Abstract: This invention has an object of enhancing the cold resistance of a heavy duty power transmission V-belt without impairing its durability at high temperatures, ensuring its sufficient power transmission capability and concurrently enhancing its permanent set resistance. To attain the object, the invention employs, for a rubber element of the belt, a rubber composition in which 20 to 40 parts by weight of a metal salt monomer of an organic acid and 5 to 35 parts by weight of short fibers are mixed into 100 parts by weight of a rubber component composed of EPDM and HNBR in their ratio of 55/45 to 75/25, the rubber hardness measured with a durometer Type D is 40 to 60, the value of t5 given by a Gehman torsion test is ?50° C. to ?35° C., and the amount of acetone extract from the rubber component is 9% or less.

Abstract: A process is described for encapsulating a solution of color reactants of color-reaction systems present in an aqueous emulsion accomplished by means of conventional microencapsulation processes, in which the color reactant is first dissolved in a solvent and a non-dissolver, which may insignificantly dissolve the color reactant, is mixed into the resulting solution in an amount that establishes a supersaturated solution while mixing at high speed, the supersaturated solution is emulsified immediately in the aqueous phase while mixing at high speed, and immediately thereupon the encapsulation is performed. A vegetable oil C1–C8 alkyl ester is used as the solvent. This process has economic and technological advantages. For example, it can be used to produce microcapsules that have an advantageous narrow monomodal particle distribution, which results in improved writing performance.