Adhesive tape and its use

[0001] The subject of the invention is an adhesive tape and its use, especially for the dynamic exchange of rolls with wound non-polarized material in the form of a tape.

[0002] When using tape material (paper, films, nonwovens, etc.), dynamic roller replacement is the method used to replace an old, almost worn roll by a new roller, without the need to stop high-speed machines. With this type of dynamic roller replacement, adhesive tapes are often used to connect the end of an old tape to the beginning of a new tape.

[0003] In the film and nonwovens processing industry, dynamic roll replacement is performed for materials with non-polarized surfaces in two different ways.

[0004] According to the first method, the double-sided adhesive tapes in a preferred arrangement (usually straight or w or v-shaped) are glued manually at the beginning of the tape of a new roll and the tape protruding from the adhesive tape is cut off. The beginning of the tape on a new roll is glued using a fastening label (or "retainer") on the underlying roll of the new roll to prevent unwinding of the tape when the new roll accelerates to the peripheral speed of the old roll. The disadvantage of this method is that the preparation of rolls is very labor intensive and gluing can only be carried out by highly qualified employees. In addition, this method does not always give the desired results because the adhesive joints made in this way are relatively thick due to the overlapping of tape material, fixing labels and adhesive tape. For this reason, with thin elastic bands, it may happen that at the beginning of the new bands, due to the occurrence of an air stream in the opposite direction, the bands may be erected, which generally leads to improper sticking of the bands.

[0005] In a second known method, one-sided adhesive tape is glued onto the overlap and straight under the free end of the upper roll of the new roll, so that the adhesive side is directed outwards and is only partly covered by

EP 1 989 136 B1

- 2 new tape. The remaining part of the outside facing adhesive is glued to the tape of the old roll. In this method, to prevent the tape from unwinding when the new roll accelerates to the peripheral speed of the old roll, liquid is introduced between the upper roll of the new roll and the roll below it, so that the upper roll is fixed on the underlying roll by capillary forces. The disadvantage of this method is that also with this method it is necessary to employ highly qualified personnel, and yet technically advantageous results are not always obtained, since the effectiveness of liquid strip determination depends on many parameters, e.g. surface energy, elasticity and surface mass tape, from the amount of liquid used, its polarization, viscosity, density and layer thickness, surface and shear resistance of the liquid layer. An important disadvantage of this method is that the belt speed when changing the rollers cannot be too high and the line and the belt can be contaminated by the liquid used.

[0006] The above method is also used in the paper industry. Another version of the first method is the splicing method used there, in which the retainer is placed in an adhesive tape connecting paper tapes. After joining the tapes, the substrate delaminates, serving as a retaining element, as a result of which part of the delaminated substrate remains on the adhesive tape connecting the tapes (i.e. on the top scroll), while the other part remains on the scroll below. "Fissile" are defined as substrates which delaminate parallel to the direction of the surface elongation, and especially those substrates that, in relation to the requirements of the gluing method, actually delaminate.

[0007] Several products are known in the paper industry to implement this method. For example, DE 196 32 689 A2 discloses an adhesive tape which, in addition to the main substrate, also has a fissile paper substrate. At dynamic loads, when joining both rollers' tapes, the paper substrate breaks down and its remains cover the adhesive mass used for gluing in the area, which in the case of other adhesive tapes remains exposed. DE 199 02 179 A1 also discloses this type of adhesive tape in which the fissile paper substrate is displaced relative to the main substrate to prevent cracks in the event of loading.

[0008] EP A2 1 342 684 describes an adhesive tape for dynamic replacement of tape rolls, with an adhesive top side and a non-adhesive bottom side, and with

EP 1 989 136 B1

- 3 two longitudinal edges, with the main substrate, which is coated on one side with a self-adhesive mass on top, whereby a part of the non-adhesive underside has at least one self-adhesive system and a splitting method for dynamic replacement of rolls containing a wound tape.

[0009] In order to improve the dynamic exchange of rolls in the film and nonwovens processing industry, it would be desirable to use adhesive tapes with a structure similar to those already known from the paper industry. This is particularly desirable for films and nonwovens with non-polarized surfaces. Such polarized surfaces are found for materials with low surface energy, such as polyethylene, polypropylene, polyethylene terephthalate (PET) or polymer coated papers. Surface energy is small when it is 50 mN / m or less. Self-adhesive masses are particularly sticky and very adhesive for this type of non-polarized surface. The high adhesive strength required and high tack (so-called "tack") can usually be obtained in such a way that the fluidity of the adhesive mass increases.

[0010] Traditionally used adhesive masses with high adhesive strength and high tactile tack are not suitable, or only slightly, for dynamic replacement of rolls containing non-polarized films and nonwovens using the splitting method. Increasing the adhesive strength and tactile adhesive mass is associated with an increase in their fluidity. This type of adhesive, due to its high fluidity, is squeezed out of the fissile system, equipped with an adhesive, and can even penetrate into the fissile substrate, which can lead to blocking of the fissile system and to the release of the adhesive connection. Furthermore, it is disadvantageous that liquid adhesive compounds escape from the adhesive joint during splitting, and thus, after splitting, adhesive residue may remain in the system without coating.

[0011] The object of the invention is therefore to provide an adhesive mass, at least equipped with an upper self-adhesive mass, a fissile substrate and a lower self-adhesive mass on the bottom side of the fissile substrate, suitable for dynamic roller replacement with a non-polarized tape wound at high belt speeds.

EP 1 989 136 B1

[0012] This task can be sensationally solved by means of an adhesive tape suitable for dynamic exchange of rolls with a wound tape with non-polarized surfaces, in particular with polyolefinic substrates, in which as a top self-adhesive mass a non-silicone adhesive mass is used, with adhesive strength a polyethylene substrate of 1.5 N / cm or more (measuring method: tesa test) and with tactile stickiness corresponding to a turning length of 200 mm or less (measuring method: test D), in which the bottom self-adhesive mass is self-adhesive mass with an adhesive strength on a polyethylene substrate of 1.5 N / cm or more (measuring method: tesa test) and with a complex viscosity of 10,000 Pa^.s or more at 1 rad / s and 40^aboutC (measuring method: F tes test).

[0013] For dynamic roller exchange, it is particularly advantageous if the tactile tack of the upper adhesive mass corresponds to a turning length of 50 mm or less (measuring method: D tesa test).

[0014] The upper adhesive mass in the splitting method serves to connect the upper surface of the adhesive tape according to the invention to the beginning of the tape of the new roll and the tape of the old roll almost completely unwound, as a result of which the tapes of both rollers are joined together by means of the adhesive tape. The lower self-adhesive mass is used to connect the lower surface of the adhesive tape according to the invention to the second roll from above, so that the upper and second rolls of the new roll are joined together first by means of an adhesive tape. In the further course of the splitting method, when delamination of the fissile substrate, the connection of the two upper turns of the roll is disconnected again and in such a way that the adhesive areas of the upper adhesive mass facing away from the upper surface of the respective roll and the lower adhesive mass of the already split substrate remain covered in a way that lacks adhesive properties.

[0015] It is important for the invention to shape the upper self-adhesive mass and the lower self-adhesive mass in terms of their adhesive strength, tactile stickiness and viscosity. According to the invention, the choice of the complex viscosity of the lower adhesive mass causes the cold flow of the lower adhesive mass to be prevented. As a result, the adhesive at the bottom of the fissile substrate must not flow out of the adhesive connection and stick to the top of the fissile substrate, thereby preventing blockage of the substrate and the system still retaining the splitting ability.

EP 1 989 136 B1

[0016] For the upper self-adhesive mass, it is particularly advantageous to select such a mass that meets the requirements of the film gluing process. It is preferred that it has sufficient tactile stickiness (so that during the splitting process on non-polarized materials, especially on polyolefinic substrates, it can be easily gripped), during the process it should not undergo shearing on such substrates, and therefore has good shear strength and showed a sufficiently high adhesive strength also on the polyolefin material.

[0017] The determination of the adhesive strength was carried out as follows (A tesa test): a polyethylene plate was used as a defined adhesive substrate (plate with a specified adhesive strength), made as an injection control plate, made of Hostalen GC7260 HDPE granules (high pressure polyethylene) Basell. This plate was washed with ethanol before measurement. The sample to be tested was a standard polyester base with a thickness of 23 μm and was coated on one side with a suitable adhesive (adhesive layer: 50 g / m²). A strip of coated standard polyester substrate, 20 mm wide, was pressed against the adhesive substrate (2 kg). Immediately after, the adhesive tape was torn away from the ground at an angle of 180^about, at a speed of 300 mm / min and the measured force needed for this at room temperature. The measured value (in N / cm) was determined as the average of three measurements. For calibration of the "tesa test" measuring method, a commercially available test adhesive tape was used to test non-stick coatings (type "tesa 7475" by tesa AG; the adhesive strength on steel is 31.25 N / 25 mm); the adhesive strength determined on the polyethylene control plate was 4.5 N / cm.

[0018] Partially, comparative tests were carried out on steel instead of polyethylene, with identical other test parameters (test A2).

[0019] Determination of tactile stickiness was carried out as follows (Test tesa): as a measure of tactile stickiness with a very short contact time, the so-called Rolling-ball-Tack. The tests were carried out on a sample being a standard polyester substrate with a thickness of 23 μm, coated on one side with each tested adhesive mass (coating of adhesive mass: 50 g / m²). On the test surface, a strip of adhesive tape about 10 cm long was fixed horizontally with the adhesive side up. Steel ball, intended for testing (diameter: 11 mm;

EP 1 989 136 B1

- 6 mass: 5.6 g), washed with acetone and conditioned for 2 hours in a room microclimate (temperature 23^aboutC ± 1^aboutC; relative humidity 50% ± 1%). To carry out the measurement, the steel ball was accelerated in the gravitational field by rolling it off a 65 mm high incline (angle of inclination 21^about). The steel ball was directed from the inclined plane directly on the adhesive surface of the sample. The distance traveled by the ball on the adhesive mass was measured until the ball stopped. The turning distance determined in this way is an inverse measure of the tactile tack of the adhesive (i.e. the shorter the rolling distance, the greater the tactile tack and vice versa). Based on the results of measurements, the average value of five measurements was determined (as the length of the segment in mm).

The determination of the complex viscosity was carried out as follows (F tes test): the pressure-sensitive adhesive mass obtained in the form of a cylindrical sample 25 mm in diameter and 0.8 mm in height, was tested in a deformation-controlled rheometer (type RDA III, Rheometrics Scientific; plate - plate - measuring head system: 2000 g Bendix) (with 3 N axial preload). The dynamic measurement was carried out at a temperature of 40^aboutC, in the room microclimate (conditions according to the standard) and with 3% deformation of the sample, in the frequency range from 0.1 to 500 rad / s, as the complex viscosity η *. The numerical value (in Pa ^ s) of "complex viscosity" is the value of the complex viscosity measured in the low frequency region (1 rad / s) and at 40^aboutC.

[0021] For the adhesive tape according to the invention, it is advantageous if a mass is used as the upper self-adhesive mass and / or lower self-adhesive mass which on the polyethylene pressure-sensitive substrate has an adhesive strength of 3.0 N / cm or more (measuring method: Test A test ), it being particularly preferred if the adhesive strength on the polyethylene pressure-sensitive substrate is 5.0 N / cm or more. Thanks to this, particularly effective adhesion of the adhesive tape on the non-polarized tape to be joined is achieved, which further improves the durability of the connection and thus the effectiveness of the gluing method.

[0022] It is furthermore advantageous if a mass that exhibits tactile stickiness corresponding to a rolling distance of 40 mm or less is used as the upper adhesive mass (measuring method: D tes test), it is particularly advantageous when the rolling distance is used as a measure of tactile stickiness,

EP 1 989 136 B1

- 7 is 20 mm or less. As a result, a particularly high efficiency coefficient is achieved when connecting the belts by jointly guiding both rotating rollers.

[0023] As the upper self-adhesive mass, in particular, all common non-silicone self-adhesive masses, intended for non-polarized surfaces, are used, with those having high adhesive strength, high tactile stickiness and high cohesion, especially acrylates, natural rubber masses, being preferred. and particularly preferably adhesive compounds based on styrene block copolymers. Self-adhesive masses not suitable for reuse are particularly suitable for this.

[0024] As upper self-adhesive masses, preferably block copolymer based masses, in particular styrene block copolymers, are preferably used. In this case, according to the invention, copolymers formed from blocks of aromatic polymers of vinyl compounds, particularly preferably formed from blocks of styrene (blocks A) and polymer blocks, by polymerization of 1,3 dienes (blocks B), such as butadiene and isoprene or copolymer. The copolymer can be e.g. copolymer from the above-mentioned butadiene and isoprene compounds.

[0025] Blends of various block copolymers as well as partially or fully hydrogenated products can also be used.

[0026] Particularly preferred is the use of block copolymers of one of the components consisting of block copolymers with a linear ABA structure. In addition, the use of linear multi-block copolymers is preferred. The use of block copolymers in radial form and star-shaped block multi-copolymers is particularly preferred.

[0027] As another component, preferably AB block copolymers are used, especially those which are based on the above-mentioned block monomers A and B.

[0028] According to the invention, it is particularly advantageous if a self-adhesive mass based on a mixture of several styrene block copolymers in which at least one of the copolymers is a double-block copolymer and one of the blocks is formed on the basis of a self-adhesive mass (1, 11) styrene.

EP 1 989 136 B1

[0029] According to the invention, it is possible to use, as an upper self-adhesive mass, for example diblock copolymers containing SIS - styrene-isoprene-styrene with the above-mentioned proportions of styrene or diblocks, as for example commercially available under the trade name Europrene^® SOL T-192 from EniChem (styrene content 25% by weight, diblock content 23% by weight).

[0030] Adhesives that have at least a block copolymer blend in which the styrene content is at least 25% by weight and more preferably 30% by weight and in which the content of diblocks is at least 40% by weight have proved to be particularly advantageous for use on the upper pressure-sensitive adhesive. and more preferably a minimum of 60% by weight. In this way, particularly good shear strength values ​​can be achieved.

[0031] According to the invention, the use of diblocks containing multi-arm (SB) n styrene-butadiene copolymers with the abovementioned styrene and diblock contents, e.g. available under the Kraton trade name, is particularly advantageous as an upper adhesive mass.^® D1118 (content of styrene 33 ± 2% by mass, content of diblocks approx. 78% by mass according to specifications).

[0032] It is advantageous if the content of block copolymers or blend of block copolymers used is in the range from 30% to 70% by weight, in particular in the range from 30% to 55% by weight, based on the pressure-sensitive adhesive.

[0033] Adhesion agents are especially adhesive resins that are well suited to the elastomer block of styrene block copolymers. Suitable adhesive resins are, among others especially non-hydrogenated, partially hydrogenated or fully hydrogenated rosin or rosin derivative resins, hydrogenated dicyclopentadiene polymerizates, non-hydrogenated, partially, selectively or fully hydrogenated hydrocarbon resins based on monomer streams

C-5, C-5 / C-9 or C-9 and particularly preferably polyterpene resins based on α-pinene and / or β-pinene and / or δ-limonene. The abovementioned glue resins can be used both in a mixture and alone. In addition, the content in the adhesive mass of at least one adhesive resin which is liquid at room temperature is particularly preferred.

EP 1 989 136 B1

[0034] As other additives, the following additives may preferably be used, alone or in combination:

• primary antioxidants, e.g. phenols with a spatial obstacle, • secondary antioxidants, e.g. phosphites or thioethers, • process stabilizers, such as C radical scavengers, • preparations protecting against the sun, such as radiation absorbers UV or amines with spatial obstacles, • auxiliary agents, • resins reinforcing the end block.

[0035] It is further preferred that the adhesive resins used contain a lot of liquid resins; especially in an amount of at least 25% by weight, and more preferably at least 35% by weight based on the total weight of the resin used.

[0036] Such a composition exhibits particularly favorable adhesive strength and tactile tack. It is particularly preferred if the upper pressure adhesive has a complex viscosity of 15000 Pa · s or more.

[0037] Usually, an upper adhesive mass coating in the range from 30 to 100 g / m2 is chosen², especially in the range from 35 to 70 g / m2².

[0038] As fissile substrates are all fissile, flat backing materials, especially readily delaminated papers, multilayer papers (e.g. duplex papers and glued papers), multilayer films (e.g. glued films), polymer multilayer systems (e.g. coextruded co-extruded) , multi-layer polymer systems) and polymeric nonwovens. Usually, a substrate with a split strength of 5 to 70 cN / cm, in particular 12 to 60 cN / cm is used.

[0039] It is necessary for the upper and lower adhesive mass to exhibit high adhesive strength.

[0040] The adhesive strength of these self-adhesive masses on suitable surfaces (substrate and tape to be glued) is greater than the force necessary for splitting the delaminated substrate. As the bottom self-adhesive mass

EP 1 989 136 B1

In particular acrylate mass modified with resins is used. Such modified or mixed masses include adhesive resins and acrylate (partially crosslinked) adhesive. As adhesive resins, conventional adhesive resins are used, for example phenol-terpene resins and rosin resins. Acrylate adhesive copolymers with an appropriate glass transition temperature are used, in particular copolymers based on copolymer softening components (e.g. low molecular type C4 to C12 acrylates, such as 2-ethylhexyl acrylate or n-butyl acrylate) and also containing ingredients that cause increasing the hardness of the polymer (for example acrylic acid or functionalized components such as glycidyl methacrylate or ethylene hydroxymethacrylate). Mixing the two masses is used to modify the acrylate adhesive mass with adhesive resin. Crosslinking is then carried out by the usual crosslinking method, e.g. as a crosslinking reaction at high temperatures or by using a suitable catalyst, e.g. Lewis acids e.g. zinc chloride.

[0041] It is furthermore advantageous if a compound having a complex viscosity of 12,000 Pa · s or more (measuring method: Fes test) and especially 15,000 Pa · s or more is used as the lower adhesive mass. Such a configuration helps particularly effectively to prevent blockage of the fissile system and thus to unsealing of the adhesive connection.

[0042] It is also preferred if a resin modified acrylate adhesive is used as the bottom adhesive mass, with 70 to 80% of the mass being acrylate adhesive and 20 to 30% of the adhesive mass being particularly preferred. It is particularly preferred to use as a glue resin - phenol-terpene resin and / or as an acrylate adhesive - a copolymer consisting of n-butacrylate (48.5% by weight), 2-ethylhexyl acrylate (48.5% by weight), glycidyl methacrylate ( 2% by weight) and acrylic acid (1% by weight). These types of compositions exhibit high adhesive strength on non-polar surfaces and nonwovens, and at the same time provide the ability to delaminate a fissile substrate, provided that due to their low fluidity they cannot penetrate either into the fissile substrate or flow out of the adhesive connection. In principle, the upper self-adhesive mass and the lower self-adhesive mass can also be identical to the upper resin modified acrylate mass. In this extremely favorable case, the risk of blocking the fissile system is particularly low. The upper and lower self-adhesive masses can, for example, also be identical as free

EP 1 989 136 B1

- 11 silicones, self-adhesive masses, especially as described above, e.g. based on block copolymers.

[0043] The adhesive tape structures of the invention can be made in various versions. In particular, reference is made to the following documents, the disclosure of which has been fully taken into account in the scope of disclosure in this document:

- DE 196 32 689 A2 (Beiersdorf), in particular the arrangement according to Fig. 1 and the actual situation explained in column 3, lines 31 to 44, the adhesive mass placed on top there (3; between substrate 2 and cover 4) replaced is by the local upper adhesive (1, 11) and / or the local adhesive (also marked with 3) is replaced by the local lower adhesive (3, 13),

- DE 199 02 179 A1 (Beiersdorf), in particular the system according to Fig. 1 and the actual situation explained in column 3, lines 31 to 34, where the N1 adhesive is replaced by the local upper adhesive (1, 11) and / or the adhesive N3 is replaced by the local adhesive (3, 13), while the adhesive N2 can also be replaced by one of the adhesive here (1, 11, 3, 13),

- WO 91/08159 A1 (Norrman), especially the arrangement according to figure 1 and the actual situation explained on page 2, line 35 to page 4, line 14, where the adhesive 3 is replaced by the local upper adhesive (1 , 11) and / or local adhesive 4 is replaced by local adhesive (3, 13),

- DE 198 41 609A1 (Prinz), especially the systems according to Fig. 1 and the actual conditions explained in column 3, lines 7 to 37, the adhesive mass 34 being replaced by the local upper adhesive mass (1, 11) and / or the adhesive 32 there is replaced by the local lower adhesive (3, 13),

- US 2004 / 0075014A1 (Jacobs et al.) Especially the structures according to fig. 1 and the facts discussed in chapters [0049] to [0054], where the adhesive 3 is replaced by the local upper adhesive (1, 11) and / or the adhesive 2 there is replaced by the local lower adhesive (3,

13),

- US 2005 / 0126688A1 (Bean et al.), And in particular the systems according to Figs. 2a, 2b, 2c and 2d and the actual states discussed in chapters [0024] to [0037], with the adhesive masses 20 to 20a being replaced by the local upper adhesive (1, 11) and / or the local adhesive 30a and 30b or 30c is replaced by the local lower adhesive (3, 13),

EP 1 989 136 B1

- 12 - US 6,432,241B1 (Congard et al.), And in particular the systems according to Figs. 1 and 2 and the facts explained in column 3, lines 52 to 64 and in column 4, lines 34 to column 6, line 53, with the adhesive masses 12 are replaced by the local top adhesive (1, 11) and / or the adhesive 15 is replaced by the local bottom adhesive (3, 13),

- US 2002 / 0056784A1 (Davies et al.), In particular the system according to Fig. 2 and the actual state explained in chapters [0038] to [0052], the adhesive masses 16 being replaced by the local upper adhesive (1, 11) and / or the adhesive 24 therein is replaced by the local lower adhesive (3, 13), whereby reference to the above-mentioned forms of implementation does not unnecessarily limit the invention.

[0044] It is particularly advantageous if the adhesive tape comprises an non-fissile substrate, the upper side of which is coated with an upper adhesive mass, and the lower side is connected completely or at least partially to the upper surface of the fissile substrate. By using a non-fissile substrate that connects the old roll tape to the beginning of a new roll tape before and also after delamination of the fissile substrate, a particularly load-bearing connection of both tapes is achieved and the effectiveness of the gluing method is still increased. It is particularly advantageous here when the lower side of the non-fissile substrate is connected (completely or partially) to the upper side of the fissile substrate via a bonding adhesive (five-layer system). This connection can be essentially shaped at will, e.g. using self-adhesive, setting, melting adhesive etc.

[0045] By using a mechanically stable, non-fissile substrate, the gluing method significantly increases the gluing efficiency of the old roll tape with the beginning of the new roll tape. As the main substrate all typical flat substrates for adhesive tapes can be used, e.g. paper substrate consisting of smooth undercoat paper, coated on one or both sides and foil substrates, e.g. BOPP (biaxially oriented propylene films), polyethylene films, aluminized polyethylene films and aluminum films. It is desirable for this to be a tear-resistant main substrate. Any typical self-adhesive compound can be used as the adhesive bonding compound. It is, however, advantageous if the combination of self-adhesive mass and bottom self-adhesive mass

EP 1 989 136 B1

- 13 are identical, e.g. as resin modified acrylate mass, because in this case the risk of blocking the fissile system is particularly low.

[0046] Accordingly, the adhesive tape has a fissile substrate over the entire length of the gluing, and thus also the entire length of the adhesive tape. The fissile medium may cover the entire width of the non-fissile medium. It is, however, advantageous if the width of the fissile substrate is less than the total width of the adhesive tape, so that only a small part of its width is established with the underlying tape. It is particularly advantageous here when the fissile substrate does not end flush with the non-fissile substrate but is retracted relative to it and attached to its underside. As a result, the risk of tearing with the splitting method is further reduced.

[0047] The invention further includes the use of an adhesive tape according to the invention for gluing a tape wound on rolls with an unpolarized surface during dynamic replacement of rolls, especially films and / or nonwovens. The use of adhesive tape significantly increases the efficiency of the method of gluing.

Finally, the invention offers a method of gluing with dynamic exchange of rolls with a wound, non-polarized tape, in particular of foil and / or nonwovens, wherein at the end of the upper tape of a new roller containing non-polarized tape the adhesive tape according to the invention is glued (at least in part), and the bottom surface of the adhesive tape is glued to the underlying tape of the new roll and secured by it, after which the new roll fitted in this way is placed next to almost completely unwound, the roller to be replaced and accelerates to the same peripheral speed, then the new roller is pressed against the upper tape of the old roller, whereby the uncovered adhesive mass of the adhesive tape is glued to the old tape, at almost equal speed of the tapes, while at the same time the system splits the fissile and adhesive masses of the fissile system are covered by both stratified remains of the fissile substrate, in a manner devoid of adhesive properties.

The invention is described in more detail on the basis of examples, with reference to a drawing, the individual figures of which show:

EP 1 989 136 B1

Fig. 1 - schematic side view of an adhesive tape system according to the invention (three-layer system, shown transversely to the longitudinal direction of the adhesive tape) and

- Fig. 2 - schematic side view of another embodiment of an adhesive tape according to the invention (five-layer system, shown transversely to the longitudinal direction of the adhesive tape).

[0050] In Fig. 1, an adhesive tape according to the invention is shown, suitable for dynamic replacement of rolls containing a wound tape with non-polarized surfaces. The adhesive tape has a three-layer structure, with a fissile substrate 2, the upper surface of which is coated with an upper adhesive mass 1, and the lower surface with a lower adhesive mass 3. Such a system is used when the fissile substrate 2 exhibits sufficient mechanical load capacity along the surface deformation direction to withstand the loads that occur when joining a tape from an almost unrolled roll with the beginning of the tape of a new roll.

[0051] The adhesive tape additionally comprises a distribution system 6 for covering the upper adhesive mass 1 in a manner devoid of adhesive properties so that the adhesive upper surface of the adhesive tape is protected during storage. The distribution system can be all traditionally used separation papers, e.g. siliconized papers or siliconized films. In this case, the distribution system can be one-part or multi-part (not shown in figure 1).

[0052] Fig. 2 shows another, particularly preferred configuration of the adhesive tape according to the invention, having a five-layer structure. Such adhesive tape includes fissile substrate 12 and non-fissile substrate 14 connected to each other. The connection is made here by means of a separate, adhesive self-adhesive compound 15, which connects the upper surface of the fissile substrate 12 with the lower part of the non-fissile substrate 14. Thus, the upper surface of the non-fissile substrate 14 is coated with an upper adhesive mass 11 and on a part of its lower surface is coated by an adhesive mass 15 which attaches the fissile substrate 12 to the non-fissile substrate 14. The fissile substrate 12 is retracted in relation to the non-fissile substrate 14 or positioned offset.

EP 1 989 136 B1

[0053] The system shown in Fig. 2 additionally has a distribution system 16 to cover the upper self-adhesive mass 11 in a way that does not render sticky. All traditionally used release papers, e.g. siliconized papers or siliconized films, are used for this purpose. Particularly preferred is the two-part distribution system 16a / 16b shown here, which in the longitudinal direction is divided into a rear casing 16a and a front casing 16b, optionally by means of perforation or a groove. This has the advantage that the adhesive tape can be initially glued to the beginning of the tape of the new roll, whereby the adhesive area of ​​the adhesive tape is exposed only underneath the rear cover part 16a, and the adhesive area used to stick to the tape of the old roll still remains covered by the front part shield 16b and thus remains protected.

[0054] In order to explain the second configuration of the adhesive tape according to the invention, a specific embodiment is presented below:

Example 1:

[0055] The adhesive tape according to the invention, 50 mm wide, was made of a machine-coated backing paper with an area weight of 54 g / cm² and 66 μm thick as non-fissile substrate 14. The upper surface of the non-fissile substrate 14 is coated with an upper adhesive mass 11.

[0056] As the upper self-adhesive mass 11, a synthetic rubber based on styrene block copolymers was used, with the following composition: 48% by weight - styrene-butadiene-styrene block copolymer (type Kraton D1118 from Kraton), 24% by weight α-pinene resin (type "Dercolyte A115" from DRT, softening point 115^aboutC), 27% by mass - liquid hydrocarbon resin (type "Wingtack 10" from Goodyear - liquid, synthetic, aliphatic C-5 polyterpene / hydrocarbon resin; softening point 10^aboutC), 0.5% by weight - primary antioxidant (type "Irganox 1010" by Ciba) and 0.5% by weight - secondary antioxidant (type "Weston 339" by Interorgana).

[0057] The adhesive tape further comprises a fissile substrate 12 and a lower adhesive mass 13 and a bonding adhesive material 15. As a fissile substrate 12 paper with a surface weight of 51 g / cm was used.² and 90 μm thick. The width of the fissile medium 12 was 12 mm.

EP 1 989 136 B1

[0058] Furthermore, the adhesive tape comprises a two-part distribution system 16 for covering the upper adhesive mass 11, in a way that deprives it of adhesive properties, so that the adhesive upper surface is protected during storage of the adhesive tape according to the invention. The illustrated distribution system 16 is made of siliconised distribution paper and includes a rear casing 16a covering the part of the adhesive tape connected to the top layer of the new roll tape and a front casing 16b covering the part of the adhesive tape which is connected to the old roll tape. Both casing parts are separated by a cut, running parallel to the longitudinal direction of the adhesive tape.

[0059] As the bottom adhesive mass 13 and bonding adhesive mass 15, identical adhesive masses having the following composition were used: 75% by weight of an acrylate-based polymer (as acrylate adhesive) and 25% by weight of phenol-terpene resin (as resins).

[0060] The product "DT110" from DRT was used as the phenol-terpene resin. As a polyacrylate-based polymer, a copolymer consisting of butyl n-acrylate (48.5% by weight, 2-ethylhexyl acrylate (48.5% by weight), glycidyl methacrylate (2% by weight) and acrylic acid (1% by weight) was used. This polymer has a mass average molecular weight of 950,000 m / mol and a polydispersity with a value of D = 8.7 (determined on the basis of the results of gel chromatography, performed on 100 μl of a filtered sample containing 150 μg of a soluble copolymer in tetrahydrofuran), using tetrahydrofuran as eluent (0.5 ml / min), pre-column (type PSS SDV 10 μm, internal diameter 8 * 50 mm) and distribution column (type PSS SDV 10 μm, linear one, internal diameter 8 * 300 mm) by Polymer Standards Service and differential refractometer (Shodex RI71) for detection; calibration was carried out using a narrowly distributed polystyrene standard (PSS Ready Cals; Polymer Standards Service); conversion of polystyrene calibration to calibration based on polymethyl methacrylate was carried out using the Mark-Houwink coefficient for polystyrene (K = 0.0136; a = 0.7140) and polymethyl methacrylate (K = 0.0126; a = 0.6880). For crosslinking, zinc chloride (0.3% by weight) was added to the blend as Lewis acid based on the dry weight of the copolymer and drying was carried out for 15 min at 120^aboutC.

EP 1 989 136 B1

[0061] First, the adhesive properties of the upper adhesive mass 11 and the lower adhesive mass 13 or the adhesive mass 15 were tested by determining the adhesive strength of the adhesive masses on an adhesive polyethylene substrate (measuring method: A tesa test), their tactile stickiness based on Rolling -Ball-Tacks (measuring method: D tesa test) and the viscosity of the adhesive mass (measuring method: F tesa test).

[0062] Next, the adhesive properties of adhesive tape manufactured using self-adhesive masses 11, 13 and 15 were tested. To this end, the shear strength of the adhesive tape on a polyethylene substrate was determined as shear resistance (tesa B test). For this purpose, a strip of adhesive tape, 13 mm wide and 20 mm long, was placed on a control plate previously cleaned with ethanol and pressed four times to the substrate using constant pressure. The adhesive tape was loaded at room temperature with a mass of 1 kg and shear resistance (in minutes) was determined as the average of 3 measurements.

[0063] In addition, the relative stratification characteristics of the fissile substrate, coated on both sides with adhesive masses, were tested (C tesa test). As a comparative value, the stratification characteristics of the fissile substrate that was not coated with adhesive materials were used for this. For measurement, 12 cm long coated and uncoated substrate strips were first stored for 24 hours at 40^aboutC, under load (2 kg / cm²). To carry out the measurement, the substrates were stratified over a 2 cm section and the force needed for further splitting of the substrates at a speed of 300 mm / min was measured. It was assumed that the test was met when the difference in forces needed to further split coated and uncoated substrates was less than 20%.

EP 1 989 136 B1

[0064] The test results are presented for the upper adhesive mass 11 and for the lower adhesive mass 13 / bonding adhesive mass 15 in table 1, with reference to the type of test used each time (tesa test).

Table 1:

<td>Mass Self-adhesive (reference)</td><td>Adhesive strength [N / cm] (test A)</td><td>Resistance to shear [Min] (test B)</td><td>relative characteristics and delamination (test C)</td><td>Section rolling [Mm] (test D)</td><td>Viscosity complex [Pa^.s] (test F)</td>

<td>upper (11)</td><td> 8,2</td><td> &gt; 10.000</td><td> -</td><td> 4</td><td> 25.000</td>

<td>lower (13) connecting (15)</td><td> 2,0</td><td> &gt; 10.000</td><td>fulfilled</td><td> 40</td><td> 16.000</td>

[0065] Similarly to example 1, several other adhesive tapes according to the invention were made and measured, in which the upper mass has the following composition (total adhesive composition: 99% of the base adhesive, 0.5% of the original antioxidant (company type "Irganox 1010" Ciba) and 0.5% secondary antioxidant (type "Weston 339" from Interorgana), according to example 1). Compare with table 2.

EP 1 989 136 B1

- 19 Table 2:

<td rowspan="2">Example</td><td rowspan="2">Base composition of the upper mass self-adhesive (11)</td><td colspan="2">Adhesive strength [N / cm]</td><td rowspan="2">Resistance to shear [min] (test B)</td><td rowspan="2">Rolling stretch [Mm] (average value from 3 measurements) (test D)</td>

<td>steel (test A2)</td><td>polyethylene (test A)</td>

<td> 2</td><td>45% Kraton D1118, 25% Dercolyte A115, 30% Wingtack 10</td><td> 11,6</td><td> 10,8</td><td> 8023</td><td> 3</td>

<td> 3</td><td>45% Kraton D1118, 30% Dercolyte A115, 25% Wingtack 10</td><td> 14,0</td><td> 12,4</td><td> 2750</td><td> 27</td>

<td> 4</td><td>50% Kraton D1118, 30% Dercolyte A115, 20% Wingtack 10</td><td> 14,0</td><td> 11,0</td><td> 14963</td><td> 8</td>

<td> 5</td><td>50% Kraton D1118, 25% Dercolyte A115, 25% Wingtack 10</td><td> 8,8</td><td> 8,8</td><td> 6337</td><td> 2</td>

<td> 6</td><td>45% Europrene SOL T-192, 25% Dercolyte A115, 30% Wingtack 10</td><td> 11,8</td><td> 8,0</td><td> 4809</td><td> 12</td>

<td> 7</td><td>45% Europrene SOL T-192, 25% Dercolyte A115, 30% Wingtack 10</td><td> 11,8</td><td> 8,0</td><td> 4809</td><td> 12</td>

<td colspan="6">All trade names: ®</td>

[0066] The practical test of the use of adhesive tapes produced in this way for the dynamic replacement of polyethylene film rolls with a thickness of 35 μm to 60 μm has been successful.

EP 1 989 136 B1