Patent Application
20170021595
Disclosed herein is an improved lamination structure for use as a packaging material, particularly a material suitable for use in the packaging of cream cheese and similar brick- or loaf-type product packages.
Historically cream cheese brick- or loaf-type packaging (see e.g. for 8 oz.,
One particular example of a structure for eight-ounce cream cheese packages has the following characteristics: (i) Over-lacquer/(ii) Ink-Flexo or Roto Printed/(iii) Foil-(0.00033 to 0.00035″)/(iv) Poly Urethane Type Lamination Adhesive (applied in range of 1-3 #/ream (rm))/(v) 48ga PET/(vi) Wax Compounds (applied in range of 20-30#/rm). As used herein, the abbreviation “rm” is intended to refer to a “ream” and unless otherwise indicated a 3000 sq. ft. ream. The known structure and its reasonable cost has been effective in providing a low initial heat sealing temperature (HSIT) in the range of 150° F. to 165° F. as well as adequate hot tack such that it seals and holds that seal during filling, which can be at temperatures approaching 170° F. One feature of the wax layer is that the wax has the ability to flow into the seal areas to properly caulk the gusset area as well as side seals. The seal strength of the wax is low enough to allow the consumer to peel open the package without tearing the packaging material. Because the wax used as a sealant has a softening temperature below the package fill temperature (170° F.) it does not always insure a hermetic seal. The low HSIT and caulking characteristics reduce leakage rates and generally avoid open bottom seals. However, using wax as a sealant does not insure a hermetic seal, which is a desirable characteristic, particularly for a product susceptible to mold. Another advantage of the package structure is that there is very good deadfold for the pouch fabrication and filling process.
The embodiments disclosed herein seek to replicate or improve upon the performance of the known package materials. As part of the converting process for the known structure an embossed pattern may be placed into foil by a deep anilox roll that is employed in the application of the wax. The embossed pattern is shown in the pictures of
The general sealant structure summarized is also used for 1, 2, 3, and 5 pound loaves of cream cheese. For purposes of this document and to provide examples of materials and processes to replace wax as the sealant layer, the 8 oz. cream cheese structure will be used to further describe the structures and methods.
While the structure of
From a food safety perspective, dairy processors recognize the risks and shortened shelf life caused by the non-hermetic 100% wax seal. As a preferred manufacturing practice diary producers want to limit the amount of inorganic compounds admitted to their processing environments.
There have been attempts at using sealant films in the range of 1-2 mil thick low-density polyethylene (LDPE) in the packaging material structure to replace the wax sealant. In general, however, nearly 100% polyolefin type materials do not exhibit adequate HSIT and hot tack characteristics, and do not provide the flow and caulking needed for proper sealing when used on current filling equipment. Films also resist folding and will unfold when relaxed due to the elastic nature of polyethylene.
In accordance with the embodiments disclosed herein examples of the general structure contemplated are as follows: Over-lacquer/Ink/Foil/Adhesive/PET/Extrusion Coated Polymer(s). Applications for the improved packaging material structure Include cream cheese packaging, as illustrated in 8 oz. packages.
Disclosed in embodiments herein is a packaging material structure for use in a package, such as a three-side seal style pouch or a flow wrap with end seals and either a fin or lap seal in the machine direction of the package, comprising: a foil, and on one surface of said foil an ink layer along with an optional over-lacquer layer; an adhesive layer on the opposite side of the foil layer and a PET layer having an extrusion coated polymer(s) thereon.
Further disclosed in embodiments herein is a packaging material structure wherein the thickness of said foil is in the range of about 0.000285″ to about 0.00033″, where said adhesive layer includes a poly-urethane adhesive applied in range of about 1-3 lbs./ream (#/rm), where said PET layer has a thickness of about 48 gauge, and where the extrusion coated polymer is applied within a range of about 10-15#/rm.
Also disclosed herein is a packaging material structure wherein the thickness of said foil is in the range of about 0.000285″ to about 0.00033″, where said adhesive layer includes a poly-urethane adhesive applied in range of about 1-3 lbs./ream (#/rm), where said PET layer has a thickness of about 48 gauge, and where the extrusion coated polymer is a co-extrusion of a first and a second polymer applied within range of 10-15#/rm.
Further disclosed is a packaging material structure wherein the thickness of said foil is in the range of about 0.000285″ to about 0.00033″, where said adhesive layer includes a poly-urethane adhesive applied in range of about 1-3 lbs./ream (#/rm), where said PET layer has a thickness of about 48 gauge, and where the extrusion coated polymer is an extrusion coated hot melt applied within range of about 10-15#/rm.
Also disclosed in embodiments herein is a packaging material structure, further including a polyethylene (PE) extrusion lamination layer between the foil and the PET layer, where said polyethylene (PE) extrusion lamination layer is applied within range of about 4-7#/rm.
The various embodiments described herein are not intended to limit the disclosure to those embodiments described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the various embodiments and equivalents set forth. For a general understanding, reference is made to the drawings. In the drawings, like references have been used throughout to designate identical or similar elements. It is also noted that the drawings may not have been drawn to scale and that certain regions may have been purposely drawn disproportionately so that the features and aspects could be properly depicted.
As noted above, there is a need within the packaging industry to address sealant and structure options in order to provide alternatives to a full wax package sealant, particularly in three-side seal pouch style packages and fin seal flow wrap style packages, both of which may be employed to produce brick- or loaf-type package shapes. For example, the sealed seal horizontal flow wrap or three-side seal formed pouch may be used to encapsulate a brick of cream cheese or similar foodstuff where hermetic sealing may be desirable. The following discussion, while described relative a three-side seal style, is applicable to any package style or configuration, and particularly including a fin seal flow wrap style package. The embodiments disclosed herein present materials, material placement within a flexible packaging structure, and processing methodologies to resolves those challenges. The disclosed embodiments also result in potential ways to down gauge the structure, which in turn provides a more sustainable package by using less material especially less fossil fuel materials.
A three-side seal style package is illustrated, for example, in
The use of low initial heat sealing temperature (HSIT) polymers such as High VA containing EVA Resins or customized polymeric compounds made with high VA containing EVA resins were addressed. These may include resins or compounds from companies such as Arkema, AT Plastics, Bostik, Celanese Dupont, and Henkel. The use of multi-layer co-extrusion technology allows the use of polymer layers that optimize adhesion to the adjacent film within the structure (PET in this case) and optimize low HS IT for package sealing.
The co-extrusion resins could be of the type within the Bynel and/or Appeel family of Dupont resins. The disclosed alternatives provide structures that are adequate and provide sealing temperatures within a desirable range for this application (e.g., packaging of cream cheese).
While known that a wax layer has the ability to flow into the seal areas to “caulk” the gusset area as well as side seals, to provide a “peel-open” package, the wax does not always insure a hermetic seal. Hence, using wax as a sealant does not insure a hermetic seal. Several of the embodiments disclosed herein seek to replicate or improve upon the performance of the known package materials, including an embossed pattern may be placed into the foil and associated layers—for example, using a deep anilox roll that is employed to produce the pattern as shown in
As noted above, and referring to
As will be appreciated and should be stressed, all of above options may also take the format of: Over-lacquer/Ink/Foil/PE Extrusion Lamination in range of 4-7#/rm/PET/Extrusion Coated Polymer(s).
The types of polymers and extrudable EVA based compounds that provide properties believed desirable for a packaging structure to replace a purely wax based heat-seal layer in the structure include the following, some of which may be more ideal or optimum for the use requirements. Compounds of high VA containing ethylene vinyl acetate (EVA) and polyethylene (PE) polymer, and possibly low percentages of wax, that may be added to latter polymers to enhance or alter the seal initiation temperature. The latter is shown in the graphs below, where some are more optimum or ideal, and the reason for presenting the differences is to illustrate that modifications are needed within commercially available compounds and that off-the-shelf solutions may be not be an ideal solution. The B-R is an example of how modifications facilitate a more ideal situation for HSIT. It should be appreciated that by merely taking off-the-shelf compounds the resulting structure may not provide ideal sealing or filling conditions. The other resins fall within a range that gives much higher HSIT's.
When such polymers and hot melts were extrusion coated onto structures having layers and characteristics noted above, these resins provided sealing results and seal curves (seal strength) as illustrated, for example in
For example, referring to
Referring to
As will also be appreciated, as part of using these polymer materials, a special coated PET, as supplied to a converter, could be employed so one would not have to use special primers on that PET during the in-line lamination process—thereby saving both the cost of the primers as well as the need to include that operation in the manufacturing process.
Turning next to
Additional physical testing was conducted on the samples of
For certain sealant options extrusion processing conditions had to be adjusted to accommodate the polymers. These include adjustments in air gap (increasing air gap from 5″ to 7″) chill roll temperature (decreasing temperature by 10 to 15 ° F.), and insuring the chill roll matte surface has a surface roughness. The Ra value (Average Roughness) may be in the range of about 70 to 90 Ra for the Matte Chill Roll used for processing the wax replacement structures. While this Ra value may not be unique by itself, it provided the proper release from the chill roll for the polymers selected, i.e.: B-R and B-W, along with the proper air gap, chill roll temperature. The chill roll temperature was about 50-55 F for processing on the lines and is anticipated for production.
In one method of production, the general flow or processing for a structure such as disclosed above would be to combine the foil layer 314 with the PET layer 318 (and adhesive 316) as part of either an adhesive or extrusion lamination process and then apply the sealant polymer (layer 320) in-line to the exposed PET surface.
It should be understood that various changes and modifications to the embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present disclosure and without diminishing its intended advantages. It is therefore anticipated that all such changes and modifications be covered by the instant application.
This application claims priority under 35 USC §119(e) from U.S. Provisional Patent Application No. 62/194,547 for EXTRUSION AND ADHESIVE LAMINATIONS USING UNIQUE EXTRUSION COATED SEALANTS TO REPLACE WAX, filed Jul. 20, 2015 by B. Muehl et al., which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62194547 | Jul 2015 | US |
