Natural rubber
A cup lump natural rubber devoid of impurities with a size of greater than 0.5 mm and having a plasticity retention index of greater than 80 is provided. The use of such a natural rubber in a line for manufacturing a semi-finished product based on natural rubber makes it possible to ensure an improved compromise of performances which are the productivity of a line for manufacturing semi-finished products and the quality of the semi-finished products resulting from this production line.
1. A cup lump natural rubber, the cup lump natural rubber being devoid of impurities with a size of greater than 0.5 mm, and the cup lump natural rubber having a plasticity retention index of greater than 80.
2. The cup lump natural rubber according to claim 1 having a plasticity retention index of greater than or equal to 85.
3. The cup lump natural rubber according to claim 1 having a weight content of impurities of less than 0.12%.
4. The cup lump natural rubber according to claim 1 having a weight content of impurities of less than 0.05%.
5. The cup lump natural rubber according to claim 1 , wherein the cup lump natural rubber has a water content of less than 0.8% by weight.
6. The cup lump natural rubber according to claim 1 having a weight content of nitrogen of less than 0.4%.
7. The cup lump natural rubber according to claim 1 having a weight content of nitrogen of less than or equal to 0.3%.
8. The cup lump natural rubber according to claim 1 , wherein the cup lump natural rubber is devoid of impurities with a size of greater than 0.1 mm.
9. The cup lump natural rubber according to claim 1 , wherein the cup lump natural rubber is a stabilized natural rubber.
10. The cup lump natural rubber according to claim 9 , wherein the cup lump natural rubber is a natural rubber stabilized by a viscosity stabilizer selected from the group consisting of the compounds of formula XNH 2 and the salts of the compounds of formula XNH 2 , X representing a hydroxyl group or a C 1 -C 4 hydroxyalkyl group.
11. The cup lump natural rubber according to claim 10 , in which the viscosity stabilizer is hydroxylamine sulfate or hydroxylamine sulfate neutralized with sodium hydroxide.
12. The cup lump natural rubber according to claim 1 , wherein the cup lump natural rubber has a weight-average molar mass of greater than 1,000,000 g/mol.
13. A rubber composition comprising the natural rubber defined in claim 1 .
14. The rubber composition according to claim 13 , further comprising a reinforcing filler.
15. A semi-finished product comprising the rubber composition defined in claim 14 .
16. A tire comprising the rubber composition defined in claim 14 .
17. The cup lump natural rubber according to claim 11 , wherein the viscosity stabilizer is hydroxylamine sulfate.
18. A tire comprising the semi-finished product defined in claim 15 .