Fluid activatable adhesive for glue-free, liner-free, labels for glass and plastic substrates and methods of use thereof
View Patent ↗Methods for applying a liner-free, or liner-less label, to a substrate, particularly glass or plastic (e.g., polyethylene terephthalate) substrates, are described herein. The method includes applying an adhesive composition, such as a polymeric coating, to a label face sheet, activating the adhesive composition with an activating fluid, and contacting the label to the substrate. The activating fluid is preferably a mixture of water and one or more organic solvents, such as low molecular weight alcohols.
1. A method for applying a liner-free label to a substrate, wherein the label comprises a non-tacky polymeric coating on a face sheet, the method comprising:
activating the polymeric coating with an activating fluid comprising water and one or more organic solvents to form a tacky coating, and
contacting the label to the substrate,
wherein the polymeric coating comprises one or more alkaline soluble polymers selected from the group consisting of styrene-maleic anhydride resins, esters of styrene-maleic anhydride resins, styrene-maleic anhydride amic acid resins, styrene-maleic anhydride imide resins, ammonium and alkali metal salts of styrene-maleic anhydride resins, and combinations thereof and one or more emulsion polymers,
wherein the alkaline soluble polymer is water-insoluble at neutral pH.
2. The method of claim 1 , wherein the emulsion polymer comprises a styrene-acrylic polymer.
3. The method of claim 1 , wherein the substrate is glass.
4. The method of claim 1 , wherein the substrate is wood or manufactured wood.
5. The method of claim 1 , wherein the substrate is polyethylene terephthalate.
6. The method of claim 1 , wherein the face sheet is printed or printable paper.
7. The method of claim 1 , wherein the face sheet is a printed or printable polymeric film.
8. The method of claim 1 , wherein the one or more organic solvents are one or more low boiling alcohols.
9. The method of claim 8 , wherein the activation fluid composition comprises 5% to 70% by weight of one or more low boiling alcohol(s).
10. The method of claim 9 , wherein the activation fluid composition comprises 10% to 30% by weight of one or more low boiling alcohol(s).
11. The method of claim 8 , wherein at least one low boiling alcohol is n-propanol or isopropanol.
12. The method of claim 1 , wherein the label has greater than 70% paper tear after 2 minutes.
13. The method of claim 12 , wherein the label has greater than 80% paper tear after 2 minutes.
14. The method of claim 13 , wherein the label has greater than 90% paper tear after 2 minutes.
15. The method of claim 1 , wherein the label exhibits no blocking after 90 seconds at 60 psi and 48° C.
16. The method of claim 1 , wherein the label exhibits no label drop-off after 72 hours immersed in ice water.
17. The method of claim 1 , wherein the label exhibits complete label drop-off after soaking in 0.5% to 5% sodium hydroxide solution at 65° C. to 75° C. for less than 5 minutes.
18. The method of claim 1 , wherein the label exhibits no label drop-off after 72 hours immersed in ice water and has complete label drop-off after soaking in 0.5% to 5% sodium hydroxide solution at 65° C. to 75° C. for less than 5 minutes.
19. The method of claim 1 wherein the alkaline soluble polymer comprises styrene-maleic anhydride resins.
20. The method of claim 1 , wherein the face sheet has a moisture vapor transmission rate of at least about 160 g/m 2 /24 hr.