A stitchbonded nonwoven fabric which comprises a fibrous layer is reinforced in a first direction with bulkable thread and in a second direction with substantially inextensible thread, the reinforcing directions being at an angle of at least 50 degrees with each other, exhibits superior strength, resistance to splitting and repeated washability.

BACKGROUND OF THE INVENTION 
Field of the Invention 
This invention relates to a stitchbonded nonwoven fabric and a process for 
producing it by multi-needle stitching a nonwoven fibrous layer with two 
thread systems. More particularly, the invention concerns such a fabric 
and process for making it wherein one of the thread systems is a bulkable 
thread, the other is a substantially inextensible thread, and the threads 
are arranged in repeating patterns to form a drapable, durable, soft 
nonwoven fabric that is strong in both the longitudinal and transverse 
directions. 
Description of the Prior Art 
Nonwoven fabrics have long been used in a variety of applications. 
Unbonded, (i.e., not bonded) nonwoven fabrics most often have been used in 
applications that require little strength and durability. Such unbonded 
fabrics generally lack surface stability and often come apart when washed 
or laundered. To strengthen such fabrics, support layers often have been 
combined with the unbonded fabric. Strength has also been improved by 
bonding the fabric with a resin binder or binder fibers incorporated in 
the fabric. In addition to strengthening the fabric, bonding improves 
fabric stability and durability. However, bonding also makes the fabric 
stiff and boardy. Multi-needle stitching (i.e., stitchbonding) of unbonded 
nonwoven fabrics has also been used to increase fabric strength mainly in 
the direction of the stitching. 
Use of bonded and unbonded, bulked nonwoven fabrics in disposable swim 
wear, towels, wash cloths, training pants for infants, baby wipes, 
scouring pads, mattresses, cushions, sleeping bags and the like has been 
disclosed, for example, by Wideman, U.S. Pat. No. 4,606,964. Morman, U.S. 
Pat. No. 4,657,802, column 1, line 30, through Column 4, line 32, 
discloses a large number of elastic nonwoven webs for use as diaper 
components, filters, bandages, wearing apparel, and the like. Neither 
patent mentions stitchbonded fabrics. 
Multi-needle stitching machines, such as "Arachne", "Liba", or "Mali" 
machines (including Malimo, Malipol and Maliwatt machines) have been used 
to insert stitches into a wide variety of fibrous substrates. Such 
machines and some of the fabrics produced therewith are disclosed by K. W. 
Bahlo, "New Fabrics Without Weaving", Papers of the American Association 
of Textile Technology, Inc., pages 51-54 (November, 1965). Other 
disclosures of the use of such machines appear for example, in Ploch et 
al, U.S. Pat. No. 3,769,815, Hughes, U.S. Pat. No. 3,649,428 and Product 
Licensing Index, Research Disclosure, "Stitchbonded products of continuous 
filament nonwoven webs", page 30 (June, 1968). Warsop, U.S. Pat. No. 
4,306,429, discloses a novel stitchbonded fleece made with incompletely 
threaded front and back bars of a multi-needle stitching machine. Hughes, 
U.S. Pat. Nos. 3,329,552 and 3,649,428, disclose other stitchbonded 
fabrics made with two thread systems. However, none of these disclosures 
concern stitching of a nonwoven fibrous layer with bulkable thread. 
Multi-needle stitching of nonwoven fibrous layers with elastic thread (a 
type of bulkable thread) on one-bar stitchbonding machines is disclosed by 
Zafiroglu, U.S. Pat. No. 4,773,238, to make dust cloths. 
Although each of the aforementioned nonwoven fabrics have been used with 
some success, their utility could be significantly enhanced by 
improvements in their combination of strength, softness, washability and 
durability properties. An object of this invention is to provide such an 
improvement. 
SUMMARY OF THE INVENTION 
The present invention provides a stitchbonded nonwoven fabric made with two 
thread systems. The fabric comprises a nonwoven fibrous layer that is 
reinforced in a first direction with a bulkable thread which forms 
spaced-apart rows of stitches in the fibrous layer and is reinforced with 
substantially inextensible thread in a second direction which is at an 
angle of greater than 50 degrees with the first direction. The bulkable 
and the substantially inextensible threads are each multi-needle stitched 
through the nonwoven fibrous layer. In one embodiment of the invention, 
the reinforcement in the second direction is provided by inlay stitches 
Usually, the weight of the threads amounts to no more than 20% of the 
total weight of the nonwoven fabric, but for economy, often 2 to 10%, and 
sometimes as little as 3 to 5%. Suitable bulkable thread includes textured 
thread of polyester, nylon, polypropylene, or the like, and composite 
thread such as elastomeric yarn (e.g., spandex) in an extended state 
wrapped with inelastic nylon or polyester. Usually, the stitchbonded 
nonwoven fabric has a unit weight in the range of 10 to 300 grams per 
square meter, preferably 20 to 200 g/m2 The row spacing usually is in the 
range of 2 to 10 rows per centimeter, preferably 3 to 6 per cm. The stitch 
spacing usually is in the range of 2 to 15 stitches/cm, preferably 4 to 12 
per cm. 
Bulking of the bulkable threads (a) increases entanglement of the threads 
with the fibrous layer and enhances fabric stability and durability, and 
(b) causes gathering of the fabric, which results in a softer hand, 
improved drape, and decreased stiffness. 
The present invention also provides a process for making the 
above-described stitchbonded nonwoven fabric. In accordance with the 
process, a fibrous layer, weighing in the range of 15 to 150 grams per 
square meter, is fed to a multi-needle stitching machine equipped with a 
two-thread system. The first thread system is a bulkable thread which is 
stitched into the fibrous layer in parallel rows of stitches at a spacing 
in the range of 2 to 8 rows per centimeter and with the stitches within 
each row having a spacing in the range of 1 to 7 stitches per centimeter, 
preferably 2 to 5 per cm. The bulkable thread is stitched under sufficient 
tension so that, if the bulkable thread is a textured yarn, the textured 
yarn is essentially straight and, if the bulkable thread is wrapped 
elastomeric yarn, the wrapping thread is essentially straight. The 
bulkable yarn reinforces the fabric in a first direction. The second 
thread system is a substantially inextensible thread that is incorporated 
to provide reinforcement in a second direction which forms an angle of 
greater than 50 degrees with the first reinforcing direction. The 
inextensible thread can be incorporated by stitching within the same 
ranges of the row spacing and stitch spacing as in the first thread 
system. In other embodiments of the process, the inextensible thread, is 
formed as inlay stitches In each embodiment of the process, the stitching 
thread is under sufficient tension to maintain, after stitching, its 
original length. After the stitching operation, tension on the stitching 
threads is released, the bulkable threads are bulked and the area of the 
fabric is thereby reduced by 5 to 80%.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
The invention will now be described in detail with regard to a preferred 
stitchbonded fabric of the invention. The fabric is made from a fibrous 
layer and two thread systems, one thread system being of bulkable thread 
which provides reinforcement in a first direction, and the second thread 
system being of substantially inextensible thread which provides 
reinforcement in a second direction that is at an angle of at least 50 
degrees with the first reinforcement direction. 
Various starting fibrous layers are suitable for use in the present 
invention, such as batts of carded fibers, air-laid fiber batts, wood-pulp 
papers, lightly bonded and unbonded nonwoven sheets, and the like. The 
term "fiber", as applied to the fibrous layer, means staple fibers of 
textile denier, pulps, fibrids and the like. The fibers can be natural 
fibers or of synthetic organic polymer. The fibrous layer batts or sheets 
usually are supplied in wound-up rolls. If heavier fabrics are desired, 
two or more batts or sheets can be positioned upon each other to form the 
fibrous layer for subsequent stitching. However, a single batt or sheet is 
preferred for easier processing and lower cost. 
As used herein, the term "bulkable thread" refers to a thread or yarn which 
is "bulked" by being deformed out-of plane. The deformation is induced by 
releasing tension from the thread or by exposing the thread to chemical 
action, moisture and/or heat at a temperature of about 50 to 200.degree. 
C. 
The term "gathered" is used herein to describe the surface of the 
stitchbonded nonwoven fabric of the invention and to indicate that the 
final fabric area is no more than 95% of area of the fibrous layer from 
which it was made, (that is, the area before the fibrous layer was 
multi-needle stitched and/or bulked). 
In accordance with the process of the present invention, the stitching 
operation is performed with a conventional multi-needle stitching 
("stitchbonding") machine, equipped to handle two yarn systems. Malimo or 
Liba stitching machines are particularly useful. 
Substantially any strong bulkable thread is suitable as the stitching in 
the first direction. The bulkable thread provides a force that causes the 
fibrous layer to contract or gather when the thread is subjected to a 
bulking treatment (e.g., exposure to moisture, steam, heat, or chemicals). 
A particularly preferred bulkable thread is formed from spandex elastomeric 
yarn of high elongation and retractive power which has been wrapped with 
an inelastic, substantially inextensible yarn. Such threads are available 
commercially. The bulkable thread is stitched into the sheet under 
substantial tension so that the substantially inextensible wrapping yarn 
is straight and so that the bulkable thread will retract during the 
bulking step to as little as 20 percent of its original length after 
bulking. 
Any substantially inextensible thread can be used for stitching in the 
second direction. Inextensible threads of nylon or polyethylene 
terephthalate are preferred. The substantially inextensible thread adds 
strength to the fabric in a direction that is at an angle of at least 50 
degrees to the reinforcing direction of the bulkable thread stitching. The 
substantially inextensible thread is substantially inextensible while 
being stitched and its length is not be substantially increased after 
stitching. However, the substantially inextensible thread can be a 
bulkable thread which is substantially inextensible during the stitching 
but then retracts and becomes shorter and as a result is extensible after 
bulking. A preferred bulkable thread used in the capacity of a 
substantially inextensible thread is the aforementioned elastomeric yarn 
wrapped with inextensible yarn and stitched under tension sufficient to 
straighten the wrapping yarn. 
Usually the threads supplied by the two thread systems amount to no more 
than 20% of the weight of the stitchbonded fabric. For economy however, 
the weight of stitching thread often amounts to only 2 to 10% of the total 
fabric weight and sometimes as little as 3 to 5%. 
In a preferred embodiment of the invention, the first system of bulkable 
thread forms rows of chain stitches in and along the length of the fibrous 
layer. In another embodiment the bulkable thread forms a series of 
interlocked loops on one surface of the fibrous layer and a parallel 
series of zigzag tricot stitches on the other surface. Such rows of 
stitches are typical of those made by a "Mali" or an "Arachne" or "Liba" 
multi-needle stitching machine. With regard to area contraction or 
gathering caused by retraction of the bulkable stitching, chain stitches 
cause almost all gathering to be in the longitudinal direction of the 
stitched layer and tricot stitches cause gathering across the width as 
well as along the length of the fabric. 
In accordance with the invention, the second thread system provides 
multi-needle stitching and reinforcement in the second direction with 
substantially inextensible thread. The thread forms chain stitches, tricot 
stitches, inlay stitches or any other commonly used stitching, with the 
proviso that the angle between reinforcing directions of the bulkable and 
inextensible threads is at an angle of at least 50 degrees. 
In the manufacture of nonwoven fibrous layers used as starting materials 
for the stitchbonded fabrics of the invention, more strength is usually 
developed in the longitudinal (machine or "MD") direction than in the 
transverse (cross-machine or "XD") direction. For the stitchbonded fabrics 
of the present invention, it is advantageous to arrange the bulkable 
threads in the stronger or longitudinal direction and the substantially 
inextensible threads in the weaker or transverse direction. Reference 
herein to a first direction generally means the longitudinal direction 
("MD") and reference to a second direction generally means the transverse 
direction, although such is not required. 
The rows of stitches generally have a spacing in the range of 1 to 7 
stitches per cm, preferably 2 to 5. Chain stitching with bulkable thread 
is preferred in the first direction thread and "tricot" stitching with 1 
substantially inextensible thread is preferred in the second direction. 
With reference to the drawings attached hereto, note that FIG. 1 represents 
a stitchbonded fabric of the invention in which bulkable thread 10 is in 
the form of chain stitching in the strong direction of the starting 
nonwoven fibrous layer and inextensible thread 20 is in the form of 
1-0,3-4 "3-across tricot" stitching in the weak direction of the nonwoven 
fibrous layer. The angle between the reinforcing directions of the two 
thread systems is greater than 50 degrees. (The method of determining the 
angle is given hereinafter with regard to FIG. 3.) For the fabric 
represented in FIG. 1, the angle would be at least 72 degrees, if the 
stitch spacing and needle spacing were equal. 
Usually, the inextensible threads are stitched, laid in or arrayed in the 
transverse (i.e., the usually weaker) direction of the fibrous nonwoven 
layer. In some instances however, for example, when the fibrous layer is 
formed by crosslapping, the transverse direction may be the strong 
direction of the fabric. Under such circumstances, it is often preferable 
to use the bulkable thread in the transverse direction to apply tricot or 
other patterned stitches. 
Fabric characteristics and properties are measured by the following 
procedures. 
Unit weight of the starting fibrous layer and of the final stitchbonded 
fabric are measured in accordance with ASTM D 3776-79. The weight of 
thread per unit area of fabric is determined by removing and weighing the 
thread from a given area of fabric. 
Fabric weight is determined by weighing a known area of sheet which was cut 
while it was flattened between plates. 
Percent area gather of a fabric is determined measuring its dry area, 
before (A.sub.i) and after (A.sub.g) the fabric has been wetted thoroughly 
with water. Drying is performed at 250of for 10 minutes. The wetting and 
drying treatment causes the fabric to gather. Percent area gather, %G, is 
then calculated by the formula 
EQU %G=100 (A.sub.i -A.sub.g)/A.sub.i. 
Washability is determined by exposing a fabric sample to repeated washing 
and drying cycles in a home laundry automatic washer and tumble dryer and 
when applicable, recording the total number of cycles until failure (i.e., 
until the samples show tears, holes, or other signs of disintegration, or 
more than 5% weight loss). The washing and drying is conducted in 
accordance with AATCC Test Method 135-1978 for washing and tumble drying. 
"AATCC" is the American Association of Textile Chemists and Colorists. 
Grab strengths are measured at 70of and 65% relative humidity using an 
Instron tensile testing machine. Grab strength is determined in general 
accordance with ASTM Method D-1117-80, on a 4-inch (10.2 cm) wide by 
6-inch (15.2 cm) long sample. A gauge length of 3 inches (7.6 cm), clamps 
having 1-inch (2.5 cm) wide jaws, and an elongation rate of 12 inches 
(30.5 cm) per minute are used. The grab strength is reported in pounds 
force. For each reported measurement, ten determinations were made in the 
machine direction (MD) of the fabric and ten were made in the transverse 
direction (TD) (i.e., perpendicular to the MD). The average of the MD and 
the TD measurements are reported separately. Grab strengths were measured 
for wet (i.e., after being thoroughly soaked in water) and dry samples (a) 
as made, (b) after one washing and (c) after five washings. The washing 
and drying were conducted in the same equipment as was used for the 
washability test. 
The "hand split" test is a subjective evaluation of the handling strength 
of a fabric. The fabric to be tested is pressed on a smooth, flat surface 
with two thumbs touching and the thumbs are repeatedly drawn apart in an 
attempt to cause the fabric to split. If the fabric splits without 
stitching thread breakage, the fabric fails the test. If the fabric cannot 
be split without breaking the stitching thread, the fabric passes the 
test. 
The angle at which the direction spaced apart rows of stitches formed by 
the first thread system intersects the second direction of the spaced 
apart rows formed by the second thread system, can be determined by plane 
geometry from the stitch diagrams of the two thread systems. The angles 
can also be determined by simple geometry by examining the straight line 
segments of the threads between courses with the fabric held in an 
extended (but not deformed) condition. The direction of the spaced apart 
rows is the direction that the straight line portions of the threads 
travel in proceeding between successive courses. In warp knitting, these 
straight line segments are often referred to as the "floats" of the 
stitches. To illustrate the determination, FIG. 3 shows an intersection 
between vertical floats 10 of chain stitches falling along the 
longitudinal axis (MD) of a fabric of the invention and floats 20 of the 
second thread system of that fabric. The float and reinforcing directions 
coincide with each other. The angles formed between the two directions of 
floats are "a" and "b" and the angle that the floats make with the 
transverse direction (TD) is "c". The present invention requires that the 
angle between the directions the two thread systems be greater than 50 
degrees. Thus, the angle "a" and "b" each must be greater than 50.degree.. 
As shown in this illustration, the angles are calculated in degrees by the 
relationships: 
EQU a=90-c 90-14.5=75.5 
EQU b=90+c 90+14.5=104.5 
EQU c=tan.sup.-1 (L/nS) 
wherein 
L is the spacing between successive courses of stitches (or the reciprocal 
of the number of stitches per unit length in the fabric direction inserted 
by the machine), 
S is the spacing between rows of stitches is (equal to the needle spacing, 
or reciprocal of the gage of the multi-needle stitching machine), and 
n is the number of needle spaces traversed by the second thread system in 
proceeding between successive courses. 
EXAMPLES 
The following examples illustrate the preparation of multi-needle stitched 
nonwoven fabrics in accordance with the invention and compare them to 
similar multi-needle stitched nonwoven fabrics which are outside the 
invention. In the Examples, samples of the invention are designated with 
Arabic numerals; comparison samples have an upper case letter in their 
designations. 
Several types of fibrous starting layers are used to prepare the fabrics 
described in each example. The fibrous layers range from the weakest and 
least durable wood-pulp paper of Example 1 which falls apart when soaked 
in water, to the fairly strong and durable, but not washable and 
launderable, point-bonded web of a blend of staple fibers of Example 5. 
Further specific details of the fibrous layers are given in each example. 
In the examples, all the stitched samples and comparisons, bulkable threads 
were multi-needle stitched with a stitch frequency of 11.5 stitches per 
inch (4.5 per cm) in the first or longitudinal direction (also called 
"machine direction" or "MD"). In samples and comparisons that were also 
stitched in a second direction, substantially inextensible threads and a 
"gage" of 14 stitches per inch (5.5 per centimeter) were employed. The 
bulkable threads were stitched in a chain stitch and the substantially 
inextensible threads were "laid-in" stitches or "tricot" stitches with 
floats traversing one or two or four needle spaces. In the summary tables 
of the examples, the following designations were used to identify the 
particular thread systems and stitch patterns. 
Thread systems: 
I-0. An inextensible, 40-den (44-dtex), 34-filament flat nylon thread. 
Y-1. A bulkable, 40-den (44-dtex), 13 filament, textured nylon knitting 
yarn. 
Y-2. A bulkable, 20-den (22-dtex) spandex filament wrapped with 40-den 
(44-dtex) nylon. 
I-1. Same as Y-1, but in extended and substantially inextensible state when 
stitched. 
I-2 Same as V-2, but in extended and substantially inextensible state when 
stitched 
Stitch patterns: 
P. Pillar stitch (or chain stitch) 
T-1. Closed Tricot or 1 and 1 lap, 1-0,1-2 
T-2 Closed 2 and 1 lap, 1-0,2-3 
T-3. Closed 4 and 1 lap, 1-0,4-5 
L-1. "1-across" inlay (0-0,2-2) 
L-2. "2-across" inlay (0-0,3-3) 
L-3. "4-across" inlay (0-0,5-5) 
For each example, a summary table identifies for each sample of the 
invention and each comparison sample and reports stitching threads and 
stitch patterns that were used to construct the sample and the percent 
area gather and minimum angle (a or b of FIG. 2, whichever is smaller) 
between the reinforcing directions. Each table also reports the measured 
wet and dry grab strength, hand splittablity, and washability of each 
sample. 
EXAMPLE 1 
In this example, two nonwoven fabrics of the invention are made from a 
fibrous layer of pure pine wood paper pulp containing no binder resins and 
nominally weighing 1.2 oz/yd.sup.2 (40.7 g/m.sup.2). The samples of the 
invention (1-1 and 1-2) are stitchbonded with a two thread system, one of 
which supplies bulkable thread. The stitchbonded samples are compared to 
the fibrous layer without stitching (A-1) and with stitchbonding that is 
outside the invention (A-2, A-3). This example demonstrates the 
extraordinary strength that is added to ordinary paper (that usually falls 
apart when simply immersed in water) after it has been stitchbonded i 
accordance with the invention. Samples 1-1 and 1-2 of the invention are 
highly suited for use as wet or dry wipe-cloths. Table 1 below summarizes 
the preparation of the samples and their resultant properties 
A-1 through A-3 are comparison samples which lack adequate stitching to 
stabilize the fabric in accordance with the invention. The 1-across tricot 
stitching is made with an angle of 39.degree. between the threads of the 
two directions (i.e., angle alpha between the longitudinal direction of 
the row of chain stitches with their vertical floats and the float of the 
tricot stitches, as illustrated in FIG. 1). The 2-across stitching is made 
with an angle of 59o and the 4-across, with an angle of 73.degree.. 
Results of the testing are reported in Table 1. 
TABLE 1 
______________________________________ 
Example 1 
Sample 
A-1 A-2 A-3 1-1 1-2 
______________________________________ 
Fabric Weight, 
oz/yd.sup.2 1.39 1.73 2.12 2.06 2.04 
g/m.sup.2 47.1 58.6 71.9 69.8 69.2 
First Thread System 
None Y-1 Y-1 Y-1 Y-2 
Pattern -- P P P P 
Second Thread 
None None I-0 I-0 I-2 
System 
Pattern -- -- L-1 L-2 T-3 
Minimum Angle, 
-- -- 39 59 73 
degrees 
Grab Strength, 
as made 
Dry MD, lb force 
13.3 55.0 23.7 25.3 25.4 
Newtons 59 245 105 113 113 
Dry TD, lb force 
8.5 2.5 19.6 28.8 29.4 
Newtons 38 11 87 128 131 
Wet MD, lb force 
0.5 37.4 16.4 19.2 23.6 
Newtons 2.2 16.6 77 85 105 
Wet TD, lb force 
0 0 15.8 28.2 29.2 
Newtons 0 0 70 125 130 
Hand Split Test 
Wet FAIL FAIL FAIL PASS PASS 
Dry FAIL FAIL FAIL PASS PASS 
______________________________________ 
The superior strength exhibited by the samples stitchbonded according to 
the invention versus the comparison samples, is evident from the reported 
grab strengths and hand-splittability results. The comparison samples 
failed the splittability test; both fabrics of the invention passed. All 
samples failed the washability test. The short, loose fibers of the 
unbonded fibrous starting layer are believed to be the source of the 
failures. However, samples 1-1 and 1 of the invention still made very good 
reusable dry or wet wipes. 
EXAMPLE 2 
This example illustrates preparation of nonwoven fabric by multi-needle 
stitching a fibrous starting layer in the form of a reinforced paper of 
1.2 oz/yd.sup.2 (40.7 g/m.sup.2) made from a mixture of 75 weight % paper 
pulp and 25% 1.35-den (1.5-dtex), 0.5-inch (1.27-cm) long fibers of 
polyethylene terephthalate. The construction and measured properties of 
the samples are summarized in Table 2 below. In contrast to the strength 
and washability of the samples of the invention 2-1, 2-2 and 2-3, all 
comparison samples failed to survive more than five washing cycles tests 
and all failed the hand splittability test. Note that comparison sample 
B-1 had no stitchbonding threads and B-2 and B-3 each had only one yarn 
system. 
EXAMPLE 3. 
This example describes preparation of two stitchbonded samples of the 
invention (3-1 and 3-2) from a fibrous layer which is a 1.9 oz/yd.sup.2 
(64.4 g/m2), spunlaced, two-layer reinforced paper, one layer being of 
pine wood paper pulp and amounting to 60 % of the composite weight and the 
other layer being of 1.35-den (1.5-dtex), 7/8-inch (2.2-cm) long fibers of 
polyethylene terephthalate and amounting to 40% of the composite weight. 
Four comparison samples were also made with the same fibrous layer: C-1 
having no stitchbonding; C-2 and C-3 each having but one stitchbonding 
thread system; and C-4 having two thread systems, one bulkable and one 
inextensible, a minimum angle between the reinforcing directions of only 
39 degrees (versus at least 50 degrees according to the invention). Table 
3 summarizes the sample constructions and shows how very well the fabrics 
of the invention withstand repeated wash cycles, - more than 75 washes for 
samples of the invention versus fewer than 2 for comparison samples. 
TABLE 2 
______________________________________ 
Example 2 
Sample 
B-1 B-2 B-3 2-1 2-2 2-3 
______________________________________ 
Fabric Weight, 
oz/yd.sup.2 1.23 1.65 2.0 2.1 2.1 2.1 
g/m.sup.2 41.7 55.9 67.8 71.2 71.2 71.2 
First Thread none Y-1 none Y-1 Y-1 Y-1 
Pattern -- P -- P P P 
Second Thread 
none none I-1 I-0 I-0 I-2 
Pattern -- -- T-1 T-2 L-3 T-3 
Minimum angle 
-- -- -- 59 73 73 
% Area Gather 
SD* 9 11 13 17 65 
Grab Strengths 
As made 
Dry MD, lbs 6.3 23.2 25.1 30.6 25.1 25.1 
Newtons 28 103 112 136 112 112 
Dry TD, lb 5.4 1.6 3.2 20.4 33.8 24.0 
N 24 7 14 91 150 107 
Wet MD, lb 3.3 18.1 22.1 29.5 24.4 21.8 
N 15 81 98 131 109 97 
Wet TD, lb 3.2 1.1 2.6 20.8 28.6 32.5 
N 14 5 12 93 127 127 
After 1 wash 
Dry MD, lb 5.0 18.3 23.5 35.7 22.3 24.3 
N 22 81 105 159 99 109 
Dry TD, lb 3.2 2.5 11.1 35.8 29.8 43.5 
N 14 11 49 159 133 194 
Wet MD, lb 3.5 16.6 19.9 35.8 20.4 20.2 
N 16 74 89 159 91 90 
Wet TD, lb 2.4 1.4 4.4 26.9 28.5 32.5 
N 11 6 20 120 127 145 
After 5 washes 
Dry MD, lb FW* FW 23.0 37.8 18.1 23.2 
N FW FW 102 168 81 103 
Dry TD, lb FW FW 5.8 36.2 39.3 39.8 
N FW FW 26 161 175 177 
Wet MD, lb FW FW 16.6 37.4 15.0 24.1 
N FW FW 74 166 67 107 
Wet TD, lb FW FW 7.6 28.3 22.6 37.3 
N FW FW 34 126 101 166 
Hand Split Test 
Wet Fail Fail Fail Pass Pass Pass 
Dry Fail Fail Fail Pass Pass Pass 
Number of Washes 
1 1-2 5 55 75+ 75+ 
until failure 
______________________________________ 
*Notes: 
SD = Sample deteriorated in water. 
FW = Failed wash test. 
TABLE 3 
______________________________________ 
Example 3 
Sample 
C-1 C-2 C-3 C-4 3-1 3-2 
______________________________________ 
Fabric Weight, 
oz/yd.sup.2 1.9 2.2 2.3 2.6 2.4 2.4 
g/m.sup.2 64 76 78 88 81 81 
First Thread none Y-1 none Y-1 Y-1 Y-2 
Pattern -- P -- P P P 
Second Thread 
none none I-1 I-0 I-0 I-2 
Pattern -- -- T-1 L-1 T-2 T-3 
Minimum angle 
-- -- -- 39 59 73 
% Area Gather 
-- 20 17 12 19 69 
Grab Strengths 
As made 
Dry MD, lbs 37.2 39.9 39.4 70.5 43.0 34.9 
Newtons 166 177 175 314 191 155 
Dry TD, lb 20.1 7.3 10.2 8.4 41.0 39.0 
N 89 32 45 37 182 174 
Wet MD, lb 32.1 32.7 32.3 75.9 34.8 30.0 
N 143 146 144 338 155 134 
Wet TD, lb 16.2 6.5 9.8 11.3 33.0 33.8 
N 72 29 44 50 147 150 
After 1 wash 
Dry MD, lb FW FW 33.2 FW 35.6 38.2 
N FW FW 148 FW 158 176 
Dry TD, lb FW FW 6.5 FW 41.7 33.5 
N FW FW 29 FW 186 149 
Wet MD, lb FW FW 22.7 FW 32.3 45.4 
N FW FW 101 FW 144 202 
Wet TD, lb FW FW 5.4 FW 34.9 28.1 
N FW FW 24 FW 155 125 
After 5 washes 
Dry MD, lb FW FW FW FW 37.6 43.1 
N FW FW FW FW 167 192 
Dry TD, lb FW FW FW FW 41.0 33.9 
N FW FW FW FW 182 151 
Wet MD, lb FW FW FW FW 28.9 58.3 
N FW FW FW FW 129 259 
Wet TD, lb FW FW FW FW 35.7 28.1 
N FW FW FW FW 159 125 
Hand Split Test 
Wet Fail Fail Fail Pass Pass Pass 
Dry Fail Fail Fail Pass Pass Pass 
Number of Washes 
0 0 2 1 75+ 75+ 
until failure 
______________________________________ 
Notes: 
-- = not measured or inapplicable. 
See Table 2 for other notes. 
EXAMPLE 4 
In this example two stitohbonded samples of the invention (4-1 and 4-2) are 
prepared with two yarn systems and a 1.2-oz/yd.sup.2 (40.7-g/m2) lightly 
spunlaced web of 7/8-inch (2.2-cm) long, 1.35-den (1.5-dtex)fibers of 
polyethylene terephthalate. Three comparison samples are also prepared 
with the same fibrous layer: D-1 which has no stitching; samples D-2 which 
is stitched with only one yarn system; and D-3 which is stitched with two 
thread systems that do not provide the minimum angle between the 
reinforcing directions of the stitching. Table 4, below, which summarizes 
the sample constructions and measured characteristics, again demonstrates 
the advantages in strength and repeated washability of the stitchbonded 
fabrics of the invention over comparison samples. 
EXAMPLE 5 
This example illustrates the advantages of the invention with stitchbonded 
fibrous layer which is point-bonded carded web. The web is formed from a 
blend of 75 weight percent of 1.5-inch (3.8-cm) long, 1.5-den (1.7-dtex) 
acrylic fibers and 25 % of 3-inch (7.6-cm) long, 3-den (3.3-dtex) 
polyester fibers of lower melting temperature than the acrylic fibers. The 
web was point bonded at 100 psi (689 kPa) and 160.degree. C. with a 
regular pattern of 625 points per in2 (96.9/cm2), each point having a 
diameter of 0.020 inch (0.05 mm). Two such samples of the invention, 5-1 
and 5-2, are compared with three comparison samples. The comparisons are: 
E-1, the point-bonded web without stitching; and E-2 and E-3, which are 
each stitched with only one thread system. Table 5, below, summarizes the 
construction and properties of the samples and again shows the clear 
advantages in strength, resistance to splitting and repeated washability 
of the fabrics of the invention over the comparison samples. 
TABLE 4 
______________________________________ 
Example 4 
Sample 
D-1 D-2 D-3 4-1 4-2 
______________________________________ 
Fabric Weight, 
oz/yd.sup.2 1.16 1.43 1.64 1.57 1.53 
g/m.sup.2 39.3 48.5 55.6 53.2 51.9 
First Thread none Y-1 Y-1 Y-1 Y-2 
Pattern -- P P P P 
Second Thread 
none none I-0 I-0 I-2 
Pattern -- -- T-1 L-2 T-3 
Minimum angle 
-- -- 39 59 73 
% Area Gather 
-- 14 21 22 72 
Grab Strengths 
As made 
Dry MD, lbs 24.6 29.5 25.3 28.4 64.8 
Newtons 109 131 113 126 288 
Dry TD, lb 11.3 4.0 12.9 14.2 22.4 
N 50 18 57 63 100 
Wet MD, lb 18.6 29.6 29.3 23.3 56.8 
N 83 132 130 104 253 
Wet TD, lb 10.5 6.9 11.6 14.4 22.6 
N 47 31 52 64 101 
After 1 wash 
Dry MD, lb 20.5 22.9 FW 18.4 64.5 
N 91 102 FW 82 287 
Dry TD, lb 10.8 9.4 FW 12.6 38.2 
N 48 42 FW 56 170 
Wet MD, lb 18.6 21.7 FW 18.0 61.9 
N 83 97 FW 80 275 
Wet TD, lb 9.3 8.5 FW 12.0 33.5 
N 41 38 FW 53 144 
After 5 washes 
Dry MD, lb 18.2 FW FW 19.3 68.3 
N 81 FW FW 86 304 
Dry TD, lb 11.0 FW FW 15.3 38.0 
N 49 FW FW 68 169 
Wet MD, lb 19.5 FW FW 19.9 62.0 
N 87 FW FW 89 276 
Wet TD, lb 9.2 FW FW 13.8 33.5 
N 41 FW FW 61 149 
Hand Split Test 
Wet Fail Fail Fail Pass Pass 
Dry Fail Fail Fail Pass Pass 
Pass 
Number of Washes 
5 2 2 75+ 75+ 
until failure 
______________________________________ 
Notes: 
Same as in Table 3. 
TABLE 5 
______________________________________ 
Example 5 
Sample 
E-1 E-2 E-3 5-1 5-2 
______________________________________ 
Fabric Weight, 
oz/yd.sup.2 2.1 2.4 2.5 2.7 2.6 
g/m.sup.2 71.2 81.4 84.8 91.5 88.1 
First Thread none Y-1 none Y-1 Y-2 
Pattern -- P -- P P 
Second Thread 
none none I-0 I-0 I-2 
Pattern -- -- T-1 L-3 T-3 
Minimum angle 
-- -- -- 73 73 
% Area Gather 
-- 14 10 18 64 
Grab Strengths 
As made 
Dry MD, lbs 13.6 20.0 10.0 34.0 36.6 
Newtons 61 89 89 151 163 
Dry TD, lb 1.0 9.5 6.6 30.8 25.7 
N 4.5 42 29 137 114 
Wet MD, lb 12.8 19.1 15.1 29.1 32.8 
N 57 85 67 137 114 
Wet TD, lb 1.3 8.5 5.5 27.6 17.9 
N 5.9 38 24 123 146 
After 1 wash 
Dry MD, lb FW FW 15.4 33.4 43.2 
N FW FW 69 149 192 
Dry TD, lb FW FW 9.1 35.7 37.3 
N FW FW 40 159 166 
Wet MD, lb FW FW 14.7 26.3 45.1 
N FW FW 65 117 201 
Wet TD, lb FW FW 9.2 30.6 35.4 
N FW FW 41 136 158 
After 5 washes 
Dry MD, lb FW FW FW 33.0 45.2 
N FW FW FW 147 201 
Dry TD, lb FW FW FW 37.0 37.1 
N FW FW FW 165 165 
Wet MD, lb FW FW FW 31.3 43.1 
N FW FW FW 139 192 
Wet TD, lb FW FW FW 26.3 38.2 
N FW FW FW 117 170 
Hand Split Test 
Wet fail fail fail pass pass 
Dry fail fail fail pass pass 
Number of Washes 
0 0 2 60 75+ 
until failure 
______________________________________ 
Notes: 
Same as in Table 3.