Thickening agent, filler content

Fillers (calcium carbonate, calcium sulfate, aluminum oxide, bentonites, wood flour) increase the solid content of the dispersion, and they are added up to 50%, based on PVAc. The purpose of their addition is the reduction of the penetration depth, a thixotropic behavior of the adhesive, gap filling properties, and the reduction of the adhesive costs. Disadvantages can be the increase of the white point and possibly the more marked tool wear rate due to greater hardness of the adhesive. Other components in PVAc formulations are defoamers, stabilizers, filler dispersants, preservatives, thickeners (hydro-xyethylcellulose, carboxymethylcellulose), poly(vinyl alcohols), starch, wetting agents, tackifiers, solvents (alcohols, ketones, esters), flame retardants, and others. 

Clear and translucent sealants consist primarily of polymer dispersion (ca. 75-95 % by weight) and various formulation auxiliaries such as plasticizers, de-foamers, preservatives, thickeners, and freeze-thaw agents. Since fillers are not used, formulation solids content is essentially defined by the solids content of the polymer dispersion used, which for currently available materials, is typically <65 %. Higher water contents promote slower sealant drying rates. Relatively hard acrylic copolymers (Tg = -10 to -1-10 °C) are needed in clear sealants to minimize surface tack and subsequent dirt pick-up. Translucent sealants are formulated similarly but with small amounts of fumed silica thickener to adjust flow properties. 

---