| 摘要 |
<p>It is disclosed rigid materials such as sheets, boards or tubes made of expanded polypropylene, which have a uniform specific gravity d comprised between about 4.1 x 10<-><6> and about 8.1 x 10<-><6> Newton/mm<3>, a crystallization temperature comprised between about 115 DEG C and about 135 DEG C and a flexural modulus Mf expressed in Newton/mm<3> such that the ratio Mf:d is comprised between about 1.5 x 10<8> and 1.7 x 10<8>mm.</p> |
