Thin film adhesive labels and methods of making thereof

Abstract

Thin film labels, systems, and methods of making and using thereof are described. The thin film systems contain a label and a carrier film, where the label contains an overprint layer, indicia, and an adhesive layer. The carrier film may be coated on one or both sides with a release liner. The adhesive layer can be any suitable adhesive, such as a pressure sensitive adhesive, a fluid activatable adhesive, a heat activated adhesive, or a contact activated adhesive. The label is formed by printed or coating one or more layers of precursor material on the carrier film using standard printers. Suitable precursor materials include, but are not limited to epoxys, solvent cast films, polyurethane dispersions, such as acrylic-urethane hybrid polymer dispersions and polyester-polyurethane dispersions. After the overprint layer dries or is cured, the indicia are printed onto the overprint layer, then the adhesive is coated on top of the indicia.

We claim: 
     
         1 . A group of thin film labels comprising a plurality of thin film labels on a carrier film, wherein each thin film label comprises an overprint layer, an indicia layer, and an adhesive layer, wherein the indicia layer is located between the overprint layer and the adhesive layer,
 wherein the overprint layer is in contact with one side of the carrier film, and   wherein the adhesion between the overprint layer and the carrier film is sufficiently strong to require a delamination peel force of greater than 0 g/mm and up to 5 g/mm to separate the overprint layer from the carrier film, and wherein each label is discontinuous with the other labels in the group.   
     
     
         2 . The group of  claim 1 , wherein the overprint layer is chemically resistant to isopropanol, methyl ethyl ketone, or both. 
     
     
         3 . The group of  claim 1 , wherein the overprint layer comprises a polymer selected from the group consisting of poly(acrylate) polymers, poly(alkacrylate) polymers, poly(urethane) polymers, poly(urethane acrylate) polymers, poly(ethoxylated acrylate) polymers, and saturated or unsaturated poly(urethane acrylate) polymers, or copolymers or combinations thereof. 
     
     
         4 . The group of  claim 3 , wherein the overprint layer comprises a polymer selected from the group consisting of poly(trimethylolpropane triacrylate); poly(neopentyl glycol propoxylate (2) diacrylate); poly(dipropylene glycol diacrylate); poly(triglycerol diacrylate); poly(hexanediol diacrylate); poly(ethoxylated (3) bisphenol A diacrylate); poly(trimethoxylolpropane ethoxy triacrylate); poly(ethoxylated (20) trimethylolpropane triacrylate); and poly(ethoxylated (15) trimethylolpropane triacrylate); or a copolymer or combination thereof. 
     
     
         5 . The group of  claim 1 , wherein the carrier film comprises a first side and a second side,
 wherein the first side comprises a first release layer, and   wherein when the system is in a set of two or more systems that are rolled or stacked, the adhesive layer is in contact with the first release layer of the system and/or the first release layer of an adjacent system in the set.   
     
     
         6 . The group of  claim 1 , wherein the carrier film comprises a first side and a second side, wherein the first side comprises a first release layer, wherein the second side comprises a second release layer, and wherein the second release layer is in contact with the overprint layer. 
     
     
         7 . The group of  claim 1 , wherein the adhesion between the overprint layer and the carrier film or the second release layer is sufficiently strong to require a delamination peel force ranging from 0.01 g/mm to 5 g/mm to separate the overprint layer from the carrier film or the second release layer. 
     
     
         8 . The group of  claim 1 , wherein the adhesion between the overprint layer and the carrier film or the second release layer is sufficiently strong to require a delamination peel force ranging from 0.1 g/mm to 5 g/mm to separate the overprint layer from the carrier film or the second release layer. 
     
     
         9 . The group of  claim 2 , wherein chemical resistance of the overprint layer is analyzed using a rub tester fitted with cheese cloth on the rubbing surface, wherein the overprint layer is saturated with methyl ethyl ketone or isopropyl alcohol, and wherein the overprint layer is mechanically rubbed for 50 double rubs. 
     
     
         10 . The group of  claim 1 , wherein the label has a thickness ranging from 0.1 mil to 1.5 mil. 
     
     
         11 . The group of  claim 1 , wherein the indicia layer in each of the thin film labels contains a portion of a complete indicia. 
     
     
         12 . The group of  claim 1 , wherein when the plurality of thin film labels is combined, they form a complete indicia. 
     
     
         13 . The group of  claim 5 , wherein the second side of the carrier film comprises a second release layer, wherein the second release layer is in contact with the overprint layer, and wherein the first release layer separates more easily from the adhesive layer than the second release layer separates from the overprint layer. 
     
     
         14 . A method of making the group of thin film labels of  claim 1 , comprising:
 (a) printing or coating onto the carrier film one or more UV-curable precursor compositions for forming the overprint layer;   (b) exposing the coating to ultra-violet (UV) radiation to cure the coating and form the overprint layer;   (c) printing an ink formulation one or more times on the overprint layer to form the indicia layer; and   (d) coating or printing one or more precursor formulations for forming the adhesive layer on top of the indicia layer and any exposed portion(s) of the overprint layer to form the adhesive layer.   
     
     
         15 . The method of  claim 14 , wherein the UV-curable precursor compositions comprise a photoinitiator and a UV-curable precursor material. 
     
     
         16 . The method of  claim 15 , wherein the UV-curable precursor material comprises monofunctional monomers, multifunctional monomers, or oligomers, or a combination thereof. 
     
     
         17 . The method of  claim 16 , wherein the UV-curable precursor material is a compound comprising one or more acrylate functionalities, one or more alkacrylate functionalities, or a combination thereof. 
     
     
         18 . The method of  claim 17 , wherein the UV-curable precursor material is trimethylolpropane triacrylate; neopentyl glycol propoxylate (2) diacrylate; dipropylene glycol diacrylate; triglycerol diacrylate; hexanediol diacrylate; ethoxylated (3) bisphenol A diacrylate; trimethoxylolpropane ethoxy triacrylate; ethoxylated (20) trimethylolpropane triacrylate; or ethoxylated (15) trimethylolpropane triacrylate; or a combination thereof. 
     
     
         19 . The method of  claim 15 , wherein the photoinitiator is blend of two or more photoinitiators. 
     
     
         20 . The method of  claim 15 , wherein the photoinitiator is dimethylhydroxyacetophenone (DMHA), 2,4,6-trimethylbenzoyldiphenylphosphone oxide (TPO), hydroxylcyclohexylphenylketone (CPK), 2,2-dimethoxy-2-phenylacetophenone (DMPA), benzophenone, 2,2-diethyloxyactetophenone, 2,4-diethylthiozanthone, isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide dimethylhydroxyacetophenone, ethyl(2,4,6-trimethylbenzoyl) phenylphosphinate, 2-phenylbenzophenone, methyl-o-benzoyl-benzoate, or methylbenzoylformate, or a combination thereof.