Medical articles and methods of making using immiscible material

1. A medical article comprising:

a PSA layer comprising acid-functional groups or basic-functional groups, wherein the PSA includes at least 0.42 mmoles acidic- or basic-functional groups per gram PSA; and

an MVTR-modifying material that is basic when the PSA comprises acidic-functional groups or is acidic when the PSA comprises basic-functional groups;

wherein the MVTR-modifying material is immiscible with the PSA, and reacts with the functional groups of the PSA upon contact to form a poly-salt in the presence of fluid; and

wherein the PSA comprises a hydrophilic polymer component.

2. The medical article of claim 1 , wherein the PSA comprises a functional polymer, and wherein said polymer is prepared from at least 3 wt-% acidic- or basic-functional monomers, based on the total weight of the PSA.

3. The medical article of claim 1 , wherein the MVTR-modifying material is disposed on a surface of the PSA layer.

4. The medical article of claim 3 , wherein the MVTR-modifying material is pattern coated onto the surface of the PSA layer.

5. The medical article of claim 1 further comprising a second PSA layer, wherein the MVTR-modifying material is disposed between the two PSA layers.

6. The medical article claim 1 , wherein the MVTR-modifying material is incorporated within a scaffold that is in contact with the PSA layer.

7. The medical article of any one of claim 1 , wherein the medical article comprises a backing and the MVTR-modifying material is disposed between the PSA layer and the backing.

8. The medical article of claim 1 further comprising a pH-altering layer, wherein the MVTR-modifying material is disposed between the PSA layer and the pH-altering layer, and wherein the pH-altering layer comprises a pH-altering material.

9. The medical article of claim 1 further comprising:

a carrier film in contact with the PSA layer;

an absorbent pad disposed between the carrier film and the adhesive layer; and

a backing disposed between a support layer and the PSA layer, wherein the medical article is wound dressing.

10. The medical article of claim 1 , wherein the hydrophilic polymer component is reactive with monomers of the PSA.

11. The medical article of claim 10 , wherein the reactive hydrophilic polymer component comprises a vinyl group copolymerizable with the monomers of the PSA.

12. The medical article of claim 11 , wherein the reactive hydrophilic polymer component comprises a hydrophilic macromolecular monomer represented by the general Formula I:

X—Y—Z

wherein:

X is a vinyl group copolymerizable with the PSA monomers;

Y is a divalent linking group; and

Z is a monovalent polymeric moiety.

13. The medical article of claim 12 , wherein:

X is of the general Formula II:

wherein R a is a hydrogen atom or a methyl group;

Y is a divalent carbonyl group; and

Z is a monovalent polyether of the general Formula III:

—W—OR b

wherein:

R b is hydrogen, lower alkyl, phenyl, or substituted phenyl; and

W is a divalent poly(lower alkylene oxide) group containing 2 to about 250 repeating alkoxy units.

14. The medical article of claim 1 , wherein the hydrophilic polymer component is present in an amount of no greater than 30 weight percent, based on the total weight of the PSA.

15. The medical article of claim 1 , wherein the hydrophilic polymer component is nonreactive with adhesive monomers of the PSA.

16. The medical article of claim 15 , wherein the nonreactive hydrophilic polymer component has a molecular weight of greater than 1000.

17. The medical article of claim 15 , wherein the nonreactive hydrophilic polymer component comprises a poly(alkylene oxide) copolymer.

18. The medical article of claim 1 , wherein the PSA comprises hydrophobic and hydrophilic polymer components in a ratio of at least 1.5:1.

19. The medical article of claim 1 , wherein the combined weight percent of the functional groups and hydrophilic polymer component in the PSA is at least 15% by weight of the PSA.

20. A wound dressing comprising:

a backing having a first major surface and a second major surface;

a PSA layer disposed on at least a portion of the first major surface of the backing; wherein the PSA comprises acid-functional groups or basic-functional groups, wherein the PSA includes at least 0.42 mmoles acidic- or basic-functional groups per gram PSA; and

an MVTR-modifying layer proximate the PSA layer; wherein the MVTR-modifying layer comprises an MVTR-modifying material that is basic when the PSA comprises acidic-functional groups, or is acidic when the PSA comprises basic-functional groups;

wherein the MVTR-modifying material is immiscible with the PSA, and reacts with the functional groups to form a poly-salt upon contact in the presence of fluid; and

wherein the PSA comprises a hydrophilic polymer component.