BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to methods and apparatus for producing fibers and fabrics
in a closed fiber spinning system, where the fibers and fabrics include a plurality
of different polymer components.
Description of the Related Art
[0002] A number of closed fiber spinning systems are known in the art for manufacturing
spunbond fabrics having certain desirable characteristics. For example,
U.S. Patent Nos. 5,460,500,
5,503,784,
5,571,537,
5,766,646,
5,800,840,
5,814,349 and
5,820,888 all describe closed systems for producing spunbond webs of fibers. The disclosures
of these patents are incorporated herein by reference in their entireties. In a typical
closed system, filaments are spun, quenched and drawn in a common enclosed chamber
or environment, such that the air or gas stream that is utilized to quench the fibers
emerging from a spinneret is also utilized to draw and attenuate the fibers downstream
from the quenching stage.
[0003] In direct contrast to open fiber spinning systems (i.e., systems in which extruded
filaments are not spun, quenched and drawn in a common chamber or environment and
are typically exposed to the ambient environment during some or all of the fiber forming
steps), closed systems eliminate any interference from uncontrolled and potentially
detrimental air currents during fiber formation. In fact, a typical closed fiber spinning
system limits exposure of extruded filaments to only desirable air or gas currents
having selected temperatures during fiber formation, thus facilitating the production
of very delicate and uniform fibers having desirable deniers that are difficult to
obtain from a typical open fiber spinning system.
[0004] One important component in any fiber spinning system is the polymer delivery system,
typically referred to as the spin beam, which provides molten polymer streams at a
selected metering or flow rate to the fiber spinning system for extrusion into filaments
by a spinneret. One type of spin beam typically utilized and highly advantageous for
spinning fibers in a closed system is commonly referred to as a "coat hanger" spin
beam. This type of spin beam is typically formed by two sections, constructed of metal
or other suitable material, joined together in a fluid tight relationship at facing
or mating surfaces, where each mating surface has grooves etched into the surface
that correspond with and mirror grooves etched in the mating surface of the other
section. The grooves etched on each mating surface form a profile that resembles a
triangular "coat hanger" configuration.
[0005] An exploded view of a conventional "coat hanger" spin beam is illustrated in Fig.
1. Spin beam 2 includes two generally rectangular halves or sections 3 having a number
of electric heaters 12 disposed within each section to heat polymer fluid flowing
within the spin beam toward the spinneret. In operation, a molten polymer stream is
directed (e.g., via a pump) into an inlet portion 4 of the "coat hanger" channel profile
of spin beam 2 and travels into an upper portion of the triangular channel portion
6 of the "coat hanger" profile that is disposed below and in fluid communication with
inlet portion 4. The "coat hanger" channel defined by the inlet portion and the triangular
portion is formed by corresponding grooves disposed on the mating surfaces of the
two spin beam sections 3. Upon entering channel 6, the molten polymer stream splits
into the two diverging channel sections 7 of the triangular channel portion, where
the split streams continue to travel and then converge within a horizontal channel
section 8 disposed at a lower end of the "coat hanger" channel between the lower ends
of the diverging channel sections. The horizontal channel section also extends longitudinally
along a lower end of spin beam 2. Affixed at the lower end of the spin beam are a
screen filter and plate 9 and a spinneret 10 having a plurality of orifices disposed
along its longitudinal dimension. The screen filter, plate and spinneret also extend
longitudinally along the lower end of spin beam 2 and are aligned and in fluid communication
with horizontal channel section 8. Thus, the molten polymer stream traveling into
horizontal channel section 8 of the "coat hanger" channel proceeds to flow through
screen filter and support plate 9 to spinneret 10, where the polymer stream is then
extruded through the spinneret orifices to form a plurality of polymer filaments.
The "coat hanger" channel configuration is particularly advantageous because it is
simple in design and creates a substantially uniform pressure differential within
the channels, resulting in a uniform delivery of the polymer stream into the horizontal
channel portion of the "coat hanger" channel" and uniform extrusion of molten polymer
through the spinneret orifices.
[0006] While a closed fiber spinning system combined with a "coat hanger" spin beam is useful
for manufacturing certain polymer fibers having desirable uniformities and deniers,
the "coat hanger" spin beam encounters problems when two or more different polymer
components are utilized to produce more complex fibers and spunbond webs of fibers.
In particular, it is very difficult in a "coat hanger" closed system to process two
or more different polymer components having different melting temperatures when manufacturing
multicomponent fibers or fabrics containing multiple polymer components. For example,
a bicomponent fiber consisting of two polymer components with significantly different
melting points would be extremely difficult to produce utilizing a closed spinning
system with a "coat hanger" spin beam (e.g., by utilizing a double "coat hanger" spin
beam with "coat hanger" channels being arranged in a side-by-side manner), because
the "coat hanger" spin beam would tend to be maintained at substantially the same
temperature by the electrical heaters disposed in the spin beam sections. The difficulty
is further exacerbated when utilizing polymer components that must be maintained at
or very near their melting temperatures to avoid gelling or cross-linking of the polymers.
Moreover, while the "coat hanger" systems deliver a uniform molten polymer stream
to the spinneret, it is difficult to modify the metering of the molten polymer stream
through the "coat hanger" spin beam to the spin pack, which is an important feature
in manufacturing more complex types of fibers such as multicomponent fibers having
varying geometries and/or polymer component cross-sections. Thus, the flexibility
of "coat hanger" spin beams is very limited in enabling the manufacture of a wide
variety of different fibers and fabrics within a closed fiber spinning system.
[0007] Accordingly, there exists a need for producing a wide variety of fibers and fabrics
including two or more polymer components in a closed fiber spinning system and with
a spin beam capable of delivering molten polymer streams of two or more different
polymer components for fiber production within the closed system.
SUMMARY OF THE INVENTION
[0008] Therefore, in light of the above, and for other reasons that become apparent when
the invention is fully described, an object of the present invention is to provide
a closed fiber spinning system capable of producing a wide variety of single and multicomponent
fibers and fabrics including different polymer components and having a desired denier
and degree of uniformity.
[0009] Another object of the present invention is to provide a spin beam assembly for the
closed system that is capable of delivering molten polymer streams to the spinneret
of the closed system, where the molten polymer streams include at least two different
polymer components having different melting temperatures.
[0010] A further object of the present invention is to uniformly maintain the two different
polymer components at their substantially different melting temperatures within the
spin beam assembly during delivery of the molten polymer streams to the spinneret.
[0011] Yet another object of the present invention is to provide a plurality of metering
pumps to individually control the flow rate of different molten polymer fluid streams
for extrusion at the spinneret.
[0012] The aforesaid objects are achieved individually and in combination, and it is not
intended that the present invention be construed as requiring two or more of the objects
to be combined unless expressly required by the claims attached hereto.
[0013] In accordance with the present invention, the aforementioned difficulties associated
with forming fibers and fabrics having multiple polymer components in a closed system
is overcome by employing a closed fiber spinning system including a spin beam assembly
that is capable of supplying a plurality of molten polymer streams to a spinneret,
where at least two of the polymer streams contain different polymer components, to
form multicomponent fibers or fabrics including multiple polymer components that have
a suitable uniformity and denier. The spin beam includes a plurality of metering pumps
to independently control the flow rates of one or more polymer streams, as well as
at least two thermal control units that independently and uniformly heat the different
polymer components to their appropriate melting temperatures while maintaining thermal
segregation between the different polymer components.
[0014] The above and still further objects, features and advantages of the present invention
will become apparent upon consideration of the following definitions, descriptions
and descriptive figures of specific embodiments thereof wherein like reference numerals
in the various figures are utilized to designate like components. While these descriptions
go into specific details of the invention, it should be understood that variations
may and do exist and would be apparent to those skilled in the art based on the descriptions
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015]
Fig. 1 is an exploded view in perspective of a conventional "coat hanger" spin beam
for delivering molten polymer fluid to a spin pack in a closed system.
Fig. 2 is an elevational side view in partial section of an embodiment of the closed
fiber spinning system of the present invention.
Fig. 3 is a perspective view in partial section of an embodiment of the spin beam
assembly for the closed system of Fig. 1.
Figs. 4-8 are transverse cross-sectional views illustrating embodiments of different
groups of fibers that may be produced by a closed system of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The closed fiber spinning system of the present invention is described below with
reference to Figs. 2 and 3. The terms "closed system" and "closed fiber spinning system",
as used herein, refer to a fiber spinning system including an extrusion stage, a quenching
stage and a drawing stage, where an air or other gas stream that is utilized to quench
the fibers in the quenching stage is also utilized to draw and attenuate the fibers
in the drawing stage, and the extrusion, quenching and drawing stages are performed
in a common enclosed environment (e.g., a single chamber or a plurality of chambers
communicating with each other). The term "fiber" as used herein includes both fibers
of finite length, such as conventional staple fibers, as well as substantially continuous
structures, such as filaments, unless otherwise indicated. The terms "bicomponent
fiber" and "multicomponent fiber" refer to a fiber having at least two portions or
segments, where at least one of the segments comprises one polymer component, and
the remaining segments comprise another, different polymer component. The term "single
component fiber" refers to a fiber consisting of a single polymer component. The term
"mixed polymer fiber" refers to a fiber consisting of two or more different polymer
components mixed together to form a substantially uniform composition of the polymer
components within the formed fiber.
[0017] Fibers extruded in the closed system of the present invention can have virtually
any transverse cross-sectional shape, including, but not limited to: round, elliptical,
ribbon shaped, dog bone shaped, and multilobal cross-sectional shapes. The fibers
may comprise any one or combination of melt spinnable resins, including, but not limited
to: homopolymer, copolymers, terpolymers and blends thereof of: polyolefins, polyamides,
polyesters, polyactic acid, nylon, poly(trimethylene terephthalate), and elastomeric
polymers such as thermoplastic grade polyurethane. Suitable polyolefins include without
limitation polymers such as polyethylene (e.g., polyethylene terephthalate, low density
polyethylene, high density polyethylene, linear low density polyethylene), polypropylene
(isotactic polypropylene, syndiotactic polypropylene, and blends of isotactic polypropylene
and atactic polypropylene), poly-1-butene, poly-1-pentene, poly-1-hexene, poly-1-octene,
polybutadiene, poly-1,7,-octadiene, and poly-1,4,-hexadiene, and the like, as well
as copolymers, terpolymers and mixtures of thereof. In addition, the manufactured
fibers may have any selected ratio of polymer components within the fibers.
[0018] Referring to Fig. 2, a closed system 100 is depicted including a spin beam assembly
102 for delivering molten polymer streams to a spin pack 104, and an enclosed chamber
106 for forming and delivering extruded filaments 108 to a web-forming belt 116, thus
forming an nonwoven web of fibers 118. It is to be noted that the closed chamber design
depicted in Fig. 2 is provided for exemplary purposes only, and the present invention
is in no way limited to such design. For example, any number of enclosed chamber designs
may be utilized in practicing the present invention, including, without limitation,
the enclosed chamber designs of
U.S. Patent Nos. 5,460,500,
5,503,784,
5,571,537,
5,766,646,
5,800,840,
5,814,349 and
5,820,888. The spin beam assembly, spin pack, enclosed chamber and belt are constructed of
metal or any other suitable material to receive and process molten polymer fluid streams.
[0019] The spin beam assembly 102 provides a number of independently metered molten polymer
streams to spin pack 104 for extrusion and fiber formation within closed system 100.
Three separate and independent heating systems are provided in the spin beam assembly
as described below to independently heat two segregated polymer fluid streams flowing
into the spin beam assembly and the spin beam. Referring to Fig. 3, spin beam assembly
102 includes a generally rectangular and hollow frame 103 enclosing a pair of substantially
cylindrical and hollow distribution manifolds 122, 130 and a generally rectangular
spin beam 140. Each distribution manifold 122, 130 extends longitudinally along a
rear wall 150 of the frame, with manifold 130 suspended slightly above and aligned
substantially parallel with manifold 122. An inlet pipe 123 extends transversely from
a central location of manifold 122 and through the rear wall 150 of frame 103 to connect
with a polymer supply source (not shown). Similarly, another inlet pipe 131 extends
transversely from a central location of manifold 130 and through an upper rear wall
151 of the frame to connect with another polymer supply source (not shown). A portion
of each inlet pipe also extends within each manifold to connect with a polymer distribution
pipe disposed within the manifold as described below. Manifold 122 is sealed at one
end and connected to a heat medium supply conduit 124 at the other end, with conduit
124 extending through a side wall 152 of frame 103 and connecting to a heat medium
supply source (not shown). Manifold 130 is also sealed at an end corresponding to
the sealed end of manifold 122 and is connected at the other end to another heat medium
supply conduit 132 extending through the side wall 152 of the frame, where the supply
conduit 132 is also connected to a heat medium supply source (not shown). The manifolds
are slightly staggered in alignment with respect to each other, with the end of manifold
122 that is connected to conduit 124 being closer to the side wall 152 of the frame
than the corresponding end of manifold 130.
[0020] Disposed and extending longitudinally within each distribution manifold 122, 130
is a polymer distribution pipe that connects with the corresponding inlet pipe 123,
131 protruding into the manifold interior. Each manifold 122, 130 basically surrounds
and jackets the distribution pipe disposed therein, allowing a fluidic heat transfer
medium (e.g., Dowtherm) to be delivered by the respective supply conduit 124, 132
into the manifold so as to surround and transfer heat to polymer fluid disposed within
the distribution pipe. The manifolds and piping associated with the manifolds facilitate
independent and segregated heating of two different polymer components to different
temperatures within spin beam assembly 102. In accordance to the invention the manifold
design provides uniform heating of polymer fluid flowing inside each polymer distribution
pipe within each manifold by surrounding each distribution pipe with a heat medium
at a substantially uniform temperature. This heating feature is a significant improvement
over the electric heating design provided in the "coat hanger" style spin beam, because
the electrical heaters in the "coat hanger" spin beam may yield undesirable thermal
gradients within the spin beam sections.
[0021] Each distribution manifold 122, 130 further includes a set of six polymer transfer
pipes 126, 134 extending transversely and at approximately equal longitudinally spaced
locations from the manifold toward a front wall 153 of frame 103, where transfer pipes
126 (which extend from manifold 122) are substantially parallel with transfer pipes
134 (which extend from manifold 130). 'Each transfer pipe 126, 134 also extends into
its respective manifold 122, 130 and connects at an appropriate location with the
corresponding distribution pipe disposed therein. Due to the vertical offset between
manifold 122 and manifold 130 within the frame of the spin beam assembly, transfer
pipes 134 are immediately routed vertically downward toward manifold 122 upon emerging
from manifold 130 so as to become substantially vertically aligned with transfer pipes
126 as they extend toward the front wall 153 of the frame. One skilled in the art
will recognize that each distribution pipe and the transfer pipes connecting to each
distribution pipe within each manifold can be independently designed to ensure a suitable
residence time of polymer fluid traveling through the distribution pipe and being
heated within the manifold. Further, the lengths of each of the transfer pipes extending
from a particular distribution pipe are preferably equal to ensure the residence times
of the fluid streams traveling within those transfer pipes is substantially the same.
[0022] Spin beam 140 is disposed longitudinally near the front wall 153 within frame 103.
The spin beam houses a set of six generally rectangular pump blocks 142 longitudinally
spaced along the spin beam to correspond with a single transfer pipe 126, 134 extending
from each manifold 122, 130 toward the pump blocks. Each pump block 142 includes a
first metering pump 128 that connects with a corresponding polymer transfer pipe 126
extending toward that pump block and a second metering pump 136 that connects with
a corresponding polymer transfer pipe 134 extending toward that pump block. The transfer
pipes 126, 134 extend through a rear wall of spin beam 140 to connect with their corresponding
metering pumps 128, 136. A heat supply conduit 144 extends from a lower portion of
the rear wall of the spin beam and through the frame side wall 152 to connect with
a fluid heat transfer medium supply source (not shown). The spin beam is heated by
heat transfer fluid medium supplied by conduit 144, which in turn heats and maintains
pump blocks 142 and pumps 128, 136 at a suitable temperature during operation of the
spin assembly. The pump blocks are further constructed of a material having a low
thermal conductivity to control or limit the amount of heat transferred between the
pump blocks, pumps and polymer fluid traveling through the pumps. For example, in
fiber manufacturing processes where two different polymer components are utilized
having different melting temperatures, the pump blocks are heated to the higher temperature
melting point. However, the polymer component with the lower melting temperature will
never achieve the higher temperature due to the limited heat transfer capacity of
the pump block.
[0023] Each metering pump 128, 136 further includes an inlet for receiving polymer fluid
from a corresponding polymer transfer pipe 126, 134 and multiple outlets for feeding
polymer fluid streams at a selected flow rate to inlet channels in spin pack 104.
In a preferred embodiment, each metering pump includes four outlets, such that the
spin beam assembly is capable of providing two sets of twenty four polymer fluid streams,
with the temperature and flow rate of each set being controlled independent of the
other. Such an embodiment could, for example, provide metered polymer streams from
each set about every six inches along a spin beam having a length of about twelve
feet. However, it is noted that the metering pumps may include any number of suitable
outlets depending upon the number of polymer streams required to be transferred to
the spin pack.
[0024] Spin pack 104 includes a plurality of inlet channels for receiving polymer fluid
streams from the spin beam assembly, a polymer filtration system, distribution systems
and a spinneret with an array of spinning orifices for extruding polymer filaments
therethrough. For example, the spinneret orifices may be arranged in a substantially
horizontal, rectangular array, typically from 1000 to 5000 per meter of length of
the spinneret. As used herein, the term "spinneret" refers to the lower most portion
of the spin pack that delivers the molten polymer to and through orifices for extrusion
into enclosed chamber 106. The spinneret can be implemented with holes drilled or
etched through a plate or any other structure capable of issuing the required fiber
streams. The spin pack basically coordinates molten polymer fluid flow from the spin
beam to form a desired type of fiber (e.g., multicomponent fibers, fibers having a
particular cross-sectional geometric configuration, etc.) as well as a desired number
of fibers that are continuously extruded by the system. For example, the spin pack
may include channels that combine two or more different polymer fluid streams fed
from the spin beam prior to extrusion through the spinneret orifices. Additionally,
the spinneret orifices may include a variety of different shapes (e.g., round, square,
oval, keyhole shaped, etc.), resulting in varying types of resultant fiber cross-sectional
geometries. An exemplary spin pack for use with system 100 is described in
U.S. Patent No. 5,162,074 to Hills, the disclosure of which is incorporated herein by reference in its entirety. However,
it is noted that any conventional or other spin pack for spinning fibers may be utilized
with system 100.
[0025] Enclosed chamber 106 includes a quenching station 110 disposed directly below spin
pack 104 and a drawing station 112 disposed directly below the quenching station.
A pair of conduits 114 are also connected at opposing surfaces of chamber 106 in the
vicinity of quenching station 110. Each conduit 114 directs a stream of air (generally
indicated by the arrows in Fig. 2) in a opposing direction from each other and toward
extruded filaments 108 exiting spin pack 104 and traveling through quenching station
110. The extruded filaments are thus quenched by the converging air streams from conduits
114 at the quenching station. The air streams are preferably directed in a direction
generally perpendicular to filaments 108 or slightly angled in a direction toward
drawing station 112, which is disposed below the quenching station. However, it is
noted that any number of air currents (e.g., a single air current) may be directed
in any suitable orientation toward the extruded filaments disposed in the quenching
station. It is further noted that any suitable gas other than air may be utilized
to quench the filaments at the quenching station. Further, depending upon the types
of polymer components utilized and the types of fibers to be formed, one or more controlled
vapor or gas treatment streams may also be employed to chemically treat the extruded
filaments within closed chamber 106 at quenching station 110 or at any other suitable
location.
[0026] Chamber 106 preferably has a venturi profile at drawing station 112, where the chamber
walls constrict to form a tapered or narrowed chamber section within the drawing station
to facilitate an increased flow rate of the combined air streams passing therethrough.
The increased flow rate of the air streams within the drawing station provides a suitable
drawing force to stretch and attenuate the filaments. Drawing station 112 extends
to an exit opening in chamber 106 that is separated a suitable laydown distance from
web-forming belt 116.
[0027] Web-forming belt 116 is preferably a continuous screen belt through which air can
pass, such as a Fourdrinier wire belt. Fibers exiting enclosed chamber 106 are laid
down on the belt to form a nonwoven web. The belt is driven, e.g., by rollers or any
other suitable drive mechanism, to deliver the web of fibers to one or more additional
processing stations. Disposed beneath belt 116 and in line with the exit opening of
chamber 106 is a recirculation chamber 120. The recirculation chamber includes a blower
(not shown) that develops a negative pressure or suction within chamber 106 to direct
the combined air streams from quenching station 110 through drawing station 112 and
into the recirculation chamber (generally indicated by the arrows in Fig. 2). The
air streams drawn into chamber 120 are recycled and delivered back to conduits 114
for redelivery into quenching station 110. Preferably, the recycled air streams are
also directed through a heat exchanger and/or combined with fresh air so as to maintain
a suitable temperature for the quenching air before being recirculated into quenching
station 110. In an alternative embodiment, the closed system may not employ recycled
air streams. Rather, a blower may continuously direct fresh air streams into and through
enclosed chamber 106, with the air dissipating out of the closed system upon emerging
from the drawing station rather than being recycled for further use.
[0028] Operation of closed system 100 is described below utilizing an exemplary bicomponent
fiber spinning process, where polymer components A and B are fed to the spin beam
assembly for forming the bicomponent fibers. It is to be noted, however, that system
100 may produce a wide variety of fibers, including single component and multicomponent
fibers. A molten stream of polymer A is delivered to spin beam assembly 102 via inlet
pipe 123, where it enters the polymer distribution pipe disposed within distribution
manifold 122. Simultaneously, a molten stream of polymer B is delivered to the spin
beam assembly via inlet pipe 131, where it enters the polymer distribution pipe disposed
within distribution manifold 130. A fluid heat transfer medium, supplied by conduits
124, 132, is provided within both manifolds to surround the distribution pipes disposed
therein and to uniformly and independently heat and/or maintain each of polymers A
and B at a suitable temperature.
[0029] The polymer A stream travels through the distribution pipe in manifold 122 and enters
polymer transfer pipes 126, which carry polymer A to the set of six metering pumps
128 disposed on pump blocks 142 in spin beam 140. Similarly, the polymer B stream
travels through the distribution pipe in manifold 130 and enters polymer transfer
pipes 134, which carry polymer B to the set of six metering pumps 136 disposed on
the pump blocks in the spin beam. Metering pumps 128 establish a suitable flow rate
for transferring a plurality of streams (e.g., twenty four) of polymer A to correspondingly
aligned inlet channels disposed on spin pack 104, while metering pumps 136 establish
a suitable flow rate (which is independent of the flow rate established for the polymer
A streams) for transferring a plurality of streams of polymer B to correspondingly
aligned inlet channels disposed on the spin pack.
[0030] The independently metered sets of molten polymer A and B streams are directed through
channels in spin pack 104 and through the spinneret to form bicomponent polymer fibers
consisting of those two polymers. The type of bicomponent fiber formed (e.g., side-by-side,
sheath/core, "islands in the sea", etc.) is established by the spin pack design, where
separated streams of polymers A and B are combined in a suitable manner upon emerging
from the spinneret. Additionally, a suitable cross-sectional geometry for the extruded
filaments may also be established by, e.g., providing spinneret orifices of one or
more selected geometries.
[0031] Filaments 108 consisting of polymers A and B are extruded through the spinneret and
enter quenching station 110 of enclosed chamber 106, where the filaments are exposed
to quenching air streams directed at the filaments from conduits 114. The blower in
recirculation chamber 120 creates a suction within the enclosed chamber that directs
the air streams through quenching station 110 and into drawing station 112, where
the velocity of the air streams is increased due to the constricted profile within
a portion of the drawing station. The extruded filaments are also directed downward
with the air streams from the quenching station into the drawing station, at which
point the filaments are drawn and attenuated in the drawing station. The drawn fibers
continue through enclosed chamber 106 to exit and form a nonwoven web 118 of fibers
on belt 116. The web of fibers are carried away by belt 116 for further processing.
Air streams traveling through and exiting enclosed chamber 120 are drawn into recirculating
chamber 120, where the streams are ultimately directed back into conduits 114 and
toward quenching station 110.
[0032] The combined features of temperature segregation and independent delivery of multiple
metered streams of molten polymer fluids within the spin beam in the closed system
of the present invention facilitates the production of a widely diverse range of fibers
and fabrics not previously achieved or even considered in conventional closed systems.
For example, providing independent and substantially uniform temperature control within
different molten polymer streams in the spin beam vastly increases the number of different
polymer combinations and ratios that can be achieved in individual fibers during fiber
formation. An even spinneret temperature profile may be maintained in the system without
forcing temperature changes in the polymer streams, which is not practical in the
electrically heated, "coat hanger" spin beam. The uniform temperature control provided
by the spin beam of the present invention, which eliminates potential thermal gradients
during heating, is far superior to the electrically heated, "coat hanger" spin beams
typically utilized in closed systems.
[0033] The independent control of different polymer component supply pressures via the separated
sets of metering pumps offers greater flexibility of polymer selection and distribution
for any given machine configuration by providing enhanced control for even delivery
of polymer over the entire machine width. The residence time can be more precisely
controlled with the spin beam assembly and spin pack of the present invention as compared
to the "coat hanger" system, a particularly important feature for heat sensitive polymers
requiring a reduced residence time. In particular, short residence times may be established
in the closed system of the present invention to minimize heat transfer between polymer
streams and the spin beam assembly and spin pack equipment.
[0034] The improved draw uniformity and prevention of external air flow or temperature disturbances
that a closed system provides further enhances the string-up and production of certain
types of sensitive multicomponent fibers. Additionally, the closed system facilitates
the spinning of certain multicomponent fibers into a controlled vapor or gas atmosphere
for chemical treatment of filaments formed during spinning, while easily containing
the vapors in the closed system. The spin beam assembly and spin pack also increases
the spinneret orifice density and possible orifice configurations in comparison to
the "coat hanger" spin beam (which only produces a linear or narrow array of extruded
filaments from the spinneret) to increase productivity and multiple polymer component
products manufactured in a single closed system. Further, the multi-stream metering
spin beam combined with the closed system of the present invention facilitates the
production of high value fabrics including, but not limited to, anti-stat fabrics,
skin wellness fabrics, wettability and abrasion resistance fabrics, and fabrics formed
by differential bonding methods (rather than conventionally used heat embossing).
Multiple fabric products may also be continuously produced by a single closed system
of the invention by, e.g., varying the types and grouping of fibers being extruded
in the cross machine direction of the system.
[0035] Some examples of polymer fibers that can be produced according to the present invention
are illustrated in Figs. 4-8. Fig. 4 depicts a single, low percent sheath/core fiber
202 formed among a group of single component or homopolymer fibers 204 to introduce
a high value, low melt strength, temperature and residence time sensitive additive
into a high quality web formed by the fibers.
[0036] Fig. 5 depicts a group of tri-component sheathed side-by-side fibers 302. These fibers
exhibit both of the side-by-side and sheath/core benefits in one web formed by the
fibers with the system of the present invention. In certain quench sensitive polymer
combinations, or in combinations where a viscosity mismatch exists between polymer
components, the spin pack of system may be configured to deliver formed fibers for
optimal orientation relative to the quenching air to minimize negative effects associated
with bending or doglegging of extruded filaments from the spinneret and thus increase
processing hole density and overall productivity. Figs. 6a and 6b depict two different
arrangements of side-by-side bicomponent fiber configurations, where the fibers 402,
502 of each configuration are oriented differently with respect to a dual air quench
system (direction of quenching air in Figs. 6a and 6b is depicted by arrows). Fig.
7 depicts yet another grouping of fibers that may be produced by the system of the
present invention, where dedicated metering techniques are utilized for producing
bicomponent sheath/core fibers 602 mixed with single component fibers 604. In still
another embodiment, the spin beam and spin pack of the present invention may be designed
to deliver exact mixed fiber sizes through multi-stream dedicated metering so as to
produce fabrics with tailored pore-size gradients. Fig. 8 depicts a grouping of fibers
that would produce such as a fabric, where larger diameter fibers 702 are combined
with smaller diameter fibers 704 during the closed system fiber spinning process.
[0037] Other examples of fibers that may be formed utilizing the system of the present invention
are sheath/core fibers where the sheath is a thermoplastic material with a low melting
point and the core material is a thermoplastic material with high strength characteristics.
A spunbond web of these fibers can be bonded thermally (e.g., using calendar rolls,
through-air, etc.) at temperatures high enough to soften or melt the outer sheath
material but low enough so as not to compromise the strength characteristics of the
core material. Such fibers can also have special properties available in the sheath
such as soft hand, anti-microbial capabilities, and gamma stability. Splittable fibers
can also be formed in which two or more separate polymer components in extruded filaments
are separated after formation of a web thus creating a web of finer fibers. Additionally,
side-by-side fibers can be formed that spontaneously crimp and bulk when subjected
to appropriate treatment. Mixed polymer fibers may also be formed in the closed system
of the present invention to provide a number of useful properties for final products
manufactured utilizing those fibers.
[0038] From the foregoing examples, it can be seen that the closed system of the present
invention is extremely versatile and facilitates the production of a wide variety
of multiple polymer component fiber and fabric combinations in a single system.
[0039] The present invention is not limited to the particular embodiments described above,
and additional or modified processing techniques are considered to be within the scope
of the invention. As previously noted, the present invention is not limited to the
closed chamber configuration of Fig. 2; rather, the closed system of the present invention
may utilize any closed environment configuration that prevents exposure of the extruded
filaments to uncontrolled temperatures and air currents during fiber formation.
[0040] Similarly, the spin beam assembly is not limited to the configuration of Fig. 3;
rather, the spin beam assembly may be designed to receive and thermally process and
meter any number of segregated polymer fluid supply streams. In other words, the spin
beam assembly may include any suitable number of polymer supply inlets connecting
to any suitable number of distribution pipes within distribution manifolds to independently
heat and/or maintain any number of different polymer streams at a variety of different
temperatures. The spin beam assembly may further include any suitable number of metering
pumps, where each pump has any suitable number of outlet streams, to independently
provide different polymer fluid streams at varying flow rates to the spin pack. Further,
each of the metering pumps may be configured to deliver one or more polymer fluid
streams to the spin pack at a flow rate independent of the flow rates for streams
metered by any of the other metering pumps.
[0041] The spin pack may be designed in any suitable manner to facilitate the production
of fibers and fabrics including any combination of single component or multicomponent
fibers of any suitable cross-sectional geometries. Further, any number or combination
of fiber processing techniques, yarn forming techniques, and woven and non-woven fabric
formation processes can be applied to the fibers formed in accordance with the present
invention.
[0042] Having described preferred embodiments of a new and improved closed system for producing
fibers and fabrics having multiple polymer components, it is believed that other modifications,
variations and changes will be suggested to those skilled in the art in view of the
teachings set forth herein. It is therefore to be understood that all such variations,
modifications and changes are believed to fall within the scope of the present invention
as defined by the appended claims. Although specific terms are employed herein, they
are used in a generic and descriptive sense only and not for purposes of limitation.
1. A system for manufacturing a non-woven web of fibers comprising:
a spin beam assembly configured to process and deliver a plurality of polymer streams
for extrusion through spinneret orifices, the spin beam assembly including a plurality
of delivery passages in fluid communication with the spinneret orifices, wherein at
least two of the delivery passages are configured to deliver separate polymer streams
of different polymer components to the spinneret orifices;
wherein the spin beam assembly includes a plurality of manifolds to segregate and
independently maintain the polymer streams of different polymer components at different
temperatures,
wherein each manifold provides uniform heating of a polymer stream flowing inside
a polymer distribution pipe within each manifold by surrounding each distribution
pipe with a heat transfer medium at a substantially uniform temperature,
a quenching chamber configured to receive and quench extruded filaments from the spinneret
orifices, the quenching chamber including a gas supply source to direct a gas stream
at the extruded filaments;
a drawing chamber in communication with the quenching chamber and configured to receive
and attenuate the quenched filaments; and
a forming surface configured to receive drawn filaments emerging from the drawing
chamber and form a non-woven fibrous web on the forming surface;
wherein the system maintains the extruded filaments in an enclosed environment between
the spinneret orifices and the drawing chamber to prevent uncontrolled gas currents
from contacting the filaments.
2. The system of claim 1, wherein the spin beam assembly includes a plurality of metering
pumps configured to independently deliver polymer streams of different polymer components
at varying flow rates to the spinneret orifices.
3. The system of claim 1, wherein the system is configured to produce arrays of multicomponent
fibers.
4. The system of claim 1, wherein the system is configured to produce arrays of bicomponent
fibers.
5. The system of claim 1, wherein the system is configured to produce arrays of single
component fibers, wherein at least one single component fiber consists of a polymer
component that is different from a polymer component of at least one other single
component fiber.
6. In a system for manufacturing fibers including a spin beam assembly, and a quenching
chamber in communication with a drawing chamber, wherein the system maintains an enclosed
environment between the spin beam assembly, the quenching chamber and the drawing
chamber to prevent uncontrolled gas currents from entering the enclosed environment,
a method of forming a non-woven web of fibers comprising:
(a) delivering a plurality of polymer streams from the spin beam assembly to spinneret
orifices, wherein at least two of the polymer streams include differing polymer components;
wherein the spin beam assembly includes a plurality of manifolds to segregate and
independently maintain the polymer streams of different polymer components at different
temperatures and wherein each manifold provides uniform heating of a polymer stream
flowing inside a polymer distribution pipe within each manifold by surrounding each
distribution pipe with a heat transfer medium at a substantially uniform temperature.
(b) extruding the plurality of polymer streams through the spinneret orifices to form
a plurality of filaments;
(c) quenching the extruded filaments by contacting the filaments with a gas stream
in the quenching chamber;
(d) drawing the quenched filaments in the drawing chamber; and
(e) depositing the drawn filaments onto a forming surface to form a non-woven fibrous
web on the forming surface.
7. The method of claim 6, wherein step (a) includes:
(a.1) delivering segregated polymer streams at varying flow rates to the spinneret
orifices.
8. The method of claim 6, further comprising:
(f) forming an array of multicomponent fibers.
9. The method of claim 6, further comprising:
(f) forming an array of bicomponent fibers.
10. The method of claim 6, further comprising:
(f) forming an array of single component fibers, wherein at least one single component
fiber consists of a polymer component that is different from a polymer component of
at least one other single component fiber.
1. System zur Herstellung einer Vliesbahn aus Fasern, Folgendes umfassend:
eine Spinnbalkenanordnung, die dafür gestaltet ist, mehrere Polymerströme für die
Extrusion durch Spinndüsenöffnungen zu verarbeiten und zuzuführen, wobei die Spinnbalkenanordnung
mehrere Zufuhrdurchlässe beinhaltet, die in Fluidverbindung mit den Spinndüsenöffnungen
stehen, wobei mindestens zwei der Zufuhrdurchlässe dafür gestaltet sind, separate
Polymerströme aus unterschiedlichen Polymerkomponenten zu den Spinndüsenöffnungen
zu führen,
wobei die Spinnbalkenanordnung mehrere Düsenkanäle beinhaltet, um die Polymerströme
aus unterschiedlichen Polymerkomponenten zu trennen und unabhängig voneinander bei
unterschiedlichen Temperaturen zu halten,
wobei jeder Düsenkanal eine gleichmäßige Erwärmung eines Polymerstromes bereitstellt,
der im Inneren einer Polymerverteilungsleitung in jedem Düsenkanal strömt, indem jede
Verteilungsleitung von einem Wärmeübertragungsmedium mit einer im Wesentlichen gleichmäßigen
Temperatur umgeben ist,
eine Abschreckkammer, die dafür gestaltet ist, von den Spinndüsenöffnungen extrudierte
Filamente aufzunehmen und abzuschrecken, wobei die Abschreckkammer eine Gaszufuhrquelle
beinhaltet, um einen Gasstrom auf die extrudierten Filamente zu richten,
eine Zugkammer in Verbindung mit der Abschreckkammer und dafür gestaltet, die abgeschreckten
Filamente aufzunehmen und dünner zu machen, und
eine Bahnbildungsfläche, die dafür gestaltet ist, gezogene Filamente,
welche die Zugkammer verlassen, aufzunehmen und auf der Bahnbildungsfläche eine Vliesfaserbahn
zu bilden,
wobei das System die extrudierten Filamente zwischen den Spinndüsenöffnungen und der
Zugkammer in einer geschlossenen Umgebung hält,
um zu verhindern, dass unkontrollierte Gasströme mit den Filamenten in Berührung kommen.
2. System nach Anspruch 1, wobei die Spinnbalkenanordnung mehrere Dosierpumpen beinhaltet,
die dafür gestaltet sind, unabhängig voneinander Polymerströme aus unterschiedlichen
Polymerkomponenten mit variierenden Strömungsraten zu den Spinndüsenöffnungen zu führen.
3. System nach Anspruch 1, wobei das System dafür gestaltet ist, Felder aus Multikomponentenfasern
zu erzeugen.
4. System nach Anspruch 1, wobei das System dafür gestaltet ist, Felder aus Zweikomponentenfasern
zu erzeugen.
5. System nach Anspruch 1, wobei das System dafür gestaltet ist, Felder aus Monokomponentenfasern
zu erzeugen, wobei mindestens eine Monokomponentenfaser aus einer Polymerkomponente
besteht, die sich von der Polymerkomponente mindestens einer weiteren Monokomponentenfaser
unterscheidet.
6. Verfahren zum Bilden einer Vliesbahn aus Fasern in einem System zur Herstellung von
Fasern, das eine Spinnbalkenanordnung und eine Abschreckkammer in Verbindung mit einer
Zugkammer beinhaltet, wobei das System zwischen der Spinnbalkenanordnung, der Abschreckkammer
und der Zugkammer eine geschlossene Umgebung aufrechterhält, um zu verhindern, dass
unkontrollierte Gasströme in die geschlossene Umgebung eindringen, wobei das Verfahren
Folgendes umfasst:
(a) Führen mehrerer Polymerströme von der Spinnbalkenanordnung zu Spinndüsenöffnungen,
wobei mindestens zwei der Polymerströme verschiedene Polymerkomponenten beinhalten,
wobei die Spinnbalkenanordnung mehrere Düsenkanäle beinhaltet, um die Polymerströme
aus unterschiedlichen Polymerkomponenten zu trennen und unabhängig voneinander bei
unterschiedlichen Temperaturen zu halten, und wobei jeder Düsenkanal eine gleichmäßige
Erwärmung eines Polymerstromes bereitstellt, der im Inneren einer Polymerverteilungsleitung
in jedem Düsenkanal strömt, indem jede Verteilungsleitung von einem Wärmeübertragungsmedium
mit einer im Wesentlichen gleichmäßigen Temperatur umgeben ist,
(b) Extrudieren der mehreren Polymerströme durch die Spinndüsenöffnungen, um mehrere
Filamente zu bilden,
(c) Abschrecken der extrudierten Filamente durch In-Kontakt-Bringen der Filamente
mit einem Gasstrom in der Abschreckkammer,
(d) Ziehen der abgeschreckten Filamente in der Zugkammer und
(e) Ablagern der gezogenen Filamente auf einer Bahnbildungsfläche, um eine Vliesfaserbahn
auf der Bahnbildungsfläche zu bilden.
7. Verfahren nach Anspruch 6, wobei der Schritt (a) Folgendes beinhaltet:
(a1) Führen getrennter Polymerströme mit variierenden Strömungsraten zu den Spinndüsenöffnungen.
8. Verfahren nach Anspruch 6, ferner Folgendes umfassend:
(f) Bilden eines Feldes aus Multikomponentenfasern.
9. Verfahren nach Anspruch 6, ferner Folgendes umfassend:
(f) Bilden eines Feldes aus Zweikomponentenfasern.
10. Verfahren nach Anspruch 6, ferner Folgendes umfassend:
(f) Bilden eines Feldes aus Monokomponentenfasern, wobei mindestens eine Monokomponentenfaser
aus einer Polymerkomponente besteht, die sich von der Polymerkomponente mindestens
einer weiteren Monokomponentenfaser unterscheidet.
1. Système de fabrication d'une nappe non tissée de fibres, comprenant :
un ensemble de métier à filer conçu pour traiter et délivrer une pluralité de flux
de polymère pour extrusion à travers des orifices de filières, l'ensemble de métier
à filer incluant une pluralité de passages de délivrance en communication de fluide
avec les orifices de filières, au moins deux des passages de délivrance étant conçus
pour délivrer des flux de polymère séparés à différents composants polymériques aux
orifices de filières ;
dans lequel l'ensemble de métier à filer inclut une pluralité de répartiteurs pour
séparer et maintenir indépendamment les flux de polymère de différents composants
polymériques à des températures différentes,
dans lequel chaque répartiteur assure un chauffage uniforme d'un flux de polymère
s'écoulant dans un tuyau de distribution de polymère dans chaque répartiteur en entourant
chaque tuyau de distribution d'un fluide de transfert thermique à une température
sensiblement uniforme,
une chambre de trempage conçue pour recevoir et tremper des filaments extrudés provenant
des orifices de filière, la chambre de trempage comprenant une source de fourniture
de gaz pour diriger un flux gazeux au niveau des filaments extrudés ;
une chambre d'étirage en communication avec la chambre de trempage et conçue pour
recevoir et adoucir les filaments trempés ; et
une surface de formage conçue pour recevoir les filaments étirés émergeant de la chambre
d'étirage et former une nappe fibreuse non tissée sur la surface de formage ;
le système maintenant les filaments extrudés dans un environnement clos entre les
orifices de filières et la chambre d'étirage pour empêcher des flux gazeux incontrôlés
de toucher les filaments.
2. Système selon la revendication 1, dans lequel l'ensemble de métier à filer comprend
une pluralité de pompes de dosage conçues pour délivrer indépendamment des flux de
polymère à différents composants polymériques à des débits variables vers les orifices
de filières.
3. Système selon la revendication 1, dans lequel le système est conçu pour produire des
réseaux de fibres multicomposants.
4. Système selon la revendication 1, dans lequel le système est conçu pour produire des
réseaux de fibres bicomposants.
5. Système selon la revendication 1, dans lequel le système est conçu pour produire des
réseaux de fibres monocomposants, au moins un composant fibreux monocomposant étant
composé d'un composant polymérique différent d'un composant polymérique d'au moins
un autre composant fibreux monocomposant.
6. Dans un système de fabrication de fibres comprenant un ensemble de métier à filer
et une chambre de trempage en communication avec une chambre d'étirage, le système
maintenant un environnement clos entre l'ensemble de métier à filer, la chambre de
trempage et la chambre d'étirage pour empêcher des flux gazeux incontrôlés de rentrer
dans l'environnement clos, procédé de formage d'une nappe non tissée de fibres comprenant
:
(a) la délivrance d'une pluralité de flux de polymère depuis l'ensemble de métier
à filer vers des orifices de filières, au moins deux des flux de polymère comprenant
des composants polymériques différents, l'ensemble de métier à filer incluant une
pluralité de répartiteurs pour séparer et maintenir indépendamment les flux de polymère
de différents composants polymériques à des températures différentes et chaque répartiteur
assurant un chauffage uniforme d'un flux de polymère s'écoulant dans un tuyau de distribution
de polymère dans chaque répartiteur en entourant chaque tuyau de distribution d'un
fluide de transfert thermique à une température sensiblement uniforme,
(b) l'extrusion de la pluralité de flux de polymère à travers les orifices de filières
pour former une pluralité de filaments ;
(c) le trempage des filaments extrudés en mettant les filaments en contact avec un
flux gazeux dans la chambre de trempage ;
(d) l'étirage des filaments trempés dans la chambre d'étirage ; et
(e) le dépôt des filaments trempés sur une surface de formage pour former une nappe
fibreuse non tissée sur la surface de formage.
7. Procédé selon la revendication 6, dans lequel l'étape (a) comprend :
(a.1) la délivrance de flux de polymères séparés à des débits variables aux orifices
de filières.
8. Procédé selon la revendication 6, comprenant en outre :
(f) le formage d'un réseau de fibres multicomposants.
9. Procédé selon la revendication 6, comprenant en outre :
(f) le formage d'un réseau de fibres bicomposants.
10. Procédé selon la revendication 6, comprenant en outre :
(f) le formage d'un réseau de fibres monocomposants, au moins une fibre monocomposant
consistant en un composant polymérique qui est différent d'un composant polymérique
d'au moins une autre fibre monocomposant.