Oxygen barrier material

Abstract

The invention relates to a method for producing an oxygen barrier material, comprising: providing a support layer comprising paper and a first coating, applying a second coating on the support layer by extrusion technique, thereby forming a second coating on the support layer, the second coating having a gram weight of between 5 and 50 g / m2, where the second coating is compostable and / or biodegradable in industrial compost, the first coating is made to be at least 90% biodegradable within 6 months, the polymeric material in the first coating is biodegradable, the oxygen barrier material is compostable, and the oxygen barrier material has an oxygen barrier value of less than 70 cc / m2 * day. The invention also relates to an oxygen barrier material.

Description

Technical Field

[0001] This specification relates to a method for manufacturing an oxygen barrier material. This specification also relates to an oxygen barrier material. Background Art

[0002] In industrial production, there are many types of barrier materials. For example, in the case of packaging materials, the characteristics of the product to be packaged and the expected shelf life usually determine the packaging material used for each product.

[0003] To achieve the desired barrier properties, materials can be selected. For example, if good water resistance and good oxygen barrier properties are required, the barrier laminate can contain a layer of material with excellent water resistance and a layer of material with excellent oxygen barrier properties. However, the industry still needs new barrier materials. Summary of the Invention

[0004] The present invention aims to provide an oxygen barrier material and a method for manufacturing the oxygen barrier material.

[0005] The various aspects of the invention are characterized by what is stated in the independent claims. Preferred embodiments are disclosed in the dependent claims. These and other embodiments are disclosed in the description and drawings.

[0006] This specification provides a solution for obtaining fiber-based oxygen barrier materials by extrusion coating.

[0007] A method of making an oxygen barrier material may include the following steps:

[0008] - Provide density equal to or less than 1000kg / m 3 , preferably at 800kg / m 3 Up to 990kg / m 3 between, more preferably less than 940kg / m 3 A support layer, the support layer comprising:

[0009] - paper comprising natural fibers comprising cellulose, and

[0010] - a first coating on at least one surface of the paper, the first coating comprising a binder,

[0011] The first coating has a gram weight between 2 and 10 gsm.

[0012] - applying a second coating on one or both sides of the support layer by extrusion technology, thereby forming a second coating on one or both sides of the support layer, the gram weight of the second coating being between 5 and 50 gsm,

[0013] in

[0014] A) the second coating is compostable and / or biodegradable in an industrial compost, thereby being at least 90% biodegradable within 6 months, as determined according to standard EN 13432, and

[0015] - the polymeric material in the first coating is biodegradable according to standard OECD 301, and

[0016] - oxygen barrier materials are compostable according to standard EN 13432,

[0017] and

[0018] B) The oxygen barrier value of the oxygen barrier material is less than 70cc / m 2 *Day, preferably less than 50cc / m 2 *day, more preferably less than 20cc / m 2 *Days, measured according to ISO 15105-2 at 23°C / 50% relative humidity.

[0019] Oxygen barrier materials may include:

[0020] - Density equal to or less than 1000 kg / m 3 , preferably at 800kg / m 3 Up to 990kg / m 3 between, more preferably less than 940kg / m 3 A support layer, the support layer comprising:

[0021] - paper comprising natural fibers, said natural fibers containing cellulose, and

[0022] - a first coating comprising an adhesive on at least one surface of the paper, the first coating having a grammage between 2 and 10 gsm, and

[0023] - a second coating on at least one side of the support layer, the second coating having a grammage between 5 and 50 gsm, wherein

[0024] A) the second coating is compostable and / or biodegradable in an industrial compost, thereby being at least 90% biodegradable within 6 months, as determined according to standard EN 13432, and

[0025] - the polymeric material in the first coating is biodegradable according to standard OECD 301, and

[0026] - oxygen barrier materials are compostable according to standard EN 13432,

[0027] and

[0028] B) The oxygen barrier value of the oxygen barrier material is less than 70cc / m 2*Day, preferably less than 50cc / m 2 *day, more preferably less than 20cc / m 2 *Days, measured according to ISO 15105-2 at 23°C / 50% relative humidity.

[0029] The second coating is preferably located on the same side as the first coating and is located above the first coating. The technical effect is to achieve a higher oxygen barrier. Preferably, the second coating is located directly on the first coating. However, a tie layer may be present between the first and second coatings to improve adhesion between the first and second coatings. Regardless of the presence of a tie layer, the adhesion is preferably adjusted so that the adhesion between the support layer and the second coating is sufficient for converting, but the support layer and the second coating can be separated (even manually).

[0030] Therefore, the second coating and the first coating are preferably located on the first side of the paper. The oxygen barrier material may further comprise a third coating located on the second side of the paper. The third coating may comprise or consist of starch. The third coating preferably comprises 80% or more starch by weight, based on the total dry weight of the third coating. The third coating preferably has a grammage of 0.5-1.5 gsm, more preferably 0.7-1.3 gsm, and even more preferably 0.8-1.2 gsm.

[0031] The oxygen barrier property of the support layer may be equal to or greater than 500 cc / m 2 *Day, preferably equal to or greater than 1000cc / m 2 *Day, most preferably greater than 5000cc / m 2 * days. Alternatively or in addition, the oxygen barrier of the second coating may be greater than 90 cc / m 2 *Day, preferably equal to or greater than 100cc / m 2 *Day, most preferably greater than 150cc / m 2 *day. The technical effect is to improve the barrier properties of oxygen barrier materials in a cost-effective manner. Another technical effect is to provide environmentally friendly materials because these layers can use materials that do not have high oxygen barrier properties.

[0032] The first coating layer may include a binder selected from the group consisting of starch, modified starch, enzymatically converted starch, polyvinyl alcohol, modified cellulose, biodegradable polyesters, and mixtures thereof. Preferably, the binder is selected from the group consisting of polyvinyl alcohol, starch, modified starch, enzymatically converted starch, modified cellulose, and mixtures thereof. Technical benefits of these materials include improved environmental friendliness.

[0033] In one advantageous embodiment, the second coating comprises at least one of the following: polybutylene succinate, polyhydroxyalkanoate, copolymers (dipolymers) or terpolymers of polylactic acid, glycolide, and / or lactide, and polybutylene adipate terephthalate. Preferably, the second coating comprises polybutylene succinate. The technical benefits of these materials include improved environmental friendliness, as they are at least industrially compostable, thereby making the entire oxygen barrier material structure industrially compostable.

[0034] The mineral oil barrier property (heptane vapor transmission rate) of the second coating can be less than 10g / m 2 * days. Alternatively or in addition, the support layer may have a mineral oil barrier (heptane vapor transmission rate) of at least 100 g / m 2 * days. In addition, the mineral oil barrier property (heptane vapor transmission rate) of the oxygen barrier material can be less than 2g / m 2 *day. The technical effect is to improve the mineral oil barrier properties of the resulting oxygen barrier material in a cost-effective manner. Another technical effect is to provide an environmentally friendly material, as bio-based materials that do not have high mineral oil barrier properties can be used for these layers.

[0035] The WVTR value of the support layer can be higher than 500g / m 2 * days. Alternatively or in addition, the WVTR value of the second coating may be higher than 100 g / m 2 * days. The WVTR value of oxygen barrier materials can be less than 100g / m 2 *Days. WVTR values ​​are measured at 23°C / 85% relative humidity according to ISO 2528. The technical effect is to provide environmentally friendly materials with good WVTR values ​​using bio-based materials.

[0036] The grease barrier performance of the support layer can be less than 2 hours. Alternatively or in addition, the grease barrier performance of the second coating layer can be less than 36 hours. The grease barrier performance of the oxygen barrier material can exceed 72 hours. The grease barrier performance is measured according to ASTM F119-82 using chicken fat at 40°C. This technical effect is to improve the grease barrier performance of the resulting oxygen barrier material in a cost-effective manner. Another technical effect is the provision of an environmentally friendly material, as these layers can utilize bio-based materials that do not have high grease barrier properties.

[0037] The transparency of the support layer can be less than 65%, preferably less than 50%, as determined according to standard DIN 53146. The technical effect is that energy is saved in paper production due to better dewatering properties.

[0038] The Gurley Hill air permeability of the support layer may be higher than 100 sec / 100 ml, preferably between 100 sec / 100 ml and 3000 sec / 100 ml.

[0039] The second coating layer can have a tailored adhesion to the support layer, which can be selected so that the second coating layer can be manually separated from the support layer at 23°C and 50% relative humidity without the fibers adhering to the second coating layer.

[0040] Surprisingly, materials with good oxygen barrier properties can be obtained even when extrusion coating a polymer with no or low oxygen barrier properties onto a substrate with no or low oxygen barrier properties.

[0041] In this application, the term "low oxygen barrier property" means an oxygen barrier rate exceeding 80cc / m 2 *Day, for example, more than 100cc / m 2 *Daily, usually more than 200cc / m 2 *sky.

[0042] The coating of the oxygen barrier material can be free of nanocellulose. This provides a nanocellulose-free approach to achieving the desired oxygen barrier value. Another technical benefit is reduced energy consumption during the manufacturing process.

[0043] The coating of the oxygen barrier material may be free of polyethylene, more preferably free of polyolefins. The technical effect is to obtain an environmentally friendly, polyethylene-free way to obtain the required oxygen barrier value.

[0044] The oxygen barrier material according to the present description may be a packaging material.

[0045] The solution according to the present specification can provide flexible or rigid packaging applications for food, beverages, and non-food products requiring oxygen barrier value. Preferably, the resulting oxygen barrier material can be customized to improve recyclability.

[0046] The oxygen barrier material comprises a first coating layer and a second coating layer, both of which may be composed of biodegradable materials.

[0047] The oxygen barrier materials described herein can be manufactured in an environmentally friendly manner, such that the oxygen barrier materials can be recycled and / or composted after use, for example. As is known to those skilled in the art, plastic pollution is a significant environmental burden. By replacing other packaging polymers with the first and second coatings described herein, many environmental issues can be addressed.

[0048] Thanks to this new oxygen barrier material, the desired oxygen barrier properties can be achieved in an environmentally friendly manner. Traditionally, the multilayered structures of plastic multilayer laminates and paper-plastic laminates with oxygen barrier properties have complicated their recyclability. However, this new material allows for higher fiber recovery rates during recycling.

[0049] Furthermore, due to the novel oxygen barrier material, the second coating layer can form a specific adhesion to the support layer that is sufficient to meet the requirements of processing changes and enables (even manual) separation of the support layer and the second coating layer.

[0050] Advantageously, the second coating is heat sealable at least at 120°C. More preferably, heat sealability is achieved at any temperature within the range of 100 to 200°C.

[0051] The coating in the oxygen barrier material is at least 90%, and preferably completely (100%), biodegradable and compostable within six months. For example, in industrial composting, at least 90% of the oxygen barrier material decomposes aerobically into carbon dioxide, water, and biomass, and the decomposition products are non-ecotoxic. The biodegradability and compostability of oxygen barrier materials can be determined according to standard EN 13432.

[0052] Natural ingredients that have not been chemically modified, such as wood, wood fiber, starch, and pulp, are considered biodegradable without the need for testing.

[0053] By selecting certain materials, the oxygen barrier material can also be home compostable so as to be at least 90% biodegradable in compost at 20-30°C within 6 months, as determined according to standard EN 13432. Other material options may even be biodegradable in water (EN ISO 14851, EN ISO 14852, EN ISO 17556, EN ISO 19679 / 18830 or EN ISO 22404) and / or meet the guidelines for ready biodegradability (according to OECD (1992), Test No. 301: Ready Biodegradability, OECD Guide to the Testing of Chemicals, Part 3, OECD Publishing, Paris). This applies, for example, to binders in the first coating, such as starch, modified starch, enzymatically converted starch, and polyvinyl alcohol, or combinations thereof, and, for example, to polyhydroxyalkanoates in the second coating, such as PHB, PHBV, PHBH, P3HB4HB, PCL, or certain lactic acid copolymers.

[0054] Biodegradability refers to the ability of organic compounds to decompose into carbon dioxide, water, elemental mineral salts, and biomass under aerobic conditions by microorganisms. Full compostability requires that a material is fully biodegradable, and that the decomposition products do not adversely affect the quality of the compost. For example, the decomposition products must not be ecotoxic.

[0055] The germination rate of plant species grown in compost containing the decomposed oxygen barrier material is advantageously greater than 90% compared to compost without decomposition products of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In the following, the present invention will be described in more detail with reference to the accompanying drawings, in which:

[0057] Figure 1a -d shows an example cross section of an oxygen barrier material,

[0058] Figure 2a-2b and Figure 3a-3b An example of a laminate structure comprising a support layer and a second coating layer is shown.

[0059] Figure 4 A simplified schematic diagram showing an example of oxygen barrier material fabrication,

[0060] Figure 5a shows a micrograph after the second coating has been removed from the support layer with the first coating, in which the shapes of the fibers and pigments pressed onto the film can be seen, but in reality, the separated second coating is free of fibers and pigments, and

[0061] Figure 5b A micrograph is disclosed after removal of a second coating layer from a support layer in the absence of a first coating layer, wherein considerable fibers and pigments remain on the surface of the second coating layer after removal from the support layer.

[0062] These drawings are intended to illustrate the general principles of the disclosed technical solutions. Therefore, the illustrations in the drawings are not necessarily to scale or imply the exact layout of the system components. DETAILED DESCRIPTION

[0063] In this document, reference is made to the accompanying drawings which have the following reference numerals and symbols:

[0064] 1 support layer, including base paper and first coating,

[0065] 2. Paper, namely base paper and uncoated paper,

[0066] 3 first coating,

[0067] 4 second coating,

[0068] 5 third coating,

[0069] 6 adhesive layers,

[0070] 7 first coating,

[0071] 8 Second coating,

[0072] 9 extruder,

[0073] 10 oxygen barrier materials, and

[0074] 11. First coating unit.

[0075] Terminology and standards

[0076] Unless otherwise stated, the following standards refer to the methods used to obtain the values ​​of the quality parameters of the packaging materials described:

[0077] 1) Weight ISO 536:2019

[0078] 2) Density ISO 534:2011

[0079] 3) WVTR ISO 2528, 23°C / 85% relative humidity

[0080] 4) Oxygen barrier properties ISO 15105-2, 23°C / 50% relative humidity

[0081] 5) Grease barrier performance ASTM F119-82, 40°C, using chicken fat

[0082] 6) Compostability and biodegradability EN 13432 or OECD 301

[0083] 7) Transparency DIN 53146

[0084] 8) Gulshan air permeability ISO 5636-5:2003

[0085] 9) Roughness ISO 2494

[0086] 10) Mineral Oil Barrier: Heptane Vapor Transmission Rate (HVTR) was determined gravimetrically, adapted from the method described in Gaudreault et al., 2013 (R. Gaudreault, C. Brochu, R. Sandrosck, P. Deglmann, H. Seyffer, and A. Tétreault, Overview of practical and theoretical aspects of mineral oil contaminants in mill process and paperboards, in Advances in Pulp and Paper. Research, Cambridge, 2013, Proceedings of the 15th Fund Translation, Research Symposium, Cambridge, 2013 (ed. S.J.I. Anson), pp. 907–925, FRC, Manchester, 2018, DOI: 10.15376 / frc.2013.2.907. A sponge was soaked in n-heptane in a test cup and then covered with test paper, barrier side down. The cup rim was then sealed with melted wax, and the filled and sealed cup was stored under standard conditions (50% relative humidity and 23°C). The cup was weighed immediately after sealing and then after 2, 3, 5, and 25 hours. The HVTR was determined according to the formula in Gaudreault et al. (2013).

[0087] 11) Adhesion to the paper substrate is determined on a scale of 0 to 5, with the higher the number, the better the adhesion. The polymer coating is introduced onto the substrate by extrusion and its adhesion to the paper surface is defined according to the criteria, which are classified as follows:

[0088] 1 = no adhesion, polymer layer peeling off;

[0089] 2 = poor adhesion, some fibers adhere to the peeled polymer layer;

[0090] 3 = Poor adhesion, less than 50% of the paper breaks in the coated area when the polymer layer is peeled off;

[0091] 4 = Moderate adhesion, more than 50% of the paperboard breaks in the coated area when the polymer layer is peeled off;

[0092] 5 = Perfect adhesion, when the polymer layer is peeled off the cardboard breaks across the entire coated area.

[0093] 12) Recycling tests are carried out according to PTS METHOD PTS-RH 021 / 97 (October 2012), which replaced the September 1997 version: "Testing of papermaking raw materials, pulps and additives - Identification of the recyclability of paper and paperboard packaging and graphic printing products".

[0094] For the purposes of this specification and claims, unless otherwise indicated, all ranges include any combination of the highest and lowest points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

[0095] Unless explicitly stated otherwise, the embodiments and examples described in the claims and the specification can be freely combined with each other.

[0096] In this specification, the term "include / comprising" can be used as an open term, but also includes the closed term "consisting of..." Therefore, unless otherwise specified, the word "include / comprising" can be understood as "including / comprising or consisting of..."

[0097] Unless otherwise stated, percentage values ​​relating to the amount of a material are percentages by weight (wt%). Unless otherwise stated, all percentage values ​​relating to the amount of a material refer to dry weight.

[0098] The term "WVTR" refers to water vapor transmission rate. Unless otherwise specified, the term "WVTR" refers to the water vapor barrier properties at a relative humidity of 85% and a temperature of 23°C.

[0099] In this application, unless otherwise stated, all contents (percentages) are based on dry weight.

[0100] The term "gsm" refers to grams per square meter (g / m 2 ). Unless otherwise stated, all weights are dry weights.

[0101] The term "RH" refers to the relative humidity of the air.

[0102] The terms "paper" and "base paper" refer to uncoated paper.

[0103] The term "support layer" refers to a coated paper comprising a first coating layer on a base paper.

[0104] Support layer

[0105] The support layer 1 comprises a base paper 2 and a first coating layer 3 .

[0106] The support layer and the base paper therein have a first side and a second side. Preferably, the first coating layer 3 is located on the first side of the base paper 2 .

[0107] The base paper 2 generally comprises cellulose-containing natural fibers as its main raw material, and may further comprise, for example, one or more fillers and / or additives.

[0108] The term "cellulose-containing natural fibers" refers to any plant material containing cellulose. Natural fibers may be derived from wood and / or may include other natural fibers in addition to wood-based natural fibers. Raw materials other than wood-based raw materials may also include agricultural waste, grasses, and / or other plant materials, such as straw, leaves, bark, seeds, legumes, flowers, stems, or fruits, which may be obtained from cotton, corn, wheat, oats, rye, barley, rice, flax, hemp, abaca, sisal, jute, ramie, kenaf, bagasse, bamboo, and / or reeds.

[0109] Preferably, the base paper 2 comprises cellulose-containing natural fibers derived from wood. The base paper 2 may include fibers from softwood trees, such as spruce, pine, fir, larch, Douglas fir, or hemlock, or fibers from hardwood trees, such as birch, aspen, poplar, alder, eucalyptus, or acacia, or a mixture of softwood and hardwood.

[0110] Preferably, the cellulose-containing natural fibers include chemically pulped natural fibers, i.e., pulp produced by a chemical pulping process. Thus, in a preferred embodiment, the content of chemically pulped natural fibers in the total cellulose-containing natural fibers used in the base paper product is at least 70%, at least 80%, or at least 90%, preferably at least 95% or 98%, by weight. Preferably, all cellulose-containing natural fibers used in the base paper are chemically pulped cellulose-containing natural fibers. Preferably, the base paper does not contain so-called mechanical pulp.

[0111] The base paper refers to an uncoated structure. As described above, the support layer 1 has a first coating layer 3 in addition to the base paper 2. Therefore, the base paper can be coated with the first coating layer 7 to obtain the support layer 1.

[0112] The support layer may have a first coating layer 3 on one or both sides of the base paper 2. Preferably, the support layer has a first coating layer 3 only on the first side of the paper. The second side of the paper may have a third coating layer 5.

[0113] Thus, preferably, the first coating layer 3 is located on a first side of the base paper 2 , while the third coating layer 5 , preferably consisting essentially of starch, is located on a second side of the base paper 2 .

[0114] The first coating layer 3 may comprise a single layer, or may be a multilayer structure comprising several layers, for example, two or three layers. Thus, in one embodiment, the first coating layer is composed of two or three layers. The technical effect is to further enhance the barrier properties, particularly the water vapor barrier properties.

[0115] Preferably, the first coating layer comprises only one layer on one side of the support layer, or comprises only one layer on both sides of the support layer. The technical effect is to simplify the process and reduce the manufacturing cost of the material.

[0116] In an advantageous embodiment, the paper has the first coating on one side only, preferably the paper has the third coating on the other side.The third coating 5 preferably comprises starch, more preferably at least essentially consists of starch.

[0117] In one embodiment, the oxygen barrier material has a third coating layer and, further, an additional coating layer on top of the third coating layer to improve the printability of the oxygen barrier material. The additional coating layer may contain, for example, 8-15% (by dry weight), preferably 10-13% (by dry weight), of a binder, and up to 89% (by dry weight) of a pigment. In this embodiment, the additional coating layer may have a grammage of, for example, 8-13 gsm.

[0118] The grammage of the first coating layer may be between 2 gsm and 10 gsm, preferably at least 3 gsm and less than 6 gsm. The technical effect is to provide a better surface so that full surface coverage can be achieved with a lower second coating weight.

[0119] Preferably, the first coating layer has a grammage of 3 to 10 gsm, more preferably 3.5 to 9 gsm, and most preferably 4 to 8.5 gsm. This technical effect is that it prepares the surface of the support layer 1 for subsequent coating and acts as an adhesion promoter for another coating. Another technical effect is that the first coating layer 3 and the second coating layer produce a synergistic effect, providing oxygen barrier properties to the oxygen barrier material 10.

[0120] The thickness of the first coating is preferably between 2 and 10 μm, more preferably between 3.5 and 9 μm, and most preferably between 4 and 8.5 μm. The technical effect is that oxygen protection is obtained economically and effectively by the second coating.

[0121] The first coating layer contains a binder.

[0122] The binder content of the first coating is at least 25% by weight (on a dry weight basis), preferably at least 32%, for example in the range of 35% to 60% (on a dry weight basis), most preferably 35% to 50% (on a dry weight basis), where the binder content is the relative proportion of the total content of the first coating.

[0123] The binder can be chosen from: dispersions of different polyesters, such as PLA, PBS, PBAT, PHA, PCL, copolymers (dipolymers) and terpolymers comprising or consisting of lactide, glycolide and caprolactone, starch, modified starch, enzymatically converted starch, polyvinyl alcohol, ethylene vinyl alcohol, modified cellulose and mixtures thereof.

[0124] Preferably, the first coating comprises a binder selected from the group consisting of polyvinyl alcohol, starch, modified starch, enzymatically converted starch, modified cellulose, biodegradable polyester, and mixtures thereof. The technical benefit of such a binder is that it achieves good oxygen barrier properties even when the paper is not high-density. Most preferably, the first coating comprises at least one of polyvinyl alcohol, modified starch, and enzymatically converted starch.

[0125] As mentioned above, the first coating layer may comprise one or two layers on one or both sides of the base paper, or consist of one or two layers on one or both sides of the base paper. Preferably, the first coating layer is only located on the first side of the base paper 2.

[0126] The first coating layer may include a layer containing a binder selected from the group consisting of polyvinyl alcohol, starch, modified starch, enzymatically converted starch, modified cellulose, biodegradable polyester, and mixtures thereof. The technical effect of such a material is to improve oxygen barrier properties even when the paper is not high-density paper. Most preferably, the first coating layer comprises at least one of polyvinyl alcohol, modified starch, and enzymatically converted starch.

[0127] Advantageously, the binder of the first coating layer comprises or consists of at least 60% by weight or at least 70% by weight, more advantageously at least 80% by weight or at least 90% by weight, and most advantageously at least 95% by weight of the aforementioned substances. The technical effect is to ensure that the first coating layer has good surface coverage and film-forming properties.

[0128] In one embodiment, the binder of the first coating comprises or consists of at least 60% or at least 70% by weight, more advantageously at least 80% or at least 90% by weight, and most advantageously at least 95% by weight of polyvinyl alcohol. A technical effect is to provide improved film formation for the first coating. Another technical effect is to provide improved surface energy levels.

[0129] Preferably, the binder of the first coating layer comprises a total amount of starch of at least 60% by weight or at least 70% by weight, more advantageously at least 80% by weight or at least 90% by weight, and most advantageously at least 95% by weight, determined by the total amount of modified starch and enzymatically converted starch. A technical effect is to provide a higher starch solids content. Another technical effect is to provide a cost-effective drying process for the first coating layer. Yet another technical effect is to provide an environmentally friendly coating with an increased biobased content.

[0130] In a preferred embodiment, the binder of the first coating layer comprises a mixture of PVA and modified starch, and / or enzymatically converted starch.

[0131] The first coating layer may further comprise a pigment. Mineral pigments may include, for example, at least one of kaolin, natural ground calcium carbonate, precipitated calcium carbonate, talc, calcium sulfate, and titanium dioxide. The pigment may include at least one flake pigment, such as clay.

[0132] The first coating layer may contain 30 to 75 wt% of mineral pigment, preferably 40 to 70 wt%, and more preferably 48 to 68 wt%, based on the total dry weight of the first coating layer. The use of mineral pigments can improve certain material properties and reduce product manufacturing costs. However, to achieve the desired barrier properties, the mineral content must be kept to a minimum.

[0133] Preferably, the primary pigment is clay or calcium carbonate, with clay being most preferred. The technical effect is better anchoring of the binder to the paper surface, reducing the likelihood of the binder penetrating into the micropores and macropores of the fiber network. Consequently, the binder is able to interact better with adjacent coatings applied to the paper substrate by extrusion coating.

[0134] The weight of the support layer 1 including the base paper 2 and the first coating layer 3 can be 35 to 110 g / m 2 , preferably 38 to 100 g / m 2 , more preferably 42 to 95 g / m 2 , more preferably 45 to 90 g / m 2 , most preferably 50 to 85 g / m 2 The technical result is a material with good strength properties. A thinner support layer with a lower grammage may result in reduced strength properties, but the significantly lighter material can reduce manufacturing and transportation costs and reduce the environmental burden.

[0135] The density of the support layer can be equal to or less than 1000 kg / m 3 , preferably at 800kg / m 3 Up to 990kg / m 3 In the range of 820 kg / m 3 Up to 970kg / m 3 More preferably, it is equal to or less than 950 kg / m 3 , for example at 850kg / m 3 Up to 950kg / m 3 More preferably, it is equal to or less than 940 kg / m 3 , more preferably equal to or less than 920 kg / m 3 , most preferably equal to or less than 900 kg / m 3 The technical effect is to provide an environmentally friendly product in which the energy consumption of the papermaking unit process (including the refining, dewatering and drying steps) is reduced.

[0136] The transparency of the support layer may be lower than 70%, preferably lower than 65%, more preferably lower than 60%, more preferably lower than 50%, and most preferably lower than 45%. The technical effect is that it has better dewatering performance, thereby saving energy in paper production.

[0137] The support layer may have a Gulshan air permeability in the range of 100 to 10,000 sec / 100 ml.

[0138] Preferably, the support layer has a Gulshan air permeability in the range of 100 sec / 100 ml to 3000 sec / 100 ml, more preferably equal to or less than 2500 sec / 100 ml, and most preferably equal to or less than 2000 sec / 100 ml. The technical effect is to provide an environmentally friendly product in which energy consumption in the papermaking unit process (including the refining, dewatering, and drying steps) is reduced. Surprisingly, oxygen barrier laminates can be produced even with support layers having such low Gulshan air permeabilities.

[0139] The roughness (Bendtsen) of the support layer, as determined according to ISO 2494, can be greater than 40 ml / min, for example, in the range of 60 ml / min to 120 ml / min. The technical effect is that by providing a support layer with such a roughness, the substrate to be coated with the second coating becomes smoother. The lower surface roughness provides a good substrate for the second coating application process.

[0140] The support layer does not need to provide a low water vapor transmission rate. In one embodiment, the support layer has a WVTR (23°C / 85% relative humidity, ISO 2528) of greater than 500 g / m 2 * days. Technical effects include improved simplicity of the manufacturing process, since the support layer (at least for itself) does not need to be provided with a water vapor barrier material. Furthermore, preferably, the mineral oil barrier of the support layer (HVTR method, heptane vapor transmission rate) is higher than 100 g / m 2 *sky.

[0141] The grease barrier (ASTM F119-82, 40°C, chicken fat) of the support layer may be less than 2 hours, or even less than 1 hour. Technical effects include improved ease of manufacturing, as the support layer (at least per se) does not need to provide a grease barrier material.

[0142] The oxygen barrier property (OTR, 23°C / 50% relative humidity, ISO 15105-2) of the support layer can be higher than 1000cc / m 2 *day, or even higher than 10,000cc / m 2*day. Technical effects include improved ease of manufacturing, as the support layer (at least in itself) does not need to provide oxygen barrier properties to the material. Another technical effect is the provision of an environmentally friendly material, as the support layer can use bio-based materials that do not have high oxygen barrier properties.

[0143] As described above, the first coating 3 is preferably located only on the first side of the base paper 2. In addition, one side of the oxygen barrier material (i.e., the second side of the base paper) may not include the first coating 3 or the second coating 4. In this embodiment, the third coating 5 may be applied to the second side of the base paper. The third coating 5 may be a surface sizing layer, such as a starch-based surface sizing layer. The third coating 5 may include enzymatically converted natural starch or other modified starch, such as dextrin or chemically modified starch. Therefore, at least one side (i.e., the first side) of the oxygen barrier material may have the first coating and the second coating, while the other side (i.e., the second side) may not be coated, or may include the third coating. Most preferably, the second side has the third coating 5 only on the base paper 2.

[0144] Preferably, the oxygen barrier material has a third coating on the second side of the paper, and the third coating comprises more than 60% starch by weight (on a dry weight basis), more preferably more than 80% starch by weight (on a dry weight basis), more preferably more than 90% starch by weight (on a dry weight basis), and most preferably at least 95% starch by weight (on a dry weight basis). Advantageously, the third coating has a grammage of 0.5-1.5 gsm, more preferably 0.7-1.3 gsm. Technical benefits of the third coating include: the starch on the second side aids in drying the coating, preventing blistering, dusting, sedimentation, and curling of the material. Further technical benefits include: reducing the porosity and improving the smoothness of the support layer, and reducing the tendency of fibers to shed during printing.

[0145] In an advantageous embodiment, the oxygen barrier material comprises:

[0146] - a first coating layer on the first side of the base paper, wherein the first coating layer comprises polyvinyl alcohol and a pigment (preferably kaolin); and

[0147] - a third coating layer on the second side of the base paper, wherein the third coating layer comprises starch, consists of starch or consists essentially of starch.

[0148] The technical effects of this combination include: the polyvinyl alcohol in the first coating composition improves the coating adhesion of subsequent coatings and enhances the barrier properties after barrier coating; while the starch on the second side helps the coating dry and prevents blistering, dusting, sedimentation and curling of the material.

[0149] In this advantageous embodiment, the coating composition of the first coating layer preferably comprises:

[0150] - polyvinyl alcohol in an amount equal to or greater than 30% by weight, more preferably equal to or greater than 40% by weight, for example 40-60% by weight, based on the total dry weight of the coating; and

[0151] - Pigments in a content equal to or greater than 30% by weight, more preferably equal to or greater than 40% by weight, based on the total dry weight of the coating.

[0152] Furthermore, preferably, the third coating is located on the second side of the base paper and comprises starch having a starch content equal to or greater than 60 wt%, more preferably equal to or greater than 80 wt%, based on the total dry weight of the coating on the second side of the paper.

[0153] The technical benefits of this combination include a controlled and efficient drying process and improved controllability of the oxygen barrier material's moisture distribution. Furthermore, this combination can improve the oxygen barrier material's printability, prevent dusting, and increase its surface strength. Further technical benefits include reduced porosity and a reduced tendency for fiber shedding during printing.

[0154] In one embodiment, the first coating layer is a multilayer structure comprising two or three layers. In this embodiment, the multilayer structure may include:

[0155] 1) a layer comprising PVA and a pigment (e.g. kaolin), and

[0156] 2) a layer comprising a binder and a pigment (e.g. kaolin) located on the previous layer, and

[0157] 3) An additional layer containing a binder and a pigment (eg, kaolin) located on the previous layer.

[0158] The multilayer structure of the first coating may include: a coating weight of 2 to 8 g / m 2 , preferably 5.0–6.5 g / m 2 A layer comprising at least one flake pigment and 20 to 60 wt % of polyvinyl alcohol (PVA), based on the total dry weight of the first coating; and a coating weight of 4 to 12 g / m 2 , preferably 6.0–10g / m 2 The further layer comprises at least one flake pigment and 20 to 60 wt % of a binder, based on the total dry weight of the layer.

[0159] However, preferably, the first coating consists of one coating layer.During experimental testing, it was found that additional test dispersion coating layers did not significantly improve the oxygen barrier properties of the oxygen barrier material.

[0160] Second coating

[0161] The support layer 1 comprises a base paper 2 and a first coating layer 3. The support layer 1 may be coated with a second coating layer 8 to obtain an oxygen barrier material 10 comprising the first coating layer 3 and the second coating layer 4.

[0162] Preferably, the first and second coating layers are located on the same side of the base paper 2. More preferably, the second coating layer is located above the first coating layer. More preferably, the second coating layer is located directly above the first coating layer. This results in a material with improved oxygen barrier properties. Alternatively, another coating layer, such as an adhesive layer 6, may be located between the first coating layer 3 and the second coating layer 4.

[0163] Advantageously, the second coating 4 comprises or consists of one or more biodegradable materials and partially or fully renewable raw materials, usually referred to as “biopolymers”.

[0164] The second coating may be based on a polymer. The second coating may be based on at least one of the following polymers and mixtures thereof:

[0165] - polybutylene succinate,

[0166] - polylactic acid, i.e. polylactide PLA, PLLA, PDLA, PDLLA and their copolymers (binary copolymers) and terpolymers,

[0167] -Polycaprolactone PCL,

[0168] -polyesteramide PEA,

[0169] -Polyhydroxyalkanoate PHA, namely PHB, PHBV, PH3B4B, PHBH,

[0170] - polybutyrate styrene PBS,

[0171] - Aliphatic aromatic copolyester AAC,

[0172] - starch-based starch-polymer blends, such as PSM and TPS, which advantageously contain at least 10% by weight and not more than 90% by weight of starch,

[0173] -polybutylene succinate terephthalate,

[0174] -polybutylene adipate terephthalate, and

[0175] -Other bio-polyesters.

[0176] The second coating may comprise a blend of the above polymers.

[0177] Preferably, the second coating is based on at least one of the following polymers and mixtures thereof:

[0178] - polybutylene succinate,

[0179] - polylactic acid, i.e. polylactide PLA, PLLA, PDLA, PDLLA and their copolymers (binary copolymers) and terpolymers,

[0180] -Polyhydroxyalkanoate PHA, namely PHB, PHBV, PH3B4B, PHBH,

[0181] - Aliphatic aromatic copolyester AAC,

[0182] - starch-based starch-polymer blends, such as PSM and TPS, which advantageously contain at least 10% by weight and not more than 90% by weight of starch, and

[0183] -Polybutylene adipate terephthalate.

[0184] More preferably, the second coating is based on at least one of the following polymers and mixtures thereof:

[0185] - polybutylene succinate,

[0186] - Polylactic acid, namely polylactide PLA, PLLA, PDLA, PDLLA,

[0187] - lactic acid copolymers (copolymers) and terpolymers, i.e. polylactide-co-glycolide (PLGA), polylactide-ε-caprolactone (PLCL) or polylactide-co-glycolide-ε-caprolactone (PLGCL),

[0188] - Polyhydroxyalkanoates PHA, namely PHB, PHBV, PH3B4, PHBH, and

[0189] -Polybutylene adipate terephthalate.

[0190] Preferably, the second coating layer comprises polybutylene succinate as its main polymer.The technical effect is to provide improved properties such as melting point and melt flow rate required for extrusion coating processes.

[0191] The second coating preferably has a grammage of 5 to 50 gsm, more preferably 8 to 35 gsm, and most preferably 12 to 25 gsm (based on dry weight). The technical effect is to improve the barrier properties of the oxygen barrier material in an economical and efficient manner.

[0192] The thickness of the second coating may be in the range of 4 to 40 μm, preferably 6 to 35 μm, more preferably 8 to 30 μm, most preferably 10 to 25 μm. The technical effect is that protection against oxygen is obtained economically and effectively by the second coating.

[0193] The second coating may also contain one or more additives, such as one or more slip additives, heat stabilizers, antiblocking agents or antistatic agents, and UV stabilizers, etc. The technical effect of the additives is to modify the surface and / or optical properties of the second coating.

[0194] In addition, the second coating layer may contain inert raw materials, which may be solid insoluble additives that provide, for example, opacity or color, such as talc, calcium carbonate, titanium dioxide, and / or carbon black. The content of the inert raw materials may be, for example, no greater than 10%, preferably less than 5%, and more preferably less than 2%. In a preferred embodiment, the second coating layer contains talc.

[0195] The second coating layer is separable from the oxygen barrier material. Preferably, the second coating layer is separable from the oxygen barrier material such that less than 5% by weight of the support layer remains with the second coating layer, and less than 5% by weight of the second coating layer remains with the support layer. Technical benefits include improved recyclability and / or compostability of the oxygen barrier material.

[0196] In order to determine the properties of the second coating, the second coating is preferably separated from the oxygen barrier material.

[0197] The separate second coating may have a thickness of less than 10 g / m 2 *Day mineral oil barrier properties (HVTR method, heptane vapor transmission rate). The technical effect is to improve the mineral oil barrier performance of the obtained oxygen barrier material.

[0198] The grease barrier property (ASTM F119-82, 40° C., chicken fat) of the separated second coating layer can be less than 36 hours or less than 30 hours. The technical effect is that the grease barrier property of the obtained oxygen barrier material is improved.

[0199] In one embodiment, the WVTR (23°C / 85% relative humidity, ISO 2528) value of the separated second coating is greater than 100 g / m 2 *sky.

[0200] The total amount of biopolymer in the second coating layer 4 can be at least 50% by weight, for example, 50 to 100% by weight, preferably 70 to 99.5% by weight, and more preferably 80 to 99% by weight, based on the total dry weight of the second coating layer. This has the technical effect of increasing the amount of biopolymer available to fill, for example, the interstices between pigment particles. Further technical effects include achieving enhanced oxygen barrier properties.

[0201] The total amount of recycled plastic (preferably biopolymer) in the second coating 4 may be 0 to 30 wt%, more preferably 2 to 20 wt%, calculated on the total dry weight of the second coating 4 .

[0202] The oxygen barrier property (OTR, 23℃ / 50% relative humidity) of the second coating can be higher than 100cc / m 2 *Day, preferably above 200cc / m 2 *day, or higher than 400cc / m 2 * days. Therefore, the second coating layer itself may not provide high oxygen barrier properties. Technical effects include improved ease of manufacturing because the second coating layer (at least on its own) does not need to provide oxygen barrier properties.

[0203] The second layer may comprise only one coating layer, or may comprise multiple coating layers. The second coating layer may constitute the outermost coating layer of the oxygen barrier material. However, for example, the second coating layer may have printing on it.

[0204] Adhesive layer

[0205] The oxygen barrier material may comprise an adhesive layer 6. The technical effect of the adhesive layer 6 is to bond the adjacent layers together and prevent delamination. The adhesion is preferably selected so that the second coating layer can have a tailored adhesion to the support layer that is sufficient for converting but enables separation (even manually) of the support layer and the second coating layer.

[0206] The bonding layer 6 may be selected such that it is compatible with adjacent coatings.

[0207] For example, some materials may be hydrophilic and lose their bonding strength when in contact with moisture. Suitable polymers for the adhesive layer preferably comprise or consist of highly polar polymers, for example based on maleic anhydride grafted polyolefins (e.g. PE or PP), ethylene-vinyl acetate copolymers (EVA), ethylene-acrylic acid copolymers (EAA), ethylene-butyl acrylate copolymers (EBA) or similar polyolefin copolymers, or polyurethanes.

[0208] The tie layer may be based on a non-reactive tie layer resin such as ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), or ethylene acrylic acid (EAA), or ethylene grafted maleic anhydride, or ethylene methacrylic acid (EMAA).

[0209] The adhesive layer may be based on a reactive adhesive layer resin, such as anhydride modified polyethylene (AMP). The technical effect is that the reactive adhesive layer resin can react with adjacent layers to form a strong bond between the layers.

[0210] The grammage of the adhesive layer may be, for example, 0.1 to 5 gsm, more preferably 0.5 to 3 gsm.

[0211] Preferably, the second coating is located directly on the first coating and the oxygen barrier material does not comprise a tie layer.

[0212] Furthermore, the oxygen barrier material advantageously does not include, for example, an EVOH-based layer. This has the technical effect of increasing the simplicity of the oxygen barrier material's manufacturing process and reducing manufacturing costs, as oxygen barrier properties can be achieved without an EVOH layer. Therefore, the oxygen barrier material is preferably EVOH-free. However, in one embodiment, the oxygen barrier material may also include an EVOH-based layer.

[0213] Oxygen barrier materials

[0214] As described above, the oxygen barrier material has a support layer and a second coating layer on the support layer. Preferably, the first coating layer and the second coating layer are located on the same side of the base paper, that is, on the first side of the base paper 2. In this case, the second coating layer is preferably located on top of the first coating layer.

[0215] The first coating and / or the second coating may also be located on both sides of the base paper.

[0216] Oxygen barrier materials may have:

[0217] - a support layer comprising paper and a first coating layer, having a WVTR value higher than 500 g / m 2 * days, and

[0218] - A second coating on a support layer having a WVTR value greater than 100 g / m 2 *day, for example, higher than 150g / m 2 *day, or higher than 200g / m 2 *sky,

[0219] Among them, the oxygen barrier material may have a density of less than 100 g / m 2 *Days, usually less than 80g / m 2 * Improved WVTR value (23°C / 85% relative humidity, ISO 2528) on the 10-day test. The technical effect is that, by using a support layer and / or a second coating layer with a significantly low WVTR value, an environmentally friendly material with a good WVTR value is provided.

[0220] Oxygen barrier materials may have:

[0221] - A support layer comprising paper and a first coating, typically having mineral oil barrier properties and an estimated heptane vapor transmission rate greater than 20 g / m 2 * days, and

[0222] - Second coating on the support layer, usually with a coating thickness higher than 2 g / m 2 *Day heptane vapor transmission rate,

[0223] Among them, the oxygen barrier material can have an improved mineral oil barrier property (HVTR method, heptane vapor transmission rate), less than 2g / m 2*day. The technical effect is to improve the mineral oil barrier properties of the resulting oxygen barrier material in a cost-effective manner. Another technical effect is to provide an environmentally friendly material, as bio-based materials that do not have high mineral oil barrier properties can be used for these layers.

[0224] Oxygen barrier materials may have:

[0225] - a support layer comprising paper and a first coating, typically having a grease barrier value of less than 2 hours, and

[0226] - a second coating on a support layer, typically having a grease barrier value of less than 36 hours,

[0227] The oxygen barrier material can achieve a grease barrier value exceeding 72 hours. This provides a cost-effective and efficient way to improve the grease barrier properties of the resulting oxygen barrier material. Another benefit is the provision of an environmentally friendly material, as these layers can utilize bio-based materials that do not exhibit high grease barrier properties.

[0228] The oxygen barrier value of the oxygen barrier material can be less than 80cc / m 2 *Day, preferably less than 50cc / m 2 *day, more preferably less than 30cc / m 2 * day, more preferably equal to or less than 20cc / m 2 *Day, most preferably equal to or less than 17cc / m 2 *sky.

[0229] Oxygen barrier materials may have:

[0230] - The oxygen barrier value of the support layer exceeds 500cc / m 2 *day, for example, more than 2000cc / m 2 * days, and

[0231] -The oxygen barrier value of the second coating itself exceeds 100cc / m 2 *Day, for example, more than 200cc / m 2 *sky,

[0232] The oxygen barrier value of the oxygen barrier material can be less than 80cc / m 2 *Daily, usually less than 50cc / m 2 *Day, preferably less than 30cc / m 2 * day, more preferably equal to or less than 20cc / m 2 *Day, most preferably equal to or less than 17cc / m 2 *day. The technical effect is to improve the barrier properties of oxygen barrier materials in a cost-effective manner. Another technical effect is to provide environmentally friendly materials because these layers can use materials that do not have high oxygen barrier properties.

[0233] The oxygen barrier material can be heat sealable. Heat sealability is measured at a sealing pressure of 0.6 bar using a dwell time of 1.0 second. In one embodiment, the second coating is heat sealable at least at 160°C (0.6 bar sealing pressure and 1.0 second dwell time). The second coating is also heat sealable at 140°C. Furthermore, the second coating is preferably heat sealable at 130°C. In a preferred embodiment, the second coating is heat sealable at least at a temperature of 120°C to 160°C. The technical benefit of heat sealability is to provide good sealing barrier properties in a cost-effective manner.

[0234] The adhesion between the support layer and the secondary coating is strong enough to allow the oxygen barrier material to be handled during converting. In experimental testing, the adhesion value was determined to be 1 (on a scale of 1-5). The oxygen barrier material was successfully tested in a vertical form-fill-seal (VFFS) packaging machine used to produce pillow-shaped pouches.

[0235] The second coating can be separated from the support layer by hand without leaving a significant amount of fibers or coating on the second coating. Preferably, the separated second layer contains less than 5% by weight of cellulose-based fibers and / or the first coating. This facilitates recycling, resulting in a higher recovery rate of the support layer and fiber fraction.

[0236] All the values ​​disclosed above regarding the oxygen barrier material refer to the values ​​of the oxygen barrier material consisting of the support layer and the second coating layer.

[0237] The value of the second coating layer can be determined based on separating the second coating layer from the oxygen barrier material.

[0238] The oxygen barrier material comprises at least a support layer and a second coating layer. In one embodiment, the oxygen barrier material 10 is composed of a base paper 2, a first coating layer and a second coating layer.

[0239] Laminate comprising at least two cellulosic fiber substrates

[0240] refer to Figure 2a -b and 3a-b, the support layer and the second coating layer may also be included in a structure comprising at least two cellulose fiber substrates (e.g. other paper and / or paperboard). In this embodiment, it is preferred to leave a layer of polymer-based coating between each adjacent cellulose fiber substrate.

[0241] The support layer and the second coating layer may also be included in at least one of the following laminate structures, as shown below:

[0242] ○ Support layer + second coating,

[0243] ○ Polymer-based coating + support layer + second coating,

[0244] ○Polymer-based coating + coated paperboard + polymer-based coating + support layer + second coating,

[0245] ○ Polymer-based coating + coated paperboard + polymer-based coating + adhesive layer + support layer + second coating,

[0246] ○ Polymer-based coating + coated paperboard + polymer-based coating + coated paper + polymer + support layer + second coating,

[0247] ○ Polymer-based coating + coated paper + polymer-based coating + support layer + second coating,

[0248] ○ Polymer-based coating + coated paper + polymer-based coating + support layer + second coating,

[0249] ○ Polymer-based coating + coated paper + polymer-based coating + adhesive layer + support layer + second coating,

[0250] ○ Polymer-based coating + coated paper + polymer-based coating + support layer + polymer-based coating + paper + second coating.

[0251] Each of the polymer-based coatings may have the same materials and / or properties as the second coating.

[0252] The coated papers may all have the same material and / or properties as the support layer.

[0253] The coating layer for coating paperboard and paper may have the same materials and / or properties as the first coating layer.

[0254] However, the barrier properties disclosed in this specification can be obtained by using only one support layer and one second coating layer.The laminate structure has at least the same barrier properties as the oxygen barrier material.

[0255] method

[0256] Figure 4 A simplified schematic diagram of the fabrication of oxygen barrier materials is shown.

[0257] A method for manufacturing an oxygen barrier material may include:

[0258] - provide a support layer, and

[0259] - Applying a second coating on one or both sides of the support layer by extrusion technology.

[0260] The support layer can be made from a papermaking machine. The base paper 2 is appropriately coated by a first coating unit 11 for applying a first coating layer 7. The first coating unit can be one of a knife coater, a dip roll coater, a nozzle unit, a short dwell unit, a rod coater, a spray gun coater, a film transfer coater, a curtain coating unit, or a spray unit.

[0261] Preferably, the first coating 7 is applied to the first side of the base paper 2 by using a size press, such as a size press or a film size press.

[0262] Preferably, the second side of the base paper is coated using a size press, such as a size press or a film size press.

[0263] Most preferably, a size press is used to simultaneously coat the first side of the base paper comprising the first coating layer and the second side of the base paper comprising the third coating layer (preferably a starch-based coating layer). Since the first coating layer and the starch-based coating layer can be applied using a single coating device, the technical effect is to improve production efficiency.

[0264] In an extrusion process, the second coating 8 is applied to the support layer 1 by means of an extruder 9. The extrusion coating may comprise or consist of a single type of polymer.

[0265] According to the prior art, the extruder 9 can be an extrusion device, a coextrusion device, an extrusion laminating device, or a coextrusion laminating device. During the extrusion process, a solid polymer is converted to a molten state under compression pressure. The purpose of extrusion is to form a thin film of molten material on the surface of the flowing material in a manner that is as uniform and controllable as possible. In the coextrusion process, the plastic layers are combined by multiple extrusion screws.

[0266] Thus, the second coating layer 8 comprising the biopolymer may be applied to the support layer using one of an extrusion technique, a coextrusion technique, an extrusion lamination technique, and a coextrusion lamination technique.

[0267] Experimental testing

[0268] Different support layers and secondary coatings as described in the specification were produced and tested.

[0269] Example 1

[0270] The support layer is coated with PBS extrusion coating with a coating weight of less than 30g / m 2BioPBS (BioPBS FZ79AC). This support layer is certified for compostability according to EN 13432. This PBS grade is certified "OK COMPOST in the EU by TUV Austria." This PBS grade does not possess any oxygen barrier properties. Furthermore, the support layer used does not possess any oxygen or mineral oil barrier properties.

[0271] Surprisingly, the oxygen barrier of the PBS extrusion coated laminate at 23°C / 50% relative humidity was about 14 cc / m 2 *The mineral oil barrier property measured by heptane vapor transmission rate (HVTR) is about 2g / m 2 *day, which can be considered an excellent value because it is less than 10g / m 2 *The HVTR value represents the high performance mineral oil barrier.

[0272] Surprisingly, materials with oxygen barrier properties can be produced even when using only a single extrusion coating polymer that does not have oxygen barrier properties.

[0273] Thanks to this new material, numerous advantages are achieved, such as adequate protection against oxygen. The new material can be used as part of protective packaging.

[0274] Comparative Example

[0275] Polyethylene is extrusion-coated onto kraft paper without an intermediate first coat. This is a typical structure for barrier materials used in packaging. The coating is non-biodegradable. Adhesion to uncoated base paper is rated 5 on a scale of 1 to 5, with 5 being the strongest.

[0276] It is not possible to manually peel the polyethylene layer from the paper ( Figure 5b ).

[0277] Example 2

[0278] The adhesion between the support layer and the second coating was tested.

[0279] Surprisingly, the film could be removed by hand without leaving behind significant amounts of fibers or coating. The adhesion value was determined to be 1 (on a scale of 1 to 5).

[0280] The adhesion of the second coating was still strong enough to handle the oxygen barrier material during the converting process. The oxygen barrier material was successfully tested in a vertical form-fill-seal (VFFS) packaging machine used to produce pillow-shaped pouches.

[0281]

[0282] Thus, the first coating layer containing the pigment has tailored adhesion properties that are advantageous for recycling, and the PBS layer can be separated from the support layer manually ( Figure 5a ).

[0283] Due to the low adhesion between the support layer and the second coating, a high recovery rate of the support layer and fiber parts can be achieved. In experimental tests, less than 5% of the support layer ended up as waste.

[0284] Example 3

[0285] The base paper according to this specification is dispersion coated using a water-based dispersion containing pigment and binder as follows:

[0286] A) A dispersion coating on base paper (material A, test point),

[0287] B) Two dispersion coatings on base paper (Material B, Comparative Example), and

[0288] C) Three dispersion coatings on base paper (Material C, Comparative Example).

[0289] All of these materials were further extrusion coated as described in Example 1.

[0290] Materials A, B, and C comprise a coating containing PVA and kaolin clay. The coating was applied using a size press.

[0291] Materials B and C also include another coating layer on top of the previous layer. The other coating layer includes latex and pigment. This coating layer is applied using a knife coater.

[0292] Material C also includes another coating layer on top of the previous layer. This other coating layer includes latex and pigment. This coating layer is applied using a knife coater.

[0293] For all materials A to C, the support layer comprises a first coating comprising 20 to 60 wt % polyvinyl alcohol (PVA), based on the total dry weight of the coating.

[0294] The coating weight of each additional layer of materials B and C was 6.0–10 g / m 2 , comprising at least one flake pigment and 20 to 60 wt. % of latex, based on the total dry weight of the layer.

[0295] During experimental testing, it was found that the additional dispersion coating did not significantly improve the oxygen barrier properties of the oxygen barrier material.

[0296] For example, for the tested materials, at 23°C / 50% relative humidity, the oxygen barrier properties of the materials were between 12 and 17 cc / m 2Therefore, for the oxygen barrier material described in Example 1, the additional dispersion coating containing the pigment and latex mixture did not provide a significant benefit in terms of oxygen barrier.

[0297] In addition, it is worth noting that the latex of materials B and C is not a biodegradable polymer material.

[0298] The invention can be modified within the scope of the appended claims.

Claims

1. A method for manufacturing an oxygen barrier material, comprising: - Provide density equal to or less than 1000kg / m 3 , preferably at 800kg / m 3 Up to 990kg / m 3 A support layer (1) therebetween, the support layer comprising: - paper (2) comprising cellulose-containing natural fibers, and - a first coating (3) on the paper (2), said first coating (3) comprising a binder, The first coating (3) has a gram weight of 2 g / m 2 Up to 10g / m 2 between, - Applying a second coating on the support layer (2) by extrusion technology, thereby forming a second coating layer (4) on the support layer (1), wherein the gram weight of the second coating layer is 5g / m 2 Up to 50g / m 2 between, in A) the second coating is compostable and / or biodegradable in an industrial compost, thereby being at least 90% biodegradable within 6 months, as determined according to standard EN 13432, and - the polymeric material in the first coating is biodegradable according to standard OECD 301, and - the oxygen barrier material (10) is compostable according to standard EN 13432, and B) The oxygen barrier value of the oxygen barrier material is less than 70cc / m 2 *Day, preferably less than 50cc / m 2 *day, more preferably less than 20cc / m 2 *Days, measured according to ISO 15105-2 at 23°C / 50% relative humidity.

2. An oxygen barrier material comprising: - a support layer (1) having a density equal to or less than 1000 kg / m 3 , preferably at 800kg / m 3 Up to 990kg / m 3 The support layer (1) comprises: - a paper (2) comprising cellulose-containing natural fibers, and - a first coating (3) on the paper (2), said first coating comprising a binder, The first coating (3) has a gram weight of 2 g / m 2 Up to 10g / m 2 between, and - a second coating layer (4) on the support layer (1), wherein the weight of the second coating layer (4) is 5 g / m 2 Up to 50g / m 2 between, in A) - the second coating (4) is compostable and / or biodegradable in industrial compost, thereby being at least 90% biodegradable within 6 months as determined in accordance with standard EN 13432, and - the polymeric material in the first coating is biodegradable according to standard OECD 301, and - the oxygen barrier material (10) is compostable according to standard EN 13432, and B) The oxygen barrier value of the oxygen barrier material (10) is less than 70cc / m 2 *Day, preferably less than 50cc / m 2 *day, more preferably less than 20cc / m 2 *Days, measured according to ISO 15105-2 at 23°C / 50% relative humidity.

3. A method or oxygen barrier material, wherein The first coating layer (3) and the second coating layer (4) are nanocellulose-free coating layers.

4. A method or oxygen barrier material, wherein The support layer has a density equal to or greater than 500 cc / m 2 *Day, preferably equal to or greater than 1000cc / m 2 *Day, most preferably greater than 5000cc / m 2 *Day-long oxygen barrier properties.

5. A method or oxygen barrier material, wherein The second coating has a thickness greater than 90 cc / m 2 *Day, preferably equal to or greater than 100cc / m 2 *Day, most preferably greater than 150cc / m 2 *Day-long oxygen barrier properties.

6. A method or oxygen barrier material, wherein The second coating (4) and the first coating (3) are located on a first side of the paper, and The second coating layer is located on the first coating layer.

7. The method or oxygen barrier material according to claim 6, wherein: The oxygen barrier material comprises a third coating (5) on the second side of the paper (2), the third coating comprising or consisting of starch.

8. The method or oxygen barrier material according to claim 7, wherein: The third coating layer (5) comprises equal to or greater than 80% by weight of starch, determined based on the total dry weight of the third coating layer (5).

9. The method or oxygen barrier material according to claim 7 or 8, wherein: The weight of the third coating is 0.5-1.5 g / m 2 , preferably 0.7-1.3g / m 2 .

10. A method or oxygen barrier material, wherein The second coating layer comprises at least one of polybutylene succinate, polyhydroxyalkanoate, a copolymer (dipolymer) or terpolymer of polylactic acid, glycolide and / or lactide, or polybutylene adipate terephthalate, Preferably, the second coating comprises polybutylene succinate.

11. A method or oxygen barrier material, wherein The first coating layer contains a binder selected from the group consisting of starch, modified starch, enzymatically converted starch, polyvinyl alcohol, modified cellulose, biodegradable polyester, and mixtures thereof, Preferably, the binder is selected from the group consisting of polyvinyl alcohol, starch, modified starch, enzymatically converted starch, modified cellulose and mixtures thereof.

12. A method or oxygen barrier material, wherein - The mineral oil barrier property (heptane vapor transmission rate) of the second coating is less than 10 g / m 2 * days, and / or - The mineral oil barrier property (heptane vapor transmission rate) of the support layer is at least 100 g / m 2 * days, and / or - The mineral oil barrier property (heptane vapor transmission rate) of the oxygen barrier material is less than 2g / m 2 *sky.

13. A method or oxygen barrier material, wherein - The WVTR value of the support layer is higher than 500g / m 2 * days, and / or - The WVTR value of the second coating is higher than 100g / m 2 * days, and / or - The WVTR value of oxygen barrier material is less than 100g / m 2 *sky, Measured according to ISO 2528 at 23°C / 85% relative humidity.

14. A method or oxygen barrier material, wherein - The grease barrier property of the support layer is less than 2 hours, and / or - The grease barrier of the second coating is less than 36 hours, and / or -Oxygen barrier material has a grease barrier property of more than 72 hours, Measured according to ASTM F119-82 at 40°C using chicken fat.

15. A method or oxygen barrier material, wherein The transparency of the support layer, measured according to standard DIN 53146, is less than 65%, preferably less than 50%.

16. A method or oxygen barrier material, wherein The Gulshan air permeability of the support layer is higher than 100 sec / 100 ml, preferably between 100 sec / 100 ml and 3000 sec / 100 ml.

17. A method or oxygen barrier material, wherein The second coating layer can be separated manually from the support layer.

18. A packaging material or package comprising the oxygen barrier material as claimed in any one of claims 2 to 17.

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