Waterborne polyvinyl acetate adhesives have the same base latex resin that is used in wood glues. These adhesives provide a low to medium performance, inexpensive adhesive that dries to a relatively rigid material. A typical formulation consists of polyvinyl acetate latex, filler, plasticizer (for improved flexibility), and water. Since these adhesives set by evaporation, they shrink on drying more than 100% solids adhesives.
RESULTING PROPERTIES
The low viscosity of the PVAc water emulsion and its fast setting capability provide an excellent adhesive for wood and other porous substrates. The formulations in the table above are claimed to have improved water resistance over conventional unmodified polyvinyl acetate emulsions.
Both formulations A and B have been used for bonding aluminum foil to chipboard. Formulation C has been used to bond cloth backed PVC to porous surfaces. Formulations B and C dries to a somewhat rubbery film by virtue of the plasticizer component. The adhesive has good resistance to water and good adhesion to most substrates. Casein resins are thermosetting and contribute to the good water resistance properties of Formulation A.
