Patent ID: 8496861

Claim:
A method for making plastic fiber for application in concrete with largest grain diameters >4 mm, with an average diameter of 0.15 to 2 mm, corresponding to approximately 160 to 28′000 dtex (Decitex =grams per 10,000 running meters), the method comprising the steps of: using a co-extrusion process, forming a bi-component fiber having a central core and a casing around the central core, the central core and the casing containing different pure polymers or polymer mixtures, then stretching the co-extruded bi-component fiber by a factor of 5 to 15, and after the co-extruded bi-component fiber has been stretched, embossing a structured or grooved surface onto the co-extruded stretched bi-component fiber, the step of embossing the structured or grooved surface onto the co-extruded stretched bi-component fiber comprising performing the embossing such that a depth of the embossing is more than 10% of an average fiber diameter, and a maximal distances of structure tips within incorporated structures of the embossing in an axial direction lie in a region between 0.5 mm and 3 mm.