Aqueous barrier coatings and methods for improving barrier properties of packaging materials

Abstract

Aqueous paper barrier coatings and methods for improving the barrier properties of packaging materials including substrates with coatings that provide the packaging materials with controlled water vapor transmission, oxygen penetration or transmission, grease resistance, and optical properties are described.

Description

[Technical Field]

[0001] Aqueous barrier coatings and methods for improving the barrier properties of packaging materials are described, including coated substrates, to provide packaging materials with tailored water vapor transmission rates, oxygen permeability or transmission rates, oil and grease resistance, and optical properties. [Background technology]

[0002] The packaging material may be flexible packaging, which may be defined as a package or portion of a package that can be easily reshaped during filling or use. Flexible packaging is made from paper, plastic, film, aluminum foil, or a combination of these materials and includes bags, pouches, liners, wraps, roll stock, and other flexible products.

[0003] Flexible packaging is increasingly replacing traditional packaging, such as glass bottles and metal cans, every year as its advantages are recognized. These advantages include extended shelf life, increased cost efficiency, reduced packaging weight, and reduced transportation costs. However, most flexible packaging materials used today are plastics combined with aluminum foil. In light of the rising costs of both fossil fuel-based materials and aluminum, as well as their environmental impacts, the market needs to transition to more sustainable materials.

[0004] Paper-based packaging is increasingly being used in packaging food, medical, and cosmetic products due to its biodegradability, recyclability, and high percentage of bio-based content.

[0005] However, paper-based products require treatment or coating because uncoated paper provides a lower barrier to water (vapor), oxygen, and oils than other packaging materials, for example, for food, medicine, and cosmetics. This is problematic because these products can be quickly damaged or deteriorated by contact with water (vapor) and oxygen that penetrates the packaging. Another problem with untreated paper-based packaging is that if the contents are fatty, the fat will seep through the packaging to the outside. Moisture poses another problem for uncoated paper, as the uncoated paper absorbs it, softening and losing its structural strength.

[0006] A conventional solution to enhance the poor barrier performance of paper-based packaging is to apply a laminate to the surface of the substrate. Paper lamination typically involves coating the surface with an inert resin and curing it to form a rigid composite with the paper structure. However, there are many examples where laminated paper causes problems in typical commercial paper recycling systems, such as filter clogging in repulping systems, reduced fiber content in repulped paper, and reduced aesthetics and performance properties due to plastic contamination in the recycled paper.

[0007] Another method involves applying a plastic coating, such as a layer of polypropylene (PP) or polyethylene (PE), to the surface of the paper. This is done using a coating, printing, or laminating process. However, applying a plastic coating to paper is detrimental to the recyclability and biodegradability of paper-based materials due to the strong adhesion of the plastic to the paper fibers.

[0008] Another way to enhance the barrier performance of paper-based materials is to apply a water-based barrier coating to the paper surface. This formulation does not contain polymers, such as PP or PE, making the packaging more easily recyclable and less environmentally impactful. However, these types of coatings have been found to perform poorly compared to paper-based laminates.

[0009] Another technique for imparting barrier properties to paper is to treat the substrate with a polyvinyl alcohol solution. Typical polyvinyl alcohol solutions have high viscosity with low solids content. However, applying this product using a conventional paper coating machine is problematic due to the product's ease of flow at high paper machine speeds, its drying ability, and its higher price. Furthermore, although polyvinyl alcohol is biodegradable under optimal conditions, it is still a fossil fuel-based polymer product. Summary of the Invention [Problem to be solved by the invention]

[0010] There remains a strong need for water-based barrier coatings, or combinations thereof, with a maximum amount of non-fossil fuel content, to provide better barrier properties against water (vapor), oxygen, and / or oils in paper-based packaging. [Means for solving the problem]

[0011] A substrate, such as paper or fabric, having improved barrier properties is provided. The substrate has an outermost surface and an innermost surface disposed opposite each other. Disposed on and in direct contact with the outermost surface, the innermost surface, or both surfaces of the substrate are one or more optional primer coatings, followed by a biodegradable coating. The biodegradable coating can be disposed directly on the surface of the substrate or on the one or more optional primer coating layers. A hydrophobic, thermally adhesive topcoat layer is disposed on the biodegradable coating layer.

[0012] Also provided is a method for improving the barrier properties of a substrate, such as a paper or textile substrate. The method includes providing a substrate having an outermost and an innermost surface disposed opposite each other. An optional primer or first coating is applied to, and in direct contact with, the outermost, innermost, or both surfaces of the substrate to form a first coating layer on the substrate surface. This is followed by application of a biodegradable coating, either directly to the substrate or over the primer or first coating layer, if present. An additional polymer coating can be applied to the surface of the biodegradable coating layer prior to a final or topcoat layer. The topcoat or final coating layer can be applied to the surface of the biodegradable coating layer or any polymeric or outermost coating layer. The substrate can only have a topcoat layer following the biodegradable coating, or additional coatings can be disposed on the substrate before or after the biodegradable coating layer.

[0013] This Summary is provided for the purpose of introducing a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. DETAILED DESCRIPTION OF THE INVENTION

[0014] Substrates are provided that have a barrier coating that begins with at least two aqueous barrier coating layers, including a first biodegradable coating layer and a second hydrophobic topcoat layer. The coating layers are applied one on top of the other, each layer having a specific function. The substrate may also have a multi-layer structure, with one or more precoats or primer coatings applied before or after the biodegradable layer and / or topcoat layer. For example, the substrate may include a primer coating, including a highly pigmented barrier coating, followed by a second coating including a polyvinyl alcohol solution, and then a topcoat including a hydrophobic and / or thermally adhesive polymer coating. Surprisingly, it has been found that this configuration of coating layers provides unexpected results in terms of water vapor permeation barrier, oxygen permeation barrier, and grease barrier.

[0015] In some embodiments of the substrate, the substrate is a paper or textile product having two or more barrier coatings applied as layers to the substrate, thereby improving the barrier properties of the substrate.

[0016] Barrier coatings prevent the transmission of a variety of substances, including water, water vapor, oils, and grease, over a wide range of conditions and temperatures. The moisture vapor transmission rate (MVTR), also called the water vapor transmission rate (WVTR), is a measure of the amount of water vapor that passes through a substrate over a given period of time. There are many applications where moisture control is important.

[0017] The substrate has an outermost surface and an innermost surface disposed opposite each other. Disposed on one or both surfaces of the substrate and in direct contact therewith are an optional water-based primer coating, a biodegradable water-based coating disposed on the substrate or the optional primer coating, and then a water-based top coat. The top coat may be the outermost coating layer, or an additional coating may be disposed on the top coat layer.

[0018] In some embodiments, the substrate is a paper product having a top or outermost surface and an innermost or bottom surface. Optionally, one or more aqueous primer coatings are disposed on one or both surfaces of the substrate to form one or more coating layers on the substrate. A biodegradable aqueous coating is disposed on the surface of the substrate or on any primer coating layer. One or more additional polymer coatings can be optionally disposed on the biodegradable coating layer. A top coat is generally the outermost coating and is disposed on the surface of the biodegradable coating layer or any additional coating layer. However, an additional polymer coating can be disposed on the surface of the top coat, as long as the top coat layer is located outside the biodegradable coating layer.

[0019] In some embodiments, the substrate has one or more primer coatings disposed on and in contact with the outermost surface of the substrate, followed by a biodegradable coating, an optional additional polymer coating, and a top coat. Optionally, the additional polymer coating can be disposed on the top coat.

[0020] In some embodiments of the substrate, the primer coating is a water-based coating comprising one or more polymer emulsions and an inorganic pigment slurry. The polymer emulsion can be selected from styrene butadiene, styrene acrylate, polyethylene, polypropylene, polyethylene oxide, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinylamine, or a combination thereof. The inorganic pigment slurry can be selected from talc, kaolin, calcium carbonate, mica, montmorillonite, or a combination thereof.

[0021] In some embodiments, the primer coating has a polymer content of about 30% to about 70% by weight and a pigment content of about 30% to about 70% by weight, based on the total dry weight of the primer coating, or a polymer content of about 30% to 50% by weight and a pigment content of about 50% to 70% by weight, based on the total dry weight of the primer coating, or a polymer content of about 30% to 40% by weight and a pigment content of about 60% to 70% by weight, based on the total dry weight of the primer coating.

[0022] In some embodiments, the biodegradable coating is an aqueous coating comprising one or more biodegradable polymer emulsions, an inorganic pigment, and a plasticizer. The one or more biodegradable polymer emulsions can be selected from polyvinyl alcohol, polyethylene oxide, methylcellulose, cellulose acetate, sodium alginate, polyhydroxyalkanoates, polylactic acid, silk fibroin, soy protein, chitosan, thermoplastic starch, crosslinked starch, or a combination thereof. The inorganic pigment can be selected from talc, kaolin, calcium carbonate, mica, montmorillonite, or a combination thereof. The plasticizer can be selected from sugar alcohols, glycerol, propylene glycol, glyceryl triacetate, polymer polyols, urea, ethanol, isopropanol, or a combination thereof.

[0023] In another aspect, the biodegradable coating has a biodegradable polymer content of about 40% to 100% by weight, a pigment content of 0% to about 50% by weight, and a plasticizer content of 0% to about 20% by weight, based on the total dry weight of the biodegradable coating; or a biodegradable polymer content of about 50% to about 80% by weight, a pigment content of about 10% to about 40% by weight, and a plasticizer content of 0% to about 20% by weight, based on the total dry weight of the biodegradable coating; or a biodegradable polymer content of about 50% to about 70% by weight, a pigment content of about 25% to 35% by weight, and a plasticizer content of about 5% to about 15% by weight, based on the total dry weight of the biodegradable coating.

[0024] In some embodiments, the topcoat is a water-based coating comprising one or more polymeric emulsions and, optionally, one or more wax emulsions, wherein the polymer emulsion of the topcoat layer can be selected from styrene butadiene, styrene acrylate, polyethylene, polypropylene, polyethylene oxide, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinylamine, and combinations thereof, and the wax emulsion of the topcoat coating layer can be selected from paraffin, polyethylene, montan, palm, palm kernel, coconut, rapeseed, soybean, sunflower, castor, carnauba, beeswax, shellac, candelilla, sugarcane, rice bran, stearate, laurate, oleate, and combinations thereof.

[0025] In some embodiments, the top coat has a polymer content of about 50% to about 100% by weight and a wax content of about 0% to 50% by weight, based on the total dry weight of the top coat, or a polymer content of about 10% to about 90% by weight and a wax content of about 10% to 40% by weight, based on the total dry weight of the top coat, or a polymer content of about 70% to 80% by weight and a wax content of about 20% to 30% by weight, based on the total dry weight of the top coat.

[0026] In some embodiments, the coated substrate comprises a primer coating layer and a biodegradable coating layer, the primer coating layer being applied to the substrate at a rate of about 1 to about 50 grams per square meter (g / m 2 ), or approximately 5 g / m 2 to about 20 g / m 2 and the biodegradable coating layer can be disposed on the primer coating layer at a dry coating weight of about 1 to about 50 g / m. 2 , or about 5 g / m 2 to about 20 g / m 2 The dry coating mass may be:

[0027] In some embodiments, the topcoat layer has a coating weight of about 1 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 The dry coating mass is then applied.

[0028] In another embodiment, the substrate is paper or a textile and the coating is disposed on the innermost surface, the outermost surface, or both.

[0029] Additionally provided is a method for improving the barrier properties of a substrate, the method comprising the steps of providing a substrate having an outermost surface and an innermost surface disposed opposite each other, applying a biodegradable coating to the outermost surface, the innermost surface, or both of the substrate, and then applying a topcoat to the surface of the biodegradable coating.

[0030] In one aspect of the method, a first coating is applied over the paper substrate, which may be a primer coating or a biodegradable coating. This coating seals the surface of the paper and provides an additional water vapor barrier. A second or intermediate coating provides an oxygen barrier but must be shielded from water vapor. Due to the hydrophilic nature of the coating, excessive moisture absorption will result in a loss of oxygen barrier performance. A topcoat or third layer provides a water vapor barrier and thermal adhesion to seal the paper-based package.

[0031] In some embodiments of the method, one or more primer coating layers can be applied to the substrate, followed by a biodegradable coating, then one or more additional primer coating layers, then a topcoat.

[0032] In another embodiment of the method, an additional primer coating layer can be applied after the biodegradable coating layer and / or the topcoat layer.

[0033] In some embodiments of the method, any one or more primer coatings are aqueous coatings comprising one or more polymer emulsions and an inorganic pigment slurry, the polymer emulsions being selected from styrene butadiene, styrene acrylate, polyethylene, polypropylene, polyethylene oxide, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinylamine, or combinations thereof, and the inorganic pigment slurry being selected from talc, kaolin, calcium carbonate, mica, montmorillonite, or combinations thereof.

[0034] In yet another embodiment of the method, any one or more primer coatings can be applied before or after the biodegradable coating.

[0035] In some embodiments, the primer layer has a polymer content of about 30% to about 70% by weight and a pigment content of about 30% to about 70% by weight based on the total weight of the primer coating, or a polymer content of about 30% to about 50% by weight and a pigment content of about 50% to about 70% by weight based on the total weight of the primer coating, or a polymer content of about 30% to about 40% by weight and a pigment content of about 60% to about 70% by weight based on the total weight of the primer coating.

[0036] In some embodiments of the coated paper product, the biodegradable coating layer is an aqueous coating containing at least one biodegradable polymer emulsion, and optionally an inorganic pigment and a plasticizer. The biodegradable polymer emulsion is selected from polyvinyl alcohol, polyethylene oxide, methylcellulose, cellulose acetate, sodium alginate, polyhydroxyalkanoate, polylactic acid, silk fibroin, soy protein, chitosan, thermoplastic starch, crosslinked starch, or a combination thereof. The inorganic pigment can be selected from talc, kaolin, calcium carbonate, mica, montmorillonite, or a combination thereof. The plasticizer can be selected from sugar alcohols, glycerol, propylene glycol, glyceryl triacetate, polymer polyols, urea, ethanol, isopropanol, or a combination thereof.

[0037] In some embodiments, the biodegradable coating layer has a biodegradable polymer content of about 40% to about 100% by weight, a pigment content of 0% to about 50% by weight, and a plasticizer content of 0% to about 20% by weight, based on the total weight of the biodegradable coating; or a biodegradable polymer content of about 50% to about 80% by weight, a pigment content of about 10% to about 40% by weight, and a plasticizer content of 0% to about 20% by weight, based on the total weight of the biodegradable coating; or a biodegradable polymer content of about 50% to about 70% by weight, a pigment content of about 25% to about 35% by weight, and a plasticizer content of about 5% to about 15% by weight, based on the total weight of the biodegradable coating.

[0038] In some embodiments of the current method, the topcoat is an aqueous coating containing one or more polymer emulsions and, optionally, one or more wax emulsions. The composition of the aqueous coating for the topcoat layer has a polymer content of about 50% to about 100% by weight and a wax content of 0% to about 50% by weight, based on the total weight of the topcoat, or a polymer content of about 60% to about 90% by weight and a wax content of about 10% to about 40% by weight, based on the total weight of the topcoat, or a polymer content of about 70% to about 80% by weight and a wax content of about 20% to about 30% by weight, based on the total weight of the topcoat.

[0039] In some aspects of the current method, the polymer emulsion of the topcoat layer can be selected from styrene butadiene, styrene acrylate, polyethylene, polypropylene, polyethylene oxide, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinylamine, or a combination thereof, and the wax emulsion of the topcoat layer can be selected from paraffin, polyethylene, montan, palm, palm kernel, coconut, rapeseed, soybean, sunflower, castor, carnauba, beeswax, shellac, candelilla, sugarcane, rice bran, stearate, laurate, oleate, or a combination thereof.

[0040] In another embodiment of the method, the primer coat layer has a coating weight of about 1 gram per square meter (g / m 2 ) to approximately 50g / m 2 , or about 5 g / m 2 to about 20 g / m 2 can be applied at a dry coating weight of

[0041] In yet another embodiment of the method, the biodegradable coating layer has a mass of about 1 g / m 2 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 is applied at a dry coating weight of 1000 ppm.

[0042] In yet another aspect of the method, the topcoat coating layer is about 1 g / m 2 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 is applied at a dry coating weight of 1000 ppm. [Example]

[0043] As used herein, the term "water vapor transmission rate" or "WVTR" refers to the rate of water vapor passing through a film or substrate as measured according to the Water Vapor Transmission Test Method specified in the Test Methods section.

[0044] As used herein, the term "oxygen transmission rate" or "OTR" refers to the rate of water vapor passing through a film or substrate as measured according to the Oxygen Transmission Test Method specified in the Test Methods section.

[0045] Initially, research began by coating paper substrates with starch-based materials, which provided an excellent oil and grease (OGR) barrier in applications where thick coating layers or multiple layers could be applied. However, the desired outcome was to develop a coating that offered better or increased barrier protection than is currently available.

[0046] It was then decided to try a biowax-based coating on the substrate. This coating was applied by spray to molded fabric, where there was a high demand for an OGR barrier that maximized non-fossil fuel content. Spray application allowed for the application of thicker layers, thus making it possible to achieve comparisons with starch-based coatings.

[0047] The following detailed description is merely exemplary and is not intended to limit the invention or the application and uses of the invention. Unless otherwise specified or clear from the context, the term "about" as used herein is understood to mean within normal acceptance in the art. For example, within 2 standard deviations of the mean value. "About" can be understood to mean within 10%, 5%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% by weight of the stated value. Alternatively, "about" can be understood to mean the value exactly as stated. Unless otherwise clear from the context, all numerical values ​​provided herein are modified by the word "about."

[0048] The following study was conducted to provide a waterborne barrier coating system with fat, MOSH / MOAH, and water barrier properties equivalent to or better than fossil fuel-based barrier coatings. In this study, two layers of waterborne biowax coatings were applied to a paper substrate and heptane barrier tests were performed. Results showed that the barrier properties of the substrate were improved when a second waterborne biowax coating was placed on top of the first waterborne coating.

[0049] Based on these results, additional water-based, non-fossil fuel coatings were investigated. In particular, a biowax-based barrier coating was tested, which is plastic- and paraffin-free and derived from vegetable oils. Biowax barrier coatings also contain no harmful mineral oil saturated hydrocarbons (MOSH) or mineral oil aromatic hydrocarbons (MOAH).

[0050] Tests were conducted using multiple combinations of Topscreen® products (Solenis, LLC) to identify which of the various biowax-based products provided the best results in terms of barrier properties.

[0051] Studies were carried out on laboratory coated paper samples using a K Printing Proofer from RK Print Coat Instruments Ltd. with the following settings: V=220 / 240; Hz=50-60; A=2; Ph=1.

[0052] The first step was to calibrate the coater, then perform the actual coating and drying process. The final step involved measuring the coating weight of each sample using the formula and procedure described below.

[0053] Coater settings are displayed as CxVxMx, where C is the coater identification number, V is the speed setting on the coater's speed dial, and M is the groove size of the coating bar; the larger the number of coats on the bar, the more coatings will be applied. For example, C 3 V 4 M 6 Sheets coated at settings 0.01 were coated with coater 3 at a speed of 4 using a bar with groove 6. The coating machine settings used in each study are shown in the table below.

[0054] After the paper coater was calibrated according to standard operating guidelines, the paper substrate was coated according to the following procedure: 1) A blank sheet of paper was clamped on top of the coater. 2) A coating bar was used to pass it through the coater's retaining plate without applying pressure or removing any mass. The coating bar varies depending on the desired coating mass. 3) The paper sheet was coated, leaving the top half blank, which is necessary for measuring the coating mass. 4) The machine speed was adjusted to obtain the desired coating mass, as described below. 5) A thin layer of coating was spread on the surface of the paper parallel to the coating bar, and the bar was dragged across the surface of the paper. 6) The coated sheet was placed in an oven and dried at 120°C for 1 minute, or until dry.

[0055] The coating weight was measured on the coated paper as follows: After the coated paper was cooled, samples were obtained by cutting and weighing circles of a specified size from the white or uncoated paper and the coated paper. The coating weight can be calculated as follows: Coating mass = (mass of coated circle - mass of blank circle) x 168 Now, after the sample has been applied, the circle is re-weighed to determine the stabilized coating mass.

[0056] The following products were used in the following studies: TopScreen® DS 54T is a primer coating with a polyacrylate binder, TopScreen® RP 105 is a formulation with a styrene acrylate latex and biowax, TopScreen® HB 50A is a formulation with a polyacrylic acid binder and a low amount of biowax, and TopScreen® HB 21 is a formulation with a polyacrylic acid binder and a high amount of biowax.

[0057] Example 1 In this study, the penetration of polar substances is simulated using n-heptane. Test samples were prepared by cutting 86 mm diameter circles from the coated sheets. The moisture barrier of mineral oil is 1000 g / m 2 The paper was measured in units of 100 kJ / cm², and typical conditions for the climate chamber were either 23°C and 50% relative humidity (RH) or 25°C and 50% RH (T448 om-97). Under these conditions, the coated side of the paper was exposed to a glass jar containing 20 milliliters (ml) of n-heptane. A rubber gasket was then placed over the coated paper, and an open stopper (lid) was screwed onto the jar to create a climate-controlled environment. The paper was tested by weighing the jar and returning it to the climate-controlled environment every 24 hours for four days.

[0058] At the end of the four days, the total amount of n-heptane that had leached through the paper was measured in g / m2 Expressed in units of / day.

[0059] Two paper samples, designated Sample 1 and Sample 2, were tested in this study. Multiple coating combinations were tested, either as a single layer of coating or as a combination of a topcoat and primer coating. All coating combinations were tested on Sample 2 (Table 1a) and, depending on the results, on Sample 1 (Table 1b). For each sample, the coating layers and MOSH / MOAH measurements are shown in Tables 1a and 1b.

[0060] [Table 1]

[0061] Example 2 - WVTR / OTR Test After confirming the heptane test results of Example 1, the coatings were subjected to additional testing to measure WVTR and OTR. WVTR testing was performed using the gravity cup method according to ISO 2528 or ASTM E-96 standards at a temperature of 38°C and 90% relative humidity (RH). The test was performed manually using a deep test dish filled with 100g of dry silica gel in a controlled environment achieved in a climate chamber. Each sample was measured in duplicate, and the reported values ​​are rounded averages. Lower values ​​indicate less moisture transmission.

[0062] Oxygen transmission rate (OTR) measurements are performed according to international standards ISO 15105-2 (2003) or ASTM F 1927 (2014) at a test temperature of 23°C and 50% relative humidity for both the permeate and carrier gases. All samples are measured in duplicate and the values ​​shown are rounded averages. Lower values ​​indicate lower oxygen transmission.

[0063] The paper substrate was coated with a multi-layer system: a primer coating layer, an optional intermediate coating layer, and a topcoat layer. (登録商標)The product was tested as a primer coating and as a topcoat. (登録商標) For comparison with the formulation, a polyvinyl alcohol solution, TopSol (登録商標) 20, Biodegradable TopScreen (登録商標) Bio 4 (a formulation containing modified starch polymers, kaolin, and sorbitol) was used as the intermediate coating. (登録商標) DS 3V (a formulation containing styrene butadiene latex and high aspect ratio talc) with TopScreen as a primer or pre-coating (登録商標) Bio 4 and TopScreen (登録商標) Combined with DS 20I-F (a formulation containing styrene butadiene latex and paraffin wax); additional TopScreen (登録商標) The product, namely, TopScreen (登録商標) DS3V (a formulation containing styrene butadiene latex and high aspect ratio talc); TopScreen DS 54T (a primer coating containing a polyacrylate binder); TopScreen RP 105 (a formulation containing styrene acrylate latex and biowax); TopScreen HB 50A (a formulation containing a polyacrylic binder and a low amount of biowax); TopScreen HB 21 (a formulation containing a polyacrylic binder and a high amount of biowax); and TopScreen (登録商標) Formulations containing DS 34J (styrene acrylate binder and PEO (polyethylene oxide) wax) were tested as various coating layers.

[0064] Another objective of the formulation of the present invention is for the coating layer to achieve both excellent oxygen permeation barrier and oil and grease resistance. To achieve this, the coating must be hydrophilic in nature. Although there is a commonality between oxygen permeation barrier and oil and grease, it is not obvious that excellent fat resistance leads to excellent oxygen barrier performance.

[0065] Table 2 shows the TopScreen(登録商標) DS 3V was used as a primer coating, and polyvinyl alcohol (TopSol (登録商標) 20) were applied to various OTR barriers (TopSol (登録商標) 20) as the second layer.

[0066] [Table 2]

[0067] The result is a biodegradable coating called TopScreen (登録商標) Bio 4, TopSol (登録商標) When used in place of 20 in a multi-layer barrier coating approach, it not only offers advantages in terms of feasibility, drying performance, and bio-based content, but also exhibits superior barrier performance and is more economical than fossil fuel-based coatings.

[0068] Example 3 This example uses the same procedure as used in Example 2. This study was conducted to determine if the order of the coating layers affects the resulting barrier properties. Table 3 shows the order of the coating layers in the case of a polyvinyl alcohol layer on a Topscreen (登録商標) The results show that polyvinyl alcohol can be replaced and the barrier performance is comparable to that of Topscreen Bio 4. (登録商標) Bio 4 layers demonstrate improvement (using the same dry coating weight for each layer).

[0069] [Table 3]

[0070] Example 4 This study used the same procedure as described in Example 2. The study was conducted on two different paper substrates to determine whether the order of various coating layers, such as the primer coating, biodegradable coating, or top coating, affected the barrier properties. Therefore, the coating order was varied and MVTR and OTR tests were performed. The results are shown in Table 4.

[0071] [Table 4]

[0072] The results clearly show that when a topcoat layer comprising one or more polymer emulsions and one or more wax emulsions is placed on the surface of a biodegradable coating layer or on the surface of any polymer coating placed on the surface of a biodegradable coating, the barrier performance is improved.

[0073] While the foregoing detailed description of the inventive subject matter has presented at least one embodiment, it should be understood that numerous variations exist. It should also be noted that the foregoing embodiment is merely exemplary and is not intended to limit the scope, applicability, or configuration of the inventive subject matter in any way. Rather, the foregoing detailed description provides those skilled in the art with a convenient roadmap for implementing embodiments of the inventive subject matter. It will be understood that various modifications may be made. It will be understood that various changes may be made in the function and arrangement of elements described in the embodiments without departing from the scope of the inventive subject matter as set forth in the appended claims.

Claims

1. A substrate having improved barrier properties, comprising: a) a substrate having an outermost surface and an innermost surface disposed opposite one another; b) an optional primer coating layer disposed on and in direct contact with the outermost surface, the innermost surface, or both surfaces of the substrate; c) a biodegradable coating layer comprising at least one biodegradable polymer emulsion, the layer being disposed on and in direct contact with the outermost surface, the innermost surface, or both surfaces of the substrate, or any primer coating layer; d) optionally, one or more polymeric coatings disposed on the surface of the biodegradable coating layer; and e) a topcoat layer comprising one or more polymer emulsions and optionally one or more wax emulsions, disposed on the surface of the biodegradable coating layer or of any polymer coating disposed on the surface of the biodegradable coating; A substrate comprising:

2. 10. The substrate of claim 1, wherein the primer coating is present and comprises at least one polymer emulsion selected from styrene butadiene, styrene acrylate, polyethylene, polypropylene, polyethylene oxide, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinyl amine, and combinations thereof, and an inorganic pigment slurry selected from talc, kaolin, calcium carbonate, mica, montmorillonite, and combinations thereof.

3. 10. The substrate of claim 1, wherein the primer coating layer is present and has a polymer content of about 30% to about 70% by weight and an inorganic pigment content of 30% to 70% by weight, based on the total dry weight of the primer coating, or a polymer content of about 30% to about 50% by weight and an inorganic pigment content of about 50% to about 70% by weight, based on the total dry weight of the primer coating, or a polymer content of about 30% to about 40% by weight and an inorganic pigment content of about 60% to about 70% by weight, based on the total dry weight of the primer coating.

4. The primer coating is present and is about 1 g / m 2 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 10. The substrate of claim 1, wherein the coating is applied at a dry coating weight of

5. 10. The substrate of claim 1, wherein the at least one biodegradable polymer emulsion is selected from polyvinyl alcohol, polyethylene oxide, methylcellulose, cellulose acetate, sodium alginate, polyhydroxyalkanoate, polylactic acid, silk fibroin, soy protein, chitosan, thermoplastic starch, cross-linked starch, and combinations thereof.

6. 6. The biodegradable coating of claim 1, further comprising a plasticizer selected from a sugar alcohol, glycerol, propylene glycol, glyceryl triacetate, a polymeric polyol, urea, ethanol, isopropanol, and combinations thereof.

7. 6. The biodegradable coating of claim 1, further comprising an inorganic pigment selected from talc, kaolin, calcium carbonate, mica, montmorillonite, and combinations thereof.

8. 6. The substrate of claim 1, wherein the biodegradable coating layer has a polymer content of about 40% to about 100% by weight, an inorganic pigment content of 0% to about 50% by weight, and a plasticizer content of 0% to about 20% by weight, based on the total dry weight of the biodegradable coating; or a polymer content of about 50% to about 80% by weight, an inorganic pigment content of about 10% to about 40% by weight, and a plasticizer content of 0% to about 15% by weight, based on the total dry weight of the biodegradable coating; or a polymer content of about 50% to about 70% by weight, an inorganic pigment content of about 25% to about 35% by weight, and a plasticizer content of about 5% to about 15% by weight, based on the total dry weight of the biodegradable coating.

9. The biodegradable coating has a coating weight of about 1 g / m 2 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 6. The substrate of claim 1, wherein the coating is applied at a dry coating weight of

10. 6. The substrate of claim 1, wherein the one or more polymer emulsions of the topcoat layer are selected from styrene butadiene, styrene acrylate, polyethylene, polypropylene, polyethylene oxide, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinyl amine, and combinations thereof.

11. 6. The substrate of any one of claims 1 to 5, wherein the one or more wax emulsions of the topcoat layer are present and are selected from paraffin, polyethylene, montan, palm, palm kernel, coconut, rapeseed, soybean, sunflower, castor, carnauba, beeswax, shellac, candelilla, sugarcane, rice bran, stearates, laurates, oleates, and combinations thereof.

12. 6. The substrate of claim 1, wherein the topcoat layer has a polymer content of about 50% to about 100% by weight and a wax content of 0% to about 50% by weight, based on the total dry weight of the topcoat, or a polymer content of about 60% to about 90% by weight and a wax content of about 10% to about 40% by weight, based on the total dry weight of the topcoat, or a polymer content of about 70% to about 80% by weight and a wax content of about 20% to about 30% by weight, based on the total dry weight of the topcoat.

13. The top coat has a thickness of about 1 g / m 2 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 6. The substrate of claim 1, wherein the coating is applied at a dry coating weight of

14. The substrate according to any one of claims 1 to 5, wherein the substrate is paper or textile.

15. 1. A method for providing improved barrier properties of a substrate, comprising: a) providing a substrate having an outermost surface and an innermost surface disposed opposite one another; b) optionally applying a primer coating layer disposed on and in direct contact with the outermost surface, the innermost surface, or both surfaces of the substrate; c) applying a biodegradable coating layer comprising at least one biodegradable polymer emulsion disposed on and in direct contact with the outermost surface, the innermost surface, or both surfaces of the substrate, or any primer coating layer; d) optionally applying one or more polymeric coatings disposed on the surface of the biodegradable coating layer; and e) optionally applying a topcoat layer comprising one or more polymer emulsions and optionally one or more wax emulsions disposed on the surface of said biodegradable coating layer or of any polymer coating disposed on the surface of said biodegradable coating. A method comprising:

16. The primer coating has a thickness of about 1 g / m 2 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 16. The method of claim 15, wherein the coating is applied to the substrate at a dry coating weight of

17. 17. The method of claim 15 or 16, wherein the biodegradable coating further comprises a plasticizer and / or an inorganic pigment.

18. The biodegradable coating has a coating weight of about 1 g / m 2 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 17. The method of claim 15 or 16, wherein the coating is applied at a dry coating weight of

19. The top coat has a thickness of about 1 g / m 2 to about 50 g / m 2 , or about 5 g / m 2 to about 20 g / m 2 17. The method of claim 15 or 16, wherein the coating is applied at a dry coating weight of

20. 17. The method of claim 15 or 16, wherein the substrate is paper or textile.

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