Permeable pressure sensitive adhesive

1. A pressure sensitive adhesive composition for skin application comprising:

10-50% (w/w) based on a total adhesive composition of a polar part;

10-50% (w/w) based on a total adhesive composition of an apolar part; and

30-50% (w/w) based on a total adhesive composition of hydrocolloid(s);

wherein the polar part comprises polar polyethylene copolymer(s) and polypropylene oxide, and the apolar part comprises one of polyisobutylene, styrene block copolymer, and butyl rubber.

2. The pressure sensitive adhesive composition according to claim 1 , wherein the polar part comprises polypropylene oxide in a content of above 10% (w/w) of said polar part with a content of the polyethylene copolymer(s) at 10-50% (w/w) of said polar part, and the polar polyethylene copolymer has a melt flow index below 2 g/10 min (190° C./21.1N).

3. The pressure sensitive adhesive composition according to claim 1 , wherein the adhesive composition in continuous form exhibits a moisture vapour transmission rate of at least 400 g/m 2 /24 hours.

4. The pressure sensitive adhesive composition according to claim 1 , wherein the polar polyethylene copolymer is selected from the group consisting of ethylene vinyl acetate, ethylene vinyl acetate carbon monoxide, ethylene butyl acetate, ethylene vinyl alcohol, ethylene butyl acrylate, ethylene butyl acrylate carbon monoxide, and combinations thereof.

5. The pressure sensitive adhesive composition according to claim 4 , wherein the polar polyethylene copolymer is ethylene vinyl acetate.

6. The pressure sensitive adhesive composition according to claim 5 , wherein the ethylene vinyl acetate has a content of 40%-80% (w/w) vinyl acetate.

7. The pressure sensitive adhesive composition according to claim 1 , wherein the polar polyethylene copolymer(s) has a molecular weight of above 250,000 g/mol.

8. The pressure sensitive adhesive composition according to claim 1 , wherein the polar plasticizing oil is selected from the group of liquid rosin derivatives, aromatic olefin oligomers, vegetable and animal oils and derivatives thereof.

9. The pressure sensitive adhesive composition according to claim 1 , wherein a ratio of polar polyethylene copolymer and polypropylene oxide is between 1:1 and 1:4.

10. The pressure sensitive adhesive composition according to claim 1 , wherein the composition further comprises a polar polymer with a melt flow index >2 (190° C./21.1N).

11. The pressure sensitive adhesive composition according to claim 1 , wherein the composition further comprises a tackifier resin.

12. The pressure sensitive adhesive composition according to claim 1 , wherein the composition further comprises an apolar resin compatible with the apolar part of the adhesive.

13. The pressure sensitive adhesive composition according to claim 11 , wherein a content of the tackifier resin(s) is 0.1-20% (w/w) of the adhesive composition.

14. The pressure sensitive adhesive composition according to claim 1 , wherein the composition further comprises an additional plasticiser selected from the group of mineral oil, citrate oil, paraffin oil, phthalic acid esters, adepic acid esters, liquid resin and solid resin.

15. The pressure sensitive adhesive composition according to claim 1 , wherein the composition further comprises a polyethylene wax.

16. The pressure sensitive adhesive composition according to claim 1 , wherein the composition further comprised other ingredients selected from the group of antioxidants, stabilisers, fillers, pigments, flow modifiers, and active ingredients.

17. The pressure sensitive paste composition according to claim 1 , wherein the polyisobutylene has a molecular weight of below 100,000 g/mol.

18. The pressure sensitive adhesive composition according to claim 1 , wherein the styrene block copolymer is a styrene-isoprene-styrene block copolymer.

19. The pressure sensitive adhesive composition according to claim 1 , wherein the butyl rubber has an average molecular weight of 200,000 to 600,000 g/mol.

20. The pressure sensitive paste composition according to claim 1 , wherein the content of the polar part is 20-40% (w/w) of the total adhesive composition.

21. The pressure sensitive paste composition according to claim 1 , wherein the content of the apolar part is 20-40% (w/w) of the total adhesive composition.

22. The pressure sensitive adhesive composition according to claim 1 , wherein a ratio of the content of the polar part and the apolar part is between 1:4 and 4:1.

23. A layered adhesive construction comprising a backing layer and at least one layer of the pressure sensitive adhesive composition of claim 1 .

24. The layered adhesive construction according to claim 23 , wherein the construction further comprises at least one layer of a water absorbing adhesive.

25. The layered adhesive construction according to claim 23 , wherein the layer of the pressure sensitive adhesive composition of claim 1 is located for placement between a layer of a water absorbing adhesive and the skin.

26. A medical device comprising a the pressure sensitive adhesive composition of claim 1 and a backing layer.

27. The medical device according to claim 26 , wherein the backing layer is non-vapour permeable.

28. The medical device according to claim 26 , wherein the backing layer is water vapour permeable and has a moisture vapour transmission rate above 500 g/m 2 /24 h.

29. The medical device according to claim 26 wherein the medical device is one of a dressing, an ostomy appliance, a prosthesis, e.g. a breast prosthesis, a urine collecting device, a faecal management device, a measuring instrument or a therapeutic instrument, a medical tape, and a bandage.

30. The pressure sensitive adhesive composition according to claim 1 , wherein a ratio of the content of the polar part and the apolar part is between 2:3 and 3:2.