Water-soluble film having improved dissolution and stress properties, and packets made therefrom

Abstract

Disclosed is a pouch having at least one sealed compartment containing a first composition. At least one wall of the at least one sealed compartment is made from a water-soluble film having any suitable thickness. The water-soluble film comprises PVOH polymer such that when the film has a thickness of about 76 microns the film is characterized by a Dissolution Index of about 620 to about 920, or of about 665 to about 920, or about 710 to about 920; and a Stress Index of about 145 to about 626, or about 155 to about 480, or about 165 to about 325.

1 . A water-soluble film having any suitable thickness, the water-soluble film comprising:
 at least 50 wt. % of a water-soluble polyvinyl alcohol (PVOH) resin, the PVOH resin having an average viscosity in a range of about 13.5 cP to about 20 cP and a degree of hydrolysis in a range of about 84% to about 92%; and   the film further having no more than 30 wt. % of a PVOH polymer having an average viscosity less than about 11 cP;   the film further characterized by having a Dissolution Index in a range of about 620 to about 920 and a Stress Index in a range of about 145 to about 626 when the film has a thickness of about 76 microns,   wherein the film is thermoformable.   
     
     
         2 . The water-soluble film of  claim 1 , wherein the PVOH resin comprises a first PVOH polymer having a viscosity in a range of about 8 cP to about 40 cP and a second PVOH polymer having a viscosity in a range of about 10 cP to about 40 cP, wherein the viscosity of the first PVOH polymer is less than the viscosity of the second PVOH polymer. 
     
     
         3 . The water-soluble film of  claim 2 , wherein the first PVOH polymer has a viscosity in a range of about 10 cP to about 20 cP. 
     
     
         4 . The water-soluble film of  claim 3 , wherein the first PVOH polymer has a viscosity in a range of about 10 cP to about 15 cP. 
     
     
         5 . The water-soluble film of  claim 2 , wherein the second PVOH polymer has a viscosity in a range of about 20 cP to about 30 cP. 
     
     
         6 . The water-soluble film of  claim 5 , wherein the second PVOH polymer has a viscosity in a range of about 20 cP to about 25 cP. 
     
     
         7 . The water-soluble film of  claim 1  further comprising about 1 wt. % to about 40 wt. % of a plasticizer. 
     
     
         8 . The water-soluble film of  claim 7 , wherein the plasticizer comprises a material selected from the group consisting of glycerin, sorbitol, propylene glycol, 2-methyl-1,3-propanediol, and a mixture thereof. 
     
     
         9 . The water-soluble film of  claim 7 , wherein the film comprises about 15 wt. % to about 35 wt. % of the plasticizer. 
     
     
         10 . The water-soluble film of  claim 1  further comprising a residual moisture content in a range of about 4 wt. % to about 10 wt. %. 
     
     
         11 . The water-soluble film of  claim 1 , wherein the Dissolution Index is in a range about 665 to about 920. 
     
     
         12 . The water-soluble film of  claim 11 , wherein the Dissolution Index is in a range of about 710 to about 920. 
     
     
         13 . The water-soluble film of  claim 1 , wherein the Stress Index is in a range of about 155 to about 480. 
     
     
         14 . The water-soluble film of  claim 13 , wherein the Stress Index is in a range of about 165 to about 325. 
     
     
         15 . The water-soluble film of  claim 1  further characterized by a Burst Strength Test value of greater than about 20 seconds when the film has a thickness of about 76 microns. 
     
     
         16 . The water-soluble film of  claim 15 , wherein the Burst Strength Test value is greater than about 30 seconds. 
     
     
         17 . The water-soluble film of  claim 1 , wherein the resin is characterized by a Resin Selection Index value in a range of 0.255 to 0.315. 
     
     
         18 . A water-soluble film comprising:
 at least 50 wt. % of a PVOH resin, the resin having an average viscosity in a range of about 13.5 cP to about 20 cP and a degree of hydrolysis in a range of about 84% to about 90%; the resin comprising a blend of first and second PVOH polymers, the first PVOH polymer having a viscosity in a range of about 8 cP to about 40 cP, the second PVOH polymer having a viscosity in a range of about 10 cP to about 40 cP, and the viscosity of the first PVOH polymer being less than the viscosity of the second PVOH polymer;   about 10 wt. % to about 40 wt. % of a plasticizer;   a residual moisture content of at least 4 wt. %; and   the film further having no more than 30 wt. % of a PVOH polymer having an average viscosity less than about 11 cP;   the film further characterized by a Dissolution Index of about 620 to about 920 and a Stress Index of about 145 to about 626 when the film has a thickness of about 76 microns.   
     
     
         19 . The water-soluble film of  claim 18 , wherein the residual moisture content is in a range of about 4 wt. % to about 10 wt. %. 
     
     
         20 . A water-soluble film comprising:
 at least 50 wt. % of a PVOH resin characterized by a Resin Selection Index value in a range of 0.255 to 0.315, the resin comprising a blend of first and second PVOH polymers, the first PVOH polymer having a viscosity in a range of about 8 cP to about 40 cP, the second PVOH polymer having a viscosity in a range of about 10 cP to about 40 cP, and the viscosity of the first PVOH polymer being less than the viscosity of the second PVOH polymer;   about 10 wt. % to about 40 wt. % of a plasticizer; and   the film further having no more than 30 wt. % of a PVOH polymer having an average viscosity less than about 11 cP;   the film further characterized by a Dissolution Index of about 620 to about 920 and a Stress Index of about 145 to about 626 when the film has a thickness of about 76 microns.   
     
     
         21 . The water-soluble film of  claim 20 , wherein the Resin Selection Index value is in a range of 0.260 to 0.310. 
     
     
         22 . The water-soluble film of  claim 21 , wherein the Resin Selection Index value is in a range of 0.265 to 0.305. 
     
     
         23 . The water-soluble film of  claim 22 , wherein the Resin Selection Index value is in a range of 0.270 to 0.300. 
     
     
         24 . A pouch comprising the water-soluble film of  claim 1 . 
     
     
         25 . The pouch of  claim 24  comprising two or more compartments.