WO2007137249A2 - Light barrier for package - Google Patents

Abstract

A paperboard structure is described whereby a light barrier is achieved through the use of a coating and without the use of a foil layer.

Description

LIGHT BARRIER FOR PACKAGE

Inventor: Thomas William Kermis

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S. C. § 119(e) of U.S. provisional application serial number 60/747855, filed on May 22, 2006 which is hereby

incorporated by reference in its entirety.

BACKGROUND

[0002] Aseptic packaging is used for foods including many types of drinks. Common styles of aseptic packaging include "pouch" packages and boxes. Popular box-type packages include "juice boxes" and similar containers usually in rectangular shapes and variations thereon, and in sizes typically ranging from a few ounces up to a quart or more.

[0003] FIG. 1 shows a simplified cutaway view of an aseptic box package 10 containing liquid 50. For box type aseptic packages, most of the strength may be provided by a paper or paperboard substrate 110 as shown in detail cross section 100. For liquid packaging, the container must be leakproof, so various materials such as plastic coatings may be used. Many foods and drinks are susceptible to spoilage if exposed to light or oxygen, and therefore additional barrier materials may be used. Barrier materials are typically combined with the substrate paperboard before folding the paperboard into containers.

[0004] A common barrier is aluminum foil, which is especially useful for a light

barrier. For example, as shown by the cross section 100, the layers from the outside to the inside of an aseptic box could be plastic overlay er 118, coating 116 upon which graphics are typically printed, aseptic paperboard 110, first inner plastic layer 122, aluminum foil 124, second inner plastic layer 126, and third inner plastic layer 128. The various layers are provided to achieve desired functionalities. For example plastic overlayer 118 may protect the printed graphics from rubbing off.

[0005] Aluminum foil 124 is somewhat expensive, and incorporating it into the

package adds materials and processing costs. Aluminum foil mixed with the paperboard also may cause difficulties with recycling aseptic paperboard containers.

[0006] FIG. 2 shows a simplified cutaway view of an alternative aseptic box package

20 containing liquid 50. For example, as shown by the cross section 200, the layers from the outside to the inside of this aseptic box could be plastic overlayer 218, coating 216 upon which graphics are typically printed, a paperboard comprising an unbleached ply 210 with an outer bleached ply 212, an inner plastic layer 226, and another inner plastic layer 228. The

various layers are provided to achieve desired functionalities. For example the unbleached ply 210 may provide enough barrier to light so that no aluminum foil layer is required.

However, a two-ply board may be more difficult to produce, and it may be less suitable for recycling since bleached and unbleached paperboard are mixed together.

SUMMARY

[0007] A paperboard structure, and a method of producing the same, is described whereby a light barrier is achieved using a coating rather than a metal foil or additional paperboard plies.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 illustrates a cutaway view of an aseptic box having a foil layer; [0009] FIG. 2 illustrates a cutaway view of an alternative aseptic box having a multiply substrate; and

[0010] FIG. 3 illustrates a cutaway view of an aseptic box in a preferred embodiment of the invention.

DETAILED DESCRIPTION

[0011] FIG. 3 shows a simplified cutaway view of an aseptic box package 30 according to one embodiment of the invention, and containing liquid 50. As shown by cross

section 300, the layers from the outside to the inside of this aseptic box could be plastic overlay er 318, coating 316 upon which graphics are typically printed, a bleached paperboard 310, an inner light barrier coating 321, an inner plastic layer 326, and another inner plastic layer 328. The various layers are provided to achieve desired functionalities. For example the inner light barrier coating 321 may provide enough barrier to light so that no aluminum foil layer and no unbleached ply is required.

[0012] The inner light barrier coating 321 may comprise a light absorbing material, such as carbon black or other dark colored material. It may be applied to the backside of a CIS SBS (coated one side, solid bleached sulfate) aseptic board at a quantity suitable to achieve an acceptable light barrier. Application may be achieved via metered size press, flooded nip size press, water box, coater, or other surface treatment means.

[0001] Developing a light barrier by this method eliminates the use of

aluminum foil as a light barrier in converting, thereby, reducing material costs and

improving converting efficiencies. Aluminum foil also serves as an oxygen barrier. An oxygen barrier can be achieved without aluminum foil by a variety of methods,

including using polyethylene terephthalic silicon oxide (PET SiOx).

[0002] Based on light transmission results, the inventive barrier is comparable to other aseptic substrates being used without foil. These substrates are multiply with significant inclusion of unbleached fiber. The inventive barrier is meant to be used with an entirely bleached fiber substrate, such as a solid bleached sulphate (SBS).

[0003] Methods of making and using the inventive paperboard, or containers or structures made from it, should be readily apparent from the mere description of the laminate structure and its varied appearances as provided herein. No further discussion or illustration of such methods, therefore, is deemed necessary.

[0004] While preferred embodiments of the invention have been described and illustrated, it should be apparent that many modifications to the embodiments and implementations of the invention can be made without departing from the spirit or scope of the invention. Although the preferred embodiments illustrated herein have been described in connection with example structure these embodiments may easily be implemented in accordance with the invention in other structures having different layer configurations, while still utilizing a coating to provide a light barrier. While the description here uses aseptic packages as example embodiments, it is not meant to be limited to aseptic packages. The invention may be applied to packages other than aseptic packages, for example, it may be applied to packages not utilizing a specific layer for an oxygen barrier, or to non-aseptic oxygen-barrier packages. [0005] It is to be understood therefore that the invention is not limited to the particular embodiments disclosed (or apparent from the disclosure) herein, but only limited by the claims appended hereto.

Claims

CLAIMS[0006] What is claimed as new and desired to be protected by Letters Patent of theUnited States is:

1. A sheet material comprising

At least one base layer comprising cellulosic fiber; and

having upon at least one surface of said base layer, a coating that limits or prevents transmission of light through said sheet material.

2. The sheet material of claim 1, wherein said coating comprises carbon.

3. An aseptic package made from the sheet material of claim 1.

4. An aseptic package made from the sheet material of claim 1 , and in the absence of metallic foil.

5. An aseptic package made from the sheet material of claim 1 , said base layer comprising bleached paperboard and in the absence of unbleached paperboard.

6. A package made from the sheet material of claim 1.

7. A package made from the sheet material of claim 1 , and in the absence of metallic foil.

8. A package made from the sheet material of claim 1 , said base layer comprising

bleached paperboard and in the absence of unbleached paperboard.