WO1997028974A1

WO1997028974A1 - Transfer label

Info

Publication number: WO1997028974A1
Application number: PCT/EP1997/000642
Authority: WO
Inventors: Hans-Peter Ast
Original assignee: Zweckform Etikettiertechnik Gmbh
Priority date: 1996-02-12
Filing date: 1997-02-12
Publication date: 1997-08-14
Also published as: DE59701652D1; HK1015325A1; DE29602430U1; EP0888225B1; EP0888225A1; ES2146979T3

Abstract

The invention concerns a transfer label comprising: a carrier material layer (1); a printing layer (5) which is detachably disposed on the carrier material layer (1) and can be affixed to an object by adhesive (7); and a protective layer (3) which is disposed between the carrier material layer (1) and the printing layer (5) and can be detached from the carrier material layer (1). The protective layer takes the form of a substantially non-plasticizeable protective film (3) which sticks directly to the carrier material layer (1) by adhesion yet can be detached substantially independently of the label temperature and is made of a completely polymerized material.

Description

Transfer label

description

The invention relates to a transfer label with a carrier layer, a detachably arranged on the carrier material layer, attachable to an object by means of adhesive attachable print layer and a protective layer arranged between the carrier material layer and the print layer, detachable from the carrier material layer.

A label of this type is known from WO90 / 05088. There, a release material layer is provided between a high-gloss coated carrier material and the layers to be transferred to the substrate, which layer is activated by heat when the label is transferred to the object in such a way that it enables the layers to be transferred to be detached from the carrier material. If this separating material layer is missing, the carrier material cannot be removed from the still heated label. After the label has been transferred to the object, an additional protective layer is applied, and this is then hardened under UV radiation. This post-curing process requires a relatively long running distance and is mechanically complex. This applies in particular if the objects are beverage glass bottles which are coated with a plastic layer to reduce friction in the jogging sections of bottle filling systems, which layer is to be protected from UV radiation.

A transfer label is known from US Pat. No. 4,529,624, the outer layer of which is connected to the carrier material via a paraffin layer to be melted during the transfer. The paraffin layer remains on the label after the transfer, with residues possibly remaining on the carrier. The transfer is therefore not always complete. The paraffin layer is smoothed by subsequent flame treatment and is therefore more transparent and shiny and less visible.

The object of the invention is therefore to provide a transfer label which can be transferred to an object without residue and does not require any aftertreatment.

To achieve the object, a transfer label of the type mentioned is proposed, in which the protective layer is made from a fully polymerized material and is essentially non-plasticizable, adheres directly to the backing material layer by adhesion, but is essentially detachable independently of the temperature of the label Material of existing protective film is formed.

This eliminates the need for a heat-releasable connection layer between the protective film and the carrier material, so that after the label has been transferred to the object, no release material or wax layers can remain on the label. Because the scratch-resistant protective film is already part of the label, the additional application of a protective layer on the label adhering to the object is unnecessary. The label can be produced in one pass in "in-line" mode. The peeling off of the carrier material layer shortly before or during or shortly after the label has been stuck onto the object is independent of the temperature of the label. If the adhesive is a thermo-activatable adhesive and if the label is applied to an appropriately heated object with heating, the backing material can be removed immediately. The same advantage is obtained with a label that is to be transferred cold.

Due to the absence of the separating material layer, a particularly precise printing of the color layers can be achieved. The separating plane between the carrier material and protective film is particularly precisely defined, so that the label is deliberately removed from the carrier remove material and apply smooth. The interaction of the adjoining surfaces of protective film and carrier material is based on adhesive forces, such as electrostatic forces. After the label has been separated from the carrier material and transferred to the object, the exposed surface of the protective film remains non-adhesive, regardless of the temperature. The protective film is hard and scratch-resistant.

The carrier material layer and the protective film preferably form a pair of materials with a holding force which is essentially independent of the temperature. The carrier material layer can consist of several sub-layers. The carrier material layer preferably consists of polypropylene, at least on the side facing the protective film, the side of the protective film which is preferably untreated. The thickness of the carrier material can be 20 to 100 μm, preferably 35 to 60 μm. In order that the combination of carrier material layer and transfer labels can be easily unwound from a roll, the side of the carrier material layer that repels from the protective film can be provided with a non-stick coating, for example siliconized or provided with a release lacquer.

The protective film is preferably formed from lacquer hardening under radiation, in particular cationically cold-crosslinked lacquer hardening under ultraviolet light. Cold-curing, cationic UV varnish hardens under UV radiation. The chain reaction begins with UV light. Crosslinking and curing take place completely even without further UV exposure. The protective film remains non-sticky after curing.

Alternatively, it is also possible to use a radical UV varnish which hardens as long as UV rays act on it. If the radiation is incomplete, however, the lacquer can sometimes remain sticky, so that the next layer in the label assembly does not adhere properly to the protective film and there is skin formation (so-called skinning).

A lacquer hardening by electron beams is also possible.

The varnish used should be heat stable so that it does not change its properties under the influence of the heat application during transmission. The protective film consists of non-resinous, non-sticky varnishes.

The protective film is thinner than the carrier material layer, preferably by a factor of 2 to a factor of 100, particularly preferably 10 to 20. The protective film is preferably 1 to 10 μm thick, particularly preferably 2.5 to 5 μm. The thinner the protective film, the lower the thermal energy required for label transfer and the lower the thermal load on the object. This is of particular concern if the object is a beverage glass bottle coated with plastic that is easy to slide.

To absorb distortions as well as crushing and tensile loads when transferring the label to the object, the protective film can be stretchable, with an elongation at break in the range from about 50 to 400%, preferably from about 100 to 300%, preferably 150 to 250%, preferably about 200%.

A protective film is also a PE or PP protective layer (polyethylene or polypropylene), which does not adhere to the substrate layer by adhesion. The protective film can be co-extruded with the carrier material layer. The print layers can consist of solvent-based lacquers. They are preferably water-insoluble, heat-resistant, color-fast, tonal value-stable, opaque and heat-stable.

Depending on the materials used, the print layer and

Protective film, it can happen that the print layers adhere poorly directly to the protective film, for example if solution medium-containing layers are to be printed on a cationically UV-cured protective film. In these cases, it is advisable to print a suitable primer layer on the protective film before printing on the printing layers. The primer layer acts as an adhesion promoter. The primer layer can have one layer and, in addition to its adhesion-promoting properties, can also act as a barrier against the immigration of solvents from the printed layer into the protective film. The primer layer can have an adhesive layer on the protective film side and an additional barrier layer thereon, or an adhesive layer, a barrier layer and a further adhesive layer starting from the protective film, onto which the printed layers are then printed.

The stretchability of the printed layer and possibly the primer layer, the barrier layer and the adhesive layer (s) can be adapted to that of the protective film, the stretchability of the individual layers decreasing from the adhesive side to the protective film side. This allows the label to be transferred onto the object without damage and at the same time with a high protective effect of the protective film.

The adhesive layer can be formed from a pressure-sensitive adhesive, a thermo-activatable adhesive that only sticks permanently after exposure to heat, or a thermosensitive adhesive that is only sticky during heating.

A thermo-activatable adhesive can be a two-component adhesive, one component or a reaction medium of which is located in microcapsules, which burst due to the action of heat and then the two components are mixed and this results in a curing reaction. The use of such two-component adhesives when sticking labels onto objects is independent of the construction of the label.

When sticking the label onto the object, Using a thermally activated adhesive, the object must be preheated as precisely as possible to the temperature at which the adhesive layer is to be heated during application. The temperature should be in a range in which a friction-reducing plastic coating of a glass bottle to be labeled is not damaged.

The label is produced by printing the respective layers one after the other onto the backing material layer, the protective film and the overprinting or color layers and possibly the primer being printed onto the backing material layer with essentially the same contour. The protective film can overlap the edges of the layers of paint to protect them. The adhesive layer is also printed with the same contour as the colored layers and the protective film.

A preferred manufacturing process includes the following

Steps:

1) providing a carrier material layer,

2) contoured printing of a protective layer consisting of material to be crosslinked directly onto the carrier material layer,

3) polymerisation of the protective layer through to an essentially non-plasticizable protective film, which adheres to the carrier material layer in a detachable manner regardless of the temperature of the label,

4) contoured printing of at least one printing layer on the protective film, and

5) contoured printing of adhesive onto the printing layer. When the label is transferred to the object, dietjr looks as if it was printed and not as if it had been given a flat label.

Preferred embodiments will now be described with reference to the accompanying drawings.

Fig. 1 shows schematically in section a first embodiment of a transfer label; and

Fig. 2 shows schematically in section a second embodiment of a transfer label.

1. A carrier material 1, which can be formed in multiple layers from coextruded polypropylene or polyethylene on a paper carrier and can have a thickness of 20 to 100 μm, has a low-adhesion surface la of polypropylene low surface energy. In coextrusion, several thermoplastic materials are extruded together. Multilayer films are produced which, compared to simple films, have the advantage that the individual layers can have different functions (e.g. atte outer layer for good printing or inner layers with an adhesive surface for low blocking effect).

The polypropylene or polyethylene is not pretreated so that it has a low surface energy or surface tension of, for example, 28-32 mN / m. A contoured, preferably prepolymerized, protective layer is printed onto this surface, which is not very adhesive. The protective layer is then polymerized through to a protective film which can no longer be plasticized by dissolving its cohesion. The surfaces 1a of the carrier material 1 and 3a of the protective film lying directly on top of one another adhere to one another through physical adhesion, for example electrostatic forces. As a result of the adhesion, the protective film 3 adheres only slightly to the carrier material 1 and does not stick relatively firmly, as is the case with pressure-sensitive adhesives. The adhesive effect is independent of temperature. The protective film 3 preferably consists of cationically cold-crosslinking lacquer which cures under UV radiation, which starts a chain reaction by UV light and cures completely and remains non-adhesive after curing.

The thickness of the protective film is 1 to 10 μm, preferably 2.5 to 2 μm. The protective film for absorbing tensile and squeezing forces and distortions during the transfer process to the object is preferably elastic, for example with an extensibility in the range from approximately 50 to 400%, approximately 100 to 300%, in particular approximately 150 to 250%, preferably approximately 200 % according to DIN 53455 (elongation at break of the protective film material). The basic composition of the UV-curing protective film preferably contains acrylic acid polymers, about 40% by weight of polyurethane-acrylate polymer mixture, about 20% by weight of monofunctional octyl decyl acrylate and about 35% by weight. % Tri-propylene glycol di-acrylate (TPGDA), and the rest of additives.

Alternatively, it can be a UV-curing radical lacquer, the curing of which takes place as long as UV radiation acts. This lacquer can also have the extensibility values mentioned above. Lacquers which cure under electron radiation and polyethylene or polypropylene layers which adhere to the carrier material in the above-mentioned interaction are also suitable. For this purpose, material pairings of carrier material and protective film come into consideration:

EVA / PE = ethylene vinyl acetate / polyethylene EVA / PP = ethylene vinyl acetate / polypropylene

WPVC / PE = soft polyvinyl chloride / polyethylene

WPVC / PP = soft polyvinyl chloride / polypropylene.

On the protective film 3, essentially following its contours, a color layer 5 of preferably solvent-based lacquer is printed. Like the protective film, this lacquer is heat-stable. Furthermore, the color layer is water-insoluble lent, heat-resistant, colourfast, tonal value and opaque.

Depending on the application, a cold-adhesive or heat-activatable adhesive layer 7 is printed on the ink layer 5 with the same shape as the ink layer 5 and protective film 3. The thickness of the adhesive layer 7 is 2 to 40 μm. The elasticity of the color layer 5 is preferably matched to that of the protective film and is in particular greater than that of the protective film.

To transfer the label from the carrier material 1 to the surface of an object G, the object is preferably preheated to the adhesive temperature of the adhesive layer 7. Then the carrier material with the adhesive label thereon is pressed onto the object by means of a hot plate or heat roller, so that the adhesive layer 7 becomes sticky and with it the contoured ink layer 5 and protective film layer 3 stick to the object. The carrier material is then pulled off and removed from the protective film 3 in the parting plane labeled T in FIG. 1. The backing material can be removed - for example when using a transfer roller - also shortly before the label is attached to the article, or, if the label has to be massaged onto the article, also after the application. The extensibility of the carrier tape material is significantly less than that of the label layers 3, 5 and 7, preferably 50-150%.

The surface 3a of the protective film 3 touching the carrier layer 1 before the transfer now forms the outer surface of the finished label, the UV-hardened protective film layer 3 protecting the label against scratching. As a result of the adhesive connection, neither the support material 1 nor the protective film 3 is sticky after the separation of the support material 1.

The contours of the protective film can slightly overlap those of the coloring and adhesive layer, so that The protective film also covers and protects the contour edges of the paint and adhesive layer.

2 shows a further embodiment of a transfer label. Layers corresponding to the above embodiment are provided with the same reference numbers, increased by the number 100. A protective film 103 made of cationically cold-curing UV varnish is printed on the carrier material 101, their adjoining surfaces 101a and 103a being temperature-sensitive by adhesion - stick together independently.

A primer layer 109 is printed on the protective film 103, which at the same time can form a barrier against solvents emerging from the color layers to be printed thereon. Depending on the material pairing of protective film and color layers, the primer layer can have several partial layers, for example an adhesion-promoting layer 109a on the protection film 103, a barrier layer 109b against migrating solvents and, in turn, an adhesion-promoting layer 109c for the color layers 105 printed thereon. In the embodiment shown there are five Color layers 105a to 105e are shown. Of course, any other number of color layers is also conceivable. As above, the color layers are solvent-based paints that are heat-stable, water-insoluble, color-fast, tonal value-stable and opaque.

The extensibility of the primer layer (s) 109a-c and here the color layer (s) 105a-e can each be adapted to that of the protective film 103. In particular, the extensibility of the primer layer (s) lies between that of the protective film 103 and that of the color layer (s) 105a-e.

A thermo-activatable adhesive layer 107, which can be designed as in the first embodiment, is then printed onto the last ink layer 105e with the same shape as the protective film 103, primer layer 109 and the at least one ink layer 105. The carrier material 101 has on its side facing away from the protective film 103 an adhesive layer 101b made of silicone or release lacquer, which prevents the adhesive layer 107 of the next layer of labels in the roll from being wound on the carrier tape material 101 having a large number of labels adhered to it Carrier tape material 101 sticks. The extensibility of the carrier tape material 101 is significantly less than that of the label layers 103, 105, 109 and is approximately 50-150%.

The transfer of the label from the carrier material 101 to the object G is carried out in the same manner as described above, the carrier tape material 101 being after the transfer without residue along the parting plane T between the two surfaces 101a of the carrier material 101 and the surface 103a of the protective film separates.

Claims

Expectations

1. Transfer label, with a carrier material layer (1), a printable layer (5) detachably arranged on the carrier material layer (1), attachable to an object by means of adhesive (7), and one between the carrier material layer (1) and the print layer ( 5) arranged, from the carrier material layer (1) detachable protective layer (3), characterized in that the protective layer as substantially non-plasticizable, directly adhering to the carrier material layer (1) by adhesion, but essentially independently of the temperature of the label detachable protective film (3) made of a polymerized material.

2. Transfer label according to claim 1, characterized in that the carrier material layer (1) and the protective film (3) form a pair of materials with a substantially temperature-independent predetermined holding force.

3. Transfer label according to claim 1 or 2, characterized in that the carrier material layer (1) at least on the side facing the protective film (3) consists of poly propylene, the side of the protective film (3) carrying (la) is preferably untreated .

4. Transfer label according to one of the preceding claims, characterized in that the protective film (3) is formed from radiation-curing lacquer, in particular cationically cold-crosslinking UV lacquer.

5. Transfer label according to one of the preceding claims, characterized in that the at least one imprint layer (5) is formed from solvent-based lacquer is.

6. Transfer label according to one of the preceding claims, characterized in that the at least one printing layer (105) adheres to the protective film (103) by means of a primer layer (109).

7. Transferetiektt according to claim 6, characterized in that the primer layer (109) at least one Haftvermitt- o telnde partial layer (109a, 109c) and a migration of

Has solvents in the protective film (103) preventing barrier layer (109b).

8. Transfer label according to one of the preceding claims, s characterized in that the adhesive layer (7) is made of pressure-sensitive adhesive or a glue that is only permanently adhesive or thermally activated after a single heat action, or a thermosensitive glue that only sticks during heating. 0

9. Transfer label according to one of the preceding claims, characterized in that the protective film (3), the at least one imprint layer (5) and the adhesive layer (7) are printed on the carrier material layer essentially one after the other 5 with the same contour.

10. Transfer label according to one of the preceding claims, characterized in that the protective film (3) is stretchable, in particular an extensibility in the range from about 0 50 to 400%, preferably about 100 to 300%, preferably 150 to 250%, particularly preferably 200 %, having.

11. Transfer label according to one of the preceding claims, characterized in that the protective film (3) in its 5 basic composition contains acrylic acid polymers, preferably approximately 40% polyurethane-acrylate polymer mixture, approximately 20% monofunctional octyl decyl acrylate and about 35% Tri-propylene glycol di-acrylate and the rest additive.

12. Transfer label according to one of the preceding claims, characterized in that the extensibility of the printed layer (5, 105) and optionally the extensibility of the primer layer (109) is adapted to the extensibility of the protective film (3, 103).

13. Transfer label according to one of the preceding claims, characterized in that the respective extensibility of the label layers to be transferred (3, 5, 7; 103, 109, 105, 107) decreases from the adhesive side to the protective layer side.

14. Transfer label according to one of the preceding claims, characterized in that the extensibility of the carrier material layer (1, 101) is less than the extensibility of the label layers to be transferred (3, 5, 7; 103, 109, 105, 107) .

15. A method for producing a transfer label, in particular according to claim 1, characterized by the following steps:

1) providing a carrier material layer (1),

2) contoured printing of a protective layer consisting of material to be crosslinked directly onto the carrier material layer (1),

3) Polymerization of the protective layer through to an essentially non-plasticizable protective film

(3) which adheres to the carrier material layer (1) detachably from the carrier material layer (1) essentially independently of the temperature of the label, 4) contoured printing of at least one printing layer (5) on the protective film (3), and

5) contoured printing of adhesive (7) on the printing layer (5).