JPH08324893A - Core made of paper for thin film that is rolled and method of making this - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a tube capable of forming a core of a roll of a film, foil or the like. SOLUTION: A meltable material is extruded onto a paper sheet. The paper sheet is then cut into ribbons. A plurality of uncoated paper ribbons are wound to form the inner plies 12 of a tube. The coated ribbons are then wound about the plies formed by the uncoated ribbons to form the outer plies 18 of the tube. The entire tube is heat treated to melt the outer coating. A film is affixed on a paperboard tube and wound thereabout so that the tube 12 forms a core of a roll.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for forming a core around which a thin film is wound, and more specifically,
Forming the core as a paperboard cylinder.

[0002]

BACKGROUND OF THE INVENTION It has been known in the past to make paperboard cylinders that form the core of a roll of film, such as synthetic resin wrap, foil, etc., using sturdy paper laminate sheets. However, when the film is wound, the discontinuities on the surface of the tube make the impression of the film and each layer of the film simply
Because of the foundation of the discontinuity, the film is amplified as each layer of film wrapped around the tube. Therefore, it is desirable to have an outer surface that is as smooth as possible. Conventionally, it is known to wind a paper ribbon around a mandrel to form a tube with spirally stacked layers. The layers of ribbon are laminated together. One source of discontinuity on the surface of the tubular core is where the edges of the two ribbons abut each other to create a seam in each layer of the paperboard tube. It is known in the prior art to remove seam discontinuities by skiving. Skiving finish is the scraping of the edges of the top ribbon layer to remove such discontinuities. Further lubrication improvements have been made by impregnating the outer layer with a thermosetting resin. The impregnated cylinder is pushed through the heating die to reduce the outer diameter of the cylinder and cure the resin. The most common resin is a phenolic resin that hardens around the barrel creating a stiff outer surface. It is made even smoother by sanding the outer surface.

In order to make the cylinder ready for use by the manufacturer, sometimes a layer of tape is placed on the cylinder,
Attach the film to the tube so that it will be the starting point for winding the film around the tube. This tube forms the core of the overall roll. This conventional method has been satisfactory. However, it has the disadvantage of being a very complex method which is sensitive to many variables such as die heat, the presence of humidity during resin conditioning and coating, and the size of the article. The outside diameter changes during processing due to the curing of the resin and the use of heat. Second, this method requires capital because it requires many materials such as resins, chemicals, heaters and dies. Furthermore, the resins and chemicals have to be mixed by a considerable technique. This difficulty makes it a costly method. Finally, the tape on the barrel creates a discontinuity on the surface of the barrel, which should be avoided during the whole process. Therefore, it is desirable to make a tubular paperboard core around which a discontinuous portion can be removed while simplifying the process and around which a thin film can be attached.

[0004]

SUMMARY OF THE INVENTION An uncoated chipboard is cut into multiple ribbons. It can be extruded, melted,
The paper web is also coated with a material capable of maintaining an electrostatic charge, and the paper web is cut into ribbons. The ribbon of uncoated chipboard is wrapped around the mandrel to form the inner layer of the wall of the tube. A coated paper ribbon is then wrapped around the inner layer to create the outer surface of the paperboard cylinder. The tube as a whole is treated to soften the coating of the outer layer and bond the layers with a seam created by the abutting edges of adjacent layers. This treatment is one of a variety of non-contact methods for modifying the surface of polymeric coatings. For example, corona discharge to polyethylene or polypropylene,
Alternatively, flame treatment of ethylene vinyl acetate hot melt coating. The coating layer is then electrostatically charged and the film is applied directly to the barrel by electrostatic attraction towards the barrel. The film is then wrapped around a tube.
It is an object of the present invention to provide an improved method of making a roll of film or foil around a tubular paperboard core.

Another object of the present invention is to provide a simple method of forming a paperboard core tube that can be used as a core. Another object of the present invention is to provide a paperboard core that further removes surface discontinuities without the need for chemical sanding or skiving. Another object of the present invention is to provide a paperboard core capable of supporting a roll of film without the need for tape or other adhesive. Other objects and advantages of the invention will in part be obvious and will in part be apparent from the detailed description. The invention therefore has one or more such process relationships in relation to some of the processes and to each other, and items having this characteristic, property, and elemental relationship are illustrated in the following detailed description, and The scope of the invention is indicated by the claims.

[0006]

To complete the understanding of the present invention, a detailed description is given below with reference to the accompanying drawings.
1 and 2, a roll of film formed around a paperboard core is shown generally at 10. The uncoated paper is cut into a plurality of ribbons wrapped around a mandrel.
The ribbon is wound to form 2 to 40 layers 12 forming the inner layers of the wall 14 of the paperboard tube 10. Seams are formed at the abutting edges of layer 12. A second group of ribbons is formed by coating a piece of paper with polypropylene or polyethylene by extrusion or other methods. The sheets are then divided into narrow ribbons, which are wrapped around a layer 12 by a mandrel to make the outer layer 18 of the tube 10 with the coating 20 on the outer surface. Further, the seam 16 formed between the contact edges of the outer layer 18 may be skived or sanded to remove the discontinuous portion. To further remove the discontinuities in the outer layer, the outer coating 20 softens and sticks to form the seam 16
The paperboard cylinder 10 is treated to remove any discontinuities formed by the.

In the preferred embodiment, the layers 12, 18 are
Is 0.009 inches (0.02 cm) to 0.040 inches (0.10 cm)
Having a thickness in the range of Wall 14 is 0.02 inches (0.05c
m) to 1 inch (2.54 cm) overall thickness. The inner diameter of wall 14 is in the range of 0.50 inches (1.27 cm) to 12 inches (30.48 cm), depending on the size and application of the tube.
This range is exemplary and in no way limiting. The coating 20, if made of polypropylene or polyethylene, can accept and retain electrostatic charges. Therefore, in the embodiment in which one roll of the synthetic resin film is supported by the cylinder 10, the outer layer 2 of the cylinder is used.
0 is electrostatically charged. The film 22 is attached to the paperboard cylinder 10 by attracting by electrostatic charge, and
Wound around, the tube 10 forms the core for the overall roll of film. By forming an outer layer of a paperboard cylinder consisting of a paper ribbon coated with a meltable extruded material, the seam is melted to smooth the outer layer to fill the discontinuity of the seam. It is possible to remove the discontinuities formed at the seams of the paperboard by heat treating the entire paperboard cylinder to join the edges of the paperboard. By utilizing an outer layer capable of holding an electrostatic charge, the synthetic resin film may be applied directly to the barrel by electrostatic attraction and does not require tape to remove additional sources of discontinuity. The above description is
It was related to a roll of film. However, the method of forming the tube itself can be applied equally to foils or other rolls, except for electrostatic charging.

It will thus be seen that, from what has become apparent from the above description, the above-mentioned objects are effectively achieved. Also, in practicing the above method without departing from the spirit and scope of the invention,
Also, since it is possible to change the above items,
It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not in a limiting sense. It is understood that the claims are intended to cover all the general and specific features of the invention described herein and all statements of the scope of the invention that may be said to be literally included. Should.

[Brief description of drawings]

FIG. 1 is a perspective view of a tubular paperboard core and a roll of film formed according to the present invention.

FIG. 2 is a partial cross-sectional view of a paperboard core.

[Explanation of symbols]

 10 Paperboard Tube 12 Inner Layer 18 Outer Layer 20 Outer Coating

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication B65H 75/50 7620-3F B65H 75/50

Claims (6)

[Claims] 1. A paperboard cylinder for supporting a roll of film having a wall formed as a plurality of paperboard layers, wherein at least an outer layer of said paperboard layer is coated.
A paperboard tube consisting of the coated paperboard layer being coated with an extrudable or meltable material. 2. The paperboard tube according to claim 1, wherein the coating is one of polypropylene and polyethylene. 3. The paperboard tube of claim 1, wherein the coating is electrostatically chargeable. 4. A method of forming a roll of film around a paperboard tube, comprising extruding a meltable coating on a piece of paper, and cutting the coated paper into a plurality of ribbons. Winding a ribbon of uncoated chipboard to form an inner layer of the paperboard cylinder; winding the coated ribbon of paper around the uncoated layer, outside the paperboard cylinder A method comprising the steps of forming layers, heat treating the entire tube to melt the coating, and fixing the film to the paperboard tube. 5. The method of claim 4, further comprising a coating that electrostatically charges the coating to secure the film to the paperboard tube. 6. The coating is polypropylene,
Polyethylene and hot melt ethylene vinyl acetate (E
The method of claim 4, which is any one of VA).