TABLE OF CONTENTS A number of acrylic resins are used for bonding cloth, plastics, leather, and, in some cases, metal foils. The acrylic monomers most commonly used in adhesives are ethyl acrylate, methyl acrylate, methacrylic acid, acrylic acid, acrylamide, and acrylonitrile. The polymers or copolymers are soluble in common organic solvents and can be supplied in much the same manner as other solvent-based systems. In addition, the polymers are soluble in the monomers. When a catalyst is added, monomers polymerize, thus providing good bonding to glass and to plastic surfaces of similar composition (e.g., polymethylmethacrylate). [1 ,2 ,3 ]
A variety of acrylic copolymers are prepared by emulsion polymerization. A number of acrylic adhesives that are called "reactive adhesives," "modified acrylics," "second-generation acrylics," or "reactive-fluid adhesives" have become available over the years. These formulations polymerize in the glue line and become an integral part of an adhesive assembly.
The "first-generation acrylic adhesives" cover adhesives that used solutions of polymers, usually rubber, in methacrylate monomers, and involved polymerization of these monomers in the presence of a reinforcing resin. The newer compounds are based on a combination of different modifying polymers for acrylics and a surface activator. A modifying polymer reinforces and toughens the bond and provides a reactive chemical site, which acts as a catalyst in the presence of special activators. Adhesion takes place when the monomers and activators graft-polymerize in modifying the polymer in the glue line.
In commercial form, these acrylic adhesive systems consist of two components,...
