the properties of an adhesive are a function of its adhesive or tacky properties and its cohesive or internal strength properties . generally , varying the polymer properties to increase the cohesive strength of the adhesive will lower the tack of the adhesive . an improvement in both the cohesive and adhesive properties of an adhesive comprising a polymer and a tackifier by using a polymer which comprises a plastic grafted onto an elastomer ; and a tackifier which is more compatible in the elastomer .