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Title:
SEALABLE PAPERBOARD CONTAINER AND METHOD FOR MANUFACTURING THE SAME
Document Type and Number:
WIPO Patent Application WO/2015/009518
Kind Code:
A1
Abstract:
A method for manufacturing a sealable container including providing a container blank (126), wherein the container blank (126) is marked with indicia, shaping the container blank into a container structure (10), the container structure including an internal side and an external side, and laminating a film material (44) onto the internal side of the container structure, wherein the laminating step includes the step of drawing a vacuum through the container structure to urge the film material toward the container structure.

Inventors:
WADE MICHAEL P (US)
Application Number:
PCT/US2014/046067
Publication Date:
January 22, 2015
Filing Date:
July 10, 2014
Export Citation:
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Assignee:
MEADWESTVACO CORP (US)
International Classes:
B65D25/14; B31B1/00; B65D1/26; B29C51/00; B29C51/10; B29C51/14; B29C51/26; B29K23/00; B29K67/00; B29K305/00; B29K305/08; B29K311/12; B29L31/00
Domestic Patent References:
WO2009138786A22009-11-19
Foreign References:
GB2492828A2013-01-16
US20050161865A12005-07-28
EP0943547A21999-09-22
Attorney, Agent or Firm:
BAUER, Donald et al. (501 South 5th StreetRichmond, Virginia, US)
Download PDF:
Claims:
What is claimed is:

1. A method for manufacturing a container comprising the steps of:

providing a container blank and a film material;

shaping said container blank into a container structure, said container structure comprising an internal side and an external side; and

drawing a vacuum through said container structure to urge said film material onto said internal side.

2. The method of Claim 1 wherein said container blank comprises paperboard.

3. The method of Claim 2 wherein said paperboard is uncoated.

4. The method of Claim 1 wherein said container blank comprises perforations.

5. The method of Claim 1 wherein said container blank is marked with indicia.

6. The method of Claim 1 wherein said providing step comprises the step of cutting said container blank from a web.

7. The method of Claim 6 wherein said providing step further comprises printing indicia onto said web.

8. The method of Claim 1 wherein said shaping step comprises thermoforming said container blank.

9. The method of Claim 1 wherein said container structure comprises:

a base portion;

a side wall extending upward from said base portion; and

a sealing flange extending outward from said side wall.

10. The method of Claim 1 wherein said film material is a layered structure comprising a sealing layer and a functional layer.

1 1. The method of Claim 10 wherein said sealing layer comprises a tie resin.

12. The method of Claim 1 1 wherein said tie resin comprises at least one of ethylene-vinyl acetate copolymer and ethylene methyl acrylate.

13. The method of Claim 10 wherein said functional layer comprises a member selected from the group consisting of polypropylene, polyethylene terephthalate, low density polyethylene and combinations thereof.

14. The method of Claim 1 further comprising the step of heating said film material.

15. The method of Claim 14 wherein said heating step is performed prior to said drawing step.

16. The method of Claim 1 further comprising the step of advancing a plug into contact with said film material to urge said film material against said container structure.

17. The method of Claim 1 further comprising the step of introducing a pressurized gas to urge said film material against said container structure.

18. A container formed from the method of Claim 1.

19. A method for manufacturing a container comprising the steps of:

providing a web of paperboard;

printing indicia onto said web;

die-cutting said printed web to form a container blank;

shaping said container blank into a container structure; and

laminating a film material onto said container structure, wherein said laminating step comprises the steps of:

heating said film material; and

drawing a vacuum through said container structure to urge said heated film material toward said container structure.

20. A container comprising: a container structure comprising an internal side and an external side, wherein indicia are printed on said external side, said container structure defining perforations therein; and a film material laminated onto said internal side.

Description:
SEALABLE PAPERBOARD CONTAINER AND

METHOD FOR MANUFACTURING THE SAME

REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119(e) of United States provisional application serial number 61/856, 116 filed on July 19, 2013 which is hereby incorporated by reference in its entirety.

FIELD

[0002] This application relates to paper-based containers and, more particularly, to paperboard containers and, even more particularly, to the use of vacuum-assisted lamination to manufacture sealable paperboard containers.

BACKGROUND

[0003] Paper-based containers provide an attractive and relatively low cost option for packaging products, such as foodstuffs and consumer goods. Various paper-based containers are known in the art.

[0004] One example of a paper-based container is a molded pulp container. Molded pulp containers are formed by shaping a fibrous slurry in a mold. During the molding process, water is removed from the fibrous material such that the fibrous material takes the shape of the mold. Drying may yield a finished product.

[0005] Unfortunately, molded pulp containers are not easily printable. As such, advertising text and graphics are commonly stenciled onto flat surfaces of molded pulp containers, but the quality is relatively low. Alternatively, advertising text and graphics are introduced with labels that must be applied to appropriate surfaces of the molded pulp containers. However, labeling introduces an additional step, which may increase manufacturing costs, and is less aesthetically pleasing than direct printing.

[0006] Another example of a paper-based container is a paperboard container. Paperboard containers are formed from a blank of paperboard that has been die cut to the desired silhouette. The blank is formed into the desired container shape using various techniques. As one example, the blank may be wrapped around a mandrel to form a cylindrical or frustoconical container body to which a bottom component is connected (e.g., by heat sealing). As another example, the blank may be press-molded (e.g., thermoformed) into the desired shape.

[0007] Paperboard is a porous material. Therefore, the contents of containers formed from paperboard may be exposed to oxygen and/or moisture, which may penetrate through the walls of such containers. Depending on the contents of the container, oxygen and/or moisture penetration may result in product degradation. For example, foodstuffs may degrade much more quickly and, thus, may have a significantly shorter shelf life when packaged in containers that do not significantly exclude oxygen and/or moisture.

[0008] Accordingly, those skilled in the art continue with research and development efforts in the field of paper-based containers.

SUMMARY

[0009] In one embodiment, the disclosed sealable container may include a container structure including an internal side and an external side, wherein indicia are printed on the external side, and a film material laminated onto the internal side by way of a vacuum lamination operation.

[0010] In another embodiment, the disclosed sealable container may include a container structure including an internal side and an external side, wherein indicia are printed on the external side, the container structure defining perforations therein, and a film material laminated on the internal side.

[0011] In another embodiment, the disclosed method for manufacturing a sealable container may include the steps of (1) providing a container blank and a film material; (2) shaping the container blank into a container structure, the container structure including an internal side and an external side; and (3) drawing a vacuum through the container structure to urge the film material onto the internal side.

[0012] In yet another embodiment, the disclosed method for manufacturing a sealable container may include the steps of (1) providing a web of paperboard; (2) printing indicia onto the web; (3) die-cutting the printed web to form a container blank; (4) shaping the container blank into a container structure; and (5) laminating a film material onto the container structure, wherein the laminating step includes the steps of (A) heating the film material and (B) drawing a vacuum through the container structure to urge the heated film material toward the container structure.

[0013] Other embodiments of the disclosed sealable paperboard container and method for manufacturing the same will become apparent from the following detailed description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Fig. 1 is a side cross-sectional view of one embodiment of the disclosed sealable container;

[0015] Fig. 2 is a cross-sectional view of a portion of the sealable container of Fig. 1 ;

[0016] Fig. 3 is a cross-sectional view of a portion of a sealable container in accordance with another embodiment of the disclosure;

[0017] Fig. 4 is a side cross-sectional view of the sealable container of Fig. 1 having a lid connected thereto to seal an object within the container;

[0018] Fig. 5 is a process flow diagram illustrating one embodiment of the disclosed method for manufacturing a sealable container;

[0019] Fig. 6 is a top plan view of container blank formed by the process of Fig. 5;

[0020] Fig. 7 is a schematic side cross-sectional view of an example shaping operation of the process of Fig. 5;

[0021] Fig. 8 is a schematic side cross-sectional view of a first stage of the vacuum laminating operation of the process of Fig. 5;

[0022] Fig. 9 is a schematic side cross-sectional view of a second stage of the vacuum laminating operation of the process of Fig. 5;

[0023] Fig. 10 is a schematic side cross-sectional view of an optional third stage of the vacuum laminating operation of the process of Fig. 5; and [0024] Fig. 11 is a schematic side cross-sectional view of an alternative to the third stage shown in Fig. 10.

DETAILED DES CRIPTION

[0025] Referring to Fig. 1 , one embodiment of the disclosed sealable container, generally designated 10, may include a side wall 12, a base portion 14 and an optional sealing flange 16. The side wall 12 may include a lower portion 18 and an upper portion 20. The base portion 14 may be connected to the side wall 12 proximate the lower portion 18 of the side wall 12. An optional first fillet 22 may be provided at the transition between the base portion 14 and the side wall 12. The sealing flange 16 may be connected to the side wall 12 proximate the upper portion 20 of the side wall 12, and may protrude outward from the container 10. An optional second fillet 24 may be provided at the transition between the side wall 12 and the sealing flange 16.

[0026] Thus, the side wall 12 and the base portion 14 may define an internal volume 26 of the container 10. The upper portion 20 of the side wall 12 may define an opening 28 into the internal volume 26 of the container 10. The sealing flange 16 may extend about the opening 28.

[0027] The container 10 shown in Fig. 1 may be configured as a shallow tray. For example, the tray container 10 may be round, oval, rectangular, square or the like in plan view.

However, those skilled in the art will appreciate that containers 10 having various shapes and configurations, such as cups or cartons, may be formed without departing from the scope of the present disclosure.

[0028] Referring to Fig. 4, the container 10 may be sealed with a lid 30. Various lids 30, such as films (e.g., polymer; metal; metal-polymer combination), press-on lids (e.g., molded plastic lids) and the like, may be used. It is also contemplated that the same (or similar) layered barrier structure (discussed below) used to form the container 10 may be used to form the lid 30.

[0029] During packaging, a product 32 may be placed into the internal volume 26 of the container 10 and the lid 30 may be connected to the sealing flange 16 of the container 10, such as with a heat-seal, an adhesive or an interference fit. The type of lid-to-sealing- flange connection used may depend on, among other possible factors, the type of lid 30 being used. The seal between the container 10 and the lid 30 may be a hermetic seal, though lesser seals may be used depending on the application.

[0030] Referring to Fig. 2, the container 10 (Fig. 1) may be formed from a layered barrier structure 40. The layered barrier structure 40 may include a paper-based substrate layer 42 and a film material layer 44.

[0031] The paper-based substrate layer 42 of the layered barrier structure 40 may be any paper or paperboard-based substrate. As one example, the paper-based substrate layer 42 may include uncoated paperboard, such as solid bleached sulfate board (SBS) or solid unbleached sulfate board (SUS). Without being limited to any particular theory, the use of an uncoated material, such as uncoated SBS, as the paper-based substrate layer 42 may facilitate fluid flow through the paper-based substrate layer 42 at relatively lower energies during the vacuum laminating operation (discussed below) and, thus, may reduce overall costs.

However, other materials, such as coated SBS, coated SUS, natural kraft board (CNK board), coated recycled board (CRB), coated white lined chipboard (WLC), folding boxboard (FBB) and cup stock paperboard, may also be used as the paper-based substrate layer 42.

[0032] The paper-based substrate layer 42 of the layered barrier structure 40 may have a basis weight of at least 85 pounds per 3000 ft 2 . As one specific, non-limiting example, the paper-based substrate layer 42 may have a basis weight of about 100 to about 150 pounds per 3000 ft 2 . As another specific, no n- limiting example, the paper-based substrate layer 42 may have a basis weight of about 150 to about 180 pounds per 3000 ft 2 . As yet another specific, non- limiting example, the paper-based substrate layer 42 may have a basis weight of about 180 to about 220 pounds per 3000 ft 2 .

[0033] The caliper thickness of the paper-based substrate layer 42 of the layered barrier structure 40 may depend on various factors, such as the density of the paper-based substrate layer 42. For example, paper-based substrate layers 42 having caliper thicknesses of 10 points, 14, points, 16 points, 18 points, 20 points, 22 points or more are contemplated. As used herein, 1 point equals 0.001 inches, which equals 25.4 micrometers (μιη). In one specific, non-limiting example, the paper-based substrate layer 42 of the layered barrier structure 40 may have a basis weight of about 205 pounds per 3000 ft 2 and a caliper thickness of about 18 points. [0034] The paper-based substrate layer 42 of the layered barrier structure 40 may have a first (external) side 46 and a second (internal) side 48. The first side 46 of the paper-based substrate layer 42 may form the exterior surface 50 (Fig. 1) of the container 10. Therefore, the first side 46 of the paper-based substrate layer 42 may be marked (e.g., printed) with indicia 52 (Fig. 6), such as advertising text and/or graphics.

[0035] The film material layer 44 may be positioned on the second side 48 of the paper- based substrate layer 42 of the layered barrier structure 40, and may form the interior surface 51 (Fig. 1) of the container 10. The film material layer 44 may include a sealing layer 54 and a functional layer 56. The sealing layer 54, which may be optional, may be positioned between the functional layer 56 and the paper-based substrate layer 42 to connect the functional layer 56 to the paper-based substrate layer 42.

[0036] The sealing layer 54 of the film material layer 44 may be formed from various materials capable of being activated, such as with heat, ultrasonic energy, radiation or the like, to form a seal between the paper-based substrate layer 42 and the functional layer 56. As one specific, non-limiting example, the sealing layer 54 may include a tie resin, such as ethylene-vinyl acetate copolymer (EVA), ethylene methyl acrylate (EMA) copolymer or ionomer polymers such as poly(ethylene-co-methacrylic acid) (EMAA) copolymer, which is commercially available from E. I. du Pont de Nemours and Company of Wilmington, Delaware, under the trademark SURLYN ® . Other examples of suitable sealing materials for forming the sealing layer 54 include, but are not limited to, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE) and high density polyethylene (HDPE). Combinations of sealing materials may be used to form the sealing layer 54.

[0037] The functional layer 56 of the film material layer 44 may be selected to provide the desired functionality, such as a food-safe contact layer, a moisture barrier layer and/or an oxygen barrier layer. Therefore, the composition of the functional layer 56 may vary depending on the desired functionality.

[0038] As one non-limiting example, the functional layer 56 of the film material layer 44 may include polypropylene. As another non-limiting example, the functional layer 56 may include polyethylene terephthalate (PET). As yet another non-limiting example, the functional layer 56 may include a metal, such as aluminum. [0039] Referring to Fig. 3, the film material layer 44 may include multiple functional layers 56A, 56B. While two functional layers 56A, 56B are shown in Fig. 3, those skilled in the art will appreciate that three or more functional layers may be included in the film material layer 44 without departing from the scope of the present disclosure. A tie layer (not shown) may be positioned between, and may connect, the two functional layers 56A, 56B.

[0040] The disclosed container 10 (Fig. 1) may be formed by (1) shaping a container blank formed from a paper-based substrate into a container structure and (2) vacuum laminating a film material onto the container structure. The paper-based substrate used to form the container structure may correspond to the paper-based substrate layer 42 (Fig. 2) of the layered barrier structure 40 (Fig. 2) of the finished container 10 and the film material applied by vacuum lamination may correspond to the film material layer 44 (Fig. 2) of the layered barrier structure 40.

[0041] Referring to Fig. 5, disclosed is a method, generally designated 100, for

manufacturing a container, such as the container 10 shown in Fig. 1. The method 100 may include a printing operation 102, a cutting operation 104, a shaping operation 106 and a vacuum laminating operation 108. Additional steps may be included in during the manufacture of the disclosed container without departing from the scope of the present disclosure. Once the container is manufactured, downstream steps, such as filling 1 10 and lidding 112, may be performed.

[0042] The method 100 may begin with a web 120 of a paper-based substrate. The web 120 may form the paper-based substrate layer 42 (Fig. 2) of the layered barrier structure 40 (Fig. 2) of the finished container 10 (Fig. 1). The web 120 may be unwound from a roll 122 and directed to the printing operation 102 and the cutting operation 104 by a take-up roll 124.

[0043] The printing operation 102 may mark the first side 46 of the web 120 with indicia 52 (see also Fig. 6). Optionally, though not shown, the second side 48 of the web 120 may also be marked with indicia. The printing operation 102 may include any apparatus or system capable of marking the web 120 with indicia 52.

[0044] As one general, non-limiting example, the printing operation 102 may include a printing press capable of printing high quality text and/or graphics (e.g., advertising text and graphics) onto the first side 46 of the web 120. Specific examples of suitable printing techniques include, but are not limited to, offset printing, gravure printing, flexographic printing and digital printing.

[0045] The cutting operation 104 may cut container blanks 126 from the web 120. The cutting operation 104 may include any apparatus or system capable of cutting container blanks 126 from the web 120. For example, the cutting operation 104 may include a die cutting machine.

[0046] Referring to Fig. 6, the cutting operation 104 may provide the container blank 126 with the desired silhouette. While the container blank 126 shown in Fig. 6 has an oblong silhouette configured to form a shallow tray, those skilled in the art will appreciate that the silhouette of the container blank 126 may depend on the intended shape and configuration of the final container. Furthermore, the cutting operation 104 may cut the web 120 such that the indicia 52 are positioned at the desired and proper location on the container blank 126.

[0047] The cutting operation 104 (Fig. 5) may also form a plurality of perforations 128, such as micro perforations, in the container blank 126. The perforations 128 may be uniformly or randomly spaced across the container blank 126, and may extend through the cross-section of the container blank 126 (e.g., from the first 46 to the second side 48 (Fig. 5)). Without being limited to any particular theory, it is believed that the perforations 128 may facilitate fluid flow through the paper-based substrate at relatively lower energies during the vacuum laminating operation (discussed below) and, thus, may reduce overall costs.

[0048] The cutting operation 104 (Fig. 5) may also form weakening features 130, such as creases and/or score lines, in the container blank 126. The weakening features 130 may facilitate shaping the container blank 126 into the desired container structure during the shaping operation 106 (Fig. 5).

[0049] Referring back to Fig. 5, the cutting operation 104 may yield a supply 132 of container blanks 126. The container blanks 126 may be supplied to the shaping operation 106 to convert the container blanks 126 into container structures 134 (Fig. 7).

[0050] The shaping operation 106 may shape each container blank 126 into a corresponding container structure 134 (Fig. 7) having the desired shape and configuration. The shaping operation 106 may include any apparatus or system capable of shaping a container blank 126 into a container structure 134. [0051] As one general, non-limiting example, the shaping operation 106 may include a press mold. As one specific, non-limiting example, the shaping operation 106 may include a thermoforming mold 140, as shown in Fig. 7. The thermoforming mold 140 may include a positive mold component 142 and a negative mold component 144. The mold components 142, 144 may be heated such that both pressure and heat may be applied to the container blank 126 (Fig. 6) to thermoform the container structure 134.

[0052] Referring back to Fig. 5, the container structures 134 (Fig. 7) formed by the shaping operation 106 may be supplied to the vacuum laminating operation 108. The vacuum laminating operation 108 may apply a film material 150 (Fig. 8) to the internal side 48 of the container structures 134 to produce a supply 148 of containers 10. The film material 150 applied by the vacuum laminating operation 108 may form the film material layer 44 (Fig. 2) of the layered barrier structure 40 (Fig. 2) of the finished container 10 (Fig. 1).

[0053] As shown in Figs. 8 and 9, the vacuum laminating operation 108 (Fig. 5) may draw a vacuum through the container structure 134. The vacuum may urge the film material 150 toward the internal side 48 of the container structure 134 such that the film material 150 is applied to, and takes the contour of, the container structure 134.

[0054] In one particular implementation, the vacuum laminating operation 108 may include a vacuum mold 152 coupled to a vacuum source 154. A container structure 134 may be positioned in the vacuum mold 152 and the vacuum source 154 may be actuated to draw air through the container structure 134, thereby drawing the film material 150 against the internal side 48 of the container structure 134.

[0055] As shown in Fig. 8, a heater 156 may heat the film material 150 prior to the film material 150 being applied to the container structure 134 or while the film material 150 is being applied to the container structure 134. Heat from the heater 156 may render the film material 150 more pliable such that the film material 150 more readily takes the shape of the container structure 134. Additionally, heat from the heater 156 may activate the sealing layer (see sealing layer 54 in Fig. 2) of the film material 150 such that the film material 150 adheres to the container structure 134.

[0056] At this point, those skilled in the art will appreciate that if the sealing layer 54 includes a sealing material other than a heat-sealing material (e.g., a UV or RF activated sealing material), the appropriate activating equipment may be used in addition to, or substituted for, the heater 156.

[0057] Referring to Figs. 10 and 1 1, the vacuum laminating operation 108 may be assisted with a positive force that pushes the film material 150 against the container structure 134, which may be in addition to the negative (vacuum) force that pulls the film material 150 against the container structure 134. As one example, a plug 160 may be advanced into the container structure 134 to push the film material 150 against the container structure 134, as shown in Fig. 10. As another example, an air nozzle 170 may direct a pressurized gas (e.g., pressurized air) against the film material 150 to push the film material 150 against the container structure 134, as shown in Fig. 1 1.

[0058] Thus, the vacuum laminating operation 108 may output a supply 148 of finished containers 10, as shown in Fig. 5. The film material 150 adhered to the container structure 134 may form the layered barrier structure 40 (Fig. 2) of the finished containers 10.

[0059] Referring back to Fig. 5, the supply 148 of containers 10 may be filled with product 32 (Fig. 4) at the filling operation 1 10 and then sealed with a lid 30 (Fig. 4) at the lidding operation 112.

[0060] Accordingly, the disclosed method 100 (Fig. 5) may form a container 10 (Fig. 1) from a layered barrier structure 40 (Fig. 2), wherein the container 10 is sealable with a lid 30 (Fig. 4), and wherein the container 10 is printed with indicia 52 (Fig. 6), such as high quality advertising text and graphics.

[0061] Although various embodiments of the disclosed sealable paperboard container and method for manufacturing the same have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.