Corrugated board comprising a polymer coated liner

Abstract

The present invention relates to a corrugated board comprising at least one liner and at least one corrugated medium, wherein said at least one liner comprises a first polymer coating layer formed by extrusion coating of a furandicarboxylic acid (FDCA) based resin onto at least one surface of the liner characterized in that the FDCA based resin comprises at least 50 % by weight of a FDCA based polymer. The present invention also relates to a method for producing said corrugated board.

Description

[0001] CORRUGATED BOARD COMPRISING A POLYMER COATED LINER

[0002] Technical field

[0003] The present invention relates to a corrugated board comprising at least one liner coated with a FDCA based resin.

[0004] Background

[0005] Corrugated board (sometimes referred to as corrugated cardboard or corrugated fiberboard) is a packaging material which can be converted to different types of packages. Corrugated board is a fiber based material made from cellulose fibers. The fibers can be virgin fibers or recycled fibers, such as fibers from used corrugated cardboard or other materials.

[0006] The corrugated board comprises at least one corrugated medium (fluting) and at least one non-corrugated medium (liner or linerboard) glued onto a surface of the corrugated medium. For example, the corrugated board may consist of a layer of fluting glued between two layers of liner to form a sandwich structure. The sandwich structure can be formed in different ways such as in single, double, and triple walls as described, e.g., in Kirwan M., J., Paper and Paperboard. Packaging Technology, Blackwell Publishing 2005.

[0007] There are different kinds of corrugated board qualities, and these may comprise different types of liners and corrugated media. Containerboard (also known as CCM or corrugated case material) is a type of paperboard specially manufactured for the production of corrugated board. It includes both linerboard and corrugating medium (or fluting), the two types of paper that make up corrugated board. Since containerboard is made mainly out of natural unbleached wood fibers, it is generally brown, although its shade may vary depending on the type of wood, pulping process, recycling rate and impurity content.

[0008] Examples of different types of liners are kraftliner, white top liner and testliner. Kraftliner is typically produced from kraft pulp that can be bleached or unbleached, but also mechanical pulp or semi-chemical pulp, and may comprise one or more layers / plies wherein the top layer / ply is often optimized to provide a good printing surface and good moisture resistance. Testliner is mainly produced from recycled fiber such as old corrugated carton or board, so called OCC, and is commonly manufactured in two layers / plies. Due to the presence of recycled fibers, testliner may typically have lower mechanical strength, particularly lower burst strength, than kraftliner. Kraftliner is frequently used in packaging boxes with higher demands on strength properties.

[0009] Corrugated medium is formed from paper or paperboard which has been corrugated using heat, moisture and pressure using a corrugator.

[0010] One important challenge when making corrugated medium and corrugated board is the resistance to humidity. When the corrugated board is exposed to humidity, water and water vapor may diffuse through the liners and soften the corrugating medium. A common solution to this problem is to increase grammage of the fluting and / or liner, but this is in conflict with environmental demands requiring lower grammage materials consuming less raw material.

[0011] Another solution is to provide a barrier layer on the liner to reduce the penetration of oil, fat,, grease, water and water vapor. Barrier layers typically reduce the recyclability of the materials and it also make the material less sustainable.

[0012] Extrusion coating is a process by which a molten polymer material is applied to a substrate, such as paper or paperboard to form a very thin, smooth and uniform coating layer. The coating can be formed by the extruded polymer itself, or the molten polymer can be used as an adhesive to laminate a solid polymer film onto the substrate. Common polymer resins used in extrusion coating include polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). A big disadvantage with these polymers, such as PE and PET is that they are fossilbased polymers and their production and disposal have negative environmental impacts. There is therefore a need to find more sustainable polymers when making polymer coated paper or paperboard. Also, many of these polymer materials does not withstand too high temperatures. Polyethylene terephthalate (PET) has many interesting properties and multiply uses such as for frozen food and heated food products including both microwave oven and oven. Despite its thermal stability, the PET polymer might lose barrier properties when exposed to heat and moisture, due to for example chain relaxation but also due to hydrolysis.

[0013] Thus, polyethylene terephthalate (PET) may show hydrolytic degradation under high temperature and moist conditions, which leads to reduced barrier properties and mechanical properties.

[0014] Furandicarboxylic acid (FDCA) based polymers are a more sustainable polymer options since these are derived from renewable sources, such as vegetable or plant-based feedstocks like wood, sugarcane, sugar beet, or other agricultural crops or residues. These are then converted to saccharides such as fructose or glucose and then to intermediates before obtaining the FDCA. This bio-based origin of FDCA based polymers makes it more environmentally friendly.

[0015] One challenge with the use of FDCA based polymers, such as polyethylene furanoate (PEF), as a coating layer, is to have sufficient adhesion between the polymer layer and the paper or paperboard. Also, there is a need for the FDCA based polymer to have good dimensional stability to make it stable during extrusion and also after heating.

[0016] Consequently, there is need for a new and improved corrugated board that combine low grammage, improved water / moisture resistance and that is more sustainable. Also, a corrugated board with improved mechanical properties when stacking boxes comprising wet or frozen food. Furthermore, there is a need to provide barrier coated liner which has improved thermal and mechanical properties and good runnability in a corrugator.

[0017] Description of the invention

[0018] It is an object of the present disclosure to provide a corrugated board which solves or ameliorates at least some of the above mentioned problems. It is a further object of the present disclosure to provide a corrugated board with improved barrier properties.

[0019] It is a further object of the present disclosure to provide a corrugated board that is more sustainable.

[0020] It is yet a further object of the present disclosure to provide an improved method for the manufacturing of a corrugated board which solves or ameliorates at least some of the above mentioned problems.

[0021] The above-mentioned objects, as well as other objects as will be realized by the skilled person in the light of the present disclosure, are achieved by the various aspects of the present disclosure.

[0022] According to a first aspect illustrated herein, there is provided a corrugated board comprising at least one liner and at least one corrugated medium, wherein said at least one liner comprises a first polymer coating layer formed by extrusion coating of a furandicarboxylic acid (FDCA) based resin onto at least one surface of the liner wherein the FDCA based resin comprises at least 50 % by weight of a FDCA based polymer.

[0023] It has been found that by coating a liner with a FDCA based resin it is possible to provide a corrugated board with improved barrier properties and that is more sustainable. The coated corrugated can also be produced at a lower grammage and with improved mechanical properties. The corrugated board has been found to be able to package many grease and fat products, such as pizza, bakery products, fresh food products, including fish and berries as well as frozen food products.

[0024] In some embodiments, the FDCA based resin comprises at least 70 % by weight, preferably at least 90 % by weight, of the FDCA based polymer. The FDCA based resin of the invention may also consist, or substantially consist, of the FDCA based polymer. For some end use, it is preferred that the FDCA resin consists, or substantially consists, of the same FDCA polymer since such mono-material coating is easier to recycle.

[0025] The FDCA based polymer preferably has a melting temperature above 170 °C, preferably above 190 °C, the melting temperature is preferably between 170-270 °C and even more preferred between 190-255 °C, preferably between 200-225 °C. The melting temperature is determined by differential scanning calorimetry according to standard ASTM D3418-21 . In order for the coated liner to be able to cope the corrugated production process, it needs to be able to withstand heat treatment, for example if pre-heating and condition of the liner prior to attachment of the corrugated medium, and afterwards when attaching the corrugated medium which has a high temperature after being conducted through the corrugator. The process might further include additional drying or curing steps, including steam treatment. It is therefore necessary for the FDCA based polymer to be stable after being subjected to such heat or steam treatment. With stable is meant that the FDCA based polymer both is mechanically stable and having maintained barrier properties even after heat and / or steam treatment. The barrier properties, such as grease barrier, water vapor transmission rate and oxygen transmission rate should be at a good value, i.e. not deviating more than 20% from the original value, preferably not more than 15% from the original value, at least 2 weeks after heat treatment, preferably after 4 weeks. The high thermal stability is thus important for it to be able to manage the high temperatures during the production of the corrugated board. However, a drawback with the high melting temperature is that the adhesion properties of the polymer is reduced.

[0026] The FDCA based polymer preferably has an intrinsic viscosity of less than 0.9 dl / g, preferably between 0.5-0.9 dl / g, as determined according to ISO 1628. It has been found that the use of a FDCA based polymer with the mentioned intrinsic viscosity will improve the bonding of the FDCA based resin to the liner and the runnability of the polymer in the extruder. It is also believed that the FDCA based polymer with the lower intrinsic viscosity would be less prone to degradation compared other polymers such as PET. It has been found that by using a specific type of FDCA based polymer with a low intrinsic viscosity and high melting temperature, the minimum grammage of FDCA based resin required to achieve sufficient adhesion and stability of the film formation in extrusion coating of the liner can be reduced. At the same time the dimensional stability and / or rigidity is improved. To have a good adhesion is crucial in many converting operations.

[0027] The FDCA based polymer preferably has a crystallinity of between 5-40%, preferably between 10-35% and even more preferred between 15-25%. Crystallinity is measured according to ASTM E794-06 (2018). Low crystallinity is preferred since it will improve heat or ultrasonic sealability properties and adhesion of the FDCA based polymer. Also, the stability, stretchability and barrier properties has also been found to improve for FDCA based polymers having a lower crystallinity.

[0028] In some embodiments, the FDCA based resin also comprises a FDCA based polymer having an intrinsic viscosity of 0.9 dl / g or higher, as determined according to ISO 1628. In some embodiments, the FDCA based resin comprises 1-50 % by weight of a FDCA based polymer having an intrinsic viscosity 0.9-1 .2 dl / g, as determined according to ISO 1628. It can be an advantage to use a mixture of FDCA based polymers having different intrinsic viscosity. FDCA based polymers with a higher intrinsic viscosity will contribute to improved mechanical and barrier properties of the polymer coating.

[0029] The formulation of a resin used for coating may vary greatly depending on the intended use of the coated linerboard. The FDCA based resin may include a wide range of ingredients in varying quantities to improve the end performance of the product or processing of the coating. The FDCA based resin can also comprise other polymeric or non-polymeric coating components. In other words, the FDCA based resin can be a blend of the FDCA based polymer and another polymer. The FDCA based resin preferably comprises at least one additional component selected from the group consisting of a polymer other than a FDCA based polymer, a colorant, (e.g. Titanium dioxide or carbon black), a dye, a filler or a pigment (e.g. CaCOs or talc). The FDCA based resin my also comprise other additives such as lubricants, slip agents, plasticizers, antioxidants and / or UV stabilizers.

[0030] The term coating, as used herein, refers to an operation in which the surface of a substrate is covered with a composition to impart a desired properties, finish or texture to the substrate. The coating can be applied to one side or both sides of the liner. It is preferred that the coating is only applied to one side of the liner. The coating may be added by extrusion coating or lamination. In some embodiments the first coating layer is the only coating layer applied to the liner. In some embodiments the first coating layer is a single coating layer. In some embodiments the first coating layer is a multiply coating layer. The first coating layer is preferably located on the inside and / or outside of the corrugated board

[0031] The liner may also comprise at least one second coating layer disposed on top of the first coating layer. It may be preferred to add more than one coating layer on the liner to form a multilayer coating. The second coating layer can have the same composition as the first coating layer. As the FDCA based coating layer provides good stability of the film formation and adhesion of the FDCA based resin to the liner, it may preferably be used as the first (or innermost) coating layer applied directly onto the liner surface. The extrusion coated FDCA based coating layer may serve to promote adhesion of subsequently applied or coextruded polymeric coating layers. The extrusion coated FDCA based coating layer may serve as an adhesive for a polymeric film in an extrusion film lamination process.

[0032] In some embodiments, the liner extrusion coated with the FDCA based resin, further comprises at least one additional polymeric coating layer disposed on top of the extrusion coated FDCA based resin, wherein the additional polymeric coating layer has a composition different from the extrusion coated FDCA based resin.

[0033] It may be preferred that the second coating layer has a different composition than the first coating layer. The second coating layer preferably comprises a FDCA based polymer, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP) and / or polylactic acid (PLA). In a preferred embodiment, the at least one additional coating layer comprises polyethylene furanoate (PEF).

[0034] In some embodiments, the at least one additional coating layer is formed by extrusion coating or by extrusion film lamination.

[0035] The first and eventual second coating layer / s are preferably applied to the liner at a combined grammage of less than 60 gsm, preferably less than 50 gsm, more preferably less than 40 gsm, measured according to ISO 536. It may be preferred that the first and eventual second coating layer / s is applied in an amount of 10-60 gsm, preferably between 15-50 gsm and even more preferred between 20-40 gsm, measured according to ISO 536. It has been found that it is possible to add small amount of coating layer / s and still be able to achieve sufficient adhesion and stability of the film.

[0036] The FDCA based polymer is preferably polyethylene furanoate (PEF), polybutylene furanoate (PBF), polytrimethylene furandicarboxylate (PTF), polypentamehylene furanoate (PPeF), polyheamethylene furanoate (PHF) or polypropylene furanotate (PPF). It is preferred that the FDCA based polymer is polyethylene furanoate (PEF).

[0037] The corrugated board preferably has a grammage between 60-500 gsm, measured according to ISO 536, even more preferred between 150-350 gsm, preferably between 150-250 gsm. The the liner and / or corrugated medium preferably has a grammage between 20-250 gsm, preferably between 50-200 gsm and even more preferred between 80 and 150 gsm, measured according to ISO 536. It has been found that it is possible to reduce the grammage of the corrugated board and still be able to stable corrugated board having very good barrier properties.

[0038] The corrugated board preferably has a water vapor transmission rate (WVTR) below 50 g / m2 / day at 23 C / 50% RH measured according to ASTM D1249-20, preferably below 20 g / m2 / day at 23 C / 50% RH. By coating at least one liner with a FDCA based coating it was found that the water vapor resistance in the corrugated board was improved, even at lower grammages.

[0039] The coated side of the corrugated board preferably has less than 5 pinholes / m2, preferably less than 3 pinholes / m2, and more preferably less than 1 pinhole / m2, as determined according to EN13676:2001 . It is important that the FDCA based coating layer has very low amount of pinholes in order be able to provide a good barrier, especially good water, oil, fat or grease barrier.

[0040] The corrugated board preferably has a KIT value above 11 , preferably above 12, measured according to TAPPI T559. KIT is a value of grease resistance. It is important that the corrugated board has improved grease resistance.

[0041] The corrugated board preferably also has a fat resistance above 48 hours, preferably above 56 hours, according to the modified ASTM F119-82 method evaluated at 60 °C and 0% RH. It is important that the corrugated board has a very high fat resistance which makes it suitable for packaging greasy products, such as pizza, bakery products, fresh food products, including fish and berries as well as frozen food products.

[0042] The liner can be a kraftliner, testliner or a white top liner.

[0043] The liner may have a primer layer located between the liner and the first coating layer. The primer layer preferably has a grammage of 1-12 gsm, preferably 2-10 gsm. The primer layer will improve the adhesion of the first coating layer to the liner. It is preferred that the primer layer also is stable after heat treatment. The primer layer may comprise starch, carboxymethyl cellulose (CMC), m icrofibrillated cellulose, polyvinyl alcohol (PVOH), polyvinyl amine (PVAm), polyethylene imine (PEI), organosilanes, polyurethane, melamine, epoxy-based primers and / or acrylic co-polymers. It is also possible to add pigment into the primer layer to improve the light barrier properties.

[0044] The corrugated board according to the present invention comprises at least one liner and at least one corrugated medium. It may be preferred that the corrugated board comprises at least two liners and at least one corrugated medium. It is preferred that the corrugated medium is located between the at least two liners. It is preferred that only one of the at least two liners is coated with the first polymer coating layer. It is preferred that the first polymer coating layer is located on the outer side of the liner, i.e. the side not in contact with the corrugated medium. The other of the at least two liners may comprise at least one additional coating layer added to the side of the liner that is not in contact with the corrugated medium. The additional coating layer is preferably located on the outside on a package formed from the coated corrugated board. The additional coating layer may comprise a FDCA based polymer, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP) and / or polylactic acid (PLA).

[0045] According to a second aspect illustrated herein, there is provided a method for manufacturing a corrugated board, wherein said method comprises the steps of: providing a containerboard substrate, subjecting the containerboard substrate through a corrugator to form a corrugated medium, providing at least one liner, providing a FDCA based resin, applying the FDCA based resin onto the at least one liner by extrusion coating to form a first coating layer, applying an adhesive to at least one surface of the corrugated medium, attaching said corrugated medium to said liner in such way that the adhesive is located between the corrugated medium and the liner to form the corrugated board, wherein the FDCA based resin comprises at least 50 % by weight of a FDCA based polymer.

[0046] The containerboard substrate used to form the corrugated medium and the liner can be a single or multiply structure being manufactured in a paper or paperboard machine adapted for manufacturing of multiply containerboard. The containerboard substrate and / or liner can be a multiply structure. Paper or paperboard machines for making containerboard are well known in the art. Typically, the machine layout comprises a stock handling section, a wet end section, a pressing and drying section and optionally a calendaring and / or coating section. In the wet end section, the ply or plies may be formed individually, using different headboxes and laminated in a wet state, or formed together in a multiply headbox. If formed individually, the plies are typically laminated before the press and drying section of the paper machine. The method may further comprise the step of pre-heating the liner to a temperature of at least 100 °C, or more preferably at least 120 °C, and more preferably at least 140 °C, before the liner is attached to the corrugated medium. The pre-heating is preferably done by steam and / or heat. It is preferred that the liner is coated with the FDCA based coating before pre-heating and formation of the corrugated board. It is therefore crucial for the FDCA based polymer to be able to withstand high temperatures and to be thermally stable. It has been found that the FDCA based coating according to the invention is thermally stable and would provide the liner and thus the corrugated board with good barrier properties, especially moisture and grease resistance, also after being subjected to the formation of the corrugated board.

[0047] There are many advantages to be able to provide the liner with the barrier coating, e.g. the FDCA based coating, before formation of the corrugated board. It is much more cost efficient, and it also reduced the delamination risk.

[0048] The FDCA based resin may also be applied to the liner after the corrugated board is formed.

[0049] The method may also comprise the step of cooling the first coating layer in a chill roll at a temperature of between 5-60 °C for a time of at least 0.15 s, preferably between 0.15-10 seconds after extrusion coating. It may be possible to use more than one chill roll placed subsequent of each other during the cooling step. It is important to cool the extruded FDCA resin for a sufficient time, especially when extruding a FDCA based polymer, in order to achieve sufficient adhesion to the liner.

[0050] The corrugator is preferably operated at a temperature above 125°C, preferably between 125-190 °C. The high temperature is needed in order to be able to corrugate the containerboard substrate. Since the process for making corrugated board is done at a high temperature it has been found that the use of a FDCA based resin is especially suitable as a coating in corrugated board since it is stable at high temperatures and also after being subjected to high temperatures. The FDCA based coated liner is normally not treated in the corrugator. However, the attachment of the liner to the formed corrugated medium is normally done in-line close to the corrugator which means that the corrugated medium still has a high temperature when the liner is attached.

[0051] The method may further comprise the step of drying the liner to a moisture content of between 5-14 % by weight before application of the FDCA based coating, preferably between 8-11 % by weight. The moisture content is measured according to ISO 287. By reducing the moisture content of the liner it is possible to improve the adhesion of the coating layer to the liner. It is also important that the surface moisture content of the liner is controlled so that it is not too low. Too low moisture content will make the liner more brittle and not as stretchable and consequently less suitable for forming packages.

[0052] It is also important to control the moisture of the corrugated medium and / or liner(s) during the formation of the corrugated board. Too high or too low moisture will cause problem with curl and warp.

[0053] The corrugated medium and liner(s) are attached to each other by arranging an adhesive between the corrugated medium and liner(s). The liner is attached to at least one surface of the corrugated medium by the adhesive. The adhesive is preferably applied on a least one surface of the fluted corrugated medium and the liner is thereafter attached to said surface. Any conventional adhesives in the area may be used. The adhesive may for example be a glue that is based on starch that can be extracted from a wide variety of plants. Some of the most common plants are maize, wheat, barley, rice, potato, tapioca and peas. The starch is preferably native, i.e. no modification of the starch has been done. The adhesive may also comprise water, sodium hydroxide and cross-linker such as MFC or boric acid. Other additives, such as additives to improve the wet strength or adhesive bond strength may also be added. Also, other functional chemicals in order to improve e.g. moisture resistance or gelling behavior can be added, e.g. borax, glyoxal or mixtures thereof. The adhesive is preferably a starch-based adhesive. The corrugated medium and / or liner comprises cellulosic pulp. The cellulosic pulp may be hardwood pulp or softwood pulp, or a mixture thereof. The hardwood may for example be aspen, alder, poplar, eucalyptus, birch, acacia, or beech. Softwood pulp may for example be spruce or pine. The cellulosic pulp may be chemical pulp, mechanical pulp, thermomechanical pulp or chemi-thermomechanical pulp (CTMP). The cellulosic pulp may preferably be neutral sulfite semi chemical (NSSC) pulp. The cellulosic pulp may be bleach or unbleached pulp. The cellulosic pulp may comprise virgin and / or recycled fibers.

[0054] The corrugated medium and / or liner(s) may comprise an internal sizing agent. The internal sizing agent is preferably a hydrophobizing sizing agent. In some embodiments, the internal sizing agent is selected form the group consisting of alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), rosin sizes, and mixtures thereof. By adding an internal sizing agent the water and moisture resistance is improved.

[0055] Unless otherwise stated, the unit “% by weight” mentioned in the present disclosure refers to % by weight of the total dry weight of the relevant layer, composition, resin or the like.

[0056] While the invention has been described with reference to various exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

CLAIMS1 . A corrugated board comprising at least one liner and at least one corrugated medium, wherein said at least one liner comprises a first polymer coating layer formed by extrusion coating of a furandicarboxylic acid (FDCA) based resin onto at least one surface of the liner characterized in that the FDCA based resin comprises at least 50 % by weight of a FDCA based polymer.

2. The corrugated board according to claim 1 , wherein said FDCA based resin comprises at least 70 % by weight, preferably at least 90 % by weight, of said FDCA based polymer.

3. The corrugated board according to any of the preceding claims wherein the FDCA based polymer has a melting temperature (Tm) above 170 °C, preferably above 190 °C.

4. The corrugated board according to any of the preceding claims wherein the FDCA based polymer has an intrinsic viscosity of less than 0.9 dl / g, preferably between 0.5-0.9 dl / g, as determined according to ISO 1628.

5. The corrugated board according to any of the preceding claims wherein the FDCA based polymer has a crystallinity between 5-40%, preferably between 10-35% and even more preferred between 15-25%, measured according to ASTM E794-06 (2018)6. The corrugated board according to any one of the preceding claims, wherein the liner further comprises at least one second polymer coating layer disposed on top of the first coating layer.

7. The corrugated board according to claim 6, wherein the at least one second polymer coating layer comprises a FDCA based polymer, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP) and / or polylactic acid (PLA).

8. The corrugated board according to any one of the preceding claims, wherein the first and / or second coating layer / s are applied to the liner at a grammage ofless than 50 gsm, preferably less than 40 gsm, more preferably less than 35 gsm, measured according to ISO 536.

9. The corrugated board according to any of the preceding claims wherein theFDCA based polymer is polyethylene furanoate (PEF), polybutylene furanoate (PBF), polytrimethylene furandicarboxylate (PTF), polypentamehylene furanoate (PPeF), polyheamethylene furanoate (PHF) or polypropylene furanotate (PPF).

10. The corrugated board according to any of the preceding claims wherein the corrugated board has a grammage between 60-500 gsm, measured according to ISO 536.11 . The corrugated board according to any of the preceding claims wherein the liner and / or corrugated medium has a grammage between 20-250 gsm, preferably between 80-200 gsm, measured according to ISO 536.

12. The corrugated board according to any of the preceding claims wherein the coated side of the corrugated board has less than 5 pinholes / m2, as determined according to EN13676:2001 .

13. A method for manufacturing a corrugated board, wherein said method comprises the steps of: a) providing a containerboard substrate, b) subjecting the containerboard substrate through a corrugator to form a corrugated medium, c) providing at least one liner, d) providing a FDCA based resin, e) applying the FDCA based resin onto the at least one liner by extrusion coating to form a first coating layer, f) applying an adhesive to at least one surface of the corrugated medium g) attaching said corrugated medium to said liner in such way that the adhesive is located between the corrugated medium and the liner to form the corrugated board,characterized in that the FDCA based resin comprises at least 50 % by weight of a FDCA based polymer.

14. The method according to claim 13 wherein the method comprises the step of preheating the liner to a temperature of at least 100°C, before attaching the corrugated medium to the liner.

15. The method according to any of the claims 13-14 wherein the method comprises the step of cooling the first coating layer after extrusion coating in a chill roll at a temperature of between 5-60 °C for a time of at least 0.15 s, preferably between 0.15-10 seconds.

16. The method according to any of the claims 13-15 wherein the temperature in the corrugator is above 125°C.

17. The method according to any of the claims 13-16 wherein the method comprises the step of drying the liner to a moisture content of between 5-14 % by weight before application of the FDCA based coating, preferably between 8- 11 t% by weight, measure according to ISO 287.