High modulus polyethylene fiber bundles as reinforcement for brittle matrices

DETAILED DESCRIPTION The present invention comprises the use of bundles of parallel or slightly twisted high modulus polyethylene fibers as reinforcement in composites wherein the matrix is a brittle material such as cement, concrete, plaster of Paris or the like.
A yarn made up of individual filaments, with a modulus in excess of 300 grams per denier, is initially passed through high pressure nip rolls to deform the individual filaments and to form a loosely adhering unitary mass or bundle of filaments.
This mas is then chopped into short lengths for use as fibrous reinforcement in composites.
This process results in short lengths of fibers wherein the bundle configuration is substantially maintained.
In a preferred embodiment, the yarn is twisted prior to being passed through the nip rolls.
The bundles of the present invention are particularly useful as reinforcement when brittle matrices are employed in forming thin architectural panels such as cladding panels and surface-bonded masonry, and are also useful for reinforcing asbestos/concrete piping.