A method for producing a fiber based article

Abstract

There is provided a method for producing a moulded fiber based article. There is also provided a moulded fiber based article.

Description

TECHNICAL FIELD The present disclosure generally relates to a method for producing a fiber based article. The disclosure relates particularly, though not exclusively, to a method for producing a fiber based article by moulding a fiber stock. BACKGROUND This section illustrates useful background information without admission of any technique described herein representative of the state of the art. Pollution caused by single use plastic containers and packaging materials is epidemic, scarring the global landscape and threatening delicate ecosystems and the life forms that inhabit them. Single use containers migrate along waterways to the oceans in the form of Styrofoam and expanded polystyrene (EPS) packaging, to-go containers, bottles, thin film bags and photo-degraded plastic pellets. Sustainable solutions for reducing plastic pollution are gaining momentum. However, continuing adoption requires that these solutions not only be good for the environment, but also competitive with plastics from both a performance and a cost standpoint. By way of brief background, molded paper pulp (molded fiber) has been used since the 1930’s to make containers, trays and other packages, but experienced a decline in the 1970s after the introduction of fossil based plastic foam packaging. Paper pulp can be produced from old newsprint, corrugated boxes and other plant fibers. Today, molded pulp packaging is widely used for electronics, household goods, automotive parts and medical products, and as an edge / corner protector or pallet tray for shipping electronic and other fragile components. Cellulose fiber-based packaging products are biodegradable, compostable and, unlike fossil based plastics, do not migrate into the ocean. However, presently known fiber technologies are not well suited for use with meat and poultry, prepared food, produce, microwavable food, or as lids for beverage containers such as hot coffee. In particular, selectively integrating one or more oil, water, vapor, and / or oxygen barriers into the slurry, and / or selectively applying one or more of the barrier layers to all or a portion of the surface of the finished packaging product, can be cumbersome, time consuming, and expensive. Depending on molded pulp application, oil, grease, water, water vapor, oxygen and / or other gas or liquid barrier properties are needed in different container types. Use of suitable slurry chemicals can improve process efficiency, mechanical properties, barrier properties and / or surface coatability and therefore, make production of molded pulp products more competitive against products made from planar board. SUMMARY In a first aspect the present invention provides a method for producing a moulded fiber based article, the method comprising providing a fibre stock comprising cellulosic fibers; introducing to the fiber stock resin and alkyl ketene dimer (AKD); and moulding the fiber stock. In a second aspect the present invention provides a moulded fiber based article, wherein the moulded fiber based article comprises resin and AKD, and optionally aluminum ions, or wherein the moulded fiber based article is produced with the method according to the present invention. In a third aspect the present invention provides a use of resin and AKD, and in addition optionally aluminum ions for improving hydrophobity of a moulded fiber based article. It has now been surprisingly found that moulded, such as thermoformed, fiber based articles comprising resin, such as rosin, and AKD, and in addition optionally aluminum ions provide improved hydrophobity for a moulded fiber based article. It was also surprisingly found that resin, such as rosin, and AKD together provide better sizing in terms of lower Cobb values than AKD or rosin alone provides. The lower the Cobb value is the better is water resistance, i.e. hydrophobicity. The fiber based articles of the present invention are at least partly biodegradable and compostable, preferably mostly biodegradable and compostable, more preferably almost totally biodegradable and compostable, most preferably biodegradable and compostable. The appended claims define the scope of protection. BRIEF DESCRIPTION OF FIGURES Figure 1 shows Cobb 5 minutes values with alkyl ketene dimer (AKD) + cationic polyacryl amide (CPAM); aluminium sulfate (Alum) + polyaluminium chloride (PAC) rosin blend + CPAM; Alum + AKD + rosin (20+80%) blend + CPAM. Figure 2 shows Cobb 30 minutes values with Alum + Alum rosin blend + cationic starch; Alum + AKD+rosin (20-80%) blend + cationic starch; AKD + cationic starch; AKD + Alum + Alum rosin + cationic starch; AKD + Alum + PAC rosin + cationic starch. Figure 3 shows Black coffee raw edge penetration with Alum + Alum rosin + cationi starch; Alum + PAC rosin + cationic starch; Alum + AKD rosin (20-80%) blend + cationic starch. Figure 4 shows Cobb 15 minutes values with Alum + Alum rosin + anionic polyacryl amide (APAM) at pH 5.2; Alum + PAC rosin + APAM at pH 7.0; AKD + APAM at 7.0; Alum + AKD rosin blend (20-80%) + APAM at pH 5.2. Figure 5 shows high moisture tensile index with Alum + Alum rosin + APAM at pH 5.2; Alum + PAC rosin + APAM at pH 7.0; AKD + APAM at pH 7.0; Alum + AKD rosin blend (20-80%) + APAM at pH 5.2; APAM. Figure 6 shows Cobb15 minutes with Alum + AKD rosin blend (86-14%) at pH 5.2; PAC + AKD rosin blend (86-14%) at pH 7.0; Alum + AKD rosin blend (20-80%) + APAM at pH 7.0; Alum + AKD rosin blend (20-80%) + APAM at pH 5.2. DETAILED DESCRIPTION In a first aspect the present invention provides a method for producing a moulded fiber based article, the method comprising providing a fibre stock comprising cellulosic fibers; introducing to the fiber stock resin and alkyl ketene dimer (AKD); and moulding the fiber stock. In one embodiment the resin comprises rosin, chemically modified rosin, physically modified rosin or a mixture thereof, preferably chemically modified rosin. In one embodiment the resin comprises rosin, fortified rosin, rosin ester, fortified rosin ester, styrene rosin, alpha methyl styrene rosin or a mixture thereof, preferably rosin. In one embodiment the method additionally comprises introducing aluminum ions to the fiber stock. In one embodiment the aluminum ions comprise aluminum sulphate (ALS), polyaluminium chloride (PAC) or a mixture hereof. In one embodiment aluminum sulphate is introduced to the fiber stock when pH of the fiber stock is less than 6.5, preferably less than 5.5. In one embodiment polyaluminium chloride is introduced to the fiber stock when pH of the fiber stock is more than 6.5. In one embodiment the amount of the introduced aluminum ions is from 1.0 to 1.5 times more than amount of resin introduced to the fiber stock, based on dry weights. In one embodiment the total amount of the resin and AKD is 0.1-40 kg / ton of dry fiber stock, preferably 2-10 kg / ton of dry fiber stock, more preferably 4-8 kg / ton of dry fiber stock. In one embodiment weight ratio of the resin to the AKD is from 6:1 to 1:6, based on dry weights. In one embodiment the resin, AKD and optionally aluminum ions are introduced as a blend to the fiber stock. In one embodiment the resin, AKD and optionally aluminum ions are introduced simultaneously but separately to the fiber stock. In one embodiment the resin, AKD and optionally aluminum ions are introduced sequentially to the fiber stock. In one embodiment the resin and AKD are introduced to the fiber stock prior introducing the aluminum ions to the fiber stock. In one embodiment the aluminum ions are introduced to the fiber stock prior introducing the resin and AKD to the fiber stock. In one embodiment the aluminum ions are introduced to the fiber stock in between introducing resin and AKD to the fiber stock. In one embodiment pigment material is introduced to the fiber stock. In one embodiment the pigment material is introduced to the fiber stock at the same time as the resin, AKD and optionally aluminum ions. In one embodiment the pigment material, the resin, AKD and optionally aluminum ions as a blend to the fiber stock. In one embodiment the pigment material, the resin, AKD and optionally aluminum ions are introduced sequentially to the fiber stock. In one embodiment the pigment material comprises talc, kaolin clay, calcium carbonate, titanium dioxide or a mixture thereof. In one embodiment, sizing agent, fixative, retention aid, drainage aid, wet strength agent, dry strength agent, barrier agent or a blend thereof is introduced to the fiber stock, preferably before introducing the resin, AKD and optionally aluminum ions to the fiber stock. In one embodiment the sizing agent comprises alkenyl succinic anhydride (ASA), xx or a mixture thereof. In one embodiment the retention aid comprises cationic polyacryl amide (CPAM), cationic starch, polyamidoamine-epichlorohydrin (PAE), polyvinyl alcohol (PVA), polyvinylamine (PVAm), poly ethylenimine (PEI) or a mixture thereof. In one embodiment ASA, rosin or a mixture thereof is introduced in an amount of 0.1 - 4%, preferably 0.5-1.5% based on dry weight of the fiber stock. In one embodiment the sizing agent, fixative, drainage aid or a mixture thereof comprises aluminium sulphate (ALS), polyaluminium chloride (PAC), poly(diallyldimethylammonium chloride) (PDACMAC), cationic polyacrylamide (CPAM), polyethylenimine (PEI), polyamine (PA), polyvinylalcohol (PVA), polyvinylamine (PVAm), silica sol or a mixture thereof. In one embodiment the dry strength agent comprises cationic starch, polyamidoamineepichlorohydrin (PAE), polyamine, polyvinyl alcohol (PVA) or a mixture thereof. The barrier agent are agents that provide oil, grease, water, vapor, oxygen and / or other gas or liquid barrier properties for the moulded fiber based article. Examples of such agents are per- and polyfluoroalkyl and silicon substances for water, oil and grease barrier and styrene butadiene, ethyl vinyl acetate, ethyl vinyl alcohol and / or polyvinyl acetate for the other barriers respectively. In one embodiment pH of the fiber stock comprising cellulosic fibers is 4-5.5 when the resin is introduced to the fiber stock. In one embodiment pH of the fiber stock comprising cellulosic fibers is 4-8 when a blend comprising the resin and AKD is introduced to the fiber stock. In one embodiment consistency of the fiber stock comprising cellulosic fibers is 0.1 %-10 %, preferably 0.1 %-5 %, more preferably 0.2 %-1.0 %. The moulding, i.e. moulding step or moulding process, can be any suitable method known in the art. In one embodiment the moulding comprises wet forming, wet moulding, vacuum forming, vacuum forming coating, vacuum moulding, extrusion forming, extrusion moulding, compression molding, thermoforming, dry forming, dry moulding, hot pressing, hot press drying, hot moulding, heat pressing, heat moulding, thermomoulding, air forming, foam forming or a combination thereof. In one embodiment the moulding is thermoforming, preferably heat pressing, hot pressing, hot press drying, thermomoulding, compression moulding or a combination thereof. In one embodiment the moulding is a combination of vacuum forming, wet moulding and moulding using both heat and mechanical pressure, such as thermoforming, compression moulding, hot press drying or thermoforming drying. In one embodiment the fiber stock is moulded to a sheet. In one embodiment the fiber stock is formed to a sheet, preferably thermoformed to a sheet. In the context of the present application by term “sheet” is meant an article having smaller thickness than length and width. In the context of the present application by term “two-dimensional, 2D, article” is meant a 2D-article originally been made to planar shape and has a smaller thickness than length and width. The 2D-article can be folded or bended to a three-dimensional, 3D, article. In the context of the present application by term “three-dimensional, 3D, article” is meant an article having three dimensions. In the context of the present application a sheet is not considered to be a three-dimensional, 3D, article. In one embodiment the sheet is formed to a three-dimensional, 3D, article. In one embodiment the fiber stock is moulded to a three-dimensional, 3D, article. In one embodiment the fiber stock with or without foam is vacuum formed, extrusion formed, injection formed, blow formed, wet pressed and / or drained by help of vacuum, unrestrained and / or restrained dried, compacted in one or more directions, polymer impregnated, polymer laminated, polymer coated or a combination thereof, to a two-dimensional, 2D, sheet having thickness of 0.1 mm -10 mm, preferably 0.3 mm - 2 mm. In one embodiment the 2D sheet is further thermoformed (i.e. dry moulded, i.e. dry formed) to a threedimensional, 3D, article having preferably length and width of 5 cm - 50 cm, depth of 2 cm -20 cm and wall thickness of 0.1 mm - 2 mm. In one embodiment the fiber stock is wet moulded and the wet moulded fiber stock is moulded to a three-dimensional, 3D, article. In one embodiment temperature of mould(s) in heat pressing, hot pressing, hot press drying, heat compression, hot compression, thermoforming or thermomoulding is 100 °C - 400 °C, preferably 130 °C-220 °C. In one embodiment mechanical pressure applied on fiber stock or two- or three-dimensional fiber based article in heat pressing, hot pressing, hot press drying, heat compression, hot compression, thermoforming or thermomoulding is 0.1 bar - 1000 bar, preferably 1-250 bar and pressure can alternate during heat pressing, hot pressing, hot press drying, heat compression, hot compression, thermoforming or thermomoulding depending on manufacturing technology, equipment and moulded fiber product application. In one embodiment the moulding is thermoforming, heat pressing, thermomoulding, hot pressing, hot press drying, heat compression moulding, hot compression moulding, wet or dry moulding and / or wet or dry forming to form densifying or a combination thereof, to a three dimensional article. In one embodiment the fiber stock comprising the resin and AKD is vacuum forming coated on a vacuum forming coated fiber stock that is substantially free, preferably free of resin and AKD, followed by moulding the fiber stocks. In one embodiment the fiber stock comprising the resin and AKD is vacuum forming coated on 2-10 vacuum forming coated fiber stocks stock that are substantially free, preferably free of the resin and AKD followed by moulding the fiber stocks. In one embodiment the fiber stock comprising cellulosic fibers comprises natural fibers, synthetic fibers or a mixture thereof. Preferably the fibers are plant origin comprising recycled, chemical and / or mechanical hardwood and softwood pulps, sugar cane (such as bagasse), bamboo, marley, wheat, maize, corn, oats, barley, rice, rye, tomato, sorghum, rape seed, palm oil plants, flax, hemp, ramie, cotton, kenaf, jute, banana, cannabis, peat, moss or a mixture thereof. In a second aspect the present invention provides a moulded fiber based article, wherein the moulded fiber based article comprises resin and AKD, and optionally aluminum ions, or wherein the moulded fiber based article is produced with the method according to the present invention. In one embodiment the moulded fiber based article comprises aluminum ions. In one embodiment total amount of the resin and AKD in the moulded fiber based article is 0.05 wt.%-8 wt.%, preferably 0.1 wt.%-6 wt.%, more preferably 1 wt.%-4 wt.%, based on the dry weight of the moulded fiber based article. In one embodiment weight ratio of the resin to the AKD is from 6:1 to 1:6, based on dry weights. In one embodiment amount of aluminum ions is from 1.0 to 1.5 times more than amount of resin in the moulded fiber based article, based on dry weight of the moulded fiber based article. In one embodiment the moulded fiber based article comprises pigment material. In one embodiment the moulded fiber based article is thermoformed fiber based article, preferably hot pressed, hot pressed dried, heat pressed, heat compression moulded, hot compression moulded fiber based article or thermomoulded fiber based article. In one embodiment amount of the fiber in the moulded fiber based article is 50 wt.%-99 wt.%, preferably 80 wt.%-97 wt.%, more preferably 90 wt.%-97 wt.%, based on dry weight of the moulded fiber based article. In one embodiment amount of the pigment material in the moulded fiber based article is 0.01 wt.%-10 wt.%, preferably 0.5 wt.%-5 wt.%, based on dry weight of the moulded fiber based article. In one embodiment the moulded fiber based article comprises a sizing agent, fixative, retention aid, drainage aid, wet strength agent, dry strength agent, barrier agent or a mixture thereof. In one embodiment amount of the sizing agent fixative, retention aid, drainage aid, wet strength agent, dry strength agent, barrier agent or a mixture thereof in the moulded fiber based article is 0.01 wt.%-5 wt.%, preferably 0.1 wt.%-2.0 wt.%, based on dry weight of the moulded fiber based article. In one embodiment the moulded fiber based article comprises food packages, food service items, drink packages, goods packages, preferably oven proof trays, microwave safe trays, clamshell boxes, other food boxes, cups, trays, plates, bottles or cup lids. In one embodiment the moulded fiber based article is produced with the method according to the present invention. In a third aspect the present invention provides use of resin and AKD, and optionally aluminum ions for improving hydrophobity of a moulded fiber based article. In one embodiment the aluminum ions are used in addition to the resin and AKD for improving hydrophobity of a moulded fiber based article In one embodiment pigment material is used in addition to the resin and AKD and optional aluminum ions for improving hydrophobity of a moulded fiber based article. In one embodiment fixative, retention aid, drainage aid, wet strength agent, dry strength agent or a mixture thereof is used in addition to the resin and AKD, optional aluminum ions and optional pigment material for improving hydrophobity of a moulded fiber based article. EXAMPLES In Figures 1 to 3 furnish properties were as follows: pulp was SR 25 NBHWK+NBSWK (70+30%), pH was 5-5.2 with rosin and AKD+rosin blend and 7-7.5 with AKD and AKD+rosin separately added. 150 mg of NaHCOs / kg fiber stock was added only with AKD. Conductivity was 0.5 mS / cm (50-100ppm Ca). 6 kg of dry cationic starch / t dry was added as last chemical to fiber stock for retention and strength. Alum was dosed to stock only if rosin was added too. The alum dosage was as dry powder to rosin ratio = 1.5. In Figures 4-6 furnish properties were the same as in Figures 1 to 3 except instead of cationic starch 12 kg of anionic poly acrylamide 11 (dry on dry) was added to fiber stock as last chemical for retention, charge control / dispersion and strength chemical. Another difference to Figures 1 -3 was that alum dosage was as dry powder to rosin ratio = 1.0-1.25 and PAC as 9.2% Al product was added with similar ratio to rosin as ALS. Example 1, according to the present invention The chemicals as shown in Figures 1-6 are introduced to the fiber stock in the order as shown in Figures 1-6. After each introduction of a chemical to the fiber stock the fiber stock is mixed for 1,5 minutes. Preparation of two-dimensional, 2D, article / sheet according to the present invention 2D molded sheets were prepared with Rapid Kothen former and hot press dried at 150200°C between steel plates under vacuum suction and mechanical pressure. Dryness’ of the sheets after vacuum drainage, wet press and hot press were -20-25%, -27-33% and -93-99% respectively. Grammage of the RK sheets was 200-800 g / m2 and density was 0.50.7 g / cm3. Preparation of three-dimensional, 3D, article according to the present invention After introducing the chemicals to the fiber stock according to the Example 1 a 3D shaped forming wire with suction mould is dipped into the fiber stock and fiber stock material is drawn / formed against the 3D wire with 200 - 500 micron openings under up to 900 mBar vacuum. Formed 3D article is lifted up from the fiber stock and vacuum suction assisted drainage with very short and light wet press is continued until dryness of wet moulded 3D article is 33 % on average. Wet moulded 3D article is then transferred on to heated counter mould (130-200 °C) and hot press dried and thermoformed to 0.2 - 1.2 mm thickness and final dryness of 90 - 96%. The 3D article may be hot press dried and thermoformed to a wall thickness of 0.2 mm-1.2 mm, such as 0.5 mm- 0.8 mm, length of 5 cm-50 cm, width of 5 cm-50 cm and depth of 2 cm-20 cm. Cobb test Cobb test was performed using the test method based on standard ISO 535. Results shown in Table 1 and 2 show that with AKD-rosin blend or AKD+rosin separate addition to the fiber stock lower Cobb 5min and Cobb 30min values i.e. higher hydrophobicity level can be 5 achieved than what is possible with 4 kg AKD wax / t dry pulp dosage which is the maximum AKD wax dosage that is allowed by the most restricted food contact regulations. Black coffee raw edge penetration test Black coffee raw edge penetration test was performed using the test method based on standard ISO 187:1990 and ISO 534:2005. Results shown in Table 1 show that with AKD-10 rosin blend lower REP values i.e. lower plane directional hydrophobicity level can be achieved than with 4 kg AKD wax 11 dry pulp which is the maximum AKD wax dosage that is allowed by the most restricted food contact regulations. Table 1. Results of the Cobb 30min and black coffee raw edge penetration test. Chemicals Dosage Cobb 30min 80 °C black coffee REP [kg dry alum, AKD, rosin or AKD-rosin blend / 1 dry pulp] [g / m2] [kg / m2] Alum + alum rosin + cationic starch 6+4 100,2 2,20 12+8 84,4 1,83 24+16 78,2 1,34 Alum + PAC rosin + cationic starch 6+4 2,04 12+8 1,30 24+16 1,09 Alum + AKD-rosin (20-80%) blend + cationic starch 6+5 88,4 0,91 12+10 84,3 1,22 24+20 79,6 1,21 AKD + alum + alum rosin + cationic starch 4+1+0,67 89,4 1,21 4+24+16 76,1 1,57 AKD + alum + PAC rosin + cationic starch 4+1+0,67 84,8 1,31 4+24+16 83,5 1,17 AKD + cationic starch 4 86,1 0,98 8 80,9 1,08 15 Table 2. Results of the Cobb 5min tests. Chemistry Dosage Cobb5min [kg AKD, rosin or AKD-rosin blend / tdry] [g / m2] S.D. AKD + CPAM 1+0,15 45,8 2,7 2+0,15 40,0 0,0 4+0,15 36,0 0,5 Alum + PAC rosin + CPAM 2+0,15 53,4 3,0 4+0,15 40,1 0,2 8+0,15 37,2 0,7 4+0,15 41,4 1,7 6+0,15 37,8 0,5 12+0,15 38,0 0,5 Alum + AKD+rosin (20+80%) blend + CPAM 2+0,15 40,4 1,6 4+0,15 37,5 0,5 8+0,15 34,8 0,4 High moisture tensile index test High moisture tensile index test was performed using the test method based on standard 5 ISO 1924-3:2005. Results shown in Figure 3 show that with AKD-rosin blend lower Cobb 15min level i.e. more hydrophobicity and higher high moisture tensile index can be achieved than with rosin or 4 kg AKD wax 11 dry pulp which is the maximum AKD wax dosage that is allowed by the most restricted food contact regulations. Table 3. Results of Cobb 15min and high moisture tensile tests. Chemistry Dosage [kg AKD, rosin or AKD-rosin blend and APAM / tdry pulp Cobb 15min High moisture (RH90 / 30C) tensile index [g / m2] S.D. [Nm / g S.D. 95% Cl Only APAM 12 788,6 23,9 21,6 1,6 1,2 pH 5,2: alum + alum rosin + APAM 8+12 68,6 3,7 23,1 3,3 2,6 12+12 61,6 2,4 32,2 3,2 2,4 pH 7,0: alum + PAC rosin + APAM 8+12 31,4 4,7 3,6 12+12 58,2 0,3 34,4 4,8 3,7 pH 5,2: alum + AKD-rosin blend (20-80%) + APAM 5+12 63,4 0,7 30,7 4,5 3,5 10+12 56,8 0,6 35,7 5,7 4,4 15+12 54,7 42,6 6,7 5,1 pH 7,0: AKD + APAM 4+12 63,8 0,4 23,1 2,5 1,9 8+12 63,9 2,4 28,1 2,4 1,8 The foregoing description has provided by way of non-limiting examples of particular implementations and embodiments a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodiments 5 presented in the foregoing, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention. Furthermore, some of the features of the afore-disclosed example embodiments may be used to advantage without the corresponding use of other features. As such, the foregoing 10 description shall be considered as merely illustrative of the principles of the present invention, and not in limitation thereof. Hence, the scope of the invention is only restricted by the appended patent claims.

Claims

1. A method for producing a moulded fiber based article, the method comprising providing a fibre stock comprising cellulosic fibers;introducing to the fiber stock resin and alkyl ketene dimer (AKD); and moulding the fiber stock.

2. The method according to claim 1, wherein the resin comprises rosin, chemically modified rosin, physically modified rosin ora mixture thereof, preferably chemically modified rosin.

3. The method according to claim 1 or 2, wherein total amount of the resin and AKD is 0.1-40 kg / ton of dry fiber stock, preferably 2-10 kg / ton of dry fiber stock, more preferably 48 kg / ton of dry fiber stock.

4. The method according to any of claims 1-3, wherein weight ratio of the resin to the AKD is from 6:1 to 1:6, based on dry weights.

5. The method according to any of claims 1-4, wherein additionally aluminum ions are introduced to the fiber stock.

6. The method according to claim 5, wherein the aluminum ions comprise aluminum sulphate, polyaluminium chloride or a mixture thereof.

7. The method according to claim 5 or 6, wherein amount of the introduced aluminum ions is from 1.0 to 1.5 times more than amount of resin introduced to the fiber stock, based on dry weights.

8. The method according to any of claims 1-7, wherein the resin, AKD and optionally aluminum ions are introduced as a mixture to the fiber stock.

9. The method according to any of claims 1-8, wherein the resin, AKD and optionally aluminum ions are introduced simultaneously but separately to the fiber stock.

10. The method according to any of claims 1-9, wherein the resin, AKD and optionally aluminum ions are introduced sequentially to the fiber stock.

11. The method according to any of claims 1-10, wherein the fiber stock is formed to a sheet.

12. The method according to claim 11, wherein the sheet is formed to a threedimensional, 3D, article.

13. The method according to any of claims 1 -12, wherein the fiber stock is moulded to a three-dimensional, 3D, article.

14. The method according to any of claims 1-13, wherein the fiber stock is wet moulded and the wet moulded fiber stock is moulded to a three-dimensional, 3D, article15. The method according to any of claims 1-14, wherein the moulding comprises wet forming, wet moulding, vacuum forming, vacuum forming coating, vacuum moulding, extrusion forming, extrusion moulding, compression molding, thermoforming, dry forming, dry moulding, hot pressing, hot press drying, hot moulding, heat pressing, heat moulding, thermomoulding, air forming, foam forming or a combination thereof.

16. The method according to any one of claims 1-14, wherein pigment material is introduced to the fiber stock.

17. The method according to any of claims 1-15, wherein fixative, retention aid, drainage aid, wet strength agent, dry strength agent, barrier agent or a mixture thereof is introduced to the fiber stock.

18. A moulded fiber based article, wherein the moulded fiber based article comprises resin and AKD, and optionally aluminum ions, orwherein the moulded fiber based article is produced with the method according to any of claims 1-17.

19. The moulded fiber based article according to claim 18, wherein the moulded fiber based article comprises food packages, food service items, drink packages, goods packages, preferably oven proof trays, microwave safe trays, clamshell boxes, other food boxes, cups, trays, plates, bottles or cup lids.

20. Use of resin and AKD, and in additionoptionally aluminum ions for improving hydrophobity of a moulded fiber based article.

Images