Hypalon® chlorosulfonated polyethylene provides unique value as a toughener for structural acrylic adhesives or what has become known as "second generation acrylic" adhesives. These adhesives are a 100% solids blend of monomeric materials which polymerize in the glue line to become an integral part of an adhesive assembly. While they resemble epoxies and polyurethane adhesives functionally, they differ technologically from these materials by using free radical cure cites rather than curing by ionic polymerization reactions. For this reason, they do not require careful metering and mixing for full efficiency. The adhesives are characterized by providing excellent high peel and shear strength along with close to instant bonding speeds. In addition, the adhesives are able to bond through oil surfaces without the need for careful surface preparation prior to bonding.