US3366496A - Food packaging process - Google Patents

Description

T. C. BOMAR ETAL FOOD PACKAGING PROCESS Jan. 30, 1968 5 Sheets-Sheet 1 Filed July, 29, 1965 INVENTOR. 77/0/7/15 6. HUGH/3 50/44? .70/9/1/60/1/ W/L L /A M 5. MC 00444.40

Jan. 30, 1968 T. c. BOMAR ETAL 3,366,496

FOOD PACKAGING PROCES S 5 Sheets-Sheet 2 Filed July 29, 1965 FIG.5

INVENTOR. 7/70/7145 6' 50/7/09 HUGH B. JOHNSON WILL /AM 5 Mc DON/1L0 5) v Jan. 30, 1968 T. c. BOMAR ETAL 3,366,496 FOOD PACKAGING PROCESS Filed July 29, 1965 3' Sheets-$het s 1FOIG.IO

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INVENTOR. 7/9 0/1/15 a emu/P HUG 1 8. JOH/VJO/V WILL/AM 5. NC 004 4410 ATTO/PA/E) United States Patent 3,366,496 FOOD PACKAGING PROCESS Thomas C. Bornar, Wiiliarn S. McDonald, and Hugh B.

Johnson, Georgetown, S.C., assignors to International Paper Company, New York, N.Y., a corporation of New York Filed July 29, 1965, Ser. No. 475,786 4 Ciaims. (Cl. 99-198) This invention relates to containers and, more particularly, to containers made of corrugated paperboard for packaging perishable foods, such as fruits or vegetables.

Fruits, such as peaches, are picked in the summer and it is necessary to cool them as quickly as possible to remove field heat and to prevent spoilage. A known method for accomplishing this is hydrocooling; that is, cooling by use of water.

The present invention is of particular significance in the packaging of perishable foods which have been hydrocooled prior to storage and shipment.

In one form of hydrocooling employed in the peach industry, the peaches are packed, in bulk, in open-top containers and subjected to a cold water shower. The water circulates around the peaches to cool them and drains through openings in the containers and into a water collection trough where it is recirculated back into the cooling system. After the peaches are cooled sufiiciently, the tops are placed on the containers, which are stacked one atop the other on pallets and placed in high humidity refrigeration rooms to await shipment.

Since moisture is known to adversely affect the strength of corrugated paperboard, it has been the general practice to use wooden containers or wood-wirebound crates in packaging peaches under the conditions just described, in spite of their expense and attendant dimculties in handling.

It is, therefore, a principal object of this invention to provide a container formed of corrugated paperboard which is capable of use in the packaging of perishable foods under moist or humid conditions.

It has been found that particular attention must be paid to the choice of components (liners and medium) which are to comprise the corrugated paperboard of the present invention and to the method of making such corrugated paperboard.

Preferably, the liners are formed from wet-strength linerboard, available commercially under the trademarks Hydro Kraft and Gator Pak, owned by International Paper Company, and the corrugating medium is formed from wet-strength paperboard, available commercially under the trademarks Hydro-Chem and Weathertex, also owned by International Paper Company.

A preferred method of making the corrugated paperboard of this invention includes the steps of treating the corrugating medium with wax or a wax blend prior to corrugating, and treating the liners with wax or a wax blend either prior or subsequent to the securing of the liners to the corrugated medium.

The wax or wax blend used to treat the liners should be of a refined quality suitable for use in contact with foods and it is applied with particular regard respecting its temperature and point of application so as to obtain liners capable of use in the packaging of foods under Wet, moist, or humid conditions.

The corrugating medium is treated with wax or a molten blend of waxes and thermoplastic resins or thermoplastic resins alone prior to corrugating, using critical temperatures and moisture treatment or treatments so as to obtain a corrugated medium capable of use in the packaging of foods under wet, moist, or humid conditions.

The container blanks of the present invention may be formed from the corrugated paperboard of the invention by well-known means and with standard equipment.

3,3hh,4% Patented Jan. 30, 1968 It is preferred that the flutes of the corrugated medium in the blanks and in the containers formed from the blanks should be disposed predominantly longitudinally of the blanks to assure that the minimum number of flute openings will be disposed to accept debilitating water.

More specifically, the containers of this invention are comprised of a body and a cover which can readily be secured or locked to the body as a final step of a method of packaging perishable foods which have been hydrocooled in the body. The containers are provided with reinforced parts to give them stacking strength, simple fastening means by which they are secured erect, eflicient and non-contaminating drainage means, and locking means to lock the cover to the body.

A further object of this invention is to provide a corrugated paperboard container having excellent drainage and good stacking strength.

A further object is to provide a corrugated paperboard container capable of withstanding a cold water shower and the rigors of storage and shipment.

Another further object is to provide a container formed of corrugated paperboard having high resistance to water.

Another object is to provide a container which is formed from a fiat one-piece blank which is simple in construction and economical to manufacture.

Another object is to provide a corrugated paperboard container in which a minimum number of flute openings are disposed to accept debilitating water.

And, another object is to provide a container cover formed of corrugated paperboard and having a high resistance to water.

Other objects and advantages Will become apparent from the following specification, claims, and drawings, in which:

FIG. 1 is a plan view of a blank from which a container body of the present invention is made;

FIG. 2 is a plan View of a blank from which a container cover of the present invention is made;

FIG. 3 is a perspective view (with parts broken away) showing a stage of folding the blank of FIG. 1;

FIG. 4 is a perspective view (with parts broken away) showing a stage of folding the blank of FIG. 1;

FIG. 5 is a perspective view (with parts broken away) showing a stage of folding the blank of FIG. 1;

FIG. 6 is a perspective view (with parts broken away) showing a stage of folding the blank of FIG. 1;

FIG. 7 is a perspective view (with parts broken away) showing a stage of folding the blank of FIG. 1;

FIG. 8 is an exploded perspective view showing the assembled container cover and container body;

FIG. 9 is a sectional view taken along line 9-9 of FIG. 8; and,

FIG. 10 is a sectional view taken along line 1010 of FIG. 8.

The container 106, as seen in FIGS. 8, 9, and 10, comprises a body B formed from a blank 1 (FIG. 1), and a cover C, formed from a blank 30 (FIG. 2).

Theblanks 1 and 30 are formed from corrugated paperboard which consists of acorrugated medium 101 sandwiched between an inner liner 102 and outer liner 163. The orientation of the flutes of thecorrugated medium 101 is predominately longitudinal of the blank, for reasons to be further explained.

The blank 1 for forming the body B has horizontal fold lines 2,vertical fold lines 3, andslots 4 which define and hingedly connect a bottom 5 (including first andsecond bottom panels 6 and 7), side walls 8 (including first and secondside wall panels 9 and 10), end walls 11 (including first, second and thirdend wall panels 12, 13, and 14), and an attaching flap 15 for forming a manufacturers joint when forming the blank into a container body.

The bottom panels, the side wall panels, and the end wall panels are provided with means definingwater drainage openings 16, in the form of elongated cut-outs 17, in the form of circular cut-outs 18, and in the form of semicircular cut-outs 19. The first and secondend wall panels 12 and 13 are each further provided with means defining a hand-hold 20, in the form of an elongated cut-out 21, and with means defining acover locking aperture 22, in the form of anelongated cutout 23 and the horizontal fold lines 2a and 2b define stackingledge panels 24 therebetween, all for purposes to be described.

The blank 30 for forming the cover C has horizontal fold lines 31,vertical fold lines 32, andslots 34 which define and hingedly connect atop panel 35,side walls 36, and end walls 37 (including first, second, and thirdend wall panels 38, 39, and 40).

The blank 30 is further provided with means defining a pluraltiy of connectingflaps 41, in the form ofarcuate slits 42 extending substantially from intersections of the horizontal andvertical fold lines 31 and 32, and each of such connecting flaps is provided with means defining acover locking aperture 43, in the form of a substantially rectangular cut-out 45. The thirdend wall panels 40 are each cut away, as at 46, to definecover locking tabs 47 and abody locking tab 48; thetop panel 35 is provided with means defining a water drainage opening 49, in the form of a circular cut-out 50, and the fold lines 32a define a hand-hold ledge 51 therebetween, all for purposes to be described. 1

To form the body B from the blank 1 of FIG. 1, theside panels 9 and theend panels 12 are folded perpendicularly to each other and to the attaching flap 15 which is folded into abutting contact with one of theend panels 12 where it is secured by glue or staples to form a manufacturers joint. Thebottom panel 6 is folded into temporary contact with one of theside panels 9 and theend panels 13 are folded into abutting contact with the bottom panel 7 and together these parts are folded perpendicularly to theother side panel 9, after which theend panels 13 are folded into abutting contact with theend panels 12 and thebottom panel 6 is folded into abutting contact with the bottom panel 7. The side panels and theend panels 14 are then folded into abutting contact with theside panels 9 and theend panels 13, respectively. Friction holds the parts, thus folded, in their respective positions.

To form the cover C from the blank 30 of FIG. 2, theside wall panels 36 are folded perpendicularly to thetop panel 35 and the secondend wall panels 39 are folded perpendicularly to thepanels 36 thus bringing the connecting flaps into abutting contact with the lower surface of thetop panel 35 at the four corners thereof. The first and thirdend wall panels 38 and 40 are folded perpendicularly to thetop panel 35 and around the secondend wall panels 39 and thecover locking tabs 47 are inserted in thecover locking apertures 43 in connectingflaps 41 to lock the parts in place, as shown most clearly in FIG. 8.

In the hydrocoolirig method of this invention, freshly picked peaches are packed, in bulk, within the body B and subjected to a cold water shower. The water drains through the matedwater drainage openings 16 in the bottom, side, and end wall panels and into a collection trough to be recirculated back into the cooling system. The cover C is then positioned on and secured to the body B by inserting thebody locking tabs 48 into thecover locking apertures 22, as shown in FIG. 9.

It will be noted that the flute openings of the corrugated paperboard of the cover C and the body B of the container are minimally exposed to debilitating water to further enhance the containers utility in the hydrocooling operation.

It is also important to observe that, aside from the single drainage opening 49, thetop panel 35 of the cover C has no water access openings in it. This is so in spite of the fact that the cover is capable of assembly without the use of extraneous means. Such assembly is accomplished by simply inserting the lockingtabs 47 into the lockingaperture 43 in the connectingflaps 41, which are positioned below and in abutting contact with the undersurface of thetop panel 35 at its four corners, thereby obviating the necessity of forming such apertures in the top panel itself at the corners thereof, as is commonly done.

It will be noted that the end walls 11 of container are of triple thickness; that theside walls 8 are of double thickness; and, that the bottom 5 is of double thickness. The thicknesses of the end and side walls give the container considerable stacking strength and the thicknesses of the bottom help retard heat pick-up after cooling.

It is further important to observe that the plurality of thicknesses of the end and side walls and the bottom provide a container of exceptional strength and it is within the scope of this invention to provide for the elimination of allopenings 16 in the end and side walls and in the bottom and for the elimination of the opening 49 in thetop panel 35 of the cover C and to thereby provide a container of exceptional strength for packaging articles in a dry state.

To lift the container, the user need merely to insert his fingers in the hand-holes 20 in the first and secondend wall panels 12 and 13 and lift it, in a manner well known in the art. Since there are no hand-holes in the thirdend wall panels 14, the users fingers do not contact the fruit inside the container; thus bruising is eliminated.

As has been previously stated, the specific corrugated paperboard used in the container and the method of making such paperboard are of paramount importance in the practice of the invention. Specifically, the paperboard must be capable of use in an environment of severe atmospheric conditions of wetness and humidity, which normally would tend to deteriorate the paperboard.

A preferred method of making the corrugated papera board of this invention comprises the steps of (1) treating the corrugating medium with wax or a wax blend prior to corrugating, (2) corrugating the treated medium, (3) securing the corrugated medium to inner and outer liners, and (4) treating the liners with wax or a wax blend. 7

In accordance with this invention, the material used in the container is preferably wet-strength paperboard. If desired, the paperboard may be treated by adding wet strength resins to the paper pulp at the heater and before the paperboard sheet is formed on the paper machine.

The corrugating medium is treated with wax or a wax blend, further to be described, preferably in molten form and ordinarily in an amount approximating 25 to 30% of the weight of the paper.

The corrugating medium is moisture conditioned by subjecting it to a water mist or spray prior to applying the wax blend by immersion or otherwise.

The treated medium is immediately thereafter subjected to further moisture and temperature conditioning by means of water mists, heaters, and steam applicators, all prior to being fed to the corrugating rolls.

Moisture and temperature conditioning are vital to the treatment of the corrugating medium. It has been found that these treatments enlarge the interstices of the sheet making it more receptive to the proper adhesion penetration necessary for adequate bonding. Further, an optimum moisture content improves the forming characteristic of the medium thereby minimizing the types of malformation possible during corrugating, and it also permits the use of conventional water system adhesives.

The paperboard is then corrugated by means of a set of corrugating rolls. During this operation, it is advisable to have the corrugating medium at a relatively high temperature.

After the corrugating operation is completed, a suitable adhesive is applied to the crests of the corrugations of the corrugated medium and one of the liners is pressed against the medium at the single-facer and held in place until it is secured thereto. Adhesive is then applied to the crests of the corrugations on the other side of the medium and the other liner is combined to it at the double-facer or double-backer.

The combined double-faced corrugated board then passes through the corrugator. The process has the advantage of being able to impregnate the medium and liners separately and with different formulations, blends, and quantities.

The invention may be employed on corrugating lines running at normal production rates of about 175 to 300 or 400 feet per minute. The standard weights of webs may be used but it is preferred to use 26, 30, 33 or 36 pounds per 1000 square feet (before corrugation) for the corrugated medium and 26, 33, 38, 42, 47, 69 or 90 pounds per 1000 square feet for the liners.

It has been found that the performance of the corrugated paperboard can be further improved by surface coating, preferably with hot melt wax blends. This is, of course, desirable in applications Where external water is the primary hazard, such as in hydrocooling operations. The board is preferably printed prior to the surface coating operation.

It is preferred to wax the liners at one or more waxing stations after the belt. Typically, the first station consists of two driven and heated rolls and the second station of two driven rubber rolls. The advantage of positioning the rolls past the belt is that by so doing the belt is not exposed to wax and, therefore, there is no danger of wax build-up.

The combined board is subjected to the wax showers beyond the corrugator belt, thus avoiding wax build-up on the belt.

The wax blend is applied in amounts approximating to 40% of the weight of the paper, and is heated from 225 F. to 300 F. depending on board grade and type and applied by rollers to the board. A wicking action occurs.

The wax blend which is employed preferably consists of a blend of waxes and petroleum resin polymers and copolymers with the wax totaling from 60% to 95% of the mixture. Approximately to addition based on the weight of the paper gives the best results. Beyond 30% the synergistic effect appears to diminish and the performance gained is not commensurate to the added cost.

The adhesive mixture which is employed is preferably of the aqueous type, starch or starch-resin combination.

The preferred method of applying the wax blend is inline on the corrugator thereby taking advantage of the heat generated by the corrugator. Wax continues to migrate during and after bonding due to the heat of the corrugator.

What is claimed is:

1. In the manufacture of corrugated paperboard consisting of a corrugated medium sandwiched between an inner and an outer liner and adapted to be converted into packaging, a process comprising the step of applying wax or a blend of wax and thermoplastic resin to the corrugating medium prior to corrugating, the step of corrugating the corrugating medium, the step of applying an adhesive formulation between the liners and the corrugated medium, and the step of bonding the liners and corrugated medium together with heat and pressure, wherein the corrugating medium is moisture conditioned before and after the wax or blend of wax and thermoplastic resin is applied to it.

2. A packaging process for packaging perishable foods in a container, said container being formed of corrugated paperboard consisting of a corrugated medium sandwiched between an inner and an outer liner and made in accordance with the process of claim 1, said container having parts including a bottom, side walls, and end walls and means defining water drainage openings therein, said packaging process including packing said foods in bulk within the container, subjecting the foods positioned within the container to a cold water shower, allowing the water to drain through the openings in the container body.

3. In the manufacture of corrugated paperboard consisting of a corrugated medium sandwiched between an inner and outer liner adapted to be converted into packaging, and a process comprising the step of applying wax or a blend of Wax and thermoplastic resin to the corrugating medium prior to corrugating, the step of corrugating the corrugating medium, the step of applying an adhesive formulation between the liners and the corrugated medium, the step of bonding the liners and corrugating medium together with heat and pressure, and the step of applying wax or a blend of wax and thermoplastic resin to at least one of the liners, wherein the corrugating medium is moisture conditioned before and after the wax or blend of wax and thermoplastic resin is applied to it.

4. In the manufacture of corrugated paperboard consisting of a corrugated medium sandwiched between an inner and outer liner adapted to be converted into packaging, a process comprising the step of applying wax or a blend of wax and thermoplastic resin to the corrugating medium prior to corrugating, the step of corrugating the corrugating medium, the step of applying wax or a blend of wax and thermoplastic resin to at least one of the liners, the step of applying an adhesive formulation between the liners and the corrugated medium, and the step of bonding the liners and corrugating medium together with heat and pressure, wherein the corrugating medium is moisture conditioned before and after the wax or blend of wax and thermoplastic resin is applied to it.

References Cited UNITED STATES PATENTS 1,592,824 7/1926 Fairchild. 1,856,282 5/1932 Holy 22934 2,099,936 11/ 1937 Kieckhefer. 2,418,963 4/ 1947 Anderson 22937 2,809,775 10/1957 White 22934 2,828,240 3/ 1958 Couch et al. 2,912,152 11/1959 White. 2,939,624 6/1960 Wilson 22934 X JOSEPH R. LECLAIR, Primary Examiner. GEORGE O. RALSTON, Examiner.

UNITED STATES PATENT OFFICE Certificate Patent No. 3,366,496 Patented January 30, 1968 Thomas C. Bomar, William S. McDonald, and Hugh B. Johnson Application having been made b Thomas C. Bomar, William S. McDonald, and Hugh B. Johnson, the inventors name in the patent above identified, and International Paper Company, New York, N.Y., a corporation of New York, the assignee, for the issuance of a certificate under the provisions ofTitle 35, Section 256, of the United States Code, deleting the name of Thomas C. Bomar as a joint inventor, and a showing and proof of facts satisfying the requirements of the said section having been submitted, it is this 18th day of December 1973, certified that the name of said Thomas C. Bomar is hereby deleted from the said patent as a joint inventor with the said William S. Mc- Donald and Hugh B. Johnson.

FRED W. SHERLING Associate Solicitor.

Claims (1)

1. IN THE MANUFACTURE OF CORRUGATED PAPERBOARD CONSISTING OF A CORRUGATED MEDIUM SANDWICHED BETWEEN AN INNER AND AN OUTER LINER AND ADAPTED TO BE CONVERTED INTO PACKAGING, A PROCESS COMPRISING THE STEP OF APPLYING WAX OR A BLEND OF WAX AND THERMOPLASTIC RESIN TO THE CORRUGATING MEDIUM PRIOR TO CORRUGATING, THE STEP OF CORRUGATING THE CORRUGATING MEDIUM, THE STEP OF APPLYING AN ADHESIVE FORMULATION BETWEEN THE LINERS AND THE CORRUGATED MEDIUM, AND THE STEP OF BONDING THE LINERS AND CORRUGATED MEDIUM TOGETHER WITH HEAT AND PRESSURE, WHEREIN THE CORRUGATING MEDIUM IS MOISTURE CONDITIONED BEFORE AND AFTER THE WAX OR BLEND OF WAX AND THERMOPLASTIC RESIN IS APPLIED TO IT.

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