The present invention relates generally to methods of making
nonwoven fabrics, and more particularly to a method of manufacturing three-dimensional
imaged nonwoven fabrics exhibiting flame-retardant characteristics while retaining
aesthetic appeal, abrasion resistance, and fabric strength, these properties permitting
use of the fabric in wall cover applications.
Background of the Invention
Significant quantities of textile fabric are employed in
the construction of domestic and business furnishings, room dividers and acoustic
panels. Manufactures of such textile fabrics are cognizant of the end-use of their
materials in these constructions and have looked to improve the aesthetic qualities
of the fabrics. Further, manufactures have also taken safety into consideration
and looked to ways in which the textile fabric can be imparted with improved levels
of flame retardancy.
The production of conventional textile fabrics is known
to be a complex, multi-step process. The production of fabrics from staple fibers
begins with the carding process where the fibers are opened and aligned into a feedstock
known as sliver. Several strands of sliver are then drawn multiple times on drawing
frames to further align the fibers, blend, improve uniformity as well as reduce
the diameter of the sliver. The drawn sliver is then fed into a roving frame to
produce roving by further reducing its diameter as well as imparting a slight false
twist. The roving is then fed into the spinning frame where it is spun into yam.
The yarns are next placed onto a winder where they are transferred into larger packages.
The yarn is then ready to be used to create a fabric.
For a woven fabric, the yarns are designated for specific
use as warp or fill yarns. The fill yarn packages (which run in the cross direction
and are known as picks) are taken straight to the loom for weaving. The warp yarns
(which run on in the machine direction and are known as ends) must be further processed.
The packages of warp yarns are used to build a warp beam. Here the packages are
placed onto a warper, which feeds multiple yarn ends onto the beam in a parallel
array. The warp beam yarns are then run through a slasher where a water-soluble
sizing is applied to the yarns to stiffen them and improve abrasion resistance during
the remainder of the weaving process. The yarns are wound onto a loom beam as they
exit the slasher, which is then mounted onto the back of the loom. Here the warp
and fill yarns are interwoven in a complex process to produce yardages of textile
In contrast, the production of nonwoven fabrics from staple
fibers is known to be more efficient than traditional textile processes as the fabrics
are produced directly from the carding process with a topical treatment of the nonwoven
fabric readily being applied.
Nonwoven fabrics are suitable for use in a wide-variety
of applications where the efficiency with which the fabrics can be manufactured
provides a significant economic advantage for these fabrics versus traditional textiles.
However, nonwoven fabrics have commonly been disadvantaged when fabric properties
are compared, particularly in terms of surface abrasion, pilling and durability
in multiple-use applications. Hydroentangled fabrics have been developed with improved
properties, which are a result of the entanglement of the fibers or filaments in
the fabric providing improved fabric integrity. Subsequent to entanglement, fabric
durability can be further enhanced by the application of binder compositions and/or
by thermal stabilization of the entangled fibrous matrix. However, the use of such
means to obtain fabric durability comes at the cost of a stiffer and less appealing
The resulting textile or nonwoven fabric requires further
processing before a suitable material is available for the construction of furnishings.
Fabric constructed by either mechanism is essentially planar, having little in way
of macroscopic asperities, let alone, a three-dimensional aesthetic quality. It
has been necessary in the art to further treat the fabric with embossing techniques
or complex foaming agents in order to impart the fabric with a multi-planar, aesthetic
quality. In addition, depending upon whether or not the textile fabric was woven
from costly flame-retardant staple fiber, a subsequent topical treatment containing
an appropriate flame-retardant chemistry is required.
U.S. Patent No. 3,485,706, to Evans discloses processes
for effecting hydroentanglement of nonwoven fabrics. More recently, hydroentanglement
techniques have been developed which impart images or patterns to the entangled
fabric by effecting hydroentanglement on three-dimensional image transfer devices.
Such three-dimensional image transfer devices are disclosed in U.S. Patent No. 5,098,764
with the use of such image transfer devices being desirable for providing a fabric
with enhanced physical properties as well as an aesthetically pleasing appearance.
In preparing an imaged nonwoven material by the present
invention for use in furnishings, the material has also been found to have inherent
physical properties that render the material eminently suitable for wall coverings,
window coverings, upholstery, and drapery applications, which are hereby referenced
as co-pending applications.
Heretofore, attempts have been made to develop flame-retardant
nonwoven fabrics exhibiting the necessary aesthetic and physical properties for
durable consumer applications.
U.S. Patent No. 4,320,163, to Schwartz discloses a three-dimensional
ceiling board facing. This patent contemplates selectively coating a flame-retardant
substrate with a print paste consisting of a foamable plastisol. By then exposing
said-coated substrate to an elevated temperature, the plastisol increases variably
in height under the influence of expanding thermoplastic microspheres, forming a
roughened or "pebbled" surface.
A construct is disclosed in U.S. Patent No. 4,830,897,
to Seward, whereby an initial woven textile fabrics receives thereupon a heat dissipating
metallic foil followed by a fibrous batt. The application of a subsequent mechanical
needling procedure integrates the layers into a unitary construct.
US patent No. 5,437,904 to Roger Boulanger et al. discloses
a method for entangling loosely associated fibres to form a unitary reticular network
by using fluid streams applied in opposition to the fibres. This patent employs
fibers such as Nomex for fabric construct.
US patent No. 5,252,386 to J. Hughes and Van Oglesby discloses
an entangled nonwoven fabric of polyester fibers, which has balanced tensile strength
properties and improved fire retardant properties. The balanced tensile strength
properties and improved fire retardant properties are achieved by cross stretching
the entangled fabric after the fabric has been wetted with an aqueous-based fire
retardant composition and drying the wetted fabric while maintaining it in its stretched
US patent No. 3,485,706 to James Evans et al. discloses
textile-like nonwoven fabrics of fibers randomly entangled with each other in a
repeating pattern of localized entangled regions interconnected by fibers extending
between adjacent entangled regions. It also discloses a process for consolidating
fibers or filaments into strong patterned structures without using the conventional
process steps previously required for producing strong, nonbonded, patterned fabrics,
such as weaving, knitting, netting or the like, and without the need for binder
or other supplementary treatment.
There are a number of Japanese patents directed to nonwoven
fabrics used as a component in wall covering fabrication. JP10168756 to Kawano,
et al., utilizes a flame-retardant spunbond containing diguanidine phosphate laminated
to a wallpaper backing. A wallpaper is disclosed in JP10131097 to Takeuchi, et al.,
whereby a nonowoven fabric is adhesively bonded to wallpaper backing, the adhesive
containing a significant amount of a high specific gravity fireproofing agent. JP3251452
to Nakakawara, et al., discloses an alternate foam texturing process wherein a uniform
foam layer is initially applied to a nonwoven substrate, then a solvent is printed
thereon to reductively pattern the laminate. A final patent of interest is JP11335958
to Nanbae, et al., whereby a two layered nonwoven fabric, each layer consisting
of less than 20% thermally fusible fibers is subjected to an embossing process.
As can be seen in the prior art, there has not been an
effective melding of three-dimensional aesthetic qualities with flame-retardant
properties in a fabric suitable for furnishing, window covering, and wall covering
Summary of the Invention
In accordance with the present invention, a method of making
a flame-retardant nonwoven fabric is defined in independent claim 1 and a flame-retardant
nonwoven fabric is defined in independent claim 5. Advantageous embodiments are
claimed in dependent claims.
Other features and advantages of the present invention
will become readily apparent from the following detailed description, the accompanying
drawings, and the appended claims.
Brief Description of the Drawings
The invention will be more easily understood by a detailed
explanation of the invention including drawings. Accordingly, drawings, which are
particularly suited for explaining the invention, are attached herewith; however,
it should be understood that such drawings are for explanation purposes only and
are not necessarily to scale. The drawings are briefly described as follows:
- FIGURE 1 is a diagrammatic view of an apparatus for manufacturing a durable
nonwoven fabric, embodying the principles of the present invention:
- FIGURE 2 is a diagrammatic view of an apparatus for the application of a flame-retardant
finish onto a nonwoven fabric, embodying the principles of the present invention;
- FIGURE 3 is a fragmentary top plan view of a three-dimensional image transfer
device of the type used for practicing the present invention, referred to as "slubs";
- FIGURE 4 is a fragmentary top plan view of a three-dimensional image transfer
device of the type used for practicing the present invention, referred to as "cross
- FIGURE 5 is a photograph of the resultant material utilizing the image transfer
device depicted in FIGURE 3; and
- FIGURE 6 is a photograph of the resultant material utilizing the image transfer
device depicted in FIGURE 5.
While the present invention is susceptible of embodiment
in various forms, there is shown in the drawings and will hereinafter be described
a presently preferred embodiment of the invention, with the understanding that the
present disclosure is to be considered as an exemplification of the invention, and
is not intended to limit the invention to the specific embodiment illustrated.
In accordance with the present invention, a durable flame-retardant
nonwoven fabric can be produced which can be employed in a wide variety of wall
coverings described as applied to wallpaper. It should be understood, however, that
upon suitable modification the invention can be adapted for use with cloth, wood
veneer, plastic or combinations thereof, as exemplified by U.S. Patent No. 3,663,269
to Fischer et al. with the fabric exhibiting sufficient flame-retardancy, drapeability,
abrasion resistance, strength, and tear resistance, with colorfastness to light.
It has been difficult to develop nonwoven fabrics that achieve the desired hand,
drape, and pill resistance that are inherent in woven fabrics.
In the case where nonwoven fabrics are produced using staple
length fibers, the fabric typically has a degree of exposed surface fibers that
will abrade or "pill" if not sufficiently entangled, and/or not treated with the
appropriate polymer chemistries subsequent to hydroentanglement. The present invention
provides a finished fabric that can be conveniently cut, sewn, and packaged for
retail sale or utilized as a component in the fabrication of a more complex article.
The cost associated with designing/weaving, fabric preparation, dyeing and finishing
steps can be desirably reduced.
With reference to FIGURE 1, therein is illustrated an apparatus
for practicing the present method for forming a nonwoven fabric. The fabric is formed
from a fibrous matrix preferably comprising staple length fibers, but it is within
the purview of the present invention that different types of fibers, or fiber blends,
can be employed. The fibrous matrix is preferably carded and cross-lapped to form
a precursor web, designated P. In current embodiments, the precursor web comprises
staple length polyester fibers, particularly polyester having an independent level
FIGURE 1 illustrates a hydroentangling apparatus for forming
nonwoven fabrics in accordance with the present invention. The apparatus includes
a foraminous forming surface in the form of belt 12 upon which the precursor web
P is positioned for pre-entangling by entangling manifold 14.
The entangling apparatus of FIGURE 1 further includes an
imaging and patterning drum 18 comprising a three-dimensional image transfer device
for effecting imaging and patterning of the lightly entangled precursor web. The
image transfer device includes a moveable imaging surface which moves relative to
a plurality of entangling manifolds 22 which act in cooperation with three-dimensional
elements defined by the imaging surface of the image transfer device to effect imaging
and patterning of the fabric being formed.
Manufacture of a durable nonwoven fabric embodying the
principles of the present invention is initiated by providing the precursor nonwoven
web, preferably in the form of a 100% flame-retardant polyester or polyester blend.
The use of the polyester desirably provides drape, which upon treatment with the
specific binder formulation listed herein, results in a material with improved flame
retardant properties at relatively low cost. During invention development, fibrous
layers comprising flame-retardant polyester, standard polyester, p-aramid, n-aramid,
melamine, and modacrylic fibers in blend ratios between about 100% by weight to
20% by weight minor component to 80% by weight major component were found effective.
Such blending of the layers in the precursor web was also found to yield aesthetically
pleasing color variations due to the differential absorption of dyes during the
optional dyeing steps.
After formation and integration of the imaged and patterned
nonwoven fabric, a flame-retardant binder finish is applied. The flame-retardant
binder finish includes chemistries to render the treated fabric the ability to resist
advanced thermal degradation and flame progression when exposed to combustion temperatures.
A preferred chemistry employed herein is based on a halogenated derivative of a
polyurethane backbone. Additional chemistries, including metallic salt extinguisants,
can be used in conjunction with the halogenated polyurethane.
Upon application and curing of the flame-retardant binder
finish on the imaged nonwoven fabric, the resulting fabric can be dyed by conventional
textile dying methods. Various dyeing methods commonly known in the art are applicable
including nip, pad, and jet, with the use of a jet apparatus and disperse dyes,
as represented by U.S. Patents No. 5,440,771 and No. 3,966,406 being most preferred.
Using a forming apparatus as illustrated in FIGURE 1, a
nonwoven fabric was made in accordance with the present invention by providing a
carded, randomized precursor fibrous batt comprising Type DPL 535 flame-retardant
polyester fiber, 1.5 denier by 3.81 cm (1.5 inch) staple length, as obtained from
Fiber Innovation Technology of North Carolina. The web had a basis weight of 9.48
mg/cm2 (2.8 ounces per square yard) (plus or minus 7%).
Prior to patterning and imaging of the precursor web, the
web was entangled by a series of entangling manifolds such as diagrammatically illustrated
in FIGURE 1. FIGURE 1 illustrates disposition of precursor web P on a foraminous
forming surface in the form of belt 12, with the web acted upon by entangling manifolds
14. In the present examples, each of the entangling manifolds included three each
120 micron orifices spaced at 42.3 per 2.54 cm (inch), with the manifolds successively
operated at 3 strips each at 7.04, 21.13 and 56.34 Bar (100, 300, 800 psi), at a
line speed of 18.29 m/min (60 feet per minute).
The entangling apparatus of FIGURE 1 further includes an
imaging and patterning drum 18 comprising a three-dimensional image transfer device
for effecting imaging and patterning of the now-entangled precursor web. The entangling
apparatus includes a plurality of entangling manifolds 22 that act in cooperation
with the three-dimensional image transfer device of drum 18 to effect patterning
of the fabric. In the present example, the three entangling manifolds 22 were operated
at 197.18 Bar (2800 psi), at a line speed which was the same as that used during
The three-dimensional image transfer device of drum 24
was configured as a so-called cross-slubs, as illustrated in FIGURE 4.
Subsequent to patterned hydroentanglement, the fabric was
dried on three consecutive steam cans at about 135°C (275°F), then received
a substantially uniform application by dip and nip saturation of a flame-retardant
binder composition at application station. The web was then directed through three
consecutive steam cans 41, operated at about 121.11°C (250°F)
In the present example, the pre-dye finish composition
was applied at a line speed of 18.29 m/min (60 feet per minute), with a nip pressure
of 2.25 Bar (32 pounds per square inch)and percent wet pick up of approximately
The flame retardant finish formulation, by weight percent
of bath, was as follows:
As is registered to and can be obtained from B.F. Goodrich of Akron, Ohio
- Water 90%
- Vycar 460x46 [vinyl chloride acrylic co-polymer binder] 10%
A fabric as made in the manner described in EXAMPLE 1,
whereby in the alternative the flame-retardant binder composition formulation, by
weight percent of bath, was as follows:
The above being registered to and can be obtained from
Chemonic Industries, of North Carolina.
As is registered to and can be obtained from B.F. Goodrich,
A fabric as made in the manner described in EXAMPLE 1,
whereby in the alternative 20.0% Pyron 6139 was used in place of 16% Pyron 6135
and 78.0% water was used in place of 82.0% water.
The following benchmarks have been established in connection
with nonwoven fabrics, which exhibit the desired combination of durability, softness,
abrasion resistance, etc., for certain home use applications.
Vertical Flame Test
Absorbency -- Capacity
Stiffness -- Cantilever
Colorfastness To Crocking
The test data in the attached tables shows that nonwoven
fabrics approaching, meeting, or exceeding the various above-described benchmarks
for fabric performance in general, and to commercially available products in specific,
can be achieved with fabrics formed in accordance with the present invention. For
many applications, fabrics having basis weights between about 6.76 mg/cm2
(2.0 ounces per square yard) and 20.32 mg/cm2 (6.0 ounces per square
yard) are preferred, with fabrics having basis weights of about 8.47 mg/cm2
(2.5 ounces per square yard) to about 11.85 mg/cm2 (3.5 ounces per square
yard) being most preferred. Fabrics formed in accordance with the present invention
are flame-retardant, durable and drapeable and are suitable for decorative wall
For upholstery and drapery applications, fabrics having
basis weights between about 6.76 mg/cm2 (2.0 ounces per square yard)
and 33.87 mg/cm2 (10.0 ounces per square yard) are preferred, with fabrics
having basis weights of about 10.16 mg/cm2 (3.0 ounces per square yard)
to about 20.32 mg/cm2 (6.0 ounces per square yard) being most preferred.
Fabrics formed in accordance with the present invention are flame-retardant, durable
and drapeable, and are not only suitable for covering or upholstering furniture
such as chairs, couches, love seats, and the like, but also draperies or hanging
fabric that prevents the admittance of any ambient light through the fabric.
For window covering applications, fabrics having basis
weights between about 1.69 mg/cm2 (0.5 ounces per square yard) and 20.32
mg/cm2 (6.0 ounces per square yard) are preferred, with fabrics having
basis weights of about 3.39 mg/cm2 (1.0 ounces per square yard) to about
13.55 mg/cm2 (4.0 ounces per square yard) being most preferred. Fabrics
formed in accordance with the present invention are flame-retardant, durable and
drapeable, and are suitable for window covering applications. Window coverings of
the present invention are those coverings that allow for the admittance of ambient
light through the fabric, such as sheets, shades, or blinds including, but not limited
to cellular, vertical, roman, soft vertical, and soft horizontal.
It is to be understood that no limitation with respect
to the specific embodiments illustrated herein is intended or should be inferred.
The disclosure is intended to cover, by the appended claims, all such modifications
as fall within the scope of the claims.