Patent Publication Number: US-2015060320-A1

Title: Labeling of items with wash-off labels

Description:
FIELD OF THE INVENTION 
     The present invention relates to labeling products. 
     BACKGROUND 
     It is known to use self-adhesive labels for labeling products. Referring to  FIG. 1 , a typical self-adhesive label  90  comprises a facestock layer  91 , a pressure-sensitive adhesive layer  92 , and a release layer  99  laminated together. Self-adhesive labels are also called as pressure-sensitive adhesive (PSA) labels. 
     The self-adhesive label may be attached to an item by removing the release layer and pressing the exposed adhesive layer of the label on the surface of the item. The adhesive layer is tacky at the room temperature, and the release layer is needed to protect the adhesive layer against dirt, and in order to prevent accidental or premature adherence to items which should not be labeled. 
     SUMMARY 
     An object of the present invention is to provide a method for labeling. An object of the present invention is to provide an apparatus for labeling. An object of the present invention is to provide a label. An object of the present invention is to provide a method for producing a label. An object of the present invention is to provide a labeled product. An object of the present invention is to provide a method for removing a label. 
     According to a first aspect of the invention, there is provided a method for attaching a label ( 100 ) to an item (ITE 1 ), the label ( 100 ) comprising a heat-shrinkable layer ( 10 ) and a heat-activatable layer ( 20 ), wherein the activation temperature (T ACT ) of the heat activatable layer ( 20 ) is higher than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ), wherein the method comprises:
         heating a portion ( 21 ) of the heat-activatable layer ( 20 ) by visible or infrared light (LB 1 ) so that at least a portion of the surface of the heat-activatable layer ( 20 ) is converted from a non-tacky state to a tacky state, and   attaching the label ( 100 ) to the item (ITE 1 ) when the surface of the heat-activatable layer ( 20 ) is in the tacky state,
 
wherein the intensity of the light (LB 1 ) is selected such that the temperature (T 10 ) of a portion ( 11 ) of the heat-shrinkable layer ( 10 ) remains lower than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ).
       

     According to a second aspect of the invention, there is provided a combination of an item (ITE 1 ) and label ( 100 ) attached to the item (ITE 1 ), the label ( 100 ) comprising a heat-shrinkable layer ( 10 ) and a heat-activatable layer ( 20 ), wherein the activation temperature (T ACT ) of the heat-activatable layer ( 20 ) is higher than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ), wherein the label ( 100 ) has been attached to the item (ITE 1 ) by heating a portion ( 21 ) of the heat-activatable layer ( 20 ) by visible or infrared light (LB 1 ) so that at least a portion of the surface of the heat-activatable layer ( 20 ) has been converted from a non-tacky state to a tacky state, wherein the intensity of the light (LB 1 ) has been selected such that the temperature (T 10 ) of a portion ( 11 ) of the heat-shrinkable layer ( 10 ) has remained lower than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ) during the heating. 
     According to a third aspect of the invention, there is provided a method of separating the label ( 100 ) from the item (ITE 1 ), wherein the label ( 100 ) and the item (ITE 1 ) form the combination according to any of the claims  8  to  11 , the method comprising:
         heating the label ( 100 ) to a temperature (T WASH ), which is higher than or equal to the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ), and which is higher than or equal to the activation temperature (T ACT ) of the heat-activatable layer ( 20 ).       

     Further embodiments of the invention are defined in the dependent claims. 
     The label comprises a heat-shrinkable layer and a heat-activatable layer. 
     The heat-shrinkable layer is arranged to shrink when heated above a predetermined temperature. 
     The heat-activatable layer may be converted from a non-tacky state to a tacky state by heating. The heat-activatable layer may be converted to its tacky state by heat prior to application to the surface of the item to be labeled. In the tacky state, the material of the heat-activatable layer may be brought into contact with the surface of the item. After contact with the surface, the heat-activatable layer may be cooled in order to form a stable bond between the heat-activatable layer and the surface of the item. 
     The combination of the heat-shrinkable layer and a heat-activatable layer facilitates removal of the label from a labeled item. This in turn may facilitate re-use or recycling of the item. The item may be e.g. a washable glass bottle. 
     The label may be adhered to the surface of the item by heating the heat-activatable layer such that it is transformed from non-tacky state to the tacky state. The label may be pressed after the heating on the surface of an item such that the heat-activatable layer is still in the tacky state. Upon subsequent cooling, a stable bond may be formed between the heat-activatable layer and the surface of the item. The heating and the pressing are preferably carried out so that the heat-shrinkable layer does not shrink to a significant degree. Thus, the label bonded to the item may still have a capability to shrink e.g. more than 20% of its original length. 
     The label may be later removed from the item by heating the label to a temperature which causes shrinking of the heat-shrinkable layer, and which also causes softening of the heat-activatable layer. In particular, the label may be removed by immersing it in a hot washing liquid. 
     When the label is heated, the heat-shrinkable layer begins to shrink generating a shear force in the bond. The bond may be simultaneously weakened due to softening of the heat-activatable adhesive such that the transverse force generated by the shrinking layer overcomes the adhesive force. Thus, shrinking of the heat-shrinkable layer may at least locally separate the label from the surface of the item. 
     Labels are typically removed from bottles by using a washing liquid. Thanks to the invention, the material layers of the label do not need to be permeable to the washing liquid. This in turn may provide a greater freedom to select the material layers of the label e.g. based on visual appearance, costs, recycling costs and/or effect on the environment. 
     The label may be used as a wash-off label. The label, the devices, and the methods described here may be used e.g. in the beverage industry. In an embodiment, recycling and/or reuse of bottles may be performed effectively, economically and in an environmentally friendly way. The label may be attached to and/or removed from a container, which may be e.g. a glass bottle, a plastic bottle, a metallic bottle, glass jar, or preserve can. 
     When using a washing liquid, it is not necessary to wait until the washing liquid penetrates through the layers of the label. Consequently, the rate of removing labels may be substantially increased. 
     The composition of the heat-activatable layer does not need to be soluble to the washing liquid. In an embodiment, the heat-activatable layer is not dissolved in the washing liquid, and the need for purifying or changing the washing liquid may be reduced. 
     The composition of the heat-shrinkable layer does not need to be soluble to the washing liquid. This may be an improvement when compared with e.g. to paper, which may become easily disintegrated in the washing liquid. In an embodiment, the heat-activatable layer is not dissolved in the washing liquid, and the need for purifying or changing the washing liquid may be reduced. Consequently, more labels may be removed by using the same amount of washing liquid. 
     The heat-activatable layer may be non-tacky at normal room temperatures. Thus, it is not necessary to use a release layer for protecting the heat-activatable layer. Thus, usage of materials needed for the labeling may be reduced. This may provide considerable savings in material and transport costs. 
     In an embodiment, visible or infrared light having a high energy density may be used for heating a thermally activatable adhesive of the bonding layer. Consequently, the total time needed for heating the label may be reduced. Thus, the overall energy consumption may be reduced, and/or the speed of attaching the labels to products may be increased. In particular, a laser beam may be used for heating the heat-activatable layer. 
     In an embodiment, the labeling rate by using the method may be e.g. more than 10000 items per hour, or even more than 50000 items per hour. The labeled items may be e.g. bottles. In particular, the labeled items may be glass bottles. 
     In an embodiment, the thickness of the carrier layer may be reduced and/or the carrier layer may be made of a material which has a lower softening temperature. Thus, the overall energy consumption may be reduced, and/or fewer materials may be consumed when producing the labels. Consequently, the production method of the labels may be more economical and/or environmentally friendly. 
     The use of a release liner may be avoided. Consequently, the amount of waste material may be reduced. The label may be stored, transported and/or used as a linerless label. 
     In an embodiment, the label may be handled and stored in a non-tacky state, and it may be converted to a tacky state just prior to bringing it into contact with the surface of the item to be labeled. This is an improvement over known pressure-sensitive labels. In particular, this is an improvement over wet-glue labels. 
     In an embodiment, the label does not need to completely surround an item. This may be an improvement over known shrink-sleeve labels. 
     In an embodiment, the label does not have visible seams. This may be an improvement over known wrap-around labels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following examples, the embodiments of the invention will be described in more detail with reference to the appended drawings, in which 
         FIG. 1  shows, in a three-dimensional view, a known label comprising a release layer, 
         FIG. 2  shows, in a three-dimensional view, attaching a label to an item, 
         FIG. 3   a  shows, in a cross-sectional side view, a label attached to an item, 
         FIG. 3   b  shows, in a cross-sectional side view, the label of  FIG. 3   a  after shrinking in hot washing liquid, 
         FIG. 3   b  shows, in a cross-sectional side view, the label of  FIG. 3   b  after it has been fully separated from the item, 
         FIG. 4  shows, in a cross-sectional side view, applying adhesive material onto a carrier sheet so as to form the label, 
         FIG. 5   a  shows, in a cross-sectional side view, a label comprising a heat-shrinkable layer and a heat-activatable layer, 
         FIG. 5   b  shows, in a cross-sectional side view, a label of  FIG. 5   a  after shrinking, 
         FIG. 6   a  shows, in a cross-sectional side view, activating the adhesive layer by heating it with light having a high intensity, 
         FIG. 6   b  shows, by way of example, temperature distribution in a label during heating, 
         FIG. 6   c  shows, by way of example, temperature distribution in the label immediately after equalization of temperatures, 
         FIG. 6   d  shows, in a cross-sectional side view, a portion of the heat-shrinkable layer and a portion of the heat-activatable layer,  FIG. 6   e  shows, in a cross-sectional side view, bringing the activated adhesive layer of the label in contact with an item, 
         FIG. 6   f  shows, by way of example, temperature distribution in a label during heating, 
         FIG. 6   g  shows, by way of example, temperature distribution in a label during heating, wherein the label has an intermediate layer, 
         FIG. 7  shows steps of manufacturing a label, for attaching the label to an item, for using the item, and for separating the materials, 
         FIG. 8   a  shows, in a cross-sectional side view, a label comprising a heat-shrinkable layer, a heat-activatable layer, and at least one passive region, 
         FIG. 8   b  shows, in a cross-sectional side view, the label of  FIG. 8   a  attached to an item, 
         FIG. 8   c  shows, in a cross-sectional side view, the label of  FIG. 8   b  after shrinking in a hot washing liquid, 
         FIG. 9  shows, in a cross-sectional side view, a label comprising a heat-shrinkable layer, a thermally insulating layer, and a heat-activatable layer, 
         FIG. 10   a  shows, in a cross-sectional side view, a label comprising a heat-shrinkable layer, a compressive strain layer, and a heat-activatable layer, 
         FIG. 10   b  shows, in a cross-sectional side view, the label of  FIG. 10   a  after shrinking, 
         FIG. 11  shows, in a cross-sectional side view, a label comprising a heat-shrinkable layer, a reflective layer, and a heat-activatable layer, 
         FIG. 12   a  shows, in a cross-sectional side view, an apparatus for attaching labels to items, 
         FIG. 12   b  shows, in three-dimensional view, the apparatus of  FIG. 12   a,    
         FIG. 13  shows, in a cross-sectional side view, changing the direction of a light beam with a reflector, 
         FIG. 14  shows, by way of example, spectral absorbance of the material layers, 
         FIG. 15  shows, by way of example, a shrinkage of a shrinkable material as a function of temperature, 
         FIG. 16  shows, by way of example, evolution of tack value for a heat-activatable adhesive, as a function of temperature, and 
         FIG. 17  shows, by way of example, evolution of tack and shrinkage as a function of temperature. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 2 , a label  100  may comprise a heat-shrinkable layer  10 , and a heat-activatable adhesive layer  20 . The label  100  may optionally comprise e.g. a graphical pattern  30  (e.g. a symbol “ABC”). 
     The heat-shrinkable layer  10  may be arranged to shrink when it is heated to a temperature which is higher than or equal to a threshold temperature T THR . 
     The heat-activatable adhesive layer  20  of the label  100  may be converted from a non-tacky state to a tacky state by heating it to a temperature, which is higher than or equal to an activation temperature T ACT . As the label may initially be non-tacky, it is not necessary to use a release layer  99 . This, in turn, may reduce the consumption of materials. 
     The layer  20  may be heated by using high-intensity light LB 1 . The light may be e.g. visible light or infrared light. The light LB 1  may be arranged to propagate as a light beam, which impinges on the layer  20 . In particular, the beam LB 1  may be a laser beam. 
     The label  100  may be attached to an item ITE 1  by bringing the activated (tacky) layer  20  into contact with the surface of the item ITE 1 . BIC denotes “bringing into contact”. 
     The item ITE 1  may be a container. In particular, the item ITE 1  may be a glass bottle suitable for containing a beverage. 
     The heating and the attaching may be carried out such that the heat-shrinkable layer  10  does not yet shrink to a significant degree. The capability of the layer  10  to shrink may be utilized later when the label is removed from the item. The label  100  may be subsequently removed from the item ITE 1  by heating the layer  10  such that it shrinks and peels at least a portion of the label  100  away from the item ITE 1 .In particular, the label  100  may be subsequently removed from the item ITE 1  by heating both layers  10 ,  20  to a temperature, which is higher than or equal to the activation temperature T ACT  and higher than or equal to the threshold temperature T THR . The material of the heat-activatable adhesive layer  20  may be selected such that when the layer  20  is heated, it may be softened such that the transverse (shear) force generated by the shrinking layer  10  can (at least locally) exceed the adhesive force between the layer  20  and the item ITE 1 . 
     The facestock layer (substrate layer) of the label  100  may comprise the heat-shrinkable layer  10 . The facestock layer (substrate layer) of the label  100  may optionally comprise one or more further layers, in addition to the heat-shrinkable layer  10 . However, the facestock layer (substrate layer) of the label  100  does not comprise the adhesive layer  20 . 
     SX, SY and SZ denote orthogonal directions. The direction SZ may be parallel to the normal of the label  100   
       FIG. 3   a  shows a label  100  attached to an item ITE 1 . The heat-activatable adhesive material is in contact with the surface of the item ITE 1 . In particular, the heat-activatable adhesive material may be in direct contact with a glass surface of the item ITE 1 . 
     Referring to  FIG. 3   b , the heat-shrinkable layer  10  of the label  10  may shrink when the layers  10 ,  20  are heated. The shrinkable layer  10  may be under tensile stress when heated to or above the threshold temperature T THR . The adhesive layer  20  may be softened and the bond between the adhesive layer  20  and the item ITE 1  may become weaker when the adhesive layer  20  is heated. In particular, a pulling force generated by the shrinkable layer  10  may pull at least one edge of the label  100  such that at least one portion of the label  100  is separated from the item ITE 1 . 
     In particular, a gap may be formed between the adhesive layer  20  and the item ITE 1 . The washing liquid LIQ 1  may subsequently penetrate into the gap, facilitating removal of the label  100 . The washing liquid LIQ 1  may also act as a lubricant and/or as an anti-adhesion agent. 
     Thanks to shrinking of the layer  10 , immersing the labeled item ITE 1  to heated washing liquid LIQ 1  may be sufficient to completely separate the label  100  from the item ITE 1 . 
     However, removal of the label  100  from the item ITE 1  may be optionally assisted by mechanical pulling, mechanical pushing, by scraping, by brushing and/or by using a liquid flow. In particular, a liquid flow may be directed to a gap formed between the label  100  and the item ITE 1  so that the overpressure of the liquid in the gap separates the label away from the item ITE 1 . 
       FIG. 3   c  shows the label  100  of  FIGS. 3   a  and  3   b  after it has been fully separated from the item ITE 1 . 
     Referring to  FIG. 4 , the label  100  may be produced e.g. by combining a heat-shrinkable layer  10  with a heat-activatable adhesive ADH 1 . For example, a water-based dispersion of a heat-activatable adhesive ADH 1  may be applied directly onto the heat-shrinkable layer  10  or onto an intermediate layer (See  FIGS. 9-11 ). The dispersion may be subsequently dried at a temperature, which is lower than the threshold temperature T THR . 
       FIG. 5   a  shows initial dimensions of the label  100 . L 10  denotes the initial length of the layer  10  in the direction SX prior to heating (i.e. before shrinking). d 1  denotes the initial thickness of the shrinkable layer  10  before shrinking. d 2  denotes the initial thickness of the adhesive layer  20  before shrinking. The thickness dl may be e.g. in the range of 0.01 mm to 1.0 mm, advantageously in the range of 0.02 to 0.2 mm. The thickness d 2  may be e.g. in the range of 0.01 mm to 1.0 mm, advantageously in the range of 0.02 to 0.2 mm. The total thickness of the label  100  may be e.g. in the range of 0.02 to 2.0 mm, advantageously in the range of 0.02 to 0.10 mm. Consumption of materials may be reduced by using small thickness d 1  and/or d 2 . 
       FIG. 5   b  shows dimensions of the label  100  after it has been shrunk by heating. L 10 S denotes the length of the layer  10  in the direction SX. AL denotes the change of length of the label  100 . The change ΔL is equal to the difference L 10 -L 10 S. The unit of the change ΔL may be e.g. a millimeter. The relative change of length is equal to ΔL/L 10 . The relative change ΔL/L 10  may also be called as the shrinkage. The unit of the relative change may be e.g. percentage (%). 
     When the layer  10  has not been (fully) shrunk, it may still have a capability to shrink. In that case, its shrinkage capability (heat-shrinkability) is equal to ΔL/L 10 . If the layer has been shrunk such that it does not have a capability to shrink any more, its shrinkage capability is zero. 
     d 1 S denotes the thickness of the shrinkable layer  10  after shrinking. d 2 S denotes the thickness of the adhesive layer  20  after shrinking. The thickness d 1 S may be greater than the thickness d 1 . The thickness d 2 S may be greater than the thickness d 2 . The increase of the thickness d 1  and/or d 2  may facilitate removal of the label. 
       FIG. 6   a  shows activating the adhesive of the heat-activatable layer  20  by heating the layer  20  with the light LB 1 . 
     The light LB 1  may be provided e.g. by a laser. In particular, a carbon dioxide (CO 2 ) laser may be used. The CO 2  laser may emit infrared light, which may have maximum spectral intensity at a wavelength, which is e.g. in the range of 9.4 μm to 10.6 μm. In particular, the carbon dioxide laser may be suitable for heating acrylic and/or polyurethane based adhesives. 
     The adhesive layer  20  may be heated such that the surface temperature T 20  of the adhesive layer  20  becomes at least momentarily higher than or equal to the activation temperature T ACT , in order to convert the adhesive into the tacky state. 
     The adhesive layer  20  may be heated such that the surface temperature T 20  of the adhesive layer  20  becomes at least momentarily higher than or equal to the activation temperature T ACT , wherein the vertically averaged temperature T 10  of the heat-shrinkable layer  10  may remain lower than the threshold temperature T THR . 
     The adhesive layer  20  may be heated such that the difference T 20 -T THR  between the surface temperature T 20  of the adhesive layer  20  and the threshold temperature T THR  is at least momentarily greater than or equal to 5° C., wherein the vertically averaged temperature T 10  of the heat-shrinkable layer may remain lower than the threshold temperature T THR . 
     The higher temperature of the adhesive layer  20 , when compared to the temperature of the shrinkable layer  10  may be attained e.g. by using one or more of the following:
         The material of the layer  10  and/or the material of the layer  20  may be selected such that the absorbance of the layer  20  is higher than the absorbance of the layer  10  at the peak wavelength of the light LB 1 .   The wavelength of the light LB 1  may be selected such that the absorbance of the layer  20  is higher than the absorbance of the layer  10  at the peak wavelength of the light LB 1 .   The layer  20  may comprise a light-absorbing dye such that the absorbance of the layer  20  is higher than the absorbance of the layer  10  at the peak wavelength of the light LB 1 .   The material of the layer  20 , the thickness of the layer  20  and/or the wavelength of the light LB 1  may be selected such that the portion of the power of the light LB 1  absorbed in the layer  20  is substantially greater than 50%, advantageously greater than 70%, and preferably greater than 90% of the initial power of the light LB 1 .   The label  100  may comprise a reflective layer  70  ( FIG. 11 ), which reflects a portion of the power of the light LB 1  back to the layer  20 . The reflective layer may be e.g. an aluminum layer. The reflective layer  70  may be positioned between the layers  10 ,  20 .   The label  100  may comprise an intermediate layer  40  ( FIG. 9 ) which decreases the heat conductivity from the layer  20  to the layer  10 .       

       FIG. 6   b  shows, by way of example, temperature distribution across the label in the thickness direction during heating with the light LB 1 . The curve T(z) may represent temperatures on the line VLIN 1  shown in  FIG. 6   d . For activation, it may be sufficient when the temperature of the exposed surface is at least momentarily higher than or equal to the activation temperature T ACT . 
     The thickness direction SZ may also be called as the vertical direction. The label  100  may have any orientation with respect to the gravity, and the “vertical” direction SZ does not need to be parallel to the direction of gravity. 
     z 21  may denote the (vertical) position coordinate of the exposed surface of the adhesive layer  20 . z 19  may denote the position coordinate of an interface  19  between the layers  10 ,  20 . z 09  may denote the position coordinate of the upper surface of the shrinkable layer  10 . z 11  may denote the position coordinate of an inner portion  11 , which is located in the middle of the shrinkable layer  10 . 
       FIG. 6   c  shows, by way of example, temperature distribution across the label after the heating has been stopped, and after the temperatures at different positions have been substantially equalized. During the equalization, thermal energy may be conducted from the adhesive layer  20  to the shrinkable layer  10 . The vertically averaged temperature of the shrinkable layer  10  may remain lower than the threshold temperature T THR . 
     The term “vertically averaged temperature” means the average value of temperatures at points of the layer  10  located on a line VLIN 1  ( FIG. 6   d ), which is perpendicular to the shrinkable layer  10 . The vertically averaged temperature is associated with a certain longitudinal and transverse position defined by the position of said line (VLIN 1 ). The directions SX and SY may define a “horizontal” plane, and the average temperature may be calculated along a “vertical” line (VLIN 1 ), which is parallel to the direction SZ. 
     The light beam LB 1  may be moved with respect to the label  100 . When heating with a light beam, the whole surface of a label  100  does not need to be activated simultaneously. As the heating may be rapid, the layers  10  and  20  may have non-zero temperature gradients in the thickness direction (SZ). For that reason, it may be relevant to consider small portions of the layers  10 ,  20 . 
       FIG. 6   d  shows in more detail a first portion  11  and a second portion  21  of the label  100 . The first portion  11  may be located within the heat-shrinkable layer  10  such that the distance to the upper surface of the layer  10  is equal to the distance to the lower surface of the layer  10  (i.e. both distances are equal to 0.5·d 1 ). To the first approximation, the temperature of the first portion may represent the vertically averaged temperature T 10  of the heat-shrinkable layer  10 . 
     The dimension of the first portion  11  and the dimension of the second portion  21  in the direction SX may be e.g. equal to d 1 . The dimension of the first portion  11  and the dimension of the second portion  21  in the directions SY may be e.g. equal to d 1 . The heat-shrinkable layer  10  and the heat-activatable layer  20  may be joined together at an interface  19 . The interface  19  may also be called as a boundary. The heat-shrinkable layer  10  may have an upper surface  9  such that the whole heat-shrinkable layer  10  is located between the upper surface  9  and the interface  19 . 
     The second portion  21  may be located at the exposed (bottom) surface of the heat-activatable layer  20 . The label  100  may become tacky when the exposed surface of the layer  20  becomes tacky. The temperature of the second portion may represent the temperature T 20  of exposed surface of the heat-activatable layer  20 . 
     The intensity of the light LB 1  when heating the adhesive layer  20  with the light LB 1  may be selected such that the vertically averaged temperature T 10  of the heat-shrinkable layer  10  remains lower than the threshold shrinking temperature T THR  of the heat-shrinkable layer  10 . In particular, the intensity of the light LB 1  and the duration of heating the adhesive layer  20  with the light LB 1  may be selected such that the vertically averaged temperature T 10  of the heat-shrinkable layer  10  remains lower than the threshold shrinking temperature T THR  of the heat-shrinkable layer  10 . 
     Heating of the layer  20  may be carried out such that a difference T 20 -T 10  between the temperature T 20  of the second portion  21  and the temperature T 10  of the first portion  11  at least instantaneously reaches a value which is greater than 5° C., wherein the temperature T 20  may at least instantaneously be greater than or equal to the activation temperature T ACT , and the temperature T 10  may remain lower than the threshold temperature T THR . 
     Heating of the layer  20  may be carried out such that the temperature T 10  of the first portion  11  remains substantially lower than the temperature T 20  of the second portion  21 , during the whole time period between heating the portion  21  and pressing the portion  21  against the item ITE 1 . 
     A difference (T 20 -T 10 ) between the temperature T 20  of the second portion  21  and the temperature T 10  of the first portion  11  may be e.g. greater than 5° C. when the temperature T 20  of the second portion  21  is equal to or higher than the activation temperature T ACT  of the adhesive of the heat-activatable layer  20 . 
     In an embodiment, heating of the layer  20  may be carried out such that the temperature T 10  of the heat-shrinkable layer is substantially lower than the temperature T 20  of the heat-activatable layer  20 , when the label  100  is brought into contact with the item ITE 1 . In an embodiment, the difference T 20 -T 10  between the temperature T 20  of the second portion  21  and the temperature T 10  of the first portion  11  may also be greater than 5° C. when the second portion  21  is brought into contact with the surface of the item ITE 1 . 
     The portions  11 ,  21  may be overlapping. The portions  11 ,  21  may be overlapping such that the transverse position of the portions  11  coincides with the transverse position of the portion  21 . The position of the portions  11 ,  21  may coincide with the position of the line VLIN 1 . The portions  11 ,  21  may be separated in the direction SZ by a non-zero distance 0.5·d 1 +d 2 . 
     The light LB 1  may be coupled into the label  100  through the layer  20  (as shown in  FIGS. 6   a  and  6   d ) or through the layer  10  (not shown). 
     Coupling of the light LB 1  to the label  100  through the layer  20  may be advantageous because in this case the layer  10  may remain cooler and the layer  10  does not need to be transparent at the wavelength of the light LB 1 . 
     On the other hand, coupling of the light LB 1  through the layer  10  to the layer  20  may be advantageous because this may allow minimizing the length of the time period between activating and contacting with the item ITE 1 . In fact, this may allow activating the layer  20  even when the layer  20  is already in contact with the surface of the item ITE 1 . In this case, the shrinkable layer  10  and all further layers may be at least locally transparent at the peak wavelength of the light LB 1 . The layer  10  may be opaque for visible light but transparent for infrared light LB 1 . The layer  10  may be transparent at visible and infrared light. 
     Referring to  FIG. 6   e , the label  100  may be brought into contact with an item ITE 1  after the adhesive of the heat-activatable layer  20  has been activated by heat. 
     The label  100  may be pressed against the item ITE 1  by using a pressure generated by a force F 1 . 
     The label  100  may be pressed onto the surface of the item ITE 1  by holding the label  100  with a holding member  310 , and by holding the item ITE 1  with a holding member  320 . 
     Once activated, the adhesive layer  20  may remain tacky during a certain time period even after the layer  20  has been cooled to a temperature, which is slightly lower than the activation temperature T ACT . Said time period is called as the hot tack life. The hot tack life may be e.g. in the range of 0.1 s to 100 s. The label may be brought into contact with the item ITE 1  within the hot tack life. 
     Heat may be rapidly conducted from the heated adhesive layer  20  to the shrinkable layer  10 . Consequently, the temperatures T 10  and T 20  may be rapidly equalized after exposure to the heating light LB 1  has been stopped. The time period for equalization of the temperatures may be e.g. in the range of 100 μs to 100 ms. The maximum value of the temperature T 10  during the heating and the initial value of the temperature T 20  just before the heating may be selected such that the vertically averaged temperature T 10  of the shrinkable layer  10  remains lower than the threshold temperature T THR  during and after the equalization. Thanks to the hot tack life, the adhesive layer  20  may remain tacky even after the equalization of the temperatures T 10 , T 20  has taken place. Thus, a reliable bond between the label  100  and the item ITE 1  may be formed even after the surface temperature of the adhesive layer  20  has decreased to a value lower than the activation temperature T ACT . 
       FIG. 6   b  showed a situation where the optical depth of the activatable layer  20  is smaller than the geometrical thickness d 2  of the layer  20  (at the wavelength of the light LB 1 ). Consequently, the intensity of the light LB 1  at the interface  19  may be substantially reduced when compared with the intensity of light LB 1  impinging on the surface portion  21 . 
       FIG. 6   f  shows, by way of example, a vertical temperature distribution in a label  100  during heating in a situation where the optical depth of the layer  20  is greater than the geometrical thickness d 2  of the layer  20 . Consequently, a region of the layer  20  near the interface  19  may be directly heated by the light LB 1 . Heat may be conducted from the layer  20  to the layer  10  such that the temperature of a thin region of the layer  10  in the vicinity of the interface  19  may exceed the threshold temperature T THR . However, the vertically averaged temperature of the layer  10  may still remain lower than the threshold temperature T THR . The material of the shrinkable layer  10  may be selected such that the optical absorbance of the shrinkable layer  10  is small, in order to minimize direct heating of the layer  10  by the light LB 1 . 
       FIG. 6   g  shows, by way of example, a vertical temperature distribution in a label  100  which has an intermediate thermally insulating layer (see e.g.  FIG. 9 ). The intermediate layer may protect the shrinkable layer  10  from heat conducted from the adhesive layer  20 . z 41  may denote the coordinate of a boundary between the shrinkable layer  10  and the thermally insulating intermediate layer. z 42  may denote the coordinate of a boundary between the adhesive layer  20  and the thermally insulating layer. 
       FIG. 7  shows phases of a lifecycle of a label  100 . The label  100  may be produced, the label may be attached to an item to form a combination, the labeled item may be used, and the label may be separated from the item at the end of the lifecycle of the label. 
     The production of the label  100  may comprise a label forming step  810 . The label  100  may be formed e.g. by applying an adhesive substance onto a heat-shrinkable layer  10 . The adhesive substance may be e.g. a water-based dispersion. The adhesive substance may be applied e.g. by roller-coating, reverse-gravure, curtain-coating, spraying, dip-coating, and/or with a brush. Water may be evaporated from the dispersion by using e.g. hot air jets or infra-red heaters. The temperature of the layer  10  may be kept below the threshold temperature T THR  during the drying. 
     The label  100  may comprise one or more intermediate layers  40 ,  60 ,  70  located between the layers  10 ,  20  (See  FIGS. 9-11 ). The adhesive substance may be applied onto directly onto the layer  10  or onto an intermediate layer. 
     A layer  10  comprising a heat-activatable material may be joined to a heat-shrinkable layer  10 . 
     Several labels  100  may be initially produced as a web  101 . The resulting web  101  may be wound into reels and supplied e.g. to a printer (e.g. for printing graphical patterns) for further processing. The web  101  may be stored and/or transported as a roll. The web  101  may be cut to form individual labels  100  at a later stage. 
     The heat-activatable layer  20  is preferably non-tacky in the normal room temperature (at temperatures below T ACT ). Thus, the layer  20  of the label  100  or of the web  101  does not need to be protected with a release liner (release layer  99 ). 
     A combination of an item ITE 1  and the label  100  may be formed by a method comprising a heating step  820  and an attaching step  830 . The exposed heat-activatable layer  20  may be activated by heating it with visible or infrared light having a high intensity. 
     In the attaching step  830 , at least one portion of the heat-activatable layer  20  may be brought into contact with the surface of the item ITE 1 . The label  100  may be pressed against the item ITE 1 . 
     The (optional) using phase may comprise a using step  840 , where the combination of the item ITE 1  and the label  100  attached to the item ITE 1  may be e.g. transported, stored, used for containing a beverage, delivered to a consumer, and/or collected back from a consumer. The item ITE 1  may be e.g. a glass bottle, which is used to contain a beverage during a time period, which in the range of 1 hour to 1 year. 
     The separating phase may comprise a separating step  850  where the label  100  is heated to a temperature T WASH , which is higher than or equal to the threshold shrinking temperature T THR  of the heat-shrinkable layer  10 . Advantageously, the temperature T WASH  is also higher than or equal to the activation temperature T ACT  of the heat-activatable layer  20 . 
     In particular, the label  100  may be heated by immersing it into a heated washing liquid LIQ 1 . 
     The item ITE 1  may be optionally re-used after the label  100  has been removed. For example, a new label  100  may be attached to the item ITE 1  and/or the item ITE 1  may be re-filled with a new foodstuff or beverage. 
     The label  100  may be deformed or damaged in the removal step  850 . However, the materials of the label  100  may be optionally recycled and utilized again. 
     Substantially the whole (one-sided) surface of the label  100  may be covered with a heat-activatable layer  20 . The thickness d 1  and/or d 2  may be spatially constant. 
     Referring to  FIG. 8   a , the thickness d 1  of the shrinkable layer  10 , the thickness d 2  of the adhesive layer  20  and/or the thickness of an optional intermediate layer may be spatially varying in order to facilitate removal of the label  100 . In particular, the thickness d 2  may vary spatially between zero and a maximum value, as shown in  FIG. 8   a.    
     The adhesive may be applied as a single meandering stripe or a several separate stripes or spots such that one or more passive regions  22  remain between activatable regions  20   a,    20   b.  Thus, the heat-activatable adhesive may cover substantially less than 100% of the bottom side of the label  100 . 
     For example, the heat-activatable adhesive may cover an area which is in the range of 10% to 90% of the total one-sided area of the label  100 . 
     Leaving one or more passive regions  22  between the activatable regions  20   a,    20   b  may provide one or more of the following advantages:
         consumption of the adhesive may be reduced,   the weight of the label  100  may be reduced,   the time and optical energy (of the light LB 1 ) needed to activate the adhesive may be reduced,   the risk of premature shrinking may be reduced,   separation of the label may be facilitated   greater shrinkage may be attained, because a smaller force is needed to compress the activatable layer  20 .       

     A spatially uniform adhesive layer or a patterned adhesive layer may be activated by using spatially uniform intensity distribution or spatially varying intensity distribution. 
     Substantially less than 100% of the bottom area of the label  100  may be heated by the light LB 1 . For example, the heated area may be in the range of 10% to 50% of the bottom area of the label  100 , wherein 90% to 50% of the area is not directly heated. One or more stationary or moving light beams LB 1  may be arranged to provide e.g. activated stripes or spots by locally heating a substantially continuous layer  20 . Activated stripes or spots may also be provided by a mask, which locally prevents activation of certain areas of the layer  20 . 
     The one or more light beams LB 1  may provide a heating pattern that leaves certain one or more non-activated and thus non-adherent portions. The non-activated portions may form channels between the label and the item such that the washing liquid may subsequently penetrate quickly under the label from the peripheral regions of the label. This may accelerate removal of the label, in particular when the washing liquid LIQ 1  reacts with the layer  20  or dissolves the layer  20 . The permeability of one or more layers of the label may be low for the washing liquid, and the channels may accelerate wetting of the space between the label  100  and the item ITE 1 . 
     Referring to  FIG. 8   b , the combination of the item ITE 1  and the label  100  may be immersed in a washing liquid LIQ 1  in order to remove the label  100  at the end of the lifecycle of the label  100 . The passive regions may form channels or cavities which facilitate penetration of the washing liquid LIQ 1  to the space between the label  100  and the item ITE 1 . The liquid LIQ 1  may rather easily moisten the surface of the item ITE 1  in the vicinity of the passive region  22 . In other words, a film of the liquid LIQ 1  may be adhered to the surface of the item ITE 1  in the vicinity of the passive region  22 . 
       FIG. 8   c  shows the label  100  after shrinking. The liquid LIQ 1  may rather easily moisten the surface of the item ITE 1  in the vicinity of the passive region  22 . In other words, a film of the liquid LIQ 1  may be adhered to the surface of the item ITE 1  in the vicinity of the passive region  22 . When the label  100  shrinks and the portion  20   a  begins to slide over the surface of the item ITE 1 , the liquid film may remain in place, and the liquid film may act as a lubricant and as an anti-adhesion agent, which prevents re-attachment of the portion  20   a  back to the surface of the item ITE 1 . 
     The heat-activatable adhesive may be directly in contact with the heat-shrinkable material. In this case, the use of different types of materials may be minimized. On the other hand, the label  100  may comprise one or more additional layers. 
     Referring to  FIG. 9 , the label  100  may comprise a heat barrier layer  40  located between the layers  10 ,  20 . The layer  40  may be arranged to protect the layer  10  from heat during the activation of the layer  20 . 
     The heat barrier layer  40  may be thermally insulating. The layer  40  may be a thermally insulating layer  40 . Thermal conductivity of the insulating layer  40  may be e.g. smaller than 0.1 W·m −1 K −1 . The layer  40  may comprise e.g. polymer foam. 
     The material of the intermediate layer  40  may also be selected to have a high heat capacity at a temperature, which is lower than the threshold temperature T THR . A high capacity may be provided e.g. by a phase change (e.g. melting, softening and/or chemical reaction). The heat capacity may be e.g. greater than 2000 J/K − kg −1  (J denotes Joule, K denotes Kelvin and kg denotes kilogram). 
     A portion of the heat-activatable layer  20  may itself operate as a heat barrier. 
     For example, the absorbance of the layer  20  may be so high and the irradiation time may be so short that only a thin film on the surface of the heat-activatable layer  20  is heated, wherein the remaining portion of the layer  20  located under the surface may operate as heat barrier. Temperature-dependent phase changes in the layer  20  may effectively reduce conduction of heat to the shrinkable layer  10 . Thus, the use of different materials may be minimized and the manufacturing of the label may be simplified. 
     Referring to  FIG. 10   a , the label  100  may comprise a counter-force layer  60  located between the layers  10 ,  20 . The shrinkage capability of the layer  60  may be substantially smaller than the shrinkage capability of the layer  10  at temperatures higher than or equal to the activation temperature T ACT . Consequently, heating of the layer  10  together with the layer  60  may cause bending and/or buckling of the label  100  as shown in  FIG. 10   b , in order to facilitate removal of the label  100 . The layer  60  may comprise e.g. paper or polymer. The polymer may be pre-shrunk and/or non-stretched such that it exhibits low shrinkage when heated. 
     Referring to  FIG. 11 , the label  100  may comprise a reflective layer  70  located between the layers  10 ,  20 . The layer  70  may consist of e.g. metallic aluminum. The reflective layer  70  may prevent coupling of the light LB 1  into the heat-shrinkable layer  10  and/or it may increase the intensity propagating in the heat-activatable layer  20 . 
       FIG. 12   a  shows an apparatus  500  arranged to attach a label  100  to an item ITE 1 . In particular, the apparatus  500  may be arranged to attach labels to a plurality of items at a high rate. 
     The label  100  may be held by a holding member  310 . The holding member  310  may be e.g. a vacuum roll or a vacuum belt. The item ITE 1  may held by a second member  320  (see e.g.  FIG. 6   e ). 
     The member  310  may be moved with respect to the member  320 , and/or the member  320  may be moved with respect to the member  310  in order to press the label  100  against the item ITE 1 . In particular, the members  310 ,  320  may be rotating members. The members  310 ,  320  may be arranged to move in synchronization with each other. The members  310 ,  320  may be arranged to rotate in synchronization with each other. 
     A light source  200  may be arranged to provide light LB 1 , which activates the adhesive of the heat-activatable layer  20  by heating. The light source  200  may comprise a light emitting unit  210  and a directing unit  220 . The directing unit  220  may provide a light beam LB 1  by changing the direction of a primary light beam LB 0  and/or by changing the spatial properties of the primary light beam LB 0 . The primary light beam LB 0  may be generated by the generating unit  210 . In particular, the generating unit  210  may be a laser, and the light source  200  may be arranged to provide one or more laser beams LB 1 . 
     The light LB 1  may impinge on the layer  20  at a (laser) spot SP 1 . 
     The directing unit  220  may comprise e.g. optics arranged to provide a suitable size and shape for the spot SP 1 . For example, the directing unit  220  may comprise optics arranged to distribute the power of the light beam LB 1  to an area, whose dimension in the direction SY is close to the width of the label  100 , in order to heat the entire width of the label. 
     For example, the directing unit  220  may comprise optics, which is arranged provide a scanning light beam LB 1 . The location of the spot SP 1  may be moved e.g. in the direction SY in order to heat the entire width of the label. 
     The label  100  may be subsequently attached to an item ITE 1  by bringing the activated surface of the layer  20  into contact with the item ITE 1  and by pressing the label  100  against the item ITE 1 . The label and the item may be pressed together with a force F 1 . 
     Advantageously, the apparatus  500  may be arranged to operate such the heated and exposed (tacky) surface of the heat-activatable layer  20  is not touched by any other surface before it is pressed against the item ITE 1 . 
     The item ITE 1  may be kept at a temperature, which is lower than the threshold temperature T THR  of the heat-shrinkable layer  10 . Consequently, pressing the label  100  against the item ITE 1  may facilitate cooling the heat-activatable layer  20  such that the risk of premature shrinking may be further reduced or avoided. 
     After a first item ITE 1  has been labeled with a first label  100 , the first item held by the member  320  may be replaced with a second item. The second item may be subsequently labeled with a second label, by using the apparatus  500 . 
     The member  310  may be optionally rotated about an axis AX 1 . The item ITE 1  may be optionally rotated about an axis AX 2 . 
     The item ITE 1  may be optionally preheated to a temperature, which is higher than the normal room temperature 25° C., in order to improve andesion For example, the item ITE 1  may be preheated to a temperature, which is in the range of 40° C. to 60° C. The apparatus  500  may comprise a heating unit for pre-heating the item ITE 1 . 
     The label  100  may be held against the member  310  e.g. by a pressure difference. The member  310  may comprise one or more holes (not shown) and/or the surface may be porous for extracting gas from a space between the label  100  and surface of the member  310 . The gas may be extracted from said space e.g. by a pump (not shown), which creates a region of low pressure. 
     The labels  100  may be supplied separately or as a web  101 . The web  101  may be fed at a (constant or varying) velocity v 1 . The apparatus  500  may optionally comprise e.g. one or more blades  374  to separate an individual label  100  from a web  101 . The labels may be cut also by a laser beam. 
     The web  101  may be guided e.g. by one or more auxiliary (optional) rollers  371 ,  372 . 
     The apparatus  500  may comprise e.g. pre-heater  350  to preheat a label  100 . Preheating may allow the reduction of the intensity of the light LB 1  and/or preheating may allow a high rate of attaching labels to items. 
     The apparatus  500  may comprise a control unit  400  arranged to control operation of the apparatus  500 . 
     The apparatus may comprise a memory MEM 1  for storing operating parameters of the apparatus. The operating parameters may comprise e.g. intensity of the light LB 1 , velocity of a label  100  with respect to a laser spot SP 1 , rotation speed of the member  310  (when the member  310  is a roll), preheat temperature of a label  100 , temperature of the holding member, and temperature of the item ITE 1 . 
     The apparatus may comprise a memory MEM 2  for storing computer program code which when executed by a processor is for controlling the operation of the apparatus  500  according to the invention. 
     The heat-activatable layer  20  may be heated to a temperature, which in a predetermined range. If the temperature is too low, a reliable bond will not be formed. If the temperature is too high, the layer  20  may be damaged and/or the heat-shrinkable layer  10  will begin to shrink. The state of the heat-activatable layer  20  may be monitored optically based on a change in the optical properties. For example, the state of the layer  20  may be monitored by monitoring light scattered from the surface of the bonding layer  20 . For example, the surface may be smoother in the tacky state than in the non-tacky state. In the non-tacky state, the layer  20  may comprise microscopic grains or cracks, which may substantially disappear when the layer  20  is converted into the tacky state. Consequently, the surface may cause more diffuse reflection in the non-tacky state than in the tacky state. The activation time and/or power levels may be adjusted based on the monitored state of the layer  20 . The activation time and/or power levels may be adjusted by using closed-loop control, in particular by using PID control. 
       FIG. 12   b  shows, in a three-dimensional view, the apparatus of  FIG. 12   a.    
       FIG. 13  shows how the distance L TR  between the (laser) spot SP 1  and the point PFC of first contact may be reduced by using beam-directing optics M 1 . Consequently, the time delay between heating and attaching may be reduced. 
     Referring to  FIG. 14 , the materials of the shrinkable layer  10  and/or the adhesive layer  20  may be selected such that the spectral absorbance of the adhesive layer  20  is higher than the spectral absorbance of the shrinkable layer  20  at the peak wavelength λ P  of the light LB 1 . Consequently, the shrinkable layer  20  may be heated less than the adhesive layer  20 . The peak wavelength λ P  may be in the visible region or in the infrared region of electromagnetic radiation. 
     A dye may be added to the adhesive layer  20  in order to modify its spectral properties. For example, (black) carbon powder may be added to the adhesive layer  20 . 
     However, it is not necessary to select the spectral properties according to  FIG. 14 . The thickness of the layer  20  and/or the material of the layer  20  may be selected such that most of the initial energy of the beam LB 1  is absorbed already in the layer  20 , before the beam LB 1  impinges on the shrinkable layer  10 . For example, the layer  20  may have so high absorbance at the wavelength of the beam LB 1  that more than 70%, advantageously more than 90% of the initial energy of the beam LB 1  may be absorbed in the adhesive layer  20 . 
       FIG. 15  shows typical (relative) shrinkage ΔL/L 0  of heat-shrinkable material as a function of temperature. ΔL denotes a change of dimension (e.g. length), and L 0  denotes initial dimension (length). The threshold temperature T THR  may be defined to be a minimum temperature where the (relative) shrinkage ΔL/L 0  is greater than or equal to 5%. The threshold temperature T THR  may be defined to be a minimum temperature where the (relative) shrinkage ΔL/L 0  reaches 5%, when the temperature of the layer  10  is increased from a reference temperature of 25° C. 
     The shrinkable layer  10  may have residual shrinkage capability even after the layer  10  has been heated to the threshold temperature T THR . The residual shrinkage capability may be utilized when the label is later removed by heating it in hot washing liquid LIQ 1 . 
     The (relative) shrinkage ΔL/L 0  of the layer  10 , when heated from the threshold temperature T THR  to the activation temperature T ACT  may be e.g. greater than or equal to 5%, advantageously greater than or equal to 10%, and preferably greater than or equal to 20%. 
     The derivative of the curve of  FIG. 15  may be called as the shrink rate. The maximum shrink rate at a temperature between the threshold temperature T THR  and the activation temperature T ACT  may be e.g. greater than or equal to 1%/° C., advantageously greater than or equal to 2%/° C., and preferably greater than or equal to 3%/° C. 
     The heat-shrinkable material may have an “on-set temperature” T OS , which may be defined to be a minimum temperature where the (relative) shrinkage ΔL/L 0  is greater than or equal to 2%, when the temperature of the layer  10  is increased. The on-set temperature T OS  of the shrinkable layer  10  may be e.g. greater than or equal to 50° C. in order to minimize the risk of premature shrinking. 
     Advantageously, the intensity of the light LB 1  may be selected such that the vertically averaged temperature T 10  of the heat-shrinkable layer  10  remains lower than the on-set temperature The. This may reduce shrinking of the label  100  during the attaching, to provide a visually pleasant appearance for the labeled item ITE 1 . 
     In an embodiment, amorphous adhesive material may be mixed with one or more other polymers such that the resulting composition is substantially non-tacky at the room temperature (i.e. at 25° C.). The resulting composition may be used as the adhesive layer  20  of the label  100 , wherein said composition may become tacky when heated. In particular, the adhesive layer  20  may comprise amorphous polyurethane polymer blended with acrylic polymer and/or with styrene-acrylic polymer. 
       FIG. 16  shows typical behavior of tack values as a function of temperature. At a low temperature, the material of the heat-activatable layer  20  may be in the non-tacky state, and it may have a low tack value. At a high temperature, the heat-activatable layer may be in the tacky state, and it may have high tack value. 
     The activation temperature T ACT  may denote a temperature where the tack value is equal to 2.0 N, when the temperature of the layer  20  is increased. The activation temperature T ACT  may denote a temperature where the tack value reaches the value 2.0 N, when the temperature of the layer  20  is increased. The tack value may be measured by the standardized FINAT test method no. 9 (FTM9) “Quick Stick” tack measurement (loop tack), FINAT, Den Haag, Netherlands; (Class 1: test for adhesive tapes). Said loop tack test comprises measuring a force, which is needed to separate a loop strip from a base plate, such that the contact area is 25 mm×25 mm. The loop strip may be formed e.g. by cutting the test strip from a label  100 . 
     During the activation, the surface temperature may at least momentarily reach or exceed the activation temperature T ACT , Thus, the tack value utilized when attaching the label may be greater than or equal to 2.0 N. For a more reliable bond between the label and the item, the surface temperature may at least momentarily reach exceed the activation temperature T ACT  such that the momentary tack value is e.g. greater than 3 N, greater than 5 N, or even greater than 10 N. 
     In some cases, the loop tack value may depend on properties of the layer  20 . 
     The activation temperature T ACT  may also be defined based on a probe tack value determined by the test method defined in the standard ASTM D2979, herein called as the probe test method. The probe tack value may be less dependent on the properties of the layer  20  than the loop tack value. The probe test method involves using a 5 mm diameter circular probe, and measuring the force needed to separate the probe from the adhesive layer. 
     The activation temperature T ACT  may denote a temperature where the probe tack value is equal to 0.4 N/mm 2 . 
     During the activation, the surface temperature may at least momentarily reach or exceed the activation temperature T ACT , Thus, the tack value utilized when attaching the label may be greater than or equal to 0.4 N/mm 2 . For a more reliable bond between the label and the item, the surface temperature may at least momentarily reach exceed the activation temperature T ACT  such that the momentary tack value is e.g. greater than 0.6 N/mm 2 , greater than 1.0 N/mm 2 , or even greater than 2.0 N/mm 2 . 
     The adhesive material may exhibit an increase in the tack value also at temperatures below the activation temperature T ACT . This may be harmful when a plurality of labels are stored in a stack or in a roll. F BLOC  may denote a (minimum) tack value, which may cause problematic sticking of an adhesive layer of a first label  100  to the face surface of a second label  100 . The sticking may be considered to be problematic e.g. when it causes an increased risk of damaging the labels when the labels are pulled apart. The tack value F BLOC  may be reached at a blocking temperature T BLOC . Labels  100  stored in a roll may be “blocked” if the storage temperature is higher than or equal to the blocking temperature T BLOC . The material of the activatable layer  20  may be selected such that the blocking temperature T BLOC  is higher than or equal to e.g. 50° C. 
       FIG. 17  shows, by way of example, the shrinkage and the tack as a function of temperature. Prior attaching to the item ITE 1 , the label  100  may be stored e.g. at temperatures below the on-set temperature T OS  and below the blocking temperature T BLOC  in order to reduce the risk of premature shrinking and to reduce the risk of premature sticking. 
     When the label  100  is attached to an item ITE 1 , the adhesive of the layer  20  may be activated by rapidly increasing the surface temperature of the layer  20  so that it is temporarily higher than or equal to the activation temperature T ACT . The activation may be carried out by using the intense light LB 1  such that the temperature of the shrinkable layer remains lower than the threshold temperature T THR . This ensures that the label  100  may still have residual shrinkage capability, which can be utilized to facilitate removing the label  100  from the item ITE 1 . The shrinkage ΔL/L 0  of the layer  10 , when heated to the washing temperature T WASH  may be e.g. greater than or equal to 10%. Before removal, the temperature of the shrinkable layer  10  has not exceeded the threshold temperature T THR . The shrinkage ΔL/L 0  associated with the threshold temperature T THR  may be e.g. 5%. Thus, a residual shrinkage ΔL R /L 0 , which can be used to assist removal when the label  100  is heated to the washing temperature T WASH , may be e.g. greater than or equal to 5%, advantageously greater than or equal to 10%, and preferably greater than or equal to 20%. 
     The materials of the layers  10 ,  20  may be selected such that the activation temperature T ACT  is lower than or equal to the washing temperature T WASH , and such that the threshold temperature T THR  is lower than the activation temperature T ACT . For a heat-activatable adhesive material, the activation temperature T ACT  and the blocking temperature T BLOC  may be coupled together such that selecting a high activation temperature T ACT  may also provide an elevated blocking temperature T BLOC . The elevated blocking temperature T BLOC  may minimize the risk of premature adhesion to other labels. Furthermore, the material of the layer  10  may be selected such that heating the label  100  to the washing temperature T WASH  greater than or equal to the activation temperature T ACT  ensures sufficient residual shrinkage ΔL R /L 0  (e.g. greater than or equal to 5%), in order to facilitate removal of the label. 
     The label  100  may be attached to an item e.g. in order to visually show information associated with the item. The information may comprise e.g. trademark of a manufacturer, advertising information, price information, or operating instructions. 
     The length of the label  100  (in direction SX) may be e.g. in the range of 1 cm to 20 cm, and the width of the label  100  (in direction SY) may be e.g. in the range of 0.5 cm to 10 cm. 
     The labeled item ITE 1  may be a re-washable item, which can be labeled with a second label after removal of a first label. 
     The item ITE 1  may be e.g. a recyclable or reusable container selected from a group consisting of a glass bottle, a plastic bottle, a plastic container, a glass container and a metallic container. The item ITE 1  may be a re-washable container. 
     The item ITE 1  may comprise or consist of e.g. glass, polyethylene terephthalate (PET) polycarbonate and/or stainless steel. 
     The item ITE 1  may be a glass container, which can withstand several washing cycles in hot washing liquid without significant damage. The item ITE 1  may be glass container for containing an edible substance. The glass bottle ITE 1  may contain a beverage, e.g. milk, cream, beer, soft drink. The item ITE 1  may be a glass jar comprising a food. 
     The threshold shrinking temperature T THR  may be e.g. lower than 95° C., which allows removal of the label  100  in aqueous washing liquid LIQ 1  (at normal atmospheric pressure 100 kPa). 
     On the other hand It may be advantageous to select the threshold temperature T THR  to be high enough such that the label  100  is not accidentally removed e.g. when the labeled items is left in direct sunshine. 
     The threshold temperature T THR  may be e.g. higher than or equal to 60° C., higher than or equal to 70° C., or higher than or equal to 80° C. 
     The bond formed between the adhesive layer  20  and the item ITE 1  should be soft at temperatures greater than or equal to the activation temperature T ACT . 
     Advantageously, the adhesive layer  20  may be soft or it may become softer at temperatures greater than or equal to the activation temperature T ACT . so that the transverse shear force generated by the shrinking layer  10  overcomes the force generated by the bond between the adhesive layer  20  and the item ITE 1 . 
     Activation of the adhesive layer  20  by the heat may be a reversible process. Heating of the heat-activatable layer  20  may reversibly transform the surface of the layer  20  from a non-tacky state to a tacky state. Subsequent cooling of the heat-activatable layer  20  may reversibly transform the surface of the layer  20  from a tacky state to a non-tacky state. A second heating of the heat-activatable layer  20  may reversibly transform the surface of the layer  20  from a non-tacky state to a tacky state, again. 
     Manufacturing of the label  100  may comprise drying an adhesive layer  20 , which comprises a water-based dispersion. Manufacturing of the label  100  may comprise evaporating a solvent from an adhesive layer comprising solvent-based adhesive, said solvent being different from water. The drying and/or evaporation may comprise heating the label  100  to a temperature, which is lower than the threshold temperature T THR . Manufacturing of the label  100  may comprise curing a solid adhesive by atmospheric moisture before heating the layer  20  to a temperature higher than or equal to the activation temperature T ACT . 
     The composition of the adhesive layer  20  may be selected such that is not cured when heated to a temperature higher than or equal to the activation temperature T ACT . 
     Advantageously, the activation temperature T ACT  is higher than or equal to the threshold temperature T THR . Thus, the heated layer  10  will be under tensile strain and contraction of the label  100  in the hot washing liquid may take place almost immediately after the label  100  has been heated to the activation temperature T ACT . The difference T ACT -T THR  between the activation temperature T ACT  and the threshold temperature T THR  may be e.g. in the range of 5 to 30° C. 
     Selecting the activation temperature T ACT  to be higher than or equal to the threshold temperature T THR . may allow using a more environmentally friendly combination of materials in the heat-activatable layer  20  and in the heat-shrinkable layer  10 . This may allow larger variations in the properties of the heat-activatable layer  20  and in the heat-shrinkable layer  10 . This may allow using cheaper materials in the heat-activatable layer  20  and in the heat-shrinkable layer  10 . This may minimize the risk of premature activation of the adhesive layer  20  when a plurality of labels are stored for a long period in a roll or in a stack. The temperature of the labels may exceed 40° C., and sometimes even exceed 50° C. when stored and/or transported in a container, which is exposed to direct sunshine. 
     Heat-shrinkability is a quantitative property of a material. When the material has a heat-shrinkability which is equal to ΔL/L 10 , this means that the length of a body consisting of said material will change by an amount ΔL when the temperature of the body is increased from 25° C. to 100° C., the shrinking of the body is not mechanically restricted, and the initial length of the body (at 25° C.) is L 10 . The heat-shrinkability may also be called as the shrinkage capability. 
     The shrinkage capability ΔL/L 10  of the material of the layer  10  in at least one direction (e.g. in the direction SX) may be e.g. greater than 10%, advantageously greater than 15%, and preferably greater than 20%. 
     The heat-shrinkable layer  10  may be mono-axially shrinkable or bi-axially shrinkable. 
     Typically, a higher shrinkage may be attained by mono-axial shrinking. The (mono-axial) shrinkage capability ΔL/L 10  (see  FIG. 5   b ) may be e.g. greater than 15%, advantageously greater than 20%, and preferably greater than 30%. 
     The heat-shrinkable layer  10  may be arranged to shrink substantially mono-axially in a first direction (e.g. in the direction SX), wherein the shrinkage in the second perpendicular direction (e.g. in the direction SY) may be smaller than 50% of the shrinkage in the first direction. 
     The label may be removed from the item by exposing the labeled item to a hot washing liquid LIQ 1  such that the label is heated to a temperature which is higher than or equal to the activation temperature T ACT . This causes softening of the adhesive layer  20 . Furthermore, when the activation temperature T ACT  is higher than the threshold temperature T THR , and when the shrinkable layer  10  still has at least the residual capability to shrink, the heating by the washing liquid LIQ 1  may cause contraction of the layer  10  so as to facilitate removal of the label  100  from the item ITE 1 . 
     The activation temperature T ACT  may be greater than the threshold temperature T THR , wherein the activation temperature T ACT  may be e.g. lower than or equal to 63° C., lower than or equal to 77° C., lower than or equal to 80° C., lower than or equal to 90° C., lower than or equal to 100° C., lower than or equal to 110° C., lower than or equal to 120° C. 
     The typical washing temperature T WASH  used in North America may be e.g. about 66° C. When the activation temperature T ACT  is selected to be lower than or equal to 63° C., this may allow removal of the label  100  by using a washing temperature T WASH  of 66° C. The typical washing temperature T WASH  used in Europe may be e.g. about 80° C. When the activation temperature T ACT  is selected to be lower than or equal to 77° C., this may allow removal of the label  100  by using a washing temperature T WASH  of 80° C. 
     A large difference T ACT -T THR  between the activation temperature T ACT  and the threshold temperature T THR  may provide large shrinkage of the layer  10  when exposed to a washing temperature T WASH , which is higher than or equal to the activation temperature T ACT . On the other hand, the threshold temperature T THR  may be selected to be higher than or equal to e.g. 58° C. in order to reduce the risk of premature shrinking. For the typical North American washing conditions, the difference T ACT -T THR  may be e.g. about 5° C. (=63° C.-58° C.). For the typical European washing conditions, the difference T ACT -T THR  may be e.g. about 19° C. (=77° C.-58° C.). 
     The threshold temperature T THR  may be e.g. in the range of 58 to 75° C., and the difference T ACT -T THR  between the activation temperature T ACT  and the threshold temperature T THR  may be e.g. in the range of 5 to 30° C. 
     When the label  100  is attached to the item ITE 1 , the adhesive layer  20  may be heated such that the heat-shrinkable layer  10  does not shrink to a significant degree. In particular, the label  100  may be heated such that the shrinkage ΔL/L 10  which actually takes place is smaller than 5%, preferably smaller than 2%. 
     The adhesive material of the heat-activatable layer  20  may be selected e.g. such that the heat-activatable layer  20  is not tacky at temperatures below 50° C. The composition of the heat-activatable layer  20  is advantageously selected such that the layer  20  does not exhibit tackiness and/or a blocking tendency at temperatures below 50° C. Thus, the adhesive layer  20  does not need to be protected by a release layer during storage and/or transportation. The adhesive layer  20  does not need to be protected by a release layer even when a plurality of labels are stored and/or transported in a roll. Advantageously, the label  100  does not comprise a release layer. Advantageously, a first label of a roll of labels does not comprise a release layer arranged to be between the first label and a second label of said roll. 
     The heat-shrinkable layer  10  may comprise e.g. material selected from the following group: polyethylene terephthalate (PET), glykol-modified polyethylene terephtalate (PETG) polyvinylchloride (PVC), polyester, polystyrene, polyethylene, polypropene, polyoefin, cyclicolefin copolymer, and polyactic acid (PLA). The layer  10  may comprise two or more materials selected from this group. 
     The heat-activatable adhesive layer  20  may comprise e.g. material selected from the following group: polyurethane, acrylic, styrenic polymer, block-copolymer rubber, styrene-isoprene-styrene, styrene-butadiene, olefin-block copolymer, natural rubber, acrylic copolymer, hydrocarbon resin, and rosin ester. The layer  10  may comprise two or more materials selected from this group. 
     In particular, the heat-activatable adhesive layer  20  may comprise e.g. 
     polyurethane adhesive. The heat-shrinkable layer  10  may comprise e.g. polyethylene terephthalate (PET). 
     The graphical pattern  30  of the label  100  may be optionally protected with a transparent protective layer (not shown). The label may optionally comprise e.g. a thermally insulating layer  60  ( FIG. 9 ) and/or a reflective layer  70  ( FIG. 11 ). 
     A typical bottle recycling system may be arranged to use hot washing liquid LIQ 1  for removing the labels  100 . The layers  10 ,  20  may be heated e.g. by immersing the combination of the item ITE 1  and the label  100  in a washing liquid LIQ 1   FIG. 3   b ). 
     However, the layers  10 ,  20  may be heated also by heating in an oven or by to heating with a hot gas stream, instead or in addition to the washing liquid. 
     The heat-shrinkable layer  10  may comprise mono-axially oriented or biaxially oriented polymer film, which may comprise e.g. polyester, in particular polyethylene terephthalate (PET), polyvinylchloride and/or polypropylene. Typically, higher shrinkage and consequently slightly better removal properties may be obtained by using mono-axially oriented polymer film. 
     The layer  20  may comprise e.g. thermally activatable polyurethane. The adhesive layer  20  may comprise amorphous polyurethane polymer blended with acrylic polymer and/or with styrene-acrylic polymer such that the layer  20  is not tacky at the room temperature. After applying and drying the adhesive to a substrate (e.g. to the layer  10 ), a non-tacky activatable adhesive film may be first obtained. The activatable film may become tacky by heating the film to a temperature which is higher than or equal to the activation temperature. In particular, the polyurethane may comprise polyester segments and/or polyether segments, and the activation may comprise softening of the segments. 
     At temperatures below T ACT , the layer  20  may be in a crystalline state, and the adhesive may be in the non-tacky state. At elevated temperatures, the layer  20  may become tacky. When the activation temperature exceeds an upper limit, the tack value may start to decrease due increased softening of the layer  20 . 
     The time period during which the layer  20  has sufficient tackiness for bonding is called the hot-tack life. During this period, the adhesive may be tacky, and it may be joined to the surface of the item ITE 1 . 
     The hot-tack life may range e.g. from seconds to several minutes depending on the structure and chemical composition of the layer  20 . 
     High initial bond strength may be obtained after a short time, by cooling of the adhesive film and reversible crystallization of polymer segments. 
     A property of heat-activatable polyurethane adhesives comprising the segments may be that, because of their high molecular weight and segmented polymer structure, the layer  20  may be mechanically stable at temperatures which are higher than the decrystallization (softening/melting) temperature of the segments. Thus, the layer  20  may exhibit thermoplastic flow to a considerable extent only at temperatures which are significantly higher than the minimum activation temperature T ACT . 
     Acrylic and polyurethane adhesives may be thermally activated when the molecules of the adhesive gain enough thermal energy to overcome a threshold energy of activation. Thermal energy may induce a phase transition from the solid and tack free crystalline molecular structure of the adhesive to an amorphous tacky state. 
     The adhesive layer  20  may comprise an adhesive composition containing at least one acrylate polymer and at least one amorphous polyurethane or polyurethane-polyurea polymer. The adhesive composition may be applied onto the one or more other layers  10 ,  40 ,  60 ,  70  as an aqueous dispersion. The glass transition temperature of the acrylate polymer may be e.g. in the range of 50 to 90° C., and the glass transition temperature of the polyurethane or polyurethane-polyurea polymer may be e.g. in the range of −50 to 10° C. Adhesive compositions containing acrylate polymer and amorphous polyurethane or polyurethane-polyurea polymer have been described e.g. in EP2395064A1. 
     The heat-activatable layer  20  will be in contact with the surface of the item ITE 1 . The composition of the heat-activatable layer  20  is advantageously selected such that it may be removed cleanly from the surface during the wash-off process so that it will not significantly stain or leave deposits on the surface. 
     The label  100  may further comprise additives like fillers. The label  100  may further comprise additional layers, such as intermediate layers implemented between the heat-shrinkable layer  10  and the heat-activatable layer  20 . The top side of the heat-shrinkable layer  10  may be optionally protected with one or more protective layers. The additional layers may be arranged to improve the label properties, functionality or appearance. Graphical patterns  30  may be printed on one or more of said layers e.g. in order to provide a visual effect and/or in order to display information. 
     The label  100  may be attached to the item ITE 1  such that the label  100  does not completely surround the item ITE 1 . The label  100  may be attached to the item ITE 1  such that the label  100  does not form a closed loop. In an embodiment, the label  100  does not form a closed loop. In an embodiment, the heat-shrinkable material of the label  100  does not form a closed loop. 
     The label  100  does not need to be a sleeve. Thus, for example, a large item may be labeled with a small label. 
     The label  100  may be attached to the item ITE 1  such that the label  100  is not under tensile stress during cooling of the heat-activatable layer  20 . 
     A typical method used for removing labels in North America may comprise e.g. using a washing liquid LIQ 1 , which contains 4.0 to 4.5% (by weight) sodium hydroxide dissolved in water, typically heated to a temperature T WASH  of 66° C. (i.e. about 150° F.). 
     The material of the heat-shrinkable layer  10  and the material of the heat-activatable layer  20  may be selected such that shrinking and softening of the bond can take place when the label is heated to a temperature higher than 60° C. The temperature of a washing liquid LIQ 1  used for removing the label  100  may be e.g. higher than 60° C. The washing liquid LIQ 1  may be e.g. an alkaline solution heated to a temperature, which is in the range of 60° C. to 85° C. The washing liquid LIQ1 may contain e.g. 0.5% to 10% (by weight) sodium hydroxide dissolved in water. A typical method for removing labels in Europe may comprise e.g. using a washing liquid LIQ 1 , which contains 1.5 to 2.0% (by weight) sodium hydroxide dissolved in water, typically heated to a temperature of about 80° C. Thus, the washing liquid LIQ 1  may be e.g. an alkaline solution heated to a temperature T WASH , which is in the range of 75° C. to 85° C. The washing liquid LIQ 1  may contain e.g. 0.5% to 10% (by weight) sodium hydroxide dissolved in water. 
     The washing liquid LIQ 1  used in the beverage industry may typically be alkaline. It may be advantageous to select the materials of the label such that the label can be easily removed by using the composition and temperature of the washing liquid, which are typically used in the beverage industry. 
     However, the washing liquid LIQ 1  may also be substantially neutral. For example, the pH of the washing liquid LIQ 1  may be e.g. in the range of 5 to 9. This may be applicable e.g. for removing a label from a re-usable aluminum container, which might be damaged in an alkaline solution. 
     The recycling of the materials of the label  100  may be facilitated if chemical composition of the heat-activatable layer  20  and/or the chemical composition of the washing liquid LIQ 1  are selected such that the heat-activatable layer  20  is not dissolved in the heated washing liquid LIQ 1 . 
     The material of the adhesive layer  20  may be selected such that it is not significantly dissolved and/or chemically bound in the washing liquid LIQ 1 . Thus, the need to purify the washing liquid LIQ 1  may be reduced. 
     The materials of the adhesive layer  20  may also be selected such that transformation from the non-tacky state to a tacky state is an irreversible process. In this case, the time delay between heating and contact with the item may be long. 
     When forming the adhesive layer  20 , e.g. after applying a dispersion on a substrate (e.g. on the layer  10 ), the dispersion may be dried at temperatures low enough not to cause softening and/or melting of plasticizers. Therefore, the evaporation of water from the dispersion may produce a substantially non-tacky adhesive layer. Activation may be performed using a high temperature, which may cause the plasticizers to melt and make the adhesive permanently tacky. This transformation relates to lowering the glass transition temperature Tg of the adhesive. The materials of the layer  20  may be selected such that the plasticizers do not crystallize again even after lowering the temperature again and therefore this temperature switching from a non-tacky state to a tacky state may be an irreversible process. In particular, the transformation of an acrylate adhesive may be irreversible. After thermal activation, the adhesive may remain tacky even after cooling. 
     The heating may take place so fast that the temperature of the heat-shrinkable layer  10  remains lower than the threshold temperature T THR . The light source  200  may be a laser, which is arranged to provide one or more laser beams LB 1 . The light source may be arranged to operate such that the intensity of the light LB 1  is higher than a predetermined limit. 
     However, if the intensity is too high, the heat-activatable layer  20  may be damaged e.g. due to oxidation, chemical decomposition and/or ablation. The intensity may be kept below a second predetermined limit in order to avoid permanently damaging the heat-activatable layer  20 . 
     The light source  200  providing the light LB 1  may be e.g. a diode laser, by a carbon dioxide laser, by an argon-ion laser, or by a Nd:YAG-laser. One or more (laser) light beams LB 1  may be used to heat the layer  20 . 
     The intensity of the light beam LB 1  may be higher than a predetermined limit such that the duration of heating can be kept shorter than a second predetermined limit, e.g. shorter than 100 ms, advantageously shorter than 20 ms. In case of a very thin label  100 , the duration of heating may be kept e.g. shorter than 10 ms or even shorter than 1 ms (10 −3  s). The intensity of the light beam LB 1  at the exposed surface of the activatable layer  20  may be e.g. higher than 100 W/cm 2 , advantageously higher than 500 W/cm 2 . For example, the optical power of a laser beam LB 1  may be e.g. in the range of 10 W to 200 W, and the optical power of said laser beam LB 1  may be focused to a laser spot SP 1  such that the intensity of the beam LB 1  at the exposed surface of the activatable layer  20  is higher than 100 W/cm 2 , advantageously higher than 500 W/cm 2 . 
     The laser beam LB 1  may be a continuous wave (CW) beam or a pulsed beam. The heating rate may also be controlled by adjusting the pulse frequency and/or duty cycle of the laser pulses. 
     A laser beam LB 1  may rapidly activate the layer  20  such that the activated area is accurately defined. The laser beam LB 1  may also have a peak wavelength, which matches with the spectral absorbance of the layer  20 . 
     In an embodiment, the light LB 1  may also be provided by a tungsten halogen lamp or by an infrared-emitting rod. 
     The whole (bottom) area of a label  100  may be heated substantially simultaneously. Alternatively, different portions of the label  100  may be heated at different times. 
     The labels  100  or the web  101  may be printed with any type of print process such as UV-flexo, UV-letterpress, water-based-flexo, solvent-based flexo, gravure, offset, screenprocess, thermal-transfer, direct-thermal hot- or cold-foil stamping. After printing, the labels may be die-cut and supplied in pre-cut form. The labels may have an arbitrary shape and/or design format. 
     The labels  100  may be supplied in rolls to an application point, where they may be cut using a laser or a die-cutting blade, and they may be transferred to e.g. a vacuum drum ( FIG. 12   a ) or vacuum belt. The label  100  may be picked and transferred to desired location by using suction generated by the vacuum drum or belt. 
     The combination of the item ITE 1  and the label  100  may be formed by heating a portion  21  of the heat-activatable layer  20  of the label  100  by visible or infrared light LB 1  so that at least a portion of the surface of the heat-activatable layer  20  is converted from a non-tacky state to a tacky state, wherein the intensity of the light LB 1  may be selected such that the temperature T 10  of a portion  11  of the heat-shrinkable layer  10  remains lower than the threshold shrinking temperature T THR  of the heat-shrinkable layer  10  during the heating by the light LB 1 . Said portion  11  may be located within the heat-shrinkable layer  10  such that the distance to the upper surface of the layer  10  is equal to the distance to the lower surface of the layer  10 . 
     The item ITE 1  may be attached to the item ITE 1  such that the label  100  does not form a closed loop around the item ITE 1 . The item ITE 1  may be attached to the item ITE 1  such that the label  100  does not form a closed loop around the item ITE 1  during activation of the heat-activatable layer  20  of the label  100  with the light LB 1 . The item ITE 1  may be attached to the item ITE 1  such that the heat-shrinkable material of the label  100  does not form a closed loop around the item ITE 1 . The item ITE 1  may be attached to the item ITE 1  such that the heat-shrinkable material of the label  100  does not form a closed loop around the item ITE 1  during activation of the heat-activatable layer  20  of the label  100  with the light LB 1 . The heat-activatable layer  20  may be activated by heating with the light LB 1  such that the label  100  does not form a closed loop around the item ITE 1  when the layer  20  is in the tacky state. The combination of the label  100  and the item ITE 1  may be formed such that the label  100  does not form a closed loop around the item ITE 1  after a stable bond between the heat-activatable layer  20  and the surface of the item has been formed. The combination of the label  100  and the item ITE 1  may be formed such that the label  100  does not form a closed loop around the item ITE 1  when substantially the whole bottom area of the label  100  is in contact with the item ITE 1 . The combination of the label  100  and the item ITE 1  may be formed such that the label  100  does not form a closed loop around the item ITE 1  after the whole bottom area of the label  100  has been brought into contact with the item ITE 1 . 
     Various aspects of the invention are illustrated by the following examples: 
     EXAMPLE 1 
     A method for attaching a label ( 100 ) to an item (ITE 1 ), the label ( 100 ) comprising a heat-shrinkable layer ( 10 ) and a heat-activatable layer ( 20 ), the method comprising:
         heating a portion ( 21 ) of the heat-activatable layer ( 20 ) by visible or infrared light (LB 1 ) so that at least a portion of the surface of the heat-activatable layer ( 20 ) is converted from a non-tacky state to a tacky state, and   attaching the label ( 100 ) to the item (ITE 1 ) when the surface of the heat-activatable layer ( 20 ) is in the tacky state,
 
wherein the intensity of the light (LB 1 ) is selected such that the temperature (T 10 ) of a portion ( 11 ) of the heat-shrinkable layer ( 10 ) remains lower than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ).
       

     EXAMPLE 2 
     The method of claim  1  wherein the shrinkage capability of the heat-shrinkable layer ( 10 ) of the label ( 100 ) is greater than 20%. 
     EXAMPLE 3 
     The method of claim  1  or  2  wherein the light (LB 1 ) is a laser beam provided by a carbon dioxide laser ( 200 ). 
     EXAMPLE 4 
     The method according to any of the claims  1  to  3  wherein the length of a time period between heating and bringing the portion ( 21 ) into contact with the item (ITE 1 ) is shorter than 1 s, preferably shorter than 0.1 s. 
     EXAMPLE 5 
     The method according to any of the claims  1  to  4  wherein the activation temperature (T ACT ) of the heat-activatable layer ( 20 ) is higher than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ). 
     EXAMPLE 6 
     The method according to any of the claims  1  to  5  further comprising separating the label ( 100 ) from the item (ITE 1 ) by heating the label ( 100 ) to a temperature (T WASH ), which is higher than or equal to the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ), and which is higher than or equal to the activation temperature (T ACT ) of the heat-activatable layer ( 20 ). 
     EXAMPLE 7 
     A label ( 100 ) comprising a heat-shrinkable layer ( 10 ) and a heat-activatable layer ( 20 ), wherein the activation temperature (T ACT ) of the heat-activatable layer ( 20 ) is higher than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ). 
     EXAMPLE 8 
     The label ( 100 ) of claim  7  wherein the shrinkage capability of the heat-shrinkable layer ( 10 ) of the label ( 100 ) is greater than 20%. 
     EXAMPLE 9 
     The label ( 100 ) of claim  7  or  8  wherein the heat-activatable layer ( 20 ) comprises a polyurethane adhesive, and the heat-shrinkable layer ( 10 ) comprises polyethylene terephthalate (PET), glykol-modified polyethylene terephtalate (PETG) polyvinylchloride (PVC), polyester, polystyrene, polyethylene, polypropene, polyoefin, cyclicolefin copolymer, and/or polyactic acid (PLA). 
     EXAMPLE 10 
     The label ( 100 ) according to any of the claims  7  to  9  comprising forming at least two heat-activatable regions ( 20   a,    20   b ) such that a permanently passive region ( 22 ) remains between said two regions ( 20   a ,  20   b ). 
     EXAMPLE 11 
     A method of manufacturing a label ( 100 ), the method comprising:
         applying a dispersion onto a structure comprising a heat-shrinkable layer ( 10 ), and   drying the dispersion so as to form a solid non-tacky layer ( 20 ), which comprises a heat-activatable adhesive (ADH 1 ),
 
wherein the activation temperature (T ACT ) of the heat-activatable layer ( 20 ) is higher than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ).
       

     EXAMPLE 12 
     A combination of an item (ITE 1 ) and label ( 100 ) attached to the item (ITE 1 ), the label ( 100 ) comprising a heat-shrinkable layer ( 10 ) and a heat-activatable layer ( 20 ), wherein the activation temperature (T ACT ) of the heat-activatable layer ( 20 ) is higher than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ). 
     EXAMPLE 13 
     The combination of claim  12  wherein the shrinkage capability of the heat-shrinkable layer ( 10 ) of the label ( 100 ) is greater than 20%. 
     EXAMPLE 14 
     The combination of claim  11  or  12  wherein the item (ITE 1 ) is a glass bottle. 
     EXAMPLE 15 
     A method of separating a label ( 100 ) from an item (ITE 1 ), the label ( 100 ) comprising a heat-shrinkable layer ( 10 ) and a heat-activatable layer ( 20 ), the method comprising:
         heating the label ( 100 ) to a temperature (T WASH ), which is higher than or equal to the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ), and which is higher than or equal to the activation temperature (T ACT ) of the heat-activatable layer ( 20 ).       

     EXAMPLE 16 
     The method of claim  15  wherein the activation temperature (T ACT ) of the heat-activatable layer ( 20 ) is higher than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ). 
     EXAMPLE 17 
     The method of claim  15  or  16  comprising immersing the label ( 100 ) in a heated washing liquid (LIQ 1 ). 
     EXAMPLE 18 
     An apparatus ( 500 ) for attaching a label ( 100 ) to an item (ITE 1 ), the label ( 100 ) comprising a heat-shrinkable layer ( 10 ) and a heat-activatable layer ( 20 ), the apparatus comprising:
         a light source ( 200 ) arranged to heat a portion ( 21 ) of the heat-activatable layer ( 20 ) by visible or infrared light (LB 1 ) so as to transform the surface of the heat-activatable layer ( 20 ) from a non-tacky state to a tacky state, and   a holding member ( 310 ,  320 ) arranged to attach said portion ( 21 ) to the item (ITE 1 ) when the surface of the heat-activatable layer ( 20 ) is in the tacky state,
 
wherein the light source ( 200 ) and the holding member ( 310 ,  320 ) are arranged to operate such that a temperature (T 10 ) of a portion ( 11 ) of the heat-shrinkable layer ( 10 ) remains lower than the threshold shrinking temperature (T THR ) of the heat-shrinkable layer ( 10 ) during the time period between the heating and the attaching.
       

     For the person skilled in the art, it will be clear that modifications and variations of the devices and the methods according to the present invention are perceivable. The drawings are schematic. The particular embodiments described above with reference to the accompanying drawings are illustrative only and not meant to limit the scope of the invention, which is defined by the appended claims.