US20080057245A1

US20080057245A1 - Liquid Container Material And Method Thereof

Info

Publication number: US20080057245A1
Application number: US11/469,211
Authority: US
Inventors: Dale Bennett; Robert Flaherty; Shawn Sharp
Original assignee: Berry Plastics Corp
Current assignee: Berry Global Inc
Priority date: 2006-08-31
Filing date: 2006-08-31
Publication date: 2008-03-06

Abstract

Embodiments of the present invention include a method for making a non-wicking liquid container material comprising providing container stock material having a first side and a second side, applying a first layer of thermoplastic material to the first side of the container stock material, compressing the container stock material such that the first layer of thermoplastic material is pressed substantially through a portion of the container stock material, applying a second layer of thermoplastic material to the first side of the container stock material, and applying a layer of foam material to the first side of the container stock material.

Description

BACKGROUND

1. Field of the Invention
Embodiments of the present invention generally relate to material used to make liquid containers, and more specifically, to a split-coat material that substantially minimizes wicking of liquid through the material, and a method of making the material.
2. Description of the Related Art
Certain containers for holding liquids, e.g., liquids, comprise at least one layer of paper material on the exterior and a layer of foam material on the interior. The foam material is used to inhibit heat transfer of a hot liquid to the exterior or insulate cold liquid from the exterior of the container. Often, the paper material is laminated to the foam material using a thermoplastic material. However, often the contained liquid seeps or wicks through the foam material into the paper material, thereby making the cup unsightly and unusable.
Thus, it is desired to have a material for making containers that substantially inhibits a contained liquid from wicking through the layers of the container.

SUMMARY

An embodiment of the present invention includes a method comprising providing container stock material having a first side and a second side, applying a first layer of thermoplastic material to the first side of the container stock material, compressing the container stock material such that the first layer of thermoplastic material is pressed substantially through a portion of the container stock material, applying a second layer of thermoplastic material to the first side of the container stock material, and applying a layer of foam material to the first side of the container stock material.
Another embodiment of the present invention includes a method comprising providing container stock material having a first side and a second side, applying a liquid primer to the first side of the container stock material, applying a first layer of thermoplastic material to the first side of the container stock material, compressing the container stock material such that the first layer of thermoplastic material is pressed substantially through a portion of the container stock material, applying a liquid primer to the second side of the container stock material, applying a second layer of thermoplastic material to the second side of the container stock material, applying a third layer of thermoplastic material to the first side of the container stock material, and applying a layer of foam material to the first side of the container stock material.
Another embodiment of the present invention includes a method comprising providing container stock material having a first side and a second side, applying a liquid primer to the first side of the container stock material, compressing the container stock material such that the liquid primer is pressed substantially through a portion of the container stock material, applying a first layer of thermoplastic material to the first side of the container stock material, and applying a layer of foam material to the first side of the container stock material.
In yet another embodiment of the present invention, a liquid container material comprises a layer of container stock material comprising a first side and a second side, a first layer of thermoplastic material applied to the first side of the layer of container stock material, wherein the first layer of thermoplastic material is compressed substantially through a portion of the layer of container stock material, and a layer of foam material applied to the first side of the layer of container stock material, wherein the at least one foam layer is applied with a second layer of thermoplastic material, is provided.
Another embodiment of the present invention includes a liquid container material, comprising a layer of container stock material comprising a first side and a second side, a first layer of thermoplastic material applied to the first side of the layer of container stock material, wherein the first layer of thermoplastic material is compressed substantially through a portion of the layer of container stock material, a second layer of thermoplastic material applied to the second side of the layer of container stock material, and a layer of foam material applied to the first side of the layer of container stock material, wherein the at least one foam layer is applied with a third layer of thermoplastic material.
In yet another embodiment of the present invention, a liquid container material, comprising a layer of container stock material comprising a first side and a second side, a liquid primer applied to the first side of the layer of container stock material, wherein the liquid primer is compressed substantially through a portion of the layer of container stock material, and a layer of foam material applied to the first side of the layer of container stock material, wherein the at least one foam layer is applied with a layer of thermoplastic material, is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate a manufacturing system for making a substantially non-wicking liquid container material, in accordance with an embodiment of the present invention;

FIG. 2 illustrates a method for making a substantially non-wicking liquid container material, in accordance with an embodiment of the present invention; and

FIG. 3 is a cross-sectional view of a substantially non-wicking liquid container material, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

FIGS. 1A and 1B depict a dual-pass manufacturing system for making a substantially non-wicking liquid container material. Although the embodiments illustrate a process of making the container material using two passes on the same system, the scope of the invention encompasses embodiments making the material using less than two passes or more than two passes on different manufacturing systems.
As shown in FIG. 1A, a first pass of a container stock material on a system 100 for making a substantially non-wicking liquid container material comprises placing a roll of the base container stock material 102, such as, for example, 18-point bleached base paper material, onto a turn bar. The container stock material 102 may have a rough side 104 and a smooth side 106, where the smooth side 106 will become the exterior surface of a liquid container made from the resulting liquid container material.
The container stock material 102 may be a pre-wound roll that can be unwound using system 100 and pulled into a first extruder station comprising an extruder 112 and two rollers 108 and 110. A melted thermoplastic material 116 is extruded onto the rough side 104 through the extruder 112. The rollers 108 and 110 may be made of, or lined with, rubber, chrome, or any material typically used in such manufacturing systems to facilitate movement of the container stock material 102 through the rollers 108 and 110. The roller 108 is made of, or lined with, rubber. The roller 110 is made of, or lined with, chrome such that the smooth side 106 of the container stock material 102 rolls over the rubber roller 108 into a space between the rollers 108 and 110. This space is referred to herein as the “nip.” The rough side 104 of the container stock material rolls against the chrome roller 110 as the melted thermoplastic 114 is extruded onto the rough side 104.
The thermoplastic material 114 may be any thermoplastic material, such as, but not limited to polyethylene polymers, polypropylene polymers, and the like. The polyethylene polymers may include, but are not limited to, linear low density polyethylene, low density polyethylene, medium density polyethylene, and high density polyethylene. Preferably, the rough side 104 is coated with about 6 lbs/3000 square feet to about 15 lbs/3000 square feet of a polyethylene polymer. A nip pressure is set to a value such that the extruded thermoplastic 114 is pressed substantially through the thickness of the container stock material 102. The pressure may be set to a value between about 20 pounds per square inch (“psi”) and about 120 psi. The thermoplastic 114 pressed through the rough side 104 of container stock material 102 functions as both a barrier to wicking of a contained liquid through the container material, and an adhesion primer for application of an additional layer of material to the container stock material 102.
Another embodiment of the present invention includes setting a nip pressure between the rubber roller 108 and the chrome roller 110 between about 60 psi and about 80 psi to drive the thermoplastic 114 through the container stock material 102. A preferred embodiment of the present invention includes extruding a coat of 6 lbs/3000 square feet of low density polyethylene from extruder 112 onto the rough side 104 of the container stock material 102 and setting a nip pressure to about 72 psi to press the thermoplastic material 114 through the container stock material 102.
The container stock material 102 then is pulled into to a second extruder station of the system 100 comprising extruder 120 and two rollers 116 and 118. The rollers 116 and 118 are made of, or lined with, chrome and rubber, respectively. The coated rough side 104 runs against the chrome roller 116 before being pulled into the nip of the chrome roller 116 and the rubber roller 118. A melted thermoplastic material 122 is extruded onto the smooth side 106 of the container stock material 102. Preferably, the smooth side 106 is coated with about 6 lbs/3000 square feet to about 15 lbs/3000 square feet of a polyethylene polymer. The nip pressure may be set to a value between about 20 psi and about 120 psi. The container stock material 102 now is coated on both the rough side 104 and the smooth side 106.
Another embodiment of the present invention includes setting a nip pressure between the chrome roller 116 and the rubber roller 118 between about 60 psi and about 80 psi. A further embodiment of the present invention includes extruding a coat of 7.2 lbs/3000 square feet of medium density polyethylene from extruder 120 onto the smooth side 106 of the container stock material 102 and setting a nip pressure to about 72 psi.
In another embodiment of the present invention, the container stock material 102 does not pass through a second extruder station and the smooth side 106 does not receive a layer of melted thermoplastic material 122, but, instead, remains uncoated.
The container stock material 102 then may be pulled over a series of turn bars 124 and 126. The container stock material 102 then may enter a corona treating station 128 while being pulled over turn bars 130. The corona treating station 128 treats the extruded thermoplastic on the smooth side 106 to facilitate applications of printing ink that may be applied to the smooth side 106. The container stock material 102 then is pulled over turn bars 132 and 134 to be wound into a roll 136.
FIG. 1B depicts a second pass of the container stock material 102. The material 102 is unwound from the roll 136 and pulled into an extruding station comprising an extruder 146 and two rollers 142 and 144. The roller 142 is made of, or lined with, rubber. The roller 144 is made of, or lined with, chrome to facilitate movement of the container stock material 102. The container stock material 102 is pulled through a nip between the rollers 142 and 144, such that the coated smooth side 140 of the container stock material rolls over the rubber roller 142, and the coated rough side 138 of the container stock material 102 is pulled against the chrome roller 144.
A melted thermoplastic material 148 is extruded onto the coated rough side 138 via the extruder 146. The melted thermoplastic functions as an adhesive to a layer of foam material 150 that is pulled into the nip between the two rollers 142 and 144. The layer of foam material 150 adheres to the coated rough side 138 of the container stock material 102. The foam material 150 may be made from polyethylene polymers, polystyrene, or any material suitable for liquid containers. An example of a foam material is AF030, available by Pactiv Corporation. The foam material 150 adheres to the coated rough side 138 by a lamination process using a coat of 6 lbs to about 15 lbs/3000 square feet of an extruded polyethylene polymer. In an embodiment, a coat of 6 lbs/3000 square feet of medium density polyethylene is extruded onto the coated rough side 138 to adhere the foam material 150.
To prevent crushing of the foam layer 150, the rollers 142 and 144 may be spaced a distance apart, creating a nip. Preferably, this nip is between about 28 millionths of an inch (“mils”) and about 50 mils. However, to securely affix the foam layer 150 to the container stock material 102, a nip pressure may be set to a value between about 20 psi and about 60 psi. A strong and efficient bond between the foam layer 150 and the coated rough side 138 is achieved due to the thermoplastic coat previously extruded onto the rough side 104 during the first pass described in FIG. 1A. Another embodiment of the present invention utilizes a nip of 34 mils between the rollers 142 and 144 and a nip pressure of 42 psi to adhere the foam layer 150 to the container stock material 102 without crushing the foam layer 150.
The laminated container stock material 152 then passes through an extruder section comprising two rollers 154 and 156 and an extruder 158. The coated smooth side 140 passes over the roller 154, which is made of, or lined with, rubber while the foam material 150 is pulled against the roller 156, which is made of, or lined with, chrome. Substantially simultaneously, a melted thermoplastic material 160 is extruded onto the foam material 150 from the extruder 158. The melted thermoplastic material 160 may be a polyethylene polymer, a polypropylene polymer, or any thermoplastic material suitable for use in liquid container material. The polyethylene polymers may include, but are not limited to, linear low density polyethylene, low density polyethylene, medium density polyethylene, and high density polyethylene.
In another embodiment, the foam material 150 is coated with about 10 lbs/3000 square feet to about 20 lbs/3000 square feet of a melted polyethylene polymer. To prevent the foam material 150 from being crushed by the rollers 152 and 154, the rollers 152 and 152 may be spaced a distance apart. Preferably, this nip is between about 28 mils to about 50 mils. The laminated container stock material 152 then is pulled over a turn bar 162 and wound into a roll 164 ready for further processing.
An embodiment of the present invention utilizes a nip of 30 mils between the rollers 154 and 156 as a coat of 11 lbs/3000 square feet of low density polyethylene is extruded onto the foam side 150 of the laminated container stock material 152.
In another embodiment of the present invention, the foam material 150 is pre-coated with a liquid-barrier or liquid-impermeable material that minimizes wicking of a contained liquid. In this embodiment, the laminated stock material 152 does not pass through an extruder section and melted thermoplastic material 160 is not applied to the foam material 150. Another embodiment of the present invention comprises pre-coating the foam material 150 with a material selected from the group consisting of acrylic-based coatings, polyvinyl alcohol coatings, and solvent-based primers.
Another embodiment of the present invention comprises applying a liquid primer, such as a water-based liquid solution, for example, polyethyleneimine, to each side of a container stock material to facilitate receiving the first coat of the melted thermoplastic material prior to the application of the layer of foam material. The liquid primer may be applied using a gravure roller. Examples of a liquid primer that may be used include, but are not limited to, MICA 131X (Mica Corp.), ADCOTE 1544 (Rohm & Haas), and the like.
FIG. 2 illustrates steps in a process flow describing an embodiment of the present invention. The steps need not necessarily be in the sequence illustrated, and some of the steps may occur essentially simultaneously. A process 200 begins at step 202. At step 204 a container stock material is unwound and a layer of thermoplastic material is applied to a first side of the container stock material. The container stock material may be any material suitable for use in a liquid container, and preferably is a paper base material. The thermoplastic material may be applied by extrusion coating, extrusion lamination, and other like processes. Preferably, the thermoplastic material is a polyethylene polymer, such as low density polyethylene. The polyethylene is applied to a first side of the container stock material, where the first side will face the interior of a liquid container made from the container stock material.
At step 206, a pressure is applied to the container stock material to press the applied thermoplastic material substantially through the thickness of the material. Preferably, a nip pressure of about 72 psi is applied to the container stock material. However, other embodiments of the present invention comprise applying a nip pressure between about 20 psi and about 120 psi to press the thermoplastic material through the container stock material. Pressing the thermoplastic material substantially through the material substantially minimizes wicking of a contained liquid through a portion of the container material. It also functions as an adhesion primer for additional materials to be applied to the container stock material.
At step 208, another layer of a thermoplastic material is applied to a second side of the container stock material, thereby coating both sides of the container stock material with thermoplastic material and further minimizing wicking of a contained liquid. As shown in step 208, a coating of a polyethylene polymer, such as a medium density polyethylene, is applied by an extrusion process onto the second side of the container stock material. As discussed in step 204, the thermoplastic material is not limited to polyethylene, but may be any thermoplastic material suitable for use with liquid container materials.
At step 210, a second layer of a thermoplastic material is applied to the coated first side of the container stock material. Preferably, the thermoplastic material is a polyethylene polymer, such as medium density polyethylene, although the scope of the invention encompasses embodiments using any thermoplastic material suitable for use with liquid container materials. The polyethylene is applied using an extrusion coating process, but may be applied using extrusion lamination, and other well known processes.
In step 210, this second application of the thermoplastic material to the coated first side of the container stock material functions to adhere a layer of a foam material to the coated first side of the container stock material. The foam material may be made from polyethylene, polystyrene, and the like, and may be applied using a well known lamination process. To secure the bond between the foam material and the container stock material, a pressure between about 20 psi and about 60 psi may be applied. Preferably, a pressure of 42 psi is applied to the foam material and the container stock material, as shown in step 210. The foam material combined with the container stock material produces a laminated material.
In step 212, the exposed foam side of the laminated material is coated with a thermoplastic material to prevent a contained liquid from substantially wicking into the laminated material. The thermoplastic material may be any material suitable for use with liquid containers, such as polyethylene polymers, polypropylene polymers, and the like, and may be applied using an extrusion coating process, an extrusion lamination process, or other like processes. As shown in step 212, a layer of polyethylene is extruded onto the exposed foam side of the laminated material.
In step 214, the laminated material then may be wound into a roll for further processing. The process ends at step 216.
Another embodiment of the present invention comprises applying a liquid primer to the first side of the container stock material prior to the first layer of thermoplastic material in step 204, as shown in step 218. The liquid primer further enhances the bond between the foam material and the container stock material and further reduces wicking of a liquid through the container material. The liquid primer also may be applied to the second side of the container stock material as shown in step 220, prior to the application of the layer of thermoplastic material in step 208, wherein the liquid primer enhances the bond of the layer of thermoplastic material applied in step 208 to the second side. The liquid primer may be any material suitable for use with container materials, such as the water-based solution ADCOTE 1544 (available by Rohm&Haas), and the like.
FIG. 3 depicts a cross-section of a substantially non-wicking liquid container material 300, according to an embodiment of the present invention. A container stock material 302 is coated on each side with a layer of thermoplastic material 304 and adhered to a foam material 306. The exposed surface of the foam material 306 is coated with a thermoplastic material 304 as well. Further, a thermoplastic material 304 is pressed substantially through a portion of the container stock material 302 as shown at 308, to substantially minimize wicking of a contained liquid through the container material 300.
Another embodiment of the present invention includes applying a liquid primer to a first side of a layer of container stock material and driving the liquid primer substantially through the container stock material by compressing the material at a nip pressure between about 20 psi and about 120 psi. A layer of foam material is applied to the first side of the container stock material using a layer of thermoplastic material. One embodiment of the present invention further comprises applying a layer of thermoplastic material to the foam layer opposite the container stock material to further minimize a wicking effect. Another embodiment comprises applying a non-thermoplastic liquid-impermeable material to the foam layer opposite the container stock material, such as, for example, an acrylic-based coating, a polyvinyl alcohol coating, or a solvent-based primer. Another embodiment further comprises applying a liquid primer to the second side of the layer of container stock material, drying the liquid primer, and applying a layer of thermoplastic material to the second side of the layer of container stock material. The liquid primer may be any primer suitable for use with liquid containers, such as, for example, a water-based solution, such as ADCOTE 1544. The thermoplastic material may be any material suitable for use with liquid containers, such as polyethylene polymers, polypropylene polymers, and the like, and may be applied using an extrusion coating process, an extrusion lamination process, or other like processes.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the present invention may be devised without departing from the basic scope thereof.

Claims

1. A method, comprising:

providing container stock material having a first side and a second side;

applying a first layer of thermoplastic material to the first side of the container stock material;

compressing the container stock material such that the first layer of thermoplastic material is pressed substantially through a portion of the container stock material;

applying a second layer of thermoplastic material to the first side of the container stock material; and

applying a layer of foam material to the first side of the container stock material.

2. The method of claim 1, wherein compressing the container stock material such that the first layer of thermoplastic material is pressed substantially through a portion of the container stock material further comprises applying a pressure between about 20 psi and about 120 psi.

3. The method of claim 1, wherein compressing the container stock material such that the first layer of thermoplastic material is pressed substantially through a portion of the container stock material further comprises applying a pressure between about 60 psi and about 80 psi.

4. The method of claim 1, wherein compressing the container stock material such that the first layer of thermoplastic material is pressed substantially through a portion of the container stock material further comprises applying a pressure of about 72 psi.

5. The method of claim 1, wherein applying the first layer and the second layer of thermoplastic material comprises extrusion coating the container stock material.

6. The method of claim 1, further comprising applying a third layer of thermoplastic material to an exposed side of the layer of foam material.

7. The method of claim 6, wherein applying the third layer of thermoplastic comprises extrusion coating the exposed side of the layer of foam material.

8. The method of claim 1, wherein applying the layer of foam material to the container stock material comprises laminating the at least one layer of foam material to the layer of container stock material.

9. The method of claim 8, wherein laminating the layer of foam material to the container stock material comprises pulling both layers between two rollers having a nip such that the layer of foam material is not substantially compressed.

10. The method of claim 9, wherein the nip is between about 28 mils to about 50 mils.

11. The method of claim 9, wherein the nip is about 34 mils.

12. The method of claim 1, wherein applying the layer of foam material to the container stock material comprises extruding the layer of foam material to the container stock material.

13. The method of claim 1, further comprising applying a liquid primer to the first side of the container stock material prior to applying the first layer of thermoplastic material.

14. The method of claim 13, further comprising applying the liquid primer using a gravure roller.

15. The method of claim 1, further comprising applying a third layer of thermoplastic material to the second side of the container stock material.

16. The method of claim 15, further comprising applying a liquid primer to the second side of container stock material prior to applying the third layer of thermoplastic material.

17. A method, comprising:

providing container stock material having a first side and a second side;

applying a liquid primer to the first side of the container stock material;

applying a liquid primer to the second side of the container stock material;

applying a second layer of thermoplastic material to the second side of the container stock material;

applying a third layer of thermoplastic material to the first side of the container stock material; and

18. The method of claim 17, further comprising applying a fourth layer of thermoplastic material to an exposed side of the layer of foam material.

19. A method, comprising:

providing container stock material having a first side and a second side;

applying a liquid primer to the first side of the container stock material;

compressing the container stock material such that the liquid primer is pressed substantially through a portion of the container stock material;

applying a first layer of thermoplastic material to the first side of the container stock material; and

20. The method of claim 19, further comprising

applying a liquid primer to the second side of the container stock material; and

applying a second layer of thermoplastic material to the second side of the container stock material.

21. The method of claim 19, further comprising applying a third layer of thermoplastic material to an exposed side of the layer of foam material.

22. A liquid container material, comprising:

a layer of container stock material comprising a first side and a second side;

a first layer of thermoplastic material applied to the first side of the layer of container stock material, wherein the first layer of thermoplastic material is compressed substantially through a portion of the layer of container stock material; and

a layer of foam material applied to the first side of the layer of container stock material, wherein the at least one foam layer is applied with a second layer of thermoplastic material.

23. The liquid container material of claim 22, further comprising a third layer of thermoplastic material applied to the second side of the layer of container stock material.

24. The liquid container material of claim 22, further comprising a third layer of thermoplastic material applied to an exposed side of the layer of foam material.

25. The liquid container material of claim 22, further comprising a layer of non-thermoplastic liquid-impermeable material applied to an exposed side of the layer of foam material.

26. The liquid container material of claim 25, wherein the non-thermoplastic liquid-impermeable material is selected from the group consisting of acrylics, polyvinyl alcohol, and solvent-based primers.

27. The liquid container material of claim 22, wherein the thermoplastic material is a polyethylene polymer.

28. The material of claim 26, wherein the polyethylene polymer is selected from the group consisting of linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene.

29. The liquid container material of claim 22, wherein the thermoplastic material comprises a polypropylene polymer.

30. The liquid container material of claim 22, wherein the layer of foam material comprises a polyethylene material.

31. The liquid container material of claim 22, wherein the layer of foam material comprises a polystyrene material.

32. The liquid container material of claim 22, further comprising a liquid primer applied to the first side of the layer of container stock material.

33. A liquid container material, comprising:

a layer of container stock material comprising a first side and a second side;

a first layer of thermoplastic material applied to the first side of the layer of container stock material, wherein the first layer of thermoplastic material is compressed substantially through a portion of the layer of container stock material;

a second layer of thermoplastic material applied to the second side of the layer of container stock material; and

a layer of foam material applied to the first side of the layer of container stock material, wherein the at least one foam layer is applied with a third layer of thermoplastic material.

34. A liquid container material, comprising:

a layer of container stock material comprising a first side and a second side;

a liquid primer applied to the first side of the layer of container stock material, wherein the liquid primer is compressed substantially through a portion of the layer of container stock material; and

a layer of foam material applied to the first side of the layer of container stock material, wherein the at least one foam layer is applied with a layer of thermoplastic material.