US2999758A - Ice cream package - Google Patents

Description

Sept. 12, 1961 Filed May 1.9, 1958 PHP5/P 2 Sheets-Sheet 1 Sept. 12, 1961 Filed May 19, 1958 F. A. BROWN ICE CREAM PACKAGE 2 Sheets-Sheet 2 HOU/P5 fly-4 Hal/E5 2,999,758 `ICE CREAM PACKAGE Frank Alan Brown, Lake Zurich, Ill., assigner to N This invention relatesgenerally to packaging having y improved barrier characteristics and, more particularly, it relates to cartons which are intended for use in the packaging of ice creams, sherbets, and the like.

Foods having relatively high moisture content, particularly frozen foods such as ice creams, sherbets, vegetables, fruits and the like, are frequently marketed in wax coated paperboard containers. The wax coating is applied to the yinner surface of the paperboard container, so as to provide a moisture barrier and thereby lessen dehydration of the packaged product. Furthermore, such a barrier minimized -wetting of the paperboard which was believed necessary to provide a satisfactory carton. In addition, various paperboard containers also have wax coatings applied to their outer surface.

However, waxed paperboard containers have not been wholly satisfactory for use with frozen foods of high moisture content, such as ice creams, sherbets and the like, and deterioration of the product occurred after rather short periods of time. Such deterioration of the product limits its shelf life, and consequently, the product must be picked up often thereby increasing the cost of marketing. Furthermore, such relatively rapid deterioration requires prompt use by the purchaser of the product to prevent spoilage.

Furthermore, in order to avoid imparting undersirable iiavors and odors to the frozen product, the type and purity of the wax coating utilized on the frozen food container surfaces must be carefully controlled. When the product is removed from the waxed container, a portion of the wax may also be removed, and accordingly, careful control of the wax is also required for this additional reason.

There is further disadvantage to the use of waxed containers in that in the packaging operation, the wax on the surfaces often builds up on the packaging equipment and interferes with the packaging operation.

Moreover, when the outer surface of the container is waxed, the quality of printing and vividness of color is reduced thereby limiting the saleability of the product.

Various attempts have been made to avoid the disadvantages arising from the use of wax coatings on the surfaces of paperboard containers utilized for high moisture content foods. In this connection, unwaxed containers, in some cases, have been utilized. However, it has been found that, in general, when such containers are used, increased dehydration of the product occurs, and shelf life is accordingly reduced. Lesser amounts of wax have also been tried but satisfactory results have not been achieved.

l have now discovered a container having improved moisture resistance, which `is particularly suitable for frozen foods of high moisture content, such as ice creams, sherbets and the like. When the improved container of this invention is utilized, deterioration of the contained product is minimized and the shelf life of the product is extended. In addition, the containers of this invention can be more easily handled on packaging equipment. Certain of the containers disclosed herein can also be preprinted at a faster rate than can conventional waxed paperboard containers, and moreover, the printing reproduction is of improved quality. Furthermore, the containers of the present invention are easily fabricated and are relatively inexpensive to manufacture.

Accordingly, the primary object of this invention is to provide an improved carton for the packaging of ice creams, sherbets and the like.

Another object of this invention is to provide an improved carton of the type described which has controlled absorption characteristics but which maintains the initial quality of ice creams, sherbets and the like for extended periods. v

Still another object of the present invention is the provision of an improved food package for ice creams, sherbets and the like, the package having improved moisture impermeability qualities and an inner unwaxed paperboard surface which absorbs some moisture from the' packaged product.

It is a further object of this invention to provide an improved paperboard food carton of the type described, which can be more readily preprinted and handled on packaging equipment.

It is still another object of this invention to provide a carton which can be readily stripped from the contained product.

Further objects of this invention will be apparent from a study of the following detailed description, and the accompanying drawings, in which:

FIGURE l is an enlarged sectional View of a portion of a container constructed in accordance with the present invention;

FGURE 2 is also an enlarged sectional View of a portion of another container embodying features of the present invention;

FIGURES 3 and 4 are graphs showing moisture vapor transmission characteristics of paperboard sheets and of pint cartons made of various materials.

Both of the cartons ll and 13 illustrated in FIGURES l and 2, respectively, are intended for use in packaging ice creams, sherbets and the like, and are fabricated from a built-up board which comprises 4a sheet of paperboard which is unwaxed but may be otherwise treated, so long as it has moisture absorption characteristics. The paperboard sheet is laminated to a barrier material. The cartons l1 and 13, made from the built-up board, are formed so as to place the paperboard surface of the built-up board in contact With the ice cream, sherbet or the like. 0f course, the containers of this invention are of the usual shape and size, but any desired shape or size may be employed.

Referring now particularly to FIGURE l, the carton 11, shown therein, represents one form of the present invention and is fabricated from a built-up board v14 comprising several layers which are laminated together, the layers including a paperboard sheet l5, a wax barrier 17, and a coated printing paper 19.

The paperboard l5, which lines the inner surface of the iinished container adjacent the food product, is unwaxed and unsized so as to provide absorption of moisture, and is preferably a bleached paperboard of between about l0 and about 22 points thickness depending upon the size of container to be employed. However, the board should not be so thick that it absorbs a substantial amount of moisture from the contained food material. The paperboard may have a weight of between about 60 pounds per ream and about 250 pounds per ream. The paperboard may be made from any suitable stock, such as semi-chemical, chemical, or mechanical pulp but is desirably made from sulfate pulp. However, the paperboard may be suitably sized to assist imparting suicient strength to make the cartons self-supporting. The s-izing may be any of the usually employed agents for sizing conventional types of paperboard such as starch, glue, animal sizing, rcsin or the like. Of course, the sizing should be neutral in odor and taste so as not to impart any flavor to the contained product.

The wax barrier l? is disposed between the paperboard and paper, and accordingly, the wax barrier does not contact the frozen food` The wax barrier may be any suitable wax mixture which is non-penetrating, and non-bleeding at temperatures between about -Zfof F. and about 110 F. Natural or synthetic waxes, such as parain, candellila, chlorowax, various Irnicrocrystalliue waxes, etc. may be included in the mixture along with crepe rubber or other polymers. The wax component should readily adhere, when solidified, to the paperboard 15 and also to the paper =19. In addition, the wax should not be so brittle as to crack at the temperatures encountered (as low as about 20 E).

The wax barrier 17 may be coated in the uid state on the desired surface of the paperboard l5 by any conventional technique. -For example, the barrier may be applied by hot rolling, followed by chill rolling under pressure to solidify the wax on the paperboard 15, causing tight adherence of the wax to paperboard. The wax should not be pressed so strongly into the surface of the paperboard as to penetrate that layer.

The wax barrier is applied as a coating of thickness of at least about 0.5 point, and preferably of about 2 points. The wax barrier should be used in an amount of at least about l pounds per standard rearn of 3,000 square feet of paperboard, if the results of this invention are to be enjoyed. However, the amount should not exceed about 25 pounds per ream so as to not impair the handleability of the built-up board 14.

To the exposed surface of the wax barrier may then be applied a high grade of smooth surfaced paper, preferably supercalendered bleached sulite paper. The paper may be coated with a thin layer of moisture resistant lacquer, shellac, varnish or other suitable substance. The paper 19 will be greater than about 0.5 point in thickness, preferably about 3 points, and preferably has a basis weight of from about 30E pounds to about 40 pounds per ream of 3,000 square feet of paper.

The laminated board of the invention may, of course, be assembled in a number of Ways. For example, the smooth surfaced paper 19 may be applied after the wax barrier has solidiiied on the paperboard 1S. Alternatively, the paper 19 may be applied to the exposed surface of the wax barrier while the latter is still in a softened or molten state, i.e. immediately after or duringV application of the wax barrier to the paperboard 15.

The combined thickness of the wax barrier and the paper sheet in the built-up board may be as little as about l point and is preferably about 5 points. The paperboard, as indicated above, may be from l() to 22 points in thickness, and accordingly, the total thickness of the built-up paperboard may be as high as 27 points.

The built-up board 5 may be printed after fabrication, or the paper may be reprinted. Such preprinting permits high speed operation and can be effected at Speeds greatly in excess of the time required for printing the built-up board. In addition, the use of high grade paper permits highly satisfactory reproduction, particularly with color printing. As a result, a more attractive package is provided.

The carton 13 illustrated in FIGURE 2, represents another form of the present invention, and is fabricated from a built-up board Z1 which includes an inner paperboard layer 23 and an outer foil layer 25' bonded to the paperboard 23. The inner paperboard layer is of a paperboard similar to the paperboard 15 employed in the carton 11 and is substantially unsized and otherwise particulariy water-proofed or made Water repellent.

The foil layer ZS may be of tin or aluminum or the like, which is substantially free of pin holes or fissures. In the illustrated embodiment, the foil layer comprises a tissue backed foil which isv bonded to the paperboard by the use of an adhesive, which is non-penetrating and non-bleeding within the temperature range of about 20 F. to about 110 F. ff desired, the foil may be The following examples more particularly set forth certain aspects of the present invention.

Example I A bleached, unwaxed kraft paperboard, sized with corn starch, 1l points in thickness and weighing about 180 pounds per ream, was coated on one side with a parain wax-crepe rubber mixture at a temperature of about F. at which temperature the mixture flowed. The amount of wax-rubber mixture utilized was about 16 pounds of wax per ream of paperboard. (This wax coating had a thickness of about Z points on the paperboard.) The wax-rubber mixture was applied to one surface of the paperboard by means of an application roll and a doctor roll. To the exposed wax-rubber surface was immediately applied (while the wax was sti-il soft) a supercalendercd, white suliite paper sheet of about 3 points in thickness and weighing about 31.5 pounds per ream. The wax-rubber mixture did not substantially penetrate the paper or board. The surface ofl the paper sheet applied to the mixture was uncoated, lwhile the opposite exposed surface of the paper sheet had coating and printing thereon. The paperv was printed prior to application to the paperboard at the rate of about 120() feet per minute on high speed presses. The colors were vivid and outstanding compared to the usual carton in the ice cream carton field.

Rolling of the board construction (which at this stage comprised the kraft paperboard, the wax coating and the paper sheet) between pressure rolls eifectively sealed the paper sheet to the paperboard, by means of the wax.

The printed built-up board was then formed into pint ice cream cartons. The ice cream cartons were 'lled with ice cream at a maximum filling rate of 60 per minute. Representative lled cartons were then tested.

Because the cartons hadA no exposed wax coated surfaces, no difficulty was experienced in the iilling machine over extended periods of operation due to the buildupof wax.

in order to compare the board of this invention with the usual ice cream carton board, kraft paperboard, as above described, was printed at the maximum rate of 50() feet per minute, and was coated on both sides with paraffin wax. rThe wax coating was applied by immersion in molten paraffin, followed byy .rolling between pressure rolls. The total amount of paraffin wax utilized for coating both sides was about 5 pounds per ream of paperboard. The waxed paperboard was then shaped into pint Iice cream cartons. The cartons were filled with ice cream. Representative illed cartons were then tested.

It was found that notv only was the printing of the cartons of this invention at a higher rate than the rate of printing of conventional ice cream cartons (1,200 feet per minute as compared' with about 500 feet per minute), but the quality of printing reproduction was noticeably improved on the cartons of the invention. The printing reproduction on the conventional wax coated cartons was considerably less vivid and lacked deiinition as compared to the printing reproduction on the uncoat'ed cartons of the invention. During the test, a build-up of dried mix (dehydrated ice cream) was noted on the surface of the wax coated cartons over a period of time. No such ganarse build-up was found on the cartons of the invention, indicating limited absorption of moisture from the ice cream, contrary to expectations.

When the cartons of the invention were stripped Yof ice cream, the ice cream was noticeably easier to remove from these cartons. This characteristic is called break-away. In this connection, cartons of the invention showed much better break-away than the wax coated cartons. Moreover, when both types of cartons were stripped of ice cream and left exposed to the ai-r at room temperature (65 F.) for a few minutes (5 minutes), the surface cling of ice cream on the cartons of the invention melted rapidly, whereas the surface cling on the wax coated cartons softened only slightly and was removable from the carton surface only by scraping. Analysis of the scrapings by taste and usual observation indicated that the scrapings comprised dehydrated ice cream, together with a small amount of paraffin wax, in the case of the wax coated cartons.

The improved performance of the containers of this invention over containers of conventional construction is demonstrated by the above example. A high preprinting rate, less difficulty in filiing, better printing reproduction, a higher degree of break-away and decreased clinging occur when the containers of the present invention are utilized instead of conventional containers. Wholly unexpectedly, the containers of the present invention exhibit decreased dehydration of the frozen, high moisture content product over conventional waxed cartons, despite the presence of unwaxed paperboard surfaces in direct contact with the frozen food.

Example Il The moisture vapor transmission of finished paperboard sheet of the present invention was compared with that of two conventional paperboards regularly utilized for the construction of ice cream containers.

The built-up paperboard of the present invention was prepared in the manner set forth in Exampie I, and accordingly, comprised a 16 point finished paperboard sheet having an 11 point paperboard inner layer, a 2 point intermediate layer of wax-rubber and a 3 point outer layer of white sulfite paper. However, the iinished paperboard sheet was not printed. The board is designated 1 in FIGURES 3 and 4 of the drawings.

A conventional paperboard used commercially for packaging ice cream and having a thickness of approximately 16 points was obtained for testing. The board included a coating of wax on each side. The paperboard was not printed. This board is designated 2 in FIGURES 3 and 4 of the drawings.

Another paperboard, also used commercially for ice cream, was obtained from a different manufacturer. This board had a thickness of 16 points and was coated on both surfaces. The paperboard also was not printed. The board is designated Si` in FIGURES 3 and 4 of the drawings.

The moisture vapor transmission test was conducted in the following manner:

A moisture-proof cup having a closed bottom and an open top of 4.9 centimeter diameter was filled with a commercial desiccant, anhydrous calcium chloride. A sample of the paperboard sheet to be tested was sealed across the top of the cup. The adjoining sur-faces of the paperboard sheet and the lip of the cup were sealed. T he desiccant lied cup with the paperboard sheet sealed in place was weighed and then placed 4in a chamber to which was introduced high moisture content air. The humidity reading for the introduced air was maintained at 90% during the course of the test, with 100 F. dry bulb and 97 F. wet bulb readings. Each test was run for a period of 168 hours. At regular intervals during the test period, the amount of water vapor absorbed by the desiccant was determined by weighing the iilled cup with the paperboard sheet in place,

The above test was run on the three types of paper'- board above described. Runs were made on three samples of each of the three paperboard sheets. In the case of the paperboard of the present invention, the paperboard wasplaced on the cup so that paperboard 7 faced the interior of the cup. Since both the paperboard sheets 2 and 3 were paperboard constructions having both surfaces identical, no distinction was made between the two sides, either side of the paperboard sheet being placed to face the interior of the cup.

The results obtained were averaged for the three samples of each type of paperboard, and plotted graphically, the grams increase in moisture in the desiccant per hundred square inches of paperboard sheet exposed to the high humidity air being plotted against the tt time in hours. The graph obtained is set forth in FIGURE 3 of the accompanying drawings.

Referring now more particularly to FIGURE 3, it is seen that the increase in the moisture content ofthe desiccant is substantially a straight line function with time for each of the paperboard sheets. That is the moisture vapor transmission rate for the paperboard sheets 1, 2 and 3 remained substantially constant over the total test eriod. However, there was a marked difference between the moisture vapor transmission rate of the paperboard sheet of the present invention, as indicated by line 1, and that of the commercial sheets as indicated by lines 2 and 3. Thus, over a period of 168 hours, the total amount of moisture picked up by the desiccant when the paperboard sheet of the present invention was utilized was approximately 6 grams per hundred square inches of paperboard exposed to the high humidity air. In contrast, paperboard 2, at the end of 168 hours, had allowed approximately 400 grams of moisture vapor to pass through it per hundred square inches of exposed surface. Paperboard 3 had allowed approximately 335 grams of moisture vapor to pass through it per hundred square inches of paperboard.

The results graphically illustrated in FIGURE 3 clearly demonstrate the marked improvement in moisture resistance afforded by the finished paperboard of the present invention. Such an improved moisture resistance appreciably affects the quality of high moisture content foods enclosed in a container prepared from such paperboard. For example, as indicated in Example I, the amount of dehydration and clinging of the food to the surfaces of the paperboard is substantially decreased over the results obtained with commercial 'paperboards Example III Another series of tests was performed to determine the moisture vapor transmission -rate of paperboards 1, 2 and 3 when the paperboards were fabricated into conventionally shaped pint volume ice cream cartons. The cartons made from paperboard 3 had yan average weight oi' 48.6 pounds per 1000 pint cartons, from paperboard 2, 51.6 pounds per 1000 cartons and from paperboard l, of the present invention, 52.6 pounds per 1000 cartons. One sample of each of the three types of cartons was tested. The test, in each case, was performed in the following manner:

into the pint carton to be tested was introduced sufficient anhydrous calcium chloride, a desiccant, to ll the carton. The cover flaps of the carton were then folded over into sealing position and the carton was then weighed. The desiccant-lled carton was introduced into a chamber and held for a period of time in the presence of high humidity air, as in the tests of Example II, that is, at humidity, with readings on the wet bulb of 97 F. and on the dry bulb of 100 F.

In the case of carton fabricated from paperboard 2, the test was discontinued vafter 72 hours. In the case of carton fabricated from paperboard 3, the test was discontinued after 48 hours. The carton fabricated from the paperboard sheet of the present invention was tested for a tata! af. 16 heals.

At intervals during the test period, the carton containing the desiccant was weighed to determine the amount of water picked up by the desiccant. The results were plotted graphically, with the total number of grams of moisture vapor absorbed by the desicoant being plotted against the test time in hours. The graph obtained is as set forth in FIGURE 4 of the accompanying drawings.

Referring now more particularly to FIGURE 4, it is seen that, as in FIGURE 3, the rate of moisture vapor transmission for each of the three types of paperboard cartons remained substantially constant over the period tested. However, a great diierence existed with respect to the rates of moisture vapor transmission. Thus, over a period of 168 hours of exposure to the high humidity conditions, the carton fabricated from the paperboard of the present invention allowed, as indicated by line 1,

a total moisture vapor transmission of approximately 14 In contrast thereto, the carton fabricated from paperboard 2 showed a total moisture vapor transmission of approximately 92 grams after exposure to the saturated moisture vapor conditions for a peri-od of 72 hours, after which the test was discontinued-` The results obtained with the carton fabricated from paperboard 3 were even less satisfactory in that after a period of only 48 hours of exposure to the high humidity conditions, the container was found to have allowed a ltotal moisture vapor transmission of approximately 91 grams. The improved moisture resistance of cartons fabricated from the paperboard of the present invention is clearly demonstrated.

Example IV A solid bleached, 14 points sulfate board, which was substantially unsized and unwaxed or otherwise specially treated to obtain moisture impervious qualities, was bonded by the use of a usual adhesive to a tissue backed foil having a thickness of .00035 inch to form a laminated board of approximately 141/2 points in thickness. A vcarton blank was cut from this laminated board and set up into a one pint ice cream container with the uncoated paperboard comprising the inner surface of the container.

The erected carton was then filled with ice cream and was then placed on a three-hole chest type freezer and maintained at an average temperature of F. for a period in excess of one year.

By way of contrast, ice cream was packaged in a conventional carton of 16 point, solid bleached suliite board which was wax coated on both sides in an amount of 11/2 pound per ream per side. The waxed board had a total caliper of 171/2 points. The construction of this carton was the same as that of the laminated package above described.

The carton was then filled with ice cream and was stored in a hardening room at approximately 20 F.

for a period just over nine months.

Each of the cartons under test was opened at the same time for comparative evaluation. It was found that the ice cream in the laminated carton was still saleable after storage for over one year and that no substantial deterioration of the ice cream had taken place. In addition, the ice cream was readily stripped from the board. By contrast, the ice cream the conventional carton was unsaleable, dehydrated, and whoily unsatisfactory.

Accordingly, it seems obvious that the use of the carton of the invention was completely satisfactory as compared to the unsatisfactory result obtained by use of the conventional wax coated carton. In particular, the storage characteristics of the laminated carton far exceeded those of the conventional carton.

The concept disclosed herein relating to the packaging of ice creams, sherbets and the like in a carton constructed from a laminated board having limited ab sorption characteristics so lthat the inner paperboard surface in contact with the product picks up some moisture, and a moisture repellent barrier bonded to the outer surface of the paperboard, is believed to be new and provides highly desirable results with ice creams, sherbets and the like. The co-action between the product and the board is not wholly understood.

The cartons and packages described above have been disclosed in connection with the packaging and marketing of ice creams, sherbets, and the like. However, for

purposes of convenience, the term ice cream, as used herein, includes ice creams, sherbets and like products which are in the fluid state when iilled in a carton, and which are subsequently hardened.

Various modiiications in the construction of the frozen food package and in the carton of the present invention, in the method of manufacture and in the equipme-nt for carrying out the same as are within the skill of those versed in the ait are contemplated as being within the scope of this invention.

I claim:

l. An improved ice cream package comprising ice cream contained in a self supporting carton, said carton being fabricated from a built-up board includ-ing paperboard having moisture absorption characteristics, and a moisture repellent barrier bonded to one side of said paperboard, the paperboard side of said buiit-up board forming the inner moisture-absorbing surface of said carton and being in Contact with and absorbing moisture from said ice cream said paperboard being at least about 10 points in thickness.

2. An improved food package comprising ice cream contained in a self supporting carton, said carton being fabricated from a laminated board including a layer of bleached paperboard having moisture absorption characteristics and a-highly moisture impervious foil layer bonded to one side of said paperboard, said paperboard being between about 10 and about 22 points in thickness and being for contacting and absorbing moisture from said ice cream, said carton being fabricated with the paperboard side of said iarninated board `forming the inner moisture-absorbing surface of said carton.

3. An improved food package comprising ice cream contained in a self supporting carton, said carton being fabricated from a multi-ply board including a bleached paperboard ply having `moisture absorption characteristics, a ply of paper, and a moisture impervious barrier bonded between said paperboard ply and said paper ply, said paperboard being between about 10 and about 22 points in thickness, said carton being fabricated from said multiply board with the paperboard side thereof forming the inner moisture-absorbing surface of said carton and being in contact with and absorbing moisture from sm'd ice cream.

References Cited in the file of this patent UNITED STATES PATENTS 1,693,841 Gaylord Dec. 4, 1928 1,936,375 Beecher Nov. 21, 1933 2,048,123 Howard July 21, 1936 2,098,223 Balnhart Nov. 9, 1937 2,171,775 Wilshire Sept. 5, 1939 2,184,166 Rape Dec. 19, 1939 2,415,387 Graebner et al. Feb. 4, 1947 2,714,952 Ireton Aug. 9, 1955 2,828,240 Couch et al. Mar. 25, 1958 OTHER REFERENCES Refrigerating Engineering, February 1954, pp. 45-48.

Claims (1)

1. AN IMPROVED ICE CREAM PACKAGE COMPRISING ICE CREAM CONTAINED IN A SELF SUPPORTING CARTON, SAID CARTON BEING FABRICATED FROM A BUILT-UP BOARD INCLUDING PAPERBOARD HAVING MOISTURE ADSORPTION CHARACTERISTICS, AND A MOIST REPELLENT BARRIER BOUNDED TO ONE SIDE OF SAID PAPERBOARD, THE PAPERBOARD SIDE OF SAID BUILT-UP BOARD FORMING THE INNER MOISTURE-ABSORBING SURFACE OF SAID CARTON AND BEING IN CONTACT WITH AND ABSORBING MOISTURE FROM SAID ICE CREAM SAID PAPERBOARD BEING AT LEAST ABOUT 10 POINTS IN THICKNESS.

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