Patent ID: 8444817

Claim:
A process for making a fibrillated thermoset and polyareneazole pulp for use as reinforcement material, comprising: (a) combining pulp ingredients including: (1) thermoset fiber that is capable of being fibrillated and having an average length of no more than 10 cm and being 60 to 97 weight percent of the total solids in the ingredients; (2) rigid rod polyareneazole fiber having an average length of no more than 10 cm and being 3 to 40 weight percent of the total solids in the ingredients; and (3) water being 95 to 99 weight percent of the total ingredients; (b) mixing the ingredients to a substantially uniform slurry; (c) co-refining the slurry by simultaneously: (1) fibrillating, cutting and masticating the fibrillated thermoset fiber and the polyareneazole fiber to irregularly shaped fibrillated fibrous structures with stalks and fibrils; and (2) dispersing all solids such that the refined slurry is substantially uniform; and (d) removing water from the refined slurry, thereby producing a fibrillated thermoset and polyareneazole pulp with the fibrillated thermoset and the polyareneazole fibrous structures having an average maximum dimension of no more than 5 mm, a length-weighted average length of no more than 1.3 mm, and the fibrillated thermoset fibrils and/or stalks are substantially entangled with the polyareneazole fibrils and/or stalks.