Dispersions of fibres in rubber

Abstract

Polymer-fibre mixtures with improved homogeniety of dispersion of fibres throughout the polymer matrix are prepared from fibres prior mixed or coated with a plasticizer which is compatible with both the fibre and the polymer matrix. Then the plasticizer-fibre combination can be mixed into the polymer matrix, using standard polymer mixing equipment and for reasonable lengths of time, to produce a mixture in which agglomerations of fibres are very materially reduced. A preferred fibre is a fibrillated aramid fibre, dispersion of which in polymers has previously caused particular difficulties. Suitable polymers include hydrocarbon elastomers such as SBR, for use with which an aromatic mineral oil is a preferred plasticizer, and oil-resistant NBR elastomers, for use with which an ester plasticizer such as dioctyl phthalate is preferred.

Dependencies are inferred from the claim text.