EA011898B1 - Label for glass containers and method for removing thereof - Google Patents

Abstract

The present invention relates to a label for an article, in particular to reusable containers, such as a bottle. The label bonded to a glass bottle and removed therefrom under the action of a hot washing fluid comprises a backing layer which is a polymeric film and an adhesive layer for bonding the label on to the article, the adhesive layer comprising a pressure sensitive and heat sensitive adhesive material is preferably non-resinated and acrylic-based modified by the addition of anionic, amphoteric, cationic, non- ionic surfactants in an amount not more than 5%, whereby the peel strength of the adhesive is reduced by at least 30%, heated not in the presence of a washing fluid from ambient temperature to temperature in the range 40 C to 120 C, so after the removal the label under the action of a hot washing fluid, the adhesive layer remains stick to its back surface. The invention also relates to a glass bottle provided with said label and to a method of removing the label from a bottle.

Description

FIELD OF THE INVENTION

The present invention relates to a label for an article, in particular, but not exclusively, for an article in the form of a refillable container. The back of the label can be connected to the product via an adhesive layer, with the possibility of removing the label from the product under the influence of hot flushing fluid. These products may be glass or plastic bottles for drinks, reusable transport containers for installing individual containers (in particular, boxes containing empty or filled bottles for drinks) and other products of this type. In addition, the invention relates to a method for manufacturing a label, to the product on which it is applied, and to a method of removing a label from such an article by using a hot flushing fluid.

State of the art

For containers, such as bottles used in the industrial production of beverages, the possibility of reusable use may be provided. At each revolution, such containers are cleaned before refilling, and the labels are also removed during the washing procedure. Then the containers are refilled and re-labeled (labeled) in accordance with the type of beverage-filler. If containers, such as beer bottles, are standardized for a specific product group, the bottles returned to the brewery do not need to be re-sorted according to beer types, as would be the case for bottles with a permanent, pre-applied design. Different new labels are usually applied to the bottles only after they are filled. In the case of printing labels directly on a bottle that can withstand the washing process, it would be necessary to maintain large stocks of preformed bottles.

In the industrial beverage industry, tank washing is typically carried out by immersion and tank irrigation processes using hot (60-90 ° C.) flushing fluid, such as diluted caustic soda.

Often, paper labels with glue that acquire binding properties when wetted are used to label refillable containers. In this case, the adhesive is applied to the entire surface or in strips, and only on paper and immediately before labeling. The disadvantage of this type of label is that the worker filling the bottles must work with wet glue, and handling such labels is often more difficult than with self-adhesive labels that are already received from suppliers with pre-applied glue.

Due to the standardized washing conditions adopted in the industrial production of beverages, previously it was possible to use only paper-based labels intended to be applied using wettable glue or pressure-applied applications. During the washing off of labels at the wash station, paper properties such as water permeability and swelling are used so that the adhesive over the entire surface can come into contact with the wash liquid relatively quickly and completely separate within a predetermined wash time of several minutes. For labels applied using wettable glue, adhesive formulations are typically formulated so that the adhesive dissolves in the wash liquid. In the case of self-adhesive labels having a pre-coated coating, dispersible modifications of the adhesive are often used to ensure that the adhesive is removed along with the entire surface of the paper and does not contaminate the wash bath. The thermoplastic film materials used for many types of labels, such as polyolefins, polyesters, polyvinyl chlorides, polystyrenes and other compounds of this type, do not possess such high permeability for washing liquid and water. These films block the access of washing liquid to the interface between the adhesive and the surface of the container, as a result of which labels based on impermeable films can only be slowly separated, starting from the edge. However, without additional mechanical devices such as brushes, high-pressure nozzles and similar devices, it is impossible to completely remove the labels within a period of time acceptable from an economic point of view. At the same time, the use of these mechanical devices is undesirable due to a corresponding increase in costs.

However, in the industrial production of beverages, the need for pre-coated film-based labels is increasing. Unlike paper, such film-type labels can be artistically designed in an extremely wide range of options, they are suitable for use in a transparent form and have excellent moisture resistance, and they can be applied to containers with high speed through standardized installations. In addition, there is no need to work with wettable adhesives used for paper labels. For film-based labels, mechanical properties, in particular tensile strength and tensile strength, significantly exceed the similar parameters of paper labels. However, the problem with film-type labels is that they cannot be washed with existing washing systems as easily as paper labels that have been used so far.

One solution to the above problem is formulated in US patent No. 6680097, the contents of which are incorporated into this description by reference. According to the specified patent, the label is separated from the products with little effort. This effect is achieved through the use of etiquette.

- 1 011898 ki, the layer of which, forming the substrate for the adhesive, contains a layer of plastic film, which is stretched in at least one direction. Under the influence of heat provided by the increased temperature of the flushing fluid, and / or due to radiation heating, this layer returns to its original size, overcoming the holding force of the adhesive layer. Thus, due to the thermal effect, the area of the plastic film is reduced to the original size, as a result, the adhesive loses its holding power. It is argued that as a result, the label is gradually separated from the product, for example starting from the edge or with the formation of microchannels, so that it can be easily removed in a very short period of time.

Another material characterizing the prior art is patent document \ νϋ 02/074874, the contents of which are incorporated into this description by reference. A label is provided in which the film is a biopolymer such as cellulose.

Patent document I8 2003/0150148 A, the contents of which are also incorporated into this description by reference, describes a label having convex or indented portions corresponding to the symbols printed on the label.

Generally speaking, contact adhesives intended to impart washing properties to applications that use refillable containers can be classified as water washable, alkali sensitive and alkali soluble.

Water-based adhesives are characterized in that when used in conjunction with a suitable backing (in the most typical case, with paper due to its natural permeability), they can be removed from the product simply with water having a low or ambient temperature. In humid environments, these adhesives retain their permanent adhesive characteristics. However, under the influence of a sufficient amount of water, for example, when the product is immersed in a water bath, when rinsing with a hose or irrigation, the adhesive quickly loses adhesion with the product and the label peels off. Although the substrate may be paper having a level of moisture resistance sufficient to ensure that the label remains intact after the washing process, there are applications in which the substrate requires a paper grade dispersible in water. In addition, water-soluble materials have also been developed for special applications. In the simplest embodiment, such water-washable adhesive modifications typically contain a predetermined percentage of a water-soluble component, such as derivatives of polyvinyl ethers, although contact adhesives based on water-soluble polyacrylates are also known.

Alkali sensitive adhesives are characterized in that when used together with a proper backing (in the most typical case, paper due to its natural water permeability), they cannot be easily removed by immersing the labeled product in water having a low or ambient temperature. Such removal on an industrial scale can only be successfully accomplished through the use of hot alkaline solutions, moreover, such a procedure is usually carried out in washing machines for refillable bottles. This difference from water-washable adhesives is an important factor for applications in which a certain level of water resistance is required as a component of the proper functioning of the label. A typical example of this approach is the labeling of wine and champagne, requiring a certain level of resistance to water with ice. Usually, modified acrylic dispersions are used as said adhesives. In their compositions they contain components, a balanced proportion of which provides the required level of water resistance, but which, upon contact over the entire surface with an alkaline solution, react and thereby facilitate washing.

The category of adhesives that are soluble in alkali is characterized by the fact that when used together with a suitable substrate (in the most typical case, with paper due to its natural permeability), they, in contrast to the insoluble adhesives described above, will dissolve in a hot alkaline solution. Such adhesive modifications are designed specifically to support the paper recycling process. Patent Document I8-A-5229447 describes an alkali soluble contact adhesive, which contains 100 wt.% As an adhesive component. including polymer, and the specified polymer is obtained by polymerization of a vinyl monomer containing a carboxyl group. In addition, the specified composition as the main additive component includes 50-500 wt.h. nonionic surface-active (surfactant) agent capable of providing plasticity. It is reported that commercial applications of this particular type of glue are limited due to its high cost.

Contact adhesives are characterized by permanent stickiness at the application temperature, in particular at room temperature. When pressure is applied, they adhere to a variety of substrates, without requiring activation by water, heat or solvents, and provide sufficient adhesion when pressed with your fingers. For contact adhesives, the primary bonding is not of a chemical or mechanical nature, but rather is a polar attraction to the substrate. To ensure adhesion, this interaction requires the application of pressure, ensuring sufficient penetration of the surface. More information on contact adhesives

- 2 011898 can be found in the monograph I. Vspbsk. B.1. Neutaik Rg58ige-8ep8Y1ue Abyeuyek Tes1io1odu (Magse1 Iekkeg, 1997).

In principle, contact adhesives, due to their permanent properties, do not fall into the category of washable adhesives. However, it was shown that it is possible to ensure successful flushing for permanent adhesives with specific features described in the present description.

SUMMARY OF THE INVENTION

The present invention provides a label that can be removed from the product under the influence of hot flushing fluid. The specified label contains a substrate, which is a polymer film, and a layer of glue designed to fix the label on the product and containing a self-adhesive heat-sensitive material.

In the context of the invention, the term heat-sensitive means that the adhesive properties of the adhesive layer degrade or decrease when heated to a temperature in the range of 40-120 ° C, regardless of the presence or absence of flushing fluid. Preferably, such a decrease occurs at temperatures in the range of 40-90 ° C, and temperatures in the range of 40-70 ° C are most preferred. In preferred embodiments, the adhesive properties of the adhesive layer decrease at a temperature in the range of 50-70 ° C, and more preferably in the range of 55-65 ° C.

The expression heat-sensitive should not be interpreted as an indication of the mandatory reduction of the adhesive properties of the adhesive layer immediately after exposure to a sufficiently high temperature. Such a reduction occurs within the time period corresponding to the requirements of the washing process. Thus, said decrease in properties preferably occurs in less than 1 minute, and even more preferably in less than 30 seconds, but not more than 3 minutes after the product bearing the label is exposed to the proper temperature. However, it must be borne in mind that longer periods of time, for example, not more than 10, 8 or 5 minutes, after exposure to elevated temperature on the product should be considered as lying within the wide limits of the present invention.

An adhesive property that weakens under the influence of an elevated temperature of the product includes adhesion of the adhesive layer or its peel strength.

Preferably, the tensile strength under such an impact is reduced by at least 30%, and in some cases by at least 40% or even 50%. In particularly preferred embodiments of the invention, the peel strength of the adhesive layer is reduced to approximately 20% of the initial parameter observed under ambient conditions, i.e. the decrease is 80%.

In general, for the purposes of the present invention, a decrease in peel strength will be sufficient if the remaining peel strength of the adhesive cannot hold the label on the product when it is exposed to the mechanical force exerted by the washing liquid at high temperature during a typical industrial washing process. An industry-accepted test for peeling a glued object is described in the document ес Techschs1 Naiböök (6th ed.), As RTM1, Ree1 Abyeöy (180 °) at 300 mm / min. The peel test characterizes contact adhesive parameters such as bonding stability or peelability. Prepare test strips with a width of 25 mm, stick them to the test plate (glass or metal), and then stand for a specific period of time (usually 20 minutes and 24 hours). The force required to tear off the label material from the test plate is recorded in Newtons and adhesive transfer is evaluated. For the purposes of the present invention, it is most important that, under washing conditions, the force required to detach from the product is low, for example, not more than 5N / 25 mm. Under environmental conditions, the peel strength (peel strength) depends on what is the thermal sensitivity of the selected adhesive, as well as on the mass of the applied layer, and the peel strength can reach 25N / 25 mm.

In the context of the present invention, the peel strength is the peel strength of the adhesive layer when applying a label to a selected product, which can be made, for example, of glass, plastic, metal or ceramic.

Contact adhesive can be diluted with solvent or water or fluidized by heating. It is a combination of polymer and surfactant components, and the latter allows you to remove the label from the product to which it was attached, for a preferred period of time not exceeding 10 minutes, using water washing at a temperature in the range of 60-90 ° C. The adhesive material may have a rubber, acrylic or modified acrylic base. In preferred embodiments of the invention, acrylic-based adhesives are used, and in order to meet the above requirements, they are modified to improve the adhesive properties associated with heat sensitivity. Modification of the base adhesive material may include a surfactant additive, which may be an anionic, amphoteric, cationic, nonionic, or polymeric surfactant. In the case of the use of anionic surfactant, it may contain any agent selected from various organic sulfates, sulfonates, sulfonic acids, salts and mixtures thereof, as well as various sulfosuccinates. When using a non-ionic surfactant, it may contain ethoxylate, alcohol ethoxylate or alkoxylate.

- 3 011898

It is desirable that the surfactant is present in the adhesive material in an amount of not more than 5%, preferably not more than 3.5%, and even more preferably not more than 2%. Preferred is a reactive surfactant that adheres to the functional groups of the adhesive polymer. In this case, the possibility of washing out the surfactant from the glue layer is eliminated, for example, in a situation where the product bearing the label is immersed in water at a temperature below the level at which the glue layer loses its ability to stick. In particular, if the product is a beer or wine bottle, it can be immersed in ice water to cool the contents before use.

Preferably, the adhesive material does not contain resins, i.e. the presence of any additional tackifying agent or any other viscous substance added is a disadvantage.

Compared to contact adhesives commonly used on labels, in this case the adhesive layer may be thinner. A preferred thickness of said layer corresponds to an adhesive surface density not exceeding 15 g / m ² , possibly not even exceeding 14 g / m ² . It can be assumed that for most applications, this parameter is at least 10 g / m ² .

As noted above, according to another aspect of the present invention, a method for removing labels from an article is provided. The specified method includes:

(ί) processing the product at the preheating stage, during which the product is heated to a temperature above 40 ° C with a decrease in the adhesive strength by at least 40%, and then (i) processing the product during the washing process, during which the product (a) immersed in a shaken flushing fluid and / or

b) are treated by irrigation with flushing fluid to separate the label from the product as a result of mechanical stress, shaking and / or irrigation.

The preheating step may include immersing the product in a bath of hot water having a temperature of at least 50 ° C. In the washing step, the washing fluid may contain an alkaline solution, for example, an aqueous solution of sodium hydroxide (ΝαΟΗ) with a concentration of 1.0-2.5%.

Preferably, when removing the label from the product, a layer of glue is retained on it.

The label according to the invention may also have the features described in UK patent applications No. 0405271.8 and / or No. 0412663.7 filed by the applicant of the present invention.

So, according to the first of these applications, the layer of contact adhesive may have an inner surface facing the label substrate and an outer surface intended for gluing to the surface of the product. In this case, the outer surface of the adhesive layer before applying the label to the product contains many microchannels reaching the edges of the label.

Other properties described in this application that can be used in the label of the present invention include the following:

microchannels, if you observe them in the plane of the label, are located along the entire plane of the label or on its part;

microchannel depth is part of the label thickness;

the depth of microchannels does not exceed approximately 15 microns;

the depth of microchannels does not exceed approximately 10 microns;

microchannels have a depth of at least 1 μm;

microchannels have a depth of at least 5 microns;

the width of the microchannels does not exceed approximately 250 microns;

the width of the microchannels does not exceed approximately 150 microns; microchannels have a width of at least about 10 microns; microchannels have a width of at least about 50 microns; the minimum distance between adjacent microchannels is approximately 10 microns; the maximum distance between adjacent microchannels is 10 mm;

the polymer film for the label is selected from thermoplastic films, such as films from polyolefins, polycarbonates, polyesters, polyvinyl chlorides and polystyrenes, as well as from biopolymers such as cellophane and polymerized lactic acid (PMC);

the polymer film is a polypropylene film;

the polymer film has a thickness of 15-100 microns.

For the manufacture of the labels of the present invention, the method described in UK patent application No. 0405271.8 can be used. The specified method includes the following:

the manufacture of a composite structure containing a substrate, which is a polymer film, and a layer of contact adhesive intended for attaching labels to the product; wherein the contact adhesive layer has an inner surface facing the adhesive label and adhering thereto, as well as an outer surface for gluing to the surface of the article, and

- 4 011898 the formation of microchannels in the outer surface of the adhesive layer, and these microchannels reach the edges of the label.

According to the proposed method, microchannels can be formed by embossing the surface of the composite structure.

According to the invention described in UK patent application No. 0412663.7, the outer surface of the adhesive layer is coated with a coating, which consists of an adhesive modifying agent, before it is applied to the product.

The label can be made by the method described in the same patent application in the UK No. 0412663.7. According to the specified method, a coating consisting of an adhesive modifying agent is applied to the surface of the adhesive layer, which is opposite to the side adjacent to the label substrate.

One example of such an agent is a UV cured varnish that neutralizes glue.

In preferred embodiments, the introduction of the agent that modifies the adhesive, it serves to reduce the adhesion strength of the adhesive layer in the zone or zones of its application. However, the term glue modifying agent (modifying agent) is used in a broad sense and refers to any agent that affects the chemical, physical, or mechanical properties of an adhesive layer.

The adhesive modifying agent can be applied to the surface of the adhesive by direct printing, i.e. through screen printing, flexography, as well as letterpress or gravure printing. To increase the effectiveness of this application, the material of the front side and the adhesive part of the structure are first peeled off from the removable protective layer, which allows you to imprint the specified agent on the currently open surface of the adhesive. Then, after imprinting, the layers are reconnected, passing them through the structure in the form of a pressure roller. Any labels are provided with such a removable layer when using contact adhesive, so that during transportation and handling of the label, the adhesive layer is coated. This prevents unintended adhesion of the glue or gluing it to another product. The removable layer is removed immediately before attaching the label to the intended product.

The modifying agent can be applied to the entire surface of the label or in the form of a pattern (pattern) that fits into its outline.

The specified agent can also be applied in the form of a series of round spots with a degree of coverage of the total surface, selected in accordance with the functional requirements for a particular label and preferably corresponding to 3-10%. The printed pattern may also have a configuration in the form of square spots, parallel or intersecting lines, as well as other configurations known to specialists in this field.

The modifying agent is designed to facilitate lifting the edges of the label in the wash bath without using any mechanical means, except, firstly, the rigidity (bending modulus) of the label material, which overcomes the adhesive force to the product, and, secondly, the turbulent movement created streams of water. Then, these effects allow the washing solution to penetrate under the label and accelerate its washing, enhancing the lowering of the adhesive properties achieved through the use of heat-sensitive glue.

List of drawings

For a better understanding of the present invention and in order to illustrate its effective use, further discussion only as an example will be carried out with reference to the accompanying drawings, in which:

in FIG. 1 is a sectional view showing the initial composite structure of a self-adhesive label, in which, by means of a mechanical embossing process and using the properties of the label material described above, the printed information layer, the front material and the adhesive layer are physically modified to reproduce the pattern applied to the embossing stamp used;

in FIG. 2 shows the front side of the label shown in FIG. one;

in FIG. 3 is a cross-sectional view of an initial composite alternative structure of a self-adhesive label that has gone through a process of imprinting a modifying agent on an adhesive surface;

in FIG. 4 shows examples of patterns in which a modifying agent can be applied to the rear side of the label shown in FIG. 3.

Information confirming the possibility of carrying out the invention

The polymer film for the label of the present invention may be any suitable polymer film from which the label can be made. For complete clarity, it should be emphasized that paper does not apply to the polymer film used in the invention. Examples of polymer films are thermoplastic films, such as films of polyolefins, polycarbonates, polyesters, polyvinyl chlorides and polystyrenes. In addition, biopolymers such as cellophane and polymerized lactic acid can be used. Particularly preferred are waterproof and heat-resistant polyolefin films, with films of

- 5 011898 polypropylene, such as biaxially oriented polypropylene (BONN).

The polymer film may be a laminate or consist of a single layer. It may contain additional non-polymer, for example metallized, layers.

A transparent polymer film is preferred so that the label does not interfere with the contents of the container. If desired, the film can be painted in accordance with the color of the product to which the label is attached.

The thickness of the polymer film is typical for films of this purpose and is 15-100 microns, with an interval of 40-50 microns being preferred.

The polymer film can be processed by methods known in the art. It can be coated using techniques known in reg 8e.

Although under the influence of heat, water, or, more importantly, hot caustic washing liquid, the polymer film may wrinkle or deform in some other way, such behavior is not necessary. You can apply a film that does not wrinkle and does not deform.

Contact adhesive.

The adhesive used according to the present invention may be a contact water adhesive, although it is known that the mechanisms described in this case that facilitate label laundering could also be realized using a solvent or using a hot-melt adhesive system. The term aqueous means that water is used as a carrier (dispersion medium), in which its polymers are dispersed in the manufacture of contact adhesives. Typically, a contact adhesive is made by a process in which the polymer component of the adhesive is dispersed in a water solvent or surfactant (s), for example, in a proportion of about 50:50 of the weight of the polymer and the solvent used. Then the water is removed. A similar process is used for the manufacture of mortar adhesives (solvent based adhesives), although in this case a solvent other than water is used (usually a volatile organic solvent). In addition, it is preferable that, in a typical case, the contact adhesive does not contain resinates. This means that the contact adhesive should not contain any additional viscous substances added to it, i.e. tackifying compounds.

The mechanisms by which washing is facilitated by choosing the preferred adhesive are reduced to the fact that when the label is heated above 40 ° C, and even more preferably above 60 ° C (as is the case with a labeled container inside the washing medium, for example, the pre-heating stage time before transferring the container to the washing tank) the adhesion of the label to the container (i.e., peel strength) is reduced by 50% or more. As a result, the label is easier to tear from the product, although the adhesive retains some grip. The adhesion decreases quite quickly, preferably within 1 min of immersion at elevated temperature. This decrease helps to raise the edges of the label from the surface of the container, and the washing solution then gets the opportunity to get under the label between the adhesive layer and the product and complete the complete removal of the label by a combination of physical and mechanical means.

The effectiveness of the physical removal of the label is determined by the swirls created inside the washing machine due to the movement of its mechanism, or rather, the intense fluid flow generated by the pumps in those places of the machine where the label is removed. The label is separated from the container by the force of moving water in excess of the adhesive force to the container.

The effectiveness of the chemical removal of the label is determined by bringing the glue into contact with the hot flushing fluid. This creates the possibility of chemical interactions between the wash solution and additives present in the adhesive, such as surfactants. As a result, adhesion is eliminated and thereby re-sticking of the label to the surface of the container or to any other parts inside the machine is prevented.

It should be borne in mind that the fundamental property of the adhesive material is its significant thermal sensitivity. This is the difference from the known contact adhesives used for labels on products such as bottles and removed during the washing process. Known adhesives for labeling such products have been developed on the basis that alkaline flushing fluids such as ΝαΟΗ aqueous solution are used in conventional washing processes. Thus, in the presence of such an environment, they must dissolve or lose their effectiveness in some other way. The thermal sensitivity of such known adhesives is insufficient, i.e. their properties depend on the application of heat only (for example, by immersion in hot water) to an extent insufficient to separate the label from the product within a sufficiently short time interval, which ensures the competitiveness of the label removal system on an industrial scale .

- 6 011898

The following are other preferred properties of contact adhesive.

The adhesion of the label to the container when immersed in chilled or even ice water should remain at the same level as in ambient conditions. Thus, if completely immersed in ice water, the water does not penetrate the label during the period of time normally required when handling labeled beverage containers. The preferred resistance to immersion in ice water is set to at least 72 hours, more preferably 7 days, and in some cases it should be 21 days. During this period, water under the influence of glue should whiten to a minimum. In addition, labeled containers immersed in ice water while using the product should not show a significant deterioration in their performance in relation to subsequent laundering. This can be achieved due to surfactants that have reacted (i.e. bound) inside the structure of the adhesive layer, as a result of which they will not be washed out when immersed in water. It is known that such a problem arose for self-adhesive paper-based labels.

Preferably, when removing the label from the product, a layer of glue remains on it. This minimizes the amount of contaminants remaining inside the washing machine.

It is also preferable that the washing process of the adhesive is not substantially complicated due to its aging during the shelf life of the product. Usually this period reaches 12 months, counting from the moment of labeling, and for this period the temperature, humidity and UV radiation, which change in time, affect the labeled container.

In the process of forming the functional characteristics of the label described in this case, it is preferable to apply contact adhesive to the film substrate of the label so that the surface density of the adhesive is 10-20 g / m ² , and in the most preferred embodiment, 12-14 g / m ² . When applying glue to the label material, it is advisable to cover the entire surface of the zone with gaps between them or according to a suitable pattern.

According to the test results according to the method of testing for whitening water, described in the monograph I. Vspbsk. B. Neushap8 Rgekkige-Zepkytue Lbyyeuek Tesypoduodu (p. 558), the contact adhesive used according to the present invention according to its characteristics can be classified as acceptable, i.e. the adhesive film does not show any signs of whitening of water within the time interval of 10 s. In fact, for a number of examples of contact adhesives suitable for use in the invention, this whitening may not occur for 90 seconds or even 300 seconds.

According to the test results according to the transparency loss test method described in the same monograph (p. 558), the contact adhesive used according to the present invention according to its characteristics can also be classified as acceptable, i.e. the difference in transparency between wet and dry laminates is <8% for the adhesive film.

According to the test results according to the wet grip test method described in the same monograph (p. 558), the behavior of the contact adhesive used according to the present invention can be characterized as follows: the adhesive layer is not erased from the selected substrate after immersion in distilled water for 7 min.

According to the test results according to the wet glass adhesion test method described in the same monograph (p. 558), the contact adhesive used according to the present invention can have the properties of restoring the adhesion parameters after immersing the sample in distilled water for 7 minutes for a period of time in excess of 60 minutes when applied to polypropylene material and 30-60 minutes when applied to the film of regenerated cellulose.

For use in accordance with the present invention, contact adhesive of the brand 8E5279, supplied by the company HB EuGeer Yshyeb, is preferred.

The contact adhesive used according to the present invention is a combination of polymer and surfactant components. The latter ensures the presence of all these mechanisms and allows you to remove the label from the product to which it is attached, using water washing at 80 ° C for a period of time within 10 minutes.

More precisely, contact adhesive is preferred, when used as a label adhesive, the front substrate of which is a layer of a film of biaxially oriented polypropylene (with a possible water vapor transmission rate of approximately 3.3 g / m ² for 24 hours at 38 ° C and relative humidity 90%) with a thickness of 50 microns, the label is removed from the glass substrate for no more than 10 minutes or even faster under the influence of washing water having a temperature of 80 ° C. Wash water contains ΝαΟΗ with a concentration of 2% and 0.1% additive surfactant flushing agent, for example, brand P3 81aLiop P1i8, supplied by the company Eco1ab, 1 ps. In this test, it is preferred that the label is removed from the glass substrate faster than 8 minutes, more preferably within 5 minutes, and most preferably within 3 minutes.

When using other materials for the facial backing having increased water permeability, such as a regenerated cellulose film (with a possible water vapor transmission rate of about 370 g / m ² for 24 hours at 30 ° C and a relative humidity of 90%), the label is compared to

- 7 011898 The above option will be deleted in a shorter period of time. Such materials may have a thickness of approximately 45 microns.

In the test described above, a labeled product can be set to a minimum of 24 hours ambient exposure time (23 ° C, 50% relative humidity) before a laundering test. This allows complete completion of the interconnected processes of contact adhesive creep in cold condition and gluing to a glass surface. The glass product may be a refillable bottle, used, for example, for drinks. During the test, the dimensions of the label to be tested can be 50 mm (width) x70 mm (height), and the label can be manually applied to the glass product, using a tool that reproduces the conditions for automatic application. The washing test can be carried out in a stainless steel bath containing 12 liters of hot flushing fluid, shaken to a depth of at least 15 cm by means of a stirrer introduced from above and having a rotation speed of 250 rpm. In this case, the conditions inside the main soaking chamber of the industrial washing equipment are reproduced. The following conditions are maintained for the bath: a temperature of 80 ° C, a concentration of αΝ 2% and the addition of 0.1% of the substance P3 81aL1oi P1i8 (a washing agent based on a washing agent supplied by EcoLaB, 1 ps).

Example.

Permanent water contact adhesive, supplied by NV Eu11eg YtPey under the brand name 8E5279, was applied to the permeable material of the front substrate (a 45 μm thick regenerated cellulose film) and also to an impermeable front substrate (a layer of biaxially oriented polypropylene with a thickness of 50 μm), having withstood the surface weight of the coating on level of 20 g / cm ² . Samples were prepared measuring 50 mm (width) x70 mm (height) and manually pressed to glass refillable beer bottles, using a tool that reproduces the conditions for automatic application. Further, the labeled bottles were held at ambient conditions (23 ° C, relative humidity 50%) for at least 7 days before carrying out laundering tests for a minimum of 7 days to allow the interconnected processes of cold creep of the contact adhesive and adhesion to the glass surface to be completely completed. The washing tests were carried out in a stainless steel bath containing 12 L of hot flushing fluid, shaken by means of a mixer introduced from above and having a rotation speed of 250 rpm. Thus, the conditions inside the main soaking chamber of industrial washing equipment were reproduced. The following conditions were maintained for the bath: a temperature of 80 ° C, a concentration of αΝ2% and the addition of 0.1% of the substance P3 §1aB11op P1cg, supplied by Eco1aB, 1 ps.

It was shown that the process of washing the specified adhesive in combination with a regenerated cellulose film and a BONN film took less than 180 and less than 480 s, respectively.

As indicated above, the outer surface of the adhesive layer before applying to the product may contain many microchannels reaching the edges of the label. Thus, surface microchannels form a corresponding layer inside the adhesive, which, if observed in the plane of the label, can completely or partially cover this plane. In some embodiments, microchannels can only penetrate the label to a portion of its thickness, since it is sufficient to extend to the outer edge of the label, allowing hot wash water to lift this edge from the product to which the label is attached. When the outer edges of the label are raised, hot water opens access to the inner areas of the label, and in some cases this will be enough to facilitate the complete removal of the label from the product.

The size and density of the microchannels in the adhesive layer may depend on several factors, for example, the elasticity of the facial material and the adhesive. However, as a general recommendation, it can be indicated that the microchannels will typically have a depth of not more than about 15 microns and not less than 3 microns, and in the most preferred embodiment, 5-10 microns. Typical microchannel widths will not exceed about 300 microns with a minimum size of at least about 10 microns, and will preferably be in the range of about 50-150 microns. At least some microchannels can intersect with each other, forming a network of interconnected microchannels. Alternatively, you can create a series of microchannels, mainly parallel to each other, that is, without mutual intersections. The location of the microchannels may correspond to a regular pattern. However, this condition does not seem essential, and labels in which microchannels are randomly placed should also be considered to be within the scope of the present invention.

The exact number and location of the described microchannels can be determined empirically through a standard experiment. In the usual case, the minimum distance between the microchannels will be approximately 10 μm with a preferred value of approximately 250 μm. Such distances ensure that the amount of glue is sufficient to satisfactorily bond with the product. The maximum distance between adjacent microchannels in their order can be up to approximately 10 mm, and in the usual case it will not exceed

- 8 011898 sew 5 mm.

In one preferred embodiment of the invention, the microchannels form two series of parallel microchannels intersecting each other at a substantially 90 ° angle.

The cross-sectional configuration of the microchannels is uncritical. For example, each of them may be formed by a base and a pair of substantially parallel side walls extending from the base. Alternatively, the microchannels may have a concave cross section. This configuration is usually formed for most contact adhesives.

Microchannels in the outer surface of the adhesive layer can be formed by a process during which a composite (composite) material undergoes a stage of mechanical shape change. At this stage, the desired microchannel distribution pattern is formed on an elastic surface in the form of a series of recessed zones, and then this surface is used to compress the surface of the composite in order to mechanically deform its layers. This process is also called embossing. Embossing is a technology by which protruding or recessed areas are formed on the surface according to the shape and contours of the desired pattern (pattern). In known embossing embodiments, a pair of dies (or dies) are usually used on which a pattern to be applied is formed. Typically, one stamp reproduces the structure of another with the opposite sign. When during pressing a pair of dies is brought together under pressure by placing a piece of the workpiece material between them, the pattern is transferred to this material by deforming it in the pattern zone in directions perpendicular to the original plane. Typically, according to the present invention, the dies will represent a pair of embossing rollers, one of which has a desired microchannel distribution pattern on its surface and the other is a support on which the embossing roller exerts pressure.

The embossing of the composite structure can be done so that the pattern is applied, optionally, to the front material or to the surface of the adhesive layer, however, the first of these options is preferred.

In the embossing method of the invention, the embossing roller can be made of metal in which the desired microchannel distribution pattern is etched or engraved. As indicated above, the depth of the microchannels, as well as their desired shape and location in the template will correspond to the desired depth and location of the microchannels in the adhesive layer. During embossing of the composite structure, the distribution pattern of microchannels is transferred directly to the composite layer. The substrate of the structure is a polymer film, and in some cases, for example, when the film consists of a polyolefin, such as polypropylene, it will deform elastically and then quickly restore its original shape without retaining any picture of the distribution of microchannels. However, the material of the contact adhesive has a very high viscosity and does not noticeably flow under the conditions under which labels are made or used. Thus, the distribution pattern of microchannels will remain on the surface of the adhesive layer for a longer period of time.

An example of an embossed label is shown in FIG. 1 and 2. The label is embossed over its entire surface, and the presented pattern is intended to create a network of microchannels interconnected in the directions of both axes of the label and reaching the edges of the cut labels. The embossing depth was 7–10 μm with the width of the microchannels before being applied to the product 100-125 μm.

Glue modifying agent.

As indicated above, the outer surface of the adhesive layer before applying to the product may contain a modifying agent imprinted on the surface of the adhesive.

In one embodiment of the invention, the modifying agent serves to neutralize the adhesive at the imprinting sites of the agent. In other words, the specified agent lowers the level of adhesion to the product, and also allows the penetration of washing fluid, such as a caustic solution, through the gaps between the adhesive layer and the product.

In another embodiment, the modifying agent comprises a component soluble in the flushing fluid, for example, in a hot caustic solution. Thus, after imprinting, the indicated agent lowers the level of adhesion to the product, and also allows caustic (caustic alkali) to penetrate through microchannels formed in accordance with the printed pattern, easily soluble in contact with the hot washing fluid.

In a further embodiment of the invention, the modifying agent comprises a component that swells under the influence of heat or water, in particular under the influence of a hot flushing fluid, such as a caustic solution. Thus, after imprinting, said agent swells in the presence of a flushing fluid and, as a result, lowers the level of adhesion to the product, and also allows the caustic to penetrate through the microchannels formed by the printed pattern.

- 9 011898

The label shown in FIG. 3, can be made by printing on a narrow printing press. Exfoliating the label web, it is possible by flexographic printing to apply the adhesive neutralizer in the form of a varnish cured by UV irradiation (grade L301, supplier is Ragadop 1ik§) to the surface of the glue, followed by reconnecting the layers by passing them through the embossing roller assembly. A corresponding pattern was printed on the label web using the set of templates shown in FIG. 4 and forming a pattern in the form of round spots.

The general pattern was applied at a degree of coverage of the total surface of 3, 5, 10, 20, 30, and 40%.

The label frame, having a width of 5 mm, was applied with a degree of coverage of the total surface of 3, 5, 10, 20, 30 and 40%.

The label frame, having a width of 10 mm, was applied at a degree of coverage of the total surface of 3, 5, 10, 20, 30 and 40%.

The above percentages for the degree of coverage of the label surface refer to the area of the original image on the roller in the form of a series of round spots. In practice, a picture is formed due to variations in depth provided during the manufacture of a printing form. Then, during the printing process, these variations lead to an increase in the size of the spots of the modifying agent deposited on the adhesive. By way of example only, it can be pointed out that the degree of coverage for the original pattern of 3% can lead to a degree of coverage of the surface of the adhesive with an agent of approximately 15%.

The varnish was applied using a raster (anilox) shaft having a line density of 650 and a volume of 3.5 cm ³ / m ² .

It should be emphasized that the use of embossing technology and the introduction of an agent that modifies the adhesive are optional features of the proposed process. For the present invention to its maximum extent, these steps are not essential. With the appropriate composition of the adhesive, the labels will be adequately washed when using other, and numerous, options. However, in certain circumstances, the use of embossing and / or a modifying agent may be warranted, especially if it is necessary to speed up the laundering of the label from the product.

Claims (40)

CLAIM 1. A label attached to a glass bottle and removed from the bottle by hot flushing fluid, containing a substrate that is a polymer film, and an adhesive layer for fixing the label on the bottle, the adhesive layer containing a self-adhesive and heat-sensitive rubber-free adhesive material on acrylic base, modified by adding anionic, amphoteric, cationic or nonionic surfactant in an amount of not more than 5 wt.%, while the label applied to the glass has a strength of the separation is reduced by at least 30% when heated in the absence of a flushing fluid from ambient temperature to a temperature lying in the range from 40 to 120 ° C, whereby after separation of the label under the influence of a hot flushing fluid, the adhesive layer remains attached to its back side. 2. The label according to claim 1, characterized in that the adhesive material is an aqueous adhesive material. 3. The label according to claim 1, characterized in that the adhesive material is a solution of adhesive material. 4. The label according to claim 1, characterized in that the adhesive material is a hot-melt adhesive material. 5. The label according to any one of the preceding paragraphs, characterized in that the surface density of the adhesive layer does not exceed 15 g / m ² . 6. The label according to claim 5, characterized in that the surface density of the adhesive layer is at least 12 g / m ² and not more than 14 g / m ² . 7. The label according to any one of the preceding paragraphs, characterized in that before it is applied to the bottle, it contains many microchannels reaching the edges of the label. 8. The label according to claim 7, characterized in that the microchannels are located along the entire plane of the label or on its part. 9. The label according to claim 7, characterized in that the depth of the microchannels is part of the thickness of the label. 10. A label according to any one of claims 7 to 9, characterized in that the microchannels have a depth not exceeding 15 microns. 11. The label of claim 10, characterized in that the microchannels have a depth not exceeding 10 microns. 12. The label according to any one of claims 7 to 11, characterized in that the microchannels have a depth of at least 1 μm. 13. The label of claim 12, wherein the microchannels have a depth of at least 5 microns. 14. The label according to any one of claims 7 to 13, characterized in that the microchannels have a width of not more than - 10 011898 250 microns. 15. The label of claim 14, wherein the microchannels have a width of not more than 150 microns. 16. The label according to any one of paragraphs.7-15, characterized in that the microchannels have a width of at least 10 microns. 17. The label according to clause 16, wherein the microchannels have a width of at least 50 microns. 18. The label according to any one of paragraphs.7-17, characterized in that the minimum distance between adjacent microchannels is 10 microns. 19. The label according to any one of paragraphs.7-18, characterized in that the maximum distance between adjacent microchannels is 10 mm. 20. The label according to any one of the preceding paragraphs, characterized in that the outer surface of the adhesive layer before it is applied to the bottle is coated with an adhesive modifying agent. 21. The label of claim 20, wherein the adhesive modifying agent is a UV cured varnish and a neutralizing adhesive. 22. The label according to claim 20 or 21, characterized in that the adhesive modifying agent is applied to the surface of the adhesive by direct printing. 23. The label of claim 22, wherein the adhesive modifying agent is applied to the surface of the adhesive using a screen printing, flexographic, letterpress, or intaglio printing process. 24. The label according to any one of paragraphs.20-23, wherein the adhesive modifying agent is applied over the entire surface of the label. 25. The label according to any one of paragraphs.20-23, wherein the adhesive modifying agent is applied in the form of a pattern. 26. The label according to any one of paragraphs.20-25, wherein the adhesive modifying agent is applied as a series of spots. 27. The label according to any one of paragraphs.20-26, characterized in that the agent that modifies the adhesive is applied when the degree of coverage of the total surface of 5-10%. 28. The label according to any one of paragraphs.20-26, characterized in that the adhesive modifying agent is applied in the form of a system of parallel or intersecting lines. 29. The label according to any one of the preceding paragraphs, characterized in that the specified tensile strength is reduced by at least 40% when heated to a temperature lying in the range of 40-120 ° C. what what what decrease lowering decrease in strength 30. The label according to any one of the preceding paragraphs, characterized in that the separation occurs at temperatures in the range of 40-90 ° C. 31. The label according to any one of the preceding paragraphs, characterized in that the separation occurs at temperatures in the range of 40-70 ° C. 32. The label according to any one of the preceding paragraphs, characterized in that the separation occurs at temperatures in the range of 50-70 ° C. 33. The label according to any one of the preceding paragraphs, characterized in that the polymer film is capable of wrinkling under the influence of heat. 34. A glass bottle labeled according to any one of the preceding paragraphs. 35. The method of removing from a glass bottle labels made in accordance with claim 1, including: (ί) processing the bottle at the preheating stage, during which the bottle is heated to a temperature above 40 ° C with a decrease in adhesive strength by 10% or less from the bottle, and then (i) processing the bottle during the washing process, during which bottle (a) is immersed in a shaken flushing fluid and / or (b) is treated by irrigation with flushing fluid with the resulting separation of the label from the bottle, in which the adhesive layer remains attached to the back of the label. 36. The method according to clause 35, wherein the pre-heating step involves immersing the bottle in hot water at a temperature of at least 50 ° C. 37. The method according to p. 35 or 36, characterized in that the flushing fluid contains an alkaline solution. 38. The method according to clause 37, wherein the alkaline solution contains an aqueous solution of sodium hydroxide. 39. The method according to any one of claims 35-38, wherein the flushing fluid contains a surfactant. 40. The method according to any one of claims 35-39, characterized in that the washing fluid is at a temperature in excess of 60 ° C.