RECYCLABLE PAPER AND METHOD AND RECYCLING THE SAME

Description

FIELD OF THE INVENTION

Embodiments of the present invention relate generally to paper packaging, and more particularly, to recyclable paper packaging.

BACKGROUND

Flexible packaging structures are generally made from multiple polymeric components, often comprising layers of different polymeric films laminated together to achieve desired properties. The layered, laminated films provide desired barrier properties, however, are generally not recyclable in a standard recycling stream due to the multiple different polymers contained therein.

Similarly, existing paper packaging products may include some polymeric components or coatings to supply barrier properties similar to those of plastic film packages (i.e., moisture and oxygen barriers). Further paper packaging products may include dyes or ink layers to provide an indication of the goods within the paper packaging products. In order for a paper product to be recyclable, the recycling process must return a minimum percentage of the fibers from the initial product, generally at least 80% total weight, or at least 85% total weight, based on bone dry fiber charge to the pulper. However, coatings, inks, adhesives and additives applied to paper generally encapsulate the fibers of the paper during the manufacturing process. During repulping/recycling, the encapsulated fibers may agglomerate. These coatings do not easily separate or remove themselves from the fibers during the recycling process and, therefore, coated paper packaging is often unable to be recycled.

Through ingenuity and hard work, the inventor has developed a recyclable paper for use in packaging, which utilizes a water soluble coating layer, to provide separation between the paper layer and other layers to aid in the recyclability thereof, and a method for making the same, such that when the recyclable paper is subject to a repulping process the paper fibers recovered are able to be recycled without further processing. Further, the recyclable paper may be manufactured and recycled with existing machinery.

BRIEF SUMMARY

In an embodiment, the invention comprises a recyclable paper packaging structure having a water soluble coating adjacent the paper layer. The coating layer is configured to dissolve, such that when the paper packaging structure is subject to the repulping process the coating layer dissolves, causing the paper layer to separate from adjacent layer(s).

The present invention comprises a coating layer which prevents encapsulation of the paper fibers, thereby providing a higher more quality yield of paper fibers during the recycling and recovery process. Further, the coating layer prevents dyes or inks from penetrating the paper fibers, therefore the paper fibers recovered after the repulping process are a desired color.

In an example embodiment a recyclable structure is provided. The recyclable structure comprises a paper layer defining an inner surface and an outer surface opposite the inner surface. The recyclable structure further comprises a coating layer disposed adjacent at least one of the inner surface or the outer surface of the paper layer. The coating layer is water soluble. The recyclable structure further comprises at least one second layer adjacent the coating layer.

In some embodiments, the coating layer may be a modified starch. In some embodiments, the coating layer may be a food grade starch. In some embodiments, the coating layer may define a low molecular weight. In some embodiments, the coating layer may be printable onto the paper layer.

In some embodiments, the coating layer may be a first coating layer, and the at least one second layer may be an outer second layer and an inner second layer. The recyclable structure may further comprise a second coating layer. The first coating layer may be disposed on the inner surface of the paper layer, and the inner second layer may be disposed on the first coating layer. The second coating layer may be disposed on the outer surface of the paper layer, and the outer second layer may be disposed on the second coating layer.

In some embodiments, when the coating layer is exposed to water, the coating layer may be configured to dissolve so as to separate the paper layer and the at least one second layer. In some embodiments, the at least one second layer may be an ink layer. In some embodiments, the at least one second layer may be a polymeric layer. In some embodiments, the at least one second layer may be an electron-beam coating. In some embodiments, the recyclable structure may further comprise a layer of aluminum oxide on the electron-beam coating. In some embodiments, the recyclable structure may further comprise a heat seal layer adjacent the at least one second layer opposite the coating layer. In some embodiments, the coating layer may have a degree of hydrolysis between 70%-100%.

In another example embodiment a recyclable structure is provide. The recyclable structure comprises a paper layer defining an outer surface and an inner surface opposite the outer surface. The recyclable structure further comprises a first coating layer disposed adjacent the inner surface of the paper layer, and the coating layer is water soluble. The recyclable structure further comprises a primer positioned adjacent the first coating layer, and a barrier layer adjacent the primer layer.

In some embodiments, the recyclable structure may further comprise a second coating layer disposed adjacent the outer surface of the paper layer, and an ink layer disposed on the second coating layer. In some embodiments, the primer may be an adhesive and the barrier layer may be a polymeric barrier. In some embodiments, the barrier layer may comprise an electron-beam coating. In some embodiments, the coating layer may have a degree of hydrolysis between 70%-100%.

In yet another example embodiment a method of forming a recyclable structure is provided. The method comprises printing a water soluble coating layer onto an inner surface or an outer surface of a paper layer, the inner surface being opposite the outer surface. The method further comprises applying at least one second layer adjacent the coating layer.

In some embodiments, the at least one second layer may be one of a barrier layer or an ink layer.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1A illustrates a cross-sectional view of an example paper packaging structure, in accordance with some embodiments discussed herein;

FIG. 1B illustrates a cross-sectional view of the paper packaging structure of FIG. 1A when exposed to the recycling process, in accordance with some embodiments discussed herein;

FIG. 2A illustrates a cross-sectional view of an example paper packaging structure, in accordance with some embodiments discussed herein;

FIG. 2B illustrates a cross-sectional view of an example paper packaging structure, in accordance with some embodiments discussed herein

FIG. 3 illustrates a cross-sectional view of an example paper packaging structure, in accordance with some embodiments discussed herein;

FIG. 4 illustrates a cross-sectional view of an example paper packaging structure, in accordance with some embodiments discussed herein; and

FIG. 5 illustrates a process diagram for forming an example paper packaging structure, in accordance with some embodiments discussed herein.

DETAILED DESCRIPTION

Example embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout.

Paper packaging products may require direct printing onto the paper layer for indications of the goods contained therein, and other source identifiers. Similarly, paper packaging products may require barrier properties to preserve the condition of the contents of the packaging. Each of printing and barrier layers may cause contamination to the paper fibers of the paper layer, which may prevent recycling in the normal stream.

A recyclable paper packaging structure is provided herein, which minimizes and/or prevents contamination of the paper fibers within the paper layer, while providing similar barrier properties as polymeric packaging structure. In an embodiment, a paper packaging structure is provided wherein a coating layer is positioned between the paper layer and at least one second layer, thereby separating the paper fibers from the at least one second layer. Upon repulping, the coating layer dissolves, allowing separation of the paper layer from any additional layers, thereby maintaining the recyclability of the paper layer.

FIG. 1A illustrates an example paper packaging structure 100. The packaging structure 100 may define a first surface 100a and a second surface 100b opposite the first surface 100a. In some embodiments, the first surface 100a may be an outer surface of the packaging structure 100 and the second surface 100b may be an inner surface of the packaging structure 100.

In an embodiment a paper layer 110 may comprise the majority of the packaging structure 100, by weight (not illustrated to scale). In some embodiments, the paper layer 110 may account for up to 70% total weight of the packaging structure 100, or in another embodiment up to 80% total weight of the packaging structure 100, or in still another embodiment more than 90% of the total weight of the packaging structure 100. In some embodiments, the paper layer 110 may account for between 85-95% of the total weight of the packaging structure 100.

In some embodiments, the paper layer 110 may comprise only virgin paper, while in other embodiments, the paper layer 110 may comprise only recycled paper (post-consumer or post-industrial). In some embodiments, the paper layer 110 may comprise a mix of recycled paper and virgin paper.

The paper layer 110 may define an outer surface 110a and an inner surface 110b. The outer surface 110a may form the outer first surface 100a of the structure 100, and the inner surface 110b of the paper layer 110 may bond with other structures.

In some embodiments, a coating layer 120 may be positioned on the inner surface 110b of the structure, and at least one second layer 115 may be positioned on the coating layer 120. The coating layer 120 may be configured to coat the paper fibers of the paper layer 110 and prevent the at least one second layer 115 from engaging with (e.g., penetrating, encapsulating, coating, etc.) the paper fibers of the paper layer 110. In some embodiments, the coating layer 120 may provide barrier properties to the packaging structure 100, for example, a gas barrier and/or moisture barrier. Optionally, in some embodiments, a primer 117 may be positioned between the coating layer 120 and the at least one second layer 115. The primer 117 may promote adhesion, between the layers, or otherwise prime the coating layer 120 for application of the at least one second layer 115.

In some embodiments, the coating layer 120 may be a modified starch. The modified starch may have a low molecular weight. In some embodiments, a food grade starch may be used in the coating layer 120. Since the coating layer 120 may be used in food packaging, and in some embodiments, may at least partially abut a food product, the coating layer may comprise food grade starch to meet regulations.

In some embodiments, the coating layer 120 may be printed onto the paper layer 110. In this regard, the viscosity of the coating layer 120 must be compatible with the printing device. In some embodiments, the coating layer 120 may be applied with a gravure press. In other embodiments the coating layer 120 may be applied through spraying, vapor deposition, roll coating, or any other method of application known in the art.

The viscosity of the coating layer 120 may correspond to the solids content within the layer. In some embodiments, the coating layer 120 may have a viscosity between 30 cps-700 cps, preferably between 40 cps-600, and more preferably between 50 cps-500 cps. In some embodiments, the viscosity of the coating layer 120 may correspond to the solids within the coating layer 120.

	TABLE 1
	Viscosity (cps)	Solids %

	479	19.2
	154	14.52
	50	10.0

For example, as illustrated in Table 1 a higher viscosity contains a higher solids content while a lower viscosity contains a lower solids content. In some embodiments, coating layer 120 may comprise between 5%-25% solids, between 7%-23% solids, or more preferably between 10%-20% solids.

As illustrated in Table 1 the solids content of the starch may impact the viscosity of the coating layer 120. Although, the coating layer 120 may be diluted to attain the desired viscosity, the composition of the coating layer 120 must comprise a sufficient amount of the modified starch, such that any additional layers (e.g., the at least one second layer 115, the adhesive layer 117) do not penetrate through the coating layer 120 into the paper layer 110.

In some embodiments, the coating layer 120 may be a low hydrolysis polyvinyl alcohol (PVOH). The low hydrolysis PVOH may exhibit above 50% hydrolysis, above 60% hydrolysis, or above 70% hydrolysis. In some embodiments, the low hydrolysis PVOH may have a hydrolysis between 50%-100% between 60%-100% or even between 70%-100%. In an example embodiment the low hydrolysis PVOH may have about 74% hydrolysis.

In some embodiments, an additive may be positioned between the coating layer 120 and the paper layer 110. The additive may be a talc or a clay. The additive may increase the quality of the surface of the paper layer 110. For example, the additive may smooth out any bumps or ridges in the surface of the paper layer 110.

In some embodiments, the structure 100 may further include a heat seal layer 150. The heat seal layer 150 may be applied to the at least one second layer 115. Further, in some embodiments the heat seal layer 150 may form a portion of the second surface 100b of the packaging structure 100. In this regard, in some embodiments, the heat seal layer 150 may be an interior surface and may be configured for sealing around an object to form a recyclable package, such as a pouch, as will be discussed further herein.

In some embodiments, the coating layer 120 may be water soluble. In this regard, as illustrated in FIG. 1B, when the structure 100 is introduced into a recycling process after use, the coating layer 120 may dissolve thereby separating the paper layer 110 from the at least one second layer 115.

The paper packaging structure may be easily recycled in the normal stream according to the recycling standards set forth in “Voluntary standard for Repulping and Recycling Corrugated Fiberboard Treated to Improve its Performance in the Presence of Water and Water Vapor,” which is incorporated herein in its entirety. After use, a user may place the paper packaging structure 100 in the normal recycling stream (i.e., curbside). The paper packaging structure is then subjected to a standard recycling process, wherein the paper packaging structure is shredded. The shredded paper is exposed to water and other chemicals and repulped. The shredded paper may be homogenized to separate out polymeric flakes. The repulping slurry is filtered through a screen where the unrecyclable components (e.g., the at least one second layer, and heat seal layer) are removed either in a solution with the coating layer 120 and water or are filtered out. The remaining recyclable products (e.g., the paper fibers) are recovered, exhibit the proper color, and other desirable qualities for fiber recovery. In some embodiments, the paper packaging structure is able to recover at least 85% of the original paper fibers from the paper layer.

In an example embodiment, the at least one second layer may be configured to provide additional barrier properties to the packaging structure, for example a moisture barrier or a gas barrier, to keep the contents of the packaging fresh prior to use. In some embodiments, the barrier layer may provide a barrier for migratory components between the product and the paper layer. In some embodiments, the barrier layer may prevent any grease, mineral oil or similar from transferring from the product to the paper layer, thereby preventing grease stains or creases within the paper layer.

An example paper packaging structure 200 may comprise a paper layer 210 defining an outer surface 210a and an inner surface 210b. A coating layer 220 may be applied to the inner surface 210b of the paper layer 210. In the illustrated embodiment, the at least one second layer may be an electron beam coating 230 and optionally a metalized layer 235. In some embodiments, the metalized layer 235 may comprise AlOx or SiOx. In such an embodiment the coating layer 210 may prevent the electron beam coating from encapsulating the paper fibers of the paper layer 210, as the coated paper fibers may not yield a sufficient recovery of paper fibers during the recycling process. Rather, electron beam coating 230 may engage with the coating layer 220 which dissolves during the repulping process, thereby allowing the electron beam coating 230 and the metalized layer 235 to release from the paper layer 210. Optionally, in some embodiments a primer (e.g., 117 FIG. 1A) may be positioned on the coating layer 120 to prime the surface for the electron beam coating 230. Although the second layer is discussed as being an electron beam coating, it should be understood that other barrier layers may be used, for example, a polymeric barrier.

With reference to FIG. 2B, in another example embodiment a paper packaging structure 200′ may utilize a polymeric layer 255 for at least one second layer. In such embodiments an adhesive 217 may be positioned adjacent the coating layer 220 to promote adhesion between the coating layer 220 and the polymeric layer 255. In some embodiments, the polymeric layer 255 may comprise polyethylene, polypropylene, polyethylene terephthalate, or similar, to provide desired gas and moisture barrier properties. In some embodiments, the polymeric layer 255 may be an oriented polymer, for example, oriented polypropylene or oriented polyethylene. In some embodiments, the polymeric layer 255 may define a thickness between 5-7 microns.

In another example embodiment, the coating layer may be used to prevent an second layer from dying, or otherwise contaminating the paper fibers. To explain, ink, when applied to paper may penetrate into the paper fibers, and effectively dye the paper fibers. After the repulping process the recovered fibers may be dull and, in some instances, may be rejected due to the discoloration of the fibers.

As illustrated in FIG. 3, to prevent an ink layer 340 from dying, or otherwise contaminating the paper fibers a coating layer 320 may be applied to a first surface 310a of a paper layer 310, such that the ink layer 340 defines a first surface 300a of the structure 300 and a second surface 310b of the paper layer 310 defines a second surface 300b of the structure 300. In such embodiments the coating layer 320 minimizes and/or prevents the ink from penetrating into the paper layer 310, such that the paper fibers have a desirable color after the repulping process.

Still further, it may be desirable to have a paper packaging structure with layers on either surface of the paper layer, for example, to provide barrier properties, and indicate the source of the goods contained within. Thus, as illustrated in FIG. 4, a paper packaging structure 400 may comprise a paper layer 410 defining a first surface 410a and a second surface 410b, each having a coating layer applied thereto.

In some embodiments, a first coating layer 420a may be applied to the first surface 410a of the paper layer 410, and a second coating layer 420b may be applied to the second surface 410b of the paper layer 410. An ink layer 440 may be applied to the first coating layer 420a, such that the ink layer 440 may define an outer surface 400a of the paper packaging structure 400. In some embodiments, a barrier layer comprising an electron beam coating 430 and, optionally a metallization layer 435 may be applied onto the second coating layer 420b. the barrier layer, may define an inner surface 400b of the paper packaging structure 400.

In some embodiments, the inner surface 400b of the paper packaging structure may be a product facing surface, and thus, each of the barrier layer components, the electron beam coating 430 and the optional metallization layer 435 may be food safe.

Thus, when the paper packaging structure 400 is introduced into the recycling stream for repulping the first coating layer 420a and the second coting layer 420b will dissolve thereby releasing the ink layer 4340 and the electron beam coating 430 and the metallization layer 435 from the paper layer 410.

Method of Manufacture

In the method of manufacture, referring to FIG. 5, a paper layer 510 may be advanced from a first structure supply roll 514. The paper layer 510 may be advanced to a coating application station 525 wherein a coating layer is applied to one or both surfaces of the paper layer 510. The coated paper layer is the advanced to a second layer application 517, wherein the at least one second layer (e.g., ink layer or barrier coating layer) is applied to the coated surface of the paper layer. The paper structure 100 may then be optionally advanced to a processing station 260 to be cut, rolled, stacked, or otherwise prepared for transportation or application for subsequent processing in a second, offline phase of the manufacturing process.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the embodiments of the invention are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the invention. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the invention. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated within the scope of the invention. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.