US1962660A - Carton and method of sealing it - Google Patents

Description

June 12, 1934. v c, KELLER I 1,962,660

CARTON AND METHOD OF SEALING IT Filed March 2:5, 1929 ASPHALT 0R BITUMEN ADHESIVE INVENTOR.

Maw azaww ATTORNEYS.

Patented June 12, 1934 UNITED STATES PATENT OFFICE Charles L. Keller, Cincinnati,

Ohio, assignor to The Richardson Company, Lockland, Ohio, a

corporation of Ohio Application March 23, 1929, Serial No. 349,477 4 Claims. (Cl. 9336) 5 proof and grease resistant. Inasmuch as it is not practical to coat cartons with these sub- If the portions were of comparatively large size, as for example the end sealing flaps of cartons, the appearance of the completed and sealed carton would be greatly impaired. A still greater objection to the use of the above methods is that extra machines and handling are required to remove parafl'in from flaps in more than one direction. Indeed, to date, no such machine is in general use.

It is an object of my invention to provide an adhesive which will adhere to a paraflined surface and consequently a method of gluing knock down carton blanks without the necessity of the provision of means for removing paraflin or wax from any portions thereof.

It is an object of my invention to provide a glued knock down carton blank in which the original waterand greaseproofness has been preserved and has notbeen impaired over any area by a method employed to remove paraflin or wax therefrom.

It is still'another object of my invention to provide a paraffined folding carton or other type of parafiined carton with sealing flaps, and a method of sealing such cartons after they have been filled, the method not involving the necesused as a seal, and consequently in part at least as an adhesive, particularly in making the wax wrappers mentioned above; but the binding effect of paraffin is too weak to permit the satisfactory manufacture of cartons by any such practice. The band of'adhesive along the glued flap in a carton blank is necessarily narrow and must be quite strong. While somewhat less difliculty might be experienced in sealing the end flaps of a carton with paraflin alone, nevertheless this has not been regarded as practicable in a carton structure which forms the sole container for the material being shipped. In all cases where paraflin has been used as a sealing medium, of which applicant has knowledge, sepbeen used over the cartons, and the wrappers themselves have been heat sealed with paraffin. These and other objects of my invention I accomplish by that certain process of which I shall now describe an exemplary embodiment.

In the drawing: Fig. 1 is a perspective view of a carton to which my invention isapplied; and Fig. 2 is a sectional perspective view of the same.

Broadly my invention comprises the provision of an adhesive which will adhere to a paraflined surface either by amalgamation with the paraffin or otherwise. An exemplary type of such an tice may be stronger, than the internal strength of the board itself. This bond may be of two kinds. The preferable one is where the hot asphalt fluxes with the parafiin and penetrates to the actual surface of the board, so that pressure on the gluing machine permits only a very thin layer of asphalt-paraffin flux to remain and yieldv a fiber -to fiber bond as strong or stronger than the paper itself. A less preferable,

but still practical, bond'results when a thicker layer of asphalt remains so that, although it may penetrate to the surface of the bond, a fracture of the bond results insplitting the asphalt itself.

If the adhesive is an asphaltic substance, it is used hot and it may be that beside the fiuxing action noted above, the hot application of bituminous substance tends in some measure to drive the paraffin into the board. It. is to be noted however, that whatever action occurs, over the surface upon which the paraffin has thus been treated, there lies a film of bituminous substance which is also waterproof and grease-resistant, so that the proofness of the board is in nowise impaired.

My invention is not however restricted to the use of asphalt, but embraces'any equivalent substance which has the characteristic of amalgamating with the paraflln which overlies the carton surface, and forming either by itself or with the paraffin, an adhesive layer of the required strength. It embraces an adhesive which has the characteristic of penetrating through the paraffin layer and fastening on to the surface of the material to be pasted. Its usefulness is not restricted to the gluing of paraflined cartons but has application wherever it is desired to stick together by adhesive action, two substances, at least one of which has previously been treated with parafiin or wax. Thus it has application to he manufacture of bags, pouches and all manner of containers for hygroscopic goods, or goods which it is desired to seal in shipment against the effects of moisture, gases, grease and the like.

In an exemplary practice under my invention I employ as an adhesive an asphalt with Ball and Ring melting point of 150 to 160 degrees F., penetration 100 grams, 5 seconds of around 20. This is an asphalt commonly usedfor saturating felt for felt base floor covering. I introduce this asphalt into the glue pot of a standard gluing machine, the glue pot, as in standard practice,

being equipped with heating means generally of electric character. I run my adhesive quite hot, say at 400-450 F. and I apply it to the cartons in the ordinary manner. Thus it will be seen that the practice of my invention makes no change excepting in the nature of the adhesive and in the temperature at which it is kept, over ordinary practices in the gluing of carton blanks to form knock down folding cartons; nor are any additions to the gluing machine required, such as means separately to remove from the surfaces to be glued, their coating of paraffin or wax. Some care has to be taken with myprocess to see that after the application of the bituminous adhesive to one surface, that surface is pressed into contact with the surface to which it is to be glued, before the adhesive has lost its tackiness; and it is usually advisable to employ some care in temperature control to prevent the dulling of the parafiin surfaces which fall adjacent in any. stage of the gluing operation tothe heated band of adhesive. It goes without saying that the amount of adhesive should. be conto 215 degrees P.

application of hot bitumen,

trolled, just as in ordinary giving, to the end that there may be no excesses to be squeezed out upon the carton surfaces. It is to be pointed out also that in some cases and with certain materials, I may use a solvent if desired in connection with my bituminous adhesive, and to the extent of the solvent used, dispense with the use of heat.

In these descriptions the term glu means the combining or pasting together of portions of paper or paper board cartons or containers with heat liquefiable orsoftenable adhesive material such as'asphalt, pitch, gums, resins, etc., and in the manner of and with the equipment ordinarily used for this purpose with water soluble adhesive such as animal or destrin glues and the like.

Other examples comprises the use at 400 degrees F. of an air blown asphalt of a 200 Ball and Ring melting point, penetration 7'? degrees F., 100 grams, 5 seconds of 20 to 25, made from Mexican or Mexican and Illinois crude; the use at 500 degrees F. of fatty acid pitch of Ball and Ring melting point 145 to 150 degrees F., penetration 77/100/5 of around 60; the use at 300 to 325 degrees F., of Montan wax; the use at 420 degrees F. of orange flake shellac; the use of Carnauba wax at 320 degrees F.; the use of sulphur at 265 degrees F.; the use at 300 degrees to 325 degrees F. of coal tar pitch with 160 to 1'10 degrees F. .Ball and Ring melting point; etc. The kind of bitumen to be used for paraflined cartons will vary with the purpose to which the carton is applied. An ice cream carton, for example, requires a type of bituminous adhesive that will not open upat cold or freezing temperatures; a butter carton will not be frozen nearly so stifi; a cheese container may or may not be subjected to very low temperatures; a coconut (shredded) carton never is frozen or chilled intentionally. Consequently, for those cartons never chilled nor frozen the 20 penetration steam refined asphalt or 25 penetration air blown asphalt will serve as an adhesive at room temperatures but will not hold a good bond at cold temperatures. For

the chilled cartons a fatty acid or stearine pitch will hold the bond at low temperatures, (if desired a flux of asphalt suitable bitumen can be used).

A typical soft fatty acid pitch is one with Ball and Ring melting point 130435 deg. F., penetration '77/100/5 of 68, 32/200/60 of 29, 115/50/5 and is quite soft.

In the sealing of cartons after filling, the practice of my invention will comprise the substitution of my type of adhesive for other types of adhesive, the application thereof by the same means as at present employed, and the control of temperature as outlined above in connection with the pasting of knock down carton forms.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:-

1. That process of forming and sealing cartons of paperboard having a surface layer of wax, which comprises superposing the parts thereof which are to be joined adhesively with mutually facing surfaces, at least one of which surfaces and stearine or other has the wax layer, and, without'previous removal of said wax, cementing said parts together by the miscible to, some extent at least with said wax,

permeating the wax surface layer, and having and thereby.

facing surfaces, at least one greater adhesive and cohesive properties said wax.

than

2. That process of forming or sealing cartons of paperboard having a surface layer of wax. which comprises superposing the parts thereof which are to be joined adhesively with mutually of which surfaces has the wax layer, and, without previous removal of said wax, cementing said parts together by the application of hot asphalt to said mutually facing surfaces.

3. A carton formed of paperboard having a surface layer of wax, at least two overlapping portions of the body of said carton with mu- I tualiy facing surfaces, at least one of which said paperboard.

' CHARLES L. KELLER.

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