Patent ID: 7319126

Claim:
A crosslinkable branched synthetic polyisoprene, having an apparent stress F/S 0 greater than or equal to 0.4 MPa at a relative elongation α of 150%, applied to a dumbbell-shaped test specimen (1) which consists of said crosslinkable polyisoprene and is obtained by: forming a plate of thickness E=2.5 mm consisting of said polyisoprene by pressure molding for 10 minutes at 110° C. in a mold between two polyester sheets, cooling the plate formed in said manner under pressure for a period of 16 hours, extracting the plate formed and cooled in said manner from said mold on completion of said period, cutting out said test specimen (1) from the plate extracted in said manner such that said test specimen (1) comprises two ends joined to one another by a shank of thickness E=2.5 mm, length L=26 mm and width W=6 mm, said test specimen (1) then being subjected, at the latest 1 hour after said extraction, to tension at a temperature of 23° C. and an atmospheric humidity of 50% by displacement at the constant speed of 100 mm/min of the mobile jaws of a tensile tester (2) relative to the fixed jaws of said tester, said jaws respectively holding said ends with an identical clamping pressure of 2 bar, where: α (%)=100×D/L (D being the measured displacement of said mobile jaws in mm), and F/S 0 (MPa)=tensile force F/initial cross-section S 0 (width×thickness in mm 2 ) of the test specimen(1).