BARRIER PAPER

Abstract

The present invention relates to a barrier paper comprising at least a base paper, at least one coating colour layer S1 applied directly or indirectly to the base paper, at least one barrier layer B1 applied directly or indirectly to the coating colour layer S1, a coating B2 applied directly or indirectly to the barrier layer B1.

Claims

1. A barrier paper comprising at least a base paper, at least one coating colour layer S1 applied directly or indirectly to the base paper, at least one barrier layer B1 applied directly or indirectly to the coating colour layer S1, a coating B2 applied directly or indirectly to the barrier layer B1.

2. The barrier paper according to claim 1, characterized in that the coating colour layer S1 has at least one of the following properties: water vapour barrier, oxygen barrier, mineral oil barrier, aroma barrier, grease barrier, buckling resistance of at least one property, grease resistance, sealability, Bekk smoothness of at least 200 Bekk seconds.

3. The barrier paper according to claim 1, characterized in that the coating colour layer S1 comprises or consists of at least one water-soluble polymer and/or at least one water-dispersible polymer.

4. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and/or the at least one water-dispersible polymer is selected from the group consisting of: polyvinyl alcohol, in particular partially saponified or fully saponified; polyvinyl alcohol copolymer, in particular copolymerized with ethylene, polyvinyl amine, acrylic acid derivatives, partially saponified or fully saponified; modified fully or partially saponified polyvinyl alcohols or copolymers, in particular modifications with acyl, alkyl, acrylamide, silanol, diacetone, acetoacetyl, itaconic acid; polymer with an onset temperature of less than 210 C. as determined by DSC, wherein the onset temperature is determined by DSC according to DIN EN ISO 11357-1:2010-03 as the intersection of the extrapolated baseline and the inflection tangent at the beginning of the melting or crystallization peak; acrylic-based polymers; polyester-based polymers; nitrocellulose-based polymers; polyvinyl acetate-based polymers.

5. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and/or the at least one water-dispersible polymer comprise an at least partially saponified polyvinyl alcohol and/or an at least partially saponified polyvinyl alcohol copolymer, each with an onset temperature of less than 210 C. as determined by DSC.

6. The barrier paper according to at claim 3, characterized in that the at least one water-soluble polymer and/or the at least one water-dispersible polymer comprise a partially saponified polyvinyl alcohol with a degree of saponification of 30% to 95%, an average molecular weight of more than 0 and less than 100,000 g/mol, and with an onset temperature of less than 200 C. as determined by DSC.

7. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and/or the at least one water-dispersible polymer comprise a partially saponified polyvinyl alcohol with a degree of saponification of greater than 95% to 100%, an average molecular weight of more than 70,000 g/mol, and with an onset temperature of less than 200 C. as determined by DSC.

8. The barrier paper according to claim 3, characterized in that the at least one water-soluble polymer and/or the at least one water-dispersible polymer comprise a partially saponified polyvinyl alcohol copolymer, preferably a partially saponified polyethylene vinyl alcohol, with a degree of saponification of 95% to 100%, an average molecular weight of more than 60000 g/mol, and with an onset temperature of less than 210 C. as determined by DSC.

9. The barrier paper according to claim 3, characterized in that the partially saponified polyvinyl alcohol and/or the partially saponified polyvinyl alcohol copolymer have a viscosity of less than 30 mPas at a dry content of 4%, particularly preferably less than 20 mPas and most particularly preferably less than 15 mPas.

10. A barrier paper. characterized in that the at least one water-soluble polymer and/or the at least one water-dispersible polymer comprises a mixture of the polymers defined in 3.

11. The barrier paper according to claim 1, characterized in that the coating colour layer S1 has a surface tension in the range of 25 to 80 mN/m, in particular 25 to 75 mN/m.

12. The barrier paper according, claim 1, characterized in that the barrier layer B1 comprises or consists of metals, in particular Al, Cu, Sn, Zn, Ag, Au, Ti, In, Si, metal alloys, metal oxides, in particular Al.sub.2O.sub.3, SiO.sub.2, mixed oxides or a combination thereof.

13. The barrier paper according to claim 1, characterized in that the barrier layer B1 is applied by vacuum deposition.

14. The barrier paper according to claim 1, characterized in that the barrier layer B1 has at least one of the following features: a) optical density1.5 and 6.0, b) layer thickness5 nm, preferably 10 nm, particularly preferably 15 nm, especially 5 nm to 150 nm

15. The barrier paper according to claim 1, characterized in that the coating B2 comprises or consists of at least one polymer, in particular a polymer selected from the group comprising a) polyethylene acrylic acid copolymers, B) polyolefins, c) polyvinyl alcohols, d) cellulose nitrates, e) bio-based polymers f) non-biobased polymers g) styrene-butadiene latices, h) acrylate latices.

16. The barrier paper according to claim 1, characterized in that the coating B2 has at least one of the following properties: a) protection of barrier layer B1 against external influences, in particular mechanical or chemical influences, b) sealable, in particular hot, ultrasonic, and cold sealable, c) grease resistance, d) water resistance, e) moisture resistance, f) printability, g) additional barrier property.

17. The barrier paper according to claim 1, characterized in that the barrier paper has at least one of the following features: a) WVTR5 g/m2/d at 23 C. and 50% relative humidity, b) WVTR inside fold5 g/m2/d at 23 C. and 50% relative humidity, c) WVTR outside fold5 g/m2/d at 23 C. and 50% relative humidity, d) WVTR15 g/m2/d at 38 C. and 90% relative humidity, e) WVTR inside fold15 g/m2/d at 38 C. and 90% relative humidity, f) WVTR outside fold15 g/m2/d at 38 C. and 90% relative humidity, g) OTR10 g/m.sup.2/d at 23 C. and 50% relative humidity, h) OTR inside fold10 g/m2/d at 23 C. and 50% relative humidity, i) OTR outside fold10 g/m2/d at 23 C. and 50% relative humidity, j) buckling resistance of at least one barrier property, especially in the area of the inside fold and/or the outside fold, k) residual moisture content of at least 2.5% (w/w), in particular at least 3.0% (w/w) based on the total weight of the barrier paper.

18. The barrier paper according to claim 1, characterized in that the coating colour layer S1, the barrier coating B1 and the coating B2 are removable in the waste paper cycle.

19. The barrier paper according to claim 18, characterized in that the barrier paper after reprocessing according to INGEDE method 11 achieves the following scores according to the Assessment of Printed Product Recyclability, Deinkability Score: a) Luminosity Y maximum of 35 points, b) Colour coefficient a* in the CIELAB system maximum of 20 points, c) Dirt specks A in the two different size classes A50 maximum of 15 points and A250 maximum of 10 points, d) Degree of dye elimination (ink elimination) IE maximum of 10 points, and e) Filtrate darkening Y maximum of 10 points, wherein the sum of all points is in the range from 0 to 100, preferably in the range from 51 to 70, more preferably in the range from 71 to 100, and/or preferably no individual point value is negative.

20. The barrier paper according to claim 1, characterized in that a precoat comprising at least one inorganic pigment and a polymeric binder is present between the base paper and the coating colour layer S1, wherein the inorganic pigment is preferably platelet-shaped and preferably comprises a talc, a precipitated calcium carbonate, a silicate, preferably a phyllosilicate or kaolin, and/or the polymeric binder comprises a polymeric binder based on a polyacrylate or styrene-butadiene.

21. The barrier paper according to claim 1, characterized in that the basis weight of the coating colour layer S1 and of the coating B2 is in the range from 4 to 20 g/m.sup.2, preferably from 4 to 15 g/m.sup.2, based on the dried end product (air dry).

22. The barrier paper according to claim 1, characterized in that the barrier paper is free of halogenated organic compounds.

23. The barrier paper according to claim 1, characterized in that the base paper has a basis weight of 20 to 120 g/m.sup.2, preferably 40 to 100 g/m.sup.2.

24. The barrier paper according to claim 1, characterized in that the base paper has a long fibre content of 10 to 80% and a short fibre content of 20 to 90% (w/w), wherein a long fibre is a fibre with a fibre length of 2.6 to 4.4 mm, and a short fibre is a fibre with a fibre length of 0.7 to 2.2 mm.

25. The barrier paper according to claim 1, characterized in that the base paper comprises up to 90% recycled fibres.

26. The barrier paper according to claim 1, characterized in that the values for the loss factors tan Delta measured as a function of the temperature by means of dynamic mechanical thermal analysis (DMTA) of the barrier paper pass through a maximum at the temperature Tg and a first inflection point at the temperature Tw with increasing temperature.

27. The barrier paper according to claim 26, characterized in that the temperature Tg is lower than the temperature Tw.

28. The barrier paper according to claim 26, characterized in that the amount of the difference between tan delta at the temperature Tg and tan delta at the temperature Tw is >0.013, preferably >0.014 and particularly preferably >0.015.

29. A method for producing a barrier paper according to claim 1, characterized in that an aqueous suspension comprising the starting materials of the coating colour layer is applied to the base paper, wherein the aqueous coating suspension has a solids content of 5 to 50 wt %, preferably 10 to 30 wt %, and is applied by a curtain coating process, preferably by a double curtain coating process with an operating speed of the coating plant of at least 200 m/min.

30. (canceled)

31. A package comprising a barrier paper according to claim 1, wherein the package is preferably a cold-sealed package, a heat-sealed package, an ultrasonically sealed package, in particular a tubular bag package.

Description

FIGURES

[0322] FIG. 1 shows two basic structures a) and b) of barrier papers according to the invention with the following reference signs: [0323] 1: Base paper [0324] g: smoother surface of the base paper [0325] r: rougher surface of the base paper [0326] 2: Coating colour layer S1 [0327] 3: Barrier layer B1 [0328] 4: Coating B2 [0329] 5: Precoat, optional for better coating colour hold-out to prevent the coating colour layer S1 from seeping into the base paper [0330] 6: Starch precoat, optional for better printability [0331] 7: Barrier paper according to the invention [0332] A: Sealing surface A of the barrier paper [0333] B: Sealing surface B of the barrier paper [0334] A/A sealing [0335] A/B sealing [0336] 8: Further coating colour layer S1, same or different composition/layer thickness as 2

[0337] Not shown: Printing on the barrier paper using standard printing processes, in particular by means of flexographic, gravure or digital printing processes.

[0338] FIG. 2 shows two SEM surface images of comparative example V3 (inside fold) in different resolutions. The top coating (B1) as top view. As can be seen, this is broken in the surface due to the buckling strain.

[0339] FIG. 3 shows two SEM surface images of example B1 (inside fold) different resolutions. The top coating (coating B2) as top view. As can be seen, that although the coating is strained due to the buckling stress, it is not broken.

[0340] FIG. 4 shows two SEM surface images of comparative example V5 (inside fold). The top coating (B2) as top view. The coating colour layer S1 is missing here. As can be seen, this is broken in the surface due to the buckling strain.

[0341] FIG. 5 shows two images after the palm kernel fat test (inside fold on the left, outside fold on the right) of comparative example V1. The top coating (coating colour layer S1) as top view. In this case, the layer thickness was halved. It can be seen that this halving does not lead to any problems in the flat grease barrier (to the right and left of the fold), but does lead to problems in the buckling resistance (grease seepage in the fold and in the edge area of the fold).

[0342] FIG. 6 shows two images after the palm kernel fat test (inside fold on the left, outside fold on the right) of comparative example V2. The top coating (coating colour layer S1) as top view. In this case, a preferred layer thickness was selected. It can be seen that there are no problems with either the flat grease barrier (to the right and left of the fold) or the buckling resistance (no grease penetration in the fold and in the edge area of the fold).

[0343] FIG. 7 shows various packaging shapes with A:A sealing according to the invention.

[0344] FIG. 8 shows an envelope packaging according to the invention with A:B sealing on the front side.

[0345] FIG. 9 shows a schematic representation of a graph of a typical DMTA measurement for a barrier paper according to the invention. The measured values for the loss factor tan Delta are plotted as a function of the temperature. As the temperature increases, there is initially a maximum at the temperature Tg and then a first inflection point at the temperature Tw.

[0346] FIG. 10 shows a DMTA measurement for the examples 9 and 10 according to the invention in comparison with the comparative example V2 according to Table 2.

[0347] The present invention is explained in more detail below in several examples. The examples serve only to illustrate the invention, but do not limit it.

EXAMPLES

[0348] The following coatings were applied to a base paper with a basis weight of 60 g/m.sup.2 or 70 g/m.sup.2 and with 40% long fibre and 60% short fibre content, using 100% virgin fibre pulp.

Precoat:

[0349] In all examples, the precoat contains 75.9% pigment (phyllosilicate), 22.8% latex (styrene-acrylate latex) and 1.3% rheology modifiers (0.2% acrylate-based thickener, 1.1% zirconium-based crosslinker).

[0350] The precoat was applied to the base paper using a doctor blade.

Coating Colour Layer S1:

[0351] In examples 1 to 5, polyvinyl alcohols were used as polymers. In examples 6 to 8, partially saponified polyethylene vinyl alcohols were used as polymers.

[0352] The coating colour layer S1 of examples 1 to 5 comprises a pure polymer coating. Example 1 comprises a polymer coating with 99.8% polyvinyl alcohol as polymer (example 1; degree of saponification: 87%; M.sub.w: 50900) and 0.2% rheology modifiers (Na docusate).

[0353] The coating colour layer S1 of examples 9 and 10 and of comparative examples 1, 2, 3, and 5 corresponds to the coating colour layer S1 of example 1. The use of the coating colour layer S1 from example 1 led to comparable results.

Barrier Layer B1:

[0354] In Examples 9 and 10 and Comparative Examples 1, 2, 3 and 5, an approximately 40 nm to 80 nm thick barrier layer B1 was applied directly to the coating colour layer S1 or to the precoat by means of vacuum deposition of aluminum.

Coating B2:

[0355] Embodiment by means of gravure printing and embodiment by means of curtain coating.

[0356] The following properties were examined: [0357] Basis or application weights: [0358] Application weight of the coatings in g/m.sup.2. This is as determined by differential weighing of coated and uncoated papers. [0359] Viscosity: The viscosity was determined with a Brookfield viscometer [0360] at 23 C. and a speed of 100 rpm, with a dry content of 4%. [0361] WVTR: Water vapour transmission rate, determined according to ASTM D 1653. [0362] For folded samples, a 180-fold is produced with a roller that exerts a load of 330 g/cm on the resulting fold, and wherein the coating can be on the inside (inside fold) or the outside (outside fold). [0363] OTR: Oxygen transmission rate, determined according to DIN 15105-2 [0364] For folded samples, a 180-fold is produced with a roller that exerts a load of 330 g/cm on the resulting fold, and wherein the coating can be on the inside (inside fold) or the outside (outside fold). [0365] HVTR: Hexane vapour transmission rate. Here, n-hexane is filled into a beaker (solvent-resistant), tightly sealed with the test specimen and the weight loss is followed over time. For folded samples, a 180-fold is produced with a roller that exerts a load of 330 g/cm on the resulting fold, and wherein the coating can be on the inside (inside fold) or outside (outside fold). [0366] Palm kernel fat test: Analogous to DIN 53116. For folded samples a 180-fold is produced with a roller that exerts a load of 330 g/cm on the resulting fold and where the coating can be on the inside (inside fold) or the outside (outside fold). [0367] Display paper: Evaluation of the display paper mentioned in DIN 53116. For this, fat penetration points with a diameter (d) of <1 mm (first value in table) and >1 mm are counted (second value in table) [0368] Test paper: Evaluation of the reverse side of the Test paper mentioned in DIN 53116. This is not part of the standard, but was carried out for better differentiation. [0369] Sealed-seam strength: The samples are sealed at 3.3 bars for 0.3 s in the temperature range from 100 C. to 220 C. transverse to the paper running direction and the sealed-seam strength is determined in accordance with DIN 55529 (2012). The optimum sealing temperature and, for comparison, the sealing force at 150 C. (optimum sealing temperature of example 1) are given. [0370] Coefficient of friction: The static and kinetic coefficients of friction were determined in accordance with ISO 8295. [0371] Coefficient of friction back against back: [0372] Two test specimens are aligned with their function-coated sides to each other, and the coefficient of friction is determined (inside/inside) [0373] Coefficient of friction back against barrier side: [0374] The function-coated side (barrier side) of the barrier paper is measured against the metal surface of the device (inside/barrier side). [0375] DSC melting temperature/onset: [0376] The DSC curves were measured with a Mettler DSC 20 S in [0377] cold-welded aluminum crucibles and perforated lids. The heating rates were 10 K/min in the range between 30 C. and 280 C. The melting temperatures were determined via the peak minima of the melting process. Necessary? [0378] Surface tension (surface energy): [0379] Contact angle measuring device OCA 20 (DataPhysics) with software SCA 20 [0380] Measuring principle: OWRK method (Owens, Wendt, Rabel, Kaelble) [0381] Measuring liquids used and origin of the material constants entered: [0382] Water and diiodomethane (according to Buscher) and 1,5-pentanediol (according to Gebhardt) [0383] Friction sensitivity 1) Measure the barrier property of the upper barrier paper [0384] Oser test 2) Place barrier papers on top of each other in the Oser test device (barriers pointing downwards), weigh down with 500 g and switch on the device for 60 seconds. Then lift the weight off again [0385] 3) Measure the barrier property of the upper barrier paper.

[0386] The barrier papers obtained were examined. The results are shown in the following tables.

[0387] Table 1 shows the results for intermediate products that only have the coating colour layer S1, but have no barrier layer B1 and no coating B2 yet (examples Ex. 1 to Ex. 8).

[0388] Table 2 shows the results for barrier papers according to the invention, which in particular have a coating colour layer S1, a barrier layer B1 and a coating B2 (examples Ex. 9 and Ex. 10), as well as the comparative examples V1 to V5.

[0389] The partially saponified polyvinyl alcohols used have very low hexane and oxygen transmission rates. This is probably due to their comparatively high hydrophilicity.

[0390] The polyvinyl alcohols with a higher degree of saponification are characterized in the coating colour by a higher viscosity with the same dry content. This only makes sense from a chemical point of view, as the higher polarity means that each molecule interacts more strongly with the surrounding solvent (water).

[0391] This must be considered as rather disadvantageous, since a large amount of water has to be dried in the coating process at low dry contents. This not only costs energy, but can also be difficult to realize in terms of application technology, depending on the desired application weight. In addition, the diffusion of water molecules and thus the drying process itself is slowed down. Furthermore, the accumulation of gaseous water in the coating is more likely to occur, leading to the formation of macroscopic coating defects.

[0392] The water vapour permeability of the polyethylene vinyl alcohols tested is lower than that of the polyvinyl alcohols, which is presumably due to the ethylene content and the associated lower hydrophilicity.

[0393] In general, fully saponified polyvinyl alcohols (PVOH) should be more brittle than partially saponified PVOH due to the larger number of hydrogen bonds they can form.

[0394] In particular, in order to maintain the essential or all barrier properties of the barrier papers even in the crease fold or crease area after buckling, the barrier papers according to all embodiments of the invention have the following characteristics: [0395] a) For all barrier papers according to these examples, the values for the loss factors tan Delta measured by means of dynamic mechanical thermal analysis (DMTA) of the barrier paper as a function of the temperature pass through a maximum at the temperature Tg and a first inflection point at the temperature Tw with increasing temperature. [0396] b) For all barrier papers according to these examples, the temperature Tg is also lower than the temperature Tw. [0397] c) The amount of the difference between tan Delta at temperature Tg and tan Delta at temperature Tw is >0.013 for all barrier papers according to these examples.

[0398] Without being bound by this theory, the inventors considered the following:

[0399] The dynamic mechanical thermal analysis (DMTA) shows that the barrier papers according to the invention can maintain a barrier after buckling if the barrier papers have a significant viscoelastic component. A so-called rubber-elastic-regime state can be interpreted by quantifying the change in the tan delta value (tan at the glass transition temperature (Tg) to the first inflection point (Tw) of the tan delta curve with increasing temperature. A barrier material that retains its barrier properties after buckling, which surprisingly can also include a metal-coated layer, has a tan delta change of >0.013.

[0400] The dynamic mechanical thermal analysis (DMTA) also provides the glass transition temperature (Tg)the temperature at which the macromolecule polymer chains transition from a solid, frozen state to a mobile state, but before the macromolecule polymer chains slide past each other, which is the melting point (Tm). It is advantageous if an elastic state is present in the barrier paper, in order to maintain a barrier after creasing or folding; therefore, a Tg below the operating and usage temperature is ideal. In the DSC, the Tg is as determined by the temperature at which the tan delta reaches a maximum. One of the examples has a glass transition temperature Tg=8.4 C. corresponding to the tan delta maximum of 0.099 and a tan delta change of 0.0185.

TABLE-US-00001 TABLE 1 Ex. 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Raw material Sealcoat Sealcoat Poval Poval Poval Poval Exceval Exceval Poval HS 25 HS 25 28-99 4-85 8-88 5-88 HR 3010 RS 2117 4-98 Basis weight g/m.sup.2 10.3 10.0 10.4 10.1 9.7 10.1 9.1 10.3 9.7 coating colour layer S1 Viscosity* mPas 9 9 26 7 10 9 17 25 8 OTR 23.0 C./0% r.h. cm.sup.3/m.sup.2/d 1.86 1.12 1.33 16.64 1.53 1.12 0.04 0.04 3.05 HVTR g/m.sup.2/d <10 <10 <10 <10 <10 <10 <10 <10 <10 Folded (inside) g/m.sup.2/d <10 <10 <10 <10 <10 <10 <10 <10 <10 Folded (outside) g/m.sup.2/d <10 <10 <10 <10 <10 <10 <10 <10 <10 Palm kernel fat test Display paper (AP) d </> 1 mm 0/0 0/0 0/0 0/0 0/0 0/0 0/0 1/0 0/0 Test paper (PP) d </> 1 mm 0/0 0/0 0/0 0/0 0/0 0/0 0/0 1/0 0/0 AP - inside fold d </> 1 mm 0/0 0/0 0/0 0/1 0/0 0/0 0/0 0/0 0/1 PP - inside fold d </> 1 mm 0/0 0/0 0/0 0.5/0 0/0 0/0 0/0 0/0 0/1 AP - outside fold d </> 1 mm 0/0 0/0 0/0 0/0 2/0 0/0 0/0 0/0 0/0 PP - outside fold d </> 1 mm 0/0 0/0 0/0 0/0 0/2 3/0 1/10 1/0 2/12 Sealed-seam strength N/15 mm 6.9 6.7 0.7 4.5 5.0 7.2 0.0 0.0 0.6 (cold tack) at 150 C. Optimum sealing C. 150 150 200 160 130-160 150 190 190 210 temperature WVTR Ambient, 23 C., 50% r.H. g/m.sup.2/d 8.3 7.6 12.7 26.0 9.5 16.0 1.0 1.9 8.0 DSC melting temperature C. 195 195 224 189 190 191 218 217 222 DSC - onset C. 178 178 187 158 165 169 203 199 221 Degree of saponification % 87 87 99 85 88 88 99 98-99 98 Aver. Molecular mass g/mol 50,900 50900 91,200 38,900 56,700 64,700 87,900 35,000 Surface tension or energy mN/m 58.35 66.73 55.93 54.06 54.98 43.73 44.27 60.26

TABLE-US-00002 TABLE 2 Ex. 9 Ex. 10 V1 V2 V3 V4 V5 Basis paper g/m.sup.2 60 60 60 60 60 70 70 basis weight Basis weight g/m.sup.2 4 4 4 4 4 10 10 precoat Basis weight g/m.sup.2 10 10 5 10 10 coating colour layer S1 Polymer coating colour polyvinyl polyvinyl polyvinyl polyvinyl polyvinyl layer S1 alcohol alcohol alcohol alcohol alcohol (Sealcoat (Sealcoat (Sealcoat (Sealcoat (Sealcoat HS25) HS25) HS25) HS25) HS25) Layer thickness nm 40-80 (Al) 40-80 (Al) 40-80 (Al) 40-80 (Al) Barrier layer B1 Basis weight g/m.sup.2 6 5 1 Coating B2 Polymer coating B2 polyethylene acrylic polyolefin nitrocellulose/ acid (Wkoseal 630, by (Hypod 2000/ cellulose nitrate pressure chamber Dow Chemical) gravure printing) Residual moisture % (w/w) >2.5 >2.5 4.5 4.5 Barrier paper OTR 23 C./50% r.h. cm.sup.3/m.sup.2/d 3.5 3.5 >100 4 4 . OTR 23 C./50% r.h. cm.sup.3/m.sup.2/d 7 4 . 650 720 Inside fold OTR 23 C./50% r.h. cm.sup.3/m.sup.2/d 15 13 Outside fold Scratch resistance of cm.sup.3/m.sup.2/d the oxygen barrier (OTR) WVTR 23 C./50% r.h. g/m.sup.2/d 0.7 0.3 12.8 0.5 7.4 WVTR 23 C./50% r.h. g/m.sup.2/d 0.6 0.5 12.3 0.3 58.9 Inside fold WVTR 23 C./50% r.h. g/m.sup.2/d 0.5 1.1 11.6 2 76.3 Outside fold WVTR 38 C./90% r.h. g/m.sup.2/d 16 19 >100 70 WVTR 38 C./90% r.h. g/m.sup.2/d 17 18 >100 79 Inside fold WVTR 38 C./90% r.h. g/m.sup.2/d 17 21 >100 66 Outside fold WVTR loaded with g/m.sup.2/d 11 18 >100 140 grease Scratch resistance of g/m.sup.2/d the water vapour barrier (WVTR) HVTR g/m.sup.2/d 0 0.5 10 0.5 1 55 HVTR inside fold g/m.sup.2/d 0.5 1 11 0.5 8 952 HVTR outside fold g/m.sup.2/d 0.9 2 13 35 60 835 Palm kernel fat test Display paper 0/0 0/0 1/1 0/0 0/0 30/11 (AP) penetrations <1 mm/ >1 mm Palm kernel fat test Test paper 0/0 0/0 40/10 0/0 0/0 15/27 (PP) penetrations <1 mm/ >1 mm Palm kernel fat test AP - inside 0/0 0/0 15/7 0/0 0/1 >100/>100 fold penetrations <1 mm/ >1 mm Palm kernel fat test PP - inside 0/0 0/0 5/12 0/0 1/1 >100/>100 fold penetrations <1 mm/ >1 mm Palm kernel fat test AP - outside 0/0 0/0 7/15 10/1 1/1 >100/>100 fold penetrations <1 mm/ >1 mm Palm kernel fat test PP - outside 3/5 3/2 10/13 10/16 >100/>100 >100/>100 fold penetrations <1 mm/ >1 mm Optimum sealing C. 190 160 160 160 no no no temperature sealing sealing sealing Sealed-seam strength N/15 mm 9.6 2.4 5.1 6.9 no no no (cold tack) sealing sealing sealing Coefficient of friction Back against 0.251 0.85 0.33 0.304 0.409 (CoF) back, dynamic Coefficient of friction Back against 0.189 0.597 0.292 0.325 0.38 (CoF) back, static Coefficient of friction Back against 0.318 0.517 0.245 0.249 0.423 (CoF) barrier layer B1 dynamic Coefficient of friction Back against 0.27 0.558 0.185 0.214 0.39 (CoF) barrier layer B1 static Total surface tension mN/m 28.7 40.3 50.8 27.6 39.48 Surface tension mN/m 25.8 13.3 22.5 26.6 28.11 dispersed Surface tension polar mN/m 2.9 27.0 28.2 1.0 11.37 DMTA See FIG. 10 See FIG. 10 See FIG. 10