Note: Descriptions are shown in the official language in which they were submitted.
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PIGMENT FLUSHING
Background of the Invention
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1. Field of the Invent on
This invention relates to new and useful improve-
ments in non-aqueous pigment dispersions. It relates par-
ticularly to the transfer of a pigment from an aqueous pulp or
presscake directly into organic vehicles by an operation
known to those skilled in the art as flushing. It relates
more particularly to agents for the flushing of an organic
pigment to provide a low viscosity, shelf-stable dispersion
having good tint strength.
2. D scription o h _ r or Art
The flushing of pigment presscakes. in order to
disperse the pigment in an organic vehicle, is well known.
The transfer may be effected in some cases by merely kneading
the press cake and vehicle together until substantially all
the water has separated. In most prior art methods, a surface-
active agent is added to facilitate the transfer. There have
been many attempts in the prior art to find different surface-
active agents or surfactants, generally referred to as flushingaids, in order to solve specific problems such as the large
amount of mechanical work required, a lack of tinting strength
of the flushed color, and the like. Many attempts have been
made to find a flushing aid for an organic pigment which would
provide a flushed color having a low viscosity both initially
and during long term storage. The search has been complicated
by the further requirement that the flushing aid should have
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little or no detrimental effect on the tint strength of the
flushed color.
Sulfonates prepared from various organic materials
have been tried as flushing aids. Reference is made in U.S.
Patent No. 2,120.588 to the use of a condensation product of
naphthalene sulfonic acid with formaldehyde. Petroleum
sulfonates have long been used as dispersing agents in the
flushing of pigment presscakes In some instances, however
the flushed color obtained has a high initial viscosity and a
poor shelf stability, i.e., the viscosity increases to an
unacceptably high value upon storage at ambient temperatures.
The use of cationic surface-active materials such as
long-chain aliphatic quaternary ammonium, long-chain sulfonium.
and long-chain phosphonium compounds as flushing aids, is
taught in U.S. Patent No. 2,192 954. In this patent. however,
it is taught that such cationic material sometimes cause the
formation of a water-in-oil emulsion which prevents the
separation of the bulk of the water. In order to overcome
that problem, U.S~ Patent No. 2,219,395 teaches the addition
of a sulfonated fatty oil, a sulfonated aromatic compound or a
fatty alcohol sulfate to the kneaded mass of pigment, water,
oil and cationic material in order to reverse the objection-
able water-in-oil emulsion.
U.S. Patent 3,256,202 discloses improved surface-
active agents including salts of sulfated hydrocarbon alcohols
derived from sperm oil and suggests that they may be valuable
as dispersants for dyes, pigments, etc. However, there is no
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disclosure of the use of sulfated or sulfonated sperm oils in
a flushing process. Further, this patent is directed to
mixtures of sulfated aliphatic hydrocarbon alcohols. These
mixtures consist essentially of at least one salt of a sulfated
lower aliphatic alcohol having from 1 to 4 carbon atoms and at
least one salt of a sulfated higher aliphatic alcohol having
at least 16 carbon atoms. Sulfated sperm oil is listed
as one of the higher aliphatic alcohols. Mixture of the
latter with the former is treated as essential to the invention.
U.S. 3,449,261 discloses a mixture of sulfonated
hydrocarbons such as spermiceti oil and tris(butoxyethyl)phos-
phate in dyeing operations. However, the disclosure is for
use in dyeing textiles as a low-foaming wetting agent for the
textile and not as a flushing aid.
Accordingly, it is a purpose of the instant inven-
tion to provide for flushing an organic pigment whereby a
flushed color having a low initial viscosity, good shelf
stabilityr and good tint strength will be available to the
printing ink and coating industries.
Summary of _he_I vention
This invention relates to the method for transfering
organic pigment from an aqueous pulp of the pigment to a
water-immiscible organic vehicle by mixing said aqueous pulp
and said vehicle until a major portion of the water present in
said pulp separates. In accordance with the instant invention,
at least one additive selected from the class consisting of
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sulfonated sperm oil, sulfated sperm oil, and mixtures thereof,
is incorporated with said pigment and said vehicle.
Description of the Preferred Embodiments
It has been discovered in accordance with the instant
invention that an organic pigment may be dispersed in a hydro-
phobic organic vehicle through the use of sulfonated sperm oil
or sulfated sperm oil or mixture thereof. The use of cationic
surface-active materials as per the disclosures of U.S. Patents
Nos. 2,192,854 and 2,219,395 is not necessary nor is the
inclusion of a salt of a sulfated lower aliphatic alcohol.
The method of this invention is particularly useful
with alkali blue pigments ranging from the green shades to the
red shades. The structure, manufacture, uses and properties of
alkali blue pigments are described by G. R. Buckwalter at pages
617 to 624 of the Handbook of Pigments, published by John Wiley
and Sons, 1972 edition. As described in the Handbook of
Pigments, an alkali blue pigment is in itself a water-insoluble
sulfonic acid or internal salt. The commercially pure pigment
is prepared by the addition of an acid to a solution of the
sodium salt. While the method and additive of this invention
are particularly suited for flushing an alkali blue pigment,
the invention is also applicable to other organic pigments such
as azo red, particularly Nos. 48, 52, and 57, diarylide AAA
yellow, particularly No. 12, and phthalocyanine blue, particu-
larly No. 15.
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The aqueous pulp of the pigment is the presscake
formed upon filtration of an aqueous slurry of the precipi-
tated pigment. The press cake still contains a large amount
of water. i.e., about 60 to 90 percent by weight. The propor-
tion of press cake to vehicle will have a very wide range
depending upon the concentration of pigment in the vehicle
that is ultimately desired and which may range from a very
small percentage of presscake to a very high percentage of
presscake.
Any of the hydrophobic organic vehicles that are
commonly used in printing ink and coating compositions may be
employed in the method and composition of this invention.
Such vehicles are represented by drying, semi-drying and
non-drying oils. litho varnishes, mineral oils, rosins,
dimerized rosins esters of dimerized rosins, aliphatic and
aromatic hydrocarbon resins, alkyl aromatic resins, maleic and
fumeric-modified rosin. phenolic resin, phenolic-modified
rosin esters, alkyd resins, urethane-modified alkyds! poly-
olefins. polyindenes. cumarone/indene resins, phthalate
esters, castor oil, fish oil, linseed oil, gloss varnishes,
and the various heat-set, quick-set and steam-set vehicle
systems.
The term "sulfonated sperm oil" as used herein means
either the sulfonic acid produced by the sulfonation of sperm
oil or the alkali metal or ammonium salt of the acid. The
sulfated sperm oil is an essentially neutral sulfate ester
produced by the action of sulfuric acid on sperm oil. Sperm
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oil, as is known to those skilled in the art. is a natural
product obtained from the sperm whale: the general composition
of which is as follows.
5.0 % Myristic acid C14
4.0 % Myristoleic acid C14
6.5 % Palmitic acid C16
26.5 % Palmitoleic acid C16
37.5 % Oleic acid C17
19.0 % Eicasapolyenoic acid C20
10 1.5 % Other acids C12-c24
The recent move to save whales has forced manu-
facturers to develop "synthetic oil". Such synthetic oils
have compositions substantially the same as the above and are
presently available on the market. A synthetic sulfated sperm
oil called AESS (aliphatic ester sulfate substitute) works
equally well with the instant invention. Accordingly the
terms "sulfonated sperm oil" and "sulfated sperm oil" as used
herein include products obtained from both the natural sperm
oil from the sperm whale and the synthetic sperm oil.
The additive or surfactant may be added to the
aqueous slurry of the precipitated pigment before filtration
thereof~ to the press cake directly, to the organic vehicle
before admixture with the presscake r to a mixture of the
vehicle and press cake. or to the mixture of vehicle and
pigment after the water is removed.
Generally the amount of additive employed is
from about 5 percent to about 40 percent of the dry weight of
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the pigment contained in the pulp or presscake. Preferably,
the amount is from about 10 percent to 25 percent of the
pigment's dry weight.
As previously pointed out, a mixture of the sul-
fonated sperm oil and the sulfated sperm oil may be used.
The two surfactants may be mixed in any proportion but an
especially useful mixture contains about 60 parts of sulfonate
to 40 parts of sulfate by weight.
Conventional flushing equipment such as high shear
homogenizers, a Kady mill, sigma-blade mixers and the like may
be used to mix the pulp, vehicle and additive. The mixing
is usually carried out at ambient temperature, for example,
about 70 to 85F. Higher temperatures up to about 200F may
be employed.
AS the mixing proceeds, the pigment surfaces become
receptive to the organic vehicle and water separates from the
aqueous pulp. This water is removed from the mixture by
decantation, centrifugation or other mechanical means. The
time required for the separation of the water, i.e., by weight
about 60 to 95 percent, preferably 75 to 95 percent, of the
water depends upon a number of factors. including the vis- -
cosity of the pulp which in turn is related to the amount
of pigment in said pulp, the temperature. the type and amount
of organic vehicle and the amount of flushing aid. Generally,
it will require about 15 to 150 minutes to separate the water.
The following examples are illustrative of the
~ethod and composition of this invention. All parts are by
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weight and all temperatures are in degrees Fahrenheit unless
otherwise indicated.
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Example 1
A presscake containing 500 parts (24 percent by
weight of the presscake) of a red shade alkali blue pigment is
divided into 6 equal portions. Two portions of the presscake
are mixed in a sigma blade mixer at room temperature (about
70) with 75 parts of the sodium salt of sperm oil sulfonic
acid sold under the trademark Eureka 400 by Atlas Refinery,
Inc. 125 parts of a 20:80 polyindene/fish oil vehicle
(Vehicle A). and 97 parts of a 30:70 polyindene/lithographic
varnish vehicle (Vehicle B). Frictional heat causes the
temperature to rise to about 75 after 30 minutes and 362
parts of water are decanted from the mixture. Another portion
of the presscake is added to the mixture along with 25 parts
of the Eureka 400 additive and 34 parts of Vehicle B. After
25 minutes, the temperature is 90 and 378 parts of water are
decanted. This is the maximum temperature. The remaining
three portions of presscake are charged separately along with
sufficient amounts of Vehicle B to bring the total of said
vehicle to 270 parts. About 85 percent of the water which was
present in the presscake is removed by the decanting process.
The mixture is then let down with 120 parts of a
triple O lithographic varnish [OOO Litho] and the dispersion
is mixed under reduced pressure to remove the residual water.
A hydrocarbon solvent ( 191 parts) sold under the trademark
Magie 520 by the Magie Brothers Company and 9 parts of a 25
percent solution of antioxidant in Magie 47 solvent are added
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and drying of the flushed color is completed under reduced
pressure to give 1280 parts of product.
_xample 2
A presscake containing 500 parts (24 percent by
weight of the presscake) of a red shade alkali blue pigment is
divided into 2 equal portions. One portion of the presscake
is mixed in a sigma blade mixer at room temperature (about
70) with 75 parts of sulfated sperm oil sold by Refined Onyx
company as Aliphatic Ester Sulphate, 125 parts of a 20:80
polyindene/fish oil vehicle (Vehicle A), and 182 parts of a
30:70 polyindene/lithographic varnish vehicle (Vehicle B).
Frictional heat causes the temperature to rise to about 86
after 30 minutes and 712 parts of water are decanted from the
mixture. The second portion of the presscake is divided into
three equal parts one of which is added to the mixture along
with 25 parts of the sulfonated sperm oil and 51 parts of
Vehicle B. After 25 minutes, the temperature is 95 and 253
parts of water are decanted. The temperature eventually
reached a maximum of 116. The remaining two portions of
presscake are charged separately along with sufficient amounts
of Vehicle B to bring the total of said vehicle to 270 parts.
About 90 percent of the water which was present in the press-
cake is removed by the decanting process.
The mixture is then let down with 120 parts of a
triple O lithographic varnish [OOO Litho] and the dispersion
is mixed uinder reduced pressure to remove the residual water.
A hydrocarbon solvent ( 191 parts) sold under the trademark
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Magie 520 by the Magie Brothers Company and 9 parts of a 25
percent solution of antioxidant in Magie 47 solvent are added
and drying of the flushed color is completed under reduced
pressure to give 1234 parts of product.
Example_3
A presscake containing 500 parts (24 percent by
weight of the presscake) of a red shade alkali blue pigment is
divided into 2 equal portions. One portion of the presscake
is mixed in a sigma blade mixer at room temperature (about
70) with 77 parts of a 60:40 mixture of the sodium salt of
sperm oil sulfonic acid sold under the trademark Eureka 400
and sulfated sperm oil described in Example 3, 125 parts of a
20:80 polyindene/fish oil vehicle (Vehicle A), and 166 parts
of a 30:70 polyindene/lithographic varnish vehicle (Vehicle
B). Frictional heat causes the temperature to rise to about
89 after 17 minutes and 600 parts of water are decanted from
the mixture. The second portion of the presscake is divided
into three parts, one of which is added to the mixture along
with 59 parts of Vehicle B. After 12 minutes, the temperature
is 90 and 294 grams of water are decanted from the mixture.
A second one-sixth part of the presscake is added to the
mixture along with 23 parts of the 60:40 mixture and 29 parts
of Vehicle B. After 26 minutes, the temperature is 100~ (the
maximum) and 270 parts of water are decanted. The remaining
one-sixth portion of presscake is charged along with 16 parts
of Vehicle B. About 87 percent of the water which was present
in the presscake is removed by the decanting process.
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The mixture is then let down with 120 parts of a
triple O lithographic varnish lOOO Litho] and the dispersion
is mixed under reduced pressure to remove the residual water.
A hydrocarbon solvent ( 191 parts) sold under the trademark
Magie 520 by the Magie Brothers Company and 9 parts of a 25
percent solution of antioxidant in Magie 47 solvent are added
and drying of the flushed color is completed under reduced
pressure to give 1265 parts of product.
Example 4
550
A presscake containing ~ parts (24 percent by
weight of the presscake) of a red shade alkali blue pigment is
divided into 6 equal portions. Two portions of the presscake
are mixed in a sig~a blade mixer at room temperature (about
70-) with 110 parts of synthetic sulphated sperm oil which is
essentially the same as the sulphated sperm oil of Example 3
except that synthetic sperm oil is employed in lieu of natural
sperm oil in manufacturing the product, 138 parts of a 20;80
polyindene/fish oil vehicle (Vehicle A), and 54 parts of a
30:70 polyindene/lithographic varnish vehicle (Vehicle B).
After 23 minutes 237 parts of water were decanted from the
mixture. m e remaining portions of presscake are charged
separately along with sufficient amounts of Vehicle B to bring
the total of said vehicle to 294 parts. About 80 percent of
the water which was present in the presscake was removed by
the decanting process.
The mixture is then let down with 132 parts of a
triple O lithographic varnish [OOO Litho] and the dispersion
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is mixed uinder reduced pressure to remove the residual water.
A hydrocarbon solvent (209 parts) sold under the trademark
Magie 520 by the Magie Brothers Company and 10 parts of a 25
percent solution of antioxidant in Magie 47 solvent are added
and drying of the flushed color is completed under reduced
pressure to give 1413 parts of product.
Example 5
Comparative Example
A presscake containing 500 parts (24 percent by
weight of the presscake) of a red shade alkali blue pigment is
divided into two equal portions. One portion of the presscake
is mixed in a sigma blade mixer at room temperature (about
70C) with 75 parts of a sulfonated naphthylenic petroleum
hydrocarbon sold by Emery Industries under the name Twitchell
Base 8911. 125 parts of a 20:80 polyindene/fish oil vehicle
(Vehicle A) and 179 parts of a 30:70 polyindene/ligho-
graphic varnish vehicle (Vehicle B). Frictional heat causes
the temperature to rise to about 90 after 25 minutes,
and 256 grams of water are decanted from the mixture. The
remaining half of the presscake is divided into three equal
parts, one of which is added to the mixture along with 87
parts of Vehicle B. After 20 minutes, the temperature is
100C and 531 parts of water are decanted. Another one-sixth
portion of the presscake is added to the mixture along with 25
parts of the sulfonated petroleum hydrocarbon. After five
minutes, the temperature is still 100 and 195 grams of water
is decanted. The remaining portion of the presscake is added
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to the mixture along with 4 parts of Vehicle B. After 90
minutes, 231 grams of water are decanted off and the tempera-
ture is about 110. About 77 percent of the water which was
present in the presscake is removed by the decanting process.
The mixture is then let down with 120 parts of a
triple 0 lithographic varnish [000 Litho] and the dispersion
is mixed under reduced pressure to remove the residual water.
A hydrocarbon solvent ( 191 parts) sold under the trademark
Magie 520 by the Magie Bros. Company and S parts of a 25
percent solution of antioxidant in Magie 47 solvent are added
and drying of the flush color is completed under reduced
pressure to give 1291 parts of product.
Table 1 shows the initial viscosity, the viscosity
after storage for three months at 120, the tint strength and
the bronze-tone of the products of Examples 1-5. The vis-
cosity of products was determined with a Laray viscometer and
the values are reported in poises. The tint strengths are
relative values and, therefore a tint strength of 100 is
assigned arbitrarily to the control product. The bronze tone
are also relatiave values wherein the lower the number, the
better the bronze tone.
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T ble I
Initial 3-Month Tint Bronze
Produc_Vi o _ tyViscosity Strength Tone
Example 153 77 104 6
Example 2151 162 100 5
Example 3150 176 98 4
Example 470 90 102 6
Example 5231 293 100 5
(control)
E_ample 6
A presscake containing 632 parts (24 percent by
weight of the presscake) of pigment red 57 is divided into 6
equal portions. Two portions of the presscake are mixed in a
sigma blade mixer at room temperature (about 70) with
65 parts of alkyd resin vehicle (Vehicle A), and 222 parts of
a 30;70 hydrocarbon solvent/rosin modified ester vehicle
(Vehicle B). The hydrocarbon solvent is sold under the
trademark Magie 47 by the Magie Bros. Co. The mixture is
heated whereby the temperature rises to about 150C
after 20 minutes and 535 parts of water are decanted from the
mixture. Another portion of ~he presscake is added to the
mixture along with 30 parts of a 40;60 Magie 47 solvent/alkyl
aromatic hydrocabon resin vehicle (Vehicle C). After 15
minutes, the temperature is 145~ and 256 parts of water are
decanted. The remaining three portions of presscake are
charged separately along with sufficient amounts of Vehicle C
to bring the total parts of said vehicle to 256 and the water
is decanted. Ninety eight parts of a 40:50 Magie 47/rosin
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vehicle~ and 86 parts of Vehicle C are added and the water
decanted. About 72 percent of the water which was present in
the presscake is removed by the decanting process. The
temperature reaches a maximum of 165. The mixture is tested
for shade at 180, 190~, 200 and 210 and the shades were
respectively very yellow, medium yellow, very slightly yellow
and very, very slightly yellow. The mixture is quenched with
57 parts Vehicle C.
The mixture is then let down with 281 parts of
Vehicle C and 48 parts of higher boiling alcohol. A hydro-
carbon solvent (108 parts) sold under the trademark Magie 47
by the Magie Brothers Company and 6 parts of a 25 percent
solution of antioxidant in Magie 47 solvent are added and
drying of the flushed color is completed under reduced
pressure to give 1810 parts of product. The viscosity of this
product was 15,202 poise as determined by a Laray viscometer.
Example 7
A presscake containing 632 parts (24 percent by
weight of the presscake) of pigment red 57 is divided into 6
equal portions~ Two portions of the presscake are mixed in a
sigma blade mixer at room temperature (about 70) with
65 parts of an alkyd resin vehicle (Vehicle A), and 222 parts
of a 30:70 hydrocarbon solvent/rosin modified ester vehicle
(Vehicle B). The hydrocarbon solvent is sold under the
trademark Magie 47 by the Magie ~ros Co. The mixture is
heated whereby the temperature rises to ~bout 140 after 20
minutes and 558 parts of water are decanted from the mixture.
Another portion of the presscake is added to the mixture along
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with 39 parts of a 40:60 Magie 47 solvent/alkyl aromatic
hydrocarbon resin vehicle (Vehicle C) After 20 minutes, the
temperature is 145 and 266 parts of water are decanted. The
remaining three portions of presscake are charged separately
along with sufficient amounts of Vehicle C to bring the total
parts of said vehicle to 256 and the water is decanted.
Ninety-eight parts of a 40:60 Magie 47/rosin vehicle, and 196
parts of Vehicle C are added and the water decanted. About
75.5 percent of the water which was present in the presscake
is removed by the decanting process. The temperature reaches
a maximum of 175. The mixture is tested for shade at 180,
190, 200, 205, 205, 215, and 220, and the shades were
respectively very yellow, medium yellow, very slightly yellow,
very slightly yellowr very very slightly yellow, very very
slightly yellow, and very very slightly yellow. The mixture
is quenched with 38 parts Vehicle C and 126 parts of AESS
synthetic sulfated sperm oil is added.
The mixture is then let down with 96 parts of
Vehicle C and 48 parts of higher boiling alcohol. A hydro-
carbon solvent (76 parts) sold under the trademark ~agie 47 bythe Magie Brothers Company and 6 parts of a 25 percent solu-
tion of antioxidant in Magie 47 solvent are added and drying
of the flushed color is completed under reduced pressure to
give 1816 parts of product. The viscosity of this product was
5742 poise as determined by a Laray viscometer and the tint
strength was 2 percent greater than the product of Example 6.
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It will be apparent to one of ordinary skill in the
art that many changes and modifications can be made to the
invention described herein without departing from the spirit
and scope thereof.
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