Detachable self-adhesive article having at least one layer of a pressure-sensitive adhesive

Abstract

The present invention relates to a self-adhesive article having at least one layer H1 of a pressure-sensitive adhesive. The pressure-sensitive adhesive contains the following constituents: (a) an elastomer component, and (b) an adhesive resin component, and (c) a reinforcing component, wherein the elastomer component (a) has at least one type of a polyvinyl aromatic polybutadiene block copolymer P having a linear ABA structure or a linear (AB)2Z structure or radial (AB)n structure or radial (AB)n-Z structure, where in each case n ≥ 3 and having at least one type of a diblock copolymer D having an AB structure or (AB)Z structure, wherein A stands for polyvinyl aromatic, B for polybutadiene and Z for the derivative of a coupling substance, and wherein the polyvinyl aromatic content of the polyvinyl aromatic polybutadiene block copolymer P is from 20 to 40 wt.%, and wherein the adhesive resin component (b) is at least one adhesive resin having an MMAP of 55 to 85°C, a DACP of 5 to 50°C and a softening temperature of at most 130°C, preferably at most 120°C and at least 80°C, and wherein the reinforcing component (c) is at least one resin having an MMAP of -10°C to 30°C, preferably 0°C to 20°C, and a softening temperature of at least 140°C.

Description

[0001] tesa SE Norderstedt

[0002] Description

[0003] Removable self-adhesive article comprising at least one layer of an adhesive compound

[0004] The present invention relates to a self-adhesive article comprising at least one layer of an adhesive compound.

[0005] Self-adhesive articles that can be removed from an adhesive joint without residue or damage by stretching are known (see, for example, the publications cited in EP 3 362 528 B1). Likewise, self-adhesive articles suitable for attaching loads to walls are known. The particular mechanical stress, namely the so-called tilting-shear stress, on the self-adhesive article proves to be extremely challenging. In addition to the specific deformation of the self-adhesive article under tilting-shear stress, the interaction between the surface of the self-adhesive article and the wall surface and its properties also plays a role. These self-adhesive articles are typically required to be universally applicable to various types of substrates with regard to surface chemistry and topography. When it comes to bonding to walls, there is a trend towards new types of paint.Depending on the formulation of modern paints, the adhesive properties of the pressure-sensitive adhesives used in these self-adhesive products face specific challenges. Furthermore, the topographical surface characteristics of wall substrates pose a particular challenge to the performance of the self-adhesive product. Sufficient tear resistance is also essential for removability by stretching.

[0006] US Patent 6,231,962 B1 describes self-adhesive articles that can be detached from a substrate by stretching and contain a foam carrier. Among other formulations, a formulation based on a radial polystyrene-polybutadiene (SBS) block copolymer in combination with a polystyrene-polybutadiene diblock copolymer, a polyterpene adhesive resin with a softening temperature of 135 °C, and a mineral oil as a plasticizer is proposed.

[0007] EP 3 362 528 B1 discloses self-adhesive articles that can also be detached from a substrate by stretching and contain a foam carrier. The proposed pressure-sensitive adhesive formulations are based on a linear SBS triblock copolymer in combination with a polystyrene-polybutadiene diblock copolymer, a polyterpene adhesive resin, and a soft resin as a plasticizer.

[0008] WO 2008 / 073 669 A1 discloses formulations comprising a linear and a multi-armed block copolymer, a polydiene-compatible adhesive resin, a polyvinyl aromatic-compatible adhesive resin, and a plasticizer. The formulation can be a layer of a self-adhesive article containing a foam carrier. Formulations based on polystyrene-polyisoprene block copolymers are explicitly mentioned. The polystyrene content of the explicitly mentioned block copolymers is significantly below 20% by weight in each case. Self-adhesive articles that can be removed from a substrate by stretching are not mentioned. For the explicitly mentioned formulations, no self-adhesive product suitable for removal by stretching was considered in combination with a foam carrier.For the explicitly mentioned block copolymers, sufficient tear resistance for a detachment process through stretching cannot actually be expected.

[0009] WO 2015 / 195 602 A1 addresses the challenge of proposing self-adhesive articles that can be detached from a substrate by stretching and achieve improved adhesion to specific wall paints. The proposed pressure-sensitive adhesive formulations contain at least one hydrocarbon-based block copolymer and a polar, oxygen-containing adhesive resin, namely a terpene phenol resin. The use of the polar adhesive resin is intended to improve adhesion to the wall paints. The influence of the formulation on tear resistance is not disclosed.The present invention is based on the objective of providing a self-adhesive article comprising at least one layer of an adhesive compound, which can be detached from a substrate with improved tear resistance and at the same time offers very good holding performance even on modern wall paints and which, due to its adaptability, can also be used on wall surfaces with different surface topographies.

[0010] This problem is solved in an unexpected way by the self-adhesive article according to claim 1. The dependent claims relate to advantageous further developments of the invention. Further advantageous embodiments of the invention will become apparent from the description below.

[0011] Such embodiments, and others referred to below as preferred, are combined in particularly preferred embodiments with features of other embodiments referred to as preferred. Combinations of two or more of the embodiments referred to below as particularly preferred are therefore especially preferred. Also preferred are embodiments in which a feature of one embodiment referred to as preferred to any degree is combined with one or more further features of other embodiments referred to as preferred to any degree.

[0012] The present invention relates to a self-adhesive article comprising at least one layer H1 of an adhesive compound, wherein the adhesive compound contains the following components:

[0013] (a) an elastomer component, and

[0014] (b) an adhesive resin component, and

[0015] (c) a reinforcing component, wherein the elastomer component (a) is at least one type of polyvinyl aromatic polybutadiene block copolymer P having a linear ABA structure or a linear (AB)2Z structure or radial (AB) n - Structural or radial (AB) n-Z structure with n > 3 and at least one type of diblock copolymer D with an AB structure or (AB)Z structure, wherein A represents polyvinyl aromatic compound, B represents polybutadiene and Z represents the derivative of a coupling substance, and wherein the polyvinyl aromatic compound content of the polyvinyl aromatic-polybutadiene block copolymer P is 20 to 40 wt.%, and wherein the adhesive resin component (b) is at least one adhesive resin having an MMAP of 55 to 85 °C, a DACP of 5 to 50 °C and a softening temperature of at most 130 °C, preferably at most 120 °C, and wherein the reinforcing component (c) is at least one resin having an MMAP of -10 °C to 30 °C, preferably 0 °C to 20 °C, and a softening temperature of at least 140 °C.

[0016] Pressure-sensitive adhesives based on polyvinyl aromatic-polydiene block copolymers are characterized by their typically two-phase structure, meaning they consist of two types of spatially separated, identifiable regions. One type is enriched with polyvinyl aromatic blocks, and the other with polydiene blocks. Through targeted formulation with adhesive resins and, if necessary, other mixture components, the regions enriched with polyvinyl aromatic blocks contribute to the cohesion of the pressure-sensitive adhesive, while the regions enriched with polydiene blocks contribute to its adhesive properties. The latter typically constitute the majority of the pressure-sensitive adhesive layer by volume. Adhesive failure is a common failure mode observed in tests of holding performance under tilting shear stress.It is therefore logical to improve the holding performance under tilting shear stress by enhancing the adhesive properties of the pressure-sensitive adhesive and, for this purpose, by influencing the composition of the areas enriched with polydiene blocks. WO 2015 / 195 602 A1 accordingly proposes the use of polar adhesive resins.

[0017] However, it was unexpectedly found that pressure-sensitive adhesives are also well suited for new paints where the formulation influences the composition of the areas enriched with polyvinyl aromatic compounds. This is all the more surprising since the advantageous effect is achieved through the use of non-polar additives. Surprisingly, the self-adhesive products according to the invention, containing a reinforcing component and an adhesive resin with a DACP of 5 to 50 °C and an MMAP of 55 to 85 °C, in combination with the other components, show an improvement in tear resistance compared to a reference system without this reinforcing component or containing an adhesive resin with an MMAP of less than 55 °C.At the same time, the examples according to the invention demonstrate very good adhesion performance even on modern wall paints, as can be seen from the tilt-shear test on the wall paint Caparol Supertäck 5, light matt, RAL 1001. In addition, the examples according to the invention show high shear strengths, as can be seen from the shear life and the failure temperature SAFT.

[0018] The self-adhesive article according to the invention preferably fulfills the performance requirement specified in Table 1.

[0019] Table 1 - Preferred performance profile

[0020] Adhesive layer

[0021] The adhesive compound of at least one layer H1 of an adhesive compound of the self-adhesive article according to the invention is described in more detail below.

[0022] In accordance with common understanding, an adhesive is defined as one that allows a permanent bond to almost all substrates even under relatively light pressure and can be removed from the substrate after use with virtually no residue. An adhesive is permanently tacky at room temperature, meaning it has a sufficiently low viscosity and high initial tack to wet the surface of the substrate even with minimal pressure. The adhesive's bonding ability is based on its adhesive properties, while its removability is based on its cohesive properties.

[0023] (a) elastomer component

[0024] The pressure-sensitive adhesive contains (a) an elastomer component, wherein the elastomer component (a) is at least one type of polyvinyl aromatic polybutadiene block copolymer P having a linear ABA structure or a linear (AB)2Z structure or radial (AB) n -Structure or radial (AB) n -Z structure with n > 3 in each case and at least one type of diblock copolymer D with an AB structure or (AB)Z structure, wherein A represents polyvinyl aromatic, B represents polybutadiene and Z represents the derivative of a coupling substance, and wherein the polyvinyl aromatic content of the polyvinyl aromatic-polybutadiene block copolymer P is 20 to 40 wt.%.

[0025] Examples of coupling substances that can be used according to the invention can be found, among others, in Holden (G. Holden, DR Hansen in “Thermoplastic Elastomers”, G. Holden, HR Kricheldorf, RP Quirk (eds.), 3rd ed. 2004, C. Hanser, Munich, pp. 49f), without intending to limit ourselves here.

[0026] The values ​​for A, B and Z refer to the polyvinylaromatic-polybutadiene block copolymers P with a linear ABA structure or linear (AB)2Z structure or radial (AB) n -Structure or radial (AB) n -Z structure and the diblock copolymers D with an AB structure or (AB)Z structure. A, B and Z can be the same or different independently of each other in different polymers.

[0027] The index “n” in each of the given formulas is greater than or equal to three, where three or four is preferred and three is particularly preferred.

[0028] The polyvinyl aromatic-polybutadiene block copolymers preferably comprise one or more rubber-like blocks B (elastomer blocks, soft blocks) and at least two glass-like blocks A (hard blocks). Vinyl aromatics for the construction of the respective blocks A preferably comprise styrene and styrene derivatives, particularly preferably styrene and α-methylstyrene. The respective block A can be in the form of a homopolymer or a copolymer.

[0029] Particularly preferred are the polyvinyl aromatic blocks A of the diblock copolymers D and polyvinyl aromatic-polybutadiene block copolymers P, each polystyrene blocks.

[0030] Therefore, polystyrene (A) is particularly preferred in all of the above-mentioned polymers.

[0031] Instead of the preferred polystyrene blocks, polymer blocks based on other aromatic-containing homo- and copolymers, preferably Cs- to Ci2-aromatics, especially those with glass transition temperatures above 75 °C, can also be used as vinyl aromatics; for example, α-methylstyrene-containing aromatic blocks. The glass transition temperature can be determined, for example, by DSC. The determination by DSC is carried out according to the method described in the methods section of this description.

[0032] The A-blocks of the polyvinylaromatic-polybutadiene block copolymers preferably have a glass transition temperature of at least 25 °C, in particular at least 50 °C.

[0033] For the B blocks, a glass transition temperature of at most -25 °C, in particular at most -50 °C, is preferred.

[0034] These values ​​refer to the pure, unmixed block copolymers and are determined according to the invention using DSC.

[0035] The proportion of A-blocks in the polyvinylaromate-polybutadiene block copolymers P is 20 to 40 wt.%, preferably 25 to 35 wt.%.

[0036] Preferably the proportion of A-blocks in the polyvinylaromate-polybutadiene block copolymers D is 20 to 40 wt.%, particularly preferably 25 to 35 wt.%.

[0037] The block copolymers resulting from the A and B blocks can contain identical or different B blocks, also with regard to their microstructure. "Microstructure" refers to the relative ratio of the possible monomer linkage types for polybutadiene: 1,4-c / s, 1,4-trans, and 1,2.

[0038] It can be done by comparing the integrals of the signals to be assigned to the corresponding groups via 1The ¹H NMR composition is determined. Preferably, the 1,4-part (cis + trans) content is > 80 wt.%, more preferably > 85 wt.%, in each case based on the polybutadiene blocks, and the 1,4-c / s content is > 40 wt.%, based on the polybutadiene blocks; correspondingly, the total proportion of 1,2-linked monomers, i.e., the so-called vinyl content, is preferably less than 20 wt.%, more preferably a maximum of 17 wt.%, and in particular a maximum of 13 wt.%. A high proportion of 1,4-linkage and, in particular, 1,4-c / s linkage of the monomer units in the polybutadiene blocks, or a low proportion of vinyl groups, leads to a lower glass transition temperature, so that good shock resistance can be achieved even in cold environments. According to the invention, butadiene is therefore provided as the monomer for the B-block(s).

[0039] The elastomer component contains one or more grades of copolymer P with the linear ABA structure and / or one or more grades with the linear (AB)2Z structure and / or one or more grades with the radial (AB) n -Structure and / or one or more varieties with the radial (AB) n -Z-structure.

[0040] In particular, a mixture of linear and radial copolymers is conceivable.

[0041] According to advantageous embodiments, the elastomer component (a) contains at least one type of polyvinyl aromatic polybutadiene block copolymer P with a linear ABA or (AB)2Z structure, preferably comprising a total of 65 to 85 wt.% of polyvinyl aromatic polybutadiene block copolymers P with a linear ABA or (AB)2Z structure. The values ​​given in wt.% are based on the total weight of the elastomer component (a).

[0042] In addition to the advantages achieved according to the invention, this also makes the adhesive compound particularly easy to process.

[0043] The elastomer component also contains one or more varieties of the diblock copolymer D with the AB structure and / or one or more varieties with the (AB)Z structure.

[0044] A mixture is also conceivable here.

[0045] Preferably, the elastomer component (a) contains a total of 15 to 35 wt.% of the at least one type of diblock copolymer D and a total of 65 to 85 wt.% of the at least one type of polyvinyl aromatic polybutadiene block copolymer P, wherein the sum of the amounts of diblock copolymer D and polyvinyl aromatic polybutadiene block copolymer P in the elastomer component (a) is 90 to 100 wt.%, preferably 95 to 100 wt.%, and particularly preferably 100 wt.%. The values ​​given in wt.% are based on the total weight of the elastomer component (a).

[0046] Therefore, if the combined amounts of polymers P and D are less than 100 wt.%, the elastomeric component contains further elastomeric components, for example, block copolymers containing polyisoprene blocks. Thus, for example, one or more polystyrene-polyisoprene block copolymers may be present in the elastomeric component. Preferably, however, this is present in a maximum amount of 10 wt.%, and particularly preferably in a maximum amount of 5 wt.%.

[0047] The sum of all elastomeric components of the elastomeric component (a) naturally always results in 100 wt.% based on the total weight of the elastomeric component (a).

[0048] Preferably the diblock content and thus the total amount of diblock copolymers D with an AB structure and / or (AB)Z structure is 18 to 32 wt.%, very preferably 21 to 29 wt.%, based on the total weight of the elastomer component (a).

[0049] According to advantageous embodiments in which no further elastomer is included in the elastomer component (a), the total amount of the more specifically specified copolymers P is then 68 to 82 wt.% or, more advantageously, 71 to 79 wt.%, based on the total weight of the elastomer component (a).

[0050] The pressure-sensitive adhesive preferably contains 20 to 62 wt.% of the elastomer component (a), more preferably 30 to 62 wt.%, particularly preferably 38 to 58 wt.%, and most preferably 42 to 52 wt.%, based on the total weight of the pressure-sensitive adhesive.

[0051] It was found that too low a proportion of polyvinyl aromatic polybutadiene block copolymers results in a decrease in the tear resistance of the self-adhesive article, while too high a proportion of polyvinyl aromatic polybutadiene block copolymers results in the adhesive losing too much adhesive strength, so that the self-adhesive article may no longer be suitable for certain applications.

[0052] (b) Adhesive resin component The pressure-sensitive adhesive compound further comprises an adhesive resin component (b), wherein the adhesive resin component (b) is at least an adhesive resin having an MMAP of 55 to 85 °C, a DACP of 5 to 50 °C and a softening temperature of at most 130 °C, preferably at most 120 °C and at least 80 °C.

[0053] The adhesive resin component is therefore, in particular, one or more specifically specified adhesive resins.

[0054] Within the scope of the present invention, the adhesive resin component is not to be understood as a reinforcing component, i.e., the adhesive resin component is preferably essentially incompatible with the hard blocks of the block copolymers and thus preferably not compatible with the A-blocks made of polyvinyl aromatic compound, in particular polystyrene.

[0055] The adhesive resin(s) are therefore selected so that they are mainly miscible (compatible) with the areas of the pressure-sensitive adhesive compound dominated by the B-blocks made of polybutadiene.

[0056] The adhesive resin component is used in particular to adjust the adhesion as desired. According to the general understanding of those skilled in the art, an "adhesive resin" is understood to be an oligomeric or polymeric resin that increases the adhesion, i.e., the inherent stickiness of the pressure-sensitive adhesive, compared to an otherwise identical pressure-sensitive adhesive without an adhesive resin. Adhesive resins are special compounds with a low molar mass compared to elastomers, typically with a weight-average molecular weight M. w of less than 5,000 g / mol. Typically, the weight-average molecular weight of an adhesive resin component used within the scope of the present invention is from 400 to 5,000 g / mol, preferably from 500 to 2,000 g / mol, as determined by GPC.

[0057] The at least one adhesive resin is characterized, among other things, by having a softening temperature according to the ring-and-ball method of at most 130 °C, preferably at most 120 °C.

[0058] The softening temperature is determined using the ring and ball method according to ASTM E28, as specified in the methods section of this description.

[0059] According to the invention, all adhesive resins in the adhesive resin component (b) have a softening temperature in this range. Thus, the adhesive resin(s) contained as adhesive resin component (b) have a softening temperature that is lower than that of the reinforcing component (c).

[0060] Preferably the softening temperature is at least 80 °C, particularly preferably at least 100 °C, most preferably at least 110 °C.

[0061] At least one adhesive resin is characterized, among other things, by having an MMAP of 55 to 85 °C.

[0062] The MMAP (mixed methylcyclohexane aniline point) is the mixed methylcyclohexane aniline cloud point and is known to those skilled in the art as a measure of the aromaticity of resins. It is determined using the MMAP method described in the methods section of this description.

[0063] At least one adhesive resin is characterized, among other things, by having a DCAP of 5 to 50 °C.

[0064] The DACP (diacetone alcohol cloud point) is the diacetone cloud point and is known to those skilled in the art as a measure of the polarity of resins. It is determined using the DACP method described in the methods section of this description.

[0065] The features defined according to the invention apply to all adhesive resins contained as adhesive resin component (b), since the adhesive resin component (b) is already defined in such a way that it is the at least one -more precisely specified - adhesive resin.

[0066] It follows that the adhesive compound preferably does not contain an adhesive resin that has a DACP of less than 5 °C and / or an MMAP of less than 55 °C.

[0067] Preferably, at least one adhesive resin of the adhesive resin component (b) is selected from the group consisting of resins based on dicyclopentadiene, hydrocarbon resins based on Cs, C5 / C9, Cg monomer streams, polyterpene resins based on α-pinene and / or β-pinene and / or β-limonene and polymers of pure Cs and polymers of pure Cg aromatics, wherein the resin, in particular in the case of polymers of Cs and / or Cg aromatics, is partially or in particular completely hydrogenated.

[0068] In the context of the present invention, "partially hydrogenated" means a degree of hydrogenation of at least 80%, preferably at least 85%. According to advantageous embodiments, the at least one adhesive resin is a polyterpene resin based on α-pinene.

[0069] In particular, at least one of the adhesive resin components is not a terpene phenol resin.

[0070] The pressure-sensitive adhesive preferably contains no adhesive resin that is a terpene-phenol resin. The pressure-sensitive adhesive is therefore specifically free of terpene-phenol resins.

[0071] The proportion of adhesive resin in the pressure-sensitive adhesive compound has a positive effect on bond strength. Therefore, the proportion of adhesive resin should not be too low. However, it has been shown that an excessively high proportion of adhesive resin(s) has a negative impact on thermal shear strength and, in particular, on removability.

[0072] The proportion of the adhesive resin component (b) is preferably 25 wt.% to 55 wt.%, particularly preferably 32 wt.% to 50 wt.%, most preferably 35 wt.% to 45 wt.%, based on the total weight of the adhesive compound.

[0073] (c) Reinforcement component

[0074] The pressure-sensitive adhesive contains a reinforcing component (c), wherein the reinforcing component (c) is at least a resin having an MMAP of -10 °C to 30 °C, preferably 0 °C to 20 °C, and a softening temperature of at least 140 °C.

[0075] Within the scope of the present invention, the reinforcing component is not to be understood as an adhesive resin component, i.e., the reinforcing component is preferably essentially incompatible with the soft blocks, i.e., the polybutadiene blocks.

[0076] According to the invention, so-called end-block amplifiers are used in particular as amplification components.

[0077] End block reinforcers are understood to be materials that are essentially compatible with the hard blocks of block copolymers and thus preferably with the A-blocks made of polyvinyl aromatics, especially polystyrene.

[0078] In the context of the present invention, the terms “essentially incompatible” or “essentially incompatible” are understood to mean, in particular, that the components or constituents in question are miscible with each other to a maximum of 10 wt.%, preferably to a maximum of 5 wt.%.

[0079] In the context of the present invention, the term "essentially compatible" means in particular that the components or constituents in question are miscible with each other to at least 90% by weight, preferably to at least 95% by weight.

[0080] The at least one resin of the reinforcing component (c) is preferably at least one resin based on at least one, in particular aromatic, hydrocarbon compound, which is preferably selected from the group consisting of styrene, alpha-methylstyrene, para-methylstyrene and mixtures thereof.

[0081] The at least one resin of the reinforcing component (c) preferably has a weight-average molecular weight M w from 1,000 g / mol to 15,000 g / mol, preferably 2,000 g / mol to 10,000 g / mol, determined by GPC.

[0082] The at least one resin of the reinforcing component (c) has an MMAP (mixed methylcyclohexane aniline) cloud point of -10 °C to +30 °C, preferably of 0 °C to +20 °C. The MMAP is determined according to the method described in the methods section of this description.

[0083] The softening temperature of the at least one resin of the reinforcing component (c) is at least 140 °C, preferably at least 150 °C, determined according to the ring and ball method described in the method section of this description according to ASTM E28.

[0084] The softening temperature of at least one resin of the reinforcing component is preferably a maximum of 165 °C.

[0085] Preferably, the at least one resin of the reinforcing component (c) has a DACP of at most 0 °C, preferably of at most -15 °C.

[0086] The proportion of the reinforcing component (c) is preferably 2 to 10 wt.%, particularly preferably 2 to 8 wt.%, most preferably 2.5 to 8 wt.%, based on the total weight of the pressure-sensitive adhesive. (d) Plasticizer component

[0087] In addition to the elastomer component (a), the adhesive resin component (b) and the reinforcing component (c), the pressure-sensitive adhesive compound may also contain a plasticizer component (d).

[0088] According to advantageous embodiments of the invention, the adhesive compound also contains a plasticizer component (d).

[0089] Preferably, the plasticizer component (d) is one or more soft resins and / or one or more mineral oils with a softening temperature, determined according to ASTM E28, of less than 30 °C.

[0090] Mineral oils are oils obtained by distilling petroleum, coal, and / or other fossil raw materials and consist primarily of paraffinic (saturated chain-like hydrocarbons), naphthenic (saturated cyclic hydrocarbons), and aromatic (cyclic hydrocarbons with an aromatic double bond system) components. Mineral oils may also contain alkenes (olefins) and, depending on their origin, varying amounts of sulfur-containing and nitrogen-containing organic compounds.

[0091] The aromatic content in the mineral oils used according to the invention should advantageously not be too high (preferably < 5%, more preferably < 2%, and most preferably 0%) so that they are compatible with the soft blocks of the elastomers and essentially incompatible with the vinyl aromatic hard blocks of the elastomers. Highly refined mineral oils such as white oils are very suitable, for example.

[0092] Both technical and medical white oils can be used. Preferred medical white oils are colorless, odorless, and tasteless; they contain no aromatics or sulfur compounds.

[0093] The mineral oil is preferably paraffinic or naphthenic oil, in particular medicinal white oil.

[0094] A soft resin or soft resin mixture is preferred, and a soft resin or soft resin mixture with a melt viscosity at 25 °C and 1 Hz of at least 20 Pa*s, preferably at least 50 Pa*s, is very preferred. The melt viscosity is determined using the method described in the methods section of this description.

[0095] The soft resin is very preferably a hydrocarbon- or polyterpene-based soft resin.

[0096] Soft resins based on rosin are also suitable, especially methyl esters of rosin or of partially or fully hydrogenated rosin.

[0097] Particularly preferably, the plasticizer component (d) is a soft resin, for example and preferably a hydrocarbon resin obtained using Cs monomer streams and optionally in combination with other, in particular Cg monomer streams.

[0098] It has surprisingly been found that the use of the plasticizer component (d), in particular a soft resin, can further improve the removability of the self-adhesive tape. In contrast, the presence of mineral oil or mixtures of mineral oils, which are also commonly used as plasticizers, has proven to be detrimental to removability. Therefore, an embodiment is preferred in which the proportion of mineral oil and / or mixtures of mineral oils in the adhesive compound is at most 3% by weight, and particularly preferably at most 1.5% by weight.

[0099] Despite its negative influence, a higher content of mineral oil and / or mineral oil mixtures may be preferred. For embodiments in which the proportion of mineral oil and / or mineral oil mixtures exceeds 3 wt.% in relation to the total weight of the adhesive compound, a proportion of the reinforcing component (c) of preferably at least 10 wt.% is selected, also in relation to the total weight of the adhesive compound.

[0100] The proportion of plasticizer component (d), based on the total weight of the pressure-sensitive adhesive, is otherwise preferably 2 to 25 wt.%, particularly preferably 2 to 20 wt.%, and most preferably 2 to 10 wt.%. It has surprisingly been found that even a small proportion of plasticizer component in the aforementioned quantities is sufficient to obtain a pressure-sensitive adhesive with a sufficiently high bond strength. (e) further additives

[0101] To further adapt the property profile of the pressure-sensitive adhesive, additional additives, also called aggregates, can be added to the adhesive.

[0102] Preferably, however, their proportion is not more than 18% by weight of the adhesive compound, preferably not more than 10% by weight.

[0103] These additives are primarily protective agents. These include primary and secondary aging inhibitors, light and UV protectants, and flame retardants, but also fillers, dyes, and pigments. The adhesive layer can thus be any color, or white, gray, or black. These and other additives can typically include:

[0104] • Primary antioxidants such as sterically hindered phenols, preferably in a proportion of 0.2 to 1 wt.% based on the total weight of the adhesive compound,

[0105] • Secondary antioxidants, such as phosphites or thioethers, preferably in a proportion of 0.2 to 1 wt.% based on the total weight of the adhesive compound,

[0106] • Process stabilizers such as C radical scavengers, preferably with a proportion of 0.2 to 1 wt.% based on the total weight of the adhesive compound,

[0107] • Light stabilizers such as UV absorbers or sterically hindered amines, preferably in a proportion of 0.2 to 1 wt.% based on the total weight of the adhesive compound,

[0108] • Processing aids, preferably comprising 0.2 to 1% by weight based on the total weight of the adhesive compound.

[0109] Carrier layer T

[0110] According to preferred embodiments, the self-adhesive article according to the invention has at least one carrier layer T.

[0111] Preferably, the support layer T is foamed. Preferably, the foamed support layer T has a density of at most 150 kg / m³. 3 , especially preferred at 30 kg / m 3 up to 150 kg / m² 3 , especially preferred by 45 kg / m 3 up to 120 kg / m² 3 , on.

[0112] This provides self-adhesive articles that are particularly suitable for solving the problem. In particular, the self-adhesive article according to the invention exhibits particularly good conformability to wall surfaces with different surface topographies. Low densities also allow the required conformability. However, excessively low densities pose the risk of the foam carrier tearing under load. Excessively high densities result in insufficient conformability.

[0113] Furthermore, a specific compression stress (50% according to DIN EN ISO 3386-1:2015-10) of at least 50 kPa and at most 300 kPa is preferred for the foamed carrier layer. A compression stress of 70 to 200 kPa is particularly preferred. Systems with insufficient compression stress typically exhibit low tear resistance. Excessively high compression stress results in inadequate conformability, which negatively impacts holding performance.

[0114] For the peeling process, a tensile strength (determined according to DIN EN ISO 527-2:2019-02, test speed 1000 mm / min, as described in more detail in the methods section of the description) in the peeling direction of at least 500 kPa and at most 3500 kPa, preferably at least 1000 kPa and at most 2500 kPa, has proven advantageous. The tensile strength of the foamed carrier layer contributes to the tear resistance of the adhesive strip. If the tensile strength is too low, the adhesive article may tear during peeling by stretching. In this case, a higher tensile strength requirement for the adhesive layers would be necessary, which restricts the formulation options and complicates the achievement of other adhesive properties. If it is too high, the conformability is reduced.

[0115] For the foamed carrier layer, an elongation at break, determined according to DIN EN ISO 527-2:2019-02, test speed 1000 mm / min, as described in more detail in the method section of the description, of at least 200%, preferably at least 250%, is selected in the peel direction. A minimum elongation is required to allow sufficient distance for the adhesive to peel from the substrate. The elongation at break corresponds to the maximum tensile elongation.

[0116] In connection with tensile strength and elongation at break, the release direction of the adhesive product is noted. This is important because the mechanical properties of foam layers used in the substrate material can typically differ in the direction transverse to and longitudinal to their manufacturing direction. For the self-adhesive articles according to the invention, it is initially irrelevant whether the foam layer is used such that the release direction is parallel to the longitudinal direction of the foam layer's manufacturing process or to the transverse direction. What is crucial is that the mechanical properties of the foam layer correspond to the parameter ranges mentioned above, according to the stress occurring during the release process.If, for example, the self-adhesive product is manufactured in such a way that the foam layer is stretched perpendicular to its manufacturing direction during the removal process, then the mechanical properties of the foam layer perpendicular to its manufacturing direction are relevant. Conversely, if the self-adhesive product is manufactured in such a way that the foam layer is stretched lengthwise to its manufacturing direction during the removal process, then the mechanical properties of the foam layer lengthwise are relevant.

[0117] Polyolefin is the preferred material for the foamed carrier layer. Polyethylene-based foams are particularly well-suited. Alternatively, polypropylene-based foam, polyethylene-polyvinyl acetate (EVA) foam, poly(meth)acrylate-based foam, or polyurethane foam can also be used.

[0118] The foam can exhibit any known foam cell structure, i.e., it can be open-cell or closed-cell. The foaming can be achieved through chemical or physical foaming agents, by the introduction of gas or, in particular, air ("frothing"), or by the insertion of hollow spheres. This list is not exhaustive but merely serves as an example. Specific examples include hollow glass spheres, hollow ceramic spheres, hollow metal spheres, and expanded, expandable, and pre-expanded microballoons. Combinations of various foaming methods mentioned above, as well as others, are also possible. The surface(s) of the foamed substrate layer(s) can be chemically and / or physically pretreated to, for example, improve the adhesion of subsequent layers. Examples of pretreatment options include corona treatment, flame treatment, vapor deposition, fluorination, and plasma treatment.

[0119] The foamed support layer T preferably has a thickness of 250 to 1800 pm, particularly preferably 400 to 1500 pm. 500 pm, 800 pm, and 1000 pm are also mentioned as typical support layer thicknesses by way of example.

[0120] This makes the self-adhesive product particularly well-suited for bonding to slightly uneven surfaces, providing high holding power. If the foam is too thin, its conformability to the rough surface is insufficient. The adhesive layer will only make incomplete contact with the surface, resulting in reduced bond strength. If the foam backing is too thick, stress, such as from hanging an object on a hook, will cause excessive deflection of the bond and potentially even tearing of the foam.

[0121] To achieve sufficient tear resistance for the removal process in embodiments with a foamed carrier layer, it has proven advantageous for the self-adhesive article to be designed with a specific balance between minimum tensile strength and elongation at break in terms of its mechanical properties. The following values ​​for minimum tensile strength and elongation at break refer to the self-adhesive article according to the invention and are determined as described in the method section.

[0122] Self-adhesive products with at least one backing material containing a foamed layer and an elongation at break between 600 and 800% are particularly well-suited for the removal process, provided they have a minimum tensile strength of 4 MPa. Alternatively, self-adhesive products with at least one backing material containing a foamed layer and an elongation at break between 450 and 600% are particularly well-suited for the removal process if they have a minimum tensile strength of 5.5 MPa. Another alternative is that self-adhesive products with at least one backing material containing a foamed layer and an elongation at break between 400 and 450% are particularly well-suited for the removal process if they have a minimum tensile strength of 6.5 MPa.

[0123] According to preferred embodiments, the self-adhesive article according to the invention is a double-sided adhesive self-adhesive article, in particular a die-cut or otherwise cut section of adhesive tape or film (adhesive strip).

[0124] According to the present invention, the self-adhesive article according to the invention contains at least one layer of the previously described adhesive compound H1 and preferably at least one layer of a temporary carrier material L1.

[0125] According to preferred embodiments, the self-adhesive article according to the invention is a double-sided self-adhesive article comprising exactly one layer of the adhesive compound H1 described above and one layer of a temporary carrier material L1. In this case, the self-adhesive article preferably has a thickness of 50 to 1500 pm, particularly preferably 100 to 1000 pm. Thicknesses in the range of 250 to 800 pm are also very advantageous.

[0126] According to preferred embodiments, the self-adhesive article according to the invention is a double-sided self-adhesive article with a layer of the described adhesive compound on each side of a permanent foam carrier T, which are each designated as layers H1 and H2 of the described adhesive compound. The two adhesive compound layers H1 and H2 have, independently of each other, the same or different thicknesses within the specified thickness ranges. In this case, the adhesive compound layers preferably have a thickness of 20 to 250 pm, and particularly preferably a thickness of 50 to 150 pm.

[0127] According to preferred embodiments, the adhesive on both sides of the carrier layer is the same adhesive layer, i.e., an adhesive with the same composition and thickness on each side.

[0128] Asymmetrically designed self-adhesive articles containing only one adhesive layer H1 are also according to the invention. The adhesive of a second adhesive layer H2 can meet the aforementioned criteria for the adhesive in adhesive layer H1, but can also be designed differently. Advantageously, however, it is designed such that it can be removed from a substrate by stretching.

[0129] According to preferred embodiments, the self-adhesive article according to the invention is a self-adhesive article that can be removed by stretching.

[0130] Adhesive strips can assume any dimensions in both width and width. They typically have a length of at least 5 mm. Lengths can also be 10 mm, 20 mm, 50 mm, 100 mm, or greater. Widths are typically at least 2 mm. Widths can also be 5 mm, 10 mm, 20 mm, 50 mm, or greater. Although the self-adhesive articles according to the invention can be advantageously used as adhesive strips, they also offer a wide range of applications as assembly tape for product designs according to the invention. In such product designs, the tape width is then, for example, also 5 mm, 10 mm, 20 mm, 50 mm, or greater. However, adhesive tapes are supplied in longer lengths, such as 1.5 m, 5 m, 10 m, or even 50 m. These tapes are then conveniently offered to the user in rolled form.

[0131] The adhesive strips are typically longer than they are wide, with the stretch for easy removal advantageously located along the longitudinal axis. All angles of the die-cut pieces can be 90° or other. Shapes are also possible where the adhesive strip tapers in at least one direction, particularly to a point. Edges can also be rounded.

[0132] Adhesive strips can include non-stick areas on the top and / or bottom of the strip. These areas serve as a pull tab to achieve stretching, particularly in the bonded area, and are therefore preferably non-adhesive on both sides, especially by applying layers of metal, plastic, or paper, as described above. However, the non-stick area can also be created by irradiation, powdering, or neutralization of the adhesive. Alternatively, a lacquer or primer can be applied to the relevant areas. Furthermore, the surface can be modified by chemical treatment such as etching to create non-adhesive zones.A roughness of the handle film with a roughness Sa of 0.10 to 2.00 pm, preferably 0.15 to 0.50 pm, ensures a good adhesive bond between the film and the pressure-sensitive adhesive and can therefore be advantageously selected for this purpose. The roughness is defined according to ISO 25178-2:2012(E) section 4.1.7.

[0133] According to further preferred embodiments, the self-adhesive article according to the invention is a mounting tape with the aforementioned preferred width dimensions. A mounting tape is usually offered in the form of an Archimedean spiral, i.e., in the form of an adhesive tape roll.

[0134] The self-adhesive articles according to the invention are provided, in particular, on a temporary carrier L such as a release liner (preferably siliconized paper or film). The liner can be designed to release on one side. In this case, a second layer of liner is advantageously used to cover the second surface. The liner can also be designed to release on both sides.

[0135] Preferably, the self-adhesive product according to the invention, which can be removed by stretching, can be removed by stretching it, preferably essentially in the adhesive plane, i.e. at a peel angle of about 0°, whereby it can be removed without leaving any residue and without damage.

[0136] However, a distance can also be achieved at other trigger angles such as 20° or 60°.

[0137] Manufacturing process

[0138] The adhesive compound for the self-adhesive article according to the invention is preferably applied to one side of a temporary carrier material L. The adhesive compound can be coated according to methods known to those skilled in the art, for example by means of a doctor blade process, a nozzle doctor blade process, or a roller nozzle process.

[0139] Extrusion die processes, casting die and casting processes. Also in accordance with the invention are coating processes such as roller coating processes, printing processes, screen printing processes, anilox roller processes, inkjet processes and spraying processes.

[0140] A preferred coating method is solvent-based. For this, the components of the pressure-sensitive adhesive are dissolved in a suitable solvent or solvent mixture, and the coating is then applied from the solution, after which the coated material is dried. Suitable solvents, which can also be used in combination, are aliphatic (e.g., pentane, hexane, heptane, dexamethasone, and their structural isomers), cycloaliphatic (e.g., cyclohexane and methylcyclohexane), and aromatic hydrocarbons (e.g., toluene, xylene), particularly in combination with ketones (e.g., acetone, 2-butanone, isobutyl ketone) or esters (e.g., ethyl acetate, butyl acetate, propyl acetate, isopropyl acetate). An advantageous procedure uses a mixture of toluene and ethyl acetate. A mixture of methylcyclohexane and an ester such as ethyl acetate or, in particular, butyl acetate is very advantageous.A mixture of cyclohexane and an ester, especially butyl acetate, is also advantageous.

[0141] Another preferred manufacturing method is hot melt processing, in which the pressure-sensitive adhesive is mixed using a compounding unit and, in particular, coated directly afterwards ("inline") by extrusion and / or die and / or calendering. Advantageously, the pressure-sensitive adhesive is first coated onto a temporary carrier material L and, in a second step, if such a layer is desired, laminated onto the carrier T, or the carrier T is laminated onto a release liner-free side of a pressure-sensitive adhesive layer. If necessary, further layers or material layers can be subsequently or previously laminated or coated inline or offline, so that multilayer product structures can also be produced. Such additional layers can introduce specific properties into the self-adhesive product, such as mechanical properties.They can also promote the bond between the adhesive and the carrier layer or suppress the migration of individual components from one layer to another. If a carrier layer T is used, another adhesive layer is laminated onto the side of the carrier layer opposite the first adhesive layer, or the composite containing the first adhesive layer and the carrier layer is laminated with a second adhesive layer on the side free of the release liner.

[0142] use

[0143] Finally, the present invention also includes the use of the self-adhesive article according to the invention for bonding to wall paint, wallpaper, in particular painted wallpaper, painted plasterboard, or plaster, in particular painted plaster. The adhesive compound and tape of the present invention are also particularly suitable for bonding to other uneven and / or easily splittable surfaces such as wood, wainscoting, veneer, panels, or wallboards. The present invention is explained in more detail with reference to the following examples, which are in no way to be understood as limiting the inventive concept.

[0144] Methods section - Description of the test methods

[0145] Unless explicitly stated otherwise, measurements are carried out under a test climate of 23 ± 1 °C and 50 ± 5 % relative humidity.

[0146] Tear resistance

[0147] The following adhesive tape samples were produced to test tear resistance. For all examples except E3, layers of the respective pressure-sensitive adhesives, each 100 pm thick, were applied to both sides of a 500 pm foam carrier (Alveolit ​​TMA SR 1000.5, polyethylene-based, density 95 kg / m³). 3 ) laminated. For example E3, a single-layer pattern of the pressure-sensitive adhesive layer with a layer thickness of 150 pm was used.

[0148] Twelve strips, each 10 mm wide and 54 mm long, are prepared from the laminate to be examined, and are shaped as an isosceles triangle over a length of 9 mm on one side.

[0149] These strips are glued to a polycarbonate sheet (cleaned and dried with ethanol) over a length of 45 mm using a first adhesive layer freed from the release liner. This ensures that a 10 mm long tab protrudes, positioned opposite the end of the strip that is pointed at the isosceles triangle (i.e., at the rectangular end of the strip). A second polycarbonate sheet is then applied to the second surface of the glued strips, after this too has been freed from the release liner, so that the two polycarbonate sheets are flush. The assembly is then rolled over 10 times with a 4 kg roller (five passes back and forth). After a 6-hour curing time, the strips are manually stripped from the adhesive joint at a speed of approximately 300 mm / min at a 180° angle. The two outermost adhesive strips were not considered in the evaluation.

[0150] The test assesses how many samples can be removed without leaving residue. Tear resistance is expressed as a percentage of torn adhesive strips. 100% corresponds to the case where none of 10 adhesive strips tore during a removal test performed by stretching. 10% corresponds to the case where only one of 10 adhesive strips did not tear during a removal test performed by stretching. Thermal shear strength (SAFT)

[0151] This test is used for the rapid testing of the shear strength of the respective adhesive layer under temperature stress. For this purpose, the adhesive layer to be tested is bonded to a temperature-controlled steel plate, loaded with a weight (50 g), and the shear distance is recorded.

[0152] Sample preparation:

[0153] The test sample consists of a 50 µm thick layer of pressure-sensitive adhesive applied to a 36 µm thick etched polyester film. The prepared adhesive tape is cut to a size of 10 mm x 50 mm.

[0154] The cut-to-size adhesive tape sample is placed with the other adhesive side onto a polished test plate cleaned with acetone (material 1.4301, DIN EN 10088-2, surface 2R, surface roughness R). aThe sample (30 to 60 nm, dimensions 50 mm * 13 mm * 1.5 mm) is bonded in such a way that the bonding surface of the sample measures 13 mm * 10 mm (height * width) and extends 2 mm beyond the test plate at the top edge. It is then rolled over six times with a 2 kg steel roller at a speed of 10 m / min to secure it. The sample is reinforced flush with the top surface with a strong adhesive strip, which serves as a support for the displacement sensor. Finally, the sample is suspended by the plate so that the longer protruding end of the adhesive strip points vertically downwards.

[0155] Measurement:

[0156] The sample to be measured is loaded at its lower end with a weight of 50 g. The test plate with the bonded sample is heated from 25 °C at a rate of 9 K / min to the final temperature of 200 °C.

[0157] The sample's slip path is monitored using a displacement sensor as a function of temperature and time. The maximum slip path is set at 1000 pm (1 mm); if this limit is exceeded, the test is terminated and the failure temperature is recorded. Test climate: room temperature 23 ± 3 °C, relative humidity 50 ± 5%. The result is the average of two individual measurements and is given in °C. Static shear strength

[0158] Shear strength at 40°C is a measure of the internal strength of the adhesive at elevated temperature and is tested in the so-called static shear test as follows: The test is performed according to PSTC-7 at 40°C using a 2 kg weight. A 1.3 cm wide strip of the sample (50 µm adhesive layer on 36 µm etched PET film) is bonded to a polished steel plate over a length of 2 cm using a 2 kg roller by double-rolling twice. The plates are equilibrated for 30 min under test conditions (40°C) but without a load. Then the test weight (2 kg) is attached so that a shear stress is applied parallel to the bonded area, and the time until the bond fails is measured. The measurement result is given in minutes as the shear life (SLR). The median of three individual measurements is reported. The test substrate is a polished steel plate.

[0159] Tilting shear test

[0160] Adhesive tape samples were produced as follows to test the holding performance. For all examples except E3, layers of the respective pressure-sensitive adhesive compound, each 100 pm thick, were applied to both sides of a 500 pm foam carrier (Alveolit ​​TMA SR 1000.5, polyethylene-based, density 95 kg / m³). 3 ) laminated. For example E3, a single-layer adhesive strip made of pressure-sensitive adhesive with a layer thickness of 150 µm was used. From the flat patterns, 3 strips measuring 20 mm x 50 mm, each provided on both sides at one end with a non-tacky gripping area (obtained by laminating 25 µm thick biaxially stretched polyester film measuring 20 mm x 13 mm), are first bonded to a substrate board prepared with gypsum plasterboard (painted with Caparol Supertäck 5 light matt, RAL1001) using a lambswool roller.

[0161] Using the applicator described in DE 102021126287 B3, the strips are pressed onto the second side of the strip with a pressure of 25 N by pulling the pressure edge of the applicator 5 times over the adhesive area of ​​the strip covered with a liner.

[0162] The liner on the second side of the strip is removed. A steel base plate measuring 40 mm x 20 mm x 3 mm (length x width x thickness) is glued to the center of the adhesive area. The adhesive bond is pressed for 5 seconds with 100 N. The laboratory hook is then slid onto the base plate. The hook's attachment mechanism to the base plate is identical to that of the tesa Powerstrips® Hook Large Classic with base plate (order number: TE-002105-ST). The laboratory hook has a steel pin at least 5 cm long, which is positioned centrally on the base plate. The test specimens are then subjected to a selected weight and lever arm by attaching the weight to the steel pin (15 N with a 30 mm lever arm). The time in days until the bond fails is determined. The test climate is 23 °C at 50% relative humidity. For many applications, the longer the time, the better.Once 25 days have passed, the test is stopped and the result is recorded as > 25 days.

[0163] DSC

[0164] Glass transition points – also known as glass transition temperatures – particularly of polymers or polymer blocks, are determined by measurements using Dynamic Scanning Calorimetry (DSC) according to DIN 53 765:1994-03, specifically sections 7.1 and 8.1, but with uniform heating and cooling rates of 10 K / min in all heating and cooling steps (see DIN 53 765:1994-03; section 7.1; note 1). The sample weight is 20 mg. The melting point or softening point of polymers or polymer blocks is also determined in this way.

[0165] softening temperature

[0166] For individual substances: The (adhesive) resin softening temperature (softening point; expansion point) is carried out according to the relevant methodology known as Ring & Ball and standardized according to ASTM E28.

[0167] DACP

[0168] Weigh 5.0 g of the test substance (the adhesive resin sample to be examined) into a dry vial and add 5.0 g of xylene (isomer mixture, CAS [1330-20-7], > 98.5%, Sigma-Aldrich #320579 or equivalent). Dissolve the test substance at 130 °C and then cool to 80 °C. Any evaporated xylene is replenished with more xylene to restore the total amount to 5.0 g. Next, add 5.0 g of diacetone alcohol (4-hydroxy-4-methyl-2-pentanone, CAS [123-42-2], 99%, Aldrich #H41544 or equivalent). Shake the vial until the test substance is completely dissolved. To achieve this, heat the solution to 100 °C. The sample vial containing the resin solution is then placed in a Novomatics Chemotronic Cool cloud point meter and heated to 110 °C. Cooling is performed at a rate of 1.0 K / min. The cloud point is then detected optically.The temperature at which the turbidity of the solution reaches 70% is recorded. The result is given in °C. The lower the DACP value, the higher the polarity of the test substance.

[0169] MMAP

[0170] 5.0 g of test substance (the adhesive resin sample to be examined) are weighed into a dry sample vial and mixed with 10 mL of dry aniline (CAS [62-53-3], > 99.5%, Sigma-Aldrich #51788 or equivalent) and 5 mL of dry methylcyclohexane (CAS [108-87-2], > 99%, Sigma-Aldrich #300306 or equivalent). The sample vial is shaken until the test substance is completely dissolved. For this purpose, the solution is heated to 100 °C. The sample vial containing the resin solution is then placed in a Novomatics Chemotronic Cool cloud point meter and cooled to 110 °C. Cooling is carried out at a rate of 1.0 K / min. The cloud point is detected optically. The temperature at which the turbidity of the solution reaches 70% is recorded. The result is given in °C. The lower the MMAP value, the higher the aromaticity of the test substance.

[0171] Molar mass (GPC)

[0172] Weight-average molar mass of adhesive resins and reinforcing resins:

[0173] The weight-average molecular weight M w The concentration is determined by gel permeation chromatography (GPC). THF is used as the eluent. The measurement is performed at 23 °C. PSS-SDV, 5 p, 10 is used as the guard column. 3 Ä, ID 8.0 mm x 50 mm is used. The columns PSS-SDV, 5 p, 10 are used for separation. 3 Ä and 10 4 A and 10 6 A sample with an ID of 8.0 mm x 300 mm was used. The sample concentration was 4 g / l, and the flow rate was 1.0 ml per minute. Calibration was performed using the commercially available ReadyCal kit for polystyrene high from PSS Polymer Standard Service GmbH, Mainz, Germany.

[0174] melt viscosity

[0175] To determine the melt viscosity of the soft resins, a shear stress sweep is performed in a rotating, shear-stress-controlled DSR 200 N rheometer from Rheometrics Scientific. A cone / plate measuring system with a diameter of 25 mm (cone angle 0.1002 rad) is used; the measuring head is air-bearing mounted and suitable for normal force measurements. The gap is 0.053 mm and the measuring temperature is 25 °C. The frequency is varied from 0.002 Hz to 200 Hz, and the melt viscosity is recorded at 1 Hz.

[0176] Tensile strength and elongation at break

[0177] Dumbbell-shaped test specimens are punched from the self-adhesive article to be tested using a die and a suitable press. Specimen type: 5A according to DIN EN ISO 527-2:2019-02. The two ends of the dumbbell-shaped test specimen are clamped in a tensile testing machine and stretched at a testing speed of 1000 mm / min until fracture. The clamping jaws are made of aluminum and are round. The round clamping jaws are designed to prevent the specimen from tearing in the area of ​​the clamping jaws. A sudden elongation step occurs in the area of ​​the clamping jaws. The clamped part of the test specimen cannot stretch, while the polymer chains in the rest of the specimen stretch. The shoulder is designed to counteract fracture in the area of ​​the sudden elongation step. The specimen must fracture in the middle. The free elongation length (clamping length) Lo* is equal to the parallel length of the specimen. Lo* is the initial distance between the centers of the clamping jaws. Lo* = 70 mm. The force is applied during the measurement.The tensile strength in MPa is the force in N per unit cross-sectional area in mm². 2 of the test specimen (web width x layer thickness), which is recorded in % at the elongation at break.

[0178] The thickness of each specimen is to be determined using a thickness gauge at one wide end and entered into the test program. A hand-held thickness gauge with an accuracy of 0.001 mm is used to determine the specimen thickness.

[0179] Test climate: 23 ±1 °C, 50 ± 5 % relative humidity.

[0180] thickness

[0181] The thickness of an adhesive layer, adhesive tape, adhesive article, substrate, or liner can be determined using commercially available thickness gauges (probe gauges) with accuracies of less than 1 pm deviation. The present application employs the precision thickness gauge Mod. 2000 F, which has a circular probe with a diameter of 50 mm (flat) in the case of foamed substrates or 10 mm (flat) in the case of adhesive layers. The measuring force is 4 N. The value is read 1 s after loading. If thickness variations are detected, the mean value of measurements at at least three representative locations is given, specifically excluding measurements taken at creases, folds, spots, and the like. The thickness of an adhesive layer can be determined, in particular, by measuring the thickness of a sample defined with respect to its length and width.

[0182] The section of such an adhesive layer applied to a substrate or liner is determined, minus the (known or separately determinable) thickness of a section of the same dimensions of the substrate or liner used.

[0183] I. Raw materials used

[0184] Table 2: Chemicals used

[0185] PS content: Polystyrene content

[0186] Extinction point: Softening point

[0187] II. Attempts

[0188] A series of test adhesive tape samples were produced.

[0189] Manufacturing process (hot melt process):

[0190] The samples were prepared from solution. The intended raw materials were weighed into a sample vial and mixed with a solvent mixture consisting of acetone, naphtha, and toluene (weight ratios 16:54:30 based on the total solvent quantity). The mixture was then left on a roller bench for 48 hours to obtain a 40% wt solution. The solutions were then coated onto a siliconized polyester release liner using a doctor blade and dried in a drying oven at 120°C for 15 minutes.

[0191] The thickness of the adhesive layers can be found in the respective descriptions of the sample preparation in the methods section for the different tests. Two 75 pm thick layers were laminated to form a 150 pm thick layer.

[0192] The dried coating was covered with another layer of a siliconized polyester release liner until further use.

[0193] A first layer of 100 µm pressure-sensitive adhesive was manually laminated to one side of a foam substrate using a rubber roller. A second layer of 100 µm pressure-sensitive adhesive was manually laminated to the other side of the foam substrate using a rubber roller and covered with a layer of siliconized release paper until further use.

[0194] Examples marked with "E" are examples according to the invention. Examples marked with "V" are comparative examples. Examples V2 and V3 reflect the prior art according to WO 2015195602 A1. Example V5 reflects the prior art according to EP 3362528 B1. For V4, no further testing was carried out and therefore the other values ​​were not determined (nb) because the composition was not tacky. For V5, the tear resistance was so low that the other tests were not carried out and their values ​​were therefore not determined (nb).

[0195] Table 3

[0196] Table 4

[0197] Table 5 Surprisingly, the examples according to the invention, comprising a reinforcing component and an adhesive resin with a DACP of 5 to 50 °C and an MMAP of 55 to 85 °C, in combination with the other components, show an improvement in tear resistance compared to a reference system without this reinforcing component or comprising an adhesive resin with an MMAP of less than 55 °C. At the same time, the examples according to the invention exhibit very good adhesion performance even on modern wall paints, as can be seen from the tilt shear test on the wall paint Caparol Supertäck 5, light matt, RAL 1001. Furthermore, the examples according to the invention exhibit high shear strengths, as can be seen from the shear life and the failure temperature SAFT.

Claims

Patent claims 1. Self-adhesive article comprising at least one layer H1 of an adhesive compound, characterized in that the adhesive compound contains the following components: (a) an elastomer component, and (b) an adhesive resin component, and (c) a reinforcing component, wherein the elastomer component (a) is at least one type of polyvinyl aromatic polybutadiene block copolymer P having a linear ABA structure or a linear (AB)2Z structure or radial (AB) n - Structural or radial (AB) n-Z structure with n > 3 and at least one type of diblock copolymer D with an AB structure or (AB)Z structure, wherein A represents polyvinyl aromatic compound, B represents polybutadiene and Z represents the derivative of a coupling substance, and wherein the polyvinyl aromatic compound content of the polyvinyl aromatic-polybutadiene block copolymer P is 20 to 40 wt.%, and wherein the adhesive resin component (b) is at least one adhesive resin having an MMAP of 55 to 85 °C, a DACP of 5 to 50 °C and a softening temperature of at most 130 °C, preferably at most 120 °C and at least 80 °C, and wherein the reinforcing component (c) is at least one resin having an MMAP of -10 °C to 30 °C, preferably 0 °C to 20 °C, and a softening temperature of at least 140 °C.

2. Self-adhesive article according to claim 1, characterized in that the elastomer component (a) comprises a total of 5 to 25 wt.%, based on the total weight of the Elastomer component (a) comprising at least one type of diblock copolymer D and a total of 75 to 95 wt.%, based on the total weight of the Elastomer component (a) containing at least one type of polyvinyl aromatic polybutadiene block copolymer P, wherein the sum of the amounts of diblock copolymer D and polyvinylaromatic polybutadiene block copolymer P in the elastomer component (a) is 90 to 100 wt.%, preferably 95 to 100 wt.%, particularly preferably 100 wt.%, based on the total weight of the elastomer component (a).

3. Self-adhesive article according to claim 1 or 2, characterized in that the adhesive compound contains 2 to 10 wt.%, preferably 2 to 8 wt.%, particularly preferably 2.5 to 8 wt.%, based on the total weight of the adhesive compound, the reinforcing component (c).

4. Self-adhesive article according to one of the preceding claims, characterized in that the adhesive compound contains 40 to 58 wt.%, based on the total weight of the adhesive compound, of the elastomer component (a).

5. Self-adhesive article according to one of the preceding claims, characterized in that the adhesive composition contains 25 to 55 wt.%, preferably 32 to 50 wt.%, particularly preferably 35 to 45 wt.%, based on the total weight of the adhesive composition, the adhesive resin component (b).

6. Self-adhesive article according to one of the preceding claims, characterized in that the softening temperature of the at least one resin of the reinforcing component (c) is at most 165 °C.

7. Self-adhesive article according to one of the preceding claims, characterized in that the at least one resin of the reinforcing component is at least one resin based on at least one, in particular aromatic, hydrocarbon compound, which is preferably selected from the group consisting of styrene, alpha-methylstyrene, para-methylstyrene and mixtures thereof, wherein the at least one resin of the reinforcing component preferably has a weight-average molecular weight M w from 1,000 g / mol to 15,000 g / mol, preferably from 2,000 g / mol to 10,000 g / mol, determined by GPC.

8. Removable self-adhesive articles according to one of the preceding claims, characterized in that the adhesive compound also contains a plasticizer component (d).

9. Self-adhesive article according to one of the preceding claims, characterized in that it additionally has a carrier layer T, wherein the carrier layer T is preferably foamed, wherein the foamed carrier layer preferably has a density of at most 150 kg / m³ 3 exhibits.

10. Self-adhesive article according to one of the preceding claims, characterized in that the polyvinyl aromatic blocks A of the diblock copolymers D and polyvinyl aromatic-polybutadiene block copolymers P are each polystyrene blocks.

11. Self-adhesive article according to one of the preceding claims, characterized in that the adhesive compound does not contain an adhesive resin which has a DACP of less than 5 °C and / or an MMAP of less than 55 °C and / or is a terpene-phenol resin.

12. Self-adhesive article according to claim 9, characterized in that the carrier layer T is foamed and the self-adhesive article has an elongation at break between 600 and 800 % and a minimum tensile strength of 4 MPa, each determined according to DIN EN ISO 527-2:2019-02.

13. Self-adhesive article according to claim 9, characterized in that the carrier layer T is foamed and the self-adhesive article has an elongation at break between 450 and 600 % and a minimum tensile strength of 5.5 MPa or an elongation at break between 400 and 450 % and a minimum tensile strength of 6.5 MPa, each determined according to DIN EN ISO 527-2:2019-02.

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