Coated scrap rubber particle production involves granulation of tires into crumb particles, mixing with pigment and then coating with binder incorporating polyurethane and reaction initiator

摘要

Scrap rubber, in particular old tires, are granulated(1) and the resulting crumb mixed(3) homogeneously with 0.1-20wt% of color pigments of at least one color. The color coated particles are then mixed(8) with 1-4.5wt% of a fluid binder mixture comprising a preheated two or more component polyurethane mixture and a thinned reaction initiator. The mixing chamber is moved(9,11) in such a way that the binder mixture cures, but coated particles do not bond together to form an agglomerate. Rubber particle diameter is 0.1-5mm, preferably 0.8-2mm. Mixing(3) of particles with color pigments is performed in a rotating intensive mixer for 1-20, preferably 5 minutes. The fluid binder mixture is prepared separately by mixing at least two components to form a thinned reaction initiator, combining(6) the latter with a further component to form an intermediate mixture and then adding another component to form the finished binder mixture. Warm air(7a) is passed through the mixing chamber during mixing(8) of particles and binder mixture. An independent claim is included for: a) a coated loose rubber particles obtained from scrap rubber, in particular scrap tires, which have a first layer of color pigments and second layer of binder mixture based on a multi-component polyurethane mixture and a thinned reaction initiator over the whole particle surface.