RELEASE FILM HAVING A THIN RELEASE COATING

Abstract

The invention relates to a method for producing a release film by coating a carrier film using a release coating, wherein the method comprises the steps of: (a) providing the carrier film, wherein the carrier film has a first surface side and a second surface side; wherein the carrier film is preferably structured; (b) providing a coating composition which has a solvent component, preferably comprising ethyl acetate, propyl acetate, butyl acetate, and/or n-propanol, and a silicone system curable by UV radiation; (c) coating at least part of the first surface side of the carrier film provided in step (a) using the coating composition provided in step (b); (d) evaporating at least a part of the solvent component; and (e) irradiating at least part of the first surface side of the carrier film coated in step (c) using UV radiation to cure the silicone system.

Claims

1. A release film comprising (i) a carrier film comprising optionally a first sealing layer (a); a layer (b), which is based on polyolefin, wherein the polyolefin is selected from the group consisting of olefin homopolymers or copolymers of α,ß-unsaturated olefins having 2 to 10 carbon atoms; and optionally a second sealing layer (c); and (ii) a release coating, which has a basis weight of at most 0.7 g/m.sup.2; wherein the carrier film has a first surface side and a second surface side; wherein the first surface side of the carrier film is at least partially coated using the release coating; and wherein the release film has a total layer thickness of at most 25 μm.

2. The release film according to claim 1, wherein the polyolefin is selected from the group consisting of polyethylene, polypropylene, polybutylene, polyisobutylene, polyhexene, polyoctene, copolymers and/or mixtures of at least two of the polymers mentioned.

3. The release film according to claim 1 or 2, wherein the olefin homopolymer or copolymer is an ethylene homopolymer or an ethylene copolymer.

4. The release film according to claim 3, wherein the ethylene homopolymer or copolymer is selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).

5. The release film according to any one of the preceding claims, wherein the polyolefin comprises a mixture of an ethylene homopolymer or copolymer and a propylene homopolymer or copolymer.

6. The release film according to any one of the preceding claims, wherein the polyolefin comprises a mixture of 51 to 85 wt. % of an ethylene homopolymer or copolymer having a density in the range of 0.91 to 0.97 g/cm.sup.3; and 15 to 49 wt. % of a propylene homopolymer or copolymer; each based on the total weight of the mixture.

7. The release film according to any one of the preceding claims, wherein release coating has a basis weight of at most 0.65 g/m.sup.2; preferably at most 0.60 g/m.sup.2, more preferably at most 0.55 g/m.sup.2, even more preferably at most 0.50 g/m.sup.2, most preferably at most 0.45 g/m.sup.2, and in particular at most 0.40 g/m.sup.2; preferably at most 0.35 g/m.sup.2, more preferably at most 0.30 g/m.sup.2, even more preferably at most 0.25 g/m.sup.2, most preferably at most 0.20 g/m.sup.2.

8. The release film according to any one of the preceding claims, which has a total layer thickness of at least 10 μm.

9. The release film according to any one of the preceding claims, wherein the optionally provided first sealing layer (a) and/or the optionally provided second sealing layer (c) are each independently based on polyolefins, wherein the polyolefin is selected from the group consisting of olefin homopolymers or copolymers of α,ß-unsaturated olefins having 2 to 10 carbon atoms; and an ethylene-vinyl acetate copolymer.

10. The release film according to any one of the preceding claims, wherein the optionally provided first sealing layer (a) and/or the optionally provided second sealing layer (c) are each independently based on an ethylene-vinyl acetate polymer.

11. The release film according to any one of the preceding claims, wherein the optionally provided first sealing layer (a) and/or the optionally provided second sealing layer (c) are each independently based on polyolefin, wherein the polyolefin is selected from the group consisting of olefin homopolymers or copolymers of α,β-unsaturated olefins having 2 to 10 carbon atoms.

12. The release film according to claim 11, wherein the polyolefin is selected from the group consisting of polyethylene, polypropylene, polybutylene, polyisobutylene, polyhexene, polyoctene, copolymers and/or mixtures of at least two of the polymers mentioned.

13. The release film according to claim 11 or 12, wherein the olefin homopolymer or copolymer is an ethylene homopolymer or an ethylene copolymer.

14. The release film according to claim 13, wherein the ethylene homopolymer or copolymer is selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).

15. The release film according to any one of the preceding claims, wherein the release coating directly adjoins with the carrier film.

16. The release film according to any one of the preceding claims, which has a total layer thickness of at least 5.0 μm; preferably at least 6.0 μm, more preferably at least 7.0 μm, even more preferably at least 8.0 μm, most preferably at least 9.0 μm, and in particular at least 10 μm.

17. The release film according to any one of the preceding claims, which has a total layer thickness in the range of 5.0 μm to 50 μm; preferably in the range of 10±5.0 μm, or 12.5±5.0 μm, or 15±5.0 μm, or 17.5±5.0 μm, or 20±5.0 μm.

18. The release film according to any one of the preceding claims, wherein the second surface side of the release film is uncoated.

19. The release film according to any one of the preceding claims, which consists of the carrier film and the release coating.

20. The release film according to any one of the preceding claims, wherein the first surface side and optionally the second surface side are preferably each coated independently of one another by at least 10%; preferably at least 20%, preferably at least 30%, preferably at least 40%, preferably at least 50%, preferably at least 60%, more preferably at least 70%, even more preferably at least 80%, most preferably at least 90%, and in particular completely (100%).

21. The release film according to any one of the preceding claims, wherein the carrier film is smooth.

22. The release film according to any one of the preceding claims, wherein the carrier film is structured.

23. The release film according to any one of the preceding claims, wherein the carrier film is embossed.

24. The release film according to any one of the preceding claims, wherein the first surface side of the carrier film is non-planar.

25. The release film according to any one of the preceding claims, wherein the first surface side of the carrier liner has an embossed structure on at least part of its surface.

26. The release film according to any one of the preceding claims, wherein first surface side and the second surface side of the carrier film each have an embossed structure on at least part of their surface.

27. The release film according to claim 25 or 26, wherein the embossed structure has a regular pattern.

28. The release film according to any one of the preceding claims, wherein the first surface side of the carrier film has embossed protrusions.

29. The release film according to any one of the preceding claims, wherein the first surface side of the carrier film has an average peak-to-valley height R.sub.z according to DIN EN ISO 4287 of at least 5.0 μm; preferably at least 7.0 μm, more preferably at least 9.0 μm, even more preferably at least 11 μm, most preferably at least 13 μm, and in particular at least 15 μm.

30. The release film according to any one of the preceding claims, wherein the first surface side of the carrier film preferably has an average peak-to-valley height R.sub.z according to DIN EN ISO 4287 of at most 100 μm; preferably at most 90 μm, more preferably at most 80 μm, even more preferably at most 70 μm, most preferably at most 60 μm, and in particular at most 50 μm.

31. The release film according to any one of the preceding claims, wherein the first surface side of the carrier film has an average peak-to-valley height R.sub.z according to DIN EN ISO 4287 in the range of 5.0 to 100 μm; preferably in the range of 10±5.0 μm, or 12.5±5.0 μm, or 15±5.0 μm, or 17.5±5.0 μm, or 20±5.0 μm, or 22.5±5.0 μm, or 25±5.0 μm, or 27.5±5.0 or 30±5.0 μm, or 32.5±5.0 μm, or 35±5.0 μm, or 37.5±5.0 μm, or 40±5.0 μm, or 42.5±5.0 μm, or 45±5.0 μm, or 47.5±5.0 μm, or 50±5.0 μm, or 52.5±5.0 μm, or 55±5.0 μm, or 57.5±5.0 μm, or 60±5.0 μm, or 62.5±5.0 μm, or 65±5.0 μm, or 67.5±5.0 μm, or 70±5.0 or 72.5±5.0 μm, or 75±5.0 μm, or 77.5±5.0 μm, or 80±5.0 μm, or 82.5±5.0 μm, or 85±5.0 μm, or 87.5±5.0 μm, or 90±5.0 μm, or 92.5±5.0 μm, or 95±5.0 μm.

32. The release film according to any one of the preceding claims, wherein the carrier film is single-layer.

33. The release film according to any one of claims 1 to 32, wherein the carrier film is multilayer.

34. The release film of claim 33, wherein the multilayer carrier film consists of a total of two, three, four, five, six, seven, eight, or nine layers; preferably two or three layers.

35. The release film of claim 33 or 34, wherein the multilayer carrier film has a symmetrical layer sequence.

36. The release film according to any one of claims 33 to 35, wherein the multilayer carrier film consists of a total of nine layers, wherein each three layers are identical.

37. The release film according to any one of the preceding claims, wherein the carrier film consists of a total of three layers: the first sealing layer (a) forming the first surface side; of layer (b); and the second sealing layer (c) forming the second surface side.

38. The release film according to any one of the preceding claims, wherein layer (b) forms the first surface side of the carrier film.

39. The release film according to any one of the preceding claims, wherein layer (b) forms the second surface side of the carrier film.

40. The release film according to any one of the preceding claims, wherein the first sealing layer (a) forms the first surface side of the carrier film.

41. The release film according to any one of the preceding claims, wherein the second sealing layer (c) forms the second surface side of the carrier film.

42. The release film according to any one of the preceding claims, wherein the carrier film is based on a polyolefin blend, or wherein the carrier film comprises at least one layer which is based on a polyolefin blend.

43. The release film according to claim 42, wherein the polyolefin blend comprises at least two polyolefins which are incompatible with one another.

44. The release film according to any one of the preceding claims, wherein the carrier film comprises an additive or the carrier film comprises at least one layer which comprises an additive, wherein the additive is selected from the group consisting of fillers, such as CaCO.sub.3, plasticizers; lubricants; emulsifiers; pigments; rheology additives; catalysts; flow control agents; optical brighteners; light stabilizers; antioxidants; clarifying agents such as substituted or unsubstituted bisbenzylidene sorbitols; flame retardants; antistatic agents; UV absorbers such as benzoxazinones; propellants; and thiosynergists such as thiodipropionic acid dilauryl esters or thiodipropionic acid distearyl esters.

45. The release film according to any one of the preceding claims, wherein the carrier film does not comprise a layer which is based on a nonwoven or comprises a nonwoven.

46. The release film according to any one of the preceding claims, wherein the carrier film does not comprise a layer which is based on paper or comprises paper.

47. The release film according to any one of the preceding claims, wherein the release coating has a basis weight of at least 0.1 g/m.sup.2; preferably at least 0.15 g/m.sup.2, more preferably at least 0.2 g/m.sup.2, even more preferably at least 0.25 g/m.sup.2, most preferably at least 0.3 g/m.sup.2, and in particular at least 0.35 g/m.sup.2.

48. The release film according to any one of the preceding claims, wherein the release coating has a basis weight of at most 0.6 g/m.sup.2; preferably at most 0.5 g/m.sup.2, more preferably at most 0.4 g/m.sup.2, even more preferably at most 0.3 g/m.sup.2, and most preferably at most 0.2 g/m.sup.2.

49. The release film according to any one of the preceding claims, wherein the release coating has a basis weight in the range of 0.1 g/m.sup.2 to 0.7 g/m.sup.2; preferably in the range of 0.3±0.2 g/m.sup.2, or 0.35±0.2 g/m.sup.2, or 0.4±0.2 g/m.sup.2, or 0.45±0.2 g/m.sup.2, or 0.5±0.2 g/m.sup.2; more preferably 0.4±0.2 g/m.sup.2; even more preferably 0.40±0.15 g/m.sup.2, most preferably 0.4±0.1 g/m.sup.2; and in particular 0.40±0.05 g/m.sup.2.

50. The release film according to any one of the preceding claims, wherein the release coating has a layer thickness of at least 0.10 μm; preferably at least 0.15 μm, more preferably at least 0.20 μm, even more preferably at least 0.25 μm, most preferably at least 0.30 μm, and in particular at least 0.35 μm.

51. The release film according to any one of the preceding claims, wherein the release coating preferably has a layer thickness of at most 4.0 μm; preferably at most 3.5 μm, more preferably at most 3.0 μm, even more preferably at most 2.5 μm, most preferably at most 2.0 μm, and in particular at most 1.0 μm.

52. The release film according to any one of the preceding claims, wherein the release coating has a layer thickness in the range of 0.10 to 4.0 μm; preferably in the range of 0.15±0.05 or 0.20±0.05 μm, or 0.25±0.05 μm, or 0.30±0.05 μm, or 0.35±0.05 μm, or 0.45±0.05 μm, or 0.50±0.05 μm, or 0.55±0.05 μm, or 0.60±0.05 μm, or 0.65±0.05 μm, or 0.70±0.05 μm, or 0.75±0.05 μm, or 0.80±0.05 μm, or 0.85±0.05 μm, or 0.90±0.05 μm, or 0.95±0.05 μm, or 1.5±0.5 μm, or 2.0±0.5 μm, or 2.5±0.5 μm, or 3.0±0.5 μm, or 3.5±0.5 μm.

53. The release film according to any one of the preceding claims, wherein the release coating is based on at least one cured polysiloxane selected from the group consisting of addition-crosslinked, preferably metal-catalyzed addition-crosslinked, condensation-crosslinked, free-radically crosslinked, and/or cationically crosslinked polysiloxanes; preferably radically crosslinked polysiloxanes; and/or polydialkylsiloxanes, preferably polydimethylsiloxanes; and polyalkylarylsiloxanes, preferably polymethylphenylsiloxanes; preferably chemically crosslinked acrylate-functionalized polysiloxanes; more preferably chemically crosslinked acrylate-functionalized polydialkylsiloxanes, preferably chemically crosslinked acrylate-functionalized polydimethylsiloxanes; or chemically crosslinked acrylate-functionalized polyalkylarylsiloxanes, preferably chemically crosslinked acrylate-functionalized polymethylphenylsiloxanes.

54. The release film according to claim 53, wherein the release coating comprises at least one further cured polysiloxane; preferably an acrylate-functionalized polydialkylsiloxane; preferably a chemically crosslinked long chain acrylate-functionalized polydialkylsiloxane;

55. The release film according to any one of the preceding claims, wherein the first sealing layer (a) has a layer thickness of at least 1.0 μm; preferably at least 2.0 μm, preferably at least 3.0 μm, preferably at least 4.0 μm, preferably at least 5.0 μm, more preferably at least 6.0 μm, even more preferably at least 7.0 μm, most preferably at least 8.0 μm, and in particular at least 9.0 μm.

56. The release film according to any one of the preceding claims, wherein the first sealing layer (a) has a layer thickness of at most 10 μm; preferably at most 9.0 μm, more preferably at most 8.0 μm, even more preferably at most 7.0 μm, most preferably at most 6.0 μm, and in particular at most 5.0 μm.

57. The release film according to any one of the preceding claims, wherein the first sealing layer (a) has a layer thickness in the range of 4.0 to 10 μm; preferably of 5.0 to 9.0 μm, and more preferably of 6.0 to 8.0 μm.

58. The release film according to any one of the preceding claims, wherein layer (b) has a layer thickness of at least 5.0 μm; preferably at least 6.0 μm, more preferably at least 8.0 μm, even more preferably at least 9.0 μm, most preferably at least 12 μm, and in particular at least 16 μm.

59. The release film according to any one of the preceding claims, wherein layer (b) has a layer thickness of at most 24.9 μm; preferably at most 22 μm, more preferably at most 20 μm, even more preferably at most 18 μm, most preferably at most 16 μm, and in particular at most 14 μm.

60. The release film according to any one of the preceding claims wherein layer (b) has a layer thickness in the range of 5.0 to 24.9 μm; preferably of 6.0 to 22 μm, more preferably of 8.0 to 20 μm, even more preferably from 9.0 to 18 μm, and most preferably of 12 to 16 μm.

61. The release film according to any one of the preceding claims, wherein the second sealing layer (c) has a layer thickness of at least 4.0 μm; preferably at least 5.0 μm, more preferably at least 6.0 μm, even more preferably at least 7.0 μm, most preferably at least 8.0 μm, and in particular at least 9.0 μm.

62. The release film according to any one of the preceding claims, wherein the second sealing layer (c) has a layer thickness of at most 10 μm; preferably at most 9.0 μm, more preferably at most 8.0 μm, even more preferably at most 7.0 μm, most preferably at most 6.0 μm, and in particular at most 5.0 μm.

63. The release film according to any one of the preceding claims, wherein the second sealing layer (c) has a layer thickness in the range of 4.0 to 10 μm; preferably of 5.0 to 9.0 μm, and more preferably of 6.0 to 8.0 μm.

64. The release film according to any one of the preceding claims, wherein the machine direction tensile strength of the release film is at least 6.5 N/cm, preferably determined according to DIN EN ISO 527-3.

65. The release film according to any one of the preceding claims, wherein the average release force of the release film Is at least 2.0 cN/cm; preferably at least 4.0 cN/cm, more preferably at least 6.0 cN/cm, even more preferably at least 8.0 cN/cm, most preferably at least 10 cN/cm, and in particular at least 12 cN/cm; Is at most 30 cN/cm; preferably at most 25 cN/cm, more preferably at most 20 cN/cm, even more preferably at most 15 cN/cm, most preferably at most 10 cN/cm, and in particular at most 8.0 cN/cm; and/or Is in the range of 2.0 to 30 cN/cm; preferably in the range of 6.0±4.0 cN/cm, or 10±8.0 cN/cm, or 10±4.0 cN/cm, or 14±12 cN/cm, or 14±8.0 cN/cm, or 14±4.0 cN/cm, or 18±12 cN/cm, or 18±8.0 cN/cm, or 18±4.0 cN/cm, or 22±8.0 cN/cm, or 22±4.0 cN/cm, or 26±4.0 cN/cm; preferably determined according to FINAT 10.

66. The release film according to any one of the preceding claims, wherein the difference between the maximum release force of the release film and the average release force of the release film is at most 20 cN/cm; preferably at most 15 cN/cm, more preferably at most 12.5 cN/cm, even more preferably at most 10 cN/cm, most preferably at most 7.5 cN/cm, and in particular at most 5.0 cN/cm; preferably determined according to FINAT 10.

67. The release film according to any one of the preceding claims, wherein the release force of the release film along the measuring section has a variance of at most 6.0 cN.sup.2/cm.sup.2; preferably at most 3.0 cN.sup.2/cm.sup.2, more preferably at most 1.5 cN.sup.2/cm.sup.2, even more preferably at most 0.8 cN.sup.2/cm.sup.2, most preferably at most 0.4 cN.sup.2/cm.sup.2, and in particular at most 0.2 cN.sup.2/cm.sup.2; preferably determined according to FINAT 10.

68. The release film according to any one of the preceding claims, wherein the release force of the release film over multiple measurements has a variance of at most 6.0 cN.sup.2/cm.sup.2; preferably at most 3.0 cN.sup.2/cm.sup.2, more preferably at most 1.5 cN.sup.2/cm.sup.2, even more preferably at most 0.8 cN.sup.2/cm.sup.2, most preferably at most 0.4 cN.sup.2/cm.sup.2, and in particular at most 0.2 cN.sup.2/cm.sup.2; preferably determined over at least two measurements, more preferably at least three measurements, even more preferably at least four measurements, most preferably at least five measurements, and in particular at least six measurements; preferably determined according to FINAT 10.

69. The release film according to any one of the preceding claims, wherein the release force of the release film over the entire surface coated using the release coating has a variance of at most 16 cN.sup.2/cm.sup.2; preferably at most 8.0 cN.sup.2/cm.sup.2, more preferably at most 4.0 cN.sup.2/cm.sup.2, even more preferably at most 2.0 cN.sup.2/cm.sup.2, most preferably at most 1.0 cN.sup.2/cm.sup.2, and in particular at most 0.5 cN.sup.2/cm.sup.2; preferably determined according to FINAT 10.

70. The release film according to any one of the preceding claims, wherein the release coating has a basis weight of at most 0.5 g/m.sup.2; preferably at most 0.45 g/m.sup.2; wherein the release coating is preferably based on at least one cured polysiloxane; preferably selected from the group consisting of polydialkylsiloxanes, preferably polydimethylsiloxanes; and polyalkylarylsiloxanes, preferably polymethylphenylsiloxanes; preferably chemically crosslinked acrylate-functionalized polysiloxanes; more preferably chemically crosslinked acrylate-functionalized polydialkylsiloxanes, preferably chemically crosslinked acrylate-functionalized polydimethylsiloxanes; or chemically crosslinked acrylate-functionalized polyalkylarylsiloxanes, preferably chemically crosslinked acrylate-functionalized polymethylphenylsiloxanes; wherein the release coating preferably comprises at least one other cured polysiloxane; preferably an acrylate-functionalized polydialkylsiloxane; preferably a chemically crosslinked long chain acrylate-functionalized polydialkylsiloxane; wherein the average release force of the release film is at most 30 cN/cm; preferably at most 25 cN/cm, more preferably at most 20 cN/cm, even more preferably at most 15 cN/cm, most preferably at most 12 cN/cm, and in particular at most 10 cN/cm; preferably determined according to FINAT 10; wherein the release force of the release film over multiple measurements has a variance of at most 6.0 cN.sup.2/cm.sup.2; preferably at most 3.0 cN.sup.2/cm.sup.2, more preferably at most 1.5 cN.sup.2/cm.sup.2, even more preferably at most 0.8 cN.sup.2/cm.sup.2, most preferably at most 0.4 cN.sup.2/cm.sup.2, and in particular at most 0.2 cN.sup.2/cm.sup.2; preferably determined over at least two measurements, more preferably at least three measurements, even more preferably at least four measurements, most preferably at least five measurements, and in particular at least six measurements; preferably determined according to FINAT 10; and optionally, wherein the first surface side of the carrier film has an embossed structure on at least part of its surface.

71. A method for producing a release film according to any one of the preceding claims by coating a carrier film using a release coating, wherein the method comprises the following steps: (a) providing a carrier film, wherein the carrier film has a first surface side and a second surface side; (b) providing a coating composition which comprises a solvent component and a silicone system curable by UV radiation; (c) coating at least a part of the first surface side of the carrier film provided in step (a) using the coating composition provided in step (b); (d) evaporating at least a part of the solvent component; and (e) irradiating at least a part of the first surface side of the carrier film coated in step (c) using UV radiation to cure the silicone system.

72. The method according to claim 71, wherein step (c) additionally comprises coating at least part of the second surface side of the carrier film provided in step (a) using the coating composition provided in step (b) or using another coating composition.

73. The method according to claim 71 or 72, wherein the silicone system curable by UV radiation is radically or cationically curable.

74. The method according to any one of claims 71 to 73, wherein the silicone system curable by UV radiation is based on at least one polysiloxane curable by UV radiation, which is selected from the group consisting of addition-crosslinking, preferably metal-catalyzed addition-crosslinking, condensation-crosslinking, free-radically crosslinking, and/or cationically crosslinking polysiloxanes.

75. The method according to any one of claims 71 to 74, wherein the release coating is based on at least one cured polysiloxane, which is selected from the group consisting of polydialkylsiloxanes, preferably polydimethylsiloxanes; and polyalkylarylsiloxanes, preferably polymethylphenylsiloxanes; preferably chemically crosslinked acrylate-functionalized polysiloxanes; more preferably chemically crosslinked acrylate-functionalized polydialkylsiloxanes, preferably chemically crosslinked acrylate-functionalized polydimethylsiloxanes; or chemically crosslinked acrylate-functionalized polyalkylarylsiloxanes, preferably chemically crosslinked acrylate-functionalized polymethylphenylsiloxanes;

76. The method according to any one of claims 71 to 75, wherein the content of the silicone system curable by UV radiation is at least 10 wt. %, based on the total weight of the coating composition; preferably at least 20 wt. %, more preferably at least 30 wt. %, even more preferably at least 40 wt. %, most preferably at least 50 wt. %, and in particular at least 60 wt. %.

77. The method according to any one of claims 71 to 76, wherein the content of the silicone system curable by UV radiation is at most 90 wt. %, based on the total weight of the coating composition; preferably at most 80 wt. %, more preferably at most 70 wt. %, more preferably at most 60 wt. %, most preferably at most 50 wt. %, and in particular at most 40 wt. %.

78. The method according to any one of claims 71 to 77, wherein the content of the silicone system curable by UV radiation is in the range of 10 to 90% wt. %, based on the total weight of the coating composition; preferably in the range of 20±10 wt. %, or 25±10 wt. %, or 30±10 30 wt. %, or 35±10 wt. %, or 40±10 wt. %, or 45±10 wt. %, or 50±10 wt. %, or 55±10 wt. %, or 60±10 wt. %, or 65±10 wt. %, or 70±10 wt. %, or 75±10 wt. %, or 80±10 wt. %.

79. The method according to any one of claims 71 to 78, wherein the solvent component comprises or consists of one or more C.sub.1-6alkyl acid C.sub.1-6alkyl esters.

80. The method according to any one of claims 71 to 79, wherein the solvent component comprises or consists of one or more C.sub.1-6alkyl alcohols.

81. The method according to any one of claims 71 to 80, wherein the solvent component comprises or consists of a solvent which has a dielectric constant of at least 2.40 F/m having; preferably at least 3.00 F/m, more preferably at least 3.50 F/m, even more preferably at least 4.00 F/m, most preferably at least 4.50 F/m, and in particular at least 5.00 F/m.

82. The method according to any one of claims 71 to 81, wherein the solvent component preferably comprises or consists of a solvent which has a dielectric constant of at most 16.00 F/m having; preferably at most 14.40 F/m, more preferably at most 12.40 F/m, even more preferably at most 10.40 F/m, most preferably at most 8.40 F/m, and in particular at most 6.40 F/m.

83. The method according to any one of claims 71 to 82, wherein the solvent component comprises or consists of a solvent which has a dielectric constant in the range of 2.40 F/m to 16.00 F/m; preferably in the range of 4.50±2.00 F/m, or 5.00±2.00 F/m, or 5.50±2.00 F/m, or 6.00±2.00 F/m, or 6.50±2.00 F/m, or 7.00±2.00 F/m, or 7.50±2.00 F/m, or 8.00±2.00 F/m, or 8.50±2.00 F/m, or 9.00±2.00 F/m, or 9.50±2.00 F/m, or 10.00±2.00 F/m, or 10.50±2.00 F/m, or 11.00±2.00 F/m, or 11.50±2.00 F/m, or 12.00±2.00 F/m, or 12.50±2.00 F/m, or 13.00±2.00 F/m, or 13.50±2.00 F/m, or 14.00±2.00 F/m.

84. The method according to any one of claims 71 to 83, wherein the solvent component comprises or consists of a solvent which has a boiling point of at least 70° C.; preferably at least 80° C., more preferably at least 90° C., even more preferably at least 100° C., most preferably at least 110° C., and in particular at least 120° C.

85. The method according to any one of claims 71 to 84, wherein the solvent component comprises or consists of a solvent which has a boiling point of at most 135° C.; preferably at most 125° C., more preferably at most 115° C., even more preferably at most 105° C., most preferably at most 95° C., and in particular at most 85° C.

86. The method according to any one of claims 71 to 85, wherein the solvent component comprises or consists of a solvent which has a boiling point in the range of 70° C. to 135° C.; preferably in the range of 80±10° C., or 85±10° C., or 90±10° C., or 95±10° C., or 100±10° C., or 105±10° C., or 110±10° C., or 115±10° C., or 120±10° C., or 125±10° C.

87. The method according to any one of claims 71 to 86, wherein the solvent component comprises or consists of a solvent which has a dipole moment of at least 1.75 D; preferably at least 1.77 D, more preferably at least 1.79 D, even more preferably at least 1.81 D, most preferably at least 1.83 D, and in particular at least 1.85 D.

88. The method according to any one of claims 71 to 87, wherein the solvent component comprises or consists of a solvent which has a dipole moment of at most 1.90 D; preferably at most 1.88 D, more preferably at most 1.86 D, even more preferably at most 1.84 D, most preferably at most 1.82 D, and in particular at most 1.80 D.

89. The method according to any one of claims 71 to 88, wherein the solvent component preferably comprises or consists of a solvent which has a dipole moment in the range of 1.75 D to 1.90 D; preferably in the range of 1.75 D to 1.90 D; preferably in the range of 1.77±0.02 D, or 1.78±0.02 D, or 1.79±0.02 D, or 1.80±0.02 D, or 1.81±0.05 D, or 1.82±0.02 D, or 1.83±0.05 D, or 1.84±0.02 D, or 1.85±0.02 D, or 1.86±0.02 D, or 1.87±0.02 D, or 1.88±0.02 D.

90. The method according to any one of claims 71 to 89, wherein the solvent component comprises or consists of a solvent having an evaporation number of at least 2.9; preferably at least 4.0, more preferably at least 5.0, even more preferably at least 6.0, most preferably at least 7.0, and in particular at least 8.0.

91. The method according to any one of claims 71 to 90, wherein the solvent component comprises or consists of a solvent which has an evaporation number of at most 12; preferably at most 12, more preferably at most 10, even more preferably at most 9.0, most preferably at most 8.0, and in particular at most 7.0.

92. The method according to any one of claims 71 to 91, wherein the solvent component comprises or consists of a solvent which has an evaporation number in the range of 2.9 to 11; preferably in the range of 4.0±1.0, or 4.5±1.0, or 5.0±1.0, or 5.5±1.0, or 6.0±1.0, or 6.5±1.0, or 7.0±1.0, or 7.5±1.0, or 8.0±1.0, or 8.5±1.0, or 9.0±1.0, or 9.5±1.0, or 10±1.0, or 10.5±1.0, or 11±1.0.

93. The method according to any one of claims 71 to 92, wherein the solvent component comprises or consists of a solvent selected from the group consisting of ethyl acetate, propyl acetate, butyl acetate, and mixtures thereof.

94. The method according to claim 93, wherein the solvent component comprises or consists of ethyl acetate.

95. The method according to claim 93, wherein the solvent component comprises or consists of propyl acetate; preferably n-propyl acetate, isopropyl acetate or a mixture thereof.

96. The method according to claim 93, wherein the solvent component preferably comprises or consists of butyl acetate; preferably n-butyl acetate, isobutyl acetate, sec-butyl acetate, tertbutyl acetate, or any mixtures thereof.

97. The method according to any one of claims 71 to 93, wherein the solvent component comprises or consists of a solvent selected from the group consisting of methanol, ethanol, propanol, butanol, ethoxypropanol, and mixtures thereof.

98. The method according to claim 97, wherein the solvent component comprises or consists of propanol; preferably n-propanol, isopropanol, or mixtures thereof.

99. The method according to any one of claims 71 to 98, wherein the solvent component comprises or consists of at least two solvents.

100. The method according to claim 99, wherein the at least two solvents of the solvent component are in a ratio in the range of 5:1 to 1:1; preferably 4:1 to 1:1, preferably 3:1 to 1:1, even more preferably 2:1 to 1:1, and in particular in a ratio of 1:1.

101. The method according to any one of claims 71 to 100, wherein the solvent component comprises or consists of one or more C.sub.1-6alkyl acid C.sub.1-6alkyl esters and one or more C.sub.1-6alkyl alcohols.

102. The method according to any one of claims 71 to 101, wherein the solvent component comprises or consists of at least two solvents which are selected from the group consisting of ethyl acetate, propyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, ethoxypropanol, and mixtures thereof.

103. The method according to claim 102, wherein the solvent component comprises or consists of ethyl acetate and propanol; preferably n-propanol, isopropanol or a mixture thereof particularly preferably n-propanol.

104. The method according to any one of claims 71 to 103, wherein the content of the solvent component is at least 10 wt. %, based on the total weight of the coating composition; preferably at least 20 wt. %, more preferably at least 30 wt. %, even more preferably at least 40 wt. %, most preferably at least 50 wt. %, and in particular at least 60 wt. %.

105. The method according to any one of claims 71 to 104, wherein the content of the solvent component is at most 90 wt. %, based on the total weight of the coating composition; preferably at most 80 wt. %, more preferably at most 70 wt. %, more preferably at most 60 wt. %, most preferably at most 50 wt. %, and in particular at most 40 wt. %.

106. The method according to any one of claims 71 to 105, wherein the content of the solvent component is in the range of 10 to 90% wt. %, based on the total weight of the coating composition; preferably in the range of 20±10 wt. %, or 25±10 wt. %, or 30±10 wt. %, or 35±10 wt. %, or 40±10 wt. %, or 45±10 wt. %, or 50±10 wt. %, or 55±10 wt. %, or 60±10 wt. %, or 65±10 wt. %, or 70±10 wt. %, or 75±10 wt. %, or 80±10 wt. %.

107. The method according to any one of claims 71 to 106, wherein the coating composition has a viscosity of at least 1.0 mm.sup.2/s; preferably at least 1.5 mm.sup.2/s, more preferably at least 2.0 mm.sup.2/s, even more preferably at least 2.5 mm.sup.2/s, most preferably at least 3.0 mm.sup.2/s, and in particular at least 3.5 mm.sup.2/s; and/or at most 100 mm.sup.2/s; preferably at most 90 mm.sup.2/s, more preferably at most 80 mm.sup.2/s, even more preferably at most 70 mm.sup.2/s, most preferably 60 mm.sup.2/s, and in particular at most 50 mm.sup.2/s.

108. The method according to any one of claims 71 to 107, wherein the coating composition has a viscosity of at most 20 mm.sup.2/s; preferably at most 19 mm.sup.2/s, more preferably at most 18 mm.sup.2/s, even more preferably at most 17 mm.sup.2/s, most preferably 16 mm.sup.2/s, and in particular at most 15 mm.sup.2/s; and/or in the range of 1.0 to 100 mm 2/S; preferably in the range of 15±10 mm 2/s, or 20±10 mm 2/s, or 25±10 mm 2/s, or 30±10 mm 2/s, or 35±10 mm 2/s, or 40±10 mm 2/s, or 45±10 mm 2/s, or 50±10 mm 2/s, or 55±10 mm 2/s, or 60±10 mm 2/s, or 65±10 mm 2/s, or 70±10 mm 2/s, or 75±10 mm 2/s, or 80±10 mm 2/s, or 85±10 mm.sup.2/s, or 90±10 mm.sup.2/s.

109. The method according to any one of claims 71 to 108, wherein the coating composition has a flow time out of a measuring cup of at least 5.0 s; preferably at least 10 s, more preferably at least 12 s, even more preferably at least 14 s, most preferably at least 16 s, and in particular at least 18 s; and/or of at most 30 s; preferably at most 29 s, more preferably at most 28 s, even more preferably at most 27 s, most preferably at most 26 s, and in particular at most 25 s; each preferably determined using a measuring cup having a flow opening of 3 mm; each preferably determined using a measuring cup according to DIN EN ISO 2431.

110. The method according to any one of claims 71 to 109, wherein the coating composition has a flow time out of a measuring cup of at most 25 s; preferably at most 24 s, more preferably at most 23 s, even more preferably at most 22 s, most preferably at most 21 s, and in particular at most 20 s; and/or in the range of 5.0 to 30 s; preferably in the range of 8.0 to 28 s; more preferably 11 to 26 s, even more preferably 14 to 24 s, most preferably 16 to 23 s, and in particular 18 to 22 s; each preferably determined using a measuring cup having a flow opening of 3 mm; each preferably determined using a measuring cup according to DIN EN ISO 2431.

111. The method according to any one of claims 71 to 110, wherein the viscosity of the coating composition is determined using a measuring cup according to DIN EN ISO 2431.

112. The method according to claim 111, wherein a measuring cup having a flow opening of 6 mm is used; preferably 5 mm, more preferably 4 mm, and particularly preferably 3 mm.

113. The method according to any one of claims 71 to 112, wherein the coating composition contains a catalyst which catalyzes the curing of the polysiloxane curable by UV radiation.

114. The method according to claim 113, wherein the catalyst is selected from the group consisting of α-hydroxy, α-alkoxy or α-amino aryl ketones, acylphosphine oxides, aliphatic azo compounds, or onium compounds.

115. The method according to any one of claims 71 to 114, wherein step (c) comprises cooling the coating composition in the system.

116. The method according to any one of claims 71 to 115, wherein the coating in step (c) takes place at a temperature of at least 5.0° C.; preferably at least 7.0° C., more preferably at least 9.0° C., even more preferably at least 11° C., most preferably at least 13° C., and in particular at least 15° C.

117. The method according to any one of claims 71 to 116, wherein the coating in step (c) preferably takes place at a temperature of at most 20° C.; preferably at most 18° C., more preferably at most 16° C., even more preferably at most 14° C., most preferably at most 12° C., and in particular at most 10° C.

118. The method according to any one of claims 71 to 117, wherein the coating in step (c) preferably takes place at a temperature in the range of 5.0° C. to 20° C.; preferably in the range of 6.0±2.0° C., or 7.0±2.0° C., or 8.0±2.0° C., or 9.0±2.0° C., or 10±2.0° C., or 11±2.0° C., or 12±2.0° C., or 13±2.0° C., or 14±2.0° C., or 15±2.0° C., or 16±2.0° C., or 17±2.0° C., or 18±2.0° C.

119. The method according to any one of claims 71 to 118, wherein step (c) comprises applying the coating composition to at least part of the first surface side of the carrier film using a printing method, preferably a flexographic printing method.

120. The method according to any one of claims 71 to 119, wherein step (c) comprises applying the coating composition to at least part of the first surface side of the carrier film using an anilox roller.

121. The method according to any one of claims 71 to 120, wherein step (c) comprises coating at least 50% of the first surface side; preferably at least 60%, more preferably at least 70%, more preferably at least 80%, most preferably at least 90%, and in particular completely (100%).

122. The method according to any one of claims 71 to 121, wherein the evaporation of the solvent component in step (d) takes place at a temperature of at least 30° C.; preferably at least 40° C., more preferably at least 50° C., even more preferably at least 60° C., most preferably at least 70° C., and in particular at least 80° C.

123. The method according to any one of claims 71 to 122, wherein the evaporation of the solvent component in step (d) takes place at a temperature of at most 180° C.; preferably at most 170° C., more preferably at most 160° C., even more preferably at most 150° C., most preferably at most 140° C., and in particular at most 130° C.

124. The method according to any one of claims 71 to 123, wherein the evaporation of the solvent component in step (d) takes place at a temperature in a range of 30° C. to 180° C.; preferably in the range of 50±20° C., or 60±20° C., or 70±20° C., or 80±20° C., or 90±20° C., or 100±20° C., or 110±20° C., or 120±20° C., or 130±20° C., or 140±20° C., or 150±20° C., or 160±20° C.

125. The method according to any one of claims 71 to 124, wherein the evaporation of the solvent component in step (d) takes place at a pressure of at least 100 mbar; preferably at least 150 mbar, more preferably at least 200 mbar, even more preferably at least 250 mbar, most preferably at least 300 mbar, and in particular at least 350 mbar.

126. The method according to any one of claims 71 to 125, wherein the evaporation of the solvent component in step (d) takes place at a pressure of at most 900 mbar; preferably at most 850 mbar, more preferably at most 800 mbar, even more preferably at most 750 mbar, most preferably at most 700 mbar, and in particular at most 650 mbar.

127. The method according to any one of claims 71 to 126, wherein the evaporation of the solvent component in step (d) takes place at a pressure in the range of 100 mbar to 900 mbar; preferably in the range of 150±50 mbar, or 200±50 mbar, or 250±50 mbar, or 300±50 mbar, or 350±50 mbar, or 400±50 mbar, or 450±50 mbar, or 500±50 mbar, or 550±50 mbar, or 600±50 mbar, or 650±50 mbar, or 700±50 mbar, or 750±50 mbar, or 800±50 mbar, or 850±50 mbar.

128. The method according to any one of claims 71 to 127, wherein step (d) comprises evaporating the solvent component to odor neutrality.

129. The method according to claim 128, wherein the solvent component is evaporated in step (d) down to a residual content of the solvent component of at most 100 ppmw; preferably at most 80 ppmw, more preferably at most 60 ppmw, even more preferably at most 40 ppmw, most preferably at most 20 ppmw, in particular completely (0 ppmw).

130. The method according to any one of claims 71 to 129, wherein at least part of the coated first surface side of the carrier film is irradiated in step (e) at a wavelength of at least 170 nm; preferably at least 190 nm, more preferably at least 210 nm, even more preferably at least 230 nm, most preferably at least 250 nm, and in particular at least 270 nm.

131. The method according to any one of claims 71 to 130, wherein at least part of the coated first surface side of the carrier film is irradiated in step (e) at a wavelength of at most 400 nm; preferably at most 380 nm, more preferably at most 360 nm, even more preferably at most 340 nm, most preferably at most 320 nm, and in particular at most 300 nm.

132. The method according to any one of claims 71 to 131, wherein at least part of the coated first surface side of the carrier film is irradiated in step (e) at a wavelength in the range of 170 nm to 400 nm; preferably in the range of 190±20 nm, or 200±20 nm, or 210±20 nm, or 220±20 nm, or 230±20 nm, or 240±20 nm, or 250±20 nm, or 260±20 nm, or 270±20 nm, or 280±20 nm, or 290±20 nm, or 300±20 nm, or 310±20 nm, or 320±20 nm, or 330±20 nm, or 340±20 nm, or 350±20 nm, or 360±20 nm, or 370±20 nm, or 380±20 nm.

133. The method according to any one of claims 71 to 132, wherein at least part of the coated first surface side of the carrier film is irradiated in step (e) using an energy of at least 3.0 eV; preferably at least 4.0 eV, more preferably at least 5.0 eV, even more preferably at least 6.0 eV, most preferably at least 7.0 eV, and in particular at least 8.0 eV.

134. The method according to any one of claims 71 to 133, wherein at least part of the coated first surface side of the carrier film is irradiated in step (e) using an energy of at most 12 eV; preferably at most 11 eV, more preferably at most 10 eV, even more preferably at most 9.0 eV, most preferably at most 8.0 eV, and in particular at most 7.0 eV.

135. The method according to any one of claims 71 to 134, wherein at least part of the coated first surface side of the carrier film is preferably irradiated in step (e) using an energy in the range of 3.0 eV to 12 eV; preferably in the range of 5.0±2.0 eV, or 6.0±2.0 eV, or 7.0±2.0 eV, or 8.0±2.0 eV, or 9.0±2.0 eV, or 10±2.0 eV.

136. The method according to any one of claims 71 to 135, wherein at least part of the coated first surface side of the carrier film is irradiated in step (e) under a protective gas atmosphere.

137. The method according to claim 136, wherein the protective atmosphere essentially comprises nitrogen.

138. The method according to any one of claims 71 to 137, wherein step (e) comprises irradiating at least 50% of the coated first surface side; preferably at least 60%, more preferably at least 70%, more preferably at least 80%, most preferably at least 90%, and in particular completely (100%).

139. The method according to any one of claims 71 to 138, wherein step (a) additionally comprises surface activation of at least the first surface side of the carrier film provided in (a).

140. The method according to claim 139, wherein the surface activation is carried out by a pretreatment with plasma or corona.

141. A use of a release film according to any one of claims 1 to 70 as a detachable release and/or protective film for adhesive hygiene items.

Description

EXAMPLE 1

[0372] Multiple release films have been produced by coating release films using a release coating. The viscosity of the coating composition and the solvent contained in the coating composition were varied and the influence on the release force (TK) of the release films was studied. Furthermore, the scoop volume of the anilox roller used to apply the coating composition was varied.

[0373] The components of the coating composition are summarized in the following table:

TABLE-US-00002 wt. % solvent 65-75 acrylate modified silicone copolymer 20-30 long chain acrylate silicone polymer 1.0-2.0 photoinitiator (catalyst) 0.5-1.5

[0374] After storage for 20 h at 70° C. (or at 40° C. for examples 1-3) the release force (TK) of the release films was measured according to FINAT 10 at a peeling speed of 300 mm/min in comparison to a test adhesive tape TESA® 7475 (or 7476 for examples 1-3) from Beiersdorf. Three tests were carried out at the infeed and at the end of each release film.

[0375] The results are shown in FIGS. 1 to 7; FIG. 1 shows the release force (TK) for example 1-1, FIG. 2 for example 1-2, FIG. 3 for example 1-3, FIG. 4 for example 1-4, FIG. 5 for example 1-5, FIG. 6 for example 1-6, and FIG. 7 for example 1-7. The results of the tests at the infeed (FIGS. 1A, 2A, 3A, 4A, 5A, 6A, and 7A) and at the end (FIGS. 1B, 2B, 3B, 4B, 5B, 6B, and 7B) of each release film are shown.

[0376] The results are summarized in the following table:

TABLE-US-00003 1-1 1-2 1-3 1-4 1-5 1-6 1-7 ethyl acetate [%] 100 100 100 100 80 50 100 n-propanol [%] — — — — — 50 — ethoxypropanol [%] — — — — 20 — — anilox roller 5 5 5 5 5 5 4 [cm.sup.3/m.sup.2] infeed/end in end in end in end in end in end in end in end viscosity 30 28 27 19 20.5 20.5 — 21.2 19.4 19.3 (3 mm cup) [s] basis weight [g/m.sup.2] 0.73 0.55 0.73 0.69 0.59 0.57 0.27 0.255 0.315 0.345 0.285 0.3 0.41 0.43 TK1 [cN/cm] 13.5 18.9 19.3 23.1 28.3 32.7 8.3 8.2 9.0 7.2 7.7 7.2 6.7 6.6 TK1max [cN/cm] 27.7 29.0 58.2 45.4 51.2 41.9 11.9 11.6 19.8 10.9 11.0 11.0 10.1 9.9 TK2 [cN/cm] 22.6 31.0 23.5 23.7 29.5 32.6 9.1 8.8 9.5 7.6 7.6 7.4 7.2 7.2 TK2max [cN/cm] 35.2 67.4 53.4 44.7 38.8 41.6 14.1 12.4 15.0 11.7 10.4 10.9 10.7 10.1 TK3 [cN/cm] 22.5 27.2 28.2 23.0 28.5 33.0 8.9 8.6 8.7 7.5 7.3 7.2 7.9 7.0 TK3max [cN/cm] 43.5 47.8 44.2 40.7 37.5 42.9 24.0 13.0 14.3 16.5 10.1 12.2 14.0 11.8 Ø TK [cN/cm] 19.5 25.7 23.7 23.3 28.8 32.8 8.8 8.5 9.1 7.4 7.5 7.3 7.3 6.9 σ.sup.2 TK [cN.sup.2/cm.sup.2] 18.20 25.53 13.22 0.10 0.28 0.03 0.12 0.06 0.11 0.03 0.03 0.01 0.24 0.06 Ø TK total [cN/cm] 22.62 23.47 30.77 8.65 8.25 7.40 7.10 σ.sup.2 TK total 31.37 6.70 4.15 0.10 0.74 0.04 0.18 [cN.sup.2/cm.sup.2]

[0377] As the data in the table above shows, the viscosity of the coating composition in particular has a significant influence on the release force (TK). At a lower viscosity (shorter flow time in the 3 mm cup) and a comparable basis weight, a significantly lower release force is achieved. In addition, a more even distribution of the release force along the measuring section is achieved at a lower viscosity, which is expressed, among other things, by the smaller measured values for TK1max, TK2max, and TK3max, but also in particular by the variance (σ.sup.2). The release forces determined in the individual measurements for TK1, TK2, and TK3 deviate significantly more from one another at higher viscosities than at lower viscosities (e.g., 1-1:13.5, 22.6, and 22.5 (σ.sup.2 18.20) vs. 1-6:7.7, 7.6, and 7.3 (σ.sup.2 0.03)).