Multilayer product and method for producing same

Abstract

A multilayer product is disclosed. The multilayer product may include a cellulose fiber-based base layer and a barrier layer. The barrier layer may include at least 10% (w / w) of hydrolyzed cellulose fibers.

Description

Technical Field

[0001] The present disclosure relates to a multi-layer product and a method of producing the multi-layer product. Background Art

[0002] The demand for packaging materials is growing significantly. Renewable, recyclable and biodegradable packaging solutions are needed.

[0003] Cellulose, for example in the form of cellulose fibers or pulp, is a renewable and biodegradable material that is well suited for packaging solutions. However, plastic materials or other less environmentally friendly materials may often be required, for example as a coating, to impart barrier properties to packaging materials formed primarily from cellulose. Such packaging materials are not fully biodegradable, and their recycling can be complicated. Summary of the invention

[0004] A multi-layer product is disclosed. The multi-layer product may include a base layer based on cellulose fibers and a barrier layer. The barrier layer may contain at least 10% (w / w) hydrolyzed cellulose fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The accompanying drawings are included to provide a further understanding of the embodiments and constitute a part of this specification, and illustrate various embodiments. In the drawings:

[0006] Figure 1A One embodiment of a multilayer product 1 is shown in cross-sectional view;

[0007] Figure 1B Another embodiment of a multi-layer product is described;

[0008] Figure 1C Another embodiment of a multi-layer product is described;

[0009] Figure 1D Yet another embodiment of a multi-layer product is described;

[0010] Figure 1E Yet another embodiment of a multi-layer product is described;

[0011] Figure 2A Apparent bulk density values ​​for specific fiber blends are shown;

[0012] Figure 2B The tensile index values ​​for specific fiber blends are shown;

[0013] Figure 2C shows the strain-at-break values ​​for a particular fiber blend; and

[0014] Figure 3 Air permeability measurements of the multilayer structures are shown. DETAILED DESCRIPTION

[0015] A multi-layer product is disclosed.

[0016] The multi-layer product may comprise a base layer based on cellulose fibres and a barrier layer.The barrier layer may comprise at least 10% (w / w) hydrolyzed cellulose fibres.

[0017] The hydrolyzed cellulose fibers are a moldable material and when the barrier layer material comprising the hydrolyzed cellulose fibers is densified, for example by compression, a material layer with low porosity can be obtained. The hydrolyzed cellulose fibers may have surface closing properties. For example, by calendering, a very dense structure can be obtained from the barrier layer material. Such a layer may have barrier properties. For example, it may be a gas (oxygen) barrier and / or a grease barrier (e.g. an oil barrier).

[0018] The base layer may act as a support layer, ie it may provide mechanical strength to the multi-layer product.

[0019] Both the base layer and the barrier layer can be formed from cellulose-based materials. In other words, the barrier layer can also be based on cellulose fibers.

[0020] The composition of the base layer and the barrier layer can be selected so that the strength and density of the multilayer product can be optimized as desired. The composition of the barrier layer can also be selected so that the desired barrier properties are obtained.

[0021] Such multilayer products do not necessarily require, for example, plastic coatings or other non-cellulose based layers or coatings. For example, barrier properties have traditionally been achieved using fluorinated compounds, which are, for example, harmful to the environment and may be phased out in the future. Avoiding or reducing the need to use additional layers or coatings to achieve barrier properties may be very useful, for example for environmental reasons. Multilayer products according to one or more embodiments described in this specification may be biodegradable and capable of being relatively easily recycled using existing processes. For example, up to 50% of the cellulose fibers in the multilayer product may be recovered in a recycling process. The multilayer product may be compostable. The multilayer product may be burnt, and may burn relatively cleanly.

[0022] The barrier layer may at least partially cover the base layer, or the base layer may at least partially cover the barrier layer.

[0023] The barrier layer and the base layer may be connected to each other directly or through one or more additional layers or media such as adhesives.

[0024] The barrier layer and the base layer may at least partially overlap, or the barrier layer and the base layer may completely overlap.

[0025] The barrier layer may or may not be the outermost layer of the multi-layer product. According to an embodiment, both sides of the barrier layer may be covered by other layers.

[0026] The multi-layer product may comprise at least two layers, for example two layers, three layers or more layers.

[0027] The multi-layer product may comprise at least one barrier layer.

[0028] The multi-layer product may comprise at least one base layer.

[0029] The multi-layer product may comprise at least one barrier layer and at least one base layer.

[0030] The multilayer product may also include additional layers. For example, the multilayer product may include an intermediate layer (or at least one intermediate layer) between the base layer and the barrier layer. Such an intermediate layer may also be based on cellulose fibers. However, its composition may be different from that of the base layer and / or the barrier layer. The multilayer product may include two or more base layers, and / or two or more barrier layers.

[0031] The multi-layer product may comprise a base layer and two barrier layers, the barrier layers being arranged on opposite sides of the base layer.

[0032] The multi-layer product may include one barrier layer and two base layers, the base layers being arranged on opposite sides of the barrier layer.

[0033] The barrier layer may be a dense and / or compressed layer. In other words, the barrier layer may be a dense and / or compressed layer.

[0034] The base layer may be dense and / or compressed. In other words, the base layer may be a dense and / or compressed layer.

[0035] Both the barrier layer and the base layer may be densified and / or compressed.

[0036] Densification can be performed, for example, by wet calendering or dry calendering. Wet calendering can further improve densification.

[0037] However, compression or densification may not always be necessary to achieve the desired barrier properties. For example, the barrier layer can be formed by spraying the material of the barrier layer onto the base layer (or, in some embodiments, onto another additional layer). As another example, the barrier layer and the base layer (and any additional layers, if present) can be formed, for example, in a double-layer or multi-layer headbox of a paper or board machine.

[0038] Densification and / or compression can provide, for example, a certain oxygen transmission rate to the multilayer product. Densification and / or compression can provide, for example, a certain smoothness to the barrier layer.

[0039] The multilayer product may be a moldable product or a molded product.

[0040] The moldable multilayer product can be, for example, a sheet or a flat structure. Such a moldable multilayer product can be molded into a final form having a desired shape. Various methods can be used to mold the multilayer product.

[0041] The molded multilayer product may be, for example, a container or a receptacle, such as a cup or a plate. However, the shape of the molded multilayer product is not particularly limited.

[0042] The multilayer product can be flexible or a flexible multilayer product. The multilayer product can also be rigid or a rigid multilayer product.

[0043] The multilayer product may be, for example, a packaging material, a packaging paper, a wrapping paper, a protective paper, a packaging board, a packaging 3D material, a decorative paper, an envelope or a release liner.

[0044] The multilayer product may be formed mainly of cellulose-based materials. However, in such a multilayer product, the presence of a small amount of non-cellulose-based materials is not necessarily excluded. For example, a multilayer product formed mainly of cellulose-based materials may contain, for example, a non-cellulose-based adhesive, such as at least one of glue, additives, pigments or inks.

[0045] In some embodiments, the multi-layered product may be formed entirely from cellulose-based materials.

[0046] In the context of the present specification, the term "mainly formed of cellulose-based material" may refer to a multilayer product in which at least 85% (w / w), or at least 95% (w / w), or at least 98% (w / w), or at least 99% (w / w) or 100% (w / w) of the material is cellulose-based material.

[0047] The multi-layer product may be biodegradable.The multi-layer product may be biodegradable as determined by OECD Chemical Testing Standard 301F.

[0048] In at least some embodiments, the term "biodegradable" may refer to readily biodegradable according to OECD chemical substance testing standard 301F (manometric respiratory test). A readily biodegradable multilayer product may be a multilayer product that reaches at least 60% biodegradation within 28 days according to OECD chemical substance testing standard 301F.

[0049] Multi-layer products may be recyclable.

[0050] The base layer may include a reinforcing component. The reinforcing component may include, for example, cellulose fibers or may be, for example, cellulose fibers. Such cellulose fibers may be cellulose fibers that can impart reinforcing properties to a multilayer product. For example, they may be unmodified and / or unhydrolyzed. In other words, the reinforcing component of the base layer may be a cellulose fiber, such as an unmodified and / or unhydrolyzed cellulose fiber. The CED viscosity of the cellulose fibers of the base layer may be greater than 500 ml / g, for example, in the range of about 500 to 3000 ml / g. In some embodiments, the CED viscosity of the cellulose fibers of the base layer may be, for example, in the range of 800 to 1200 ml / g, or in the range of 900 to 1100 ml / g.

[0051] The fibers of the cellulose fibers (including the hydrolyzed or non-hydrolyzed cellulose fibers of the barrier layer, base layer and / or any additional layer or reinforcing component containing cellulose fibers) can be natural fibers, such as lignocellulose fibers, cellulose fibers, cellulose fiber derivatives, wood derivatives or any combination or mixture thereof. The fibers in the cellulose fibers can be natural source fibers, such as modified natural source fibers, and / or cellulose-based fibers. The fibers in the cellulose fibers can be virgin, regenerated or secondary natural fibers, or any mixture or combination thereof. The cellulose fibers can be, for example, short fibers. The cellulose fibers can be fibers derived from, for example, cotton or cotton linter. The cellulose fibers can include, for example, pulp or be, for example, pulp. The pulp can include or be, for example, wood pulp (such as hardwood and / or softwood pulp), non-wood pulp and / or agricultural pulp (agropulp). The pulp can be a chemical pulp, such as kraft pulp, soda pulp, sulfate pulp or organic solvent pulp. The pulp may be mechanical and thermal pulp (TMP), mechanical pulp (ground wood (GW), pressure ground wood (PGW), refined mechanical pulp (RMP)) and / or chemithermomechanical pulp (CTMP). Additionally or alternatively, the pulp may be an undried pulp, such as an undried kraft pulp. The cellulose fibers or pulp may include or may be regenerated fibers. The fibers in the cellulose fibers may include or may be at least one of wood pulp, non-wood pulp, short fibers, regenerated fibers, or any mixture or combination thereof. In some embodiments, the fibers in the cellulose fibers may not include man-made fibers and / or oil-based fibers. Short fibers having a desired length may be combined with other types of reinforcing components, such as other types of cellulose fibers.

[0052] In the context of the present specification, the term "non-hydrolyzable cellulose fibers" may refer to cellulose fibers that have not been intentionally subjected to a large amount of chemical hydrolysis. However, non-hydrolyzable cellulose fibers may be, for example, chemical pulp, such as kraft pulp, and may, for example, be bleached during the production of chemical pulp. Although, for example, the kraft pulping process may result in slight hydrolysis of the cellulose fibers, chemical pulp may still be considered to be or contain non-hydrolyzable cellulose fibers.

[0053] The reinforcing component, or other cellulosic fibers, may be or include chemical pulp, such as kraft pulp, sulfate pulp, and / or organosolv pulp; and / or staple fibers.

[0054] Other cellulosic fibers (eg, of the reinforcing component) may include or may be natural and / or man-made cellulosic fibers having a CED viscosity in the range of 500-3000 ml / g. Man-made cellulosic fibers may, at least in some embodiments, have a lower CED viscosity.

[0055] In the context of the present disclosure, the term "hydrolyzed cellulose fibers" may be understood to refer to cellulose fibers that have been subjected to a treatment that has at least partially hydrolyzed the cellulose chains of the cellulose fibers, for example compared to comparable unhydrolyzed cellulose fibers. Therefore, the average length of the cellulose chains of the hydrolyzed cellulose fibers may be less than the average length of the cellulose chains of comparable unhydrolyzed cellulose fibers. Certain properties of cellulose fibers, such as CED viscosity, may be affected by hydrolysis. The hydrolyzed cellulose fibers (may) be subjected to enzymatic hydrolysis of the cellulose fibers for 2-3 hours, for example, using a cellulolytic enzyme. The hydrolyzed cellulose fibers may be, for example, hydrolyzed pulp or include, for example, hydrolyzed pulp. In this article, the pulp of the hydrolyzed pulp may be any pulp described in this specification.

[0056] The CED viscosity of the hydrolyzed cellulose fibers may range from 50 to 500 ml / g, or from 50 to 400 ml / g. In some embodiments, the CED viscosity of the hydrolyzed cellulose fibers may range from 120 to 300 ml / g, or from 140 to 200 ml / g.

[0057] The term "CED viscosity" may be understood to mean the limiting viscosity number in copper ethylenediamine (CED) solution. The CED viscosity may be measured, for example, according to the ISO 5351:2010 standard.

[0058] The degree of polymerization (DP) of the hydrolyzed cellulose fibers may range from about 100 to 700, or from about 120 to 300. The degree of polymerization may be measured, for example, using standard ISO 5351:2010 (en). The degree of polymerization (DP) may be estimated from the CED viscosity value obtained according to the standard as follows:

[0059] DP=0.75[μ]1 / 0.905 , where [μ] is the CED viscosity value.

[0060] In some embodiments, the hydrolyzed cellulose fibers may be obtained by pretreatment or modification, such as surface modification, saponification of cellulose esters, or phosphorylation. The hydrolyzed cellulose fibers may have traces of processes that resulted in, for example, changes in surface chemistry.

[0061] The barrier layer is formed of a material comprising at least 10% (w / w) hydrolyzed cellulose fibers. The barrier layer, i.e. the material of the barrier layer, may contain, for example, at least 20% (w / w), or at least 30% (w / w), or at least 40% (w / w), or at least 50% (w / w), or at least 60% (w / w), or at least 70% (w / w), or at least 80% (w / w), or 100% (w / w) hydrolyzed cellulose fibers. The barrier layer, i.e. the material of the barrier layer, may be a mixture comprising hydrolyzed cellulose fibers and other (i.e. cellulose fibers of the reinforcing component and / or non-hydrolyzed) cellulose fibers. The other cellulose fibers may be any cellulose fibers described in the present specification, in particular any cellulose fibers described as reinforcing components. The properties of the hydrolyzed cellulose fibers and the other cellulose fibers (e.g. degree of polymerization and / or CED viscosity) may be different from each other. The proportions of the hydrolyzed cellulose fibers and the other cellulose fibers and optional other components may be selected so that the properties of the barrier layer meet the requirements. For example, increasing the proportion of hydrolyzed cellulose fibers can increase the density of the barrier layer, which in turn can reduce the permeability to, for example, grease and / or oxygen. The proportion of hydrolyzed cellulose fibers can therefore be selected to achieve a desired density, desired barrier properties, and / or desired smoothness. Other cellulose fibers, such as cellulose fibers of a reinforcing component (if present), can be provided in a desired proportion, for example, to provide the barrier layer with desired strength and / or other properties.

[0062] The barrier layer comprising hydrolyzed cellulose fibers can be densified or compressed to have a desired density. Such a barrier layer can have improved barrier properties and smoothness.

[0063] A proportion of at least 10% (w / w) of hydrolyzed cellulose fibres is understood to be the dry weight of hydrolyzed cellulose fibres based on the total dry weight of the mixture and / or the total dry weight of the layer.

[0064] The barrier layer, ie the material of the barrier layer, may comprise about 10 to 90% (w / w) of hydrolyzed cellulose fibers and about 10 to 90% (w / w) of other cellulose fibers.

[0065] The barrier layer, ie the material of the barrier layer, may comprise about 10 to 50% (w / w) of hydrolyzed cellulose fibers and about 50 to 90% (w / w) of other cellulose fibers.

[0066] The weight ratio of the hydrolyzed cellulose fibers to the other cellulose fibers may be in the range of about 10:90 to about 50:50, or in the range of about 40:60 to about 20:80.

[0067] The multi-layer product may also include a surface chemical for providing barrier properties. The surface chemical may be applied to the multi-layer product. The surface chemical for providing barrier properties may include or may be starch, wax, fatty acid, alkyl ketene dimer, alkyl succinic anhydride, thermoplastic component, or any combination or mixture thereof. The surface chemical may or may not chemically react with the cellulose of the cellulosic fibers; this may depend on its chemical nature. The surface chemical may be physically attached to the cellulose. For example, it may impregnate the barrier layer and / or the base layer and provide the desired physical properties to the multi-layer product.

[0068] The multi-layer product may also include a coating layer overlying the barrier layer and / or the base layer.

[0069] The coating may be the outermost layer of a multi-layer product.

[0070] The coating can be, for example, a hot melt coating, a dip coating, or a carton coating, or can be applied as, for example, a hot melt coating, a dip coating, or a carton coating. Such coatings, such as hot melt coatings, can improve the heat sealing properties of multi-layer products.

[0071] The multilayer product may further include an adhesive layer between the base layer and the barrier layer. The multilayer product may include an adhesive layer (or another adhesive layer) between one or more other layers. The adhesive layer may connect the base layer and the barrier layer and / or any other layer (depending on the embodiment and the presence and arrangement of the layers) to each other. The adhesive may be, for example, a bio-based and / or biodegradable adhesive, such as a bio-based and / or biodegradable glue.

[0072] The multi-layer product may further comprise an ink and / or paint layer. The ink and / or paint layer may be formed, for example, by printing ink or painting on the surface of the multi-layer product.

[0073] The base layer may be formed from a densified mixture of cellulose fibers.

[0074] The substrate may comprise at least 50% (w / w) kraft pulp and / or mechanical pulp and 50% (w / w) or less hydrolyzed cellulose fibers.

[0075] The substrate, ie the material of the substrate, may comprise about 50 to 90% (w / w) kraft pulp and / or mechanical pulp, and about 10 to 50% (w / w) hydrolyzed cellulose fibers.

[0076] The substrate, ie the material of the substrate, may comprise about 60 to 80% (w / w) kraft pulp and / or mechanical pulp, and about 20 to 40% (w / w) hydrolyzed cellulose fibers.

[0077] The base layer may comprise 100% non-hydrolyzed cellulosic fibers, such as kraft pulp and / or mechanical pulp.

[0078] The weight ratio of hydrolyzed cellulose fibers to non-hydrolyzed cellulose fibers in the base layer may range from about 10:90 to about 50:50.

[0079] The weight ratio of hydrolyzed cellulose fibers to non-hydrolyzed cellulose fibers in the base layer may range from about 20:80 to about 40:60.

[0080] The weight of the base layer may be, for example, at least 20 gsm, or in the range of 20-800 gsm, or in the range of 40-800 gsm (grams per square meter).

[0081] The thickness of the barrier layer may be 300 μm or less, or in the range of 1-200 μm, or in the range of 10-100 μm, or in the range of 10-40 μm.

[0082] The base layer and the barrier layer may be separated from each other mechanically. Such separation may be used, for example, for recycling purposes. The layers may be mechanically separable, for example, depending on the manufacturing process used to prepare the multilayer product and / or on the presence and type of additives contained in the multilayer product. The separability of the base layer and the barrier layer may depend, for example, on the presence and composition of an adhesive layer arranged between the base layer and the barrier layer. The base layer and the barrier layer may be separated, for example, in a pulper, where they may be separated by suspending them in water to form particles and then separating the particles based on density.

[0083] In some embodiments, the multi-layer product may not contain any plastic and / or metal. In some embodiments, the multi-layer product may not contain inorganic materials, such as pigments.

[0084] The oxygen transmission rate of multi-layer products can be 1000cm 3 / (m 2 ·day) or less. The oxygen transmission rate of multi-layer products can be 100cm 3 / (m 2 ·day) or lower, or 10cm 3 / (m 2·day) or less. The oxygen permeability can be measured at 23°C and 50% relative humidity. The oxygen permeability can be measured using a MOCON OX-TRAN@ instrument. The instrument design operation can comply with the ASTM D 3985 standard. In some embodiments, the oxygen permeability can be measured using a Mocon Ox-Tran 2 / 21MH instrument according to one of the standards ASTM D3985, ASTM F1927, or ISO 15105-2. In one embodiment, the oxygen permeability is measured at 23°C and 0% relative humidity, 100% O2 using a MOCON OX-TRAN instrument according to the ASTM D 3985 standard.

[0085] The Bendtsen air permeability of the multilayer product (i.e. the air permeability measured using a Bendtsen tester) may be 100 ml / min or less. The Bendtsen air permeability of the multilayer product may be 20 ml / min or less, or 5 ml / min or less. The Bendtsen air permeability value may be measured, for example, according to standard ISO 5636-3.

[0086] The composition of the multi-layer product, such as the presence or absence of surface chemicals, or densification and / or compression, may have a significant impact on water vapor permeability and oil permeability (e.g., as measured by heptane vapor transmission rate.) Therefore, for multi-layer products according to various embodiments described herein, the values ​​of such parameters may vary significantly.

[0087] The water vapor permeability of a multilayer product can be, for example, 1000 g / (m 2 ·day) or less, or 100g / (m 2 ·day) or less, or 20g / (m 2 Water vapor permeability can be measured at 23°C and 50% relative humidity.

[0088] Multilayer products may have a g / (m 2 ·day) or less, or 20g / (m 2 ·day) or lower, or 10g / (m 2 ·day) or less. The heptane vapor transmission rate can be measured at 23°C and 50% relative humidity.

[0089] The multilayer product may be semi-transparent and / or translucent. This may depend, for example, on the composition of the base layer. The base layer may be densified to the extent of being semi-translucent and / or translucent. The product may have a light transmittance in the range of 0 to 70%, or in the range of 1 to 70% or 20 to 70%. Light transmittance may be understood to refer to visible light transmittance. Light transmittance may be measured, for example, using an optical profilometer.

[0090] A method for producing a multilayer product according to one or more embodiments described in this specification is disclosed.

[0091] The method may include forming a base layer and a barrier layer, and forming a multilayer product therefrom, for example by attaching the base layer and the barrier layer (and optionally one or more additional layers) to one another.

[0092] The method may include providing a material for a barrier layer and a material for a base layer; forming the base layer and the barrier layer, and thereby forming a multi-layer product. The material and composition of the material for the barrier layer and the base layer may be in accordance with one or more embodiments described in this specification.

[0093] The method may comprise forming the base layer and the barrier layer simultaneously, thereby forming a multilayer product. The base layer and the barrier layer may be formed simultaneously, for example in a double or multilayer headbox of a paper or board machine. If desired, additional layers may be formed simultaneously, or they may be attached to the multilayer product. The resulting web forming the base layer and the barrier layer (and optional additional layers) may be densified or compressed, for example, by calendering. Densification may be performed, for example, by wet calendering or dry calendering. Wet calendering may further improve densification.

[0094] In some embodiments, a base layer can be formed; the barrier layer material comprising hydrolyzed cellulose fibers can be formed into a web, and the web can be calendered to form the barrier layer; and the barrier layer can be applied to the base layer, optionally with an adhesive layer applied between the base layer and the barrier layer.

[0095] The web (which may form the barrier layer and / or the base layer and the barrier layer) may be calendered. Calendering may be performed using, for example, a nip pressure of 3 to 350 kN / m.

[0096] In some embodiments, the barrier layer may be formed by spraying the material of the barrier layer onto the base layer (or, in some embodiments, onto another additional layer).

[0097] The method may further comprise moulding the product. The product may be moulded from, for example, a dry web.

[0098] Example

[0099] Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings.

[0100] The following description discloses some embodiments in detail so that those skilled in the art can utilize these embodiments based on the present disclosure. Not all steps or features of the embodiments are discussed in detail because many steps or features are obvious to those skilled in the art based on the present description.

[0101] Figure 1A An embodiment of a multilayer product 1 is depicted in a cross-sectional view. The multilayer product 1 comprises a base layer 2 based on cellulose fibers and a barrier layer 3. The barrier layer 3 at least partially covers the base layer 2, or Figure 1A As shown, the base layer 2 is completely covered.

[0102] Figure 1B Another embodiment of a multilayer product 1 is described. The multilayer product 1 is similar to Figure 1A The multilayer product 1 is similar to the product shown in , except that the multilayer product 1 further comprises a coating 4. The coating may be, for example, a plastic coating. In some embodiments, the coating 4 may comprise, for example, a surface chemical, such as a wax, or any other surface chemical described in this specification. The coating 4 is disposed on the barrier layer 3. It at least partially covers the barrier layer 3, or as Figure 1A As shown, the barrier layer 3 is completely covered. However, as will be appreciated by those skilled in the art, the coating 4 may be disposed on the base layer 2 in addition or in lieu thereof. It will also be appreciated by those skilled in the art that the coating 4 may also be included in the base layer 2. Figure 1C to Figure 1E In any of the embodiments shown.

[0103] Figure 1C Another embodiment of a multilayer product 1 is described. The multilayer product 1 is similar to Figure 1A The product shown in FIG. 1 is different in that the multilayer product 1 comprises three layers: a base layer 2 and two barrier layers 3 and 3 ′. The barrier layers 3 and 3 ′ are arranged on opposite sides of the base layer 2 .

[0104] Figure 1D A further embodiment of a multilayer product 1 is described. The multilayer product 1 is similar to Figure 1C The product shown in , differs in that the multilayer product 1 comprises three layers: two base layers 2 and 2 ′, and a barrier layer 3. The base layers 2 and 2 ′ are arranged on opposite sides of the barrier layer 3.

[0105] Figure 1E A further embodiment of a multilayer product 1 is described. The multilayer product 1 is similar to Figure 1A The multilayer product 1 is different from the product shown in , except that the multilayer product 1 further includes an adhesive layer 5 located between the base layer 2 and the barrier layer 3. The adhesive layer 5 extends between the base layer 2 and the barrier layer 3, and can attach the base layer 2 and the barrier layer 3 to each other. The adhesive in the adhesive layer 5 can be, for example, any adhesive described in this specification.

[0106] Figures 1A to 1E The exemplary embodiments shown are flat or sheet-like and may be moldable into a desired shape.

[0107] Example 1

[0108] The physical and mechanical properties of mixtures containing kraft softwood pulp fibers and hydrolyzed kraft softwood pulp fibers with different CED viscosities were evaluated. Pulp 1 refers to hydrolyzed kraft softwood pulp fibers with a CED viscosity of 166 ml / g, and pulp 2 refers to hydrolyzed kraft softwood pulp fibers with a CEE viscosity of 200 ml / g. Formulation x:y represents the dry weight fiber mixture with kraft softwood pulp fibers: pulp 1 or pulp 2. For example, 60:40 represents a formulation with 60% kraft softwood pulp fibers and 40% pulp 1 or pulp 2. The physical and mechanical properties of the formulations are as follows: Figure 2A , 2B and 2C.

[0109] Figure 2A Apparent bulk density values ​​are shown for specific fiber blends.

[0110] Figure 2B The tensile index values ​​for specific fiber blends are shown.

[0111] Figure 2C The strain-at-break values ​​for specific fiber blends are shown.

[0112] Example 2

[0113] Multilayer sheets of two or three layer combinations were produced by combining the softwood base layer with pulp 1 (hydrolyzed kraft softwood pulp fibers with a CED viscosity of 166 ml / g) in different combinations. For example, a two-layer sheet was produced by stacking the softwood base layer with a pulp 1 layer. For three layers, the pulp 1 layer was sandwiched between two softwood layers. The air permeability of the resulting multilayer structure was measured according to ISO 5636-3, as Figure 3 shown.

[0114] It is obvious to a person skilled in the art that, as technology develops, the basic idea can be implemented in various ways. Therefore, the implementations are not limited to the above-described embodiments; instead, they may vary within the scope of the claims.

[0115] The embodiments described above can be used in any combination with each other. Several embodiments can be combined to form further embodiments. The methods, products or uses disclosed herein may include at least one embodiment described above. It is understood that the above benefits and advantages may relate to one embodiment, or may relate to several embodiments. The embodiments of the present invention are not limited to embodiments that can solve any or all of the problems described, nor are they limited to embodiments that have any or all of the benefits and advantages described. It should be further understood that the "one" item mentioned refers to one or more items therein. The term "comprising" used in this specification includes the features or behaviors thereafter, without excluding the presence of one or more other features or behaviors.

Claims

1. A multilayer product (1) comprising a base layer (2) based on cellulose fibers and a barrier layer (3), wherein the barrier layer comprises at least 10% (w / w) hydrolyzed cellulose fibers.

2. The multilayer product according to claim 1, wherein Both the base layer and the barrier layer are formed from cellulose-based materials.

3. The multilayer product according to claim 1 or 2, wherein: The multi-layer product is a packaging material, a packaging paper, a wrapping paper, a protective paper, a packaging board, a packaging 3D material, a decorative paper, an envelope or a release liner.

4. The multilayer product according to any one of claims 1 to 3, wherein The multi-layer product is primarily formed from a cellulose-based material.

5. The multilayer product according to any one of claims 1 to 4, wherein The multi-layer product is determined to be biodegradable according to OECD Chemical Substance Testing Standard 301F.

6. The multilayer product according to any one of claims 1 to 5, wherein The hydrolyzed cellulose fibers have a CED viscosity in the range of 50-500 ml / g, or in the range of 120-300 ml / g, or in the range of 140-200 ml / g.

7. The multilayer product according to any one of claims 1 to 6, wherein The multi-layer product also includes a surface chemical applied to the multi-layer product to provide barrier properties, or a coating (4) covering the barrier layer.

8. The multilayer product according to any one of claims 1 to 7, wherein The multilayer product further comprises an adhesive layer (5) located between the base layer and the barrier layer.

9. The multilayer product according to any one of claims 1 to 8, wherein The substrate is formed from a densified cellulosic fibre mixture, optionally comprising at least 50% (w / w) kraft pulp and / or mechanical pulp and 50% (w / w) or less hydrolysed cellulosic fibres.

10. The multilayer product according to any one of claims 1 to 9, wherein The weight of the base layer is in the range of 20 gsm to 800 gsm.

11. The multilayer product according to any one of claims 1 to 10, wherein The thickness of the barrier layer is 300 μm or less, or in the range of 1-200 μm, or in the range of 10-100 μm, or in the range of 10-40 μm.

12. The multilayer product according to any one of claims 1 to 11, wherein The multi-layer product does not contain any plastic or metal.

13. The multilayer product according to any one of claims 1 to 12, wherein The oxygen permeability of the multilayer product is 1000 cm 3 / (m 2 ·day) or lower, or 100cm 3 / (m 2 ·day) or lower, or 10cm 3 / (m 2 · days) or lower.

14. The multilayer product according to any one of claims 1 to 13, wherein The multi-layer product has a Bendtsen air permeability of 100 ml / min or less, or 20 ml / min or less, or 10 ml / min or less.

15. A method of producing a multi-layer product according to any one of claims 1 to 14, the method comprising forming a base layer and a barrier layer, thereby forming a multi-layer product, or simultaneously forming a base layer and a barrier layer, thereby forming a multi-layer product.

16. The method of claim 15, wherein: forming a base layer; forming a barrier layer material comprising hydrolyzed cellulose fibers into a web, calendering the web to form a barrier layer; applying the barrier layer to the base layer, and optionally applying an adhesive layer between the base layer and the barrier layer.

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