US2099301A - Paper wrapper for commodities - Google Patents

Description

Nov. 16, 1937. c. s. HAMERSLEY ET AL PAPER WRAPPER FOR COMMODITIES Filed Sept. 21, 1933 ini' H INVENTORS Ca rLJLlIa/ma'a BY Jamar 6.Mbm9,

Patented Nov. 16, 1937 Carl S. Hamersley, New York, N. Y.,and Sumner O. Fairbanks, Passaic, N. J.; said Fairbanks assignorto said Hamcrslcy Application September 21,1933, Serial No. 690,394

10 Claims.

Our present invention relates generally to the wrapping art, and has particular reference to a new and improved wrapper of sheet material such as paper.

While we have herein illustrated, and shall hereinafter describe, a transparent paper wrapper of the character which is designed primarily for use in wrapping a commodity such as a bread loaf, nevertheless it will be understood that cersolvent at the time of the wrapping, the same objections obtain.

Apart from the foregoi g reasons which prevent an ordinary adhesive to be used, an added dimculty presents itself when the wrapper is of waxed paper, because the adhesive must be of a character which will not only adhere to the War: but which will penetrate through the wax when the sealing is to be effected; and ordinary ad- 10 tain phases of our invention are not necessarily hesives do not meet with these requirements.

restricted to this particular type of wrapper or to this particular use.

A general object of our invention is to provide an improved wrapper whose application around a l commodity is facilitated and rendered more se-- cure. More particularlya we aimsto provide an improved paper wrapper having opposite margins which are adapted to be folded and sealed, under a 35 It is a more particular object to provide an imso commodities, it is customary practice to employ .are coated with a bonding material of the fore- 30 proved wrapper of the waxed paper type, although certain phases of our invention are not necessarily restricted to sheet material of this character.

In the wrapping of bread, cake, and similar a wrapper of waxed paper or the equivalent, and

' to effect the actual wrapping procedure by means of a machine which tucks in the opposite ends of the wrapper, folds them, and applies heat and 86. pressure for the purpose of melting the wax and 40 cure; and by means of our present invention we 4 of improved sealing qualities are peculiar.

thereby effecting a wax bond between the inter= leaved ends of the wrapper. The sealing effect which is thus produced is quite satisfactory, but from a number of aspects it is not adequately sehave provided a wrapper which is adapted to be sealed around such a commoditywith greater security andfirmness. k

The problems involved in providing a wrapper The mere use of a conventional type of adhesive is un feasible. If the adhesive is to be applied in a moist condition at the wrapping machine, it impairs the smooth operation of the latter, and it is 50 a messy proceeding which is thoroughly undesirable, especially since edible commodities are being handled by the wrapping machine at the same time. If the adhesive is applied to the wrapper during its manufacture, so that it is merely neces- It is a feature of our present invention to provide a bonding material which is readily applicable to the wax during the initial manufacture of the wrapper; which is normally of no appreciable viscidity; and which is adapted to become .operativeunder the mere application of heat and pressure, requiring no messy procedure at the wrapping machine and permitting the latter to function in its normal manner. The bonding material of our present invention has the characteristic of becoming substantially tacky under the slight temperature rise which is produced at the wrapping machine; and it has the special advantage of-being adapted to penetrate through the wax and to effect'a'flrm bonding action with the paper itself when heat and pressure are applied.

It is another feature of our invention to provide a wrapper in which certain opposite margins going type, and in which the midportion of the wrapper, between said margins, is purposely thickened toadegree which makes the midportion at least as thick as the coated margins. This permits the wrapper to be formed as a continuous roll, which may be cut'into suitable wrapper blanks at the wrapping machine. If the midportion were not thickened, the thickness at the margins would prevent the material from being efiiciently wound into rolled form.

Our invention is predicated upon the discovery that resins, in general, and certain specific resins (preferably synthetic), in particular, embody the desirable characteristics which are necessary to accomplish the present objectives. The bonding material which we employ, is, therefore, composed essentially of a resin, mixed with. just sufllcient plastlcizer to destroy the natural brittleness of the resin.and to lower the melting point to approximately the melting temperature of wax. j A mixture of this character is unreactive toward wax; has no appreciable normal viscidity; becomes substantially tacky when subjected to a .slight temperature rise; and has the important sary to wet the adhesive with water or similar advantage of penetrating through the wax to form a secure bond with the paper itself when heat and pressure are applied. The latter ability of the present material is probably due to the fact that its viscosity is greater than that of wax.

We achieve the foregoing objects and advantages, and such other objects and advantages as may hereinafter appear or be pointed out, in the manner illustratively exemplified in the accompanying drawing, wherein Figure 1 is a diagrammatic view of the manner in which a. strip of wrapping material of the present character may be advantageously manu factured;

Figure 2 is an enlarged cross-sectional view taken substantially along the line 22 of Figure l;

Figure 3 is a plan view of a section of the completed strip of wrapping material of the type produced by the apparatus of Figure 1;

Figure 4 is an enlarged cross-sectional view taken substantially along the line 4-4 of Figure Figure 5 is a perspective view of a wrapped bread loaf or the like; and

Figure 6 is an enlarged fragmentary cross section through certain interleaved and sealed layers of the material, showing the manner in which the sealing is accomplished.

In accordance with one method of carrying out our present invention, a main roll of suitable paper it is caused to be guided around a guide roller ii submerged in a bath of molten wax it.-

At the same time, an auxiliary roll i 3 of narrower material is similarly caused to be guided around a guide roller it submerged in the bath l2, whereby the two wax-coated strips may then be caused to pass simultaneously between a pair of pressure rollers 55 as they emerge from the bath. The strip iii is arranged in a manner'whereby it will overlie the longitudinal midportion of the main sheet iii, and the step of passing between the rollers it results in squeezing out excess wax and at the same time firmly bonding the narrower strip i3 to the main strip it.

This assembly is then caused to pass over two or more doctor rolls i6 which dip into a bath or baths ll of the present type of bonding material. Preferably, each of the rolls i6 is formed of a series of spaced discs, as shown most clearly in Figure 2, whereby the bonding material 11 is applied to the marginal portions tr the sheet l0 along a series of substantially parallel line areas. This produces a series of ridges l8 of the bonding material, as shown most clearly in Figure 4.

The resultant strip is then passed over suitable cooling rollers, and is ultimately wound onto a mandrel or drum. A section of the resultant strip is shown most clearly in Figures 3 and 4. It will be observed that the medial band I3 is securely bonded to the main strip ID by means of an intermediate layer of wax l9, and that the entire sheet is surrounded and enveloped by a similar layer of homogeneous wax. This coating is designated by the reference numeral 20 in,

Figure 4. The medial strip or band l3 may serve a dual function. In the first place, it thickens the midportion of the wrapping material between the coated margins, so that the resultant thickness at the midportion is greater than that of the body portion of the material, and is at least as thick as the coated margins. This permits the material to be rolled efiiciently onto a drum or the like, since the midportion of the roll is there by permitted to form a solid mass which is firmly compacted and which holds the roll in a stable condition. The edge portions of the roll are relatively uncompacted, being thinner, but this does this surface which is exposed outwardly when the wrapper is applied to a commodity.

Obviously, the medial band it, which may be of paper or similar material, serves also to reinforce the wrapper at the midportion thereof; and when an individual wrapper blank is enveloped around a commodity, such as a bread loaf, as shown in Figure 5, the medial band it serves as an efflcient reinforcement for the entire wrapped commodity.

The bonding material which we employ is unreactive toward wax, and is adapted to be eflicientiy applied to the wax, as shown at is in Figure 4, this application being preferably accomplished -in the manner shown in Figures 1 and 2. Under normal conditions, the ridges or masses of bonding material it are of no appreciable viscidity and rest substantially on the outer surface of the wax coating it, although perhaps a slight merging of the ridges with this layer of wax may take place. This normally dry condition of the wrapper permits it to be efliciently rolled, packed, shipped, and handled, without any special precautions, and without any likelihood of annoying tackiness. When the wrapper is used, however, the advantageous characteristics of our present bonding material become mani-' fest.

We have not illustrated a wrapping machine, nor is our invention restricted to the use of any particular type. of wrapping machine, but it will be understood that severed blanks of the wrapping material are causedto be enveloped around a commodity so that the ends may be interfolded in the manner designated generally by the reference numeral 22 of Figure 5. "Heat and pressure are then applied to these ends, and when this is done the wax and the bonding material melt. The bonding material being of greater viscosity than the wax, each mass of the material penetrates through the wax beneath it and comes into direct contact with the paper. Under pressure, a direct and highly emcient and tenacious bond is thus effected between the two layers of superposed paper; and as soon as the-wrapping machine discharges the product, the wax and the bonding material resume their normal untacky condition and become hard and non-- viscid.-

The efficiency with which the bond is effected is shown most clearly in Figure 6, in which 23 I layers 21 and 28. The line 29 is shown in dot-- and-dash, because it exists before the heat and pressure are applied but disappears when the layers 26 and'21 melt and merge with each other.-

The two masses 30 of the present bonding material are illustrative of the manner in which the areas or ridges I8 are believed to act under the method of manufacture or use.

of bonding material, and may be thickened at heat and pressure that is applied. The material may originally have rested on the layer 26, or on the layer 21, or both, but in any event the melting of the material causes it to penetrate through the wax layers" and 21 until it comes into It will be understood that at the folded and sealed ends of the wrapped commodity there will sometimes be more than two! ers of paper bonded together in the manner fiown in Figure 6, and Figure 6 cannot be said'to be the cross-section along a specific line of Figure 5 for this reason. However, the action illustratively shown in Figure 6 as taking place between two. superposed layers of paper takes place in substantially the same manner wherever masses of the bonding material l8 encounter an adjacent layer of the material under heat and pressure.

While we have found that resins, in general, may be employed for our present purpose, we prefer to use a resin oi the class which includes coumarone-indene, ester gum, gum dammar, kauri gum, cope], and the like. Of these, we have found coumarone-indene to be particularly advantageous and useful in carrying out our present objectives. Whatever resin is used will be mixed with a suilicient amount of plasticizer to lower the melting point of the mixture to substantially that of wax. While any well known type of plasticizer may be employed, depending largely upon choice, we prefer to use a plasticizer of the class which includes tri-cresyl-phosphate, di-butyl-phthalate, tri-phenyl-phosphate, chlorinated diphenyl, and the like. Of these, we prefer tri-cresyl-phosphate, and, in fact, a satisfactory bonding material may consist, for example, of a mixture of about 72% of coumarone-indene and about 28% of tri-cresyl-phosphate.

Modifications in the proportions may obviously be made by those skilled in the art to meet differing requirements of melting temperature and the like. Care should be taken, however, to add just enough plasticizer' and not too much, because if an excess amount of plasticizer is used the mixture may partake of an undesirable viscidity under normal conditions. Similarly, if insufllcient plasticizer is used, the bonding material may not melt to a sufficient degree when the heat and pressure of the wrapping machine are applied.

While we have illustrated and described our invention in connection with a continuous strip of wrapping material, it will be understood that this is merely a preferred method of carrying out our general objectives, and that our invention is not necessarily restricted to any continuous Similarly, while we have shown the manner in which our invention may be employed in connection with waxed paper, since this is the preferred type of paper in many instances, nevertheless many phases of our invention, including the bonding material and its method of use, are not restricted to employment with waxed paper. Ordinary glassine paper or regenerated cellulose may be similarly coated along its margins with the present type the midportion in the manner hereinbefore described to carry out the general: purposes of our invention. v v

Furthermore, while we have iliustratively shown the preferred manner of thickening the mi'dportion of the wrapper by means of an extra strip or band of paper or the like, nevertheless it will be understood that this thickening may be accomplished in other ways, as, for example, by interleaving a separate strip of material with the wrapping material without necessarily bonding it thereto by means of wax; also by thi kening the midportion by the addition of extra wax; or in other ways which will suggest themselves to those skilled in the art. I

' Wherever we have used the term normal" herein and in the appended claims, we refer to room temperature conditions. By the same tokenythe term "slight temperature rise" refers to an increase of temperature of the type which is accomplished by heat at a wrapping machine; and we do not mean to allude either totemperature rises of lesser degree nor to extreme temperature rises that are not encountered in ordinary use of wrappers of the present character.

The term wax" includes, of course, such materials as parailln or the like which are customarily used in the manufacture-of what is usually referred to as waxed paper.

In rgeneral, it will be understood that changes in the details, herein described and illustrated for the purpose of explaining the nature of our invention, may be made by those skilled in the art without departing from the spirit and scope of the invention as expressed in the appended claims. It is, therefore, intended that these ,details be interpreted as illustrative, and not in a limiting sense.

Having thus described our invention, and illustrated its use, what we claim as new and desire to secure by Letters Patent is 1. A waxed paper wrapper having along cer-. tain margins a coating of bonding material which is unreactive toward wax and of no appreciable normal viscidity, said material having a greater viscosity than wax and being substantially tacky at the melting temperature of wax.

2. A. waxed paper wrapper having along certain margins a coating of bonding material which is unreactive toward wax and of no appreciable normal viscidity, said material having a greater viscosity than wax and being substantially tacky at the melting temperature of wax; said material consisting essentially of a resin.

3. A waxed paper wrapper having along certain margins a coating of bonding material which is unreactive toward wax and of no appreciable normal viscidity, said material having a greater viscosity than wax and being substantially tacky at the melting temperature of wax; said material consistlng essentially of a resin of the class which includes coumarone indene. ester gum. gum dammar, kauri gum, and copal.

4. A waxed paper wrapper having along certain margins a coating of bonding material which is unreactive toward wax and of no appreciable viscosity than wax and being substantially tacky at the melting temperature of wax; said material comprising a resin mixed with a plasticizer.

6. A waxed paper wrapper having along certain margins a coating of bonding material which viscosity than wax and being substantially tacky at the melting temperature of wax; said material comprising a resin mixed with a plasticizer oi the class which includes tri-cresyl-phgsphate, dibutyl-phthalate, tri-phenyl-phosphate, and chlorinatecl diphenyl.

8, A waxed paper wrapperhaving along cerv tain margins a coating of bonding material which is unreactive toward wax and of no appreciable normal viscidity, said material having a greater viscosity than wax and being substantially tacky at the melting temperature of wax; said material comprising a mixture of coumarone indene and a plasticizer.

9. A waxed paper wrapper having along certain margins a coating of bonding material which is unreactive toward wax and 01' no appreciable normal viscidity, said material having a greater viscosity than wax and being substantially tacky at the melting temperature of wax; said material comprising a mixture of coumarone indene and tri-cresyl-phosphate.

I 10. A waxed paper wrapper having along oer= tain margins a coating 01' bonding material which is unreactive toward wax and o! no appreciable normal viscidity, said material having a greater viscosity than wax and being substantially tacky at the melting temperature of wax; said material consisting of a mixture of about 72% coumarone indene and about 28% tri-cresyl-phosphate, CARL S. HAMERSLEZ. SUMNER; C. FAIRBANKSG

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