Effect of particle structure on the peel strength and heat resistance properties of vinyl acetate/acrylate latexes laminating adhesives

The concept of using particle structure design to prepare emulsion laminating adhesives (LAs) for improving both the peel strength and heat resistance properties has been investigated. The homogeneous particle latices based on vinyl acetate/acrylate copolymer (samples 1–3) were synthesized by seeded semicontinuous emulsion polymerization with different chain transfer agent (CTA) contents but with no functional monomers, while the core-shell structure crosslinkable latices (samples 4 and 5) were prepared through multistage polymerization technique. The emulsion particle structure was investigated by TEM and particle size analyzer. The results indicate that the average emulsion particle diameter is about 130 nm and the particles grow without secondary nucleation. Samples 1 and 2 prepared with 0.7 and 0.5 phm (per hundred gram monomer) CTA respectively, show high peel strength but poor heat resistance property. On the contrary, the sample 3 prepared with 0.1-phm CTA exhibits low peel strength but relatively good heat resistance. However, sample 4, which was synthesized with 0.5-phm CTA and 0.4-phm acetoacetoxy ethyl methacrylate (AAEM) in core but 0.5-phm CTA and 0.6-phm AAEM in shell stages, shows high peel strength (1032.9 g/in.) and good heat resistance property (524.9 g/in.). In addition, sample 5 also demonstrates high peel strength (987.2 g/in.) and good heat resistance property (643.5 g/in.) when it was synthesized using 0.1-phm CTA but no AAEM in core, 0.36-phm CTA and 0.75-phm AAEM in shell stages. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010