Patent ID: 9421575
Filing Date: 2016-08-23
CPC Classification: B05D,B32B,B41M,B65D,Y10T

Claim Text:
1. A method for manufacturing a water soluble film (WSF) carrying at least one security element incorporated in at least one layer of said WSF, said method comprising the steps of: forming a mixture by adding one or more security elements into at least one batch mixer containing a batch solution of the WSF, the batch solution having a temperature ranging from 10° C. to 95° C.; mixing the mixture thoroughly; feeding the mixture to primary or subsequent casting heads for further processing for forming a WSF having said one or more security element embedded in at least one layer of said WSF; unwinding a liner from an unwinder and casting said mixture on said liner to form a first WSF layer on the liner; drying the first film layer in a primary dryer section, wherein the temperature in the primary dryer section ranges from 50° C. to 250° C.; casting a second layer of said mixture on top of said first WSF layer to form a second WSF layer; drying the second WSF layer in a secondary dryer section wherein the temperature in the secondary dryer section ranges from 50° C. to 250° C.; and stripping said liner immediately or after a self-curing, ageing period ranging from 1 to 720 hours; wherein the method further includes adding an overt security element to the film by one of the following steps: mixing at least one security element in printing ink and printing letters or graphics on said WSF, wherein said printing ink comprises said at least one security element of said WSF; imprinting or imparting at least one security element on the WSF, said imprinting or imparting step being selected from the group consisting of a hot stamping foil method and an adhesive transfer method; or incorporating at least one security element in the WSF by printing said at least one security element on said WSF by a method selected from the group consisting of ink jet, flexo, gravure, and web offset.