Wall covering and method of producing the same
A wall covering, a method of producing it and a method of covering a wall. The wall covering comprises a planar substrate, such as a nonwoven base substrate, having a front, and a back facing opposite the front. There is a barrier layer on the back of the substrate and an adhesive layer superimposed on the barrier layer. The adhesive layer comprises a first polymer component, a second polymer component, the first polymer component being a non crosslinked polymer and said second polymer component being a crosslinked polymer exhibiting properties of superabsorbency. The adhesive exhibits when exposed to water, a strength sufficient for binding to a wall substrate and a glide resistance low enough for allowing repositioning of the wall cover by sliding the wallcover on the wall without having to lift it up over a period of time of at least 5 minutes.
1. A wall covering comprising:
a planar substrate having a front, and a back facing opposite the front;
a barrier layer on the back; and
an adhesive layer, having a thickness, on the barrier layer;
wherein
the adhesive layer comprises a first polymer component and a second polymer component, the first polymer component being a non-crosslinked polymer and said second polymer component being a crosslinked polymer exhibiting properties of superabsorbency,
said crosslinked polymer being a reversibly swellable polymer, which has the ability to absorb about 20 to 500 times its weight when exposed to liquid water, and wherein the barrier layer is permeable to water vapor and exhibits a permeability.
2. The wall covering according to claim 1 , wherein a weight ratio between the first polymer component and the second polymer component is 1:100 to 100:1.
3. The wall covering according to claim 1 , wherein the first polymer component comprises a water soluble polymer.
4. The wall covering according to claim 1 , wherein the adhesive layer is formed from a water borne adhesive having a viscosity at room temperature of less than 2000 cps at 25% solids.
5. The wall covering according to claim 1 , wherein the substrate is selected from the group consisting of nonwoven substrates, papers, and boards.
6. The wall covering according to claim 5 , wherein the second polymer component is located in discrete portions of the adhesive layer, the discrete portions capable of absorbing water and of swelling to a diameter greater than a thickness of other portions of the adhesive layer which do not include the discrete portions, upon wetting of the adhesive layer.
7. The wall covering according to claim 1 , wherein the thickness of the adhesive layer is 0.01 to 2.0 mm.
8. The wall covering according to claim 1 , wherein the second polymer component is selected from polymers which are soluble in water in a non-crosslinked state.
9. The wall covering according to claim 1 , wherein said second polymer is crosslinked with a crosslinking agent capable of complexing with functional groups of the second polymer component.
10. The wall covering according to claim 1 , wherein said second polymer component is crosslinked with a crosslinking agent selected from crosslinking agents comprising a metal.
11. The wall covering according to claim 1 , wherein the barrier layer is impermeable to water but permeable to vapor.
12. The wall covering according to claim 1 , wherein the barrier layer comprises a crosslinked polymer and 5 to 70% by weight of a pigment selected from pigments having an aspect ratio of 60 to 200.
13. The wall covering according to claim 1 , wherein the barrier layer comprises pigments selected from the group consisting of clay, talc, and combinations thereof.
14. The wall covering according to claim 1 , wherein the barrier layer has a COBB60 value in a range of 3-130 gsm determined using T441 om-90.
15. The wall covering according to claim 1 , wherein the substrate comprises fibres selected from the group consisting of natural fibres, synthetic fibres, and mixtures thereof.
16. The wall covering according to claim 1 ,
wherein the planar substrate comprises a porous substrate sheet.
17. The wall covering according to claim 1 , wherein the dry adhesive layer has an essentially non-tacky surface feel when dry.
18. The wall covering according to claim 1 , wherein a weight ratio between the first polymer component and the second polymer component is 1:50 to 50:1.
19. The wall covering according to claim 1 , wherein a weight ratio between the first polymer component and the second polymer component is 1:10 to 10:1.
20. The wall covering according to claim 1 , wherein the substrate is selected from the group consisting of nonwoven substrates, papers, and boards, and wherein the substrate is in a form of a sheet or web.
21. The wall covering according to claim 1 , wherein the thickness of the adhesive layer is 0.05 to 1 mm.
22. The wall covering according to claim 1 , wherein the first polymer component is selected from water soluble polymers which contain ionic or ionizable functional groups or functional groups capable of hydrogen bonding, or combinations thereof.
23. The wall covering according to claim 1 , wherein the first polymer component comprises a non-crosslinked polyalkenoic acid and the second polymer component comprises a crosslinked polyalkenoic acid.
24. The wall covering according to claim 1 , wherein the second polymer component is selected from polymers which contain ionic or ionizable functional groups.
25. The wall covering according to claim 24 , wherein the ionic or ionizable functional groups comprise a member selected from the group consisting of metal carboxylates, carboxylic acids, ammonium halides, amino groups, and combinations thereof.
26. The wall covering according to claim 1 , wherein the second polymer component comprises a crosslinked polyalkenoic acids.
27. The wall covering according to claim 26 , wherein the second polymer component is crosslinked with a crosslinking agent capable of complexing with functional groups of the polyalkenoic acid.
28. The wall covering according to claim 1 , wherein the second polymer component is crosslinked with a crosslinking agent selected from crosslinking agents comprising a transition metal.
29. The wall covering according to claim 1 , wherein said second polymer component is crosslinked with a crosslinking agent selected from crosslinking agents comprising zirconium, zinc, chromium, iron, and mixtures thereof.
30. The wall covering according to claim 1 , wherein the barrier layer is impermeable to water but permeable to vapor, and wherein the barrier layer exhibits a permeability, characterized by a Tappi TM 161 Gurley Air Porosity value of 1-150 L/min/100 cm 2 .
31. The wall covering according to claim 1 , wherein the barrier layer is impermeable to water but permeable to vapor, and wherein the barrier layer exhibits a permeability, characterized by a Tappi TM 161 Gurley Air Porosity value of 8-20 L/min/100 cm 2 .
32. The wall covering according to claim 1 , wherein the barrier layer comprises pigments selected from the group of kaolin clay, engineered clay, talc, and combinations thereof.
33. The wall covering according to claim 1 , wherein the barrier layer has a COBB60 value in a range of 15-50 gsm, determined using T441 om-90.
34. The wall covering according to claim 1 , wherein the second polymer component exhibiting properties of superabsorbency has the ability to absorb about 50 to 150 times its weight when exposed to liquid water.
35. The wall covering according to claim 1 , wherein the second polymer component exhibiting properties of superabsorbency has the ability to absorb about 100±10 times its weight when exposed to liquid water.