Molecular parameters and their relation to the adhesive performance of acrylic pressure-sensitive adhesives

Abstract

Model acrylic pressure‐sensitive adhesives (PSAs) based on poly(2‐ethyl‐hexyl acrylate‐stat‐acrylic acid) and poly(n‐butyl acrylate‐stat‐acrylic acid) at 97.5/2.5 wt % were synthesized using semicontinuous emulsion and solution polymerizations. Microgels formed in the lattices retained their discrete network morphology in the film. In contrast, acrylic solution was essentially gel free and crosslinking in the film was provided by the reaction of acrylic acid and post added Al Acetyl Acetonate after solvent evaporation, which led to continuous network morphology. The difference in film network morphology caused significantly lower shear holding power for the film from emulsion PSA compared with that of solvent‐borne film. Unlike shear holding power, loop tack and peel of acrylic PSAs were mainly controlled by the same sol/gel molecular parameters, regardless of emulsion or solution PSAs. The important molecular parameters are sol‐to‐gel ratio, entanglement molecular weight, weight average molecular weight, and to a lesser extent, glass transition temperature. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2230–2244, 2001

Probing particle structure in waterborne pressure-sensitive adhesives with atomic force microscopy

“…They exhibit lower water resistance, [5,6] a tendency to whiten in moist atmospheres, and lower tack, adhesion and shear strengths. [7,8,9,10] On the positive side, polymer colloids offer a facile means to tailor the structure of adhesive films at the nanometer length scale [11]. Nanostructured particles have been used to create films with remarkable mechanical properties.…”

“…solvent-cast) copolymers in adhesives has established clear correlation between the molecular structure of films and their adhesive performance. For instance, the effects of factors such as gel content, [10] molecular weight, [13] and crosslinking [14] have been established. There is a much smaller body of work to correlate the molecular architecture and nanostructure of waterborne colloidal films with their adhesion properties.…”

Overview of Polymer Colloids: Preparation, Characterization, and Applications

“…There are many diverse areas where polymer colloids are utilized (47) ranging from coatings applications in paints (48), as a binder for paper coatings (49), in tire manufacturing (50), as toughening agents in rubber-toughened plastics (57), in pressure sensitive adhesives (52), to their use in medical diagnostics (53). Many industrial coatings applications still utilize solvent-based formulations and there is considerable environmental pressure to reduce VOC levels while still maintaining the desirable properties that are often obtained with solvent-based coatings.…”

Effect of Crosslinking Agent on Adhesion Properties of UV Curable 2-EHA/AA Pressure Sensitive Adhesive

“…1 The application of PSA products has been developed rapidly includes package, automotive, electric, medical, architectural industry and home appliance. [1][2][3][4][5]8 Acrylic PSAs, in general, are copolymerized with low T g monomers such as 2-ethylhexyl acrylate and n-butyl acrylate (n-BA) for tackiness and high T g monomer such as acrylic acid (AA) for cohesive strength of PSAs. 2 Acrylic acid is usually copolymerized with 50~90% major polymer because of carboxylic group in its structure is useful for crosslinking and modifying cohesive strength.…”

“…[1][2][3][4][5]8 Acrylic PSAs, in general, are copolymerized with low T g monomers such as 2-ethylhexyl acrylate and n-butyl acrylate (n-BA) for tackiness and high T g monomer such as acrylic acid (AA) for cohesive strength of PSAs. 2 Acrylic acid is usually copolymerized with 50~90% major polymer because of carboxylic group in its structure is useful for crosslinking and modifying cohesive strength. 2,6 As PSAs need to be able to wet the surface of a substrate and possess a low T g component to enable a tacky film to be obtained, they are usually prone to fail cohesively.…”