Hysteresis

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Polyurethane elastomers having prolonged flex life and tires made therefrom
US 3980606

ABSTRACT
Polyurethane elastomers having prolonged flex life are prepared by reacting a diisocyanate with polypropylene glycol (PPG) or triol and poly(tetramethylene ether) glycol (PTEG). The diisocyanate may be reacted with each glycol separately or they may be mixed before the reaction. A smaller amount of the prepolymer obtained from the polypropylene glycol or triol is mixed with a larger amount of the prepolymer obtained from the poly(tetramethylene ether) glycol and the mixture is reacted with a hindered aromatic diamine. Elastomers cured from the resulting mixed polyurethane were found to have an exceptionally high flex life and are particularly useful in the production of products which undergo dynamic flexing, as in the preparation of pneumatic tires, particularly the sidewalls thereof, because of their exceptionally long flex life. Learn more.  

Low heat buildup polyurethane compositions and articles
US 4556703

ABSTRACT
A prepolymer curable with a hydroxyl or amine functional curative to form a polyurethane elastomer composition having low heat buildup characteristics is disclosed. Specifically, the polyurethane prepolymer has terminally reactive isocyanate groups and is prepared by reaction of polymeric diol with a stoichiometric excess of a mixture of the 2,6- and 2,4-isomers of tolylene diisocyanate, said mixture containing from about 50 to about 90 wt % of the 2,6-isomer. The invention also relates to a polyurethane elastomer composition comprising the aforementioned prepolymer and a curingly effective amount of a curative selected from the group consisting of aromatic diamines, hydroxy functional compounds, and mixtures thereof, and optionally, from about 0.01 to 1 part of catalyst per hundred parts of prepolymer. Also disclosed are articles of manufacture produced from the above composition, as well as compositions wherein the mixture contains 40 to 100 wt % of the 2,6-isomer. Learn more.

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