| abstract |
Provided are a flexible, porous, dissolvable solid sheet article and a process for preparing the said sheet article. The process comprises: a) preparing a wet pre-mixture comprising a water-soluble polymer and a surfactant and having a viscosity of from 1,000 cps to 25,000 cps measured at 40℃ and 1 s -1; b) aerating said wet pre-mixture to form an aerated wet pre-mixture having a density of from 0.05 to 0.5 g/ml; c) forming said aerated wet pre-mixture into a sheet having opposing first and second sides; and d) drying said formed sheet for a drying time of from 1 minute to 60 minutes at a temperature from 70℃ to 200℃ along a heating direction that forms a temperature gradient decreasing from the first side to the second side of said formed sheet, wherein said heating direction is substantially opposite to the gravitational direction for more than half of the drying time. The said solid sheet article comprises a top region adjacent to said top surface, a bottom region adjacent to said bottom surface, and a middle region therebetween; wherein said top, middle and bottom regions have the same thickness, and each of said top, middle and bottom regions is characterized by an Average Pore Size; and wherein the ratio of Average Pore Size in said bottom region over that in said top region is from 0.6 to 1.5. |