US2337981A

US2337981A - Method of coating fiber containers

Info

Publication number: US2337981A
Application number: US427036A
Authority: US
Inventors: Hans A Eggerss
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1942-01-16
Filing date: 1942-01-16
Publication date: 1943-12-28
Anticipated expiration: 1960-12-28

Description

2 Sheets-S he t 1 INVENTOR Q Hans A. Eggzrss.

Dec. 28, 1943. H. A. EGGERSS METHOD OF COATING FIBER CONTAINERS Filed Jan. 16, 1942 I P M ;TTORNEYS Dec. 28, 1943.

H. A. EGGERSS METHOD OF COATING-FIBER CONTAINERS 2 Sheets-Sheet 2 Filed Jan. 16, 1942 INVENTOR Hons A. Eggerss M FM A71'ORNEYS Patented nee. 28, 143

UNITED STATES PATENT OFFICE; f, i 2,337,981 p H I Mn'rnon or coa'rmo mun commas Hans A; Eggcrss, Van Wert, Ohio, assignor to Continental Can Company, Inc.; New York, N. Y., a corporation of New York Application January 16, leiaseri i'no. 427,036 (01. 111-95) 6 Claims. I

My invention relates to a method of coating fiber containers. It hasto do, more particularly,

with a method for providing a protective thermoplastic resin coating on the inside of fiber containers;

The cylindrical body of fiber containers which have wide commercial use is formed by convolutely or spirally winding heavy paper in overlapping layers on a mandrel, the layers being glued or otherwise secured together. It has been customary to provide a protecting liner for a cylindrical container t: this type. At present, one

method of fabricating a lined container is to pro vide an inner liner sheet which has been precoated with a thermoplastic resin. Obviously, whether this liner paper is applied lap or butt scam, the edge of the paper is exposed. It has been customary to seal this scam by'means of tape but usually this is the weakest point in the protecting seal of the container since the method of joining this' tape to the coating makes it weaker than theoriginal ,film, whether adhesive is used on-the tape or whether other methods are employed. Another method of producing a protecting' film on] the interior of a fiber container consists in coating "the inside of-the completed drum with a solution containing a suitable resin and then evaporating the solvent. This method does result in a coating over the seam of the liner paper, but entails all .the operations necessary to remove the solvent from the drum, which normally are difilcult operations, particularly if organic solvents are employed. Also in this latter-method of coating, it isdifficult to produce -an unbroken film since the exposed edge of the sheet acts like a wick and soaks up the coating material rather than allowing it to be deposited on'the surface.

One ofthe objects of my invention is to pro vide amethod 6; applying a film or coating on the interior of a fiber container after it has been formed and in such a manner that there will be no seam in the protective coating. v

Another object of my invention is to provide a method of applyi g a protective coating on the interior of a fiber container 1 that there will be no danger of the coating peel- Another object of my invention isto'provide a simple, effective and economical method for applying a-coating of thermoplastic resin to the interior surface of a fiber container.

In its preferred form my invention contemplates applying a continuous film without seams in such a manner moplastic material into the material of the container. In the case of a cylindrical container shell, the calendaring rolls will operate inside and outsideof the shell and will simultaneously produce relative rotation of the shell so that the entire surface thereof will be covered with a continuous film.

. In the accompanying drawings, I have illustrated one form of apparatus which may be used in performing my method. In these figures, similar characters of reference designate correspond- I ing parts, and

l Figure lis an end view of the apparatus showing a cylindrical container shell inposition. r Figure 2 is a front view of the apparatus with the container shell broken awa for clarity.

Figure 3 is a p p n V ew, partly broken away, of the apparatus.

. Figure 4 is a vertical sectional view takenthrough the calenderlng rolls and illustrating how Ethey act. so

the shell showing the coatingapplied to thein- Figure 5 is a perspective view oi the apparatus. Figure 6 is a perspective view of a portion of terior thereof. v

Figure '7 is a diagrammatic view illustrating the method where a mass of the thermoplastic material is employed.

' Figure 8 is a similar view showing how a sheet or stripof the thermoplastic resin may be employed.

With reference to the drawings, I have illustrated one form of calendering apparatus which may be employed with my process. However, it is to be understood that the form shownis merely one example and that the apparatus may take various forms.

The apparatus may constitute a base I having a cradle formed by rollers 2' adapted to support the cylindrical container shell S. The base I supports a standard 3 which supports on its upper end for rotation rolls l, .5 and 6.. The roll 6 is hinged to the standard at one end, as'indicated at I, so that it may be swung outwardly to permit positioning of the shellS between the

rolls

5 and 6. Suitable locking'means Bfjmay be provided at its opposite ends for, holding the roll 6 in its operative position. The

rolls

4 and 5 may be hollow and may be heated by centrally disposed steam pipes 9 and ID. The

rolls

4 and 5 may be driven by a set of'gears I! towards each other as indicated in Figure 5. It will be apparent that whenthe roll 5 is driven the shell S will rotate on its cradle and will be moved continuously between the

rolls

5 and 6 as illustrated in Figure 4.

The container may be formed of spirally wound will be produced. Since a thermoplastic resin is used, it will become sufficiently hard as soon end of the film "a has overlapped the other. However, there will be no Joint between the overlappingportions-because of the calenderirm operation. The film will be continuous as before.

It will be apparent from the above description.

that I have provided a method of applying a protective film or coating on the interior of a fiber container after the container has been formed in such a manner that there will be no seams in the protective coating. The coating is applied in such a manner that there will be no danger of it peeling. My method is simple, eifecas the shell of the container cools to the proper extent. Then the shell may be subjected to suitable operations to apply a bottom thereto. The thickness of thefilm may be varied by varying the time of calendering and the amount of pressure exerted by rolls 5 and 8.

The thermoplastic resin employed may be in powdered form which is placed together with a sufllcient amount of plasticizer into a heated mixer which thoroughly mixes the resin and plasticizer in a single semi-viscous mass. This mass could then be placed between heated malaxating rolls which would thoroughly mix the material and bring it up to the molten plastic consistency suitable for -use on the calendering rolls. This material may be placed directly on the rolls as shown in Figure '7. The material could then be calendered upon the container shell as a continuous film. Any temperature may be employed in the calendering operation which will render the film sufliciently plastic to be calendered. This temperature will depend upon the particular type of thermoplastic resin employed.

In Figure 8 I illustrate a modification of my 1 invention. In this instance thermoplastic resin in the form of a strip I5 is employed. This strip is passed between a heated calendering roll Ba and a pressure roll 8a. The continuous strip will be calendered onto the surface of the container as before. The strip I! may be out after one tive and economical to perform.

It is to be understood that although I describe my method as being employed for coating the interior of a fiber container. it may be used for coating the exterior surface thereof if desired.

Having thus described my invention, what I claim is: v

l. The method of applying a protective coating to the surface of a fiber container of cylindrical form which comprises rotating the container about its axis with. calendaring rolls operating on the interior and exterior surfaces thereof and applying a film of thermoplastic resin to one of said rolls which will transmit it to said surface.

2. The method of applying a protective coating to the surface of a fiber body of tubular form which comprises rotating the body about its axis while simultaneously calendaring a film of ti. ,-rmoplastic resin on said surface under. heat and pressure.

8. A method according to claim 2 wherein the film is applied to the inner surface of said body.

4. The method of applying a protective coating to the surface of a fiber body of tubular form which comprises rotating the body about its axis while simultaneously applying a film of thermoplastic resin on said surface underheat and pressure.

5. A method according to claim 4 wherein the film is applied to the inner surface of said body.

6. The method of applying a. protective coatingtothe interior surface of a tubular body having a seam extending longitudinally of said surface which comprises rotating. said body about its axis and simultaneously calendering a. continuous film on said inner surface and over said seam by means of heat and pressure.

HANS A. mamass.