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Natural ultramicronized calcium carbonate and mixtures of fumed silica C natural ultramicronized calcium carbonate are proposed as a ller for solvent-based polyurethane (PU) adhesives. The PU adhesive containing only calcium carbonate showed similar thermal, mechanical, surface, and adhesion properties to those of the PU adhesive without a ller. The addition of 90 wt% fumed silica C 10 wt% calcium carbonate mixture to the PU adhesive produced a performance similar to or improved over that of the PU adhesive containing only fumed silica. The increase in the amount of natural calcium carbonate with respect to fumed silica in the ller mixture had a detrimental effect on the rheological and mechanical properties of the PU adhesives, although the surface and nal adhesion properties were not noticeably modi ed. The immediate adhesion (45 min after joint formation) was noticeably increased in the joints produced with the PU adhesives containing llers, mainly in those with a higher fumed silica content; a cohesive failure in the adhesive was produced in those joints and the mechanical and rheological properties of the PU adhesives determined the immediate adhesion. The failure in the joints peeled 72 h after joint formation was adhesional and the adhesion properties were mainly determined by the surface properties of the PU adhesives. All the adhesive joints showed a similar nal adhesion because they have similar surface properties.

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Three ethylene vinyl acetate (EVA) copolymers with different vinyl acetate (VA) contents (28-40 wt%) were mixed with rosin ester and polyterpene resin tacki ers in a 1 : 1 (weight/ weight) ratio. The rheological and thermal properties of the tacki ers were determined and the use of rheological measurements as a precise way to measure the softening point of the tacki ers is proposed. The glass transition temperature of the tacki ers was obtained from the second heating run, after the thermal history of the tacki ers was removed. The addition of the rosin ester to EVA produced a compatible mixture, whereas for the terpene resin a less compatible mixture was obtained. The increase in the VA amount decreased the crystallinity of EVA and both the storage and the loss moduli also decreased, but the peel strength and the immediate adhesion were increased. The immediate adhesion of EVA/ tacki er blends was affected by both the compatibilityand the rheologicalproperties of the blends. In fact, a relationship between the mechanical storage modulus (E 0 ) -obtained from DMTA experiments -of the adhesives and the immediate adhesion to thin rubber substrates was obtained. The adhesives containing the T tacki er showed higher moduli than those containing the G tacki er, and therefore higher peel strength values were obtained. An increase in the VA content increased the exibility of the adhesives and thus a decrease in peel strength was obtained.