Polyurethane composition having improved tear strength and process for preparation thereof
AssigneeBridgestone Tire Company Limited
InventorsYoji Watabe, Michio Ishii, Yutaka Iseda
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Abstract
A polyurethane composition having high tear strength has been produced by mixing homogeneously 20 to 50 parts by weight of finely divided acidic silica particles, 100 parts by weight of isocyanate-terminated prepolymer and appropriate parts of curative, and curing the mixture in a manner well known in the prior art, where the ratio (l/d) of average chain distance (l) between adjacent crosslinking points of the cured polyurethane chains to average size (d) of finely divided silica particles is in the range of from 2.5 to 20.
Claims16
A polyurethane composition for the preparation of articles having a high tear strength, comprising proportionally 100 parts by weight of prepolymer having terminal isocyanate groups, 20 to 50 parts by weight of finely divided acidic silica particles having a pH value of from 3 to 7 and appropriate parts of curative, the number average molecular weight of said prepolymer ranging from 1,000 to 5,000, the ratio (l/d) being such that the average distance (l) between adjacent crosslinking points of the cured polyurethane chains to average size (d) of the acidic silica particles ranges from 2.5 to 20.
Dependencies are inferred from the claim text.