US2441477A - Food package - Google Patents

Description

May 11, 1948. R. A. FARREm..

FOOD PACKAGE Filed Jan. 15, 1945 Patented May 11, 1948 FOOD PACKAGE Robert A. Farrell, Menasha, Wis., assigner to Marathon Corporation, Rothschild, Wis., a corporation of Wisconsin Application January 15, 1945, Serial No. 572,844

This invention relates to packages and containers for foods and other materials having a high moisture content. More specifically, this invention relates to packages having presented internally of the package and in contact with the contents a rugose sheet material, such as creped paper and the like, and an outer protective sheet material lmited to the inner sheet material by 3 Claims. (Cl. 99-171) means of a suitable adhesive, or merely superposed on the inner sheet material.

Further details and advantages of the invention will be apparent from the following specification and drawings wherein:

Figure 1 is a perspective view of the heat-sealable sheet material partly broken away to show the components thereof.

Figure 2 is an enlarged transverse sectional view taken on lines 2-2 of Figure 1,

Figure 3 is a perspective view of a modified sheet material partly broken away to show the components thereof,

Figure 4 is an enlarged fragmental view of the sheet material shown in Figure 3, and V Figure 5 is a perspective view of a yeast package partly in section made of the heat-scalable sheet material.

Referring to Figures 1 and 2 of the drawings, according to my invention I produce packages and containers from a combined sheet material which comprises a suitable base sheet material I0 preferably united by means of an adhesive Il to a rugose sheet material l2. The sheet designated as the base sheet is intended to be presented on the exterior oi' the package and the rugose sheet is intended to be presented on the interior of the package and to be in direct contact with the materials packaged. Any suitable b; se sheet material I0 is selected depending upon the particular usage of the final product, such as paper, paper board, regenerated cellulose, glassine, parchment paper, rubber hydrochloride, cellulose acetate, ethyl cellulose, vinyl resins, any suitable synthetic resin foils, metal foils and the like. The base sheet material may be treated so' as to impart any desired additional characteristics thereto such as greater imperviousness to the adhesive used, wet-strength, greaseproofness and exibilty. In the case of paper, it may be suitably coated and supercalendered for printing purposes.

The rugose sheet material I2 is relatively porous as compared with the relatively impermeable base sheet I0, and of such structure as to permit migration of the molten or sof-tened adhesive Il to the surface of the rugose porous sheet when a thermoplastic adhesive is used. A suitable rugose porous sheet is creped paper made from sulphite or sulphate pulp. or a mixture oi these, in various basis weights and having a crepe yratio of about 5% to about 100%. Instead of using a creped sheet I may utilize a regularly embossed sheet I5 as shown in Figures 3 and 4. The embossments or rugosities 20 serve to provide an increased surface area in the rugose sheet and function like the corrugations of the creped sheet i2. An unsized or waterleaf rugose sheet material may be utilized to further increase the absorbent quality.

When using a base sheet of Cellophane, sulphite paper, metal foil or cardboard we nd it advantageous to use a creped porous sheet made of light-weight paper tissue relatively lighter in weight than the base sheet, for example, less than 20 lbs. (basis weight 480 sheet 24 x 36 in.) paper sulphite tissue, and having a crepe ratio of about 5 to about 100%. Such tissue sheet is also comparatively porous with respect to the base sheet so that when a thermoplastic adhesive is used it will migrate diierentially in greater amount by weight per unit weight of sheet through the porous sheet rather than the relatively impermeable base sheet so as to generate an adhesive iilm on theouter surface of the relatively porous cover sheet. An important function of the rugose sheet is to provide a greater surface area of the sheet as compared ywith the coextensive area of the relatively flat base sheet. When packaging food products having a high moisture content, such as fresh yeast cakes, for example, which have about moisture content. a bibulous water-absorptive creped sheet is utilized which is placed in contact with the food product. Such sheet will exert a wicking action on any moisture or water droplets that may form or condense on the surface oi the yeast.

Considerable difculty has been previously experienced in packaging fresh yeast cakes because after wrapping the yeast cake the relative humidity inside the package may reach and as the temperature is lowered due to refrigeration or cooler room temperatures droplets of water form on the surface of the yeast cake-which causes discoloration and degradation of the yeast. When yeast cakes are packaged in the sheet material, the moisture droplets will be absorbed by the wicking action of the creped sulphite tissue sheet. Considerable moisture can be absorbed by the creped sheet because the total surface area of the sheet is increased by the creped surface formation of the sheet. The irregularities and protruding portions of the creped sheet tend to rupture 3 any droplets of water that may iorm so that the moisture is rapidly absorbed by the body o! the sheet by capillary action. Y

The rugose porous sheet permits migration of the adhesive layer as previously explained during packaging operations so that overlapped portions of the wrapper may be heat sealed by application of heat and pressure thereto. The adhesive layer furthermore remains as a continuous layer throughout the sheet and serves to protect the contents of the package against moisture loss or entry of moisture when hygroscopic materials or dehydrated foods are packaged.

A further advantage of the use of a creped sheet is that it adds to the bulk of the sheet for a given weight of sheet material and serves to cushion the articles packaged as well as helps to prevent rupture of the base sheet by any sharp edges which may be present in the article packaged, such as hard candies.

The expression rugose sheet" is intended to include any of the previously described sheets which are creped, embossed, corrugated, wrinkled or otherwise provided with rugosities.

I may form packages and containers from the previously described base sheet material on which is superposed a water or moisture absorbent rugose sheet material united with any suitable adhesive for bonding the base sheet and the rugose sheet such as ordinary glues and adhesives commonly used for laminating paper and other flexible sheet materials. I may also use suitable thermoplastic adhesives comprising selected or blended microcrystalline waxes; microcrystalline waxes having one or more added viscosityincreasing ingredients such as various elastomers, resins, gums, rubber, synthetic rubber, isobutylene and butylene polymers. water-insoluble metallic soaps such as aluminum soaps of the higher fatty acids as aluminum stearate, oleate or palmitate in amounts from 1 to 30% by weight; paraffin wax containing any of the previously mentioned ingredients added thereto and in about the same amounts; cellulose derivative compositions; synthetic resins, such as phenol-formaldehyde resins, urea-formaldehyde resins, vinyl resins; asphalt's; natural gums; protein-containing composition such as zein; and casein. These adhesive compositions are utilized for combining the base sheet and the rugose sheet in any known manner. When using thermoplastic hot-melt adhesive compositions having wax as the base ingredient, we may chill the combined sheets at the point of combining so as to control penetration or migration of the composition through both combined sheets. The ingredients of the composition used may be suitably selected and compounded so as to have a suitable predetermined viscosity so as to be non-penetrating with respect to the sheets to be combined. The use of viscosity-increasing ingredients serves (l) to increase the viscosity to a point where a greater weight of adhesive can be applied successfully with the present types of available coating equipment, (2) to make the adhesive of such viscosity that it will penetrate less into the base sheet using, for example, open types of sheets such as board or heavy weight sulphite paper, and yet speed of uniting. temperature of application of the adhesive. chilling of the combined sheets also can be controlled in any known manner to prevent penetration. In this way we obtain a stock sheet which has a continuous flexible uniform highly moistureproof layer of the intermediate adhesive composition without any of the composition being present on the outer exposed surfaces of the sheet.

I 11nd it advantageous to use a thermoplastic adhesive lm of a basis weight of at least about 1*/2 to 2 times (or preferably more) the basis weight of the porous rugose sheet when using, for example. a paper base sheet of 1'7 lb. sulphite and a porous rugose sheet consisting of a 9 1b. sulphite paper sheet creped to 10 1b. basis weight (basis weight 480 sheets 24 x 36 in.) When such amount of intermediate adhesive film is used there will 'be suilicient adhesive composition to bond the sheets together, and also upon application of heat and pressure, the adhesive composition will penetrate and saturate the creped sheet to such extent as to migrate to the surface to provide a suitable bonding lm at the outer surpermit of suiilcient penetration through theV rugose porous sheet to eiect the seal when heat and pressure are applied, (3) to bring up the adhesiveness of certain hot melt materials such as paraffin wax, in order to make them usable for the purpose of this invention. The conditions under which the sheets are combined, sllh .as

face thereof.

'I'he combined sheet material may be utilized for forming packages by wrapping any desired article by completely enclosing the article with the rugose sheet l2 in contact with the article and the -base sheet I0 exposed outside of the package. When using a laminated sheet consisting of a relatively impermeable base sheet, -a thermoplastic adhesive and a relatively rugose porous cover sheet, overlapped portions of the sheet can be readily sealed by heat and pressure to form a seam, the adhesive migrating through the porous sheet to form a bond at the interfaces of the overlapped portions of the sheet.

I may also make preformed containers, bags and the like from my sheet material by cutting suitable blanks of my sheet material and then forming the seams by applying heat and pressure thereto so as to cause the adhesive to migrate through the porous rugose sheet and provide a. bonding medium. The seams may be formed either by bringing portions of the blank into contact so that the porous rugose sheet overlaps the base sheet. In each case an adhesive film will be generated at the overlapped interfaces when heat and pressure are applied thereto. I'he sheet materials may also be fabricated into suitable containers by any conventional procedures for forming bags, cartons' and containers from' suitable blanks of our sheet materials and by gluing the seams or overlapped portions with conventional adhesives.

The following are typical specific examples of sheet materials for making packages and containers, weights being given per ream (480- 24x36):

This combined sheet is eminently suitable for packaging fresh compressed yeast cakes. The outer exposed surface of the creped cover sheet is water and moisture absorptive and is substantially unaltered from its original characteristics after being combined with the base sheet.`

Erample 2 Same components are used as in Example 1 and having about 4 to 5Albs. parailln wax applied on exposed surface of the supercalendered sulphite base sheet. The external paratlin wax coating serves to give additional protection to the yeast and serves to supply a sealing vmedium -for contacting overlapped portions of the super- This sheet has excellent workability for machine packaging and is especially suitable for packaging dehydrated bouillon cakes. Any pinholes in the aluminum foil are completely sealed by the adhesive so that the highly Ahygroscopic boullion is fully protected.

Examplel 4 Pounds Component Weight Per Ream l. Waxed creped sulphite sheet 1L 0 2. Micr e wax M. P. 145 F 20.0 3. Begenerated cellulose (cellophane) (base sheet). 21.0

This sheet is suitable for packaging candy.

The previously described sheetmaterials are suitable for packaging or wrapping any desired articles particularly when thermoplastic adhesives are used for bonding the sheets.' Overlapped portions of. the wrapper can be sealed by applying heat and pressure thereto as previously explained to form a very strong and tight seal. The inner adhesive film is protectedy against damage, puncture, abrasion, adhesion ofy foreign substances, dirt, etc., by being covered-by the porous 'cover sheet. In packaging certain items that do not have to be hermetically sealed our wrapper can be used very effectively for protective purposes without necessarily sealing the overlapped portions of the wrapper by heat and pressure.

The previously described sheet materials having an intermediate thermoplastic adhesive have many characteristics which render them highly suitable as wrappers for foodstuis. Such sheet material is moistureproof in both at condition as well as after converting operations as the adhesive layer is highly flexible, water and moistureproof. The sheet is very exible and easily folded and has a minimum of spring-back when folds are made at the end of packages. Thus aminimumof heat is required for forming seals at the overlapped portions and thus the packaged contents are less likely to be deteriorated by the heat applied. Some materials, such as yeast, are very sensitive even to slight heat. The sheet materials provide very effective heat-sealable wrappers as a minimum of heat is used for sealing the package. On account of the :flexibility 'and' continuity of our intercalated im the sheet material produces square and well formed packages. No disruption of the adhesive filmI will occur at the corners of the folds when packages are made as the porous sheets serve to reinforce and protect the intermediate film in these areas where the previous types of exposed coatings are liable to crack and peel during folding and creasing operations.

The described sheet materials are suitable. for

forming bags. receptacles, containers, cartons.v

and IWrappers. In making bags. .cartons and receptacles of any kind the base sheet provides the inner wall of the vcontainer in contact with the materials packaged therein. Y

Numerous changes and modications may be made in the speciic embodiments of this`invention. utilizing the essential and signicant .features of .the-invention as fully disclosed herein. It is intended to include such modifications within the scope of the appended claims.

I claim:

1. A yeast package comprising a cake of fresh yeast completely enclosed in a' sheet material comprising a relatively impermeable base sheet material positioned externally of the package, a thermoplastic and moistureproof adhesive coating on said base sheet, andV a relatively porous creped water-absorbent tissue sheet adhered to said thermoplastic adhesive, said creped sheet being in contact with said yeast cake and capable of absorbing moisture droplets formed on the surface thereof, said adhesive Ibeing conned to the inner surface of said rugose sheet and the outer exposed surface of said rugose sheet being subadhesive film generated at the inter faces of said f overlapped portions by application of heat and pressure to said selected portions.

2. A yeast package comprising a cake' of fresh yeast completely enclosed in va sheet material comprising a relatively impermeable paper base sheet material positioned externally of the package, a thermoplastic adhesive coating on said Y base sheet, and a relatively porous normallycreped moisture-absorbent tissue paper cover sheet adhered to said thermoplastic adhesive, said creped sheet being in contact with said yeast cake and capable of absorbing moisture droplets formed on the surface thereof, said adhesive being confined to the inner surface of said cover sheet and the outer exposed surface of said creped sheet being substantially unchanged from its original characteristics, said adhesive being present in amount upon application of heat and pressure to selected portions of said sheet material to migrate differentially through said creped sheet rather than through said base sheet material to generate an adhesive sealing lm on lthe outer surface of said creped sheet, selected portions of said sheet material being overlapped. and adhered together by an adhesive lm generated at the inter faces of said overlapped portions by application of heat and pressure to said selected portions.

3. A yeast package comprising a cake of fresh yeast completely enclosed in a sheet material 7 comprising a relatively impermeabile paper base sheet materiel positioned externally et the package, a thermoplastic and meisturepmef ad hesive coating on said base sheet, and a. relatively porous erexied moisture-absorbent paper tissue sheet adhered to said thermoplastic adhesive. said creped sheet being in contact with said yeast cake and capable of absorbing moisture droplets formed on the surface thereof. said adhesive heing confined to the inner surface of said oever sheet and the outer exposed surface of said creped sheet being substantially unchanged from its original characteristics, said adhesive comprising microcrystalline wax. said adhesive in amount upon application of heat and pressure to selected portions o! said sheet material to migrate differentially through said creped sheet rather than through said base sheet material to generate an adhesive sealing lm on the outer surface of said creped sheet, selected portions of said sheet material being overlapmd; and adhered together by an adhesive film generated at the later im ci said overlapped portions by applicatien of heat and pressure te said selected portloiisn o A. FARRELL.

me of this patent:

UNIT@ STATES Pif-rms Number Name Date 1,538,277 Duin. May 19, 1925 '1,917,454 Mazzola July 11, 1933 2,171,775 Wilshire Sept. 5, 1939 FOREIGN PATENTS Number Country Date 11,706 Great Britain 1905

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