Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material

Definitions

• the present invention is related to, and claims the benefit of 119(e) priority to U.S. provisional patent application Ser. No. 60/698,274; entitled “MULTDLAYERED PAPER OR PAPERBOARD SUBSTRATE HAVING IMPROVED SULFUR DIOXIDE HOLDOUT", which was filed on July 11, 2005, and is hereby incorporated, in its entirety, herein by reference.
• This application is also related to and claims the benefit of 119(e) priority to U.S. provisional patent application Ser. No.
• the invention relates to the papermaking art and, in particular, to the manufacture of paper or paperboard substrates, paper-containing articles such as multilayered paper or paperboard or corrugated-based packaging, having a functional layer, as well as methods of making and using the same.
• Paper substrates containing functional layers are highly desired by several niche markets. Each functional layer may be specifically tailored to each market demand and specifications depending on the packaging requirement for consumer goods. These packaging requirements are IPK-034214-US/WO - specifically determined by the risks associated with packaging and shipping such goods around the country and around the world.
• Such demands from such markets may require functionalities to be programmed within the functional layer of paper substrate that, when the paper substrate is incorporated into a package, the functionality itself prohibit and/or make it costly and/or less efficient to manufacture and/or convert the substrate so as to be incorporated into a paper-based package.
• there is an unmet need for all markets to be able to program tailored functionality into a coating layer of a paper substrate e.g. based upon the nature of the consumer goods to be packaged and/or shipped) so that, when the paper substrate is incorporated into a such packages, there is little or no loss of manufacturing/conversion efficiency and thus little or no increase in overhead costs for production of such packages.
• Figure 1 A first schematic cross section of just one exemplified embodiment of the paper substrate that is included in the paper substrate of the present invention.
• Figure 2 A second schematic cross section of just one exemplified embodiment of the paper substrate that is included in the paper substrate of the present invention.
• Figure 3 A third schematic cross section of just one exemplified embodiment of the paper substrate that is included in the paper substrate of the present invention.
• Figure 4 A exemplified embodiment of a package blank that contains the substrate of the present invention.
• Figure 5 A close-up view of a flap portion of the package blank shown in Figure 4 wherein a treated portion is shown as covering at least a part of the flap.
• Figure 6 A section view of an untreated portion of the flap portion in Figure 5 shown taken along section line 6-6 of Figure 5.
• Figure 7 A section view of a treated portion of the flap portion in Figure 5 shown taken along section line 7-7 of Figure 5.
• the inventors have surprisingly found a paper substrate containing a functional layer that, when incorporated into a package for shipping, is capable of minimizing the costly impact of that functionality on the downstream manufacturing/converting requirements by increasing manufacturing/converting efficiency that otherwise would render the use of such functionality cost prohibitive.
• the paper substrate contains a web of cellulose fibers.
• the source of the fibers maybe from any fibrous plant.
• at least a portion of the pulp fibers may be provided from non- woody herbaceous plants including, but not limited to, kenaf, hemp, jute, flax, sisal, or abaca although legal restrictions and other considerations may make the utilization of hemp and other fiber sources impractical or impossible.
• the paper substrate of the present invention may contain recycled fibers and/or virgin fibers. Recycled fibers differ from virgin fibers in that the fibers may have gone through the drying process at least once, preferably several times.
• the paper substrate of the present invention may contain from 1 to 99 wt%, preferably from 5 to 95 wt%, most preferably from 60 to 80 wt% of cellulose fibers based upon the total weight of the substrate, including 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 99 wt%, and including any and all ranges and subranges therein.
• the sources of the cellulose fibers are from softwood and/or hardwood.
• the paper substrate of the present invention may contain from 1 to 100 wt%, preferably from 5 to 95 wt%, cellulose fibers originating from softwood species based upon the total amount of cellulose fibers in the paper substrate. This range includes 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100wt%, including any and all ranges and subranges therein, based upon the total amount of cellulose fibers in the paper substrate.
• the paper substrate may alternatively or overlappingly contain from 0.01 to 100 wt% fibers from softwood species, preferably from 0.1 to 95wt%, most preferably from 1 to 90wt% based upon the total weight of the paper substrate.
• the paper substrate contains not more than 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100wt% fibers from softwood species based upon the total weight of the paper substrate, including any and all ranges and subranges therein.
• the paper substrate of the present invention may contain from 1 to 100 wt%, preferably from 5 to 95 wt%, cellulose fibers originating from hardwood species based upon the total amount of cellulose fibers in the paper substrate. This range includes 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100wt%, including any and all ranges and subranges therein, based upon the total amount of cellulose fibers in the paper substrate.
• the paper substrate may alternatively or overlappingly contain from 0.01 to 100 wt% fibers from hardwood species, preferably from 5 to 95 wt%, cellulose fibers originating from hardwood species based upon the total amount of cellulose fibers in the paper substrate.
• the paper substrate contains not more than 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99 and 100wt% fibers from hardwood species based upon the total weight of the paper substrate, including any and all ranges and subranges therein.
• the hardwood/softwood ratio be from 0.001 to 1000.
• This range may include 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 including any and all ranges and subranges therein and well as any ranges and subranges therein the inverse of such ratios.
• the softwood and/or hardwood fibers contained by the paper substrate of the present invention may be modified by physical and/or chemical means.
• physical means include, but is not limited to, electromagnetic and mechanical means.
• Means for electrical modification include, but are not limited to, means involving contacting the fibers with an electromagnetic energy source such as light and/or electrical current.
• Means for mechanical modification include, but are not limited to, means involving contacting an inanimate object with the fibers. Examples of such inanimate objects include those with sharp and/or dull edges.
• Such means also involve, for example, cutting, kneading, pounding, impaling, etc means.
• Examples of chemical means include, but is not limited to, conventional chemical fiber modification means including crosslinking and precipitation of complexes thereon.
• modification of fibers may be, but is not limited to, those found in the following patents 6,592,717, 6,592,712, 6,582,557, 6,579,415, 6,579,414, 6,506,282, 6,471,824, 6,361,651, 6,146,494, Hl,704, 5,731,080, 5,698,688, 5,698,074, 5,667,637, 5,662,773, 5,531,728, 5,443,899, 5,360,420, 5,266,250, 5,209,953, 5,160,789, 5,049,235, 4,986,882, 4,496,427, 4,431,481, 4,174,417, 4,166,894, 4,075,136, and 4,022,965, which are hereby incorporated, in their entirety, herein by reference.
• Sources of "Fines” may be found in SaveAll fibers, recirculated streams, reject streams, waste fiber streams.
• the amount of "fines" present in the paper substrate can be modified by tailoring the rate at which such streams are added to the paper making process.
• the paper substate preferably contains a combination of hardwood fibers, softwood fibers and "fines" fibers.
• "Fines" fibers are, as discussed above, recirculated and are typically not more that 100 ⁇ m in length on average, preferably not more than 90 ⁇ m, more preferably not more than 80 ⁇ m in length, and most preferably not more than 75 ⁇ m in length.
• the length of the fines are preferably not more than 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 ⁇ m in length, including any and all ranges and subranges therein.
• the paper substrate contains from 0.01 to 100 wt% fines, preferably from 0.01 to 50wt%, most preferably from 0.01 to 15wt% based upon the total weight of the substrate.
• the paper substrate contains not mort than 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100wt% fines based upon the total weight of the paper, including any and all ranges and subranges therein.
• the paper substrate may alternatively or overlappingly contain from 0.01 to 100 wt% fines, preferably from 0.01 to 50wt%, most preferably from 0.01 to 15wt% based upon the total weight of the fibers contained by the paper substrate.
• the paper substrate contains not more than 0.01, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100wt% fines based upon the total weight of the fibers contained by the paper substrate, including any and all ranges and subranges therein.
• the paper substrate may also contain a functional layer.
• the functional layer may contain additives that permit the layer to be a holdout layer.
• a holdout layer may be those that holdout or reduce the penetration of grease, water, water vapor, salt air, carbon dioxide, sulfur dioxide, hydrogen sulfide, or other solids/gases/liquids which pose a threat to surfaces of, for example, metallic objects, consumables such as fruits and vegetables, as well as other consumer/manufacturing goods.
• paper substrates containing holdout layers include United States Published Patent Applications 20020182381; 20040221976 and US provisional applications having USSNs 60/698,274 filed July 11, 2005 and 60/731,897, filed on October 31, 2005, which are hereby incorporated, in their entirety, herein by reference.
• the functional layer may contain the additives mentioned in these applications so as to impart such functionality in the layer, the substrate, and resulting package made therefrom.
• the functional layer may also contain releasable additives.
• a releasable additive may be vapor corrosion inhibitors . Examples of such inhibitors may be found in US patents 6,833,334; 6,617,415; 6,555,600; 6,444,595; 6,420,470; 6,331,044; 6,292,996; 6,156,929; 6,132,827; 6,054,512; 6,028,160; 5,937,618; 5,896,241; 5,889,639; 5,773,105; 5,736,231; 5,715,945; 5,712,008; 5,705,566; 5,486,308; 5,391,322; 5,324,448; 5,139,700; 5,209,869; 5,344,589; 4,313,836; 4,312,768; 4,151,099; 4,101,328; 6,429,240; 6,273,993; 6,255,375; and 4,685,563 and in US application having USSN 60/731,897, filed
• the functional layer may also contain an antifouling agent and/or antimicrobial agent and may serve to be antifouling and/or antimicrobial. Alternatively, it may serve to release such antifouling and/or antimicrobial agents into the local environment. Examples of such antimicrobial agents are those found in United States Published Patent Applications 20020182381 ; 20040221976, and United States applications having USSNs 60/585757; 11/175899; and 11/175700, which are hereby incorporated, in their entirety, herein by reference.
• the paper substrate of the present invention may contain a functional layer containing a film-forming compound.
• the film-forming compound may be any film-forming compound, examples of preferred film-forming compounds maybe those that have Tg, glass transition temperatures, of not greater than 35O 0 C.
• the Tg may be any Tg, but preferably not greater than 350, 340, 330, 325, 320, 310, 300, 290, 280, 275, 270, 260, 250, 225, 200, 175, 150, 125, and 100, including any and all ranges and subranges therein.
• An example of such a film forming compound is a styrene acrylate-containing compound such as Dow latex 229804 and/or starch such as Ethylex 2035 Starch.
• the film forming compound may be present in the functional layer from 0 to 100%, preferably from 50 to 150 ppm, based on the total weight of the functional layer, including 0, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, and 95 wt% based on the total weight of the functional layer, including any and all ranges and subranges therein.
• the film forming compound may be present in the functional layer at any amount, preferably 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, and 150 ppm based on the total weight of the functional layer, including any and all ranges and subranges therein.
• the functional layer may be present at any weight.
• the functional layer may be present at a weight that ranges from 1 to 25 gsm, preferably from 2 to 20 gsm, more preferably from 3 to 18 gsm (grams per square meter), and most preferably from 5 to 15 gsm. This includes, but is not limited to, embodiments where the functional layer is added to the fibers at the size press and/or coater.
• the amount of functional layer include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25 gsm, including any and all ranges and subranges therein.
• the functional layer may contain any crosslinker.
• a preferable crosslinker is one such as Cartabond TSI.
• the functional layer may contain a pigment which can act as an anti-blocking agent. Any clay or anti-blocking agent is acceptable. A preferable pigment is a clay. A preferable clay is one such as NuClay. Still further, the functional layer may contain a defoamer.
• the crosslinker may be present from 0.1 to 10 ppm based on the total weight of the functional layer, preferably 0.1, 0.2, 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 3, 4, 5, 6, 7, 8, 9, and 10 ppm based on the total weight of the functional layer, including any and all ranges and subranges therein.
• the pigment may be present from 50 to 150 ppm based on the total weight of the functional layer, preferably 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, and 150 ppm based on the total weight of the functional layer, including any and all ranges and subranges therein.
• the defoamer may be present from 50 to 150 ppm, preferably 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, and 150 ppm based on the total weight of the functional layer, including any and all ranges and subranges therein.
• the functional layer when contacted with the fibers of the paper substrate, may have any pH, preferably from 4 to 8, including 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 and 8, including any and all ranges and subranges therein.
• the functional layer when contacted with the fibers, may have any % solids, preferably a % solids of from 1 to 65, more preferably from 10 to 60% solids, including 10, 15, 20, 2,5 30, 35, 40, 45, 50, 55, and 60% solids, including any and all ranges and subranges therein.
• the functional layer, when contacted with the fibers may have a Brookfield Viscosity @
• Figures 1-3 demonstrate different embodiments of the paper substrate 1 in the paper substrate of the present invention.
• the invention is not limited thereto these examples.
• Figure 1 demonstrates a paper substrate 1 that has a web of cellulose fibers 3 and a functional layer 2 where the functional layer 2 has minimal or no interpenetration of the web of cellulose fibers 3.
• Such an embodiment may be made, for example, when a functional layer is coated onto a web of cellulose fibers. Addition points may be at the size press or coater as well, for example.
• Figure 2 demonstrates a paper substrate 1 that has a web of cellulose fibers 3 and a functional layer 2 where the functional layer 2 interpenetrates the web of cellulose fibers 3.
• the interpenetration layer 4 of the paper substrate 1 defines a region in which at least functional layer penetrates into and is among the cellulose fibers.
• the interpenetration layer may be from 1 to 99%, preferably less than 50%, more preferably less than 25% of the entire cross section of at least a portion of the surface of the paper substrate, including 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 99% of the paper substrate, including any and all ranges and subranges therein.
• Such an embodiment may be made, for example, when a functional layer is added to the cellulose fibers prior to a coating method and may be combined with a subsequent coating method if required. Addition points may be at the size press, for example.
• Figure 3 demonstrates a paper substrate 1 that has a web of cellulose fibers 3 and a functional layer 2 where the functional layer 2 is approximately evenly distributed throughout the web of cellulose fibers 3.
• Such an embodiment may be made, for example, when a functional layer is added to the cellulose fibers prior to a coating method and may be combined with a subsequent coating method if required. Exemplified addition points may be at the wet end of the paper making process, the thin stock, and the thick stock.
• the density, basis weight and caliper of the web of this invention may vary widely and conventional basis weights, densities and calipers may be employed depending on the paper- based product formed from the web.
• Paper or paperboard of invention preferably have a final caliper, after calendering of the paper, and any nipping or pressing such as may be associated with subsequent coating of from about 1 mils to about 35 mils, although the caliper can be outside of this range if desired. More preferably the caliper is from about 4 mils to about 20 mils, and most preferably from about 7 mils to about 17 mils.
• the caliper of the paper substrate with or without any functional layer may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 20, 22, 25, 27, 30, 32, and 35, including any and all ranges and subranges therein.
• Paper substrates of the invention preferably exhibit basis weights of from about 10 lb/3000ft 2 to about 500 lb/3000ft 2 , although web basis weight can be outside of this range if desired. More preferably the basis weight is from about 301b/3000ft 2 to about 200 lb/3000ft 2 , and most preferably from about 35 lb/3000ft 2 to about 150 lb/3000ft 2 .
• the basis weight may be 10, 12, 15, 17, 20, 22, 25, 30, 32, 35, 37, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 500 lb/3000ft 2 , including any and all ranges and subranges therein.
• the final density of the papers may be calculated by any of the above-mentioned basis weights divided by any of the above-mentioned calipers, including any and all ranges and subranges therein.
• the final density of the papers is preferably from about 6 lb/3000ft 2 /mil to about 14 lb/3000ft 2 /mil although web densities can be outside of this range if desired. More preferably the web density is from about 7 lb/3000ft 2 /mil to about 13 lb/3000ft 2 /mil and most preferably from about 9 lb/3000ft 2 /mil to about 12 lb/3O ⁇ Oft 2 /mil.
• the substrate of the present invention preferably has a Cobb Value as determined by the Cobb Sizing Test, according to ASTM D-3285 (TAPPI T-441), of less than 50 g/m 2 , preferably less than 35 g/m 2 , more preferably less than 30 g/m 2 , most preferably less than 25 g/m 2 .
• the Cobb Value may be 50, 45, 40, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 g/m 2 , or less, including any and all ranges and subranges therein.
• G.A. Smook referenced above and references cited therein provide lists of conventional additives that may be contained in the paper substrate, and therefore, the paper articles of the present invention. Such additives may be incorporated into the paper, and therefore, the paper packaging (and packaging materials) of the present invention in any conventional paper making process according to G.A. Smook referenced above and references cited therein.
• the paper substrate of the present invention may also include optional substances including retention aids, sizing agents, binders, fillers, thickeners, and preservatives.
• fillers include, but are not limited to; clay, calcium carbonate, calcium sulfate hemihydrate, and calcium sulfate dehydrate.
• binders include, but are not limited to, polyvinyl alcohol, polyamide-epichlorohydrin, polychloride emulsion, modified starch such as hydroxyethyl starch, starch, polyacrylamide, modified polyacrylamide, polyol, polyol carbonyl adduct, ethanedial/polyol condensate, polyamide, epichlorohydrin, glyoxal, glyoxal urea, ethanedial, aliphatic polyisocyanate, isocyanate, 1,6 hexamethylene diisocyanate, diisocyanate, polyisocyanate, polyester, polyester resin, polyacrylate, polyacrylate resin, acrylate, carboxymethyl cellulose, urea, sodium nitrate, and methacrylate.
• optional substances include, but are not limited to silicas such as colloids and/or sols.
• silicas include, but are not limited to, sodium silicate and/or borosilicates.
• solvents including but not limited to water.
• the starch may be of any type, including but not limited to oxidized, ethylated, cationic and pearl, and is preferably used in aqueous solution.
• Illustrative of useful starches for the practice of this preferred embodiment of the invention are naturally occurring carbohydrates synthesized in corn, tapioca, potato and other plants by polymerization of dextrose units. All such starches and modified forms thereof such as starch acetates, starch esters, starch ethers, starch phosphates, starch xanthates, anionic starches, cationic starches and the like which can be derived by reacting the starch with a suitable chemical or enzymatic reagent can be used in the practice of this invention.
• Useful starches may be prepared by known techniques or obtained from commercial sources. Suitable starches include, but are not limited to, PG-280 from Penford Products, SLS- 280 from St. Lawrence Starch, the cationic starch CatoSize 270 from National Starch and the hydroxypropyl No. 02382 from Poly Sciences, Inc.
• Starches for use in the practice of this invention may be modified starches. Still further, are those starches that are cationic modified or non-ionic starches such as CatoSize 270 and KoFiIm 280 (all from National Starch) and/or chemically modified starches such as PG-280 ethylated starches and AP Pearl starches. Starches for use in the practice of this invention may be cationic starches and chemically modified starches.
• the contacting of the functional layer with the cellulose fibers may occur anytime in the papermaking process including, but not limited to the wet end, thick stock, thin stock, head box, size press and coater, with the preferred addition point being at the size press and/or coater. Further addition points include machine chest, stuff box, and suction of the fan pump. As discussed above and in Figure 3, when the functional layer components are added towards the wet end of papermaking, the functional layer may become interpenetrated and/or incorporated into the paper substrate layer containing fibers.
• the paper substrate may be made by contacting further optional substances with the cellulose fibers as well.
• the contacting may occur anytime in the papermaking process including, but not limited to the thick stock, thin stock, head box, size press, water box, and coater. Further addition points include machine chest, stuff box, and suction of the fan pump.
• the cellulose fibers, functional layer, and/or optional/additional components may be contacted serially, consecutively, and/or simultaneously in any combination with each other.
• the cellulose fibers and functional layer may be pre-mixed in any combination before addition to or during the paper- making process.
• the paper substrate may be pressed in a press section containing one or more nips.
• any pressing means commonly known in the art of papermaking may be utilized.
• the nips may be, but is not limited to, single felted, double felted, roll, and extended nip in the presses.
• any nip commonly known in the art of papermaking may be utilized.
• the paper substrate may be dried in a drying section. Any drying means commonly known in the art of papermaking may be utilized.
• the drying section may include and contain a drying can, cylinder drying, Condebelt drying, IR, or other drying means and mechanisms known in the art.
• the paper substrate may be dried so as to contain any selected amount of water. Preferably, the substrate is dried to contain less than or equal to 10% water.
• the paper substrate may be passed through a size press, where any sizing means commonly known in the art of papermaking is acceptable.
• the size press for example, may be a puddle mode size press (e.g. inclined, vertical, horizontal) or metered size press (e.g. blade metered, rod metered).
• sizing agents such as binders may be contacted with the substrate.
• these same sizing agents may be added at the wet end of the papermaking process as needed.
• the paper substrate may or may not be dried again according to the above-mentioned exemplified means and other commonly known drying means in the art of papermaking.
• the paper substrate may be dried so as to contain any selected amount of water. Preferably, the substrate is dried to contain less than or equal to 10% water.
• additives may be present as well in the size composition. These include, without limitation, dispersants, fluorescent dyes, surfactants, deforming agents, preservatives, pigments, binders, pH control agents, coating releasing agents, optical brighteners, defoamers, bulking agents such as expandable microspheres and the like.
• additives may include any and all of the above-mentioned optional substances, or combinations thereof.
• the paper substrate may be calendered by any commonly known calendaring means in the art of papermaking. More specifically, one could utilize, for example, wet stack calendering, dry stack calendering, steel nip calendaring, hot soft calendaring or extended nip calendering, etc.
• the paper substrate may contain multiple layers of cellulose fibers webs.
• the substrate contains at least three layers of cellulose fiber webs having six major surfaces or four layers of cellulose fiber webs having eight major surfaces. Any of these surfaces may be corrugated, laminated, glued, or adhered to each other in any conventional manner so as to form a multilayered substrate.
• a multilayed paper substrate may be a corrugated paper substrate.
• a corrugated paper substrate maybe made from the paper substrate of the present invention and further converted/folded/die cut into for example a package and/or shipping material that is, single layered and/or multilayered paper or paperboard material.
• the package and/or shipping material preferably comprises at least three paper substrates, each having a web of cellulose fibers and at least one of which further containing the functional layer therein and/or thereon.
• multilayered paper-based structures e.g. such as those mentioned above
• multilayered paper-based structures are formed and/or folded into shapes useful for packaging and/or shipping.
• means for connecting such layers together are required.
• Such means may be gluing, laminating, adhering and/of folding such layers together and require, in part, an adhesive.
• the paper substrate and articles made therefrom preferably contain an adhesive layer.
• Figure 6 shows one embodiment of the paper substrate of the present invention which may contain a web of cellulose fibers 3 and a functional layer 2 and an adhesive layer 5.
• the above-mentioned Figures 1-3 pertain to when the functional layer is present.
• Such embodiments may also be appropriately suited for when an adhesive layer is utilized in addition thereto.
• the web, functional layer, and adhesive layer may be one layer and/or may interpenetrate one another within an interpenetration layer 4 from 0 to 100%, respectively, and/or each independent of the other to any degree.
• the state of interpenetration for any two or more of the web, functional layer and adhesive layer may be 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 99% of the paper substrate, including any and all ranges and subranges therein.
• the adhesive layer preferably contains at least one adhesive that is suitable for adhering two layers of cellulose fiber web together. Any conventional adhesive is suitable. Examples of suitable adhesives include those known as hot melt adhesives and/or cold-set adhesives. Examples of the adhesive are those containing a polyamide, polyamide containing polymer, polyamide containing copolymer, polyethylene, polyethylene-containing polymer, polyethylene- containing copolymer, ethylene vinyl acetate, ethylene vinyl acetate-containing polymer, ethylene vinyl acetate copolymer, vinyl, polyvinyl, vinyl containing polymer, vinyl containing copolymer, poly, alpha olefin, olefin, polyolefin, olefin containing polymer, and olefin containing copolymer.
• Hot melt adhesives include those from National Starch, Hercules, Henkel, Reynolds, Arizona Chemical Company, and HB Fuller. Specific examples are Henkel 80-8795; Chief 235 HP; National Starch 34-246A; Chief 235 Plus; HB Fuller HL9254; Henkel TB9-15-5; National Starch 34-6601; National Starch 34-379A; Forbo/Swifts; Pacific; H.B. Fuller G3556; and Henkel 51-1057- FD.
• the adhesives may be used together and/or alone.
• a single adhesive when used, it is preferably that it be a hot-melt adhesive. In another preferred embodiment, when more than one adhesive is used, it is preferably that at least one hot-melt adhesive and at least one cold-set adhesive be utilized.
• the adhesives may be contained in a single layer or multiple layers and may follow the example of the substrate discussed above in relation to Figure 6 in a manner that could assume multiple different adhesive layers 5 therein Figure 6 discussed above.
• the individual adhesive layers may interpenetrate each other as well as the functional layer and/or web of cellulose fiber at any degree.
• a portion of the functional layer may intervene between the two webs at some time, which may cause a reduction in the adhesive properties of the adhesive layers thereon to adhere the webs together. Therefore, the efficiency of such converting processes may be compromised by the functionality in the functional layer present on/in the paper substrate at the time of the above-mentioned conventional converting steps.
• both the increase in surface area and the exposure methodologies in combination is an embodiment of the present invention.
• Such portions of the paper substrate maybe referred to as "treated" portions.
• Means for exposing at least a portion of at least one layer of cellulose fiber web to the adhesive layer or means for increasing the surface area of contact between the adhesive layer and the functional layer may include any means for compromising at least a portion of the functional layer.
• Such means may include, for examples, means for penetrating, abrading, skiving, boring, breaking, busting, cracking, diffusing, drilling, eating through, encroaching, entering, goring, impaling, infiltrating, inserting, piercing, knifing, perforating, permeating, pervade, pop in, pricking, puncturing, reaming, spearing, stabbing, wearing, chafing, eroding, grating, rubbing, scraping, scratching, scuffing, denting, fragmenting, nicking, notching, paring, scratching, shaving, slicing, and splintering.
• Figure 4 An example of a converted blank for a package that contains at least one substrate of the present invention is shown as Figure 4 and may also be mentioned in United States Provisional Patent Application having USSN 60/702,879, filed July 27, 2006, which is hereby incorporated in its entirety, herein by reference.
• Figure 5 is a close-up view of a portion of a flap of the package blank in Figure 4.
• an adhesive layer may be applied thereto the substrate.
• Figure 6 demonstrates a first region of the flap shown in Figure 5 that corresponds to two geographies on the flap upon which the adhesion may occur.
• Figure 6 shows an untreated portion.
• Figure 7 shows a treated portion as defined above. In this specific example, the treated portion is skived.
• the adhesive should provide an open time of from 0.5 to 5.0, more preferably 1.5 to 3.5 seconds, most preferably 1.9 to 2.5 seconds.
• the adhesive should provide a dwell time for compression of 0.25 to 1.5 second, preferably 0.5 to 1.25 seconds, more preferably from 0.65 to 0.85 seconds.
• the adhesive must satisfy the below mentioned initial fiber tear test (Hot melt Bonding Test attached below) which is the use of a Rock-Tenn hot melt simulator (see Examples) using settings of, 300 to 450 deg F, preferably from 350 to 380 deg F, the above- mentioned open time (preferably -2.5 sec open time), with the above-mentioned dwell time (preferably ⁇ 0.75 sec dwell time), and with tearing force applied immediately after dwell time to simulate springback forces during conversion of packages made from the substrate of the present invention.
• Hot melt Bonding Test attached below
• the above- mentioned open time preferably -2.5 sec open time
• dwell time preferably ⁇ 0.75 sec dwell time
• the Hot Melt Bonding Test provides a value of simulating the hog melt gluing process in the lab so as determine the effects of major variables such as substrate, adhesive, temperature, open and dwell times, and adhesive amount upon gluing.
• this test was peformed in the lab when two strips of paper are cut CD (cross direction) long: 2.5" x 8" and 1" x 8" specimens respectively.
• the adhesive is applied at the temperatures ranging from 350 to 400 degree F to the uncoated side of the 2.5" x 8" specimen with a 1.5 second of open time.
• the coated side of the second 1" x 8" is compressed onto this for 1.0 seconds of compression time.
• the samples are glued, cooled, and torn along the length of the glue bead at TAPPI Standard Conditions (73 degree F, 50% Relative Humidity).
• the first adhesive preferably a hot-melt adhesive
• the cold-set adhesive is optional. If, however, ⁇ 75% fiber tear occurs after the 4 four hour test mentioned above, then a cold set adhesive assist would be desirable in addition to the first adhesive, preferably a hot-melt adhesive.
• Packagings for fruits and vegetables have had problems with their inability to protect their handlers and the produce contained therein from deadly predators. Accordingly, it has been desirable to treat the packages so that the environment, in which they lie, while in transit to the consumer, in part results in their exposure to sulfur dioxide.
• Sulfur dioxide is known to kill predators of produce and pests of humans.
• One such pest is the black widow spider. It is necessary to keep black widow spiders away or dead when in contact with the produce package and environment. Therefore, it is desirable to have a packaging material for the product that does not absorb, adsorb, and/or chemically react with the sulfur dioxide in the shipping environment. Such interactions will inevitably reduce the amount of active sulfur dioxide within the environment; thereby reducing the efficacy of the killing/controlling pests sensitive to sulfur dioxide such as black widow spiders.
• Styrofoam the only effective packaging material to ship such produce effectively and resist the sulfur from absorbing, adsorbing, and/or chemically reacting with such material.
• Styrofoam is not environmentally friendly. Therefore, the market still demands an environment-friendly packaging material that is capable of shipping produce at low cost and not absorb, adsorb, and/or chemically react with the sulfur dioxide in the shipping environment to the point that the active sulfur dioxide is reduced so that it is ineffective in keeping pests away and/or killing them.
• the inventors have surprisingly found a cellulose-based packaging material that is capable of shipping produce at low cost and not absorb, adsorb, and/or chemically react with the sulfur dioxide in the shipping environment to the point that the active sulfur dioxide is reduced so that it is ineffective in keeping pests away and/or killing them.
• This one non-limiting embodiment of the present invention is a paper substrate containing a functional layer that specifically increases the hold-out capacity of the substrate to sulfur dioxide. Measurement of hold-out capacity is discussed below.
• the hold-out capacity is increased at least 1%, more preferably more than 5%, most preferably more than 20% as compared to substrates that do not contain this non-limiting embodiment of the functional layer.
• the inventors have surprisingly found solutions to minimize the effect of a functional layer (e.g. sulfur dioxide holdout layer in this example) of a paper substrate on the manufacturing/converting costs/problems, while maintaining functional and structural performance of a package that incorporates the substrate therein.
• a functional layer e.g. sulfur dioxide holdout layer in this example
• the sulfur dioxide testing setup is described on the next pages, including initial attempts to physically (such as taping edges of substrates) and chemically (changing the amounts and types of chemistries contained by the functional layer of the substrates tested.
• Plexiglas Box Dimensions: 14" x 11" x 8" 1232 in 3
• Glass Drager Sulfur Dioxide 20/a detection tubes are used to find residual SO 2 after a predetermined period of time.
• the amount of holdout may be greater than 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 99% holdout based upon the total amount of sulfur dioxide initially present in the atmosphere, including any ranges and subranges therein.
• a saturation point of SO 2 in the board was determined by purging the boards and then waiting 15 minutes to test SO? levels. Initially six (10" x 12") boards were used with one minute purges but it was taking too long to reach a saturation level (5ppm increase per purge), so we cut the sample to one 6" x 10" board in the chamber with 2 minute purges.
• Table 5 Pigment screening for glueabiiity. One (10' * x 12") board per test.
• FIG. 4 Residual SO2 Concentration over time using 6 boards.
• Boards are coated as usual except with a 50-57% solids solution instead of the usual 20- 30%. This should increase the dry time and force the coating to stay on top of the sheet instead of being absorbed in between the fibers
• Formulation A target: 9 lb/3 MSF (Min. 8 lbs, Max. 10 lbs) (this is 14.4 gsm)
• Formulation B target: 7 lbs/3 MSF (or as high as the machine can pick up) (this is 11.2 gsm)
• Curl control apply steam if necessary to obtain a flat board Coating width: 76" Mositure level: 4 - 6%
• Table 11 Box Construction Plan wherein the box contains three of the following
• the Boix MP-S presents a challenge in that it operates with a long open time of 1.9 to 2.5 seconds (start of glue to end of glue bead application) followed by a compression dwell time of only 0.75 seconds (time in which flaps held together by equipment) at typical operating speeds.
• the hot melt glue must stay molten during this long open time and then set up and solidify quickly during the subsequent compression time.
• Running at slower speed on the Boix would increase the compression time slightly, but reduce converting efficiency.
• the Chief 235 Plus and the HB Fuller HL 9254 may do the job of keeping the flaps of the tray together long enough for the resin adhesive to penetrate and to develop fiber tear.
• the two products by National Starch (34-6601 and 34-379A) are polyamide hot melts which have the best performance. However, they are so viscous that there may be problems delivering them through the Nordson equipment on the Boix machine and achieving a uniform length and width glue bead. Of the two, the 34-6601 is less viscous and still has very good performance. Note that these had to be applied at 380 degree F rather than 350 degree F to get them to feed through our lab Nordson setup.
• the goal of the cold set glue tests was to determine the degree of fiber tear achieved with the latex coated liner and the time to achieve complete fiber tear.
• the resin (polyvinyl acetate formulation) adhesive was applied with a 0.015-inch Bird bar to the felt side of the latex coated liner and a second specimen of the treated liner was placed felt side down onto the first strip and compressed at 0.3 psi for the duration of the test.
• the time was varied in intervals from 5 to 28 minutes and the degree of fiber tear was noted for each test.
• the table below shows the minimum time at which 100% fiber tear was noted for each adhesive:
• the HB Fuller G3556 adhesive is a high performance commercial adhesive used on folding carton grades used for reference.
• the time to develop 100% fiber tear is in the range of 10 to 30 seconds. Therefore, the latex coating significantly retards the rate of absorption of the water-based adhesives, but still achieves complete fiber tear.
• the cold-set glue adhesive is recommended at this time when used along with the hot melt glue even on the boxes to provide their high temperature resistance.
• hot melt glue alone would soften leading to pop-opens unless there was cold-set glue to provide a strong bond that can resist temperature extremes.
• the goal of the second converting trial was to evaluate the various hot melt adhesives and to produce enough trays for the long term storage
• Condition 3 represents the minimum coating cost scenario in which the single- face (74 ag) and the doubleback (62 ag) liner were coated on their outer surfaces (non-flute contacting side) and the dual arch medium (26c/26c) was uncoated.
• Condition 5 was a condition that was designed to be easier to glue on the Boix equipment as it had the latex on the medium and only the doubleback (62 ag) sides.
• the plan was to convert Condition 3 using the newer hot melt adhesives and to convert Condition 5 using the standard Henkel adhesive for comparison. As it turned out, even the Condition 5 trays had one glue flap that contained a latex coating on the DB liner side, so that it also required a higher performance hot melt.
• the standard hot melt adhesive does not bond to the latex coated portion of the glue flap, therefore this is not a viable low cost commercial solution.
• Sulfur dioxide fumigation is used by the California table grape industry for control of insects and decay in packed table grapes.
• the treatment for decay control is designed to achieve a minimum dose of 100 CT (concentration in ppm x time in hours), achieved by either a 30-minute treatment or a total utilization treatment.
• the treatment for black widow spider control is a 30-minute fumigation with 6% CO 2 and 1% SO 2 . While there is no official requirement for monitoring CTs during the black widow spider treatment, laboratory studies suggest that a CT of approximately 3,000 to 3,300 ppmhrs is required for high spider mortality.
• Cardboard packaging material generally has a high rate of sulfur dioxide absorbance. In fact, the cardboard box is no longer approved for use in the black widow spider protocol for this reason.
• CT sulfur dioxide concentrations over time
• box #3 had the best performance of the cardboard boxes and therefore subsequent tests focused on box #3. It should be reiterated that box #3 was constructed and converted from liner and medium condition #3 of Table 11 and described in more detail at page 50 above. We answered if the amount of time the grapes were in the box after harvest would influence moisture absorbance by the box and subsequent absorbance of sulfur dioxide. In this next test, we fully warmed and dried the grapes before placing them into the cardboard boxes. The grapes were held in different sets of boxes for 2, 4, 8 and 12 hours prior to 1% sulfur dioxide fumigation as described above. There were two separate boxes for each time point.
• the final test involved storing a regular untreated cardboard grape box and experimental box #3 with grapes at 0 degree C for two weeks prior to sulfur dioxide fumigation at OC.
• the boxes were weighed before and after cold storage to determine the amount of moisture gain during this time. Following storage, two boxes of each type were fumigated with 1% sulfur dioxide as described above and the CT values determined.
• Table 18 CT values following fumigation of regular cardboard grape boxes and experimental box #3 with 1% sulfur dioxide for 30-minutes at 0 degree C following two weeks of cold storage with grapes at 0 degree C.
• This graph represents the percent of sulfur dioxide in the fumigation chamber during a 30-minute fumigation with 1% sulfur dioxide.
• two boxes of the same type, untreated cardboard boxes or experimental boxes #3 were placed in the cold room for two weeks with grapes prior to loading into the fumigation chamber at a load factor of 30.8%.
• the final CTs are given in Table 18 above.
• the present invention relates to a paper substrate that is capable of making a box that has a CT of more than 2000, preferably more than 2500, more preferably more than 3000.
• These substrate is capable of being incorporated into a box that has a CT of at least 2000, 2100, 2200, 2300, 2400, 250O 5 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, and 4000, including any and all ranges and subranges therein.
• CT a CT of at least 2000, 2100, 2200, 2300, 2400, 250O 5 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, and 4000, including any and all ranges and subranges therein.
• Previous results from laboratory tests suggest these CT would provide for greater than 90% black widow spider mortality.
• the regular cardboard grape box gave a CT of 1,500 which would provide for about 50% black widow spider mortality.
• the experimental box #3 developed by International Paper has been demonstrated to absorb considerably less sulfur dioxide than the regular cardboard table grape box and is worthy of further consideration as an improved packing material for the table grape industry.
• the reduction in sulfur dioxide absorbance would likely be beneficial for decay control and black widow spider control.
• the testing was performed in an airtight chamber with air and sulfur dioxide mixture (0.7% by weight). An empty box was placed in a testing chamber and fumigated with the gas mixture until the atmosphere in the chamber was completely exchanged. After the fumigation, the concentration of the SO 2 was measured periodically using Drager tubes.
• the graph below compares results of the measurements of different boxes, m order to confirm that the chamber was sealed, the empty chamber was fumigated with the gas mixture and the concentration of sulfur dioxide was measured at 15 and 30 minutes. The SO 2 concentration remained constant within the experimental error (see the blue line on the graph below).
• the rest of the lines on the graph show sorption of sulfur dioxide by different types of boxes.
• the box with a better performance will have a flatter line, showing smaller change in the sulfur dioxide concentration.
• the Styrofoam box showed the least sorption of SO 2 as expected.
• the uncoated box caused a dramatic decrease in the sulfur dioxide concentration (orange line on the graph), which dropped more than half after only 5 minutes.
• the GP box blue line
• the Weyerhaeuser box green line
• ranges are used as a short hand for describing each and every value that is within the range, including all subranges therein.

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• 2006
  • 2006-07-11 EP EP06786763A patent/EP1913199A1/de not_active Withdrawn
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