Abstract:
The present invention relates to a method for producing a squeeze tube with maximal surface area labeling and a tube produced thereby.

Description:
INTRODUCTION  
       [0001]     This application is a continuation-in-part of U.S. Ser. No. 11/251,033 filed Oct. 14, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Various products such as personal care or cosmetic products (e.g., toothpaste and lotions) are sold to consumers in flexible plastic tubes. Squeezable tube-shaped containers have a tubular body with one end heat-sealed along a straight line seam. For instance, see U.S. Pat. Nos. 5,632,951; 3,197,532; 5,908,124; and 5,213,235, which disclose the use of blow molding techniques for forming tube-shaped containers. In addition, U.S. Pat. No. 5,908,124 discloses the formation of an integral twist-off closure to eliminate the need for providing a separately manufactured closure. Also see U.S. Pat. No. 4,540,542 which discloses a method of making an extrusion blow molded container with an integral, removable closure and U.S. Pat. No. 5,141,136 which discloses a squeeze bottle having dual openings. The formation of tubular containers from a longitudinally stretched, extruded, thermoplastic cylinder is described in U.S. Pat. No. 3,047,910 and U.S. Pat. No. 5,069,856. Side-seam tubes are also generally disclosed in U.S. Pat. Nos. 3,959,066 and 4,310,369.  
         [0003]     Generally, the squeeze tube is formed by cross-sealing the tubular body with a cross-sealing apparatus. There are various techniques for sealing including hot jaw sealing, wherein the tube is pressed between a pair of heated sealing jaws; sonic welding; induction sealing where a magnetic field is used to excite foil within the tube wall structure to melt the plastic before pressing together; hot air sealing, wherein heated air is used to melt the plastic before pressing; and laser sealing where a laser is used to heat the plastic before pressing. In most cases, the tube is not labeled or decorated in the seal area because damage to the label, ink, or surface coating can occur during sealing. The label or coating can discolor due to the heat, or the label coating or ink may lose adhesion to the tube and separate due to the heat. In addition the application of label material, coating or ink on the surface of the tube in the seal area may affect the seal integrity or contaminate the inside of the seal area and prevent sealing. For these reasons the tube label and decoration generally does not cover the entire surface area of the tube.  
         [0004]     While Norden AndBro Inc. teach a medium density polyethylene tube with a full wrap label from Impres Label, which extends through the tube&#39;s sealed end, the label on this tube delaminates in the sealed area and is not esthetically pleasing when displayed on store shelves. As such, label manufacturers, such as FASSON Role North America (Painesville, Ohio), generally recommend that a label&#39;s edge be positioned on a tube at least ¼ inch from the start of the crimp to avoid subsequent label darting or flagging.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention relates to methods for producing a squeeze tube with maximal surface area labeling. In one embodiment, a label is adhered to a preformed tube and the label and preformed tube are sealed through so that a squeeze tube is formed, wherein the label encompasses at least a portion of the sealed area of the squeeze tube.  
         [0006]     In another embodiment, a label is adhered to a tube film, a tube is generated, and the label and tube are sealed through so that a squeeze tube is formed, wherein the label encompasses at least a portion of the sealed area of the squeeze tube.  
         [0007]     Squeeze tubes produced by the instant methods are also provided. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0008]     It has now been found that the labeled surface area of a squeeze tube can be maximized by extending the label into the sealed area of the squeeze tube. Advantageously, a label adhered to a tube or tube film in accordance with the disclosed method does not dart or flag and does not delaminate from the tube. As used in the context of the instant invention, a squeeze tube is a flexible, cylindrical package generally made from plastic (e.g., low to high density polyethylene, polypropylene, polyvinyl chloride, and softouch, dual layer, and coextruded plastics) or laminate film (ethylene vinyl alcohol resin). Squeeze tubes are formed by blow-molding or extruding material into a tube structure or alternatively rolling and adhering tube film (e.g., monolayer, coextruded or laminate film or sheet stock) into a side-seam tube structure. The tube thus formed is then filled through the open end with a machine designed for filling tubes. Subsequently, the filled tube is sealed at one end resulting in a package with a cylindrical, open end and a flattened, closed end. Accordingly, as one of skill in the art can appreciate, a label of the present invention can be applied to either a preformed tube (e.g., blow-molded or extruded), or alternatively applied to a tube film prior to generating the tube structure and end sealing.  
         [0009]     For the purposes of the instant invention, a tube or tube film used in the manufacture of a tube can be coated or uncoated prior to label adhesion. Coated tube or tube film is intended to mean a material used in the manufacture of a squeeze tube in which a surface coating has been applied. Such_surface coatings include any solvent-based, water-based or radiation-curable coating material designed to provide abrasion resistance, barrier properties and optionally enhanced gloss or matte finish. Such surface coatings include epoxies, urethanes, polyesters, acrylics, and the like. Conversely, uncoated tube or tube film is intended to mean a tube material which lacks a surface coating. Unexpectedly, it has been found that the label, when applied through the sealed area of the tube, achieves a comparable level of barrier properties as a coating. Because coating the tube or tube film could inhibit subsequent treatment to achieve a sufficient dyne level, particular embodiments embrace a tube or tube film lacking a surface coating.  
         [0010]     The methods of the instant invention can be carried out with a variety of tube materials in combination with a variety of label adhesives. As such, solvent-type adhesives, emulsion-type adhesives or hot-melt type adhesives are suitable so long as the adhesive selected can withstand the heat and pressure of end sealing. Such adhesives include, for example, rubbery adhesive agents, vinyl acetate adhesive agents, ethylene-vinyl acetate adhesive agents, polyvinyl alcohol adhesive agents, polyvinyl acetal adhesive agents, vinyl chloride adhesive agents, acrylic adhesive agents, polyamide adhesive agents, polyethylene adhesive agents, cellulose adhesive agents, polysulfide adhesive agents and hot-melt type high-polymer-containing adhesives. Other methods which promote label adhesion, e.g., a super adhesive, a coating, or other treatment that increases surface energy can also be employed.  
         [0011]     The term label is used herein in a broad sense to refer to a substrate that has been printed and subsequently attached to a surface so as to decorate the object or identify its contents. Labels, as used herein, can be supplied in various forms. Such labels can be individually cut and applied, can be cut, carried on and applied from a web of liner material, or can be unsupported, printed film or sheet roll stock that is subsequently laminated to tubes or tube film. Labels of the instant invention are affixed to the surface of a tube or tube film (i.e., the labels are not initially a component of the tube material itself) to provide product identifiers, product source/manufacturer identifiers, bar codes, nutritional information, decoration, and the like. Labels can be made of single or multiple layers and panels of any suitable paper or plastic material commonly employed in the labeling of consumer products. Advantageously, a label of the instant squeeze tube covers at least a portion, e.g., 20%, 40%, 50%, 60%, 80%, or 100% of the flattened, closed end of the squeeze tube, also referred to herein as the sealed area of the squeeze tube. As such, more surface area of the consumer package is available for providing product information or decoration.  
         [0012]     To facilitate adhesion, particular embodiments of the present invention embrace pretreating the unlabeled tube material under conditions which achieve a dyne level of at least 34. In other embodiments, a dyne level of 38 to 48, or more is achieved. Such conditions include treating the tube material with flame, plasma, or corona to enhance label adhesion. For example, corona treating involves discharging up to about 10,000 volts of electricity from a ceramic electrode to a ground roll over which the tube material is passing. This high voltage field called corona alters the surface of the film, raising the surface energy of the film so that label adhesion is enhanced. While a dyne level of at least 34 is desirable, it is contemplated that some tube materials could be used at a dyne level of 30 or 32. Surface tension or dyne level can be tested using any standard methods, e.g., dyne solutions or ACCU DYNE TEST™ marker pens.  
         [0013]     Because the label of the instant squeeze tube encompasses at least a portion of the seal area of the squeeze tube, particular embodiments of the instant invention embrace the use of a tube filling and sealing machine which seals through the label and tube by heating the internal surface of the tube so that the label is exposed to minimal heat during sealing. Suitable sealing techniques which heat the internal tube sealing surface before applying sealing pressure include hot air sealing, sonic welding, laser, and induction. Machines of this type are routinely used in the art of squeeze tube, bag and pouch manufacturing.  
         [0014]     A label affixed to a squeeze tube in accordance with the instant method generally has label peel strength adhesion values in the range of 1000 to 2500 grams/inch at 12 inches/minute pull speed. Optionally, label peel strength adhesion values in the range of 600 to 1200 grams/inch or 800 to 1500 grams/inch are also satisfactory under particular conditions. As such, particular embodiments embrace a label which does not subsequently delaminate in the sealed area of the labeled tube.  
         [0015]     Moreover, the label as affixed herein can be designed to withstand testing that would simulate normal use of the squeeze tube including, but not limited to, the moisture resistance testing, filled and unfilled; oven temperature storage at 45° C., filled and unfilled; product resistance; water submersion; soapy water testing; eight weeks-long term storage at 45° C.; and flexing.  
         [0016]     The instant method finds application in the manufacture of squeeze tubes for a variety of consumable or purchased goods or products including personal care products (e.g., soaps, shampoos, make-up, insect repellents, and the like); first aid products (e.g., ointments, sunscreens, and the like); cleaners (e.g., detergents and cleaning solutions); paints; and foodstuffs (e.g., yogurt, cheese-like products, jelly, and the like). The instant method is a significant improvement in the manufacture of squeeze tubes because the product label can encompass nearly all of the available surface area of the squeeze tube thereby enhancing the package appearance.