Effect of zinc oxide on the viscosity, tack, and peel strength of ENR 25‐based pressure‐sensitive adhesives

Abstract

Viscosity, loop tack, and peel strength of epoxidized natural rubber (ENR 25 grade)-based pressure-sensitive adhesive was studied in the presence of zinc oxide. The zinc oxide concentration was varied from 10-50 parts per hundred parts of rubber (phr). Coumarone-indene resin with loading from 20 to 100 phr was chosen as the tackifier resin. Toluene was used as the solvent throughout the experiment. The adhesive was coated on the substrate using a SHEEN hand coater to give a coating thickness of 60 mm. Viscosity of the adhesive was determined by a HAAKE Rotary Viscometer whereas the loop tack and peel strength were measured by a Llyod Adhesion Tester operating at 30 cm/min. Results show that viscosity and loop tack of adhesive increases with increasing zinc oxide concentration. For the peel strength, it increases with zinc oxide concentration up to 30-40 phr and drops after the maximum value. This observation is associated with the effect of varying degree of wettability of the adhesive on the substrate. However, for a fixed zinc oxide concentration, loop tack and peel strength exhibit maximum value at 80 phr resin loading after which both properties decrease with further addition of resin, an observation which is attributed to phase inversion. From this study, the optimum adhesion property is achieved by using 40 phr zinc oxide and 80 phr coumarone-indene resin.

Adhesion property of epoxidized natural rubber (ENR)-based adhesives containing calcium carbonate

“…Also, a gradual drop of shear strength with increasing tackifier loading is also observed. Recently, we have carried out a study on the effect of zinc oxide on the viscosity, tack and peel strength of ENR 25-based pressure-sensitive adhesives [7]. It is shown that viscosity and loop tack of adhesive increases with increasing zinc oxide concentration.…”

Adhesion properties of styrene-butadiene rubber (SBR)/Standard Malaysian Rubber (SMR L)-based adhesives in the presence of phenol formaldehyde resin

“…Recently, we have carried out several investigations on the viscosity, tack, peel and shear strength of natural rubber (NR) and epoxidized natural rubber (ENR) [1][2][3][4][5]. It has been shown that the viscosity and tack of natural rubber-based adhesive increases with resin content due to the concentration effect of tackifier resin.…”

Effect of zinc oxide on the viscosity and adhesion property of epoxidized natural rubber/acrylonitrile‐butadiene rubber‐based pressure‐sensitive adhesives

“…It is obvious from the graph that viscosity of adhesive increases with an increase in zinc oxide concentration, and the rate of increase is faster as the filler content is increased. This observation is attributed to the thickening effect of the zinc oxide, which acts as the filler in the adhesive formulation [8]. This finding suggests that greater interaction between the filler and adhesive system occurs.…”