Patent ID: 8669322
Filing Date: 2014-03-11
Classification: B29B,B29C,B29K,C08J,C08L,C09J

Abstract:
1. A process for manufacturing an adhesive by means of extrusion, the adhesive comprising: i) at least one degraded polypropylene (co)polymer and ii) at least one additional additive, the process comprising the following steps: a) providing a first extrusion section with one or more temperature zones and a second extrusion section with one or more temperature zones; b) feeding a polypropylene (co)polymer into the first extrusion section and subsequently thermomechanically degrading the polypropylene (co)polymer in the presence of at least one radical donor in the first extrusion section by shear stress to manufacture a degraded polypropylene (co)polymer, wherein the temperature of the first extrusion section, at least in one zone, is above the softening point of the polypropylene (co)polymer; c) transferring the degraded polypropylene (co)polymer from the first extrusion section into the second extrusion section, wherein the content of the radical donor in the degraded polypropylene (co)polymer on entry into the second extrusion section is less than 0.01 wt % based on the total amount of the degraded polypropylene (co)polymer; d) feeding at least one additive into the second extrusion section and subsequently blending the additive with the degraded polypropylene (co)polymer under shear stress to manufacture the adhesive; wherein the melt viscosity determined at 200° C. of the degraded polypropylene (co)polymer on entry into the second extrusion section is less than 70% of the melt viscosity determined at 200° C. of the polypropylene (co)polymer, the highest temperature in the second extrusion section is less than the highest temperature in the first extrusion section, and the degraded polypropylene (co)polymer is transferred in the molten state from the first extrusion section into the second extrusion section.