Opacifying label
View Patent ↗A multilayer label having an opacifying layer coated onto the back side of a paper facestock is provided. The opacifying layer prevents the paper from losing opacity when the label is subjected to wet conditions.
1. A label composite comprising:
a paper substrate having an upper print surface and a lower surface;
an opacifying layer covering the lower surface of the paper substrate, the opacifying layer formed from a coating composition comprising (a) at least one water-dispersible aliphatic polyether-polyurethane; (b) at least one wax; and (c) about 0.3% to about 2% by weight of water dispersible silica particles; and
an adhesive layer adhered to the opacifying layer;
wherein the paper substrate is an outermost layer of the label composite; and
wherein the silica particles have a surface area greater than 500 m 2 /g.
2. The label composite of claim 1 wherein the upper print surface is surface treated to improve its printability.
3. The label composite of claim 1 wherein the aliphatic polyether polyurethane comprises the reaction product of an aliphatic polyisocyanate component and a polyether polyol component.
4. The label composite of claim 1 wherein the at least one wax comprises an anionic aqueous emulsion of wax.
5. The label composite of claim 1 wherein the coating composition further comprises a pigment.
6. The label composite of claim 5 wherein the pigment comprises TiO 2 .
7. The label composite of claim 1 wherein the amount of the at least one water-dispersible aliphatic polyether-polyurethane in the coating composition is in the range of about 70% to about 98% by weight; and wherein the amount of the at least one wax in the coating composition is in the range of about 1% to about 10% by weight.
8. The label composite of claim 1 wherein the adhesive comprises a pressure sensitive adhesive.
9. The label composite of claim 1 wherein the adhesive comprises a heat activatable adhesive.
10. The label composite of claim 1 wherein the at least one wax comprises a blend of paraffin and polyethylene wax.
11. The label composite of claim 1 wherein the opacifying layer is opaque.
12. The label composite of claim 1 wherein the opacifying layer consists of (a) the at least one water-dispersible aliphatic polyether-polyurethane; (b) the at least one wax; and (c) the water dispersible silica particles.
13. The label composite of claim 1 wherein the opacifying layer further comprises a white pigment.
14. The label composite of claim 1 wherein the water dispersible silica particles range in size from about 2 to about 15 microns.
15. A label composite consisting of:
a paper substrate having an upper print surface and a lower surface;
an opacifying layer covering the lower surface of the paper substrate, the opacifying layer formed from a coating composition comprising (a) at least one water-dispersible aliphatic polyether-polyurethane; (b) at least one wax; and (c) about 0.3% to about 2% by weight of water dispersible silica particles; and
an adhesive layer adhered to the opacifying layer;
wherein the silica particles have a surface area greater than 500 m 2 /g.
16. The label composite of claim 15 , wherein the coating composition comprises (a) about 70% to about 98% by weight of the at least one water-dispersible aliphatic polyether-polyurethane; (b) about 1% to about 10% by weight of the at least one wax; and (c) about 0.3% to about 2% by weight of water dispersible silica particles.
17. The label composite of claim 16 , wherein the amount of the water dispersible silica particles in the coating composition is in the range of about 0.4% to about 1% by weight.
18. The label composite of claim 15 , wherein the amount of the water dispersible silica particles in the coating composition is in the range of about 0.4% to about 1% by weight.
19. A label composite comprising:
a paper substrate having an upper print surface and a lower surface;
an opacifying layer covering the lower surface of the paper substrate, the opacifying layer formed from a coating composition comprising (a) about 70% to about 98% by weight of at least one water-dispersible aliphatic polyether-polyurethane; (b) about 1% to about 10% by weight of at least one wax; and (c) about 0.3% to about 2% by weight of water dispersible silica particles;
an adhesive layer adhered to the opacifying layer;
wherein the silica particles have a surface area greater than 500 m 2 /g.
20. The label composite of claim 19 , wherein the amount of the water dispersible silica particles in the coating composition is in the range of about 0.4% to about 1% by weight.