Multilayer dissolvable solid article containing solid particles for making the same
A dissolvable solid article which can include multiple layers of flexible, dissolvable, porous sheets, in which a coating composition including solid particles is present on at least one internal surface of at least one sheet in the solid articles and a process for making such solid articles.
1. A dissolvable solid article comprising two or more flexible, porous, dissolvable sheets, wherein each of said two or more sheets comprises a water-soluble polymer and a surfactant and is characterized by a Percent Open Cell Content of from about 80% to about 100% and an Overall Average Pore Size of from about 100 μm to about 2000 μm; and
a coating composition comprising a non-aqueous liquid carrier comprising perfume oil, silicone, fatty acid, or combination thereof; solid particles; and a thickening agent; wherein said composition comprises: a) from about 20% to about 80%, of said non-aqueous liquid carrier by total weight of said coating composition; b) from about 20% to about 60%, of said solid particles by total weight of said coating composition; c) from about 0.1% to about 30%, of said thickening agent by total weight of said coating composition; said solid particles comprise a bleaching agent, a bleach activator, or an anionic surfactant, said thickening agent comprises silica; and wherein said coating is present on at least one surface of at least one of said two or more sheets, provided that said coating composition is not on any of the outer surfaces of the dissolvable solid article.
2. The dissolvable solid article of claim 1 , wherein said non-aqueous liquid carrier comprises perfume oil.
3. The dissolvable solid article of claim 1 , wherein said non-aqueous liquid carrier further comprises a non-ionic surfactant comprising a C 6 -C 20 linear or branched alkylalkoxylated alcohol having a weight average degree of alkoxylation ranging from about 5 to about 15.
4. The dissolvable solid article of claim 1 , wherein said thickening agent further comprises clay, a polyacrylate thickener, a polyacrylamide thickener, an alginate, an ethoxylated cellulose, a hydroxy propyl cellulose, a hydroxy ethyl cellulose, or a combination thereof.
5. The dissolvable solid article of claim 1 , wherein said solid particles further comprise an oxidative dye compound, a pH modifier, a buffering agent, a radical scavenger, a chelant, a warming active, a color indicator, an enzyme, an effervescent system, or a combination thereof.
6. The dissolvable solid article of claim 5 , wherein said anionic surfactant comprises alkyl and alkyl ether sulfates, sulfated monoglycerides, sulfonated olefins, alkyl aryl sulfonates, primary or secondary alkane sulfonates, alkyl sulfosuccinates, acyl taurates, acyl isethionates, alkyl glycerylether sulfonate, sulfonated methyl esters, sulfonated fatty acids, alkyl phosphates, acyl glutamates, acyl sarcosinates, alkyl sulfoacetates, acylated peptides, alkyl ether carboxylates, acyl lactylates, anionic fluorosurfactants, sodium lauroyl glutamate, or a combination thereof;
wherein said enzyme comprises proteases, amylases, cellulases, lipases, xylogucanases, pectate lyases, mannanases, cutinases, or a combination thereof; and
wherein said effervescent system is an acid source comprising citric acid, malic acid, tartaric acid, fumaric acid, adipic acid, maleic acid, aspartic acid, glutaric acid, malonic acid, succinic acid, boric acid, benzoic acid, oleic acid, citramalic acid, 3-chetoglutaric acid, or any combination thereof, and an alkali source comprising a carbonate salt, a bicarbonate salt, a sesquicarbonate salt, or a combination thereof.
7. The dissolvable solid article of claim 1 , wherein said solid particles comprise C6-C20 linear alkylbenzene sulphonate surfactant.
8. The dissolvable solid article of claim 1 , wherein said solid particles comprise a bleaching agent selected from the group consisting of percarbonate salts, perborate salts, persulfate salts, or any combination thereof.
9. The dissolvable solid article of claim 1 , wherein said solid particles comprises a bleach activator.
10. The dissolvable solid article of claim 9 , wherein the bleach activator comprise tetraacetylethylenediamine, oxybenzene sulphonate, caprolactam; pentaacetate glucose, nitrile quaternary ammonium, imide bleach activator, or a combination thereof.
11. The dissolvable solid article of claim 1 , wherein said coating composition comprises:
1) from about 20% to about 60%, of said non-aqueous liquid carrier by total weight of said coating composition;
2) from about 30% to about 60%, of said solid particles by total weight of said coating composition; and
3) from about 0.1% to about 3%, of said thickening agent by total weight of said coating composition.
12. The dissolvable solid article of claim 1 , wherein at least one of said sheets comprises from about 9% to about 40%, of said water-soluble polymer by total weight of said sheet;
wherein said water-soluble polymer has a weight average molecular weight of from about 20,000 to about 150,000 Daltons; and
wherein said water-soluble polymer is a polyvinyl alcohol characterized by a degree of hydrolysis ranging from about 70% to about 90%.
13. The dissolvable solid article of claim 1 , wherein at least one of said sheets comprises from about 40% to about 80%, of said surfactant by total weight of said sheet;
wherein said surfactant comprises a C 6 -C 20 linear alkylbenzene sulfonate, a C 6 -C 20 linear or branched alkylalkoxy sulfates having a weight average degree of alkoxylation ranging from about 0.5 to about 10, a C 6 -C 20 linear or branched alkylalkoxylated alcohol having a weight average degree of alkoxylation ranging from about 5 to about 15, a C 6 -C 20 linear or branched alkyl sulfate, or a combination thereof.
14. The dissolvable solid article of claim 1 , wherein said two or more sheets comprises a first group of sheets and a second group of sheets in which the coating composition is present on at least one surface of at least one of said first group of sheets but not on any one surface of said second group of sheets.
15. The dissolvable solid article of claim 14 , wherein said coating composition comprises a bleaching agent selected from the group consisting of a percarbonate salt, a perborate salt, a persulfate salt, or a combination thereof; and
wherein each sheet within said second group of sheets comprises a bleach activator comprising tetraacetylethylenediamine, oxybenzene sulphonate, caprolactam; pentaacetate glucose, nitrile quaternary ammonium, imide bleach activator, or a combination thereof.
16. The dissolvable solid article according to claim 1 , wherein the coating composition comprises from about 0.15% to about 2%, of said thickening agent by total weight of said coating composition.
17. A process for preparing a dissolvable solid article according to claim 1 comprising:
providing the two or more flexible, porous, dissolvable sheets and the coating composition;
applying the coating composition on at least one surface of at least one sheet from said two or more sheets; and
arranging the two or more sheets into a stack to form the dissolvable solid article so that the coating composition is not on any of the outer surfaces of the stack.
18. The process of claim 17 , wherein said two or more flexible, porous, dissolvable sheets are provided by using the following steps:
a) preparing a wet pre-mixture comprising said water-soluble polymer and said surfactant;
b) aerating said wet pre-mixture to form an aerated wet pre-mixture;
c) forming said aerated wet pre-mixture into a sheet having opposing first and second sides; and
d) drying said formed sheet to make said two or more flexible, porous, dissolvable sheet.
19. The process of claim 18 , wherein step d) is conducted for a duration from about 10 min to about 120 min, 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.
20. The process of claim 19 , wherein the wet pre-mixture has a viscosity of from 1,000 cps to 25,000 cps measured at 40° C. and 1 s −1 , and/or the aerated wet pre-mixture has a density of from about 0.2 g/ml to about 0.6 g/ml.