Note: Descriptions are shown in the official language in which they were submitted.
'~O 92/20524 PCT/L~S92/04363
FI~~C~D FABRIC PRINTING
Backcxround of the Tnvention
The present invention relates to improvements in
printing fabrics such as flocked fabrics or velvets,
although it is also applicable to other types of fabrics.
Velvets and flocked fabrics have a substrate with the
fibers standing up from the substrate, which give the
fabric a soft, luxurious, fluffy feel. These fibers also,
however, cause problems when it comes to printing tlae
fabric with a decorative pattern or other pattern. That
is, since the top surface of the fabric has vertically
extending fibers, it is difficult to thoroughly pr~.nt the
fabric without having grin through of the substrate and
other undesirable attributes.
This has typically been alleviated by using a very
high wet pick-up of dyes and print materials on the fabric
in order to achieve thorough saturation of the fabric with
the dyes and other print materials to be used. In a print,
however, it is important to obtain registration between th~
various colors to be printed in the pattern, an,d this is
made more diff~.cult by the presence of the nap on the
fabr~.c. Where one color should end and the other begin
cannot be as precisely defined on a napped fabric as a flat
fabric .
As a result, it has become commonplace in prznti.ng
fabrics of this type to use blotches as one of the colors
of the print. 1~3 blotch will tend to be a predominant color
in the print, constituting a background for the most part.
Blotches can be either fitted or full, and the desirability
of one or the other depends upon the nature of the pattern
to be printed. Where the other colors of the pattern tend
to be contiguous so that they are working together forming
a contiguous print, a fitted blotch which covers all the
other areas of the fabric is suitable. Where the pattern
is more dispersed, a full blotch is used in which the
printed and unprinted areas are overprinted by the blotch
in order to obtain thorough coverage. In a full blotch, a
SU~~'T!°fU'~'~ ~I-1C"
CA 02103451 2001-09-06
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resist is added to the print paste for the print pattern in
order to prevent the blotch from fixing in the areas of the
pattern. Then, when the fabric is washed following fixing,
the excess dye from the blotch will be washed away.
However, some of the dye from the blotch will,
inevitably, fix in the areas of the print, darkening the
print and giving it a muted or muddy look. As such, prints
on napped fabrics of this sort tend to be dark and the
colors not particularly distinctly defined, due to some
presence of the blotch.
It is known to apply a solid color dye to fabrics of
this sort followed by application of a print pattern with
a print paste having a discharge agent which takes away the
"blotch" color and replaces it with the desired color in
the area of the print. This in known as discharge
printing, but still achieves only relatively muted shades.
It is known in some circumstances to also apply a gold
overlay while applying the discharge print paste, but such
gold overlay constitutes a thin, not strongly adherent top
layer of gold to the tips of the fibers. The gold is,
accordingly, not very wear-resistant. Furthermore, the
cost involved in the two-step discharge printing is
considerable.
Accordingly, there is a need in the art for a napped
fabric having improved color brightness and distinctness in
its print, and an improved process for manufacturing such
fabric on a cost-effective basis.
Summary of the invention
The present invention fulfills this need in the
art by providing a fabric having colors with long wearing
capabilities comprising a textile substrate, raised fibers
on said substrate, an opaque particulate colorant adhering
to said raised fibers and arrayed on said fabric to form
portions of a printed pattern, a dye other than said opaque
particulate colorant arrayed on said fabric in other
CA 02103451 2001-09-06
3
portions of said printed pattern, and a melamine-latex
binder composition which adheres said opaque particulate
material to said fibers, and in which melamine and latex
are cross-linked, and a resist to cause said other dye not
to dye the fibers in the area of said melamine-latex binder
composition.
The fabric may be a flocked fabric, in which the
raised fibers adhere to the substrate. Alternatively, the
fabric can be a velvet fabric, in which the raised fibers
extend from yarns in the substrate. Other napped and flat
fabrics may also be used.
Examples of suitable opaque particulate colorants are
gold, bronze, pearlescent metals and titanium dioxide. The
colorant adheres to the fibers strongly enough to show only
very little wear after 15,000 cycles on a Wyzenbeek
abrasion test.
In a particularly preferred embodiment, the aye
is provided in a blotch, either fitted of full, which
assures full coloration of the fabric. The resist, however,
minimizes the fixing of the dye from blotch in the areas of
colorant. When the colorant is white, such as titanium
dioxide, the whiteness counteracts color from the blotch
which may fix, brightening the print.
In a particularly preferred embodiment, the fibers are
disperse-dyeable, and a disperse dye is included in the
opaque particulate colorant to dye fibers contacted by the
opaque particulate colorant. This can be used with a
blotch to good effect. When disperse dyes are used in the
colorant with a blotch, the white particulate colorant
lightens the fibers to counteract darkening caused by the
blotch, so the color from the disperse dye is more
apparent.
CA 02103451 2001-09-06
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The invention also provides a process of printing
a fabric having a textile substrate and raised fibers on
said substrate to achieve a long wearing coloration of the
fabric, the process comprising
making up a print paste of an opaque particulate
colorant and a latex-melamine binder composition including
mixing the colorant, a latex solution, a melamine solution,
a catalyst for the latex-melamine binder composition, and a
resist which inhibits fixing of dyes which dye differently
form the print paste from dyeing the fabric contacted by
the print paste,
applying the print paste to the fabric to form
potions of a printed pattern in a wet-on-wet printing
process which also includes applying dyes which dye
differently than the print paste in the form of a blotch
which covers at least some of the colorant,
performing a fixing process on the dye which dyes
differently than the print paste, and
curing the latex-melamine binder system to adhere
the opaque particulate colorant to the fabric.
Preferably, the making up step includes mixing a
melamine solution, and thickeners in proportions to achieve
a viscosity of at least about 15,000 centipoise.
Typically, the curing step includes exposing the
fabric to a temperature of at least about 300 degrees
Fahrenheit for at least about three minutes, although the
curing is desirably correlated with the catalyst added.
Preferably, the fixing step may take place
between the applying and curing steps, or may follow
curing.
CA 02103451 2001-09-06
4a
Preferably the other dyes are acid dyes, but
other dyeing systems may be used.
In one embodiment the making up step includes adding
a dye to the print paste. When the fibers are disperse-
dyeable, the dye is preferably a disperse dye. The
disperse dye is, of course, not affected by a resist added
to the print paste which is effective to resist dyeing of
the fibers with the acid dye.
Brief Description of the Drawings
1o Figures l and 2 are photographs of prior art fabrics.
Figures 3-6 are photographs of fabric printed in
accordance with the invention.
CA 02103451 2001-09-06
Detailed Description of the Preferred Embodiments
The improved process and product of the subject
invention are made possible by an improved print paste
5 formulation which can strongly adhere opaque particulate
colorant materials to the fibers of the fabric. The
preferred formulation operates on the basis of a melamine-
latex binder system, somewhat along the lines of other
melamine binder systems used in the art in textile
printing. However, the present formulation has been found
to provide particularly strong wear-resistant properties
for the particulate colorant on the flocked fabric.
A preferred melamine is the Cyres 963 melamine resin
solution available from American Cyanamid Co. of Bound
Brook, NJ. A preferred acrylic latex solution is Hycar
26419 available from H.F.Goodrich Co. of Avon Lake, Ohio.
These are generally blended in an aqueous solution with a
carboxylated thickener-solution, preferably 957 Paste
available from Polymer Industries, Div. of Morton-Thiokol
of Greenville, SC. This three-component system is further
combined with a catalyst for the latex melamine cross-
linking necessary for the binder system, and a preferred
catalyst is paratoluene sulfonic acid (PTSA), along with a
resisting agent which is Thiotan TR, available from Sandoz
Chemicals Corp. of Charlotte, NC. These components can be
blended together with a white RA paste of titanium dioxide
available from Mobay Co. of Rock Hill, SC, which serves as
the opaque particulate colorant. If desired, an additional
colorant, preferably a disperse dye, may be added to this
paste, with the disperse dye being provided primarily to
dye the disperse dyeable nylon or polyester fibers of the
flocked fabric.
Preferably, the Hycar 26419 is made up in a solution
so that it forms a soft polymer, that is with Tg of about
30. In the process, the latex solution is added to the
thickener and mixed together. Then, the melamine solution
is added, followed by the catalyst. Then, the viscosity is
* (trademarks)
WO 92/20524 fL'fl US92/04363
~~~~J~~~~
checked and if too low, additional thickener is added to
raise the viscosity to 1.5,000 +/-- 3,000 centipoise. This
is followed by the addition of the resisting agent and the
titanium dioxide. Agitation continues for 5 minutes or so
to assure thorough mixing. A further viscosity check is
undertaken and an additional thickener is added if
necessary to raise the viscosity. This thickener is
desirable for its good hysteresis properties, such that
under a shear, it will readily flow and then return quickly
to a viscous state. This characteristic is very helpful in
screen printing, so that the print paste mill be readily
applied to the fabric, but then not m~.grate once it is
applied.
The print paste described above is used for one or
more colors in a mufti-color wet-on°wet printing process,
such as a rotary screen or flatbed printing process.
Suitable apparatus f or carrying out the process is commonly
available in the textile industry, such as equipment
available from ~ohannes Zimmer Maschin of Klagenfurt,
Austria. Tf desired; multiple stages of the printing
operation may be provided with a print paste according to
this formulation or only one color may be with this
formulation, with other stages being provided witlx more
conventional print paste. Desirably, a last stage provides
a blotch coverage, either a fitted blotch or a full blotch.
Particularly with a full blotch, the resist agent which has
been added to the print paste should be selected to resist
fixation of the dyestuff of the blotch.
The fabr~.c, having had the dyestuff applied in its
patterns according to the various stages of the printing
apparatus and the blotch, is then driedyto reduce further
migration of dyes. Depending on the nature of the other
dyes applied, either the fabric is cured or fixed. When
the other dares are acid dyes and other dyes suitably fixed
by steaming, it is desirable to steam the fabric to fix
those dyes. The resist in the print paste described above
will prevent substantial fixata.on of the dyes from the
CA 02103451 2001-09-06
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blotch in the area of the print paste. Following fixation
of those dyes, the print paste described above can be cured
by exposure to dry heat at about 300-305 degrees Fahrenheit
for three minutes. The curing causes the cross-linking of
the melamine and latex to securely bond the particulate
colorant to the fibers of the flocked fabric. The melamine
and latex will support higher temperatures and cure faster,
typically temperatures up to 350 degrees Fahrenheit, but
such hot temperatures can have deleterious effects on the
fibers, so that slower fixation at the lower temperature is
preferred. The proportion and nature of the catalyst added
will also affect the curing rate.
The fabric is desirably cured by passing through a
tenter frame operating at a high enough temperature, so its
residence time is effective to achieve curing of the binder
system.
The cured fabric is then scoured to remove unfixed
dye, including soaping in an alkali treatment. The fabric
is then provided with a durable softener, preferably an
amino functional silicone, followed by brushing with a
nylon bristle brush to raise and smooth the nap.
It has also been found that the curing step can
precede fixing.
In another preferred embodiment, the print paste
binder system is made up of a hydroxy propyl methyl
cellulose (HPMC), such as Methocel K4MS* available from Dow
Chemical Co. of Midland, Michigan, a hydroxyethyl cellulose
(HEC) such as QP300* available from Union Carbide Corp. of
South Charleston, West Virginia. The preferred catalyst is
again PTSA along with 92~ water, to make a stock paste.
This stock paste is made by first adding the HPMC and HEC
to the water slowly under medium agitation. Then aqueous
ammonia is added to raise the pH to 9.0 +/- ,5 followed by
the addition of the melamine resin and the catalyst.
To this stock paste is then added a metallic liquid in
a pearlescent pigment. Suitable pigments are pearlescent
particles available from EM Industries of Hawthorne, NY.
* (trademarks)
CA 02103451 2001-09-06
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Metals such as particulate gold or bronze available for
M.R. Hooth of Ashland, Massachusetts may also be used.
This print paste can be used like the other, although
it desirably is applied as the last color or just before
the blotch in the wet-on-wet process, so that the print
paste is not adulterated with other materials. This
enhances the brilliance of the metallic material being
applied.
One of the advantages of use of the 957* thickener is
that when its pH is 9 or so, it is highly viscous, as
desired for its role as a print paste. When dried,
however, its pH drops to about 2, which helps to fix the
acid dye in the nylon.
One of the advantages of the HPMC for use with the
gold printing is that as it dries, its viscosity increases,
which helps to raise the gold to the surface of the fibers
so that it stands out and is more visible. This is to be
contrasted with the role of most other thickeners which
lose viscosity as they are heated and would tend to permit
the gold to drop down toward the substrate where it would
be less visible. Additionally, HPMC and HEC do not dry out
rapidly on the printing screens, so that they do not lose
their consistency over an extended printing run.
The following formulation has been found to be
desirable as a stock paste for gold printing (all
percentages by weight):
0.5~ methocel K4MS*
3.5 ~ QP 300
3.0 $ Cyrez 963*
0.5$ PTSA 10$ solution
92~ water
Desirably, this stock paste is mixed 50/50 with the
Hycar 26419 to make the print paste. The print paste may
be combined in a 80:20 proportion with metallic liquid to
make the print paste.
An alternative stock solution for gold printing is as
follows
* (trademarks)
CA 02103451 2001-09-06
9
8.8 lbs. QP300
1.1 1b. HPMC
4.4 1b. Cyrez 963
2.2 1b. PTSA 10$ solution
203.5 1b. water
This stock solution can be blended with the gold and
the Hycar 26419 in the range of 20-44 lbs. of gold, 99-88
lbs. of stock and 99-88 lbs. of 26419.
The same stock solution can be used for the titanium
dioxide printing using a formulation of 44 lbs. of titanium
dioxide, 77 lbs. of stock, 77 lbs. of 26419, and 22 lbs. of
Thiotan resist.
For the printing of colors, 187 lbs. of stock can be
combined with 22 lbs. of 26419, 11 lbs. of titanium dioxide
and the amount dyestuff as desired to make a print paste.
The relative portions of the melamine latex binder and
colorant compared with the thickener will affect the hand
of the finished product. If desired to make a distinctly
stiff hand, as may be desired to simulate embossed outline
lines in the patterned fabric, a formulation of 20$
titanium dioxide and 50~ binder, along with approximately
30~ thickener can be used. A softer hand is obtained with
a 5~ titanium dioxide, 10$ binder and 10~ resist
formulation. The resist material tends to provide softness
as well as resisting properties.
The fabric made according to the present invention is
very wear-resistant and suitable for use as upholstery
fabric. The fabrics printed with the gold have been tested
in a Wyzenbeek tester for up to 15,000 cycles with only
very little wear being experienced.
The printing screens used with the above formulation
will, of course, be dependent upon the particulate size
being used, although there has been found that a 60 mesh
screen is suitable for printing with the titanium dioxide,
but the gold or pearlescent materials require about a 40
mesh screen.
* (trademarks)
WO 92/20524 PGT/~.JS92/04363
~1~J ~~~ 10
The binder system of the present invention has been
used with conventional pigmented materials with limited
success. Apparently, the pigments appear not to be bound
to the fabric as strongly as the opaque particulate
colorants.
~ne particularly preferred embodiment of the invention
uses various positions of the printing mechanism to print
various colors. Each color is provided by the print paste
in which the titanium dioxide provides whiteness to the
fibers. A disperse dye in each pra.nt pasty penetrates the
nylon fibers of the fahric to dye them a calor which is
highlighted by the adhered titanium d3.oxide. This pro~rides
a much brighter and luminous print, even when an overprint
~ of blotch follows.
1S Typically, by the tame the fabric has gone through all
of the stages cf the printing mechanism, it has 100~~.80~
wet pickup.
The fabrics printed according to this invention are
readily washable a~xd dryacleanable.
The photographs making up the drawings of this
application illustrate the effects obtainable with the
invention and distinguish them from those obtained with the
prior art. Figures l and 2 are photographs of prior art
fabrics in which the coloration is applied to the fabric an
conventional fashion: The thus dyed fabric is discharge
printed with discharge print paste and gold, which shows up
as the highlighted lines in the pattern in both
photographs. As can be seen, the background coloration is
muted, diffuse and not particularly distinctive. This does
result in a highlighted gold, but it is an expensive
procedure to make such a second application to already dyed
fabric .
The fabric of Figure 3 is made in accordance with the
invention in which the whites lines apparent in the pattern
are applied using a white print piste as described above
and the coloration is applied with conventional print
paste, all in a single pass through a rotary screen
Sl.l~t~~T1'IrLD°~"~ S~°I~~T
CA 02103451 2001-09-06
IZ
printer. As can be appreciated from viewing the
photograph, the pattern is muted, but is highlighted by the
strong opaque particulate colorant lines put down using the
present invention. This provides a brilliant look to the
otherwise muted fabric. In addition, the particulate
material as adhered to the fibers causes them to have a
slightly different texture than the other surface of the
napped fabric to provide an interesting tactile effect, as
well as the visual aesthetics.
The photograph of Figure 4 illustrates a fabric
printed with a generally black blotch and overprinted in a
wet-on-wet process with a relatively random gold spatter,
using a gold print paste as described above. This results
in a bold looking fabric with the black background being
highlighted with the brilliant gold surface. Also seen in
the photograph of Figure 4 is a strip of the fabric which
has been subjected to 15,000 cycles in a Wyzenbeek~abrasion
test. Almost no change in the gold pattern can be seen in
the photograph. The actual fabric does show a bit more
wear than is apparent in the photograph, but still the
degree of wear is quite minimal, illustrating the strong
binding of the gold particulate material to the fibers.
Figure 5 is a photograph of another fabric made in
accordance with the invention in which all of the pattern
print pastes are made using formulations in accordance with
the invention, with a black blotch of conventional
formulation. The coloration of the flower petals and
leaves shown in the photograph is made using a white print
paste according to the invention, dyed with disperse dyes
to dye the fibers to which the white is adhered. The
resulting coloration is much more brilliant and sharp than
the corresponding coloration seen in Figures 1 or 2 which
show the prior art fabrics. The coloration is provided in
something of a rectilinear pattern, as part of the pattern,
rather than as an artifact of the printing process . The
outline in the fabric surrounding the leaves and flower
* (trademark)
WCl 92/20524 P~'IUS92/04363
C\ .j c
~.:.~ ~c.~ ~c~~ 12
petals is made with a gold particulate according to the
invention as described above.
Figure 6 is a photograph of yet another fabric in
accordance with the invention in which all of the
coloration is made using the invention, but with a
conventional black blotch. Again, the white printing
formulation according to the invention as described above
was used at various stages in the wet-on-wet machine, with,
disperse dyes to provide the color in the pattern. This
was overprinted with a black blotch of conventional
formulation. The result is a striking print in which line
detail of the colors is discernible, especially seen in the
horizontal and vertical lines in the background of the
~.w fabric. The print has strang coloration end brilli.an~
color, unlike the muted and diffuse colors of the prior art
prints of f'igu~e~ ~. and 2.
As can be appreciated, the invention provides numerous
possibilities for effecting brilliant new print colors for
velvets; flocks and other napped fabrics, with or without
a blotch overprint.
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