| 简介 |
Crosslinkable synthetic polyisoprene (I) with an elongation of 150% under a tensile stress of at least 0.4 MPa, as measured by a defined test, is new. Crosslinkable synthetic polyisoprene (I) with an elongation of 150% under a tensile stress of at least 0.4 MPa, as measured by a defined test, is new. The test comprises making a 2.5 mm thick plate of (I) by compression molding at 110degreesC for 10 minutes in a mold between two sheets of polyester, cooling the plate under pressure for 16 hours, removing the plate from the mold, cutting the plate into a dumbell shape whose ends are connected by a shaft with a thickness of 2.5 mm, a length of 26 mm and a width of 6 mm, gripping the resulting test piece with a clamping pressure of 2 bar between the jaws of an Instron 4501 (RTM) tensile testing machine within 1 hour of removal from the mold, subjecting the test piece to traction at 23degreesC and 50% relative humidity with a jaw displacement speed of 100 mm/minute, and calculating the elongation as 100 times the jaw displacement divided by the initial shaft length and the tensile stress as the tractive force divided by the initial cross-sectional area of the test piece. An Independent claim is also included for production of (I) by polymerizing isoprene in bulk or in an inert hydrocarbon solvent using a catalyst comprising a conjugated diene monomer, a rare earth metal organophosphate suspended in a (cyclo)alkane solvent, a di- or trialkylaluminum alkylating agent and an alkyl aluminum halide halogen donor, and branching the product with a Lewis acid. |
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