Dependence of adhesion properties of SMR L based adhesive on molecular weight of rubber

Abstract

The viscosity, loop tack, peel and shear strength of five different molecular weights of standard Malaysian rubber based pressure sensitive adhesive were studied. Coumarone-indene resin and toluene were used as the tackifier and solvent respectively throughout the experiment. The adhesive was coated on polyethylene terephthalate substrate at a coating thickness of 30, 60, 90 and 120 mm using a Sheen hand coater. Viscosity of the adhesive was determined by a Haake rotary viscometer whereas loop tack, shear and peel strength was measured by a Llyod adhesion tester. Results show that viscosity of adhesive increases with increasing molecular weight of rubber. However, loop tack, shear and peel strength exhibit maximum value at a molecular weight of 8?5610 4 where maximum wettability of adhesive on the substrate occurs. The adhesion property increases with coating thickness at this optimum molecular weight of rubber.

Adhesion property of crosslinked epoxidized (natural rubber)/(acrylonitrile‐butadiene) rubber blend adhesives in the presence of petro resin tackifier

“…For a fixed coating thickness, the 90° peel test indicates the highest peel strength followed by 180° and T‐peel tests. This phenomenon is associated with the angle of testing, where higher strain‐induced crystallization of the rubber occurs in the 90° peel test compared with the other two modes of peel test; hence, the adhesive layer itself cannot easily be ruptured . The surface morphology of adhesives on base stock after the 90° peel test is studied by SEM.…”

“…Figure 2 shows that 120-lm coated sample indicates a higher tack value than the 30-lm coated sample. This result is attributed to the adhesive volume present, which enhances the viscoelastic response to form adequate tack property at 120-lm coated thickness [13,14]. Figure 3 shows the effect of rate of testing on tack at the optimum benzoyl peroxide loading of 2 phr for 30-lm and 120-lm coating thicknesses.…”

Effect of blend ratio and testing rate on the adhesion properties of pressure-sensitive adhesives prepared from epoxidized natural rubber 25/acrylonitrile–butadiene rubber blend

“…This phenomenon is associated with the angle of testing where higher strain-induced crystallization of the rubber occurs in the 90° peel test compared with the other two modes of peel test at low coating thickness, so that the adhesive layer itself cannot easily be ruptured. 12,13 As the coating thickness is further increased, peel strength increases steadily with coating thickness in 180° peel test, where 180° peel test is a combination of tensile and shear stress. This observation suggests that 180° peel test requires the higher peeling force to separate the mechanical interlocking and anchorage of the adhesive in pores and irregularities in the substrate.…”

Effect of molecular weight and testing rate on peel and shear strength of epoxidized natural rubber (ENR 50)‐based adhesives

“…FTIR study has been used to see differences in peaks with changes in molecular weight of ENR 50 and variation of coumarone‐indene resin content. Our previous study focuses on the dependence of adhesion property on molecular weight at different coating thickness 4–7. The aim of this study is to investigate the effect of molecular weight and testing rate on adhesion property of ENR.…”