Stock material or miscellaneous articles – Hollow or container type article – Paper containing
Reexamination Certificate
2000-10-25
2004-02-17
Rice, Kenneth R. (Department: 3627)
Stock material or miscellaneous articles
Hollow or container type article
Paper containing
C428S526000, C428S530000, C428S533000, C427S372200, C427S388300, C427S385500, C427S458000, C427S421100, C427S430100
Reexamination Certificate
active
06692800
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a method for reducing the migration of aldehyde compounds found in packaging materials to the contents of packages made from such packaging materials. The present invention also relates to a package made from packaging material containing aldehyde compounds, wherein the migration of the aldehyde compounds found in the packaging material to the interior of the package is reduced. The invention still further relates to an improved paperboard packaging material prepared from recycled paper stock, wherein the recycled paper stock contains aldehyde compounds and amines to react with said aldehyde compounds, thereby preventing or slowing the migration of the aldehyde compounds from the paperboard packaging material when formed into a package.
BACKGROUND OF INVENTION
In recent years, the use of recycled materials to prepare packages has become much more prevalent than in the past. This increased recycling activity has been driven primarily by two factors: cost/economics and environmental concerns. The types of materials that are recycled include plastics, steel, and papers.
The use of recycled materials in preparing packages does cause several problems, however. One such problem is that recycled materials often contain impurities that are not found in virgin raw materials. For example, paperboard made from recycled paper stock typically contains aldehyde compounds. These aldehyde compounds are present in the recycled paper stock due to inks that are present in the original paper being recycled, and are not present in paper made from virgin stock.
These impurities in the recycled materials can, in certain instances, cause problems in the final package prepared from the recycled materials. For example, it has been found that when packages that contain food products are prepared using recycled paper stock that contains aldehyde compounds, the aldehydes can migrate from the recycled paper stock and into the package interior, where the product is stored. This migration, or transport, of the aldehyde compounds is undesirable because the aldehyde compounds impart off flavors and off odors to the food product when they come in contact with the food product.
The present invention provides a method for reducing this migration of such aldehyde compounds to the interior of the formed package. In the provided method, amine compounds are applied to the surface of the packaging material that forms the interior of the formed package. The amine compounds chemically react with aldehyde compounds that migrate through the packaging material, thereby forming a relatively chemically inert and less volatile compound. This chemical reaction slows or prevents the further migration of the aldehyde compounds to the interior of the package formed from the packaging material. The present invention further provides a package prepared from packaging materials containing aldehyde compounds, wherein the migration of the aldehyde compounds to the interior of the formed package is reduced or prevented.
BACKGROUND ART
The background art teaches urea-containing compositions. U.S. Pat. No. 3,293,057, issued Dec. 20, 1966, to Rumberger, claims a composition prepared by mixing together and reacting at an elevated temperature an aqueous dispersion of individual ingredients comprising starch, urea, and a polyfunctional aldehyde, wherein said starch is present in an amount of about 9% to about 95% by weight, said urea is present in an amount of about 5% to about 80% by weight, and said aldehyde is present in an amount of about 0.5% to about 20% by weight, all based on the total solids weight of said compositions, the pH of said dispersion being no greater than about 7.
The art also teaches compositions containing urea-aldehyde reaction products. U.S. Pat. No. 4,623,412, issued Nov. 18, 1986, to Bohme et al., claims a process for producing a resin impregnated linerboard for use in the production of corrugated board, wherein the surfaces of said resin impregnated linerboard have substantially no resinous material thereon. The claimed process comprises, in sequence: (i) providing an aqueous impregnating composition comprising (a) urea-aldehyde resin, (b) a catalyst, (c) a wetting agent, and (d) from 0to about 20% of a solvent, thereby providing a linerboard substrate; (ii) applying said aqueous impregnating composition to at least one surface of said linerboard substrate to form a coating thereon; (iii) applying an aqueous primer onto said coating of said impregnating composition such that said aqueous primer causes said impregnating composition to permeate said linerboard substrate to provide said linerboard substrate with a substantially polymeric core and having substantially no resinous material on the surfaces thereof; (iv) drying said impregnated linerboard under conditions for fully curing said urea-aldehyde resin to provide said linerboard with a substantially solid resinous core and having surfaces substantially free of said urea-aldehyde resin; (v) remoistening said fully cured linerboard; and (vi) passing the remoistened linerboard to a corrugator for incorporation into the corrugated board.
U.S. Pat. No. 4,377,649, issued Mar. 22, 1983, to Sweeney et al., claims a composition for use in the manufacture of cellulosic fiber materials, which comprises (a) from 1 to 50 wt % of a wax, (b) from 1 to 30 wt % of a starch, (c) from 1 to 50 wt % of a formaldehyde based resin, and (d) a liquid carrier.
U.S. Pat. No. 3,352,705, issued Nov. 14, 1967, to Moes et al., claims a method of producing a water resistant amylaceous pigment coating on paper or paperboard which comprises applying to said paper or paperboard a pigmented aqueous solution of a starch derivative, obtained by hydrolyzing starch at a temperature of between 60 and 300° C. with an inorganic acid in the presence of urea in an amount of from 5 to 50% by weight, calculated on the basis of starch used, and less than 50% of water, calculated on the weight of the mixture, to such an extent that a 25% aqueous solution of the starch derivative has an apparent viscosity not lower than 10 centipoise at 25° C., and reacting said starch derivative with an aldehyde reagent capable of rendering the same insoluble, said aldehyde reagent being selected from the group consisting of said aldehydes, aldehyde donors and melamine-aldehyde precondensates, and the pH during the insolubilization reaction being from about 6 to about 9.
U.S. Pat. No. 4,775,706, issued Oct. 4, 1988, to lovine et al., claims a water-resistant, alkaline curing corrugated adhesive composition comprising: (i) from about 66-35%, based on total weight of the adhesive, solids basis, of a polymer present in latex form, prepared by polymerizing a halohydrin quaternary ammonium monomer and a vinyl polymerizable monomer; (ii) from about 10-50% based on total weight of the adhesive of a starch component comprising ungelatinized starch or a mixture of ungelatinized and gelatinized starch; (iii) from about 40-80%, based on total weight of the adhesive, of water; and (iv) sufficient alkali to provide the adhesive with a pH of about 7.5 to 13.
U.S. Pat. No. 4,855,354, issued Aug. 8, 1989, to Mohler et al., claims a curable composition of matter which consists of: (a) a starch-aldehyde resin mixture, said mixture being formed by mixing said starch and said aldehyde resin; (b) a curing agent capable of reducing the pH of the composition, wherein said curing agent is present in an amount sufficient to accelerate the cure of the composition; and (c) a solvent selected from the group consisting of water, methanol, ethanol, isopropyl alcohol and mixtures thereof; wherein the ratio of aldehyde resin to starch is from 7:5 to 5:1 by weight.
U.S. Pat. No. 3,511,744, issued May 12, 1970, to Garrett, claims a method of producing sag-resistant fiberboard comprising the steps of forming fiberboard having at least two primary surfaces, each of which being located on a side of the board opposite from the other, coating at least a portion of one of said surfaces with a sag-resistant means
Rice Kenneth R.
Ryndak & Suri
The Quaker Oats Company
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