WO2015171443A1

WO2015171443A1 - Paperboard barrier structure and container

Info

Publication number: WO2015171443A1
Application number: PCT/US2015/028695
Authority: WO
Inventors: William Statelman
Original assignee: Westrock Mwv, Llc
Priority date: 2014-05-07
Filing date: 2015-05-01
Publication date: 2015-11-12

Abstract

A paperboard barrier structure including a substrate having a first side and a second side, a first sealing layer on the first side of the substrate, a laminated film layer on the second side of the substrate, the laminated film layer including a first film layer connected to a second film layer, wherein the first film layer and/or the second film layer includes a barrier coating, and wherein the barrier coating is positioned between the first and second film layers, and a second sealing layer positioned over the laminated film layer such that the laminated film layer is positioned between the substrate and the second sealing layer.

Description

PAPERBOARD BARRIER STRUCTURE AND CONTAINER

FIELD

[0001] This application relates to paperboard barrier structures and, more particularly, to containers formed from paperboard barrier structures.

BACKGROUN D

[0002] Paper-based containers typically are formed from a blank, such as a blank of paperboard (e.g., solid bleached sulfate paperboard). The blank is die cut to the desired silhouette and then the blank is formed into the desired container shape. For example, the blank may be wrapped around a mandrel to form a cylindrical or frustoconical container body. A bottom component is typically connected to the container body to enclose the lower end of the container body. After filling the container, a lid component is typically connected to the container body to fully enclose the container.

[0003] Unfortunately, the contents of paper-based containers may be exposed to oxygen and/or moisture, which may penetrate through the wails 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.

[0004] Thus, paper-based containers have been formed from substrates having barrier properties. For example, functional barrier layers, such as oxygen and moisture barrier layers, have been incorporated into paperboard substrates used to form containers. However, issues remain with barrier performance, particularly after such paperboard barrier structures are shaped into containers and sealed.

[0005] Accordingly, those skilled in the art continue with research and development efforts in the field of paperboard barrier structures.

SUMMARY

[0006] In one embodiment, the disclosed paperboard barrier structure may include (1 ) a substrate having a first side and a second side; (2) a first sealing layer on the first side of the substrate; (3) a. laminated film layer on the second side of the substrate, the laminated film layer including a first film layer connected to a second film layer, wherein the first film layer and/or the second film layer includes a barrier coating, and wherein the barrier coating is positioned between the first and second film layers; and (4) a second sealing layer positioned over the laminated film layer such that the laminated film layer is positioned between the substrate and the second sealing layer.

[0007] In another embodiment, the disclosed container may include (A) a container body including an upper end and a. lower end, the container body being formed from a blank that includes (1 ) a substrate having a first side and a second side; (2) a first sealing layer on the first side of the substrate; (3 ) a laminated film layer on the second side of the substrate, the laminated film layer including a first film layer and a second film layer, wherein the first film layer and/or the second film layer includes a barrier coating, and wherein the barrier coating is positioned between the first and second film layers; and (4) a second sealing layer positioned over the laminated film layer such that the laminated film layer is positioned between the substrate and the second sealing layer; (B) a bottom sealed to the lower end of the container body; and (C) a lid sealed to the upper end of the container body.

[0008] Other embodiments of the disclosed paperboard barrier structure and associated container will become apparent from the following detailed description, the accompanying drawings and the appended claims.

BRIEF DE SCRIPTION OF THE DRAWINGS

[0009] Fig. 1 is a schematic cross-sectional view of one embodiment of the disclosed paperboard barrier structure;

[0010] Fig. 2 is a cross-sectional view of an example container formed from the paperboard barrier structure of Fig. 1 ;

[0011] Fig. 3 is a top p lan view of a blank for forming the container of Fig. 2;

[0012] Fig. 4A is cross-sectional view of a portion of the blank of Fig. 3, shown with a skived end;

[0013] Fig. 4B is cross-sectional view of the blank of Fig. 4A , shown with a skived and folded end; and [0014] Fig. 5 is a perspective view of a portion of the container body of the container of Fig. 2, showing the skived and folded end (Fig. 4B) of the blank (Fig. 3) overlapped by, and inside of, the opposite end of the blank.

DETAILED DESCRIPTION

[0015] Referring to Fig. 1, one embodiment of the disclosed paperboard barrier structure, generally designated 10, may include a substrate 12, a first sealing layer 14, a second sealing layer 16 and a laminated film layer 18. Additional layers, such as tie layers 20, 22, may be included in the disclosed paperboard barrier stmcture 10 without departing from the scope of the present disclosure.

[0016] The substrate 12 may be any paper or paperboard-based substrate. Examples of materials suitable for use as the substrate 12 of the disclosed paperboard barrier stmcture 10 include, but are not limited to, solid bleached sulfate board (SBS), coated natural kraft board (CNK board), solid unbleached sulfate board (SUS), coated recycled board (CRB), coated white lined chipboard (WLC), folding boxboard (FBB), cup stock paperboard.

[0017] The substrate 12 may have a basis weight of at least 85 pounds per 3000 ft². As one specific, non-limiting example, the substrate 12 may have a basis weight of about 100 to about 150 pounds per 3000 ft². As another specific, non-limiting example, the substrate 12 may have a basis weight of about 1 0 to about 180 pounds per 3000 ft². As yet another specific, non- limiting example, the substrate 12 may have a basis weight of about 180 to about 220 pounds per 3000 ft².

[0018] The caliper thickness of the substrate 12 may depend on various factors, such as the density of the substrate 12. For example, substrates 12 having caliper thicknesses of 10 points, 14, points, 16 points, 18 points and 20 points or more are contemplated. As used herein, 1 point equals 0.001 inches, which equals 25.4 micrometers (,um).

[0019] The substrate 12 may have a first side 24 and a second side 26. The first sealing layer 14 may be positioned on the first side 24 of the substrate 12. The laminated film layer 18 may be positioned on the second side 26 of the substrate 12. The second sealing layer 16 may be positioned over the laminated film layer 18 such that the laminated film layer 18 is positioned between the substrate 12 and the second sealing layer 16.

[0020] The first sealing layer 14 may be formed from various materials capable of being activated, such as with heat, ultrasonic energy, radiation or the like, to form a seal. As one specific, non-limiting example, the first sealing layer 14 may be formed from low density polyethylene (LDPE). As another specific, non-limiting example, the first sealing layer 14 may be formed from very low density polyethylene (VLDPE). Other examples of suitable sealing materials for forming the first sealing layer 14 include, but are not limited to, linear low density polyethylene (LLDPE), polyester, high density polyethylene (HDPE), ethylene- vinyl acetate copolymer (EVA), ethylene methyl acrylate (EMA) copolymer, 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

SURLY ^. Combinations of sealing materials may be used to form the first sealing layer 14.

[0021] The first sealing layer 14 may be applied to the first side 24 of the substrate 12 using any available technique. Non-limiting examples of suitable techniques for applying the first sealing layer 14 include, but are not limited to, extrusion coating, extrusion laminate, curtain coating, and adhesive lamination.

[0022] The laminated film layer 18 may include a first film layer 30 and a second film layer 32. in one construction, the first film layer 30 may include a first barrier coating 34 and the second film layer 32 may include a second barrier coating 36. In another construction, only one of the film layers (e.g., the film layer 30) may include a barrier coating (e.g., the first barrier coating 34).

[0023] The laminated film layer 18 may be formed by connecting the first film layer 30 to the second film layer 32 such that the barrier coatings 34, 36 are on the inside of the laminated film layer 18. Without being limited to any particular theory, when the laminated film layer 18 is constructed such that the barrier coatings 34, 36 are on the inside of the laminated film layer 18, the first and second film layers 30, 32 may protect the barrier coatings 34, 36 (e.g., the first and second film layers 30, 32 act as protective layers), thereby preserving (or at least inhibiting damage to) the barrier functionality (e.g., oxygen barrier functionality and/or water barrier functionality ) of the laminated film layer 18.

[0024] Various techniques may be used to connect the first film layer 30 to the second film layer 32. Selection of the connection technique may involve consideration of the composition of the barrier coatings 34, 36 and/or the composition of the first and second film layers 30, 32, In one specific implementation, the first film layer 30 may be connected to the second film layer 32 by adhesive lamination, wherein a laminating adhesive 38 may be positioned between the barrier coatings 34, 36 of the first and second film layers 30, 32. As one specific, non-limiting example, the laminating adhesive. 38 may be a urethane adhesive, such as a polyurethane adhesive,

[0025] Various polymeric films capable of receiving a barrier coating may be used as the first and second film layers 30, 32 of the laminated film layer 18,

[0026] In one implementation, the first and second film layers 30, 32 may be formed from biaxially-oriented polypropylene (BOPP). Each of the first and second BOPP film layers 30, 32 may be a single layer or a multi-layer structure. The cross-sectional thickness of each BOPP film layer 30, 32 may vary depending on the end application. For example, the cross-sectional thickness of each BOPP film layer 30, 32 may be at least 40 gauge, such 48 gauge, 60 gauge, 70 gauge, or 80 gauge.

[0027] In another implementation, the first and second film layers 30, 32 may be formed from polyethylene terephfhalate (PET). Each of the first and second PET film layers 30, 32 may be a single layer or a multi-layer structure. The cross-sectional thickness of each PET film layer 30, 32 may vary depending on the end application. For example, the cross-sectional thickness of each PET film layer 30, 32 may be at least 36 gauge, suc 48 gauge, 92 gauge or 142 gauge,

[0028] At this point, those skilled in the art will appreciate that the polymer compositions of the first and second film layers 30, 32 may be the same or different. For example, both the first and second film layers 30, 32 may be formed from the same material or the first film layer 30 may be formed from a different material than the second film layer 32.

[0029] Various barrier coatings 34, 36 may be applied to the first and/or second film layers 30, 32. In one expression, the barrier coatings 34, 36 may be metallization layers formed on the first and second film layers 30, 32. As one specific non-limiting example, the barrier coatings 34, 36 may be aluminum metallization layers. Therefore, the disclosed laminated film layer 18 may be formed by connecting a first metallized film layer (layers 30 and 34) to a second metallized film layer (layers 32 and 36), such that the metallization layers (layers 34, 36 are in the center of the layered film structure (the laminated film layer 18).

[0030] In another expression, the barrier coatings 34, 36 may be oxide coatings. As one specific non-limiting example, the oxide barrier coatings 34, 36 may include aluminum oxide. As another specific non-limiting example, the oxide barrier coatings 34, 36 may include silicon oxide. Therefore, the disclosed laminated film layer 18 may be formed by connecting a first oxide-coated film layer (layers 30 and 34) to a second oxide-coated film layer (layers 32 and 36), such that the oxide barrier coatings 34, 36 are in the center of the layered film structure (the laminated film layer 18).

[0031] At this point, those skilled in the art will appreciate that the compositions of the first and second barrier coatings 34, 36 may be the same or different. As one example, both the first and second barrier coatings 34, 36 may be formed from the same material (e.g., aluminum). As another example, the first and second barrier coatings 34, 36 may be formed from different materials (e.g., aluminum metal for barrier coating 34 and aluminum oxide for barrier coating 36).

[0032] Suitable films (film layers 30, 32) with the barrier coating (34, 36) pre-applied are commercially available from a variety of sources. For example, E. I. du Pont de Nemours and Company may supply aluminum metallized MYLAR*^' film, two layers of which may be connected (metallization-to-metallization), such as by way of adhesive lamination, to form the disclosed laminated film layer 18.

[0033] The laminated film layer 18 may be applied to the second side 26 of the substrate 12. A tie layer 20 may connect the laminated film layer 18 to the substrate 12. In one variation, the tie layer 20 may be formed from a sealing material, such as a polyolefin (e.g., LDPE), that is activated, such as with heat, ultrasonic energy, radiation or the like, to connect the laminated film layer 18 to the substrate 12, In another variation, the tie layer 20 may be a solvent-based adhesive, such as an organic solvent-based adhesive or an aqueous solvent-based adhesive.

[0034] The second sealing layer 16 may be positioned over the laminated film layer 18 such that the laminated film layer 18 is positioned between the substrate 12 and the second sealing layer 16. The second sealing layer 16 may be formed from various materials capable of being activated, such as with heat, ultrasonic energy, radiation or the like, to form a seal. As one specific, non-limiting example, the second sealing layer 16 may be formed from low density polyethylene (LDPE). As another specific, non-limiting example, the second sealing layer 16 may be formed from very low density polyethylene (VLDPE). Other examples of suitable sealing materials for forming the second sealing layer 16 include, but are not limited to, polyester, linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene -vinyl acetate copolymer (EVA), ethyiene methyl acrylate (EMA) copolymer, ionomer polymers such as poly(eihylene-co-methacrylic acid) (EMAA) copolymer. Combinations of sealing materials may be used to form the second sealing layer 16. [0035] The second sealing layer 16 may be applied to the laminated film layer 18 using any available technique. Non-limiting examples of suitable techniques for applying the second sealing layer 16 include, but are not limited to, extrusion coating, extrusion laminate, curtain coating, and adhesive lamination.

[0036] Optionally, a tie layer 22 may be positioned between the laminated film layer 18 and the second sealing layer 16. The composition of the tie layer 2,2 may be selected to enhance the bond between the laminated film layer 18 and the second sealing layer 16. For example, the tie layer 22 may be formed from a polymeric material (e.g., linear low density polyethylene) that has a higher molecular weight than the material (e.g., very low density polyethylene) used to form the second sealant layer 16.

[0037] As one very specific, non-limiting example, the disclosed paperboard barrier structure 10 may be constructed as follows: low density polyethylene (first sealing layer 14); SBS paperboard (substrate 12); low density polyethylene (tie layer 20); biaxially-oriented

polypropylene (first film layer 30); aluminum metallization (barrier coating 34 on layer 30); urethane (laminating adhesive 38); aluminum metallization (barrier coating 36 on layer 32); biaxially-oriented polypropylene (second film layer 32); linear low density polyethylene (tie layer 22); and very low density polyethylene (second sealing layer 16).

[0038] Referring to Fig. 2, also disclosed is a container, generally designated 100, formed from the paperboard barrier structure 10 shown in Fig. 1. The container 100 may include a container body 102, a bottom 104 and a lid 106.

[0039] The container body 102 may be formed by die-cutting a sheet of the disclosed paperboard barrier structure 10 (Fig. 1) to form a blank 108, shown in Fig. 3, having the desired silhouette (e.g., trapezoidal or rectangular). The blank 108 may include a first longitudinal end 1 10 and a second longitudinal end 112.

[0040] As shown in Fig. 4 A, the first longitudinal end 1 10 of the blank 08 may be skived to a predetermined thickness T for a. predetermined width W. The resulting skived end 1 10 of the blank 108 may be treated with heat, then folded and sealed over the blank 108 (onto the first sealing layer 14) to provide a folded first longitudinal end 1 10 ^', as shown in Fig. 4B.

[0041] As shown in FIG. 5, the container body 102 may be formed by overlapping both longitudinal ends 1 10', 112 of the blank 108 to form an overlapped seam 1 14 in which the folded first longitudinal end 1 10 ^' is positioned inside the second longitudinal end 1 12. The seam 1 14 may be sealed by connecting the second sealing layer 16 (Fig. 1 ) of the folded first longitudinal end 1 10 ^' to the second sealing layer 16 (Fig. 1) of the second longitudinal end 112.

[0042] Referring back to Fig. 2, the lid 106 may also be form from the disclosed paperboard barrier structure 10 (Fig. 1 ) or a similar structure (e.g., the same as the paperboard barrier structure 10, but without the first sealing layer 14), though use of other lid structures (e.g., films, plastic lids) is also contemplated.

[0043] Various techniques may be used to seal (e.g., hermetically seal) the lid 106 to the body component 102. As one example, the upper end 122 of the container body 102 may be rolled over to form a bead or flange 1 16 and the lid 106 may be hermetically sealed to the flange 1 16. Other examples of suitable techniques for sealing the lid 106 to the container body 102 include, but are not limited to, (1 ) hermetically sealing the top with a plastic rim; (2) a rolled rim 116 with a sealing bead dropped at the step-down area (proximate the seam 1 14) of the rolled rim 1 16; (3) a sealing bead added to the entire top rim 116 before lidding; (4) a lidding material with a heavy sealing layer, such as a lidding films commonly used for sealing barrier trays; and (5) a higher sealing pressure to press down lidding material to flatten the rim 116 for maximum seal.

[0044] The bottom 104 may be formed from the disclosed paperboard barrier structure 10 (Fig. 1) or a similar structure. However, use of other bottom structures (e.g. , films, plastic lids, metal lids) is also contemplated

[0045] Various techniques may be used to seal (e.g., hermetically seal) the bottom 104 to the body component 102. As one example, the lower end 124 of the container body 102 may be shaped to form a circumferential recess 120. The bottom 104 may be placed into the recess 120 and heat-sealed to the container body 102. Other examples of suitable techniques for sealing the bottom 104 to the container body 102 include, but not limited to, hot air heat seal and ultrasound sealing.

[0046] Although various embodiments of the disclosed paperboard barrier structure and associated container 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.

[0047] What is claimed is:

Claims

1. A container comprising

a container body including an upper end and a lower end, said container body being formed from a blank comprising:

a substrate having a first side and a second side;

a first sealing layer on said first side of said substrate;

a laminated film layer on said second side of said substrate, said laminated film layer comprising a first film layer connected to a second film layer, wherein at least one of said first film layer and said second film layer comprises a barrier coating, and wherein said barrier coating is positioned between said first film layer and said second film layer; and

a second sealing layer positioned over said laminated film layer such that said laminated film layer is positioned between said substrate and said second sealing layer.

2. The container of Claim 1 wherein said blank comprises a first longitudinal end and a second longitudinal end, and wherein said container body comprises an overlapped seam comprising said first longitudinal end positioned inside said second longitudinal end.

3. The container of Claim 2 wherein said first longitudinal end is skived to a predetermined thickness for a predetermined width, and wherein said skived portion is folded over onto said blank and sealed to said first sealing layer to form a folded first longitudinal end.

4. The container of Claim 1 wherein said substrate comprises paperboard.

5. The container of Claim 1 wherein said substrate comprises solid bleached sulfate paperboard having a basis weight of at least 85 pounds per 3000 square feet.

6. The container of Claim 1 wherein said first sealing layer comprises a material selected from the group consisting of polyester, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), ethylene methyl acrylate (EMA), ionomer polymers, and combinations thereof.

7. The container of Claim 1 wherein said barrier coating comprises a metallization layer.

8. The container of Claim 7 wherein said metallization layer comprises aluminum.

9. The container of Claim 1 wherein said barrier coating comprises an oxide coating.

10. The container of Claim 9 wherein said oxide coating comprises at least one of aluminum oxide and silicon oxide.

1 1. The container of Claim 1 wherein said first film layer comprises at least one of biaxially- oriented polypropylene and polyethylene terephthalate.

12. The container of Claim 1 1 wherein said second film layer comprises at least one of biaxially-oriented polypropylene and polyethylene terephthalate.

13. The container of Claim 1 wherein said first film layer comprises a first barrier coating and said second film layer comprises a second barrier coating, and wherein both said first barrier coating and said second barrier coating are positioned between said first film layer and said second film layer.

14. The container of Claim 1 wherein said first film layer is connected to said second film layer with a laminating adhesive.

15. The container of Claim 14 wherein said laminating adhesive comprises a urethane.

16. The container of Claim 1 further comprising a tie layer between said laminated film layer and said substrate.

17. The container of Claim 1 further comprising a tie layer between said laminated film layer and said second sealing layer.

18. The container of Claim 1 further comprising a bottom sealed to said lower end.

19. The container of Claim 1 further comprising a lid sealed to said upper end.

20. A paperboard barrier structure comprising:

a paperboard substrate having a first side and a second side;

a first sealing layer on said first side of said substrate;

a laminated film layer on said second side of said substrate, said laminated film layer comprising: a first film layer; and

a second film layer connected to said first film layer,

wherein at least one of said first film layer and said second film layer comprises a barrier coating, and

wherein said barrier coating is positioned between said first film layer and said second film layer; and