Paper packaging with a film barrier

Abstract

The present disclosure relates to paper-based packaging films having a structure comprising a paper component, a 2 to 10 micrometer thick polymer film coated with a barrier material, and a patterned sealable material. The structure can be readily recycled through repulping while retaining high performance packaging features, including high barrier, three-phase point caulking, and high run speeds on packaging equipment. The present disclosure also describes sealed packages having paper-based packaging films.

Description

Technical Field

[0001] This disclosure relates to paper-based packaging film structures. The structures described herein include barrier materials and patterned sealable materials. Background Technology

[0002] Improving the recyclability of paper-based packaging films becomes challenging when attempting to create packaging films with enhanced barrier properties and an airtight seal at the triple point region. Traditionally, improvements in barrier properties and sealability of paper-based packaging films have been achieved by forming multilayer films. Multilayer films contain multiple layers specifically designed to form the barrier layer and additional layers providing enhanced sealing properties. As performance requirements increase, the number of layers or layer thickness in multilayer films increases, which is detrimental to the recyclability of the structure because the paper content decreases by a percentage.

[0003] Typically, when high performance is desired in paper-based packaging films, a relatively large amount of additional non-paper material is added to the film structure to meet the requirements for high barrier and airtight sealing at the triple point region. To maintain the recyclability of the paper-based packaging film, the thickness and / or weight of the paper components are increased to achieve the paper content required for the indicated recyclability of the packaging material. The problems with this additional paper material are: 1) it is wasteful to add, and 2) the additional volume of the packaging film causes processing problems on packaging forming equipment. Increased film thickness and stiffness generally lead to slower linear speeds because the film is more difficult to pull through the forming collar. The packaging film may also be more difficult to seal because the added paper weight tends to absorb heat from the sealing strip and / or hinder the application of evenly distributed pressure. Summary of the Invention

[0004] This paper discloses a flexible packaging film with high barrier properties and excellent sealing performance, while maintaining recyclability during paper recycling. The packaging film includes paper components and incorporates a minimal amount of non-fibrous materials (i.e., a minimal amount of non-paper materials) to achieve high barrier properties and excellent sealing performance.

[0005] This article discloses a paper-based packaging film having a paper component, a polymer film (coated with a barrier material) comprising a thickness ranging from 2 μm to 10 μm, and a patterned sealable material. The polymer film is positioned between the paper component and the patterned sealable material, the barrier material is positioned between the polymer film and the paper component, and the overall composition of the paper-based packaging film may be greater than or equal to 80%, 85%, 90%, or 95% by weight of the paper component.

[0006] In some embodiments of this paper-based packaging film, the barrier material comprises a metal, a metal oxide, or an inorganic oxide. In some embodiments, the barrier material can be attached to the paper component using an adhesive.

[0007] Some embodiments of this paper-based packaging film can be described as having an outer surface and an inner surface, a paper component, a polymer film comprising a thickness ranging from 2 μm to 10 μm (the polymer film being coated with a barrier material comprising a metal, metal oxide, or inorganic oxide), and a sealable material. In one or more embodiments, the outer surface comprises the paper component, the inner surface comprises each of the polymer film and the sealable material, and the barrier material is positioned between the polymer film and the paper component. The paper-based packaging film may have a total composition having a paper component comprising greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, or greater than or equal to 95% by weight.

[0008] The paper-based packaging film may incorporate a heat-sealable sealable material, or the sealable material may be a pressure-sensitive cold-sealable component. The sealable material may have a concentration of 1 g / m³. 2 With 10g / m 2 The basis weight between. This sealable material can have 2g / m³. 2 With 6g / m 2 The base weight between.

[0009] Some embodiments of the paper-based packaging film include a polymer film, such as a BOPP film, a BOPET film, or an OPLA film. Some embodiments of the paper-based packaging film also include an adhesive layer for attaching paper components to the polymer film. This adhesive layer may include a water-sensitive material.

[0010] Further embodiments disclosed herein relate to sealed packages formed from or including paper-based packaging films as described herein. The sealed package may have a packaging construction comprising one or more triple-point sealing regions, each of which includes a sealable material. It has been advantageously found that the triple-point sealing regions do not emit bubbles when leak tested according to ASTM D3078 or similar test methods. In some embodiments, the packaging construction is a flow wrap or pouch, and the basis weight of the paper-based packaging film is approximately 35 g / m³. 2 Approximately 80g / m 2 Within the range. In other embodiments, the packaging structure includes gussets and the basis weight of the paper-based packaging film is approximately 60 g / m³. 2 Approximately 140g / m 2 Within the range. Attached Figure Description

[0011] This disclosure can be more fully understood by taking into account the following detailed description of various embodiments of the present disclosure in conjunction with the accompanying drawings, in which:

[0012] Figure 1This is an example of a cross-sectional view of a paper-based packaging film.

[0013] Figure 2 This is another embodiment of a cross-sectional view of a paper-based packaging film.

[0014] Figure 3 This is a plan view of the inner surface of an embodiment of a paper-based packaging film.

[0015] Figure 4 This is a perspective view of an embodiment of a sealed package including a paper-based packaging film.

[0016] Figure 5 This is a perspective view of another embodiment of a sealed package including a paper-based packaging film.

[0017] Figure 6 It is a cross-sectional view of the end seal of the sealed package, including the three-point sealing area, and

[0018] Figure 7 It is a cross-sectional view of the end seal of a sealed package, including a three-point sealing area with gaps.

[0019] The accompanying drawings are not necessarily drawn to scale. The same reference numerals used in the drawings refer to the same parts. However, it should be understood that the use of reference numerals to refer to parts in each drawing is not intended to limit the parts to be labeled with the same reference numerals in another drawing.

[0020] The accompanying drawings illustrate some, but not all, embodiments. The elements depicted in the drawings are illustrative and not necessarily drawn to scale, and the same (or similar) reference numerals represent the same (or similar) features throughout the drawings. Detailed Implementation

[0021] This paper presents a paper-based packaging film that overcomes the shortcomings of previously offered films. The disclosed paper-based packaging film is uniquely designed to provide a key combination of 1) recyclability (high paper content), 2) ease of packaging conversion, 3) high barrier properties, and 4) an airtight seal at the triple point region. High barrier properties are achieved through the use of a thin polymer film coated with a barrier material. An airtight seal is achieved through localized or patterned sealing materials, allowing for minimal material usage while maintaining high performance. Furthermore, this unique combination of layers and materials allows for a high overall paper content and low thickness, resulting in excellent operational performance (i.e., high operating speeds) on packaging equipment.

[0022] This article also provides an hermetically sealed package that includes a triple point region within the seal, comprising a paper-based packaging film with a high paper content. The design of this paper-based packaging film allows for hermetically sealed triple point regions of seals in commercial packaging equipment while retaining a recyclable packaging structure with minimal thickness.

[0023] The paper-based packaging film described herein includes paper components, polymer films, barrier materials, and patterned sealable materials. The paper-based packaging film may include additional layers. The combination of these materials can be described as a multilayer film (e.g., a structure or laminate). As used herein, the term "layer" refers to a building block of the film. A layer is a structure of a single material type or a homogeneous blend of materials. A layer can be a single polymer, a blend of materials within a single polymer type, or a blend of various polymers. Layers may contain metallic materials and may have additives. Layers may be continuous with the film or may be discontinuous or patterned. Both layers and the film have a relatively small thickness (z-direction) compared to their respective length and width (xy direction).

[0024] All layers and films described herein have two primary surfaces opposite each other, defined by an xy plane. As used herein, the term "outer layer" refers to one or more layers of the film on either primary surface, i.e., layers not between two other layers of the film. The film has an outer surface that becomes the exterior of the packaging using the film. When packaging is formed, the outer surface of the film is exposed to the environment. The film has an inner surface that becomes the interior of the packaging using the film. When packaging is formed, this inner surface is used to form a seal and is exposed to the packaged product.

[0025] As used herein, the term “adjacent” means that articles, such as layers of film, are close to each other with or without an intermediate material such as an adhesive. As used herein, the terms “directly adjacent” or “directly in contact” mean that articles are in contact with each other without an intermediate material.

[0026] Figure 1A cross-sectional view of an embodiment of the paper-based packaging film 100 is shown. In some embodiments, a paper component 110 forms an outer layer positioned on the outer surface 102 of the paper-based packaging film 100. In some embodiments, the paper component 110 is adjacent to a barrier material 130, which is adjacent to a polymer film 120. In some embodiments, the barrier material 130 is positioned on the surface of the polymer film 120 and between the polymer film 120 and the paper component 110. In some embodiments, a patterned sealable material 140 is positioned adjacent to the polymer film 120 and on the surface of the polymer film 120 opposite to the barrier material 130. The inner surface 104 of the paper-based packaging film 100 is formed by both the polymer film 120 and the patterned sealable material 140. In the regions of the patterned sealable material 140, the inner surface 104 is the sealable material, and in other regions of the inner surface 104, it is the polymer film 120.

[0027] Figure 2 A cross-sectional view of another embodiment of the paper-based packaging film 200 is shown. In some embodiments, a paper component 210 forms an outer layer positioned at the outer surface 202 of the paper-based packaging film 200. In some embodiments, the paper component 210 is adjacent to a barrier material 230, which in turn is adjacent to a polymer film 220. In some embodiments, the paper component 210 and the barrier material 230 are bonded to each other by an adhesive layer 250. In some embodiments, the barrier material 230 is located on the surface of the polymer film 220 and positioned between the polymer film 220 and the paper component 210. In some embodiments, a patterned sealable material 240 is positioned adjacent to the polymer film 220 and on the surface of the polymer film 220 opposite to the barrier material 230. The inner surface 204 of the paper-based packaging film 200 is formed by both the polymer film 220 and the patterned sealable material 240. In the regions of the patterned sealable material 240, the inner surface 204 is the sealable material, and in other regions of the inner surface 204, it is the polymer film 220.

[0028] Figure 3 A plan view of the inner surface 304 of an embodiment of a paper-based packaging film 300 is shown, which can be used to produce flow wrap-type packaging, such as... Figure 4 The packaging 10 shown. In some embodiments, the inner surface 304 includes a sealable material 340 located in an area where the sealable material 340 is patterned (the application pattern shown in the hash mark area). The inner surface 304 also includes a polymer film 320 located in an area not covered by the sealable material 340. The bottom corners of the paper-based packaging film 300 are folded up to expose the paper component 310 on the outer surface 302 of the paper-based packaging film 300.

[0029] See you again Figure 1-3The paper-based packaging film disclosed herein includes a paper component. In one or more embodiments, the paper component is an outer layer of the paper-based packaging film, which is positioned on the outer surface of the paper-based packaging film. In some embodiments, the paper component includes additional components adjacent to or located on the outer surface of the paper component (such as ink or topcoat). The paper component may have a basis weight of 30 g / m³. 2 Up to 360g / m 2 30g / m 2 Up to 100g / m 2 , more preferably 30g / m 2 Up to 70g / m 2 Any type of paper. Because additional components are minimized, the weight of the paper components can be reduced while retaining easy recyclability. Examples of paper components that can be used in paper-based packaging films include, but are not limited to, kraft paper, parchment paper, and bleached paper. The paper components can be coated (i.e., clay-coated) or uncoated. Examples of commonly used papers in packaging that will be acceptable in the paper-based packaging films described herein include machine-varnished bleached kraft paper (MGBK), cellophane, single-sided clay-coated paper (C1S), and double-sided clay-coated paper (C2S), but less common papers that provide improved mechanical or barrier properties through the use of specialty fibers or additives may also be part of the paper-based packaging films described in this application.

[0030] In some embodiments, the paper-based packaging film disclosed herein comprises a polymer film. Advantageously, the polymer film is very thin. The polymer film may have a thickness greater than or equal to 2 micrometers, greater than or equal to 3 micrometers, or greater than or equal to 4 micrometers. The polymer film may have a thickness less than or equal to 10 micrometers, less than or equal to 9 micrometers, or less than or equal to 8 micrometers. For example, the polymer film may have a thickness in the range of 2 to 10 micrometers, or in the range of 2 to 8 micrometers. Preferably, the polymer film has a thickness in the range of 4 to 8 micrometers.

[0031] The polymer film preferably comprises an oriented film, such as biaxially oriented polypropylene (BOPP), biaxially oriented polyester (BOPET), uniaxially oriented polyethylene (MDOPE), biaxially oriented polyamide (BOPA), or oriented polylactic acid (OPLA). The polymer film may consist of a single layer or multiple layers.

[0032] The polymer film can be an unoriented material, such as, but not limited to, unoriented PLA.

[0033] In some embodiments, the polymer film is coated with a barrier material. The barrier material may be applied directly to the polymer film, or a primer layer may be present between the barrier material and the polymer film. In some embodiments, the polymer film includes a topcoat located between the barrier material and the paper component. The topcoat may be applied directly to the barrier material. In some embodiments, the barrier material is positioned between the polymer film and the paper component. The barrier material reduces the permeation of oxygen, moisture, or both.

[0034] In some embodiments, the polymer film and barrier material of the paper-based packaging film each extend together with the paper component. In some embodiments, the barrier material is positioned between the paper component and the polymer film. The barrier material may be polymeric, such as polyamide, ethylene-vinyl alcohol copolymer, or polyvinyl alcohol copolymer. The barrier material may be a thin-layer deposition of a metal, such as aluminum. The barrier material may be a transparent metal oxide coating or an inorganic oxide coating, such as alumina (AlOx) or silicon oxide (SiOx). The barrier material may be multilayered and contain different barrier material layers. The barrier material may be a blend of multiple barrier materials.

[0035] The inventors have produced and discovered barrier materials, including SiOx, AlOx, and aluminum, that can be used in paper-based packaging films. These barrier materials are applied to polymer films via a vapor deposition process, and the thickness of the barrier materials is negligible relative to the packaging film (i.e., less than 1 micrometer or less than 0.5 micrometers). These barrier materials have been coated onto polymer films of BOPET, BOPP, MDOPE, MDOPE, OPA, and amorphous PA.

[0036] The inventors have produced and discovered combinations of polymer films and barrier materials that can be used in paper-based packaging films, including SiOx-coated OPET, SiOx-coated BOPP, AlOx-coated OPET, AlOx-coated BOPP, aluminum-coated OPET, and aluminum-coated BOPP.

[0037] Paper-based packaging films containing barrier materials coated on a polymer film have a thickness of 5 cm or less. 3 / m 2 / day, less than or equal to 1cm 3 / m 2 / day or less than or equal to 0.5cm 3 / m 2 The average oxygen permeability (OTR) value per day is measured according to ASTM F1927 under conditions of 1 atmosphere, 23°C, and 50% RH. In some embodiments, the paper-based packaging film containing a barrier material coated on a polymer film has a value of less than or equal to 1 g / m³. 2 / day, or less than or equal to 0.3g / m 2 The average moisture transmittance (MVTR) value per day was measured according to ASTM F1249 under conditions of 1 atmosphere, 38°C, and 90% RH. An overview of the examples of the invention and the measured barrier properties can be found in Table 3.

[0038] The paper-based packaging film also includes a patterned sealable material as an outer layer on the inner surface. As used herein, the term "patterned" means that the sealable material layer is discontinuous with the paper-based packaging film. The sealable material is discontinuous with the polymer film on which it is applied. The sealable material can be applied to the area of ​​the paper-based packaging film involved in sealing and closing the package. The sealable material can be applied over a surface portion of the polymer film of 5% or more, 10% or more, or 15% or more. The sealable material can be applied over a surface portion of the polymer film of 30% or less, 25% or less, or 20% or less. As a result, the inner surface of the paper-based packaging film is partly the surface of the polymer film and partly the sealable material. For example, the inner surface of the paper-based film can be approximately 80% polymer film and 20% sealable material. The inner surface can consist substantially of the polymer film and the sealable material or consist of both the polymer film and the sealable material.

[0039] The sealable material of a paper-based packaging film may have a composition that allows for the formation of a heat-sealed joint, thereby creating an airtight package. As used herein, the terms “heat-sealed,” “heat-sealable,” or “heat-sealed” refer to two or more surfaces that are already bonded together, or can be bonded together by applying both heat and pressure. Heat sealing is a known and commonly used process for manufacturing packaging and is well known to those skilled in the art. Without being bound by theory, during heat sealing, the sealing layer softens due to the application of heat, thereby allowing the formation of a heat-sealed bond. Since heat must be driven through the entire paper-based packaging film to raise the temperature of the sealable material, and paper components often absorb a significant amount of heat, it is advantageous if the heat-sealable material softens and seals at a relatively low temperature. A lower seal initiation temperature (SIT) allows for faster packaging line speeds. For example, some embodiments of paper-based packaging films may include heat-sealable materials exhibiting a SIT of less than or equal to 110°C, less than or equal to 100°C, or less than or equal to 90°C. Possible heat-sealing materials may include, but are not limited to, acrylate copolymers, PET, PE, PP, or hot melt adhesives (wax-based).

[0040] The sealable material can alternatively be a pressure-sensitive cold seal. This embodiment of paper-based packaging film is advantageous because the formation of the package does not require heat. Without being bound by theory, pressure-sensitive cold seals may be advantageous for packaging heat-sensitive products such as ice cream or chocolate. Embodiments of paper-based packaging film may include pressure-sensitive cold seal systems, including but not limited to natural or synthetic polyisoprene latex or styrene-butadiene copolymer latex. The cold seal material may include blends containing acrylates and / or tackifiers.

[0041] In some embodiments, the sealable material acts as a sealant. In some embodiments, the sealable material flows into the gap in the triple point region (described below) under sealing conditions. Not bound by theory, the appropriate ability to seal the triple point can be produced by a combination of material properties, coating weight, and sealing conditions. It is believed that having a relatively thick sealant in the heat-sealed region significantly increases the possibility of reducing the size of the triple point region of the seal. In one or more preferred embodiments, the sealable material is not oriented.

[0042] Sealing materials are applied to allow for hermetic seals, even in challenging applications such as triple point region sealing. In some embodiments, the sealing material may be applied at a thickness greater than or equal to 1 g / m³. 2 or greater than or equal to 3g / m 2 The base weight is applied. In other embodiments, the sealable material can be applied at a rate of less than or equal to 8 g / m³. 2 Less than or equal to 9g / m 2 or less than or equal to 10g / m 2 The basis weight is applied. For example, a sealable material may have a basis weight of about 1 g / m³. 2 Approximately 10g / m 2 Within the range, or at approximately 3g / m 2 Approximately 9g / m 2 Basis weight within the range.

[0043] As used herein, the term "basis weight" refers to the amount of material present by weight in a predetermined area of ​​a film or layer. Typically, the defined area is one square meter, but any area can be used. This area is defined along the length-width (i.e., the xy direction) of the film or layer. A material of a given thickness (z direction) and density has a specific weight when covering the defined area (i.e., one square meter). Basis weight is a common method of measuring the weight of paper because the density of paper varies greatly. In other words, measuring paper by thickness can be difficult. Materials applied in discontinuous layers (such as patterned sealable materials) can be defined by basis weight. In the case of patterns, basis weight refers to the amount of material present by weight when covering a defined area. Using basis weight to measure the weight of materials such as paper and patterned materials is common in the film conversion industry.

[0044] Paper-based packaging films may include an adhesive layer that bonds paper components to a barrier material. The adhesive can be in direct contact with the paper. The adhesive can be in direct contact with the barrier material. The adhesive can be applied by any known web-to-web lamination method (e.g., dry bonding lamination, wet bonding lamination, or hot lamination). The adhesive may have a strength between 0.5 g / m³. 2 and 4.0g / m 2 The dry basis weight between (i.e., after solvent removal).

[0045] The embodiments disclosed herein advantageously provide a paper-based packaging film comprising an adhesive layer having a water-sensitive adhesive. As used herein, the term "water-sensitive" means that upon prolonged exposure to or immersion in liquid water, the adhesive loses its adhesive and / or cohesive properties, thereby allowing the paper component to delaminate (i.e., separate) from the remainder of the paper-based packaging film structure during repulping. Examples of materials that may be used within the adhesive layer between the paper component and the barrier layer include, but are not limited to, latex / casein blends, starch, sugar derivatives, cellulose, amino resins, (poly)acrylates, polyvinyl alcohol (PVOH), polyvinyl acetate, polyacrylic acid, maleic acid-modified ethylene copolymers, methylcellulose, carboxymethylcellulose, carboxyl-functionalized polyesters, polyethylene succinate, polybutylene succinate, ionomers, or hydrophilic polyurethanes.

[0046] As mentioned earlier, the packaging film may also include ink positioned on the outer surface of the paper-based packaging film. The type and amount of ink may vary within the limits of local paper recycling guidelines.

[0047] As described herein, the “total composition” of a paper-based packaging film refers to all materials contained therein. The total composition of a paper-based packaging film may include paper components comprising 80% or more, 85% or more, 90% or more, or 95% or more by weight. Alternatively, the total composition of a paper-based packaging film may include paper components comprising less than or equal to 99% or more, 98% or more, 97% or more, or 96% or more by weight. For example, a paper-based packaging film may contain paper components comprising approximately 85% to approximately 98% of the total composition by weight.

[0048] In some embodiments, when a pressure-sensitive cold-seal material is used as the sealable material, a release lacquer can be added to the outer surface of the paper component (i.e., the outer surface of the paper-based packaging film). When the film is in roll form, the lacquer prevents the cold-seal material from adhering to the paper component. In some embodiments, the release lacquer comprises a polyamide matrix having one or more wax additives. Water-based release lacquers are believed to be advantageous for peeling coatings and inks from the non-sealed side of the structure.

[0049] Paper-based packaging films can be advantageously used to form hermetically sealed packages. These packages may include a triple-point region. As used herein, a "triple-point region" is a construction of the paper-based packaging film in its sealed area, comprising a junction where three or more inner surfaces of the paper-based packaging film intersect at a single point. It is believed that triple-point regions are prone to non-hermetically leaking because completely sealing this type of region becomes more difficult. Reference Figure 4 , 5 Sections 6 and 7 discuss the challenges associated with the sealed triple point region.

[0050] Figure 4 A perspective view is shown of an airtight package 10 formed from a paper-based packaging film 400, including one or more triple point regions 15, which may have the same characteristics as... Figures 1-3 The paper-based packaging films 100, 200, and 300 shown have the same characteristics. Paper-based packaging film 400 has been run through a flow wrapping machine to seal the film 400 around the product (not shown). Paper-based packaging film 400 is oriented such that its outer surface (i.e., the side of the paper component) is on the outside of the package 10 and is visible to the consumer. Similarly, the inner surface of paper-based packaging film 400 (i.e., the side of the polymer film and the sealable material) is on the inside of the package 10 (not shown) and exposed to the packaged product. The sealable material is joined to hermetically seal the product therein. Package 10 includes finned seals 12 along the length of the package and two end seals 14. Figure 4 In the illustrated embodiment, the package 10 has two triple point regions 15 located at the overlapping area of ​​the fin seal 12 and the end seal 14.

[0051] When the paper-based packaging film 400 is used in the construction of flow parcels or pouches, the paper-based packaging film 400 can have a strength of approximately 35 g / m³. 2 Approximately 80g / m 2 Basis weight within the range. Not bound by theory, approximately 35 g / m³. 2 Approximately 80g / m 2 The basis weight range reflects the structure that can have high paper content and good packaging conversion. In other words, the paper-based packaging film 400 has characteristics such as low stiffness and high heat transfer to operate well on high-speed packaging equipment.

[0052] Figure 6 and Figure 7 A cross-sectional view of the triple point region 15 of the hermetically sealed package 10 is shown. The finned seal 12 points upward and the end seal 14 is horizontal. Figure 6 and Figure 7In the illustrated embodiment, a triple point region 15 is formed when the paper-based packaging film 400 located on the right side of the finned seal 12, the paper-based packaging film 400 located on the left side of the finned seal 12, and the paper-based packaging film 400 located at the bottom of the end seal 14 intersect. In the case of a flowable package type packaging, each of the three paper-based packaging films 400 forming the triple point region 15 includes the same paper-based packaging film 400 folded onto itself. Figure 6 and Figure 7 Specifically, the sealable material 440 of the paper-based packaging film 400, which is now sealed together with the others, is shown. After the package 10 is sealed, the sealable material flows together and forms a single layer, as shown. Figure 6 and Figure 7 As shown.

[0053] During the automated packaging process, the triple point region 15 may be difficult to seal airtightly, effectively, and consistently. As the film is folded into the triple point region, variations in film thickness cause uneven pressure and / or temperature at the transition point. If the sealing pressure and / or temperature is insufficient for a seal, or if the type or thickness of the sealable material is unsuitable, gaps may remain between the films in the triple point region 15. These gaps prevent airtightness. Figure 7 An example of the three-phase point region gap 16 is shown. Figure 6 The triple point region 15, which has been successfully hermetically sealed without gaps, is shown.

[0054] Achieving a three-point seal on a paper-based packaging film can be very difficult. If the sealable material is heat-sealable, the paper component often provides significant insulation, thus hindering good heat transfer to the sealable material. When heat transfer is insufficient, the flow of the sealable material is inadequate to fill the spaces where the films intersect, leaving gaps. Additionally, the paper-containing structure may have greater stiffness, preventing sufficient pressure to push the sealant together at the three-point. This stiffness of the film can cause sealing problems with heat-sealable materials or pressure-sensitive cold seals.

[0055] The paper-based packaging film disclosed in this paper provides an excellent film for packaging including triple point regions. This film can be recycled in paper-based recycle streams (i.e., high paper content) without significant volumetric and / or stiffness issues. Large volume and / or stiffness can hinder effective triple point sealing. Furthermore, the use of patterned sealable materials provides significantly easier triple point sealing because the sealable material is concentrated where it is needed in the sealing area, without significantly affecting the non-paper content of the packaging film.

[0056] Figure 5 Another embodiment of a package 20 including one or more triple point regions 25 is shown. Figure 5In the illustrated embodiment, package 20 is a flat-bottomed bag with terminating side gussets. The side gussets terminate at a triple point region 25, and the films intersecting at the triple point include a front panel, a rear panel, and a side gusset panel panel. Additionally, the triple point region 25 is located at each corner of the bottom, where the bottom panel intersects with the side panels and the front / rear panels. Each of these panels is made of paper-based packaging film 500. Many other packaging forms include triple point regions that are conceivable to those skilled in the art.

[0057] When paper-based packaging film is used in packaging constructions that include gusseted panels, the film can have a strength of approximately 60 g / m³. 2 Approximately 140g / m 2 Basis weight within the range. Approximately 60 g / m³ 2 Approximately 140g / m 2 The basis weight range reflects a paper-based packaging film structure that can have high paper content and good packaging conversion rate. In other words, the film has properties such as moderate stiffness and high heat transfer for good operation on high-speed packaging equipment.

[0058] The effectiveness of a triple point seal (i.e., the presence of a gap) can be determined through packaging leakage testing, such as the tests outlined in ASTM D3078, "Standard Test Method for Determination of Leaks in Flexible Packaging by Bubble Emission." As noted in this test method, this test may not analyze small openings in the seal, but it is designed to determine the presence of leaks harmful to a particular product. For testing packaging formed from paper-based packaging film with a seal including the triple point region, water can be used as the immersion fluid and a full vacuum level should be maintained for 30 seconds. The full vacuum level depends on the packaging construction and should be selected such that the packaging is inflated, forcing any headspace gas inside the packaging to vent through the small leak at the triple point region. However, care should be taken not to increase the pressure to a level that would damage the seal and packaging material or otherwise harm it.

[0059] A revised version of the ASTM D3078 test includes applying pressure inside the packaging. This can be done using a needle and a diaphragm. The diaphragm is placed on the packaging, and then punctured with a needle. Air can be forced into the packaging at a controlled rate through the needle, increasing the internal pressure by 0.05 bar every 3 seconds. The airtightness of the pack can be assessed by carefully increasing the air rate and monitoring the pressure. The packaging is also tested underwater, and the pressure required for bubbles to form from the triple point region is recorded.

[0060] Other tests that can be used to detect inadequate sealing in the triple point region include dye (rhodamine) penetration testing or analysis by microscopy. Microscopic techniques can be used to locate the gap 16 within the triple point region 15, for example... Figure 7 The gap 16 is shown in the diagram. It is believed that the physical dimensions of the gap 16 can vary along the length of the triple point region 15. Microscopic analysis can be performed to measure one or more portions of the gap 16 to determine its dimensions.

[0061] This disclosure will now be described with reference to the following examples.

[0062] Example

[0063] Examples 1A, 1B, and 1C of this invention are laminates used as horizontal flow wrapping materials and tested as described below. The test results are shown in Table 1. These samples are similar in form to... Figure 4 The illustrated sealed package.

[0064] Example 1A of the present invention is achieved by using 67g / m 2 It is produced by laminating uncoated bleached kraft paper onto a metallized 8-micron BOPP film. A wet-bonding lamination process is used, with a latex / casein blend adhesive applied at 1.5 g / m³. 2 The weight of the material is applied to the metallized side of the BOPP film for lamination. Natural rubber latex cold-sealing material is then patterned and applied to the non-metallized side of the BOPP film. This cold seal is applied at approximately 5 g / m². 2 pressure and Figure 3 A pattern similar to the one shown is applied. The cold sealant covers approximately 20% of the BOPP film surface. The anti-stick coating is applied at approximately 1.8 g / m². 2 The dry basis is applied to the outer surface of the paper.

[0065] Example 1B of the present invention is produced in a manner similar to that of Example 1A of the present invention. Using 50 g / m³ 2 Paper replaces the 67g / m³ of Example 1A of this invention. 2 Paper.

[0066] Example 1C of the present invention is produced in a manner similar to that of Example 1A of the present invention. An 8-micron OPET film coated with SiOx is used instead of the metallized BOPP film of Example 1A of the present invention. The SiOx coated side of the OPET film is laminated to the paper, and a cold sealing material is patterned and coated onto the OPET side of the laminate.

[0067] Comparative Example 1 is a “common packaging film” produced using a dry-bonding lamination and cold-sealing application technique similar to that of Example 1A of the present invention. As used herein, “common packaging film” is a packaging film that does not include the elements or characteristics of the paper-based packaging film described herein. Since no paper components are used in the common packaging film structure, it is believed that the common packaging film used is not recyclable within the paper recycling stream. The typical packaging film structure has a total thickness of approximately 50 micrometers and is made of BOPP. The cold seal typically uses 3 g / m³. 2 Up to 6g / m 2 The dry weight is applied in a pattern. This type of structure performs well on packaging lines and provides an airtight seal for packaging with triple point regions. Examples of measurements are taken from commercially available and widely used packaging samples.

[0068] Examples 1A, 1B, 1C of the present invention and Comparative Example 1 were configured as flow wrap-type packages, and leaks at the triple point region of the seal were tested according to ASTM D3078. The width of the transverse seal (i.e., the length of the triple point region) was recorded. As can be seen in Table 1, the pressure at the triple point leak detected in the examples of the present invention was significantly higher than that of the tested commercial product. The commercial product (excluding paper components) was verified to have sufficient airtightness. Therefore, it can be concluded that Examples 1A, 1B, and 1C of the present invention provide sufficient airtightness and include improved recyclability (high paper content), ease of packaging conversion, high barrier properties, and airtight sealing characteristics compared to current commercial all-plastic structures.

[0069] Table 1: Overview of airtightness measurements in the triple point region using a modified pressure test (based on ASTM D3078)

[0070]

[0071] Examples 2A and 2B of this invention are laminates used as horizontal flow wrapping materials and tested as described below. The test results are shown in Table 2. These samples are similar in form to... Figure 4 The illustrated sealed package.

[0072] Example 2A of the present invention is to use 50g / m 2 It is produced by laminating uncoated bleached kraft paper onto a SiOx-coated 4.5-micron OPET film. A wet-bonding lamination process is used, with a latex / casein blend adhesive applied at 1.5 g / m³. 2 The weight is applied for lamination. The SiOx coated side of the OPET film is laminated to the paper. A heat-sealable solvent-based polyester material is patterned and coated onto the OPET film side of the laminate. This polyester is approximately 3.5 g / m³. 2 pressure and Figure 3The pattern shown is similar to the one applied. The heat seal covers approximately 20% of the surface of the OPET film.

[0073] Example 2B of the present invention is produced in a manner similar to that of Example 2A of the present invention. In Example 2A of the present invention, the heat-sealable coating is increased to approximately 9 g / m². 2 The weight of the coating.

[0074] Comparative Example 2 is achieved by using 67g / m 2 A packaging film is produced by laminating uncoated bleached kraft paper onto a metallized 8-micron BOPP film. This BOPP film has a heat-sealable surface opposite the metallization. In Comparative Example 2, the heat-sealable surface of this BOPP film is a thin layer of the BOPP film. No other sealing materials are used in the BOPP film. The exact thickness of the sealing layer has not been determined; however, the thickness of the sealing layer is considered to be less than or equal to 2 μm.

[0075] As can be seen from Table 2, the pressure at the triple point leak detected in the example of the present invention was significantly higher than that in Comparative Example 2. The results shown in Table 2 indicate that, for the comparative example, there was insufficient sealing material to fill the gaps formed in areas such as the triple point. To overcome the challenges encountered when performing Comparative Example 2, it is believed that the membrane will need to be combined with additional sealing material. Furthermore, a larger amount of sealing material improves airtightness. When starting from 3.5 g / m³... 2 The sealing material (Example 2A of the present invention) becomes 9 g / m 2 The increased pressure observed when using the sealing material (Example 2B of the present invention) demonstrates the increase in airtightness.

[0076] Table 2: Overview of airtightness measurements in the triple point region using a modified pressure test (based on ASTM D3078)

[0077]

[0078] The embodiments disclosed herein advantageously provide paper-based packaging films with a high paper content. Table 3 shows the different paper contents in various embodiments of the invention. Table 3 shows that, on packaging lines where the packaging form has at least two triple points, the embodiments of the invention have been effectively processed to achieve the predetermined minimum target of 80% paper content by weight.

[0079] Table 3: Overview of paper content and barrier properties in examples of the present invention

[0080]

[0081]

[0082] *Paper content is based on the assumption that the ink content during printing is 1g / m³. 2All sealing coatings have a coverage of 20% and a BOPET density of 1.4 g / m³. 3 Furthermore, the density of BOPP is 0.91 g / m³. 3 It is used for calculation.

Claims

1. A paper-based packaging film, comprising: Paper components, A polymer membrane, comprising a thickness ranging from 2 μm to 10 μm, is coated with a barrier material. Patterned sealable materials, The polymer film is positioned between the paper component and the patterned sealable material. The barrier material is positioned between the polymer film and the paper component, and The overall composition of the paper-based packaging film includes paper components that are greater than or equal to 80% by weight.

2. The paper-based packaging film according to claim 1, wherein, The barrier material is a metal or an inorganic oxide.

3. The paper-based packaging film according to claim 1, wherein, The barrier material is a metal oxide.

4. The paper-based packaging film according to claim 1, wherein, The barrier material is attached to the paper component by an adhesive.

5. The paper-based packaging film according to claim 1, wherein, This sealable material is heat-sealable.

6. The paper-based packaging film according to claim 1, wherein, The sealing material is a pressure-sensitive cold seal.

7. The paper-based packaging film according to claim 1, wherein, The basis weight of this sealable material is 1 g / m³. 2 Up to 10 g / m 2 Within the range.

8. The paper-based packaging film according to claim 1, wherein, The polymer film is one of BOPP film, BOPET film or OPLA film.

9. The paper-based packaging film of claim 1, further comprising an adhesive layer for attaching the paper component to the polymer film.

10. The paper-based packaging film according to claim 9, wherein, The adhesive layer includes a water-sensitive material.

11. The paper-based packaging film according to any one of claims 1-10, wherein, The overall composition of the paper-based packaging film includes paper components that are greater than or equal to 85% by weight.

12. The paper-based packaging film according to any one of claims 1-10, wherein, The overall composition of the paper-based packaging film includes paper components that are greater than or equal to 90% by weight.

13. The paper-based packaging film according to any one of claims 1-10, wherein, The overall composition of the paper-based packaging film includes paper components that are greater than or equal to 95% by weight.

14. A sealed package comprising the paper-based packaging film according to claim 1.

15. The sealed packaging according to claim 14, wherein, The sealed package has a package construction including one or more three-point sealing regions, and each of the three-point sealing regions includes a sealable material.

16. The sealed packaging according to claim 15, wherein, According to ASTM D3078, when a leak test is performed using an internal packaging pressure greater than 20 mbar, no bubbles are emitted from any of the three-point seal areas within the three-point seal region.

17. The sealed packaging according to claim 15, wherein, The packaging is constructed as a free-flowing package or pouch, and the basis weight of the paper-based packaging film is 35 g / m³. 2 Up to 80 g / m 2 Within the range.

18. The sealed packaging according to claim 15, wherein, The packaging structure includes gusseted plates, and the basis weight of the paper-based packaging film is 60 g / m³. 2 Up to 140 g / m 2 Within the range.

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