The present invention relates to containers for wipes, and in particular to collapsible containers for wet wipes.
A wipes container according to an exemplary embodiment of the present invention comprises: a container body comprising side walls and a bottom wall that define a container opening, the side walls h comprising pleats so that the wipes container is collapsible from a first wipes storage configuration in which the wipes container has an original height to one or more second wipes storage configurations in which the wipes container has one or more corresponding second heights that are less than the original height, a collapse force being required to collapse the container body from the original height to a fully reduced height; and a cover disposed over the container opening, the cover being sealed to the container body and comprising a lid that provides access to the container opening, the seal having a seal thickness and a seal strength, wherein the wipes container has a combination index of 200,000 or less, where the combination index is calculated based on the following equation: combination index=(collapse index) (recovery index) (moisture loss index), where collapse index=((collapse force)/(side wall thickness)) (1,000), recovery index=((1−% recovery of original height)/(side wall thickness)) (1,000), and moisture loss index=[((% moisture loss of wipes container over 20 day period)/(seal strength))+((% moisture loss of wipes container over 20 day period)/seal thickness))](10).
In an exemplary embodiment, the collapse index is within the range of 0 to 1,000.
In an exemplary embodiment, the recovery index is within the range of 0 to 20.
In an exemplary embodiment, the moisture loss index is within the range of 0 to 10.
In an exemplary embodiment, the moisture loss of the wipes container over a 20 day period is less than 6%.
In an exemplary embodiment, the seal strength is at least 10 in. of Hg.
In an exemplary embodiment, the seal thickness is within the range of 15 to 80 mils.
In an exemplary embodiment, the side walls have a thickness within the range of 10 to 40 mils.
In an exemplary embodiment, the cover has a thickness within the range of 5 to 40 mils.
In an exemplary embodiment, the collapse force is within the range of 0 to 10 lbf.
These and other features of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments.
The above and related objects, features and advantages of the present invention will be more fully understood by reference to the following, detailed description of the preferred, albeit illustrative, embodiment of the present invention when taken in conjunction with the accompanying figures, wherein:
Conventional wipes packages are susceptible to moisture loss before they reach an end user, and also after the wipes package is opened. This moisture loss may be quite substantial over time, and since one to two years may pass before wipes packages are used by a consumer, conventional wipe packages have a certain acceptable usable “shelf life” timeline. Elevated temperatures increase the level of moisture loss both before opening and after the package is opened and stored. Storing a wet wipes package for more than the “shelf life” or in an environment in which there are elevated temperatures (for example, in a hot warehouse or automobile) typically results in drying out of the wipes to an unacceptable level within the package. That is, the wet wipes within the package transform over time into non-usable “dry wipes”. Therefore, containing the most amount of moisture in the package is very important before opening and use, as well as after the package is opened.
Conventional soft packs somewhat address the “dry wipes” issue by offering a more air tight product, but the moisture retention exhibited by these types of containers are still not at the level required to achieve extended shelf life and an acceptable level of moisture during the use of the pack. Further, a conventional soft pack tends to take on a sloppy appearance as the wipe stack is reduced in height as wipes are removed from the pack.
As more clearly shown in
For comparison,
The lid 22 may be a label including adhesive that allows the label to be removed and re-applied to expose and cover the opening 20. The use of a label provides a substantially air-tight seal over the opening 20 when the container 1 is not in use. Accordingly, as shown in
As shown in
It should be appreciated that the thickness of the side walls 12 is a factor that effects the percent recovery of the container 1. If the thickness of the side walls 12 is too great, the container 1 will not provide appropriate flex to allow a user to easily reduce the height of the container 1, and if the thickness of the side walls 12 is too small, the container 1 will not retract with sufficient spring force to allow the container 1 to return to the same or approximately the same as its original height. In this regard, the thickness of the side walls 12 is preferably within the range of 10-40 mils., and the collapse force is preferably 10 lbf or less. The collapse force is determined using the test procedure described herein.
The following examples illustrate the advantages of the present invention:
A wipes container was assembled using a thermoformed tub whose sidewalls have a substantially fluted architecture with a nominal lay-flat wall thickness of 20 mils. The container tub was made from a clear polypropylene copolymer (the tub material was a sheet sourced from Spartech Corporation, located in Clayton, Mo., Product Code 120124). The tub is nominally 140 mm wide, 205 mm long, and 70 mm high. The sidewall contains 6 flutes with each flute nominally 3 mm deep (peak to valley) and 8 mm apart (valley to valley). The container's cover is a 12 mil white polypropylene (the cover material was sourced from Spartech Corporation, located in Clayton, Mo., Product Code 112734) and is 140 mm wide and 205 mm long. The cover is sealed to the tub via ultrasonic welding. There is an opening on the cover that is generally centered, oval shaped, and is nominally 32 mm long and 22 mm wide. The opening is sealed with a removable adhesive strip and a “pop-up” lid that is attached via an adhesive. The cover seal strength is 21.7 in. of Hg and has a seal thickness of 32 mils. Collapse force, recovery and percent moisture loss (over a 20 day period) were tested.
The collapse force and percent recovery were measured using the following equipment: IMADA—Force Gauge DPS-44R; Vertical Manual Lever Test Stand; Large Plate Attachment for Force Gauge.
The following steps were performed to determine collapse force:
1) Affix the large plate attachment to the force gauge.
2) Affix the gauge to the vertical manual lever test stand.
3) Turn on the power for the force gauge.
4) Adjust the height of the force gauge on its stand to allow the container being tested to fit directly under the large plate and touching the large plate with zero pressure.
5) Press the “zero button” on the gauge to reset the gauge reading to zero.
6) Press the “peak button” on the gauge to enable the gauge to measure the peak force to collapse a container.
7) Pull down on the lever to compress the container completely (“completely down”).
8) While maintaining the lever in the “completely down” position, record the peak force on the gauge (the collapse force) and prepare for the recovery force test.
The following steps were performed to determine recovery force:
1) With the lever in the “completely down” position, press the “zero button” to reset the gauge reading to zero.
2) Press the “peak button” to enable the gauge to measure the peak force of recovery of a container.
3) Release the lever and let the collapsed container push back upward on the gauge.
4) Record the peak force on gauge (the recovery force).
Recovery force was determined as follows:
1) With the lever in the “completely down” position, press the “zero button” to reset the gauge reading to zero.
2) Press the “peak button” to enable the gauge to measure the peak force of recovery of a container.
3) Release the lever and let the collapsed container push back upward on the gauge.
4) Record the peak force on gauge (the recovery force).
Recovery percentage was determined as follows:
1) Prior to conducting the Collapse Force test procedure, measure and record the initial height of the container.
2) Conduct the Collapse Force test procedure.
3) Conduct the Recovery Force test procedure.
4) Upon completion of the Recovery Force test, measure the “recovered height” of the tested container and record.
5) To calculate the Recovery Percentage apply the following formula:
(Recovered Height/Initial Height)*100=Recovery Percentage
Percent moisture loss was measured using the following equipment: Scale: AND GF-4000; and VWR Model: 1565 Incubator. The following steps were performed:
1) Condition the incubator. Set incubator temperature to 55° C.
2) Determine the initial weight(s). Using a scale, weigh a sample(s) of a stack of wet wipes sealed in its packaging (i.e., tub, soft pack, etc.) and record the result(s).
3) Accelerate Age the Sample(s). Place the sample(s) in the incubator that has achieved 55° C.
4) Evaluate for Moisture Loss. Re-weigh the sample(s) every other week day and record the results (Monday, Wednesday, and Friday). Repeat for a period of 20 days to obtain 10 data points.
5) Calculate the Weight Loss. Use the following formula: [(Initial Weight−Re-Weighed Weight)/Initial Weight]*100=Moisture Loss %
A standard hard wipes container (without accordion pleats) was provided with a side wall thickness of 31 mils, a cover thickness of 38 mils, a snap-on seal strength of 0.5 in. of Hg and a seal thickness of 69 mils (since the standard hard wipes container includes a removable cover, any sealing is achieved through the snap fit connection between the cover and the side walls). The container was subjected to the same test procedures described in Example 0.
A hard wipes container commercialized by Proctor & Gamble under the Pampers brand (UPC no. 0-37000-28248-8) was provided. The Pampers wipes container has a side wall thickness of 36 mils, a cover thickness of 40 mils, a snap on seal strength of 0.5 in. Hg and a seal thickness of 76 mils (since a hard wipes container includes a removable cover, any sealing is achieved through the snap fit connection between the cover and the side walls). The container was subjected to the same test procedures described in Example 0.
A wipes container commercialized by Kimberly Clark under the Huggies brand (UPC no. 0-36000-12110-0) was provided. The Huggies wipes container has a side wall thickness of 40 mils, a cover thickness of 32 mils, a snap on seal strength of 1.3 in. of Hg and a seal thickness of 72 mils (since a hard wipes container includes a removable cover, any sealing is achieved through the snap fit connection between the cover and the side walls). The container was subjected to the same test procedures described in Example 0.
A soft pack wipes container was provided having a side wall thickness of 2.5 mils, a cover thickness of 2.5 mils, a seal strength of 16.4 in. of Hg and a seal thickness of mils. The container was subjected to the same test procedures described in Example 0.
A soft pack wipes container commercialized by Proctor & Gamble under the Pampers brand (UPC no. 0-37000-50197-8) was provided. The Pampers soft pack has a side wall thickness of 3 mils, a cover thickness of 3 mils, a seal strength of 22 in. of Hg and a seal thickness of 6 mils. The container was subjected to the same test procedures described in Example 0.
A soft pack wipes container commercialized by Kimberly Clark under the Huggies brand (UPC no. 0-36000-11692-2) was provided. The Huggies soft pack has a side wall thickness of 2 mils, a cover thickness of 2 mils, a seal strength of 19.1 in. of Hg and a seal thickness of 4 mils. The container was subjected to the same test procedures described in Example 0.
The results of these tests are shown in Table 1 below:
In-use moisture loss was also tested for Example 0 and Comparative Examples CE1-CE6 using an AND GF-4000 scale and performing the following steps:
1) Condition the test samples at ambient temperature (approximately 70° F.) for a minimum of 2 hours.
2) Determine the Initial Stack Weight(s): Weigh the full stack of wipes, inside its original sealed packaging, on the scale and record the initial stack weight
3) Open the package and ready the product for use as per the instructions on the package.
4) Determine the Beginning Wipe Average Weight(s): Individually remove the 1st five (5) wipes from the wipes package, place them all on a scale and weigh them as a group to determine the “zero-time” weight. Record the result(s). Close the package as per the instructions on the package.
5) Determine the In-Use Average Wipe Weight(s): Every two (2) hours, up to fourteen (14) hours, individually remove five (5) wipes from the previously used package, weigh them as a group, and record the result(s). Be sure to close the package as per the instructions on the package after every measurement interval.
6) Continue to Determine the In-Use Average Wipe Weight(s): Resume testing twenty-four (24) hours after recording the Beginning Wipe Average Weight. Every two (2) hours, up to thirty-six (36) hours or until all wipes are removed from the package, individually remove five (5) wipes from the previously used package, weigh them as a group, and record the result(s). Be sure to close the package as per the instructions on the package after every measurement interval.
7) Calculate the in-use moisture loss:
Weighed Wipe Weight (in g)=Sum of all wipe weight measurements.
Moisture Lost (in g)=Initial Stack Weight (−) Weighed Wipe Weight
Moisture Lost (in %)=(Moisture Lost/Initial Stack Weight)*100=N %
Moisture Lost Difference vs. Hybrid Tub (in multiples)=Moisture Lost (in %)/Hybrid Tub Moisture Loss (in %)
Average Moisture Lost/Wipe (in g)=Moisture Lost (in g)/Wipe Count (Each)
The results of the in-use moisture loss testing are shown in Table 2 below:
The combination of features of the wipes container according to various exemplary embodiments of the present invention as summarized in Table 1 and Table 2 provide a combination of advantages that is not provided by either the conventional standard wipes container or the conventional soft pack wipes container. For example, both the standard wipes container and the inventive wipes container provide a high percent recovery so as to maintain a consistent presentation, but unlike the standard wipes container, the inventive wipes container also provides high seal strength to prevent moisture loss and allows easy access to the stored wipes by, for example, self-threading. Further, both the soft pack wipes container and the inventive wipes container retain moisture due to high seal strengths, but unlike the soft pack, the inventive wipes container provides a consistent presentation. Also, the inventive wipes container provides relatively low in-use moisture loss as compared to conventional soft and hard packs. For example, conventional hard packs exhibit approximately four times more in-use moisture loss and conventional soft packs exhibit approximately two times more in-use moisture loss as compared to the inventive wipes container.
In order to demonstrate the advantages of the present invention, various indices may be calculated that take into account percent recovery, seal strength, collapse force, side wall thickness and percent moisture loss. In this regard, a combination index may be calculated for each container using Equations 1-4, shown below:
combination index=(collapse index)(recovery index)(moisture loss index), (1)
where collapse index=((collapse force)/(side wall thickness))(1,000), (2)
recovery index=((1−% recovery of original height)/(side wall thickness))(1,000), and (3)
moisture loss index=((% moisture loss of wipes container over 20 day period)/(seal strength))+((% moisture loss of wipes container over 20 day period)/seal thickness)) (4)
The results of the combination index calculations for each of the Examples and Comparative Examples is provided below in Table 2:
In general, it is desirable for a wipes container to exhibit a relatively low collapse index with greater side wall thickness than conventional soft packs, a relatively low recovery index and a relatively low moisture loss index. Table 2 shows that the present invention exhibits a combination index that is much lower than that exhibited by other types of conventional wipes containers as a result of the relatively low collapse, recovery and moisture loss indices. In particular, the wipes container according to various exemplary embodiments of the present invention may have a combination index of less than 200,000, with a collapse index within the range of 0 to 1,000, a recovery index within the range of 0 to 20, and a moisture loss index within the range of 0 to 10.
Now that the preferred embodiments of the present invention have been shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.