Journal of Applied Polymer Science, Vol.93, No.6, 2889-2895, 2004
UV curable pressure-sensitive adhesives for fabricating semiconductors. II. The effect of functionality of acrylate monomers on the adhesive properties
In an attempt to control the adhesive properties of acrylic copolymer-based pressure-sensitive adhesives, a series of multifunctional acrylate monomers were added and UV cured. The adhesive compound with a difunctional monomer had increased peel strength after UV curing. On the other hand, the compound with a tri- or more functional (polyfunctional) monomer had markedly decreased strength after UV curing. Those adhesives containing any polyfunctional monomer also showed much higher storage modulus than an adhesive containing a difunctional monomer. The greater volume contraction of UV-cured polyfunctional monomer suggested microvoids at the interface between the adhesive layer and the adherent, resulting in poor strength. Estimated values of the peel strength of UV-cured adhesives according to the theoretical equations proved that the strength is approximately inversely proportional to the elastic moduli. (C) 2004 Wiley Periodicals, Inc.
Keywords:pressure-sensitive adhesives;UV curing;acrylic copolymer;multifunctional monomers;peel strength