Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
lC)S'~S18
This invention concerns improvements in and relating
to a nonwoven fabric that is particularly suited for use as
primary backing for cut-pile tufted carpets,
U,S.Patent 3,502,538 discloses a nonwoven carpet back-
ing made from polypropylene filaments~ The bonded nonwoven is
made from unbonded webs which contain filaments or filament seg-
ments which differ from each other in orientation (i.e., bire-
fringence). The less highly oriented filaments or segments are
referred to as binder fibers and the more highly oriented ones
are referred to as matrix fibers. The degree of orientation is
controlled by the amount of drawing given the filaments prior to
being deposited onto a receiver to form a random nonwoven sheet.
A method is disclosed in U.S.Patent 3,563,838 for
preparing a primary carpet backing of nonwoven fabric made of
the above described matrix and binder fibers of polypropylene.
This nonwoven fabric is constructed of at least two layers.
The filaments in one layer are disposed primarily in the machlne
direction (i.e., the general direction of length dimension of
the nonwoven fabric, which also corresponds to the direction of
the moving belt on which such nonwovens are made); this type of
layer is referred to as an M layer. The filaments in an adjacent
layer are disposed primarily in a direction perpendicular to
the filaments of the M layer, or in a cross-machine direction;
this type of layer is referred to as an X layer. The layers of
these nonwoven webs also contain a smaller portion of filaments
that are disposed in the bias directions. Nonwoven sheets having
an MX sequence of layers and sheets having an MXM sequence of
layers are disclosed. When these sheets are bonded in saturated
steam,primary carpet backings having a high tufted-tongue-tear
strength and a low neckdown in ~ck dyeing are obtained.
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U.S. Patent 3,821,062 discloses a layered nonwoven,
polypropylene-filament, primary carpet backing which is an
improvement over the backings disclosed in the above-described
U.S.~tent 3,563,~38, The two backings differ from each other
primarily in binder content, matrix filament denier, matrix
filament tenacity and binder and matrix distribution. The bonded
product has a reasonably low neckdown in beck dyeing and has a
high tear strength after the usual latex application required
in making the tufted carpets, a high proportion of the tear
resistance is retained even after latexing However, at relatively
low basis weights, these nonwoven fabrics have undesirably low
optical cover.
Although each of the above-described polypropylene
filament nonwoven fabrics have been useful as backings for some
tufted carpets, we have found that these prior art non~,rovens
have certain shortcomings when used in the production of cut-
pile tufted carpets. During the tufting process for making such
carpets, abrasion of the tufting needle occurs as the looper
pulls the loop of carpet yarn off the needle. The abraded or
burred needle thereafter often cuts the primary carpet backing
as the backing moves forward against the needle, We have also
found that there is a tendency for some of the prior-art non-
woven backings to develop fuzz (or balls of fiber) during
beck dyeing of the carpet, When the usual secondary backin~
is applied, these balls of fiber cause areas of poor delamina-
tion resistance,
To minimize or overcome the aforementioned shortcom-
ings, the present invention provides an improvement over the
nonwoven backing of U.S. Patent 3,821,062. In particular, the
present invention provides a bonded nonwoven fabric of isotactic
polypropylene filaments comprising a machine direction layer M
at each surface of the fabric and a cross-machine direction
layer X which consitutes 40 to 60% of the total fabric weight,
each layer consisting essentially of 65 to 90~ by weight of
matrix filaments and 10 to 35% by weight of isotactic poly-
propylene binder, the filaments being disposed in each layer
such that the layered fabric has directionality values o~ at
least 1.5 for MD/45, at least 1.5 for XD/45 and of 3.5 to 30 for
(MD + XD)/45, characterized in that the matrix filaments of
~0 each M layer have an average denier of 6 to 20 and a tenacity
of at least 2 grams per denier and the matrix filaments of the X
layer have an average denier of 26 to 60 and a tenacity of at
least 3 grams per denler, which is at least 10~ higher than
the tenacity of the matrix filaments of each M layer, In a
preferred nonwoven fabric of the invention, each M layer is 20-30%
of the total fabric weight,
The present invention also provides a process for
preparing the above described nonwoven fabrics, In this process
an unbonded nonwoven sheet is formed by successively depositing
layers of melt-spun and drawn isotactic polypropylene filaments
on a moving belt such that a machine direction layer (M-layer~
is ~irst formed, on top of which is deposited a cross-machine
layer (X-layer), and finally a second machine-direction layer
is deposited (M-layer) on top of the X-layer, the conditions of
melt-spinning~ drawing and rate of deposition being controlled
so that the X-layer constitutes 40 to 60% of the total weight
of the layered sheet and each layer consists essentlally of 65
to 90% by weight of matrix filaments and 10 to 35% by welght of
binder filaments or binder segments,the ~ilaments being direction-
ally deposited to provide the sheet with directionality values ofat least 1,5 for MD/45~, at least 1,5 for XD/45 and o~
3.5 to 30 for (MD + XD)/45, and the thusly formed sheet is then
s~
thermally bonded under restraint characterized in that the
spinning and drawing are controlled to provide the matrix
filaments Of the M layers with an average denier per filament
of 6 to 20 and a tenacity of at least 2.2 grams per denier,
the matrix ~ilaments in the X-layer with an ~verage denier per
filament of 26 to 60 and a tenacity of at least 3.3 grams per
denier, which is at least 10~ higher than the tenacity of the
matrix filaments in each M-layer, and the b~nder filaments in
all layers with a break elongation of ~00 to 800%.
The thermally bonded nonwoven ~abric of the invention
achieves the combination of properties desired for primary back-
ings of tufted pile carpets because of the special combination
of layers having specific ~ilament characteristics. In the X-
layer, the matrix filaments are of higher denier and higher
tenacity, the latter indicating higher molecular orientation.
Because of their higher molecular orientation, the ~ilaments of
the X-layer are only moderately bonded together compared to the
filaments in either o~ the M-layers. These X-layer filaments,
therefore, hav~ a high degree of mobility within the bonded
fabric such that when the fabric is penetrated by the needles
of the tufting machine, the filaments can readily move with
respect to the needles thereby avoiding being cut by abraded
tufting needles Furthermore, the combination of high denier
and high tenacity in the matrix filaments of the X-layer pro-
motes resistance to tearing in the machine direction of the
tufted carpets.
The matrix filaments in each M-layer of the bonded
nonwoven fabric are of lower denier and moderate tenacity
(moderate orientation). These filaments have a moderate
3o
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~ (~5'~
breaking strength and less resistance to cutting by the needles
durlng tufting, However, high resistance to cutting is not as
necessary in the M-layers because the tufting needles move sub-
stantially parallel to the M-layer filaments and, therefore, are
less likely to cut them. ~he moderately oriented matrix filaments
in the M-layers are readily bonded to the binder filaments and to
each other, thereby providing high resistance to neckdown as well
as high resistance to fuzzing without much loss in tear strength.
The use of moderately oriented matrix filaments in the M-layers
also permits lower temperaturesor shorter exposure times to be
used during thermal bonding, Resistance to neckdown and fuzzing
are highly desirable for carpets that are beck dyed. The
surface layers of the carpet backing should be provided with fuzz
resistance. The relatively low denier of the filaments in each
M-layer also serves to improve the optical cover of the layered
fabric
The binder materlal in each layer of the bonded sheet
conslsts of fused or partlally fused polypropylene derlved from
filaments of low orientation which are substantlally melted in
the bonding operation. The unbonded precursor sheet contains
filaments with essentially three levels of molecular orientation:
(1) low orientation in the binder of the M and X layers, (2)
moderate orientation in the matrix filaments of the M-layers and
(3) high orientation in the matrix filaments of the X-layer.
While the moderately orlented and highly orlented matrix fila-
ments are not substantially altered by the thermal bonding opera-
tion, the lowly oriented filaments are ~used or partially fused.
-- 6 --
~05'~S18
The directionality of the fibers in the Various layers
is also important~ An XD/450 (de~ined below) of less than 1.5
tends to lower the tu~edtongue tear strength while an MD/45
of less than 1.5 tends to promote higher neckdown in dyeing or
other hot processing operations~ In addition~ it has been found
that the desired balance of low neckdown and hi~h tufted-tongue-
tear-strength is not obtained when the weight o~ the X-layer or
the total weight of the M-layers is as high as 70% of the total
fabric weight. As noted above, the X-layers of the layered sheet
of this invention therefore constitute 40 to 60% of the total
fabric weight, with the M-layers each constituting between 20 to
30% of the total fabric weight.
For convenience in describing the process of this
invention, we use a series of letters to indicate the sequence
in which the layers of the sheet were deposited, starting with
the bottom layer and continuing sequentially to the top layer.
Since the product can be viewed from either surface, only the
relative placement of the layers ls important in characterizing
the product. Thus, in accordance with this system, a sheet
designated MXM would indicate that an M-layer was the first
deposited layer, followed by an X-layer deposited on top of it,
which in turn has another M-layer deposited on it. A large
number of ~ets may be used across the width of a collecting
belt to deposit a single M layer or X layer. In addltion several
banks of ~ets may be used in succession. If successive banks
of ~ets deposi.t filaments in the same general direction, then
the collected material may be considered to be a single layer.
To assist better understanding of the process of this
invention, the following figures are included in which:
Figure 1 is a schematic cross-sectional view of a melt
i~5'~518
spinning and quenching apparatus useful for preparing the high
denier highly oriented, polypropylene filaments used in the
nonwoven sheet of the invention. r
Figure 2 is a schematic representation of an apparatus
for drawing and depositing a ribbon of filaments on a moving
belt.
Figure 3 is a perspective view of four air jet devices
for deflecting filaments into layers each having a direction-
alized pattern.
A general description of suitable means for carrying
out the process of the present invention is found in U.S.Patent
3,563,838. However, an improved mechanism is preferably used for
melt spinning and quenching of the polypropylene filaments in
t the X-layer of the nonwoven fabric of the present invention. In
particular the flow of cooling air is carefully controlled to
attain rapid cooling without unduly disrupting the threadline.
The apparatus of Figure 1 shows a modification of the apparatus
of U.S.Patent 3,705,227. This apparatus may optionally be used
for filaments in the M-layers but is particulary useful for
filaments in the X-layer. As shown in Figure 1, melt spun poly-
propylene filaments 4 issue from spinneret plate 1 having ori-
fices ~not shown) set in a circular pattern and pass through a
radial quench device 2 to a forwarding roll 22. An inverted
cone air deflector 3tis attached to the spinneret plate. Flow
restrictors 5 and 6 are provided at the upper and lower ends,
respectively, of the quench device 2. In the particular modi-
fication which is provided for spinning the highly oriented
high denier filaments~ the flow restrictors are elliptical in
shape and are so situated that a basically straight line (with
only minor deflections) may be constructed from any point on the
105;~S~8
outer circle of spinneret orifices through a point on the inner-
most surface of flow restrictor 5 and similar point on flow
restrictor 6 and finally to the first forwarding roll 22 in the
filament drawing apparatus. At the same time the major axes of
the elliptical surfaces of flow restrictors 5 and 6 lie in a
plane which ~s tangential to the surface of the roll 22, This
allows better conformance to the natural shape of the threadline.
This particular construction of the apparatus of U,S.Patent
3,705,227 permits exceptionally efficient quenching thereby
lG avoiding filament sticking and promoting the formatlon of highly
oriented high denier filaments at high spinning speeds.
The openings at the top and bottom of the quench device
are sized such that the ma~or resistance to flow occurs at the
bottom end of the quench device, thereby forcing a ma~or part
of the quench air through the upper end of the quench apparatus.
Quench air is admitted via inlet conduit 7 and distributed as
hereinafter described so that it is directed radially inward
against the filament threadline entering the quench chamber,
thereafter the flow restrictors 5, 6 cause a ma~or portion of
the air to emerge from the upper end of the quench chamber 2 and
to flow upward for a short period of time through the center of
the hollow bundle of filaments 4. The air then meets the con-
ical flow deflector 3 and is redirected radially outward through
the threadline. The length of the conical flow deflector and
the quench air flow rates to be used are dependent on many
factors such as the number of filaments, throughput per hole,
spinning temperature, etc.
A smoke removal device is normally employed in the
melt spinning of polypropylene containing certain stabilizing
additives which tend to sublime or decompose at the spinning
temperature thus forming ~umes at the spinneret face, This
device also improves the quenching,
The ~ilaments are passed downward through a quenching
chamber, the walls for which are formed from a cylindr-Lcal fora-
minous member 16, Plenum chamber 19 is supplied with air or
Other cooling gas through inlet 7 at a pressure slightly above
atmospher~c to provide a uniform radial ~low of cooling gas into
the quenching chamber through the foraminous member.
The bundle of f~laments 4 passing from flow restrictor
6 is elliptically shaped with the ma~or axis of the ellipse in
a plane tangent to the surface of roll 22, In Figure 1 the
cross-sectional cut is taken along the minor axes of the ellipses
at 5 and 6. The broadest axes of the ellipses are each parallel
to the axis of roll 22,
As shown in Figure 2, the elliptical bundle of fila-
ments 4 becomes a ribbon of parallel filaments as it passes over
roll 22, The yarn then travels successlvely to rolls 23, 2ll, 25,
26 and 27, The yarn travels at increasingly greater speed at
each successive roll, The greatest speed increase ls provided
between designated hot rolls and the next succeeding cold roll,
Drawing is assisted by heating the filaments or portions thereof
at fluted roll 25 and when desired at smooth roll 23, Since
roll 23 is a smooth cylindrical roll, uniform drawing is obtained
between rolls 23 and 24, Roll 25, however, has grooves running
along its surface in the axial direction, Segments o~ the yarn
which touch the hot surface of the roll between grooves are
drawn additionally but those segments suspended over the grooved
portions are not drawn additionally to a significant degree, The
filaments leaving roll 25 have alternating highly oriented and
less oriented segments along their length, The ribbon of segment
-- 10 --
105;~S18
drawn filaments passes from roll 27 to guide 28, The filaments
are electrostatically charged upon passing across the target bar
of a corona charging device 29, such as the devic~s described in
U.S.Patent 3,163,753, The ribbon of electrostatically charged
continuous filaments is sucked into the entrance orifice of slot
~et 30 (which is of the type shown in Figure 6 of U.S.Patent
3,563,838) and issues from the slot jet exit for deposition on
moving belt 32. Figure 2 is a view taken from the upstream end
of the collecting belt 32. The sides 41 of the belt may, of
course, be much farther apart when multiple ~ets are used. As
shown in Figure 2, the ribbon of filaments 31 is deposited as
an X-layer. A pulse of air is supplied at the jet exit alter-
nately from one side of the moving ribbon of filaments and then
from the other to de~lect the ribbon back and forth, thereby
deposlting filaments predominantly aligned in the cross-machine
direction.
The general arrangement of multiple forwarding ~ets
over the collecting belt may be seen in Figure 3 which shows
four slot ~ets each forwarding a ribbon of filaments 31 to the
porous collecting belt 32 moving in the direction shown by the
arrow 40. The two upstream jets 30 are placed with the widest
dimension of the slot oriented across the width of the collect-
ing belt. The two downstream ~ets 34 are placed with the widest
dimension of the slot oriented in the machine direction 40. The
arrangement shown in Figure 3 is for depositing layers in MX
succession. ~or an MXM laydown, another set of ~ets is provided
downstream of ~ets 34 and these are oriented like ~ets 30. When
wider carpet backings are desired, a largernumber of ~ets is
provided across the wiath of the machine.
The arrangement of filaments within the product of the
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5~3
invention may be seen in Figure 3. Filaments in the M-layer 38
are arranged generally in the machine direction. However, a
portion of each filament is oriented in other directions because
of the necessity for turn-around at each end of the traverse
back and forth in the M direction. Similarly the filaments 39
in the X-layer are generally oriented in the cross-machine
direction but have portions of their length oriented in other
directions, Finally filaments are deposited downstream to form
another M-layer (not shown in Figure 3).
In preparing products of the invention, filaments of
relatively low denier are spun and drawn for depositing through
the jet streams oscillating in the machine direction and fila-
ments of high denier are spun and drawn for deposit by the jets
oscillating in the cross direction. In addition the filaments
which become the M-layers are segmentally drawn to a lesser degree
of molecular orientation than filaments for the X-layer. The
difference in denier per filament and molecular orientation for
the drawn segments in the M and X layers are obtalned by ad~ust-
ing the extrusion speed, and adjusting the draw ratios between
smooth rolls 23 and 24 and between grooved roll 25 and smooth
roll 26. The amount of molecular orientation in the binder por-
tion of the filament is primarlly determined by the relative
speeds of rolls 23 and 24. The percent binder for the M-layers
and X-layers is determlned by the ratio of the sum of the groove
widths to the total circumference of the grooved roll 25.
The deposited filaments are thermally bonded, prefer-
ably by passage through saturated steam using a bonder of the
type described in U.S. Patent 3,313,002. After bonding, a finish
is applied to avoid excessive fiber breakage during tufting.
The finish is preferably a polysiloxane as described in U.S. Pat.
3,322,607. Excessive shrinkage is avoided by restraining the
sheet through bonding. The degree of bonding affects the pro-
perties of the nonwoven product As bonding temperature increases
the neckdown of the tufted substrate decreases. At the same time
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increasing bonding temperature causes the tufted tongue tear
values to pass through a maximum value and then to decrease again.
A balance of neckdown and tu~ted tongue tear properties is needed
for carpet backing. Desirable products have 1 to 5% neckdo~m,
preferably 1 to 3%. Excessive application of mechanical pressure
should be avoided in using the bonder of U.S. 3,313,002 so that
fiber mobility will be maintained in the X layer. It is par-
ticularly important to avoid excessive mechanical pressure when
more than 20% binder is present in either of the outside M layers
since the binder when heated and pressur~zed tends to fuse into the
X layer thereby reducing fiber mobility. Fiber mobility is needed
for promoting high cut pile tufted tear strength, In design of
the sheet it should be understood that greater heat absorption
occurs in the M layer closest to the steam supply, For this
reason the fuzz ratings for the two sides of the sheet may differ
even though the same amount of binder is used in each M layer.
TEST METHODS
Directionallty, Tufted Tongue Tear, Percent Neckdown,
Binder Concentration and Matrix Fiber Denier, and Fiber Tenacity
are measured as described in U.S. Patent 3,821,062. Fiber tenacity
can also be determined on filament samples taken directly from
the ~ets and allowing for a 10% loss in tenacity in passing
through the hot bonding operation,
Tufted Tear Cut Pile
For this test, a cut pile carpet is prepared, using
bonded nonwoven fabric as the primary backing The carpet is
prepared with old worn needles The nonwoven fabric is lubricated
with about 2~ by weight of polymethylhydrogen siloxane A sample
of the lubricated sheet is cut from along its length (in the
machine direction) to form strips 8 inches wide (20.3 cm.), These
strips are mounted in a 5/32 gauge cut pile tufter (needles
spaced 0.156 inch (o.396 cm ) apart) such that one strip is
tufted over a ~ridth of 6 inches (15.3 cm.) by old needles (picked
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s~
at randOm from a supply o~ needles used in the trade for approx-
imately 1,000 hours), All needles are Eisbar 1259/350 with
0,125 inch (0.318 cm.) shanks, The nonwoven sheet is tufted in
the machine direction using a t~Jisted nylon staple yarn (2 ply
yarn made from singles with 2,25 worsted count) at 6.5 tufts/inch
(6,5 tu~ts per 2,54 cm,) to provide a cut pile carpet with 0,500
inch (1,27 cm,) pile height leaving 1 inch (2,5 cm~) for untufted
sheet on each side of the tufted portion, The tufted substrates
with 1 inch (2,54 cm,) selvage on each side are cut to prepare
samples 20,3 cm, long (machine direction), The tufted-tongue-tear
cut pile strength is then determined in the same manner as for
loop pile, i,e., by tearing along the machine direction,
Fuzz Resistance
This test is a modification of ASTM Standard D 1375,
Part C, Brush and Sponge Procedure, Samples are cut from the
bonded nonwoven fabric to form square specimens 25,4 cm, long in
the M direction and 25.4 cm, wide in the X direction, The speci-
mens are wrapped around flat galvanized steel specimen holders
which are rectangular in shape (10,8 cm, x 29,2 cm,), The slde
to be tested bares outward, The holders are covered with 100
grit sandpaper to prevent æpecimen slippage during testing and
the specimens are fastened to the holders by magnets, The total
weight of the steel strip and magnet is 550 ~ 5 grams. The
specimens are then mounted face down on the upstanding bristles
of the Pilling Tester, and the fuzz generating brush is run for
10 seconds underneath the specimens, The next step in the ASTM
procedure, i,e,, subjecting the fabric to a circular rubbing
action with a sponge to roll the free fiber ends into pills, is
eliminated, The appearance of the fabric is then evaluated by
comparison with visual standards, A brush fuzz rating from 1 to
5 is given with 1 being extremely fuzzy and 5 being essentially
free of fuzz. Products of the invention have relatively high fuzz
resistance compared to prior art products at the same level of
neckdown,
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lOS'~5~8
Percent Optical Cov_
This is a photometric test for determining the cover-
ing power of test ~abrics. Separat~ measurements are made of the
amount o~ light reflected from a white background, black back-
ground, the test fabric in contact with the white background,
and the iden~ical section o~ test fabric in contact with the
black background. Measurements are taken on at least five
different sections of each test fabric. A commercially available
device is used, consisting of a search unit (including a light
source, optical system, and photocells) connected by cable to
an indicating meter, power supply, and controls. Percent optical
cover is calculated using the reflectance measurements according
to the following equation: ~
Percent Optical Cover = /1 _ FWB FBB x 100
~ RWB - RBB /
where RWB = reflectarlce~rom white background (calibrated to be
100 on the indicating meter).
RB~ = reflectance from black background (calibrated to
O on the indicating meter).
RFWB = reflectance from fabric on white background.
RFBB = reflectance from fabric on black background.
Products of the invention have relatively high optical cover
at a given basis weight compared to prior art products. For
comparison the fabrics must be made from filaments having the
same color depth and hue.
Examples 1-5
An experimental apparatus, similar to the equipment
described in Figures 1 and 2, is used to prepare five nonwoven
fabrics of the invention. The filament spinning, drawing, and
depositing operations for each example are given in Table I.
105'~
the filaments contain highly dra~n matrix segments and les~
drawn binder segments, as a result of pas~age over grooved roll
25, whlch is heated to 135-140C.
In all the examples, the amount of web defl¢c~lon is
adJusted to provide a prescribed percent by weight of fiber in
the ~ and X layers in the central areas used ror sampllng. The
sampling areas were at the center of ~heet width and included
representative portlons Or each of the depo~ited M and X layers.
Portions of the sheet near the side edges were not used ~or
sampling. The construction o~ the flve nonwoven sheets is sum-
marized in Table II. Propertles Or the bonded sheets alone and
when used a8 primary carpet backings are given in Table III.
In all the examples, filaments are melt-spun from poly-
propylene havlng a melt flow rate o~ 3.2 + .4 accordlng to ASTM
Method D 1238-65T and contalnlng o.o68 to 0.078% carbon blAC~
pigment. The re~ultlng fllaments are gray in shade and equiva-
lent in depth and hue. Nonwoven fabrics with an MXM-layer con-
structlon are produced by depositing the melt-spun polypropylene
fllaments from three splnnerets arranged in tandem o~er the
collectlng belt. ~ach spinneret feeds a ~eparate ~et. The output
o~ each spinneret 18 depo&ited in successlon on a moving belt.
Flrst an M-layer is applled at the upstream end of the collecting
belt, then an X-layer, and then another M-layer. m e belt speed
is ~d~usted to g~ve products with the unit weight indicated in
~able III.
As shown in Table II each of the nonwoven webs ls
constructed of hlgh denier rila~ents ln the X-layer and low
denier rilaments in the M-layers. The filaments in the X-layer
have higher orientation than the filaments in the M-layers.
The high orientatlon is reflected in the high ~ilament tenacity.
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.
~szs~
The propertles o~ carpet b~ckings and carpets made from
the webs of Table II are sho~n in Table III. The products
de~cribed in Table II are bonded by pa~sing through the steam
bonding equlpment described in U.S. Patent 3,313,002. The
collected fllamentæ and the collecting belt pas~ dlrectly through
this bonder from the laydown area. The ~team temperature in the
bonder læ ad~usted to produce product~ ~ith a neckdo~n of less
than 5%, preferably less than 3%. Neckdown i8 reduced by using
higher te~peratures. However, the temperature læ kept low
enough 80 that tu~ted tongue tear 6trength for the subsequently
made loop carpet 18 stlll at least 18 lbs.//oz./yd.2 (0.24 kg.//g.
/m.2). The temperature~ used in these examples are in the range
148 to 152C. (When faster belt speedæ are used, higher temp-
eratures are required for adequate bonding.) It wlll be noted
ln Table III that the resultant carpet backings have a fuzz
ratlng Or at least 3.0, and preferably at least 4.0 on at least
one surface and with a cover of at least 77~, with unlt welghts
of 2.9 to 3.7 oz./yd.2 (98 to 125 g./m.2).
m e carpet backing6 of Table III are used to prepare
loop plle carpets and cut plle carpets as specified in the test
methods. These nonwoven fabrlcs of the invention have high
tufted tear strength in loop pile carpets. In additlon these
backings are useful for making cut pile carpets and the bac~ings
are les6 sensitlve to the quality of the tufting needles. Table
III æhowæ that the tufted cut plle carpets prepared with old
needles have tu~ted tear strength above 45 lbæ. (20.4 kg.). m 1
feature comblned with high fuzz resi6tance and high cover make
the backing materlal a very uæeful product.
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., ,~j,
. ~.~ ", . .
TABLE I
PROCESS CONDITIONS 0~ TH~ EXA~PLES
Example No. 1 2 3 4 5
Surface Speed of Roll 26
M-layers, metcrs/~in, 660 660 505 505 660
X-la~ers, meters/mi~, 537 645 537 495 537
Draw Ratio of Drawn ~egments(a)1 8 1 8 - 8 1,8 1.8
Break Elongation of Undrawn Segments(b)
Notes
(a) The draw ratio is calculated from the ratio of the
surface speed of roll 26 to the surface speed of roll 22.
~ b) The average elongation at break is determined on
heavy denier segments cut from filaments deposited on the belt
before bonding.
(c) 200 filaments are collected in each M layer per
spinneret; 150 filaments are collected in the X-layer per spin-
neret, except in Example 2 where only 100 filaments are collected
in the X-layer per spinneret.
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lOS'~S18
TABLE II
NONWOVEN WEB CONSTRUCTION OF THE EXAMPLES(a)
Example No. 1 2 3 4 5
Matrix Filament Denier
M layer 14.2 13.3 11.5 14.5 14.0
X layer 32.5 47.1 35.3 33.6 33.6
M layer 12. 8 12.0 14. 5 14.4 10. 3
Matrix Filament Tenacity(b)
M layer, grams/denier 2.7 2. 4 2. 6 2. 4 2. 8
X layer, grams/denier 3.7 3.7 3.5 3.6 3.6
M layer, grams/denier 2.2 2. 4 2.7 2.9 2. 8
Weight % Binder in Layers(C)
M layer 12 12 12 12 32
X la,yer 12 12 12 23 12
M layer 12 12 12 12 32
Directionality Values(d)
MD/45 2.0 2.8 2.6 2.4 2.6
XD/45 2.9 2.9 2.6 1.5 2.8
(MD + XD)/45 4.9 5.7 5.2 3.9 5.4
Notes
(a) In each example 25% of the total fabric weight is in each
surface M layer and 50% of the total fabric weight is in the X
layer.
(b) Filament samples were taken from the jets or the bonded webs.
Tenacities obtained on samples from the jet were reduced by 10%
to estimate the effect of bonding.
(c) Calculated as the weight percent of undrawn segments by the
ormula: % undrawn = Total arc length of grooves x 100
Total circumference of grooved roll
(d) Measured by the Randometer method.
-- 19 --
105'~S18
TABLE III
PROPERTIES OF BACKINGS AND CARPETS OF THE EXAMPLES
Example No. 1 2 3 4 5
Nonwoven Backing
Unit Weight~ oz /yd 2312753127 2 9 302 31i95
Cover, ~0 79 80 0 81 77
Fuzz Rating of ~-Layers
First layer exposed to steam 4.7 4.6 5 0 5,0 4 4
Other M-layer 4.5 4 1 3.5 4.0 3.3
Loop Pile Carpet 103 94l 7346 7385 146
lbs //oz /vd,~ 28 24 26 26 29
kg.j/g /m 2 o.38 0 32 0.35 0.34 0.39
~ Neckdown 1.7 1 8 1.5 1.7 2
Cut Pile Carpet made with
Worn Needles, Tufted
Tear Strength, lbs. 524 4261 64 24 23
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