| 摘要 |
<p>A rubber composition for use in annular packer elements for blowout preventers is provided which comprises from about 45 to about 55 weight percent of an acrylonitrile-butadiene copolymer; from about 10 to about 15 weight percent of a first admixture further comprising a major amount of colloidal silica and minor effective amounts of coupling agent, curative, lubricant, dispersant, activator and antiscorching agent; from about 30 to about 40 weight percent of a second admixture further comprising a major amount of carbon black and minor effective amounts of a plasticizer, antioxidant and antiozonant; and minor effective amounts of tetraethyl thiuram disulfide and benzothiazyl disulfide.</p> |
