Note: Descriptions are shown in the official language in which they were submitted.
~29721!3V
TUFTED CARPET
Background of the Invention
Field of the Invention
The invention relates to tufted carpeting
material, particularly carpeting material useful as an
entry mat to remove dirt and water from shoes.
Background Art
Various devices have been employed at the
entryways of buildings to reduce or remove the accumulation
of various solid materials (hereinafter referred to merely
as "dirt") and water typically found on the shoe soles and
other pedestrian surface contacting parts of the shoe such
as the heel (all of such parts hereinafter being referred
to as the "shoe soles") of persons entering the building.
Such devices typically include a mat which provides a
brushing or wiping action against the shoe sole.
Such mats are generally fibrous or fabric in
nature to provide the desired frictional surface and wiping
action. Most fabrics or fibrous mats are not, however,
completely satisfactory because they have a very limited
capacity for storage of removed dirt and water and most are
not particularly conducive to the rapid evaporation of
water. They require frequent shaking and washing to
rejuvenate the mats for subsequent uses~
Attempts have been made to provide floor mats
which have a greater capacity for the storage of
accumulated dirt, but these have generally been somewhat
less than satisfactory. For example, lengths of solid
materials such as edgewise oriented pieces of metal or
segments of cut up automobile tires have been linked
together, leaving spaces therebetween, to provide for the
storage of dirt and other debris. Such mats, however, are
not satisfactory because, besides being poor water
absorbers, they leave the dirt removed plainly in view and
they also require that the dirt be collected and removed
.
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after the mat is displaced since such mats generally have
no bottom layer.
Some fabric or fibrous mats are unattractive
and/or fail to provide a luxuriant underfoot surface. The
more attractive and luxuriant mats are generally formed of
very dense carpet pile, providing a surface with only a
limited capacity for the storage of dirt and a structure
from which water will be evaporated slowly.
Such carpet mats typically consist of a heavy
backing attached to keep the mat in place upon which are
deployed tufted fibers typically on the order of 6 to 15
denier per filament, a common fiber size for conventional
carpeting material. While these fibers look good and have
a pleasing texture when used in carpet, a mat of such
conventional carpet fibers presents a rather closed surface
which has little if any space to store and conceaI dirt.
Such a shortcoming gives rise to a phenomenon known in the
entryway mat business as "retracking".
Retracking occurs when removed dirt on the
surface of a mat such as tufted carpet with insufficient
dirt storage space remains on the top of the mat and is
picked up by the next person walking over the mat, causing
the dirt to move further along on the mat until it is
eventually carried into the building.
while mats containing larger denier fibers, such
as those formed of coir (sometimes called "coco") fibers,
fibrillated polypropylene film or large denier vinyl
fibers, provide a sufficiently open mat to store dirt
between such fibers, the large denier fibers are not very
effective in absorbing and evaporating water.
U.S. Patent No. 4,045,605 (Breens et al)
discloses a carpeting material which includes pile or tuft
fibers comprising 75 to 98~ by weight of conventional
carpet fibers and 2 to 25~ by weight of stiff fibers or
filaments arranged, not to provide openness to store
removed dirt, but act as dirt scrapers. The stiff fibers
1~97~:~t0
~3--
are not crimped. The conventional carpet fibers are less
than 30 d~citex per filament (about 27 denier) while-the
stiff fibers or filaments are of from 30 to 300 tex (about
270 to about 2700 denier). (The term "denier" refers to
the weight in grams for a 9,000 meter fiber while the term
"tex" refers to the weight in grams for a 1,000 meter
fiber. Decitex is one-tenth of tex. A 0.11 tex fiber, or
1.1 decitex fiber would be 1 denier.) While sreens et al
indicate that the stiff fibers may be fed in with each row
of conventional pile or tuft yarn or in alternate rows or
less frequently, using a conventional tufting machine or
carpet loom, Breens et al also contemplate one or more rows
of tufts of conventional carpet yarn followed by a row of
stiff fibers or filament. Such an arrangement would not
provide sufficient openness for the storage of removed
dirt.
Summary of the Invention
The present invention provides a tufted carpet
mat which is particularly suited for pedestrian traffic.
The mat of the invention may be advantageously used at the
entryway of a building to wipe wet and/or dirty shoe soles.
The mat of the invention overcomes many of the deficiencies
noted above, providing a luxuriant, attractive, durable
surface capable of wiping shoe soles, receiving, obscuring
and holding therein dirt removed from shoe soles, wiping
water from the shoe soles and facilitating evaporation of
water.
Generally, the tufted carpet mat of the invention
is comprised of a backing having thereon a plurality of
tufts of fine denier fibers and a plurality of stiff,
textured or crimped, coarse denier fibers. The tufts of
coarse denier fibers may be mixed, either randomly or in an
ordered pattern within tufts of fine denier fibers. One
way of accomplishing this is by overtufting the coarse
denier fibers onto a backing which already bears or is
-4-
simultaneously tufted with the fine denier fibers to
provide tufts of coarse denier fibers mixed with the tufts
of fine denier fibers. The relative proportion of tufts of
crimped, coarse denier fibers to tufts of fine denier
fibers should be adjusted to provide sufficient wiping
action and water absorbency, thought to be a function
mainly of the tufts of fine denier fibers, and sufficient
openness to collect and obscure collected dirt, the latter
being a function mainly of the tufts of crimped, coarse
denier fibers. Preferably, the tufts of fine denier fibers
are in areas separate from areas of the tufts of coarse
denier fibers~ Most preferably, the areas of tufts of fine
denier fibers separate the areas of tufts of coarse denier
fibers as in a checkerboard pattern or a pattern of
alternate stripes of each area. Each of the areas is
preferably at least about 2 mm in its smallest dimension,
that being the approximate width of one row of tufts of a
typical crimped, coarse denier fiber, to provide an
adequate space for storage of dirt, but no more than 500 mm
in its smallest dimension so that the shoe sole of a
pedestrian will always contact both areas with each step.
The preferred carpet has a checkerboard pattern with the
- areas being shaped substantially as rectangles, each area
preferably being about 2 to 50 cm2 in size.
The fine denier fibers preferably are about 15 to
50 denier per filament (dpf) and the coarse denier fibers
are preferably about 150 to 500 dpf. The total weight
ratio of fine denier fibers to coarse denier fibers in the
tufted carpet is preferably on the order of 1:3 to 3:1.
The carpet preferably has a tufted pile face weight of at
least about 600 grams per square meter and a pile height at
least about 0.5 cm.
The preferred pattern of fine denier and coarse
denier areas is a checkerboard pattern or stripes with an
area of coarse denier fibers being adjacent to an area of
fine denier fibers in the checkerboard or the stripe
1297Z~O
pattern. The areas of tufts or fine denier fibers and the
areas of tufts of coarse denier fibers may be of the same
height, but preferably the areas of tufts of coarse denier
fibers are of a lower height than the height of the tufts
of fine denier fibers to provide depressions for collecting
dirt directly over the tufts of coarse denier fibers. The
collected dirt will then be received in the open spaces
provided within the tufts of coarse denier fibers because
these fibers are crimped. Crimping endows the areas
containing the tufts of coarse denier fibers with a very
open structure which is capable of easily receiving and
obscuring dirt once it enters therein. The tufts of fine
denier fibers provide a wiping action against the shoe sole
which removes dirt therefrom.
The preferred carpet mat of the invention
includes tufts of cut fine denier fiber and tufts of
looped, crimped, coarse deneir fibers. While the coarse
denier fibers may be cut, it is preferred that they be
uncut, thereby making the carpet mat easier to clean.
The fine denier carpet fibers are preferably
nylon, acrylic, regenerated cellulose, wool, polyester,
cotton or polypropylene fibers, or a mixture of two or more
of these. The stiff, coarse denier fibers are preferably
nylon, polyester, or polypropylene.
Detailed Description
The tufted carpeting of the present invention may
be produced by conventional carpet making equipment. A
useful commerically available carpet making device may be
J A 30 obtained from Tufting Machine Division of TUFTCO
Corporation of Chattanooga, Tennessee. Tufting is a
process whereby tufts of yarn are inserted into a backing
material, called a "primary" backing, typically formed of
woven or non-woven fabric. Yarn, as is well known, is a
collection or a bundle of crimped fibers of the appropriate
size, in continuous or discontinuous lengths. The tufts of
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yarn are inserted by vertical, reciprocating needles
similar to conventional sewing machines. A conventional
tufting machine is like a giant sewing machine having
hundreds of threaded needles held in a needle bar over a
bed plate across the width of the machine. The needles
receive the yarn from large beam6 or cones arranged in
racks or a creel. Yarns of the coarse denier fibers are
fed to spaced collections of needles on the needle bar
which are spaced to produce spaced areas of tufts of the
coarse denier filament. Yarns of the fine denier fibers
are fed to needle collections on the needle bar which
occupy the space between the needles receiving the coarse
denier flbers to produce tufts of fine denier fibers
between the tufts of coarse denier fiber, usually to cover
the carpet surface with tufts to provide a continuous
tufted area of separated areas of tufts of coarse denier
fiber and separated areas of tufts of fine denier fiber.
The yarns are tufted on the primary backing
typically in side by side rows usually with at least two
rows of tufts of the coarse denier fibers being deployed
between rows of the fine denier fibers. The simplest
structure to produce is a matting with alternate stripes of
- tufts of coarse denier fibers and fine denier fibers with
stripes in straight lines along the entire length or width
of the primary backing.
An alternative method involves forming an initial
collection of tufts, much as one would do to produce a
striped pattern, but then shifting the needle set by
employing a shifting bar to displace the row, typically
displacing it about two tufts from its original path,
starting a new striped pattern in the displaced location,
then, after at least two tufts are made in the new
location, shifting back to the original striped path, and
repeating this shifting back and forth to produce a
checkerboard pattern. Other variations are possible to
obtain the tufted areas.
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While it is possible to use a conventional carpet
tufting machine to make a tufted carpet having alternate
stripes of tufts of the coarse denier fibers and the fine
denier fibers, such a tufting machine usually requires some
alteration to make it suited for use to make a tufted
carpet according to the present invention with a
checkerboard pattern. This may be mechanically
accomplished by the addition of a shifting cam. The
shifting cam displaces the needles from an original tufting
path to a path which is displaced from the original path,
usually one or two tufts on one side or the other side of
the original path, to make the checkerboard pattern.
The primary backing into wh~ch the yarns are
inserted is usually supplied in roll form, typically
located in front of the machine. Spiked rolls are
typically positioned on the front and back sides of the
tufting machine draw the primary backing over the bed plate
and through the machine. The speed of the spiked rolls
controls the number of stitches per unit of length. Moving
the primary backing slower produces more stitches per unit
length while a faster rate produces fewer stitches per unit
length.
Typically, located below the bed plate of the
tufting machine are looper and knife combinations which
-25 pick up and hold momentarily the yarns carried by the
needles. The loopers work is timed with the stroke of the
needles. ~hen tufting cut pile, the looper and knife
combinations hold and cut the yarns in a single operation.
As the backing advances through the machine toward the cut
pile loopers, the yarns picked up from the needles are cut
with a scissor-like action between the back of the looper
and knife cutting against the edge of the looper. Except
for the selection of the type and the appropriately siæed
fibers and the production of tufted carpet with separate
areas of tufts of coarse denier fibers and areas of tufts
of fine denier fibers, the tufting equipment and process
are well known in the art.
~Z97280
The coarse denier fibers are crimped to give the
area containing these coarse denier fibers sufficient
openness to receive and hide dirt and debris. The coarse
denier fibers are used in the process of making the tufted
carpet of the invention as yarns. Such yarns are made up
of a plurality of crimped coarse fibers, typically with
about 10 to 20 fibers per yarn. Crimping should be
sufficient to give the fiber sufficient thrae-dimensional
structure to form a tuft which can have sufficient space to
receive dirt and sufficient entanglement of fibers to hide
or obscure dirt within the area of tufts of coarse denier
fibers. Crimping by conventional means, e.g., stuffer box,
produces adequate results. Conventional tufting machines
usually require that the coarse yarns be made up of
continuous fibers for processability.
The fine denier fibers may be made of filaments
which are either continuous or staple in yarn sizes that
are commonly used to make conventional tufted carpet. The
fine denier fibers are usually textured. Such conventional
carpet yarns are typically on the order of about 6,000
denier with about 200 to 300 fibers per yarn.
The face weight is determined by yarn spacing (or
machine gauge) as well as tuft length (pile height, yarn
denier and stitch rate). If the pile height is too high,
the fibers tend to lay over on themselves and could
interfere with the dirt storage capacity. A pile height
which iB too high may also provide a tripping hazard. If
the fiber or pile height is too low, the dirt hiding
capacity is diminished. If the stitch spacing is too
tight, the tufted carpet may not have sufficient openness
for tha storage of dirt.
Tufted pile height of at least 5 mm is preferred
for adequate dirt hiding capacity and the tufted pile
height should preferably not exceed 15 mm. The most
preferred tufted pile height is on the order of 9 to 15 mm.
Cleaning is also easier if the pile thickness is less than
15 mm.
~Z97Z8V
_9_
The primary backing i5 fabric which may be woven
or non-woven and may be formed of natural or synthetic
fibers. Preferred materials for forming the primary
backing include the materials that are customarily employed
for conventional carpet backing including, for example,
natural fibers such as those made of jute or cotton, and
synthetic fibers preferably those made of polyester or
polypropylene. The preferred primary backing weight is on
the order of 135 g/mZ. The fibers or filaments of the
primary backing may be formed of slit film, extruded
filaments or other conventional fibers formed in a
conventional manner by any of a variety of processes. The
primary backing may have needletacked to it a non-woven mat
to provide a locking affect for the tufts and to prevent
the backing material from unraveling. Such backings are
well-known to those skilled in the carpet making art and
this description is only given for purposes of illustration
and to indicate that such conventional primary backings are
useful in producing the tufted carpet of the present
invention.
The tufted carpet of the present invention
preferably includes a secondary backing which provides
weight or body to the carpeting material to prevent it from
being displaced as it is being walked over. The secondary
backing is formed of conventional materials known for this
purpose. The preferred secondary backings include those
made of vinyl plastisol, polyurethene, rubber latex and
similar materials. The secondary backing may be foamed,
patterned such as in a waffle pattern, or ribbed. The
secondary backing may also be filled with materials
conventionally used in such backings for carpet mattings.
The tufts may be formed on the backing without
utilizing à conventional tufting carpet machine. One way
of forming the tufts in this manner is described in U.S.
Patent No. 3,943,028.
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Examples
The invention is futher illustrated by the
following examples, all parts are by weight unless
otherwise specified.
~xamples 1-4
A conventional straight stitch cut pile tufting
machine available from TUFTCO Corporation having an 9 to 13
mm pile height capability having a hydraulic shifting
needle bar so as to produce a checkerboard carpet tuft
pattern was used. A "square" tufting stitch with a stitch
spacing of 5 mm was made in a 135 g/m2 woven primary
backing formed of woven polypropylene slit film filaments
having needletacked to it a polypropylene non-woven web.
This primary backing is available under the trade
A designation "Polybac'~ FLW style 2483 from Amoco Fabrics
Company. A 7900 denier yarn of fine denier fibers was
formed of 37 dpf continous polypropylene filaments and a
6500 denier yarn of coarse denier fibers was formed of
crimped 300 denier polypropylene fibers, providing a weight
ratio of coarse 300 dpf fibers to 37 dpf fine fibers of
about 45:55.
The tufting machine needles were threaded in an
"AAB~" arrangement wherein two adjacent needles were
threaded with the 37 dpf fiber yarn, the next two needles
with the 300 dpf fiber yarn, and repeabing this sequence
throughout the length of the needle bar. Knives were fixed
on the loopers to make a cut pile fabric.
Example 1 was a carpet sample made without
shifting the needle bar so a striped pattern was obtained
with alternate pairs of rows of the two fibers.
Example 2 was made in the same manner as Example
1 except the needle bar, after initially stitching 7
stitches, was shifted two spaces away from the initial
stitch path, stitching 7 stitches, shifting two stitches in
.
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the opposite direction of the initial shift, and repeating
this stitching and shifting pattern to produce a
checkerboard pattern of slightly elongated rectangles.
Control example 1 was a control carpet containing
only fine denier 37 dpf fibers and made similar to the
process described in Example 1.
Control example 2 was also a control carpet
containing only coarse denier 200 dpf fibers and made
similar to the process described in Example 1.
The face weight of Examples 1 and 2 and Control
examples 1 and 2 varied from 750 to 1000 g/m2, and the pile
height was 9.5 mm. Each of the carpet examples described
above was backed with a 2700 g/m2 filled vinyl plastisol as
is commonly used on such walk~off mats. This plastisol
consisted of about 32~ mixed plasticizers, 36~ vinyl
acetate/polyvinylchloride copolymer, 28~ fillers and small
amounts of surfacntants and pigments. The plastisol
secondary backing was formed by coating the plastisol on a
carrier belt, laying and forcing the primary backing side
of the into the liquid plastisol and fusing the plastisol
at 150C for about 10 minutes in a heat air oven.
Control example 3 was a commercially available
walk off mat which consisted of a 50 dpf polypropylene
fiber tufted carpet having a face weight of about 1000 g/m2
and a 2700 g/m2 secondary flexible rubber-like backing
which was commercially available under the trade
A designation Crown ~Tuff~n Tidy" and sold by Ludlow
Composites Company.
Water Absorption Test
Each of the example carpets were tested to
determine the amount of water each would absorb from the
shoe sole of the test foot in a Water Absorption Test.
The test device was originally built as a wear
tester for deck covering according to Mil-D-16651D. The
test device includes a 380 mm diameter horizontal turntable
i2~7~80
-12-
which is rotated at about 23 revolutions per minute beneath
a vertically moveable shaft with its longitudinal axis
deployed 130 mm from the axis of rotation of the turntable.
Affixed to the end of the shaft closest to the surface of
the turntable by two recessed bolts is a 50 mm diameter
"foot" made of 3 mm thick tanned shoe sole leather. AS the
turntable rotates, the shaft lifts the foot approximately
12 mm from a rest position above the turntable surface
whereupon it is released to drop back or "step" on the
turntable surface at the rate six times per revolution or
138 times per minute. The combined weight of the shaft and
foot was 1.7 kg. On the turntable surface are mounted and
restrained two split annular carpet samples, each defined
by a half annulus with a 400 mm outside radius and a 130 mm
inside radius. The two half annuli are clamped to the
turntable by an inner retaining ring and a thin metal strap
which bridged the gap between the half annuli. One of the
half annuli carpet samples is fully saturated with water to
provide a wet surface from which the shoe will pick up
water. The other half annulus is the test sample which is
weighed dry prior to the test.
The half annulus sample which is saturated with
water was available from the Minnesota Mining and
Manufac~turing Company under the designation All Weather
"Nomad'~mat. Water is added to this mat to fully saturate
it until water is observed at the surface of the mat. The
equipment is tested to determine adequate performance by
using as the other half annulus a test carpet another
sample of All Weather "Nomad" matting. The equipment is
run for 100 revolutions or cycles whereupon it was stopped,
additional water is added to the saturated mat, and this
sequence repeated, adding additional water after each 100
cycles until 500 cycles have been completed. The initially
dry test sample is then reweighed, its dry weight is
subtracted from its wet weight and the weight in grams
reported. The water pickup for the All Weather "Nomad" mat
~ c- ~Rk
lZ972t30
typically is on the order of 62.5 to 66.5 grams for an
average of 64.5 grams with the standard deviation of about
2 grams.
Water adsorption test results for Examples 1-2
and Control examples 1 and 2 are given in Table I.
Table I
Example Water Absorbed (g) Face Weight g/m2
1 (stripe) 92 915
2 (check) 119 750
Control 1 92 915
Control 2 56 815
Control 3 78 1020
It was surprising to note that the amount of
water absorbed by the carpet of the invention, Examples 1
and 2, was no less than Control example 1 and greater than
Control Example 2. This was completely unexpected since it
was thought that the amount of water absorbed would be
closer to the average weight of the water absorbed b-y
Controls 1 and 2.
-
Dirt Removal Test
Te6ting for dirt removal and dirt trapping was
done by measuring the amount of dirt left on the mats by
people walking through a 1.8 m long by 0.9 m wide tray,
containing 12.6 kg sand, onto a 1.5 m long by 0.9 m wide
test mat. After wallking on the test mat, the people
walked on buffer mats to thoroughly clean the shoes before
repeating walking into the tray of sand, onto the test mat,
etc. In this test, the same 20 people repeated the cycle
25 times. At the conclusion of the dirt removal test, the
test mat was weighed, and weight compared with test mat
weight prior to the test to determine dirt stopped.
Results of this test are given in Table II.
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Table _
Example ~irt Stopped (g)
1 908
21078
Control 1 936
Control 2 985
Control 3 936
Examples 3-6
Control Examples 4 and 5
In these examples, a designed experiment was
conducted to determine the effect on water removal
capabilities of varying the ratio of large denier and small
denier fibers.
Examples of tufted carpet were prepared by
methods used in Example 2, except the weight of each yarn
was varied. Table III summarizes the results.
Table III
.
Yarn AYarn B Water Dirt
Ex. (25 dpf)(300 dpf) Face Wt. Absorbed Stopped
No. Total %Total % g/m2 (grams) (g)
3 7200 d 50 7200 d 50 985 130 22
4 3600 d 33 7200 d 67 745 129 21
5400 d 49 5700 d 51 815 136 25
6 7200 d 62 4300 d 38 850 115 24
C-4 7200 d 100 ---- - -- 91S 92 19
C-5 ---- - -- 7200 d 100 745 52 20
This chart shows that ratio of fine and coarse
fibered yarn from about 1/3 to 2/3 to 2/3 to 1/3 are more
effective than either all fine or all coarse denier fibers.
~Z9721~0
-15-
Examples 7-10
In order to learn the effect on mat performance
of the large denier fiber in the mat, a series of tufted
mats was prepared similar to that given in Example 1 and
according to the specifications shown in Table IV.
Table IV
Small Denier Fiber Large Denier Fiber Face Water
Ex. Fiber Yarn Total Fiber Yarn Total Weight Absorbed
No. Size Denier ~ Size Denier ~ (g/m ) (grams)
7 37 d 8100 56 170 d 6000 44 950 83
8 22 d 4300 45 273 d 6500 55 815 92
9 37 d 8000 52 300 d 7400 48 915 92
22 d 5400 52 410 d 5000 48 745 76
The last column shows the effect on the water
absorbing properties of this variation. A preference for
large denier fiberc in the region of 300 dpf is noted.
Example 11
Control Example 6
Control Example 6 is made according to the
disclosure of ~reens, U.S. Patent No. 4,045,605. Control
Example 6 was made following the specific example disclosed
by Breens except using the fibers identified below, which
fall within his teaching. The specific fibers disclosed by
Breens were unavailable. This was done in order to compare
the performance of a carpet of uncrimped coarse denier
fibers blended with fine denier fibers to a carpet of the
invention (Example 11) which consisted of areas of crimped
coarse denier fibers and of fine denier fibers. The types
of fibers and carpet face weight and pattern are set forth
in Table V, as are the water absorbency test results.
~.Z97~30
-16-
Table V
Ex. 22 dpf 300 dpf Eace Wt.
No. Yarn Yarn g/mZ Pattern Water (g)
C-6 75% 25% 815 Uniform/Blended 87
11 67% 33% 745 Same as Ex. 2 129
Control example 6 was prepared using uncrimped
300 denier coarse denier filaments uniformly blended into
the 22 dpf yarn. Example ll had fibers arranged in a two
stitch wide by 7 stitch long rectangular pattern as
described in Example 2. Even with the advantage of a
higher face weight for Control example 6, its water
absorption properties were much less than a carpet having
discrete areas of crimped coarse denier fibers according to
the invention.
Examples 12 and 13
Example 12
A carpet mat consisted of areas of looped tufts
of fine denier fibers and areas of looped tufts of crimped
coarse denier fibers. A 3/16 gauge tufting machine with an
in~line needle bar with loopers instead of knives was used.
The needles were threaded with 6000 denier textured yarn
composed of 25 dpf polypropylene textured fine filaments
(each tuft of fine fllaments being referred to by "A" ) and
600 denier textured yarn composed of 170 dpf polypropylene
coarse filaments (each tuft of coarse denier filaments
being referred to by "B") in an AAAA, BBB8 sequence. Eight
rows of tufts were produced in sequence on an original
path, each row having the AAAA, ss8s alternate sequence.
The needle bar was then shifted to displace each needle
path from the original path by two rows and a single row of
tufts produced. The needle bar was again shifted to
displace each needle path from the original path by a total
of four rows and eight tufts produced on the new path. The
~2972Ei0
-17-
needle bar was then returned to it~ original path in a
reverse sequence, and the same sequence repeated to produce
a checkerboard pattern of alternating rectangles 19 mm (3/4
inch) wide by 31.75 mm (1 1/4 inch) long of 25 dpf yarn and
S 170 dpf yarn. Pile height was controlled to give an
approximate 6.3 mm (1/4 inch) pile height and a 866 g/m2
(26 oz. per square yard face weight) of total fiber.
Example 13
Example 13 was prepared in exactly the same way
as Example 12 except the 170 dpf yarn was stitched at a
lower pile height, about 1.6 mm (1/16 inch) lower than the
25 dpf yarn. The resulting carpet had the same finished
appearance as Example 12 except the rectangles of the 170
dpf yarn were about 1.6 mm (1/16 inch) lower than the
rectangles of 25 dpf yarn. The carpet so produced was
passed under a reel type cutter called a tip shear which
was ad~usted to cu~ the looped tops of the 25 dpf yarn.
This created the plush type appearance in the 25 dpf
rectangles of a cut pile carpet.
Examples 12 and 13 and Control Example 7, a
commercially available tufted carpet mat consisting of 22
dpf polypropylene fibers, were tested for water absorbency
with the results being shown in Table VI.
_able VI
Example Grams Water Absorbed
12 101
13 lOS
30Control 7 73
This result clearly shows the superiority of
Examples 12 and 13 in the ability to remove and trap water.
~Z97~0
-18-
Examples lk to 26
Examples 14-26 describe the preparation of carpet
mats having looped tufts of crimped coarse denier fibers.
These carpet mats had excellent cleanability.
Examples 14-18
A mat according to the invention was made with a
high-low tufted loop configuration. ~ 5 mm (3/16 inch)
gauge tufting machine with loopers to catch the yarn from
the needles was threaded with a AAAA, BBs8 repeating yarn
configuraSion. The machine had a shifting needle bar and
was adjusted to shift four rows every six stitches. This
gave a pile carpet consisting of tufts of looped fine
denier fibers and tufts of looped crimped coarse denier
fibers having 100 x 150 mm rectangular areas. The tension
on the yarn was adjusted so that the fine denier yarn loops
were about 4 mm ~1/6 inch) higher than the coarse denier
fiber yarn loops. The loops of fine denier fiber were then
sheared using a conventional tip shear, giving a plush
appearance to the areas of carpet than have the fine denier
fiber tufts.
Yarn A, providing the fine denier fiber, was a
6000 denier yarn made of 25 dpf polypropylene fiber. Yarn
B, providing the coarse denier fibers, was the crimped
fiber identified in Table VII opposite the appropriate
Example number.
Table VII
Coarse Crimped Fibers
30Example Fiber Yarn Fibers Yarn
Number dpf Denier in Yarn Type
14 300 16 polypropylene
300 16 polypropylene
16 170 6000 polypropylene
17 5,0001 1 vinyl coated
polypropylene
18 300/222 2400 8 polypropylene
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-19--
1 A 30 mil diameter sheath-core filament with a 1,000
denier polyester core and a 4,000 denier polyvinyl
chloride sheath.
2 Air entangled combination of 8 ends 300 dpf and 110 ends
of 22 dpf to provide a 2400 denier yarn.
The sample6 were tufted in a woven polypropylene
primary backing and the resulting tufted mat was backed
with an 80 oz. vinyl plastisol backing.
Examples 19-26
Examples 19-26 were prepared by overtufting
coarse denier fibers onto a backing which was pretufted
with fine denier fibers.
rhese examples were made on a tufting machine
which had two needle bars arranged in a series. The first
needle bar was of 3 mm (1/8 inch gauge) arranged to provide
a cut pile carpet. The second needle bar was of 6.3 mm
(1/4 inch gauge) arranged to provide looped pile. The loop
pile needle bar was also arranged so it shifted to provide
a zig-zag pattern and the yarn fed to this needle bar was
controlled by individually controlled tension rolls so the
loop of coarse fiber was pulled to the primary backing so
that it was not vlsible when viewing the surface of cut
pile produced by the 3 mm (1/8 inch gauge) needle bar and
did not extend to the same height as the fine fiber cut
pile.
By selectively adjusting and varying the tension
on the 6.3 mm (1/4 inch gauge) loop yarn, a fabric was made
in which none of the loops of coarse denier fibers was
visible or in which every loop of coarse denier fiber was
visible.
The carpet mat of Examples 19-26 used a 3 mm (1/8
inch gauge) cut pile needle bar threaded with 300 denier,
25 dpf polypropylene yarn as the fine denier fiber. The
coarse denier fiber is shown in Table VIII. The coarse
~IZ97Z130
-20-
denier fibers were threaded in each needle of the needle
bar for Examples 19-21 and for Examples 22-26 in alternate
needles of the needle bar to give an effective 13 mm (1/2
inch gauge) loop threading.
Table VI I I
Example Fiber YarnFibers ~arn
Number dpf Denierin Yarn Type
19 170 6000 36 polypropylene
170 6000 36 polypropylene
21 170 6000 36 polypropylene
22 170 6000 36 polypropylene
23 170 6000 36 polypropylene
24 37 7000 190 polypropylene
5,000 ~- 1 vinyl coated
polypropylene
26 300/22 -- 118 polypropylene
20 Carpet mats made according to Examples 14-26 were tested
for their ability to trap and hold water according to the
Water Absoeption Test. The results of this test are
listed in Tables IX and X, respectively.
Table IX
Example No. Water Absorbed (g) Carpet Pattern
14 86 rows
113 4 stitches by 6
stitches, check
16 111 4 stitches by 6
stitches, check
17 101 4 stitches by 6
stitches, check
18 107 4 stitches by 6
stitches, check
Control 71 70 none
--2 1--
1 A commercially available tufted carpet mat consisting of
22 dpf polypropylene fibers.
From Table IX, it can be seen that a mat which
contains combinations of crimped, coarse and fine fibers in
discrete areas is preferable to a mat containing alternate
rows of the same fibers and a mat consisting only of fine
denier fiber. A preferred construction is Example 15 which
absorbs and traps 43% more water than Control 7, a tufted
22 dpf polypropylene carpet mat commonly used in the
industry today. This is quite unexpected since the larger
denier fibers, especially those of a hydrophobic polymer
such as polypropylene, would be expected to provide fewer
and smaller interstitial spaces for water to be wicked to
and stored.
Mats containing discrete areas, such as Example
15, absorb 31% more water than mats containing alternate
rows of coarse and fine fibers, e.g., Example 14.
In reviewing the data of Table IX, the
20 significantly improved water absorbing and trapping
properties i~ evident ln carpet mats made with looped pile
crlmped, coarse denier fibers in discrete area~ in
combination with fine denier carpet fibers of a size
conventionally used in carpet. Mats of coarse denier fiber
looped pile are preferred because they were easier to clean
as compared to mats of cut pile coarse denier fiber.
Table X shows that similar water absorbency
results can be obtained by overtufting loops of coarse
crimped denier fibers on carpet mats of fine denier fiber.
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Table X
Example Coarse Denier Water ~ Loops
Number Fiber Size (dpf) Absorbed ~g) Pattern Exposed
19 170 91 Pin-dot 80
170 103 Checks 25
21 170 88 Random 15
22 170 83 Plain 0
Control 7 70 -~
23 300 125 Checks 25
24 5,000 88 Pin-Dot 50
37 99 Checks 25
26 170 112 Checks 40
An analysis of data of Table X illustrates the
advantage of having loops of fiber randomly protruding
above a cut pile carpet for improved water absorption. In
addition, the data illustrates that larger fibers function
better than smaller, but that some benefit is obtained from
smaller loops as well.
Examples 19-26 show that there i6 more of a
benefit by having the coarse denier fibers in discrete
areas rather than being dispersed throughout the carpet
mat.
All the Examples made according to the present
invention had better performance than control carpet
samples consisting entirely of fine denier polypropylene
fibers such as is commonly used by the trade.
In sum, it has been found that incorporation of
looped pile coarse denier fibers in patterns with fine
denier carpet fibers produces a walk-off mat with superior
water absorbing and holding capabilities. It has also been
found that tufting loops of coarse denier fiber through a
fine denier cut pile carpet can significantly increase the
water absorbing and holding capability of a walk-off mat.
The present invention may be embodied in other
specific forms without departing from its spirit or
lZ~77~
essential characteristics. The described embodiments are to
be considered in all respects only as illustrative and not
restrictive. The scope of the invention is, therefore,
indicated by the appended claims rather by the foregoing
description. All changes which come within the meaning and
range of equivalency of the claims are to be embraced
within their scope.
