Method for producing a multi-phase polymer system

Abstract

The invention relates to a method for producing polymers on the basis of monomers with functionalised vinyl groups, by means of which polymers with a controlled architecture and tight molecular weight distribution can be produced such that in the event of subsequent thermal load, their mechanical properties are largely maintained. This is achieved by a method for producing a polymer system available in at least two phases, comprising the following steps: a) RAFT polymerisation of a monomer composition I comprising in total at least 80 wt.% of one or more monomers selected from the group consisting of methacrylic esters, methacrylamides and monomers with at least one polymerisable vinyl group to form a polymerisate A; and b) RAFT polymerisation of a monomer composition II comprising in total at least 80 wt.% of one or more monomers selected from the group consisting of methacrylic esters, methacrylamides and monomers with at least one polymerisable vinyl group, wherein the monomer composition II differs in at least 50 wt.% of its monomers from the monomer composition I, in the presence of polymerisate A to form a polymerisate B, thereby obtaining a polymer system, available in at least two phases, comprising the polymerisate A and B; characterised in that the RAFT polymerisations of steps a) and b) are carried out independently of one another in the presence of a specifically structured RAFT controller substance.

Description

[0001] Process for producing a multiphase polymer system

[0002] The present invention lies in the technical field of polymerization processes, which are used in a wide variety of ways, both with regard to the equipment used and the process conditions, for the targeted production of plastics with specific property profiles. More specifically, the invention proposes a process for producing a multiphase polymer system comprising at least two-stage RAFT polymerization, each of which is carried out in the presence of a specific RAFT regulator substance. The most important application background for the multiphase polymer systems produced in this way is pressure-sensitive adhesives for adhesive tapes, which are used to generate both temporary and permanent material bonds in various fields of technology.

[0003] For industrial adhesive tape applications, polymers based on the polymerization of monomers with functionalized vinyl groups are often used. A well-known example of such polymers is poly(meth)acrylate. Poly(meth)acrylates offer several advantages over other plastics used as a basis for adhesive applications. For example, they are highly stable against high-energy radiation and oxidizing substances. In contrast to poly(meth)acrylates, synthetic rubbers and natural rubbers often contain carbon-carbon double bonds, which make these polymers, and thus also adhesive components based on them, vulnerable to UV radiation, oxygen, and ozone, for example. Furthermore, poly(meth)acrylate-based plastic formulations can be transparent and can be used over a wide temperature range.

[0004] An important aspect that influences the properties of polymers based on monomers with functionalized vinyl groups is the polymer architecture. In the distant past, work was mostly carried out with statistical copolymers, in which the monomers were randomly distributed throughout the polymer chain. In recent decades, polymers with controlled structures, such as block copolymers or copolymers with a monomer distribution gradient, have come into focus. Attempts are therefore being made to specifically control the property profile of the polymers and the plastic formulations based on them through the distribution or arrangement of the monomers. In this way, it is possible to achieve essentially contradictory properties with one and the same polymer base. In this context, so-called RAFT polymerization has proven to be a highly suitable method.

[0005] "RAFT polymerization" stands for "reversible addition-fragmentation chain transfer polymerization." This refers to a polymerization in which reaction control is achieved through reversible chain transfer reactions. An active, growing radical chain adds to a special regulator, the so-called RAFT agent, which is already linked 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 whose structure allows it to fragment in various directions. This process again produces a macro-RAFT agent and an active radical chain available for propagation, although the latter does not necessarily have to correspond to the previously active radical chain. In this way, the propagation probability is evenly distributed across all chains, resulting in a narrow molecular weight distribution.

[0006] Methods for the controlled polymerization of (meth)acrylates are described in the prior art.

[0007] WO 2004 / 101627 A1 describes a process for the continuous polymerization of acrylic monomers to polyacrylates in the presence of polymerization-regulating substances, wherein at least one polymerization step is carried out within at least one reaction extruder.

[0008] WO 2013 / 072120 A1 relates to a process for producing acrylate-based polymers, in which a controlled radical polymerization reaction of a reaction mixture comprising at least one acrylate-based monomer is first carried out in the presence of at least one regulator substance having at least one functional group SC=X, where X = S, O or N, wherein the regulator substance is selected from the group comprising dithioesters, dithiocarbonates, dithiocarbamates, trithiocarbonates, imidodithiocarbonates and xanthates (“RAFT regulators”), wherein the majority of the regulator substance molecules are incorporated into the resulting polymer chains, after which the respective polymer chain has the functional group of the incorporated regulator, characterized in that at least one chemical compound having at least two conjugated double bonds (hereinafter referred to as “conjugated diene”) is brought into contact with the polymers thus obtained,so that hetero-Diels-Alder reactions are effected between the double bonds C=X of the functional groups SC=X incorporated into the polymer chains and the conjugated double bonds of the conjugated diene.

[0009] EP 2 607 394 A1 discloses a process for producing pressure-sensitive adhesives, in which a controlled radical polymerization reaction of a reaction mixture comprising one or more monomers is carried out in the presence of at least one radical initiator to produce at least one polymer, characterized in that at least one cyclic 1,4-diradical is used as the radical initiator, which is produced by means of a cyclization reaction from a compound having at least two unsaturated CC bonds ("diradical-forming compound"), wherein the polymerization reaction is carried out in the presence of at least one regulator substance ("polymerization regulator").

[0010] WO 2013 / 055978 A1 describes acrylic copolymers that feature a controlled placement of specific functional groups within the polymer structure. The copolymers contain at least two reactive segments and are produced via a controlled radical polymerization process. The copolymers are useful in the production of adhesives and elastomers.

[0011] WO 2018 / 118905 A1 describes a crosslinkable composition comprising a) a polymeric material of the formula wherein

[0012] Ri is hydrogen, alkyl, fluorinated alkyl, aryl, aralkyl or substituted aralkyl;

[0013] X is oxygen or -NR2, wherein R2 is hydrogen, alkyl, fluorinated alkyl, aryl, aralkyl or substituted aryl; each R3 is alkoxy, fluorinated alkoxy or -N(R4)2, wherein each R4 is alkyl or fluorinated alkyl or together with the nitrogen to which they are both attached form a heterocyclic ring; each P is a polymeric block comprising a polymerized product of a first monomer composition comprising at least one monomer having a single ethylenically unsaturated group; y is an integer from 1 to 5; and b) a second monomer composition miscible with the polymeric material of the formula and comprising a crosslinking monomer having at least two ethylenically unsaturated groups.

[0014] WO 2018 / 178829 A1 describes controlled radical initiators, reaction mixtures containing them and various ethylenically unsaturated monomers; polymeric materials formed from these reaction mixtures; crosslinkable compositions containing the polymeric materials, and crosslinked compositions formed from them. The controlled radical initiators are bis-dithiocarbamate and bis-dithiocarbonate compounds with a single carbon atom between the two dithiocarbamate or dithiocarbonate groups.

[0015] In the past, polymers based on monomers with functionalized vinyl groups were regularly produced from solution and, naturally, further processed in this form, for example, into (pressure-sensitive) adhesives. The polymers, optionally blended with other substances, are coated from solution onto a carrier material using a coating bar or similar tool and then dried. To increase cohesion, the polymers are usually crosslinked, which is usually achieved either thermally, by UV radiation, or by electron beams. The solvent process is economically inefficient overall and environmentally harmful, as the solvents are either not recovered and then pollute the environment, or must be recovered at a high energy expenditure.

[0016] In addition, quality issues also regularly arise. For example, adhesive tapes with higher mass application based on the polymers described are often difficult to produce without bubbles.

[0017] To mitigate these disadvantages, attempts have been made to apply the polymers, or the compositions produced with them, from the melt to the carrier material in a so-called hotmelt process during the production of adhesive tapes. However, this technique also has limitations. It is in the nature of a hotmelt process that the polymers are exposed to high temperatures during processing from the melt. If certain RAFT regulators, such as symmetrically substituted trithiocarbonates, are used to produce the polymers in RAFT polymerization, the resulting polymers contain a central trithiocarbonate group. This group is thermally labile and can therefore decompose during the hotmelt process. Such decomposition processes manifest themselves in polymer degradation and, in the case of adhesives, for example, in a measurable loss of cohesion.

[0018] WO 98 / 01478 A1 relates to a free radical polymerization process which comprises contacting:

[0019] (i) a monomer selected from the group consisting of vinyl monomers, maleic anhydride, N-alkylmaleimide, N-arylmaleimide, dialkyl fumarate and cyclopolymerizable monomers;

[0020] (ii) a thiocarbonylthio compound having a chain transfer constant greater than 0.1; and

[0021] (iii) free radicals from an appropriate source, and adjusting the polydispersity of the polymer by varying the number of molecules (ii) to the number of molecules (iii). In this context, thiocarbonylthio compounds are proposed that lead to polymers that are subject to degradation upon thermal stress and thus suffer from a loss of cohesion.

[0022] EP 1 312 658 A2 describes pressure-sensitive adhesive systems, at least comprising a pressure-sensitive adhesive based on at least one block copolymer, wherein the weight fractions of the block copolymers in total make up at least 50% of the pressure-sensitive adhesive, wherein at least one block copolymer is composed at least partly on the basis of (meth-)acrylic acid derivatives, wherein furthermore at least one block copolymer has at least the unit P(A)-P(B)-P(A) of at least one polymer block P(B) and at least two polymer blocks P(A), and wherein

[0023] - P(A) independently represent homo- or copolymer blocks of monomers A, wherein the polymer blocks P(A) each have a softening temperature in the range from + 20 °C to + 175 °C,

[0024] - P(B) represents a homo- or copolymer block of monomers B, wherein the polymer block P(B) has a softening temperature in the range from -130 °C to + 10 °C,

[0025] - the polymer blocks P(A) and P(B) are not homogeneously miscible with one another, characterized in that the pressure-sensitive adhesive system is oriented in that it has a preferred direction, wherein the refractive index nMD measured in the preferred direction is greater than the refractive index Ncd measured in a direction perpendicular to the preferred direction. The pressure-sensitive adhesives are coated from the melt. This document also describes regulator substances that appear to be critical with regard to polymer degradation due to thermal stress.

[0026] It was an object of the invention to avoid the problems known from the prior art and to provide a process for the production of polymers based on monomers with functionalized vinyl groups, with which polymers with controlled architecture and narrow molecular weight distribution can be produced in such a way that their mechanical properties are largely retained upon subsequent thermal stress.

[0027] It was a further object of the invention to offer such a process that offers high flexibility for changes in the polymer formulation and the desired polymer architecture.

[0028] A supplementary object of the invention was to provide polymers that can be produced in this way and have good cohesion and good melt processability.

[0029] In particular, it was an object of the invention to provide polymers based on monomers with functionalized vinyl groups with controlled architecture and narrow molecular weight distribution, which survive coating onto a carrier material from the melt without significant loss of cohesion.

[0030] It was a further additional object of the invention to provide such polymers which are particularly suitable for adhesive tape applications.

[0031] A first and general subject matter of the invention, with which these objects are achieved, is a process for producing a polymer system present in at least two phases, comprising the steps of: a) RAFT polymerization of a monomer composition I comprising a total of at least 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides and monomers having at least one polymerizable vinyl group to form a polymer A; and b) RAFT polymerization of a monomer composition II comprising a total of at least 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides and monomers having at least one polymerizable vinyl group, wherein the monomer composition II consists of at least 50% by weight of-% of its monomers differs from those of the monomer composition I, in the presence of the polymer A to a polymer B to obtain a polymer system present in at least two phases comprising the polymers A and B; characterized in that the RAFT polymerizations of steps a) and b) are carried out independently of one another in the presence of a RAFT regulator substance which, in its original state, has the general structure (I).

[0032] R'-C(=S)-SR (I) or the general structure (II)

[0033] R'-C(=S)-SR"-SC(=S)-R' (II), wherein the substituents R' independently of one another represent an aryl, aralkyl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio, alkoxy, alkaryloxy or alkenoxy radical or a radical (NR 1 )2, in which the substituents R 1independently of one another represent an alkyl or aryl radical or form with the N atom a heterocyclic ring having 1 to 3 heteroatoms, independently of one another selected from the group consisting of N, O and S;

[0034] R represents a sec- or tert-alkyl radical, a cyano-sec-alkyl radical, a cyano-tert-alkyl radical, a carboxy-tert-alkyl radical, a carboxy-sec-alkyl radical, an aralkyl radical or a radical of the general structure (III)

[0035] -CR 2 R 3 R 4 (III), wherein R 2 represents an alkyl radical or H, R 3 represents a cyano, carboxy or carboxylic acid ester group and R 4 represent an aryl radical; and

[0036] R" for a group of the general structure (IV)

[0037] -CR 5 R 6 -Y-CR 5 R 6 - (IV) where R 5 and R 6independently of one another represent a hydrogen atom, an n-alkyl group, a cyano group, a carboxy group or a carboxylic acid ester group and

[0038] Y represents an alkylene or arylene group or a group having a structure selected from -(CH2)m-CO-O-(CH2)nO-CO-(CH2)m- and -(CH2)m-CO-NR 7 -(CH2)n-NR 7 -CO-(CH2)m-, where n is an integer from 1 to 12, m is 0 to 4 and R 7 represents an organyl radical; stands;

[0039] As has been shown, multiphase polymer systems can be produced from solution in this way, which even survive the necessary removal of the solvent, which is regularly associated with particularly high temperatures, without any significant loss of cohesion and can then be further processed from the melt largely without any problems.

[0040] Details and embodiments of the invention are described below. Those embodiments that are designated as preferred in any form below are combined in particularly preferred embodiments with features of other embodiments that are designated as preferred in any form below. Combinations of two or more of the embodiments that are designated as particularly preferred in any form below are thus very particularly preferred. Likewise preferred are embodiments in which a feature of one embodiment that is designated as preferred to any extent is combined with one or more further features of other embodiments that are designated as preferred to any extent.

[0041] To the extent that both specific amounts or proportions of an element and preferred embodiments of the element are disclosed below, the specific amounts or proportions of the preferably configured elements are also disclosed. Furthermore, it is disclosed that, with the corresponding specific total amounts or total proportions of the elements, at least some of the elements can be preferably configured, and in particular, that preferably configured elements can in turn be present in the specific amounts or proportions within the specific total amounts or total proportions.

[0042] 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 expert's understanding, a "polymer" or "a single polymer" is understood not only to refer to a single macromolecule, but also to a multitude of macromolecules that originate from one and the same polymerization process and have a specific molecular weight distribution among themselves.

[0043] The polymer system resulting from the process according to the invention exists in at least two phases. A person skilled in the art understands this to mean that one phase is rich in one component of the polymer system, for example polymer A, or consists essentially of this component, and the other phase is rich in another component, for example polymer B, or consists essentially of this component. The presence of small amounts of one component in the other, which does not preclude the formation of multiphases, is considered irrelevant. If the polymer system resulting from the process according to the invention has more than two phases, the above applies accordingly to all of these phases.

[0044] The phase separation is particularly preferably realized in such a way that discrete regions (“domains”) which are rich in polymer A or polymer B - i.e. are essentially formed from polymer A or polymer B - are present in a continuous matrix which is rich in the respective other polymer - i.e. is essentially formed from the respective other polymer.

[0045] A polymer system resulting from the process 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 can be identified in a height profile analysis of an atomic force microscopy (AFM) image of the polymer system. b) At least two independent glass transition temperatures are obtained from a dynamic differential scanning calorimetry (DSC) measurement carried out on the polymer system. c) At least two tan δ maxima are obtained from a dynamic mechanical analysis (DMA) carried out on the polymer system.

[0046] According to the invention, the polymer system present in at least two phases also comprises a microphase-separated polymer system, i.e. a polymer system in which the discontinuous phase is present in microscopically fine distribution.

[0047] The process according to the invention comprises a step a) in which the RAFT polymerization of a monomer composition I which comprises at least 80% by weight, based on the total weight of the monomer composition I, one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides and monomers having at least one polymerizable vinyl group, takes place to form a polymer A. The monomer composition I preferably comprises at least 85% by weight, more preferably at least 90% by weight, particularly preferably at least 95% by weight, in particular at least 98% by weight, of one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides and monomers having at least one polymerizable vinyl group.Most preferably, the monomer composition I comprises exclusively one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides and monomers having at least one polymerizable vinyl group.

[0048] The RAFT polymerization of step a) can, in principle, be carried out in any desired manner. It is preferably carried out in solvent, in particular in a conventional reactor designed for such polymerizations.

[0049] The polymer A resulting from the polymerization of step a) is preferably a polymer block from which or to which at least one further, distinguishable polymer block can be polymerized.

[0050] The process according to the invention comprises a step b) in which, in the presence of the polymer A, the RAFT polymerization of a monomer composition II which comprises at least 80% by weight, based on the total weight of the monomer composition I, one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides and monomers having at least one polymerizable vinyl group, wherein the monomer composition II differs from those of the monomer composition I in at least 50% by weight of its monomers, to a polymer B to obtain a polymer system comprising the polymers A and B which is present in at least two phases.

[0051] The monomer composition II preferably comprises one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides, and monomers having at least one polymerizable vinyl group to an extent of at least 85% by weight, more preferably at least 90% by weight, particularly preferably at least 95% by weight, in particular at least 98% by weight. Most preferably, the monomer composition II exclusively comprises one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides, and monomers having at least one polymerizable vinyl group.

[0052] The RAFT polymerization of step b) can also, in principle, be carried out in any desired manner. It is preferably carried out in solvent, in particular in a conventional reactor designed for such polymerizations.

[0053] The radical formation and thus the polymerization in step a) is preferably initiated by radiation, particularly preferably by UV radiation. In step b), the radical formation and thus the polymerization is also preferably initiated by radiation, particularly preferably by UV radiation.

[0054] A preferred subject of the invention is thus a process for producing a polymer system present in at least two phases, comprising the steps: a) UV-initiated RAFT polymerization of a monomer composition I comprising a total of at least 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters,

[0055] Methacrylamides and monomers having at least one polymerizable vinyl group to form a polymer A; and b) UV-initiated RAFT polymerization of a monomer composition II comprising at least 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters,

[0056] Methacrylamides and monomers having at least one polymerizable vinyl group, wherein the monomer composition II differs in at least 50% by weight of its monomers from those of the monomer composition I, in the presence of the polymer A to a polymer B to obtain a polymer system present in at least two phases comprising the polymers A and B; characterized in that the RAFT polymerizations of steps a) and b) are carried out independently of one another in the presence of a RAFT regulator substance which, in its original state, has the general structure (I)

[0057] R'-C(=S)-SR (I) or the general structure (II) R'-C(=S)-SR"-SC(=S)-R' (II), wherein the substituents R' independently of one another represent an aryl, aralkyl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio, alkoxy, alkaryloxy or alkenoxy radical or a radical (NR 1 )2, in which the substituents R 1 independently of one another represent an alkyl or aryl radical or form with the N atom a heterocyclic ring having 1 to 3 heteroatoms, independently of one another selected from the group consisting of N, O and S;

[0058] R represents a sec- or tert-alkyl radical, a cyano-sec-alkyl radical, a cyano-tert-alkyl radical, a carboxy-tert-alkyl radical, a carboxy-sec-alkyl radical, an aralkyl radical or a radical of the general structure (III)

[0059] -CR 2 R 3 R 4 (III), wherein R 2 represents an alkyl radical or H, R 3represents a cyano, carboxy or carboxylic acid ester group and R 4 represent an aryl radical; and

[0060] R" for a group of the general structure (IV)

[0061] -CR 5 R 6 -Y-CR 5 R 6 - (IV) where R 5 and R 6 independently of one another represent a hydrogen atom, an n-alkyl group, a cyano group, a carboxy group or a carboxylic acid ester group and

[0062] Y represents an alkylene or arylene group or a group having a structure selected from -(CH2)m-CO-O-(CH2)nO-CO-(CH2)m- and -(CH2)m-CO-NR 7 -(CH2)n-NR 7 -CO-(CH2)m-, where n is an integer from 1 to 12, m is 0 to 4 and R 7 represents an organyl radical; stands;

[0063] The process according to the invention is intended to result in a polymer system consisting of at least two phases. Another aim of the invention was to provide the two- or multi-phase polymer system with the highest possible cohesion. Therefore, it seemed important to consider these and, if necessary, other properties of the final polymer system when selecting the monomers used in the two polymerization steps.

[0064] Against this background, in one embodiment of the invention, one of the monomer compositions I and II comprises 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. % of one or more monomers having a glass transition temperature of the homopolymer in question of <0 °C, more preferably of <-10 °C, in particular of <-20 °C; and the respective other of the monomer compositions I and II comprises 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. % of one or more monomers having a glass transition temperature of the homopolymer in question of >50 °C, more preferably of >75 °C, in particular of >100 °C.

[0065] In a continuation of this embodiment, one of the monomer compositions I and II preferably comprises at least 50% by weight in total, more preferably at least 60% by weight in total, in particular at least 75% by weight in total, of one or more monomers selected from the group consisting of ethyl acrylate, n-butyl acrylate, isobutyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-heptyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, isooctyl acrylate, n-nonyl acrylate, isononyl acrylate, n-decyl acrylate, isodecyl 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; and the other of the monomer compositions I and II comprises a total of at least 60 wt.%, more preferably a total of at least 70 wt.%,insbesondere zu insgesamt mindestens 80 Gew.-% ein oder mehrere Monomere ausgewählt aus der Gruppe bestehend aus Isobornylacrylat, Norbornylacrylat, Benzylacrylat, 3,3,5- T rimethylcyclohexylacrylat, Cyclohexylacrylat, 4-[(6-Acryloyloxy)hexyloxy]4‘-cyanobiphenyl, N-Succinimidylacrylat, 1 -Ethylcyclopentylacrylat, N-tert-Octylacrylamid, N-tert-Butylacrylamid, Dimethylacrylamid, Diethylacrylamid, N-iso-Propylacrylamid, Acrylamid, N-[3- (Dimethylamino)propyl]acrylamid, Diacetonacrylamid, N-(Butoxymethyl)acrylamid, N- Phenylacrylamid, N-[2-(Dimethylamino)ethyl]acrylamid, N-[2-(Diethylamino)ethyl]acrylamid, Methylmethacrylat, Ethylmethacrylat, Cyclohexylmethacrylat, Benzylmethacrylat, Isobornylmethacrylat, Glycerolformalmethacrylat, 2-Dimethylaminoethylmethacrylat, Phenoxyethylmethacrylat, 9-Anthrylmethylmethacrylat, 2-Ethyl-2-adamantylmethacrylat, 2- (Acetoacetyloxy)ethylmethacrylat, 2-lsopropyl-2-methacryloyloxyadamantan, iso- Propylmethacrylat, iso-Butylmethacrylat,tert-Butylmethacrylat, Furfurylmethacrylat, 2- Methacryloyloxy-2-methyladamantan, 2-Morpholinoethylmethacrylat, Phenylmethacrylat, N- Succinimidylmethacrylat, 2-(tert-Butylamino)ethylmethacrylat, 2-Cyclohexylpropan-2-yl- methacrylat, 1 -Adamantylmethacrylat, 1 -Methylcyclopentylmethacrylat, 3- Dimethylaminopropylmethacrylamid, N-tert-Butylmethacrylamid, N-,

[0066] (Methoxymethyl)methacrylamid, N,N-Dimethylmethacrylamid, Methacrylamid, N- Phenylmethacrylamid, N,N-Dimethylmethacrylamid, N-iso-Propylmethacrylamid, N- Vinylformamid, N-Vinylpyrrolidon, N-Vinylcaprolactam, N-Vinylcrbazol, N-Vinylimidazol, Vinylmethyloxazolidinon und N-Vinyl-N-methylacetamid.

[0067] More preferably, one of the monomer compositions I and II comprises a total of at least 50% by weight, more preferably a total of at least 60% by weight, in particular a total of at least 75% by weight of 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, n-decyl acrylate and iso-decyl acrylate; and the respective other of the monomer compositions I and II comprises 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.% of one or more monomers selected from the group consisting of isobornyl acrylate, norbornyl acrylate, tert-butyl methacrylate, benzyl acrylate, N-isopropylacrylamide, N-tert-octylacrylamide, N-tert-butylacrylamide and dimethylacrylamide.

[0068] In a further development of this embodiment, one of the monomer compositions I and II preferably comprises a total of at least 50% by weight, more preferably a total of at least 60% by weight, in particular a total of at least 75% by weight of one or more monomers selected from the group consisting of ethyl acrylate, 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, n-decyl acrylate, iso-decyl acrylate, 2-

[0069] [[(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; to a total of not more than 35 wt.%, more preferably to a total of not more than 25 wt.%, in particular to a total of not more than 20 wt.% of one or more monomers selected from the group consisting of isobornyl acrylate, norbornyl acrylate, methyl methacrylate, dimethylacrylamide, diethylacrylamide, 4-tert-butylcyclohexyl acrylate, tert-butyl acrylate, tert-butyl methacrylate, cyclohexyl methacrylate and cyclohexyl acrylate and to a total of not more than 10 wt.% of one or more functionalized monomers; and the respective other of the monomer compositions I and II comprises 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.% of one or more monomers selected from the group consisting of isobornyl acrylate, norbornyl acrylate,Benzylacrylat, 3,3,5- T rimethylcyclohexylacrylat, Cyclohexylacrylat, 4-[(6-Acryloyloxy)hexyloxy]4‘-cyanobiphenyl, N-Succinimidylacrylat, 1 -Ethylcyclopentylacrylat, N-tert-Octylacrylamid, N-tert-Butylacrylamid, Dimethylacrylamid, Diethylacrylamid, N-iso-Propylacrylamid, N-Hydroxyethylacrylamid, Acrylamid, N-[3-(Dimethylamino)propyl]acrylamid, Diacetonacrylamid, N- (Butoxymethyl)acrylamid, N-Phenylacrylamid, N-[2-(Dimethylamino)ethyl]acrylamid, N-[2- (Diethylamino)ethyl]acrylamid, Methylmethacrylat, Ethylmethacrylat, Cyclohexylmethacrylat, Benzylmethacrylat, Isobornylmethacrylat, Glycerolformalmethacrylat, 2- Dimethylaminoethylmethacrylat, , Phenoxyethylmethacrylat, 9-Anthrylmethylmethacrylat, 2- Ethyl-2-adamantylmethacrylat, 2-(Acetoacetyloxy)ethylmethacrylat, 2-lsopropyl-2- methacryloyloxyadamantan, iso-Propylmethacrylat, iso-Butylmethacrylat, tert- Butylmethacrylat, Furfurylmethacrylat, 2-Methacryloyloxy-2-methyladamantan, 2- Morpholinoethylmethacrylat, Phenylmethacrylat,N-succinimidyl methacrylate, 2-(tert-butylaminoethyl methacrylate, 2-cyclohexylpropan-2-yl methacrylate, 1-adamantyl methacrylate, 1-methylcyclopentyl methacrylate, 3-dimethylaminopropyl methacrylamide, N-tert-butyl methacrylamide, N-(methoxymethyl)methacrylamide, N,N-dimethylmethacrylamide, N-phenyl methacrylamide, N,N-dimethylmethacrylamide, N-isopropyl methacrylamide, N-vinylformamide, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylcrbazole, N-vinylimidazole, vinylmethyloxazolidinone and N-vinyl-N-methylacetamide; and up to a total of not more than 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, 4-hydroxyethyl acrylamide, acrylic acid, methacrylic acid, 2-acryloxyethyl succinate, methacryloxyethyl succinate,Sulfoethylmethacrylat, Acrylamid, Methacrylamid, Glycidylacrylat, Glycidylmethacrylat, 3,4- Epoxycyclohexylmethylacrylat, 3,4-Epoxycyclohexylmethylmethacrylat, 4- Hydroxybutylacrylateglycidylether, 4-Hydroxybutylmethacrylateglycidylether,

[0070] Isocyanatoethylacrylat, Isocyanatoethylmethacrylat, 2-[2-

[0071] (Methacryloyloxy)ethyloxy]ethylisocyanat, 2-[2-(Acryloyloxy)ethyloxy]ethylisocyanat und a, a - Dimethyl-m-lsopropenylbenzylisocyanat.

[0072] In particular, one of the monomer compositions I and II comprises a total of at least 50% by weight, more preferably a total of at least 60% by weight, in particular a total of at least 75% by weight of 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, n-decyl acrylate and isodecyl acrylate; a total of not more than 35% by weight, more preferably a total of not more than 25% by weight, in particular a total of not more than 20% by weight of one or more monomers selected from the group consisting of isobornyl acrylate, norbornyl acrylate, methyl methacrylate, dimethylacrylamide and a total of not more than 10% by weight.-% of 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-epoxycyclohexyl methyl methacrylate, glycidyl acrylate and glycidyl methacrylate; and the respective other of the monomer compositions I and II comprises 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.% of one or more monomers selected from the group consisting of isobornyl acrylate, norbornyl acrylate, tert-butyl methacrylate, benzyl acrylate, N-isopropylacrylamide, N-tert-octylacrylamide, N-tert-butylacrylamide and dimethylacrylamide; and a total of not more than 10 wt.-% of 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-epoxycyclohexyl methyl methacrylate, glycidyl acrylate, and glycidyl methacrylate. In a specific embodiment of the process according to the invention, at least the monomer composition II is free of methyl methacrylate; more preferably, it is free of methacrylic acid esters and methacrylamides; in particular, it is free of any methacrylic compounds.

[0073] Preferably, the monomer composition I is also free from methyl methacrylate; more preferably, it is free from methacrylic acid esters and methacrylamides; in particular, it is free from any methacrylic compounds.

[0074] As has been shown, the exclusion of the above-mentioned compounds has a beneficial effect on the polymerization rate.

[0075] According to the invention, the polymerizations of steps a) and b) take place independently of each other in the presence of a special RAFT regulator substance which, in its original state, corresponds to the general structure (I)

[0076] R'-C(=S)-SR (I) or the general structure (II)

[0077] R'-C(=S)-SR"-SC(=S)-R' (II). "In its original state" here means that the regulator substance in question is considered without any component resulting from the monomers used in the polymer chain linked to it from the beginning of polymerization.

[0078] The substituents R' in the general structures (I) and (II) independently of one another preferably represent an aryl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio or alkoxy radical or a radical (NR 1 )2, wherein the substituents R 1 independently of one another represent an aryl radical. More preferably, the n-alkyl groups contained in the substituents mentioned are Cs-C2o-n-alkyl groups, especially C-Cis-n-alkyl groups; and the aryl groups are phenyl groups.

[0079] Y in the general structure (IV) preferably represents an alkylene or arylene group, more preferably an arylene group, and particularly preferably a phenylene group. A further preferred subject of the invention is a process for producing a polymer system present in at least two phases, comprising the steps: a) UV-initiated RAFT polymerization of a monomer composition I comprising, to a total of at least 80% by weight, one or more monomers selected from the group consisting of methacrylic acid esters,

[0080] Methacrylamides and monomers having at least one polymerizable vinyl group to form a polymer A; and b) UV-initiated RAFT polymerization of a monomer composition II comprising at least 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters,

[0081] Methacrylamides and monomers having at least one polymerizable vinyl group, wherein the monomer composition II differs in at least 50% by weight of its monomers from those of the monomer composition I, in the presence of the polymer A to a polymer B to obtain a polymer system present in at least two phases comprising the polymers A and B; characterized in that the RAFT polymerizations of steps a) and b) are carried out independently of one another in the presence of a RAFT regulator substance which, in its original state, has the general structure (I)

[0082] R'-C(=S)-SR (I) or the general structure (II)

[0083] R'-C(=S)-SR”-SC(=S)-R' (II), wherein the substituents R' independently of one another represent an aryl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio or alkoxy radical or a radical (NR 1 )2, wherein the substituents R 1independently represent an aryl residue;

[0084] R represents a sec- or tert-alkyl radical, a cyano-sec-alkyl radical, a cyano-tert-alkyl radical, a carboxy-tert-alkyl radical, a carboxy-sec-alkyl radical, an aralkyl radical or a radical of the general structure (III)

[0085] -CR 2 R 3 R 4 (III), wherein R 2 represents an alkyl radical or H, R 3 represents a cyano, carboxy or carboxylic acid ester group and R 4 represent an aryl radical; and

[0086] R" for a group of the general structure (IV)

[0087] -CR 5 R 6 -Y-CR 5 R 6 - (IV) where R 5 and R 6 independently of one another represent a hydrogen atom, an n-alkyl group, a cyano group, a carboxy group or a carboxylic acid ester group and

[0088] Y stands for an arylene group;

[0089] In one embodiment of the invention, the RAFT regulator substance in its original state corresponds to the general structure (I), R' stands for an aryl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio or alkoxy radical or a radical (NR 1 )2, wherein the substituents R 1 independently of one another represent an aryl radical; the n-alkyl groups are preferably Cs-C2o-n-alkyl groups, in particular C-Cis-n-alkyl groups, the aryl groups are preferably phenyl groups; and R represents a cyano-tert-alkyl radical, a carboxy-tert-alkyl radical or a benzylthio radical.

[0090] In a further embodiment, the RAFT regulator substance in its original state corresponds to the general structure (II), in which the substituents R' are identical. Preferably, the substituents R' each represent an aryl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio or alkoxy radical or a radical (NR 1 )2, in which the substituents R 1 independently of one another represent an aryl radical. More preferably, the n-alkyl groups contained in the substituents mentioned are Cs-C2o-n-alkyl groups, in particular Cw-Cis-n-alkyl groups; and the aryl groups are phenyl groups. Independently of or in combination with the preferred substituents described so far herein, in this embodiment, R" represents a group of the general structure (V)

[0091] -CH2-Y-CH2- (V).

[0092] Y preferably represents an arylene group and particularly preferably a phenylene group. In one embodiment of the process according to the invention, at least the RAFT polymerization of step b) is carried out in a solvent, and the process comprises c) removing the solvent under the influence of heat.

[0093] A significant advantage of the process according to the invention is that the polymers produced in steps a) and b) can undergo this step without significant loss of cohesion, regardless of the apparatus used for solvent removal. Preferably, the solvent removal takes place in an extruder.

[0094] The invention further provides a polymer system present in at least two phases, which can be prepared by a process according to the invention. Preferably, the polymer system obtainable by a process according to the invention is a block copolymer. The polymer blocks of this block copolymer are preferably formed by polymers A and B. More preferably, the polymer system obtainable by a process according to the invention is a triblock copolymer, in particular a triblock copolymer of the form ABA or BAB, where A and B represent polymers A and B.

[0095] Polymer systems according to the invention are characterized, among other things, by the fact that they withstand the effects of high temperatures, such as those used in particular for the removal of solvents in concentration extruders and similar devices, but also during further processing, for example, by extrusion, without significant loss of cohesion. Without wishing to be bound to this theory, the inventors assume that the selection of the RAFT regulator substances used in the process according to the invention ensures that the RAFT regulators are not located within the polymer chains at the end of the polymerization, but rather at the terminals. Since the RAFT regulators are the most thermally labile structures within the polymer systems, their decomposition under thermal stress does not lead to polymer degradation and the associated loss of cohesion, as would be expected if the RAFT regulator structures were located within the chains.Due to their cohesive strength, polymer systems according to the invention can preferably be used as a component of a pressure-sensitive adhesive produced by thermally mechanically induced mixing of its underlying components, as occurs, for example, in an extruder. The invention thus further provides for the use of a polymer system according to the invention as a component for producing a pressure-sensitive adhesive by a process comprising thermally mechanically induced mixing of the components for producing the pressure-sensitive adhesive.

[0096] According to expert understanding, a pressure-sensitive adhesive is an adhesive that possesses pressure-sensitive adhesive properties, i.e., the ability to form a permanent bond to a substrate even under relatively light pressure. Such adhesives or pressure-sensitive adhesive 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 under light pressure. Without wishing to be bound by this theory, it is often assumed that a pressure-sensitive adhesive can be considered an extremely viscous liquid with an elastic component, which consequently possesses characteristic viscoelastic properties that lead to the permanent tackiness and pressure-sensitive adhesive capacity described above.It is assumed that mechanical deformation of pressure-sensitive adhesives results in both viscous flow processes and the buildup of elastic restoring forces. The partial viscous flow serves to achieve adhesion, while the partial elastic restoring forces are particularly necessary to achieve cohesion. The relationships between rheology and pressure-sensitive tack are well known in the art and are described, for example, in "Satas, Handbook of Pressure Sensitive Adhesives Technology", Third Edition, (1999), pages 153 to 203. To characterize the degree of elastic and viscous components, the storage modulus (G') and the loss modulus (G") are usually used; these can be determined by means of dynamic mechanical analysis (DMA), for example using a rheometer.In the context of the present invention, an adhesive is preferably understood as pressure-sensitive adhesive and thus as a pressure-sensitive adhesive if, at a temperature of 23 °C in the deformation frequency range from 10° to 10. 1 rad / sec G' and G“ each at least partly in the range of 10 3 up to 10 7 Pa lie.

[0097] The equipment used to produce the pressure-sensitive adhesive, which could be an extruder, for example, can also include additional process steps such as mixing with additives, filtration, or degassing. The resulting pressure-sensitive adhesive can be formed into a desired layer, for example, using a calender on a carrier or release liner.

[0098] During the processing of a polymer system according to the invention into a pressure-sensitive adhesive, the polymer system can be mixed with further components. These further components can be selected from the group consisting of further polymers; adhesive strength-enhancing resins; fillers, for example electrically conductive fillers, thermally conductive fillers, and the like; flame retardants, for example ammonium polyphosphate and its derivatives; foaming agents; ageing inhibitors; light stabilizers; plasticizers, and compounding particles.

[0099] Examples

[0100] Measurement and testing methods:

[0101] Method 1 - Determination of the glass transition temperature of polymers

[0102] 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 DSC 204 F1 from Netzsch was used for the measurement. The measurement was carried out under nitrogen for inerting. The sample was first cooled to -150 °C, then heated at a heating rate of 10 K / min to +150 °C and cooled again to -150 °C. The subsequent second heating curve was again run at 10 K / min and the change in heat capacity was recorded. Glass transitions are detected as steps in the thermogram (heat flow-temperature diagram, see Figure 1).

[0103] The glass transition temperature T g is obtained as follows (see Figure 1 ):

[0104] The linear sections of the measurement curve before and after the step are extended in the direction of increasing (area before the step) or decreasing (area after the step) temperatures (extension lines © and ®). In the step region, a best-fit line ® is placed parallel to the ordinate so that it intersects the two extension lines, creating two areas ® and @ (between the extension line, the best-fit line, and the measurement curve) of equal area. The intersection point of the best-fit line positioned in this way with the measurement curve yields the glass transition temperature.

[0105] Method 2 - Determination of molecular masses

[0106] The weight-average molecular weight M wThe measurements in this document refer to the conventional method of determination by gel permeation chromatography (GPC). The determination is carried out on 100 μl of a clear-filtered sample (sample concentration 3 g / l). Tetrahydrofuran is used as the eluent. The measurement is carried out at 25 °C.

[0107] The guard column is a column type PSS-SDV, 5 pm, 10 3 Ä, 8.0 mm * 50 mm (information here and below in the order: type, particle size, inner diameter * length; 1 Ä = 1 O -10 m). For separation, a combination of columns of the type PSS SDV, 5 pm, 10 3 Ä and 10 5 Ä and 10 6 Ä with 8.0 mm * 300 mm each (columns from Agilent; detection by means of differential refractometer PSS SECcurity 2). The flow rate is 1.0 ml per minute. Calibration is performed using the commercially available ReadyCal Poly(styrene) high kit from Agilent. This is universally converted to polymethyl methacrylate (PMMA) using the Mark-Houwink parameters K and alpha, so that the data are expressed in PMMA mass equivalents.

[0108] The polydispersity (PDI) is determined in a manner known to the person skilled in the art as the quotient of the weight-average and number-average molecular weight.

[0109] Method 3 - Dynamic Mechanical Analysis (DMA)

[0110] G' and G" are determined using a rheometer. The material under test is subjected to a sinusoidal oscillating shear stress in a plate-on-plate arrangement. Shear stress-controlled devices measure the deformation as a function of time and the temporal offset of this deformation relative to the application of the shear stress. This temporal offset is referred to as the phase angle δ.

[0111] The storage modulus G' is defined as follows: G' = (i7y) * cos(ö) (T = shear stress, y = deformation, ö = phase angle = phase shift between shear stress and deformation vector). The definition of the loss modulus G" is: G" = (T / Y) * sin(ö) (T = shear stress, y = deformation, ö = phase angle = phase shift between shear stress and deformation vector). tan ö = G“ / G'.

[0112] Device: deformation-controlled rheometer (ARES), plate-plate, o 25 mm

[0113] Deformation: 1%

[0114] Frequency: 10 rad / s.

[0115] Method 4 - Determination of static shear strength (shear life)

[0116] The shear strength is a measure of the internal strength of the adhesive and was tested in the so-called static shear test as follows, whereby the influence of a previous thermal load was also investigated:

[0117] The test was carried out under standard conditions (23 °C, 50 % relative humidity) using a weight of 1 kg.

[0118] 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 over it with a 2 kg roller (twice back and forth). The samples produced in this way were stored in an oven at 200 °C for 6 h and then equilibrated for 30 min under test conditions but without load. The test weight (1 kg) was then suspended so that a shear stress was applied parallel to the bonding surface, and the time until the bond failed was measured. The measurement result is given in minutes. The median of three individual measurements is given.

[0119] Preparation of polymer A

[0120] A 3-liter vessel conventional for radical polymerizations was charged with 900 g of isobornyl acrylate (IBOA), 10.395 g of dibenzyl trithiocarbonate (DBTTC), and 900 g of ethyl acetate (EtAc). After 45 minutes of nitrogen gas flow with stirring, the reactor contents were heated to 58 °C and 1.376 g of Vazo® 67 were added. The reactor contents were then heated further to 65 °C. After a reaction time of 24 h, the reactor contents were cooled to 35 °C. The conversion was > 95%, and the weight fraction of polymer A in the polymer solution was 50%.

[0121] Preparation of polymer B

[0122] A 3-liter vessel conventional for radical polymerizations was charged with 447.6 g of the solution of Polymer A, 676.2 g of n-butyl acrylate (nBA), and 676.2 g of ethyl acetate (EtAc). After 45 minutes of nitrogen gas flow with stirring, the reactor contents were heated to 58 °C and 0.258 g of Vazo® 67 was added. The reactor contents were then heated further to 65 °C. After 5 h, the mixture was diluted with 300 g of ethyl acetate. After a reaction time of 24 h, the reactor contents were cooled to 35 °C. The conversion was > 98%.

[0123] Preparation of polymer C

[0124] A 3-liter vessel conventional for radical polymerizations was charged with 900 g of n-butyl acrylate (nBA), 3.933 g of 1,4-phenylenebis(methylene)didodecyldicarbonotrithioate (BM1812®), and 900 g of ethyl acetate (EtAc). After passing nitrogen gas through the reactor for 45 minutes with stirring, the reactor contents were heated to 58 °C, and 0.229 g of Vazo® 67 was added. The reactor contents were then heated further to 65 °C. After a reaction time of 24 h, the reactor contents were cooled to 35 °C. The conversion was > 95%, and the weight fraction of polymer A in the polymer solution was 50%.

[0125] Preparation of polymer D

[0126] A 3-liter vessel conventional for radical polymerizations was charged with 1350 g of the polymer solution of Polymer C, 225 g of isobornyl acrylate (IBOA), and 225 g of ethyl acetate (EtAc). After 45 minutes of nitrogen gas flow 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 5 h, the mixture was diluted with 300 g of ethyl acetate. After a reaction time of 24 h, the reactor contents were cooled to 35 °C. The conversion was > 98%.

[0127] M w = 706,000 g / mol; PDI = 10.22

[0128] Table 1 : Weight-average molecular weight, polydispersity and shear stability time of the polymers

Claims

Patent claims 1. A process for producing a polymer system which is present in at least two phases, comprising the steps of: a) RAFT polymerization of a monomer composition I comprising a total of at least 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides and monomers having at least one polymerizable vinyl group to form a polymer A; and b) RAFT polymerization of a monomer composition II comprising a total of at least 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters, methacrylamides and monomers having at least one polymerizable vinyl group, the monomer composition II being present in at least 50% by weight.-% of its monomers differs from those of the monomer composition I, in the presence of the polymer A to a polymer B to obtain a polymer system present in at least two phases comprising the polymers A and B; characterized in that the RAFT polymerizations of steps a) and b) are carried out independently of one another in the presence of a RAFT regulator substance which, in its original state, has the general structure (I). R'-C(=S)-SR (I) or the general structure (II) R'-C(=S)-SR”-SC(=S)-R' (II), wherein the substituents R' independently of one another represent an aryl, aralkyl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio, alkoxy, alkaryloxy or alkenoxy radical or a radical (NR 1 )2, in which the substituents R 1independently of one another represent an alkyl or aryl radical or form with the N atom a heterocyclic ring having 1 to 3 heteroatoms, independently of one another selected from the group consisting of N, O and S; R represents a sec- or tert-alkyl radical, a cyano-sec-alkyl radical, a cyano-tert-alkyl radical, a carboxy-tert-alkyl radical, a carboxy-sec-alkyl radical, an aralkyl radical or a radical of the general structure (III) -CR 2 R 3 R 4 (III), where R 2 represents an alkyl radical or H, R 3 represents a cyano, carboxy or carboxylic acid ester group and R 4 represent an aryl radical; and R" for a group of the general structure (IV) -CR 5 R 6 -Y-CR 5 R 6 - (IV) where R 5 and R 6independently represent a hydrogen atom, an n-alkyl group, a cyano group, a carboxy group or a carboxylic acid ester group; and Y represents an alkylene or arylene group or a group having a structure selected from -(CH2)m-CO-O-(CH2)nO-CO-(CH2)m- and -(CH2) m -CO-NR 7 -(CH2) n - NO 7 -CO-(CH2) m -, where n is an integer from 1 to 12; m is 0 to 4 and R 7 represents an organyl radical; stands; 2. Process according to claim 1, characterized in that the substituents R' independently of one another represent an aryl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio or alkoxy radical or a radical (NR 1 )2, wherein the substituents R 1 independently represent an aryl residue.

3. Process according to claim 2, characterized in that the RAFT regulator substance in its original state corresponds to the general structure (I), in which R represents a cyano-tert-alkyl radical, a carboxy-tert-alkyl radical or a benzylthio radical.

4. Process according to claim 1, characterized in that the RAFT regulator substance in its original state corresponds to the general structure (II), in which the substituents R' are identical.

5. The process according to claim 4, characterized in that the substituents R' each represent an aryl, n-alkylthio, carboxy-n-alkylthio, carboxylic acid ester-n-alkylthio, hydroxy-n-alkylthio, arylthio or alkoxy radical or a radical (NR 1 )2, in which the substituents R 1 independently represent an aryl residue.

6. Process according to one of claims 4 and 5, characterized in that R" represents a group of the general structure (V) -CH2-Y-CH2- (V) stands.

7. Process according to one of claims 4 to 6, characterized in that R" represents a group of the general structure (IV) -CR 5 R 6 -Y-CR 5 R 6 - (IV) where Y represents an arylene group.

8. Process according to one of the preceding claims, characterized in that at least the RAFT polymerization of step b) is carried out in a solvent and process c) comprises removing the solvent under the action of temperature.

9. A polymer system present in at least two phases, preparable by a process according to any one of claims 1 to 8.

10. Use of a polymer system according to claim 9 as a component for producing a pressure-sensitive adhesive by means of a process comprising thermomechanically induced mixing of the components for producing the pressure-sensitive adhesive.

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