Effect of Bimodality on the Adhesive Properties of Pressure Sensitive Adhesives: Role of Bimodal Particle Size and Molecular Weight Distributions

Abstract

A one-pot, two-step miniemulsion polymerization approach was successfully used to create poly(2-ethyl hexyl acrylate/methyl methacrylate/acrylic acid) pressure sensitive adhesives with well-defined and predictable bimodal particle size distributions (PSDs) or bimodal molecular weight distributions (MWDs). The resulting viscoelastic (shear storage and loss moduli) and adhesive properties (i.e., loop tack, peel strength, and shear strength) were tested and compared to monomodal distributions of either particle size or molecular weight along with bimodal distributions created by postpolymerization blending. The results indicated that in situ bimodal MWDs offered superior values of PSA properties when compared to either monomodal MWDs or postpolymerization blends. Viscoelastic analysis of the in situ bimodal MWD samples showed that the proposed approach can effectively vary the MWDs and cross-linking densities of the resulting PSAs, thus tailoring the final properties. In comparison, the in situ bimodal PSD latexes did not show significant differences in viscoelastic behavior, but they exhibited large differences in PSA properties.

Synthesis of a glucose-based surfmer and its copolymerization with n-butyl acrylate for emulsion pressure sensitive adhesives

“…12, the higher the particle size (41, 122 and 316 nm for 10%, 18% and 25% of BGMAH, respectively) the higher are tack, peel and shear resistance values. Qu et al [48] and Fonseca et al [47] reported the similar findings. However, their copolymers had fixed copolymer composition and similar gel phase, MWD and T g values.…”

“…PSD mainly influences film formation and latex viscosity; however, it has also been shown to affect adhesive properties [27,47,48]. Despite the fact that all the emulsions had monomodal PSD (Fig.…”

Bioadhesives: A Review

“…[9,10] Qie and Dub e [9] produced butyl acrylate/methyl methacrylate/hydroxyethyl methacrylate/acrylic acid emulsion latexes that showed remarkable improvements to shear strength without compromising tack. Some interesting ideas on overcoming this have been reported.…”

Siloxane‐modified polyacrylate low‐residual pressure‐sensitive adhesive with high peeling strength

“…To improve the cohesion of the PSAs without sacrifices in the tack and peeling strength, KH560, a siloxane with unique and better dry and wet adhesion properties, was selected to modify the polyacrylate PSA. In contrast to the decreases in the tack and peeling strength of the PSA modified by the commonly used vinyl silicone, 44 PSA modified by KH560 showed a better adhesive performance. Table V shows that when the content of KH560 was in excess of 2.0 wt % of the total monomer, the tack and peeling strength decreased slightly.…”