Typical Formulation Ingredients
Phase
Ingredient
Parts by weight
A
Acrylic resin dispersion
A
Wetting agent (NUOSPERSE® FN 265, Elementis)
A
Pigment dispersing agent (NUOSPERSE® FX 605, Elementis)
A
Defoamer (DAPRO® DF 7005,Elementis)
A
Rheological additive (e.g., BENTONE® DE or BENTONE® EW, Elementis)
Resulting Properties
A broad product line with a wide range of properties can be developed by only varying the pigment-to-binder ratio. A typical formulation for plasticizer-free but flexible acrylic latex sealants is given above. It provides a high solids, rapid drying, paintable, and low cost formulation for gap filling applications. The binder’s low glass transition temperature allows for the formulation of sealants with outstanding low temperature flexibility without the need for external plasticizers.
In this formulation Bentone EW or DE replaces fumed silica which is traditionally used in this application. The main advantages of using hectorite clay over fumed silica are very high low-shear viscosity build, strong shear thinning and low shear stress at high shear flow for good extrudeability, excellent sag resistance, and low tendency for water pick-up when exposed to high humidity.