US1953183A - Method of reenforcing and sealing cartons and material therefor - Google Patents

Description

A ril 3, 934. w. w. MLAURIN METHOD OF REENFORCING AND SEALING CARTONS AND MATERIAL THEREFOR Original Filed April 18, 1931 Patented Apr. 3, 1934 rm'rnomor nanuroa'cmo AND SEALING cAa'roNs arm 'MATERIAL 'rnnnnroa William w. McLaurin,

Broo kfleld, Masa; om

Colony Trust Company executor of said William W. McLaurin, deceased Original application April I8, 1931, Serial No,

Divided and'this application January 25, 1933, Serial No. 653,447

10 claims; (01. 216-62) Thisinvention relates to methods of uniting sheet materials to articles of work for various purposes, such as reenforcing, protecting, sealing, and the like, and to adhesivelycoated sheet 5 materials adapted for these uses. While not limited thereto, the invention is especially concerned with the manufacture and sealing of cartons, boxes, and similar containers, and with reenforcing and sealing, tapes adapted for use on 10 such containers. p r y In the usual methods of making cartons, a carton blank is scored and folded and two side edges of the carton are brought into approximately abutting relationship where they later are secured together by a strip of reenforcing tape which is adhesively united to the margins adjacent tothe abutting edges. This reenforcing operation is performed while the cartonis in a flat or knocked down condition. In using the carton, it is set up, filled, and closed by folding over the flaps in the proper order',,and then is sealed by securing the carton flaps in-their foldedposition nby'a sealing tape. 7

Both the sealing and reenforcing or stay tapes as commonly used for these purposes are secured to the carton by a water'soluble adhesive of some kind. If such cartons are subjected to a moist atmosphere for long periods of time, as for ex- -ample, in ocean shipments through warm cli- 30 mates the adhesives'which unite the sealingand stay tapes to the carton are very likely to become softened to such an extent that they will let go.

This 'diilicultyhas long been recognized and many attempts have. been madeito overcome it.

:5 For example, the reinforcing tapes have inscme cases been securedibymetallic fastenings to the carton, or vhave been dispensed with altogether and the sides of thecartonsecured together by metallic fastenings. Various kinds of "water'- to proof" or, more correctly, water-resistant adhesives have been used. For example, water glass is used to some extent in sealing cartons but is objectionable because of its extreme brittleness and the fact that it dries slowly. The most satis- L5 factory of the water resistant adhesives for these purposes, considering the various requirements,

including that of price, is asphalt, or a mixture in which asphalt is an important constituent.

Tapes coated with such materials, while intro- 0 duced some years agio, have never-gone into use to larged scale illustrating a any substantial exten Theseadhesives must be softened sufficiently by heat to bond them to the carton, and while tapes coated with them can readily be applied by hand methods, it is ex-- tremely diflicult to apply them in taping or sealing machinesat speeds satisfactory to the trade. In addition, the nature of these adhesives is such that it introduces serious practical difficulties in the handling and cutting of the tapes in taping and sealing machines. It is still, therefore, almost the universal practice to use water soluble adhe--'v sives in applying sealing and reinforcing or stay tapes to the cartons. r r

The present invention deals particularly with these considerations. It aims to improve themethods of applying sheet materials to articles of work with water resistant adhesives with a view to overcoming difliculties of the character above. mentioned. It is a particular object of the I invention so to improve these methods and materials as to permit the vuse of water resistant adhesive in the reenforcing and sealing of cartons at speeds comparable to those used in reenforcing and sealing cartons by existing methods. I v.

v The nature of the invention will be readily understood from the following description when read in connection with the accompanying drawing, and the novel features will be particularly pointed out in the appended claims. i

In the drawing,

Figure 1 is a perspective view, somewhat diagrammatic, illustrating an apparatus with which steps of the method devised by this invention may conveniently .be practiced;

Fig. 2 is a perspective view illustrating one way to in which a carton may be reenforced and sealed;

Fig. I3 isaperspective view of a portion of a reenforcing or sealing tape embodying features of this invention; a Fig. 4 is a sectional view of another form of 90 tape made in accordance with :this invention;

and

a Fig. 5 is a cross-sectional view on a greatly en'-,

tape-madein acc'ordance with this invention. J

According to the method of the present invention a temporary attachment of the sheet material to the carton or other article of work is first produced, and in connection with such attachment awater resistant adhesive is interposed 10o between said material and the work. Subsequent- 5 In the reenforcing and sealing of cartons the method is most conveniently practiced with the aid of a novel tape disclosed in the parent application of which this case is a division. This tape comprises a backing strip 2, Fig. 3, of suitable sheet material, such as fabric, paper, or a combination of fabric and paper. One side of this tape is coated with a water resistant adhesive 3. This adhesive preferably is substantially devoid of tackiness at normal temperatures but is adapted to become tacky or sticky when heated to temperatures substantially above normal. It may consist of asphalt, or of a composition such as that disclosed in the Lord Patent No. 1,684,873. On this coating of water resistant adhesive is a superficial coating 4 of a watersoluble adhesive which may be of any suitable nature, such as the common animal, vegetable, or fish glues. In Fig. 3 this coating is shown covering only a part of the adhesive coating 3, but usually the entire surface of the coating 3 will be covered by thecoating 4. Y

Such a tape can be initially applied to the cartons in the ordinary taping and sealing machines. The tape usually is brought to these machines in rolls, and the machine is equipped with means for unwinding the tape, applying a suitable length to a carton, moistening the gummed surface of the tape on its way to the carton, and cutting the tape at the proper intervals. some parts of such a mechanism are indicated diagrammatically in Fig. 1, the strip of tape unwound from the supply roll being shown at 2 and the gummed or adhesively coated surface of the tape being illustrated as running in contact with a moistening roll 5. This tape is shown with its forward end applied to the carton blank 6 where it covers the joint 7 at the meeting edges of the sides of the carton.v A proper length of tape will be cut off to substantially cover this joint.

The initial attachment of the tape to the cartion is poduced through the action of the water soluble coating 4 of gum or adhesive. Subse quently the layer of asphalt 3 or other water resistant adhesive must be softened siniiciently to bond it securely to the carton. This result can be accomplished by hand or with the aid of a great variety of mechanisms. One convenient form of apparatus for performing this function is shown in Fig. 1. It consists of upper and lower endless metal belts 10 and 11, respectively, supported on a suitable rolls with the lower reach of the upper belt running closely adjacent to but separated'from the upper reach of the lower belt. The carton blank 6 is fed between these belts where it will be gripped and can'ied along by them with the upper belt 10 bearing upon the reinforcing strip 2 which has just been applied to the carton. vLocated closely adjacent to this upper belt 10 are several electric heaters 12 which serve to heat the belt to such a temperature that I it will melt the adhesive 3 sufliciently to cause {while the adhesive is melted. A very secure union thus is produced between the backing strip. 2ofthetapeandthesurface ofthe carton. 'nie' eonveyingbeltsln andllshouldbemadeof .commercial taping and sealing machines.

such a length that a suitable time interval will be afforded to fuse the water resistant adhesive 3 securely to the carton. A substantial length of time is required for this purpose and this fact has been an important practical objection to the use of tapes coated with these adhesives in the The left-hand end, Fig. 1, of the conveyor belt 10 need v not be heated, or may even be cooled so as to reduce the temperature of the adhesive 3 sufficiently to make it set or harden before the carton blank is discharged at the end of the conveyor. Or, the carton may be delivered to a second conveyor like the conveyor 10-11 but having unheated belts which will perform this same function.

A very similar arrangement can also be used in connection with carton sealing machines for applying tape to the flaps of the carton to seal the carton. Usually, however, the backing for a sealing tape consists simply of a strong paper.

In Fig. 2 a carton which has been set up, filled and sealed is shown at 6'. The reenforcing tape applied in the mechanism shown in Fig. 1 is illustrated in Fig. 2 at 2' and the sealing tapes are shown at 2".

I have demonstrated "in practice that tapes of the character above described can be applied to cartons substantially as fast by this method as by the methods commonly used for applying tapes coated with a water soluble adhesive. In addition, the thorough heating of the tape in the conveyor belts is of advantage in drying out the water used in making the initial temporary bond between the tape and the carton so that when the cartons come out of the machine the reenforcing tape is thoroughly dried. This overcomes a disadvantage frequently experienced in using prior methods and in which the tapes come out of the sealing machine somewhat moist. The carton fiaps frequently are under considerable pressure at this time, and if the adhesive on the tape is still wet some slip frequently occurs between the tape and one or both of the carton flaps so that the carton will not be sealed tightly. In some cases the flaps even fly open. In either event hand taping usually is resorted to later to overcome this difliculty.

In making the tape shown in Fig. 3 the asphalt or other water resistant adhesive may be applied either in a melted condition-or, more preferably,

in the form of an emulsion. Emulsified asphalts are readily obtainable on the -market and the adhesive composition disclosed in the patent above designated can also be emulsified. These emulsions can be applied to the tape in the usual gumming machines and the necessity for installing an asphalt plant thus can be obviated.

If a clothtape is used, it is preferable to fill one side of the cloth with clay, talc or other suitable fillers in the manner disclosed in the Me- Laurin Patent No. 1,759,124, the other side of the cloth to which the adhesive is to be applied being left unfilled. This filler is useful in preventing the adhesive from sweating through the fabric when it is applied to the carton. A similar result can also be obtained by combining a. strip of paper with the fabric and then applying the asphalt or other water resistant adhesive to the surface of the paper. followed it is preferable to use a water resistant adhesive in performing the combining operation, although this is not absolutely necessasry for all uses When this process is of applying a superficial coating 4 of application are directed processof making it.

water soluble adhesive to the underlying coat of water resistant adhesive, as in the arrangement above described, the two adhesives can be mixed and applied in a single coat. This is very easily accomplished if the water resistant adhesive is used in the form of an emulsion. Any of the common glues, either fish or animal, or a mixture of the two, or vegetable gums which are soluble in water, can be mixed with the emulsion and thismixture applied to the tape in a common gumming machine. I have obtained entirely satisfactory results with a mixture of of water to apply the adhesive. For most purposes I consider this form of tape preferably to that previously described.

It is also contemplated that instead of using the more common water soluble adhesives for the outer coating 4 on the inner coating 3 of the adhesive, this outer coating may consist of an egg orblood albumen, or some equivalent substance which will give an initial tackiness sufficient to fasten the tape to the carton or other article of work and which will itself be rendered water resistant .by the subsequent heating step required to soften the coating of water resistant adhesive suificiently to cause it to bond to the carton. This has the advantage of substantially eliminating water soluble constituents from the final adhesive composition which is relied upon to bond the tape to the carton. At the same time it is open to the disadvantage of being more expensive and somewhatslower acting than the .forms of the invention previously described.

Tapes of the character here disclosed have the advantage not only of being highly resistant to the action of moisture and water, but, in addi tion, they are 'not likely to mold or to undergo the disintegration to which water'soluble adhesives frequently are subject when exposed to severe conditions. For these reasons they are particularly useful in connection with the packing of foods which must be stored in refrigerators or cold storage plants and they are usefulgin boxes of the set-up type as well as in cartons.

The method provided by'this invention makes it practical for the first time, so far as 1am aware, to use tapes coated with water resistant meltable adhesives inreenforcing, staying and sealing machines at speeds satisfactory to the trade;

It will be understood that while I have explained the process or method provided-by this invention in connection with certain apparatus, theme of this apparatus is not essential to the successful practice of the methodor process, but

that the method can be practiced by hand or with the aid of agreat variety of mechanisms.

This applicationis a division of my pending application Serial No. 531,052, filed -Aprll 18,

1931. The claims made in this application are confined to the method of applying the-tape or equivalent sheet material to cartons, packages, and the like, while' all the claims inthe parent to the tape and the Having thus described my invention, what I desire to claim as new is:

1. That improvement in methods of applying sheet material to an article of work which consists in producing a temporary attachment of the sheet material to said article by means of a water soluble adhesive, and subsequently fusing a water resistant adhesive. between said material and the work and thereby bonding the material securely to the work.

2. That improvement in methods of applying sheet material to an article of work which consists in interposing both a water soluble adhesive and a water resistant adhesive between said material and the work, moistening the water soluble adhesive prior to so interposing it, pressing the moistened adhesive surface against the work, and thereby producing an initial bond between said material and the work, subsequently melting said water resistant adhesive, and pressing said material against the work while the latter adhesive is melted and thereby producing a more secure union between said material and the work.

3. That improvement in methods of applying tapes to articles of work, such as cartons, which consists in producing an initial attachment of the tape to the article by means of a water soluble adhesive, and subsequently uniting said tape to the article by means of a. water resistant adhesive interposed between said tape and the article. 4. That improvement in methods of applying tapes to articles of Work, such as cartons, which consists in producing an initial attachment of I the tape to the article by means of a water soluble adhesive, and subsequently uniting said tape to the article by means of a water resistant adhesive.

which is not substantiallysticky at normal't'emperatures but which is adapted to become sticky when heated to temperatures substantially above normal.

5. That improvement in methods of applying tapes to articles of work, such as cartons, which consists in producing an initial attachment of the tape to the article by means of a water soluble adhesive, and subsequently uniting said tape to said article by fusing a waterproof adhesive between the tape and the article.

6. That improvement in methods of applying tapes to articles of work, such as cartons, which consists in producing a temporary adhesive union between the tape and article by means of a water soluble adhesive, and subsequently producing a more permanent unionbetween said tape and article with a water resistant adhesive.

7. That improvement in methods of applying tapes to articles of work, such as cartons, which consists in interposing both a water soluble adhesive and a water resistant adhesive between the tape and the article, utilizing said water soluble adhesive to produce an initial union between the tape and said article and-subsequently fusing said water resistant adhesive and thereby producing a more secure union between said tape and article.

8. That improvement in methods of applying a,

tape coated with a normally non-tacky water resistant adhesive to a carton or the like, which consists in producing a. temporary attachment of the tape to the carton independently of said-adhesive, subsequently softening said adhesive and PM the a againstthe carton while" s i adhesive is softened.

9. .That improvement in methods of applying a .tape coated with a normally non-tacky water resistant adhesive to a. carton or. the like, which "consists in fastening said tape temporarily tothe 15o sistant adhesive to a carton or the like, which consists in producing a temporary attachment of the tape to the carton with a water soluble adhesive, subsequently melting said adhesive, and pressing the tape against the carton while the adhesive is so melted.

WILLIAM W. MCLAURIN.

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