Rheological Additives for Crop Protection - Elementis Specialties

ELEMENTIS SPECIALTIES Rheological Additives
Aqueous-Phase
Aqueous-Phase
Thickeners
Thickeners
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ELEMENTIS Specialties rheological
additives can be broardly divided into
thickeners for aqueous and non-aqueous
systems. Clay and polymer based
additives provide the desired flow control
to water, oils or solvents to stabilise
formulations.
BENTONE BENTONE ® Hydrophilic
Hydrophilic Hydrophilic Clays
Clays
BENTONE ® MA, EW and LT additives
are produces from hectorite clay.
Hectorite is a natural material and is the
preferred clay for aqueous systems. It
offers high swelling and suspension
efficiency. Hectorite has a low iron
content - important in the presence of
iron-sensitive actives. Its inorganic
nature provides thermostable flow
control.
BENTONE ® MA and EW additives form
gels by producing an open,
3-dimensional network of the individual
clay platelets as shown in Figure 5.
BENTONE ® LT forms a similar network,
but it is strengthened by the presence of
a special cellulose, greatly enhancing
stability and thickening characteristics.
BENTONE ® LT is specially modified to
be stable over a broader range, pH 3-11,
and is the least sensitive to electrolytes.
The range of ELEMENTIS Specialties
products meeting EPA requirements can
be requested from our regulatory
department.
Non-ionic surfactants, if they are highly
ethoxylated, can adsorb onto the clay
surface. This rarely causes problems
either in flow control or activity of the
formulation.
Anionic surfactants can act as dispersing
agents and weaken the gel structure.
Alternatives that eliminate or minimise
any problems can normally be found.
However, cationic surfactants interact
strongly and should be avoided.
BENTONE® hydrophilic clays are used
alone or in combination with other
thickeners. Their use with xanthan gum
and other polysaccharides is particularly
effective in controlling suspension.