Not applicable.
None.
The present invention generally relates to moisture resistant and water proof paper products including linerboard and corrugated board. Particularly, this invention relates to moisture resistant corrugated paper boxes used primarily in the poultry industry that are waterproofed and can be repulped and recycled to be part of the feedstock for corrugated paper products that minimizes environmental concerns.
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, the material used most often in such 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 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 is not removed from pulp fibers during the repulping and recycling processes causes severe problems 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 also 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 laminates require the installation of specialized repulping machinery that separates the pulp fibers from the coated or laminated films and/or is far more expensive in terms of operating costs and/or recycled pulp fiber yields. The action of separating the fiber from the film damages some fibers causing the fibers to be selected out of the recycled pulp and presented for reuse, while the separated film waste carries some of the fibers out of the repulpate when its adherence is not interrupted by the repulping process. Likewise, coatings and impregnating products made from or based on 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 of standard repulping processes. Moreover, boxes made from such products are not biodegradable and must be separated and deposited in separate landfill areas.
The poultry box industry has previously used wax to coat the boxes (EVA—poly (ethylene vinyl acetate) which takes a significantly long period of time to compost and leaves a chemical residue from those compounds. There appears to be little or no decomposition of higher molecular weight resin and EVA fractions.
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 being repulpable.
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 product 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 cut-outs in the side walls, and/or by flaps folded upwardly from the container bottom wall and to which the cross beam is attached.
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. The boxes, however, were only able to obtain a 30 minute Cobb value of 20-30.
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.
None of the noted references have provided a repulpable, recyclable corrugated box capable of holding iced products and being moisture 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. 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 and other foodstuffs to be rejected by the receiver of the goods and the end purchasers of the goods. The spillage also causes fluids to be discharged over the corrugated container which might 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 backed corrugated paper box product which has the outer paper liner or backer sheet surfaces coated with a copolymer styrene acrylic emulsion with the inner corrugated paper medium and liner sheets being impregnated with a hydrogenated triglyceride such as tallow or palm oil. The coated paper box is constructed with a reinforced end panel assembly, hand cut outs and covered corners ranging from about ⅝ inch to about 1⅜ inches to prevent leakage.
The present invention is easier to repulp and recycle without detriment to production equipment, processes, or manufactured product quality or performance.
It is an object of this invention to produce a paper box product which can be compacted, repulped and recycled.
It is another object of the invention to produce a poultry box which is biodegradable.
It is still another object of the invention to produce a poultry box which has superior moisture resistance and does not leak at the corners.
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.
The preferred embodiment and best mode of the invention are shown in
As used herein the following abbreviations and terms are understood to have the meanings as set forth:
The term “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.
It has been found that hydrogenated triglycerides and preferably lard or tallow triglycerides can be substituted for petroleum based paraffin waxes and wax compounds in the manufacturer of paper products. All of these application systems involve melted 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.
Poultry boxes are unique paper products that need to withstand water and poultry fluid. The present inventive poultry box is made of double backer 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). The preferred flute size used in the invention is a “C” flute having 39+/−3 flutes per lineal foot with a flute thickness of 5/32 inch. A flat liner or backer board of Kraft paper (various grades) is glued to one side of the fluted medium with a starch based adhesive and a second flat liner or backer board of Kraft paper is adhered to the other side of the fluted medium with a starch based adhesive to form a backed corrugated board as seen in
The present repulpable inventive degradable poultry box 10, a cross section of which is seen in
After impregnation of the paper liners, both liners or backers 12 and 16 are coated on their outside surfaces with a coating 18 of a styrene acrylic co-polymer water based solution ranging from about 75% to about 95% by weight mixed or blended with hydrogenated triglyceride preferably in the nature of tallow ranging from about 5% to about 25% by weight to form an emulsified coating. A most preferred embodiment of the coating 18 is about 80% by weight styrene acrylic co-polymer solution and about 20% by weight hydrogenated triglyceride which is preferably in the form of tallow or palm oil. 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 18 is a water based high solid fluid 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 of ranging from about 1.04 to about 1.6 and viscosity (cps) of about 400, a vapor density the same as water with 30 minute Cobb values of 10 or better. The coating is fast drying, recyclable, repulpable and is printable and glueable.
The term “tallow” as used herein is meant to also cover palm oil and other hydrogenated triglycerides. The present poultry box 10 is constructed using standard corrugated box making machinery as is well known in the art. As shown in
The box blank 100 as shown in
The pinched corner tab 144 ranges from ⅝ inch to about 1⅜ inch in length depending upon the length of transverse cut 141 from the bottom panel and the corner seal depth desired when the box is assembled. See
The box 10 when folded has the reinforcement panels folded inward parallel to each other with the end panels 104 and 106 being positioned on the outside of the box forming the exterior panel of the end panel assembly. As shown in
A second embodiment of the invention is 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:
This is a utility patent application claiming priority and benefit from U.S. Provisional Patent Application No. 62/265,162, filed Dec. 9, 2015.
Number | Date | Country | |
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62265162 | Dec 2015 | US |