid CorltQr.t o- tne binscr
2~ .iber. e;.~her b. tne 'evel o.' gra.~ o. m-lelc -cid or
anhydrid_ in the gra ~-- linear _ :n~,~lene polymer. or b~-
tne prGpcr ior. o'` th- -r~fted _in-_r e'r.vien~ -.o'.ymer
~iende~ .!i'r. thQ ur.gr-:'~,ed lincar e~h~yierl_ ?oivmer i,.
~.he bico...-o:le-it 5indQ: i' Ders. r. .,ypic^l non-:~ovcn
2~ fabrlcs ob ain_d bf tr.erma"-J bond ng tr.- perforl,.ancc
:irers wi'h a bicomponerlt binaer f~'ber. the abilit~y ~f
'he binder fibers to 5Ond to-,ether tne ?erformance
ibers de?ends large'y on the thermal bon-lng o the
?erfor~ance ~ibers ~oge her r~y ~he ~incer fibera. In
tJpica_ pri^r ar~ r.on.-.~oven faDrlcs ei,.ploying binder
fibers. tr.- 5inder fiDer therca'ly Doncs performlance
fibers to~ether bj a, ieas~ ?ar r ia L iy me!ting ~o form
globules cr beads which encapsulate ~he ?erformance
fibers. Thne binder fibers of the present inven~ion

20~7~
W092/02669 PCT/US90/04410
-18-

enhance the non-woven fabric by providing great adhesion
of the binder fiber to the performance fiber. Employing
the binder fibers of the present invention. it is also
possible to obtain thermal bonding of the binder fiber
to a performance fiber by partial melting and contact
- 5 adhesion in which the bicomponent binder fibers largely
retain their fibrous form. and the resulting non-woverl
fabric is characterized 5y a reduced number of Olobules
or beads formed by the meiting of the iower melting
component of the bicomponent binder fibers.
-t is also importan~ for one componen~ OA th~
bicomponent binder fiber to have a relatively broad
melting point range or tnhermai Donding window.
particularly where hot calendaring is employed to obtain
a thermal bonding of a non-woven or woven fabric. A
good indication of meltina point range or thermai
bonding window is the dlfference between th- Vicat
softening point and the peak melting point determined by
dlfferential scanning calorime~ry (DSC). Narrow melting
point ranges present a difficu ~ target for process
bonding equipment such as a calendar roll. and even
slight variations in the temperature of bonding
equipment can result in an insufficient bond to be
formed betwee.n the bicomponent binder fibers ar.d the
performance fibers. If too low a temperature is
: ~ .
employed, the bicomponent binder-fibers will not
~sufficiently fuse. whereas when too high a temperature
is employed, one component of the bicomponent binder
fiber may completely melt and run right out of the
performance fiber batt. Thus. a broad melting point
range is desired in order that partial fusion of on-
component of the bicomponent binder fiber materia1 car.
be achieved without a complete melting. A melting point




.
:
'

~ W092/02669 ~ ~ 7 3 ~ g PCT/US90/04410
_ 1 9--

range of at least 7.5C is desired for proper thermal
bonding. and preferably a sufficiently broad melting
point range that a minimum 10C bonding window is
obtained.
Another important characteristic of bicomponent
binder fibers is that when they are melted in equipment-
such as a calendar roll, one of the components will have
a sufficient melt viscosity to be retained in the fiber
matrix and not readily flow therefrom. An important
advantage of the bicomponent binder fibers of the
preser.t invention is tha one component has generally
higher me:t viscosity than fibers consisting of
ungrafted LLDPE and/or ungrafted iinear HDPE. In
addition to using a calendar roll. bonding of the
present binder fibers can also be obtained using other
bonding techniques. e.g. with hot air. infrared heaters.
ard the like.
2~ The thermoplastic bicomponent fibers of the
invention can be dyed by contacting them with a water
soluble ionic dye. preferably a water soluble cationic
dye. in a suitable aqueous medlu~.. The aqueous medium
can contain surfactants, i; desired. to promote contact.

The invention is illustrated by way of, but not
limited to, the examples which follow.
EXAMPLE 1
3 A linear HDPE ethylene~propylene copolymer (the
"base" polymer), having a MI of about 25 grams/10
minutes and density of O.g55 g~cc. is extruded with
maleic anhydride (3.0 pounds per hour) and dicumyl
peroxide (0.3 pounds per hour) at an average melt
temperature of 225C (the temperature ranged from about

2~73~
w0~2/02669 PCT/US90/04410
-20-

180 to about 250C) using a Werner-Pfleiderer twin-screw
devolatization extruder. The final incorporated
concentration of maleic anhydride is about 110 by weight
(as determined by titration) and has a MI of about
- 16-18 grams/10 minutes: this is called the MAH-grafted
linear HDPE concentrate.
Using a 6-inch Farrell two-roll mill. 250 gram
sampies are blended ha~ing compositions ranging from ,%
MAH-grafted linear HDPE concentrate to 50~ MAH-grafted
linear HDPE concentrate in v2rious LLDPE resins 2t a
me't temperature of 170~ he ~lends are useful 2S 2'
least one component in 2 bicomponent fiber, wherein at
least one other component is a perîormance poiymer
component. such as PBT or PET.
ExamDle 2
Ten percent of a grafted linear HDPE
(ethylene/propylene copolymer. MI of 2~ grams,'10 mlnutes
before grafting. densitv of 0.955 g/cc before grafting)
having about 1% bv weight succinic acid groups is
biended with about 9C,~ by weight of an ungrafted LLDPE
(ethyleneioctene copolymer. MI of 18 grams/10 minutes.
0.930 g/cc density) to form a polymer blend having about
0.1~ by weight succinic acid groups. The polvmer blend
is then used as a sheath component in a bicomponent
staple fiber spinning operation. with the core component
being PET. The sheath/core bicomponent fibers are
blended with other performance fibers such as PET or
3 cellulosics, formed into batts and oven bonded. The
batts are found to be weIi-bonded and have good physical
integrity.

2~5i73~
W092/02669 PCT/US90/04410


Example 3
Linear HDPE (ethylene-propylene copolymer. MI
of 25 grams/10 minutes, 0.95~ gicc density) is grafted
with maleic acid to provide succinic acid groups along
the polymer chain. Portions of the grafted linear HDPE
are then blended with amounts of ungrafted LLDP~
(ethylene-octene copolvmer. MI of 18 grams,'10 minutes.
0.930 g/cc density) to produ^_ polymer blends containlng
o.o5aO. 0.1~. 0.157c. 0.2~. and 0.4% by weight of the
succinic acid. The grafted linear HDPEi'LLDPE polymer
bler.d samples are coextrud-a .with PE t~ ?roduce sid--
by-side bicomponent fibrous materia'. The adhesion
between fibers in a heat-Donded bat of the fibrous
material is appreciably better than that obtained in
comparison by using the same linear HDPE and LLDPE
without any grafted acid groups. The maximum heat-
bonded bat strength occurs when usinO bi~omponent fiber
having a succinic acid level of about 0.1~ by weigh~.
ExamDle 4
Linear HDPE (eth~lene-p.opylene copol~mer. Ml
of 25 grams/10 minutes. C.?,-,i g~cc densitv) is grafted
wlth male-c anhvdride ~o ?ro~.~d^ abou~ l~s DV weigh'
succinic anhydride groups aiong ths polymer chain.
Portions of the grafted linear HDP' are blended with
amounts of ungrafted LLDPE (e~hylene-octene copolymer.
MI of 18 grams/10 minutes. 0.930 gicc density) to
produce polymer blends containing 0.05~. 0.1~. 0.15~.
0.2%~ and 0.5% by weight of the succinic acid groups.
Polym~r blends of the grafted linear HDPE with the
ungrafted LLDPE can be coextruded as the sheath layer in
a bicomponer.t spunbond system using a PET as the cor-
layer. The resultant thermally bonded fabric has a
bonded fabric strength higher than that obtained using

W092/02669 RCT/US90/n4410
-~2-

ungrafted linear ethylene polymer alone as the sheath
resin.
Example 5
LLDPE (ethylene-octene copolymer. MI of 18
grams/lO minutes. O.93O g/cc density) does not accept
dye when treated with Basic Viole~ III (a basic dye also
known as Crystal ~ioiet~ at 80C for 15 minutes in the
presence of a dro? of didec~vi dimethyl ammonium chloriae
used as a wetting agen'. When blended wlth enough LLDPE
gra~ted w.tn maleic anhydride to providc a r,olvmer blend
having about 0.157O Dy weight succinic acid groups. the
resulting polymer blend. when treated in the same manner
as immediately above. became dyed to a biue,purpie
color. The dye does not readily leach out. even when
placed in boiling water for 10-15 minutes. Other water
soluble cationic dyes (i.e.. dyes which ane typically
referred to as "basic dyes" in the :ndustry` can be
similarly used to dye the novel bicomponent fibers.




3o

Representative Drawing

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Administrative Status

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Administrative Status

Title Date
Forecasted Issue Date Unavailable
(86) PCT Filing Date 1990-08-07
(87) PCT Publication Date 1992-02-20
(85) National Entry 1992-04-06
Examination Requested 1997-08-01
Dead Application 2001-12-14

Abandonment History

Abandonment Date Reason Reinstatement Date
2000-12-14 R30(2) - Failure to Respond
2001-08-07 FAILURE TO PAY APPLICATION MAINTENANCE FEE

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $0.00 1992-04-06
Maintenance Fee - Application - New Act 2 1992-08-07 $100.00 1992-04-06
Registration of a document - section 124 $0.00 1992-11-20
Registration of a document - section 124 $0.00 1992-11-20
Registration of a document - section 124 $0.00 1992-11-20
Registration of a document - section 124 $0.00 1992-11-20
Maintenance Fee - Application - New Act 3 1993-08-09 $100.00 1993-05-31
Maintenance Fee - Application - New Act 4 1994-08-08 $100.00 1994-05-26
Maintenance Fee - Application - New Act 5 1995-08-07 $150.00 1995-06-08
Maintenance Fee - Application - New Act 6 1996-08-07 $150.00 1996-05-31
Maintenance Fee - Application - New Act 7 1997-08-07 $150.00 1997-06-05
Request for Examination $400.00 1997-08-01
Maintenance Fee - Application - New Act 8 1998-08-07 $150.00 1998-06-03
Maintenance Fee - Application - New Act 9 1999-08-09 $150.00 1999-05-26
Maintenance Fee - Application - New Act 10 2000-08-07 $200.00 2000-06-20
Extension of Time $200.00 2000-10-16
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
THE DOW CHEMICAL COMPANY
THE DOW CHEMICAL COMPANY
Past Owners on Record
BIESER, JOHN O.
FINLAYSON, MALCOLM F.
LANCASTER, GERALD M.
TABOR, RICKY L.
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Claims 1999-11-15 3 83
Description 1999-11-15 22 833
Abstract 1995-08-17 1 68
Claims 1994-05-28 3 79
Description 1994-05-28 22 829
Cover Page 1994-05-28 1 14
Assignment 1992-04-06 12 377
Prosecution-Amendment 2000-06-14 2 81
Prosecution-Amendment 1999-05-13 2 4
Correspondence 2000-10-16 1 33
Correspondence 2000-11-20 1 2
Prosecution-Amendment 1999-11-15 5 183
PCT 1992-04-06 3 110
Prosecution-Amendment 1997-08-01 1 41
Fees 1995-06-08 1 83
Fees 1996-05-31 1 81
Fees 1992-04-06 1 39
Fees 1993-05-31 2 76
Fees 1994-05-26 1 67