Claims
- 1. A method of preparing a microwaveable, mineral-filled polypropylene food contact article comprising:
(a) preparing a melt-compounded composition comprising from about 40 to about 90 percent by weight of a polypropylene polymer, from about 10 to about 50 percent by weight of a primary mineral filler and an effective odor-reducing amount of a basic organic or inorganic compound, said melt-compounded composition exhibiting an odor index of less than 0.75; (b) extruding said melt-compounded composition into sheet form; and (c) forming said food contact article from said sheet, wherein said basic organic or inorganic compound is operative to reduce undesirable odors in said melt-compounded composition to the aforesaid odor index value of 0.75 or less.
- 2. The method according to claim 1, wherein said primary filler is selected from the group consisting of mica, clays, siliceous materials, ceramics, glass, sulfate minerals, and mixtures thereof.
- 3. The method according to claim 2, wherein said primary filler is talc.
- 4. The method according to claim 3, wherein said primary filler is kaolin.
- 5. The method according to claim 1, wherein said primary filler is selected from the group consisting of mica, talc, kaolin, bentonite, wollastonite, milled glass fiber, glass beads, hollow glass beads, silica whiskers, silicon carbide whiskers and mixtures thereof.
- 6. The method according to claim 5, wherein said primary filler is bentonite.
- 7. The method according to claim 5, wherein said primary filler is wollastonite.
- 8. The method according to claim 1, wherein said basic organic or inorganic compound comprises the reaction product of an alkali metal or alkaline earth element with carbonates, phosphates, carboxylic acids as well as alkali metal and alkaline earth element oxides, hydroxides, or silicates and basic metal oxides, including mixtures of silicon dioxide with one or more of the following oxides:
magnesium oxide, calcium oxide, barium oxide, and mixtures thereof.
- 9. The method according to claim 8, wherein the basic organic or inorganic compound is selected from the group consisting of calcium carbonate, sodium carbonate, potassium carbonate, barium carbonate, aluminum oxide, sodium silicate, sodium borosilicate, magnesium oxide, strontium oxide, barium oxide, zeolites, sodium citrate, potassium citrate, sodium citrate, calcium stearate, potassium stearate, sodium phosphate, potassium phosphate, magnesium phosphate, mixtures of silicon dioxide with one or more of the following oxides:
magnesium oxide, calcium oxide, barium oxide, and mixtures of one or more of the above.
- 10. The method according to claim 9, wherein the basic inorganic compound is selected from the group consisting of calcium carbonate, sodium carbonate, potassium carbonate, barium carbonate, aluminum oxide, sodium silicate, sodium borosilicate, magnesium oxide, strontium oxide, barium oxide, zeolites, sodium phosphate, potassium phosphate, magnesium phosphate, mixtures of silicon dioxide with one or more of the following oxides: magnesium oxide, calcium oxide, barium oxide, and mixtures of one or more of the basic inorganic compounds set forth above, wherein the amount of the basic inorganic compound is from about 2 to about 20 weight percent of said article.
- 11. The method according to claim 10, wherein said basic inorganic compound is calcium carbonate.
- 12. The method according to claim 11, wherein calcium carbonate is present in said article from about 5 to about 20 weight percent.
- 13. The method according to claim 9, wherein said basic organic compound is selected from the group consisting of sodium stearate, calcium stearate, potassium stearate, sodium citrate, potassium citrate, and mixtures of these wherein the amount of the basic organic compound is from about 0.5 to about 2.5 weight percent of said article.
- 14. The method according to claim 1, wherein said composition exhibits an odor index of less than about 0.6.
- 15. The method according to claim 1, wherein said article is a bowl or a plate.
- 16. The method according to claim 1, wherein said article is formed, or thermoformed by application of pressure, by application of vacuum, or by a combination of vacuum and pressure, into the shape of a container; said container exhibiting a melting point of no less than about 250° F., said container being dimensionally stable and resistant to grease, sugar and water at temperatures up to at least 220° F. and of sufficient toughness to be resistant to cutting by serrated polystyrene flatware.
- 17. The method according to claim 16, wherein said article has at least one micronodular food contact surface.
- 18. The method according to claim 17, wherein said micronodular surface is produced through vacuum thermoforming on the side opposite said micronodular food contact surface.
- 19. The method according to claim 18, wherein said micronodular food contact surface exhibits a surface gloss of less than about 35 at 75° as measured by TAPPI method T480-OM 92.
- 20. The method according to claim 20, wherein said micronodular food contact surface exhibits a Parker Roughness Value of at least about 12 microns.
- 21. The method according to claim 1, wherein said polypropylene polymer is selected from the group consisting of: isotactic polypropylene, co-polymers of propylene and ethylene wherein the ethylene moiety is less than about 10 percent of the units making up the polymer and mixtures thereof.
- 22. The method according to claim 21, wherein said polymer is isotactic polypropylene and has a melt-flow index from about 0.3 to about 4.
- 23. The method according to claim 22, wherein said polypropylene has a melt flow index of about 1.5.
- 24. The method according to claim 1, wherein said composition further includes a polyethylene component.
- 25. The method according to claim 24, wherein said polyethylene is selected from the group consisting of HDPE, LDPE, LLDPE, MDPE and mixtures thereof.
- 26. The method according to claim 24, wherein said polyethylene component comprises HDPE.
- 27. The microwaveable article according to claim 24, wherein said polyethylene component comprises LLDPE.
- 28. The method according to claim 24, wherein said article ftirther includes titanium dioxide.
- 29. The microwaveable article according to claim 1, wherein said article exhibits a melting point of from about 250 to about 330° F.
- 30. The method according to claim 1, wherein said article is substantially free from volatile C8 and C9 organic ketones.
- 31. The method according to claim 1, wherein said article is prepared from a melt-compounded polypropylene mineral filled composition which is produced at a process melt temperature of less than about 425° F.
- 32. The method according to claim 31, wherein said article is produced from a melt-compounded polypropylene mineral filled composition which is prepared at a temperature below about 400° F.
- 33. The method according to claim 31, wherein said article is thermoformed from an extruded sheet produced from a melt-compounded polypropylene mineral filled composition which was prepared at a process melt temperature of less than about 425° F.
- 34. The method according to claim 1, wherein said melt processed polypropylene mineral filled composition is melt-compounded in a nitrogen atmosphere.
- 35. A microwaveable, mineral filled polypropylene food contact article formed from a sheet of a melt-compounded composition comprising from about 40 to about 90 percent by weight of a polypropylene polymer, from about 10 to about 50 percent by weight of a primary mineral filler and an effective odor-reducing amount of a basic organic or inorganic compound operative to impart an odor index of less that about 0.75 to said melt-compounded composition.
- 36. The microwaveable article according to claim 35, wherein the basic organic or inorganic compound is selected from the group consisting of calcium carbonate, sodium carbonate, potassium carbonate, barium carbonate, aluminum oxide, sodium silicate, sodium borosilicate, magnesium oxide, strontium oxide, barium oxide, zeolites, sodium citrate, potassium citrate, calcium stearate, potassium stearate, sodium phosphate, potassium phosphate, magnesium phosphate, mixtures of silicon dioxide with one or more of the following oxides: magnesium oxide, calcium oxide, barium oxide, and mixtures of one or more of the above.
- 37. The microwaveable article according to claim 36, wherein the basic inorganic compound is selected from the group consisting of calcium carbonate, sodium carbonate, potassium carbonate, barium carbonate, aluminum oxide, sodium silicate, sodium borosilicate, magnesium oxide, strontium oxide, barium oxide, zeolites, sodium phosphate, potassium phosphate, magnesium phosphate, mixtures of silicon dioxide with one or more of the following oxides: magnesium oxide, calcium oxide, barium oxide, and mixtures of one or more of the basic inorganic compounds set forth above, wherein the amount of the basic inorganic compound is from about 5 to about 20 weight percent of said article.
- 38. The microwaveable article according to claim 37, wherein said basic inorganic compound is calcium carbonate.
- 39. The microwaveable article according to claim 37, wherein calcium carbonate is present in said article from about 8 to about 12 weight percent.
- 40. The microwaveable article according to claim 35, wherein said basic organic compound is selected from the group consisting of sodium stearate, calcium stearate, potassium stearate, sodium citrate, potassium citrate, and mixtures of these wherein the amount of the basic organic compound is from about 0.5 to about 2.5 weight percent of said article.
- 41. The article of manufacture according to claim 35, in the form of a plate having a substantially planar center portion;
a first rim portion extending outwardly therefrom, said first rim portion being upwardly convex and subtending a first arc with a first radius of curvature; a second rim portion joined to said first rim portion, and extending outwardly therefrom, said second rim portion being downwardly convex, subtending a second arc with a second radius of curvature; a third rim portion joined to said second rim portion and extending outwardly therefrom, said third rim portion being downwardly convex, subtending a third arc with a third radius of curvature as well as a tangent thereto which is substantially parallel to the plane of said substantially planar center section; and, a fourth rim portion joined to said third rim portion and extending outwardly therefrom, said fourth rim portion being downwardly convex subtending a fourth arc having a fourth radius of curvature, wherein the length of said second arc of said second rim portion is substantially less than the length of said fourth arc of said fourth rim portion which, in turn, is substantially less than the length of said first arc of said first rim portion and wherein said fourth radius of curvature of said fourth rim portion is less than said third radius of curvature of said third rim portion which , in turn, is less than said second radius of curvature of said second rim portion and wherein the angle of said first arc is greater that about 55 degrees and the angle of said third arc is greater than about 45 degrees.
- 42. The plate according to claim 41, wherein the angle of said fourth arc is less than about 75 degrees.
- 43. The plate according to claim 41, wherein the length of said first arc is substantially equivalent to the length of said third arc and said first radius of curvature of said first arc is substantially equivalent to said third radius of curvature of said third arc.
- 44. The plate according to claim 41, wherein the height of the center of curvature of said first rim portion above the plane of said substantially planar portion is substantially less than the distance by which the center of curvature of said rim portion is below the plane of said substantially planar portion.
- 45. The plate according to claim 41, wherein the horizontal displacement of the center of curvature of said second rim portion from the center of curvature of said first rim portion is at least about twice said first radius of curvature of said first rim portion.
- 46. The plate according to claim 41, wherein said height of the center of curvature of said third rim portion above the plane of said substantially planar portion is less than the height of the center of curvature of said fourth rim portion above the plane of said substantially planar portion.
- 47. The plate according to claim 41, wherein the horizontal displacement of the center of curvature of said second rim portion is located outwardly from the center of curvature of both said third and fourth rim portions.
- 48. The plate according to claim 41, wherein the height of the center of curvature of said third rim portion above the plane of said substantially planar portion is less than about 0.75 times the radius of curvature of said fourth rim portion and the height of the center of curvature of said fourth rim portion above the plane of said substantially planar portion is at least about 0.4 times said first radius of curvature of said first rim portion.
- 49. A low temperature process for preparing a polypropylene mineral filled melt-compounded composition comprising a basic odor suppressing agent, from about 40 to about 90 percent by weight of a polypropylene polymer and from about 10 to about 50 percent by weight of a mineral filler said melt-compounded composition exhibiting an odor index of less than about 0.75 said process comprising the sequential steps of:
(a) preheating a polypropylene polymer while maintaining the polymer below a maximum temperature of about 350OF; followed by (b) admixing a mineral filler to said pre-heated polymer in an amount from 10 to about 50 percent by weight based on the combined weight of resin and filler; followed by (c) extruding said mixture.
- 50. The process according to claim 49, wherein said maximum temperature of Step (a) is about 260° F.
- 51. The process according to claim 49, wherein said polymer is melted through the application of shear.
- 52. The process according to claim 49, wherein said polypropylene polymer is preheated prior to said admixing step externally to the vessel in which said step of admixing the mica takes place.
- 53. The process according to claim 49, wherein the duration of Step (b) is a maximum of about 5 minutes.
- 54. The process according to claim 49, wherein the duration of Step (b) is a maximum of about 3 minutes.
- 55. The process according to claim 49, wherein said basic odor suppressing agent is added to the mixture simultaneously with said mineral filler in step (b) of the process.
- 56. The process according to claim 55, wherein said steps of preheating said polymer and admixing said mineral filler and odor suppressing compound to said resin are carried out in a batch mode in a mixing chamber provided with a pair of rotating rotors.
- 57. The process according to claim 49, wherein said odor suppressing compound is a basic organic or inorganic compound comprising the reaction product of an alkali metal or an alkaline earth element with carbonates, phosphates, carboxylic acids, as well as alkali metal and alkaline earth element oxides, hydroxides or silicates, basic metal oxides including mixtures of silicon dioxide with one or more of the following oxides: magnesium oxide, calcium oxide, barium oxide, and mixtures of one or more of the organic or inorganic compounds set forth above.
- 58. The process according to claim 57, wherein the basic organic or inorganic compound is selected from the group consisting of calcium carbonate, sodium carbonate, potassium carbonate, barium carbonate, aluminum oxide, sodium silicate, sodium borosilicate, magnesium oxide, strontium oxide, barium oxide, zeolites, sodium citrate, potassium citrate, sodium stearate, calcium stearate, potassium stearate, sodium phosphate, potassium phosphate, magnesium phosphate, mixtures of silicon dioxide with one or more of the following oxides: magnesium oxide, calcium oxide, barium oxide, and mixtures of one or more of the organic or inorganic compounds set forth above.
- 59. The process according to claim 58, wherein the basic inorganic compound is selected from a group consisting of calcium carbonate, sodium carbonate, potassium carbonate, barium carbonate, aluminum oxide, sodium silicate, sodium borosilicate, magnesium oxide, strontium oxide, barium oxide, zeolites, sodium phosphate, potassium phosphate, magnesium phosphate, mixtures of silicon dioxide with one or more of the following oxides: magnesium oxide, calcium oxide, barium oxide, and mixtures of one or more of the basic inorganic compounds set forth above and wherein the amount of the basic inorganic compound is from about 5 to about 20 weight percent of the composition.
- 60. A crack-resistant, food contact article having a wall thickness from about 10 to about about 80 mils consisting essentially of from about 40 to about 90 percent by weight of a polypropylene polymer, from about 10 to about 60 percent by weight of a mineral filler, from about 1 to about 15 percent by weight polyethylene, from about 0.1 to about 5 weight percent titanium dioxide and optionally including a basic organic or inorganic compound comprising the reaction product of an alkali metal or alkaline earth element with carbonates, phosphates, carboxylic acids as well as alkali metal and alkaline earth element oxides, hydroxides, or silicates and basic metal oxides, including mixtures of silicon dioxide with one or more of the following oxides: magnesium oxide, calcium oxide, barium oxide, and mixtures thereof.
- 61. The crack-resistant food contact article according to claim 60, wherein said basic organic or inorganic compound comprises calcium carbonate and said calcium carbonate is present in an amount of from about 5 to about 20 weight percent.
- 62. The crack-resistant, food contact article according to claim 60 wherein polyethylene is present from about 2.5 to about 15 percent by weight.
- 63. The crack-resistant, food contact article according to claim 62, wherein polyethylene is present from about 4 to about 5 weight percent.
- 64. The crack-resistant, food contact article according to claim 60, wherein titanium dioxide is present from about 0.1 to about 3 weight percent.
- 65. The crack-resistant, food contact article according to claim 64, wherein titanium dioxide is present from about 0.25 to about 2 percent by weight.
- 66. The crack-resistant, food contact article according to claim 60 wherein titanium dioxide is present in an amount of at least about 0.5 percent by weight.
- 67. The crack-resistant, food contact article according to claim 60, wherein said article has a wall caliper of from about 110 to about 50 mils.
- 68. The crack-resistant, food contact article according to claim 67, wherein said article has a wall caliper of from about 15 to about 25 mils.
- 69. The crack-resistant, food contact article according to claim 60, wherein said rineral filler is mica.
- 70. The crack-resistant, food contact article according to claim 60, wherein said polypropylene polymer is isotactic polypropylene.
- 71. The crack-resistant, food contact article according to claim 70, wherein said isotactic polypropylene has a melt index of from about 0.3 to about 4.
- 72. The crack-resistant, food contact article according to claim 71, wherein said isotactic polypropylene has a melt flow index of about 1.5.
- 73. The crack-resistant, food contact article according to claim 60, wherein said polyethylene is HDPE.
- 74. The crack-resistant, article according to claim 60, wherein said polyethylene is LLDPE.
- 75. A method of preparing a microwaveable, mineral-filled polpropylene food contact article comprising:
(a) preparing a melt-compounded composition comprising from about 40 to about 90 percent by weight of a polypropylene polymer and from about 10 to about 50 percent by weight of a mineral filler and optionally an effective amount of an odor-reducing compound; said melt-compounded composition exhibiting a relative aroma index, relative to a 30 weight percent mica composition of less than 0.75; (b) extruding said melt-compounded composition into sheet form; and (c) forming said food contact article from said sheet.
- 76. The method according to claim 75, wherein said mineral filler is selected from the group consisting of mica, clays, siliceous materials, ceramics, glass, ceramics, sulfate minerals, and mixtures thereof.
- 77. The method according to claim 76, wherein said mineral filler is selected from the group consisting of mica, talc, kaolin, bentonite, wollastonite, milled glass fiber, glass beads, hollow glass beads, silica whiskers, silicon carbide whiskers and mixtures thereof.
- 78. The method according to claim 77, wherein said mineral filler is talc.
- 79. The method according to claim 77, wherein said mineral filler is kaolin.
- 80. The method according to claim 77, wherein said mineral filler is bentonite.
- 81. The method according to claim 77, wherein said mineral filler is wollastonite.
- 82. The method according to claim 75, wherein said melt-compounded composition includes a basic odor suppressing compound.
- 83. The method according to claim 82, wherein said basic odor suppressing compound is a carbonate or hydroxide of an alkali metal or an alkaline earth element.
- 84. The method according to claim 83, wherein said basic odor suppressing compound is calcium carbonate.
- 85. The method according to claim 75, wherein said melt-compounded composition exhibits a relative aroma index, relative to a 30 weight percent mica, polypropylene composition of less than about 0.6.
- 86. A method of preparing a microwaveable, mineral-filled polypropylene food contact article comprising:
(a) preparing a melt-compounded composition comprising from about 40 to about 90 percent by weight of a polypropylene polymer, from about 10 to about 50 percent by weight of a primary mineral filler and optionally an effective odor-reducing amount of a basic or optionally acidic organic or inorganic compound,; (b) extruding said melt-compounded composition into sheet form; and (c) forming said food contact article from said sheet, wherein the melt-compounded composition exhibits a relative aroma Index value of 0.75 or less.
- 87. The method according to claim 86, wherein said primary mineral filler is talc.
- 88. The method according to claim 86, wherein said primary mineral filler is kaolin.
- 89. The method according to claim 86, wherein said primary mineral filler is bentonite.
- 90. The method according to claim 86, wheren said primary mineral filler is wollastonite.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/267,716, filed Mar. 12, 1999 entitled DISPOSABLE, MICROWAVEABLE CONTAINERS HAVING SUITABLE FOOD CONTACT COMPATIBLE OLFACTORY PROPERTIES AND PROCESS FOR THEIR MANUFACTURE which was a non-provisional patent application based on U.S. Provisional patent application Ser. No. 60/078,923, filed Mar. 20, 1998 also entitled DISPOSABLE, MICROWAVEABLE CONTAINERS HAVING SUITABLE FOOD CONTACT COMPATIBLE OLFACTORY PROPERTIES AND PROCESS FOR THEIR MANUFACTURE, the priority of which applications is hereby claimed.
Provisional Applications (1)
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Number |
Date |
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60078923 |
Mar 1998 |
US |
Divisions (1)
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Number |
Date |
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Parent |
09330266 |
Jun 1999 |
US |
Child |
09766694 |
Jan 2001 |
US |
Continuation in Parts (1)
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Number |
Date |
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09267716 |
Mar 1999 |
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Child |
09330266 |
Jun 1999 |
US |