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United States Patent |
5,169,931
|
Sears
,   et al.
|
December 8, 1992
|
Nitrite-oxidized lignosulfonates and method of making the same and use
of these as dispersants
Abstract
A nitrite-oxidized base lignosulfonate and a method of making the same; the
method comprises providing a base lignosulfonate material and oxidizing it
in the presence of sodium nitrite under alkaline conditions at a
temperature greater than about 100.degree. C.; useful products of same are
dispersants for dyes and dispersants for setting materials e.g. gypsum.
Inventors:
|
Sears; Karl D. (Shelton, WA);
Byrd; Gerald J. (North Bend, WA)
|
Assignee:
|
ITT Rayonier Inc. (Stamford, CT)
|
Appl. No.:
|
704448 |
Filed:
|
May 23, 1991 |
Current U.S. Class: |
530/500; 530/501 |
Intern'l Class: |
C08H 005/02 |
Field of Search: |
530/500,501
|
References Cited
U.S. Patent Documents
1731433 | Oct., 1929 | Onnertz et al. | 530/500.
|
1829852 | Nov., 1931 | Darling | 162/81.
|
4488907 | Dec., 1984 | Sarkkinen | 530/500.
|
Other References
L. Primacheva, T. Adrianova, and V. Kirillova, Khim. Drev. (Riga), 1, 100
(1989). [Russ.].
L. Primacheva, T. Bugaeva, E. Gracheva, and N. Gladkova Gridroliz.
Lesokhim. Prom., 2, 15 (1986). [Russ.].
L. Primacheva, E. Gracheva, T. Bugazeva, and F. Pokhorukov, ibid., 3, 16
(1987). [Russ.].
L. Primacheva, E. Gracheva, N. Gladkova, T. Bugaeva, and F. Pokhorukov,
ibid., 7, 19 (1987). [Russ.].
L. Primacheva, T. Bugaeva, and V. Skachkov, ibid., 5, 11 (1988). [Russ.].
|
Primary Examiner: Kight, III; John
Assistant Examiner: Jones; Richard
Attorney, Agent or Firm: Keire; Fred A., Twomey; Thomas N.
Claims
What we claim is:
1. An elevated temperature nitrite-oxidized lignosulfonate wherein said
lignosulfonate is selected from at least one member of the group
consisting of ammonia base lignosulfonate, sodium base lignosulfonate,
calcium base lignosulfonate and magnesium base lignosulfonate, wherein
said oxidized lignosulfonate has a pH of above 7, a molecular weight
between about 6,000 Mw and about 100,000 Mw, and wherein said elevated
temperature oxidation is in an alkaline aqueous reaction medium between
100.degree. C. and about 200.degree. C. and at an autogenous pressure for
a temperature between 100.degree. and about 200.degree. C.
2. The nitrite oxidized lignosulfonate as defined in claim 1 wherein a
bound nitrogen content of said lignosulfonate is from above 0.0% to about
0.5% maximum on a weight basis.
3. The nitrite oxidized lignosulfonate as defined in claim 1 wherein said
nitrite oxidized lignosulfonate has 0.3% to 1.8% reduced amount of
organically bound sulfur, by weight, with respect to an unoxidized
starting material.
4. The nitrite oxidized lignosulfonate as defined in claim 1 wherein the
same is an ultrafiltered lignosulfonate and is a sodium base
lignosulfonate.
5. The nitrite oxidized lignosulfonate as defined in claim 4 wherein said
lignosulfonate is from coniferous wood species and is from spent sulfite
liquor.
6. The nitrite oxidized lignosulfonate as defined in claim 1 wherein the
lignosulfonate is an ammonia base lignosulfonate.
7. The nitrite oxidized lignosulfonate as defined in claim 1 wherein the
lignosulfonate is an ultrafiltered lignosulfonate.
8. The nitrite oxidized lignosulfonate as defined in claim 1 wherein a
sulfur content expressed as sulfur by weight in said nitrite oxidized
lignosulfonate is between about 3.5% to 6.6%, a sulfate content expressed
as sulfur between about 0.5% to 1.6% by weight, and organically bound
sulfur between about 2.5% and 5.1% by weight.
9. The nitrite oxidized lignosulfonate as defined in claim 1 wherein the
same is an ultrafiltered lignosulfonate prior to nitrite oxidation.
10. The nitrite oxidized lignosulfonate as defined in claim 1 wherein the
same is a nitrite-oxidized lignosulfonate prior to ultrafiltration.
11. The nitrite oxidized lignosulfonate as defined in claim 1 wherein the
same is in a solution from about 10% to about 70%, by weight, based on the
lignosulfonate material weight, on an oven dry basis, with reference to a
total solution weight.
12. The nitrite oxidized lignosulfonate as defined in claim 1 wherein the
same is in a solution in a concentration from about 25% to about 40%,
based on the lignosulfonate weight, on an oven dry basis, with reference
to a total solution weight.
13. A method for making an oxidized lignosulfonate derivative comprising
the steps of oxidizing a base-containing lignosulfonate material, said
material being selected from the group consisting of ammonia, sodium,
calcium, and magnesium base lignosulfonate material and mixtures thereof;
wherein said oxidizing is of said lignosulfonate material in an alkaline
aqueous reaction medium in the presence of a nitrite at a temperature
between about 150.degree. C. and about 170.degree. C. at a pressure of up
to about 150 psi (gage) including intermittently relieved pressure.
14. A method in accordance with claim 13 wherein the temperature is from
about 165.degree. C. to about 170.degree. C.
15. A method in accordance with claim 13 wherein the oxidizing is conducted
at pH from about 7 to about 14.
16. A method in accordance with claim 15 wherein the pH is from about 9 to
about 10 and the nitrite is sodium nitrite.
17. A method in accordance with claim 13 wherein sodium nitrite is
initially present in an amount from about 1.0 percent to about 20 percent,
by weight, based on the weight of lignosulfonate material on an oven dry
basis.
18. A method in accordance with claim 13 wherein sodium nitrite is
initially present in an amount of about 7.5 percent, by weight, based on
the weight of lignosulfonate material on an oven dry basis.
19. A method in accordance with claim 13 wherein the lignosulfonate
material is present in solution concentration from about 10 percent to
about 70 percent based on the lignosulfonate material weight, on an oven
dry basis, to total solution weight.
20. A method in accordance with claim 13 wherein the lignosulfonate
material is present in solution concentration from about 25 percent to
about 40 percent based on the lignosulfonate material weight, on an oven
dry basis, to total solution weight.
21. A method in accordance with claim 13 wherein the lignosulfonate
material is present in a concentration sufficient to provide a final
product viscosity of about 60 to about 100 centipoise at 20 degrees
Celsius.
22. A method in accordance with claim 13 wherein the method further
comprises ultrafiltering the material resulting from the nitrite oxidation
to remove low molecular compounds of molecular weight below about 6,000
Mw.
23. A method in accordance with claim 13 wherein the method further
comprises ultrafiltering the lignosulfonate material prior to the nitrite
oxidation to remove low molecular weight components of molecular weight
below 6,000 Mw.
24. A method in accordance with claim 13 wherein the nitrite oxidation is
conducted for a period of about 5 minutes to about 5 hours.
25. A method in accordance with claim 13 wherein the nitrite oxidation is
conducted for a period of about 45 minutes.
Description
FIELD OF THE INVENTION
The present invention relates to lignosulfonate derivatives and methods for
making these lignosulfonate derivatives and useful products thereof e.g.
dispersants.
BACKGROUND
Previously, reactions of lignin materials involving sodium nitrite have
related to its use at low temperatures in promoting diazo coupling
reactions and for introducing nitro groups. Such reactions have been
conducted under acidic conditions (in acid, sodium nitrite is converted to
nitrous acid). While nitrous acid has been used for nitration of lignin,
the prinicpal reagent used is nitric acid.
It has recently been found that one can avoid the degrading effects of
nitrating lignosulfonates with nitric acid by employing mixtures of sodium
nitrate and nitrite salts. These reactions are carried out in the
60.degree.-90.degree. C. range with a pH around 8.7-9.0. Under these
reaction conditions, nitro radicals are formed and react with the
lignosulfonates leading to organically bound nitrogen contents of 1.2-1.4%
in the reaction product.
DESCRIPTION OF THE VARIOUS EMBODIMENTS
The present invention contemplates the production of a lignosulfonate
derivative by the reaction of a base-containing lignosulfonate material
with sodium nitrite. The base-containing lignosulfonate is defined by its
methods of production, i.e., the pulping liquor used. The reaction
comprises oxidizing the lignosulfonate in the presence of sodium nitrite
under alkaline conditions. The resulting reaction product is an oxidized
lignosulfonate. This reaction is typically accompanied by desulfonation
and an increase in product viscosity, molecular weight and carboxyl
contents. The lignosulfonates employed in the reaction are normally
derived from coniferous wood species. The thus-produced lignosulfonate
derivatives or streams derived from them (e.g., by ultrafiltration) may be
used as e.g. gypsum dispersants or primary dye dispersants.
The reaction may be carried out with a variety of lignosulfonate starting
materials, such as
spent sulfite liquor,
chemically modified (e.g., desugared, desugared-sulfonated) spent sulfite
liquor,
fermented sulfite liquor
ultrafiltered material prepared from the preceding liquors and the like.
Ultrafiltered spent sulfite liquor or previously reacted reaction product
thereof are purified lignosulfonates from which low molecular weight
impurities have been removed by ultrafiltration. Ultrafiltration is used
advantageously for the separation of high molecular weight solutes from
their solvents--in this instance, lignosulfonates from wood sugars and
other solutes. The specified membrane will determine the material removed,
but typically materials of less than 6000 Mw (weight average molecular
weight) and up to 20,000 Mw (preferably) are removed. The retentate is
used in the process herein. However, it is possible to use specific
fractions in the molecular weight range up to 100,000 Mw if a product of
such characteristics is desired by employing appropriate membranes as it
is well known in the art. Therefore, specific fractions of the
lignosulfonate material can be used as desired. Suitable lignosulfonate
starting materials are base-containing lignosulfonates wherein the base is
selected from sodium, calcium, magnesium or ammonium, including, for
example, the following lignosulfonates:
ammonia-base sulfite pulping liquor of coniferous wood species found in the
Pacific Northwest,
sodium-base sulfite pulping liquor, e.g. the above named wood species,
calcium- or magnesium-base sulfite pulping liquor, preferably of the same
wood species.
Other sources of sulfite liquors of the above type that maybe useful are
bagasse, deciduous trees, mixtures of the foregoing, etc.
It has been found that while kraft black liquor and derived liquors have
been tried, these offer no advantages.
The present invention is particularly suitable to lignosulfonates from
spent sulfite pulping liquors, i.e., pulping liquors containing sulfur
dioxide, sulfurous acid and bisulfite, and especially those in which
calcium, sodium, magnesium and ammonia have been used as the source of the
base for making bisulfite. Kraft liquors are characterized by alkaline
pulping with sodium hydroxide and sodium sulfide as the major cooking
chemical. Preferred lignosulfonate starting materials are sodium-,
calcium-, magnesium-, and ammonia-base lignosulfonates. Of these, the
preferred species is the first.
Sodium-base lignosulfonate materials are commercially available from ITT
Rayonier, Stamford, Conn. as ULTRAMIX (an ultrafiltered, about 90% pure
lignosulfonate, derived from desugared-sulfonated spent sulfite liquor),
RAYMIX (a chemically desugared-sulfonated material derived from spent
sulfite liquor), and RAYLIG (an unmodified spent sulfite liquor material).
Calcium-base lignosulfonate material is also available from Georgia
Pacific Corporation as LIGNOSITE (fermented spent sulfite liquor).
Ammonia-base lignosulfonate material is available from ITT Rayonier as
ORZAN AL-50 1 (an unmodified spent sulfite liquor material).
While sodium nitrite is the preferred oxidizing agent in the reaction,
other nitrite salts (e.g., potassium) may also be used. Although the
reaction may be conducted to give useful products with a mixture of sodium
nitrite and sodium nitrate, it is preferred to use merely sodium nitrite.
The reaction of these lignosulfonate starting materials with sodium nitrite
is conducted at temperatures above about 100.degree. Celsius, desirably at
a reaction temperature greater than about 150.degree. C. and preferably at
temperatures from about 165.degree. C. to about 170.degree. C. and even
higher, e.g. up to 200.degree. C. Greater than atmospheric pressure is
used to achieve these temperatures since the reaction medium is an aqueous
system. The reaction is run at a basic pH (from above about 7 to about 14)
and preferably at a pH from about 9 to about 10. The reaction time is from
about 5 to about 600 minutes, with about forty-five (45) minutes being
preferred. Time to temperature, i.e., the time taken to reach the desired
reaction temperature, is from five (5) minutes to five (5) hours with
about twenty (20) to thirty (30) minutes being preferred.
Sodium nitrite is used in an amount from about 4.0 to 20.0% by weight of
lignosulfonate solids with about 7.5% by weight being preferred. The
lignosulfonate solids determinations are typically carried out by heating
about one (1) gram of lignosulfonate material for 16 hours at 105.degree.
C. or 90 minutes at 120.degree. C. to determine moisture loss.
Lignosulfonate material concentration may be from about 10% to about 70%
(preferably 25% to 40%) on a total solution weight basis. The starting
lignosulfonate solution solids concentration is preferably adjusted so
that after reaction with sodium nitrite the viscosity of the final product
at 20.degree. C. remains at about 100 centipoise (cps) or less (Brookfield
Viscometer, Model LVT, #2 spindle). As more nitrite is used in the
reaction, a reduced starting solution solids content should be used in
order to obtain a final product of acceptable viscosity within the above
range. The desired viscosity of the final product is from about 60 to
about 100 centipoise.
The nitrite oxidation of lignosulfonates has the potential to result in
desulfonation of organically bound sulfonate groups with the generation of
inorganic sulfate groups. In the nitrite oxidation of various sodium-base
lignosulfonates, a loss of about 0.3% to 1.8% of organically bound sulfur
may be observed; with calcium-base lignosulfonates about 1.2% to about
1.8%; and with ammonia-base lignosulfonates about 0.6% to about 0.9%. (See
Table 6.) The reaction achieves its desired oxidation results without
incorporating significant amounts of nitrogen into the lignosulfonate
materials. The increase in incorporated organically bound nitrogen in the
materials ranges from 0.0% to 0.5% maximum on a weight basis.
The products of the reaction of the present invention provide improved
dispersion benefits, particularly as gypsum dispersants and as primary dye
dispersants. A nitrite-oxidized ultrafiltered sodium-base lignosulfonate
prepared from ULTRAMIX (TM) provides particularly advantageous properties
as a primary dye dispersant, particularly with respect to milling
efficiency, foam build-up and fabric staining. With respect to gypsum
dispersion their performance is superior to the starting materials used in
their preparation such as ULTRAMIX or RAYMIX.RTM. from ITT Rayonier, and
their performance approaches that of the more expensive, high performance
naphthalene sulfonates, such as DILOFLO.RTM. GL sold by Henkel
Corporation. As a primary dye dispersant the nitrite oxidized
lignosulfonate prepared from ULTRAMIX is superior to kraft lignin derived
materials, such as REAX 85A (a lignosulfonate derived by sulfonating kraft
lignin) available from Westvaco, New York, N.Y.
In order to provide a ready overview of the materials used, their trade
names, and some of the nitrite oxidation products prepared from them and
described herein the following TABLE A is supplied:
TABLE A
__________________________________________________________________________
NITRITE-OXIDIZED BASE-CONTAINING LIGNOSULFONATES
(DERIVED FROM SPENT SULFILTE LIQUOR)
Trade Name Fermented
Sulfonated
Desugared
of Starting Material and
Ultrafiltered (after
Ultrafiltered
(before
(before
(before
Base
Product Prepared
oxidation)
(before oxidation)
oxidation)
oxidation)
oxidation)
NH.sub.4
Na
Ca
__________________________________________________________________________
ORZAN AL-50 -- -- -- -- -- --
--
LOT 3D, Ex. 3
-- -- -- -- --
--
LIGNOSITE -- -- -- -- -- --
Lot 2B, Ex. 2
-- -- -- -- -- --
RAYLIG -- -- -- -- -- -- --
Lot 5B, Ex. 5
-- -- -- -- -- --
RAYMIX -- -- -- -- --
Lot 6B, Ex. 6
-- -- -- --
ULTRAMIX -- -- -- --
Lot 1A, Ex. 1
-- -- -- --
__________________________________________________________________________
If desired, the reaction product may further be ultrafiltered. This is
particularly advantageous in obtaining high quality gypsum dispersants
from nitrite oxidized spent sulfite liquor prepared, for example, from
ORZAN AL-50.
A series of experiments were conducted by reacting sodium nitrite with
1. sodium-base lignosulfonates (the ULTRAMIX product from ITT Rayonier)
(Example 1A-C);
2. calcium-base lignosulfonates (the LIGNOSITE product from Georgia
Pacific) (Example 2);
3. ammonia-base lignosulfonates (the ORZAN AL-50 product from ITT Rayonier)
(Example 3) and
4. kraft lignin (the REAX 85A product from Westvaco) (Example 4),
Examples 1 through 3 are in accordance with the present invention. The
reaction products were evaluated in comparative dispersion tests (Table
5).
Primary dye dispersion tests are presented for nitrite oxidized ULTRAMIX
further described herein.
Several reactions with calcium-base lignosulfonates were carried out using
different starting amounts of solution solids.
Reactions with ammonia base lignosulfonates were carried out using
different starting amounts of solution solids to find the optimum level
with regard to final product viscosity.
One of the reaction products (Lot 3A) was also ultrafiltered and the
retentate tested for its dispersant utility.
Analytical data relating to levels of desulfonation experienced as a result
of nitrite oxidation of various base containing lignosulfonates are in
Table 6.
The following examples are intended to illustrate the invention but not to
limit its scope.
EXAMPLE 1
Reaction of Sodium Base Lignosulfonates ULTRAMIX with Sodium Nitrite
A. Preparation of Lot 1A
ULTRAMIX solution (2763 g: percent total solids was 30.43 or 870 g of
solids--oven dry basis) was diluted to 3000 g with water. This yielded a
solution that was 29.0% total solids. To this solution while stirring was
added 65.25 g of sodium nitrite (99% purity). This amount represents 7.5%
of sodium nitrite based on Ultramix starting solids. The pH was then
adjusted to pH 10.0 with 50% caustic (sodium hydroxide). The mixture was
transferred to a small autoclave vessel (4 liter). While stirring, the
autoclave contents were heated to 165.degree. C. (20 minutes to
temperature) and then maintained at about 165.degree. C. for 45 minutes.
The reaction was ended by running cold water through the autoclave jacket.
The contents were removed from the autoclave. The viscosity (at 20.degree.
C.), pH, and oven dry solids were obtained. Results appear in Table 1.
B. Lot 1B
The reaction was conducted in a similar manner as for Lot 1A, except the
ULTRAMIX solution solids after dilution to 3000 g was 34.0% (1020 g of
solids). The amount of sodium nitrite added was 1.0% based on Ultramix
solids, or 10.2 grams. Results appear in Table 1.
C. Lot 1C
The reaction was conducted in a similar manner as for Lot 1A, except the
ULTRAMIX solution solids, after dilution to 3000 g, was 26.0% (780 g of
solids). The amount of sodium nitrite added was 20.0% based on ULTRAMIX
solids, or 156 grams. Results appear in Table 1.
The reaction parameters for these experiments are tabulated as follows in
Table 1:
TABLE 1
______________________________________
Reaction of Sodium-Base Lignosulfonate, ULTRAMIX with
Sodium Nitrite
Starting
Material Reaction Product
Product
% Sodium Solids.sup.2,
Solids, Viscosity.sup.3,
No. Nitrite.sup.1
% pH % pH cps
______________________________________
Lot 1A 7.5 29.0 10.0 29.9 9.4 80
Lot 1B 1.0 34.0 10.0 34.1 9.2 85
Lot 1C 20.0 26.0 10.0 28.7 9.4 555
______________________________________
.sup.1 Amount added in % based on weight of lignosulfonate solids.
.sup.2 Starting content of lignosulfonate solids in solution (weight
basis) before addition of solid NaNO.sub.2 and 50% NaOH.
.sup.3 Viscosity of final reaction product at 20.degree. C. using a
Brookfield Viscometer (Model LVT, #2 Spindle).
In the reaction of ULTRAMIX lignosulfonate with sodium nitrite (the last
available from BASF) using 20% sodium nitrite by weight of ULTRAMAX solids
(Lot 1C), the starting solution solids selected was 26%. While it has been
observed that increasing nitrite levels lead to products of increased
viscosity, it was believed that this would be a satisfactory level to
attain a target viscosity of from 60 to 100 centipoise. This was not
enough of a reduction since final product viscosity was around 500 cps
(Table 1). The resulting nitrite-oxidized lignosulfonate was, however, a
very good performing product based on gypsum dispersion performance (Table
5). Reducing starting material solids content even more would further
reduce product viscosity. It is desirable to have the solution viscosity
after preparation at 100 cps (at 20.degree. C.) or less since the liquid
product gradually increases in viscosity with time. Levels higher than 100
cps (at 20.degree. C.) reduce the products useful shelf life below
practical limits.
While the product prepared using 1.0% sodium nitrite had an acceptable
viscosity profile (Table 1), it was a poor gypsum dispersant compared to
the 7.5% product (Lot 1A), and considerably poorer than Diloflo GL (Henkel
Corporation) the comparison material (Table 5) of commercial choice.
The most desirable product in this series (Table 1) with regard to gypsum
dispersant performance and viscosity properties is Lot 1A.
EXAMPLE 2
Reaction of Calcium-Base Lignosulfonates with Sodium Nitrite: Lots 2A and
2B (Table 2)
A. Preparation of Lot 2B
LIGNOSITE lignosulfonate [1496 g; percent total solids was 50.19 or 750.8 g
O.D. (oven dry solids basis)] was diluted with water to bring the solution
to 2,086 grams. This yielded a solution that was 36% total solids. Sodium
hydroxide solution (50%) was added to bring the pH above 7 and 56.3 g of
sodium nitrite of 99% purity (available from BASF) was added with
stirring. This amount represents 7.5% of sodium nitrite based on LIGNOSITE
solids. The pH was then adjusted to 10.0 with 50% sodium hydroxide. The
material was transferred to a small autoclave (4 liter). The autoclave
contents were heated with stirring to 165.degree. C. (25 to 30 minutes
elapsed in reaching that temperature) and maintained there for 45 minutes.
Maximum pressure reached in this reaction was about 95 pounds per square
inch gauge. The reaction was ended by running cold water through the
autoclave jacket. Then the contents were removed from the autoclave. The
viscosity at 20.degree. C. was 120 cps, the pH was 8.02 and the percent
total solids was 36.10.
In the first reaction of sodium nitrite with LIGNOSITE lignosulfonate (Lot
2A), the starting solids content of the LIGNOSITE was 34.0% on a weight to
volume basis. This resulted in a lower viscosity product at 20.degree. C.
than desired (35 cps actual compared to about 60-100 cps desired.)
However, there were definite improvements in gypsum dispersant performance
compared to unreacted LIGNOSITE itself (particularly at the 0.2% dosage
rate level where dispersion efficiency increased to 86% that of the
DILOFLO GL naphthalene sulfonate compared to only 49% for unreacted
LIGNOSITE itself.)
Increasing the starting solids content to 36.0% (Lot 2B) led to a reaction
product with viscosity nearer that desired (120 centipoise actual). This
product had better performance at the 0.1% level in gypsum dispersion
tests (see Table 5), but still not as good as nitrite oxidized ULTRAMIX
(e.g. Lot 1A, Tables 1 and 5). It was observed that the gypsum set
retardation, as measured by set time, of Lot 2B exceeded that of both
unreacted LIGNOSITE and Lot 2A (which was prepared at a lower starting
solids level). The reaction parameters for those experiments were as shown
in Table 2 below:
TABLE 2
______________________________________
Reaction of Calcium-Base Lignosulfonate with 7.5% Sodium
Nitrite
Starting Material
Reaction Product
Solids.sup.1, Solids, Viscosity.sup.2,
Product No.
% pH % pH cps
______________________________________
Lot 2A 34.0 10.0 34.1 7.3 35
Lot 2B 36.0 10.1 36.1 8.0 120
______________________________________
.sup.1 Starting content of lignosulfonate solids in solution before
addition of solid NaNO.sub.2 and 50% NaOH.
.sup.2 Viscosity of final reaction product at 20.degree. C., taken within
4 hours after reaction using a Brookfield Viscometer (Model LVT, #2
Spindle).
EXAMPLE 3
Reaction of Ammonia-Base Lignosulfonates with Sodium Nitrite: Lots 3A. 3B
and 3C
Concentrated ammonia base spent sulfite liquor (ORZAN AL-50) lignosulfonate
from ITT Rayonier (Stamford, Conn.) of 1818 g; and a total amount of
51.15% total solids, (or 930 g of solids on an oven dry basis) was diluted
with water to bring the solution weight to 3000 g, producing a solution
solids content of 31%. A sodium hydroxide solution (50%) was added to
bring the pH above 7, and then sodium nitrite was added (69.75 g, or 7.5%
based on lignosulfonate solids.) The pH was then adjusted to 9.0 with 50%
sodium hydroxide solution. The solution was transferred to a small
autoclave where it was heated at 165.degree.-168.degree. C. for 45
minutes. (Time to reach that temperature was about 20 minutes.) Whenever
the pressure of the autoclave reached about 130 pounds per square inch
(gauge), it was relieved down to 100 pounds per square inch; this occurred
about 4 times. The final reaction product had: viscosity at 20.degree. C.
of 148 centipoise, a pH of 4.3 and % total solids of 30.1. The reaction
parameters were as listed in Table 3:
TABLE 3
______________________________________
Reaction of Ammonia-Base Lignosulfonate with 7.5%
Sodium Nitrite
Starting Material
Reaction Product
Solids.sup.1, Solids, Viscosity.sup.2,
Product No.
% pH % pH cps
______________________________________
Lot 3A 35.0 9.0 34.0 4.3 3650
Lot 3B 30.0 9.0 29.2 4.3 58
Lot 3C 31.0 9.0 30.1 4.3 148
______________________________________
.sup.1 Starting content of lignosulfonate solids in solution before
addition of solid NaNO.sub.2 and 50% NaOH.
.sup.2 Viscosity of final reaction product at 20.degree. C. taken within
hours after reaction, using a Brookfield Viscometer (Model LVT, #2 and #3
spindles).
Lot 3C product was nearer the desired 100 centipoise viscosity level. (It
is believed that about 30.5% starting solids would put one at the desired
100 centipoise level at 20.degree. C.) In gypsum dispersion testing this
material did very well compared to the ammonia base lignosulfonate
starting material itself, and reasonably well compared to DILOFLO GL
naphthalene sulfonate (see Table 5). The gypsum set retardation, as
measured by set time, was also quite low relative to ORZAN CG sodium
lignosulfonate (Table 5).
TABLE 3A
______________________________________
Ultrafiltration.sup.1 of Nitrite-Oxidized
Ammonia-Base Lignosulfonate
Ultrafiltered
Feed Solids,
Concentration
Retentate
Product No.
% Ratio.sup.2 Recovery, %
______________________________________
Lot 3D 8.05 4.5 62.1
______________________________________
.sup.1 At 60.degree. C.
.sup.2 Starting volume divided by retentate volume.
The ultrafiltration of Lot 3C to obtain Lot 3D was carried out on a DDS (De
Danske Sukkerfabrikker--The Danish Sugar Corporation) Lab 20 unit at
60.degree. C. using GR-61PP membranes (polysulfone membranes with a 20,000
molecular weight cutoff--manufactured by and available from DDS). Lot 3C
(800 g of solids) was first pH adjusted to 9.0 with 50% sodium hydroxide
and then the starting solution feed solids were adjusted to 8.05%.
Pressures during ultrafiltration were: 5.5-6.0 bars inlet, 4.0-4.5 bars
outlet. After ultrafiltering to a 4.5 concentration ratio (starting volume
divided by retentate volume), the retentate fraction (Lot 3D) contained
497 g of total solids (62.1% of the starting solids); the permeate
fraction contained 276 g of total solids (34.5% of the starting solids).
The amount of starting solids lost during the ultrafiltration was only
3.4% or about 27 g.
The results show that at least 62% of the starting material solids were
retained after ultrafiltration, and that it performed very well relative
to the DILOFLO GL naphthalene sulfonate in gypsum dispersion tests (see
Table 5). In fact, it appeared to actually outperform the DILOFLO GL
product at the 0.1% level. The gypsum set retardation was far less for the
material after ultrafiltration than before. It appears that this material
also outperforms nitrite oxidized ULTRAMIX (Lot 1A) from Example 1 above,
in both gypsum dispersion and set retardation.
Nitrite oxidation of sodium base spent sulfite liquor (RAYLIG) under a set
of desirable conditions (39.0% starting solids and pH of 10.0 using 7.5%
sodium nitrite) yields material which when ultrafiltered to a
concentration ratio of 5.0 gives a retentate product that also performs
very well in gypsum tests relative to DILFLO GL. However, the performance
does not equal that obtained from Lot 3D (ultrafiltered, nitrite oxidized
ammonia base spent sulfite liquor as described above).
In all the nitrite oxidation reactions with ammonia base lignosulfonates
the starting pH was adjusted to 9.0 rather than 10 (which, generally, is
the desired starting pH for lignosulfonate starting materials). This
change was made to reduce the generation of ammonia vapors. As a result of
this lower starting pH, the final product pH was lower than that for other
nitrite-oxidized lignosulfonate products prepared in accordance with the
present invention. The reaction product was on the acid side (pH of 4.3,
Table 3).
EXAMPLE 4
Reaction of Kraft Lignin with Sodium Nitrite: Lot 4A
Kraft lignin (such as REAX 85A kraft lignin from Westvaco) in an amount of
1683 grams of a 32.11% total solids content or 540.4 grams (oven dry) was
diluted to 2078.5 grams of total weight with water (a solution solids
content of 26.0%) (Lot 4A, Table 6.) To this solution, of pH 8.2, was
added sodium nitrite (40.53 grams or 7.5% of sodium nitrite based on REAX
85A solids.) Sodium hydroxide solution (50%) was added to bring the pH to
10.0. The solution was transferred to the previously described autoclave
and heated to 165.degree. C. (50 minutes to reach this temperature) and
maintained there for 45 minutes. The maximum pressure attained during
reaction was 100 pounds per square inch (gauge). Final product properties
were: pH of 9.4, viscosity at 20.degree. C. of 90 Cps and % total solids
of 26.82. Reaction parameters are summarized as follows in Table 4:
TABLE 4
______________________________________
Reaction of Kraft Lignin, REAX 85A with 7.5% Sodium Nitrite
Starting Material
Reaction Product
Solids.sup.1, Solids, Viscosity.sup.2,
Product No.
% pH % pH cps
______________________________________
Lot 4A 26.00 10.0 26.8 9.4 940
______________________________________
.sup.1 Starting content of lignosulfonate solids in solution before
addition of solid NaNO.sub.2 and 50% NaOH.
.sup.2 Viscosity of final reaction product at 20.degree. C., taken within
4 hours after reaction, using a Brookfield Viscometer (Model LVT, #3
spindle).
It was of interest to see if nitrite oxidation of a kraft lignin derived
material would lead to any improvements in gypsum dispersion performance
as had been observed with sodium-, calcium-, and ammonia-base
lignosulfonate materials. It was observed that its level of reactivity was
very low since it took a much longer time to heat up to temperature
compared to sodium-, calcium-, and ammonia-base lignosulfonates (e.g., 45
minutes compared to 20 for sodium base lignosulfonates).
While the viscosity was observed to increase during the reaction, no
improvement in gypsum dispersion performance was observed (see Table 5.)
The level of dispersion actually decreased at the 0.2% dosage rate level.
It is noteworthy that the dispersion performance of the unreacted REAX 85A
kraft lignin starting material itself is good compared to DILOFLO GL
napthalene sulfonate; however it has very poor gypsum set retardation
characteristics compared to accepted commercial products for this
application (e.g. ORZAN CG by ITT Rayonier).
Nitrite oxidations of kraft black liquor itself that were carried out
showed no beneficial performance effects whatsoever in gypsum dispersion
tests. In fact results were the same for reacted and unreacted materials.
Gypsum Dispersion Testing
The gypsum dispersant product and set retardation tests were run using
techniques paralleling appropriate ASTM procedures.
In gypsum dispersion tests, water-gypsum mixtures are made with and without
added dispersants, but with a constant amount of water, and poured out
onto a glass plate. The increase in the size of the resulting patty
containing the dispersant, over that without, is a measure of the
efficiency of the dispersant.
In these tests, the standard amount of gypsum stucco (CaSO.sub.4.1/2H.sub.2
O--calcium sulfate hemihydrate--supplied by Domtar, Long Beach, Cal.;
combined water content, 5.4-6.0%; particle size, 5.4-5.9 microns) used is
50 g; the amount of dispersant used in the tests, typically, is 0.1 and
0.2% of product solids based on stucco weight, or 0.050 and 0.100 g,
respectively.
The efficiency of the dispersant product tested is calculated by dividing
the average diameter of two patties made with dispersant by the average
diameter of the two patties without, multiplying by 100, and subtracting
100 to give a percentage. For example, if the control patties (i.e., no
dispersant added) have an average diameter of 87 millimeters and the
patties made with dispersant average 104 millimeters, the efficiency for
the dispersant is: (104/87.times.100)-100=20%.
In the following Table (5), the dispersion efficiency of each product is
compared to that of DILOFLO GL (Henkel Corporation--a high performance
naphthalene sulfonate sold as a gypsum dispersant for gypsum board
manufacture). The dispersion effiencies reported in "% compared to DILOFLO
GL" are obtained by dividing the dispersion efficiency of the product
tested by the dispersion efficiency determined for DILOFLO GL, and then
multiplying by 100. Dispersion efficiences for DILOFLO GL were measured on
the same date each product listed in Table 5 was tested.
For example, if the dispersion efficiency of a product at 0.1% dosage rate
is 22%, and that of DILOFLO GL is 25%, "Dispersion Efficiency, % Compared
to DILOFLO GL" is: 22/25.times.100=88.
The set retardation test is a modified Vicat method (similar to ASTM C
472-68-9,10) in which 50 grams of stucco is added to an appropriate amount
of water or water-dispersant mixture in a foam cup. Timing is started with
addition. After mixing vigorously, the mixture is allowed to sit until
judged to be at the time of initial set. The Vicat apparatus consists of a
one millimeter diameter needle backed by a 300 g weight, all supported by
a frame. The needle is lowered until it just touches the surface of the
slurry, then allowed to drop. Until initial hydration has occurred, the
needle will go clear to the bottom of the cup. The point where the slurry
begins to support it above the bottom of the cup is considered to be the
set time. The time is recorded. Tests are conducted in duplicate. The set
times were carried out using 0.2% of product solids based on stucco, or
0.100 g.
The set times in Table 5 are recorded as the "% above control". These
values are obtained by dividing the set time for the stucco with
dispersant by the set time of the stucco without dispersant (i.e., the
control), multiplying by 100, and then subtracting 100.
For example, if the stucco with dispersant sets in 1500 seconds, and the
stucco without dispersant (i.e., the control) sets at 1000 seconds, the
set time, expressed as "% above control" is: (1400/1000.times.100)-100=40.
Set time results are affected by ambient moisture and temperature levels,
so values can vary substantially from one day to the next; however,
results relative to a standard run each time tend to be similar. That is
why ORZAN CG, a sodium lignosulfonate gypsum dispersant sold by ITT
Rayonier, was run as a set retardation standard whenever set times were
determined on the product whose test results are recorded in Table 5.
TABLE 5
______________________________________
Comparative Gypsum Test Results
Dispersion
Efficiency, %
Compared to
DILOFLO GL.sup.1
Dosage Rate.sup.2
SET TIME (%
Product No. 0.1% 0.2% above control.sup.3)
______________________________________
Sodium Base Lignosulfonate, ULTRAMIX/Sodium Nitrite
Reaction Products
1 Starting Material
68 67 --
(ULTRAMIX
lignosulfonate)
2 Lot 1A 92 92 19
3 Lot 1B 83 -- --
4 Lot 1C 108 97 --
5 Orzan CG -- -- 30
lignosulfonate.sup.4
Calcium Base Lignosulfonate, LIGNOSITE/Sodium Nitrite
Reaction Products
6 Starting Material
60 49 36
LIGNOSITE
lignosulfonate
7 Lot 2A 68 86 36
8 Lot 2B 76 86 43
9 ORZAN CG 48
lignosulfonate.sup.4, 5
Ammonia Base Lignosulfonate, ORZAN AL-50/Sodium Nitrite
Reaction Product
10 Starting Material
46 56 14 --
(ORZAN AL-50
lignosulfonate)
11 Lot 3A 73 86 19 --
12 Lot 3B 58 83 17 --
13 Lot 3C 78 89 -- 5
14 ORZAN CG -- -- 39 34
lignosulfonate.sup.4
Ultrafiltered Ammonia Base Lignosulfonate, ORZAN AL-50/
Sodium Nitrite Reaction Products
15 Lot 3C (feed) 78 89 13
16 Lot 3D 104 97 8
17 ORZAN CG 34
lignosulfonate.sup.4
Kraft Lignin, REAX 85A/Sodium Nitrite Reaction Products
18 Starting Material
88 94 75
(REAX 85A Kraft
lignin Example 4)
19 Lot 4A 88 78 65
20 Orzan CG -- -- 39
lignosulfonate.sup.4
Sodium Base Lignosulfonate, RAYLIG/Sodium Nitrite
Reaction Product (Example 5, below)
21 Starting Material
42 52 --
(RAYLIG
lignosulfonate)
22 Lot 5A-2.sup.6 60 78 --
Ultrafiltered Sodium Base Lignosulfonate, RAYLIG/Sodium
Nitrite Reaction Product
23 Lot 5B 97 89 19
24 Orzan CG -- -- 41
Lignosulfonate.sup.4
Sodium Base Lignosulfonate, RAYMIX/Sodium Nitrite
Reaction Product (Example 6, below)
25 Starting material
63 66 --
(Raymix
lignosulfonate)
26 Lot 6A 100 88 47
27 Orzan CG.sup.4 -- -- 40
Ultrafiltered Sodium Base Lignosulfonate, RAYMIX/Sodium
Nitrite Reaction Product (Example 6, below)
28 Lot 6B 104 107 26
______________________________________
.sup.1 A naphthalene sulfonate sold by Henkel Corp. as a high performance
dispersant for gypsum board manufacture.
.sup.2 Percent product solids on stucco.
.sup.3 Carried out at a dosage rate of 0.2% product solids based on
stucco. The control is the set time of stucco with no dispersant present.
.sup.4 A sodium lignosulfonate gypsum dispersant sold by ITT Rayonier and
used as a set retardation standard for this study.
.sup.5 These values obtained on a different test date from the others in
this section (causing change in properties).
.sup.6 Prepared in a manner similar to Lot 5A, Example 5.
EXAMPLE 5
Reaction of Sodium Base Lignosulfonate, RAYLIG, with Sodium Nitrite
Lot 5A:
Concentrated sodium base spent sulfite liquor (RAYLIG, 2265 g; 51.7% total
solids, or 1,170 g of solids on an oven dry basis) was diluted with water
to bring the solution weight to 3000 g, producing a solution solids
content of 39.0%. A sodium hydroxide solution (50%) was added to bring the
pH above 7, and then sodium nitrite was added (87.75 g, or 7.5% based on
lignosulfonate solids). The pH was then adjusted to 10.0 with 50% sodium
hydroxide solution, and the solution transferred to the small autoclave
where it was heated at 165.degree. C. for 45 minutes (time to
temperature=20 minutes). This was a vigorous reaction in the early stages
and pressure was released several times to keep the pressure below 150
psi. The final reaction product had a viscosity of 102 cps at 20.degree.
C., a pH of 5.7 and a percent total solids content of 36.9.
Product prepared in the above manner performed much better in gypsum
dispersant tests than the starting material (RAYLIG; see Table 5). The
performance at the 0.2% level was notably better (78% dispersion
efficiency relative to DILOFLO GL, compared to 52% for unreacted RAYLIG).
If product prepared in this manner is ultrafiltered at 60.degree. C. using
a polysulfone membrane GR-61PP (described above) to a concentration ratio
of 4.75 (feed solids of 9.0% with pH of 9.0), a retentate product is
recovered that performs very well compared to DILOFLO GL. A product
prepared in this way, Lot 5B, had a dispersion efficiency relative to
DILOFLO GL of 97% (see Table 5) at the 0.1% dosage rate; the set
retardation of this product was quite low compared to set retardation of
the Orzan CG standard (at least 50% less retarding at the 0.2% dosage rate
used in the test).
EXAMPLE 6
Reaction of Sodium Base Lignosulfonate, RAYMIX, with Sodium Nitrite
Lot 6A
A solution of RAYMIX lignosulfonate (2273 g; 46.2% total solids, or 1050 g
of solids) was diluted with water to bring the solution weight to 3000 g.
This yields a solution that is 35% in total solids content. To this
material was added, with stirring, sodium nitrite (78.75 g, or 7.5% based
on lignosulfonate solids). The pH was then adjusted to 10.0 with 50%
sodium hydroxide solution, and the solution transferred to the small
autoclave where it was heated to 165.degree. C. (20 minutes to
temperature) and maintained there for 45 minutes. Maximum pressure reached
during the reaction was about 120 psi. The final reaction product had a
viscosity at 20.degree. C. of 87.5 centipoise, pH 8.8, and a total solids
of 34.7%.
Product prepared in this manner had excellent gypsum dispersion properties.
At the 0.1% dosage level, the material had a gypsum dispersion efficiency
that showed it to be equal to DILOFLO GL (see Table 5). This was far
better than unreacted RAYMIX lignosulfonate itself, and also better than
any nitrite oxidized non-ultrafiltered lignosulfonate product prepared as
described herein. The set retardation properties are poor when compared to
all of the other products. The retardation properties as determined by set
time were higher than for ORZAN CG itself (47% compared to 40% for ORZAN
CG).
Ultrafiltering the material to a 4.8 concentration ratio at 60.degree. C.
on the GR-61PP a membrane as described in Example 5 (feed solids content
of 9.9% with pH of 9.0; retentate recovery of 48.1%) gave material (Lot
6B) with better gypsum dispersion properties than DILOFLO GL at both
dosage levels tested. The retardation properties were definitely better
than for the non-ultrafiltered product--reduced to about 65% that of Orzan
CG at the 0.2% dosage level employed in this test (see Table 5).
In order to determine the extent of desulfonation experienced in the
nitrite-oxidation reactions discussed here, appropriate sulfur analyses
were carried out and these results appear in the following Table 6:
TABLE 6
______________________________________
SULFUR ANALYSIS
Org.
Sulfate Bound
Sulfur (as Sulfur)
Sulfur
Product No. % % %
______________________________________
Sodium Base Lignosulfonate, ULTRAMIX/Nitrite Reaction
Products
ULTRAMIX (unreacted)
6.92 0.47 6.45
Lot 1A-2 6.41 1.38 5.03
Calcium Base Lignosulfonate, LIGNOSITE/Nitrite Reaction
Products
LIGNOSITE (unreacted)
6.75 0.50 6.25
Lot 2A 5.97 0.92 5.02
Lot 2B 5.44 0.99 4.45
Ammonia Base Lignosulfonate, ORZAN AL-50/Nitrite Reaction
Products
ORZAN-AL-50 (unreacted)
5.42 0.65 4.77
Lot 3A 5.18 1.21 3.97
Lot 3B 5.42 0.95 3.87
Lot 3C 5.45 1.30 4.15
Kraft Lignin, REAX 85A/Nitrite Reaction Products
REAX 85A (unreacted)
3.67 0.77 2.90
Lot 4A 3.66 0.93 2.73
Sodium Base Lignosulfonate, RAYLIG/Nitrite Reaction Product
RAYLIG (unreacted)
5.36 0.57 4.79
Lot 5A-3 5.42 0.90 4.52
Sodium Base Lignosulfonate, RAYMIX/Nitrite Reaction Product
RAYMIX (unreacted)
7.57 0.50 7.07
Lot 7A 7.39 1.59 5.80
______________________________________
.sup.1 Prepared in a manner analogous to Lot 1A, Example 1A.
.sup.2 Prepared in a manner analogous to Lot 5A, Example 5.
In the reactions with LIGNOSITE calcium-base lignosulfonate, a maximum of
about 1.8% of organically bound sulfur was lost under the most optimum
conditions employed (Lot 2B, Table 6). With ULTRAMIX, the level of
organically bound sulfur lost under optimum conditions was about 1.4%. In
the reactions with ammonia base lignosulfonates losses up to 0.5-0.9% of
organically bound sulfur occurred. (It is believed that the amount would
have been more is a more purified ammonia-base lignosulfonate material had
been used since LIGNOSITE and ULTRAMIX lignosulfonates, for example, are
about 80 and 90%, respectively, in lignosulfonate contents.
It is event from Table 6 that the amount of desulfonation occurring in
kraft lignin (REAX 85A) upon reaction with nitrite is very low (only
0.17%). This is far lower from that which occurs with any of base
lignosulfonate reaction products and is indicative of the low reactivity
of this material with respect to nitrite oxidation. This tends to support
the experimental findings that kraft liquor materials are not particularly
useful as resources for nitrite oxidation compared to base lignosulfonate
materials.
The following Table 7 (A and B) is intended to illustrate the effect on the
lignosulfonate ULTRAMIX reacted with varying amounts of sodium nitrite at
the reaction conditions. Table 8 which follows illustrates the effect of
reacting kraft black liquor itself with sodium nitrite.
TABLE 7
__________________________________________________________________________
Reaction of Ultramix at Varying Sodium Nitrite, and Starting Solids
Levels.sup.a
ULTRAMIX REACTION PRODUCT
Sodium
Starting Visc. GYPSUM DISPERSION
Nitrite,.sup.b
Solids,.sup.c
Starting
20.degree. C.,
Solids,
% ABOVE CONTROL
Lot No. % % pH.sup.c
cps pH % 0.1%.sup.d
(Eff.).sup.e
__________________________________________________________________________
7A
7A 7.5 29.0 10.0 86 9.4
29.9 24.4 (99)
1B 1.0 34.0 10.0 85 9.2
34.1 20.6 (83)
7B 2.0 29.0 10.0 22 9.2
29.2 20.6 (83)
7C 2.0 32.0 10.0 75 9.2
32.4 20.9 (85)
7D 1.0 29.0 10.0 20 9.1
29.2 19.5 (79)
7E 0.0 29.0 8.8 17 8.8
29.4 17.6 (71)
DILOFLO GL
-- -- -- -- -- -- 24.7 --
7B
7F 5.0 32.0 10.0 348 9.4
32.3 21.4 (94.3)
7A 7.5 29.0 10.0 86 9.4
29.9 21.4 (94.3)
DILOFLO GL 22.7
__________________________________________________________________________
.sup.a Reactions carried out at 165-167.degree. C. for 45 minutes (about
20 minutes to temperature).
.sup.b Amount added based on weight of Ultramix solids.
.sup.c Starting solids of Ultramix solution before addition of solid
NaNO.sub.2, and 50% NaOH to adjust pH to starting pH level shown.
.sup.d Dosage rate, % product solids on stucco.
.sup.e % Efficiency compared to Diloflo GL (see previous definitions).
TABLE 8
__________________________________________________________________________
Reaction of Kraft Black Liquor with Sodium Nitrite
at Varying Starting Solids Levels.sup.a
Kraft Black Liquor
Reaction Product
Gypsum Dispersion
Starting
Visc.
Visc. % Above
Solids, 20.degree. C.,
20.degree. C.,
Solids,
Control at
Lot No.
%.sup.b
pH cps cps pH % 0.1%.sup.c
__________________________________________________________________________
8A 35.0 13.5
-- 17.5
13.5
37.4
6.7
8B 42.0 13.5
50 45 13.5
43.7
6.4
8C 48.7 13.6
248 235 13.7
50.0
6.7
8D 48.7 13.6
-- -- -- -- 6.4
__________________________________________________________________________
.sup.a 7.5% NaNO.sub.2 added based on kraft black liquor solids. Reaction
temperature 165-167.degree. C. for 45 minutes (20-25 minutes to
temperature).
.sup.b Starting solids of kraft black liquor before addition of solid
NaNO.sub.2.
.sup.c Dosage rate, % product solids on stucco.
From the above Tables 7 (A and B) it is seen that nitrite oxidized sodium
lignosulfonates are very cost effective dispersants for gypsum and like
dispersions. Such dispersants are obtained only upon proper nitrite
oxidation where the amount of sodium nitrite used is about 4.5% desirably
5.0%, and above based on lignosulfonate solids (at lower sodium nitrite
reactant level higher amounts of solids are needed to achieve
approximately the same dispersion efficiency). About 7.5% of sodium
nitrite used indicates a preferred usage level. Although higher amounts
may be used e.g. up to 10% and even 20% (Cf. Lot 1C--Example 1)--these
amounts are not cost effective for such bulk material as lignosulfonates
and also increase the viscosity. It is noted that, if the viscosity of the
products (Lot 7F, Table 7-B) is allowed to increase such as over prolonged
period of standing, then the product may not be as desirable. Hence, the
viscosities are preferred to be below 100 cps (as defined herein) although
higher ranges are useful as shown in Table 7-B. In the absence of any
sodium nitrite the dispersion efficiency is markedly lower. The dispersion
standard used has been the previous standard DILOFLO GL described above.
When comparing Tables 7 and 8 it is seen that sodium nitrite treatment of
kraft black liquor does not seem to indicate any satisfactory results.
When kraft black liquor is treated and used as a dispersant for gypsum, no
benefit seems to result from such treatment of kraft process based
liquors.
As another aspect of the invention, a product corresponding to Lot 1A was
also evaluated as a dye dispersant for commercially available dyes--both
disperse dyes and vat dyes--and as a replacement for commercially
available lignins used for that purpose.
Disperse dyes are non-soluble azo or anthraquinone based dyes applied to
the fiber material as a dispersion. Vat dyes are mostly anthraquinone dyes
applied as a solution. These dyes are well know and are typically referred
to by the Color Index number for these (C.I. No.).
PRIMARY DYE DISPERSANT TESTING
Products prepared as a result of this nitrite oxidation technology, offer
superior potential as a primary dye dispersants. As a candidate product, a
nitrite oxidized ULRAMIX product prepared under optimum conditions
(Example 1A) was selected. Simple screening tests such as fabric staining
and azo dye reduction tests (but not actual dye dispersion tests
themselves) established the 1A product to be the most likely candidate. It
was subjected to comprehensive testing as a primary dye dispersant
utilizing the tests described below. It is noted that the example
illustration is intended to show the potential for all suitable novel
products.
It was compared alongside REAX 85A (Westvaco Corporation of Example 4), a
widely used industry standard for disperse dyes, and against Marasperse
CBSO-4 (available from Daishowa-Reed Company, Greenwich, Conn.), an
industry standard for vat dyes. The specific product evaluated was Lot
1A-3, prepared in a manner similar to that used to prepare Example 1, Lot
1A. The product was spray dried to prepare a solid, powder product with a
moisture content of 3.53% (prior to testing).
Comparison with Reax 85-A in Disperse Dyestuffs--Reax 85-A is produced by
sulfonmethylation of kraft lignin and is considered the commercial
lignosulfonate of choice. It is available from Westvaco, New York, N.Y.
The product of the invention was compared at equal use rates.
______________________________________
A) Without dye addition:
Physical Properties
Dispersant Reax 85-A Lot 1A-3
______________________________________
1. Foam Test-Initial
340 ml 68
Foam Test-2 Minutes
108 ml 6
2. Transmission: .4578 .3494
Absorbance at 380 nm
______________________________________
______________________________________
B) Reduction Evaluation - Disperse Blue
Color Index No. 165:1
% Strength
______________________________________
Standard without heating and non-reducing
100.0
dispersant (dye only)
Standard with heating (shows reduction)
93.2
Lot 1A-3 dispersant 70.6
Reax 85-A (Prior Art) 65.7
Heating is at 265.degree. F. under pressure.
______________________________________
TABLE 9
______________________________________
Disperse Dye Performance and Physical Characteristics of
Dispersion-Disperse Blue (C.I. No. 79)
Lot 1A-3
Reax 85-A Dispersant
______________________________________
Dispersion Test 27 Seconds 12 Seconds
(filtering time)
pH 9.7 9.2
Viscosity 40 cps 30 cps
Specking* 4/5 5
Foam Initial 50.8 ml 16.9 ml
Foam-after 2 minutes
25.4 ml 8.5 ml
Strength (%) 100 98.8
intensity of color
______________________________________
*1 Poorest
5 Best
Grinding times were the same with both dispersants.
TABLE 10
______________________________________
Comparison with Marasperse CBOS-4.sup.1 in Vat Dyes
(CBOS-4- a sulfomethylated lignosulfonate, i.e.
oxy-lignin material residue from oxidation of lignin
Vat Black (Color Index No. 25)
CBOS-4 Lot 1A-3 Dispersant
______________________________________
Dispersion Test
8 seconds 6 seconds
(filtering time)
pH 8.9 9.4
Viscosity 30 cps 270 cps
Specking 5 5+
Foam.sup.2 -Initial
6.8 ml 8.5 ml
Foam.sup.2 -after 2
1.7 1.7
minutes
Strength % 100 98.2
______________________________________
.sup.1 Available from DaishowaReed of Greenwich, CT.
.sup.2 The industry standard for vat dyes AATCCmethod DD9B (Klopman Foam
Test)
From the above data it is seen that the dispersants of this invention are
better than the prior art dispersants.
The above test data show that not only is the Lot 1A-3 dispersant an
excellent non-reducing dispersant with a highly reduction prone dye
Disperse Blue C.I. No. 165:1, but the dispersant is also useful for vat
dyes. Such cross-over capability is not displayed for REAX 85-A which
cannot be used in vat dyes because of unacceptably high viscosity. In the
above tests for any dispersant, lower viscosity is desirable especially
for disperse dyes. Low foaming is equally desirable.
"Specking" in the above tests is defined as degree of agglomeration after
dispersion and is determined by appearance of the filter cloth after the
dispersion test. It also measures stability of the dispersion.
"Strength" means intensity of color and indicates reduction.
In the test for Vat Black (C.I. No. 25) the higher viscosity for Lot 1A-3
dispersant shows, however, a finer grind (which may increase viscosity)
yet it is noted that filtering time is less which indicates excellent
dispersion.
The above tests are based on AATCC (American Association of Textile and
Colorant Chemists) tests but are more severe e.g. for filtering.
While we have demonstrated the novel and outstanding properties for the
novel compounds, it is evident that these have a number of applications as
dispersants and for other purposes; however, the invention is sought to be
defined by the claims herein and by the reasonable scope of these claims.
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