Patent ID: 7678839
Filing Date: 2010-03-16
Classification: C08J

Abstract:
1. Expanded beads comprising cell walls which define a plurality of cells and which comprise a base resin comprising a polypropylene resin, each of said beads having a through hole extending therein from one end to the other end, said beads having a maximum diameter D wherein the ratio L wherein D (a) ten beads are arbitrarily sampled; (b) each sampled bead is cut by a plane perpendicular to a straight line connecting the one end and the other end of the through hole at the center of said straight line to give an annular cross-section having an outer circumference and an inner circumference; (c) the annular cross-section is displayed or photographed using a microscope; (d) on the cross-section thus displayed or photographed, a first straight line is drawn such that the first straight line intersects the outer circumference at two intersection points D (e) the distance Dn (f) a second straight line perpendicular to the first straight line is drawn such that the second straight line intersects the outer circumference at two intersection points d (g) a circle C (h) a number Nn (i) two circles C (j) numbers of intersection points between the first straight line and cell walls located on the circle C (k) an average cell diameter Ln (l) an average cell diameter Ln (m) maximum diameter Hn (n) D (o) L (p) L (q) H