Patent Application
20070269622
The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein:
While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiments with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein.
Referring now to the figures and in particular to
The carton 10 defines an interior region, indicated generally at 14, in which product is stored, and is illustrated with a closure 16, such as the exemplary spout type closure that will be recognized by those skilled in the art. The spout closure 16 provides excellent resealability, while maintaining the carton 10 closed to prevent the ingress of oxygen into the carton 10 from the dispensing opening 16.
The carton 10 is formed from a laminated material 12, such as that shown in
From the core layer 18 to the outside of the carton indicated generally at 20, the material 12 includes a layer of a moisture-resistant polymeric material 22 disposed on an outer surface 24 of the core layer 18. The material 22 is typically a non-polar polymeric material. Presently, one material that is used is LDPE. LDPE is used because of its high-moisture barrier characteristics, relatively low cost and ease of use. LDPE is also approved for use in both food contacting and non-food contacting surfaces for food packaging materials. Also acceptable are linear low density polyethylene (LLDPE) and metallocene-based linear low density polyethylene (m-LLDPE), and blends of these materials.
In the embodiment 12 illustrated in
In a present composite 26, the LDPE layers 30, 38 are a grade 4001i resin, commercially available from Dow Chemical Co., of Midland, Mich. The tie layers 32, 36 are an anhydride modified LDPE, such as BYNEL, Series 4288, commercially available from DuPont, of Wilmington, Del. The tie layers 32, 36 serve as an adhesive between the LDPE layers 30, 38 and the nylon 34. It will be understood that the LDPE layers 30, 38 function as a moisture barrier and as a seal layer.
Due to the method of dividing and stacking the initial LDPE/tie/nylon/tie/LDPE structure, as it comes out of the extruder, a generic barrier structure now becomes a low scalping barrier structure since the nylon is deposited in close proximity to the product. In the present composite 26, the nylon layer 34 serves as a low scalping member, thus preventing the loss of flavor and nutrients (e.g., as in the loss of d-limonene). The nylon layer 34 material (which is an polyamide resin) is commercially available as MXD6 6011 from Mitsubishi Chemical Corporation of Chesapeake, Va. Other nylon materials (such as PA6 and PA6,6, and blends thereof) and tie layer materials will be recognized by those skilled in the art.
The combination of the LDPE 30, tie 32, nylon 34, tie 36, LDPE 38 is applied in a repeating pattern or structure 28, rather than as a single set of layers to form the composite 26. Accordingly, the inside of the packaging material 12 is, when viewed in cross-section, paperboard 18, LDPE 30′, tie 32′, nylon 34′, tie 36′, LDPE 38′, LDPE 30″, tie 32″, nylon 34″, tie 36″, LDPE 38″, . . . , LDPE 30″″, tie 32″″, nylon 34″″, tie 36″″, LDPE 38″″, in a predetermined number n of repeating series 28. This can also be viewed as paperboard 18, (LDPE 30, tie 32, nylon 34, tie 36, LDPE 38)n, wherein n is a whole number multiple. In a present material, the number of series n is a geometric progression of 4 (e.g., n=4, 8, 16, 32, . . . ).
It has been found that this arrangement functions quite well in that the LDPE layers 30, 38 that lie adjacent one another bind or adhere well and that the LDPE layers 30, 38 bind or adhere well to the paperboard 18. In has been observed that the tie layers 32, 36 are needed adjacent the nylon layer 34, in that the nylon 34 and LDPE layers 30, 38 do not adhere well to one another.
The series 28 are applied at a weight that, in the aggregate, is no more than the weight that a single series would be applied. In a present material 12, the aggregate weights of the LDPE-tie-nylon-tie-LDPE are 15-5-6-5-15 grams per square meter of material. In that these are aggregate amounts, if the number of series n is 4, then there are four series 28′-28″″, and each series has layers, 30′-30″″, 32′-32″″, 34′-34″″, 36′-36″″ and 38′-38″″ having a weight of material of 15/4-5/4-6/4-5/4-15/4. Accordingly, each of the layers is also thinner.
It has also been observed that this arrangement functions well to reduce the scalping effect of the LDPE layer 30′ in that the nylon layer 34′ (which is a barrier to scalping) is closer to the product than if a single series (structure) arrangement was used. Thus, because the first nylon layer 34′ is closer to the product, which corresponds to a thinner LDPE layer 30′ or less LDPE in the initial layer contacting the product, the overall scalping effect of the LDPE is greatly reduced. This is because the volume (or mass) of LDPE in the initial layer 30′ that contacts the product is reduced, thus reducing the amount of d-limonene that can be absorbed in that LDPE layer 30′.
In a typical material 12 manufacturing process, the various layers 30, 32, 34, 36, 38 are extruded or coextruded onto the paperboard 18. In order to achieve the serial application or multiple series of LDPE 30—tie 32—nylon 34—tie 36—LDPE 38, a flow multiplier or micro-layer insert (in the die neck) is used, such that the flow stream of each of the layers is divided into the desired number or series. In this manner, if the number of series is 4, then the nylon is divided into four streams of 6/4 or 1.5 gsm (equivalent). A schematic illustration of a multiplier or microlayer feedblock 202 is illustrated in
It has been found that by minimizing the polyolefin (LDPE) seal layer 30′ and by placing a barrier layer (nylon) 34′ in close proximity to the inner surface 40 of the seal layer 30′, scalping of the flavor oils (e.g., d-limonene) can be reduced. With the use of a micro-layer structure 28′, 28″, 28′″, 28″″, . . . , 28n, a barrier 12 formed from standard and known materials can be provided that is applied in multiple thin layers distributed throughout the entirety of the layered structure (the material laminate 12) to achieve lower scalping characteristics. The overall result of the micro-layered structure 28′, 28″, 28′″, 28″″, . . . , 28n can be a lower cost package material (due to a possible reduction in nylon application from 9-11 gsm to 5-7 gsm), the creation of a tortuous path (by multiple layers) for the ingress or penetration of oxygen, enhanced strength with layering reduces the possibility of pinholes, the extrusion of more (a larger number of) thinner layers of material, and an improved stacked alignment of fillers (such as talc, calcium carbonate, nanoclays and the like) that may be added to one or more of the layers. The thinner layers provide better dispersion of the filler material and reduce the opportunity for the filler materials to clump (uneven distribution) or to improperly orient within the material layer.
Also advantageously, it has been found that extruding thinner LDPE layers 30, 38 improves the overall strength of the material. In addition, it has been found that MXD6 (as the nylon layer 34), which is brittle in extrusion coating and is otherwise challenging to extrude alone, when extruded in thinner layers between the also thinner olefin layers 30, 38, tends to be more workable and shows improved converting performance.
It will be appreciated that although specific materials are disclosed for the LDPE 30, 38, tie 32, 36 and nylon 34 layers, other suitable materials can be used in the present microlayer low scalping barrier packaging material 12. For example, suitable materials for the barrier, nylon layer 34, can include ethylene vinyl alcohol (EVOH) or other like oxygen barriers. Olefins other than LDPE can be used for the olefin layer 32, 38, for example, olefins having a density of about 0.0922-0.0924 will also likely be suitable.
An alternate embodiment of the laminated material 112 is illustrated in
In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular.
From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.
