Not Applicable.
1. Field of the Invention
The invention relates to a compostable paper container with oxygen barrier properties.
2. Description of the Related Art
Typical coated paper containers have poor oxygen barrier properties and thus are poor for prepackaging of coffee and other food items that are oxygen sensitive for storage in warehouses, distribution and sales in stores.
A recent beverage industry trend for self brewing has been the development and acceptance of on-demand brewing of single servings through the use of coffee, tea and other beverages pre-packaged in single-use pods. The original pods are made from polypropylene (PP) with a barrier layer of ethyl vinyl alcohol (EVOH) with an aluminum foil or metallized plastic film lids. Several other variants have come on the market since. Unfortunately, polypropylene is not easily biodegradable and therefore, these pods are not compostable.
Therefore, what is needed are coated paper containers that are compostable and have good oxygen barrier properties.
The foregoing needs are met by compostable paper containers with oxygen barrier properties and methods of using the same as described herein.
In one aspect, the invention provides a container comprising a paper layer having oxygen barrier properties, wherein the container is compostable. The paper layer may be sized with an oxygen barrier chemical selected from polyvinyl alcohol, polyglycolic acid, and polytrimethylene terephthalate. The paper layer may be dry end sized with polyvinyl alcohol.
The container may further comprise an oxygen barrier layer. The oxygen barrier layer may comprise a compostable polymeric material selected from the group consisting of polylactic acid, polybutylene succinate, polybutylene adipate terephthalate, polybutylene adipate succinate, polyhydroxy alkanoate and blends thereof. The container may comprise an additional oxygen barrier layer comprising a metallized coating or a silicon dioxide coating.
The container may include a cup formed from the paper layer, and a bottom of the cup may be either flat or raised. A rim of the cup may be flanged or rolled. The rim may be rolled and flattened.
The container may be a component of a single-serve beverage pod for on-demand brewing. Preferably, the container is dimensioned to work in an on-demand single-serve brewing machine. The container may further comprise one or both of: (i) a compostable filter, and (ii) a compostable lid. Preferably, the container does not require disassembly after use in a brewing machine to be fully compostable. Preferably, the container has less than 3% oxygen content inside the container after one year, when initially flushed with nitrogen prior to sealing with a lid.
The container can include a cup formed from the paper layer, and a bottom wall of the cup can be pre-punctured, pre-scored, or have an iris. A bottom wall of the cup can include a hole covered by film or a peel off sticker.
In another aspect, the invention provides a method of producing a beverage with a single serve beverage dispensing machine comprising a container receiver arranged to receive a container. The method comprises using a compostable container comprising at least one component made from a coated paper with oxygen barrier properties. The method may comprise the steps of: (a) arranging the compostable container in the container receiver of the beverage dispensing machine; (b) introducing a liquid into the compostable container via a first opening in the compostable container; and (c) collecting the beverage from a fluid outlet of the compostable container.
These and other features, aspects, and advantages of the present invention will become better understood upon consideration of the following detailed description, drawings and appended claims.
Like reference numerals will be used to refer to like parts from Figure to Figure in the following description of the drawings.
A compostable paper container and methods of using the same are described herein. In a general embodiment, the compostable paper container has oxygen barrier properties. The paper container may be produced by any means including using a cup forming machine from companies such as those manufactured by Paper Machinery Corporation (PMC, Milwaukee, Wis.) or Michael Hörauf Maschinenfabrik (Donzdorf, Germany) which produce cups by cutting blanks from paper stock, then rolling the side wall and sealing a side seam, and then inserting a bottom and forming a bottom seal. Alternatively, the paper could be pressed into a form or mold to produce a container.
The paper container can be used to contain liquids or solids including, for example, coffee, soup, salad, sugar, whole and ground tea leaves, and whole and ground coffee beans. The paper container may be of any size, though the most suitable sizes are from 3 to 1000 milliliters in capacity. The single use or multiple use container may be sold as a food container, soup container, cup or pod and may be used to store prepackaged goods for warehousing and distribution to a store or consumer for in-store packing on demand or short sale for consumers to purchase.
The oxygen barrier properties of the paper layer or the container may be measured by any known means including using laboratory equipment for measuring oxygen transmission rate by companies such as Mocon International (Minneapolis, Minn.). Alternatively, the oxygen barrier properties may be determined by actual shelf life testing. One shelf life testing method is to fill a container with the product to be packaged for sale, nitrogen flush and then close the container; this container is then placed in actual storage conditions for the maximum storage time anticipated and then measuring the oxygen content of the atmosphere contained within the container or by determining the quality of the packaged product through taste or other testing.
The oxygen barrier properties of the container of the invention result in a reduced oxygen transmission rate versus typical paper coated with a 25 micron thick polyethylene coating and preferably a reduced oxygen transmission rate versus paper coated with a 25 micron thick polyethylene terephthalate (PET) coating.
The oxygen transmission rate (OTR) of the container can be expressed by many different complex units. One typical unit expression is cc·mil/(100 in2·day·atm). For this invention, the OTR is less than 2 cc·mil/(100 in2·day·atm), preferably less than 0.5 cc·mil/(100 in2·day·atm) and most preferably less than 0.3 cc·mil/(100 in2·day·atm).
The compostability of the paper structure and a container formed from the paper structure can be determined using standard test methods and specifications of ASTM, CEN, ISO or other accepted standards bodies. In general, compostability specifications require that a material or product pass four criteria: heavy metal content not to exceed 50% of that allowed for sewage sludge; 90% disintegration to less than 2 millimeter particles size in less than 84 days; 90% biodegradation as determined through carbon dioxide generation in less than 180 days; and non-toxicity to plants, and in some cases worms, as compared to a negative control. Preferably, the container passes ASTM D6400 or ASTM D6868 industrial compostability standards.
The paper layer of the compostable paper may be any typical unbleached, partially bleached or bleached paper produced from softwood, hardwood or a combination of the two. For containers, the typical paper stock in North America is standard bleached sulfate (SBS) paper. The bleaching may use by any known method including those using chlorine, peroxide, ozone and sodium hypochlorite. The paper layer may contain only virgin fiber or may include all or some recycled fiber. The paper layer may also contain any known chemicals for modifying the properties of paper.
The paper layer may be wet and/or dry end sized with a chemical to impart additional oxygen barrier properties using any method typically used in paper production. In one embodiment, a chemical that imparts additional oxygen barrier properties may be applied at the wet (internal sizing) or on the dry end (surface sizing), or both. These chemicals are typically also water soluble. Non-limiting example water soluble polymers include polyvinyl alcohol (PVOH), polyglycolic acid (PGA), and polytrimethylene terephthalate (PTT) though any fully or partially water soluble chemical that reduces the oxygen transmission rate is envisioned.
Polyvinyl alcohol, which is one of a few crystalline water soluble polymers, has excellent interfacial characteristics and mechanical characteristics, and is hence used for processing paper and fibers and stabilizing emulsions, and also as a starting material for polyvinyl alcohol film and polyvinyl alcohol fiber. Polyvinyl alcohols can have atactic, isotactic, heterotactic and syndiotactic stereospecificity. Changes in the stereospecificity of polyvinyl alcohol affect thermal resistance, crystallinity, melting point, the rate of water dissolvability and biodegradability. Polyvinyl alcohol comprises vinyl alcohol units and preferably consists essentially of vinyl alcohol units. There are no specific limitations with respect to the process for producing the polyvinyl alcohol used as a component in the diversion sand.
Polyvinyl alcohol may also be partially or fully functionalized to produce a polymer that is also water dissolvable. For example, PVOH may be reacted with acetic acid or an equivalent to produce polyvinyl acetate (PVA).
The paper layer may be coated with a compostable polymer including polylactic acid (PLA), polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), polybutylene adipate succinate (PBAS) and polyhydroxy alkanoates (PHA).
The compostable polymeric material described herein may be a thermoplastic that is produced from any combination of monomers or low molecular weight precursors that can produce a water dissolvable polymer. The polymers can be produced by any chemical means known such as a condensation reaction or a radical polymerization with and without catalysts in both instances. The thermoplastic polymer or combination of thermoplastic polymers may be among amorphous, semicrystalline or crystalline polymers. The polymeric materials may also be virgin, scrap, post-industrial recycled or post-consumer material.
The compostable polymeric material layer may also have been produced from a thermoset.
Polylactic acid (PLA) can be prepared according to any method known in the state of the art. For example, PLA can be prepared from lactic acid and/or from one or more of D-lactide (i.e. a dilactone, or a cyclic dimer of D-lactic acid), L-lactide (i.e. a dilactone, or a cyclic dimer of L-lactic acid), meso D,L-lactide (i.e. a cyclic dimer of D- and L-lactic acid), and racemic D,L-lactide (racemic D,L-lactide comprises a 1/1 mixture of D- and L-lactide).
Polylactic acid (PLA) can also be nucleated using mineral fillers or other polymers including highly stereospecific (e.g., >95% D) PLA polymers to dramatically increase the thermal resistance of PLA by having the material be semi-crystalline or crystalline rather than be amorphous.
The compostable polymeric material layer can be produced by any known means including blown and cast film extrusion and casting. The compostable polymeric material layer may also be unoriented, monoaxially or biaxially oriented.
The compostable polymeric material layer may also include any known additive for improving processability or properties of the polymeric material resins. Such additives include compatibilizers, especially if blending two or more polymers including impact modifiers, internal and external lubricants, thermal and UV stabilizers, flow promoters, polymer processing aids, slip agents, viscosity modifiers, chain extenders, nanoparticles, spherical glass beads, organic fillers, inorganic fillers, fibers, colorants, anti-microbial agents and the like. The additional components can be added to the polymer composition at any suitable time in the manufacturing process.
To reduce the oxygen transmission rate of the compostable polymeric material layer, the layer may also be further coated by any known method such as lamination, metallization or vapor deposition. The additional layer may be from a single to several atoms thick and may be comprised of aluminum or other metals or minerals such as silicon dioxide. It is preferred that this additional layer maintains the compostable properties of the polymeric material layer.
The polymeric material layer can be added to the paper layer through any known means including thermal and adhesive lamination and extrusion coating and metallization.
In adhesive lamination, an adhesive may be incorporated into or onto the polymeric material or paper layer during their manufacturing or may be applied between the two layers during the lamination process. Any known adhesive may be used including those that are sugar-based.
The compostable polymeric material layer with an additional oxygen barrier coating may be laminated to the paper layer with the oxygen barrier coating on the side facing the paper or away from the paper. Alternatively, a paper layer that is extrusion coated with the compostable polymeric material layer may be first metallized or otherwise coated before the compostable polymeric material is extruded onto the paper layer or the compostable polymeric material layer is extruded onto the paper layer and then is itself metallized or otherwise coated.
An alternative structure is to have the paper layer metallized or otherwise coated and not have a compostable polymeric material layer.
In the paper structures, the metallized coating would not be on the food contact surface if the metallized coating does not meet the local requirements and regulations for food packaging.
Containers formed from the compostable paper structure may include a container cup 60 (see
The containers formed from the compostable paper structure may have additional features for the product to function as needed. The container cup 60 may be covered with any film or paper lid 70 (see
The container cup 60 can house a filter 80 (see
Looking at the container 90 of
An interior section of the container cup bottom wall 61 may be flush with the bottom of the container cup 60 or be raised. In the embodiment of the cup 60a in
Having described construction of an example beverage dispensing machine, the making of a beverage can be described. First, a container 90 as in
Thus, the invention provides compostable paper containers with oxygen barrier properties and methods of using the same. The containers are suitable for use in on-demand brewing of single servings through the use of coffee, tea and other beverages pre-packaged in single-use pods comprising the compostable paper containers of the invention.
Although the invention has been described in detail with reference to certain embodiments, one skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which have been presented for purposes of illustration and not of limitation. Therefore, the scope of the appended claims should not be limited to the description of the embodiments contained herein.
This application claims priority to U.S. Patent Application No. 62/243,895 filed Oct. 20, 2015.
Number | Date | Country | |
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62243895 | Oct 2015 | US |