Patent ID: 7288131
Filing Date: 2007-10-30
Classification: B01D,B01J,C04B,F01N,Y10T

Abstract:
1. A porous honeycomb structure comprising: a plurality of partition walls containing cordierite as a main component and comprising a porous ceramic having a porosity of 55 to 75% and an average pore diameter of 15 to 35 μm, characterized in that pores of the partition walls have a pore distribution represented by the following condition formula (1): “in the above condition formula (1), Lr means an average developed length ratio obtained by the following equation (2), and P means a porosity obtained from a total pore volume measured by a mercury press-in type porosimeter, assuming that a true specific gravity of cordierite is 2.52 g/cc:” “in the above equation (2), Lo means an average developed length (an average value of lengths including the surfaces of the pores opened in the partition wall surfaces) obtained when using a surface roughness measuring instrument and checking optional ten places on the partition wall surfaces every 4 mm (straight line length ignoring presence of the pores opened in the partition wall surfaces) along the partition wall surfaces with a stylus, and Lr means the average developed length ratio,” and wherein the pores of the partition walls have a tomographic pore distribution represented by the following condition formula (3) in a partition wall thickness direction: “in the above condition formula (3), X denotes an average value of a primary component amplitude spectrum (F) and a secondary component amplitude spectrum (S) obtained from the following equations (4) and (5), and P means a porosity obtained from the total pore volume measured by the mercury press-in type porosimeter, assuming that the true specific gravity of cordierite is 2.52 g/cc:” “in the above equation (4), F denotes the primary component amplitude spectrum assuming k=1 in the following conversion equation (6), and X “in the equation (5), S denotes the secondary component amplitude spectrum assuming k=2 in the following conversion equation (6), and X “in the conversion equation (6), X