Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
  • B65D81/24—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants
  • B65D81/26—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants with provision for draining away, or absorbing, or removing by ventilation, fluids, e.g. exuded by contents; Applications of corrosion inhibitors or desiccators
  • B65D81/264—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants with provision for draining away, or absorbing, or removing by ventilation, fluids, e.g. exuded by contents; Applications of corrosion inhibitors or desiccators for absorbing liquids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
  • B65D65/38—Packaging materials of special type or form
  • B65D65/40—Applications of laminates for particular packaging purposes
  • B65D65/403—Applications of laminates for particular packaging purposes with at least one corrugated layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
  • B65D81/24—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants
  • B65D81/26—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants with provision for draining away, or absorbing, or removing by ventilation, fluids, e.g. exuded by contents; Applications of corrosion inhibitors or desiccators
  • B65D81/261—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants with provision for draining away, or absorbing, or removing by ventilation, fluids, e.g. exuded by contents; Applications of corrosion inhibitors or desiccators for draining or collecting liquids without absorbing them
  • B65D81/262—Rigid containers having false bottoms provided with passages for draining and receiving liquids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B50/00—Making rigid or semi-rigid containers, e.g. boxes or cartons
  • B31B50/59—Shaping sheet material under pressure
  • B31B50/592—Shaping sheet material under pressure using punches or dies

Definitions

• the present invention relates to a method of forming corrugated paperboard containers, including food containers and food trays and, in particular, employing corrugated paperboard in a novel stamping process, which paperboard has an increased frequency of flutes in its internal layer, such that upon introducing the corrugated paperboard to the stamping process, the paperboard does not break apart and is capable of being molded to produce a satisfactory unitary structure.
• corrugated paperboard for containers has been limited to an expensive multi-step manufacturing process in which the paperboard must first be printed, then die cut and then passed through complex box folding machinery. Accordingly, a corrugated paperboard that would permit pressing and forming (stamping) into a container and a method of pressing and forming corrugated paperboard container would be desirable.
• a method of forming a unitary container from corrugated paperboard comprises introducing corrugated paperboard having an outer flat layer of paperboard and an internal contoured layer of paperboard having a high frequency, per linear meter of paperboard, of flutes formed from alternating upper and lower curved surfaces into a die press and pressing the paperboard between a die and a cavity to apply pressure to the paperboard. Applying heat to the paperboard simultaneously with the application of pressure.
• a three-layered corrugated paperboard tray is provided.
• the paperboard is formed of a first layer of corrugated paper, a second layer of industrial strength paper, and a third layer of paper having holes formed therein, the corrugated layer being sandwiched between the second layer and third layer.
• the top paper layer comprises a sheet of paper having a plurality of holes therein resting on the fluted crests of the corrugated layer.
• the upper surface of the top perforated layer is moisture resistant.
• the underside of the fluted layer and the bottom layer of the corrugated construction have moisture-resistant barriers to prevent leaking through the entire tray.
• Another object of the invention is to form a container from corrugated paper by stamping, without the need for a complex box folding machinery or the need for die cutting.
• Yet another object of the invention is to form a unitary box from single face or single ply corrugated paper.
• a further object of the invention is to provide a container made out of lighter, cheaper and recyclable materials.
• Still another object of the invention to provide a method for forming complex shapes by pressing and forming paperboard.
• FIG. 1 is a partial perspective view of the paperboard utilized in connection with the invention
• FIG. 2 is a front elevated view of the paperboard constructed in accordance with the invention.
• FIG. 3 is a sectional view of stamp used in connection with the method of the invention.
• FIG. 4 is a perspective view of a container constructed in accordance with the invention.
• FIG. 5 is a perspective view of the paperboard food tray constructed in accordance with another embodiment of the present invention.
• FIG. 6 is a partial top plan view of a paperboard utilized in connection with the present invention.
• FIG. 7 is a cross-sectional view taken along line 3-3 of FIG. 5 of the paperboard utilized in connection with the present invention.
• FIGS. 1 and 2 wherein a paperboard, capable of being pressed and formed (stamped), generally indicated as 10, comprising two layers is depicted.
• An outer layer 12 is flat paperboard having a thickness in the range of 0.3 mm to 1.5 mm.
• An internal layer, generally indicated as 14, of paperboard 10 is contoured, having a thickness in the range of 0.23 mm to 0.5 mm.
• the internal contoured layer 14 consists of flutes 16, each flute being formed by one of an alternating upper 18 or lower 20 curved surface.
• Internal layer 14 is glued to an inner surface 22 of the outer layer 12 along the lower curved surfaces 20. Gluing the lower curved surfaces 20 of the internal layer 14 to the inner surface 20 of the outer layer 12 allows for the formation of exposed ridges 24 and grooves 26 (FIG. 2) across the unattached surface of internal layer 14.
• Internal layer 14 has a high frequency (flutes/meter) of flutes 16 and a corresponding high frequency of ridges 24 on the exposed surface of internal layer 14 allowing the paperboard 10 to be pressed into a unitary structure.
• One upper curved surface 18 and an alternating lower curved surface 20 make up one set of flutes 28.
• Each flute 16 has a height in the range of 0.9 mm to 1.2 mm or 0.035 inches to 0.047 inches, and sets of flutes 28 in the internal layer 14 have frequency within the range of 350-400 sets of flute 26 per linear meter of paperboard 10.
• the number of sets of flutes is 375 per linear meter of paperboard, the flute repeat length to flute height ratio is 2.6 or less, and the corresponding number of ridges on the top surface of the internal layer is 6 to 12 ridges per inch.
• internal contoured layer 14 has glue applied to the lower curved surfaces 20.
• Outer layer 12 and internal layer 14 are passed through rollers under a sufficient pressure to compress the two layers together to adhere them.
• lower curved surfaces 20 adhere to inner surface 22 of the outer layer 12 and the pressure causes the lower curved surfaces 24 to imbed and become indented into inner surface 20 of outer layer 12 by at least 0.1 mm (0.004 inches).
• the amount of indent (or imbedding) is 0.2mm (0.008").
• the flutes in the stampable paperboard have a higher frequency and higher amplitude when compared with other fluted paper. This maximizes the ratio of flute repeat length to flute height. Because of the more vertical flute rise at the midpoint between flute tips there is a greater rate of change of height over distance so that for a given height of flute rise, the corrugated paperboard will have a smaller repeat ratio when compared to E- flute or F-flute, by way of example, and for a given repeat ratio the described paperboard will have a higher amplitude than E-flute or F-flute corrugated paperboard.
• the stampable corrugated paperboard has a flute repeat length to flute height ratio of 2.6, whereas in E-flute or F-flute, the flute repeat length to flute height ratio is 2.8.
• the corrugated paperboard described above does not break up in the molding/stamping process and, instead, is able to be molded into a unitary structure. This ability to mold the corrugated paperboard into a unitary structure is specifically due to the high density of fluting in the corrugation.
• single-face corrugated paperboard comprising a flat outer layer and an internal contoured layer comprising a flute repeat length to flute height ratio of 2.6 is pressed and formed by introducing the single-face corrugated paperboard into a stamp and applying pressure and temperature for an amount of time such that the corrugated paperboard becomes pressed and formed to form a unitary container.
• the high frequency of flutes and ridges in the internal layer cause the single face paperboard to be stamped by this method to form a satisfactory unitary structure such as a container.
• FIG. 3 is a stamp used in conjunction with the method for stamping the corrugated paper as shown.
• moisture is added to the paperboard to soften the fibers .
• Moisture is added until the moisture level of each sheet is 8 to 11%, however, it is best to run as close to the lower end of this range in an exemplary embodiment to prevent excessive moisture forming steam beneath any coating applied to the paperboard in the forming process causing the coating to blister.
• An additive such as fluorocarbon is added to the moistening process to achieve about a 1% solution in water. The additive assists in water retention, aids forming and reduces grease wicking in the final process.
• the moisture and fluorocarbon applied to the paperboard does not immediately penetrate the sheet so that the sheet remains stiff and difficult to form at first. Additionally, latent moisture may still be laying on top of the sheet, having not been absorbed by the fibers, therefore in an exemplary embodiment, the paperboard sits for forty-eight to seventy-two hours before forming, allowing the board to reach equilibrium and to obtain a more uniform distribution of moisture throughout the cross-section of the sheet.
• the paperboard is deep drawn utilizing a stamp, generally indicated as 100.
• the stamp includes a bolster plate 102 upon which is seated a heated female cavity 104.
• a plunger is slidably mounted on bolster plate 102 to move into and out of heated female cavity 104.
• a top die mounting plate 108 slidably supports a reciprocating platen 110.
• Platen 110 is attached to a male die 112.
• Male die 112 moves towards and is received in heated female cavity 104 with the reciprocating motion of platen 110.
• a draw ring 114 is mounted about male die 112 for positing paperboard prior to stamping.
• the method of pressing or stamping the paperboard consist of the basic steps of feeding the paperboard, creasing the paperboard, cutting the paperboard and forming the paperboard.
• the moistened paperboard is creased in an area where corners will be formed while the paperboard blank is formed in a web.
• the web is then advanced a predetermined amount centering the creased paperboard between male die 112 and heated female cavity 104.
• Reciprocating platen 110 pushes male die 112 through the die cavity 104, shearing the registered pre-creased paperboard from the remainder of the web and urging it to fall through the die creating the blank.
• the pre-creased cut blank falls through and is centered between male die 112 and draw ring 114 and heated female cavity 114 mounted on bolster plate 102.
• Draw ring 114 is extended and contacts the paperboard, tensioning the paperboard as male die 112 descends pushing the paperboard into female cavity 104.
• the draw ring holds the board tightly against the rim of the female cavity to discourage wrinkles from forming on the side panels of the container as it is being drawn.
• the draw ring 114 further forces excess paper into the corners and insures that neat, even folds are made, following the pre-creased lines. The more tension applied to the paperboard during forming, the neater the folds and fewer wrinkles formed on the side panels.
• the press extends the male die slightly, depressing the female cavity 104 and bolster plate 102 by 1/30 seconds of an inch holding the tray under pressure and heat.
• the pressure applied is approximately four tons at 120°F. This allows the moisture in the board to turn into steam and escape through vents provided in the die, setting the paperboard in the shape of the die. Essentially, the folds in the corners are steam ironed into the form of the container, imparting a structural integrity to the container.
• the stamp (press) is then opened and plunger 106 is activated entering female cavity 104 ejecting the container from the heated female cavity. The excess paper is then trimmed from the formed container.
• FIG. 4 shows a corrugated paperboard container, generally indicated as 200, made by the stamping process of the present invention.
• the container has a clam shell construction and includes a lower compartment 210 for receiving food and the like and an upper compartment 240 for covering and closing the container.
• Lower compartment 210 includes a base 212 and four upstanding sidewalls 214, 216, 218 and 220, integrally formed with base 212 along fold line 222 formed during stamping.
• Wall 214 is coupled to wall 216 along a curve at connecting wall 224 formed during stamping.
• wall 216 is coupled to wall 218 by a curved wall 226, wall 218 is coupled to wall 220 by curved wall 228 and curved wall 220 is formed integrally with front wall 214 by a curved wall 230.
• curved walls 224, 226, 228, 230 are formed during stamping and easily could be formed as fold lines .
• Wall 214 is formed with a lip 232 at an acute angle with wall 214 and having slot 234 formed therein.
• Upper compartment 240 is similar in construction to lower compartment 210 and includes a top wall 242 and side walls 244, 246, 248 and 250, each of walls 244, 246, 248 and 250 are coupled to top wall 242 along a fold line 252 formed during stamping. Side walls 244, 246, 248 and 250 are also integrally coupled, each adjacent sidewall by a respective curved wall 254, 256, 258 and 260. Side wall 248 of upper compartment 240 and side wall 218 of lower compartment 210 are pivotably coupled together by a hinge 262 formed as a fold line between lower compartment 210 and upper compartment 240 during the stamping process. Upper compartment 240 rotates about hinge 262 in the direction of arrow A to close container 200 upon itself.
• Side wall 244 is also formed with a lip 264 having a tab 266 formed thereon. Tab 266 is received within slot 234 to fasten upper component 240 to lower component 210.
• bottom compartment is formed with a receiving lip adapted to receive a lip about upper compartment 240 to further seal in a mating relationship, container 200.
• upper compartment 240 and lower compartment 210 are each formed from paperboard 10 including outer layer 12 to which is glued one contoured internal layer 14.
• Contoured interior layer 14 consists of flutes 16 which are formed by alternating upper 18 and lower 20 curved surfaces. In a preferred embodiment the ratio of flute repeat length to flute height is 2.6 or less.
• the paperboard employed may be solid bleached sulfate (SBS) or chipboard, or a recycled material.
• outer flat layer 12 may be chipboard
• internal layer 14 may be a recycled paperboard medium.
• the outer layer 12 has a thickness of 0.007 inches (7 points) and internal contoured layer 14 has a thickness of 0.040 inches (40 points).
• the two layers together may have a working range from 30 to 60 points from the outer surface of outer layer 12 to the ridged top of internal layer 14. As a result, less paperboard is used, the container is light in weight, and although the container maintains its strength and rigidity as if layers were solid paperboard, it, at the same time, possesses the capability of becoming stamped.
• the internal surfaces of walls 212, 214, 216 and 218 as well as 242, 244, 246 and 258 of compartments 210 and 240 are formed with ridges having upper ridges 24 and grooves 26 between ridges 24. There are 6 to 12 ridges per inch, and, in a preferred embodiment, there are 9 ridges per inch.
• the upper ridges 24 of bottom wall 212 form a raised food-receiving surface on which the food is placed. Any moisture given off by the hot food within the container is received and collected within grooves 26. In this manner, the collected moisture is not absorbed by the food, and container 200 prevents the food from becoming soggy.
• internal layer 14 is coated with a water-based coating prior to stamping.
• the coating is repulpable, recyclable, and resists the penetration of moisture given off by the hot food.
• the molded paperboard container maintains its strength and rigidity.
• FIGS. 5 and 6 wherein a portion of a laminated paperboard 10 utilized in constructing a food tray 300, comprising three layers in accordance with another embodiment of the invention is depicted. Two of the layers are similar in construction to the paperboard described above, the difference being the addition of a waterproof barrier. Like numerals are utilized to identify like structures.
• a first outer layer 12 is flat paperboard having a thickness in the range .15 mm to 1.0 mm.
• An internal layer generally indicated as 14 of paperboard 10 is contoured, having a thickness in the range of .15 mm to .25 mm.
• Internal contoured layer 14 consists of flutes 16, each flute being formed by one of an alternating upper 18 or lower 20 curved surface.
• Internal layer 14 is glued to an inner surface 22 of the outer layer 12 along the lower curved surfaces 20. Gluing the lower curved surfaces 20 of the internal layer 14 to the inner surface 22 of the outer layer 12 allows for the formation of exposed ridges 24 and grooves 26 across the upper surface of internal layer 14.
• Internal layer 14 has a high-frequency (flutes/meter) of flutes 16 and the corresponding high frequency of ridges 24 in the upper surface of internal layer 14.
• a moisture barrier coating 27 is provided on upper surface 22 of outer barrier layer 12.
• a similar moisture barrier (not shown) coating 29 is provided on the bottom surface of internal layer 14. The top surface of layer 14 is uncoated and therefore absorbs moisture coming in contact therewith. Barrier coatings 27, 29 create a moisture barrier which retains moisture captured by internal layer 14 within layer 14, and protects the tray from leakage.
• Each flute 16 has a height in the range of 0.9 mm to 1.2 mm or 0.35 inches to 0.047 inches, and sets of flutes 28 in the internal layer 14 have frequency within the range of 350-400 sets of flute 26 per linear meter of paperboard 10.
• the number of sets of flutes is 375 per linear meter of paperboard, the flute repeat length to flute height ratio is 2.6 or less, and the corresponding number of ridges on the upper surface of internal layer 14 is 6 to 12 ridges per inch.
• the high flute frequency provides a greater exposed layer surface per meter increasing the area of absorbing surfaces in layer 14.
• Perforated top layer 30 is provided above internal layer 14.
• Layer 14 has a thickness and construction similar to that of outer layer 12.
• perforated openings 34 are provided uniformly on the surface of layer 30.
• Top layer 30 is glued at an inner surface to curved upper surface 18 of internal layer 14, in a way similar to that of gluing inner surface 22 of outer layer 12 along the lower curved surfaces 20 of internal layer 14.
• Perforated openings 34 are provided at regular intervals in upper layer 30, which allow liquid to flow through upper layer 30, and come in contact with exposed surfaces on fluted internal layer 14.
• the regularly spaced openings 34 each encompass two complete upper curved surfaces 18 of ridges 24. These holes are spaced at a distance of 1/2 or 12.7 mm in a checkerboard pattern.
• top surface of upper layer 30 is coated with a moisture barrier coating 33 protecting the upper surface from liquid being absorbed through the top of layer 30.
• a moisture barrier coating 33 protecting the upper surface from liquid being absorbed through the top of layer 30.
• Paperboard 10 by its construction, is stampable.
• internal contoured layer 14 has glue applied to lower curved surfaces 20 and upper curved surfaces 18.
• Outer layer 12, internal layer 14, and upper layer 30 are passed through rollers under a sufficient pressure to compress the three layers together to adhere them.
• lower curved surfaces 20 and upper curved surfaces 18 adhere to inner surfaces 22 and the lower surface of upper layer 30, respectively, and the pressure causes lower curved surfaces 24 and upper curved surfaces 18 to embed and become indented into inner surface 20 of outer layer 12 and the lower surface of top layer 30 by at least 0.1 mm (0.004 inches).
• the amount of indent (or embedding) is 0.2 mm (0.008 inches).
• the high frequency of flutes (16 per inch) and the corresponding increased number of ridges (24 across the upper surface of internal layer 14) causes the flats between curves 18 and 20 in each of the flute sets 28 to become more vertical, and this adds strength during compression so that the paperboard can be pressed and formed. Accordingly, by increasing the number of flutes 16, and hence the number of ridges 24, the ability of the corrugated paperboard to be pressed and formed consequently increases .
• triple-layer corrugated paperboard comprising a flat outer layer, and internal contoured layer comprising a flute repeat length to flute height ratio of 2.6, and an upper flat top layer with evenly spaced apertures therein is pressed and formed by introducing the three layer corrugated paperboard into a stamp and applying pressure and temperature for an amount of time such that the three- layer paperboard becomes pressed and formed to form a unitary tray.
• the high frequency of flutes and ridges in the internal layer causes the triple-layer paperboard to be stamped by this method to form a satisfactory unitary structure such as a food tray.
• Tray 300 is then formed as described above in connection with stamp 100 shown in FIG. 3.
• FIG. 5 shows a corrugated paperboard tray, generally indicated as 300, made by the stamping process of the present invention.
• Tray 300 includes a base 312 and four upstanding angled side walls 314, 316, 318 and 320, integrally formed with base 312 along fold line 322 formed during stamping. In a preferred embodiment, these angled sidewalls are disposed at a predetermined angle of 142° to the base.
• Wall 314 is coupled to wall 316 along a curved wall 324 formed during stamping.
• wall 316 is coupled to wall 318 by a curved wall 326
• wall 318 is coupled to wall 320 by curved wall 328
• curved wall 320 is formed integrally with front side wall 314 by curved wall 330.
• corrugated paperboard container 300 is formed from paperboard 10 including outer layer 12 to which is glued contoured internal layer 14 to which, in turn, is glued top layer 30, including moisture barrier layer 33, and evenly spaced circular apertures 31.
• Contoured interior layer 14 consists of flutes 16 which are formed by alternating upper 18 and lower 20 curved surfaces. In a preferred embodiment, the ratio of flute repeat length to flute height is 2.6 or less.
• ridges 24 and grooves 26 are formed on the upper surface of internal layer 14.
• ridges 24 and grooves 26 are partially covered by upper layer 30 in the portions not comprised of regularly spaced perforated openings 34.
• the paperboard employed may be solid bleach sulfate (SBS) or chipboard, or a recycled paper or paperboard or container board material.
• outer flat layer 12 may be chipboard
• internal layer 14 may be a recycled paperboard medium
• upper layer 30 may be chipboard.
• the outer layer 12 has a thickness 0.007 inches (7 points)
• internal contoured layer 14 has a thickness of 0.040 inches (40 points)
• upper layer 30 has a thickness of 0.007 inches (7 points).
• the three layers together may have a working range from 35 to 70 points from the outer surface of layer 12 to the upper surface of top layer 30. As a result, less paperboard is used and the container is light in weight.
• top layer 30 During use, food is placed in the container. As juices or other fluids leak from the food, they fall through perforated openings 34 in top layer 30. The uncoated lower surface of top layer 30 and the upper surface of internal layer 14 absorb the liquid, removing it from the food. The liquid is retained in internal layer 14 and top layer 30 by moisture barriers 27, 29 and 30 so that tray 10 does not leak over time.
• the internal surfaces of walls 312, 314, 316 are formed with upper layer 30 and circular apertures 31 overlaying ridges having upper ridges 24 and grooves 26 between ridges 24.
• the perforated upper layer 30 overlaying upper ridges 24 forms a moisture wicking, raised food receiving surface on which food is placed. Any moisture given off by the food within the tray is wicked away from the food through perforated openings 34 in top layer 30 and collected within grooves 26 of internal layer 14.
• tray 300 prevents the food from becoming soggy, or from spoiling by remaining in contact with this moisture. There is no longer a need for a liquid absorbing napkin.
• the tray would operate in a similar manner if top layer 30 had no perforations and was not coated with a moisture proof barrier.
• internal layer 14 is coated with a water-based coating prior to stamping.
• the coating is repulpable, recyclable and resists the penetration of moisture given off by food.
• This coating 29 is placed on the bottom of internal layer 14. As a result, the molded paperboard container maintains its strength and rigidity.
• a similar coating 33 is placed on the upper surface of upper layer 30.
• this layer is not applied to layer 30 where perforated openings 34 exist.
• upper layer 30 becomes impenetrable to moisture, and all moisture is wicked away from the food in tray 300 through perforated openings 34 in upper layer 30.
• the container formed by the process of this invention is shown to have a particular shape, it should be understood that the stamping process for corrugated paperboard can be used to form a corrugated container of any shape, such as round, square, rectangular or oval, as well as non-container structures such as trays or the like.
• a method of stamping corrugated paperboard having an internal contoured layer containing a high frequency of flutes and a food container formed by the method of stamping corrugated paperboard such food container being able to resist the penetration of moisture, is rigid and strong, is light in weight and collects moisture in troughs or grooves to prevent food from becoming soggy.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Food Science & Technology (AREA)
• Containers Having Bodies Formed In One Piece (AREA)
• Making Paper Articles (AREA)
• Container Filling Or Packaging Operations (AREA)
• Cartons (AREA)
• Auxiliary Devices For And Details Of Packaging Control (AREA)
• Pressure Welding/Diffusion-Bonding (AREA)
• General Preparation And Processing Of Foods (AREA)

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• 1995
  • 1995-06-19 AT AT95923944T patent/ATE197932T1/de not_active IP Right Cessation
  • 1995-06-19 AU AU28642/95A patent/AU2864295A/en not_active Abandoned
  • 1995-06-19 WO PCT/US1995/007722 patent/WO1995035204A1/fr active IP Right Grant
  • 1995-06-19 DE DE69519573T patent/DE69519573T2/de not_active Expired - Fee Related
  • 1995-06-19 ES ES95923944T patent/ES2156208T3/es not_active Expired - Lifetime
  • 1995-06-19 JP JP8502520A patent/JPH10502585A/ja active Pending
  • 1995-06-19 CA CA002193386A patent/CA2193386A1/fr not_active Abandoned
  • 1995-06-19 EP EP95923944A patent/EP0766622B1/fr not_active Expired - Lifetime
  • 1995-06-19 EP EP00201024A patent/EP1023992A3/fr not_active Withdrawn

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