Process for providing an extended tubular article with a corrosion protection coating system having self-repairing properties

1. A process for improving the adhesion between an extended tubular article or a section thereof and a corrosion protecting system, the process comprising:

(a) applying a layer of an adhesive composition to a surface of the extended tubular article or a section thereof; and, subsequently,

(b) applying a corrosion protecting layer to the layer of the adhesive composition,

wherein the adhesive composition comprises a polyolefin blend, wherein the polyolefin blend comprises 30% to 100% by weight of a polyisobutene and 0% to 70% by weight of one or more olefin polymers, based on the total weight of the polyolefin blend, wherein the polyisobutene has the following properties (i) to (v):

(i) a glass transition temperature of lower than −40° C.;

(ii) a number average molecular weight M n of 1,300 to 1,000,000;

(iii) a molecular weight distribution M w /M n of between 1 to 10;

(iv) a surface tension of less than 40 mN/m at 20° C.; and

(v) a density between 0.90 to 0.95 g/cm 3 ;

wherein the corrosion protecting layer comprises a polyisobutene and 40 to 80% by weight of a filler material, based on the total weight of the corrosion protecting layer; and

wherein the adhesive composition either comprises 1 to 10% by weight of a filler, based on the total weight of the adhesive composition, or consists of the polyolefin blend.

2. The process according to claim 1 , wherein the polyisobutene has a number average molecular weight M n of 5,000 to 1,000,000.

3. The process according to claim 2 , wherein the polyisobutene has a number average molecular weight M n of 10,000 to 1,000,000.

4. The process according to claim 1 , wherein the polyisobutene has a Staudinger Index J o of 10 to 1,500 cm3/g as determined at 20° C.

5. The process according to claim 4 , wherein the polyisobutene has a Staudinger Index J o of 20 to 1,000 cm3/g as determined at 20° C.

6. The process according to claim 1 , wherein the olefin polymer has a glass transition temperature of lower than −20° C.

7. The process according to claim 6 , wherein the olefin polymer is selected from the group consisting of:

(a) a polymer comprising 50.0% to 99.9% by weight of isobutene and 0.1% to 50.0% of an optionally substituted, linear or branched C 2 -C 12 alkene or an optionally substituted, linear or branched C 2 -C 12 alkadiene, based on the total weight of the polymer;

(b) a polymer comprising 50.0% to 99.9% by weight of propene and 0.1% to 50.0% of a an optionally substituted, linear or branched C 2 -C 12 alkene, based on the total weight of the polymer;

(c) a polymer comprising 0.1% to 50.0% by weight of ethene and 50.0% to 99.9% of an optionally substituted, linear or branched C 2 -C 12 alkene, based on the total weight of the polymer;

(d) a polymer comprising 0.1% to 50.0% by weight of 2-methyl-1-pentene and 50.0% to 99.9% of an optionally substituted, linear or branched C 2 -C 12 alkene, based on the total weight of the polymer; and

(e) mixtures thereof.

8. The process according to claim 7 , wherein the olefin polymer is polybutene having a melt index of 0.2 to 300 g/min, a density of 0.90 to 0.95 g/cm 3 , and a melting point of 80° to 130° C.

9. The process according to claim 7 , wherein the olefin polymer is butyl rubber having a Mooney viscosity ML 1+8 of 25 to 75 and a level of unsaturation of 1.0 to 3.0 mol %.

10. The process according to claim 7 , wherein the olefin polymer is atactic polypropylene having a number average molecular weight M n of 1,000 to 3,000 and a weight average molecular weight M w of 100,000 to 200,000.

11. The process according to claim 7 , wherein the olefin polymer is poly(2-methyl-1-pentene), optionally having a melt index of 1 to 250 g/min, a softening point of 160° to 200° C., and a density of 0.82 to 0.85 g/cm 3 .

12. The process according to claim 6 , wherein the olefin polymer is uncrosslinked.

13. The process according to claim 1 , wherein the adhesive composition comprises a filler.

14. The process according to claim 13 , wherein the filler is a fumed silica.

15. The process according to claim 13 , wherein the adhesive composition comprises 1 to 10% by weight of the filler, based on the total weight of the adhesive composition.

16. The process according to claim 1 , wherein the extended tubular article is a pipe or pipeline.

17. The process according to claim 1 , wherein the extended tubular article is made of steel, concrete or both.

18. The process according to claim 1 , wherein the extended tubular article is pre-coated.

19. The process according to claim 18 , wherein the pre-coat comprises an epoxy resin.

20. The process according to claim 1 , wherein the extended tubular article is provided with a base layer.

21. The process according to claim 20 , wherein the base layer comprises a homopolymer or a copolymer of an optionally substituted, linear or branched C 2 -C 12 alkene.

22. The process according to claim 1 , wherein the corrosion protecting layer is heat shrinkable.

23. The process according to claim 22 , wherein the corrosion protecting layer comprises a shrink sleeve or a wrap-around sleeve or sheet.

24. The process according to claim 1 , wherein the corrosion protecting layer comprises a polyisobutene having a glass transition temperature of less than −20° C. and surface tension of less than 40 mM/m at 20° C. and a filler material.

25. The process according to claim 24 , wherein a film layer is applied to the corrosion protecting layer.

26. The process according to claim 25 , wherein the film layer comprises an olefinic polymer or copolymer.

27. The process according to claim 24 , wherein the corrosion protecting layer comprises a wrapping tape.

28. The process according to claim 27 , wherein the wrapping tape comprises a first layer comprising a film and a second layer comprising a composition comprising a polyisobutene having a glass transition temperature of less than −20° C. and surface tension of less than 40 mM/m at 20° C. and a filler material.

29. The process according to claim 28 , wherein the film comprises an olefinic polymer or copolymer.