The present invention is directed to a low-density substrate, which has an optimized pore volume distribution. The optimized pore volume distribution allows the substrate to hold at least 50 percent of its cumulative volume within pores with a radius size of about 110 to 250 microns. The optimized pore...http://www.google.es/patents/US7696109?utm_source=gb-gplus-sharePatente US7696109 - Low-density cleaning substrate
