Use of silicone resins as dispersants
View Patent ↗The invention provides for the use of silicone resins obtainable by reacting a) an alkoxysiloxane of the general formula R a 2 Si ( OR 1 ) b O 4 - ( a + b ) 2 with b) one or more hydroxyl-containing polyesters, and if desired c) one or more low molecular weight alcohols, it being possible for the alkoxysilane to be reacted partially and completely, based on the amount of (OR 1 ) groups in a), but the reaction being taken at least to the point where a clear solution is obtained, as dispersants for solids for producing coatings, printing inks and/or print varnishes.
1. A method for dispersing a pigment in a medium which comprises adding to said medium at least one silicone resin which is obtained by reacting
a) an alkoxysiloxane of the general formula
R
a
2
Si
(
OR
1
)
b
O
4
-
(
a
+
b
)
2
where
R 1 is a lower alkyl group,
R 2 is an alkyl or phenyl group,
a is from 1.0 to 1.2,
b is from 0.5 to 1.0,
with the proviso that at least 50% by weight corresponds to the formula
[R 2 Si(OR 1 )O] n , n=3 to 8,
with
b) one or more hydroxyl-containing polyesters,
and, optionally,
c) one or more low molecular weight alcohols,
wherein it is possible for the alkoxysiloxane to be reacted partly or fully, based on the amount of (OR 1 ) groups in a), but the reaction being taken at least to the point where a clear solution is obtained.
2. The method according to claim 1 wherein R 1 is a C 1 –C 4 group.
3. The method according the claim 1 wherein R 1 is an ethyl radical.
4. The method according to claim 1 wherein R 2 a phenyl radical.
5. The method according to claim 1 wherein R 1 is an ethyl radical and R 2 is a phenyl radical.
6. The method according to claim 1 , wherein the hydroxyl-containing polyester is the reaction product of at least one dicarboxylic acid or derivative thereof and at least one diol.
7. The method according to claim 1 , wherein the hydroxyl-containing polyester is the reaction product of at least one hydroxycarboxylic acid and/or its lactone and at least one diol.
8. The method according to claim 1 , wherein the hydroxyl-containing polyester has a molar mass of from about 100 to about 10,000 g/mol.
9. The method according to claim 1 , wherein the low molecular weight alcohol is a monohydric to tetrahydric alcohol or an amino alcohol.
10. The method according to claim 1 , wherein the medium is a liquid.
11. The method according to claim 1 , wherein the medium is a solid.
12. The method according to claim 1 , wherein the pigment is an inorganic pigment selected from the group consisting of carbon blacks, titanium dioxide, zinc oxide, Prussian blue, iron oxides, cadmium sulfide, chromium pigment and sulfates of lead, zinc, barium, calcium and mixtures thereof or an organic pigment selected from the group consisting of azo, diazo, condensed azo, naphtol, metal complex, thioindigo, indanthrone, isoindanthrone, anthanthrone, anthraquinone, isodibenzanthrone, triphendioxazine, quinacridone, perylene, diketopyrrolopyrrole, and phthalocyanine pigments.
13. The method according to claim 1 , wherein the solid is a filler.
14. The method according to claim 13 , wherein the solid is selected from the group consisting of talc, kaolin, silicas, barytes, lime, oxides, silicates, zirconium oxides, titanium oxides, boron nitrides, silicon nitrides, boron carbides, mixed silicon-aluminum nitrides, metal titanates, magnetic oxides of transition metals, cobalt-doped iron oxides, ferrites, metals, and the alloys thereof, biocides, agrochemicals, and drugs.
15. The method according to claim 1 , wherein a low molecular weight alcohol is present and is selected from the group consisting of methanol, ethanol, propanol, isopropanol, 2-butanol, isobutanol, hexanol, dodecanol, ethylene glycol, propylene glycol, butanediol, hexanediol, diethylene glycol, dipropylene glycol, trimethylolethane, trimethylolpropane, pentaerythritol, ditrimethylolpropane, hexahydric alcohols, such as methanol, ethanol, propanol, isopropanol, 2-butanol, isobutanol, hexanol dodecanol, ethylene glycol, propylene glycol, butanediol, hexanediol, diethylene glycol , dipropylene glycol, trimethylolethane, trimethylolpropane, pentaerythritol, ditrimethylolpropane, alcohols, dipentaerythritol, 2-aminoethanol, 2-(2-aminoethylamino)ethanol, triethanolamine, diethanolamine, propanolamine, 2-amino-1,3-propanediol, 2-aminoisobutanol, aminohexanol, aminophenylethanol, and hydroxyethylpyridine.
16. A pigment paste which comprises at least one pigment and a silicone resin obtained by reacting
a) an alkoxysiloxane of the general formula
R
a
2
Si
(
OR
1
)
b
O
4
-
(
a
+
b
)
2
where
R 1 is a lower alkyl group,
R 2 is an alkyl or phenyl group,
a is from 1.0 to 1.2,
b is from 0.5 to 1.0,
with the proviso that at least 50% by weight corresponds to the formula
[R 2 Si(OR 1 )O] n , n=3 to 8,
with
(b) one or more hydroxyl-containing polyesters derived from at least one hydroxycarboxylic acid and/or the corresponding lactone, and at least one diol,
c) one or more low molecular weight alcohols,
wherein it is possible for the alkoxysiloxane to be reacted partly or fully, based on the amount of (OR 1 ) groups in a), but the reaction being taken at least to the point where a clear solution is obtained.
17. A printing ink or paint varnish which comprises a pigment and/or dye, optionally a solvent, and at least one silicone resin obtained by reacting
a) an alkoxysiloxane of the general formula
R
a
2
Si
(
OR
1
)
b
O
4
-
(
a
+
b
)
2
where
R 1 is a lower alkyl group,
R 2 is an alkyl or phenyl group,
a is from 1.0 to 1.2,
b is from 0.5 to 1.0,
with the proviso that at least 50% by weight corresponds to the formula
[R 2 Si(OR 1 )O] n , n=3 to 8,
with
(b) one or more hydroxyl-containing polyesters derived from at least one hydroxycarboxylic acid and/or the corresponding lactone, and at least one diol,
c) one or more low molecular weight alcohols,
wherein it is possible for the alkoxysiloxane to be reacted partly or fully, based on the amount of (OR 1 ) groups in a), but the reaction being taken at least to the point where a clear solution is obtained.
18. The printing ink or paint varnish according to claim 17 , wherein the pigment is carbon black.
19. A coating which comprises at least one solid, optionally a solvent, and at least one silicone resin obtained by reacting
a) an alkoxysiloxane of the general formula
R
a
2
Si
(
OR
1
)
b
O
4
-
(
a
+
b
)
2
where
R 1 is a lower alkyl group,
R 2 is an alkyl or phenyl group,
a is from 1.0 to 1.2,
b is from 0.5 to 1.0,
with the proviso that at least 50% by weight corresponds to the formula
[R 2 Si(OR 1 )O] n , n=3 to 8,
with
(b) one or more hydroxyl-containing polyesters derived from at least one hydroxycarboxylic acid and/or the corresponding lactone, and at least one diol,
c) one or more low molecular weight alcohols,
wherein it is possible for the alkoxysiloxane to be reacted partly or fully, based on the amount of (OR 1 ) groups in a), but the reaction being taken at least to the point where a clear solution is obtained.
20. The coating according to claim 19 which is a pigmented UV curable coating which comprises carbon black as the pigment.