| 摘要 |
This invention relates to a foamable blend comprising an in-reactor polymer blend comprising: (a) a first propylene polymer component comprising 90 to 100 wt % propylene and from 0 to less than 10 wt % comonomer, said first propylene component having a Tm of 120° C. or more; and (b) a second propylene polymer component comprising from 30 to 90 wt % propylene and 70 to 10 wt % comonomer, said second propylene polymer having an Mw of 30,000 g/mol or more, and said second propylene-containing polymer having a crystallinity different by at least 5% from the first polymer, wherein the polymer blend, prior to combination with a foaming agent, has: (i) a Tm of at least 120° C.; (ii) a MFR of 10 dg/min or more; (iii) a tensile strength of at least 8 MPa; (iv) an elongation at break of at least 200%, and (v) a ratio of elongational viscosity at break to linear viscosity of 5 or more when the elongational viscosity is measured at a strain rate of 1 sec−1 and temperature of 180° C.; and where when the blend is foamed with a foaming agent, the foamed article has a density of 800 kg/m3 or less.
|
