OA20661A - Methods and apparatus for manufacturing fiber-based food containers. - Google Patents

Abstract

Methods and apparatus for manufacturing vacuum forming a produce container using a fiberbased slurry. The slurry includes a moisture barrier comprising alkylketene dimer in the range of about 4% by weight, and a cationic liquid starch component in the range of 1% - 7% by weight.

Description

METHODS AND APPARATUS FOR MANUFACTURING FIBERBASED FOOD CONTAINERS

INVENTORS:

YOKE Dou Chung

Brandon michael Moore

Yiyun Zhang

TECHNICAL FIELD

The présent invention relates, generally, to ecologically sustainable methods and apparatus for manufacturing containers and packaging materials and, more particularly, to the use of novel slurries for use in vacuum forming molded fïber products to replace plastics.

BACKGROUND

Pollution caused by single use plastic containers and packaging materials is épidémie, scarring the global landscape and threatening the health of ecosystems and the varions life forms that inhabit them. Trash cornes into contact with waterways and océans in the form of bits of Styrofoam and expanded polystyrène CEPS) packaging, to-go containers, bottles, thin film bags and photodegraded plastic pellets.

As this océan trash accumulâtes it forms massive patches of highly concentrated plastic islands located at each of our océans’ gyres. Sunlight and waves cause floating plastics to break into increasingly smaller particles, but they never completely disappear or biodegrade. A single plastic microbead can be one million times more toxic than the water around it. Plastic particles act as sponges for l

waterborne contaminants such as pesticides. Fish, turtles and even whales eat plastic objects, which can sicken or kill them. Smaller océan animais ingest tiny plastic particles and pass them on to us when we eat seafood.

Sustainable solutions for reducing plastic pollution are gaining momentum. However, continuing adoption requires these solutions to not only be good for the environment, but also compétitive wîth plastics from both a performance and a cost standpoint. The présent invention involves replacing plastics with revolutionary technologies in molded fiber without compromising product performance, within a compétitive cost structure.

By way of brief background, molded paper pulp Cmolded fiber) has been used since the 1930s to make containers, trays and other packages, but experienced a décliné in the 1970s after the introduction of plastic foam packaging. Paper pulp can be produced from old newsprint, corrugated boxes and other plant fibers. Today, molded pulp packaging is widely used for electronics, household goods, automotive parts and medical products, and as an edge/corner protector or pallet tray for shipping electronic and other fragile components. Molds are made by machining a métal tool in the shape of a mirror image of the finished package. Holes are drilled through the tool and then a screen is attached to its surface. The vacuum is drawn through the holes while the screen prevents the pulp from clogging the holes.

The two most common types of molded pulp are classified as Type 1 and Type 2. Type 1 is commonly used for support packaging applications with 3/16 inch (4.7 mm) to 1/2 inch (12.7 mm) walls. Type 1 molded pulp manufacturing, also known as “dry” manufacturing, uses a fiber slurry made from ground newsprint, kraft paper or other fibers dissolved in water. A mold mounted on a platen is dipped or submerged in the slurry and a vacuum is applied to the generally convex backside.

The vacuum pulls the slurry onto the mold to form the shape of the package. While still under the vacuum, the mold is removed from the slurry tank, allowing the water to drain from the pulp. Air is then blown through the tool to eject the molded fiber piece. The part is typically deposited on a conveyor that moves through a drying oven.

Type 2 molded pulp manufacturing, also known as “wet” manufacturing, is typically used for packaging electronic equipment, cellular phones and household items with containers that hâve 0.02 inch (0.5 mm) to .06 in ch ¢1.5 mm) walls. Type 2 molded pulp uses the same material and follows the same basic process as Type 1 manufacturing up the point where the vacuum pulls the slurry onto the mold. After this step, a transfer mold mates with the fiber package, moves the formed “wet part” to a hot press, and compresses and dries the fiber material to increase density and provide a smooth external surface finish. See, for example, http: / / v\ww. stratasvs.com/solutions/additi ve-manufacturing/tooling/molded--fiber ; http://www.keiding.com/molded~fiber/Tnanufacturing-process/; Grenidea

Technologies PTE Ltd. European Patent Publication Number EP 1492926 Bi published April 11, 2007 and entitled “Improved Molded Fiber Manufacturing”; and http://afpackaging.com/thermoformed-fiber-molded-pulp/. The entire contents of ail of the foregoing are hereby incorporated by this reference.

Fiber-based packaging products are biodégradable, compostable and, unlike plastics, do not migrate into the océan. However, presently known fiber technologies are not well suited for use with méat and poultry containers, prepared food, produce, microwavable food containers, and lids for beverage containers such as hot coffee.

Methods and apparatus are thus needed which overcome the limitations of the prior art.

Various features and characterîstics will also become apparent from the subséquent detailed description and the appended daims, taken in conjunction with the accompanying drawings and this background section.

BRIE F SUMMARY

Various embodiments of the présent invention relate to methods, Chemical formulae, and apparatus for manufacturing vacuum molded, fiber-based packaging and container products including, inter alia: i) méat, produce, horticulture, and utility containers embodying novel géométrie features which promote structural rigîdity; ii) méat, produce, horticulture containers having embedded and/or topical moisture/vapor barriers; iii) vacuum tooling modified to re-direct spray nozzles to increase the size of vent holes in produce and horticulture containers; iv) microwavable/oven-heated containers embodying embedded and/or topical moisture, oil, and/or vapor barriers, and/or rétention aids to improve Chemical bonding; v) méat containers embodying a moisture/vapor barrier which préserves structural rigîdity over an extended shelf life; vi) lids for hot beverage containers embodying a moisture/vapor barrier; and vii) vacuum tooling modified to include a piston for ejecting beverage lids having a négative draft from the mold.

It should be noted that the various inventions described herein, while illustrated in the context of coiwentional slurry-based vacuum form processes, are not so limited. Those skilled in the art will appreciate that the inventions described herein may contemplate any fiber-based manufacturing modality, including 3D printing techniques.

Various other embodiments, aspects, and features are described in greater detail below.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Exemplary embodiments will hereinafter be described in conjunction with the appended drawing figures, wherein like numerals dénoté like éléments, and:

FIG. 1 is a schematic block diagram of an exemplary vacuum forming process using a fïber-based sium in accordance with varions embodiments;

FIG. 2 is a schematic block diagram of an exemplary closed loop slurry System for controlling the Chemical composition of the slurry in accordance with varions embodiments;

FIG. 3 is a perspective view of an exemplary produce container depicting a rolled edge, overhanging skirt, and ribbed structural features for enhancing hoop strength in accordance with varions embodiments;

FIG. 4 is an end view of the container shown in FIG. 3 in accordance with varions embodiments;

FIG. 5A is a perspective view of an exemplary produce container including extended vent holes in accordance with varions embodiments;

FIG. 5B is an end view of the container shown in FIG. 5A in accordance with varions embodiments;

FIGS. 6A - 6C are alternate embodiments of food containers îllustrating varions shelf and rib features in accordance with varions embodiments;

FIG. 7 is a perspective view of an exemplary rinsing tool including spray nozzles configured to rinse pulp from vent hole inserts in accordance with varions embodiments;

FIG. 8 is a close up view of the spray nozzles shown in FIG. 7 in accordance with varions embodiments;

FIG. 9 is a perspective view of the excess fiber targeted for removal by the spray nozzles shown in FIGS. 7 and 8 in accordance with varions embodiments;

FIG. ίο is a perspective view of an exemplary microwavable food container in accordance with varions embodiments;

FIG. 11A is a perspective view of an exemplary méat container in accordance with varions embodiments;

FIG. 11B is an end view of the microwavable food container shown in FIG. 11A in accordance with varions embodiments;

FIG. 12 is an alternative embodiment of a shallow food tray illnstrating a shelf having off-set ribs in accordance with varions embodiments;

FIG. 13 is a perspective view of an exemplary lid for a liquid (e.g., soup or a beverage such as coffee or soda) container in accordance with varions embodiments;

FIG. 14 is a top view of the lid shown in FIG. 13 in accordance with varions embodiments;

FIG. 15 is a side élévation view of the lid shown in FIGS. 13 and 14 in accordance with varions embodiments;

FIG. 16 is a perspective view of an exemplary mold for use in manufacturing the lid shown in FIGS. 13 -15 in accordance with varions embodiments;

FIG. 17 is a side élévation view^r of the mold of FIG. 16 shown in the retracted position in accordance with varions embodiments;

FIG. 18 is a side élévation view of mold of FIG. 17 showm in the extended position in accordance with varions embodiments; and

FIG 19 is a perspective view^r of utility (non-food) container in accordance with varions embodiments.

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

Varions embodiments of the présent invention relate to fiber-based or pulpbase products for use both within and outside of the food and beverage industry. By way of non-limiting example, the présent disclosure relates to particular Chemical formulations of slurries adapted to address the unique challenges facing the food industry including oil barriers, moisture barriers, and water vapor barriers, and rétention aids, the absence of which hâve heretofore prevented fiber-based products from dîsplacing single use plastic containers and components in the food industry. The présent disclosure further contemplâtes fiber-based containers having géométrie and structural features for enhanced rigidity. Coupling these features with novel chemistries enables fiber-based products to replace their plastic counterparts in a wide variety of applications such as, for example: frozen, refrigerated, and nonrefrigerated foods; medical, pharmaceutical, and biological applications; microwavable food containers; beverages; comestible and non-comestible liquids; substances which liberate water, oil, and/or water vapor during storage, shipment, and préparation (e.g., cooking); horticultural applications including consumable and landscaping/gardening plants, flowers, herbs, shrubs, and trees; Chemical storage and dispensing apparatus (e.g., paint trays); produce (including human and animal foodstuffs such as fruits and vegetables); salads; prepared foods; packaging for méat, poultry, and fish; lids; cups; bottles; guides and separators for processing and displaying the foregoing; edge and corner pièces for packing, storing, and shipping 7 electronics, mirrors, fine art, and other fragile components; buckets; tubes; industrial, automotive, marine, aerospace and military components such as gaskets, spacers, seals, cushions, and the like; and associated molds, wire mesh forms, recipes, processes, Chemical formulae, tooling, slurry distribution, Chemical monitoring, Chemical infusion, and related Systems, apparatus, methods, and techniques for manufacturing the foregoîng components.

Referring now to FIG. i, an exemplary vacuum forming System and process 100 using a fiber-based slurry includes a fîrst stage loi in which mold (not shown for clarity) in the form of a mirror image of the product to be manufactured is envelop in a thin wire mesh form 102 to match the contour of the mold. A supply 104 of a fiber-based slurry 104 is input at a pressure (Pi) 106 (typically ambient pressure). By maintaining a lower pressure (P2) 108 inside the mold, the slurry is drawn through the mesh form, trapping fiber particles in the shape of the mold, while evacuating excess slurry 110 for recirculation back into the System.

With continued reference to FIG. 1, a second stage 103 involves accumulating a fiber layer 130 around the wire mesh in the shape of the mold. When the layer 130 reaches a desired thickness, the mold enters a thîrd stage 105 for either wet or dry curing. In a wet curing process, the formed part is transferred to a heated press Cnot shown) and the layer 130 is compressed and dried to a desired thickness, thereby yielding a smooth external surface finish for the finished part. In a dry curing process, heated air is passed directly over the layer 130 to remove moisture therefrom, resulting in a more textured finish much like a conventional egg carton.

In accordance with varions embodiments the vacuum mold process is operated as a closed loop System, in that the unused slurry is re-circulated back into the bath where the product is formed. As such, some of the Chemical additives (discussed in more detail below) are absorbed into the individual fibers, and some of 8 the additive remains in the water-based solution. During vacuum formation, only the fîbers (which hâve absorbed some of the additives) are trapped into the form, while the remaining additives are re-circulated back into the tank. Consequently, only the additives captured in the formed part must be replenished, as the remaining additives are re-circulated with the slurry in solution. As described below, the System maintains a steady State chemistry within the vacuum tank at predetermined volumétrie ratios of the constituent components comprising the slurry’.

Referring now to FIG. 2, is a closed loop slurry System 200 for controlling the chemical composition of the slurry. In the illustrated embodiment a tank 202 is filled with a fiber-based slurry 204 having a particular desired chemistry, whereupon a vacuum mold 206 is immersed into the slurry bath to form a molded part. After the molded part is formed to a desired thickness, the mold 206 is removed for subséquent processing 208 (e.g., forming, heating, diying, top coating, and the like).

In a typical wet press process, the Hot Press Température Range is around 150-250 degree C, wiLh a Hot Press Pressure Range around i4O-i7okg/cm². The final product density should be around 0.5-1.5 g/cm3, and most likely around o.9-1.1 g/cm3. Final product thickness is about 0.3-1.5mm, and preferably about 0.50.8mm.

With continued reference to FIG. 2, a fiber-based slurry comprising pulp and water is input into the tank 202 at a slurry input 210. In various embodiments, a grinder may be used to grind the pulp fiber to create additional bonding sites. One or more additional components or chemical additives may be supplied at respective inputs 212 - 214. The slurry may be re-circulated using a closed loop conduit 218, adding additional pulp and/or water as needed. To maintain a steady State balance of the desired chemical additives, a sampling module 9

216 is configurée! to measure or otherwise monitor the constituent components of the slurry, and dynamically or periodically adjust the respective additive levels by controlling respective inputs 212 - 214. Typically the slurry concentration is around 0.1-1%, most ideally around 0.3-0.4%. In one embodiment, the varions Chemical constituents are maintained at a predetermined desired percent by volume; alternatively, the chemistry may be maintained based on percent by weight or any other desired control modality.

The pulp fiber used in 202 can also be mechanically grinded to improve fiber-to-fiber bonding and improve bonding of Chemicals to the fiber. In this way the slurry undergoes a refining process which changes the freeness, or drainage rate, of fiber materials. Refining physically modifies fibers to fibrillate and make them more flexible to achieve better bonding. Also, the refining process can increases tensile and burst strength of the final product. Freeness, in varions embodiments, is related to the surface conditions and swelling of the fibers. Freeness (csf) is suitably within the range of 200-700, and preferably about 220-250 for many of the processes and products described herein.

The chemical formulae (sometimes referred to herein as “chemistries”) and product configurations for various fîber-based packages and containers, as well as their methods for manufacture, will now be described in conjunction with FIGS. 3 - 19.

PRODUCE CONTAINERS

FIG. 3 is a perspective view of an exemplary produce container (e.g., mushroom till) 300 depicting a rolled edge 302, overhanging skirt 304, and various structural features including side panels exhibiting an outward bow, side ribs 306 and bottom ribs 308 for enhancing hoop strength. In this context, the term 10 hoop strength refers to a measure of the applied latéral force along opposing vectors 310 versus the resulting deflection. Although the initial hoop strength of a container is primarily a function of geo metry, hoop strength tends to dégradé as the container absorbs moisture leached from its contents (e.g., mushrooms). The présent inventor has determined that coupling various géométrie features with slurry chemistries optimized for various applications can sustain hoop strength over extended shelf times. That is, by incorporating a moisture repellant barrier into the slurry (and/or applying a moisture repellant surface coating), the hoop strength may be maintained for a longer period of time even as the container contents bleed moisture.

FIG. 4 is an end view of a container 400 generally analogous to the container shown in FIG. 3, and illustrâtes a width dimension 402, a height dimension 404, and a skirt length 408 in the range of .1 to 5 millimeters, and preferably about 1.5 mm. in the illustrated embodiment, the skirt extends downwardly; alternatively, the skirt may extend at an oblique or obtuse angle relative to a vertical plane. Width and height dimensions 402, 404 may be any désired values, for example in the range of 20 to 400 mm, and preferably about 60 to 200 mm.

As briefly mentioned above, the various slurries used to vacuum mold containers according to the présent invention comprises a fiber base mixture of pulp and water, with added Chemical components to impart desired performance characteristics tuned to each particular product application. The base fiber may include any one or combination of at least the following materials: softwood (SW), bagasse, bamboo, old corrugated containers (OCC), and newsprint (NP). Alternatively, the base fiber may be selected in accordance with the following resources, the entire contents of which are hereby incorporated by this reference: “Lignocellulosic Fibers and Wood Handbook: Renewable Materials for Today's 11

Environment,” edited by Mohamed Naceur Belgacem and Antonio Pizzi (Copyright 2016 by Scrivener Publishing, LLC) and available at https://books.google.com/books?id=jTL8CwAAOBAJ&printsec=frontcover#v=onep age&q&f-false: “Efficient Use of Flourescent Whitening Agents and Shading Colorants in the Production of White Paper and Board” by Liisa Ohlsson and Robert Federe, Published October 8, 2002 in the African Pulp and Paper Week and available at http://www.tappsa.c0.za/archive/APPW2002/Title/Eff1cient use of fluorescent w/effïcient use of fluorescent w.html; Cellulosic Pulps, Fibres and Materials: Cellucon '98 Proceedings, edited by J F Kennedy, G O Phillips, P A Williams, copyright 20 O by Woodhead Publishing Ltd. and available at https://books.google.com/books?id=xO2iAgAAOBAJ&printsec=frontœrver#v=onep age&q&f-false; and U.S. Patent No. 5,169,497 A entitled “Application of Enzymes and Flocculants for Enhancing the Freeness of Paper Making Pulp” issued December 8,1992.

For vacuum molded produce containers manufactured using either a wet or dry press, a fiber base of OCC and NP may be used, where the OCC component is between 50% - 100%, and preferably about 70% OCC and 30% NP, with an added moisture/water repellant in the range of 1% - 10% by weight, and preferably about 1.5% - 4%, and most preferably about 4%. In a preferred embodiment, the moisture/water barrier may comprise alkylketene dimer (AKD) (for example, AKD 80) and/or long chain diketenes, available from FOBCHEM at http://www.fobchem.com/html products/Alkyl-Ketene-Dimer%EF%BC%88AKDWAX%EF%BC%89.html#.VozozvkrKUk; and Yanzhou Tiancheng Chemical Co., Ltd. at httpi//www₁yztianchengçhenLçom/enZindex_iphp?m^çontent&ç^i^^ tid=38&id=i24&gclid=CPbn65aUg8oCFRCOaOodoJUGRg.

In order to yield spécifie colors for molded pulp products, cationic dye or liber reactive dye may be added to the pulp. Fiber reactive dyes, such as Procion MX, bond with the fiber at a molecular level, becoming chemically part of the fabric. Also, adding sait, soda ash and/or increase pulp température will help the absorbed dye to be furtherly locked in the fabric to prevent color bleeding and enhance the color depth.

To enhance structural rigidity, a starch component may be added to the slurry, for example, liquid starches available commercially as Topcat® L98 cationic addîtive, Hercobond, and Topcat® L95 cationic additive (available from Penford Products Co. of Cedar Rapids, Iow^ra). Alternatively, the liquid starch can also be combined with low charge liquid cationic starches such as those available as Penbond® cationic additive and PAF 9137 BR cationic additive (also available from Penford Products Co., Cedar Rapids, lowa).

For dry press processes, Topcat L95 may be added as a percent by weight in the range of .5% -10%, and preferably about 1% - 7%, and particularly for products wbich need maintain strength in a hîgh moisture environment most preferably about 6.5%; otherwise, most preferably about 1.5-2.0%. For wet press processes, dry strength additives such as Topcat L95 or Hercobond wdiich are made from modified polyamines that form both hydrogen and ionic bonds with fibers and fines. Diy strength additives help to increase dry strength, as well as drainage and rétention, and are also effective in fixing anions, hydrophobes and sizing agents into fiber products. Those additives may be added as a percent by weight in the range of .5% - 10%, and preferably about 1% - 6%, and most preferably about 3.5%. In addition, both w^ret and dry processes may benefit from the addition of wet strength 13 additives, for example solutions formulated with polyamide-epichlorohydrin (PAE) resin such as Kymene 577 or similar component available from Ashland Specialty Chemical Products at http: // www.ashland.com/products. In a preferred embodiment, Kymene 577 may be added in a percent by volume range of .5% - 10%, and preferably about 1% - 4%, and most preferably about 2% or equal amount with dosing of dry strength additives. Kymene 577 is of the class of polycationic materials containing an average of two or more amino and/or quaternary ammonium sait groups per molécule. Such amino groups tend to protonate in acidic solutions to produce cationic species. Other examples of polycationic materials include polymers derived from the modification with epichlorohydrin of amino containing polyamides such as those prepared from the condensation adipic acid and dimethylene triamine, available commercially as Hercosett 57 from Hercules and Catalyst 3774 from CibaGeigy.

In some packaging applications it is desired to allow air to flow through the container, for example, to facilitate ripening or avoid spoliation of the contents (e.g. tomatoes). However, conventional vacuum tooling typically rinses excess fiber from the mold using a downwardly directed water spry, thereby limiting the size of the resulting vent holes in the finished produce. The présent inventer has determined that re-directing the spray facilitâtes greater fiber removal during the rinse cycle, producing a larger vent hole in the finished product for a given mold configuration.

More particularly, FIG. 5A is a perspective view of an exemplary produce container 500 including extended relief holes 502. FIG. 5B is an end view of a container 504 illustrating extended vent holes 506. In this context, the term “extended vent holes” refers to holes made using the modified tooling shown in FIGS. 9-7, discussed below.

Referring now to FIGS. 6A - 6C, varions combinations of géométrie features may be employed to enhance the structural rigidity/integrity of food containers. By way of non-limiting example, one or more horizontally extending shelfs 602, 604 may be disposed between an upper région and a lower région of a side walL For side walls containing a single shelf, the shelf may be disposed in the range of 30% - 50% of the wall height from the top of the tray, and preferably about 35%. The shelf may be created by indenting the side panel and/or varying the draft angle. For example, in the embodiment shown in FIG. 6C, a lower région 606 exhibits a draft angle in the range of about 4- 6° (and preferably about 5°), while an upper région 608 exhibits a draft angle in the range of about 6- 8° (and preferably about 7°).

With continued reference to FIGS. 6A - 6C, varions rib configurations 610 may be disposed along the bottom and up the side panels of food containers. Ribs may be configured to terminate at a shelf, above the shelf (e.g., in the upper région of a side wall, for example 25% of the distance down from the top edge), below the shelf (e.g., in the lower région of a side wall, for example 25% of the distance down from the shelf), or at the top edge of the side wall. As shown in FIG. 6C, ribs 612 may extend from the bottom of the container upwardly and terminate at the shelf, whereupon subséquent ribs 614 may be off set from the ribs 612 and extend upwardly from the shelf. The ribs may terminate in a rounded, squared, or other desired geometrical shape or configuration.

VENT HOLE TOOLING

FIG. 7 is a directional water impingement cleaning System 700 including a plurality of re-directed spray nozzles 704 configured to rinse excess pulp from vent hole inserts 706. More particularly, a mold (not shown) is covered by a 15 wire mesh 708, the mold including the inserts which correspond to vent holes in the finished product. A supply conduit 702 distributes rinse water to a manifold 711 which includes a plurality of spray nozzles, each configured to direct rinse water to remove excess fiber proximate the inserts.

With momentary reference to FIG. 8, a close up view 800 of a section of a manifold 811 depicts a spray nozzle 802 configured to direct rinse water proximate a corresponding insert 706. In this way, a greater extent of the residual fîbers surrounding the inserts is removed, resulting in extended vent holes in the finished produce vis-à-vis presently known Systems which simply rinse the mold with water sprayed from above. Important!}⁷, the extended vent holes may be realized without having to adjust the underlying mold or inserts.

As seen in FIG. 9, the excess fiber 900 targeted for removal by the improved spray nozzles of the présent invention provides extended vent holes using existing molds and presently known inserts.

MICROWAVABLE CONTAINERS

Building on knowledge obtained from the development of the aforementioned produce containers, the présent inventer has determined that molded fiber containers can be rendered suitable as single use food containers suitable for use in microwave, convection, and conventional ovens by optimizing the slurry chemistry. In particular, the slurry chemistry should advantageously accommodate one or more of the following three performance metrics: i) moisture barrier; ii) oil barrier; and iii) water vapor (condensation) barrier to avoid condensate due to placing the hot container on a surface having a lower température than the container. In this context, the extent to which water vapor permeates the container is related to the porosity of the container, which the présent invention 16 seeks to reduce. That is, even if the container is effectively imperméable to oil and water, it may nonetheless compromise the user expérience if water vapor permeates the container, particularly if the water vapor condenses on a cold surface, leaving behind a moisture ring. The présent inventer has further determined that the condensate problem is uniquely pronounced in fiber-based applications because water vapor typically does not permeate a plastic barrier.

Accordingly, for microwavable containers the présent invention contemplâtes a fîber or pulp-based slurry including a water barrier, oil barrier, and water vapor barrier, and an optîonal rétention aid. In an embodiment, a fiber base of softwood (SW)/bagasse at a ratio in the range of about io% - 90%, and preferably about 7:3 may be used. As a moisture barrier, AKD may be used in the range of about .5% - 10%, and preferably about 1.5% - 4%, and most preferably about 3.5%. As an oil barrier, the grease and oil repellent additives are usually water based émulsions of fluorine containing compositions of fluorocarbon resin or other fluorine-containing polymers such as UNIDYNE TG 8111 or UNIDYNE TG-8731 available from Daikin or World of Chemicals at http://www.worldofchemicals.com/chemicals/cheinical-properties/unidyne-tg8111.html. The oil barrier component of the slurry (or topical coat) may comprise, as a percentage by weight, in the range of .5% - 10%, and preferably about 1% - 4%, and most preferably about 2.5%. As a rétention aid, an organic compound such as Nalco 7527 available from the Nalco Company of Naperville, 111. May be employed in the range of .1% - 1% by volume, and preferably about .3%. Finally, to strengthen the finished product, a dry strength additive such as an inorganic sait Ce.g., Hercobond 6950 available at http://solenis.com/en/industries/tissue- towel/innovations/hercobond-dry-strength-additives/: see also http://www.sfm.state.or.us/CR2K_SubDB/MSDS/HERCOBOND_695o.PDF) may 17 be employed in the range of .5% - 10% by weight, and preferably about 1.5% - 5%, and most preferably about 4%.

As mentioned, vapor barrier performance is directly impacted by porosity of the fiber tray. Reducing the porosity of the fiber tray and, hence, 5 improving vapor barrier performance can be achieved using at least two approaches. One is by improving freeness of the tray material by grinding the fibers. The second way is by topical spray coating using, for example, Daikin S2066, which is a water based long chain Flourione-containing polymer. Spray coating may be implemented using in the range of about 0.1%-3% by weight, and preferably about 0.2% - 1.5 %, ÎO and most preferably about 1%.

Referring now to FIG. 10, an exemplary micro wavable food container 1000 depicts two compartments; alternatively, the container may comprise any desired shape (e.g., a round bowl, elliptical, rectangular, or the like). As stated above, the varions water, oil, and vapor barrier additives may be mixed into 15 the slurry, applied topically as a spray on coating, or both.

MEAT CONTAINERS

Presently known méat trays, such as those used for he display of poultry, beef, pork, and seafood in grocery stores, are typically made of plastic based 20 materials such as polystyrène and Styrofoam, primarily because of their superior moisture barrier properties. The présent inventer has determined that variations of the foregoing chemistries used for microwavable containers may be adapted for use in méat trays, particularly with respect to the moisture barrier (oil and porosity barriers are typically not as important in a méat tray as they are in a microwave 25 container).

Accordîngly, for méat containers the présent invention contemplâtes a fiber or pulp-based slurry including a water barrier and an optional oil barrier. In an embodiment, a fiber base of softwood (SW)/bagasse and/or bamboo/bagasse at a ratio in the range of about io% - 90%, and preferably about 7:3 may be used. As a moisture/water barrier, AKD may be used in the range of about .5% - 10%, and preferably about 1% - 4%, and most preferably about 4%. As an oil barrier, a water based émulsion may be employed such as UNI DYNE TG 8111 or UNIDYNE TG-8731. The oil barrier component of the slurry⁷ (or topical coat) may comprise, as a percentage by weight, in the range of .5% - 10%, and preferably about 1% - 4%, and most preferably about 1.5%. Finally, to strengthen the finished product, a dry strength additive such as Hercobond 6950 may be employed in the range of .5% - 10% by weight, and preferably about 1.5% - 4%, and most preferably about 4%.

As discussed above in connection with the produce containers, the sluriy chemistry may be combined with structural features to provide prolonged rigidity over time by preventing moisture/water from penetrating into the tray.

FIG. 11A is a perspective view of an exemplary méat container 1100, and FIG. 11B is an end view of the méat container shown in FIG. 11A including sidewall ribs 1102 and bottom ribs 1104.

FIG. 12 is a perspective view of an exemplary shallow méat container 1200 including a rib 1202 extending along the bottom and upwardly along the side wall, terminating at a shelf 1204. A second rib 1206, offset from the first rib 1202, extends upwardly from the shelf.

BEVERAGE LIDS

Although fïber and pulp based paper cups are widely known, the beverage industry still needs a sustainable fiber-based lid solution. A significant impediment to the widespread adoption of fiber-based lids surrounds the abilîty to incorporate a zéro or négative draft into the lid, in a manner which allows it to be conveniently removed from the mold. In addition, the fiber-based chemistry must be adapted to provide an adéquate moisture/water barrier so that the rigidity of the lid is not compromised in the presence of liquid. The methods, Chemical formulae, and tooling contemplated by the présent invention addresses both of these issues in a manner heretofore not address by the prior art.

In particular, the chemistry' for lids is similar to méat trays and microwave bowls discussed above. Specifically, for beverage container lids the présent invention contemplâtes a fiber or pulp-based sluriy including a water/moisture barrier and an optional rétention aid. In an embodiment, a fiber base of softwood (SW)/bagasse and/or bamboo/bagasse at a ratio in the range of about io% - 90%, and preferably about 7:3 may be used. As a moisture/water barrier, AKD may be used in the range of about .5% - 10%, and preferably about 1% 4%, and most preferably about 4%. Rigidity may be enhanced by Hercobond 6950 in the range of .5% -10% by weight, and preferably about 1% - 4%, and most preferably about 2% or, alternatively, an equal amount as dry strength additives used in the System. Kymene may also be added in the range of .5% - 10%, and preferably about 1% - 4%, and most preferably about 3%. In various embodiments, the Hercobond and/or the Kymene (or functionally analogous additives) may be added to the slurry before addition of the AKD.

Referring now to FIG. 13, an exemplary lid 1300 includes an inclined platform 1302 surrounded by a retaining wall 1303 designed to urge liquid which leaves the inside of the container toward a sip hole 1304. A small venting 20 aperture 1310 may be disposée! on the platform 1302. A crown 1306 defines a volumétrie space between the top of the cup (not shown) and the platform 1302, and a lock ring 1308 is configured to securely snap around the top of the cup. FIG. 14 is a top view of the lid shown in FIG. 13, including a platform 1402 venting aperture 1410, and sip hole 1404 for comparison.

FIG. 15 is a side élévation view of a lid 1500, highlighting a négative draft 1522 associated with the lock ring. Conventional wisdom suggests that vacuum molded products may not embody zéro or négative draft features, because conventional vacuum mold tooling does not allow the fïnished part to be removed from the tool, inasmuch as the négative draft feature would “lock” the part to the tool in much the same way as the finished part “locks” itself to its mating component (here, the beverage cup). To overcome this limitation, the présent invention contemplâtes a vacuum mold tool which removes the lid from the mold, notwithstanding the presence of the zéro or négative draft locking feature, as described in greater detail below in conjunction with FIGS 13 - 18.

LID TOOLING

A tool for making a fiber-based lid having a zéro or négative draft comprises a rétractable piston having a shape which generally to a mirror image of the lid, and which is configured to extend to unlock the finished lid from that part of the mold which the lid locks to.

Referring now to FIG. 16, is a perspective view of an exemplary mold assembly for use in manufacturing the lid shown in FIGS. 13 - 15 in accordance with varions embodiments. More particularly, a mold assembly 1600 includes a mold block 1620 supporting a lock ring mold portion 1608 (corresponding to the lock ring 1308 of FIG. 13), a rétractable piston assembly comprising a crown portion 21

1630 having an inclined platform 1602 (corresponding to the inclined platform 1302 of FIG. 13), and a shaft portion 1640. In operation, a lid is vacuumed formed in a slurry⁷ bath (not shown) and then transferred onto the hot press shown in Fig 16. A female portion of the lid tool then compresses the wet vacuumed formed lid using heat and pressure.

FIG. 17 is a side élévation view of the mold of FIG. 16 shown in the retracted position. In particular, the crown portion 1706 of the piston is adjacent the lock ring portion 1708 of the mold block 1720 when the piston is in the retracted position shown in FIG. 17. When the lid is formed when pressed, the négative draft portion 1522 of the lid (see FIG 15) locks around the corresponding négative draft portion 1722 of the lock ring portion 1708 of the mold. In order to remove the finished part from the mold, the piston is extended upwardly, forcing the lock ring of the lid to momentarily expand and unlock from the mold.

FIG. 18 shows the piston in the extended position. In particular, the shaft 1840 forces the crown portion 1830 away from the lock ring portion 1808, unlocking the lid from the négative draft feature 1822 of the mold. In an embodiment, the piston is extended pneumatically, and allowed to retract by its 01™ weight once the high pressure air is released.

UTILITY AND SHIPPING CONTAINERS

FIG 19 is a perspective view of utility (non-food) container 1900 including sidewall ribs 1902 and a perimeter lip 1904 in accordance with varions embodiments. Depending on the nature of the contained material, any one or combination of the aforementioned chemistries may be used in the construction of the container. For example, if the contained liquid includes a water component, a suitable moisture/water barrier may be employed; if the contained material includes an oil component, a suitable oil barrier may be employed, and so on.

While the présent invention has been described in the context of the foregoing embodiments, it will be appreciated that the invention is not so limited. For example, the various géométrie features and chemistries may be adjusted to accommodate additional applications based on the teachings of the présent invention.

A method is thus provided for manufacturing a produce container. The method includes: forming a wire mesh over a mold comprising a mirror image of the produce container; immersing the wire mesh in a fiber-based slurry bath; drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the wire mesh surface; and removing the wire mesh from the sluriy bath; wherein the slurry comprises a moisture/water barrier component in the range of 1.5% - 4% by weight.

In an embodiment the slurry' comprises a moisture barrier component in the range of about 4%.

In an embodiment the moisture barrier component comprises alkyltene dimer (AKD).

In an embodiment the moisture barrier component comprises alkyltene dimer (AKD) 80.

In an embodiment the slurry comprises a fiber base of OCC/NP at a ratio in the range of .5/9.5.

In an embodiment the slurry further comprises a dry strength component in the range of 1% - 7% by weight.

In an embodiment the starch component comprises a cationic liquid starch.

In an embodiment the shiriy further comprises a wet strength component such as Kymene (e.g., Kymene 577) in the range of 1% - 4% by weight.

In an embodiment the mold comprises a rolled edge including a vertically descending skirt.

In an embodiment the moisture/water barrier comprises AKD in the range of about 4%, wherein the AKD may be added to the pulp slurry as a diluted solution (e.g., 1:10 ADK:Water); the slurry comprises a cationic liquid starch component in the range of 1% - 7%; and the mold comprises a rolled edge including a vertically descending skirt, at least one bottom rib, and at least one sidewall rib.

A produce container manufactured according to the foregoing methods is also provided.

In a vacuum mold assembly of the type including a wire mesh surrounding a mold form having a substantially vertical insert configured to provide a vent hole in a fmished container, a directional rinse assembly is provided. The directional rinse assembly includes: a water supply conduit; a manifold connected to the water supply conduit; and a spray nozzle connected to the manifold and configured to direct a spray of water at the insert along a vector having a horizontal component.

In an embodiment the mold includes a plurality of substantially vertical inserts, and the directional rinse assembly further includes a plurality of spray nozzles, each configured to direct a spray of water at respective inserts along respective vectors each having a horizontal component.

A method is also provided for manufacturing a zéro or nearly zéro porosity food container. This method includes a wet press procedure as the first step, followed by an extra surface coating procedure for applying a thin layer of water based long chain fluorine-containing polymers such as Daikin S 2066, in the range of 24 about o.5%-6% by weight, and preferably about 1% - 5%, and most preferably about 4%.

A method is also provided for manufacturing a microwavable and/or oven worthy food container. The method includes: forming a wire mesh over a mold comprising a mirror image of the microwavable food container; immersing the wire mesh in a fiber-based slurry bath; drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the wire mesh surface; and removing the wire mesh from the slurry⁷ bath; wherein the slurry comprises a moisture barrier component in the range of .5% - 10% by weight, an oil barrier in the range of .5% 10% by weight, and a rétention aid in the range of .05% - 5% by w^reight.

In an embodiment the moisture/water barrier component is in the range of about 1.5% - 4%, the oil barrier is in the range of about 1% - 4%, and the rétention aid is in the range of about .1% - .5%.

In an embodiment the moisture barrier component comprises alkyltene dimer (AKD).

In an embodiment the moisture barrier component comprises alkyltene dimer (AKD) 79.

In an embodiment the slurry comprises a fiber base of SW/bagasse at a ratio in the range of .5/9.5.

In an embodiment the slurry⁷ further comprises a rigidity component in the range of 1% - 5% by weight.

In an embodiment the rigidity component comprises a dry inorganic sait.

In an embodiment the oil barrier comprises a w^rater based émulsion.

In an embodiment the oil barrier comprises TG 8111.

In an embodiment the rétention aid comprises an organic compound.

In an embodiment the rétention aid comprises Nalco 7527,

In an embodiment the moisture/water barrier comprises AKD in the range of about 4%; the slurry⁷ comprises bagasse and a dry⁷ inorganic sait; the oil barrier comprises a water based émulsion; and the vapor barrier comprises an organic compound.

A microwavable container manufactured according to the foregoing methods is also provided.

A method of manufacturing a méat tray is provided, the method including: forming a wire mesh over a mold comprising a mirror image of the méat tray; immersing the wire mesh in a fiber-based slurry' bath; drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the vire mesh surface; and removing the wire mesh from the slurry bath; wherein the slurry comprises a moisture/water barrier component in the range of .5% - 10% by weight and an oil barrier in the range of .5% - 10% by weight.

In an embodiment the moisture/water barrier component is in the range of about 1% - 4% and the oil barrier is in the range of about 1% - 4.

In an embodiment the moisture barrier component comprises alkyltene dimer (AKD).

In an embodiment the moisture barrier component comprises alkyltene dimer (AKD) 79.

In an embodiment the slurry⁷ comprises a fiber base of SW/bagasse at a ratio in the range of 1/9.

In an embodiment the slurry includes a rigidity component in the range of 1.5% - 4% by weight.

In an embodiment the rigidity component comprises a dry⁷ inorganic sait.

In an embodiment the oil barrier comprises a water based émulsion.

In an embodiment the oil barrier comprises TG 8111 in the range of about 1.5% by weight; the TG8111 may be added to the pulp slurry as a diluted solution (e.g., 1:5, TG8111: Water).

In an embodiment the moisture/water barrier comprises AKD in the range of about 4%; the slurry comprises bagasse and a dry inorganic sait; and the oil barrier comprises a water based émulsion.

A méat tray manufactured according to the foregoing methods is also provided.

In an embodiment the méat tray includes at least one sidewall rib and at least one bottom rib.

A method of manufacturing a lid for a beverage container is also provided. The method includes: forming a wire mesh over a mold comprising a mirror image of the lid; immersing the wire mesh in a fiber-based slurry bath; drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the wire mesh surface; and removing the wire mesh from the slurry bath; wherein the slurry comprises a moisture/water barrier component in the range of .5% - 10% by weight, a rigidity component in the range of 1% - 4% by weight, and a polycationic component in the range of about 1% - 4%.

In an embodiment the moisture/water barrier component is in the range of about 1% - 4% and the oil barrier is in the range of about 1% - 4.

In an embodiment the moisture barrier component comprises alkyltene dimer (AKD).

In an embodiment the moisture barrier component comprises alkyltene dimer (AKD) 80.

In an embodiment the slurry comprises a fiber base of SW/bagasse at a ratio in the range of 1/9.

In an embodiment the slurry further comprises a rigidity component in the range of 1.% - 4% by weight.

In an embodiment the rigidity component comprises a dry inorganic sait.

In an embodiment the moisture/water barrier comprises AKD in the range of about 4%; the slurry comprises bagasse and a dry inorganic sait; and the slurry comprises a polycationic material in the range of about 1% - 4% by weight.

A lid manufactured according to the foregoing methods is also provided.

In an embodiment the lid further includes a lock ring having a nonpositive draft.

A vacuum tool is also provided for manufacturing a fiber-based beverage lid having a crown and a lock ring including a négative draft. The tool includes: a mold block supporting a lock ring mold portion corresponding to the lid lock ring; a rétractable piston assembly comprising a crown mold portion corresponding to the lid crown and a piston shaft; and a pneumatic actuator configured to extend the piston shaft to thereby remove the lid lock ring from the lock ring mold portion.

In an embodiment the vacuum tool further includes a wire mesh removably surrounding the crown mold portion and the lock ring mold portion.

As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Any implémentation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implémentations, nor is it intended to be construed as a model that must be literally duplicated.

While the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing varions embodiments of the 5 invention, it should be appreciated that the particular embodiments described above are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. To the contrary, varions changes may be made in the function and arrangement of éléments described without departing from the scope of the invention.

Claims (5)

1. A slurry for use in vacuum forming a fiber-based microwavable food container, the slurry comprising:

an aqueous pulp mixture comprising fibers ground from at least one of old corrugated containers (OCC) and newsprint (NP);

a moisture barrier component in the range of o.5%-io% of the slurry⁷ weight;

an oil barrier component in the range of o.5%-io% of the slurry weight, where the oil barrier component is different from the moisture barrier component; and a rigidity component in the range of i%-5% of the slurry weight.

2 5 drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the wire mesh surface;

removing the wire mesh including the accumulated fiber partiales in the form of the microwavable food container from the slurry⁷ bath;

at least partially drying the microwavable food container; and applying a vapor barrier to a surface of the at least partially dried

2. A fiber-based slurry⁷ for use in vacuum forming microwavable food trays, the slurry comprising:

a pulp mixture including at least one of old corrugated containers (OCC) and newsprint (NP);

a moisture barrier comprising alkyltene dimer (AKD);

an oil barrier comprising a water based fluorine émulsion; and a rigidity⁷ component comprising liquid starch.

3. A method of vacuum forming a beverage container lid, comprising:

providing a fiber based mixture comprising at least one of softwood (SW) and bagasse;

immersing a mold assembly including a wire mesh comprising a mirror image of the lid into the mixture, wherein the wire mesh comprises a lock ring feature having a non-positive draft région;

drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the wire mesh surface to thereby form a fiber based lid having a lock ring région corresponding to the lock ring feature; and removing the finished lid from the mold assembly by forcing the lock ring région of the lid around the lock ring feature of the mold assembly;

wherein removing comprises urging a piston against an inside surface of the lid.

4. A method of recycling paper products into a produce container using a vacuum molding process, the method comprising:

mixing water, a starch component, a moisture barrier component which is different from the starch component, and at least one of old corrugated containers (OCC) and newsprint (NP) to produce a slurry;

immersing a mesh mold in the shape of the produce container into the slurry;

drawing a vacuum across the mold to thereby form the produce container; and removing the produce container from the slurry and drying the produce container in an oven.

5. A method of manufacturîng a méat tray comprising;

providing a fiber-based slurry mixture including at least one of old corrugated containers (OCC) and newsprint (NP), the slurry mixture further comprising: i) a moisture barrier component; ii) an oil barrier component which is different than the moisture barrier component; and iii) a strength additive component comprising liquid starch;

providing a wire mesh mold in the shape of the méat tray;

immersing the mold in the fiber-based slurry mixture;

drawing a vacuum across the wire mold to cause fiber particles to accumulate at the wire mesh surface; and removing the mold and attached fiber particles from the slurry mixture; and subsequently drying the fiber particles to yield the méat tray.

6. A method of mixing a slurry' for use in vacuum forming a food tray, comprising:

providing a fiber-based slurry mixture comprising at least one of old corrugated containers (OCC), and newsprint (NP):

adding a moisture barrier component in the range of about i%-4% by weight to the slurry mixture; and adding an oil barrier component in the range of about 1.5% by weight to the slurry mixture, wherein the moisture barrier component is different than the oil barrier component.

7. A method of vacuum forming a fiber-based food tray, comprising:

providing a slurry having a fiber base comprising at least one of old corrugated containers (OCC) and newsprint (NP);

adding a moisture barrier and an oil barrier to the slurry, wherein the moisture barrier is different than the oil barrier;

immersing a wire mesh mold in the shape of the food tray into the slurry and drawing a vacuum across the mold to form the food tray; and removing the food tray from the slurry and drying the food tray.

8. A method of manufacturing a microwavable food container comprising the steps of:

preparing a fiber-based slurry mixture including: i) a moisture barrier component comprising alkyl ketene dimer (AKD); ii) an oil barrier component comprising a water based émulsion of fluorine containing at least one of a fluorocarbon resin and a fluorine polymer; and iii) a rigidity component comprising liquid starch in the range of i%-5% by weight;

forming a wire mesh over a mold comprising a mirror image of the microwavable food container;

immersing the wire mesh into the fiber-based slurry mixture;

drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the wire mesh surface;

removing the wire mesh including the accumulated fiber particles in the form 5 of the microwavable food container from the sluriy mixture;

at least partially drying the microwavable food container; and applyîng a vapor barrier to a surface of the at least partially dried microwavable food container, wherein the vapor barrier is different than the oil barrier component.

9. A method of manufacturing a microwavable food container, comprisîng:

I0 preparing a fiber-based slurry mixture including: i) a moisture barrier component in the range of about i.5%-4% by weight; ii) an oil barrier component in the range of about 1-4% by weight; and iii) a rétention aîd in the range of about ο.ίο.5% by weight;

immersing a wire mesh mold in the fiber-based slurry mixture;

15 drawing a vacuum across the wire mesh mold to cause fiber particles to accumulate at the wire mesh surface;

subsequently drying and removing the food container from the mold; and coating at least one of an inside and outside surface of the food container with a vapor barrier that is different than the oil barrier component.

20 10. A method of manufacturing a microwavable food container, comprising:

forming a wire mesh over a mold comprising a mirror image of the microwavable food container;

immersing the wire mesh in a fiber-based slurry comprising a moisture barrier component and an oil barrier component;

5 microwavable food container.