J. Dow-type Rolling Ball Tack Test forCrosslinked Polyacrylic Pressure-Sensitive Adhesive

Abstract

J. Dow-type rolling ball tack test for crosslinked poly（n-butyl acrylate-acrylic acid） pressure-sensitiveadhesive（ PSA） was done as a function of crosslinking agent content. To compare the result of ball tack testquantitatively, the following coefficient of friction, μ ׳ was proposed by solving the equation of motion for therolling ball on a slope of PSA tape:

where L is the length of approach run of a ball（ = 100 mm） and L is the distance until the stop point of ballon the slope of PSA tape. The ball has the kinetic and potential energies at the start point of contact withthe PSA tape. The μ ׳ means the criterion of absorption of these energies by the PSA tape. A specific contentof crosslinking agent showed the peak of μ ׳. On the other hand, the tack measured by the probe tack testdecreased gradually with an increase in the crosslinking agent content. Adhesion strength is influenced by twofactors: the interfacial adhesion and the cohesive strength of PSA. The tack measured by the probe tack test isinfluenced by only the interfacial adhesion. Whereas, the tack measured by the ball tack test is influenced byboth factors when the ball is stopped.