Note: Descriptions are shown in the official language in which they were submitted.
1 2007488 F88-073A
METHOD OF PRODUCING A NO~O~N FIBROUS ~ uKED PANEL
AND PANEL PRODUCED THEREBY
Background of the Invention
In general, this invention relates to methods of
producing nonwoven fibrous panels having a textured outer
surface as well as fibrous panels produced by such
methods. More particularly, this invention relates to a
method for producing a nonwoven fibrous, flexible panel
having a textured outer surface that includes
needlepunching a needled web of at least interengaged
first fibers and second thermoplastic fibers to produce
the textured outer surface; and passing a fluid, at a
temperature sufficient to melt at least a portion of the
second thermoplastic fibers, through the web in a
direction from the textured outer surface to produce a
plurality of weld joints of the melted fibers; and it
relates to nonwoven fibrous panels produced by such
methods.
At present, nonwoven fabric interior linings and
floor mats for motor vehicles made up of nonwoven fabrics
having tufted surfaces to which a sintered thermoplastic,
latex, latex compound, or flexible urethane resin layer
must be applied to prevent fraying and to secure the tufts
in place, are known such as those disclosed in: Wishman
(U.S. Patent No. 4,320,167); the FIG. 6 embodiment of
Benedyk (U-S- Patent No. 4,258,094); Walters et al. (U.S.
Patent No. 4,581,272); DiGioia et al. (U.S. Patent No.
4,016,318); Hartmann et al. (U.S. Patent No. 4,169,176);
Sinclair et al. (U.S. Patent No. 4,186,230); Zuckerman et
al. (U.S. Patent No. 4,242,395); Morris (U.S. Patent No.
4,230,755); Robinson (U.S. Patent No. 3,953,632); Pole et
al. (U.S. Patent No. 4,199,634); and FIG. 3 of Miyagawa et
al. (U.S. Patent No. 4,298,643). Applying such a layer to
the nonwoven fabric substantially increases the cost to
2007~88
1 produce the interior linings and floor mats due to added
costs of (1) using, storing, and properly applying the
sintered thermoplastic, latex, latex compound, or urethane
layer, and (2) the complex manufacturing machinery and
added labor required to apply such a layer. Tufting is
the drawing of yarns through a fabric, either woven or
nonwoven, using a tufting machine. Tufting machines are
generally multineedle sewing machines which push the yarns
through a primary backing fabric that holds the yarns in
place to form loops as the needles are withdrawn. Tufting
requires that yarns separate from the woven or nonwoven
backing fabric be used to form the tufts; thus, tufting of
nonwoven fabrics to produce interior linings and floor
mats adds costs to manufacture such items.
Related patents, each of which discloses a
specifically-described nonwoven fabric heated in a
particular manner, are as follows: Street (U.S. Patent
No. 4,668,562); Sheard et al. (U.S. Patent No. 4,195,112);
Benedyk (as above '094); Erickson (U.S. Patent No.
4,342,813); Newton et al. (U.S. Patent No. 4,324,752);
Mason et al. (U.S. Patent No. 4,315,965); and Trask et al.
(U.S. Patent No. 4,780,359). In particular, the nonwoven
staple polymer fiber batt of Street (as above '562), also
known as a high-loft nonwoven fabric, is simultaneously
compressed substantially by vacuum and heated by p~lling
air at a temperature that will only make the polyester
soft and tacky, through the batt. FIGS. 2 and 9 of Street
('562) illustrate the change in thickness and density of
the batt before and after the disclosed Street process has
been performed on the batt. Such substantial batt
compression is undesirable in the fabrication of nonwoven
fabric interior linings and floor mats, or the like, which
generally have a decorative outer surface and must have
sufficient strength and thickness to withstand frequent
and harsh use.
It is a primary object of this invention to
provide a method for producing a nonwoven fibrous,
flexible panel retaining a "velour-like" textured outer
surface, which is capable of withstanding frequent and
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20~7488
1 harsh use without necessarily needing a backing layer of
sintered thermoplastic, latex, latex compound, urethane,
or the like. It is another object to produce a nonwoven
fibrous panel by such a method that is less costly to make
or has fewer different requisite components than known
nonwoven fabric products of similar nature.
Summary of the Invention
Briefly described, the invention includes a
method for producing a nonwoven fibrous, flexible panel
having a textured outer surface, comprising the steps
of: providing a needled web having a back surface, the
needled web comprised of interengaged first fibers and
second thermoplastic fibers; needlepunching the web to
produce the textured outer surface comprising at least a
portion of the first fibers and the second thermoplastic
fibers, the back surface located opposite the textured
outer surface; and passing a fluid, at a temperature
sufficient to melt at least a portion of the second
thermoplastic fibers, through the web in a direction from
the textured outer surface toward the back surface to
produce a plurality weld joints, the textured outer
surface thereafter being substantially free of the second
thermoplastic fibers. Another characterization of the
invention includes a method for producing a nonwoven
fibrous, flexible panel having a textured outer surface,
comprising the steps of: needlepunching a needled web to
produce the textured outer surface comprising at least a
portion of first fibers and second thermoplastic fibers, a
back surface of the web located opposite the textured
outer surface; and providing a pressure gradient across
the web to move air, at a temperature sufficient to melt
at least a portion of the second thermoplastic fibers
producing a plurality of weld joints thereof, in a
direction from the textured outer surface toward the back
surface, the textured outer surface being substantially
free of the weld joints. Also, the invention includes a
nonwoven fibrous panel produced by either characterization
~- of the method of the invention.
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2007488
-3a- 25145-214
According to a further aspect of the present invention
there is provided a nonwoven fibrous, flexible material comprising
a needled web having a front outer surface and a back surface
disposed opposite thereof and including interengaged first fibers
and second thermoplastic fibers which have been at least partially
melted, said outer surface being substantially free of said second
thermoplastic fibers and said web having a plurality of weld
joints between said melted second thermoplastic fibers and at
least a portion of said first fibers proximate said back surface.
In other embodiments: said weld joints comprise softened
and rehardened second thermoplastic fibers to provide a
concentration of said weld joints toward the back surface of said
web; said weld joints comprise completely melted and rehardened
second thermoplastic fibers; and said weld joints comprise second
thermoplastic fibers resulting from flow of softened second
thermoplastic fibers flow toward said back surface prior to
rehardening to concentrate said well joints toward said back
surface and to increase the interengagement between said
rehardened second thermoplastic fibers and said first fibers.
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2007488
l Brief Description of the Drawings
The invention in its preferred embodiments will
be more particularly described by reference to the
accompanying drawings, in which like numerals designate
like parts.
FIG. l is a block flow diagram of a preferred
method of the present invention.
FIG. 2 is a schematic drawing of an apparatus
capable of performing a preferred method of the present
invention, particularly illustrating material flow.
FIG. 3 is an end elevational view of an
apparatus capable of performing a preferred method of the
present invention.
FIG. 4 is an enlarged, partial sectional view
taken along 4-4 of FIG. 3 particularly illustrating the
direction of fluid flow through fluid recirculation
chamber 40 of the FIG. 3 apparatus.
FIG. 5 is an enlarged, pictorial partial
sectional view taken from FIG. 2 illustrating a preferred
nonwoven fibrous panel of the invention.
FIG. 6 is an enlarged, partial sectional view of
the heat drum of FIG. 2 illustrating pin ring 90 secured
around the circumference of heat drum 14.
Description of the Preferred Embodiments
The first block in the flow diagram of FIG. l
represents Needled Web Formation. A preferred nonwoven
needled web of the invention is a blend of at least a
first and second type of loose fiber interengaged and
consolidated together to form a coherent nonwoven fabric,
the second fiber type being a thermoplastic fiber. The
interengaging and consolidating may be accomplished by an
operation known in the art as needlepunching on a needle
loom having needles that punch into and withdraw from the
webbing at a desired number of strokes per minute; see
Adams et al. (U.S. Patent No. 4,424,250) for a more
detailed description of needlepunching. Several different
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2007~88
1 thermoplastic fibers are available for use as the second
thermoplastic type of fiber in the preferred nonwoven
needled web; these include, but are not limited to,
polyethylene, polypropylene, polyester, nylon,
polyphenylene sulfide, polyether sulfone, polyether-ether
ketone, vinyon, and bicomponent thermoplastic fibers.
Nylon fibers, as defined by the U.S. Federal Trade
Commission, are made from a manufactured substance which
is any long chain synthetic polyamide having recurring
amide groups (-NH-CO-) as an integral part of the polymer
chain; and include those nylon fibers derived from the
polyamide condensation product of hexamethylenediamine and
adipic acid (i.e. Nylon 6,6), as well as those derived
from the polycondensation of epsilon caprolactam (i.e.
Nylon 6). The Phillips Petroleum Company manufactures and
sells a suitable polyphenylene sulfide under the trademark
"Ryton". Vinyon fibers have been defined as fibers made
from a manufactured substance which is any long chain
synthetic polymer composed of at least 85% by weight of
vinyl chloride units. An example of a usable bicomponent
thermoplastic fiber is one made of a polypropylene core
and a polyethylene sheath. Chisso Corporation of Japan
manufactures a suitable bicomponent polyolefin fiber sold
as "Chisso ES" fiber.
The first type of fiber in the preferred
nonwoven needled web can be either (1) a non-thermoplastic
fiber or (2) a thermoplastic fiber having a temperature
melting point higher than that of the second thermoplastic
type of fiber used in the needled web. Suitable non-
thermoplastic fibers available for use as the first type
of fiber include, but are not limited to, wool, cotton,
acrylic, polybenzimidazole, aramid, rayon or other
cellulosic material, carbon, glass, and novoloid fibers.
Due to their very high temperature stability, for purposes
of the present invention polybenzimidazoles have been
characterized as non-thermoplastics. Polybenzimidazoles
are a class of linear polymers whose repeat unit contains
a benzimidazole moiety. PBI is the acronym commonly used
for the poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (1)
. .
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2ûG7488
1 that is commercially available from Celanese Corp.
(Charlotte, N.C.). Aramid fibers, as defined by the U.S.
Federal Trade Commission, are made from a manufactured
substance which is a long chain synthetic polyamide having
at least 85% of its amide linkages (-NH-CO-) attached
directly to two aromatic rings; and include those aramid
fibers derived from poly(m-phenyleneisophthalamide) such
as "Nomex" fibers (a registered trademark of E.I. du Pont
de Nemours & Co.), as well as those derived from poly(p-
phenyleneterephthalamide) such as "Kevlar" fibers (a
registered trademark of E.I. du Pont de Nemours & Co.).
Novoloid fibers have been defined as fibers made of a
manufactured substance which contains at least 85% by
weight of a cross-linked novolac. American Kynol, Inc., a
division of the Japanese corporation Nippon Kynol, sells a
suitable novoloid fiber under the registered trademark
"Kynol".
If the first type of fibers in the preferred
nonwoven needled web are thermoplastic, the thermoplastic
used must have a higher temperature melting point than the
temperature melting point of the second thermoplastic type
of fibers used in the web so that the second thermoplastic
type can be melted without melting the first type. If the
first type of fibers are thermoplastic, any of the
thermoplastics described above as being available for the
second type of fibers are also available for the first
type of fibers as long as the consideration stated
immediately above is met. If desired, the preferred
nonwoven needled web may have components in addition to
the above-described first and second type of fibers.
A preferred nonwoven needled web which has only
first and second type of fibers may have up to 20% of
second thermoplastic type fibers and correspondingly up to
80~ of first type fibers. By way of example, a nonwoven
needled web could have 13%-15~ polyethylene second type
fibers and, correspondingly, 87~-85% polypropylene first
type fibers. Other example combinations include: low
melt polyester copolymer second type fibers with polyester
first type fibers; polypropylene second type fibers with
~
2007488
1 polyester first type fibers; polyethylene second type
fibers with polyester first type fibers; and low melt
polyester second type fibers with polypropylene first type
fibers. First and second type fiber combinations are in
no way limited to these examples.
The second block in the flow diagram of FIG. 1
states "Needlepunching Web to Produce Textured Outer
Surface". A process known as structured needlepunching
(see apparatus 46 illustrated schematically in FIG. 2) may
be used to produce a "velour-like" textured outer surface
of the preferred nonwoven needled web. Such
needlepunching may involve the use of fork-end shaped
needles or barbed needles (known as crown needles which
derive their name from the unique spacing of the barbs).
The needles 47 in FIG. 2, will strike into and through the
preferred nonwoven needled web and into a web supporting
portion 48 in FIG. 2, to produce loops (if fork-end shaped
needles are used) or raised, free ends (if crown needles
are used) of the fibers in the web. Structured
needlepunching will be described in more detail with
FIG. 2. Velours are generally soft fabrics with a short
thick pile having a velvetlike texture; they are often
made of cotton, wool, a cotton warp in wool, silk, or
mohair.
The third block in the diagram of FIG. 1 which
says "Passing Fluid Through Needlepunched Web in Direction
from Textured Outer Surface" will be discussed in
conjunction with the descriptions of FIGS. 2-4. Suitable
gases or liquids capable of being heated may be used as
the fluid such as air or water. As suggested by the flow
diagram, the heated web may then be, among other things,
either (1) cooled and stored or cut into pieces/lengths,
or (2) cut into pieces/lengths and thermally formed or
molded by adding heat and pressure, into any three
dimensional shape. If the lowest flow diagram block is
performed, care must be taken not to soften, melt, and/or
crush the loops, raised free ends, or the like, of fibers
if it is desired that the product keep its velour-like
textured outer surface.
-- 8
2007488
1 Nonwoven fibrous panels produced according to
the method of the invention may be used for vehicle trunk
or passenger compartment linings, seat backs, kick panels,
seating, as well as package/storage shelving, or for any
use requiring a dimensionally stable fabric. Such
nonwoven fibrous panels will have a minimum amount of
fiber pullout wear.
FIG. 2 illustrates roll 42 of a preferred
nonwoven needled web 52 being unwound in direction 44.
Needled web 52 is passed through needlepunching apparatus
46 to produce a textured outer surface shown as loops
54. Both first and second type fibers of preferred
nonwoven needled web 52, as well as any other fiber
components interengaged uniformly therein, will become
loops, raised free ends, or the like, of textured outer
surface 54. The proportions of first and second type
fibers in a preferred textured outer surface will be
generally the same as their proportions in the needled web
(the enlarged partial sectional of FIG. 5 illustrates the
web 52 and its outer surface 54 in more detail). Needles
47 may be of various configurations to produce various
velour-like outer surfaces--for simplicity only loops 54
are shown. Examples of acceptable needlepunching
apparatuses 47 are: fork-end shaped needle Structuring
Machines NL ll/S and NL ll/SM supplied by Fehrer AG of
Austria; and crown needle Di-Lour and NL 21RV (Random
Velour) looms manufactured by, respectively, Dilo, Inc.
and Fehrer AG. Since it is likely that the speed at which
web 52 is pulled through needlepunching apparatus 46 will
be different than the speed of web 52 during the remaining
illustrated process, there is shown a break point of web
52. This break indicates the point at which the web with
its textured outer surface could be rolled for storage so
that it can later be introduced into the remaining
illustrated process at any convenient time.
Guide rollers 50a-f are used to guide the
needled web 52 with textured outer surface 54 through the
apparatus of FIG. 2 in the direction shown at 56, 58,
68. Web 52 enters fluid recirculation chamber 40, defined
r
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2007488
1 by heat chamber housing 12, through opening 41 where it is
guided onto heat drum 14 by guide roller 50c. Heat drum
14 has apertures 16 located throughout as better seen in
FIG.3`, and rotates in direction 58 around shaft 18.
Textured outer surface 54 rides over heat drum 14 facing
outwardly so that it will not be crushed or have its
velour-like texture and appearance destroyed. Fan means
28 shown in dashed lines representing a squirrel cage type
fan behind heat drum 14, can be positioned as
illustrated. Fan means 28 (described in more detail with
FIG. 4) will pull the fluid used to melt the second
thermoplastic type fibers, through web 52 and apertures 16
into drum chamber 60. By pulling such fluid (heated to a
temperature that will melt at least a portion of the
second thermoplastic type fibers to produce weld joints,
not shown, thereof) in a direction from recirculation
chamber 40 into drum chamber 60, liquefied second
thermoplastic type fibers will be pulled away from the
textured outer surface 54. Upon rehardening of the small
liquefied thermoplastic clumps created, the textured outer
surface should remain generally velour-like in texture and
appearance. In operation, fan means 28 will effectively
create a pressure gradient across web 52 resulting in the
movement of the fluid found in recirculation chamber 40 in
a direction from the recirculation chamber 40 into drum
chamber 60. Please see FIG. 4 to better understand the
fluid circulation through chambers 40 and 60.
Preferably, a needled web 52 of only first and
second type fibers is made of up to 20~ second
thermoplastic type fibers interengaged and consolidated
together, as mentioned above. Thus, after at least a
portion of second thermoplastic type fibers are heated to
their melt temperature, a preferable nonwoven panel
produced that has at least a majority, if not all, of its
first type fibers left in tact will remain mostly
fibrous. Furthermore, since approximately the same
proportion (i.e. up to 20%) of second thermoplastic type
fibers will be found in a preferred textured outer
t surface, as mentioned above, a preferable nonwoven panel
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-- 10 --
2007488
1 produced according to the method described in the above
paragraph, will have, after processing, a textured outer
surface substantially free of second thermoplastic type
fibers. It can be appreciated that weld joints (not
shown) produced of second thermoplastic type fibers
according to the method described in the above paragraph,
will generally be concentrated away from the textured
outer surface in a preferred nonwoven panel, leaving the
textured outer surface velour-like in texture and
appearance. Once the second thermoplastic type fibers
have been melted, it is believed gravity may play some
role in the final location of weld joints at very low
fluid flow rates through web 52.
Guide roller 50d preferably has a tension
sufficient to pull web 52 from heat drum 14, yet not crush
textured outer surface 54. Guide roller 50e guides web 52
onto cool drum 64 which rotates around shaft 66 in
direction 68 within cooling chamber 70, defined by housing
62. Guide roller 50f guides web off cooling drum 64.
Surface winding rollers 74, driven in the direction
indicated, wind web 52 around spool 73 or other suitable
device into roll 72 for storage. Although not shown, the
nonwoven panel(s) may be cut and thermally formed prior to
preparing the product for storage. Note that heat chamber
housing 12, cooling chamber housing 62, heat drum 14, and
cooling drum 64 can be made of a metal, metal alloy, or
other suitable material having sufficient strength and
heat resistance.
Apparatus 10 of FIG. 3 includes a heat drum 14
with apertures 16 and enclosed at end 17 by a circular
plate (shown at 15 in FIG. 4), capable of being rotated by
shaft 18. Heat drum 14 may be driven in a conventional
manner by means of an electric motor 20 connected by
suitable drive belting 22 to a drive pulley 24. To
simplify the diagram, needled web 52 and its textured
outer surface 54 have been left out of FIG. 3. Fluid
recirculation chamber 40, defined by heat chamber housing
12, is shown to contain the following: heat drum 14;
burner housing 26 suitably mounted on base 27; fan means
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2007488
1 28; as well as flared conduit 30. Shaft 32 for fan means
28 is driven independently from heat drum shaft 18 and may
be driven in a conventional manner by electric motor 34
connected by suitable drive belting 36 to a drive pulley
38. Although fan means 28 is illustrated as a squirrel
cage fan, any suitable fan configuration may be used to
recirculate fluid through recirculation chamber 40 at a
prescribed flow rate. A suitable burner (not shown) for
heating a suitable recirculating fluid such as air, is a
liquid propane Eclipse burner having a rating of 2 million
BTUs. To operate properly, liquid propane burners such as
the Eclipse burner generally need an intake of fresh air
from outside the recirculation chamber 40. A burner fresh
air intake is not illustrated in FIG. 3.
The partial sectional in FIG. 4 illustrates the
direction 80 of fluid flow through fluid recirculation
chamber 40: in operation, fan means 28 draws the fluid
such as air through apertures 16 into drum chamber 60 then
through burner housing chamber 82 (burner not shown) to be
heated and, finally, through flared conduit chamber 84.
If fan means 28 takes some other configuration than that
shown, such as a blade fan housed by suitable housing, the
fan would exhaust the fluid out of its housing into the
recirculation chamber 40 to be reused. Web 52, absent in
FIG. 4, will be guided onto heat drum 14 with its textured
outer surface 54 facing outwardly so that the heated fluid
passes through the web in a direction from the textured
outer surface toward the heat drum 14. Shaft 18 extends
the length of heat drum 14 and is supported at each end by
suitable means. Also shown in FIG. 4 is a fume exhaust
pipe 86 through which, by suitable exhaust fan (not
shown), any fumes given off by the melting of second
thermoplastic type fibers will be discharged along
direction 88.
FIG. 6 illustrates pin ring 90 made up of metal
sections 91 having pins 92 therethrough, fastened by
suitable means 94 to metal belting 96. A minimum of two
pin rings 90 strapped around heat drum 14 at a width
slightly less than the width of a preferred needled web 52
A
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2007488
1 (yet unheated), may serve as a means of minimizing
shrinkage of web 52 during heating by the recirculating
fluid by spearing and holding the edges of web 52 to the
heat drum.
Example 1
By way of example, a nonwoven needled web was
prepared of 13% 6 denier undyed natural polyethylene fiber
and 87% 18 denier solution dyed polypropylene fiber was
blended by interengaging and consolidating with a
needlepunching machine, the loose fibers of approximately
2.5"-3.5" in length to form a generally uniform needled
web. The polyethylene has a temperature melting point of
230-250F and the polypropylene has a temperature melting
point of 320-350F. The needled web was then
needlepunched with fork-end shaped needles to produce an
outer surface of loops of both polyethylene and
polypropylene fibers. The web with its looped outer
surface was then guided onto a heat drum of approximately
70" in diameter at a rate of approximately 20-30 feet per
minute. The heat drum was driven by an electric motor.
An Eclipse burner heated air to a temperature of
approximately 265F to melt at least a portion of the
polyethylene fibers in the web. A fan having a diameter
of approximately 4 feet capable of providing a flow rate
of 30-300 cfm/ft2 (cubic feet per minute per square foot
of web) was used to draw heated air through the fluid
recirculation chamber at a flow rate of approximately 90
cfm/ft2 (cubic feet per minute per square foot of web).
Cooling chamber 70 was held at approximately room
temperature (70F).
While certain representative embodiments and
details have been shown for the purpose of illustrating
the invention, it will be apparent to those skilled in the
art that various modifications may be made to the
invention without departing from the spirit or scope of
the invention.
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