Pigment dispersants are developed with new SMA esters for water-based coatings and inks

Improving pigment dispersion is one of the important energys of water-based inks and coatings. The three elements of dispersion are the wetting of pigment aggregates, the dispersion of aggregates into fragmented primary particles, and the stability of dispersed particles. In general, full wetting of dispersed compositions can be achieved, but its long-term stability
(
maintaining particle dispersion
)
is not necessarily possible. This can lead to problems such as geling, loss of light, or transparency
(
for opaque pigments, i.e.decrease. The key to getting good pigment wetting
/
processing is to improve the wetting of pigments by utilizing polymers with chemical groups that can be affined to the particle surface. In addition, polymer structures can be designed with sufficient bit resistance stability to provide good long-term dispersion stability by keeping particles dispersed.
Water Repulsion Index
Styrene Malay acid copolymer esters
(SMA
®
ester
)
has been successfully applied to water-based and solvent-based pigment dispersion, but further research is needed to understand the workings of these materials.
SMA
esters are polymer surfactants that contain both hydrophobic acids, acids and esters, as well as water-repugnant styrene and ester chain groups (
R
), as shown in figure
1
.
To further quantify the balance between hydrophobic and water-repugnance groups in molecules, the following concept of water repugnance index is defined: the total molecular mass of water-repugnance groups
/SMA
ester esters.
two of the most successful methods for industrialization as pigment dispersants
SMA
:
SMA Ester A
and
SMA Ester B
, with a water repercide index of
74.3
and
71.1
, respectively. In order to design a better dispersant, it is natural to think that the new esters may have to have a water repugnant index value similar to
SMA Ester A
and
SMA Ester B
. To this end,
a series of
SMA

alkyl esters
(
styrene
/
Malay acid anhydrides in a range of
1
:
1

4
:
1
; Alkyl alcohols used range from
C3
propanol to
C18
18 alcohols
)
. Through the introduction of these groups, the resulting ester moisture repercide index range of
66.5
to
77.1
, which covers
SMA Esters A
and
B
, as shown in Table
1
.
in order to test the pigment dispersion of the new esters, the pigment dispersion was prepared with Lisol bao red, indigo blue and diacetylamine yellow pigment, which is
SMA Ester A
and
SMA Ester B
tested the initial viscosity of the dispersion, the viscosity after storage placement, the color spread, and the ink properties. Unfortunately, all dispersions prepared with new esters are more viscous and less color-spreading than dispersions prepared by
SMA Ester A
and
SMA Ester B
. In this regard, it may be argued that while the water repulsion index of the dispersant may be important, alcohols and the type of ester chain obtained may also be important. Therefore, other esters are prepared with different types of alcohols. The water repudiation index of these esters is shown in table
2
and is compared with the
SMA EsterA
and
SMA Ester B
. It should be noted that all new synthetic esters except
NTX 7643
have a water repugnent index value between the values of
SMA Esters A
and
B

(71.1 - 74.3)
.
to test the performance of these esters, dispersions were prepared with the same red, blue and yellow pigments. In addition, the foaming and deblbling of the ester solutions were tested, and the value of the
VOC
was measured.
experimental part
the
of raw materials and dispersion formula:
.
Solbao Red Pigment:
LR1392
,
MagruderColor Company
;
·
blue pigment:
BW 1531
,
Pacific Coast Enterprises
;
·
double acetylamine yellow pigment:
CibaYellow BAT
,
Ciba Geigy
;
·
deboulant:
Byk 022
,
Byk Chemie
;
·
SMA
resins:
Sartomer Company, Inc.
;
ink formula consists of:
:
.
acrylic solution:
Joncryl63
,
BASFCorporation
;
·
with acrylic emulsion:
ECO2177
,
BASFCorporation
blistering
/
defrosting test
SMA
ester foam performance is important because if too much foam is produced during high shear dispersion, it will reduce the efficiency of the dispersant wetting pigment aggregate, resulting in a decrease in color display. In addition, if there is too much air trapped, the fluid characteristics of the dispersion will be difficult to control during the painting process. In order to test the foaming
/
deblistering characteristics, each dispersant solution was prepared with the same amount of solids, and each solution was taken
125 mL
and placed in a tube sealed with a wooden plug. Each drum rotates
10
times, and when the rotation stops, each drum is placed horizontally, recording the initial volume readings, and then recording the
30s
,
60s
and
300s
, respectively. The time after mixing is graphed at the foam height value of each solution (as shown in
2
2). The
(zero foam value
at the 125 mL point. It is worth noting that the initial foam volume of the commercially available
SMA esters A
and
B
at zero seconds is high and the foam is not easily eliminated, while for each newly synthesized ester, the initial foam is highly low and the foam is eliminated faster.
VOC


VOC
for each
SMA
ester class because many coating and ink formulations focus on its components
VOC
value, the method is to take
1g
placed in the aluminum disk, in
110
degrees C heating
1h
, and then weigh the quality of the aluminum disk, calculate the mass loss. Compare the four newly prepared esters with the values of
SMA EsterA
and
B
, and the results are shown in table
3
. Newly synthesized esters
NTX 7639
's
VOC
is lower than
Ester A
but slightly higher than
Ester B
.
the
step, compare newly synthesized
SMA
esters with
SMA Ester A
and
SMA Ester B
and prepare Dispersions of the appropriate pigment dosing amount of indigo and lisol bao red: the phosphon is
38.75%
, and the opposite saul red is
37%
. Performance focuses on the viscosity of dispersions and inks, coloring force, color intensity, and scratching appearance
Leneta
paper cards.
all the
SMA
are used in the preparation of indigo and lisol red dispersions. Based on this screening, the best performing esters were selected for further preparation of diacetylamine yellow pigment dispersions. Dispersion system preparation
SMA
as the only dispersed resin. The yanki ratio of the prepared composition is
4.75/1
. The addition method involves adding the liquid parts into the mixer, mixing them evenly in
20s
, and then adding the pigments into three parts on average, each of which is mixed and moistened before adding the next serving. After all pigments are added, the mixture
(
pre-dispersion
)
10min
the pig
ment dispersion process begins.
the components are premixed, the composition is added to the
Eiger Mini-100
horizontal media grinding, grinding with
0.8mm
of about
75g
of
YTZ
grinding medium, operating speed
5000

/
minutes, grinding sample. Each sample is ground at
10min
. Add 28g water
each
composition, making the total processing
400g
. The percentages of pigments and resins in each of the following compositions are processed
400g
of 400g.
to the indisin,
The SMA Ester A
the dispersion is too thick to grind, so no further tests were carried out on this sample. The same
is also
for
acetylamine yellow pigment dispersions containing SMAEster B and
SMA Ester A.
processing workload can be confirmed by current data milled during processing. In addition, the increase in temperature during sample processing can also confirm the high shear force produced during dispersion. The generation of high shear forces usually results in better dispersion and better color display.
the system of
, the formula prepared with the indigo blue and Lisolbao red dispersion system is shown in appendix tables
4
and
5
respectively.
result of the indigo blue and Lisolbo red dispersions, only the newly synthesized
SMA
NTX 7636

,
7638
,
7639
and
7643
are used to prepare diacetylamide yellow pigment dispersions for evaluation and contrast with
SMA Ester A
and
SMA Ester
. The formula is shown in appendix
6
.
the color intensity test and calculation
the purpose of evaluating the color intensity is to determine the degree of color display caused by the grinding process. The color intensity of the dispersion is measured by scraping each formula on
Leneta 3NT-4 paper, together with
other formulations of the same color. The coloring formula composition is a
50.00g
of Xuanwei
Extra WhiteTint Base
and
0.50g
dispersed in
hasschild
1min in a
1800/
-
-
centrifuge.
then designates a composition to evaluate the coloring intensity as a standard. with this standard