LAMINATED MOISTURE RESISTANT POULTRY BOX AND PROCESS

Abstract

A moisture resistant poultry box having a composite structure with a fluted paper medium, a top backing board assembly secured to one side of the fluted medium and a bottom backing board assembly secured to the other side of the fluted medium. The backing board assemblies and the fluted medium are impregnated with a hydrogenated triglyceride, and each backing board assembly has PET film glued thereto covering an outside surface to provide moisture resistant recyclable poultry box so that it has a Cobb value ranging between about 0 to about 1.

Claims

1. A recyclable moisture resistant paper product comprising a structure with a fluted medium, a top paper backing liner with a sheet of biodegradable polyethylene terephthalate (PET) ranging in thickness from about 8 microns to about 20 microns glued to on an outer surface of said top paper backing liner to provide moisture resistance and wet strength to the formed liner assembly, said paper backing liner being secured to flutes on one side of said fluted medium, a bottom paper backing liner with a sheet of biodegradable polyethylene terephthalate (PET) ranging in thickness from about 8 microns to about 20 microns glued to on an outer surface of said bottom paper backing liner to provide moisture resistance and wet strength to the formed liner assembly, said bottom paper backing liner being secured to flutes on the other side of said fluted medium, with at least one of said paper backing liners and said fluted medium being impregnated with a hydrogenated triglyceride or a blend of natural, partially and fully hydrogenated triglycerides, said paper product being recyclable and having a 30 minute Cobb value ranging from about 0 to about 5.

2. The recyclable moisture resistant paper product of claim 1 wherein the hydrogenated triglyceride is an animal fat selected from the group consisting of beef tallow, pork lard, poultry grease, and fish oils.

3. The recyclable moisture resistant paper product of claim 1 wherein said paper product has a Cobb value ranging from about 0 to about 1.

4. The recyclable moisture resistant paper product of claim 1 wherein the hydrogenated triglyceride is a vegetable oil selected from the group consisting of soybean oil, peanut oil, olive oil, palm oil, coconut oil and cottonseed oil.

5. The recyclable moisture resistant paper product of claim 1 wherein said glue holding the backing liner and PET sheet together ranges from about 2 GSM to about 5 GSM.

6. The recyclable moisture resistant paper product of claim 1 wherein at least one of said backing liners has a plurality of sheets.

7. A recyclable moisture resistant corrugated paper box intended for use in packaging poultry comprising a corrugated paper product having a composite structure with a fluted paper medium and laminated liner sheet assemblies secured to each side of said fluted paper medium, each of said laminated liner sheet assemblies being formed of a paper liner sheet and a plastic film glued to said paper liner sheet with said paper liner sheet of said laminated liner sheet assembly being secured to an opposite side of said paper medium, said glue ranging in thickness from about 2 GSM to about 10 GSM, said paper liner sheet of said liner sheet assemblies and said fluted medium being impregnated with hydrogenated triglyceride, said plastic film being formed of a polyethylene terephthalate, and said corrugated box having improved moisture resistance with a 30 minute Cobb value ranging from about 0 to about 1.

8. The recyclable moisture resistant corrugated paper box of claim 7 wherein said fluted paper medium is a plurality of different sized flutes.

9. The recyclable moisture resistant corrugated paper box of claim 7 wherein said hydrogenated triglyceride is an animal fat selected from the group consisting of beef tallow, pork lard, poultry grease, and fish oils.

10. The recyclable moisture resistant corrugated paper box of claim 7 wherein said hydrogenated triglyceride is beef tallow.

11. The recyclable moisture resistant corrugated paper box of claim 7 wherein said fluted paper medium is a double wall sheet.

12. The recyclable moisture resistant corrugated paper box of claim 7 wherein said hydrogenated triglyceride is a vegetable oil selected from the group consisting of soybean oil, peanut oil, olive oil, palm oil, coconut oil and cottonseed oil.

13. The recyclable moisture resistant corrugated paper box of claim 7 wherein said hydrogenated triglyceride is palm oil.

14. A process for making a recyclable box for containing food on an inline corrugator comprising the steps of: a). coating a moving first paper liner on an inline corrugator with a coating of glue on one side; b). applying an ethylene terephthalate film to said glue coating on said first paper liner at a speed equal to the speed of said first paper liner to form a first laminated liner assembly in said corrugator; c). impregnating said first paper liner of said first liner assembly on an inline corrugator with hydrogenated triglyceride; d). impregnating a fluted paper medium on a corrugator with hydrogenated triglyceride; e). securing said first laminated liner assembly to said fluted paper medium; f). coating a moving second paper liner of a second laminated liner assembly on an inline corrugator with a coating of glue on one side; g). applying an ethylene terephthalate film to said second paper liner glue coating at a speed equal to the speed of said second paper liner to form a second laminated liner assembly in said corrugator; h). impregnating said second paper liner of said second liner assembly on an inline corrugator with hydrogenated triglyceride; i). securing said second laminated assembly to said fluted paper medium to form a fluted medium with a secured laminated liner board assembly on both sides of said fluted medium; and j). curing said composite medium and secured first and second liner board assemblies to form corrugated box material.

15. A process as claimed in claim 14 including the additional step k) scoring and cutting said corrugated box material to form a box blank.

16. The process of claim 14 wherein said hydrogenated triglyceride is an animal fat selected from the group consisting of beef tallow, pork lard, poultry grease, and fish oils.

17. A process as claimed in claim 14 wherein in steps b) and g), said glue is applied to said paper liner sheets at about 2 GSM to about 10 GSM.

18. The process of claim 14 wherein said hydrogenated triglyceride is a vegetable oil selected from the group consisting of soybean oil, peanut oil, olive oil, palm oil, coconut oil and cottonseed oil.

19. A process for making a moisture resistant recyclable poultry box on an inline corrugator comprising the steps of: a). applying a glue coating ranging from about 2 GSM to about 10 GSM to a first liner sheet of paper; b). securing a polyethylene terephthalate film to said first liner sheet glue coating to form a laminated liner assembly; c). impregnating said first liner sheet of paper of said laminated liner assembly with a hydrogenated triglyceride; d). impregnating a fluted paper medium from in an inline corrugator with hydrogenated triglyceride; e). applying a glue coating ranging from about 2 GSM to about 10 GSM to a second liner sheet of paper; f). securing a polyethylene terephthalate film to said second liner sheet glue coating to form a second laminated liner assembly; g). impregnating a second liner sheet of paper of said second laminated liner assembly with hydrogenated triglyceride; h). securing said laminated liner assembly to said fluted paper medium; i). securing said second laminated liner assembly to said fluted paper medium to form a composite corrugated structure with each laminated liner assembly's polyethylene terephthalate film forming an outside surface of said composite corrugated structure; j). curing said composite corrugated structure to cure said glue coatings; and k). cutting said composite corrugated assembly into separate pre-sized poultry box blanks which have a 30 minute Cobb value ranging from about 0 to about 1.

20. A process as claimed in claim 19 wherein tips of said fluted paper medium are coated with a starch to secure said adjacent laminated assemblies.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a schematic diagram of the inline corrugator used in making the laminated corrugated material of the invention;

[0035] FIG. 2 is a reduced view of the inline corrugation process of the invention;

[0036] FIG. 3 is an enlarged view of FIG. 2 taken from bracket A of FIG. 2 showing the lamination and impregnation of the of the initial liner assembly in an inline corrugation process;

[0037] FIG. 4 is an enlarged view of FIG. 2 taken from bracket B of FIG. 2 showing the coater, infrared dryer, formation of the fluted medium, impregnation of the medium and securing the initial laminated liner assembly to the fluted medium in an inline corrugation process;

[0038] FIG. 5 is an enlarged view of FIG. 2 taken from bracket C of FIG. 2 showing the formation of the alternate sized fluted medium, impregnation of the liner and securing the initial laminated liner backer to the fluted medium in an inline corrugation process;

[0039] FIG. 6 is an enlarged view of FIG. 2 taken from bracket D of FIG. 2 showing the lamination and impregnation of a second liner assembly in an inline corrugation process;

[0040] FIG. 7 is an enlarged view of FIG. 2 taken from bracket E of FIG. 2 showing the securing of the second liner assembly to the medium and curing the corrugated board in an inline laminated corrugation process; and

[0041] FIG. 8 is an enlarged cross sectional view of the inventive corrugated board taken across the machine direction of the finished laminated corrugated board material.

DETAILED DESCRIPTION OF THE INVENTION

[0042] The preferred embodiments and best mode of the invention are shown in FIGS. 1 through 8. While the invention is described in connection with certain preferred embodiments, it is not intended that the present invention be so limited. On the contrary, it is intended to cover all alternatives, modifications, and equivalent arrangements as may be included within the spirit and scope of the invention as defined by the appended claims.

I. Definitions

[0043] As used herein the following abbreviations and terms are understood to have the meanings as set forth:

[0044] The term “Hydrogenated Triglyceride” includes both animal fats and vegetable oils and is derived from one or a mixture of the animal fats and/or vegetable oils. Animal fats include beef tallow, pork lard, poultry grease and fish oils. Vegetable oils include soybean oil, peanut oil, olive oil, palm oil, coconut oil and cottonseed oil.

[0045] The term “Paper” includes substrates and surfaces of cellulosic material.

[0046] The term “PET” is a film formed from a thermoplastic resin consisting of polymerized units of the monomer dimethyl terephthalate or polyethylene terephthalate, with repeating C.sub.10H.sub.8O.sub.4 units formed in a laminating sheet.

[0047] The term “moisture resistant” means the tendency of a material to repel or not absorb or transmit liquid in normal use. The term includes moisture repellant and other terminology which means substantial water blocking capabilities or properties as opposed to total water blocking capabilities or properties.

[0048] It has been found that hydrogenated triglycerides and preferably either tallow or palm oil can be impregnated into the paper components of the corrugated board, namely, the medium and liners with the outer surface of each liner being covered with a polyester PET film which is glued to the respective liner. This combination can be substituted for petroleum based paraffin waxes and wax compounds in the manufacture of recyclable, paper products and in particular, mediums and liner board of corrugated cardboard. All of these application systems involve melted hydrogenated triglycerides held at a temperature ranging from about 125° to about 170° F. The hydrogenated triglycerides are either squeezed, rolled, cascaded, sprayed, or doctored onto the linerboard, paper, carton stock, or corrugated medium surface to impregnate the same.

[0049] Poultry boxes are unique paper container products that need to withstand water and poultry fluid.

[0050] A preferred embodiment of the inventive moisture resistant poultry box (not shown) according to the invention is constructed from a single corrugated board 11, as shown in cross section in FIG. 8, having a paper fluted medium 12 impregnated with a hydrogenated triglyceride, preferably tallow or palm oil at 3.5 lbs/MSF and the outer paper liner backers 14 and 16 impregnated with the same hydrogenated triglyceride at 2.5 lbs/MSF. Palm oil and tallow used in the impregnation is commercially available from C.J. Robinson Co. and Chemol Corporation.

[0051] The corrugated medium 12 is constructed of 30 to 40 lb./1000 sq. ft. (MSF) paperboard in an “A”, “B”, “C”, “E” and “F” flute size (weight depends upon various external factors). The preferred flute size used in the invention is an “A” flute having 33+/−3 flutes per lineal foot with a flute thickness of ⅜ inch or a “C” flute having 39+/−3 flutes per lineal foot with a flute thickness of 5/32 inch.

[0052] The outer tip surfaces of the medium flutes 13 are coated with a starch 15 which is applied as is known in the art to hold the laminated liner assemblies 22 in place on the medium 12 once they engage the flute tips. Each laminated liner assembly 22 comprises a paper liner backer 14/16 upon which a plastic film 18, preferably polyethylene terephthalate (PET) having a thickness ranging from about 0.008 mm to about 0.020 mm (8 to 20 microns), most preferably about 0.008 mm to about 0.012 mm (8 to 12 microns) is glued 20 as will be described in more detail to the outer surface of the paper liners 14 and 16 to form laminated liner assemblies 22. The laminated liner assembly 22 is secured by the starch 15 applied to the flute tips of the fluted medium 12 to form the laminated corrugated board 11 used as the box blank. A cross section of the corrugated board 11 is best shown in FIG. 8.

[0053] In operation, the laminated corrugated poultry box is constructed using standard corrugated box making machinery such as an inline corrugator which is schematically shown in FIG. 1. The entire process can be run on an inline corrugator without speed constraints up to 1000 feet per minute. A roll 102 of thermoformed plastic film 112 preferably a smooth sided polyethylene terephthalate is positioned upstream adjacent roll 104 of liner paper 114 and upstream of the glue head assembly 120. Suitable polyester PET film can be acquired from Filmquest Inc. under the trademark QUESTAR® and from Tekra Corporation, a wholly owned subsidiary of Genuine Parts Company. Both the liner paper 114 and the plastic film 112 are individually pulled off the respective rolls 102, 104 by a nip roller and a glue head assembly 120 which applies a thin layer of glue ranging from about 2 GSM to about 10 GSM, preferably about 2 GSM to about 5 GSM in thickness and most preferably about 4 GMS in thickness on the outer surface of the liner paper 114 to hold plastic film 112 secured in place on the liner paper 114. The glue is directly applied as a continuous layer on the liner paper. The preferred glue used to secure the PET film sheet to the paper liners is a cold glue AQUENCE® manufactured by Henkel Corporation which has a solids content of about 55%, a viscosity of 1500 cps and a pH of about 4.5 and is applied at room temperature. Alternatively, a hot melt glue TECHNOMELT® manufactured by Henkel Corporation may be used. This polyamide glue has viscosity of ranging between 3,500 to 4,500 cps and a melt temperature ranging from about 200° C. to about 400° C. The plastic polyethylene terephthalate film 112 travels at the same speed as the liner paper 114 and is aligned with the plastic film 112 and pressed together in roller assembly 120 gluing the liner paper 114 and plastic film 112 together into a unitary composite laminated liner assembly 122. The laminated liner assembly 122 is passed through impregnator 130 which impregnates the paper of the laminated liner assembly and is wound around a heated drum assembly 135 which is heated on its surface to control the temperature of the laminated liner assembly 122. The laminated liner assembly 122 passes through coater 136 and is then passed over infrared dryer 138 over curer drum 139 into the corrugating machine 140.

[0054] As shown in FIG. 4, paper medium 216 is pulled from roll 204 located downstream from paper roll 104 through impregnator 142 to impregnate the medium 216 with hydrogenated triglyceride. The paper medium 216 is carried around heated drum assembly 144 into the flute forming corrugating machinery 140 along a top conveyor 148 which deposits the fluted medium 116 on top of the laminated backer sheet 122 carried by bottom conveyor 146 of the corrugating machinery (see FIG. 4). The tips of the flutes of the fluted medium 216 engage the paper 114 of liner assembly 122 carried by lower conveyor 146 of the laminated backer sheet.

[0055] The laminated liner assembly 122 is preferably constructed of Kraft paper 114 (various grades) with the laminated plastic PET film 112 glued thereto. The paper 114 is adhered to one side of the fluted medium 216 with a starch based adhesive to form a polyethylene terephthalate (PET) laminated backed corrugated board. The Kraft paperboard liner 114 may be bleached white, coated white (white coat), mottled white or colored. As is well known in the art, the medium paper is humidified by means of high pressure steam which softens the paper fibers to facilitate the formation of the flute and consequent gluing. The paper medium 216 is taken from roll 204 though the corrugator flute forming machine 140 as is well known in the art to make a flute of the desired size such as “A” which is attached as to the laminated backer sheet 122 noted above by starch. After formation of the board, this humidity is removed by drying in the dry-end. In the present invention, the newly formed corrugated liner board is heated by hot plates and the adhesive holding components of the structure is cured.

[0056] A second roll of paper 304, as shown in FIG. 5, dispenses paper 314 for forming a second fluted medium 316 preferably of a different flute size from medium 216 (as for example, flute size allowing the medium flute size to be changed on the inline corrugator to “C” from “A”). The fluted paper medium 316 is located downstream, but adjacent to roll 204 and can be converted into fluted medium 316 in a second corrugator flute forming machinery 160 as a back up to the first flute forming machinery 140 or as a second corrugated flute used to build a double wall sheet or for a different size flute. Thus, it can be seen that the technology applies to single wall, double wall or even triple wall sheets. The medium 316 passes from roll 304 through an impregnator assembly 150 which impregnates medium with hydrogenated triglyceride with the medium being transported past dryers 152 into coater 154 and past infrared dryer 156 and dryer 158.

[0057] As shown in FIG. 6, second roll 404 of the liner paper 414 is positioned downstream from the medium flute forming machinery 240 but upstream from film roll 402. The film roll 402 contains thermoformed plastic film 412, preferably polyethylene terephthalate. Both the liner paper 414 and the plastic film 412 are individually pulled off the respective rolls 404, 402 with the liner paper 414 being pulled off the roll through impregnator 170 and dryer 172 by nip rollers around a second glue head 175 which applies a thin layer of glue ranging from about 2 GSM to about 10 GSM, preferably about 4 GSM in thickness on the outer surface of the liner paper 414 to hold the plastic film 412 in place on the liner paper 414. The plastic film 412 travels at the same speed as the liner paper 414 and is aligned with the plastic film 412 and pressed together in glue and nip roller assembly 175 gluing the liner paper 414 and plastic film 412 together into a unitary composite laminated liner assembly 430.

[0058] The laminated liner assembly 430 is run through an impregnator 177 which impregnates the liner paper 414 of the second laminated liner assembly 430 with hydrogenated triglyceride. The impregnated liner assembly 430 is carried past a heater drum 179 and a stacked heater assembly 180 where the adhesive is cured. As seen in FIG. 7, liner assemblies and medium are run through an adhesive machine 182 into the assemblies 184 which apply starch to the tips of the fluted medium. The liner assemblies and medium are pressed together to form assembly 184 which forms the laminated corrugated board. The corrugator board 11 is passed into a hot plate curing section 190 and the cured corrugated board is cut into box blanks.

[0059] The PET film is applied to the outside top and bottom surfaces of the respective liner assemblies and are secured to the medium forming a laminated corrugated board. The laminated corrugated composite board 11 as seen in FIG. 8 is then passed over a heat curing bed 190 to cure and set the adhesive or glue and the laminate. The PET film applied to the outer surface of each liner assembly is of the same thickness.

[0060] The heat curing bed 190 is a series of hot plates and pressure rollers which applies light pressure and heat to cure the laminate and adhesive. The composite laminated corrugated board is then scored and cut into individual box blanks in a scoring, cutting and stacking station 200 (shown in FIG. 1) and is well known in the art with known means stacking the individual flat sheets of composite corrugated board. The individual composite corrugated blanks are stacked and dried for a day. The blanks are later placed in a standard box cutting station which cuts and scores the blanks so that they can be folded into the desired box.

[0061] The poultry box blanks after being scored and cut at cutter 200, as seen in FIG. 1, and are then delivered and assembled at the poultry or food packing plant and assembled to provide a structurally sound moisture proof box. This box is assembled and tested had a 30 minute Cobb value ranging between 0 to about 10, more preferably ranging from about 0 to about 5 and most preferably ranging from between 0 to about 1.

[0062] Testing of the poultry boxes when compared with boxes without impregnated liners showed that hydrogenated triglyceride impregnated boxes had a 7% higher ECT Compression strength and retained 66% of their dry strength compression under 5 days simulated ice pack conditions as opposed to 54% of dry strength compression with non-impregnated liners. Box compression tests were at ambient temperature for simulated ice pack conditions (40 lbs. brick with 10 lbs. of ice).

[0063] As previously noted the plastic sheet used in the laminated board backer is a polyethylene terephthalate (PET) film consisting of polymerized units of the monomer dimethyl terephthalate or ethylene terephthalate, with repeating C.sub.10H.sub.8O.sub.4 units is glued to the liners of the corrugated material. PET contains the chemical elements carbon, hydrogen, and oxygen and has a tensile strength ranging from 55-75 MPa. If fully burned, it produces only carbon dioxide (CO.sub.2) and water (H.sub.2O) and contains no Sulphur. PET is commonly recycled, and has the number “1” as its recycling symbol.

[0064] The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. However, the invention should not be construed as limited to the particular embodiments which have been described above. Instead, the embodiments described here should be regarded as illustrative rather than restrictive. Variations and changes may be made by others without departing from the scope of the present invention as defined by the following claims: