TREATED INORGANIC PIGMENTS HAVING IMPROVED BULK FLOW
The disclosure provides a treated inorganic pigment, typically a titanium dioxide pigment, comprising an inorganic pigment having a surface area of about 30 to about 75 m 2 /g; wherein the pigment surface is treated with an organic treating agent comprising a polyalkanol alkane or a polyalkanol amine, present in the amount of at least about 1.5%, based on the total weight of the treated pigment; wherein the treated inorganic pigment has a RHI (rat hole index) of about 7 to about 11. The treated inorganic pigments have better flow characteristics, and generally fewer lumps.
1 . A treated inorganic pigment comprising an inorganic pigment having a pigment surface area of about 30 to about 75 m 2 /g; wherein the pigment surface is treated with an organic treating agent comprising a polyalkanol alkane or a polyalkanol amine, present in the amount of at least about 1.5%, based on the total weight of the treated pigment; wherein the treated inorganic pigment has a RHI (rat hole index) of about 7 to about 11.
2 . The treated inorganic pigment of claim 1 wherein the inorganic pigment is ZnS, TiO 2 , CaCO 3 , BaSO 4 , ZnO, MoS 2 , silica, talc or day.
3 . The treated inorganic pigment of claim 2 wherein the inorganic pigment is titanium dioxide.
4 . The treated inorganic pigment of claim 1 wherein the surface area is about 40 to about 70 m 2 /g.
5 . The treated inorganic pigment of claim 4 wherein the surface area is about 45 to about 65 m 2 /g.
6 . The treated inorganic pigment of claim 1 wherein the organic treating agent is a polyalkanol alkane.
7 . The treated inorganic pigment of claim 6 wherein the polyalkanol alkane is trimethylolpropane, trimethylolethane, glycerol, ethylene glycol, propylene glycol, 1,3 propanediol, or pentaerythritol.
8 . The treated inorganic pigment of claim 7 wherein the polyalkanol alkane is trimethylolpropane or trimethylolethane.
9 . The treated inorganic pigment of claim 1 wherein the organic treating agent is a polyalkanol amine.
10 . The treated inorganic pigment of claim 9 wherein the polyalkanol amine is 2-amino-2-methyl-1-propanol, triethanol amine, monoethanol amine, diethanol amine, 1-amino 2-propanol, or 2-amino ethanol.
11 . The treated inorganic pigment of claim 10 wherein the polyalkanol amine is 2-amino-2-methyl-1-propanol, triethanol amine.
12 . The treated inorganic pigment of claim 1 wherein the organic treating agent is present in the amount of at least about 1.8%, based on the total weight of the treated pigment.
13 . The treated inorganic pigment of claim 12 wherein the organic treating agent is present in the amount of at least about 2%, based on the total weight of the treated pigment.
14 . The treated inorganic pigment of claim 1 further treated with metal oxides.
15 . The treated inorganic pigment of claim 14 wherein the metal oxide treatment comprises silica, alumina, tungsten, zirconia, zinc oxide, or molybdenum oxide.
16 . The treated inorganic pigment of claim 14 wherein the metal oxides are present in the amount of 0.1 to about 20 wt %, based on the total weight of the treated pigment.
17 . The treated inorganic pigment of claim 1 wherein the treated inorganic pigment has a RHI of about 7 to about 10.
18 . The treated inorganic pigment of claim 17 wherein the treated inorganic pigment has a RHI of about 7 to about 9.