权利要求：
1. A method of producing a sheet for use in forming an insulative cup, the method comprising the steps of
providing a strip of insulative cellular non-aromatic polymeric material,
providing a film having a first side arranged to face away from the strip and an opposite second side arranged to face toward the strip,
printing an ink layer on one of the first and second sides of the film to provide a printed film, and
laminating the printed film to the strip to form a sheet.
2. The method of claim 1, wherein the ink layer is printed on the second side of the film during the printing step.
3. The method of claim 1, wherein the ink layer is printed on the first side of the film during the printing step.
4. The method of claim 3, wherein the laminating step further comprises the steps of applying an adhesive to the printed film to form a skin and locating the adhesive between the ink layer and the strip of insulative cellular non-aromatic polymeric material.
5. The method of claim 1, wherein the printing step comprises the step of using a flexographic process to print the ink layer.
6. The method of claim 5, wherein the flexographically printing step comprises printing one or more colors of ink.
7. The method of claim 6, further comprising the step of selecting an ultraviolet curing ink and using the ultraviolet curing ink during the printing step.
8. The method of claim 6, further comprising the step of selecting an electron-beam curing ink and using the electron-beam curing ink during the printing step.
9. The method of claim 1, wherein the printing step comprises the step of using a rotogravure process to print the ink layer.
10. The method of claim 1, further comprising the steps of
cutting the sheet to form a body blank having a printed side and an opposite unprinted side and a floor blank having a printed side and an opposite unprinted side,
compressing portions of the body blank to cause the body blank to include a first portion having a first density and a second portion having a relatively greater second density,
forming a base from the body blank by coupling a portion of the printed side of the body blank to a portion of the unprinted side of the body blank, the base including a first end and an opposite second end,
forming a floor from the floor blank, and
joining the floor to the second end of the base to establish a body included in the container and formed to include an interior region defined by the floor and the base and to orient the floor relative to the body to cause the unprinted side of the floor blank to face toward the interior region and the printed side of the floor blank to face away from the interior region to establish the insulative cup.
11. The method of claim 10, wherein the first density is about 0.175 g/cm3 and the second density is about 0.350 g/cm3.
12. The method of claim 10, wherein the second portion of the body blank is the portion of the printed side of the body blank that is coupled to the portion of the unprinted side of the body blank.
13. The method of claim 1, further comprising the step of converting the sheet to form an insulative container formed to include an interior region.
14. The method of claim 13, wherein the laminating step further comprises the steps of applying an adhesive to the printed film to form a skin and locating the adhesive between the ink layer and the strip of insulative cellular non-aromatic polymeric material and wherein the strip of insulative cellular non-aromatic polymeric material is located between the adhesive and the interior region of the insulative container.
15. The method of claim 14, wherein the film is biaxially oriented polypropylene.
16. The method of claim 12, wherein the insulative cellular non-aromatic polymeric material is located between the ink layer and the interior region of the insulative cup and the insulative cellular non-aromatic polymeric material comprises a polypropylene base resin having a high melt strength, a polypropylene copolymer resin, at least one nucleation agent, and gas means for expanding the resins to reduce density.
17. The method of claim 16, wherein the gas means comprises carbon dioxide.
18. The method of claim 16, wherein the polypropylene base resin comprises broadly distributed molecular weight polypropylene characterized by a distribution that is unimodal.
19. The method of claim 16, wherein the polypropylene base resin further includes a polypropylene homopolymer resin.
20. The method of claim 12, wherein the insulative cellular non-aromatic polymeric material is located between the ink layer and the interior region of the insulative cup and the insulative cellular non-aromatic polymeric material comprises a broadly distributed molecular weight polypropylene characterized by a distribution that is unimodal.
21. The method of claim 12, wherein the insulative cellular non-aromatic polymeric material is located between the ink layer and the interior region of the insulative cup and is formed to include cells filled with gas and each cell is bounded by a cell wall provided in the insulative cellular non-aromatic polymeric material and configured to be inelastically deformable during exposure to localized plastic deformation.
22. The method of claim 12, wherein the insulative cellular non-aromatic polymeric material is located between the ink layer and the interior region of the insulative cup and the insulative cellular non-aromatic polymeric material comprises a high melt strength polypropylene characterized by long-chain branching to provide a predetermined balance of processability and high melt elasticity.
23. The method of claim 1, wherein the insulative cellular non-aromatic polymeric material comprises a polypropylene base resin having a high melt strength, a polypropylene copolymer resin, at least one nucleation agent, and gas means for expanding the resins to reduce density.
24. The method of claim 23, wherein the gas means comprises carbon dioxide.
25. The method of claim 23, wherein the polypropylene base resin comprises broadly distributed molecular weight polypropylene characterized by a distribution that is unimodal.
26. The method of claim 23, wherein the film is biaxially oriented polypropylene.
27. The method of claim 23, wherein the polypropylene base resin further includes a polypropylene homopolymer resin.
28. The method of claim 1, wherein the insulative cellular non-aromatic polymeric materials comprises a polypropylene base resin having a high melt strength, a polypropylene homopolymer resin, at least one nucleation agent, and gas means for expanding the resins to reduce density.
29. The method of claim 28, wherein the gas means comprises carbon dioxide.
30. The method of claim 28, wherein the polypropylene base resin comprises a broadly distributed molecular weight polypropylene characterized by a distribution that is unimodal.
31. The method of claim 1, wherein the insulative cellular non-aromatic polymeric material comprises a broadly distributed molecular weight polypropylene characterized by a distribution that is unimodal.
32. The method of claim 1, wherein a portion of the strip has a first density of about 0.175 g/cm3 and another portion of the strip has a second density about of about 0.350 g/cm3.
33. The method of claim 1, wherein the insulative cellular non-aromatic polymeric material is formed to include cells filled with gas and each cell is bounded by a cell wall provided in the insulative cellular non-aromatic polymeric material and configured to be inelastically deformable during exposure to localized plastic deformation.
34. The method of claim 1, wherein the insulative cellular non-aromatic polymeric material comprises a high melt strength polypropylene characterized by long-chain branching to provide a predetermined balance of processability and high melt elasticity.
35. A method of producing an insulative cup, the method comprising the steps of
providing a strip having a first side and an opposite second side,
printing graphics on a film to provide a first printed film,
laminating the first printed film to the strip to form a laminated sheet,
cutting the laminated sheet to form a body blank and a floor blank,
compressing portions of the body blank to cause the body blank to include a first portion having a first density and a second portion having a relatively greater second density,
forming a base from the body blank, the base including an inner wall and an opposite outer wall, and the base including a first end and an opposite second end,
forming a floor from the floor blank, and
joining the floor to the second end of the base to establish a body included in the container and formed to include an interior region defined by the floor and the base.
36. The insulative cup of claim 35, wherein the first printed film is adhered to the outer wall of the base to locate the base between the first printed film and the interior region.
37. The insulative cup of claim 35, further comprising printing graphics on the film to form a second printed film and adhering the second printed film to the inner wall of the base to locate the second printed film between the interior region and the base.
38. The insulative cup of claim 35, wherein the first printed film is adhered to the inner wall of the base to located the first printed film between the interior region and the base.
39. An insulative cup comprising
a container formed to include an interior region bounded by a side wall and a floor, wherein the side wall includes an inner surface and an outer surface and the container comprises an insulative cellular non-aromatic polymeric material,
a film having an inner surface coupled to the side wall of the container, wherein the outer surface of the side wall comprises a plurality of cells having an average width in a first direction in a range of less than about 1.0 millimeter, an average height in the first direction in a range of less than about 0.30 millimeters, and
an ink layer comprising relatively high resolution graphics printed on the inner surface of the film.
40. The insulative cup of claim 39, wherein the inner surface of the film is coupled to and substantially surrounding the outer surface of the side wall.
41. The insulative cup of claim 39, wherein the inner surface of the film is coupled to and substantially surrounding the inner surface of the side wall.
42. The insulative vessel of claim 39, wherein the plurality of cells further comprise an average width in a second direction of about 0.50 millimeters and an average height in the second direction in a range of less than about 0.30 millimeters.
43. The insulative vessel of claim 42, wherein the first direction comprises a machine direction and the second direction comprises a cross direction.
44. The insulative vessel of claim 39, wherein the resolution comprises at least about 150 lines per inch.
45. The insulative vessel of claim 43, wherein the ink layer is printed using a flexographic process.
46. The insulative vessel of claim 45, wherein the flexographic process comprises a central impression process.
47. The insulative vessel of claim 45, wherein the central impression process comprises an inline process.
48. The insulative vessel of claim 39, wherein the ink layer comprises one or more colors of an ultraviolet curing ink.
49. The insulative vessel of claim 39, wherein the ink layer comprises one or more colors of an electron-beam curing ink.
50. The insulative vessel of claim 42, wherein the ink layer comprises one or more colors of a combination of an ultraviolet curing ink and an electron-beam curing ink.
51. The insulative vessel of claim 44, wherein the ink layer is printed using a rotogravure process.
52. The insulative vessel of claim 39, wherein the plurality of cells further comprise an average aspect ratio of between about 1.0 and about 3.0.
53. The insulative vessel of claim 39, wherein the plurality of cells further comprise an average aspect ratio of between about 1.0 and about 2.0.
54. An insulative cup comprising
a container formed to include an interior region bounded by a side wall and a floor, wherein the side wall includes an inner surface and an outer surface and comprises an insulative cellular non-aromatic polymeric material,
a film having an inner surface coupled to and substantially surrounding the outer surface of the side wall of the container, and
an ink layer comprising relatively high resolution graphics printed on the inner surface of the film.
55. The insulative vessel of claim 54, wherein the film and the ink layer cooperate to provide a skin that is laminated to the outer surface of the side wall.
56. The insulative vessel of claim 54, wherein the insulative cellular non-aromatic polymeric material comprises polypropylene.
57. The insulative vessel of claim 56, wherein the film is made from polypropylene.
58. The insulative vessel of claim 57, wherein the film is made from biaxially oriented polypropylene.
59. The insulative vessel of claim 54, wherein the ink layer is printed using a flexographic process.
60. The insulative vessel of claim 59, wherein the flexographic process comprises a central impression process.
61. The insulative vessel of claim 59, wherein the central impression process comprises an inline process.
62. The insulative vessel of claim 54, wherein the ink layer is printed using a rotogravure process.
63. The insulative vessel of claim 54, wherein the ink layer comprises one or more colors of an ultraviolet curing ink.
64. The insulative vessel of claim 55, wherein the ink layer comprises one or more colors of an electron-beam curing ink.
65. The insulative vessel of claim 54, wherein the ink layer comprises one or more colors of a combination of an ultraviolet curing ink and an electron-beam curing ink.
具体实施方式：
[0033]A cup-manufacturing process 40 comprising a process for forming an insulative cup 10 having artwork on a skin 81 laminated onto a substrate 82 in accordance with the present disclosure is shown, for example, in FIGS. 1-6. An insulative cup 10 in accordance with the present disclosure is shown, for example, in FIGS. 11-18. Insulative cup 10 is made from a multi-layer sheet 80 formed during cup-manufacturing process 40 as suggested in FIGS. 11-18. As an example, multi-layer sheet 80 includes a skin 81 and a strip 82 of insulative cellular non-aromatic polymeric material as shown in FIG. 9. Another embodiment of a multi layer sheet 180 in accordance with the present disclosure is shown in FIG. 10. Two embodiments of a strip-formation stage are shown, for example, in FIGS. 7 and 8.
[0034]Cup-manufacturing process 40 includes a strip-forming stage 41, a film-layer forming stage 42, a film-layer printing stage 43, a laminating stage 44, and a cup-forming stage 45 as shown, for example, in FIG. 1. Strip-forming stage 41 forms and provides a strip 82 of insulative cellular non-aromatic polymeric material as suggested in FIGS. 7 and 8. Film-layer forming stage 42 forms and provides a film layer 54. Film-layer printing stage 43 prints graphics and text 66 on film layer 54 to provide a printed film 70 as shown in FIG. 1. Laminating stage 44 laminates printed film 70 to strip 82 of insulative cellular non-aromatic polymeric material to form a multi-layer sheet 80. Cup-forming stage 45, also called a converting step, forms insulative cup 10 from sheet 80 as shown for example in FIGS. 2-6.
[0035]Insulative cup 10 includes, for example, a body 11 having a sleeve-shaped side wall 18 and a floor 20 as shown in FIGS. 11-18. Floor 20 is coupled to body 11 and cooperates with side wall 18 to form an interior region 14 therebetween for storing food, liquid, or any suitable product. Body 11 also includes a rolled brim 16 coupled to an upper end of side wall 18 and a floor mount 17 coupled to a lower end of side wall 18 and to floor 20 as shown in FIG. 14.
[0036]Insulative cellular non-aromatic polymeric material is configured in accordance with the present disclosure to provide means for enabling localized plastic deformation in at least one selected region of body 11 (e.g., side wall 18, rolled brim 16, floor mount 17, and a floor-retaining flange 26 included in floor mount 17) to provide (1) a plastically deformed first material segment having a first density in a first portion of the selected region of body 11 and (2) a second material segment having a relatively lower second density in an adjacent second portion of the selected region of body 11 as suggested, for example, in FIGS. 11 and 15-18. In illustrative embodiments, the first material segment is thinner than the second material segment.
[0037]Insulative cup 10 is made of a multi-layer sheet 80 as suggested in FIG. 1. Sheet 80 comprises a strip 82 of insulative cellular non-aromatic polymeric material laminated with a skin having film layer 54 and ink layer 66 printed on film layer 54 to provide a cup having high-quality graphics as suggested, for example, in FIG. 1.
[0038]Film layer 54 is formed and provided by film-layer forming stage 42 as shown in FIG. 1. Film layer 54 is then printed with an ink layer 66 during film-layer printing stage 43. As an example, ink layer 66 includes graphics and the graphics are shown on insulative cup 10 as a pair of triangles in FIG. 13. However, graphics may be another other suitable graphic such as, but not limited to, symbols, text, photographs, images, combinations thereof, and the like, and may be in black and white or in color.
[0039]Film-layer printing stage 43 uses a printer 64 to print ink layer 66 on film layer 54 to provide printed film 70 as shown in FIG. 1. Printing may be done using conventional flexography, which is a form of printing that uses flexible rubber relief plates and highly volatile, fast-drying inks to print on a variety of substrates, including films of the type used as film layer 54. In particular, printing may be done using an in-line, central impression flexographic printing station. Alternatively, printing processes such as rotogravure may be used.
[0040]Central impression presses use a large-diameter common impression cylinder to carry the web around to each color station. The advantage of such a press is the ease of maintaining proper registration. The use of larger impression cylinders (i.e., up to 83 inches in diameter) has, in the past, led to an increase in press speed, but as drying methods have improved there is no longer a strict correlation between larger impression cylinders and increased speed. In-line presses are a type of multi-color press in which separate color stations are mounted in a horizontal line from front to back. They can handle a wider variety of web widths than can stack presses, and can also make use of turning bars to flip the web over, allowing easy reverse printing.
[0041]Two examples of the type of in-line, central impression flexographic printing stations which may be used in film-layer printing stage 43 are the XD and XG series of presses available from the Flexotecnica division of North American Cerutti Corporation in Milwaukee, Wis. Standard press widths are available from 32-60 inches (800-1525 mm) wide. Standard repeats are available at 30 (760), 33 (840) and 43 (1100) inches (mm). Extra large or Mega model of presses are available up to 83 inches (2100 mm) wide with 75 inch (1900 mm) repeats. Line speeds are available up to 1600 fpm (500 mpm), and they may be equipped with in-line vision for registration. They may include up to ten color stations.
[0042]The highly volatile, fast-drying inks which may be used in the printing of graphics are radiation-curing inks that dry or set with the application of ultraviolet light. ultraviolet curing ink vehicles are typically composed of fluid oligomers (i.e., small polymers), monomers (i.e., light-weight molecules that bind together to form polymers), and initiators that, when exposed to ultraviolet radiation, release free radicals (i.e., extremely reactive atoms or molecules that can destabilize other atoms or molecules and start rapid chain reactions) that cause the polymerization of the vehicle, which hardens to a dry ink film containing the pigment.
[0043]The most common configuration of ultraviolet curing equipment is a mercury vapor lamp. Within a quartz glass tube containing charged mercury, energy is added, and the mercury is vaporized and ionized. As a result of the vaporization and ionization, the high-energy free-for-all of mercury atoms, ions, and free electrons results in excited states of many of the mercury atoms and ions. As they settle back down to their ground state, radiation is emitted. By controlling the pressure that exists in the lamp, the wavelength of the radiation that is emitted can be somewhat accurately controlled, the goal being to ensure that much of the radiation that is emitted falls in the ultraviolet portion of the spectrum, and at wavelengths that will be effective for ink curing. ultraviolet radiation with wavelengths of 365 to 366 nanometers provides the proper amount of penetration into the wet ink film to effect drying. Another variation of radiation-curing inks which may be used in the printing of graphics are electron-beam curing inks. The formulation of such inks is less expensive than ultraviolet curing inks, but the electronic-beam curing equipment is more expensive.
[0044]Printed film 70 is produced by film-layer printing stage 43 and provided to laminating stage 44 as shown, for example, in FIG. 1. During laminating stage 44, adhesive 654 is applied to printed film 70 to produce a skin 81 which is coupled to strip 82 to form sheet 80 as suggested in FIG. 1. As an example, sheet 80 is wound to form a roll 78 which is stored for use at a later time in cup-forming stage 45. However, sheet 80 may be fed directly without storage to cup-forming stage 45.
[0045]An insulative cellular non-aromatic polymeric material produced in accordance with the present disclosure can be formed to produce an insulative cup 10 as suggested in FIGS. 2-9. As an example, the insulative cellular non-aromatic polymeric material comprises a polypropylene base resin having a high melt strength, a polypropylene copolymer or homopolymer (or both), and cell-forming agents including at least one nucleating agent and a blowing agent such as carbon dioxide. As a further example, the insulative cellular non-aromatic polymeric material further comprises a slip agent. The polypropylene base resin has a broadly distributed unimodal (not bimodal) molecular weight distribution.
[0046]Insulative cellular non-aromatic material is used during cup-manufacturing process 40 to make insulative cup 10 as suggested in FIGS. 1-6. Reference is hereby made to U.S. application Ser. No. 13/491,007 filed Jun. 7, 2012 and titled INSULATED CONTAINER for disclosure relating to an insulative container made from an insulative cellular non-aromatic polymeric material, which application is hereby incorporated in its entirety herein. Reference is hereby made to U.S. application Ser. No. 13/491,327 filed Jun. 7, 2012 and titled POLYMERIC MATERIAL FOR AN INSULATED CONTAINER for disclosure relating to such insulative cellular non-aromatic polymeric material, which application is hereby incorporated in its entirety herein.
[0047]Strip-forming stage 41 of cup-manufacturing process 40 provides strip 82 of insulative cellular non-aromatic polymeric material as shown in FIG. 1. In one illustrative example, strip-forming stage 41 uses a polypropylene-based formulation 121 in accordance with the present disclosure to produce strip 82 of insulative cellular non-aromatic polymeric material as shown in FIG. 7. Formulation 121 is heated and extruded in two stages to produce a tubular extrudate 124 that can be slit to provide strip 82 of insulative cellular non-aromatic polymeric material as illustrated, for example, in FIG. 7. A blowing agent in the form of a liquefied inert gas is introduced into a molten resin 122 in the first extrusion zone. As an example, strip-forming stage 41 uses a tandem-extrusion technique in which a first extruder 111 and a second extruder 112 cooperate to extrude strip 82 of insulative cellular non-aromatic polymeric material.
[0048]Strip-forming stage 41 of cup-manufacturing process 40 provides strip 82 of insulative cellular non-aromatic polymeric material as shown in FIG. 7. As shown in FIG. 7, a formulation 121 of insulative cellular non-aromatic polymeric material is loaded into a hopper 113 that is coupled to first extruder 111. Formulation 121 of insulative cellular non-aromatic polymeric material is moved from hopper 113 by a screw 114 included in first extruder 111. Formulation 121 is transformed into a molten resin 122 in a first extrusion zone of first extruder 111 by application of heat 105 and pressure from screw 114 as suggested in FIG. 7.
[0049]In exemplary embodiments, a physical blowing agent may be introduced and mixed into molten resin 122 after molten resin 122 is established. In exemplary embodiments, as discussed further herein, the physical blowing agent may be a gas introduced as a pressurized liquid via a port 115A and mixed with molten resin 122 to form a molten extrusion resin mixture 123, as shown in FIG. 7.
[0050]Extrusion resin mixture 123 is conveyed by screw 114 into a second extrusion zone included in second extruder 112 as shown in FIG. 7. There, extrusion resin mixture 123 is further processed by second extruder 112 before being expelled through an extrusion die 116 coupled to an end of second extruder 112 to form an extrudate 124. As extrusion resin mixture 123 passes through extrusion die 116, gas comes out of solution in extrusion resin mixture 123 and begins to form cells and expand so that extrudate 124 is established. As an example, strip-forming stage 41 uses a tandem-extrusion technique in which first and second extruders 111, 112 cooperate to extrude strip 82 of insulative cellular non-aromatic polymeric material.
[0051]As an exemplary embodiment shown in FIG. 7, the extrudate 124 may be formed by an annular extrusion die 116 to form a tubular extrudate 124. A slitter 117 then cuts extrudate 124 to establish strip 82 of insulative cellular non-aromatic polymeric material as shown in FIG. 7.
[0052]Extrudate means the material that exits an extrusion die. The extrudate material may be in a form such as, but not limited to, a sheet, strip, tube, thread, pellet, granule or other structure that is the result of extrusion of a polymer-based formulation as described herein through an extruder die. For the purposes of illustration only, a sheet will be referred to as a representative extrudate structure that may be formed, but is intended to include the structures discussed herein. The extrudate may be further formed into any of a variety of final products, such as, but not limited to, cups, containers, trays, wraps, wound rolls of strips of insulative cellular non-aromatic polymeric material, or the like.
[0053]As an example, strip 82 of insulative cellular non-aromatic polymeric material is wound to form a roll of insulative cellular non-aromatic polymeric material and stored for later use either in a cup-forming process. However, it is within the scope of the present disclosure for strip 82 of insulative cellular non-aromatic polymeric material to be used in-line with the cup-forming process.
[0054]As shown in FIG. 9, multi-layer sheet 80 is a composite formed of strip 82 of insulative cellular non-aromatic polymeric material onto which skin 81 is laminated from a roll 78 at a laminating stage 44. As an example, multi-layer sheet 80 is fed from roll 78 to the cup-forming stage 45 as suggested in FIG. 1 and shown in FIG. 2. Cup-forming stage 45 illustratively includes a body blank forming step 451, an optional body blank annealing step 451a, a cup-base forming step 452, and a brim-forming step 453 as shown in FIG. 12. Body blank forming step 451 uses laminated sheet 80 to make a body blank 92 as shown in FIG. 12. Cup-base forming step 452 uses body blanks 92 along with another laminated sheet 80 provided by another laminated roll 78 to form a floor blank 90, form side wall 18, and join side wall 18 to floor 20 to establish base 12 as suggested in FIG. 13. Brim-forming step 453 rolls top portion 22 of base 12 to form rolled brim 16 on base 12 as suggested in FIG. 14.
[0055]Body blank forming step 451 includes a laminated-roll loading step 4511, an optional annealing step 4511a, a compressing step 4512, a cutting step 4513, a collecting scrap step 4514, and an accumulating blanks step 4515 as shown in FIG. 13. Laminated-roll loading step 4511 loads laminated roll 76 onto a cutting machine such as a die cutting machine or metal-on-metal stamping machine. As a result, laminated sheet 80 is drawn into the cutting machine for processing in machine direction 67. The optional annealing step 4511a heats laminated sheet 80 as it moves to the cutting machine so that stresses in the non-aromatic polymer structure of laminated sheet 80 are released to reduce creasing and wrinkling in surfaces 106 and 108 of insulative cup 10.
[0056]An unexpected property of sheet 80 including strip 82 of insulative cellular non-aromatic polymeric material is its ability to form noticeably smooth, crease, and wrinkle free surfaces when bent to form a round article, such as insulative cup 10. Surface 106 is smooth and wrinkle free as is surface 108 as shown in FIG. 9. The smoothness of the surfaces 106 and 108 of the present disclosure is such that the depth of creases or wrinkles naturally occurring when subjected to extension and compression forces during cup-manufacturing process 40 is less than about 100 microns and even less than about 5 microns in most instances. At less than about 10 microns, the creases or wrinkles are not visible to the naked eye.
[0057]In addition to surface topography and morphology, another factor that was found to be beneficial to obtain a high quality insulative cup free of creases was the anisotropy of the insulative cellular non-aromatic polymeric strip. Aspect ratio is the ratio of the major axis to the minor axis of the cell. As confirmed by microscopy, in one exemplary embodiment the average cell dimensions in a machine direction 67 (machine or along the web direction) of an extruded strip 82 of insulative cellular non-aromatic polymeric material was about 0.0362 inches (0.92 mm) in width by about 0.0106 inches (0.27 mm) in height. As a result, a machine direction cell size aspect ratio is about 3.5. The average cell dimensions in a cross direction (cross-web or transverse direction) was about 0.0205 inches (0.52 mm) in width and about 0.0106 inches (0.27 mm) in height. As a result, a cross-direction aspect ratio is about 1.94. In one exemplary embodiment, it was found that for the strip to withstand compressive force during cup forming, one desirable average aspect ratio of the cells was between about 1.0 and about 3.0. In one exemplary embodiment one desirable average aspect ratio of the cells was between about 1.0 and about 2.0.
[0058]The ratio of machine direction to cross direction cell length is used as a measure of anisotropy of the extruded strip. In exemplary embodiments, a strip of insulative cellular non-aromatic polymeric material may be bi-axially oriented, with a coefficient of anisotropy ranging between about 1.5 and about 3. In one exemplary embodiment, the coefficient of anisotropy was about 1.8.
[0059]If the circumference of the cup is aligned with machine direction 67 of strip 82 with a cell aspect ratio exceeding about 3.0, deep creases with depth exceeding about 200 microns are typically formed on an inside surface of the cup making it unusable. Unexpectedly, it was found, in one exemplary embodiment, that if the circumference of the cup was aligned in the cross direction of extruded strip 82, which can be characterized by cell aspect ratio below about 2.0, no deep creases were formed inside of the cup, indicating that the cross direction of strip 82 was more resistant to compression forces during cup formation.
[0060]One possible reason for greater compressibility of an extruded strip with cells having aspect ratio below about 2.0 in the direction of cup circumference, such as in the cross direction, could be due to lower stress concentration for cells with a larger radius. Another possible reason may be that the higher aspect ratio of cells might mean a higher slenderness ratio of the cell wall, which is inversely proportional to buckling strength. Folding of the strip into wrinkles in the compression mode could be approximated as buckling of cell walls. For cell walls with longer length, the slenderness ratio (length to diameter) may be higher. Yet another possible factor in relieving compression stress might be a more favorable polymer chain packing in cell walls in the cross direction allowing polymer chain re-arrangements under compression force. Polymer chains are expected to be preferably oriented and more tightly packed in machine direction 67.
[0061]In exemplary embodiments, cell aspect ratio is about 2.0 when the formed cup circumference is aligned in the direction of extruded strip. As a result, the surface of extruded strip with crystal domain size below about 100 angstroms facing inside the cup may provide favorable results of achieving a desirable surface topography with imperfections less than about 5 microns deep.
[0062]In one aspect of the present disclosure, the polypropylene resin (either the base or the combined base and secondary resin) may have a density in a range of about 0.01 g/cm3 to about 0.19 g/cm3. In one exemplary embodiment, the density may be in a range of about 0.05 g/cm3 to about 0.19 g/cm3. In one exemplary embodiment, the density may be in a range of about 0.1 g/cm3 to about 0.185 g/cm3.
[0063]It has been found during development of the present disclosure that if the circumference of insulative cup 10 is aligned with the machine direction 67 of strip 82 of insulative cellular non-aromatic polymeric material, deep creases with a depth in excess of about 200 microns are typically formed on surface 108. Unexpectedly, it has been determined that if the circumference of insulative cup 10 is aligned generally perpendicular to machine direction 67, no deep creases are formed on surface 108, indicating that the cross-direction to machine direction 67 of extruded insulative cellular non-aromatic polymeric material is resistant to compression forces during formation of insulative cup 10. It is believed that this is a result of the orientation of the polymer chains of extruded insulative cellular non-aromatic polymeric material which are oriented and more tightly packed in machine direction 67.
[0064]As an example, equipment may be arranged such that rolled brim 16 of insulative cup 10 is arranged to be the cross direction during body blank forming step 451. After sheet 80 is provided, compressing step 4512 compresses portions of sheet 80 to form a compressed sheet. Cutting step 4513 cuts compressed sheet to cause body blank 92 to be cut from a blank-carrier sheet 94. Collecting scrap step 4514 collects blank-carrier sheet 94 after cutting step 4513 is complete so that blank-carrier sheet 94 may be recycled. Accumulating blanks step 4515 accumulates each body blank 92 to form a body blank stack 95 for use in cup-base forming step 452 as shown in FIG. 3. As another example, compressing step 4512 and cutting step 4513 may be combined such that they are performed generally at the same time by the same piece of equipment.
[0065]Cup-base forming step 452 includes a body blanks loading step 4521A, a heating body blank step 4522A, a wrapping body blank step 4523A, a forming body step 4524A, a laminated-roll loading step 4521B, a cutting floor blanks step 4522B, a shaping floor step 4523B, a heating floor step 4524B, a heating body step 4525A, a wrapping body step 4526, and a floor-seam forming step 4527 as shown in FIG. 4. Body blanks loading step 4521A loads body blank stack 95 into a cup-forming machine for further processing. Heating body blank step 4522A applies heat 96 to body blank 92. Wrapping body blank step 4523A wraps heated body blank 92 around a mandrel included in the cup-forming machine. Forming body step 4524A forms body 11 by compressing portions of side wall 18 using primary and auxiliary seam clamps included in the cup-forming machine. Primary and auxiliary seam clamps provide localize compression which results a portion of side wall 18 having thickness T2 and another portion having thickness T1 as shown in FIG. 14. As an example, thickness T2 is about equal to thickness T1.
[0066]Laminated-roll loading step 4521B loads another laminated roll 76 onto the cup-forming machine to cause laminated sheet 80 to be drawn into cup-forming machine for processing. Cutting floor blanks step 4522B cuts laminated sheet 80 to cause floor blank 90 to be cut from a blank-carrier sheet 94. Blank-carrier sheet 94 may then be collected and recycled. Shaping floor step 4523B forms floor 20 by inserting floor blank 90 into the mandrel of the cup-forming machine. Heating floor step 4524B applies heat 96 to floor 20 at the same time heating body step 4525A applies heat 96 to side wall 18. Wrapping body 4526 wraps support structure 19 around platform-support member 23 of floor 20. Floor-seam forming step 4527 compresses floor 20 and side wall 18 to establish a floor seam or seal between floor 20 and side wall 18 to establish base 12 which is then ready for brim-forming step 453 as shown in FIG. 4.
[0067]Cup-base forming step 452 maintains the thickness T1 of the side wall 18 as compared to a thermoforming process. Rather than heating an insulative cellular non-aromatic polymeric material and working it over a mandrel in the thermoforming process, subjecting portions of the wall of the resulting cup to thinning and potentially reducing the insulative and structural properties thereof, cup-base forming step 452 is an assembly process that does not require most of the entire side wall 18 to be subjected to melting temperatures. This provides the advantage of maintaining consistency in thickness T1 of side wall 18 and, thereby, consistent and maximized insulating properties as compared to vessels subjected to a deep draw thermoforming process.
[0068]Brim-forming step 453 includes a transferring cup-base step 4531, an optional lubricating top-portion step 4532, heating top-portion step 4533, and rolling top-portion step 4534 as shown in FIG. 5. Transferring cup-base step 4531 transfers base 12 from a cup-base forming machine to a brim-forming machine. Lubricating top-portion step 4532 lubricates top portion 22 of base 12. Heating top-portion step 4533 applies heat 96 to top portion 22 of base 12. Curling top-portion step 4534 curls top portion 22 away from interior region 14 to establish rolled brim 16 and form insulative cup 10.
[0069]Cup-packaging stage 46 includes a leak inspecting step 461, an accumulating cups step 462, and a packaging cups step 463 as shown in FIG. 6. Leak inspecting step 461 inspects each insulative cup 10 formed during brim-forming step 453 for leaks. Those cups failing the leak inspection are collected and recycled owing to formation of those cups from insulative cellular non-aromatic polymeric material. Those cups passing the leak inspection are accumulated in accumulating cups step 462 to form a stack 98 of insulative cups. Packaging cups step 463 stores stack 98 of insulative cups for storage, use, or transportation as shown in FIG. 6.
[0070]Another embodiment of a strip-forming stage 300 is shown for example in FIG. 8. Strip-forming stage 300 incorporates a blender 302 for material blending of the resin. Resin is fed into a primary extruder 304. In this example, a first physical blowing agent A 306 and a second physical blowing agent B 308 are introduced to expand the resin to reduce density. As an example, first physical blowing agent A 306 may be CO2, N2, or any other suitable alternative. Second physical blowing agent B 308 may be, for example, R134a as an example. The material exits the primary extruder 304 and is introduced into the secondary extruder 310. The two extruders 304 and 310 act as tandem extruders to promote material dispersion and homogeneity.
[0071]An annular die 312 is used to form a tube of material. A cooling can nose 314 uses air to promote formation of bubbles. The surface temperature of the cooling can nose is regulated. In one exemplary embodiment, opposing knives 316 are positioned preferably opposite each other (for example, at 3 and 9 o'clock) to slit the extrudate into two strips. Alternatively, a single knife can be used. Alternatively, the extrudate need not be slit at all. The extrudate thus formed can be inspected, for example by a laser thickness sensor 318 to ensure proper and uniform thickness.
[0072]A gas, such as, but not limited to, carbon dioxide, nitrogen, other relatively inert gas, a mixture of gases or the like, is introduced into the molten resin mixture to expand the polypropylene and reduce density by forming cells in the molten polypropylene. R134a or other haloalkane refrigerant may be used with the gas. In one aspect of the present disclosure, the cells formed in the insulative cellular non-aromatic polymeric material may have an average size in a range of about 0.010 to about 0.030 inches.
[0073]Other adjustments may be made to ensure a sufficiently small cell size and, thereby, facilitate a smoother surface. In illustrative embodiments, relatively greater amounts of carbon dioxide, nitrogen, other relatively inert gas, a mixture of gases or the like, may be introduced into the molten resin mixture to expand the polypropylene and further reduce its density by forming smaller cells in the molten polypropylene. Moreover, relatively greater amounts of copolymer may be added to the resin mix. Furthermore, adjustments may be made to the temperature of the cooling can during the extrusion stage. Still further, the tandem extruder arrangement shown in FIG. 7 may be replaced with a co-extrusion foaming die, which can facilitate putting a cap on one side of the strip.
[0074]As discussed above, cup-manufacturing process 40 is used to form a sheet 80 for use in forming insulative cup 10. Sheet 80 includes a skin 81 laminated to strip 82 of insulative cellular non-aromatic polymeric material as shown in FIG. 9. Skin 81 includes a film or film layer 658, an ink layer 656, and an adhesive layer 654. As an example, ink layer 656 may be printed on film 658 prior to adhering the skin to strip 82 of insulative cellular non-aromatic polymeric material. In the illustrative embodiment of FIG. 9, film 658 comprises biaxially oriented polypropylene film.
[0075]Another embodiment of a sheet 180 in accordance with the present disclosure is shown in FIG. 10. Sheet 180 includes outer skin 81, strip 82 of insulative cellular non-aromatic polymeric material, and an inner skin 83 as shown in FIG. 10. Inner skin 83 is similar to outer skin 81 in that inner skin 83 also includes adhesive layer 654, ink layer 656, and film 658. As a result, skin 81, 83 is arranged on both sides of strip 82 of insulative cellular non-aromatic polymeric material. In other embodiments, ink layer(s) 656 may be omitted on one or both sides.
[0076]An insulative cup 10 is formed using strip 82 of insulative cellular non-aromatic polymeric material in cup-manufacturing process 40 as shown in FIGS. 1-6. Insulative cup 10 includes, for example, a body 11 having a sleeve-shaped side wall 18 and a floor 20 coupled to body 11 to cooperate with the side wall 18 to form an interior region 14 for storing food, liquid, or any suitable product as shown in FIG. 11. Body 11 also includes a rolled brim 16 coupled to an upper end of side wall 18 and a floor mount 17 coupled to a lower end of side wall 18 and to the floor 20 as illustrated in FIGS. 11 and 13.
[0077]Body 11 is formed from a strip 82 of insulative cellular non-aromatic polymeric material as disclosed herein. In accordance with the present disclosure, strip 82 of insulative cellular non-aromatic polymeric material is configured through application of pressure and heat (though in exemplary embodiments configuration may be without application of heat) to provide means for enabling localized plastic deformation in at least one selected region of body 11 to provide a plastically deformed first sheet segment having a first density located in a first portion of the selected region of body 11 and a second sheet segment having a second density lower than the first density located in an adjacent second portion of the selected region of body 11 without fracturing the sheet of insulative cellular non-aromatic polymeric material so that a predetermined insulative characteristic is maintained in body 11.
[0078]A first 101 of the selected regions of body 11 in which localized plastic deformation is enabled by the insulative cellular non-aromatic polymeric material is in sleeve-shaped side wall 18 as suggested in FIGS. 11 and 15. Sleeve-shaped side wall 18 includes an upright inner tab514, an upright outer tab 512, and an upright fence 513 as suggested in FIGS. 11 and 14-17. Upright inner tab 514 is arranged to extend upwardly from floor 20 and configured to provide the first sheet segment having the first density in the first 101 of the selected regions of body 11. Upright outer tab 512 is arranged to extend upwardly from floor 20 and to mate with upright inner tab 514 along an interface I therebetween as suggested in FIG. 16. Upright fence 513 is arranged to interconnect upright inner and outer tabs 514, 512 and surround interior region 14. Upright fence 513 is configured to provide the second sheet segment having the second density in the first 101 of the selected regions of body 11 and cooperate with upright inner and outer tabs 514, 513 to form sleeve-shaped side wall 18 as suggested in FIGS. 14-17.
[0079]A second 102 of the selected regions of body 11 in which localized plastic deformation is enabled by the sheet of insulative cellular non-aromatic polymeric material is in rolled brim 16 included in body 11 as suggested in FIGS. 11 and 16. Rolled brim 16 is coupled to an upper end of sleeve-shaped side wall 18 to lie in spaced-apart relation to floor 20 and to frame an opening into interior region 14. Rolled brim 16 includes an inner rolled tab 164, an outer rolled tab