Acrylic emulsion based sealants have taken over many of the applications where a higher movement capability is required than for polyvinyl acetate sealants. Acrylic sealants can also be used outdoors, whereas the polyvinyl acetate sealants have inferior exterior durability.
Acrylic emulsion polymers are ideally suited to the formulation of medium performance sealants. There is a significant variation in the types of base polymer emulsions that are available, and these emulsions are easy to formulate. This gives the formulator a wide latitude for compounding to meet specific requirements. Sealants based on acrylic emulsions provide tough, elastic systems, with high adhesion and durability, and they are very environmentally friendly and easy to use.
RESULTING PROPERTIES
The acrylic latex polymer can tolerate large amounts of plasticizer without its properties being seriously affected. Plasticizers that are generally used in waterbased acrylic sealants are non-volatile types such as benzylbutyl phthalate, dipropylene glycol dibenzoate, and propylene glycol alkyl phenyl ether. The formulation above will meet the performance requirements of ASTM C 920 except for percent weight loss after heat aging.
