EP4074891B1 - Neues substrat - Google Patents
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- EP4074891B1 EP4074891B1 EP21168232.3A EP21168232A EP4074891B1 EP 4074891 B1 EP4074891 B1 EP 4074891B1 EP 21168232 A EP21168232 A EP 21168232A EP 4074891 B1 EP4074891 B1 EP 4074891B1
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- paper
- density
- dry weight
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- density paper
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- 239000000758 substrate Substances 0.000 title claims description 62
- 239000000123 paper Substances 0.000 claims description 182
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 77
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 74
- 238000000034 method Methods 0.000 claims description 53
- 239000011122 softwood Substances 0.000 claims description 37
- 239000000203 mixture Substances 0.000 claims description 36
- 239000001301 oxygen Substances 0.000 claims description 35
- 229910052760 oxygen Inorganic materials 0.000 claims description 35
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 34
- 229920000642 polymer Polymers 0.000 claims description 32
- 239000011121 hardwood Substances 0.000 claims description 29
- 230000004888 barrier function Effects 0.000 claims description 22
- 239000002655 kraft paper Substances 0.000 claims description 19
- 239000004715 ethylene vinyl alcohol Substances 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 18
- 238000004806 packaging method and process Methods 0.000 claims description 18
- 238000007670 refining Methods 0.000 claims description 18
- 229920001046 Nanocellulose Polymers 0.000 claims description 17
- 229920002678 cellulose Polymers 0.000 claims description 17
- 239000001913 cellulose Substances 0.000 claims description 17
- 239000011248 coating agent Substances 0.000 claims description 14
- 238000000576 coating method Methods 0.000 claims description 14
- 229920002472 Starch Polymers 0.000 claims description 10
- 235000013305 food Nutrition 0.000 claims description 10
- 239000008107 starch Substances 0.000 claims description 10
- 235000019698 starch Nutrition 0.000 claims description 10
- 239000002245 particle Substances 0.000 claims description 9
- 125000002057 carboxymethyl group Chemical group [H]OC(=O)C([H])([H])[*] 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 108700005457 microfibrillar Proteins 0.000 claims description 4
- 229920000881 Modified starch Polymers 0.000 claims description 3
- 239000004952 Polyamide Substances 0.000 claims description 3
- 235000019426 modified starch Nutrition 0.000 claims description 3
- 229920002647 polyamide Polymers 0.000 claims description 3
- 239000005033 polyvinylidene chloride Substances 0.000 claims description 3
- LEQAOMBKQFMDFZ-UHFFFAOYSA-N glyoxal Chemical compound O=CC=O LEQAOMBKQFMDFZ-UHFFFAOYSA-N 0.000 description 24
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 23
- 229920001684 low density polyethylene Polymers 0.000 description 23
- 239000004702 low-density polyethylene Substances 0.000 description 23
- 239000000835 fiber Substances 0.000 description 16
- YSGSDAIMSCVPHG-UHFFFAOYSA-N valyl-methionine Chemical compound CSCCC(C(O)=O)NC(=O)C(N)C(C)C YSGSDAIMSCVPHG-UHFFFAOYSA-N 0.000 description 14
- 229940015043 glyoxal Drugs 0.000 description 12
- 239000010410 layer Substances 0.000 description 12
- 239000005022 packaging material Substances 0.000 description 12
- 241001454667 Perga Species 0.000 description 11
- 239000011087 paperboard Substances 0.000 description 11
- 229920001131 Pulp (paper) Polymers 0.000 description 10
- 230000005540 biological transmission Effects 0.000 description 10
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 description 9
- RZXDTJIXPSCHCI-UHFFFAOYSA-N hexa-1,5-diene-2,5-diol Chemical compound OC(=C)CCC(O)=C RZXDTJIXPSCHCI-UHFFFAOYSA-N 0.000 description 9
- 238000001878 scanning electron micrograph Methods 0.000 description 9
- 239000011888 foil Substances 0.000 description 8
- 238000004064 recycling Methods 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 7
- 239000004971 Cross linker Substances 0.000 description 7
- 229910052782 aluminium Inorganic materials 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- 238000005452 bending Methods 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 6
- 238000005470 impregnation Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 6
- 239000011256 inorganic filler Substances 0.000 description 5
- 229910003475 inorganic filler Inorganic materials 0.000 description 5
- 239000000523 sample Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- 239000002648 laminated material Substances 0.000 description 4
- 229920001526 metallocene linear low density polyethylene Polymers 0.000 description 4
- IMROMDMJAWUWLK-UHFFFAOYSA-N Ethenol Chemical compound OC=C IMROMDMJAWUWLK-UHFFFAOYSA-N 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 3
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 238000011049 filling Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000004537 pulping Methods 0.000 description 3
- 239000003570 air Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000003869 coulometry Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 235000021149 fatty food Nutrition 0.000 description 2
- 239000011084 greaseproof paper Substances 0.000 description 2
- 235000021056 liquid food Nutrition 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000007639 printing Methods 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 238000004347 surface barrier Methods 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 102100031260 Acyl-coenzyme A thioesterase THEM4 Human genes 0.000 description 1
- 235000018185 Betula X alpestris Nutrition 0.000 description 1
- 235000018212 Betula X uliginosa Nutrition 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 101000638510 Homo sapiens Acyl-coenzyme A thioesterase THEM4 Proteins 0.000 description 1
- 241000218657 Picea Species 0.000 description 1
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 1
- 241000018646 Pinus brutia Species 0.000 description 1
- 235000011613 Pinus brutia Nutrition 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 235000014121 butter Nutrition 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000003490 calendering Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 235000013351 cheese Nutrition 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000010981 drying operation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000010954 inorganic particle Substances 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 229920000092 linear low density polyethylene Polymers 0.000 description 1
- 239000004707 linear low-density polyethylene Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 238000012858 packaging process Methods 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
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- 239000000126 substance Substances 0.000 description 1
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- 238000005303 weighing Methods 0.000 description 1
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Images
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
- D21H17/24—Polysaccharides
- D21H17/25—Cellulose
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
- B65D65/38—Packaging materials of special type or form
- B65D65/40—Applications of laminates for particular packaging purposes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
- B65D65/38—Packaging materials of special type or form
- B65D65/42—Applications of coated or impregnated materials
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
- D21H17/24—Polysaccharides
- D21H17/25—Cellulose
- D21H17/26—Ethers thereof
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
- D21H17/24—Polysaccharides
- D21H17/28—Starch
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/33—Synthetic macromolecular compounds
- D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D21H17/36—Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/10—Packing paper
Definitions
- the present disclosure relates to a paper substrate to be used in a multi-layered material for packing of oxygen-sensitive goods, such as foods.
- Paperboard-based packaging laminates for liquid food packaging typically include an aluminum foil to render the packaging container gas-tight, in particular oxygen tight.
- WO 2011/003565 discloses a packaging laminate in which the aluminum foil is replaced with a paper or cellulose-based material (a "substrate") that is precoated and then covered by a metal vapor deposited layer. It is stated that the basis weight (grammage) of the substrate preferably is from 20 to 100 g/m 2 .
- WO 2017/089508 discloses further details about such a substrate, namely that it is a compact-surface barrier paper having a density of 800 kg/m 3 or higher, a surface roughness value below 450 ml/min (Bendtsen, ISO 8791-2), a thickness of 60 ⁇ m or lower and a grammage of 60 g/m 2 or lower.
- a specific example of the compact-surface barrier paper is "Super Perga WS" (Nordic Paper) having a grammage of 32 g/m 2 and a surface roughness value of about 200 ml/min.
- An objective of the present disclosure is to provide a new cellulose-based substrate that improves the barrier properties of non-aluminum foil packaging. Another objective is to provide a new cellulose-based substrate that facilitates recycling of a packaging material comprising the substrate. A final, general objective is to reduce the environmental impact of packaging materials.
- a high-density paper having a grammage measured according to ISO 536:2012 of 30-75 g/m 2 and a density measured according to ISO 534:2011 above 1000 kg/m 3 .
- a high density is preferably obtained by supercalendering.
- the high-density paper of the present disclosure is preferably supercalendered.
- the density is at least 1050 kg/m 3 , such as at least 1070 kg/m 3 .
- a typical upper limit for the density may be 1300 kg/m3.
- the high-density paper is impregnated on each side with 0.3-4.0 g/m 2 , such as 0.5-4.0 g/m 2 , such as 0.5-3.0 g/m 2 , of a polymer.
- "Impregnated" means that the polymer to a substantial degree has penetrated the fibre web. However, it does not necessarily mean that the fibre web, across its thickness direction, has been completely saturated with the polymer. Consequently, the high-density paper may comprise unfilled pores, especially in the middle. Here it is also referred to the discussion about figure 2 below. Hence, it may be determined by a SEM image of a cross section of the high-density paper that the polymer has penetrated the fiber web rather than formed a coating layer on the surface.
- the polymer is selected from the group consisting of polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), carboxymethylated cellulose (CMC), nanocrystalline cellulose (NCC) and carboxy methyl starch (CMS). PVOH, EVOH and CMC are preferred examples of the polymer. In one embodiment, the polymer is PVOH or EVOH.
- the polymer is preferably water-soluble or water-dispersible.
- the most preferred polymer in the group is PVOH.
- the degree of hydrolysis of the PVOH maybe 96%-100%, such as 97%-100%, such as 97%-99%.
- a PVOH having a high degree of hydrolysis is less sensitive to water and is preferred, both in production and in use.
- the weight average molecular weight (M w ) of the PVOH is preferably below 100,000 g/mol, such as 10,000-90,000 g/mol, such as 30,000-80,000 g/mol. Such a relatively low M w is preferred during impregnation since it has a relatively low viscosity at a relatively high concentration.
- a PVOH of low M w has a greater tendency to penetrate into the fiber web rather than staying of the surface of paper.
- the viscosity of the PVOH when measured according to DIN 53015 is preferably below 20 mPa*s, such as 5-16 mPa*s, such as 6-13 mPa*s.
- the degree of polymerization (DP) of the PVOH is preferably below 3000, such as 1000-2000.
- the DP can be determined from the viscosity-average degree of polymerization derived from the viscosity in water. In such case, viscosity is measured in a 4% aqueous solution at 20 °C and determined by Brookfield synchronized-motor rotary type viscometer.
- PVOH polyvinyl styrene resin
- Kuraray which has a viscosity of 10 mPa*s, a degree of hydrolysis of 98%, a DP of about 1400 and a M w of about 61,000 g/mol.
- Another example is Poval 6/98 from Kuraray, which has a viscosity of 6 mPa*s and a degree of hydrolysis of 98%.
- the PVOH or EVOH may comprise a cross-linker, such as glyoxal.
- the glyoxal to PVOH dry weight ratio may be between 3:100 and 12:100, preferably between 4:100 and 9:100, more preferably between 5:100 and 8:100.
- EVOH has high moisture resistance and excellent oxygen barrier properties.
- An example of an EVOH is Exceval ® AQ-4104 from Kuraray, which provides for low viscosity.
- the polymer may also be NCC, which is a form of nano-cellulose, but not the same as microfibrillar cellulose ("MFC”) or nanofibrillar cellulose (“NFC”).
- MFC microfibrillar cellulose
- NFC nanofibrillar cellulose
- MFC should denote nano scale cellulose particle fibers or fibrils or fibril aggregates with at least one dimension of less than 100 nm.
- MFC may thus contain longer particles, so-called “fibrils” having a width of 10-100 nm, and a length of at least 1 ⁇ m, such as up to 10 ⁇ m, such as longer than 10 ⁇ m.
- Both MFC and NFC have an aspect ratio of 50 or above, while NCC may defined to have an aspect ratio below 50, e.g. in accordance with the draft TAPPI norm WI3021.
- NCC is used for shorter particles and "rod-like" particles, having a width of 3-50 nm, and a length from 100 up towards 1000 nm, such as from 100 to 900 nm, such as from 100 to 500 nm, such as from 100 to 200 nm.
- the preferred dimensions of NCC for the purpose of impregnating and filling pores in a formed paper, meaning that the majority of the NCC particles in the composition should have this dimension, may be a length of 100-500 nm, such as 100-200 nm and a width of 3-50 nm.
- the high-density paper is formed from at least 50% by dry weight chemical pulp, such as at least 75% by dry weight chemical pulp, such as at least 85% by dry weight chemical pulp, such as at least 95% by dry weight chemical pulp.
- the chemical pulp is preferably kraft pulp, but it may also be sulfite pulp (i.e. pulp obtained by the sulfite pulping process).
- 20-65 % by dry weight, such as 30-60 % by dry weight, of the pulp used to form the high-density paper is hardwood pulp.
- 35-80 % by dry weight, such as 40-70 % by dry weight, of the pulp used to form the high-density paper is softwood pulp.
- a benefit of including hardwood pulp is that it collapses relatively easy during refining, while it still allows for efficient dewatering in the wire section of the paper machine.
- a benefit of including softwood pulp is improved runnability in the paper machine and beneficial strength/toughness properties in the resulting paper. The latter properties may be improved by subjecting the softwood pulp to high consistency (HC) refining.
- HC high consistency
- the high-density paper has a top ply and a bottom ply.
- the properties of the top ply may be tailored for receiving another barrier layer, while the bottom ply properties are tailored for strength/toughness.
- the top ply may be tailored for printing, while the bottom ply is coated with (a) further layer(s).
- the top ply is formed from at least 50% by dry weight hardwood pulp, such as at least 65% by dry weight hardwood pulp, such as at least 75% by dry weight hardwood pulp.
- Hardwood pulp may provide an improved surface for printing or another barrier layer.
- the bottom ply is formed from at least 50% by dry weight softwood pulp, such as at least 65% by dry weight softwood pulp, such as at least 75% by dry weight softwood pulp.
- softwood is associated with better runnability in the paper machine and provides beneficial strength/toughness properties in the resulting paper product.
- the bottom ply side is impregnated with a higher amount of polymer than the top ply.
- the grammage measured according to ISO 536:2012 is 35-65 g/m 2 .
- a relatively low grammage may be beneficial since it may require less polymer in a packaging application, e.g. in order to make tight and durable seals when transforming the laminated material into filled and sealed, cuboid-shaped packages.
- the use of less polymer facilitates recycling streams of high fiber content.
- package integrity improves when the paper substrate grammage is lower.
- the strength and toughness of the paper may be insufficient if the grammage is too low.
- At least one side of the high-density paper has a Bendtsen roughness measured according to SS-ISO 8791-2:2013 of 7-80 ml/min, such as 8-70 ml/min, such as 10-60 ml/min, such as 30-60 ml/min.
- both sides of the high-density paper has a Bendtsen roughness measured according to SS-ISO 8791-2:2013 of 7-80 ml/min, such as 8-70 ml/min, such as 10-60 ml/min.
- the beneficial barrier and recycling properties are obtained without sacrificing strength, such as tensile strength and tear strength.
- the tensile index measured in the MD according to ISO 1924-3:2005 is preferably above 100 Nm/g, such as 110-150 Nm/g.
- the tensile index measured in the CD according to ISO 1924-3:2005 is preferably above 50 Nm/g, such as 55-90 Nm/g, such as 65-90 Nm/g.
- the tear index measured in the machine direction (MD) according to ISO 1924-3:2005 is at least 4.1 mNm 2 /g, such as at least 4.4 mNm 2 /g and/or the tear index measured in the cross direction (CD) according to ISO 1924-3:2005 of at least 4.9 mNm 2 /g, such as at least 5.3 mNm 2 /g.
- Typical upper limits in MD and CD may be 6.5 mNm 2 /g and 7.5 mNm 2 /g, respectively.
- the high density is obtained without any substantial addition of inorganic filler to the furnish.
- Silica or bentonite used as retention agent typically in an amount of less than 1 kg per tonne dry pulp, is not considered to be inorganic filler.
- the ash content measured according to ISO 2144:2015 of the high-density paper is preferably less than 5% by dry weight, such as less than 3% by dry weight, such as less than 1% by dry weight.
- the high-density paper of the present disclosure may be obtained without extensive low consistency (LC) refining, which improves the speed of the papermaking process (and reduces its energy consumption) and facilitates recycling. Such a comparatively limited refining can be reflected by the drainability measured after repulping.
- the high-density paper exhibits a Schopper-Riegler (°SR) number measured according to ISO 5267-1:1999 of 33-50, such as 35-45, after repulping according to ISO 5263-1:2004.
- Another drainability value is Canadian Standard Freeness (CSF).
- the high-density paper exhibits a CSF measured according to ISO 5267-2:2001 of at least 200 ml, such as 200-450 ml, such as 200-350 ml, after repulping according to the Valmet repulping method carried out in a Valmet repulper of the type HD400.
- the Valmet repulping method is described below in the Examples section.
- the high-density paper has a fines content measured with a L&W Fibretester+ (ABB, Lorentzen & Wettre, Sweden) of less than 40%, such as less than 34%, such as less than 32%, after repulping according to ISO 5263-1:2004.
- L&W Fibretester+ ABB, Lorentzen & Wettre, Sweden
- Fines are defined as fibrous particles shorter than 0.2 mm.
- the L&W Fibretester+ operates according to ISO 16065-2:2014.
- a typical lower limit for the fines content is 15% or 20%.
- a high-density paper having a grammage measured according to ISO 536:2012 of 30-75 g/m 2 and a density measured according to ISO 534:2011 above 1000 kg/m 3 and wherein the high-density paper is impregnated on at least one side with a composition comprising polyvinyl alcohol (PVOH) and glyoxal.
- PVOH polyvinyl alcohol
- the glyoxal to PVOH dry weight ratio in the composition of the configuration may be between 3:100 and 12:100, preferably between 4:100 and 9:100, more preferably between 5:100 and 8:100.
- the high-density paper of the first aspect is not PECVD- or PVD-coated.
- the high-density paper of this embodiment may be intended for PECVD or PVD coating.
- PECVD means plasma-enhanced chemical vapor deposition.
- PVD means plasma vapor deposition.
- a method of forming a high-density paper having a grammage measured according to ISO 536:2012 of 30-75 g/m 2 and a density measured according to ISO 534:2011 of above 1000 kg/m 3 said method comprising the steps of:
- the impregnating step comprises adding an aqueous composition comprising the polymer to each side of the paper substrate.
- the viscosity measured at 60°C of the aqueous composition may be 55-90 mPa*s. Such a relatively low viscosity facilitates penetration of the polymer into the fiber web.
- the concentration of the polymer in the aqueous composition is preferably 7.0%-13.0% (w/v), such as 8.0%-12.0% (w/v).
- the 60°C viscosity measurement is preferably carried out using a Brookfield rotational viscometer equipped with spindle no.3 at 100 rpm.
- the polymer is PVOH or EVOH and the aqueous composition further comprises a crosslinker, such as a glyoxal crosslinker.
- a crosslinker such as a glyoxal crosslinker.
- the dry weight ratio of PVOH or EVOH to glyoxal crosslinker in the aqueous composition may be from 100:3 to 100:8, such as from 100:4 to 100:7.
- the aqueous composition may further comprise inorganic particles, preferably in a low amount.
- the impregnated substrate entering the supercalendering step preferably has a relatively high moisture content, such as 11.0%-20.0%. More preferably, the moisture content is 12.0%-19.0%, such as 13.5%-18.0%.
- the impregnated substrate is dried after the impregnating step to a moisture content below 11%, such as below 10%, such as below 9%. Then, it is re-moisturized prior to the supercalendering step, e.g. to a moisture content in the range of 11.0%-20.0%, 12.0%-19.5% or 13.5%-18.0%.
- the impregnating step is preferably carried out by means of a size press or a film press.
- a film press is the most preferred equipment.
- the film press may be an OptiSizer Film (Valmet) or a SpeedSizer (Voith).
- the number of nips of the supercalendering step may be 7-19, preferably 11-17.
- the surface temperature of the thermo rolls of the supercalendering step may be 120-160 °C.
- the total nip impulse of the supercalendering step may be at least 600 kPa*s.
- the head box consistency or the head box consistencies in case of a multiply paper is/are in the range of 0.06%-0.60%, such as 0.10%-0.40%, such as 0.10%-0.30%.
- Such relatively low consistencies facilitate the production of a paper of low porosity, which means a high density.
- the paper substrate of the second aspect is formed from at least 50% by dry weight chemical pulp, such as at least 75% by dry weight chemical pulp, such as at least 85% by dry weight chemical pulp, such as at least 95% by dry weight chemical pulp.
- the chemical pulp is preferably kraft pulp, but may also be sulfite pulp.
- the paper substrate of the second aspect is formed from 20-65 % by dry weight hardwood pulp, such as 30-60 % by dry weight hardwood pulp and/or 35-80 % by dry weight softwood pulp, such as 40-70 % by dry weight softwood pulp.
- HC refining When softwood pulp is used, it may have been subjected to high consistency (HC) refining, i.e. refining at a consistency of 20%-40%, such as 25%-38%.
- the specific energy of the HC refining step may be at least 100 kWh/tonne, such as at least 150 kWh/tonne, such as 150-300 kWh/tonne.
- the "tonne" of the unit means tonne of dry fiber.
- the paper substrate of the second aspect has a first ply and a second ply.
- a first wire may be used to form a first web that becomes the top ply and a second wire may be used to form a second web that becomes the second ply, which first and second web are couched together.
- the first web may be formed from a first furnish comprising at least 50% by dry weight hardwood pulp, such as at least 65% by dry weight hardwood pulp, such as at least 75% by dry weight hardwood pulp.
- the head box consistency of the first furnish maybe 0.12%-0.60%, such as 0.18%-0.35%.
- the Schopper-Riegler (°SR) number measured according to ISO 5267-1:1999 of the first furnish in the head box may be 33-45.
- Such a SR number may facilitate a sufficiently high density without causing dewatering and/or recycling problems and may be obtained by adjusting the degree of low consistency (LC) refining.
- the second web may be formed from a second furnish comprising at least 50% by dry weight softwood pulp, such as at least 65% by dry weight softwood pulp, such as at least 75% by dry weight softwood pulp.
- This softwood pulp preferably has been subjected to high consistency (HC) refining (suitable specific energies are discussed above).
- HC high consistency
- the head box consistency of the second furnish maybe 0.06%-0.40%, such as 0.10%-0.25%.
- the head box consistency of the second furnish is lower than the head box consistency of the first furnish.
- the Schopper-Riegler (°SR) number measured according to ISO 5267-1:1999 of the second furnish in the head box may be 25-35.
- Such a SR number may facilitate sufficiently high density without causing dewatering and/or recycling problems and may be obtained by adjusting the degree of low consistency (LC) refining.
- the furnishes comprises less than less than 2% by weight inorganic filler, such as less than 1% by dry weight inorganic filler, such as substantially no inorganic filler.
- the second ply side is impregnated with a higher amount of polymer than the first ply.
- the high-density paper of the first aspect is an excellent substrate for a coating, in particular an oxygen-barrier coating.
- a coated paper comprising a high-density paper according to the first aspect, wherein a surface of the high density paper is provided with a barrier coating, e.g. comprising polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), a starch or starch derivative, a nano or micro-fibrillar cellulose, polyvinylidene chloride (PVDC) or a polyamide.
- a preferred barrier coating comprises PVOH and/or EVOH, e.g. in an amount of 1-3 g/m 2 .
- the coated paper of the third aspect is not PECVD- or PVD-coated.
- the coated paper of the third aspect comprises several barrier layers, e.g. including one water vapor barrier layer.
- the coated paper of the third aspect may be used for packaging oxygen-sensitive products, such as dry and/or fatty foods.
- oxygen-sensitive products such as dry and/or fatty foods.
- fatty foods are cheese, butter and spreads.
- Such packaging may be flow-wrap packaging or form, fill, seal (FFS) packaging, e.g. in bags. It may also be packaging in ajar, tray, lidded spread container, collapsible tube, clam-shell package, sleeve, envelope or wrapper.
- Another application is use as a packaging window. In these applications, the packaging material typically undergoes folding or a similar type of stress (e.g. creasing, stretching), which make the packaging material based on the high-density paper of the present disclosure particularly suitable.
- a use of a multi-layered material for packaging of a food product or another oxygen-sensitive product wherein one layer of the multilayered material is a high-density paper according to the first aspect, provided that the food product is not a liquid, semi-liquid or viscous food product.
- liquid food includes water.
- the multi-layered material of the fourth aspect may comprise a coated paper according to the third aspect.
- the multi-layered material of the fourth aspect is not comprising a PECVD or PVD coating.
- Two pulps were provided: i) an ECF-bleached kraft pulp from softwood (i.e. a mixture of pine and spruce); and ii) an ECF-bleached kraft pulp from hardwood (i.e. birch).
- the softwood pulp was refined using high-consistency (HC) refiners at a specific energy of 225 kWh/tonne.
- HC high-consistency
- the HC-refined pulp was than mixed in a mixing chest with a broke pulp comprising a blend of bleached softwood and hardwood pulps (the majority of the broke was obtained from the same paper production).
- the share of broke in this softwood-based mixture was 30%.
- the softwood-based mixture was then refined by low-consistency (LC) refining at a specific energy of 75 kWh/tonne. This LC refining resulted in a Schopper-Riegler (°SR) according to ISO 5267-1:1999 of ⁇ 30 °SR.
- the hardwood pulp was separately mixed with the same type of broke and then refined by low consistency refining using a specific energy of 85 kWh/tonne.
- the share of broke in hardwood-based mixture was 20%.
- the LC-refined hardwood-based mixture obtained a Schopper-Riegler (°SR) value of ⁇ 38 °SR.
- papermaking chemicals were added (4 kg/tonne of cationic starch, 0.2 kg/tonne of silica and 0.4 kg/tonne of AKD).
- the softwood-based mixture was pumped to a bottom ply head box of a two-ply fourdrinier machine, while the hardwood-based mixture was pumped to the top ply head box of the same fourdrinier machine.
- the dry mass flow through each of the head boxes was the same and adjusted to reach a total grammage of 60 g/m 2 prior coating (i.e. 30 g/m 2 per ply).
- the vertical slice lip was 34 mm for the bottom ply head box and 16 mm for the top ply head box, which reflect relatively low head box consistencies (about 0.12% for the bottom ply and about 0.25% for the top ply).
- the wire speed was 600 m/min. In a paper machine specifically adapted for this product, the wire speed can be considerably higher.
- the two plies formed on the fourdrinier machine were couched together at a dryness of ⁇ 10% and further dewatered using vacuum foils boxes to ⁇ 20% dryness before being subjected to wet pressing in a press section having two single felted press nips, wherein the first press had the felt on the top side and the second press had the felt on the bottom side.
- the web was dried in a conventional multi-cylinder dryer to form a paper substrate having a moisture content of ⁇ 5%.
- the paper substrate Prior winding up, the paper substrate was calendered in a soft nip at a line load of 20 kN/m. Properties of the paper substrate are presented in table 1 below.
- FIG. 1A A SEM image of a surface portion of the paper substrate is shown in figure 1A .
- the paper substrate from 1A was off-line impregnated with an aqueous polyvinyl alcohol (PVOH) composition from both sides in a conventional film press.
- PVOH polyvinyl alcohol
- the type of PVOH was Poval 10/98 (Kuraray) and its concentration in the composition was 10% (in another trial, the concentration was instead 8%, which also worked).
- the composition further comprised glyoxal (Cartabond TSI) in an amount of 6 wt.% compared to the amount of PVOH.
- the glyoxal acted as a cross-linker.
- the viscosity of the composition was 74 mPa*s (measured at 60 °C).
- the applied amount of PVOH was 1 g/m 2 on the top side and 2 g/m 2 on the reverse/bottom side.
- the reason for using a higher amount of PVOH for the reverse/bottom side was that the pulp used for forming the bottom ply had a lower SR number (and hence that the reverse/bottom side had a less dense surface compared to the top side).
- the PVOH-impregnated paper substrate was dried using hot air to a moisture content of about 8%. Properties of the dried PVOH-impregnated paper substrate are presented in table 1 below.
- Figure 1B is a SEM image of a surface portion of the PVOH-impregnated paper substrate. As shown in figure 1B , the PVOH has not formed a film on the surface portion. Instead, it has penetrated into the fiber web.
- the applied amount of PVOH was 1.5 g/m 2 on each side instead of 1 g/m 2 on the top side and 2 g/m 2 on the reverse/bottom side.
- the impregnated paper substrate from 1B was re-moisturized to 15%.
- the re-moisturized paper was fed to an off-line multi-nip calender also referred to as a supercalender (the number of nips was 12).
- Supercalendering was carried using a surface temperature of 140 °C on the thermo rolls, which could be obtained by means of outside induction heaters, to obtain a high-density paper.
- the line load in each nip was 450 kN/m.
- the total supercalendering nip impulse was ⁇ 800 kPa ⁇ s [#nips ⁇ line load / web speed].
- the heating from the thermo rolls dried the high-density paper.
- FIG 1C A SEM image of a surface portion of the high-density paper is shown in figure 1C .
- figure 2 is SEM image of a cross section 20 of the high-density paper.
- the dark grey areas 21 are PVOH and light grey areas 22 are fibers.
- figure 2 shows that most of the PVOH is within the fiber web. Only minor portion of the PVOH is found on the surface.
- MG machine glazed
- Grammage was measured according to ISO 536:2012 and has the unit g/m 2 .
- Density was measured according to ISO 534:2011 and has the unit kg/m 3 .
- Roughness means Bendtsen roughness, was measured according to ISO 8791-2:2013 and has the unit ml/min.
- Tensile index was measured in the MD and the CD according to ISO 1924-3:2005 and has the unit Nm/g.
- Tear index was measured in the MD and the CD according to ISO 1974:2012 and has the unit mNm 2 /g.
- °SR was measured according to ISO 5267-1:1999 after repulping according to ISO 5263-1:2004.
- CSF Canadian Standard Freeness
- CSF Canadian Standard Freeness
- Fines content was measured with a L&W Fibretester+ (ABB, Lorentzen & Wettre, Sweden) after repulping according to ISO 5263-1:2004. Fines are defined as fibrous particles shorter than 0.2 mm.
- “Somerville residue” means residues retained in a Somerville shive and flake content analyzer having a slot plate width of 0.15 mm. The residue content was calculated as dry weight-% of originally introduced dry material (into the re-pulper).
- Oxygen Transmission Rate has the unit cm 3 /m 2 /24h, 0.2 atm (21%) oxygen. It was measured according to ASTM F1927-14 after lamination with 20 g/m 2 LDPE on the top side of the paper.
- Super Perga 1 and 2 are commercial greaseproof papers from Nordic Paper. Super Perga 1 was used as a paper substrate in WO 2017/089508 . Table 1. Paper substrate (1A) PVOH-impreg. paper substrate (1B) High-density paper (1C) Ref. SC paper (1D) Ref. SC MG paper (1E) Ref.
- Valmet repulping method Repulping was carried out in a Valmet repulper that is designed for stock preparation, i.e. fiber disintegration, of the type HD400. Agitation was done with an impeller with three radial and serrated blades with the dimensions 30 by 40 mm rotating at a speed of 3000 rpm. The material to be repulped was cut in 90 by 90 mm pieces. 0.5 kg of air-dried pieces was mixed with 10 liters of water, i.e. to a consistency of 5%, and repulped at 2.5 minutes at a temperature of 57 °C. Then 5 liters of water was added, providing a consistency of 3.3 %, and further repulping at another 17.5 minutes at a temperature of 57 °C was performed. Total repulping time was thus 20 minutes.
- Somerville method The Valmet repulping method described above was first carried out to obtain a pulp. Quantification of the proportion of Somerville residues, as retained in Somerville shive and flake content analyzer with slot plate width 0.15 mm, was made by diluting the pulp to less than 1 % consistency. The diluted pulp was then analyzed in the Somerville analyzer to obtain the proportion of flake residues as weight-% calculated on oven dry material (i.e. moisture content 0%), initially introduced into the repulping operation.
- oven dry material i.e. moisture content 0%
- the single-ply paper was made from a pulp mixture comprising Kraft softwood pulp, Kraft hardwood pulp and a smaller amount of CTMP pulp, in an approximate dry weight ratio of 45:45:10.
- the single-ply paper had been impregnated with PVOH from the top side and subsequently supercalendered to a density of about 1100 kg/m 3 .
- the grammage of the single-ply paper was 57 g/m 2 .
- the top-side surface had a smoothness of 15 ml/min Bendtsen.
- a non-impregnated reference paper was provided. It had a top side surface smoothness of about 20 ml/min Bendtsen, a grammage of 39 g/m 2 and a density of 978 kg/m 3 .
- the single-ply paper and the non-impregnated reference paper were coated twice with 1 g/m 2 of PVOH onto the top side of the paper substrate and dried after each coating operation. They were then laminated to packaging materials having the following layer structure: /LDPE 12 g/m 2 /paperboard (80 mN geometric bending resistance)/LDPE 20 g/m 2 /paper substrate with 2 ⁇ PVOH á 1 g/m 2 /Adh EAA copolymer 6 g/m 2 /blend LDPE+m-LLDPE 19 g/m 2 /
- the oxygen transmission of the laminated materials was measured by a fluorescent method using an oxygen probe PSt9 from PreSens GmbH, Germany. According to this method, a flat sample to be analyzed is placed on a cell, which is flushed with dry nitrogen, in which the probe is also located. The area of the circular cell section is 68 cm 2 (0.0068 m 2 ). The surface of the sample that is not directed towards the cell is facing ambient air, i.e. 21 % oxygen, at 23 °C and 50 % RH. By using the oxygen concentration reading from the probe, an oxygen transmission rate is calculated according to ASTM F3136-15. The unit is provided as ml/specimen.
- the oxygen barrier properties of a planar material may be investigated before and after having been folded and then unfolded.
- the folding angle was 165 degrees and the barrier layer was directed to be on the outside of the fold. Measured values are the average of five samples measured.
- FIG 3 shows that the unfolded laminated packaging material comprising the PVOH-coated (non-impregnated) reference paper substrate provides an oxygen barrier.
- This oxygen barrier is however lost after one round of folding and unfolding.
- the oxygen barrier provided by the laminated packaging material comprising the impregnated paper is much less affected by the folding-unfolding action.
- This "folding resistant" oxygen barrier is an important property since the laminate will be folded in the packaging process.
- the high-density paper obtained in Example 1C above was coated twice with intermediate and subsequent drying operations to provide a PVOH coat weight of 3 g/m 2 and then metalized to an optical density of about 2.
- a laminated packaging material was then produced according to the following layer structure: /LDPE 12 g/m 2 /paperboard (80 mN geometric bending resistance)/LDPE 20 g/m 2 / high-density paper+PVOH+met./Adhesive EAA copolymer 6 g/m 2 + 29 g/m 2 blend LDPE + mLLDPE /
- Packages were produced in a Tetra Pak ® E3/CompactFlex filling machine. This type of filling machine has the capacity to fill portion packages at a speed of 9000 packages/hour and a flexibility that allows for quick change between different package formats. Packages were in the format of Tetra Brik ® with a volume of 200 ml.
- Laminates comprising a PVOH-coated greaseproof paper from Nordic Paper, identified as "Super Perga ® WS Parchment” and having a grammage of 32 g/m 2 , were used as comparative examples:
- Oxygen transmission rate (OTR) of flat packaging material was measured using a coulometric detector according to the standard ASTM F1927-14.
- the relative humidity (RH) was either 50% or 80%.
- the unit was cm 3 /m 2 /24h, with the option of using 0.2 atm or 1 atm of oxygen pressure. To be able to compare OTR values measured at 1 atm with OTR values measured at 0.2 atm, the former values can be multiplied with 0.2.
- the oxygen transmission rate (OTR) of packages was measured according to ASTM F1307-14, at 0.2 atm (surrounding air containing 21 % oxygen). The unit is cm 3 /package/24h. The OTR testing was carried out 2-3 weeks after production of the filled and sealed packages.
- the package was mounted on a special holder; inside the package nitrogen was purged; the outside of the package is exposed to the environment surrounding the instrument.
- oxygen permeated through the package into the nitrogen carrier gas it was transported to the coulometric sensor.
- the sensor read how much oxygen that was leaked into the nitrogen gas inside the package.
- the filled 200 ml package made from the laminate comprising the impregnated high-density paper according to the present disclosure has a very low level of oxygen transmission (0.03 cm 3 /m 2 /day/0.2 atm at 23 °C and 50%RH). Furthermore, the oxygen barrier remained as effective in a more humid environment (23 °C and 80 % RH). In the reference laminate comprising the Super Perga paper substrate, the OTR value was 0.075 at 23°C and 50%RH, which means 2-3 times shorter shelf life for an oxygen sensitive product in a 200 ml package. It is thus shown that the impregnated high-density paper according to the present disclosure enables a higher fiber-based content in a packaging material for packaging of oxygen-sensitive products.
- the OTR of a laminate based on the impregnated high-density paper according to the present disclosure is at least as good as similar paper-based barrier laminates of the prior art. Most importantly, it does not exhibit the same level of loss of oxygen barrier properties when converted into a filled, formed and heat-sealed packaging container. It is thus shown above that the impregnated high-density paper according to the present disclosure provides a robustness against the stresses that a packaging material typically experiences during conversion and use.
- the proportion of coarse reject i.e. the non-fibrous recyclable part of the laminated materials (polymers, aluminum foil and some non-detachable fibers), was determined after re-pulping by a Valmet re-pulper.
- the re-pulping was carried out in the same way as described above in connection with CSF and Somerville measurements, except that the laminated packaging material to be re-pulped and analyzed was first cut into pieces of 30 by 90 mm.
- the coarse reject was screened (separated) using a plate with holes (diameter: 10 mm) and then dried to 0% moisture content.
- the proportion of coarse reject was then calculated as weight percent of dry (0% moisture) material introduced into the re-pulper.
- the coarse reject as determined by a contracted global industrial supplier of equipment for fiber processing and recycling was made in a similar way.
- 20 g of laminated material was mixed into 21 of water and disintegration was carried out at a consistency of about 1% for time cycles of 18 minutes.
- the water temperature was kept at 57 °C also in this test.
- Table 3 Laminate Reference laminate comprising a 6.3 ⁇ m aluminum foil ⁇ Reference laminate comprising 38 g/m 2 Super Perga paper coated with 1 g/m 2 PVOH and metallized to OD 2.5 ⁇ Laminate comprising the HD paper of example 1C coated with 3 g/m 2 PVOH and metallized to OD ⁇ 2 ⁇ Coarse reject (wt-%) as repulped by Valmet re-pulper, 20 min 29 - 26 (18 after 50 minutes) Coarse reject (wt-%) as re-pulped by the alternative method 39.8 40.2 - ⁇ /LDPE 12 g/m 2 /paperboard (80 mN geometric bending resistance)/LDPE 20 g/m2/Al-foil 6.3 ⁇ m/Adhesive EAA copolymer 6 g/m 2 + 19 g/m 2 blend LDPE + mLLDPE/ ⁇ /LDPE 12 g/m 2 /paperboard
Claims (15)
- Hochdichtes Papier mit einer gemäß ISO 536:2012 gemessenen Grammatur von 30-75 g/m2 und einer gemäß ISO 534:2011 gemessenen Dichte von über 1000 kg/m3, wobei das hochdichte Papier auf jeder Seite mit 0,3-4,0 g/m2, beispielsweise 0,5-3,0 g/m2, eines Polymers imprägniert ist, das aus der Gruppe ausgewählt ist, die aus Polyvinylalkohol (PVOH), Ethylenvinylalkohol (EVOH), carboxymethylierter Cellulose (CMC), nanokristalliner Cellulose (NCC) und Carboxymethylstärke (CMS) besteht.
- Hochdichtes Papier nach Anspruch 1, das zu mindestens 50 % des Trockengewichts aus Kraftzellstoff, beispielsweise zu mindestens 75 % des Trockengewichts aus Kraftzellstoff, beispielsweise zu mindestens 85 % des Trockengewichts aus Kraftzellstoff, beispielsweise zu mindestens 95 % des Trockengewichts aus Kraftzellstoff gebildet ist.
- Hochdichtes Papier nach Anspruch 1 oder 2, wobei 20-65 % des Trockengewichts, beispielsweise 30-60 % des Trockengewichts, des zur Bildung des hochdichten Papiers verwendeten Zellstoffs Hartholzzellstoff ist.
- Hochdichtes Papier nach einem der vorhergehenden Ansprüche, wobei 35-80 % des Trockengewichts, beispielsweise 40-70 % des Trockengewichts, des zur Bildung des hochdichten Papiers verwendeten Zellstoffs Weichholzzellstoff ist, vorzugsweise Weichholz, das einer Hochkonsistenzveredelung (HC) unterzogen wurde.
- Hochdichtes Papier nach einem der vorhergehenden Ansprüche mit einer oberen Lage und einer unteren Lage.
- Hochdichtes Papier nach einem der vorhergehenden Ansprüche, wobei die Grammatur, gemessen gemäß ISO 536:2012, 35-65 g/m2, beträgt.
- Hochdichtes Papier nach einem der vorhergehenden Ansprüche, das nach einem Wiederaufbereiten gemäß ISO 5263-1:2004 eine gemäß ISO 5267-1:1999 gemessene Schopper-Riegler-Zahl (°SR) von 33-50, beispielsweise 35-45, aufweist.
- Hochdichtes Papier nach einem der vorhergehenden Ansprüche, das nach einem Wiederaufbereiten gemäß ISO 5263-1:2004 einen mit einem L&W Fibretester+ (ABB, Lorentzen & Wettre, Schweden) gemessenen Feinanteil von weniger als 40 %, beispielsweise weniger als 34 %, beispielsweise weniger als 32 %, aufweist, wobei Feinanteile als faserige Partikel, die kürzer als 0,2 mm sind, definiert sind.
- Verfahren zur Bildung eines hochdichten Papiers mit einer gemäß ISO 536:2012 gemessenen Grammatur von 30-75 g/m2 und einer nach ISO 534:2011 gemessenen Dichte von über 1000 kg/m3, wobei das Verfahren die Schritte aufweist:- Imprägnieren jeder Seite eines Papiersubstrats mit 0,3-4,0 g/m2, beispielsweise 0,5-3,0 g/m2, eines Polymers, ausgewählt aus der Gruppe bestehend aus Polyvinylalkohol (PVOH), Ethylenvinylalkohol (EVOH), carboxymethylierter Cellulose (CMC), nanokristalline Cellulose (NCC) und Carboxymethylstärke (CMS), um ein imprägniertes Substrat zu erhalten; und- Superkalandrieren des imprägnierten Substrats, um das hochdichte Papier zu erhalten.
- Verfahren nach Anspruch 9, wobei das Polymer PVOH mit einem gewichtsmittleren Molekulargewicht (Mw) unter 100000 g/mol ist.
- Verfahren nach Anspruch 9 oder 10, wobei der Imprägnierungsschritt Hinzufügen einer wässrigen Zusammensetzung, die das Polymer aufweist, zu jeder Seite des Papiersubstrats aufweist, und die bei 60°C gemessene Viskosität der wässrigen Zusammensetzung 55-90 mPa*s beträgt.
- Verfahren nach einem der Ansprüche 9-11, wobei das imprägnierte Substrat, das in den Superkalandrierungsschritt eintritt, einen Feuchtigkeitsgehalt von 11,0 %-20,0 %, vorzugsweise 12,0 %-19,0 %, noch bevorzugter 13,5 %-18,0 %, aufweist.
- Verfahren nach einem der Ansprüche 9-12, wobei der Imprägnierungsschritt mittels einer Filmpresse durchgeführt wird.
- Beschichtetes Papier, aufweisend ein hochdichtes Papier nach einem der Ansprüche 1-8, wobei eine Oberfläche des hochdichten Papiers mit einer Barrierebeschichtung versehen ist, die Polyvinylalkohol (PVOH), Ethylenvinylalkohol (EVOH), Stärke oder Stärkederivat, nano- oder mikrofibrilläre Cellulose, Polyvinylidenchlorid (PVDC) oder ein Polyamid aufweist.
- Verwendung eines mehrschichtigen Materials zum Verpacken eines Lebensmittelprodukts oder eines anderen sauerstoffempfindlichen Produkts, wobei eine Schicht des mehrschichtigen Materials ein hochdichtes Papier nach einem der Ansprüche 1-8 ist, insofern das Lebensmittelprodukt kein flüssiges, halbflüssiges oder viskoses Lebensmittelprodukt ist.
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EP21168232.3A EP4074891B1 (de) | 2021-04-13 | 2021-04-13 | Neues substrat |
FIEP21168232.3T FI4074891T3 (fi) | 2021-04-13 | 2021-04-13 | Uusi substraatti |
BR112023020997A BR112023020997A2 (pt) | 2021-04-13 | 2022-04-13 | Papel de alta densidade, método para formar um papel de alta densidade, papel revestido e uso de um material multicamadas para embalagem de um produto alimentar ou outro produto sensível ao oxigênio |
PCT/EP2022/059874 WO2022219043A1 (en) | 2021-04-13 | 2022-04-13 | New substrate |
CN202280024783.XA CN117222793A (zh) | 2021-04-13 | 2022-04-13 | 新基材 |
EP22722738.6A EP4323584A1 (de) | 2021-04-13 | 2022-04-13 | Neues substrat |
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EP21168232.3A EP4074891B1 (de) | 2021-04-13 | 2021-04-13 | Neues substrat |
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CN (1) | CN117222793A (de) |
BR (1) | BR112023020997A2 (de) |
FI (1) | FI4074891T3 (de) |
WO (1) | WO2022219043A1 (de) |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE532388C2 (sv) * | 2008-03-14 | 2010-01-12 | Tetra Laval Holdings & Finance | Förpackningslaminat och -behållare med två separata gasbarriärskikt samt metod för deras framställning |
BR112012000275B8 (pt) | 2009-07-08 | 2020-06-23 | Tetra Laval Holdings & Finance | laminado de acondicionamento, métodos para fabricar e para termosselar um laminado de acondicionamento, e, recipiente de acondicionamento |
EP4105013B1 (de) | 2015-11-27 | 2024-01-31 | Tetra Laval Holdings & Finance S.A. | Laminiertes verpackungsmaterial, daraus hergestellte verpackungsbehälter |
-
2021
- 2021-04-13 EP EP21168232.3A patent/EP4074891B1/de active Active
- 2021-04-13 FI FIEP21168232.3T patent/FI4074891T3/fi active
-
2022
- 2022-04-13 EP EP22722738.6A patent/EP4323584A1/de active Pending
- 2022-04-13 WO PCT/EP2022/059874 patent/WO2022219043A1/en active Application Filing
- 2022-04-13 CN CN202280024783.XA patent/CN117222793A/zh active Pending
- 2022-04-13 BR BR112023020997A patent/BR112023020997A2/pt unknown
Also Published As
Publication number | Publication date |
---|---|
BR112023020997A2 (pt) | 2023-12-12 |
EP4323584A1 (de) | 2024-02-21 |
EP4074891A1 (de) | 2022-10-19 |
CN117222793A (zh) | 2023-12-12 |
FI4074891T3 (fi) | 2024-03-15 |
WO2022219043A1 (en) | 2022-10-20 |
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