Patent Application
20240308740
N/A
The disclosure relates in general to packaging, and more particularly, to a recyclable film for a pouch and a pouch assembly formed from a recyclable film.
The use of flexible packaging is well known in the art. Among other types of packaging, one common type of packaging is a pouch filled with a flowable material. Such pouches typically have a spout that is sealed between two layers which form the body of the pouch. Such pouches may further be gusseted or may include a lower gusset opposite the spout or space away from the spout.
Such pouches are typically made from polyethylene based films. Such films, based solely on polyethylene generally do not exhibit adequate oxygen barrier properties. Thus, additional barrier layers are added, often formed from an Ethylene vinyl alcohol (EVOH) material. Problematically, the inclusion of barrier layers can limit the recyclability of the overall pouch or the films associated with the pouch. On the other hand, if the amount of EVOH is minimized to a level at which recyclability is possible, it is often the case that the resulting film exhibits poor oxygen permeation.
The disclosure is directed to a film for a pouch comprising a central layer, a first LLDPE tie layer, a second LLDPE tie layer, at least one outside HDPE layer, at least one inside HDPE layer and an inner LLDPE layer. The central layer comprises an EVOH, having an inside and an outside opposite the inside and a thickness. The first LLDPE tie layer is on the inside of the EVOH. The second LLDPE tie layer on the outside of the EVOH. The at least one outside HDPE layer is on an outside of the second LLDPE tie layer opposite the EVOH layer. The at least one inside HDPE layer is on an inside of the first LLDPE tie layer opposite the EVOH layer. The inner LLDPE layer is on an innermost one of the at least one inside HDPE layer. The inner LLDPE layer, first LLDPE tie layer and the at least one inside HDPE layer define an inside PE thickness. The second LLDPE tie layer and the at least one outside HDPE layer define an outside PE thickness. The inside PE thickness is at least twice the thickness of the outside PE thickness.
In some configurations, the central layer has a thickness of between Sum and 10 um, and wherein the film defines an overall thickness that is between 110 um and 115 um.
In some configurations, the outside and the inside HDPE layers have a density that is greater than 0.94 g/cc.
In some configurations, the first and second LLDPE layers have a density that is less than 0.93 g/cc.
In some configurations, the inner LLDPE layer comprises the innermost layer of the film.
In some configurations, the inner LLDPE layer includes mPE.
In some configurations, the inner LLDPE layer comprises 53% LLDPE and 41% mPE.
In some configurations, the inner LLDPE layer further includes anti-block master-batch and polymer processing aid (PPA) master batch.
In some configurations, the thickness of the HDPE layers on the inside of the EVOH layer is greater than a thickness of the HDPE layers on the outside of EVOH layer.
In some configurations, the EVOH layer comprises a 29 mol % ethylene EVOH layer.
In some configurations, the film comprises a co-extrusion.
In another aspect of the disclosure, the disclosure is directed to a pouch assembly comprising a pouch and a spout. The pouch has at least two opposing walls that are sealed together to form a cavity. The spout is sealed to at least one of the opposing walls. The spout provides ingress into the cavity. The opposing walls are formed from the film set forth above and hereinbelow, with the inner LLDPE layer of a first one of the opposing walls sealed to the inner LLDPE layer of the second one of the opposing walls.
In some configurations, the spout is sealed to each of the opposing walls.
In some configurations, the pouch assembly further includes a gusset sealed to each of the opposing walls. The gusset is formed from the film set forth above and hereinbelow, with the inner LLDPE layer of the gusset sealed to each of the inner LLDPE layer of the first one of the opposing walls and the inner LLDPE layer of the second one of the opposing walls.
In some configurations, each of the at least two opposing walls defines a thickness. The thickness is between 110 um and 115 um, and more preferably, between 113 um and 114 um.
In some configurations, the EVOH layer comprises a 29 mol % ethylene EVOH having a thickness of between 5 um and 10 um.
The disclosure will now be described with reference to the drawings wherein:
While this disclosure is susceptible of embodiment in many different forms, there is shown in the drawings and described herein in detail a specific embodiment(s) with the understanding that the present disclosure is to be considered as an exemplification and is not intended to be limited to the embodiment(s) illustrated.
It will be understood that like or analogous elements and/or components, referred to herein, may be identified throughout the drawings by like reference characters. In addition, it will be understood that the drawings are merely schematic representations of the invention, and some of the components may have been distorted from actual scale for purposes of pictorial clarity.
Referring now to the drawings and in particular to
The pouch assembly 10 is shown in
The film 100 comprises a film that can be utilized to form the pouch 12 of the pouch assembly 10. Referring now to
In the configuration shown, layer 110 comprises the outside layer in a formed pouch, such as pouch 12. The layer 110 comprises a HDPE layer, which may include other materials, such as an anti-block master batch and a PPA master batch. In one configuration, the layer comprises 98% HDPE, 1% anti-block master batch and 1% PPA master batch. The anti-block master batch may comprise 50% LDPE and 50% diatomaceous earth. The PPA master batch may comprise 98% LLDPE and 2% fluropolymer based processing additive. Such additives may be used for a multitude of different properties, and other additives are contemplated. The particular additives are utilized to improve the characteristics for blown film production.
The layer 112 comprises a 100% HDPE layer. In certain configurations, such a layer may comprise a plurality of layers, each of which comprises an HDPE material. The layer 114 comprises a 100% LLDPE tie layer. The layer 116 comprises a 29 mol % ethylene EVOH material, and will be defined as the EVOH layer. The EVOH layer has an inside and an outside. The outside facing the layers on one side of the EVOH layer (i.e., the layers 110, 112 and 114). The inside facing the layers on the opposite side of the EVOH material (i.e., the layers 118, 120 and 122). As the EVOH layer comprises the central layer, as there are PE layers on either side thereof (one or more of LLDPE and HDPE). Preferably, the EVOH layer comprise one of Sum and 10 um, while a range of between 3 um and 15 um are contemplated.
The layer 118 comprises a 100% LLDPE tie layer. Such a layer may comprise the same material as the layer 114. It will be understood that the tie layers improve the adhesion between the EVOH layer 116 and the HDPE layers on either side thereof.
The layer 120 comprises a 100% HDPE layer. Such a layer may be identical to or may be different from the layer 112. The layer 122 comprises 53% LLDPE/43% mPE/5% anti-block master-batch/1% PPA master-batch. The anti-block master-batch and the PPA master-batch may be similar to or identical to that set forth above with respect to the layer 110. The layer 122 represents the inner surface of the pouch 12 when formed, and thus is defined as the inner LLDPE layer.
In the configuration shown, the HDPE has a density which is greater than 0.94 g/cc, and, preferably approximately 0.962 g/cc. This may be utilized for layers 112 and 120. The LLDPE has a density which is less than 0.93 g/cc, and preferably approximately 0.921 g/cc. This may be utilized for each of the layers 114, 118 and 122. The mPE has a density which is less than 0.92 g/cc, and more preferably approximately 0.911 g/cc. The thickness of the EVOH layer is preferably between 3 um and 15 um. Additionally, the EVOH layer may be between 26 mol % and 48 mol % ethylene. The EVOH layer has a density 1.21 g/cc.
In the production of the film, it is contemplated that the thickness of the layers of PE (including the layers that are formed partially or completely from LLDPE and HDPE) on an inside of the EVOH layer 116 (i.e., layers 118, 120, and 122) are at least twice as thick as those on an outside of the EVOH layer 116 (i.e., layers 110, 112 and 114). In turn, the water vapor transmission rate WVTR on the inside of the EVOH is lower than that on the outside. Additionally, there is a greater thickness of the HDPE of layer 120 as compared to layer 110 and 112, that is a greater thickness of HDPE on the inside of the EVOH layer 116 as compared to the outside of the EVOH layer 116. Thus, as to both the thickness of the PE layer(s) and the thickness of HDPE, both are greater on the inside of the EVOH layer 116 as compared to the outside of the EVOH layer 118.
Two different examples were formed of films having the configuration in accordance with the present disclosure as set forth above. Each of the formulations were formed on a nine layer co-extruder. In such a configuration the HDPE layer 112 was split into two separate HDPE layers 112a, 112b. Similarly, the HDPE layer 120 was split into two separate HDPE layers 120a, 120b.
A first example test film was formed having the configuration generally shown in
A second example test film was formed having the configuration shown generally in
In addition to the two example test films, two comparative examples were made having formulations that had similar amounts of PE on either side of the EVOH layer and that did not have more HDPE on an inside of the EVOH layer as compared to the outside of the EVOH Layer.
The first comparative test film was formed having a configuration that was analogous to the first example test film in total thickness and the thickness of the EVOH layer 116 (5 um).
The second comparative test film was formed having a configuration that was analogous to the second example test film in total thickness (within lum) and the thickness of the EVOH layer 116 (10 um).
The samples were created and tested with respect to oxygen transmission rates. In particular, a pouch was formed from each of the above example test films and comparative test films. The test conditions are as follows:
The oxygen transmission rate was checked on a monthly basis over at least a period of 5 months, and for some films 12 months.
The graph below shows the oxygen transmission rate each month of storage, as well as the average for pouches formed from each of the comparative films in cc 100% O2/m2/day.
As can be seen from the chart above, the second example test film performed substantially better than the second comparative test film despite being of the substantially the same thickness and having substantially the same thickness of the EVOH layer 116. In fact, the oxygen transmission rate of the second example test film is less than 38% that of the second comparative test film.
Similarly, the first example test film performed substantially better than the first comparative test film despite being substantially the same thickness and having substantially the same thickness of the EVOH layer 116. In fact, the oxygen transmission rate of the first example test film is less than 43% of that of the first comparative test film.
A graph showing the results set forth above is shown in
The foregoing description merely explains and illustrates the disclosure and the disclosure is not limited thereto except insofar as the appended claims are so limited, as those skilled in the art who have the disclosure before them will be able to make modifications without departing from the scope of the disclosure.
