Patent Application
20200031517
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The present invention generally relates to leak resistant and water proof paper products including linerboard and corrugated board that are environmentally friendly. Particularly, this invention relates to leak resistant corrugated paper boxes used primarily in the food industry for transporting poultry, meat, fish and produce which can be repulped and recycled after use to be part of the feedstock for other corrugated paper products.
In the manufacture of paper and paperboard and of products made from same, petroleum derived paraffin waxes and synthetic polymers have been used for many years as moisture retardants, water repellents, oil repellents, stiffeners, strengtheners, and release agents. Besides paraffin, a material often used in such paper products is polyethylene. However, other widely used polymers in the field include polymerized acrylics, vinyls, styrenes, ethylenes and copolymers or hetero-polymers of these monomers.
The paper and paperboard to which traditional wax materials are applied to control moisture is difficult and often impossible to repulp and recycle in standard paper mill processes because the petroleum derived polymers and, particularly, the petroleum waxes are non-biodegradable in mill white waters (circulated process waters) and discharge effluents. Furthermore, the residue of the petroleum waxes that are not removed from the pulp fibers during the repulping and recycling processes causes severe problems to the papermaking equipment due to buildup that occurs on the screens and felts used during the process of forming and making the paper or paperboard sheet. In addition, paper and paperboard coated or impregnated with petroleum waxes resist biodegradation and composting when disposed of in landfills and other waste disposal systems. Paper and paperboard coated or impregnated with traditional synthetic polymers and hetero-polymers are also difficult and often impossible to repulp and recycle owing to their resistance to separation from the fiber in the standard repulping processes resulting in significant fiber losses in efforts to repulp and recycle them. These products are non-biodegradable and therefore resist composting.
Water repellent packaging currently utilizes petroleum based liquid polymer coatings or polymer film laminates (including polyethylene or similar film laminates such as polyolefin, polyester, polyvinyl alcohol, polyvinyl acetate, polystyrene, polypropylene, and the like) which are recyclable after extensive treatment, All of these polymer coating and laminates require the installation of specialized repulping machinery that separates the pulp fibers from the coatings or laminated films and/or is far more expensive in terms of operating costs and/or recycled pulp fiber yields. Furthermore, the action of separating the fiber from the film damages some fibers causing the fibers to be selected out of the recycled pulp. The separated film waste carries some of the fibers out of the repulpate. In addition, coated and impregnated paper products incorporating paraffin waxes and/or similar petroleum derivatives can only be repulped for recycling in specially configured repulping equipment that removes and separates the paraffin waxes. In the laminated film repulping process, the more intense physical and chemical requirements of this repulping process coupled with the lost fibers that become trapped in paraffin wax wastes, causes the recyclable repulped fiber levels to fall far below those fiber levels required for standard repulping processes. Moreover, boxes made from such recycled repulped products are not biodegradable and must be separated and deposited in separate landfill areas.
The food box industry has previously used wax to coat the boxes (EVA—poly (ethylene vinyl acetate) used for shipping foodstuffs which takes a long period of time to compost and leaves a chemical residue from the coating compounds. There appears to be little or no decomposition of higher molecular weight resin and EVA fractions.
Many large end users such as Wal-Mart, Costco and the like are refusing to accept non-biodegradable and/or non-recyclable containers from suppliers. Also retail end users are subject to intense pressure from environmentally concerned customers or groups to use biodegradable containers. Furthermore, when food containers start to pool or collect fluid and spill or leak fluid on other containers, box crushing occurs and these crushed boxes may be returned with their contents to the seller of the goods or the receiver of the goods. Examples of end users which have such policies are KFC, US Foods, Sysco and Restaurant Depot. Alternatively, the end user themselves may be cited by health authorities. Thus, it can be seen that this is a significant problem when shipping or stacking fresh poultry, cut meats, seafood and fresh produce.
In the prior art, a number of patents have attempted to address the above noted problems but have only moved incrementally forward in solving the customer's problems. U.S. Pat. No. 6,103,308 issued Aug. 15, 2000 is directed toward a paper and paperboard coating composition using vegetable oil triglyceride as a paper coating while U.S. Pat. No. 6,201,053 issued Mar. 13, 2001 is directed toward various triglycerides mixed with catalysts for use as a waterproofing agent on paper coating.
U.S. Pat. No. 6,846,573 issued Jan. 25, 2005 discloses the use of hydrogenated triglycerides having a melting point above 50° as a coating material for the surface of paper products to improve wet strength and moisture resistance in addition to allowing the paper products to be repulpable.
U.S. Pat. No. 8,455,068 issued Jun. 4, 2013 discloses the combination of impregnation of the poultry boxes with hydrogenated triglyceride and covering the outer surface of the liners with a dimethyl or ethylene terephthalate (PET) resulting in corrugated poultry boxes which provided moisture resistance and were recyclable and repulpable.
U.S. Pat. No. 5,752,648 issued May 19, 1998 is directed toward an eight sided poultry box formed of corrugated paperboard. The lower ends of each of the four corner panels are provided with folds, which extend from the peripheral corner portions of the box bottom toward the exterior surfaces of the corner panels. The folds function as abutments and restrict rotational movement of the corner panels about their longitudinal axes occasioned by compressional forces generated on the box ends during shipment and handling. This box is widely used in the industry but allows corner leakage which causes corner crushing and panel tearing when the boxes are stacked.
U.S. Pat. No. 7,413,111 issued Aug. 10, 2008 is directed toward a container for storing and shipping produce which is reinforced with at least one cross beam extending across the bottom wall of the container to form a bridge under loose produce placed in the container to support at least a portion of the weight of the product and prevent sagging of the container bottom. The cross beam is positioned and held in place by engaging the ends of the cross beam in recesses formed by crushed areas on an inner surface of opposing side walls, or in cut outs in the side walls, and/or by flaps folded upwardly from the container bottom wall to which the cross beam is attached.
None of the noted references have provided a reliable, repulpable, recyclable corrugated box capable of holding fresh poultry, meats, seafood and produce and being leak resistant while maintaining crush and tear strength. All of these corrugated boxes are susceptible to corner leaks which spill out of the box chamber reducing box tear strength and increasing corner crushing. As an example, typically, poultry boxes are stacked seven layers high with seven boxes forming each layer. The prior art boxes allow collection of moisture and have leakage at the corners causing stacked boxes to crush and tear with spillage of the contents at the corners which results in boxes of poultry, meat, seafood, produce and other foodstuffs being rejected by the receiver of the goods and/or the end purchasers of the goods. The spillage also causes fluids to be discharged which can present a health hazard or contaminate foodstuffs in other containers.
The present invention has been developed to solve these problems in the industry.
The present invention is directed to a repulpable recyclable leak resistant corrugated paper box which has the paper liner or backer sheet surfaces coated with a copolymer styrene acrylic emulsion with the backer sheets and inner corrugated paper fluted medium being impregnated with an animal or vegetable hydrogenated triglyceride. In one embodiment of the invention, the coated paper box is constructed with a bottom panel, side panel's assemblies which are integral to the bottom panel and end panels which are integral to the bottom panel. A plurality of insert members are glued to side panels and end panels of the box and together with corner tabs form leak resistant corners. Overlapping top panels are integral with the side panels and form the lid for the box.
In another embodiment of the leak resistant paper box without insert members, the side assembly panels have end reinforcement members which are glued to the end panels and have pre-cut corner sealing tabs.
It is an object of the invention to provide a leak resistant paper food container which is easier to repulp and recycle without detriment to repulping production equipment, processes, or manufactured product quality or performance.
It is further object of this invention to produce a leak resistant paper leak resistant cardboard food box product which can be compacted, repulped and recycled.
It is another object of the invention to produce a leak resistant paper food box which is biodegradable.
It is still another object of the invention to produce a leak resistant paper food box which has superior moisture resistance and does not leak at the corners.
It is yet another object of the invention to produce a leak resistant cardboard food box which has greater corner crush strength.
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein.
One preferred embodiment of the inventive leak resistant cardboard box invention is shown in
As used herein the following abbreviations and terms are understood to have the meanings as set forth:
The term “Hydogenated Triglyceride” includes both animal fats and vegetable oils and is derived from one or more of them. Animal fats include beef tallow, pork lard, poultry grease and fish oils. Vegetable oils include palm oil, soybean oil, peanut oil, olive oil, coconut oil and cottonseed oil.
The term “Paraffin” is a wax-like product derived from petroleum.
The terms “Paper” and “Paperboard” includes substrates and surfaces of cellulosic material.
The term “Food Boxes” refers to corrugated cardboard boxes which are used to transport fluid carrying foods such as poultry, butchered meats, beef, pork, lamb, seafood and produce.
It has been found that hydrogenated triglycerides can be substituted for petroleum based paraffin waxes and wax compounds in the manufacture of paper products. All of these application systems involve melted hydrogenated triglycerides held at temperatures in the range from around 125° F. to 170° F. which is either squeezed, rolled, cascaded, sprayed, or doctored onto the linerboard, paper, carton stock, or corrugated medium surface to impregnate the same.
The method and machinery or equipment for repulping and recycling scrap paper in the paper and paperboard or liner board industry is both an established and well known art, and the equipment required is standard and commonly installed at most mills incorporating recycled paper in their manufacturing feed stocks. Thus, those skilled in the paper making art are also knowledgeable in re-pulping and recycling.
Food boxes are unique paper products that need to withstand water, poultry fluid, meat fluid, seafood fluid and produce fluid. The present inventive food box is made of double backed corrugated board having a corrugated medium of 30 to 40 lb./1000 sq. ft. (MSF) paperboard of an “A”, “B”, “C”, “E” and “F” flute size (weight depends upon various external factors).
A flat liner or backer board of Kraft paper (various grades) which has been impregnated with hydrogenated triglyceride and coated with a biodegradable water resistant plastic copolymer is glued to one side of an impregnated fluted medium with a starch based adhesive and a second flat liner or backer board of Kraft paper which has been impregnated with hydrogenated triglyceride and coated with a biodegradable water resistant plastic copolymer is adhered to the other side of the impregnated fluted medium with a starch based adhesive to form a backed corrugated board. The preferred flute size used in the Food Box invention is a “C” flute having 39+/−3 flutes per lineal foot with a flute thickness of 5/32 inch. The Kraft paperboard liner 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. 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 from the bottom by hot plates and the adhesive holding components of the structure is cured.
The inventive present repulpable degradable leak resistant food box 20 as shown in
Both liners or backers are coated on their outside surfaces with a coating of a styrene acrylic co-polymer water based solution ranging from about 75% to about 95% by weight. The coating emulsion is heated and mixed at the general time of application and heated to a temperature from about 160° F. to about 180° F., preferably at about 170° F.
The coating (not shown) is a styrene acrylic co-polymer solution (% by weight of the styrene acrylic co-polymer ranging from about 50% to about 55% most preferably about 52%) and has a pH ranging from about 8-9 with fully cured Tg of +7, a specific gravity ranging from about 1.04 to about 1.6 and viscosity (cps) of about 400. The coating has a vapor density the same as water with 30 minute Cobb values ranging from about 25 to about 35. The coating thickness is 3 lbs. per thousand square feet (MSF) and is fast drying, recyclable, repulpable, printable and glueable.
The inventive corrugated food box 20 is shown assembled in
The box blank 22 is a unitary double backed cardboard sheet manufactured as previously discussed which is cut and scored in a box cutting station to form a bottom or base panel member 44 with foldable end members 46 which are folded upward perpendicular from the bottom planar base 44 along fold lines 48. Each end member 46 is formed with foldable tab member 50 on each side which is scored at a 45° angle leading from the end member base section 55 at the intersection of fold lines 48 and 62 to the midpoint of the end member 46 at the beginning of the end member top section 54. The tab member 50 has a fold line 51 running down its middle which intersects the tab member into two identical sections 52 and 53. Tab section 53 is connected to side panel end tab 66 and its function will be described in the side panel description. The end member 46 has a top section 54 extending vertically upward from planar surface of the base member 44 and has a linear top end edge 56 which is parallel to the surface of the base member 44.
Side panels 60 are integrally connected to the bottom member or base 44 and folded perpendicular to the base planar surface along fold lines 62. Each side panel 60 has a foldable tab section 53 which is scored at a 45° angle from the intersection of fold lines 48 and 62 and is folded together with tab section 52 along tab mid-fold line 51 inward into the box chamber to engage the end opposite tab section 52. Tab section 52 and tab section 53 together form a 90° angle on the blank.
The folding of end tab 66 of the side panel along fold line 48 and the side panel side panel 60 along fold line 62 positions the end tab 66 adjacent the top section surface 54 and directly over the linear top end edge 56 of end member 46. The end tab 66 forward edge 70 extends from its position adjacent the linear top end edge 56 upward so that the end tab linear top edge 73 is aligned with the top edge 93 of the center panel 92 of insert member 30 when the insert member 30 is glued to the interior of the box as seen in
The insert member 30 for the box is shown in
The cover of the box 20 consists of overlapping rectangular panels 82 and 82′ each of which is integral to one of the side panels 60. The cover panels 82 and 82′ are folded inward along fold lines 84 to overlap and form the cover for box 20. Each cover panel 82 has a rectangular tab 86 extending outward from the end of the cover panel. The tabs 86 each define a rounded corner 88 as seen in
The corrugated material forming the box 20 and insert members 30 are impregnated and coated in the same manner as previously described.
Another embodiment of the invention is an alternative leak resistant corrugated box 200 as shown in
Side wall panels 210 and 212 are positioned on opposite sides of bottom panel 202 and are integral thereto being joined to the bottom panel 202 along their respective fold lines 211 and 213 allowing the side panels 210 and 212 to be folded upward and positioned transverse to the plane of the bottom or base panel 202. Each of the ends of the side panels 210 and 212 is integral with end reinforcing panels 220 and 222 and is joined to the end reinforcing panels by fold lines 221 and 223. The end reinforcing panels 220 and 222 are positioned on opposite ends of each of the side panels 210 and 212 and each end reinforcing panel defines a U-shaped cut out 228 in its distal end which fits adjacent to and around slightly less than ½ of the respective end panel cut out 208 leaving a gap 223 as shown in
The pinched triangular shaped corner tab 300 ranges from ⅝ inch to about 1⅜ inch in length depending upon the length of angular cut 301 into the end panel and the corner seal depth desired when the box is assembled. The angular cut 301 is preferably at a 45° angle to fold line axis 211 or 213. The triangular shaped corner tab 300 preferably is crushed in the blank by the die as previously noted to allow easier folding. It should be noted that end reinforcing panel fold lines 221, 223 and the end panel fold line 205, 207 are offset 1/16 inch to 3/16 inch as shown in the
The box 200 when folded has the reinforcement panels 220 and 222 folded inward and aligned to each other and parallel to the end panels 204 and 206. The end panels 204 and 206 are positioned on the outside of the box forming the exterior panel of the end panel assembly. All four reinforcing panels 220 and 222 are provided with a partial hand cut outs 228 which align with the hand cut outs 208 of end panels 204 and 206 when the box is assembled. As shown in
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:
