Multilayer dissolvable solid article containing coating composition and process for making the same
This present invention provides dissolvable solid articles comprising multiple layers of flexible, dissolvable, porous sheets, in which a coating composition is present on at least one internal surface of at least one sheet in said solid articles. The present invention also provides 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 first 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;
the dissolvable solid article has an outer surface;
a coating composition comprising a second surfactant 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; and
the second surfactant comprises a C12-C14 ethoxylated alcohol and the coating composition further comprises a perfume and dipropylene glycol.
2. The dissolvable solid article of claim 1 , wherein at least one of said two or more sheets comprises from about 5% to about 50%, 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 50,000 to about 400,000 Daltons; and
wherein said water-soluble polymer is a polyvinyl alcohol characterized by a degree of hydrolysis ranging from about 40% to about 100%.
3. The dissolvable solid article of claim 1 , wherein at least one of said two or more sheets comprises from about 50% to about 70%, of said first surfactant by total weight of said sheet; wherein said first surfactant is selected from the group consisting of a C 6 -C 20 linear alkylbenzene sulfonate, a C 6 -C 20 linear or branched alkylalkoxy sulfate having a weight average degree of alkoxylation ranging from about 0.5 to about 10, a C 6 -C 20 linear or branched alkyl sulfate, a C 6 -C 20 linear or branched alkylalkoxylated alcohol having a weight average degree of alkoxylation ranging from about 5 to about 15, and any combination thereof.
4. The dissolvable solid article of claim 1 , wherein said coating composition is a liquid having a viscosity from about 3 cps to about 5,000 cps, as measured at 20° C. and 1 s −1 .
5. The dissolvable solid article of claim 1 , wherein said coating composition further comprises a rheology modifier selected from the group consisting of: cellulose, a guar, polyethylene oxide, polypropylene oxide, polyethylene oxide/polypropylene oxide copolymers; polyvinylpyrrolidone, crosslinked polyvinylpyrrolidone, polyvinylalcohol, polyethyleneimine; sodium carbonate, sodium sulphate, silicon dioxide, water-swellable clays, gums, and any combination thereof.
6. The dissolvable solid article of claim 1 , wherein said coating composition further comprises an additional ingredient selected from the group consisting of a silicone, a softening agent, a bleaching agent, an enzyme, an anti-bac agent, an anti-oxidant, a brightener, a hueing dye, a polymer, a personal care active, and any combination thereof.
7. The dissolvable solid article of claim 1 , wherein said coating composition comprises less than 20%, of water by total weight of said coating composition.
8. The dissolvable solid article of claim 1 , wherein said coating composition is applied in an amount of about 10% to about 60%, by total weight of said dissolvable solid article.
9. The dissolvable solid article of claim 1 , wherein said coating composition is applied on one or more contacting surfaces of the sheets which are in a stack.
10. The dissolvable solid article of claim 1 , wherein said coating composition is applied on one or both contacting surfaces of any two adjacent sheets in a stack excluding the two outermost sheets.
11. The dissolvable solid article of claim 1 , wherein said coating composition is applied in a central region on each of an applied surface of the respective sheets, wherein the applied surface is a region that is spaced apart from the peripherals of the respective sheets by a distance that is at least 10%, of the maximum Dimension D.
12. The dissolvable solid article of claim 1 , wherein at least one of said two or more sheets comprises from about 11% to about 25%, of said water-soluble polymer by total weight of said sheet;
wherein said water-soluble polymer has a weight average molecular weight from about 80,000 to about 150,000 Daltons; and
wherein said water-soluble polymer is a polyvinyl alcohol characterized by a degree of hydrolysis ranging from about 65% to about 92%.
13. The dissolvable solid article of claim 1 , wherein at least one of said two or more sheets further comprises from about 0.00001% to about 1% of a bittering agent by total weight of said sheet.
14. The dissolvable solid article of claim 1 , wherein the ratio by weight of said second surfactant to said perfume is from about 1:50 to about 50:1.
15. The dissolvable solid article of claim 1 , wherein said coating composition comprises:
1) from about 10% to about 80%, of said second surfactant by total weight of said coating composition;
2) from about 1% to about 50%, of a solvent by total weight of said coating composition;
3) from about 1% to about 50%, of a rheology modifier by total weight of said coating composition; and
4) from about 10% to about 80%, of a perfume by total weight of said coating composition.
16. 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 first 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; wherein the dissolvable solid article has an outer surface; and
wherein a coating composition comprising a second surfactant, and 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; wherein the second surfactant comprises a C12-C14 ethoxylated alcohol and the coating composition further comprises a perfume and dipropylene glycol.
17. The dissolvable solid article of claim 16 , wherein the coating comprises from about 50% to about 65%, by weight of the coating, of the second surfactant, and from about 5% to about 15%, by weight of the coating composition, of dipropylene glycol.