MXPA98007605A - Transfer label that has ink containment layers, container that comprises a transfer layer and method to wash such recipie - Google Patents

Abstract

The present invention relates to a transfer label comprising a reinfng layer and a transfer layer, which is freely coupled to the reinfment layer. The transfer layer comprises an ink layer and on each side of the ink layer a top containment layer and a bottom containment layer. The upper containment layer and the upper containment layer contact one another outside the perimeter of the ink layer to form a closed envelope around the ink layer. The transfer label according to the present invention can be applied to a container such as a box, and can be easily removed therefrom in a washing process without the ink dissolving in the lava liquid.

Description

TRANSFER LABEL THAT HAS LAYERS OF INK CONTAINMENT, RECIPIENT COMPRISING A TRANSFER LAYER AND METHOD TO WASH SUCH CONTAINER BACKGROUND OF THE INVENTION The invention relates to a transfer label comprising a reinforcing layer and a transfer layer, which is releasably coupled to the reinforcement layer, the transfer layer comprises an ink layer. The invention also relates to a container provided with a transfer layer according to the invention, and to a method for removing or removing the transfer layer from such a container. It is known in packaging technology to label containers such as plastic boxes by providing a permanent non-removable image by a mesh screen method. Such labels offer a highly durable finish with availability of two or three colors. This technique however offers limited colors, lacks the improved graphic features offered by other labeling techniques, is not flexible in REF. 28452 its ability to have graphical changes, to meet market strategies leading to large inventories of obsolete units, and tends to show signs of wear after approximately four journeys. When removable parts are to be applied to reusable plastic boxes by a stencil printing process or a tampon printing, the inks have to be applied in the bottling plant, such as a brewery, which can lead to problems with regarding the registration. After the removal from the boxes by means of box washers, the inks will be dissolved in the washing liquid and in this way will contaminate the box washers. In addition, the speed of application is limited, and the curing of the inks requires a lot of space and long storage times before distribution. A second way to label the containers involves gluing printed paper labels to the containers, such as plastic boxes or bottles at the time of filling and sealing. Such labels, however, offer little resistance to label damage from handling and exposure to moisture (wrinkling). In addition, Paper labels are difficult to remove from boxes and tend to clog the box scrubbers available today. After the removal of the paper labels from the plastic boxes, a residue of glue or glues may be left on the boxes. A third technique for labeling the containers, in particular glass bottles, is based on the principles described in International Patent WO 90/05088. In this publication, we describe a method for labeling bottles which provides a highly impact resistant, durable label, and still allows high definition label printing. A transfer label comprising a removable backing layer is provided, the backing layer of which is reverse printed with a vinyl or acrylic ink which is cured and overprinted with adhesive. The label is applied to the container with its adhesive surface in contact with it. The reinforcing layer is separated from the label transfer layer for example by the application of heat to either the container, the label or both. The labeled container is then applied with a coating which is subsequently cured. He Curing coating provides the required degree of impact resistance and durability. The disadvantage of permanently coupled labels is that when these labels become scratched or otherwise damaged, they can not be easily removed from the bottles. Also, it is not possible to provide the same containers each time with new and / or different labels, which is desirable for promotional activities. An object of the present invention is to provide a transfer layer which can be easily coupled to a container, and which can be removed in an environmentally friendly way. A further objective of the present invention is to provide such a transfer label, which can be removed in a washing process using a washing liquid, without the inks of the label that contaminate the washing liquid. A further object of the present invention is to provide a transfer label having an adhesion during storage and use of the container, but which can be very quickly removed from the container, an inexpensive way to replace the label with a new and / or different label. Still another object of the present invention is to provide a label that uses water soluble inks as a printing substance, such inks being environmentally friendly and widely used in food technology. Still another objective of the present invention is to provide a system of returnable boxes that can be provided with attractive labels, which can be easily and economically removed and reapplied. The labels must be applied and removed at relatively high speeds.

BRIEF DESCRIPTION OF THE INVENTION For this, the label "transfer according to the present invention is characterized in that the transfer layer comprises on each side of the ink layer a top and bottom containment layer, respectively, the top and bottom containment layer, make contact one with the other outside the perimeter of the ink layer, to form a closed envelope around the ink layer.

By trapping the ink in the envelope between the containment layers, it is possible to remove the transfer layer from the container it has been attached to, by a wet removal process such as a soaking process or a process using jets of high pressure water. It is prevented that the ink leaks from the envelope during such process, so that contamination of the wash water does not occur. During the wet removal process, no more than 10% by weight of the ink in a transfer layer is dissolved in an alkaline washing solution. This prevents containers from being discolored by the inks. In addition, the levels of the ink in the wash solution remain sufficiently low so as not to affect the aerobic and anaerobic treatment in the waste water treatment plants. The low concentrations of inks in the wash water prevent the accumulation of metals in the sludge from wastewater treatment plants, such that this sludge will not have to be treated as chemical waste under government regulations. Simply by collecting the labels removed from the washing liquid, a very economical washing process can be achieved.

Preferably, the ink layer comprises separate areas of dimensions between 0.5 mm2 and 500 cm ", the upper containment layer and the lower containment layer make contact with each other outside the separated zones, to form individual envelopes around each zone The areas of the transfer layer that connect the separated areas of the ink layer will have a reduced thickness compared to the areas where an ink layer is present between the containment layers. the transfer layer to a container, it is possible that no label material is present outside the separate ink zones.These areas of reduced thickness or open areas of the labels, outside the wraps, form natural points of attack for the solution of washing, such that the label can be removed in separate parts, because the washing solution has access to the label-container interface per m From the areas outside the wrappings around the printing patterns, a very rapid removal of the transfer layer from the container is possible, whereby the label is removed in separate pieces. These pieces can be sifted from the solution of washing using conventional sieves with openings having a size between 0.1 mm and 10 mm, preferably about 2 mm. Although it is preferred to use the transfer layer according to the present invention on reusable plastic boxes, the label can also be used in combination with plastic bottles, such as PET-type bottles, plastic food trays, glass bottles and the like. A preferred transfer label according to the present invention comprises a transfer layer which is permeable for soaking liquids. By "permeable" is meant that a transfer layer has a water uptake value after 3 hours between 0.0 and 100 g / m2, preferably about 5"g / m2, in water at room temperature. water vapor transmission between 50 and 750 g / m2, preferably approximately 600 g / m2 after 24 hours for water at room temperature.The transfer layer can comprise a layer that covers the ink pattern, whose cover layer forms the surface facing outwardafter the coupling of the transfer layer to a container. The cover layer can be formed, for example, by an acrylic wax coating. The cover layer can be a continuous layer, or it can be discontinuous and printed to register with the ink pattern. The acrylic wax covering layer can be very advantageously penetrated for example by a 0.5% sodium hydroxide solution, while providing a sufficient barrier for the penetration of moisture during storage conditions and use of the label on a container. Labels according to the present invention, which combine sufficient durability with fast and economical removal have a pencil hardness between IN and 7N in the dry spade, and a pencil hardness less than 0.5 N after a soaking time between 1 minute and 15 minutes in water at 20 ° C. Preferably, the transfer layer has such a configuration that it is broken into at least four pieces under conditions of turbulent soaking in an aqueous solution of a temperature below 100 ° C, preferably below 70 ° C within a certain time. Soak no more than 20 minutes, preferably no more than 10 seconds. According to the Transfer layer is uncoupled from the container, the size of most of the pieces formed after the breaking of the transfer layer, is preferably not smaller than the dimensions of the areas separated from the ink pattern. Although some of the wraps may break during the washing process, this causes relatively little leakage of the ink contained within the wraps, since these inks will still be surrounded by a substantial portion of the containment layers. Water-soluble inks can be used by using the containment layers according to the present invention. In a preferred embodiment, the topmost containment layer comprises a non-pigmented ink which is compatible with the underlying printed area. The lower containment layer preferably comprises an adhesive layer or an intermediate layer which is compatible with an underlying adhesive layer, and with the layer of the ink zone located above. The upper containment layer can be discontinuous and printed to register with the ink pattern. In this way the lower containment layer can be directly attacked by the liquid from washing during the removal of the transfer layer. When the lower containment layer is also discontinuous, the underlying adhesive layer can be directly attacked by the washing liquid. In a preferred embodiment both containment layers and an underlying adhesive layer are discontinuous and all printed to register. After application of the transfer layer to the container, a cover layer may be applied through the transfer layer, the cover layer comprising an acrylic wax. The acrylic wax is relatively impervious to water, such that a good resistance of the label against scratching and the removal of the label during use is provided. The acrylic wax covering layer however is permeable to an aqueous alkaline solution, such that the transfer layer can be easily removed for example by a 0.5% sodium hydroxide solution. Preferably, the transfer layer is heat treated after it has been applied to a container, to cause a shrinkage of at least parts of the transfer layer. Through the heat treatment, a coalescence of the different layers of the transfer label. A label according to the present invention which combines sufficient durability during storage and use, with rapid and economical removal, has been preferably heat treated after application to the container at a temperature between 40 ° C and 100 ° C, more preferably between 50 ° C and 90 ° C. By carefully selecting the composition of the label, the use of a protective coating and the nature of the post-treatment (heat treatment) it is possible to direct the properties of the transfer layer, especially with respect to the behavior during washing. The selection of the adhesive to be used in the adherence of the image of the label to the surface of the label will influence the properties of the wash. The adhesive must have been activated before or during the application of the transfer layer to the container. An easy and generally preferred method of application to the image is through the use of heat activatable adhesives that have been applied to the image in the form of an inverted printed label. Others Methods include the use of adhesive that can be activated through radiation, chemicals, electron beam, microwave, UV and the like. It is also possible to use adhesives that can be activated through photoinitiation, moisture, enzymatic action, pressure or ultrasonic treatment. A preferred adhesive has a low tack or tack temperature, preferably between 60 ° and 90 °, more preferably between 80 ° and 90 °. Instead of a separate layer of adhesive, it is also possible to use an ink in the transfer layer that itself has adhesive properties after activation. Preferably, the application surface of the container for receiving the transfer layer has a surface tension of at least 60 dynes per cm. The method of washing a container comprising a transfer layer according to the present invention, comprises the steps of: placing the container in a soaking solution during a soaking time not greater than 20 minutes, preferably not greater than 1 minute, the temperature of the soaking solution being below 100 ° C, preferably below 70 ° C, at the same time that turbulence is caused in the soaking solution such that the label breaks into at least 4 parts, each part being not less than 5 micrometers and is decoupled from the container, most of the ink remains contained within the wraps, the pumping the soaking solution through a sieve and collecting the pieces of the label on the sieve, periodically cleaning the sieve by collecting and removing the label pieces. A transfer layer according to the present invention can be removed using conventional box washing equipment, wherein the coupled label pieces can be removed from the soaking solution by means of sieving. Since no part of the label dissolves in the soaking solution, no specific treatment equipment needs to be employed for the cleaning of the washing solution. 1 BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of a transfer layer and a washing method according to the present invention will be described hereinafter in detail, with reference to the accompanying drawings. In the drawings: Figure 1 shows a thermal transfer label according to the invention, wherein the separated ink patterns are each contained in a single envelope, Figure 2 shows a washing device for the removal of a transfer layer according to the present invention from a container, in particular from a plastic box.

Figure 3 shows a cross-sectional view of the washing device according to Figure 2, along the line III-III.

Figures 4-7 show various modalities of the transfer layer of a transfer label according to the present invention.

Figure 8 schematically shows a plan view of a modality of a transfer label according to the invention, comprising wraps of different sizes around the ink pattern, Figure 9 schematically shows a method for applying the transfer layer according to the present invention to a returnable box, and Figures 10 and 11 graphically show the removal time of a transfer layer at different post-heating temperatures, without a wax cover layer and with a wax cover layer, respectively.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows an embodiment of a transfer tag 1 according to the present invention, comprising a carrier, or layer of reinforcement 2 formed for example by a 50 micron (2 mil) thick polypropylene film. A layer of silicone 3 is located on the carrier or reinforcement layer 2. On the silicone layer 3 is placed a transfer layer 4 consisting of a top containment layer., 5 ', an ink layer 7, 7', a lower containment layer 6, 6 'and an adhesive layer 8, 8'. After the coupling of the transfer layer 4 to the container, the carrier layer 2 and the silicone layer 3 are removed under application of heat and pressure. The adhesive layer 8 connects the transfer layer 4 to an underlying surface of the container, and the outward facing layer is formed by the upper containment layer 5, 5 '. The label carrier 2 which is provided with the silicone layer 3"cured by electron beam, can be for example a polypropylene film of 25.4 to 76.2 microns (1 to 3 mils) in thickness, as supplied by Mobil Chemical, Films, Division, Rochester, New York Prior to printing the upper containment layer 5, 5 ', on the silicone layer 3, the silicone surface must be treated in a corona. wetting uniformity of the printing materials and still allows the release of the transfer layer 4. Preferably, the corona treatment is applied to the carrier layer 2 and the silicone layer 3 shortly before the first printing of the layer is applied of upper containment 5. An objective treatment level should be approximately 30% of 3.5 kW. During the handling of the carrier layer 2 coated with silicone, care must be taken not to scratch the silicone layer 3. The scratching of the silicon layer 3 would allow the upper containment layer 5 to make contact and adhere to the underlying polypropylene film 2, which could adversely affect the transfer of the transfer layer 4 during application. The containment layer 5, - 5 'consists for example of non-pigmented ink and has several functions. First, it retards or prevents the penetration of water into the underlying ink layer 7, 7 '. As the layer 5, 5 'is printed wider than the adjacent ink pattern 7, 7', it forms part of a wrap that completely surrounds the colored ink layers 7, 7 '. In addition, the upper containment layer 5, 5 ', provides a consistent medium between the inks and the silicone release surface 3. The layer 5, 5 'is very important for the total transfer capacity of the label, and must be applied to a weight of at least 1.4 g / m2. important, that after the application of the upper containment layer 5, 5 'this layer is free of air bubbles and small holes. In addition, the top containment layer must be dry before printing the subsequent ink layer 7, 7 'thereon. After printing of the top containment layer 5, 5 'on the release layer 3, an optimum release force of 100 g or less must be measured in a standard tape release test. Within five hours after application, ~ the release force of the top containment layer will be approximately 60% smaller, or 40 gr. With the necessary detachment force, the containment layer 5 must be completely removed. A suitable material for the top containment layer 51 is available from Environmental Inks and Coatings, Morganton, North Carolina under type number 1304.

Examples of a preferred ink for the ink layer 7, 1 'include an organic material having water as available from Environmental Inks and Coatings, Morganton, North Carolina, under the type number Aqua BW EH-31721, EH 53016 ,. EH 90967. These inks have a high stability even at temperatures above 200 ° C without discoloration or loss of adhesion. The lower containment layer 6, 6 'provides a strong interface between the adhesive layer 8, 8' and the colored ink layers 7, 7 '. It is formulated to chemically anchor to the ink and provide excellent wetting and bonding of the adhesive layer. The lower containment layer 6, 6 'is coupled out of the ink layer 7, 1' to the upper containment layer 5, 5 ', such that a closed envelope is formed around the separate ink patterns 7, 7'. . A suitable material for the lower containment layer 6, 6 'is available from Environmental Inks and Coatings under type no. XP 11358. The adhesive layer 8, 8 'can be formed by an organic material having water which is printed on a number of consecutive flexographic stations such as three stations, or it can be covered by flow over a simple station. The adhesive layer 8, 8 'can also be applied by a simple rotogravure printing station. Preferably the adhesive 8, 8 'is activated by heat and has a tackiness to tackiness temperature of 80 ° C to 107 ° C. The preferred weight of the adhesive is approximately 3.5 g / m. "The layers of the transfer layer 4 can be applied to a flexographic printing press with up to 10 printing stations, five stations can be used for the printing of the layers., 5 ', 6, 6' and the adhesive layer 8, 8 'which may be composed of three separate adhesive layers. Five types of 7, 1 'color ink can be applied using the five remaining printing stations - graphics. Instead of a flexographic printing process, a rotogravure press equipped with a corona treater can also be used. Because the coated material is heavier than in the flexographic process, only three rotogravure printing stations may be necessary for the application of the containment layers 5, 5 'and 6, 6' and the adhesive layer 8, 8 ' .

In addition, rotary stencil printing processes can be used for the application of layers 5, 5 ', 6, 6' and 8, 8 '. After printing the lower containment layer 6, 6 ', care must be taken that it extends beyond the perimeter of the ink patterns 7, 7' but remains within the perimeter of the upper containment layer 5, 5' . It is preferable that the adhesive layer 8, 8 'extend beyond the perimeter of the lower containment layer and conform to the perimeter of the uppermost containment layer 5, 5'. Figure 2 shows a schematic side figure of a box washing apparatus for removing from the boxes 12 the transfer layers according to the present invention which are supplied to the box washer 10 by means of a conveyor 11. The boxes 12 are first conveyed to the pre-rinse station 13 and sprayed by a pre-rinse solution which is applied from a number of nozzles 14 located above and below the conveyor 11. The speed of the conveyor 11 is such that the residence time of box 12 in the pre-rinse station is between 6 and 8 seconds. Temperature of the pre-rinse solution is 60 ° C. The pre-rinse solution preferably comprises a 0.5% sodium hydroxide solution. After passing through the pre-rinse station 13, the boxes are transported through a soaking station 15 via a downward sloping section 16 of the shuttle. The residence time of the box in the soaking station is between 10 and 40 seconds. In the soaking station, the box is completely submerged and a soaking solution is recirculated in the soaking station 15 by means of the nozzles 35, to cause turbulent soaking conditions. The turbulent soaking conditions may include the recirculation of the liquid from the soaking station 15 via the nozzles 35 at a rate of 60 m 3 / h for a total volume of the 5 m 3 solution. It is important that the transfer layers be completely removed from the boxes 12 in the soaking station 15, without any pieces remaining on the boxes. Such remnant stations could, when dried, adhere firmly to the boxes and form an undesired contamination of the box surface.

From the soaking station 15, the boxes are transported via the slide guide 17 of the conveyor with an upward inclination towards a post-in station 18. The post-rinse solution may comprise water at a temperature of 30 °. C. The residence time of the boxes in the post-rinse station 18 is between 6 and 13 seconds. Connected to each rinsing station 13, 18 and the soaking station 15, are the screening stations 20, 21 and 22. Each screening section comprises a rotating band screen 23, 24, 25, which are driven by the motors 26, 27 and 28, respectively. The pumps 29, 30 and 31 draw rinsing liquid and the soaking liquid from each respective station through the rotating sieve bands 23 ~, 24 and 25 at a speed of for example 60 m3 / h. The screened liquids are recirculated back to the nozzles 14 and 19 in the pre-rinse and post-rinse stations 13, 18 respectively and to the soaking station 15. Figure 3 shows a cross-sectional view along the lines III-III of Figure 2. It can be seen that the sieve band 24 it is rotated about two rollers 37, 38. The upper end of the screen strip 24 extends above the level of the soaking liquid in the soaking station 15. The screen strip 24 comprises a screen element similar to a double layer band, with a mesh size of 2 millimeters. During the operation it is important to continually rotate the screen band 24 to prevent the label pieces coming from the transfer layer that are broken into pieces in the soaking station., tapping the sieve band. The spray nozzle 39 cleans the surface of the screen elements in the form of a strip by high pressure water or air jets. The removed label elements are collected in a collection bin 40. It was found that a very efficient removal or disposal of the labels from the boxes 12, is achieved by the use of a 0.5% sodium hydroxide solution in the pre-rinse station 13 and the soaking station 15. No However, it is also possible to apply a pretreatment material on the labels, before the entrance to the box washer 10, which acts to soften the label before the entrance to the scrubber of boxes. For example, an active surface component may be sprayed onto the boxes 12 when traveling to the box washer 10. It is also possible to apply a gel-like material of a chemical composition that begins by attacking the label before entry to the box washer 10. In such a case it may be possible to use water only in the box washer 10, instead of the alkaline solution. Figure 4 shows an alternative embodiment of a transfer label according to the invention comprising a reinforcement layer 48, a silicone release layer 49, and a transfer layer 50. The ink layer 52 of the layer Transfer 50 is a continuous layer which for example can have dimensions of 10 centimeters. The upper containment layer 51 and the lower containment layer 53 envelop or pigeonhole the ink layer 52 and couple to each other around the perimeter of the ink layer. With this, a simple envelope is formed around the ink layer 52. During the removal of the transfer layer 50 from a container to which it has been applied the transfer layer 50 can be broken into several pieces. With this, the wrap formed by the upper and lower containment layers 51, 53, will break. However, it was found that in that case enough contention still occurs to prevent the fiber layer 52 from dissolving in the wash condition. In the embodiment .in Figure 5, the ink layer 52 is formed of separate zones 52. , 52 '. Each zone of the ink layer can be formed, for example, by individual letters, individual phrases or individual blocks of words. The individual zones 52, 52 'can also be formed by other graphic objects. It is shown that the upper containment layer 51 is coupled to the lower containment layer 53 around the perimeter of each individual ink zone 52, 52 '. With this, wrappers are formed around each individual ink zone, and efficient containment is possible. In the embodiment of Figure 6, the containment layer 51 is formed of separate zones 51, 51 '. Through the open areas between the spaced zones of the containment layer 51, 51 ', the wash solution can easily penetrate and attack the underlying containment layers 53 and the adhesive layer 5.

As shown in Figure 7, the adhesive layer 54, the bottom containment layer 53 ,. the ink layer 52 and the upper containment layer 51 are each printed to register and form separate zones 51, 51 ', 52, 52', 53, 53 'and 54, 54'. Such a transfer layer has a very attractive appearance and the surface of the container is clearly visible between each individual ink zone 52, 52 '. With this specific construction, a very fast washing capacity is achieved, since the washing liquid can very quickly attack the adhesive layer 54, 54 'as it penetrates through the open areas between each ink zone 52, 52'. As shown in Figure 8, a transfer layer according to the present invention can be comprised of several parts. For example, a graphic object 55 such as an image may consist of a simple ink layer which around its perimeter 55 ', is enclosed between a top and bottom containment layer, of a structure as shown in Figure 4. Instead of the graphic object 55, separate lines of text 56 can be enclosed between a top and a bottom containment layer, for example with a structure according to Figure 5, Figure 6 or Figure 7. As indicated in 58, the individual letters of a phrase can each be individually enclosed between the upper and lower containment layer. Figure 9 shows a schematic view of the process of applying a transfer layer from a transfer label according to the invention to a returnable box 59. The label application process will now be described for the purpose of progression. Station 60 shows the step of surface treatment and temperature stabilization by means of a pre-heating treatment using a flame heater or burner 60 '. For the adhesion of two polymeric materials to occur, many factors such as neatness, pressure, temperature, contact time, surface roughness, movement during bonding and stickiness of the adhesive film must be considered. An additional important consideration is the critical surface tension. The commonly accepted method for measuring critical surface tension is with a Dyne solution, which is well known. For the Most applications in adhesives, the critical surface tension of polyethylene is 31 dynes per centimeter. A series of tests were performed, which demonstrated the best adhesion of the previously described adhesive to the polyethylene surface, and a treatment level of 60 to 70 dynes per centimeter was necessary. Additional testing of commercially available equipment showed that the flame treatment optimized the cost of capital, the operating costs and the time required to achieve the critical surface treatment required. In order for the adhesive to achieve and maintain stickiness or adhesion quickly, it is necessary to heat the polyethylene case 59 in station 61 before the adhesive label is in contact therewith. To avoid deformation of the container, it is desirable not to heat the surface above 93 ° C (200 ° F). Since the surface temperature left by the flame treatment is about 52 ° C (125 ° F) it is necessary to heat the surface to approximately 24 ° C (75 ° F) at station 61. Here again, many options are available for The warm-up. Hot air, additional flame heaters, gas-fired infrared panels and ceramic panels Electricals were all tested and found to be either too slow or difficult to control. It was found that a fused, flat, electrically heated quartz emitting plate 61 'with zone band control for the. Localized label transfer, could provide maximum transmission of free air of infrared energy without effects of environmental factors. With an emissivity of 0.9 for polyethylene, a desired emitter plate temperature from 900 ° C (1652 ° F) up to 940 ° C (1725 ° F) will emit the most efficient wavelength (2.5 to 3.2 μm) of infrared energy by maximum or peak absorption. The unit tested was rated at 60 watts per 6.45 cm2 (1 inch ^). The time to heat the polyethylene surface to the required 24 ° C (75 ° F) was 4.5 seconds at a distance from the emitting plate from 2.5 centimeters. Station 62 illustrates the method of label application whereby the printed ink materials are transferred from the polyethylene film substrate to the polyethylene surface, using the tactile characteristics of the heat activated adhesive, to overcome the bonding of the layer from transfer to corona-treated silicone coating The factors influencing the transfer are the contact time, temperature and pressure applied during contact, and the tension of the film during contact, particularly the tension of the film after the contact. release of the ink. The diameter of the pressure roller 63 is also a factor, but it is not a variable. For this application the diameter of the roller is 38 mm. Roller 63 is made of silicone rubber on a steel core, with the rubber durometer in the range of 50 Shore A to 80 Shore A. It should be noted that the distortion (flattening) of the rubber roller is less than a durometer higher, consequently the contact area is smaller and the transfer pressure is higher. This is important at higher linear speeds where contact time is minimized. In this way a box that moves at 18.3 meters per minute (60 feet per minute) beyond a roller of 38 mm in diameter, will have a contact time of 1 millisecond per 1 degree of rotation of the roller, where there is no distortion of the roller. The pressure of the roller is provided by an air cylinder 64 activated by a valve of conventional solenoid, which in turn is operated by d, os (2) switches in proximity, one to advance the roller and another to retract it. Other means, such as mechanical bonding are obvious and will not be listed here. The pressure is distributed across the length., Of the cylinder and for this particular label, the transfer intervals of 12 to 17 kilograms per centimeter of roller length are desirable. Thus, the invention results in the film being advanced at exactly the same speed as the box that is moving beyond the roll, by virtue of the heat activated adhesive, which adheres to the surface of the box, high energy The pressure roller 63, which rotates freely, maintains the same tangential velocity as the linear speed of the film and the box. In this way, the ink is transferred completely and without distortion. For purposes of rapid and complete adhesion, the adhesion roller 63 is molded to a hollow core. Suspended within the hollow core is a resistance heater operated through a controller. The heating element, adjusted to 500 W, will keep the surface of the roller any predetermined temperature. For purposes of the invention, the surface temperature of the roller is in the range of 120 ° C and 190 ° C (250 ° F and 370 ° F). Many polymer films coated with silicone can be used for the printed substrate. High temperature films such as polyester can be operated in continuous contact with the hot roll. Low temperature films such as polypropylene should be prevented from coming into contact with the hot roll during pauses in the labeling operation. To achieve this, film guides 65 are used to support the film when the roller is retracted. The guides 65 are mounted to maintain a clearance of approximately 13 mm between the guides and the labeled surface. At the same time the roller is retracted approximately 13 mm behind the film. By keeping those spaces free, scratching and distortion of the film such as polypropylene is avoided. High temperature films would not require guides. It has also been discovered that the tension of the film, especially on the exit side of the roller film, is important to complete the transfer of the ink. Through tests, it was found that a continuous voltage of approximately 2.5 kilograms is useful. This is achieved through an arm or spring loaded oscillating roller. Conventional clamping rollers and step motors are used to advance the film to the next label and place it precisely, using a printed mark to fire an optical scanning device. The protection of the ink against scratching by the casual handling, as well as the assurance of its ability to resist environmental conditions when subjected to outdoor storage, is achieved with the application of an emulsion of wax in water based on acrylic in station 66. This is applied by a roller applicator 68 which is supplied from a wet roller with a controlled amount of coating. The control is achieved with a scraper blade. The coating extends far beyond the edges of the ink pattern and seals the edges of the intrusive moisture.

The final processing step is to coalesce the layers of the coating, the label ink, and the adhesive in the station 67 by means of the flame heater 67 'and also to interdiffuse the adhesive layer with the polyethylene substrate formed by the box 59. This discovery was made through extensive testing of many heating systems. Since it was discovered that flame treatment is the best technique that could provide the surface energy required for label adhesion, it was discovered that the flame treatment of the label and the coating compound was the best technique that could be developed. the required durability of investment in water without sacrificing the mechanical properties or altering the visual characteristics of the applied label, or the distortion of the polypropylene case 59. To illustrate the various properties that influence the adhesion and the washing capacity of the layer of preferred transfer according to the present invention, the following tests were carried out, including a wash test, a pencil scratch test, a water uptake / release test and a water test. water vapor transmission rate, as described hereinafter. Washing Test To determine the optimal washing conditions for the labels according to the present invention, a transfer layer 50 having the configuration as shown in Figure 4 was applied to a polyethylene box. The dimensions of the label were approximately 10. by 10 centimeters and the adhesive layer 54 was a 100% urethane adhesive with an adhesion temperature of 79 ° C. The labels were applied to the box with a roll temperature 63 in Figure 9 of 155 ° C at a roll pressure of 2.5 bar. The preheating temperature of the box (in stations 60 and 61 of Figure 9), - was 75 ° C. The speed of the boxes 59 through the label applicator was 40 boxes per minute. To determine the influence of the post-treatment temperature with which the boxes were heated after the application of the labels in station 67 of Figure 90, the post-treatment temperatures of 40 ° C, 65 ° C and 90 ° C. After the application of the label, the Boxes were stored for at least 24 hours at a temperature of 20 ° C. The boxes to which a label was applied were afterwards soaked in a 0.5% sodium hydroxide solution at temperatures of 20 ° C, 50 ° C and 70 ° C. The soaking of the boxes was carried out in a 20 liter soaking bath without turbulence, for a soaking time (10-50 seconds) such that after spraying the box soaked with a shower at a speed of 6 liters / minute, the label was completely removed within 2 seconds. A second group of boxes was prepared where after the application of the labels, a wax coating layer was applied, as in station 6 of Figure 9. The results of the soaking times required for the removal of the labels within 2 seconds, versus the post-treatment temperature, are given in Tables I and II. From Table I, the results of which are shown graphically in Figure 10, it can be observed that for labels to which the wax layer was not applied, the soaking time drastically decreases at the temperatures of the soaking solution above 20 ° C. For post-treatment temperatures thermal temperature of 90 ° C, the durability of the label was increased and the soaking times remained above 5 seconds.

TABLE I washing test .of box (no wax coating was applied) It was found that an optimum thermal post-treatment temperature was between 65 ° C and 90 ° C. At thermal post-treatment temperatures above 65 ° C, very little coalescence of the applied transfer layer was achieved. such that the transfer layers applied had insufficient durability and could be very easily removed during storage and use. At post-heat treatment temperatures greater than 90 ° C, the durability of the transfer layer became very large, and rapid removal times could not be achieved in an economically feasible manner. During the period of spraying with the spray head or shower, it was observed that after soaking, the labels were uncoupled from the box and broke into several pieces (2 to 4). When before the flame treatment step at station 67 in Figure 9, a wax layer is applied at station 66, the durability of the labels is improved, and the soaking times are increased. From Table II it can be seen that for a caustic solution at 0.5%, the wax coating leads to more soaking times prolonged The results of Table II are shown in graphical form in Figure 11. Table II box washing test (with applied wax layer) It was observed that when trying to remove the labels as they were tested in the washing test described above, only with water jets at high pressure at 20 ° C and a pressure of 120 bar, at a conveyor speed of 15 meters per minute and at a spray angle of 90 ° at a distance of 10 centimeters, the removal of the label was not achieved. Even for labels without any wax coating and without thermal post-treatment, removal by means of high-pressure water jets was not possible.

Scratch Test with Pencil The purpose of the pencil scratch test is to identify the minimum or maximum durability of a label that can be obtained by taking different measurements, such as the use of a covering wax layer and heat treatment to cause the coalescence of the layers. the label. The boxes with labels that were applied with different post-heating temperatures, with and without wax, have also been tested. The labels were the same labels that were used in the washing tests previously described, and were applied to the boxes under the same conditions. The scratch tests with pencil were carried out with a "scratch resistance tester model 435" supplied by Ericson (PO Box 720, D-5870 Hemer, Germany). During the scratch test, a pencil with a plastic insert was used to scratch the label at a 90 ° angle horizontally in the middle part of it. After application of the label, the boxes were stored for at least 24 hours at a temperature of 20 ° C. Before scratching, the boxes were soaked in water without turbulence at 20 ° C. The results of the scratch test are given in Table III and Table IV in which the scratching results are given in N.

Table III scratch test with pencil (in N) label without wax coating Table IV Scratch test with pencil (in N) label with wax coating From Tables III and IV it can be seen that the post-heating flame treatment does not appear to influence the scratch resistance of the transfer layers significantly in the dry state. The durability of the transfer layer is nevertheless increased by post-heating flame treatment, as is apparent from the greater hardness of the pencil after soaking. From Table IV it appears that the application of a wax-coating that covers the label, improves the scratch resistance of the dry label, significantly. It was found that for high temperatures of post-heating flame treatment of 110 ° C in combination with a wax coating, a scratching force of 8 Newtons was achieved. Labels with a hardness of 8 Newton's pencil are considered semi-permanent labels that can not be removed in an economically feasible way. Also, at post-heating temperatures above 90 ° C, problems occurred during the labeling because at these temperatures the polyethylene boxes become fragile after a few applications, it was found that the pigments in the boxes are discolored and deformations of the softened boxes occur on the conveyor and the granulator. At a post-heating temperature below 65 ° C, it was found that the resistance to labels is insufficient for labels that did not have a wax coating. For labels without a wax coating the pencil hardness, objective, in the dry state should be around 1.2 Newton and the soaking time until the scratching force falls below 0.3 Newton, should be less than 3 minutes. For a wax-coated label, the target scratching force should be approximately 5 Newtons in the dry state, and the soaking time until the scratching force falls below 0.3 Newtons should be less than 10 minutes. It was found that the transfer layers having the above properties have an optimal combination of durability and wash capacity.

Water Capture Test The labels according to the present invention can be easily removed from a container, in particular from a plastic box due to its specific permeability in water, which allows the soaking solution to penetrate the label, and subsequently breaks the label into pieces and uncoupling the container. It was found that the preferred labels have a water absorption of about 5 g / m2 after 3 hours in a water uptake test, as described below. The labels according to the invention have a water uptake value greater than 0 and less than 100 g / m2 in 3 hours. The water release of a preferred label was 4.5 g / m2 within 30 minutes in the water release test, as described below. Preferred labels according to the present invention will have a water release value greater than 0 (a complete barrier) and less than 100 g / m2 after 3 hours. Two samples were prepared ", each sample containing 2 labels of a thickness of 12.7 microns each at 22.4 ° C and 48% relative humidity, each sample having a surface area of 85.8 cm2 For each sample, two labels were applied on a single piece of clear glass of 7.62 cm x 22.86 cm x 0.05 cm (3 inches x 9 inches x 0.02 inches) Due to the extremely low weight of the labels it was necessary to apply two labels per piece of glass to obtain a weight that could register within the range of an electronic scale in grams of two decimals. The samples were prepared as follows: the glass supports were perfectly cleaned and placed in a warming oven until an approximate temperature of 121 ° C (250 ° F) was reached on the surface of the glass. The glass was then removed from the heating furnace and placed on a silicon rubber mesh. A label was immediately fitted on the glass and the surface was secured by the use of a silicone roller. Roller pressure was continuously applied to the full length of the label, until all trapped air was removed (approximately 5 to 6 movements back and forth). After the glass had cooled, the carrier label was removed. After this the opposite side of the glass plates was labeled by heating a clean aluminum plate (slightly larger than the glass plate) to approximately 121 ° C (250 ° F) in a convection oven, then placing the glass on the surface of the aluminum plate (label surface facing down) which allowed the heating of the upper glass surface. The label was then applied and secured in place by the silicone roller as described above. Once again, when the glass cooled, the carrier film was removed. Next, a wax coating having a dry weight of 0.043 grams was applied to the surface of both labels. In the final step, using a flame of propane oxidation, flame treatment was applied to both labels by rapidly passing the flame through the entire surface of the label sample. Once the samples were cooled, the labels were ready for the water uptake test. A stainless steel immersion tank of 33.66 centimeters in diameter and 24.13 centimeters in height was filled with deionized water. Care was taken that the water level was deep enough to allow the total immersion of the sample. The sample was placed with the short dimension adjusted perpendicular to the bottom of the tank. The glass supports were placed on a thin wire frame in the immersion tank. A thermocouple was installed inside the water immersion tank. After each period of time, as given in Table V, the sample was removed from the tank, the excess surface water was air dried, the sample was weighed and placed back in the tank. This procedure was continued for the duration of the test. The results are shown in. Table V. with respect to sample 1, this sample reached its maximum absorption of 0.04 grams at the 3-hour mark, and maintained its level at the 5-hour mark before exhausting its ability to retain water at this level. After the 5 hour period, the label lost its ability to retain water. It is believed that this phenomenon was caused due to the structural degradation of the label. For sample 2, this sample also reached its maximum absorption of 0.04 grams at a 3-hour mark. At the 5 hour mark this sample was finished "tested in the preparation for the water release test described below." From the water uptake test, it can be deduced that a preferred level of a thickness of 12.7 microns it has a water uptake value of 0.04 g / 85.8 cm2 or approximately 5 g / m2 after 3 hours at room temperature.

Table V Water Capture Test In order to calculate the weights in grams of the individual labels from the data in Table V, reference is made to the following: Each sample incorporated the use of two labels. To calculate the weight of Sample 1 at 1:00 p.m., subtract the reading from 8:00 a.m. of reading at 1:00 p.m. and divide by 2 As in the example: reading at 1.00 p.m. 59.85 reading at 8 a.m. 59.77 0.08 / 2 = 0.04 grams Water Release Test Immediately after the conclusion of the previous Water Capture Test, Sample 2 as prepared above was subjected to the water release test. The sample was air dried to remove excess water, weighed and the data recorded. The sample was first exposed to room temperature for half an hour and weighed. Half an hour after weighing the sample, it was placed in a preheated test oven (53 ° C) (small electrically heated oven, Quieny Lab Inc., Model 20 laboratory oven or equivalent). The sample was left in the preheated oven for more than an hour and weighed. After this the sample was placed back into the test furnace and remained there for 3.5"hours From Table VI it can be concluded that the water absorbed by sample 2 was released within 30 minutes of exposure at room temperature and environmental humidity (48%) In fact, the sample registered a weight loss of 0.01 grams from its original weight, which might seem to indicate that the label was not perfectly dried in the installation .. Thus, a label preferred of size of 85.8 cm2 and 12.7 microns thick has water release greater than 0 and less than 0.10 g / 24 hours with an average release of 0.045 g within 30 minutes, given these parameters.

Table VI Water Release Test Water Vapor Transmission Rate Test The optimum combination of durability and washing ability of the label according to the invention is at least partly due to the permeability of the label for the soaking solution. A sample of the transfer layer of the same type as tested in the test Uptake / release of water with a thickness of 12.7 microns was tested for the transmission of water vapor. A 25 milliliter glass container with a circular hole of 15.9 millimeters diameter was cleaned with acetone and filled with approximately 10 milliliters of deionized water. The area of the container orifice was heated to approximately 47.8 ° C (118 ° F) and a circle segment of the transfer layer was firmly applied using a small piece of silicone rubber as a pressure pad. After the container / label had cooled, the reinforcing film was gently removed. The sample preparation was completed by the addition of a wax coating (0.001 g across the 1.99 cm2 surface) and allowed to air dry. A second glass container of the same dimensions as described above was thoroughly cleaned with acetone and filled with 10 milliliters of deionized water. The orifice area of the sample was also heated. This sample was used as a control sample. The completed samples were then weighed at various intervals in a time period of 26.6 hours. The speed of transmission of water vapor over the The total time of the experiment equaled 568.75 g / m2 over a period of 24 hours at 22.2 ° C at 46% relative humidity. It was found that a water vapor transmission rate "in the idle state" was not achieved until approximately 28 minutes from time 0. When the "rest" state data are used after 28 minutes from time 0, It was found that the water vapor transmission rate is approximately 526.93 g / m2 in 24 hours. For the control sample without a label, a water vapor transmission rate was found in the total experiment time of 1085.7 g / m2 in 24 hours. The water vapor transmission rate of the preferred label according to the present invention will fall between 50 g / m2 and 750 g / m2 after 24 hours (22.2 ° C, 44% relative humidity), preferably around 500 g. / m2 after 24 hours.

It is noted that with respect to this date, the best method known to the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following:

Claims (26)

1. A transfer label that comprises a reinforcing layer and a transfer layer, which is freely coupled to the reinforcement layer, the transfer layer comprises an ink layer, characterized in that the transfer layer comprises on each side of the ink layer a top and a bottom containment layer, respectively, the top containment layer and the bottom containment layer make contact with each other outside the perimeter of the ink layer, to form a closed envelope around the top layer ink .

2. The transfer layer according to claim 1, characterized in that the ink layer comprises separated zones of dimensions between 0.5 mm2 and 500 cm2, the upper containment layer and the lower containment layer make contact with each other outside the zones separate, to form individual wrappers around each zone of the ink layer.

3. The transfer layer according to claim 1, characterized in that most of the wrappings around the separated areas of the ink pattern remain closed when the transfer layer, after having been applied to a container, is removed from the container in a washing process using a washing liquid.

4. The transfer layer according to claim 4, characterized in that the transfer layer in the washing process is broken in at least 4 pieces under turbulent soaking conditions in an aqueous liquid of a temperature lower than 100 ° C, preferably lower than 70 ° C, within a soaking time of not more than 20 minutes, preferably not more than 10 seconds and uncoupled from the container, where the size of most of the pieces formed after the breaking of the transfer layer is not It is smaller than the dimensions of the separate areas of the ink pattern.

5. The transfer layer according to any of the previous claims, characterized in that the ink is soluble in water.

6. The transfer layer according to any of the previous claims, characterized in that the containment layer comprises a non-pigmented ink, the lower containment layer contains an adhesive.

7. The transfer layer according to any of the preceding claims, characterized in that the upper containment layer is discontinuous, and is registered by the ink pattern.

8. The transfer layer according to any of the previous claims, characterized in that the lower containment layer is discontinuous.

9. The transfer layer according to any of the preceding claims, characterized in that the transfer layer was of the separate areas of the ink pattern is permeable for the soaking liquid.

10. The transfer layer according to any of the previous claims, characterized in that the transfer layer comprises a layer of adhesive, the adhesion or tackiness of which is at least reduced by contact with the soaking liquid, preferably when dissolved in the soaking liquid.

11. The transfer layer according to claim 10, characterized in that the adhesive layer is discontinuous and is located to register within the ink pattern.

12. The transfer layer according to claim 3 or 4, characterized in that the soaking solution is an aqueous alkaline solution.

13. The transfer layer according to any of the preceding claims, characterized in that it has a thickness of less than 30 micrometers, preferably less than 20 micrometers. and a weight of the containment layers between 1 g / m2 and 10 g / m2.

14. The transfer layer according to any of the preceding claims, characterized in that it comprises an adhesive layer of a weight between 1 and 10 g / m2, preferably between 3 and 7 g / md

15. The transfer layer according to any of the preceding claims, characterized in that the adhesive layer comprises at least two sublayers, the tack or adhesion of the sublayer which after coupling to a container is closer to the container has a tack or adhesion less than the layer of adhesive located farther from the container.

16. The container, characterized in that it comprises a transfer layer that has been applied using a transfer label according to any of the previous claims.

17. The container according to claim 16, characterized in that the cover layer is applied on the transfer layer, whose cover layer comprises an acrylic wax.

18. The container according to claim 17, characterized in that the cover layer is coupled during or after coupling to the transfer layer to the container.

19. The container according to claim 16, 17 or 18, characterized in that the transfer layer has been heat treated after application to the container at a temperature between 40 ° C and 100 ° C, preferably between 50 ° C and 90 ° C.

20. The container according to any of claims 15 to 19, characterized in that it comprises an application surface for receiving the transfer layer, whose application surface has a surface tension of at least 60 dynes per cm.

21. The container according to any of claims 16 to 20, characterized in that the label on the container has a pencil hardness between IN and 7N in its dry state, and a pencil hardness of less than 0.5N after a soaking time between 1 and 15 minutes in water as a soaking solution at 20 ° C.

22. The container according to any of claims 16 to 20, characterized in that the label on the container has a water collection value after 3 hours, greater than 0 and less than 100 g / m2, preferably approximately 5 g / m2. .

23. A method for washing a container, according to any of claims 16 to 22, characterized in that it comprises the steps of: placing the container in an aqueous soaking solution, during a soaking time not exceeding 20 minutes, preferably not greater than 1 minute, the temperature of the soaking solution is lower than 100 ° C, preferably lower than 70 ° C, while causing turbulence in the soaking solution, such that the label breaks in at least 4 parts, each part not less than 5 microns and is uncoupled from the container, most of the remaining ink is contained within the wrappers, pumping the soaking solution through a sieve, and collecting the pieces of the label on the screen, cleaning periodically, preferably continuously, the screen, by collecting and removing the label pieces.

24. The method according to claim 23, characterized in that the size of the screen openings is between 0.1 mm and 10 mm, preferably between approximately 2 mm.

25. The method according to claim 23 or 24, characterized in that it comprises the step of crashing jets of water on the container before and / or after the placement of the container in the soaking solution.

26. The method according to claim 22, 23 or 24, characterized in that the soaking solution comprises between 0.1 and 5% by weight, preferably 0.5% of NaOH. SUMMARY OF THE INVENTION The invention relates to a transfer label comprising a reinforcing layer and a transfer layer, which is freely coupled to the reinforcement layer. The transfer layer comprises an ink layer and on each side of the ink layer a top containment layer and a bottom containment layer. The upper containment layer and the upper containment layer contact one another outside the perimeter of the ink layer to form a closed envelope around the ink layer. The transfer label according to the present invention can be applied to a container such as a box, and can easily be removed therefrom in a washing process without the ink dissolving in the washing liquid.