1. Field of the Invention
The present invention relates to an acrylic elastomer composition and more particularly to an acrylic elastomer composition having distinguished vulcanization characteristics and scorch stability.
2. Description of Related Art
JP-A-50-132057 discloses a vulcanizable composition comprising a halogen-containing acrylic elastomer, a polyfunctional carboxylic acid, a quaternary ammonium salt and a halide ion acceptor, where it is stated that the halide ion acceptor includes well known metal oxy compounds as acid acceptors, such as alkali metal salts or non-alkali metal salts of monocarboxylic acid or organophosphoric acid; oxides, hydroxides or carbonates of non-alkali metals, metal; salts of inorganic acids; molecular sieves, etc.
The polyfunctional carboxylic acid includes, so far as its Examples are concerned, disodium azelate, dipotassium azelate, disodium sebacate, disodium trimethyladipate, bis(benzyltrimethylammonium) trimethyladipate, dipotassium dodecenylsuccinate, disodium or dipotassium of high molecular weight fatty acid dimer, etc., all of which are used in the form of disalt.
However, in case of using disodium azelate, both of the resulting primary vulcanization product and the secondary vulcanization product have considerably poor compression set characteristics, as shown in the results of Comparative Example 6 mentioned below in contrast to Example 4 using azelaic acid, and furthermore much prolonged vulcanization time is required with poor vulcanization characteristics. More particularly, secondary vulcanization is indispensable due to the relatively low crosslinking speed.