Patent Publication Number: US-6210766-B1

Title: Holographic decorated tube package

Description:
FIELD OF THE INVENTION 
     This invention relates to a tubular container that has a holographic decorative layer as an integral part of the tube structure. More particularly, this invention relates to a laminate structure for a tubular container where the holographic film layer is a non-metallized layer and is adjacent an exterior layer of the tube laminate structure. 
     BACKGROUND OF THE INVENTION 
     Tube containers can be decorated in various ways depending on the structure of the tube container and how it is made. By decoration is meant all of the indicia that is placed on the tube. This includes brand names, designs and general information printing. Tube containers can be decorated before or after being fully formed. Laminate tubes can be decorated before the tube is fully formed. The webstock from which the body of a laminate tube is formed will be printed when in sheet form with this printed webstock then being formed into the tube body. This webstock can be printed on the exterior surface, or on an inner layer of the laminate. An inner layer such as a paper or film layer can be printed with the decoration. If the tube body is made by extrusion molding or by blow molding, it usually will be decorated after the tube body or tube has been made and prior to filling and sealing. In this latter instance, each tube is put onto a mandrel with the tube surface being printed by relative motion between the tube and a print surface. In such tubes the tube decoration is on the exterior surface. Any one of these techniques can be used to decorate conventional tube containers, such as those used for dentifrices, lotions, shampoos, ointments, hair dressing, foods and other products packaged in tubes. 
     A new type of decoration for a tube container is holographic decoration. Such a decoration cannot be printed onto the exterior surface of a formed tube. A tube construction technique that can be used for creating holographic effects is a laminate tube. However in use with laminate films there is a tendency for the holographic films to delaminate. One reason is that the traditional holographic films are metallized films. Such metallized holographic films, their structure and their manufacture are described in U.S. Pat. No. 5,200,253. However since in most laminate tubes there will be an overlap longitudinal seal, one edge of the laminate will potentially be exposed to the contents of the tube. This presents the problem of the tube contents reacting with the metal in the holographic film with a delamination of the film. Such a delamination in the area of the longitudinal seal will cause the longitudinal seal to weaken and in many instances to fail. 
     This problem is solved in the present tube containers since the holographic film will be a non-metallized holographic film. It usually will be a polyester film. Also since polyester films have low moisture barrier properties they will have to be used in the form of a laminate with another film providing the needed moisture barrier properties. Further since the holographic film will be a polyester film it has been found that it cannot be the outermost layer or innermost layer of the tube laminate structure. This is the case since in the construction of a laminate tube the innermost layer must be a layer that can be heat bonded or compression molded to the upper shoulder part of the tube, and heat bonded to the outer laminate layer in forming the longitudinal overlap seal to form the tube body. In the heat bonding of the shoulder to the tube body, the shoulder is made separately from the tube body and bonded by heat to the shoulder. The inner layer of the tube body is bonded to the shoulder. In compression molding of the shoulder to the tube body, the shoulder is formed onto the tube body. That is, it is simultaneously formed and bonded to the inner film layer of the tube body. The longitudinal overlap seal is produced by heat and pressure on the two overlapped edges of the laminate (edge of inner layer and edge of outer layer) to form the sheet webstock into the tube body. 
     Whether the shoulder is attached to the tube body by heat bonding or compression molding, and forming the longitudinal overlap seal by heat bonding, the innermost layer of the tube body must be of a plastic bondable to the tube shoulder, and to the outermost layer of the tube body. Since like plastics bond best to like plastics, the innermost layer of the webstock preferably should be the same as the shoulder and as the outermost layer of the tube body. Since the shoulders are usually made of a polyene polymer such as polyethylene, polypropylene, polybutene, polybutadiene or an ethylene-propylene copolymer, the innermost layer should likewise be a polyene, and preferably the same polyene. Consequently the preferred structure for the present laminate is a polyene layer bonded to each side of the polyester holographic film. Polyenes provide a good moisture barrier and bond well to the same or other polyenes. Such a structure will provide for a good bond to the shoulder, a strong longitudinal seal and a durable crimp seal at the bottom of the tube. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a tube that has holographic decoration. Such a tube will have a laminate structure tube body that is bonded to a shoulder by heat bonding or compression molding. The body of the tube will have a multilayer laminate structure of an outer polyene layer and at least one inner layer that is a non-metallized holographic film layer. There can, and usually will be one or more other inner layers. That is, there preferably at least will be an innermost polyene polymer moisture barrier layer, the holographic film layer and the outermost layer. There can be additional barrier layers such as an organic barrier layer. A polyene polymer is an alkene polymer such as polyethylene, polypropylene or ethylene-propylene copolymers. Suitable organic barrier layers are comprised of homopolymers and copolymers of vinyl alcohol and of vinyl acetates. These include ethylene vinyl alcohols and ethylene vinyl acetate. In addition, there can be film tie layers between a barrier layer and the holographic film layer and between the holographic film layer and the outermost layer, which usually is a polyene layer. There also can be tie layers between inner barrier layers when there is more than one inner barrier layer. As noted, the shoulder is bonded to the innermost layer. In a preferred embodiment the shoulder is comprised of a polyene and the innermost layer is a polyene. 
     The holographic film layer is a non-metallized film layer. This usually is a polyester such as polyethylene terephthalate or polyethylene naphthalate. The holographic effect is formed on the surface of the film through the use of various printing and embossing techniques. A metallized layer is not used. A metallized layer would have a tendency to delaminate along the longitudinal seam of the tube by reaction of the contents of the tube with the metal of the metallized. Such a delamination would cause the tube to fail along the longitudinal seam. 
     The net result is a tube that has a holographic decoration, the tube body via the innermost film layer is readily bondable to the shoulder, and the innermost layer also is readily bondable to the outermost layer. Further, the tube body is not susceptible to delamination at the longitudinal seal due to the fact that the holographic film is not a metallized film. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-section of the holographic laminate film. 
     FIG. 2 is a cross-section of the holographic laminate film of FIG. 1 showing adhesive tie layers. 
     FIG. 3 is an elevational view of a holographic tube showing the longitudinal seal. 
     FIG. 4 is a cross-sectional view of the overlap longitudinal seal on the tube body along line  4 — 4  of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention will be described in detail with reference to the preferred embodiment shown in the figures. In FIG. 1 the laminate  10  is comprised of outer layer  12 , a non-metallized holographic film layer  14 , first inner barrier layer  16 , and a second inner barrier layer  22 . The second inner barrier layer  22  must be bondable to the shoulder of a tube. It also must be readily bondable to the outer layer  12  since the longitudinal seal of the laminate tube usually is an overlap seal. In such a seal the inner layer of one edge of the laminate will overlap the outer layer of another edge of the laminate as is shown in FIG.  4 . This exposes an edge of the laminate to the contents of the tube. It is for this reason that the holographic layer is a non-metallized layer and is essentially non-reactive with the contents of the tube. In most instances the polymer of this outer layer  12  and the second inner barrier layer  22  will be a polyene such as polyethylene, polypropylene, polybutene, polybutadiene or ethylene-propylene copolymers. The holographic film layer  14  can be any plastic used to produce holographic films and usually will be a polyester. Suitable polyesters are polyethylene terephthalate and polyethylene naphthalate. Either inner barrier layer can be a moisture barrier layer or an organic barrier layer. Polyenes are suitable as moisture barrier layers. Useful polyenes as previously set out are polyethylene, polypropylene, polybutene, polybutadiene and ethylene-propylene copolymers. However, polyenes are not very effective organic barrier layers. Useful organic barrier films are homopolymers and copolymers of vinyl alcohol and vinyl acetate such as ethylene-vinyl alcohol and ethylene vinyl acetate. Preferably the outer layer  12  and the second inner layer  22  are of the same polymer. The various film layers can be bonded directly one to the other, or can be bonded indirectly through the use of tie layers. The use of tie layers to bond the film layers of the laminate is shown in FIG.  2 . Here outer layer  12  is bonded to holographic film layer  14  by tie layer  18 , the holographic film layer is bonded to the first inner barrier layer  16  through tie layer  20  and the second inner barrier layer  22  is bonded to the first inner barrier layer  16  through tie layer  24 . 
     The tie layers are comprised of good adhesives. Suitable tie layer polymers are acrylates such as ethyl methyl methacrylate polymers and ethylene acrylic acid polymers. 
     The laminate is produced in a continuous sheet with these layers. The holographic film layer will provide a background decoration. Conventional laminate forming equipment can be used. 
     FIG. 3 shows a completed tube  30 . This is comprised of tube body  32  and tube shoulder  34 . The tube shoulder has an externally threaded exit nozzle  36 . The tube body  32  is comprised of a laminate of the structure of FIG. 1 or FIG.  2 . There is a longitudinal overlap seam  40  extending from the shoulder  34  of the tube to the crimp seal  38 . The structure of this seal is shown in more detail in FIG.  4 . End  44  of the laminate overlaps end  42 . The second inner barrier film layer of end  44  bonds to outer film layer of end  42 . An overlap seal is preferred over an abutting seal, also known as a fin seal. This overlap seal is visually more acceptable and it precludes having the two edges of the laminate extending outwardly from the tube body. However a disadvantage is that the edge of the laminate is exposed to the contents of the tube. If the holographic layer film was a metallized film it is likely that the contents of the tube would react with the metal of the metallized layer with the result being the delamination of the laminate along the longitudinal overlap seal. 
     This invention provides a way for tubes to be produced with holographic decoration and to have a strong bond attachment to the shoulder and to have a strong longitudinal seal. There is produced an effective holographic decoration for tubes.