System for reducing the release value of a label

A system for producing a roll of label material with a reduced release value. The system includes a separating apparatus configured to separate an initial label roll into two portions including an adhesive coated portion and a release agent coated portion. The system also includes an advancing apparatus configured to maintain the two separated portions apart and advance the portions toward a combining apparatus, which is configured to combine the two portions into a final label roll having a release value lower than the release value of the initial roll of label material.

The present application relates to adhesive labels and methods of manufacturing customized adhesive labels from a stock roll of label material.

BACKGROUND

Pressure sensitive labels are typically constructed with a base layer of linear material, a release agent, a layer of adhesive and the face stock material upon which is printed any desired information. Labels are converted and supplied to end users on rolls. During conversion, the rolls of labels are loaded into automatic label applicators, where they are threaded around rollers, through sensors, through printing devices to a peel edge (sometimes referred to as peel bar, peel plate, dispense edge, etc.). From the peel edge, the labels are removed and the base layer of linear material continues through a roller drive to a linear rewind. A label applicator is used to feed and dispense the labels. The label is applied to the product by pressing the label onto the product.

A common problem associated with label application relates to the way that labels dispense from the peel edge. Manufacturers of label applicators have provided many different features in the applicator machines in an effort to facilitate the release of the labels from the silicone coated base layer of linear material as the labels dispense off the peel edge. In order for a label applicator to work reliably the labels need to dispense consistently, preferable straight off the peel edge, as the label is typically being feed onto an application pad, before being applied to a product.

Some manufacturers produce machines that have very sharp peel edges in an attempt to ensure consistent separation of the label from the linear base layer. However, if the peel edge is too sharp it can tear the linear material. In another example, some applicator machines include spring pressure plates on top of the label to apply pressure and/or drag to the label before it is dispensed. Other applicator machines may include air jets to assist in directing the label off the linear material as needed. All of the aforementioned modifications to applicator machines require the operator to make critical adjustments to the equipment in order for the label to dispense consistently. As different rolls of labels are loaded in the automatic applicator machines, the operator is forced to adjust the machines accordingly, at times without success and, as a result, an entire roll of labels must be discarded, adding cost to the final product. Thus, there remains a need for a reliable and cost efficient way of ensuring consistent separation of the label from the layer of linear material.

DESCRIPTION

Various features of the present invention will be described with reference to the drawings. Like numbers are used throughout the drawings to refer to the same or similar parts and in each of the embodiments of the invention hereafter described.

As described herein, the invention is directed generally to a label that releases from the underling linear material consistently, while still maintaining excellent adhesion. For example, a roll of labels, with the label release force reduced, is configured to allow the labels to peel off the linear more consistently when dispensed via an automatic label applicator. The scope of the invention includes various arrangements of labels such as sheets or strips of labels. A sheet or strip of labels may be rolled for transport and use with convertor and applicator equipment, as described herein.

Rolls of labels are generally converted on high speed label presses. As shown inFIG. 7, a master roll30of label stock is converted into labels to be applied to a product. As shown inFIG. 2, the label stock material generally includes a base layer of linear material3(sometimes referred to as the carrier). The linear material may be paper, film or any medium suitable for supporting the label material. The linear material is covered with a release agent4, typically silicone. The release agent maybe sprayed onto or rolled onto the linear material. The release agent4is applied to prevent an adhesive2from sticking to the linear material3. The release agent forms a liner layer on the linear material.

The layer of adhesive2, which typically sprayed over the release agent4, may be a cold glue, a rubber glue, an acrylic glue or any suitable adhesive material. During assembly of the master roll of label materials, the label face stock material1is rolled on to the top of the adhesive2by passing the layers through a series of rollers, with varying degrees of pressure, varying ambient temperatures, varying humidity and then wound to form on a master roll.

As the master roll30is wound, it is not uncommon for the label face stock material located in the center of the roll to be connected to the base layer with more adhesive force due to the weight of the roll. At the outer regions of the master roll, the adhesive force may be reduced. Also, adhesive force may vary due to temperature and the uniformity of the adhesive layer. In addition, the master roll30is normally placed on a pallet20and is strapped down22and shipped to the converter. While on the pallet, the weight25of the rolled up roll30causes some variation in the adhesive force between the label stock and the linear material. The bottom of the roll has all the weight of the roll, while the top only carries the weight of a few layers of labels. The varying pressure associated with the weight may cause varying adhesive force between he label and the linear base layer. Thus, as a result of these and possibly other factors the adhesive force between the face stock1and the linear material3may vary throughout a roll.

As described below, the present application discloses a label material that provides for consistent release of the label from the linear base material. In general, the label is formed by separating the adhesive2and face stock1layers from the linear material3and release agent4. After separation, the layers are recombined in manner generating less and more consistent pressure. This innovative process produces a roll of labels that yields for an easier and more consistent release of the label from the linear material.

As shown inFIG. 1, according to an exemplary embodiment, a master roll of label stock30is loaded into a specially designed converting press37. The label stock30is threaded through the machine, when the stock material has reached the separating section of the converting press the label stock material30is separated into two sections. The converting press includes a separation apparatus that maintains a separation between the face stock1and adhesive material2from the linear material3and release agent4. The separation apparatus includes rollers40,41that carry each of the two separated portions away from the feeding stock material30. As shown inFIG. 1, the stock on a master roll is loaded onto the converting machine or press and threaded to rollers41,40. The separation occurs as the face stock1and adhesive material2travel around roller41and up to roller34, while the linear material3and release agent4travel around roller40and down to roller33, pulling the two materials apart.

The press also includes an advancing apparatus for carrying the separated face stock material1and the linear base material3through the press in a separated position. The advancing apparatus portion of the press includes at least a pair of rollers34,36for carrying the face stock material1and at least a pair of rollers33,32for carrying the linear material3. The advancing apparatus may also include an additional roller38for repositioning the linear material in a horizontal position in advance of entering a combining apparatus. The combining apparatus may include a pair of rollers31,36through which both the face stock material1and the linear material3are married back together. The rollers31,35may be pressure rollers that apply force to the label material. The amount of pressure applied can be varied by moving pressure roller36up or down to increase or reduce the amount of release tension or force required to separate the label from the linear material.

While the face stock is separated from the linear material, the amount of time the separation occurs can be varied. The spacing of the rollers32,33,34,36can be increased. The longer the rollers are separated the less tension between the adhesive and the silicone as the adhesive has been exposed to air and will begin to cure. To accelerate the drying of the adhesive a fan39and/or heater43can be use to blow hot air onto the adhesive2. In addition, the advancing speed of the material can be adjusted in order to reduce or increase the exposure time of the adhesive material2.

The label stock is then further processed in a conventional manner using a conventional processing machine or apparatus35. For example, in a manner well known to those of skill in the art of label converting, ink rollers and printing plates may be used to print images on the face stock. The face stock material may be die cut to produce individual labels56. The labels and linear base layer may be wound onto rolls52. The rolls of converted labels may be removed from the machine and packaged with the rolls (preferably with the rolls resting on their side) for shipment to the end user.

The end user, a label applicator, receives the labels. As can be seen inFIGS. 5 and 6, the rolls of labels are loaded onto a label applicator70. The labels are threaded through the label applicator around idle rollers51, through a gap sensor55, to the peel edge58. The label applicator may contain additional mechanisms not shown. At the peel edge58, the labels56and linear material60are separated. The linear material is threaded around a roller51back to the drive. The linear material also passes around a nip roller65and a drive roller64, and through to the take up roller63. When labels are to be dispensed, the nip roller is positioned against the linear material and the driver roller. When the drive roller64rotates, the linear material is pulled back through the machine, causing the labels56to be dispensed off the dispense edge and onto a tamp pad61. The tamp pad may include holes54through which a suction force is applied to hold the label onto the pad. The vacuum holes54may be dispersed across the pad. The tamp pad61may be extended (e.g., downwardly inFIGS. 5 and 6) in order to affix the label to a product. Movement of the tamp pad61may be accomplished by using a hydraulic piston/cylinder arrangement53or other suitable configuration.

FIG. 6shows the benefits of the exemplary embodiment described herein.FIG. 5shows a conventional label applicator having a spring tension plate59, pressing on the top of the label prior to it being dispensed. The applicator ofFIG. 6, may also include an air jet65, providing a stream of air to62to direct the label onto the tamp pad. The air jet65is used to prevent the label from not completely separating from the linear material and from starting to follow a similar path as the linear material.FIG. 3is an enlargement of the problem area57inFIG. 5.FIG. 3shows the label bending around the peel edge58in the direction of travel of the linear material60due to the relatively strong adhesive forces holding the label stock material and the adhesive to the linear material and the release material (e.g., silicone). The adhesive force can be quantified by testing and determining the release value of the label material.

The innovative system shown inFIG. 6, on the other hand, does not require the tension plate or jet of air. As shown inFIG. 6, the labels56consistently and easily release from the linear material60. As shown inFIG. 4, after process according to the exemplary embodiment described above, the labels dispense flat and smoothly off the linear material at the peel edge.

FIG. 8discloses a chart of 25 conventional labels removed from a linear material using a release testing machine to measure the release value. The average release value is 26.8 grams with a standard deviation of 5.6 grams. The release value testing procedure is a standard testing procedure published by the Tag and Label Manufactures Institute (TLMI). The release testing is performed using a common Adhesion/Release testing machine, such as model AR-1000 manufactured by ChemInstruments of Fairfield, Ohio, testing to meet ASTM: D 3330 standard.FIG. 9is a chart of the results of the measured release value of 25 labels using the same release test machine. The labels used for the testing shown inFIG. 9, are labels formed using the process described herein. The average release valve is 19.8 with a standard deviation of 3.3. Thus, as described herein, the label material formed using the separation and recombining process described above, reduces the adhesive force5between the adhesive material2and silicone3by 35%, and results in a consistent overall improvement of the release force of approximately 70%. The improvement is measured by the improvement in the ability for the two layers to separate on an automated high speed label applicator. For those skilled in the art of label applicator manufacturing, this would significantly improve the performance of the machines.

References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” “fore,” “aft,” “inboard,” “outboard,” etc.) are merely used to describe the orientation of various elements in the figures. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.