Paints and polishes: In the case of emulsion paints, the role of bentonite is as an
emulsifying agent (as above) to prevent settling of pigment. In water paints and polishes, it is
used to increase viscosity and to make pastes.

Paper, oil cloth and linoleum: Where off-colour is acceptable or where colour is not
important, calcium bentonite can be used in the manufacture of paper, oil cloth (smooth paper
thickly coated with linseed oil) and linoleum (floor-covering canvas thickly coated with
linseed oil). Addition of 10% bentonite, by virtue of its bonding power, helps to improve the
96 Kaulir Kisor Chatterjee
retention of china clay (used as a coating material in high quality paper to make the surface
glazed) from 45% to 84%. In addition, bentonite increases the smooth feel of the surface.

Sealants: Sealant is an organic substance soft enough to pour or extrude and capable
of subsequent hardening to form a permanent bond with the substance. One of the
components of a sealant is what is called pigment, which performs various functions like
acting as a filler, colouring, shielding ultraviolet light, etc. Bentonite acts as an excellent
thickener for water emulsion type sealants. Montmorillonite particles exist in the form
agglomerates up to several millimetres in size, but in 5-6% concentration in water, they break
down to less than 0.1 micrometer. These nano-sized particles enable even the heaviest of the
pigments to remain in suspension.

Animal and poultry feed: Bentonite is used as a pellet-binder. Besides, it provides
additional mineral nutrients. Its use increases egg size and shell hormones.