U.S. patent number 3,755,028 [Application Number 05/187,859] was granted by the patent office on 1973-08-28 for method for manufacturing non-woven textile articles.
This patent grant is currently assigned to Curlator Corporation. Invention is credited to Dennis E. Wood.
United States Patent |
3,755,028 |
Wood |
August 28, 1973 |
METHOD FOR MANUFACTURING NON-WOVEN TEXTILE ARTICLES
Abstract
In this process various materials are fed into a condensing
chamber between two rotary condensers to form a composite nonwoven
product. Staple fibers may be formed into two separated mats from
which the fibers are combed by lickerins into two separate air
streams for delivery to the condensing chamber; and continuous
filaments may be fed between the fibers to the condensers, and
intermingled, in the nip between the condensers, with the staple
fibers to form a non-woven and continuous filament composite; or a
powdered binder may be fed into the condensing chamber to form a
two-type non-woven and powdered-binder composite; or staple fibers
may be fed by three separate air streams into the nip between the
condensers to form a three-type non-woven product.
Inventors: |
Wood; Dennis E. (Penfield,
NY) |
Assignee: |
Curlator Corporation (East
Rochester, NY)
|
Family
ID: |
26883478 |
Appl.
No.: |
05/187,859 |
Filed: |
October 8, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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47029 |
Jun 17, 1970 |
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691544 |
Dec 18, 1967 |
3535187 |
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Current U.S.
Class: |
156/62.2;
156/62.4; 156/62.8 |
Current CPC
Class: |
D04H
5/08 (20130101) |
Current International
Class: |
D04H
5/00 (20060101); B32b 019/00 () |
Field of
Search: |
;156/62.2,62.4,62.8,166,180,181,296,501 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Leavitt; Alfred L.
Assistant Examiner: Weston; Caleb
Parent Case Text
This application is a division of my application Ser. No. 691,544,
filed Dec. 18, 1967, now U.S. Pat. No. 3,535,187 issued Oct. 20,
1970 and a continuation of my application Ser. No. 47,029, filed
June 17, 1970, now abandoned.
Claims
Having thus described my invention, what I claim is:
1. The method of manufacturing a non-woven textile web comprising
conveying the fibers by two separate spaced air streams into a
common enclosed chamber and into the nip between two oppositely
rotating foraminous condensers so that the fibers of the two
streams are intermingled and arranged in random manner, and
simultaneously delivering to the condensers into said chamber and
into said nip between the fibers a material different from the
fibers which are carried by the two air streams, so that the
condensers form between them a nonwoven random fiber web composed
of at least two different materials.
2. The method according to claim 1, wherein said different material
comprises continuous filaments.
3. The method according to claim 2, wherein said continuous
filaments are spun fibers selected from the group consisting of
plastic fibers and glass fibers.
4. The method according to claim 1, wherein said different material
is allowed to fall by gravity into said nip, and the condensers are
so disposed that individual fibers delivered into the nip between
the condensers are of sufficient length to extend across said nip
from one condenser to the other.
5. The method according to claim 1 wherein said different material
is a fibrous material, and the fibers carried by the two air
streams are staple fibers.
6. The method according to claim 2, wherein the continuous
filaments are coated with a tacky substance and then fed to the
condensers.
7. The method according to claim 2, wherein some of the filaments
are guided into the chamber into said nip to form warp threads in
said web and other filaments are guided and laid down transversely
of the first-named filaments to form weft threads in said web.
8. The method of manufacturing a nonwoven textile web comprising
preforming fibrous material into two separate feed mats, combing
fibers from the two separate fiber mats by two separate lickerins
rotating at high speed about separate axes, doffing centrifugal
fibers from the lickerins by centrifugal force, due to the high
speed rotation of the lickerins, and by two separate air streams
flowing past the two lickerins, and conveying the fibers by the two
separate spaced air streams into a common enclosed chamber and into
the nip between two oppositely rotating foraminous condensers so
that the fibers of the two streams are intermingled and arranged in
random manner, and simultaneously delivering to the condensers into
said common chamber and into said nip and between the fibers a
material different from the fibers which are carried by the two air
streams, so that the condensers form between them a nonwoven random
fiber web composed of at least two different materials.
Description
This invention relates to a method for producing non-woven textile
articles, that is, textile articles produced without spinning,
weaving or knitting operations.
There are several known methods of preparing non-woven textile
products.
One object of the present invention is to produce non-woven
materials superior to those produced heretofore.
A further object of this invention is to provide an improved,
non-woven textile material. To this end, another object of this
invention is to provide a process which eliminates the formation of
objectionable lumps of fibers in the finished, non-woven web.
A more particular object of this invention is to provide a process
for combining continuous and non-continuous textile filaments into
a textile web, which will exhibit physical properties equivalent to
similar woven or knitted fabrics.
Still another object of the invention is to produce a nonwoven
product stronger than present day nonwoven webs.
Other objects of the invention will be apparent hereinafter from
the specification and from the recital of the appended claims,
particularly when read in conjunction with the accompanying
drawings.
In the drawings:
FIG. 1 is a somewhat diagrammatic, fragmentary sectional view in a
vertical plane through web forming apparatus made in accordance
with this invention and illustrating the process of the
invention;
FIG. 2 is a fragmentary perspective view of a weft laying unit;
FIG. 3 is a fragmentary sectional view similar to FIG. 1, but
showing another manner of practicing the invention;
FIGS. 4 to 6 illustrate schematically and fragmentarily three
additional modifications of the invention;
FIG. 7 is an enlarged, fragmenatry sectional view of the throat
between the rotating condensers of the apparatus, and illustrating
diagrammatically how the fibers are laid down in the formation of a
non-woven web according to the invention; and
FIG. 8 is a section through a web made according to one embodiment
of this invention.
In recent years there has been much work on monocrystalline,
monofilament, and like fibers made in continuous lengths. Most of
these fibers, in particular monocrystalline types, have the
greatest strength of any textile materials made today.
The heart of all nonwoven production is the web formation process,
whether this process be by conventional textile machines, such as
cards or garnetts, which produce a web with a predominant fiber
orientation, or by machines which use a stream of gas or air to lay
down, on a moving condenser, a web in which the fibers have a
random arrangement.
This invention, in one aspect, consists in combining continuous
length fibers with a weaker nonwoven fiber mass to create a whole
new generation of composites stronger than present day nonwoven
products. It has been found that a nonwoven web, made by combining
the two types of fibers mentioned into a composite, retains the
advantages of its constituents and is superior to webs made by
present day processes. Moreover, the combination yeilds a nonwoven
material which has characteristics greater than those of the
constituents alone.
The continuous material may be extruded filaments, bundles of
aligned fibers, strands, threads, yarns, and the like.
The invention, however, is not restricted to the production of
nonwoven textile articles from a mixture of fibers of staple, or
indiscriminate lengths and/or continuous filaments. In certain
aspects, the invention relates to formation of nonwoven webs from
different types of staple or indiscriminate fibers, and also to
instances in which such fibers are bonded together with
thermoplastic resins.
Referring now to the drawings by numerals of reference, and first
to FIG. 1, 20 denotes a part of the frame of a machine for
practicing this invention. Mounted on this frame are two spaced,
parallel, vertically disposed chutes 22 and 23, each of which is
adapted to receive textile fibers transported, for example, by
pneumatic conveying ducts, for instance, such as shown in U.S. Pat.
No. 3,326,609, granted June 20, 1967.
Rotatably mounted beneath the lower ends of the chutes 22 and 23,
respectively, are two spaced, parallel condensers 25 and 26, which
are of conventional construction and may comprise rotary screens
surrounding fixed diametral ducts or rotary screens surrounding a
slotted duct through which air is sucked to one or both ends of the
condenser. The condensers 25 and 26 are disposed beneath the lower,
open ends of the chutes 22 and 23, and confront curved meter plates
28 and 29, respectively, which constitute extensions of walls of
the chutes 22 and 23, respectively. These plates converge
downwardly toward the peripheries of the two condensers so that the
space between the plates and their respective associated condensers
gradually narrows downwardly.
Mounted below plate 22 in proximity thereto is a rotary feed roll
31. Mounted beneath condenser 25 is substantial contiguity
therewith is a rotary feed roller 32. Feed roller 31 rotates in a
pocket or recess 30 in a feed plate 38. Mounted in substantial
contiguity with roller 32 but spaced slightly from the arcuately
curved surface 37 of plate 38 is a rotary feed roller 33. Similarly
mounted at the opposite side of the machine are three, spaced,
parallel feed rolls 34, 35 and 36, respectively. Roller 36 is
adapted to cooperate with feed plate 39.
Plates 38 and 39 constitute the outside walls of chambers 41 and
42, respectively.
Mounted in the lower ends of the chambers 41 and 42, respectively,
adjacent the lower ends of the feed plates 38 and 39, respectively,
are saber tubes 44 and 45, respectively. The right hand chamber 42
has an outlet 47 in its lower end between the saber 45 and the
adjacent feed plate 39. At the opposite side of the machine, the
chamber 41 has in its lower end a first outlet 48 formed by an
elongate slot in the feed plate 38, and a second outlet 49 formed
between the feed plate 38 and the saber tube 44. A pivoted damper
43 in chamber 41 is used to control the flow of air from this
chamber through the outlets 48 and 49.
The saber 44 has a triangularly shaped extension 50 by which it is
pivotally mounted in chamber 41. A leaf spring 43 serves
resiliently to press saber 44 clockwise about its pivot.
It is to be understood, that, if desired, the chambers 41 and 42 at
opposite sides of the machine may be constructed identically --
i.e. both may be like chamber 41, or both like chamber 42.
Mounted to rotate beneath the feed rolls 33 and 36, and adjacent
the outlets of the chambers 41 and 42, respectively, are two
conventional lickerins or swifts 53 and 54, respectively. Guards 51
and 55 extend around the greater portions of these lickerins.
The pneumatically-carried fibers are delivered by chutes 22 and 23
to the condensers 25, 26, respectively; and as the condensers
rotate, and air is sucked through them by a suction fan or fans
(not shown), the condensers and the meter plates 28, 29 cooperate
to collect, condense and from the fibers into laps. The laps are
doffed from the condensers by doffing rolls 32 and 35,
respectively, and guided between rolls 32 and 31 and roll 33 and
feed plate 38 on the one hand, and between rolls 34 and 35 and roll
36 and feed plate 39 on the other hand and thereby compacted into
fiber mats. The mats are fed over the noses of the feed plates 38
and 39 by feed rollers 33 and 36, respectively, into contiguity
with the lickerins 53, 54, respectively. The fibers are combed from
the respective laps by the rotating lickerins.
The rolls 31, 32, 34, 35 may be plain or knurled. The feed rolls 33
and 36 are metallic-clothed with a tooth arrangement reversed with
respect to the teeth of the lickerins.
Mounted beneath and between the lickerins 53 and 54 is a condensing
chamber 54 to which the combed fibers are delivered through spaced
ducts 57 and 58 which open at their upper ends on the peripheral
surfaces of the lickerins 53 and 54, respectively. These ducts are
defined by inner or upper walls 59 and 60, respectively, and by
outer walls 63 and 64. Upper walls 59 and 60 extend from the lower
ends of the chambers 41 and 42, respectively, downwardly and
inwardly toward one another, and are connected at their lower ends
by a horizontal plate 61 that extends transversely across the upper
end of chamber 56.
The opposed, outer walls 63 and 64 of these ducts are spaced and
curved covers which maybe made of "Plexiglas," or the like. These
covers may extend around lickerins 53 and the integral with guards
51 and 55 or be hinged thereto. The lower ends of the covers 63 and
64 terminate in approximate contiguity with spaced, parallel,
rotary condensers 69 and 70, which are adjustably mounted on the
frame of the machine for lateral movement toward and away from one
another to adjust the width of the throat T or space formed between
the confronting peripheries of these condensers.
The condensers 69 and 70 are disposed slightly above a conventional
endless conveyor belt C that is adapted to be mounted beneath the
condensers 69 and 70 to travel over pulleys 71.
The center zone or section of the machine is disposed between the
chutes 22 and 23. Mounted in the upper end of this section in the
embodiment of the invention illustrated in FIG. 1 are means for
supplying continuous filamentary material. This supply may be from
creels 72, only one of which is shown, but which are disposed in
spaced relation widthwise of the machine, and each of which holds a
plurality of bobbins 73 (only one of which is illustrated), or in
the form of a warp beam or beams 74 extending across the width of
the machine and mounted to rotate parallel to the condensers 25 and
26, or both creels and warp beams may be employed. In the drawings
(FIG. 1) a creel is shown at one side of the machine, and a warp
beam at the other side.
As shown by broken lines in FIG. 1, the continuous filaments or
warps F from the rotating bobbins 73 and/or beams 74, which are
driven in conventional manner, are guided by spaced rods 76,
preferably made of glass, downwardly through the center of the
machine between the chambers 41 and 42, into the condensing chamber
56. Some of the filaments or warps may be guided into the chamber
56 through nozzles 77 that are formed in plate 61 adjacent one side
(the right side in FIG. 1) of the machine. Others of these
filaments may be threaded through a weft laying unit 78 of
conventional construction, which is mounted to reciprocate on guide
rods 79 between opposite ends of the machine above plate 61.
As shown more clearly in FIG. 2, the weft laying unit 78 may
comprise one or more perforated bars 80 that are mounted on a
cariage 81, which rolls through rollers 82 on rods 79. A sprocket
wheel 85 rotatably mounted on one side of the carriage 81 may be
driven in conventional manner by a chain 86, and through a
conventional drive (not illustrated), may transmit its rotation to
one or more of the rollers 82, thereby to move the unit 78 in
opposite directions depending upon the direction of movement of the
chain 86.
In use, non-continuous filament or staple fibers are fed by the
chutes 22 and 23 to and deposited on the condensers 25 and 26 and
compacted between the condensers and the meter plates 28 and 29
into laps which are fed by rolls 31, 32, 33, and 34, 35, 36,
respectively, to the lickerins 53 and 54, as in conventional
machines for forming random fiber webs. The lickerins, which rotate
at high speed, comb individual fibers from the mats. These fibers
are doffed from the lickerins into chamber 56 by centrifugal force
and by the velocity of the air streams flowing over the lickerins
toward the condensers 69 and 70, respectively.
In forming a composite nonwoven web W, the fibers of indiscriminate
and/or staple lengths are, under the influence of the turbulence
existing in the atomization or condensing chamber 56, augmented by
the presence of the continuous filaments. The fibers are deposited
in a haphazard manner on the condenser screens with the continuous
filaments. In such as assembled mass, many of the fibers extend
from one major face of the web to the other and from one continuous
filament to the next. The fibers that extend through the web and
between the continuous filaments provide a direct tie so that the
web becomes an integrated structure from the upper to the lower
surface. The shorter, staple fibers collect in part on the surfaces
of the condensers 69 and 70, and in part in the throat T (see FIG.
7) between the condensers, and around the vertically disposed
continuous filaments F. Moreover, many of the staple fibers operate
as linking fibers 90, each of which has one end thereof embedded in
the layer of fibers formed on the surface of the condenser 69, and
has its opposite end embedded in the fiber layer formed on the
surface of the condenser 70. These linking fibers 90 extend
transversely across the throat T, and to opposite faces of the web
W formed by the fibers upon passing downwardly through the throat
T. The linking fibers 90 prevent opposite faces of the web from
separating, and as a result produce a single web W, which is a
composite of the fibers fed into chamber 56. Web W thus created is
fed downwardly into, and is conveyed away by the conveyer C.
It is essential in order to provide a satisfactory web W, that
there be a continuous, uniform supply of fiber to each side of the
machine, and ultimately to the condenser chamber 56. It is
important, too, that a uniform rectangular cross-section of
material be presented to each swift or lickerin. The lickerins comb
individual fibers into the condensing chamber. The uniform
rectangular feed sheets, which have been formed by the action of
the condensers 25, 26, the meter plates 28, 29 and the feed rolls
31, 33, 34, 36 supply the fibers in an alignment which increases
the uniformity, across the width of the condensing chamber and the
venturi sections, of the fibers deposited in the air streams and
increase the consistency of the distribution of the fibers from top
to bottom of the air stream by increasing the consistency of the
rate at which the fibers are removed from the laps by the combing
action of the lickerins.
Air is forced axially through the openings in the chambers 41, 42
by the exhaust from the recirculation fans for condensers 25, 26
which are connected at one end to ducts that are connected at their
other ends to chambers 41, 42. Preferably the axial velocity of the
air at the point where it passes between the surfaces of plates 38
and 39 and the lickerins is greater than the peripheral speeds of
the lickerins. This avoids windage drag on the fibers being carried
partly on the teeth of the lickerins and partly in the bound layers
around the lickerins, and causes each individual fiber to be
encapsulated by the air. This encapsulation is important since it
reduces frictional resistances and the possibility of coagulation
of the fibers.
To assure uniform fiber supply, the chambers 41 and 42 are supplied
with air under pressure in conventional manner from the
recirculating fans, or the like, and function as expansion chambers
for incoming air, so that as the air enters these chambers, from
the smaller cross-sectional area ducts it expands. Thus the air
will have a relatively high velocity in the inlet ducts leading
into chambers 41 and 42, and a relatively low velocity in these
chambers themselves. This produces an aerodynamic turbulence in the
form of a cylindrical rolling motion of the air across the width of
the machine.
The amplitude of this transverse cycloidal motion can be regulated
by changing the suction velocities of the fans. This rolling motion
of the air tends to result in axial air flow which is of average
uniformity across the machine and prevents laminations of the flow
at the velocities used.
Having obtained uniformity across the widths of the chambers 41 and
42 by expansion of the air, which results in reduced air velocity,
the velocity of the air, which is to be expelled from the chambers,
must be increased. The slots fromed between the undersides of the
feed plates 38, 39 and the saber tubes 44, 45, respectively, are
accordingly made of reduced rectangular cross section. This causes
acceleration of the air, which enters at points where the fibers
are fed into the venturi sections which have rectangular cross
sections less than those of the acceleration slots. This reduction
in depth of the condensing chambers and increase in velocity of the
air stream reduces the magnitude of the transverse movements which
are induced by turbulence, thus, in effect compressing the large
movements of air into a number of small amplitude movements and
causing a more uniform axial movement of the air and fiber
mixture.
The air mixture is introduced at a zone of uniform flow achieved by
the small lateral turbulence and high velocity, namely in zones,
such as bounded by lines a and b for saber 44-lickerin 53.
Thereafter the air and its suspended fibers travel uniformly as
regards the width of the condensing chamber and the fibers are
deposited uniformly across the widths of the condensing screens 69,
70.
It has been found that if a change is made in the raw material, as
for example, length and/or denier of the stock, or if a change is
desired in the weight of the nonwoven web to be produced, the
velocity of the air should be changed correspondingly. Should the
air velocity be too high, the impact of the fibers on the
condensing screens 69, 70 would be too severe; and should the air
velocity be too low, coagulation of the fibers would occur due to
the fibers not being encapsulated correctly. Therefore, a balance
must be achieved in the air velocity in the condensing chamber such
that individual fibers have just enough kinetic energy to deposit
themselves in an isotropic web formation. The required variation of
air can be achieved by balancing the air flow through the fans and
so into the expansion chambers 41, 42, and by adjusting the
positions of the sabers 44, 45 thus adjusting the acceleration
slots.
It has been found that certain fibrous materials tend to accumulate
or "ball up" between the feed rolls 33, 36, and their associated
lickerins 53, 54, on the downstream side of the tangent point of a
feed roll and lickerin, or just below where the fibers are removed
from a feed lap. This is most undesirable, since the accumulated
fibers will eventually escape from this zone, and will cause an
uneven discharge into the condensing chamber 56. The outlet 48 is
provided to obviate this "balling up." The outlet 48 creates an air
current or turbulence immediately adjacent the point where the
fibers tend to accumulate, and as a consequence prevents
accumulation.
The theoretical or ideal amount of air required for air-layed
random webs is that amount which is necessary to open the lap feed
into individual fibers, and to encapsulate each fiber in a sphere
of air, and then to pass these air encapsulated fibers upon the
rotating condensing screens 69 and 70 so that no fiber touches or
joins its neighbor en route.
For example, if the material to be processed is cotton fiber of 1
inch staple length and a denier of 11/2 inches with a specific
gravity of 1.53, then there will be 6,696,250 fibers per oz.
Therefore, the required air to encapsulate 1 oz. of the cotton
fiber is 2,290 cubic feet. If the machine output is only a modest
80 lbs./hr. then the air requirement would be 48,853 cubic feet per
minute. This is not practicable, so a compromise is made such that
a dilution factor is used to maintain as nearly as possible these
ideal conditions wherein coagulation and frictional resistance are
kept to a minimum. It has been found that the required air may be
caluclated from the formula 810.P.L.sup.2 /D.k
where P = Production rate of the machine is lbs./hr.
L = Fiber length in inches
D = Denier
k = Dilution factor
The above formula is empirical.
In the apparatus shown in FIG. 1, three separate feed zones are
employed: two at opposite sides of the machine as represented by
the chutes 22 and 23, and a third in the center of the machine as
represented by the creel 72 and warp beam 74. The center zone
provides the continuous filaments, which are blended in the space
between the condensers 69 and 70 with the non-continuous fibers,
which are fed into the condenser 56 from the two outer zones. By
modifying the center zone, the structure of the resultant nonwoven
web may be altered.
For example, in the modification illustrated in FIG. 3, wherein
like numerals are used to designate elements similar to those
employed in the first-described embodiment, it will be noted that
although the two outer feed zones are substantially the same as in
the machine of FIG. 1, the creel 72 and warp beam 74 of the inner
zone have been replaced by means for supplying non-continuous
filament or staple fiber.
In this second embodiment a chute 92 in the center of the machine
feeds fibers to a condenser 94 that is located between and parallel
to the condensers 25 and 26. A lap is developed in the usual manner
between condenser 94 and adjacent meter plate 95, and is fed
dowwardly by a plurality of plain or knurled feeder rolls 96, 97,
98 and 99 and over a feed plate 101 to a lickerin or swift 100 that
is located in the center of the machine above condensing chamber
56. The saber 44 is mounted in the lower end of a chamber 102,
which is similar to the chamber 42 in the first embodiment, and
which has a single outlet 103 adjacent the saber to assist in
delivering fibers to the condenser inlet 57 as they are removed
from the lap by the lickerin 53.
Similarly, the saber 45 is located in the lower end of a chamber
105 having a first outlet 106 adjacent the lickerin 54 to assist in
delivering fibers to the condenser inlet 58, and a second outlet
107, which is located between the lickerin 100 and another saber
108 mounted in the lower end of the chamber 105 adjacent lickerin
100. Mounted beneath the lickerin 100 is a rotatable doffing bar or
roll 110, and an adjustable deflection unit 112, which cooperates
with a stationary plate 113 that extends downwardly beneath saber
108 to direct fibers from the lickerin 100 into chamber 56. This
plate, in effect, is the fiber attenuating duct floor and upper
section for the adjacent web formation units.
It will be appreciated that with the machine illustrated in FIG. 3,
three completely different varieties of materials may be
manufactured into a web W. For example, cotton fibers could be fed
to chute 22, metallic fibers to center chute 92, and manmade or
synthetic fibers to chute 23. The resultant web will have three
different materials combined into an integrated web.
In the embodiment illustrated in FIG. 4 the center zone comprises a
bin 115 adapted to hold a powdered binder, such as a phenolic
resin. This bin extends across the machine between chambers 41 and
42, and has sidewalls 116 and 117 that are secured at their upper
ends to the inner walls of chambers 41 and 42, respectively, and
that converge downwardly. Mounted in the bin 115 is a conventional
breaker rod assembly 120 for agitating the contents of the bin.
This comprises a twin set of breaker arms 118, 119 which may be
driven independently to feed the granular or powdered material in
the hopper to the discharge port.
Mounted on the outside of plate 116 at the bottom of bin 115 is a
conventional vibrating gage knife assembly 130, which is set to
control the flow of the contents of the bin 115 out of the port 132
in the lower end of the bin onto a dispensing or feed roller 134,
which is mounted beneath port 132 to rotate parallel to the
condensers 69 and 70.
In use, a powdered or granular binder such as a phenolic resin, or
the like, is placed in the bin 115 and fed continuously and at a
predetermined rate, by the vibrating gage knife assembly 130, onto
the roller 134 for distribution thereby into the upper end of the
condensing chamber 56. For certain types of powder it has been
found necessary to incorporate vibrating dispersion wires 36
adjacent to and around the roll 134 to loosen any particles that
may tend to compact on the surface of this roll.
An important feature is that bin 115 is positioned just above the
condensers 69 and 70; and the plates 138 and 140 are disposed to
extend, respectively, between the feed roller 134 and the floor
plate 60, and between the vibrating knife assembly 130 and the
floor plate 59, thereby to prevent any powder or other granular
material, that is fed out of bin 115, from being recirculated
through the upper working parts of the machine, where it might
cause blockages, or contaminate the bearings of the many rotating
elements of the machine. The air flowing through the ducts 57 and
58 into the condensing chamber 56 distributes the powder, that is
fed into the chamber by the roller 134, equally throughout the twin
web or matrix being formed on the condensers 69 and 70.
In the embodiment illustrated in FIG. 5 the two outer zones are the
same as in the embodiment illustrated in FIG. 4, but the center
zone is modified to include a forehearth furnace 142 for supplying
molten glass to spinnerets 144 connected at the bottom of the
furnace. The spinnerets from spun glass filaments F and deliver
them to an enclosure 146 in which a lubricant is applied to the
filaments. They then pass through a cooler 148 to the upper end of
a hollow forming hood 150. Hood 150 extends downwardly between the
ducts 41 and 42, and opens on the upper end of the condensing
chamber 56 between the lower edges of the floor plates 59 and
60.
The continuous glass filaments enter the upper end of chamber 56
and are guided by the hood 150 directly downwardly into the nip
between the condensers 69 and 70, where they are stretched and
formed, together with the fibers entering the inlets 57 and 58 into
a web W in a manner similar to that described above.
Instead of producing glass filaments, the apparatus illustrated in
the center zone of FIG. 5 may also be utilized to produce other
types of man-made filaments or fibers such as cellulose acetate
fibers or nylon filaments. Heated air may be forced through the
forming hood 150 to remove undesirable quantities of volatile dope,
which may be present on the fibers or filaments.
In FIG. 6 a further modification of the process has been
illustrated, which is achieved by modifying the center zone of the
machine to feed continuous filaments or yarns which are taken from
creels and/or warp beams mounted in the top of the machine as, for
example, in FIG. 1, and which are coated with a natural or
synthetic type foam material. The foam material may be a
thermoplastic such as ethylene, styrene, urethane, a plastic resin,
or a dispersion of a natural or artificial foam rubber.
By projecting these tacky, foam-coated continuous filaments into
the matrix or web, it will be seen that the fibrous material formed
constitutes an extremely novel resilient and lofty material wherein
there are continuous foam rubber filaments running throughout the
length, dpeth and width of the nonwoven web so that the fibrous
materials, which are trapped between the foam castings, form links
such that the fibrous material will be bonded between adjacent
coated continuous filaments giving the web high resilience and
loft.
In FIG. 6 continuous filaments 150 are fed downwardly through the
center zone of the machine, where they are guided by glass rods 156
around one side of a doctor roll 158, which is mounted to rotate
adjacent the upper end of floor plate 60 parallel to the condensers
69 and 70. The bottom of the doctor roll 158 extends into a tank
160, which is secured to the inside of plate 60 beneath the roll
158. The tank 160 contains a tacky material such as, for example, a
natural or synthetic foam rubber, or any foamable thermoplastic
substance, or thermosetting resin. The rotating doctor roll 158
picks up the foam from the tank 160 and applies it to the
continuous filaments that extend over, or engage one side of the
roll. This provides tacky, foam-coated continuous filaments that
are guided downwardly into chamber 56. As these coated filaments
extend downwwardly into the throat T between the condensers 69 and
70, the fibrous material entering the ducts 57 and 58 is blended
with these filaments to form, in a manner similar to that
above-described, a web W.
FIG. 7 is a diagrammatic section showing the matrix bridge between
condensers 69 and 70 during formation of a film web comprising
short fibers and longer fibers or continuous filaments. The longer
fibers 90, which extend from the matrix surface of one condenser to
the matrix surface of the other condenser, are in such position
that when the web is fully formed, they constitute a bridge or link
across and between the upper and lower surfaces of the web.
The truly isotropic zoned or composite nonwoven webs, which are
processed to form the products of this invention, may contain
natural or synthetic, vegetable, animal or mineral fibers such as:
cotton, silk, wool, hogs hair, sisal; synthetic or man-made fibers
such as the cellulosic fibers, notably viscose, or regenerated
cellulose fibers, cellulose ester fibers such as cellulose acetate
and cellulose triacetate; the polyamide family of fibers such as
nylon 6, nylon 66 and nylon 610; protein fibers such as "Vicara,"
halogenated hydro carbon fibers such as "Teflon"
(polytetrafluoroethylene); hydrocarbon fibers such as polyethylene,
polypropylene, and polyisobutylene; polyester fibers such as Kodel,
Tereylene; vinyl fibers such as Vinyon and saran; acrylic fibers
such as "Dynel," "Verel," "Orlon," "Acrilan," "Creslan;" mineral
fibers such as glass, aluminum oxide, graphite, silicone carbide,
silicone nitride, tantalum carbide, etc; thermoplastic or
thermosetting extrusions, such as polymeric amides, vinylidene
chloride, quartz and acetone solutions, protein base minerals, and
petroleum derivatives.
As previously indiated, the air depression at the confronting
condenser surfaces is just sufficient for the individual fibers to
have enough kinetic energy to displace themselves in a truly
isotropic nonwoven web whose upper and lower surfaces are of the
same configuration. This contrasts with the prior art since
heretofore the upper and lower surfaces of nonwoven random fiber
webs have varied from one another because one surface would have a
large percentage of fibrous material with a low mass while the
other surface would have an excess percentage of fibrous material
with a high mass.
Also nonwoven webs as heretofore formed have had an undesirable
shingle effect or diagonal layering from the top surface to the
lower surface. This is because the condenser surface is a
continuously moving surface and the air-borne fibers tend to be
attracted to the uncovered or least covered portions of this
surface, the line of least resistance, which is continuously being
rotated into the web-formation chamber so that the matrix is first
formed on the area of the condenser screen entering that chamber.
Thus, build-up of the fibers has two component motions, one
circular and one rectilinear. The resultant motion of the matrix
surface formed is that of a helix. The amount of material and the
surface speed of the condenser allow the continuously moving
surface of the matrix to be formed until the required weight or
depth of material is obtained.
In forming a web in such a manner, the suction or depression at the
condenser surface is diminished as the thickness of the web
increases. Therefore discrimination of individual fibers is caused
giving rise to the difference in upper and lower surface
configuration, and to the shingle effect.
By contrast, a nonwoven web formed according to the present
invention may have upper and lower surfaces of the same
configuration by feeding like materials through the two outer ducts
22 and 23 (FIG. 1) of the machine, for instance. Should the
materials fed into the two outer sections of the machine differ
greatly from one another in length, denier, color, type, etc.,
however, the top and bottom surfaces of the finished web obviously
will be of different texture and/or appearance. By adjustment of
the twin condensers 69, 70 relative to each other, the matrix
formation bridge moreover, may be reduced or increased, and the
longer fibers locked through the nonwoven web. The web may be truly
isotropic the fibrous material being randomly arranged in all
directions throughout the width, length, and depth of the web.
There are innumerable fibers which extend transversely throughout
the depth of the web; and these fibers aid in tying the web into
and integral sructure, and impart to the web increased strength,
resilience, and loft.
The absence of suction or of reduced pressure at the condenser
surfaces allows the web to emerge from between the condensers in a
continuous integrated web in a thickness determined by the quantity
of fibrous material introduced, the resilient expandability of the
material, and the spacing between the condenser cylinders.
Instead of feeding continuous filaments in the center section of
the web as illustrated in FIG. 1, the continuous material may be
cut film, that is, rolls of plastic film can be substituted for
warp beam 74 and run over a series of closely-spaced cutting heads
so that thinly-cut strips are formed to be incorporated in the
nonwoven web in such a manner similar to the filaments F of FIG.
1.
With the present invention, moreover, three layered webs of
different materials can readily be produced. FIG. 8 shows one such
web. Here the top portion 195 of the web may be of 20 denier 1/2
inch nylon fibers, for instance, the middle portion 196 may be of 5
denier 1 inch rayon, for instance, and the bottom portion 197 may
be made of wood fibers, Moreover, the different layers may be of
differently colored material. Top portion 95, for instance, may be
made from nylon dyed yellow; middle portion 96 may be made from
red-dyed rayon; and bottom portion 97 may be made of white bleached
wood pulp fibers. It is to be noted that in the web illustrated in
FIG. 8 some of the longer fibers are locked through the web and
extend from top to bottom of the web.
The layers of the web, however, obviously may be all of the same
color and may differ only in denier. For instance, the top layer
may be of 5 denier, the middle layer of 3 denier, and the bottom
layer of 1 denier. The web may also be made from two different
materials, with top and bottom layers the same. Thus, the top and
bottom layers may be of acrylic fibers; and the middle layer may be
made of polypropylene. On the contrary all three layers of a web
may be made of the same basic material, but in different fiber
lengths and/or colors. Thus, all three layers may be made of rayon,
the upper layer being made from red rayon whose fibers are 1/2 inch
in length, the middle layer being made from white rayon, whose
fibers are 1 inch in length, and the bottom layer being like the
top layer in that it is made from red rayon fibers but these fibers
being on the other hand 2 inches in length. Another example of the
possibilities achievable with the machine of this invention is a
web made of three different materials, as, for example, nylon,
wool, and dacron, the three different materials being laid down in
substantially three different layers.
The web formed in any event may be drafted to the take-off conveyor
C (FIG. 1) and delivered to any desired subsequent process.
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