The invention discloses constant
viscosity natural rubber and a preparation method thereof, and belongs to the technical field of
natural rubber processing. The rubber is 50.00-65.00 in
Mooney viscosity, is more than or equal to 60% in
plasticity retention percentage, higher than or equal to 14 Mpa in tensile strength, and more than or equal to 700% in elongation at break. The constant
viscosity natural rubber is prepared by adding more than or equal to 2.5% of a
hydroxylamine constant
viscosity solution and more than or equal to 8.0% of a hydrazine
hydrate solution in fresh latex. The preparation method of the constant viscosity natural rubber comprises the following processes of purification, constant viscosity treatment, solidification and curing,
dehydration and
impurity removal, and
drying, and comprises the following steps: at first, performing the
impurity removal on the fresh latex, adding more than or equal to 2.5% of the
hydroxylamine constant
viscosity solution and more than or equal to 8.0% of the hydrazine
hydrate solution according to the dry rubber amount, and mixing for not less than 20 min; then, mixing the diluted latex with an acid at the volume ratio of (576-626):1 and enabling the mixture to flow and enter into a groove, and
drying till the
water content is less than or equal to 0.8% after latex coagulum is subjected to
thinning, flotation, crumpling, pelleting and spraying. The constant viscosity natural rubber is stable in
Mooney viscosity, high in consistency of
sizing materials, excellent in performance, simple in production process, strong in interchangeability, and environment-friendly, and has a relatively high popularization value.