Abstract: A laminate for honeycomb structures comprised of two outside layers having good surface adhesion and a tough core layer, said core constituting from 50 to 70% by weight of the laminate and containing from about 60 to 80% by weight of poly(m-phenylene isophthalamide) fibrids and each outside layer constituting from 15 to 25% by weight of the laminate and containing about 60 to 70% by weight of floc.

Abstract: A high strength fibrid-floc sheet is made of a floc which can be carbon, aramid or glass. The fibrids are made from the following units: ##STR1## where n is 4 or 5; X is from 0.03 to 0.30 and Ar is a radical selected from 3,4'-oxydiphenylene, 4,4'-oxydiphenylene, 4,4'-sulfonyldiphenylene, 1,3-phenylene, 1-methyl-2,4-phenylene, and mixtures of such radicals with each other or mixtures of such radicals with up to 50 mol percent of 1,4-phenylene radicals based on the mixtures of radicals.

Abstract: Flash expansion of moist multi-layered boards wherein each layer comprises aramid floc bonded by aramid fibrid results in high strength, low density aramid boards.

Abstract: High temperature resistant pressboard having a density of 0.70 to 0.90 g/cc, a calculated void volume of 31 to 49, percent by volume of said pressboard and a smoothness of 80 to 250 microinches MD range and 90 to 260 microinches is disclosed. The pressboard is prepared by wet laying an aqueous dispersion of polyaramid fibrids and floc to form a waterleaf building up layers to form a wet lap which is dried and then pressed at 270.degree. C. to 520.degree. C. rising a press with a predetermined minimum opening to form the desired smooth low density pressboard.

Abstract: A process for making a wet-laid, elongate, nonwoven flexible sheet having an additive distributed in a predetermined cross-directional pattern includes providing two synthetic fibrous stocks containing the additive in a concentration higher in one stock than in the other stock. The stocks are supplied to a paper machine having a headbox for depositing the stocks on a wire to form a wet sheet with the stocks being introduced into the headbox from a plurality of cross-directional positions equally spaced-apart along the headbox with a generally equal amount of solids being introduced at each position and with the stock with the higher concentration being introduced in higher quantity than the other stock at least at one cross-directional position so that the additive is distributed in the predetermined cross-directional pattern.

Abstract: A process for making a high heat resistant oil-impregnatable insulating board, having a dielectric constant less than 2.7, made from bleached polytetrafluoroethylene floc and aromatic polyamide fibrids and the resulting insulating board are disclosed.