Repulpable corrugated box with styrene-acrylic copolymer and hydrogenated triglyceride coating

Abstract

A repulpable moisture resistant poultry box having a composite structure with a fluted medium, a top backing board secured to one side of the fluted medium and a bottom backing board secured to the other side of the fluted medium. The backing boards and the fluted medium are impregnated with a hydrogenated triglyceride. The backing boards each have an outer surface coated with an emulsion of hydrogenated triglyceride and styrene acrylic to provide moisture resistance repulpable and recyclable box.

Claims

1. A repulpable moisture resistant paper product without wax content comprising a composite corrugated paper structure with a fluted medium, a top paper backing liner secured to one side of said fluted medium and a bottom paper backing liner secured to 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, at least one of said impregnated paper backing liners having an outer surface coated with an emulsified mixture of styrene acrylic copolymer and hydrogenated triglyceride to provide moisture resistance and wet strength to said paper product, said paper product being repulpable, recyclable and compostable.

2. The repulpable moisture resistant paper product of claim 1 wherein the hydrogenated triglyceride is tallow.

3. The repulpable moisture resistant paper product of claim 2 wherein said tallow is about 20% by weight of said emulsified mixture.

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

5. The repulpable 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.

6. The repulpable moisture resistant paper product of claim 1 wherein the emulsified coating mixture ranges from about 75% to about 95% by wet coating weight of styrene acrylic copolymer with the remainder by weight being hydrogenated triglyceride.

7. The repulpable moisture resistant paper product of claim 6 wherein said emulsified coating is applied to the outer surfaces of said paper backing liners at a wet coating weight in a range of about 1.0 to about 2.0 lbs. per thousand square feet of liner board surface.

8. The repulpable moisture resistant paper product of claim 1 wherein the paper product is a recyclable moisture resistant corrugated poultry box.

9. The repulpable moisture resistant paper product of claim 1 wherein said fluted medium has a C flute size.

10. The repulpable moisture resistant paper product of claim 1 wherein said fluted medium has an A flute size.

11. The repulpable moisture resistant paper product of claim 1 wherein the hydrogenated triglyeerlde is palm oil.

12. A waxless repulpable recyclable moisture resistant paper box intended for use in wet food processing conditions comprising a corrugated paper product having a composite structure with a fluted medium and liner sheets secured to each side of said medium, said liner sheets and fluted medium being impregnated with animal hydrogenated triglyceride and said liner sheet's outer surfaces being coated with an emulsified mixture of styrene acrylic copolymer and hydrogenated triglyceride, said coating having a hydrogenated triglyccride content ranging from about 5% to about 25% by wet coating weight and a pH ranging from about 8 to about 9, imparting improved moisture resistance and wet strength to said paper box allowing said paper box to be repulpable and recyclable.

13. The repulpable paper box of claim 12 wherein said animal hydrogenated triglyceride is an animal fat selected from the group consisting of beef tallow, pork lard, poultry grease, and fish oils.

14. The repulpable paper box of claim 12 wherein said emulsified coating mixture is at least 75% by weight styrene acrylic solution with the remainder by weight being animal hydrogenated triglyceride.

15. The repulpable paper box of claim 12 wherein said emulsified coating mixture is applied to the outer surfaces of said paper liner sheets at a coating weight in a range of about 1.0 to about 2.0 lbs. per thousand square feet of liner surface.

16. The repulpable poultry box of claim 12 wherein said paper box is a moisture resistant poultry box.

17. A wax-free repulpable recyclable moisture resistant poultry box comprising a corrugated paper composite structure with a paper fluted medium and paper liner sheets secured to each side, said paper liner sheets and paper fluted medium being impregnated with tallow ranging from about 2.5 to about 3.5 lbs/MSF with at least one of said paper liner sheet's outer surfaces being coated with an emulsion of about 80% styrene acrylic mixed in water by weight and about 20% tallow by weight, said emulsion coating imparting improved moisture resistance and wet strength to said poultry box.

18. The repulpable poultry box of claim 17 wherein said fluted medium has a C flute size.

19. The repulpable poultry box of claim 17 wherein said fluted medium has an A flute size.

20. A waxless repulpable, recyclable and compostable moisture resistant corrugated paper poultry box intended for use in wet food processing conditions comprising a corrugated paper box having a composite structure with a fluted medium and liner sheets secured to each side of said fluted medium, said liner sheets and fluted medium being impregnated with a hydrogenated triglyceride vegetable oil, namely, palm oil and said liner sheet's outer surfaces are wet coated with an emulsified mixture of styrene acrylic copolymer based solution ranging from about 75% to about 95% by weight and hydrogenated triglyceride vegetable oil, namely, palm oil ranging from about 5% to about 25% by weight, in a range of about 1.0 to about 2.0lbs. weight per thousand square feet of liner surface, said coating imparting improved moisture resistance and wet strength to said corrugated paper poultry box.

21. A waxless repulpable recyclable moisture resistant poultry box comprising a corrugated paper composite structure with a paper fluted medium and paper liner sheets secured to each side of said fluted medium, said paper liner sheets and paper fluted medium being impregnated with palm oil ranging from about 2.5 to about 3.5 lbs/MSF with at least one of said paper liner sheet's outer surfaces being coated with an emulsion of about 80% styrene acrylic mixed in water by weight and about 20% palm oil by weight, said emulsion coating imparting improved moisture resistance and wet strength to said poultry box.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic of the process used in making the poultry box composite material;

(2) FIG. 2 is a top plan view of the inventive poultry box invention; and

(3) FIG. 3 is an enlarged cross sectional view of the inventive poultry box invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) The preferred embodiments and best mode of the invention are shown in FIGS. 1 through 3. 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.

DEFINITIONS

(5) As used herein the following abbreviations and terms are understood to have the meanings as set forth:

(6) Triglyceride includes both animal fats and vegetable oils and is derived from one or both of them. 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.

(7) Paraffin is a wax-like product derived from petroleum.

(8) Paper includes substrates and surfaces of cellulosic material.

(9) 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.

(10) 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.

(11) 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 an A flute having 33+/3 flutes per lineal foot with a flute thickness of inch or 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 adhered 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. 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.

(12) The present repulpable inventive degradable poultry box 10 is constructed with an inner Kraft paper liner or backer 12 impregnated with a hydrogenated triglyceride, preferably tallow at 2.5 lbs/MSF, a corrugated paper medium 14 impregnated with a hydrogenated triglyceride, preferably tallow at 3.5 lbs/MSF and the outer Kraft paper liner or backer 16 is impregnated with tallow at 2.5 lbs/MSF. Other triglycerides can be used such as animal fats and 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. Tallow used in the impregnation is commercially available from C.J. Robinson Co. and Chemol Corporation. After tallow impregnation of the paper liners, both liners or backers 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. 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 170 F.

(13) 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.

(14) The present poultry box 10 is constructed using standard corrugated box making machinery as is well known in the art. A roll of the medium paper 30 is positioned upstream of the corrugator. The paper is wetted and passed through a standard corrugating machine 35 and formed into a corrugated medium 32 having the desired flute size, preferably A or C. The corrugated medium 32 is transported downstream through a tallow bath 36 and rollers with the corrugated medium being impregnated with tallow at 2.5 to 3.5 lbs/MSF. The impregnated corrugated medium 37 is carried by belts to an assembly station 60 where the coated liner backers 45 and 55 as further described below are secured to the corrugated medium 37 to form a composite sheet poultry box carton blank. Two liner rolls of roll stock of Kraft paper 40 and 50 are removed from the respective rolls and the respective liner sheets 41 and 51 are transported by rollers through separate hydrogenated triglyceride, preferably tallow baths 42 and 52 and their associated rollers which applies tallow to the liner backer sheets 41 and 51 at 2.5 lbs/MSF impregnating the same. The now impregnated liner backer sheets 43 and 53 are then transported by rollers to and coated at coating stations 44 and 54 on a single sheet surface side with the emulsion coating 18 heated to about 170 F. The emulsion coating can be placed on the sheet backing surface by rollers, doctor blades or spraying as is well known in the art. The coating is translucent to milky white and is water based. The coated liner sheets 45 and 55 are then glued at gluing station 60 to the corrugated medium 37 with a suitable adhesive as is well known in the art to form a coated corrugated composite board with emulsified coating 18 on its top and bottom outside surfaces. The coated corrugated composite board 61 is then passed over a heat curing bed 70 to cure and set the adhesive or glue. The heat curing bed 70 is a series of hot plates and pressure rollers which applies light pressure and heat to cure the adhesive which is standard in the corrugated box making art and the glue cures very rapidly. The composite board is run through a chill plate assembly 80 which drops the corrugated temperature 70 F. allowing the blanks to be stacked without sticking. The composite corrugated board sheet 61 is then cut into individual blank sections in a cutting and stacking station 90 with known means stacking the individual flat sheets of composite corrugated board. If desired, air impact dryers 100 can be used to dry the flat sheets. 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 composite poultry box 10 in the form shown in FIG. 2.

(15) The poultry boxes are then delivered and assembled at the poultry packing plant and an adhesive provided by the manufacturer is placed vertically along the poultry box to provide a structurally sound moisture proof poultry box 10.

(16) 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: