E.i. Dupont De Nemours and Company

Edmund A Merriman

Achim Amma

Mikhail R Levit

Jill A Conley

Kevin A Mulcahy

Lenard Oscar Lundblad

The invention concerns a paper comprising (a) 40 to 70 parts by weight of polypyridobisimidazole fiber, polypyridobisimidazole pulp, or mixtures thereof and (b) 30 to 60 parts by weight of friction modifiers, structural resins, wet-strength resins, processing aids, fillers, and mixtures thereof; the parts by weight being based on the total amount of a) and b) in the paper.

Friction papers comprising PIPD fiber

The invention concerns a paper comprising polypyridobisimidazole fibers, where the apparent density of the paper is from 0.1 to 0.5 g/cmand the tensile strength of the paper in N/cm is at least 0.00057X*Y, where X is the volume portion of polypyridobisimidazole in the total solids of the paper in % and Y is basis weight of the paper in g/m.

Paper comprising PIPD pulp and process for making same

The invention concerns a process for making a fibrillated polypyridobisimidazole floc comprising the steps of: cutting polypyridobisimidazole filaments to an average cut length of from about 0.5 to 10 mm; and applying energy to the polypyridobisimidazole filaments to produce a fibrillated floc having essentially the same average cut length after the application of energy as before the application of energy; where the fibrillated floc having a Canadian Standard Freeness (CSF), when dispersed in water by itself, of from about 400 to 750 ml.

Fibrillated polypyridobisimidazole floc

The present invention relates to meta- and para-aramid pulp for use as reinforcement material in products such as seals and friction materials. The pulp comprises (a) fibril free meta-aramid particles, (b) irregularly shaped, para-aramid fibrous structures, and (c) water, whereby the para-aramid fibrous structures contact and are wrapped partially around at least some of the meta-aramid particles. The invention further relates to processes for making such aramid pulp.

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Midlothian, VA, United States of America

Edmund A Merriman