Producing a solid pigment preparation in the form of granules by spray drying
A process for producing a solid pigment preparation in the form of granules which comprises atomizing a suspension comprising (A0) 30% to 90% of a solvent component, (A1) 2% to 60% of a pigment component; (A2) 0% to 50% of a first filler component, and (A3) 10% to 70% of a surface-active additive component based on the sum of the components (A1) and (A2); contacting formed droplets with a gas stream having a predetermined temperature to dry the droplets to obtain granules having a predetermined residual moisture content, the droplets are exposed to an aerosol comprising a solid second filler component; and separating the granules from the gas stream.
1. A process for producing a solid pigment preparation in the form of granules comprising:
(a) atomizing a suspension comprising
(A0) 30% to 90% by weight of a solvent component based on the overall weight of the suspension;
(A1) 2% to 60% by weight of a pigment component based on the overall weight of the suspension;
(A2) 0.1% to 50% by weight of a first filler component based on the overall weight of the suspension;
(A3) 10% to 70% by weight of a surface-active additive component based on a sum total of the weights of said components (A1) and (A2);
wherein the sum total of weight fractions of all components, based on the overall weight, is 100% by weight,
in an atomizing apparatus, thereby obtaining droplets of liquid;
(b) at least partially exposing, before reaching a predetermined residual moisture content, the droplets of liquid obtained by the atomization to an aerosol comprising (A4) a solid second filler component and contacting the exposed droplets with a gas stream having a predetermined temperature to dry the droplets to obtain granules comprising the predetermined residual moisture content, wherein a content of the second filler is from 0.01 to 2 wt. % based on the obtained granules, and
(c) separating the obtained granules from the gas stream,
wherein the obtained granules have a median particle size in a range of from 10 μm to 5000 μm, and
wherein the first and second filler components are different.
2. The process according to claim 1 , wherein the granularity of the suspension in (a) has a value in the range from 0.01 μm to 10 μm.
3. The process according to claim 1 , wherein the temperature of the gas stream during the contacting in (b) is in the range from 70° C. to 250° C.
4. The process according to claim 1 , wherein the predetermined residual moisture content of the granule is not more than 5% by weight based on the overall weight of the granules.
5. The process according to claim 1 , wherein the solid second filler component in the aerosol comprises at least one solid selected from the group consisting of silica, alumina, titania, zirconia, and barium sulfate.
6. The process according to claim 5 , wherein the solid second filler component comprises silica.
7. The process according to claim 1 , wherein the granules obtained comprise a pigment composition comprising
(A1) 5% to 90% by weight based on the overall weight of the composition of the pigment component;
(A2) 0.1% to 70% by weight based on overall weight of the composition of the first filler component;
(A3) 10% to 70% by weight of the surface-active additive component based on a sum total of the weights of said components (A1) and (A2),
(A4) 0.01% to 2% by weight based on overall weight of the composition of the solid second filler components; and
optionally, further components,
a sum total of weight fractions of all components, based on overall weight, being 100% by weight.
8. A solid pigment preparation in the form of granules obtained by the process according to claim 1 .
9. The process according to claim 1 , wherein the suspension of (a) comprises 0.1 to 40% by weight of (A2) the first filler component, based on the overall weight of the suspension.
10. The process according to claim 1 , wherein the suspension of (a) comprises 5 to 50% by weight of (A2) the first filler component, based on the overall weight of the suspension.
11. The process according to claim 1 , wherein the suspension of (a) comprises 10 to 50% by weight of (A2) the first filler component, based on the overall weight of the suspension.
12. The process according to claim 1 , wherein in (b) drying the droplets to obtain granules comprising the predetermined residual moisture content is carried out before or simultaneously with applying the second filler (A4).