| 摘要 |
Runflat tires are generally made by including a stiff insert in the sidewall thereof. This insert should be as stiff as possible to help support the weight of the vehicle to which the tire is mounted in situations where there is a loss of air pressure. During periods of operation after loss of air pressure the stiff insert carries most of the load on the tire which leads to the generation of heat. Heat build-up can then lead to thermal degradation in the insert. A reduction in crosslink density and a change in the distribution of crosslink types is the result of this thermal degradation. This invention is based upon the discovery that thermal degradation in the inserts of runflat tires can be inhibited by including a bis-citraconimido compound therein as an antireversion agent. This invention more specifically discloses a pneumatic tire having at least one insert to provide the tire with runflat capability wherein the insert is comprised of a rubbery polymer and antireversion agent, such as pentaerythritol triacrylate, pentaerythritol tetraacrylate, N-N'-m phenylenediamaleimide, hexamethylene bis-thiosulfate disodium salt dihydrate, mixtures of zinc salts of aliphatic and aromatic carboxylic acids, alkylphenol disulfide, dioctylthiophosphate, caprolactam disulfide, 4-morpholinyl-2-benzothiazole disulfide, thiocarbamyl sulfenamide, 4,4'-dithiodimorpholine, mixtures of N-N'-m phenylenediamaleimide and tetrabenzylthiuram disulfide, and sulfur containing organosilicon compounds. |
