Abstract: The joint boot having excellent cold resistance is obtained by compounding the cross-linking components (a), (b) and (c) with chlorinated polyethylene having a chlorine content of 31 to 34% by weight and molding the resulting compound under thermal conditions.(a) A mercaptotriazine compound,(b) at least one compound selected from the group consisting of amines having a boiling point of not lower than 110.degree. C., organic acid salts of the amines or addition products thereof, diarylguanidine, condensation products of aniline and aldehydes, and 2-benzothiazylsulfenamides of primary or secondary amines, and(c) a metal compound as an acid acceptor.

Abstract: In an accumulator in which a peripheral edge of a bladder dividing the interior of a shell into a gas chamber and a liquid chamber is attached to the shell, the radius of curvature of an inner wall of the shell defining the gas chamber is larger than that of an inner wall of the shell defining the liquid chamber. This construction ensures that the diameter of the bladder can be relatively increased, the deflection of the bladder with a variation in pressure in the gas chamber and in the liquid chamber can be increased, and the radius of curvature of a curved portion of the peripheral edge of the bladder can be increased, there by contributing to an overall improvement in the durability of the bladder.

Abstract: If a member made of rubber containing carbon black and a member made of aluminium alloy come into contact with each other under existence of an electrolytic solution, corrosion of the aluminium alloy member would proceed. Such corrosion of the aluminium alloy member can be suppressed by selecting a surface resistivity (surface electric resistivity) of the rubber member at 10.sup.6 .OMEGA. or higher, and more preferably 10.sup.7 .omega. or higher.

Abstract: A mechanical seal for a fluid pump wherein a driven ring is mounted in the pump casing and a seat ring is mounted on the pump vane. The two rings have opposed, radial faces for effecting the mechanical seal. The face on the seat ring is of a smaller width in the radial direction than the face of the driven ring so that any axial misalignment of the driven ring relative to the vane shaft does not effect the area of engagement on the two faces that form the seal, that is, the annular engagement area on the driven ring remains constant and coextensive with the engaging face of the seat ring.