Pressure-sensitive adhesive compound

Abstract

The invention relates to the provision of a pressure-sensitive adhesive compound based on at least one block copolymer, said adhesive compound having good or improved properties, in particular temperature stability and aging stability, and being suitable for use in elevated temperature ranges. This is achieved by a pressure-sensitive adhesive compound based on at least one block copolymer BC which has at least one polymer block P(A) and at least one polymer block P(B), wherein - P(A) independently comprises homopolymer or copolymer blocks comprising a total of at least 80 wt.% of monomers A selected from the group consisting of methacrylic acid esters, methacrylamides, and monomers having at least one polymerisable vinyl group; - P(B) independently comprises homopolymer or copolymer blocks comprising a total of at least 80 wt.% of monomers B selected from the group consisting of methacrylic acid esters, methacrylamides, and monomers having at least one polymerisable vinyl group; characterised in that - the monomers A contain a total of at least 50 wt.% of one or more acrylate monomers A1 selected from the general structure CH2=C(H)(COOR1); where R1, in each occurrence, is independently selected from a linear or branched hydrocarbon group having 4 to 17 carbon atoms; - the monomers B comprise a total of at least 60 wt.% of one or more (meth)acrylamide monomers B1 selected from the general structure CH2=CR2-C(O)NR3R4; where R2, in each occurrence, is independently selected from H and CH3; R3, in each occurrence, is independently selected from the group consisting of alkyl groups, hydroxyalkyl groups, thioalkyl groups and acetonyl groups; and R4, in each occurrence, is independently selected from the group consisting of hydrogen, alkyl groups, hydroxyalkyl groups, aryl groups, amino alkyl groups, and acetonyl groups; or R3 and R4 together form an organic compound chain, so that NR3R4 is a ring having n ring atoms, where n is in the range of 5 to 8.

Description

[0001] Adhesive

[0002] The invention relates to pressure-sensitive adhesives based on at least one block copolymer, which are characterized by increased temperature stability and increased cohesion while simultaneously exhibiting high adhesive strength.

[0003] The demands on the stability of pressure-sensitive adhesives are constantly increasing. In particular, these adhesives are expected to exhibit excellent bonding properties even at high temperatures. To meet this need, (meth)acrylate block copolymers have emerged as a promising solution. These materials combine the advantageous properties of classic (meth)acrylate copolymers, such as aging resistance, water-clear transparency, and inherent tackiness, with the properties of styrene block copolymers, such as thermoreversible physical crosslinking and high cohesion.

[0004] Disadvantages of styrene block copolymer-based pressure-sensitive adhesives include, in the case of systems using unsaturated polymer chains in the elastomer block, e.g., when using styrene-isoprene-styrene (SIS) and styrene-butadiene-styrene (SBS) block copolymers, low resistance to aging from ultraviolet radiation, as well as to thermo-oxidative degradation and ozonolysis. Thus, the advantage of water-clear transparent self-adhesive tapes cannot be fully utilized, as the adhesive must be protected from light exposure. This is achieved, for example, through light-absorbing additives such as titanium dioxide, the compounding of which leads to opaque products. Styrene block copolymers with chemically saturated elastomer blocks, e.g.,While the hydrogenated analogues of SBS and SIS, styrene-ethylene / butylene styrene (SEBS) and styrene-ethylene / propylene styrene (SEPS), exhibit significantly improved aging resistance, typically do not require light-absorbing additives, and can therefore be more easily processed into water-clear products, a disadvantage is that they typically do not achieve the favorable ratio of bond strength to low re-release forces known from SIS- and SBS-based pressure-sensitive adhesives. Furthermore, without the use of plasticizing agents (e.g., liquid resins, aliphatic oils), which are desirable for many formulations, the selection of sufficiently compatible adhesive resins is considerably more limited compared to, for example, SIS.Commercially available block copolymers based on (meth)acrylates are limited by the choice of monomers used to form the various polymer blocks and the resulting glass transition temperature(s) of these blocks. Typically, commercially available block copolymers feature polymethyl methacrylate (PMMA) as the monomer of the hard (polymer) block, i.e., the block with a high glass transition temperature, and exhibit heat resistance that is also attributable to the glass transition temperature of PMMA. The limited use of monomers in commercial block copolymers means that the desired properties at high temperatures cannot be fully achieved. Therefore, there is a need for new, alternative block copolymer systems based on (meth)acrylates that exhibit very good or improved properties, particularly at high temperatures.

[0005] Several studies have been conducted on processes involving polar monomers, such as methacrylic or acrylic esters, in anionic polymerization. However, such polar monomers possess a residue, such as a carbonyl group, which is readily susceptible to nucleophilic attack. Therefore, achieving optimal conditions for viable polymerization during the anionic polymerization of a polar monomer is relatively difficult, as a side reaction of the monomer or an intermolecular cyclization reaction (so-called "backbiting") occurs at the growing end of the resulting polymer. Consequently, the selection of suitable monomers is limited, necessitating the development of alternative block copolymers based on different building blocks. Furthermore, anionic polymerization places very high demands on the reaction conditions, reaction control, and reactant purity.

[0006] There is a need for adhesive tapes that exhibit very high bond strength but also retain their cohesion at elevated temperatures. Particularly in outdoor applications, in automobiles, and in electronic, optical, and / or precision mechanical devices, temperatures of up to 70 °C or higher can occur.

[0007] The object of the invention is to provide an adhesive based on at least one block copolymer comprising essentially (meth)acrylic acid derivatives, which exhibits good adhesive strength, particularly on polar substrates, as well as good shear strength, especially good shear strength at elevated temperatures. A first and general object of the invention, with which these objects are achieved, is an adhesive based on at least one block copolymer BC comprising at least one polymer block P(A) and at least one polymer block P(B), wherein

[0008] P(A) independently comprising homo- or copolymer blocks comprising a total of at least 80 wt.% monomers A selected from the group consisting of methacrylic esters, methacrylamides and monomers with at least one polymerizable vinyl group;

[0009] P(B) independently comprising homo- or copolymer blocks comprising a total of at least 80 wt.% monomers B selected from the group consisting of methacrylic acid esters, methacrylamides and monomers with at least one polymerizable vinyl group; characterized in that the monomers A comprise a total of at least 50 wt.% one or more acrylate monomers A1 (“monomers A1”) selected from the general structure CH2=C(H)(COOR 1 ) include; where R 1 in each occurrence is independently selected from a linear or branched alkyl group with 4 to 17 carbon atoms (C atoms);

[0010] - the monomers B comprise at least 60 wt% of one or more (meth-)acrylamide monomers B1 (“monomers B1”) selected from the general structure CH2=CR 2 -C(O)NR 3 R 4 include; whereby

[0011] R 2 The selection for each occurrence is independently of each other from H and CH3;

[0012] R 3 In each occurrence, it is independently selected from the group consisting of alkyl groups, hydroxyalkyl groups, thioalkyl groups, and acetonyl groups; and R 4 selected independently for each occurrence from the group consisting of hydrogen, alkyl groups, hydroxyalkyl groups, aryl groups, aminoalkyl groups and acetonyl groups; or R 3 and R 4 together they form an organic chain of compounds, such that NR 3 R 4 a ring with n ring atoms, where n is in the range of 5 to 8.

[0013] The adhesive compound according to the invention is suitable for use at elevated temperatures, in particular in the temperature range up to at least 70 °C.

[0014] Details and embodiments of the invention are described below. Such embodiments, which are subsequently designated as preferred in any form, are combined in particularly preferred embodiments with features of other embodiments also designated as preferred in any form. Combinations of two or more of the embodiments subsequently designated as particularly preferred in any form are therefore especially preferred. Also preferred are embodiments in which a feature of one embodiment designated as preferred in any degree is combined with one or more further features of other embodiments designated as preferred in any degree.

[0015] Insofar as specific quantities or proportions of an element as well as preferred embodiments of the element are disclosed below, the specific quantities or proportions of the preferably embodiments are also disclosed. Furthermore, it is disclosed that, among the corresponding specific total quantities or proportions of the elements, at least some of the elements may be preferably embodiments, and in particular, that preferably embodiments may, in turn, be present within the specific total quantities or proportions.

[0016] In accordance with professional understanding, an adhesive is an adhesive that possesses pressure-sensitive properties, meaning it forms a permanent bond to a substrate even under relatively light pressure. Such adhesives or pressure-sensitive tapes are generally permanently tacky even at room temperature, meaning they exhibit a certain viscosity and tackiness, allowing them to wet the surface of a substrate even with minimal pressure. While not bound to this theory, it is often assumed that an adhesive can be considered an extremely highly viscous liquid with an elastic component, which consequently exhibits characteristic viscoelastic properties that lead to the permanent tackiness and pressure-sensitive adhesion described above.It is assumed that pressure-sensitive adhesives undergo mechanical deformation, resulting in both viscous flow processes and the development of elastic restoring forces. The viscous flow contributes to adhesion, while the elastic restoring forces are essential for cohesion. The relationships between rheology and pressure sensitivity are well-established in the art and are described, for example, in "Satas, Handbook of Pressure Sensitive Adhesives Technology," Third Edition, (1999), pages 153 to 203. The storage modulus (G') and the loss modulus (G") are typically used to characterize the degree of elastic and viscous components. These values ​​can be determined using dynamic mechanical analysis (DMA), for example, with a rheometer.Within the scope of the present invention, an adhesive compound is preferably understood to be adhesive and thus a pressure-sensitive adhesive compound if, at a temperature of 23 °C in the deformation frequency range of 10° to 10. 1 rad / sec G' and G" each at least partially in the range of 10 3 up to 10 7 Pa lie.

[0017] Block copolymers are macromolecules consisting of two or more covalently linked polymer blocks, for example, polymer block A "P(A)" and polymer block B "P(B)". The adjacent polymer blocks consist of constitutional units derived from different monomer species or from the same monomer species but with different compositions or sequence distributions of constitutional units. The specific molecular structure of the blocks usually results in microphase separation and thus in the formation of morphologies at the nanoscale level.

[0018] The block copolymer according to the invention is a polymer system. According to the invention, the term "polymer system" refers to both a single polymer and a mixture of two or more different polymers. In accordance with the skilled person's understanding, a "polymer" or "a single polymer" is understood to mean not only a single macromolecule, but also a plurality of macromolecules that originate from one and the same polymerization process and exhibit a specific molar mass distribution among themselves.

[0019] The pressure-sensitive adhesive according to the invention is based on at least one block copolymer BC. "Based on" or "on the basis of" or "based on" means in this context that the properties of the pressure-sensitive adhesive are at least strongly determined by the fundamental properties of the at least one block copolymer BC, whereby it is of course not excluded that these properties may be further influenced by the use of modifying auxiliaries or additives in a composition. In particular, this may mean that the proportion of the at least one block copolymer BC in the total mass of the pressure-sensitive adhesive is more than 50% by weight.

[0020] In one embodiment, the adhesive compound according to the invention comprises at least one block polymer BC to at least 50 wt.%, preferably to at least 60 wt.%, particularly preferably to 70 wt.% based on the total weight of the adhesive compound.

[0021] The block copolymer BC comprises at least one polymer block (A) and at least one polymer block P(B). Each polymer block P(A) independently represents a homoblock or copolymer block comprising monomer A. Each polymer block P(B) independently represents a homoblock or copolymer block comprising monomer B. The at least one polymer block P(A) comprises homoblocks or copolymer blocks containing at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 95 wt%, at least 98 wt%, or 100 wt% monomer A selected from the group consisting of methacrylic esters, methacrylamides, and monomers with at least one polymerizable vinyl group.

[0022] The at least one polymer block P(B) comprises homo- or copolymer blocks which contain a total of at least 80 wt.%, at least 85 wt.%, at least 90 wt.%, at least 95 wt.%, at least 98 wt.% or 100 wt.% monomers B selected from the group consisting of methacrylic esters, methacrylamides and monomers with at least one polymerizable vinyl group.

[0023] In one embodiment, the at least one polymer block P(A) has a glass transition temperature of < 0 °C, more preferably of < -10 °C, in particular of < - 20 °C, wherein the glass transition temperature of the at least one polymer block P(A) is determined according to the Fox equation (G1 ).

[0024] In one embodiment, the at least one polymer block P(B) has a glass transition temperature of > 50 °C, more preferably of > 70 °C, in particular of > 90 °C, wherein the glass transition temperature of the at least one polymer block P(B) is determined according to the Fox equation (G1 ).

[0025] In a preferred embodiment, the at least one polymer block P(A) has a glass transition temperature of < 0 °C, more preferably of < -10 °C, in particular of < -20 °C, and the at least one polymer block P(B) has a glass transition temperature of > 50 °C, more preferably of > 70 °C, in particular of > 90 °C, wherein the glass transition temperature of the at least one polymer block P(A) and the at least one polymer block P(B) is determined according to the Fox equation (G1).

[0026] The glass transition temperature of polymers, such as poly(meth)acrylates and in the present case polymer blocks such as P(A) and P(A), can be determined using the Fox equation (G1 )

[0027] 1 = y W n TT (G1) 'G n G,n

[0028] (cf. TG Fox, Bull. Am. Phys. Soc. 1 (1956) 123). In equation G1, n represents the number of iterations over the monomers used, w n the mass fraction of the respective monomer n (wt%) and T G , n the respective glass transition temperature of the homopolymer made from the respective monomers n in Kelvin.

[0029] Unless otherwise specified, the glass transition temperatures of monomers are determined using Method 1 (see section Measurement and Testing Methods). The polymer blocks P(A), as described in the main claim or in advantageous embodiments, can be polymer chains of a single monomer type from monomers A or copolymers of monomers with different structures from monomers A. In particular, the monomers A used can vary in their chemical structure and / or in the length of the alkyl group. The polymer blocks thus encompass the range from completely homogeneous polymers to polymers of monomers with the same basic chemical structure but different chain lengths, and those with the same number of carbon atoms but different isomers, up to statistically polymerized blocks of monomers of different lengths and isomerism from the group of monomers A.The same applies to the polymer blocks P(B) with respect to the monomers B.

[0030] An advantageous embodiment is if the block copolymers have a symmetrical structure such that polymer blocks P(A) and / or polymer blocks P(B) are identical in chain length and / or chemical structure.

[0031] Furthermore, all "asymmetrical" structures are also included, in which all of the polymer blocks P(A) and P(B) that occur fulfill the above-mentioned criteria on their own, but the chemical or structural identity of the individual building blocks is not a requirement.

[0032] The block copolymer according to the invention, which is present in at least two phases, comprises at least one polymer block P(A) and at least one polymer block P(B). Each polymer block P(A) independently represents a homoblock or copolymer block of monomer A, wherein the monomers A comprise one or more monomers selected from the group consisting of methacrylic esters, methacrylamides, and monomers with at least one polymerizable vinyl group. Each polymer block P(B) independently represents a homoblock or copolymer block of monomer B, wherein the monomers B comprise one or more monomers selected from the group consisting of methacrylic esters, methacrylamides, and monomers with at least one polymerizable vinyl group.

[0033] The monomers A comprise one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides, and monomers with at least one polymerizable vinyl group, comprising at least 80 wt.%, alternatively 85 wt.%, more preferably at least 90 wt.%, and particularly preferably at least 95 wt.%, and especially at least 98 wt.%. Most preferably, the monomers A comprise exclusively one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides, and monomers with at least one polymerizable vinyl group. The monomers A according to the invention comprise, in total, at least 50 wt.%, based on the total weight of the monomers A, one or more acrylate monomers A1 selected from the general structure CH2=C(H)(COOR). 1 ); where R 1 Each occurrence is independently selected from a linear or branched alkyl group with 4 to 17 carbon atoms.

[0034] In further embodiments, the monomers A according to the invention comprise one or more monomers A1 in total at least 75 wt.%, at least 85 wt.%, at least 90 wt.%, at least 95 wt.%, at least 98 wt.% or 100 wt.% based on the total weight of the monomers A.

[0035] In one embodiment, the monomers A1 are selected from the group consisting of n-butyl acrylate, iso-butyl acrylate, iso-amyl acrylate, n-hexyl acrylate, n-heptyl acrylate, 2-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, iso-octyl acrylate, n-nonyl acrylate, iso-nonyl acrylate, 2-propylheptyl acrylate, n-decyl acrylate, iso-decyl acrylate, lauryl acrylate, tetradecyl acrylates, heptadecyl acrylate.

[0036] The monomers B comprise one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides, and monomers with at least one polymerizable vinyl group, comprising at least 80 wt.%, alternatively 85 wt.%, more preferably at least 90 wt.%, and particularly preferably at least 95 wt.%, and especially at least 98 wt.%. Most preferably, the monomers B comprise exclusively one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides, and monomers with at least one polymerizable vinyl group.

[0037] The monomers B according to the invention comprise at least 60 wt% of one or more (meth)acrylamides B1 selected from the general structure CH2=CR 2 - C(O)NR 3 R 4 include; where R 2 selected independently from H and CH3 for each occurrence; R 3In each occurrence, it is independently selected from the group consisting of alkyl groups, hydroxyalkyl groups, thioalkyl groups, and acetonyl groups; and R 4 selected independently for each occurrence from the group consisting of hydrogen, alkyl groups, hydroxyalkyl groups, aryl groups, aminoalkyl groups and acetonyl groups; or R 3 and R 4 together they form an organic chain of compounds, such that NR 3 R 4 a ring with n ring atoms, where n is in the range of 5 to 8.

[0038] Thus, the one or more (meth-)acrylamide monomers B1 can form symmetrical amides (R 3 is equal to R 4 ), asymmetric amides (R 3 is not equal to R 4 ) and form cyclic amides in which the -NR 3 R 4 The substituent is an optionally substituted cyclic group with 5 to 8 ring atoms, where R 3 and R 4together form an organic compound chain. According to the invention, the cyclic groups can be 5-, 6-, 7- or 8-rings, wherein the resulting ring structure is always bound via the amide nitrogen according to the general structure of the monomers B1.

[0039] Examples of the amides (meth-)acrylamide monomers B1 according to the invention include dimethylacrylamide as a symmetric amide; N-sec-butylacrylamide, N-tert-butylacrylamide, N-(3-nitrophenyl)acrylamide, N-iso-propylacrylamide, N-(3-(dimethylamino)propyl)acrylamide) and N-1-naphthylacrylamide as asymmetric amides; 4-acryloylmorpholine or piperidine acrylamide as cyclic amides.

[0040] In embodiments in which R 3 and R 4Together forming an organic compound chain, the monomers B1, in addition to nitrogen and carbon as ring atoms, optionally include further organic ring atoms such as oxygen or sulfur. In a preferred embodiment, the organic compound chain, besides nitrogen and carbon, includes at most one ring atom; preferably exactly one ring atom; selected from the group consisting of oxygen or sulfur. Particularly preferably, the organic compound chain, in addition to the bonded amide nitrogen according to the general structure B1 and the further carbon ring atoms, includes exactly one oxygen ring atom.

[0041] In embodiments in which R 3 and R 4 together they form an organic chain of compounds, as the NR points out. 3 R 4 -Substitute 3 to 10, preferably 4 to 6, more preferably 4 or 5, in particular preferably exactly 4 carbon atoms.

[0042] In this document, the number of carbon atoms of a substituent refers to the total number of carbon atoms present in the substituent, including any optional additional substituents. Thus, for example, a norbornyl group is a cyclic carbon group with 7 carbon atoms, an isobornyl group is a cyclic carbon group with 10 carbon atoms, an adamantyl group is a polycyclic group with 10 carbon atoms, and a dicyclopentanyl group is a polycyclic group with 10 carbon atoms. If a norbornyl group were substituted with a CN group, this would be described as a cyclic group with 8 carbon atoms.

[0043] In one embodiment, the monomers B according to the invention comprise a total of at least 60 wt.% one or more (meth-)acrylamide monomers B1 selected from the general structure CH2=CR 2 -C(O)NR 3 R 4 ; where R 2 equal to H or CH3, preferably H; R 3The group selected independently for each occurrence is from alkyl groups, preferably with 1 to 10 carbon atoms, particularly preferably with 1 to 6 carbon atoms; R 4 selected from the group consisting of hydrogen and alkyl groups, preferably with 1 to 10 carbon atoms, particularly preferably with 1 to 6 carbon atoms; or R 3 and R 4 together they form an organic chain of compounds, such that NR 3 R 4 a six-membered ring - i.e., one that has 6 ring atoms - which optionally contains oxygen or sulfur as one of the 6 ring atoms, in addition to nitrogen and carbon.

[0044] Acrylamides have a higher hydrolysis stability compared to acrylates, which is why a high proportion of acrylamide has a beneficial effect on hydrolytic resistance.

[0045] In a preferred embodiment, the monomers B comprise a total of at least 60 wt.% one or more (meth)acrylamide monomers B1 selected from the general structure CH2=CR 2 -C(O)NR 3 R 4 ; where R 2 equal to H or CH3, preferably H; R 3 Each occurrence is independently selected from alkyl groups with 1 to 4 carbon atoms; R 4 selected is from the group consisting of hydrogen and alkyl groups with 1 to 4 carbon atoms; or R 3 and R 4 together they form an organic chain of compounds, such that the monomers B1 have a structure according to formula B1-1:

[0046] Formula B1 -1 where X is selected from the group consisting of O, S and CH2.

[0047] In one embodiment, the monomers B1 are selected from the group consisting of dimethylacrylamide, 4-acryloylmorpholine, N-sec-butylacrylamide, N-tert-butylacrylamide, piperidineacrylamide, N-(3-nitrophenyl)acrylamide, N-iso-propylacrylamide, N-(3-(dimethylamino)propyl)acrylamide), N-1-naphthylacrylamide.

[0048] 4-Acryloylmorpholine (“ACMO”) refers to the molecule with IIIPAC designation 1-(morpholine-4-yl)propenone and CAS number 5117-12-4, and thus the molecule according to formula B1-1, where X is equal to O.

[0049] In further embodiments, the monomers B according to the invention comprise one or more monomers B1 in a total of at least 75 wt.%, at least 85 wt.%, at least 90 wt.%, at least 95 wt.%, at least 98 wt.%, or at 100 wt.% based on the total weight of the monomers B. Surprisingly, good adhesive strengths and shear strengths are observed for the (meth)acrylamide compounds, preferably acrylamide compounds, as monomers B1, which were alternatively only achieved with methacrylate compounds or styrene.

[0050] Furthermore, acrylate compounds and acrylamides are characterized by their good commercial availability.

[0051] In a preferred embodiment, the monomers B1 are selected from the group consisting of 4-acryloylmorpholine, dimethylacrylamide, N-iso-propylacrylamide, N-(3-dimethylamino)propylacrylamide) and N-tert-butylacrylamide.

[0052] In a particularly preferred embodiment, the monomers B1 are equal to 4-acryloylmorpholine.

[0053] The block copolymer according to the invention is a polymer system which preferably exists in at least two phases. Those skilled in the art understand this to mean that one phase is rich in, or essentially consists of, one component of the block copolymer, for example, polymer block P(A), and the other phase is rich in, or essentially consists of, another component, for example, polymer block P(B). The presence of small amounts of one component in the other, which does not preclude the formation of multiphases, is considered negligible. If the block copolymer according to the invention has more than two phases, the foregoing applies accordingly to all of these phases.

[0054] The phase separation is particularly preferably realized such that discrete regions (“domains”) rich in polymer block P(A) or polymer block P(B) – i.e., essentially composed of polymer block P(A) or polymer block P(B) – are present in a continuous matrix rich in the other polymer block – i.e., essentially composed of the other polymer block. A block copolymer according to the invention is considered to be present in at least two phases, in particular, if at least one of the following criteria a) - c) is met: a) Phase boundaries are discernible in a height profile analysis or an analysis of the Young's modulus from an atomic force microscopy (AFM) image of the block copolymer. b) At least two independent glass transition temperatures are obtained from a differential scanning calorimetry (DSC) measurement performed on the block copolymer.c) At least two tan θ maxima are obtained from a Dynamic Mechanical Analysis (DMA) performed on the block copolymer. According to the invention, a block copolymer BC existing in at least two phases also comprises a microphase-separated block copolymer, i.e., a polymer system in which the discontinuous phase is present in a microscopically fine distribution.

[0055] In one embodiment, the adhesive compound according to the invention is based on at least one block polymer BC present in at least two phases.

[0056] The process according to the invention is intended to result in a polymer system consisting of at least two phases. Furthermore, it was an objective of the invention to provide the two- or multi-phase polymer system with the highest possible cohesion. Therefore, it seemed important to consider these and, if applicable, other properties of the final polymer system when selecting the monomers used in the two polymerization steps.

[0057] Monomers with a glass transition temperature of the homopolymer in question of < 0 °C, more preferably of < -10 °C, particularly of < -20 °C, i.e., monomers that are particularly suitable for the polymer block P(A), are selected, for example, from the group consisting of ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, iso-amyl acrylate, n-hexyl acrylate, 2-heptyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, iso-octyl acrylate, n-nonyl acrylate, iso-nonyl acrylate, 2-propylheptyl acrylate, n-decyl acrylate, iso-decyl acrylate, lauryl acrylate, 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate, 2-cyanoethyl acrylate, 2- (2-Ethoxyethoxy)ethyl acrylate, phenoxyethyl acrylate, iso-stearyl acrylate, docosyl acrylate, and 2-[2-(2-Methoxyethoxy)-ethoxy]ethyl acrylate.

[0058] Monomers with a glass transition temperature of the homopolymer in question of > 50 °C, more preferably of > 75 °C, particularly of > 100 °C, i.e., monomers that are particularly suitable for the polymer block P(B), are selected, for example, from the group consisting of dicyclopentanyl acrylate, isobornyl acrylate, norbornyl acrylate, benzyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, cyclohexyl acrylate, 4-[(6-acryloyloxy)hexyloxy]4'-cyanobiphenyl, N-succinimidyl acrylate, 1-ethylcyclopentyl acrylate, N-tert-octylacrylamide, N-tert-butylacrylamide, dimethylacrylamide, diethylacrylamide, acrylamide, N-[3-(dimethylamino)propyl]acrylamide, diacetone acrylamide, N-(butoxymethyl)acrylamide, N-phenylacrylamide. N-[2-(Dimethylamino)ethyl]acrylamide, N-[2-(Diethylamino)ethyl]acrylamide, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, glycerol formal methacrylate, 2-dimethylaminoethyl methacrylate, phenoxyethyl methacrylate, 9-anthrylmethyl methacrylate,2-Ethyl-2-adamantylmethacrylat, 2- (Acetoacetyloxy)ethylmethacrylat, 2-lsopropyl-2-methacryloyloxyadamantan, iso- Propylmethacrylat, iso-Butylmethacrylat, tert-Butylmethacrylat, Furfurylmethacrylat, 2- Methacryloyloxy-2-methyladamantan, Phenylmethacrylat, N-Succinimidylmethacrylat, 2-(tert- Butylamino)ethylmethacrylat, 2-Cyclohexylpropan-2-ylmethacrylat, 1 -Adamantylmethacrylat, 1 -Methylcyclopentylmethacrylat, 3-Dimethylaminopropylmethacrylamid, N-tert- Butylmethacrylamid, N-(Methoxymethyl)methacrylamid, N,N-Dimethylmethacrylamid, Methacrylamid, N-Phenylmethacrylamid, N,N-Dimethylmethacrylamid, N-Vinylformamid, N- Vinylpyrrolidon, N-Vinylcaprolactam, N-Vinylcarbazol, N-Vinylimidazol, Vinylmethyloxazolidinon und N-Vinyl-N-methylacetamid.,

[0059] Against this background, in one embodiment of the invention, the monomers A comprise at least 50 wt.%, more preferably at least 60 wt.%, in particular at least 75 wt.%, of one or more monomers with a glass transition temperature of the homopolymer in question of < 0 °C, more preferably of < -10 °C, in particular of < -20 °C; and the monomers B comprise at least 60 wt.%, more preferably at least 70 wt.%, in particular at least 80 wt.%, of one or more monomers with a glass transition temperature of the homopolymer in question of > 50 °C, more preferably of > 75 °C, in particular of > 100 °C, most preferably of > 120 °C, wherein - unless otherwise specified - the glass transition temperatures are determined by means of method 1 (see section Measurement and Testing Methods).

[0060] In a further embodiment of this embodiment, the monomers A preferably comprise a total of at least 50 wt.%, more preferably a total of at least 60 wt.%, in particular a total of at least 75 wt.% one or more monomers A1 and the monomers B comprise a total of at least 60 wt.%, more preferably a total of at least 70 wt.%, in particular a total of at least 80 wt.% one or more monomers B1 .

[0061] More preferably, the monomers A comprise a total of at least 50 wt.%, more preferably a total of at least 60 wt.%, and in particular a total of at least 75 wt.%, one or more monomers selected from the group consisting of n-butyl acrylate, iso-amyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, iso-octyl acrylate, n-octyl acrylate, iso-nonyl acrylate, nonyl acrylate, 2-propylheptyl acrylate, n-decyl acrylate, iso-decyl acrylate, lauryl acrylate; and heptadecyl acrylate, the monomers B comprise a total of at least 60 wt.%, more preferably a total of at least 70 wt.%, and in particular a total of at least 80 wt.%, one or more monomers selected from the group consisting of dimethylacrylamide, 4-acryloylmorpholine, N-sec-butylacrylamide, N-tert-butylacrylamide, piperidineacrylamide, N-(3-nitrophenyl)acrylamide, N-iso-propylacrylamide, N-(3-(dimethylamino)propyl)acrylamide), N-1-naphthylacrylamide.

[0062] In a further development of this embodiment, the monomers A preferably comprise a total of at least 50 wt.%, more preferably a total of at least 60 wt.%, in particular a total of at least 75 wt.% one or more monomers A1, a total of up to 35 wt.%, more preferably a total of up to 25 wt.%, in particular a total of up to 20 wt.% one or more monomers selected from the group consisting of dimethylacrylamide, 4-acryloylmorpholine, N-sec-butylacrylamide, N-tert-butylacrylamide, piperidineacrylamide, N-(3-nitrophenyl)acrylamide, N-iso-propylacrylamide, N-(3-(dimethylamino)propyl)acrylamide and N-1-naphthylacrylamide, and a total of up to 10 wt.% one or more functionalized monomers; and the monomers B comprise at least 60 wt.%, more preferably at least 70 wt.%, and in particular at least 80 wt.%, one or more monomers B1; and a maximum of 10 wt.%.-% one or more functionalized monomers, wherein the functionalized monomers are selected from the group consisting of hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 2-hydroxyethyl acrylamide, 4-hydroxyethyl acrylamide, acrylic acid, methacrylic acid, 2-acryloyloxyethyl succinate, methacryloxyethyl succinate, sulfoethyl methacrylate, acrylamide, methacrylamide, glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl methyl acrylate, 3,4-.

[0063] Epoxycyclohexylmethyl methacrylate, 4-hydroxybutylacrylate glycidyl ether, 4-hydroxybutyl methacrylate glycidyl ether, isocyanatoethyl acrylate, isocyanatoethyl methacrylate, 2-[2-(methacryloyloxy)ethyloxy]ethyl isocyanate, 2-[2-(acryloyloxy)ethyloxy]ethyl isocyanate and a,a- Dimethyl m-isopropenyl benzyl isocyanate.

[0064] In particular, the monomers A comprise a total of at least 50 wt.%, more preferably a total of at least 60 wt.%, and in particular a total of at least 75 wt.%, one or more monomers selected from the group consisting of n-butyl acrylate, iso-amyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, iso-octyl acrylate, n-octyl acrylate, 2-propylheptyl acrylate, n-decyl acrylate and iso-decyl acrylate; to a maximum total of 35 wt.%, more preferably to a maximum total of 25 wt.%, in particular to a maximum total of 20 wt.%, one or more monomers selected from the group consisting of dimethylacrylamide, 4-acryloylmorpholine, N-sec-butylacrylamide, N-tert-butylacrylamide, piperidineacrylamide, N-(3-nitrophenyl)acrylamide, N-iso-propylacrylamide, N-(3-(dimethylamino)propyl)acrylamide) and N-1-naphthylacrylamide, and to a maximum total of 10 wt.%.-% one or more monomers selected from the group consisting of acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 3,4-epoxycyclohexyl methyl acrylate, 3,4-.

[0065] Epoxycyclohexylmethyl methacrylate, glycidyl acrylate and glycidyl methacrylate; and the monomers B comprise, to a total of at least 60 wt.%, more preferably to a total of at least 70 wt.%, and in particular to a total of at least 80 wt.%, one or more monomers selected from the group consisting of dimethylacrylamide, 4-acryloylmorpholine, N-sec-butylacrylamide, N-tert-butylacrylamide, piperidine acrylamide, N-(3-nitrophenyl)acrylamide, N-iso-propylacrylamide, N-(3-(dimethylamino)propyl)acrylamide) and N-1-naphthylacrylamide; and to a total of at most 10 wt.%, one or more monomers selected from the group consisting of acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate,

[0066] Hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 3,4-epoxycyclohexyl methyl acrylate, 3,4-epoxycyclohexyl methyl methacrylate, glycidyl acrylate and glycidyl methacrylate.

[0067] In one embodiment, the monomers A and monomers B comprise a total of a maximum of 15 wt.%, preferably a total of a maximum of 10 wt.%, and particularly preferably a total of a maximum of 5 wt.% methyl methacrylate.

[0068] In a further development of this embodiment, at least the monomers B are essentially free of methyl methacrylate; more preferably, they are free of methacrylic acid esters and methacrylamides; in particular, they are free of any methacrylic compounds.

[0069] Preferably, the monomers A are essentially free of methyl methacrylate; more preferably, they are free of methacrylic acid esters and methacrylamides; in particular, they are free of any methacrylic compounds.

[0070] In a further development of these embodiments, monomers A and monomers B are essentially free of methyl methacrylate; more preferably, they are free of methacrylic acid esters and methacrylamides; in particular, they are free of any methacrylic compounds.

[0071] Essentially free of methyl methacrylate means that the monomers (A and / or B) contain less than 1 wt.%, preferably less than 0.5 wt.%, based on the total composition of methyl methacrylate, and particularly preferably no methyl methacrylate.

[0072] Currently available products with pressure-sensitive adhesives based on styrene block copolymers exhibit weaknesses in bond strength at temperatures above 50 °C. Due to the softening of the hard phases (block polystyrene domains), which consist primarily of polystyrene, the adhesive strips cohesively fail, particularly when bonding medium-weight objects.

[0073] In one embodiment, the monomers A and monomers B comprise a total of a maximum of 15 wt.%, preferably a total of a maximum of 10 wt.%, and particularly preferably a total of a maximum of 5 wt.% styrene.

[0074] In a further development of this embodiment, at least the monomers B are essentially free of styrene.

[0075] The monomers A are preferably essentially free of styrene.

[0076] In a further development of these embodiments, monomers A and monomers B are essentially free of styrene.

[0077] Essentially free of methyl methacrylate means that the monomers (A and / or B) contain less than 1 wt.%, preferably less than 0.5 wt.%, based on the total composition of styrene, and particularly preferably no styrene.

[0078] As has been shown, the exclusion of the aforementioned compounds (methacrylic compounds and / or styrene) has a beneficial effect on the polymerization rate.

[0079] In one embodiment, the block copolymer contains less than 17 wt% isobornyl acrylate.

[0080] In a preferred embodiment, the monomers B are not isobornyl acrylate. Allergic contact dermatitis has been observed with adhesives containing isobornyl acrylate when applied to the skin and in close-contact applications (such as watches / smartwatches).

[0081] In one embodiment, the block copolymer BC has a weight-average molar mass M w > 200,000 g / mol, preferably M w s 350,000 g / mol, particularly preferred M w s 500,000 g / mol. In one embodiment, the block copolymer BC has a polydispersity PD greater than 2, alternatively greater than 4 or greater than 6.

[0082] In one embodiment, the at least one polymer block P(A) and / or the at least one polymer block P(B) has a weight-average molar mass Mw > 100,000 g / mol, preferably Mw > 150,000 g / mol, particularly preferably Mw > 200,000 g / mol.

[0083] In one embodiment, the block copolymer BC exists as a multimodal block copolymer. A multimodal block copolymer is understood to be a block copolymer with at least a bimodal mass distribution, i.e., a molar mass distribution with at least two maxima.

[0084] In one embodiment, the block copolymer BC comprises polymer blocks P(B) in a proportion between 5 and 49 wt.%; preferably between 7.5 and 35 wt.%; in particular between 10 and 30 wt.%, most preferably between 12 and 28 wt.%; based on the totality of polymer blocks P(A) and P(B) of the block copolymer BC.

[0085] The ratios of the chain lengths of the block copolymers P(A) to those of the block copolymers P(B) are advantageously selected such that the block copolymers P(B) exist as a dispersed phase ("domains") within a continuous matrix of polymer blocks P(A). This is preferably the case when the polymer block content P(B) is less than approximately 35 wt.%. The formation of hexagonally packed cylindrical domains of the polymer blocks P(B) is also possible according to the inventive teaching, but is usually not preferred due to the less favorable tensile / elongation characteristics of such materials and the structural anisotropy of the resulting pressure-sensitive adhesives induced by the domain structure.By using an asymmetric design of the triblock copolymers, where the block lengths of the terminal polymer blocks P(B) differ in linear systems, the content of polymer blocks P(B), at which the system still exhibits a spherical morphology, can be increased to above approximately 30 wt.%. This is particularly advantageous when an increase in the internal strength of the pressure-sensitive adhesive is required, as well as for improving its mechanical properties.

[0086] In one embodiment, the structure of at least one block copolymer BC, preferably several or all block copolymers BC, can be achieved by one or more of the following general

[0087] Formulas are described:

[0088] - P(A)-P(B)-P(A) (1a),

[0089] - P(B)-P(A)-P(B) (Ib),

[0090] - P(B)-P(A)-P(B)-P(A)-P(B) (Ha),

[0091] - P(A)-P(B)-P(A)-P(B)-P(A) (Hb), - [P(A)-P(B)]nX (Illa),

[0092] - [P(B)-P(A)]n X (lllb),

[0093] - [P(B)-P(A)-P(B)] n X (IVa),

[0094] - [P(A)-P(B)-P(A)] n X (IVb),

[0095] - [P(A)-P(B)] n X[P(B)] m (Va),

[0096] - [P(B)-P(A)] n X[P(A)] m (Vb), where n = 2 to 12, m = 1 to 12 and X represents a di- or multifunctional branching region.

[0097] The polymer blocks P(A), as described in the main claim or in advantageous embodiments, can be polymer chains of a single monomer type from monomers A or copolymers of monomers with different structures from monomers A. In particular, the monomers A used can vary in their chemical structure and / or side chain length. The polymer blocks thus encompass the range from completely homogeneous polymers to polymers of monomers with the same basic chemical structure but different chain lengths, and those with the same number of carbon atoms but different isomers, up to statistically polymerized blocks of monomers of different lengths and isomers from group A. The same applies to the polymer blocks P(B) with respect to the monomers from group B.

[0098] The unit P(A)-P(B)-P(A) can be symmetrical [corresponding to P 1 (A)-P(B)-P 2(A) with P 1 (A) = P 2 (A)] as well as asymmetrical [approximately according to formula P 3 (A)-P(B)-P 4 (A) with P 3 (A) P 4 (A), but both P 3 (A) as well as P 4 (A) each polymer blocks in the sense of the definition for P(A)] are constructed.

[0099] An advantageous embodiment is when at least one block copolymer, preferably several or all block copolymers, have a symmetrical structure such that polymer blocks P(A) and / or polymer blocks P(B) are identical in chain length and / or chemical structure. 3 (A) and P 4 (A) may differ in particular in their chemical composition and / or chain length.

[0100] In a preferred embodiment, at least one block copolymer BC, preferably several or all block copolymers BC, has at least one, particularly preferably two terminal groups P(B).

[0101] For an advantageous further development according to the invention, adhesive resins can be added to the block copolymer-containing pressure-sensitive adhesives. In principle, all resins soluble in the corresponding polymer block P(A) can be used. Suitable adhesive resins include, among others, rosin and rosin derivatives (rosin esters, also rosin derivatives stabilized by, for example, disproportionation or hydrogenation), polyterpene resins, terpene phenolic resins, alkylphenolic resins, aliphatic, aromatic, and aliphatic-aromatic hydrocarbon resins, to name just a few. Resins that are preferably compatible with polymer block (A) are preferred. The weight fraction of the resins in the block copolymer is typically up to 40 wt.%, more preferably up to 30 wt.%. For a specific embodiment of the invention, resins that are compatible with polymer block P(B) can also be used.

[0102] Optionally, plasticizers, fillers (e.g., fibers, carbon black, zinc oxide, titanium dioxide, chalk, solid or hollow glass spheres, microspheres made of other materials, silicic acid, silicates), nucleating agents, blowing agents, compounding agents and / or anti-aging agents, e.g., in the form of primary and secondary antioxidants or in the form of light stabilizers, may also be added.

[0103] Preferably, the internal strength (cohesion) of the pressure-sensitive adhesive is generated by the physical cross-linking of the polymer blocks P(B). The resulting physical cross-linking is typically thermoreversible. For non-reversible cross-linking, the pressure-sensitive adhesives can be additionally chemically cross-linked. For this purpose, the acrylate block copolymer-containing pressure-sensitive adhesives can optionally contain compatible cross-linking agents. Suitable cross-linking agents include, for example, metal chelates, multifunctional isocyanates, multifunctional amines, or multifunctional alcohols. Multifunctional acrylates can also be advantageously used as cross-linking agents for actinic irradiation.

[0104] In a further embodiment of the pressure-sensitive adhesive compound designed according to the invention, polymer blocks P(A) and / or P(B) are functionalized such that thermally initiated crosslinking can be carried out. Suitable crosslinkers include, among others, epoxides, aziridines, isocyanates, polycarbodiimides, and metal chelates, to name just a few.

[0105] For optional crosslinking with UV light, UV-absorbing photoinitiators are added to the polyacrylate-containing block copolymers used in the systems according to the invention. Useful photoinitiators that are very suitable for use include benzoin ethers, such as benzoin methyl ether and benzoin isopropyl ether; substituted acetophenones, such as 2,2-diethoxyacetophenone (available as Irgacure 651® from Ciba Geigy®), 2,2-dimethoxy-2-phenyl-1-phenylethanone, dimethoxyhydroxyacetophenone; substituted α-ketols, such as 2-methoxy-2-hydroxypropiophenone; aromatic sulfonyl chlorides, such as 2-naphthyl sulfonyl chloride; and photoactive oximes, such as... B. 1-Phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime. In an alternative embodiment, the pressure-sensitive adhesive composition according to the invention does not contain a crosslinker.

[0106] In a preferred embodiment, the adhesive compound according to the invention has an adhesive strength on steel, which is determined according to method 5, of at least 3 N / cm.

[0107] In a preferred embodiment, the adhesive compound according to the invention has a SAFT value, which is determined according to method 7, of at least 120 °C, preferably at least 140 °C.

[0108] In a preferred embodiment, the adhesive compound according to the invention has a shear life at room temperature, which is determined according to method 4, of at least 10,000 minutes.

[0109] In a particularly preferred embodiment, the adhesive compound according to the invention has a shear life at 70°C, which is determined according to method 4, of at least 2500 minutes, preferably at least 5000 minutes, and particularly preferably at least 10000 minutes.

[0110] In a particularly preferred embodiment, the adhesive compound according to the invention has a shear life at 120°C, which is determined according to method 4, of at least 750 minutes, preferably at least 1500 minutes, particularly preferably at least 5000 minutes, and most preferably at least 10,000 minutes.

[0111] Particularly preferred embodiments of the adhesive compounds according to the invention have an adhesion strength on steel, determined according to method 5, of at least 3 N / cm; a SAFT value, determined according to method 7, of at least 120 °C, preferably at least 140 °C; a shear life at room temperature, determined according to method 4, of at least 10,000 minutes; and a shear life at 70 °C, determined according to method 4, of at least 2,500 minutes, preferably at least 5,000 minutes, and particularly preferably at least 10,000 minutes.

[0112] A further object of the invention is a method for producing an adhesive bond according to the invention based on at least one block copolymer BC, characterized in that at least one polymerization step takes place in a closed shell and / or at least one polymerization step is a RAFT polymerization. In principle, all controlled or living polymerizations can be used to produce the block copolymers BC for the adhesive bond according to the invention, as well as combinations of different controlled polymerization processes. Examples, without claiming to be exhaustive, include anionic polymerization, ATRP, nitroxide / TEMPO-controlled polymerization, or, more preferably, the RAFT process—that is, in particular, processes that allow control of the block lengths, polymer architecture, or, but not necessarily, the tacticity of the polymer chain.

[0113] In one embodiment, the block copolymer BC is produced in two polymerization steps, the first polymerization step being carried out in the presence of a RAFT regulator.

[0114] The process for producing the at least one block copolymer BC comprises the following steps: a) the polymerization of a polymer block from monomers A to polymer block P(A) or from monomers B to polymer block P(B); and b) the polymerization of another polymer block from monomers A to polymer block (A) or from monomers B to polymer block (B) to the polymer block from step a) to form a block copolymer existing in at least two phases; wherein the monomers A and the monomers B are each used in one of the polymerization steps a) or b), and preferably a RAFT regulator is used in step a). In a further development, at least one polymerization step takes place in a closed shell.

[0115] In a preferred embodiment of the process for producing the at least one block copolymer BC, a polymer block is first polymerized from monomers A to polymer block P(A) in step a), and subsequently another polymer block is polymerized from monomers B to polymer block (B) in step b). In this preferred embodiment, it is particularly preferred that the monomers B1 are ACMO.

[0116] The RAFT polymerization of step a) can, in principle, be carried out in any manner. For example, it can be carried out in solvents, in particular in solvents in a conventional reactor designed for such polymerizations.

[0117] The RAFT polymerization of step b) can also be carried out in any manner. For example, it can be carried out in solvent, in particular in solvent in a conventional reactor designed for such polymerizations. In one embodiment, the polymerization of step a) takes place in a reactor, in particular in a reactor designed for processing highly viscous masses, or in a closed shell; more preferably, it takes place in a planetary mixer or in a closed shell.

[0118] The polymerization of step a) is also preferably carried out in the absence of solvent. Minimal solvent concentrations, e.g., resulting from production residues or at the level of ubiquitous solvents, are considered negligible.

[0119] "RAFT polymerization" stands for "reversible addition-fragmentation chain transfer polymerization." This refers to a polymerization process in which the reaction is controlled by reversible chain transfer reactions. In this process, an active, growing radical chain adds to a specific regulatory substance, the so-called RAFT agent, which is already bound to another chain and thus exists as a higher molecular weight RAFT agent (macro-RAFT agent). The addition of the active radical chain creates an intermediate that, due to its structure, can fragment in various directions. This process generates another macro-RAFT agent and an active radical chain available for propagation, the latter of which does not necessarily correspond to the previous active radical chain. In this way, the propagation probability is evenly distributed across all chains, typically resulting in a narrow molecular weight distribution.

[0120] In a preferred embodiment of this process, the polymerization of step a) and step b) is a controlled radical polymerization, particularly preferably a RAFT polymerization.

[0121] In accordance with the above, at least one of the polymerization steps, preferably all polymerization steps, is carried out in the presence of at least one regulator substance containing at least one sequence -SC(=X)-, wherein X represents S, O or NR', where R' represents an organic residue.

[0122] The regulator substance containing at least one sequence -SC(=X)- is preferably selected from the group consisting of

[0123] Dithioesters, i.e. compounds of the general structure (1 )

[0124] (1) ); Dithiocarbonates, i.e. compounds of the general structure (2)

[0125] Xanthates, compounds of the general structure (3)

[0126] (3);

[0127] Dithiocarbamates, compounds of the general structure (4)

[0128] Trithiocarbonates, i.e. compounds of the general structure (5)

[0129] (5); and

[0130] Imido-dithio carbonates, i.e. compounds of the general structure (6) wherein in the general structures (1) to (6) the substituents R each independently represent an organic or inorganic, preferably an organic, residue. In particular, at least one substituent R in the general structures (1) to (6) comprises a polymer chain formed during the polymerization in the relevant step. The regulator substance is particularly preferably comprising at least one sequence -SC(=X)- selected from trithiocarbonates and xanthates; in the above sense, therefore, preferably from compounds according to the general structures (3) and (5).

[0131] Particularly preferred is the regulator compound containing at least one sequence -S- C(X)- in its original state, i.e., without encompassed growing polymer chains, selected from the group consisting of dibenzyltrithiocarbonate, O-ethyl-S-(1-methyloxycarbonyl)ethylxanthate, 1,4-phenylenebis(methylene)didodecyltricarbonotrithioate, 2,2'-[carbonothioylbis(thio)]bis[2-methylpropanoic acid] and 4-cyano-4-

[0132] (((dodecylthio)carbonothioyl)thio)pentanoic acid.

[0133] For advantageous further development according to the invention, initiator systems can also be used in the manufacturing process, in particular thermally decomposing radical-forming azo or peroxide initiators. In principle, however, all conventional initiators known for acrylates are suitable for this purpose. The production of C-centered radicals is described in Houben-Weyl, Methods of Organic Chemistry, Vol. E19a, pp. 60ff. These methods are preferably used. Examples of radical sources are peroxides, hydroperoxides, and azo compounds. Some non-exclusive examples of typical radical initiators are: potassium peroxodisulfate, dibenzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, cyclohexylsulfonylacetyl peroxide, di-tert-butyl peroxide, azodiisobutyronitrile, diisopropyl percarbonate, tert-butyl peroctoate, and benzpinacol.In a highly preferred embodiment, 1,1'-azo-bis-(cyclohexylnitrile) (Vazo 88®, DuPont®) or 2,2-azo-bis-(2-methylbutanitrile) (Vazo 67®, DuPont®) is used as the radical initiator. Photoinitiators can also be used as radical sources. A "photoinitiator" is defined as a substance that forms radical species under the influence of light of certain wavelengths, usually at least under the influence of UV radiation, and optionally also under UV radiation in the wavelength range of visible light (approximately 300–500 nm). The photoinitiator forming at least one radical is preferably selected from the group consisting of 1-hydroxycyclohexylphenyl ketone and 2,2-dimethoxy-2-acetophenone.

[0134] To produce an adhesive, in particular a pressure-sensitive adhesive, in an extrusion process, the polymer system according to the invention, which optionally exists in a closed shell, is heated in the extruder to a temperature at which the shell material melts and can thus be homogeneously incorporated into the polymer system. As has been shown, the influence of the shell material on the properties of the adhesives produced with the polymer system according to the invention is below the threshold of technical relevance. The polymer system is heated to such an extent that it is deformable, in particular flowable. As has been found, the special polymer systems of the present invention often exhibit lower viscosities and thus better deformability and flowability than conventional polymers used, in particular, for the production of pressure-sensitive adhesives.The polymer system according to the invention can thus be processed into an adhesive mass in an extruder under the influence of heat and shear, optionally also with the incorporation of further components, and finally shaped. The temperatures typically used in this process do not lead to the decomposition of the regulatory substances incorporated into the polymer backbones and therefore also not to polymer degradation. A significant advantage of the invention is that no solvent removal is required before processing the polymer systems in the extruder, a process that regularly leads to the degradation processes just described.

[0135] Further processing steps, such as mixing with additives, filtration, or degassing, can also take place in the extruder. The resulting adhesive, particularly pressure-sensitive adhesive, can then be formed into a desired layer shape, for example, using a calender onto a substrate or release liner. During the processing of the polymer system into an adhesive, especially a pressure-sensitive adhesive, the polymer system can be mixed with other components. These additional components can be selected from the following groups: other polymers; adhesive-enhancing resins; fillers, such as electrically conductive fillers, thermally conductive fillers, and the like; flame retardants, such as ammonium polyphosphate and its derivatives; foaming agents; antioxidants; light stabilizers; plasticizers; and compounding particles.

[0136] The adhesive compound according to the invention can be used as such, e.g., in the form of a layer or a carrier-free layer of the adhesive compound according to the invention, which is also referred to as "transfer tape". Such a transfer tape is preferably applied only to a material that temporarily serves to protect the adhesive surface, to facilitate handling, and to make the adhesive compound easier to apply. Such materials are also referred to as release liners or simply as "liners" and are generally easily removable, particularly by means of suitable surface coatings. The second side of the transfer tape can also be provided with a liner.

[0137] Release liners are carrier materials that are coated or treated with an anti-adhesive finish on one or, preferably, both sides. Suitable carrier materials for release liners include various papers, optionally in combination with a stabilizing extrusion coating. Other suitable liner carrier materials are films, especially polyolefin films, for example, based on ethylene, propylene, butylene, and / or hexylene. Preferred carrier materials are papers, such as glassine papers. Papers are preferred, not least because the concept of using components derived from renewable raw materials can thus be extended to the adhesive tape's auxiliary materials.

[0138] Silicone systems are frequently used as anti-adhesive release liners. Commonly used liners include, for example, siliconized papers and siliconized films.

[0139] For using the transfer tape to bond to a substrate surface, the liner(s) are removed, allowing both adhesive sides to make direct contact with the substrate surfaces to be bonded. The liner is therefore not a component in the tape itself and is not considered part of the tape; rather, it merely serves as an aid for handling the tape.

[0140] The adhesive compound according to the invention can also be used in the construction or production of multilayer adhesive tapes. Such multilayer adhesive tapes typically comprise at least one carrier layer and can have an outer layer of the adhesive compound according to the invention on one or both sides. In the case of double-sided adhesive tapes, either one or both outer layers can be adhesive compounds according to the invention. In the latter case, the adhesive layers can differ with respect to their chemical composition and / or their chemical and / or physical properties and / or their geometry (e.g., layer thickness); however, they are particularly preferably identical with respect to their chemical composition and / or their chemical and / or physical properties.Even with multi-layered adhesive tapes, one or both outer adhesive layers can be covered with liners.

[0141] The adhesive tapes may have additional layers, e.g., additional backing layers, functional layers, or the like.

[0142] Bio-based materials are preferably selected as backing materials for the multilayer adhesive tape, for example those selected from the list consisting of papers; bio-based fabrics or nonwovens, for example made of cotton or viscose; cellophane; cellulose acetate; bio-based polyethylene (PE) films and polypropylene (PP) films; TI

[0143] Films made of thermoplastic starch; bio-based polyester films, e.g., films made of polylactic acid (PLA), polyethylene terephthalate (PET), polyethylene tetrahydrofuranoate (PEF), or polyhydroxyalkanoate (PHA). A PET film is particularly preferred as the substrate. PET films are preferred, for example, because they can be used as a recycled material and thus meet sustainability requirements.

[0144] For the adhesion of the pressure-sensitive adhesive to the carrier or another substrate, it can be advantageous to treat the adhesive and / or the substrate with corona or plasma before coating. Furthermore, for the adhesion of the pressure-sensitive adhesive layer to subsequent layers, especially to a carrier layer, it can be advantageous to use chemical bonding, e.g., via a primer.

[0145] The adhesive products according to the invention find a wide variety of applications, for example in the construction industry, the electronics industry, the DIY sector, the automotive industry, shipbuilding, boatbuilding and railway construction, for household appliances, furniture and the like. Advantageous applications include, for example, the bonding of strips and emblems in the aforementioned areas, the bonding of stiffening profiles in elevators, the bonding of components and products in the solar industry, frame bonding in consumer electronics such as televisions and the like, and bonding in sign manufacturing.

[0146] Another aspect of the present invention relates to the use of the adhesive compound or adhesive tape according to the invention, comprising an adhesive compound according to the invention, for bonding in outdoor applications, in automobiles, in electronic, optical and / or precision mechanical devices.

[0147] The adhesive composition and adhesive tapes according to the invention are ideally suited for bonding flexible printing plates to curved surfaces. In flexographic printing, flexible printing plates (also known as clichés) are bonded to printing cylinders or printing tubes. Such clichés consist, for example, of a polyethylene terephthalate film (PET film) onto which a layer of a photopolymer is applied, into which the corresponding printing relief can be introduced by exposure to light. The cliché is then bonded to the printing cylinder or printing tube via the PET film. The adhesive tapes according to the invention excellently meet the very high requirements in this area.For the printing process, the adhesive tape must possess a certain degree of hardness as well as elasticity. Furthermore, the adhesive strength should be sufficient to prevent the printing plate from detaching from the double-sided adhesive tape, or vice versa. This is crucial, for example, even at elevated temperatures of 40 to 60 °C and at higher printing speeds. In addition to this property, the adhesive should also be reversible, allowing the printing plates to be removed after printing. (The adhesive bond between the tape and the printing cylinder or sleeve, as well as the bond to the printing plate, must be removable without leaving any residue to ensure the reusability of both components.) This removability should be maintained even after prolonged bonding (up to 6 months).Furthermore, it is desirable that the adhesive tape, and in particular the printing plate, can be removed without damage, i.e., without requiring significant force, since the printing plates are generally reused multiple times. Additionally, no residue should remain on the printing plate or on the cylinder or sleeve. In summary, very high demands are placed on the double-sided adhesive tapes suitable for this application, demands which are excellently met by the adhesive compound according to the invention.

[0148] The adhesive can be advantageously used to bond components of precision mechanical, optical, electrical, and / or electronic devices, for example, during their manufacture, repair, decoration, or similar applications. Materials such as plastics, glass, metals, and the like can be bonded using this method.

[0149] The adhesive is particularly suitable for the permanent bonding of flexible materials, especially in the production of flexible displays. Such displays are becoming increasingly important.

[0150] Advantageously, the adhesive can be used for bonding windows or lenses in the housings of precision mechanical, optical, and / or electronic devices (so-called "lens mounting"). At least one of the rigid or flexible substrates is transparent or translucent. The transparent or translucent substrate can, for example, be a window or an optical lens for the purpose of protecting sensitive components located beneath it—such components can be, for example, liquid crystal displays (LCDs), light-emitting diodes (LEDs), or organic light-emitting diodes (OLEDs) in displays, but also printed circuit boards or other sensitive electronic components; this plays a significant role, for example, in applications for touch-sensitive displays—and / or for producing optical effects for the device's function—for example, refraction, focusing, attenuation, amplification, etc.- be.

[0151] It is very advantageous to select the transparent substrate such that it has a haze value of at most 50%, preferably of no more than 10%, very preferably of no more than 5% (measured according to ASTM D 1003).

[0152] The second substrate is preferably also a component of a precision mechanical, optical and / or electronic device. In particular, this includes housings for such devices or mounts for windows or lenses as described above.

[0153] In a preferred procedure, the transparent or translucent substrate is a substrate made of glass, polymethyl methacrylate and / or polycarbonate.

[0154] In particular, the second substrate can consist of plastics such as acrylonitrile butadiene styrene copolymers (ABS), polyamide or polycarbonate, which can also be glass fiber reinforced; or of metals such as aluminum - including anodized aluminum - or magnesium and metal alloys.

[0155] Additives such as dyes, light stabilizers, anti-aging agents, plasticizers or the like may also be added to the substrate materials, provided this is advantageous for the intended purpose; in the case of transparent or translucent materials, in particular to the extent that it does not disturb these optical properties or only to an acceptable degree.

[0156] According to the invention, the composite is thus a component of an electronic, optical or precision mechanical device.

[0157] Electronic, optical and precision mechanical devices within the meaning of this application are, in particular, devices such as those classified in Class 9 of the International Classification of Goods and Services for the Purposes of the Registration of Marks (Nice Classification); 10th Edition (NCL(10-2013)); provided that they are electronic, optical or precision mechanical devices, and also watches and timekeeping devices in accordance with Class 14 (NCL(10-2013)), such as, in particular,

[0158] • Scientific, nautical, surveying, photographic, cinematographic, optical, weighing, measuring, signalling, checking (supervision), lifesaving and teaching apparatus and instruments; • Apparatus and instruments for conducting, switching, transforming, storing, regulating and controlling electricity;

[0159] • Image recording, processing, transmission and playback devices, such as televisions and the like

[0160] • Acoustic recording, processing, transmission and playback devices, such as radios and the like

[0161] • Computers, calculating and data processing equipment, mathematical devices and instruments, computer accessories, office equipment – ​​such as printers, fax machines, copiers, typewriters – data storage devices

[0162] • Remote communication and multifunctional devices with remote communication functionality, such as telephones, answering machines

[0163] • Chemical and physical measuring devices, control units and instruments, such as battery chargers, multimeters, lamps, tachometers

[0164] • Nautical equipment and instruments

[0165] • Optical devices and instruments

[0166] • Medical devices and instruments, and those for athletes

[0167] • Watches and chronometers

[0168] • Solar cell modules, such as electrochemical dye-sensitized solar cells, organic

[0169] Solar cells, thin-film cells,

[0170] • Fire extinguishers.

[0171] Technological developments are increasingly focused on devices that are becoming ever smaller and lighter, so that they can be carried by their owners at all times and are typically carried regularly. This is usually achieved by making such devices lightweight and / or appropriately sized. In this document, such devices are also referred to as mobile devices or portable devices. This development trend involves the increasing integration of electronic components into precision mechanical and optical devices, further increasing the possibilities for miniaturization. Because mobile devices are carried around, they are subjected to increased stress, particularly mechanical stress, such as from bumping against edges, being dropped, contact with other hard objects in a pocket, and even the constant movement inherent in carrying them.Mobile devices are also exposed to greater stresses due to moisture, temperature influences, and the like than "immobile" devices that are usually installed indoors and are not, or hardly, moved. The adhesive compound used according to the invention has proven to be particularly advantageous in withstanding such disturbances and, ideally, in mitigating or compensating for them.

[0172] Below are some examples of portable devices.

[0173] • Cameras, digital cameras, photography accessories (such as light meters, flash units, apertures, camera bodies, lenses, etc.), film cameras, video cameras

[0174] • Small computers (mobile computers, pocket computers, calculators), laptops, notebooks, netbooks, ultrabooks, tablet computers, handhelds, electronic calendars and organizers (so-called "Electronic Organizers" or "Personal Digital Assistants", PDAs, palmtops), modems,

[0175] • Computer accessories and control units for electronic devices, such as mice, drawing pads, graphics tablets, microphones, speakers, game consoles, gamepads, remote controls, remote controls, touchpads

[0176] • Monitors, displays, screens, touch-sensitive screens (sensor screens, "touchscreen devices"), projectors

[0177] • Reading devices for electronic books (“e-books”),

[0178] • Small television sets, pocket televisions, film players, video players

[0179] • Radios (including small and pocket radios), Walkmans, Disemons, music players for e.g. CD, DVD, Blu-ray, cassettes, USB, MP3, headphones

[0180] • Cordless phones, mobile phones, smartphones, two-way radios, hands-free devices, personal alarm devices (pagers, beepers)

[0181] • Mobile defibrillators, blood glucose meters, blood pressure monitors, pedometers, pulse monitors

[0182] • Flashlights, laser pointers

[0183] • Mobile detectors, optical magnifiers, long-range vision devices, night vision devices

[0184] • GPS devices, navigation devices, portable satellite communication interface devices

[0185] • Data storage devices (USB sticks, external hard drives, memory cards)

[0186] • Wristwatches, digital watches, pocket watches, chain watches, stopwatches. Examples

[0187] Measurement and testing methods:

[0188] Method 1 - Determination of the glass transition temperature of polymers

[0189] The static glass transition temperature of the polymers was determined using Dynamic Scanning Calorimetry (DSC). For this purpose, 5 mg of an untreated sample of the polymer in question was weighed into an aluminum crucible (volume 25 pl) and sealed with a perforated lid. A Netzsch DSC 204 F1 was used for the measurement. The sample was inerted under nitrogen. It was first cooled to -150 °C, then heated to +150 °C at a rate of 10 K / min and cooled again to -150 °C. The subsequent second heating cycle was also performed at 10 K / min, and the change in heat capacity was recorded. Glass transitions are identified as steps in the thermogram (heat-temperature diagram, see Figure 1).

[0190] The glass transition temperature T g is obtained as follows (see Figure 1):

[0191] The linear portions of the measurement curve before and after the step are extended in the direction of increasing (before the step) and decreasing (after the step) temperatures, respectively (extension lines © and ®). Within the step, a regression line ® is placed parallel to the ordinate such that it intersects the two extension lines, resulting in two areas ® and @ (between the extension line, the regression line, and the measurement curve, respectively) of equal area. The intersection of this regression line with the measurement curve yields the glass transition temperature.

[0192] Method 2 - Determination of molar masses

[0193] The values ​​for weight-average molar mass M wThis document refers to the well-known determination method by gel permeation chromatography (GPC). The determination is performed on 100 µL of clear-filtered sample (sample concentration 3 g / L). Tetrahydrofuran is used as the eluent. The measurement is carried out at 25 °C.

[0194] A PSS-SDV type column, 5 pm, 10 is used as the upstream column. 3 Ä, 8.0 mm * 50 mm (Specifications here and below in the order: type, particle size, inner diameter * length; 1 Ä = 10 -1 ° m) is used. For separation, a combination of columns of type PSS SDV, 5 pm, 10 is used. 3 Ä and 10 5 A and 10 6 Columns measuring 8.0 mm x 300 mm each were used (Agilent columns; detection via PSS SECcurity differential refractometer). 2The flow rate is 1.0 ml per minute. Calibration is performed using the commercially available Agilent ReadyCal kit for poly(styrene) high. This is universally converted to polymethyl methacrylate (PMMA) using the Mark-Houwink parameters K and alpha, so that the data is given in PMMA mass equivalents.

[0195] 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 The following components were used: 104 and 106, each with an ID of 8.0 mm x 300 mm. The sample concentration is 4 g / l, and the flow rate is 1.0 ml per minute. Calibration is performed using the commercially available ReadyCal kit for polystyrene high from PSS Polymer Standard Service GmbH, Mainz, Germany.

[0196] Polydispersity (PDI) is determined, as is known to those skilled in the art, as the quotient of weight-average and number-average molar mass.

[0197] Method 3 - Dynamic-Mechanical Analysis (DMA)

[0198] G' and G" are determined using a rheometer. The material under investigation is subjected to a sinusoidally oscillating shear stress in a plate-plate arrangement. In shear-stress controlled instruments, the deformation is measured as a function of time, along with the time lag of this deformation relative to the application of the shear stress. This time lag is referred to as the phase angle θ.

[0199] The storage modulus G' is defined as follows: G' = (T / y) * cos(θ) (T = shear stress, y = deformation, θ = phase angle = phase shift between shear stress and deformation vectors). The definition of the loss modulus G" is: G" = (T / y) * sin(θ) (T = shear stress, y = deformation, θ = phase angle = phase shift between shear stress and deformation vectors). tan θ = G7G'.

[0200] Instrument: MCR 302e rheometer (Anton Paar), plate-to-plate, Ø 12 mm

[0201] Deformation: Dynamic adaptation

[0202] Measurement frequency: 1 Hz

[0203] Measurement method: Frequency Sweep

[0204] Measuring range: 10 5 — 10 2 Hz Method 4 - Determination of static shear strength (shear life; SSZ)

[0205] Shear strength is a measure of the internal strength of the adhesive and was tested in the so-called static shear test as follows:

[0206] The test was performed under standard climate conditions (23 °C, 50% relative humidity; SLS (RT) 1 kg) using a 1 kg weight. A 1.3 cm wide strip of the sample (50 µm polymer layer on 36 µm etched PET film) was bonded to a polished steel plate over a length of 2 cm by rolling it with a 2 kg roller (twice in each direction). The plates were equilibrated for 30 min under test conditions but without a load. Then the test weight (1 kg) was attached, creating a shear stress parallel to the bonded area, and the time until bond failure was measured. The measurement result is given in minutes. The median of three individual measurements is reported. A shear life at room temperature of at least 10,000 min is considered a good result.

[0207] The shear life is determined under a test climate of 70 ± 1 °C and 10% ± 10% relative humidity (“SSZ (70°C) 0.5 kg”) analogously to the procedures described above, whereby the prepared plate was equilibrated for 30 minutes under the test conditions at 70 °C before a 0.5 kg weight was suspended. A shear life at 70 °C of at least 2500 minutes is considered good for temperature stability, at least 5000 minutes very good, and at least 10000 minutes exceptionally good.

[0208] The shear life is determined under a test climate of 120 ± 1 °C and 10% ± 10% relative humidity (“SSZ (120°C) 0.25 kg”) analogously to the procedures described above, whereby the prepared plate is equilibrated for 30 minutes under the test conditions at 120 °C before a 0.25 kg weight is suspended. A shear life of at least 750 minutes at 120 °C is considered a good result for temperature stability. A shear life of at least 1500 minutes at 120 °C is considered a very good result for temperature stability, and at least 5000 minutes or even at least 10,000 minutes is considered an exceptionally good result.

[0209] Method 5 - Adhesive strength of steel

[0210] The adhesive strength was determined under a test climate of 23 °C ± 1 °C and 50% ± 5% relative humidity. The samples were cut to a width of 20 mm and adhered to a steel plate (ASTM). The steel plate was cleaned and conditioned before adhesion. For this, the plate was first wiped with solvent and then left to air dry for 5 minutes to allow the solvent to evaporate. The side of the adhesive tape facing away from the test substrate was then covered with 25 g / m² etched PET film, preventing the sample from stretching during measurement. The test sample was then rolled onto the substrate. For this, the tape was rolled back and forth five times with a 4 kg roller at a winding speed of 10 m / min. One minute after rolling, the plate was inserted into a special holder.The adhesive strength was measured using a Zwick tensile testing machine; the samples were peeled off at an angle of 180° at a speed of 300 mm / min. The measurement results are given in N / cm and are averaged from three individual measurements. An adhesive strength of at least 3 N / cm is considered a good result.

[0211] Method 6 - Determination of the Tack

[0212] In this test, a 5.6 g steel ball rolled from a 65 mm high ramp (21° incline) onto a horizontal strip of the adhesive being tested. The distance the ball traveled until it came to a stop was measured (test climate 23°C, 50% relative humidity). A distance of up to 300 mm is considered a good result.

[0213] The spheres were cleaned with cellulose and acetone before measurement and conditioned in the test climate for 30 minutes.

[0214] The adhesive was conditioned in the test climate for one day before measurement.

[0215] Method 7 - Determination of the Shear Adhesion Failure Temperature (SAFT)

[0216] The SAFT determination was carried out as follows: A polished steel surface was used as the defined bonding surface. The bondable surface element to be tested was cut to a width of 10 mm and a length of approximately 5 cm and immediately thereafter pressed three times onto the selected bonding surface (10 x 13 mm area) using a 2 kg steel roller at a feed rate of 10 m / min. Immediately afterwards, the previously bonded surface element was loaded with 0.5 N at an angle of 180° and a temperature ramp of 9°C / min was applied. The temperature at which the sample traveled a sliding distance of 1 mm was measured. The measured value (in °C) is the average of two individual measurements. A SAFT value above 120 °C is considered a good result, and a SAFT value above 140 °C is considered a very good result. Production of Polymer A

[0217] A conventional 3 L vessel for radical polymerizations was filled with 900 g of n-butyl acrylate (nBA), 3.933 g of 1,4-phenylenebis(methylene)didodecyl dicarbonotrithioate (BM1812; CAS 960256-58-0), and 900 g of ethyl acetate (EtAc). After passing nitrogen gas through the reactor for 45 minutes while stirring, the contents were heated to 58°C and 0.229 g of Vazo® 67 were added. The reactor contents were then heated further to 65°C. After a reaction time of 24 hours, the reactor contents were cooled to 35°C. The conversion was >95%, and the proportion of polymer A in the polymer solution was 50 wt%.

[0218] The polymer A has a weight-average molar mass M w of 238,000 g / mol and a polydispersity PDI of 1.46.

[0219] Production of polymer B

[0220] A conventional 3 L vessel for radical polymerizations was filled with 427.5 g of 2-ethylhexyl acrylate, 427.5 g of n-butyl acrylate, 45 g of acrylic acid, and 3.51 g of 1,4-phenylenebis(methylene)didodecyl dicarbonotrithioate (BM1812; CAS 960256-58-0), as well as 900 g of ethyl acetate (EtAc). After passing nitrogen gas through the vessel for 45 minutes while stirring, the reactor contents were heated to 58°C and 0.20 g of Vazo® 67 was added. The reactor contents were then heated further to 65°C. After a reaction time of 24 hours, the reactor contents were cooled to 35°C. The conversion was >95% and the proportion of polymer A in the polymer solution was 50 wt%.

[0221] Polymer B has a weight-average molar mass M w of 481,000 g / mol and a polydispersity PDI of 2.6.

[0222] Production of the block copolymer BC1

[0223] A conventional 3 L vessel for radical polymerizations was filled with 1467 g of the polymer solution of polymer A and 166.5 g of 4-acryloylmorpholine (ACMO; CAS: 51 17-12-4) as well as 166.5 g of ethanol (EtOH). After passing nitrogen gas through the vessel for 45 minutes with stirring, the reactor contents were heated to 58°C and 0.187 g of Vazo® 67 were added. The reactor contents were then heated further to 65°C. After 3 h, the mixture was diluted with 300 g of ethyl acetate:ethanol (1:1) and again after 5 h with 300 g of ethyl acetate:ethanol (1:1). After a reaction time of 24 h, the reactor contents were cooled to 35°C. The conversion was >97%.

[0224] The block copolymer BC1 has a weight average molar mass M w of 337,000 g / mol and a polydispersity PDI of 5.1. Preparation of the block copolymer BC2

[0225] A conventional 3 L vessel for radical polymerizations was filled with 1350 g of the polymer solution of polymer B, 225 g of 4-acryloylmorpholine (ACMO; CAS: 51 17-12-4), and 225 g of ethanol (EtOH). After passing nitrogen gas through the vessel for 45 minutes while stirring, the reactor contents were heated to 58°C, and 0.154 g of Vazo® 67 was added. The reactor contents were then heated further to 65°C. After 3 h, the mixture was diluted with 300 g of ethyl acetate:ethanol (1:1), and again after 5 h with 300 g of the same dilution. After a reaction time of 24 h, the reactor contents were cooled to 35°C. The conversion was >97%.

[0226] The block copolymer BC2 has a weight-average molar mass M w of 295,000 g / mol and a polydispersity PDI of 4.5.

[0227] Production of the block copolymer BC3

[0228] A conventional 3 L vessel for radical polymerizations was filled with 1350 g of the polymer solution of polymer A, 225 g of N-tert-butylacrylamide (NTBAM), and 153 g of ethyl acetate (EtAc). After 45 minutes of nitrogen gas purging with stirring, the reactor contents were heated to 58°C and 0.172 g of Vazo® 67 was added. The reactor contents were then heated further to 65°C. After 3 h, the mixture was diluted with 300 g of ethyl acetate, and again after 5 h with another 300 g of ethyl acetate. After a reaction time of 24 h, the reactor contents were cooled to 35°C. The conversion was >97%.

[0229] The block copolymer BC3 has a weight-average molar mass M w of 377,000 g / mol and a polydispersity PDI of 3.7.

[0230] Production of the block copolymer BC4

[0231] A conventional 3 L vessel for radical polymerizations was filled with 1521 g of the polymer solution of polymer A, 139.5 g of N-isopropylacrylamide (NIPAM), and 139.5 g of ethyl acetate (EtAc). After passing nitrogen gas through the reactor for 45 minutes with stirring, the contents were heated to 58°C and 0.194 g of Vazo® 67 were added. The reactor contents were then heated further to 65°C. After 3 h, the mixture was diluted with 300 g of ethyl acetate, and again after 5 h with 300 g of ethyl acetate. After a reaction time of 24 h, the reactor contents were cooled to 35°C. The conversion was >97%. The block copolymer BC4 has a weight-average molar mass M w of 382,000 g / mol and a polydispersity PDI of 3.6.

[0232] Production of comparative example 2 - Statistical copolymer

[0233] A conventional 3 L vessel for radical polymerizations was filled with 733.5 g of n-butyl acrylate (nBA), 166.5 g of 4-acryloylmorpholine (ACMO; CAS 5117-12-4), 3,206 g of 1,4-phenylenebis(methylene)didodecyl dicarbonotrithioate (BM1812; CAS 960256-58-0), and 900 g of ethyl acetate (EtAc). After 45 minutes of nitrogen gas purging with stirring, the reactor contents were heated to 58°C and 0.180 g of Vazo® 67 was added. The reactor contents were then heated further to 65°C. After 3 h, the mixture was diluted with 300 g of ethyl acetate, and again after 5 h with another 300 g of ethyl acetate. After a 24-hour reaction time, the reactor contents are cooled to 35°C. The conversion rate is >97%.

[0234] Comparative example 2 has a weight-average molar mass M w of 177,000 g / mol and a polydispersity PDI of 3.0.

[0235] Sample preparation for measurement and testing methods

[0236] Unless otherwise specified, the prepared block copolymers were coated from solution onto a siliconized release film (50 µm polyester) using a doctor blade and subsequently dried (coating speed 2.5 m / min, drying tunnel 15 m, temperatures Zone 1: 40 °C, Zone 2: 70 °C, Zone 3: 95 °C, Zone 4: 105 °C). The mass deposition after drying was 50 g / m². 2 .

[0237] Table 1: Adhesive strength, SAFT and shear life of the block copolymers aV = adhesive failure; nb = not determined;

[0238] The commercially available LA2330 (Kuraray Co., LTD.; Comparative Example 1) is an n-butyl acrylate-based block copolymer which has a PMMA content of approximately 20 wt.%.

[0239] For examples BC1 and BC4, the shear life at 120 °C [SSZ (120°C), 0.25 kg] was determined. BC1 exhibits a shear life at 120 °C [SSZ (120°C), 0.25 kg] of > 10,000 min. BC4 exhibits a shear life at 120 °C [SSZ (120°C), 0.25 kg] of 870 min.

[0240] The examples according to the invention exhibit good adhesive strength in combination with good shear strength, especially at elevated temperatures.

Claims

Patent claims 1. Pressure-sensitive adhesive based on at least one block copolymer BC comprising at least one polymer block P(A) and at least one polymer block P(B), wherein P(A) independently comprising homo- or copolymer blocks comprising a total of at least 80 wt.% monomers A selected from the group consisting of methacrylic esters, methacrylamides and monomers with at least one polymerizable vinyl group; P(B) independently comprising homo- or copolymer blocks comprising a total of at least 80 wt.% monomers B selected from the group consisting of methacrylic acid esters, methacrylamides and monomers with at least one polymerizable vinyl group; characterized in that the monomers A comprise a total of at least 50 wt.% one or more acrylate monomers A1 selected from the general structure CH2=CH-C(O)OR 1 include; where R 1Each occurrence is independently selected from a linear or branched alkyl group with 4 to 17 carbon atoms; - the monomers B comprising at least 60 wt% in total one or more (meth)acrylamide monomers B1 selected from the general structure CH2=CR 2 -C(O)NR 3 R 4 include; whereby R 2 The selection for each occurrence is independently of each other from H and CH3; R 3 In each occurrence, it is independently selected from the group consisting of alkyl groups, hydroxyalkyl groups, thioalkyl groups, and acetonyl groups; and R 4 selected independently at each occurrence from the group consisting of hydrogen, alkyl groups, hydroxyalkyl groups, aryl groups, aminoalkyl groups and acetonyl groups; or R 3 and R 4 together they form an organic chain of compounds, such that NR 3 R 4a ring with n ring atoms, where n is in the range of 5 to 8.

2. Adhesive compound according to claim 1, characterized in that the monomers B1 are selected from the general structure CH2=CR 2 -C(O)NR 3 R 4 include; where R 2 equal to H or CH3, preferably R 2 equal to H; R 3 in each occurrence is independently selected from alkyl groups, preferably with 1 to 10 carbon atoms, particularly preferably with 1 to 6 carbon atoms; and R 4 selected from the group consisting of hydrogen and alkyl groups, preferably with 1 to 10 carbon atoms, particularly preferably with 1 to 6 carbon atoms; or R 3 and R 4 together they form an organic chain of compounds, such that NR 3 R 4 a six-membered ring which optionally contains oxygen or sulfur as one of the 6 ring atoms.

3. Adhesive compound according to one of the preceding claims, characterized in that R 2 is equal to H; R 3 Each occurrence is independently selected from alkyl groups with 1 to 4 carbon atoms; and R 4 selected from the group consisting of hydrogen and alkyl groups with 1 to 4 carbon atoms; or R 3 and R 4 together they form an organic chain of compounds, such that the monomers B1 have a structure according to formula B1-1: Formula B1 -1 where X is selected from the group consisting of O, S and CH2.

4. Pressure-sensitive adhesive according to one of the preceding claims, characterized in that the monomers B1 are selected from the group consisting of dimethylacrylamide, N-iso-propylacrylamide, Nt-butylacrylamide, 4-acryloylmorpholine and N-(3-(Dimethylamino)propyl)acrylamide, preferably from the group consisting of 4-acryloylmorpholine, N-iso-propylacrylamide, Nt-butylacrylamide.

5. Adhesive compound according to one of the preceding claims, characterized in that the monomers B1 each have a glass transition temperature of the homopolymer in question which is greater than or equal to 90°C, preferably greater than or equal to 100°C, in particular greater than or equal to 105°C, and most preferably greater than 120°C.

6. Adhesive compound according to one of the preceding claims, characterized in that the monomers A1 each have a glass transition temperature of the homopolymer in question which is less than or equal to 0 °C, more preferably less than or equal to -10 °C, and in particular preferably less than or equal to -20 °C.

7. Pressure-sensitive adhesive according to one of the preceding claims, characterized in that the block copolymer BC has a weight-average molar mass M w > 200,000 g / mol, preferably M w > 350,000 g / mol, especially preferred M w > 500,000 g / mol.

8. Pressure-sensitive adhesive according to one of the preceding claims, characterized in that the block copolymer BC has a polydispersity greater than 2.

9. Adhesive compound according to one of the preceding claims, characterized in that the polymer blocks P(B) are present in a proportion between 5 and 49 wt.%; preferably between 7.5 and 35 wt.%; in particular between 10 and 30 wt.%, most preferably between 12 and 28 wt.%; based on the totality of the polymer blocks P(A) and P(B) of the block copolymer BC.

10. Adhesive compound according to one of the preceding claims, characterized in that the at least one polymer block P(B) has a glass transition temperature of > 50 °C, more preferably of > 70 °C, in particular of > 90 °C.

11. Adhesive compound according to one of the preceding claims, characterized in that the at least one polymer block P(A) has a glass transition temperature of < 0 °C, more preferably of < -10 °C, in particular of < -20 °C.

12. Pressure-sensitive adhesive according to one of the preceding claims, characterized in that the block copolymer BC can be described by one or more of the following general formulas: P(A)-P(B)-P(A) (1a) P(B)-P(A)-P(B) (lb) P(B)-P(A)-P(B)-P(A)-P(B) (Ha) P(A)-P(B)-P(A)-P(B)-P(A) (Hb) [P(A)-P(B)]nX (Illa) [P(B)-P(A)]nX (Hlb) [P(B)-P(A)-P(B)]nX (IVa) [P(A)-P(B)-P(A)] n X (IVb) [P(A)-P(B)] n X[P(B)] m (Va) [P(B)-P(A)]nX[P(A)] m (Vb) where n = 2 to 12, m = 1 to 12 and X represents a di- or multifunctional branching region.

13. Adhesive compound according to one of the preceding claims, characterized in that the polymer blocks P(A) and P(B) are not homogeneously miscible with each other.

14. Pressure-sensitive adhesive according to one of the preceding claims, characterized in that the monomers A1 are selected from the group consisting of n-butyl acrylate, iso-butyl acrylate, iso-amyl acrylate, n-hexyl acrylate, n-heptyl acrylate, 2-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, iso-octyl acrylate, n-nonyl acrylate, iso-nonyl acrylate, 2-propylheptyl acrylate, n-decyl acrylate, iso-decyl acrylate, lauryl acrylate, tetradecyl acrylates, heptadecyl acrylate.

15. Adhesive compound according to one of the preceding claims, characterized in that the monomers A and monomers B comprise a total of a maximum of 15 wt.%, preferably a total of a maximum of 10 wt.%, particularly preferably a total of a maximum of 5 wt.% methyl methacrylate.

16. Adhesive compound according to one of the preceding claims, characterized in that the monomers A and / or monomers B are substantially free of methyl methacrylate; more preferably free of methacrylic acid esters and methacrylamides; in particular free of any methacrylic compounds.

17. Adhesive compound according to one of the preceding claims, comprising at least one block polymer BC to at least 50 wt.%, preferably to at least 60 wt.%, particularly preferably to 70 wt.% based on the total weight of the adhesive compound.

18. Adhesive tape comprising an adhesive compound according to any one of claims 1 to 17.

19. A method for producing an adhesive compound according to one of claims 1 to 17, characterized in that at least one polymerization step takes place in a closed shell and / or is a RAFT polymerization.

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