US2228785A - Sealed package and method of making same - Google Patents

Description

Jan. 14, 1941. M. H. SMITH ETAL SEALED PACKAGE AND METHOD OF MAKING SAME Filed March 1, 1939 f] gave/250m: u/al! 'fi Fe 21. M54 W W M my Patented Jan. 14, 1941 UNITED STATES 2,228,785 PATENT OFFICE SEALED PACKAGE AND METHOD OF MAK- ING SAME Marshall B. Smith, Neenah, Wis., and Roy A. Nash, Bronxville, N. Y., assignors to Marathon Paper Mills Company, Rothschild, Wis., a corporation of Wisconsin Application March 1,

8 Claims.

This invention relates to the sealing of articles which have been wrapped in sheet materials. More specifically, this invention relates to the wrapping of bread in sheet materials such as paper, waxed paper, Cellophane (regenerated cellulose), Glassine, parchment paper, cellulose acetate and the like, and sealing the ends of the overlapped portions of the wrapper with a seal which is secured by heat and pressure. This invention also relates to the application of seals, bands, and the like, to a paper package and to any desired portion of said package.

At the present time, a large number of food items, particularly bread, are wrapped in waxed paper. It is the practice to overlap the end portions of the wrapper, particularly at the ends of the wrapper, and seal the seams by heat and pressure. It has been found that the strength of the seal so formed is comparatively weak and can be readily opened by a slight pulling force. Furthermore, the seal thus produced does not insure perfect sealing of the contents. A similar difficulty arises in the packaging of cartons and other similar articles in an outer wrapper of waxed paper and the like for moisture-proofing and protecting the contents within the carton. Considerable difiiculty has been encountered in properly sealing the overlapped portionof the outer waxed wrapper, so as to insure a perfect seal for the contents of the package.

The object of this invention, accordingly, is to overcome the above mentioned diificulty by providing sealing means for the ends of wrappers on bread loaves, cartons containing contents which are to be protected against moisture or loss of moisture, and any other commodities which are wrapped in waxed paper, inorder to protect same against deterioration or spoiling by loss of moisture or entrance of moisture.

Further details of the invention will appear from the following specification and the appended drawing wherein Figure l is a perspective view of a loaf of bread wrapped in waxed paper having the ends thereof sealed in accordance with the invention,

Figure 2 is a perspective view of the sealing label,

Figure 3 is an exploded fragmentary perspective view of the bread package and the end seal label,

taken on lines 4-4 of Figure 3, and

Figure 5 is a fragmental perspective view of the sealed package showing the end seal partially peeled therefrom.

According to the present invention, the article such as a loaf of bread is wrapped in a wrapper of ordinary waxed paper 20. The overlapped ends of the package, 2|, as shown in Figure 1, are pressed together and adhered by means of the Figure 4 is an enlarged cross-sectional view 1939, Serial No. 259,248

coating of wax M or wax-like composition, which is present upon the surface of the wrapper 20. The adhesion of this bond provided by the wax, or wax-like coating upon the wrapper 20 is ordinarily not very strong. Furthermore, the overlapped end portions ZI are not completely sealed in the ordinary packaging machines which are generally used today in bakeries and the like. Consequently, after the bread packages are placed upon the shelves in stores, there is considerable loss of moisture at the ends of the package, unless some provision is made for positively sealing the ends and retaining the wrapper in sealed relation.

According to the present invention we provide a label or seal having a composition or coating l2 upon its inner surface, as indicated in Figure 2. The coating composition 12 provided on the seal is of such character that when it is applied to the ends of the package and pressed thereagainst by heat and pressure, the composition will fuse and unite with the wax coating upon the wrapper 20, and thereby form a perfect seal or union therewith. A suitable coating composition for this purpose is a heat sensitive or thermoplastic waxrubber composition of the character disclosed in Abrams Patents Nos. 2,054,112 and 2,054,115. A satisfactory coating composition for use upon paper labels comprises a mixture of paraflin wax and rubber, the rubber content being from 6 to about 30% by weight of the composition, the mixture when used having a viscosity of at least 8,000 secs. (50 cc. measured on a Scott viscosimeter at 90 0.). We have found that when an end label or seal coated with such composition is applied with the coated surface against the wax coating of the wrapper 20 by heat and pressure, the coating composition will fuse with the wax, forming a unitary bond or seal which adheres with great tenacity over its entire coated surface to the waxed surface of the wrapper 20 and can be removed therefrom only with considerable difficulty.

Inasmuch as the packaging of commodities with waxed paper, especially in connection with the packaging of bread, is usually carried out in machinery supplied with heat sealing elements for sealing the ends of the package, our thermoplastic coated heat seal end label is especially adapted for use in conjunction with such machinery. For example, we may supply our end seal labels in the form of a long roll of continuous labels which are fed and cut off at the point where they are to be applied to the end of the wrapped loaf of bread. The end seal may be applied just after the wrapped loaf of bread has passed the final folding element in the bread wrapping machine. The residual heat present in the wrapper at this point is sumcient to soften the coating l2 on the end seal, thereby serving to locate the end seal in place upon the end of the package and holding same in position for the subsequent action of the element in the machine for applying heat and pressure to the label to seal samefirmly in place.

The coating I2 which we provide upon our label [0 may be made from any suitable type of heat sensitive or thermoplastic compositions. As previously stated, we may use suitable compositions comprising wax and rubber, or wax-like and rubber-like substances. We may, for example, employ a composition containing any type of suitable wax, such as parafiin wax, carnauba, beeswax, microcrystalline waxes, or amorphous waxes and any synthetic wax-like substances. With these waxes we may combine a film forming substance such as rubber, gutta percha, synthetic rubbers, polymers of isobutylene, resinous materials, Bakelite or other phenol resins, glyptal resins, phthalic anhydride resins, ethyl or glyceryl esters, rosin or the like. These substances may be compounded in any suitable proportion and in any known manner to produce a heat sensitive composition which may be coated upon our labels for use in sealing same to waxed sheets and the like. The composition we use is heat sensitive upon application of heat thereto and is adapted to merge or coalesce with ordinary wax coatings upon usual waxed papers used for packaging purposes. Furthermore, our coated seals or labels are adapted to be used upon any type of shellaced or coated papers which are difficult to seal by the use of glues or similar adhesives which are available on the market today. v

Although the invention is; especially adapted for the sealing of ends of wrapped packages, it is obvious that labels, stripes, bands and the like may be similarly applied to any part of the body of the package. For example, as shown in Figure 1, we may apply labels or seals indicated by numerals 30 and 3| to any body portion of the package. The seals 25 are applied to the package in a similar manner as the end seals In by means of heat and pressure, thereby causing same to tenaciously adhere to the wrapper. The end seals 25, as well as the seals 30 and 31, may be provided with any desired ornamentation or printed matter II.

It is obvious that numerous departures and modifications of the invention may be made without departing from the spirit of the invention as defined in the appended claims.

We claim:

1. As an article of manufacture, a wrapped article comprising in combination, a Waxed wrapping material secured around the lateral surfaces of the article and at the ends of the article, a supplementary sheet substantially overlying the ends .of the article and covering any interstices in the wrapper, and secured thereto by a thermoplastic composition comprising a waxy constituent and film forming constituent, the thermoplastic composition being coalesced with the waxed surface of the wrapping material.

2. A wrapped article comprising in combination, a waxed wrapping material secured around the lateral surfaces of the article, overlapped end folds of the wrapper at the ends of the article, a supplementary sheet on the end folds of the wrapper, and secured thereto by a wax-rubber composition on the supplementary sheet, said wax-rubber composition being substantially coalesced with the waxed surface coating of the wrapping material.

3. As an article of manufacture, a wrapped article comprising, in combination, waxed wrapping material aroundthe lateral surfaces of the article, overlapped end folds of the wrapper at the ends of the article, and supplementary sheets on the wrapper and secured thereto by a heat 5 sensitive composition comprising wax and resinous materials, the supplementary sheets and the composition forming seals enclosing the interstices of the end folds.

4. As an article of manufacture, a wrapped article comprising, in combination, a waxed wrap ping material completely enclosing said article, and a supplementary sheet secured by heat and pressure to said'wrapping material by means of a heat sensitive thermoplastic wax-rubber compol5 sition.

5. A method of packaging articles provided with a waxed wrapping material secured around the lateral surfaces of the article, and having overlapped folded end margins secured on the ends of the article, which comprises applying supplementary sheets having a thermoplastic heat sensitive coating composition thereon having a waxy constituent and a film forming constituent onto the overlapped folds at the ends of the article, and applying heat and pressure to the supplementary sheets to adhere same to said wrapping material until the said coating composition has substantially coalesced with the wax coating upon said wrapping material.

6. A method of packaging articles in waxed paper which comprises applying supplementary sheets having a heat sensitive coating composition thereon having a waxy constituent and a firm forming constituent into contact with the waxed surface of the waxed paper, and applying suflicient heat and pressure to the supplementary sheets until said composition has sufliciently coalesced with the wax coating on said paper to adhere to the paper.

7. In a method of packaging articles involving wrapping waxed paper around the lateral surfaces of an article, folding the end margins of the wrapper into overlapping folds to cover the ends of the article, smoothing the ends with heat and pressure sufllcient to soften the wax and preliminarily stick the folds in place, the step of applying supplementary sheets provided with a waxrubber coating composition thereon to the overlapping folds at the ends of the article while same 5 is still warm, thereby securing said supplementary sheets into place, and applying sufilcient heat and pressure at opposite ends of the article until said coating composition has sufficiently coalesced with the wax coating of said wrapper to seal the end folds of the wrapper securely.

8. A method of packaging which comprises applying a label having a thermoplastic heat sensitive coating composition comprising a waxy constituent and a film forming constituent to a predetermined area of the overlapped portions of a waxed wrapper of a completely wrapped heat sealed package while the package is still warm and retains residual heat from the heat sealing operations whereby said label is definitely re- 55 tained in position on said predetermined area and applying sufiicient heat and pressure to said positioned label until the coating composition on said label has sufficiently coalesced with the wax coating of the wrapper to seal the package 70 securely.

MARSHALL H. SMITH. ROY A. NASH.

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