| 摘要 |
<p>A fluoroelastomer which is composed of vinylidene fluoride units and hexafluoropropylene units in a given proportion, contains occasionally tetrafluoroethylene units in a quantity below a specified value, contains also bound iodine, and has a multi-peak molecular weight distribution and a specified limiting viscosity number, and in which the ratio of the quantity of the low polymers to the limiting viscosity number and the ratio of the weight-average molecular weight to the number-average molecular weight are each within a specified range. Vulcanizing the elastomer causes the bound iodine to be released at the terminal and the polymers to be linked at the terminals through an unsaturated compound, forms a cross-linkage between the polymer chains with the use of a vulcanizer, and effects a sufficient vulcanization in the wide range from the low-molecule-weight to the high-molecular-weight components thereof to give a high-strength vulcanizate having an excellent balance between elongation and strength. The vulcanizate is improved in compression set by virtue of the increased cross-linking density and also in solvent and chemical resistances. Further it can provide an elastomer composition which is excellent in processability and post-curing properties, does not stick to rollers, and has a good working efficiency and an excellent productivity, thus being suitable as the material of fuel hoses and parts associated with an automotive engine.</p> |
