TYPICAL FORMULATION INGREDIENTS AND PROPERTIES
APPLICABLE BASE POLYMER PROPERTIES
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.
In acrylic emulsion based sealants (table above), PIBs have been used as a plasticizing resin to increase the solids content and thereby reduce shrinkage. A broad product line with a wide range of properties can be developed by only varying the pigment-to-binder ratio. With high pigment-to-binder ratios, water based acrylic sealants are able to compete against the low cost polyvinyl acetate and vinyl acrylic sealants. On the other end of the formulation spectrum, low pigment-to-binder ratios provide competition to high performance sealants. In this way acrylics can compete against the polyurethane and silicone sealants meeting ASTM C 920.
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