Above is an image from US Patent No. 12,018,232 B

US Patent No. 12,018,232 B2 (Carl David MacNamara, HongSing Tan, Robert Wayne Glenn, Jr., Wenhu Pang, Kejing Du, Yuxiang Liu); The Procter & Gamble Company has been awarded a new patent for a solid format product.

The dissolvable solid article is comprised of two or more flexible, porous, dissolvable sheets comprised a water-soluble polymer and a surfactant. It is characterized by a Percent Open Cell Content of from 80-100% and an overall average pore size of 100-2000 μm; and a coating composition comprising a non-aqueous liquid carrier, solid particles, and a thickening agent. The composition comprises 20- 80%  of the non-aqueous liquid carrier by total weight of the coating composition and 20- 60%of said solid particles by total weight of said coating composition; and from 0.1%-5% of thickening agent by total weight of said coating composition.

The non-aqueous liquid carrier comprises a non-ionic surfactant, the solid particles comprise a bleaching agent, a bleach activator, or an anionic surfactant. The thickening agent comprises silica. The coating is present on at least one surface of at least one of said two or more sheets, provided that the coating composition is not on any of the outer surfaces of the dissolvable solid article.

Additional Patent Details

The coating composition comprising solid particles dispersed in a non-aqueous liquid carrier applied on one or both contacting surfaces of adjacent layers of the multilayer flexible, dissolvable, porous sheets to provide a multi-layer article with improved performance, according to the P&G patent file.

According to the patent literature, the inventors found that solid particles are often incompatible with the non-aqueous liquid carrier. The solid particles tend to aggregate and/or sediment. In some worse cases, phase separation occurs. To solve this problem, the present inventors developed a coating composition comprising a non-aqueous liquid carrier, a thickening agent, and solid particles. Particularly, the coating composition can comprise a nonionic surfactant as a non-aqueous liquid carrier, a thickening agent, and solid particles. In some examples, the thickening agent may be selected from the group consisting of silica, clays, polyacrylate thickeners, polyacrylamide thickeners, xanthan thickeners, guar gum, alginates ethoxylated cellulose, hydroxy propyl cellulose, hydroxy ethyl cellulose, and any combinations thereof.

Further, the inventors found the coating composition may have significantly improved stability. Additionally, the coating composition may provide additional benefits including but not limited to improved stability of active ingredients, improved leakage, improved loading capability, and improved process feasibility. According to the patent, the inventors found that the stability of bleaching agents added as the solid particles in the coating composition is significantly improved.