Patent Application
20210053738
This invention generally relates to the field of flexible containers. More particularly, the invention relates to optionally refillable containers fabricated from flexible film and comprising a fitment, wherein the fitment is connected to the container at a sealed junction formed by the film comprising the container, such as at a neck of the container.
Flexible “stand-up” pouches and bottles for holding liquids and other pourable products are very popular. Such products are advantageous as compared to traditional containers for pourable products because, among other reasons, flexible plastic pouches and bottles help reduce solid waste and are less costly to manufacture. An early stand-up pouch design dubbed the “Doyen pouch” is described in U.S. Pat. No. 3,380,646, and it is still in use today. A well-known version of traditional Doyen pouch, at least in the United States, is the Capri Sun® juice drink pouch. Subsequent modifications of the Doyen design included installation of fitments between the two panels at the top portion of the pouch to allow the pouch to be reclosed after opening.
A major difficulty with the installation of fitments in Doyen pouches, however, (and in other pouch designs as well) is that, according to early prior art fitment sealing methods, the fitment must be of the “canoe” style to create a joint that can be reliably sealed. Canoe style fitments are illustrated in, e.g., U.S. Pat. Nos. 4,415,085, 4,732,299, and 5,660,477. The canoe type of fitment was an attempt to minimize the change in direction of pouch material as it comes into contact with the fitment. Put another way, the canoe type of fitment is designed to minimize the angle of divergence of two portions of container material that separate and move apart to envelope (and subsequently be sealed to) the fitment. In so doing, canoe style fitments improved the integrity of the joint where the two sides of the pouch come together at the fitment. However, even the use of a canoe shaped fitment does not completely solve the difficulties in sealing a fitment into a pouch, and a more reliable sealing means is desirable.
This problem was addressed in U.S. Pat. Nos. 6,832,852 and 7,147,597, both of which are incorporated herein in their entirety by reference. As shown in the '852 and '597 patents, while canoe style fitments can be used in connection with the present invention, “cylindrical base” fitments are preferred. The sealing surface of a cylindrical base style fitment is preferably substantially parallel to the axis of the fitment, as in the canoe style, but it does not include external corners at sharply acute angles around its circumference, as do canoe style fitments. Rather, in accordance with a first style of cylindrical base fitment, the circumference is preferably comprised of smooth and preferably convex curves. Having the circumference comprised of smooth curves is intended to facilitate the sealing of web material to the base of the fitment with two overlapping sealing steps applied from different directions. These sealing steps include: (i) clamping bottle material to the fitment with a heated clamping means to create a seal between the bottle material and the fitment, and (ii) clamping the bottle material to the fitment with a heated clamp a second time, the second clamping being at a different radial angle. By this method, the fitment is installed (i.e., adhered to by heat and pressure) in a neck of the bottle by way of a leakproof seal formed by the clamps.
Suitable optionally refillable flexible containers for use in connection with the present invention may be formed, by way of non-limiting example, in accordance with the disclosures of the '852 and '597 patents, as well as U.S. Pat. Nos. 8,231,029, 8,348,509, and 8,840,305, all of which are incorporated herein in their entirety by reference.
Despite the technological advancements in the art provided by the '852 and '597 patents, there remains room for an improvement to the methods and devices described therein, particularly with respect to method of the sealing of the fitment to the bottle. For example, although the two-step multi-directional sealing process for attaching a substantially cylindrical fitment to the neck of a flexible bottle has proven to be substantially reliable, the strength and integrity of the seal at the respective surfaces of the fitment and the bottle neck are enhanced by way of the improvements described herein. This is particularly important with respect to containers constructed in accordance with the '852 and '597 patents, which may be used to contain larger volumes of flowable material than what is suitable for Doyen style pouches. For example, the containers of the '852, '597, '029, '509, and '305 patents can stand up on their own at volumes of 20 liters, whereas Doyen style pouches will typically fall over and/or are very unwieldy at such large volumes, particularly where the pouches have no carrying handles. These larger volumes, which are highly desirable in the flexible container market, put higher physical stresses on the fitment and the film structure, particularly at the junction of the fitment and the film neck of the container.
For example, because fitments are often sealed to varying layers of flexible material at different locations along the circumference of a fitment, it is a challenge to apply the proper temperature, pressure, time, and location of such seals on the fitment as would otherwise help to optimize the strength and reliability of the overall seal. Thicker layers of material will typically require a greater amount of heat and pressure to cause such layers to be reliably sealed to a fitment. However, the same amount of heat and pressure may compromise the integrity of thinner layers of material to be adhered to the fitment, which may become brittle. Therefore, there remains an unmet need in the art for flexible containers fabricated from flexible film and comprising a fitment, wherein an improved seal at the junction of the flexible film and the fitment is provided.
It has been found that larger volume flexible containers of the prior art, such as those having 20 liters of water inside, can withstand the physical stresses of being dropped vertically on their base from several feet. However, when dropped on their cap (i.e., at a top portion where the fitment is typically located and connected to the cap) from 6 inches, the prior art containers may burst open at the junction of the film and the fitment at the neck of the container. This integrity imbalance in drop performance between the ability of the container to sustain drops on its base as compared to drops on its cap needs to be addressed.
The present invention meets the aforementioned unmet need by providing improved methods and devices for sealing a fitment to a flexible container, particularly in a neck of the container. Features and advantages of the present invention will become apparent upon a reading of the attached specification, in combination with a study of the drawings. While preferred embodiments of the present invention are shown and described, it is envisioned that those skilled in the art may devise various modifications of the present invention without departing from the spirit and scope of the invention.
A preferred embodiment of the present invention comprises:
A method for sealing a fitment to a flexible container comprising the steps of:
providing a flexible container formed of flexible film and having a plurality of panels, a neck configured to be connected to a fitment, and a multiseal, the multiseal comprising a top edge, a bottom edge, a plurality of sealing surfaces, and a plurality of flaps;
providing the fitment for sealing at the neck, the fitment comprising a base surface;
placing the fitment in the neck, wherein the multiseal is provided around the base surface such that the multiseal and the base surface are complementarily aligned;
providing a plurality of primary seals on the multiseal via engagement of the multiseal by a plurality of primary sealing jaws, wherein the primary sealing jaws form the primary seals at the sealing surfaces and flaps of the multiseal, wherein the sealing surfaces are sealed to the base surface and the flaps are folded toward and sealed to the sealing surfaces;
providing a plurality of secondary seals on the multiseal via engagement of the multiseal by a plurality of secondary sealing jaws, wherein the secondary sealing jaws form the secondary seals at the sealing surfaces and flaps of the multiseal, wherein the secondary seals overlap with the primary seals, and wherein the secondary seals are located substantially closer to the top edge of the multiseal than to the bottom edge of the multiseal; and
providing a plurality of tertiary seals on the multiseal via engagement of the multiseal by a plurality of tertiary sealing jaws, wherein the tertiary sealing jaws form the tertiary seals at the sealing surfaces and flaps of the multiseal, wherein the tertiary seals overlap with the primary seals and the secondary seals.
The present invention, in some preferred embodiments, provides for a substantial improvement in drop performance when the container is dropped vertically on its cap (i.e., on the fitment portion). Testing has shown that a 10 liter container provided in accordance with a preferred embodiment of the present invention and filled with water can be dropped from one meter on its cap and not rupture, whereas containers of the prior art may rupture under the same testing parameters except that the drop distance is merely 14 centimeters. This is especially important when shipping hazardous liquids in containers formed in accordance with the present invention. For example, United Nations (“UN”) testing of containers for hazardous liquids requires the container to be tested by being dropped on all sides including with the top and cap pointing downwardly and making first impact with a surface. 10 liter volume containers formed in accordance with the present invention passed UN #1760 Class 8 tests.
An advantage of the present invention is that it provides devices and methods that form a reliable and robust multiseal of flexible material at specific locations about the circumferential surface of a base of a fitment, thereby allowing greater heat and pressure to be applied as desired to multiple material layers adhered to the base of the fitment to form a leakproof seal at the multiseal, while concurrently preserving the enhanced integrity of other thinner sealed portions that require less heat and pressure to be effectively sealed to the fitment.
With reference to the figures and elements referenced herein, improved methods and devices for sealing a fitment to a flexible container are provided. It should be appreciated that the embodiments described and shown herein are exemplary in nature only and that various additional embodiments are contemplated and within the scope of the present invention.
As discussed in detail below, preferred embodiments of the present invention comprise flexible containers, such as optionally refillable bottles formed of a flexible material, such as webs of plastic film. In forming such bottles comprising a fitment sealed into a neck or other portion of the bottle, there often exists a need to seal one or more layers of the flexible material to a surface of the fitment. The process of doing so, as well as the corresponding bottle structure, provide for a robust, reliable, and preferably leak-proof seal at the juncture of the fitment and the layers of bottle material. Such seals are often critical to the endurance and utility of the containers that comprise them. This is because a rupture, such as in seals of the prior art, may result in catastrophic failure of the corresponding prior art bottle, such that bottle contents may leak or flow out of the bottle body at the ruptured seal between the fitment and bottle material, as opposed to through the installed fitment as intended. The present disclosure teaches novel and inventive improvements to such seals as applicable to a variety of flexible bottles that are suitable for use with preferred embodiments of the present invention.
Container 10 is preferably formed by coextrusion of flexible film. For example, the film comprising container 10 is preferably a film formed of a coextrusion of high-density polyethylene (“HDPE”) outer portion and a low-density polyethylene (“LDPE”), or linear low density polyethylene (“LLDPE”) inner sealant portion. In this example, the outer HDPE portion of the film is preferably approximately 3 mils thick, and the LDPE or LLDPE inner sealant portion of the film is preferably approximately 7 mils thick. Therefore, in preferred embodiments of the present invention, the film comprising container 10 is preferably approximately 10 mils thick. The film comprising container 10 may be formed of a single coextruded film comprising HDPE and LDPE or LLDPE portions, or one or more layers of coextruded film coupled with one or more layers of film that may or may not be coextruded. For example, in an alternative embodiment, the container 10 comprises two separate layers of film, wherein an outer layer is a coextrusion of HDPE and LDPE film that is preferably approximately 10 mils thick (consistent with the above description of such a layer) and an inner layer of LDPE that is preferably approximately 4 mils thick.
In an embodiment, container 10 is formed from a coextruded multilayer film wherein each layer is composed of polyethylene. A coextruded multilayer film wherein each layer is composed of a polyethylene is interchangeably referred to as an “all-polyethylene” film.
In an embodiment, container 10 is formed from an all-polyethylene film that is a five layer film. The five layer film has the following layer structure: HDPE(skin)/LLDPE/LLDPE/LLDPE/polyolefin plastomer (seal).
As further shown in
Other devices and methods for forming the flexible container 10 prepared for the installation of the fitment 40 as provided in accordance with the present invention may be suitable for use with the present invention, as will be appreciated by those of ordinary skill in the art. In most, if not all such devices and methods, there will preferably exist a step whereby material comprising the flexible container 10 will be made adjacent to the body of the fitment 40, such as at the neck 30 of the container 10 where the fitment 40 is be installed, and one or more layers of the material will be sealed, often by heat and pressure, to the fitment base 41 to form a robust and reliable seal intended to unite the fitment 40 and the container 10.
For example,
A. Multiseal Process Step 1
In Multiseal Process Step 1, sealing jaws 210 enclose the fitment 40 to form primary seals 130, 131.
As will be appreciated by those of ordinary skill in the art, such sealing parameters listed herein correspond to the constituent materials and methods described herein with respect to the preferred embodiment of container 10. Accordingly, such parameters in the various steps of the Multiseal Process may be amended to accommodate the sealing of alternative embodiments of the present invention, such as embodiments comprising different thicknesses and material compositions of the film, as well as different container sizes and corresponding fitments.
As further shown in
Consequently, as best shown in
As shown in
As shown in
B. Multiseal Process Step 2
In Multiseal Process Step 2, sealing jaws 220 enclose the fitment 40 to form secondary seals 140, 141, 142, 143, which overlap with the primary seals 130, 131.
As shown in
Consequently, as best shown in
As shown in
As best shown in
As previously discussed, a particular benefit of the reduced size and particular location of the secondary seals 140, 141, 142, 143 is that additional heat may be applied to reinforce the sealing of the flaps 110 to the fitment 40 where the thickness of the film is greater. It is also advantageous to apply the secondary seals 140, 141, 142, 143 nearer to the top base edge 43 so as to mitigate the possibility that single layer portions of the multiseal 100 may be made brittle or unreliable in view of the enhanced heat toward the bottom base edge 44, where the pressure among the junction of the neck 30 and the fitment 40 is often the greatest and where most ruptures tend to occur in prior art containers.
C. Multiseal Process Step 3
In Multiseal Process Step 3, sealing jaws 230 enclose the fitment 40 to form tertiary seals 150, 151, which overlap with the primary seals 130, 131 and secondary seals 140, 141, 142, 143.
As shown in
As shown in
As best shown in
It is contemplated that a greater or lesser number of jaws may be used. For example, jaws 220 may be a pair of complementary jaws 220 instead of four jaws 220, wherein a gap is machined between pairs of sealing faces 222 such that although jaws 220 are two instead of four, preferably four secondary seals 140, 141, 142, 143 are still imparted on the multiseal 100.
It is contemplated that extra steps of the Multiseal Process may be employed. For example, a Multiseal Process Step 4 comprising a repeat of Multiseal Process 1 for a one second dwell smooths out surface indents that may be imparted on the multiseal 100 by jaws 220 during the higher pressure and temperature Multiseal Process Step 2.
It is contemplated that the previously described multiseal process step 1, utilizing sealing jaws 210 (and hereafter “sealing step 1”), multiseal process step 2, utilizing sealing jaws 220 (and hereafter “sealing step 2”), and multiseal process step 3, utilizing sealing jaws 230 (and hereafter “sealing step 3”) may be employed in different sequential orders. For example, the multiseal sealing sequence can be sealing step 1 followed by sealing step 2, followed by sealing step 3. Alternatively, the multiseal sealing sequence can be sealing step 1 followed by sealing step 3, followed by sealing step 2.
In an embodiment, container 10 is formed from a five layer all-polyethylene film and container 10 has one, some, or all of the following properties:
(i) passes the burst test at 18 mm Hg; and/or
(ii) passes the top drop test; and/or
(iii) exhibits a fitment-to-neck seal interface that is smooth and free of defects.
By way of example, and not limitation, examples of the present disclosure are provided.
Four panel flexible containers having a neck (with no fitment) and a body as shown in
+Antiblock = Silica Masterbatch (20% Diatomaceous Earth + 80% Dow LDPE 722))
# Erucamide Masterbatch (5% Slip + 95% Dow LDPE 722)
Density is measured in accordance with ASTM D 792.
Melt index (MI) is measured in accordance with ASTM D 1238, Condition 190° C./2.16 kg (g/10 minutes).
Four panels made from the flexible multilayer film in Table 1 are heat sealed together under the heat seal conditions provided in Table 2 (below) to produce flexible container blanks (i.e., a “blank” being a flexible container without a fitment). The four-sided flexible containers have the geometry and design of the flexible containers as shown in
A fitment with a base diameter of 41 mm is inserted into the neck for each respective flexible container. Each fitment is made from the same high density polyethylene (HDPE). A 38 mm diameter mandrel inserted into the base of the fitment. The mandrel includes an expandable collar. The expandable collar is made of Shore A 30+/−5 durometer FDA approved silicone rubber.
With the mandrel inserted in the base, and the collar expanded, the base of the fitment is heat sealed to the neck of the flexible container using sealing jaws 210, 220, 230 as shown in
The flexible container with fitment sealed thereto is evaluated for burst test, top drop test, and seal appearance. The procedure for the burst test and the procedure for the top drop test are provided below.
Burst Test Procedure
Process:
Top Drop Test
Each flexible container is filled with 3800 grams of water was held by bottom handle with the cap directly aligned to the drop surface. The distance is measured from the cap to the drop surface. The drop surface is smooth concrete. Data was only collected from samples where the cap struck the drop surface first. Failure is defined as any leakage of the package after dropping.
The results for the burst test, the top drop test, and seal appearance are provided in Table 3 below.
Applicant discovered that the present three step multiseal process utilizing sealing jaws 210, 220, and 230 unexpectedly enables a reduction in heat seal temperature during heat sealing, thereby enabling an all-polyethylene film to be used for the flexible container. The present multiseal process with sealing jasws 210, 220, 230 eliminates the need for a polyamide skin layer or a polyester skin layer, typically required to provide heat resistance during the heat sealing procedure. A flexible package made from an all-polyethylene multilayer film is advantageous for processability (multilayer film with all-polyethylene layers is co-extrudable and does not require a lamination step). Another benefit of an all-polyethylene film is its recyclability.
It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come with the scope of the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/029326 | 4/26/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62663157 | Apr 2018 | US |
