Process for making flexible, porous, dissolvable solid sheet articles with improved pore structures
AssigneeThe Procter & Gamble Company
InventorsHongsing TAN, Robert Wayne GLENN, JR., Carl David MAC NAMARA, Todd Ryan THOMPSON, Jason Allen STAMPER, John Philip HECHT, Xu HUANG, Ruizhi PEI, Paolo Efrain PALACIO MANCHENO, Toshiyuki OKADA
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Abstract
This provides an improved process for making a flexible, porous, dissolvable solid sheet article with improved pore structures.
Claims20
A process for preparing a sheet article, comprising the steps of:
- a) preparing a wet pre-mixture comprising a water-soluble polymer and a surfactant and having a viscosity of from about 1.0 Pa·s to about 25 Pa·s measured at 40° C. and 1 s−1;
- b) aerating the wet pre-mixture to form an aerated wet pre-mixture having a density of from about 0.05 to about 0.5 g/ml;
- c) forming the aerated wet pre-mixture into a sheet having opposing first and second sides;
- and
- d) drying the formed sheet for a drying time of from about 1 minute to about 60 minutes at a temperature from about 70° C. to about 200° C. along a heating direction that forms a temperature gradient decreasing from the first side to the second side of the formed sheet, wherein the heating direction is substantially opposite to the gravitational direction for more than half of the drying time.
The process of claim 1, wherein the wet pre-mixture further comprises a plasticizer.
The process of claim 9, wherein the heated surface is a planar surface.
The process of claim 11, wherein the rotary drum dryer has an outer diameter ranging from about 0.5 meters to about 10 meters.
A process for preparing a flexible, porous, dissolvable solid sheet article, comprising the steps of:
- a) preparing a wet pre-mixture comprising a water-soluble polymer and a surfactant;
- b) aerating the wet pre-mixture to form an aerated wet pre-mixture;
- c) forming the aerated wet pre-mixture into a sheet having opposing first and second sides;
- and
- d) drying the formed sheet along a heating direction that forms a temperature gradient decreasing from the first side to the second side of the formed sheet to form the flexible, porous, dissolvable solid sheet article comprising:
- i) a thickness ranging from about 0.5 mm to about 4 mm;
- ii) a Percent Open Cell Content of from 80% to less than 100%;
- and
- iii) an Overall Average Pore Size of from 100 μm to 2000 μm;
- wherein the solid sheet article comprises opposing top and bottom surfaces, the top surface comprises a Surface Average Pore Diameter that is greater than 100 μm;
- wherein the solid sheet article comprises a top region adjacent to the top surface, a bottom region adjacent to the bottom surface, and a middle region therebetween;
- wherein the top, middle, and bottom regions have the same thickness, and each of the top, middle and bottom regions is characterized by an Average Pore Size;
- and wherein the ratio of Average Pore Size in the bottom region over that in the top region is from about 0.6 to about 1.5.
Dependencies are inferred from the claim text.