Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
COMPOSITION AND METHOD FOR RHEOLOGY CONTROLLED PRINTING OF
FABRIC AND CARPET
BACKGROUND OF THE INVENTION
The process of textile printing is utilized in a number
of different industries, including the production of
carpeting as well as fabrics for clothing, bedding and
draperies. It is common to divide textile printing in to
fabric printing and carpet printing, since while the
printing principles are the same, the natures of the two
types of textiles causes some variations in procedure.
Fabric printing involves the transfer of colorants
(dyes) to fabric (which is defined for the purposes of this
invention as relatively smooth flat textiles) and differs
from conventional fabric "dyeing." In conventional dyeing
processes the object i~ to impart uniform color throughout
the fabric, while in fabric printing the object is to place
(KEL2RPAT.E12)
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a recognizable colored design on the fabric or to impart
color to only a limited area of the fabric.
Fabric printing involves a number of problems not found
in conventional dyeing processes. Every design is formed of
discreet lines and limited areas of color which must be
clearly defined. commonly designs involve a plurality of
colors, each of which must be clearly separated from the
other colors of the design. Thus it is necessary for a
printing composition to be able to produce "fine line
definition" in~ which the individual lines of the design are
clearly and sharply, defined with no significant "bleeding'°
or "smearing" which ,would detract from the clarity of the
t.
line and the sharpness~of the design. The same is true of
areas of color, which must have precise boundaries and, in
"wet-on-wet" printing processes, not allow one color to
bleed into a neighboring color.
Also of importance is the degree of fabric penetration
of an individual colorant. While with conventional dyeing
it is desirable to have the color penetrate completely
through the fabric so that both sides of a fabric axe
equally and thoroughly colored, with fabric printing the
opposite is true. Normally in fabric printing the fabric
designer wishes to limit the printing to one side of the
fabric so that the printed designs either do not appear at
all when the fabric is viewed from the apposite side (as in
carpeting and some clothing) or that the visibility of the
design is distinctly subdued when viewed from the opposite
side of the fabric (as in some bedding). However, it is of
course still important that the printed design penetrate or
adhere sufficiently to the application side of the fabric
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such that normal wearing, washing and other intended uses of
the fabric will not significantly degrade the quality and
appearance of the design.
Carpet printing is basically similar, but since carpet
is (for the purposes of this invention) considered to be a
relatively thick textile with a clearly defined pile, some
practical aspects of the printing are different from those
of fabric printing. Principally, it is important in carpet
printing to insure that the colorant penetrates into the
pile down to the base of the carpet without spreading
laterally; i.e., that it retains the pattern or color area
definition. It must also have a higher degree of rheologic
and heat stability so that the dye does not run off the tops
of the pile fibers when the dyes are fixed on the carpet by
conventional steaming.
The colorant compositions may be applied by a variety
of different devices, depending on the particular industry
and type of fabric involved. Commonly one uses rotary
printing presses, in which a colorant paste is forced
through a porous pattern in contact with the fabric, in a
manner analogous to silk screen printing, fox the flat
fabrics. Carpet printing is often done with devices such as
jet printing machines in which the colorant composition is
projected in a narrowly defined jet against the fabric and
the printing head follows a pre-defined path to "draw" the
design on the carpet and cause the dye to penetrate into the
pile. The jet printers themselves may be of two different
types; in one type the stream of colorant forming the jet
runs continuously and the stream is diverted mechanically or
pneumatically from the fabric into a recycle path as the
[KEL2RPAT.E12]
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printing head traverses portions of the fabric where no
design is desired, while in the other the colorant jet is
turned on as the head passes the areas of the fabric where
the design is to be imparted and turned off while the jet
traverses areas of the fabric where no design is to be
placed.
The dyes themselves can be of different compositions.
One principal class of dyes widely used is the "reactive"
dyes, which are dye compounds which react chemically with
the fibers of the fabric, thus forming a permanent color
pattern, and which are preferentially used with natural
fiber textiles. Another common class is the acid dyes, used
principally with synthetic fiber textiles.
It will beg evident from the above consideration that
rheology control of colorant compositions is of utmost
significance, in order to allow the colorant compositions to
be utilized in a variety of different application devices
and to yield fabric and carpet designs which are colorfast,
sharply defined and have the requisite degree of
penetration.
In the past, however, only a few types of colorant
composition exhibited a wide range of these properties. It
was often found that rheology control components
incorporated into colorant compositions were usable only in
certain types of printing apparatus or with certain types of
textiles or in combination with limited numbers of dyes.
Further, when a control component had relatively short flow
properties and fast shear recovery rate, it would not
provide adequate levelinn of the composition, while another
component with relatively long flow properties and slow
[KEL2RPAT.E12]
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shear recovery rate would lead to poor line definition and
was difficult to use in "on/off" types of jet printing
devices. Also, some control components are also excessively
reactive with the dye compounds themselves, such that when
the colorant composition is applied to the textile a portion
of the dye reacts preferentially with the rheology control
component rather than with the fabric, so that when the
fabric is later washed that portion of the dye is removed
from the textile leaving a significantly degraded design and
wasting substantial amounts of dye. Since the dye is
commonly the most expensive part of any colorant
composition, this not only results in a poorly printed
product but also is quite uneconomical.
It would therefore be of significant value to have
rheology control agents which can be incorporated into
fabric and carpet printing compositions and which will allow
for fine line definition, essentially full color transfer to
the textile and versatility of use in a variety of different
printing devices. It is an object of this invention to
provide such rheology control agents and colorant
compositions incorporating such agents which are useful in a
wide variety of fabric and carpet printing applications.
BRIEF SUMMARY OF THE INVENTION
In one aspect the invention herein resides in a
composition for controlling rheology of an aqueous dye which
composition comprises 1-30 parts, preferably 2-25 parts, and
more preferably 5-20 parts, of. a gum selected from the group
consisting of xanthan gum, rhamsan gum, welan gum and
[KEL2RPAT.E12J
K-2097
mixtures thereof and 70-99 parts, preferably 75-98 parts,
and more preferably 80-95 parts, of a water soluble
polysaccharide having alginate equivalent theology,
preferably an alginate. (All percentages and parts defined
herein are by weight unless stated to be otherwise.)
In another aspect the invention resides in a color
imparting composition for fabric printing which comprises
90-99% of an aqueous dye component and 1-10% of a theology
control component, the theology control component comprising
1-30 parts, preferably 2-20 parts, and more preferably 5-15
parts, of a gum selected from the group consisting of
xanthan gum, rhamsan gum, welan gum and mixtures thereof and
70-99 parts, preferably 80-98 parts, and more preferably 80-
95 parts, of a water soluble polysaccharide having alginate
equivalent theology, preferably an alginate.
In yet another aspect the invention resides in a color
imparting composition for carpet printing which comprises
90-99% of an aqueous dye component and 1-10% of a theology
control component, the theology control component comprising
1-30 parts, preferably 5-30 parts, and more preferably 8-20
parts, of a gum selected from the group consisting of
xanthan gum, rhamsan gum, welan gum and mixtures thereof and
70-99 parts, preferably 70-95 parts, and mare preferably 80-
92 parts, of a water soluble polysaccharide having alginate
equivalent theology, preferably an alginate.
In yet another aspect the invention resides in a method
of controlling the theology of an aqueous dye composition
which comprises incorporating into the composition 1-l0% of
a theology control component which comprises 1-30 parts,
preferably 2-25 parts, and more preferably 5-20 parts, of a
(KEL2RPAT.R12)
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gum selected from the group consisting of xanthan gum,
rhamsan gum, welan gum and mixtures thereof and 70-99 parts,
preferably 75-98 parts, and more preferably 80-95 parts, of
a water soluble polysaccharide having alginate equivalent
theology, preferably an alginate.
DETAILED DESCRIPTION
The theology control agents of the present invention,
and the novel and versatile colorant compositions which they
produce, are based on the unexpected discovery that
combinations of components which are themselves individually
of limited utility or even not useful as colorant component
theology control agents are when combined in specific
proportions able to form highly effective theology control
agents for a wide variety of colorant compositions usef~;l in
many different applications and with different types of
printing equipment.
The first component of the compositions herein is a gum
selected from the group consisting of xanthan gum, rhamsan
gum, welan gum or mixtures thereof.
By t'~e term "xanthan gum" as used herein is meant the
extracellularly produced gum made by the heteropoly-
saccharide-producing bacterium Xanthomonas campestris by the
whole culture fermentation of a variety of conditions of a
medium comprising a fermentable carbohydrate, a nitrogen
source and other appropriate nutrients. Examples of
commercially available ,xanthan gum are "KELTROLR T",
"KELTROLR F", "KELZAIdR AR" and "IfELZANR", available from
Kelco Division of Merck & Co., Inc.
[KEL2RPAT.E12)
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Processes for producing xanthan gum are well known in
the art and are described in a number of patents including
U.S. Patents Nos. 9,316,012, 4,352,882, 4,375,512,
3,671,398, 3,433,708, 3,271,267,,3,594,280, 3,591,578,
3,391,061, 3,020,206, 3,481,899 and 3,391,060 as Well aS
British Patent No. 1,448,645.
A preferred form of xanthan gum utilized in the
invention is that which has been clarified by any of several
known clarification processes. Clarified xanthan gum such
as "KELTROLR T" and "K5B143" (products of Kelco Division of
Merck and Company, Inc.) is commercially available. As
defined herein clarified xanthan gum is that which has a 1%
(wt./vol.) solution (deionized water) transmittance of not
less than 85%, measured on a Bausch & Lomb "SPECTRONIC"
photometer, model 21 (600 mm., 25°C, 10 mm. cell).
Also useful in this invention is welan gum. Welan gum
is a water-soluble polysaccharide produced by the
fermentation of Alcalicxenes snn. Welan gum is stable over a
wide range of viscosities and at temperatures up to about
150°C (300°F). Welan gum is described in U.S. Patent No.
4,342,866. A typical welan gum is that available
commercially under the trade designation "K1A96" from Kelco
Division of Merck & Co., Inc.
The third gum useful in the present invention is
rhamsan gum. Rhamsan gum is a microbial polysaccharide also
produced from Alcaliaenes spp. which is highly
pseudoplastic, has a stable viscosity over a range of pH of
2-12 and at temperatures up to about 100'C (212°F) and is
compatible with high concentrations of salt. Rhamsan gum is
described in U.S. Patent 190. 4,401,760. Rhamsan gum is
[KEL2RPAT.E12]
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commercially available; a typical example is a gum sold
under the trade designation "K1A17.2" by Kelco Division of
Merck & Co., Inc.
The viscosity of the gum to be used will be a simple
matter of selection based on the nature of the colorant
composition system into which the rheology control agent is
to be incorporated.
The other principal component of the compositions of
this invention is a water-soluble polysaccharide having
"alginate equivalent rheology." By this term is meant a
polysaccharide whose rheologic properties in these
compositions is substantially equivalent to the rheologic
properties which would be exhibited by an alginate. The
preferred polysaccharides are the alginates themselves,
because they are the only relevant class of polysaccharides
which are useful with all of the applicable dyes, i.e., are
the only class of polysaccharides which do not react With
the reactive dyes. Other polysaccharides within the class
of "alginate equivalent rheology" materials are, however,
useful faith other dyes, especially the acid dyes, and are
therefore within the scope of this invention. Suitable
polysaccharides include alginates (as noted), starches,
cellulosic ethers, guar gum arid mixtures thereof.
There are a wide variety of alginates useful in this
invention. These are described in detail by I.W. Cottrell
and P. Kovacs in "Alginates," as Chapter 2 of Davidson, ed.,
Handbook of Water-Soluble Cums and Resins (1980). Most
preferred herein are the sodium alginates, such as those
sold commercially under the' trademarks ICELTEXR and 1CELGINR
by Kelco Division of Merc)c & Co., Inc.
[KEL2RPAT.E12]
K-2097
The cellulosic ethers, guar gum and starches are alse
widely described in the literature. The Davidson text,
supra, has typical disclosures of these materials: see J.K.
Seaman, "Guar Gum," Chapter 6: G.M. Powell,"Hydroxy-
5 ethylcellulose," Chapter 12; and M.W. Rutenberg, "Starch and
its Modifications," Chapter 22.
In the present invention the polysaccharide and gum
will be present in a weight ratio in the range of 99-70
parts of polysaccharide to 1-30 parts of gum. Preferably
10 the ratio will be in the range of 98-75 parts of
polysaccharide to 2-25 parts of gum, and more preferably in
the range of 95-80 parts of polysaccharide to 5-20 parts of
gum. The entire polysaccharide/gum rheology control
component will be present as from 1-10%. preferably 2-8%, of
the print paste composition. As wall be discussed below,
the specific preferred ranges will vary slightly depending
on whether fabric printing or carpet printing is involved.
The particular dyes used in the colorant compositions
of this invention will be chosen on the basis of the type of
fabric to be colored and compatibility with the remaining
components of the print paste composition. There are many
types of dyes useful for textile printing; various classes
of dyes are described in Kulkarni et al., Textile Dyeina
Operations (1986) and in Venkataraman, The Chemistry of
Synthetic Dyes viols. IV and VIII (1972). Most preferred
for the print pastes of this' invention are the reactive
dyes, which derive their name from the fact that they react
covalently with many major natural textile fibers, including
wool, the cellulosic fibers and sill;. The reactive dyes
include colored acid ch).orides, vinyl sulfones and the vinyl
(KEL2RPAT.E12J
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sulfone and triazine derivatives of anthrac~uinones,
including the mono- and dichlorotriazinyl compounds. The
reactive dyes are described in detail in Kulkarni et al.,
su ra Section 6.7 and in Venkataraman, su ra vol. VI.
Another preferred class of the dyes.is the acid dyes, which
are so named because they are normally applied in organic or
inorganic acid dyeing solutions. These dyes generally are
anionic dyes with relatively low molecular weight which
contain one to three sulfonic acid groups and are used as
salts, such as sodium salts. The majority of the acid dyes
are azo, anthraquinone and triarylmethane dyes. They are
described in detail in Yulkarni et al., su ra Section 6.2.
They find particular application with the synthetic fibers
such as nylon. The particular dye of choice for any
specific application may be readily selected by one skilled
in the art by routine procedures. The dye will normally be
present as about 2-4% of the colorant composition.
The colorant compositions also commonly contain small
amounts of additional materials as dispersants, stabilizers,
dye solubilizers and so forth. The rheology control
component herein preferably contains sodium
hexametaphosphate (sold commercially under the trademark
CALGONR by Calgon Corporation) as a sequestrant for calcium
in the water present in the composition, to prevent unwanted
gellation of the gum or polysaccharide. The amount of the
sodium hexametaphosphate present will be on the order of
about 20-30% of the polxsaccharide. Other sequestrants
include salts of ethylenediaminetetraacetic acid (EDTA) and
sodium citrate. In addition, the composition can contain
materials such as m-nitrobenzene sulfonate (sold
[KEL2RPAT.E12]
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commercially under the trademark LUDIGOLR) as an anti-
reductive agent for the dye in an amount of about 1.0-1.5%
of the composition, urea (10-12% of the composition) and
sodium bicarbonate (about 2% of the composition.)
As noted above, the particular needs of fabric printing
and carpet printing Iead to slightly different preferred
ranges of components in the theology control agents of this
invention. For fabric printing the theology control
component will preferably comprise 2-20 parts, more
preferably 5-15 parts, of gum and 80-98 parts, more
preferably 80-95 parts, of the water soluble polysaccharide.
For carpet printing the theology control component will
preferably comprise 5-30 parts, more preferably 8-20 parts,
of gum and 70-95 parts, more preferably 80-92 parts, of the
water soluble polysaccharide.
It is believed that the compositions herein are
effective because under the conditions of use the gum is
more pseudoplastic than the polysaccharide (i.e., it has a
higher viscosity at a given temperature). This in turn
imparts a greater rheologic stability to the composition
than would be obtained with the polysaccharide alone. The
dye compositions are usually applied at ambient temperature.
However, the dyes are then fixed on the fabric or carpet by
steaming (usually at about 220°F/105°C for about ten
minutes). Under these latter conditions, the composition
remains properly in position an the textile so that the dye
color does not migrate from the tops of the fibers.
Colorant compositions incorporating the theology
control agents of this invention were tested in a variety of
fabric printing laboratory processes which accurately
[KEL2RPAT.E12]
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simulate the effects to be obtained in commercial processes.
In a first set of experiments pressure printing effects were
measured, using a production-size~commercial rotary screen
print machine. Cotton fabric having .a weight of 1G6 g~m2
was printed with an 80 mesh screen using several different
test compositions and an alginate thickener as a control.
Pressure of the squeegee on the rotary screen was adjusted
for each run to obtain equal pick-up of each test print
paste as compared to the control. In addition to the
thickener and the dye, the compositions also included water
and small conventional amounts of sodium hexametaphosphate,
m-nitrobenzene sulfonate and sodium bicarbonate. The dye
used was a Prussian blue commercial reactive dye (from
Imperial Chemical Industries). Following application of
print paste in each run, the printed fabrics were dried and
then fixed with steam fixation for seven minutes at 1o5°C
followed by hand washing to remove excess print paste and
then dried prior to print evaluation.
In Tables I and II below the data labeled "dE"
represent the measure of color differences for the test
samples as compared .to a standard, based on tristimulus
values, according to AATCC Test Method 153-1985 AATCC
Technical Manual/1987 page 272). A higher value indicates
greater color acquisition by the textile. The data labeled
"dL" represent the measure of difference of darkness of the
pattern imparted to the textile, and is determined by
subtracting the "da" and "db" color components of "dE" (see
AATCC Test Method 153-1985) from the "dE" value fox each
sample. A negative value means that the test sample was
darker than the standard; i_.e., that it had more dye
[KEL2RPAT.E12)
~~~"~~~.~
K-2097
imparted to it. Viscosities reported for the compositions
were measured with a Brookfield "RVT" viscometer operating
at 20 rpm at 20°C with a No. 2 spindle. The comparative
designations stated are "sup." for "superior," "eq." for
"equal" and "inf." for " inferior. An "S." preceding a
designation indicates "slightly."
[KEL2RPAT.E12]
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-16- K-2097
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17- K-2097
It will be evident from these data that the blends of
this invention provide a printed fabric which has
penetration, levelness and definition properties which are
as good as or better than the properties of the alginate
thickened control. In addition the handle of the printed
fabric is equal to that of fabrics printed with the control.
Most importantly, however, the data show a substantially
consistent improvement in the equivalent dye and color
values imparted to the fabrics. This provides two alternate
and substantial benefits: for the same amount of dye used
an improved and increased color value can be imparted to the
fabric or, alternatively, the same degree of color value can
be imparted to the fabric by using significantly less dye in
the print paste. Also of particular importance is the
superior control of print paste penetration that the
compositions of this invention uniformly provide.
'fhe compositions of the present invention were also run
in experimental carpet printing tests using jet printing
machines of both the air diversion jet type and the off/on
jet type. Rheology control components similar to those
reported above were formed of alginate and xanthan gum in
ratios of 90:10 and 85:15 and run in series with control
materials having only alginate as the thickener. The
theology control components also contained small amounts of
sodium hexametaphosphate to provide ionic stability in the
presence of the acidic dye in the colorant composition. In
addition the runs were compared against prior art colorants
used in the jet printing devices in which the thickener is a
starch. In all cases notable improvement in. rheologic
control resulting in improved mint definition and color was
[KEL2RPAT.E12)
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observed.
It has previously been recognized that the use of
cationic dyes in print pastes which also contain xanthan gum
can cause unacceptable precipitation or gelation of the
xanthan gum. Additions of small amounts of surfactants to
the blends for the experimental runs, as outlined by the
prior art, were sufficient to eliminate such precipitation
or gelation.
In this series of runs the products shown in Table III
below were tested in a jet printer to lay out plaid, floral,
geometric and block patterns on carpeting.
Table III
RUN: 25 26 27 28 29
Alginate 100 85 85 85 70
Xanthan Gum --- Z5 15 15 30
Concentration, % 2.0 0.65 0.75 0.60 0.75
Tailing of the colorant composition was more likely
when the ratio of alginate to gum was near 70:30; as the
proportion of alginate increased, the occurrence of tailing
decreased. Best results were obtained when the ratio was
approximately 85:15.
It will be evident that there are many embodiments of
this invention which, while not expressly set forth above,
are clearly within the scope and spirit of the invention.
The above description i.s therefore to be considered
[KEL2RPAT.E12]
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19 K--2097
exemplary only, and the scope of the invention is to be
limited only by the appended claims.
[ KEL2RP~1T. E12
