Method for producing a packaging material

Abstract

The invention relates to a method for producing a packaging material comprising providing a sheet of paper, board, or the like (1), providing an aqueous solution comprising alpha-1,3-glucan or a substituted derivative thereof (2), adjusting the pH of the aqueous solution comprising alpha-1,3-glucan or a substituted derivative thereof to obtain a pH adjusted aqueous solution comprising alpha-1,3-glucan or a substituted derivative thereof (3) and coating the sheet of paper, board, or the like with the pH adjusted aqueous solution comprising alpha-1,3-glucan or a substituted derivative thereof (4). The present invention also relates to a packaging material comprising paper, board, or the like and alpha-1,3-glucan or a substituted derivative thereof and to the use of alpha-1,3-glucan or a substituted derivative thereof as an oxygen barrier on a paper, board, or the like.

Description

[0001] METHOD FOR PRODUCING A PACKAGING MATERIAL

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a method for producing a packaging material comprising providing a sheet of paper, board, or the like and coating it with a pH adj usted aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof . The present invention also relates to a packaging material comprising paper, board, or the like and alpha- 1 , 3-glucan or a substituted derivative thereof and to the use of alpha- 1 , 3-glucan or a substituted derivative thereof as an oxygen barrier on a paper, board, or the like .

[0004] BACKGROUND OF THE INVENTION

[0005] Packaging materials are used for surrounding, protecting, storing, and transporting products . They serve multiple purposes , including ensuring product safety, preserving quality, and facilitating ease of handling .

[0006] For many years , plastics such as polyethylene , polypropylene , and polyethylene terephthalate have been widely used in packaging due to their desirable properties . These materials are ef fective barriers against water, vapor, oil , grease , and oxygen, making them particularly suitable for packaging food, beverages , pharmaceuticals , cosmetics , and personal care products .

[0007] However, these plastics are not biodegradable , may result in microplastic pollution and their manufacturing releases a large amount of greenhouse gases .

[0008] While work has begun to address this issue ( e . g . , WO2017074859, W02018200437 , WO2023137258 ) , there remains an urgent need for further development of packaging materials that retain these essential properties while being environmentally sustainable .

[0009] Board and paper are more environmentally friendly options to plastics and show potential as packaging material . However, these do not inherently have water, vapor, oil , grease , and / or oxygen barrier properties .

[0010] As such, solutions for modi fying board, paper, or the like to obtain barriers against water, vapor, oil , grease , and / or oxygen is needed .

[0011] SUMMARY

[0012] According to a first aspect , a method for producing a packaging material is provided, the method comprising, i . providing a sheet of paper, board, or the like ; ii . optionally coating the sheet of paper, board, or the like with a water-vapor and / or oil-grease barrier to form a third layer on the sheet of paper, board, or the like ; iii . providing an aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof ; iv . adj usting the pH of the aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof to obtain a pH adj usted aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof ; and v . coating the sheet of paper, board, or the like or the third layer with the pH adj usted aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof to form a f irst layer on the sheet of paper, board, or the like or on the third layer .

[0013] According to a second aspect , a packaging material comprising paper, board, or the like and a first layer, the first layer comprising alpha- 1 , 3-glucan or a substituted derivative thereof is provided .

[0014] According to a third aspect, use of alpha- 1 , 3- glucan or a substituted derivative thereof as an oxygen barrier on a paper, board, or the like is provided .

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings , which are included to provide a further understanding of the invention and constitute a part of this speci fication, illustrate embodiments of the invention and together with the description help to explain the principles of the invention . In the drawings :

[0017] Figure 1 shows a method for producing a packaging material comprising coating a paper, board or the like with alpha- 1 , 3-glucan or a substituted derivative thereof ;

[0018] Figure 2 shows a method for producing a packaging material comprising coating a paper, board or the like with alpha- 1 , 3-glucan or a substituted derivative thereof and a water-vapor and / or oil-grease barrier ; and

[0019] Figure 3 shows a method for producing a packaging material comprising coating a paper, board or the like with alpha- 1 , 3-glucan or a substituted derivative thereof and at least two layers of water-vapor and / or oil-grease barrier . DETAILED DESCRIPTION

[0020] It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways . The invention and its embodiments are thus not limited to the examples described below, instead they may vary within the scope of the claims .

[0021] The description below related to the first aspect apply also to the second and third aspects and vice versa . The description below related to the second aspect apply also to the third aspect and vice versa .

[0022] A method for producing a packaging material

[0023] According to a first aspect , a method for producing a packaging material is provided, the method comprising, i . providing a sheet of paper, board, or the like ( 1 ) ; ii . optionally coating the sheet of paper, board, or the like with a water-vapor and / or oil-grease barrier to form a third layer on the sheet of paper, board, or the like ( 6 ) ; iii . providing an aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof ( 2 ) ; iv . adj usting the pH of the aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof to obtain a pH adj usted aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof ( 3 ) ; and v. coating the sheet of paper, board, or the like or the third layer with the pH adjusted aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof to form a first layer on the sheet of paper, board, or the like or on the third layer (4) .

[0024] A packaging material may refer to any material used to surround, protect, store or transport products during operating, storage and distribution. It may serve multiple purposes, such as ensuring the safety of the product, preserving its quality and facilitating ease of handling.

[0025] Paper may refer to a thin, flexible material made from cellulose fibers derived from wood, recycled materials, or plants. It is typically produced by pressing wet fibers into sheets and drying the sheets. The paper may be measured by thickness or grammage, which may be in the range of 40 to 400 g / m2, or 50 to 350 g / m2, or 50 to 300 g / m2, or 60 to 250 g / m2, or 70 to 200 g / m2, or 80 to 150 g / m2, or 90 to 100 g / m2.

[0026] Board may refer to a thick, rigid material made from cellulose fibers, recycled materials, or plants, often created by compressing multiple layers of fiber pulp. It may be tougher than paper and may be used in applications that require durability. Cardboard, chipboard and corrugated board are examples of board. The board may be measured by thickness or grammage, which may be in the range of 250 to 800 g / m2, or 260 to 750 g / m2, or 270 to 700 g / m2, or 280 to 650 g / m2, or 290 to 600 g / m2, or 300 to 550 g / m2, or 310 to 500 g / m2.

[0027] "Or the like" may refer to "things of a similar kind" or "others like it". Coating may refer to the application of a thin layer of a substance onto the surface of paper or board .

[0028] A water-vapor and / or oil-grease barrier may refer to a layer applied to the paper, board, or the like , which layer may prevent the passage of water, vapor , oil , and / or grease through the surface . The water-vapor and / or oil-grease barrier may be a material , which has properties as both a water-vapor and an oilgrease barrier . Alternatively, the water-vapor and / or oil-grease barrier may have properties of only a watervapor or an oil-grease barrier . The water-vapor and / or oil-grease barrier may also comprise several materials such that a barrier having both water-vapor and oilgrease barrier is provided . The water-vapor and / or oilgrease barrier may comprise polyethylene ( PE ) , polypropylene ( PP ) , aluminum foil , glassine paper, PET ( Polyester ) , a wax, silicone , polylactic acid ( PLA) , ethylene vinyl alcohol (EVOH) , chitosan, alginic acid and / or pul- lulan .

[0029] An aqueous solution may be a solution in which water is the solvent . The aqueous solution may comprise alpha- 1 , 3-glucan or a substituted derivative thereof such that the alpha-1 , 3-glucan or a substituted derivative thereof is partially or completely dissolved therein .

[0030] For the avoidance o f doubt , the layers may be defined as numbers ( first , second, third layer ) but this does not necessarily define the order in which the layers are applied on the paper, board, or the like . E . g . , the paper, board, or the like may be coated with the third layer and then the paper, board, or the like comprising the third layer may be coated with the first layer such that the first layer is applied on the third layer or on the paper, board, or the l ike on the other side compared to the third layer . The paper, board, or the like may also be coated with the first layer such that the third layer is not present . In one embodiment , the paper, board, or the like i s coated with the third layer and then with the first layer such that the first layer in applied on the third layer .

[0031] It has surprisingly been found that alpha- 1 , 3- glucan or a substituted derivative thereof can be used as an oxygen barrier in packaging when applied on a paper, board, or the l ike according to the method described above . Without wishing to be bound by theory, it is believed that the pH adj ustment of the aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof enables the alpha- 1 , 3-glucan or a substituted derivative thereof to bond to the paper, board, or the like or to another coating layer, e . g . the water-vapor and / or oil-grease barrier . It is desirable to use alpha- 1 , 3-glucan or a substituted derivative thereof in packaging materials as alpha- 1 , 3-glucan or a substituted derivative thereof is biodegradable .

[0032] Further, it is beneficial to pair the alpha- 1 , 3-glucan or a substituted derivative thereof with a water-vapor and / or oil-grease barrier, as the combination provides an oxygen, water-vapor and / or oil-grease barrier, which results in great protection of the material to be packed in the packaging material .

[0033] The method according to the first aspect may further comprise , vi . coating the first layer with a water-vapor and / or oil-grease barrier to form a second layer on the first layer ( 5 ) .

[0034] The water-vapor and / or oil-grease barrier of the second layer may be the same or a di f ferent material than the water-vapor and / or oil-grease barrier of the third layer . The above definition of the water-vapor and / or oi l-grease barrier may apply both to the second and third layer .

[0035] It has been found that adding a water-vapor and / or oil-grease barrier on top of an alpha- 1 , 3-glucan or a substituted derivative thereof layer provides an oxygen, water-vapor and / or oil-grease barrier, which results in great protection o f the material to be packed in the packaging material . Further, the water-vapor and / or oil-grease barrier on top of an alpha- 1 , 3-glucan or a substituted derivative thereof layer may act as a heat seal .

[0036] Step iv . according to the first aspect may compri se adding a base to the aqueous solution compris ing alpha- 1 , 3-glucan or a substituted derivative thereof , preferably wherein the base is sodium hydroxide , potassium hydroxide , calcium hydroxide, ammonium hydroxide , sodium carbonate and / or calcium carbonate . The base may also be a mixture of the beforementioned .

[0037] Step iv . according to the first aspect may compri se adj usting the pH to 11 to 14 , or 12 to 14 , or 13 to 14 .

[0038] The above pH may refer to the pH of the pH adj usted aqueous solution comprising alpha- 1 , 3-glucan or a substituted derivative thereof . The pH adjusted aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof in step iv. according to the first aspect may comprise 2 to 15 wt.%, or 3 to 14 wt.%, or 4 to 12 wt.%, or 5 to 11 wt.%, or 6 to 10 wt.%, or 7 to 9 wt.%, or 8 wt.% alpha-1 , 3-glucan or a substituted derivative thereof and / or 1 to 6 wt.%, or 2 to 5 wt.%, or 3 to 4 wt.%, or 3,5 wt.% sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonium hydroxide, sodium carbonate and / or calcium carbonate.

[0039] In one embodiment, Step iv. comprises adding sodium hydroxide to the aqueous solution comprising al- pha-1 , 3-glucan or a substituted derivative thereof, optionally such that the pH is adjusted to 13 to 14.

[0040] The base may be added in a solid, liquid or gaseous form and may dissolve in the aqueous solution completely or partially.

[0041] It has been found that altering the pH of the aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof improves significantly the bonding of the alpha-1 , 3-glucan or a substituted derivative thereof to the paper, board, or the like or to the other coating layers. The above conditions have been found optimal and to provide the best bonding properties. Sodium hydroxide is particularly desirable as the base because it is commercially available and provides an optimal balance between performance and production cost of the packaging material.

[0042] The coating according to the first aspect may be spray coating, brush coating, gravure coating, reverse gravure coating, curtain coating, bar coating, metered si ze press coating, blade coating and / or slit coating .

[0043] Spray coating may involve atomi zing a liquid coating material and spraying it onto a surface using a spray noz zle . The coating material may be in the form of a liquid or suspension . It may allow for precise control of coating thickness and can be used for large , complex shapes .

[0044] In brush coating, the coating material may be applied to the surface using a brush or roller . Brush coating may provide a controlled application and i s ideal for coating small areas or complex designs .

[0045] Gravure coating may use a cylinder engraved with small cells that pick up the coating material and trans fer it to the paper, board, or the like to be coated . The engraved cylinder may be dipped into a reservoir of coating liquid, and the exces s liquid may be scraped of f using a blade before it is trans ferred to the paper, board, or the l ike . This technique may provide an even and controlled layer o f coating . In reverse gravure coating, the process may be similar to the regular gravure coating, but the paper, board, or the like may move in an opposite direction to the engraved cylinder . This may help in controlling the amount of coating trans ferred to the surface , may of fer better control over coating thickness and may be good for coating larger rolls or continuous materials .

[0046] Curtain coating may involve pouring a thin " curtain" of coating solution from a noz zle over the surface of the paper, board, or the like , which may move beneath the curtain . This may provide uni form coverage and thick coatings can be applied, even without defects or air bubbles , especially for continuous processes .

[0047] In bar coating, a f lat metal or ceramic bar may be used to spread a uni form layer of coating material acros s the paper, board, or the li ke . The thicknes s o f the coating may be determined by a gap between the bar and the paper, board, or the like . This may result in easy control of the thickness of the coating and can be used for applying thin, even coatings .

[0048] Metered si ze press coating may involve a roller or a pair of rollers that apply a coating to the surface of a paper, board, or the like as it passes between them . The amount of coating applied may be controlled by the pressure exerted by the rollers and the viscosity of the coating material . This may allow for controlled, consistent application and is particularly useful for large-scale , continuous coating of paper and board .

[0049] Blade coating may use a blade or kni fe to apply a precise amount of coating material to the surface . The coating may be applied and then scraped of f to a specific thickness by the blade , which ensures a smooth and even layer .

[0050] Slit coating may involve applying the coating material to a paper, board, or the like that is slit into narrow strips . The coating material may be applied to each strip, often by a roll or no z zle , and the strips may be coated individually . This may be ideal for applications that require narrow, precise coatings and is used in speciali zed industrial applications where regular coating methods cannot be applied .

[0051] Step v . according to the first aspect may comprise applying 1 to 5 layers of alpha- 1 , 3-glucan or a substituted derivative thereof at 1 to 30 g / m2, or 1 to 25 g / m2, or 1 to 20 g / m2, or 2 to 15 g / m2, or 5 to 10 g / m2, or 6 to 9 g / m2' or 7 to 8 g / m2to form the first layer, preferably wherein step v. comprises applying 2 layers of alpha-1 , 3-glucan or a substituted derivative thereof at 1 to 30 g / m2, or 1 to 25 g / m2, or 1 to 20 g / m2, or 2 to 15 g / m2, or 5 to 10 g / m2, or 6 to 9 g / m2, or 7 to 8 g / m2to form the first layer.

[0052] Applying 1 to 5 layers of alpha-1 , 3-glucan or a substituted derivative thereof at a certain g / m2may refer to the sum of the layers having the certain g / m2. For example, applying 2 layers of alpha-1 , 3-glucan or a substituted derivative thereof at 20 g / m2may refer to first applying one layer of alpha-1 , 3-glucan or a substituted derivative thereof resulting in an alpha-1, 3- glucan or a substituted derivative thereof layer having a gram per square meter of 10 g / m2and then applying on top of that layer an alpha-1 , 3-glucan or a substituted derivative thereof layer having a gram per square meter of 10 g / m2.

[0053] It has been found that the above amounts and number of layers provide the best balance between achieving oxygen barrier properties, performance of the packaging material and cost of production.

[0054] Step vi . according to the first aspect may comprise applying 1 layer of a water-vapor and / or oilgrease barrier at 1 to 20 g / m2, or 2 to 15 g / m2, or 3 to 10 g / m2to form the second layer.

[0055] Step ii. may comprise applying 1 layer of water-vapor and / or oil-grease barrier at 1 to 20 g / m2, or 2 to 15 g / m2, or 3 to 10 g / m2to form the third layer. For example , applying 1 layer of water-vapor and / or oil-grease barrier at 20 g / m2may refer to applying one layer of water-vapor and / or oil-grease barrier resulting in a layer having a gram per square meter of 20 g / m2.

[0056] It has been found that the above amounts and number of layers provide the best balance between achieving water-vapor and / or oil-grease barrier properties , performance of the packaging material and cost of production .

[0057] The method according to the first aspect may further comprise subj ecting the first and / or third layer to plasma treatment prior to applying the second and / or first layer thereon, preferably wherein the plasma treatment comprises providing a gas selected from helium, oxygen, nitrogen, air or argon, generating a plasma, and applying the plasma to the first and / or third layer, wherein the plasma treatment modi fies the surface energy of the first and / or third layer .

[0058] For the avoidance of doubt , the method may comprise subj ecting the third layer to plasma treatment prior to coating the third layer with the first layer and / or subj ecting the first layer to plasma treatment prior to coating the first layer with the second layer .

[0059] The plasma treatment may comprise providing helium, generating a plasma and applying the plasma to the first and / or third layer .

[0060] The plasma may be generated by applying an electrical field to the gas ( such as helium, oxygen, nitrogen, or argon) inside a vacuum chamber . This energy may excite the gas molecules , causing them to ioni ze and to form a plasma state , where electrons are separated from atoms and molecules . The material to be treated ( i . e . third or first layer ) may be exposed to this plasma . The plasma particles may interact with the surface of the material , for example by chemically altering the surface .

[0061] It has surprisingly been found that subj ecting the first and / or third layer to plasma treatment signi ficantly improves the binding of the first layer to the second layer and the third layer to the first layer . This results in a more durable packaging material .

[0062] The method according to the first aspect may further comprise coating the first layer with an aqueous solution comprising an acid prior to applying the second layer on the first layer, preferably wherein the pH is adj usted to 5 to 9 , or 6 to 8 , or 6 , 5 to 7 , 5 , or 7 on the first layer, preferably wherein the acid is citric acid, sul furic acid, hydrochloric acid, acetic acid, phosphoric acid, nitric acid and / or formic acid . The acid may also be a mixture of the above .

[0063] The coating may be performed as spray coating, brush coating, gravure coating, reverse gravure coating, curtain coating, bar coating, metered si ze press coating, blade coating and / or slit coating .

[0064] The pH on the first layer may be determined by contacting 10 ml of water with the first layer and measuring the pH of the water . The acid may be citric acid .

[0065] It has been found that coating the first layer with an acid, and speci fically citric acid, prior to applying the second layer on the f irst layer improve the binding of the first layer to the second layer . This results in a more durable packaging material . The method according to the first aspect may further comprise curing the first, second and / or third layer at 80 to 120 °C, or 85 to 115 °C, or 90 to 110 °C , or 95 to 105 °C for 5 sec to 10 min, or 10 sec to 8 min, or 15 sec, to 6 min, or 20 sec to 4 min, or 25 sec to 2 min, or 30 sec to 1 min .

[0066] Curing may refer to the process of hardening or setting a material , e . g . the coating, by applying heat , light , or a chemical reaction . As a result , the material may be changed from a liquid or semi-liquid state into a solid or more durable form .

[0067] The method may comprise performing the curing of the first , second and / or third layer prior to applying the subsequent layer thereon . Alternatively, the method may comprise performing the curing of the first , second and / or third layer once all layers have been applied on the paper, board, or the like .

[0068] It has been found that curing the coatings gives a more stable and durable packaging material .

[0069] When curing is performed and pH adj ustment is performed and plasma treatment is performed, the steps may be performed in the following order . For example , the method may comprise , in order, providing a sheet of paper, board, or the like , coating it with the third layer, curing the third layer, subj ecting the third layer to plasma treatment , coating it with the first layer, curing it , subj ecting it to plasma treatment , coating it with the aqueous solution comprising the acid, coating it with the second layer and curing it and optionally applying a heat seal on the second layer . I f one of the above steps is not performed, it may be removed from the process without changing the order in the process. For example, the following steps may be left out, coating the sheet of paper board or the like with the third layer, and / or curing the third layer, and / or subjecting the third layer to plasma treatment. For example, also the following steps may be left out, curing the first layer, and / or subjecting it to plasma treatment, and / or coating it with the aqueous solution comprising the acid. For example, also the following step may be left out, curing the second layer and / or applying the heat seal on it.

[0070] The paper, board, or the like according to the first aspect may comprise kraft paper, cardboard, paperboard and / or corrugated board.

[0071] The method according to the first aspect may further comprise applying a heat seal on the first or second layer.

[0072] The second layer may act as both a water-vapor and / or oil-grease barrier and as a heat seal. Alternatively, an additional heat seal layer may be applied on the second layer.

[0073] A heat seal in paper and board coating may refer to the process by which heat and / or pressure are applied to a coated paper or board surface for making a bond between the paper or board and the coating layers as well as between the coating layers. The first, second and / or third layers as well as the optional heat seal layer can melt or soften under heat and become tacky and bond when exposed to heat and / or pressure. The coated paper or board may pass through a heat-sealing process, where heat (e.g. between 120°C and 250°C) may be applied. This can be done through hot plates, heat-seal bars, or heated rollers, depending on the machinery and the desired sealing method. Along with heat, pressure may be applied during the sealing process. This may ensure that the coating material is evenly distributed and creates a strong bond between the paper and the other material. The pressure is typically applied using a sealing jaw or a set of rollers that compress the materials together for a specific amount of time. After the heating and applying pressure, the material may be cooled down quickly to solidify.

[0074] It is beneficial to use a heat seal as this ensures that the packaging material is durable. Further, it is particularly beneficial to use the second layer as both a water-vapor and / or oil-grease barrier and as a heat seal, as this reduces the complexity (less components are needed) of the packaging material.

[0075] The method may be performed such that the steps i. to vi . are performed in order.

[0076] The alpha-1, 3-glucan or a substituted derivative thereof according to the first aspect may have a molecular weight of 70 000 to 5 400 000 g / mol, or 100 000 to 5 000 000 g / mol or 200 000 to 4 000 000 g / mol.

[0077] The molecular weight may be measured according to size-exclusion chromatography (SEC) using the Malvern Panalytical OMNISEC system. The eluent may be a 0.3125 M CH3COOH + 0.3125 M CH3COONa solution with a flow rate of 0.5 mL / min at 35 °C. The column set may consist of three columns (a TSKgel PWXL guard column and two TSKgel GMPWXL columns) . A refractive index detector may be used for detection. Molecular weights and PDIs may be determined using conventional calibration with poly ( ethylene oxide ) / poly ( ethylene glycol) narrow molecular weight distribution standards (Polymer Standards Service) . Ethylene glycol (Img / mL) may be used as a flow marker. Results may be calculated using the OmniSEC software from Malvern. Samples may be dissolved in ultrapure Mil- liQ-water by heating in 95-100°C for 30 minutes and diluted with eluent including the flow marker.

[0078] It has been found that the above molecular weights are optimal for ensuring good processability of the solution resulting in even and high performing al- pha-1 , 3-gluxcan layers.

[0079] The alpha-1, 3-glucan or a substituted derivative thereof according to the first aspect may be represented by the structure, wherein Ri, R2 and R3 are independently H, and wherein n is at least 200.

[0080] One or more of Ri, R2 and R3 may be substituted with carboxymethyl (-CH2-COOH) , ethylene oxide or propylene oxide. The degree of substitution may be 0.01 to 0.3, or 0.02 to 0.2, or 0.03 to 0.1, or 0.05 to 0.1. n according to the first aspect may be 200 to 2000, or 400 to 1500, or 500 to 1000, or 700 to 900.

[0081] The alpha-1, 3-glucan or a substituted derivative thereof may be linear or branched. A branched polymer may refer to a polymer that has a main chain with one or more side chains (branches) connected to it. These branches can themselves have further branches , leading to a complex, tree-like structure . A linear polymer may re fer to a polymer, which consist of a s ingle continuous chain .

[0082] It has been found that alpha- 1 , 3-glucan or a substituted derivative thereof is particularly useful as an oxygen barrier in packaging materials because al- pha- 1 , 3-glucan or a substituted derivative thereof is bio-based . It has surprisingly been found that alpha- 1 , 3-glucan or a substituted derivative thereof can be applied to the paper, board, or the like as well as combined with other coating materials trough the pH adj ustments and possible plasma treatment / curing of the method disclosed herein .

[0083] A packaging material

[0084] According to a second aspect , a packaging material comprising paper, board, or the like and a first layer, the first layer comprising alpha- 1 , 3-glucan or a substituted derivative thereof is provided .

[0085] The packaging material according to the second aspect may further comprises a second layer, the second layer may comprise a water-vapor and / or oil-grease barrier .

[0086] The packaging material according to the second aspect may further comprises a third layer, the third layer may comprise a water-vapor and / or oil-grease barrier .

[0087] The packaging material according to the second aspect may further comprises a heat seal , preferably wherein the heat seal is arranged on the first or second layer .

[0088] The second layer may act as both a water-vapor and / or oi l-grease barrier and as a heat seal . Alternatively, an additional heat seal layer may be applied on the second layer .

[0089] The paper, board, or the like according to the second aspect may comprise a first side and a second side and wherein the first layer may be arranged on the first side and the second layer may be arranged on the first layer .

[0090] The paper, board, or the like according to the second aspect may comprise a first side and a second side and the third layer may be arranged on the first side , the first layer may be arranged on the third layer and the second layer may be arranged on the first layer .

[0091] This structure of the layers is particularly useful because the first layer is protected from water, vapor, oil and / or grease by the second and third layer . As such, a durable packaging material is obtained .

[0092] The second layer according to the second aspect may comprise 1 layer of water-vapor and / or oil-grease barrier at 1 to 20 g / m2, or 2 to 15 g / m2, or 3 to 10 g / m2.

[0093] The third layer according to the second aspect may comprise 1 layer of water-vapor and / or oil-grease barrier at 1 to 20 g / m2, or 2 to 15 g / m2, or 3 to 10 g / m2.

[0094] The first layer according to the second aspect may comprise 1 to 5 layers of alpha- 1 , 3-glucan or a substituted derivative thereof at 1 to 30 g / m2, or 1 to 25 g / m2, or 1 to 20 g / m2, or 2 to 15 g / m2, or 5 to 10 g / m2, or 6 to 9 g / m2' or 7 to 8 g / m2, preferably the first layer may comprise 2 layers of alpha-1 , 3-glucan or a substituted derivative thereof at 1 to 30 g / m2, or 1 to 25 g / m2, or 1 to 20 g / m2, or 2 to 15 g / m2, or 5 to 10 g / m2.

[0095] The alpha-1, 3-glucan or a substituted derivative thereof according to the second aspect may have a molecular weight of 70 000 to 5 400 000 g / mol, or 100 000 to 5 000 000 g / mol or 200 000 to 4 000 000 g / mol.

[0096] The alpha-1, 3-glucan or a substituted derivative thereof according to the second aspect may be represented by the structure,

[0097] - - : n r wherein Ri, R2 and R3 are independently H, and wherein n is at least 200.

[0098] One or more of Ri, R2 and R3 may be substituted with carboxymethyl (-CH2-COOH) , ethylene oxide or propylene oxide. The degree of substitution may be 0.01 to 0.3, or 0.02 to 0.2, or 0.03 to 0.1, or 0.05 to 0.1. n according to the second aspect may be 200 to 2000, or 400 to 1500, or 500 to 1000, or 700 to 900.

[0099] The packaging material may be for surrounding, protecting, storing and / or transporting food, beverages, pharmaceuticals, cosmetics and / or personal care products . Use of alpha-1 , 3-glucan or a substituted de- rivative thereof as an oxygen barrier

[0100] According to a third aspect, use of alpha-1, 3- glucan or a substituted derivative thereof as an oxygen barrier on a paper, board, or the like is provided.

[0101] The alpha-1, 3-glucan or a substituted derivative thereof according to the third aspect may have a molecular weight of 70 000 to 5 400 000 g / mol, or 100 000 to 5 000 000 g / mol or 200 000 to 4 000 000 g / mol.

[0102] The alpha-1, 3-glucan or a substituted derivative thereof according to the third aspect may be represented by the structure, wherein Ri, R2 and R3 are independently H, and wherein n is at least 200.

[0103] One or more of Ri, R2 and R3 may be substituted with carboxymethyl (-CH2-COOH) , ethylene oxide or propylene oxide. The degree of substitution may be 0.01 to 0.3, or 0.02 to 0.2, or 0.03 to 0.1, or 0.05 to 0.1. n according to the third aspect may be 200 to 2000, or 400 to 1500, or 500 to 1000, or 700 to 900. The paper, board, or the like according to the third aspect may be kraft paper, cardboard, paperboard and / or corrugated board .

[0104] EXAMPLES example 1 :

[0105] A paper was coated with an aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof, once, twice or three times.

[0106] The alpha-1, 3-glucan or a substituted derivative thereof layer was optionally subjected to plasma treatment .

[0107] The alpha-1, 3-glucan or a substituted derivative thereof coating was coated with 1 layer of watervapor and / or oil-grease barrier.

[0108] The paper was coated on the other side with 1 layer of water-vapor and / or oil-grease barrier. example 2 :

[0109] A paper was coated first with 1 layer of watervapor and / or oil-grease barrier then 1-3 layers of an aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof.

[0110] The alpha-1, 3-glucan or a substituted derivative thereof layer was optionally subjected to plasma treatment .

[0111] The alpha-1, 3-glucan or a substituted derivative thereof layer was then coated with 1-2 water-vapor and / or oil-grease barrier coating layers. example 3:

[0112] A paper was coated with an aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof, once, twice or three times. The alpha-1, 3-glucan or a substituted derivative thereof layer was optionally subjected to plasma treatment .

[0113] The alpha-1, 3-glucan or a substituted derivative thereof was then coated with 1-2 water-vapor and / or oil-grease barrier and heat seal coating layers. example 4 :

[0114] A paper was coated first with 1 layer of watervapor and / or oil-grease barrier then 1-3 layers with an aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof.

[0115] The alpha-1, 3-glucan or a substituted derivative thereof layer was optionally subjected to plasma treatment .

[0116] The alpha-1, 3-glucan or a substituted derivative thereof was then coated with 1-2 layers of watervapor and / or oil-grease barrier and heat seal coating layers . example 5:

[0117] A paper was coated with an aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof, once, twice or three times.

[0118] The alpha-1, 3-glucan or a substituted derivative thereof layer was optionally subjected to plasma treatment .

[0119] The alpha-1, 3-glucan or a substituted derivative thereof was then coated with 1-2 heat seal coating layers . example 6: A paper was coated first with 1 layer of watervapor and / or oil-grease barrier then 1-3 layers of an aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof. The alpha-1, 3-glucan or a substituted derivative thereof layer was optionally subjected to plasma treatment .

[0120] The alpha-1, 3-glucan or a substituted derivative thereof was then coated with 1-2 Heat seal coating layers.

Claims

CLAIMS1. A method for producing a packaging material, the method comprising, i. providing a sheet of paper, board, or the like (1) ; ii. optionally coating the sheet of paper, board, or the like with a water-vapor and / or oil-grease barrier to form a third layer on the sheet of paper, board, or the like (6) ; iii. providing an aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof (2) ; iv. adjusting the pH of the aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof to obtain a pH adjusted aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof ( 3 ) ; and v. coating the sheet of paper, board, or the like or the third layer with the pH adjusted aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof to form a first layer on the sheet of paper, board, or the like or on the third layer (4) wherein step v. comprises applying 2 layers of alpha-1 , 3-glucan or a substituted derivative thereof at 5 to 10 g / m2.

2. The method according to claim 1, wherein the method further comprises, vi . coating the first layer with a water-vapor and / or oil-grease barrier to form a second layer on the first layer ( 5 ) .

3. The method according to claim 1 or 2, wherein step iv. comprises adding a base to the aqueous solution comprising alpha-1 , 3-glucan or a substituted derivative thereof, preferably wherein the base is sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonium hydroxide, sodium carbonate and / or calcium carbonate .

4. The method according to claims 1 to 3, wherein step iv. comprises adjusting the pH to 11 to 14, or 12 to 14, or 13 to 14.

5. The method according to claims 1 to 4, wherein the pH adjusted aqueous solution comprising al- pha-1 , 3-glucan or a substituted derivative thereof in step iv. comprises 4 to 12 wt.%, or 5 to 11 wt.%, or 6 to 10 wt.%, or 7 to 9 wt.%, or 8 wt.% alpha-1 , 3-glucan or a substituted derivative thereof and / or 1 to 6 wt.%, or 2 to 5 wt.%, or 3 to 4 wt.%, or 3,5 wt.% sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonium hydroxide, sodium carbonate and / or calcium carbonate .

6. The method according to claims 1 to 5, wherein the coating is spray coating, brush coating, gravure coating, reverse gravure coating, curtain coating, bar coating, metered size press coating, blade coating and / or slit coating.

7. The method according to claims 1 to 6, wherein step v. comprises applying 2 layers of alpha-1,3-glucan or a substituted derivative thereof at 6 to 9 g / m2' or 7 to 8 g / m2to form the first layer.

8. The method according to claims 2 to 7, wherein step vi . comprises applying 1 layer of a watervapor and / or oil-grease barrier at 1 to 20 g / m2, or 2 to 15 g / m2, or 3 to 10 g / m2to form the second layer.

9. The method according to claims 1 to 8, wherein step ii. comprises applying 1 layer of watervapor and / or oil-grease barrier at 1 to 20 g / m2, or 2 to 15 g / m2, or 3 to 10 g / m2to form the third layer.

10. The method according to claims 2 to 9, wherein the method further comprises subjecting the first and / or third layer to plasma treatment prior to applying the second and / or first layer thereon, preferably wherein the plasma treatment comprises providing a gas selected from helium, oxygen, nitrogen, or argon, generating a plasma, and applying the plasma to the first and / or third layer, wherein the plasma treatment modifies the surface energy of the first and / or third layer .

11. The method according to claims 2 to 10, wherein the method further comprises coating the first layer with an aqueous solution comprising an acid prior to applying the second layer on the first layer, preferably wherein the pH is adjusted to 5 to 9, or 6 to 8, or 6,5 to 7,5, or 7 on the first layer, preferably wherein the acid is citric acid, sulfuric acid,hydrochloric acid, acetic acid, phosphoric acid, nitric acid and / or formic acid .12 . The method according to claims 1 to 11 , wherein the method further comprises curing the first , second and / or third layer at 80 to 120 °C, or 85 to 115 °C, or 90 to 110 °C, or 95 to 105 °C for 5 sec to 10 min, or 10 sec to 8 min, or 15 sec, to 6 min, or 20 sec to 4 min, or 25 sec to 2 min, or 30 sec to 1 min .13 . The method according to claims 1 to 12 , wherein the paper, board, or the like comprises kraft paper, cardboard, paperboard and / or corrugated board .14 . The method according to claims 1 to 13 , wherein the method further comprises applying a heat seal on the first or second layer .15 . The method according to claims 1 to 14 , wherein the alpha- 1 , 3-glucan or a substituted derivative thereof has a molecular weight of 70 000 to 5 400 000 g / mol , or 100 000 to 5 000 000 g / mol or 200 000 to 4 000 000 g / mol .16 . The method according to claims 1 to 15 , wherein the alpha- 1 , 3-glucan or a substituted derivative thereof is represented by the structure ,wherein Ri, R2 and R3 are independently H, and wherein n is at least 200.

17. The method according to claim 16, wherein n is 200 to 2000, or 400 to 1500, or 500 to 1000, or 700 to 900.

18. A packaging material comprising paper, board, or the like and a first layer, the first layer comprising 2 layers of alpha-1 , 3-glucan or a substituted derivative thereof at 5 to 10 g / m2.

19. The packaging material according to claim 18, wherein the packaging material further comprises a second layer, the second layer comprising a water-vapor and / or oil-grease barrier.

20. The packaging material according to claim 18 or 19, wherein the packaging material further comprises a third layer, the third layer comprising a water-vapor and / or oil-grease barrier.

21. The package material according to claim 18 to 20, wherein the packaging material further comprisesa heat seal , preferably wherein the heat seal in arranged on the first or second layer .22 . The packaging material according to claims19 to 21 , wherein the paper, board, or the like comprises a first side and a second side and wherein the first layer is arranged on the first side and the second layer is arranged on the first layer .23 . The packaging material according to claims20 to 21 , wherein the paper, board, or the like comprises a first side and a second side and wherein the third layer is arranged on the first side , the first layer is arranged on the third layer and the second layer is arranged on the first layer .24 . The packaging material according to claims19 to 23 , wherein the second layer comprises 1 layer of water-vapor and / or oil-grease barrier at 1 to 20 g / m2, or 2 to 15 g / m2, or 3 to 10 g / m2.25 . The packaging material according to claims20 to 24 , wherein the third layer compri ses 1 layer o f water-vapor and / or oil-grease barrier at 1 to 20 g / m2, or 2 to 15 g / m2, or 3 to 10 g / m2.26 . The packaging material according to claims 18 to 25 , wherein the alpha- 1 , 3-glucan or a substituted derivative thereof has a molecular weight o f 70 000 to 5 400 000 g / mol , or 100 000 to 5 000 000 g / mol or 200 000 to 4 000 000 g / mol .

27. The packaging material according to claims18 to 26, wherein the alpha-1 , 3-glucan or a substituted derivative thereof is represented by the structure,wherein Ri, R2 and R3 are independently H, and wherein n is at least 200.

28. The packaging material according to claims 27, wherein n is 200 to 2000, or 400 to 1500, or 500 to 1000, or 700 to 900.

29. Use of alpha-1 , 3-glucan or a substituted derivative thereof as an oxygen barrier on a paper, board, or the like.

30. The use according to claim 29, wherein the alpha-1 , 3-glucan or a substituted derivative thereof has a molecular weight of 70 000 to 5 400 000 g / mol, or 100 000 to 5 000 000 g / mol or 200 000 to 4 000 000 g / mol.

31. The use according to claim 29 or 30, wherein the alpha-1 , 3-glucan or a substituted derivative thereof is represented by the structure,wherein Ri, R2 and R3 are independently H, and wherein n is at least 200.32 . The use according to claim 31, wherein n is 200 to 2000, or 400 to 1500, or 500 to 1000 or 700 to 900.

33. The use according to claims 29 to 32 wherein the paper, board, or the like is kraft paper cardboard, paperboard and / or corrugated board.

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