Pressure-sensitive adhesive substance

Abstract

The invention relates to a pressure-sensitive adhesive substance having a good adhesive strength, in particular on polar adhesive substrates; and good shear strength, in particular at room temperature and high temperature; and good peel adhesion, and can be made to a large extent from a bio-based raw material. The subject matter of the invention also comprises an adhesive tape comprising a carrier material and a pressure-sensitive adhesive substance according to the invention on at least one of the two outer sides thereof; the invention further relates to the use of the pressure-sensitive adhesive substance according to the invention or the adhesive tape according to the invention for producing adhesives in electronic, optical and / or precision mechanical devices.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure - sensitive adhesive substances, as they are commonly used for the temporary or permanent joining of components. More specifically, the present invention provides a pressure - sensitive adhesive substance based on a polyacrylate copolymer of a specific composition, which is capable of achieving good adhesion strength (adhesive force) together with good shear life and peel adhesion, especially on polar bonding substrates, wherein most of the polyacrylate copolymer is based on renewable raw materials. Background Art

[0002] In recent years, the demand for the quality of pressure - sensitive adhesive substances has increased sharply. Examples in this regard are the use of pressure - sensitive adhesive substances in electronic products such as smartphones and tablet computers. The adhesive should have significant adhesive - technical properties, such as high impact resistance, but must also be compatible with usually highly sensitive electronic components. Ecological and social standards are also attracting more and more attention, such as regarding the origin of raw materials. In this regard, there is a particular need for raw materials that are partially or even entirely of biological origin. This is part of the general current trend towards sustainable products and particularly addresses the limited oil reserves and the resulting need for conservation; customers of adhesive manufacturers are increasingly actively demanding corresponding products.

[0003] In the above aspects, poly(meth)acrylates have been repeatedly proven to be well - usable starting materials. Therefore, suitable formulations of pressure - sensitive adhesive substances based on poly(meth)acrylates are currently being studied.

[0004] For example, EP 2 062 955 A1 describes an aqueous pressure - sensitive adhesive substance that is essentially based on acrylate polymers dispersed in water.

[0005] For acrylate - based pressure - sensitive adhesive substances based on plant raw materials, it is typical for the adhesive composition to be based on a copolymer that includes the reaction products of 90 to 99.5% by weight of 2 - octyl (meth)acrylate, 0.5 to 10% by weight of (meth)acrylic acid, and less than 10% by weight of additional monomers, such as those described in WO 2008 / 046000 A1.

[0006] EP 3 013 767 A1 discloses the use of a polymer obtained by polymerizing 2 - octyl acrylate from renewable sources and optionally at least one additional monomer as an adhesive for the preparation of coating compositions, wherein the polymer has a glass transition temperature of - 30°C to 30°C.

[0007] EP 2 626 397 A1 discloses a pressure-sensitive adhesive composition comprising an acrylate-based polymer component, wherein at least 50% by weight of the monomers used to produce the polymer component are completely derived from renewable raw materials.

[0008] EP 4 196 509 A1 discloses a pressure-sensitive adhesive composition comprising at least one copolymer and at least one adhesion-enhancing resin (tackifying resin), the copolymer being traceable to a monomer composition comprising: 45 - 75% by weight of at least one monomer selected from isopentyl acrylate, n-heptyl acrylate, and 2-octyl acrylate; 24 - 50% by weight of at least one (meth)acrylic acid alkyl ester, the alcohol component of which has 1 to 4 C atoms; and 0.5 - 10% by weight of acrylic acid. SUMMARY OF THE INVENTION

[0009] The object of the present invention is to provide a pressure-sensitive adhesive composition which has good adhesive strength, especially on polar adhesion substrates; good shear life, especially at room temperature and high temperature; and good peel adhesion, and which can be produced to a large extent from biobased raw materials.

[0010] The first and general subject of the present invention for achieving the above object is a pressure-sensitive adhesive composition which comprises:

[0011] at least one copolymer A which is traceable to a monomer composition comprising:

[0012] a) in total 45 to 85% by weight of one or more monomers selected from isopentyl acrylate, n-heptyl acrylate, and 2-octyl acrylate;

[0013] b) in total 24 to 50% by weight of one or more (meth)acrylic acid alkyl esters, the alcohol component of which has 1 to 4 C atoms; and

[0014] c) 0.5 to 10% by weight of acrylic acid;

[0015] at least one rosin resin KH having a softening temperature in the range of 80 to 150 °C;

[0016] at least one coordination crosslinking agent; and

[0017] at least one covalent crosslinking agent.

[0018] This type of pressure-sensitive adhesive composition has good adhesive properties in accordance with the object of the present invention, wherein not only the (co)polymer component but also the resin part can be formulated to a large extent based on renewable raw materials.

[0019] As is generally said, a pressure-sensitive adhesive substance or a pressure-sensitive adhesive according to the present invention should be understood to mean a substance that is permanently sticky and adhesive at least at room temperature. A pressure-sensitive adhesive is characterized in that it can be applied to a substrate by pressure and adhere thereto, where the pressure to be applied and the duration of action of the pressure do not need to be defined in detail. Generally speaking, but basically depending on the exact type of the pressure-sensitive adhesive substance and the substrate, temperature and air humidity, and the substrate, the action of a short-term minimum pressure of gentle contact within no more than a short time is sufficient to achieve the adhesion effect. In other cases, a longer action time of a higher pressure may also be necessary.

[0020] The pressure-sensitive adhesive substance has specific characteristic viscoelastic properties, which result in permanent tackiness and adhesiveness. Their characteristic is that when they are mechanically deformed, both a viscous flow process and the formation of an elastic restoring force exist. The two processes are in a specific relationship with each other in terms of their respective proportions, depending not only on the exact composition, structure, and degree of crosslinking of the pressure-sensitive adhesive substance, but also on the rate and duration of deformation, and on temperature.

[0021] A certain proportion of viscous flow is necessary for the realization of adhesiveness. Only the viscous component (constituent) usually produced by macromolecules with relatively high mobility allows effective wetting of the substrate to be bonded and effectively flowing onto the substrate to be bonded. A high proportion of viscous flow results in high pressure-sensitive adhesiveness (also called tack or surface adhesiveness), and thus often also results in high adhesiveness. Highly crosslinked systems, crystalline or vitrified polymers lack a flowable component, and thus usually lack pressure-sensitive adhesiveness or have at least only slightly pressure-sensitive adhesiveness.

[0022] A certain proportion of elastic restoring force is necessary for the realization of cohesion. They are produced, for example, by macromolecules with very long chains and a high degree of entanglement, and by physically or chemically crosslinked macromolecules, and they allow the transmission of the forces acting on the adhesive bond. The said forces cause that the adhesive bond can sufficiently withstand the long-term loads acting thereon (for example in the form of long-term shear loads) for a relatively long time.

[0023] To more precisely describe and quantify the degree of the elastic and viscous components, and the relationship between the components, variables that can be measured by means of dynamic mechanical analysis (DMA) can be used: storage modulus ( ) and loss modulus ( ). is a measure of the elastic component of the substance, is a measure of the viscous component of the substance. Both parameters depend on the deformation frequency and temperature.

[0024] These variables can be determined with the aid of a rheometer. Here, for example, the material to be investigated is exposed to a sinusoidally oscillating shear stress in a plate-plate arrangement. In the case of an instrument operating in shear stress control, the deformation is measured as a function of time and the time shift of this deformation is measured relative to the introduction of the shear stress. This time shift is called the phase angle .

[0025] Storage modulus The following definition: ( = shear stress, = deformation, = Phase angle = Phase shift between shear stress vector and deformation vector). Loss modulus is defined as follows: ( = shear stress, = deformation, = Phase angle = Phase shift between shear stress vector and deformation vector).

[0026] In particular, when at 23°C for 10 0 Up to 10 1 rad / second (radians / second) deformation frequency range not only and Also at least partially located in 10 3 Up to 10 7 Pa, the substance is considered to be a pressure-sensitive adhesive substance and is particularly defined as such for the purposes of the present invention. "Partially" means, At least part of the curve lies between 10 0 (including endpoints) up to 10 1 (including the end points) rad / s deformation frequency range (abscissa) and the range from 10 3 (including endpoints) up to 10 7 Pa (including endpoints) The value range (ordinate) is within the window spanned by At least a portion of the curve is also located within the corresponding window.

[0027] The pressure-sensitive adhesive material according to the invention comprises at least one copolymer A traceable to a monomer composition comprising:

[0028] a) 45 to 85% by weight of one or more monomers selected from isoamyl acrylate, n-heptyl acrylate and 2-octyl acrylate,

[0029] b) from 24 to 50% by weight of one or more (meth)acrylic acid alkyl esters, the alcohol component of which has 1 to 4 C atoms, and

[0030] c) from 0.5 to 10% by weight of acrylic acid.

[0031] In particular, the monomers listed in a) can all be manufactured from renewable raw materials.

[0032] The process for manufacturing biobased acrylic acid (which can be used as monomer c) and the acid component of monomers a) and b)) is based on glycerol, which is produced in large quantities, for example, during the transesterification of vegetable oils with methanol to produce biodiesel and is thus available. The process comprises dehydrating glycerol to acrolein; and then oxidizing acrolein to acrylic acid (in a single-stage or two-stage process). Such a process is described, for example, in US 2007 / 0129570 A1.

[0033] WO 2006 / 092272 A2 discloses a similar process in which glycerol is first converted into a dehydration product containing acrolein, and then the dehydration product is subjected to gas-phase oxidation, where a product containing acrylic acid is produced. Acrylic acid is obtained by contacting the oxidation product with a quenching agent and treating the quenching phase. This process allows acrylic acid to be manufactured from renewable raw materials without using reactive compounds. Glycerol is preferably obtained from the saponification of animal or vegetable fats.

[0034] Biobased acrylic acid can also be obtained by a process in which lactic acid (2-hydroxypropanoic acid) or 3-hydroxypropanoic acid is produced from biological materials as a fluid (in particular in an aqueous phase), the hydroxypropanoic acid is dehydrated to obtain a fluid containing acrylic acid, and the fluid containing acrylic acid is purified. The required hydroxypropanoic acid can be prepared by fermentation. Due to the high selectivity of the microorganisms used, the fermentation process is generally highly selective, with high yields and few by-products. In addition, side reactions are also avoided by carrying out the fermentation process at a low temperature of 30 - 60 °C. On the other hand, large-scale chemical processes in the petrochemical industry are generally carried out at much higher temperatures of mostly > 200 °C to optimize yields. However, high reaction temperatures always lead to the formation of side reactions and cracking products.

[0035] For example, the process just described is described in DE 10 2006 039 203 A1, in which the purification of the fluid containing acrylic acid is carried out by suspension crystallization or layer crystallization.

[0036] To prepare alcohols from renewable raw materials, different processes can also be used.

[0037] For example, butanol can be obtained by fermentation of vegetable, usually pre-processed biomass. Here, for example, sucrose, starch or cellulose is used, and in some cases, genetically modified microorganisms (so-called "white biotechnology") are used. In the so-called A.B.E. process (A.B.E. stands for acetone, butanol, ethanol), the bacterium Clostridium acetobutylicum is used for fermentation to produce 1-butanol.

[0038] 2-Octanol can be obtained and separated as a by-product in the process of oxidizing ricinoleic acid to sebacic acid. n-Heptanol can be obtained from heptanal produced in the process of thermal cracking of ricinoleic acid (pyrolysis to produce heptanal and undecylenic acid).

[0039] Compared with the other monomers contained, monomer a) reduces the glass transition temperature of copolymer A. This is advantageous because it facilitates the application of the pressure-sensitive adhesive substance to the adhesive substrate. In addition, the substance can thereby absorb more resin, which also has a positive impact on the adhesive properties.

[0040] The monomer composition of copolymer A of the pressure-sensitive adhesive substance according to the invention comprises, according to the invention, a total of 45 to 85% by weight of monomer a). Preferably, the monomer composition of copolymer A of the pressure-sensitive adhesive substance according to the invention comprises a total of 55 to 75% by weight, in particular a total of 60 to 70% by weight, of monomer a). The monomer composition may essentially comprise one (single) or more monomers a).

[0041] Preferably, the monomer composition of copolymer A of the pressure-sensitive adhesive substance according to the invention comprises at least 2-octyl acrylate as monomer a). This is particularly advantageous because this monomer further reduces the glass transition temperature of copolymer A. In addition, it does not introduce side-chain crystallinity and thus makes a particularly large contribution to the development of pressure-sensitive adhesive properties. In particular, the monomer composition comprises 2-octyl acrylate as monomer a). This means that only 2-octyl acrylate is included as monomer a).

[0042] The monomer composition of copolymer A of the pressure-sensitive adhesive substance according to the invention further comprises one or more (meth)acrylic acid alkyl esters [monomer b)] whose alcohol component has 1 to 4 C atoms. The monomer composition of copolymer A of the pressure-sensitive adhesive substance according to the invention comprises a total of 24 to 50% by weight of monomer b). Preferably, the monomer composition of copolymer A of the pressure-sensitive adhesive substance according to the invention comprises a total of 25 to 40% by weight, in particular a total of 27 to 37% by weight, of monomer b). The monomer composition may essentially comprise one (single) or more monomers b).

[0043] Preferably, one or more alkyl (meth)acrylates whose alcohol component has 1 to 4 C atoms are selected from methyl acrylate, ethyl acrylate, n-butyl methacrylate and isobutyl acrylate. Particularly preferably, the monomer composition of copolymer A according to the invention comprises isobutyl acrylate and methyl acrylate as monomer b).

[0044] Monomer b) (in particular compared to monomer a)) increases the glass transition temperature of copolymer A. This is advantageous because the properties of the pressure-sensitive adhesive composition can be adjusted according to the corresponding requirements by changing the weight ratio of monomers a) and b). In addition, it is estimated that they introduce entanglement into the copolymer. This is advantageous because it imparts greater toughness and cohesion to the pressure-sensitive adhesive composition.

[0045] The monomer composition of copolymer A of the pressure-sensitive adhesive composition according to the invention comprises 0.5 to 10% by weight, preferably 1 to 7% by weight, particularly 2 to 4% by weight of acrylic acid.

[0046] Preferably, the monomer composition of copolymer A of the pressure-sensitive adhesive composition according to the invention consists of:

[0047] a) 60 to 75% by weight of one or more monomers selected from isopentyl acrylate, n-heptyl acrylate and 2-octyl acrylate,

[0048] b) 27 to 37% by weight of one or more alkyl (meth)acrylates whose alcohol component has 1 to 4 C atoms, and

[0049] c) 1 to 4% by weight of acrylic acid;

[0050] or consists of the above-mentioned preferred monomers in the proportions shown therein.

[0051] Copolymer A is preferably prepared by conventional free radical polymerization or controlled free radical polymerization. Copolymer A can be prepared by copolymerizing the monomers using conventional polymerization initiators and optionally regulators, wherein the polymerization is carried out at a conventional temperature in a substance, emulsion, such as water or a liquid hydrocarbon, or in solution.

[0052] Copolymer A is preferably prepared by copolymerizing the monomers in a solvent, particularly preferably in a solvent having a boiling range of 50 to 150 °C, especially 60 to 120 °C, using 0.01 to 5% by weight, especially 0.1 to 2% by weight (in each case based on the total weight of the monomers) of a polymerization initiator.

[0053] All customary initiators are suitable in principle. Examples of free radical sources are peroxides, hydroperoxides and azo compounds, such as benzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, di-tert-butyl peroxide, cyclohexylsulfonyl acetyl peroxide, diisopropyl percarbonate, tert-butyl peroctoate and benzoin. Preferred free radical initiators are 2,2'-azobis(2-methylbutyronitrile) ( ) or 2,2'-azobis(2-methylpropanenitrile) (2,2'-azodiisobutyronitrile; AIBN; ) from DuPont.

[0054] Preferred solvents for preparing copolymer A are: alcohols such as methanol, ethanol, n-propanol and isopropanol, n-butanol and isobutanol, especially isopropanol and / or isobutanol; hydrocarbons such as toluene, and especially petroleum spirit (benzine) having a boiling range of 60 to 120 °C; ketones, especially acetone, methyl ethyl ketone, methyl isobutyl ketone; esters such as ethyl acetate; and mixtures of the aforementioned solvents. Particularly preferred solvents are mixtures containing isopropanol in an amount of 2 to 15% by weight, especially 3 to 10% by weight, based on the solvent mixture used.

[0055] The copolymer A of the pressure-sensitive adhesive composition according to the invention preferably has a weight-average molecular weight Mw of more than 750,000 g / mol. The polydispersity (M w / M n ) of the copolymer is preferably from 130 to 170.

[0056] The pressure-sensitive adhesive composition according to the invention may essentially comprise one (single) or more copolymers A of the above type, preferably it exactly comprises one copolymer A of this type.

[0057] The pressure-sensitive adhesive composition according to the invention preferably comprises in total 50 to 90% by weight, more preferably in total 55 to 85% by weight, especially in total 60 to 80% by weight, very especially preferably 65 to 75% by weight of the above copolymer A, in each case based on the total weight of the pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition according to the invention particularly preferably (exactly) comprises one 50 to 90% by weight, more preferably 55 to 85% by weight, especially 60 to 80% by weight, very especially preferably 65 to 75% by weight of the above copolymer A, in each case based on the total weight of the pressure-sensitive adhesive composition.

[0058] One or more copolymers A of the pressure-sensitive adhesive material according to the present invention are preferably chemically crosslinked, in particular thermally crosslinked. "Thermal crosslinking" here means crosslinking with the aid of a substance that can (trigger) and / or promote a crosslinking reaction under the influence of thermal energy. Preferred thermal crosslinking agents are covalently reactive crosslinking agents, in particular epoxides, isocyanates and / or aziridines, and coordinated crosslinking agents, particularly preferably metal chelates, in particular aluminum, titanium, zirconium and / or iron chelates. Combinations of different crosslinking agents may also be used, for example a combination of one or more epoxides with one or more metal chelates.

[0059] The pressure-sensitive adhesive composition according to the invention comprises at least one coordination crosslinker and at least one covalent crosslinker.

[0060] In a preferred embodiment of the present invention, glycidylamine is used as the covalent crosslinking agent of the present invention. Particularly preferred representatives according to the present invention are, for example, N,N,N',N'-tetrakis(2,3-epoxypropyl)cyclohexane-1,3-dimethylamine and N,N,N',N'-tetrakis(2,3-epoxypropyl)-m-xylene-a,a'-diamine.

[0061] Advantageously, polyfunctional epoxides, in particular epoxycyclohexylcarboxylates, can be used as covalent crosslinkers. In particular, 2,2-bis(hydroxymethyl)-1,3-propanediol or (3,4-epoxycyclohexane)methyl-3,4-epoxycyclohexylcarboxylate are mentioned here as examples.

[0062] Furthermore, according to the invention, polyfunctional aziridines can be used. Here, trimethylolpropane tris(2-methyl-1-aziridine propionate) is mentioned, for example.

[0063] In another preferred embodiment of the present invention, isocyanate, in particular, a polyfunctional isocyanate compound is used as a covalent crosslinking agent. As the polyfunctional isocyanate compound, for example, toluene diisocyanate (TDI), 2,4-toluene diisocyanate dimer, naphthylene-1,5-diisocyanate (NDI), ortho-toluene diisocyanate (TODI), diphenylmethane isocyanate (MDI), triphenylmethane triisocyanate, tris-(p-isocyanatphenyl) thiophosphite, polymethylene polyphenyl isocyanate can be used. They can be used alone or in combination of two or more types thereof.

[0064] According to the invention, at least one covalent crosslinking agent is used, but it is also possible to use two or more covalent crosslinking agents, for example two of the above-mentioned diamine compounds in combination with one another.

[0065] As the coordination crosslinking agent of the present invention, chelates, especially polyvalent metal chelates, may be considered. The term "polyvalent metal chelate" should be understood to mean a compound in which a polyvalent metal is coordinately bonded to one or more organic compounds. As the polyvalent metal atom, Al(III), Zr(IV), Co(II), Cu(I), Cu(II), Fe(II), Fe(III), Ni(II), V(II), V(III), V(IV), V(V), Zn(II), In(III), Ca(II), Mg(II), Mn(II), Y(III), Ce(II), Ce(IV), St(II), Ba(II), Mo(II), Mo(IV), Mo(VI), La(III), Sn(II), Sn(IV), Ti(IV), etc. may be used. Among them, Al(III), Fe(III), Zn(II), Zr(IV) and Ti(IV) are preferred, and Fe(III) and Al(III) are particularly preferred.

[0066] In principle, all known ligands can basically be used as the ligands of the coordination crosslinking agent. However, the atoms for the coordination bonding of organic compounds can particularly be atoms having lone electron pairs, such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As the organic compound, for example, alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, ketone compounds, etc. can be used. In particular, examples should include iron(III) acetylacetonate (Fe chelate); titanium chelates such as dipropoxybis(acetylacetone)titanium, dibutoxybis(octylglycolato)titanium, dipropoxybis(ethylacetoacetate)titanium, dipropoxybis(lactic acid)titanium, dipropoxybis(triethanolamine)titanium, di-n-butoxybis(triethanolamine)titanium, tri-n-butoxymonostearate titanium, butyl titanate dimer, poly(acetylacetonato)titanium, etc.; aluminum chelates such as diisopropoxymonoethyl acetate aluminum (diisopropoxymonoethyl aluminum acetate); di-n-butoxymonoacetylacetate methyl aluminum, diisobutoxymonoacetylacetate methyl aluminum, di-n-butoxymonoacetylacetate ethyl aluminum, di-sec-butoxymonoacetylacetate ethyl aluminum, aluminum acetylacetonate, aluminum triethylacetylacetonate, monoacetylacetonedouble(ethylacetylacetone)aluminum, etc. and zirconium chelates such as zirconium tetraacetylacetonate, etc.

[0067] Among them, aluminum acetylacetonate (Al chelate) and aluminum dipropanolate are preferred. They can be used alone or in combination of two or more of these types.

[0068] The covalent crosslinking agent is preferably used in a total amount of 0.02 to 0.04 parts by weight, preferably 0.025 to 0.035 parts by weight, based on the total amount of 100 parts by weight of copolymer A.

[0069] The coordination crosslinking agent is preferably used in a total amount of 0.10 to 0.30 parts by weight, preferably 0.12 to 0.23 parts by weight, and particularly preferably 0.13 to 0.17 parts by weight, based on the total amount of 100 parts by weight of copolymer A.

[0070] Further preferably, the covalent crosslinking agent and the coordination crosslinking agent are used in such a way that the coordination crosslinking agent is present in a molar excess relative to the covalent crosslinking agent. Preferably, the crosslinking agents are used in such a way that the molar ratio is greater than 4.5 (4.5 < ), preferably greater than 5.0 (5.0 < ) and particularly preferably greater than 5.5 (5.5 < ).

[0071] Preferably, the crosslinking agents are used in the abovementioned amount ranges, i.e., in such a way that the molar ratio of the covalent crosslinking agent to the coordination crosslinking agent is greater than 4.5 (4.5 < ), preferably greater than 5.0 (5.0 < ) and particularly preferably greater than 5.5 (5.5 < ).

[0072] According to the general understanding of those skilled in the art, the adhesion-enhancing resin should be understood to mean an oligomeric or polymeric resin that increases the self-adhesion (tack, intrinsic tackiness) of the pressure-sensitive adhesive substance compared to a pressure-sensitive adhesive substance that does not contain the adhesion-enhancing resin but is otherwise identical. In addition, the adhesion-enhancing resin can also advantageously improve the wetting properties, flow behavior, and / or adhesion of the pressure-sensitive adhesive substance to the substrate to be adhered.

[0073] In principle, the adhesion-enhancing resin can be any tackifying resin that is compatible with the pressure-sensitive adhesive substance and particularly with one or more copolymers A of the pressure-sensitive adhesive substance.

[0074] The pressure-sensitive adhesive substance according to the invention comprises at least one rosin resin KH as the adhesion-enhancing resin, and the softening temperature range of the rosin resin is 80 - 150 °C.

[0075] Rosin resins are understood to mean the group of resins that include their disproportionated, hydrogenated, polymerized, modified derivatives, and salts.

[0076] The modified derivatives of rosin resins include esterified derivatives and / or further substituted derivatives, such as maleic ester resins (CAS: 68038 - 41 - 5).

[0077] Rosin resins can be used advantageously because they can be manufactured or obtained to a large extent, in particular entirely, from renewable raw materials. These tackifying resins can be made from renewable raw materials and have proven particularly suitable for improving the adhesive technical properties of the pressure-sensitive adhesive substances according to the invention to a certain extent.

[0078] Particularly preferably, the adhesion-enhancing resin is a fully hydrogenated rosin resin. This is particularly advantageous because these resins have a relatively low softening temperature and thus facilitate the development of the adhesive properties of the pressure-sensitive adhesive. In addition, they have particularly good aging stability.

[0079] The pressure-sensitive adhesive substance according to the invention can in principle comprise one (single) or more rosin resins KH.

[0080] The pressure-sensitive adhesive substance according to the invention can in principle comprise one (single) or more adhesion-enhancing resins.

[0081] Further adhesion-enhancing resins are, for example, aliphatic, aromatic and alkyl-aromatic hydrocarbon resins; hydrocarbon resins based on pure monomers; hydrogenated hydrocarbon resins; functional hydrocarbon resins and optionally derived natural resins; the tackifying resins are preferably selected from pinene, indene and rosin resins, their disproportionated, hydrogenated, polymerized, esterified derivatives and salts; aliphatic and aromatic hydrocarbon resins; terpene resins and terpene-phenolic resins and C5-, C9- and other hydrocarbon resins.

[0082] The pressure-sensitive adhesive substance according to the invention preferably comprises in total 10 to 55% by weight, more preferably in total 15 to 50% by weight, particularly in total 20 to 40% by weight, very particularly preferably in total 25 to 35% by weight of adhesion-enhancing resin, in each case based on the total weight of the pressure-sensitive adhesive substance.

[0083] The pressure-sensitive adhesive substance according to the invention particularly preferably comprises in total 10 to 55% by weight, more preferably in total 15 to 50% by weight, particularly in total 20 to 40% by weight, very particularly preferably in total 25 to 35% by weight of rosin resin KH, in each case based on the total weight of the pressure-sensitive adhesive substance.

[0084] The rosin resin KH according to the invention has a softening temperature of 80 - 150 °C, preferably 85 - 130 °C, very particularly preferably 90 - 110 °C.

[0085] The rosin resin KH according to the invention has a softening temperature of 80 - 150 °C, preferably 85 - 130 °C, very particularly preferably 90 - 110 °C, wherein the softening temperature is determined by the ring method ("ring ball") according to ASTM E28-18 (standard issued on July 01, 2018).

[0086] The pressure-sensitive adhesive substance according to the invention may also comprise further components, such as plasticizers; fillers, in particular fibres, coal ash (carbon black), zinc oxide, titanium dioxide, spinels, dyes, pigments, chalk, solid or hollow glass spheres, microspheres of other materials such as polymeric hollow spheres, silica and / or silicates; nucleating agents; blowing agents; compounding agents; stabilizers and / or anti-aging agents, such as primary and / or secondary antioxidants and / or light stabilizers.

[0087] The preparation of the pressure-sensitive adhesive substance according to the invention is preferably carried out starting from a solution, i.e. the components are dispersed or dissolved in a suitable solvent and mixed; after the mixing process is completed, the solvent is removed by conventional methods.

[0088] The pressure-sensitive adhesive substance according to the invention can be used, for example, in the form of a laminate of the pressure-sensitive adhesive substance according to the invention or a carrier-free layer (which is also referred to as a "transfer tape"). Such a transfer tape is preferably applied only to a material which is temporarily used to protect the adhesive surface in order to facilitate handling (transport) and easier application of the pressure-sensitive adhesive substance. This type of material is also referred to as a release liner or simply as a "liner", and is generally easily removable again, in particular by means of a suitable surface coating. The second side of the transfer tape can also be provided with a liner.

[0089] The release liner is in particular a one-sided or preferably two-sided anti-sticking (coated or treated) carrier material. As the carrier material for the release liner, various papers can be used, optionally also in combination with a stable extrusion coating. Other suitable liner carrier materials are films, in particular polyolefin films, such as films based on ethylene, propylene, butene and / or hexene. A preferred carrier material is paper, such as cellophane. Paper is also preferred because the concept of the source of components from renewable raw materials can thus also be extended to the auxiliary materials of the tape.

[0090] Silicone (organosilicon) systems are generally used as anti-sticking release coatings. Commonly used liners include, for example, silicone-coated papers and silicone-coated films.

[0091] In order to use the transfer tape for bonding to a substrate surface, the liner is then removed so that the two adhesive sides are in direct contact with the substrate surfaces to be bonded together respectively. Thus, the liner is not a product part and is therefore not counted as part of the tape, but only as an auxiliary tool for handling the tape.

[0092] Preferably, the pressure-sensitive adhesive substance according to the invention is used for constructing or for manufacturing a multi-layer tape. The corresponding multi-layer tape generally comprises at least one carrier layer and may have an outer layer of the pressure-sensitive adhesive substance according to the invention on one or both sides. In the case of a double-sided adhesive tape, one or both of the outer layers may be the pressure-sensitive adhesive substance according to the invention. In the latter case, the pressure-sensitive adhesive substance layers may differ in their chemical composition and / or their chemical and / or physical properties and / or their geometry (e.g., layer thickness), but are particularly preferably the same in their chemical composition and / or their chemical and / or physical properties. Even in the case of a multi-layer tape, the pressure-sensitive adhesive substance layer on one or even both outer sides may be covered with a backing.

[0093] The tape may have additional layers, such as additional carrier layers, functional layers, etc.

[0094] As the carrier material of the multi-layer tape, a bio-based material is preferably selected, for example, those selected from the list consisting of: paper; bio-based fabrics or non-woven fabrics, such as those made of cotton or viscose; cellophane; cellulose acetate; bio-based polyethylene films (PE) and polypropylene films (PP); films made of thermoplastic starch; bio-based polyester films, such as films made of polylactic acid (PLA), polyethylene terephthalate (PET), polyethylene furanoate (PEF) or polyhydroxyalkanoate (PHA). A particularly preferred carrier material is the PET film. PET films are preferred, for example, because they can be used as recycled materials and thus take into account the concept of sustainability in this way.

[0095] In one embodiment, the pressure-sensitive adhesive substance is characterized in that at least 50% by weight, preferably at least 60% by weight, particularly preferably more than 70% by weight of the monomers used for manufacturing copolymer component A are completely based on renewable raw materials.

[0096] In one embodiment, the pressure-sensitive adhesive substance is characterized in that the pressure-sensitive adhesive substance is based on renewable raw materials to an extent of at least 50% by weight, preferably at least 60% by weight, particularly preferably more than 70% by weight.

[0097] Compared with petrochemical products, those products made largely, preferably entirely, from renewable raw materials have a natural proportion of radioactive carbon atoms ( isotopes). The proportion of these isotopes can be determined and give an indication of the amount of natural raw materials used. Here, according to ASTM D6866-04, the radiocarbon method is used to determine the proportion of renewable raw materials. This method is based on the measurement of the isotope which in nature (i.e., biomass) at 10-10 is present in carbon with a probability of %. On the one hand, the half-life of 5730 years is long enough to ensure that within the time period of using conventional adhesive products such as pressure-sensitive tapes, the content will not change significantly due to decay (but short enough to determine the age of historical items made of biological materials). The measurement of the isotope is carried out using liquid scintillation spectrometry or mass spectrometry. Due to the above-mentioned half-life, in carbon samples over 60,000 years old, the isotope cannot be detected within the detection limit. Therefore, the carbon in petrochemical raw materials millions of years ago no longer contains the isotope. The same is true for raw materials based on natural gas and coal.

[0098] Therefore, another subject of the present invention is a tape, which includes a carrier material and a pressure-sensitive adhesive substance according to the present invention on at least one of its two outer sides, preferably on both outer sides. Preferably, the carrier material is a PET film. The PET film preferably has a thickness of 1 to 5 µm; the layer of the pressure-sensitive adhesive substance according to the present invention preferably has a layer thickness of 20 to 30 µm in each case. The preferred total thickness of the tape according to the present invention is thus 41 to 65 µm.

[0099] In order to anchor the pressure-sensitive adhesive substance to the carrier or other substrates, it may be preferable as follows: treating the substance and / or the substrate with corona or plasma before coating. In addition, in order to anchor the layer of the pressure-sensitive adhesive substance to another layer, especially to the carrier layer, it is preferable to carry out chemical anchoring, for example, through a primer.

[0100] Another subject of the present invention is the use of the pressure-sensitive adhesive substance according to the present invention in the manufacture of adhesions (or bonding parts) in electronics, optics, and / or precision machinery equipment.

[0101] In the sense of this application, electronics, optics, and precision machinery equipment are especially those classified in the International Classification of Goods and Services for the Purposes of the Registration of Marks (Nice Classification); Edition 10 (NCL(10-2013)), Class 9, provided that these are electronics, optics, or precision machinery equipment here; and clocks and timekeeping equipment according to Class 14 (NCL(10-2013)), such as especially

[0102] scientific, nautical, surveying, photographic, cinematographic, optical, weighing, measuring, signaling, monitoring, lifesaving, and teaching apparatus and instruments;

[0103] apparatus and instruments for conducting, switching, transforming, storing, regulating, and monitoring electricity;

[0104] image recording, processing, transmitting, and reproducing equipment, such as televisions, etc.;

[0105] Acoustic recording, processing, transmission, and reproduction devices, such as broadcasting equipment, etc.;

[0106] Computers, calculators, and data processing devices, mathematical devices and instruments, computer accessories, office instruments, such as printers, fax machines, copiers, typewriters; and data storage devices;

[0107] Telecommunication devices and multifunctional devices with telecommunication functions, such as telephones and answering machines;

[0108] Chemical and physical measurement devices, control devices and instruments, such as battery chargers, multimeters, lamps, and tachometers;

[0109] Navigation devices and instruments;

[0110] Optical devices and instruments;

[0111] Medical devices and instruments and those for sports people;

[0112] Watches and precision timepieces;

[0113] Solar cell modules, such as electrochemical dye-sensitized solar cells, organic solar cells, and thin-film cells; and

[0114] Fire extinguishing equipment.

[0115] At the same time, the technological development in the electronics industry often focuses on devices that are designed to be smaller and lighter, so that they can be carried around by their owners at any time. This is usually achieved by implementing a low weight or a suitable size for such devices. Such devices are also referred to as mobile devices or portable devices. In this context, precision mechanical and optical devices are also increasingly equipped with electronic components, which increases the possibility of miniaturization. Since mobile devices are carried around, they are subject to increased loads, such as by edge collisions, by dropping, by contact with other hard items in a bag, and also by the long-term movement caused by the carrying itself. However, compared to those "non-mobile (fixed)" devices that are usually installed inside and rarely move or do not move at all, mobile devices are also subject to stronger loads due to moisture exposure, temperature effects, etc. It has been proven that the pressure-sensitive adhesive substance according to the present invention is particularly preferably able to resist such interferences and attenuate or compensate for them. Therefore, the pressure-sensitive adhesive substance according to the present invention or the tape according to the present invention is preferably used for bonding in the manufacture of portable electronic devices.

[0116] Portable electronic devices are, for example:

[0117] Cameras, digital cameras, photographic accessories such as exposure meters, flashlights, apertures, camera housings, lenses, etc.; film cameras, video cameras;

[0118] Minicomputers (mobile computers, handheld computers, handheld calculators), laptops, notebooks, netbooks, ultrabooks, tablet computers, handheld devices, electronic organizers and managers (so-called "electronic organizers" or "personal digital assistants", PDAs, palmtop computers), modems;

[0119] Computer accessories and operating units for electronic devices, such as mice, drawing pads, graphics tablets, microphones, speakers, game consoles, joysticks, remote controllers, remote controls, touchpads ("touch pads");

[0120] Monitors, displays, screens, touch-sensitive screens (sensor screens, "touch screen devices"), projectors;

[0121] E-book reading devices ("e-books");

[0122] Miniature TVs, pocket TVs, movie playback devices, video players;

[0123] Radios (including mini radios and pocket radios), Walkmans, Discmans, music players for, e.g., CDs, DVDs, Blu-rays, tapes, USBs, MP3s; headphones;

[0124] Cordless telephones, mobile phones, smartphones, intercoms (two-way radios), hands-free telephones, pagers (beepers, callers);

[0125] Mobile defibrillators, blood glucose meters, blood pressure monitors, pedometers, pulse meters;

[0126] Flashlights, laser pointers;

[0127] Motion detectors, optical amplifiers, binoculars, night vision devices;

[0128] GPS devices, navigation devices, portable interface devices for satellite communication;

[0129] Data storage devices (USB sticks, external hard disk drives, memory cards); and

[0130] Watches, electronic watches, pocket watches, link watches, and stopwatches. Detailed implementation

[0131] Measurement and testing methods:

[0132] Static peel adhesion

[0133] Laminating a layer of pressure-sensitive adhesive substance onto a 125 µm polyimide carrier, for example Kapton 500HN. A strip of the 20 mm wide tape specimen was applied to a steel plate that had been washed twice with acetone and once with isopropyl alcohol, and then left in air for five minutes to allow the solvent to evaporate. The pressure-sensitive adhesive strip was rolled ten times on the substrate with a contact pressure equivalent to a 4 kg weight and exposed to a peel load after a tensioning time of two days. A 100 g weight was hung at one end of the tape, and the bonding assembly was inverted so that a 90° peel-off angle was formed. The test was carried out at 85 °C for 24 hours. Then the peel distance was measured in mm. A static peel adhesion of less than 15 mm was rated as good.

[0134] Determination of the glass transition temperature Tg of the pressure-sensitive adhesive substance

[0135] The static glass transition temperature of the pressure-sensitive adhesive substance is determined by dynamic differential calorimetry (DDK) or (synonymously) dynamic scanning calorimetry (DSC). For this purpose, a sample of approximately 5 mg of the untreated pressure-sensitive adhesive substance was weighed into an aluminum crucible (volume 25 µL) and the crucible was closed with a perforated lid. Measurements were carried out using a DSC 204 F1 from Netzsch GmbH. For inerting, the operation was carried out under nitrogen. First, the sample was cooled to -150 °C, then heated to +150 °C at a heating rate of 10 K / min and cooled again to -150 °C. The subsequent second heating curve was run again at 10 K / min and the change in heat capacity was recorded. The glass transition is considered here as a step in the thermogram (heat flow - temperature plot). The glass transition temperature Tg is obtained as follows: The linear ranges of the measurement curves before and after the step extend in the direction of the temperature increasing (region before the step) or decreasing (region after the step). In the region of the step, a fitting line is placed parallel to the ordinate so that it intersects the two extension lines, exactly such that two equal areas are formed (between the respective extension lines, the fitting line and the measurement curve). The intersection of the fitting line so positioned with the measurement curve gives the glass transition temperature.

[0136] Determination of the molecular weight

[0137] In this specification, the number-average molecular weight M n and the weight-average molecular weight M w values refer to the determination via gel permeation chromatography (GPC). The determination was carried out on 100 µl of a sample that had been subjected to clarification filtration (sample concentration 4 g / l). The eluent used was tetrahydrofuran with 0.1 volume % trifluoroacetic acid. The measurement was carried out at 25 °C.

[0138] The pre-column used was a PSS SDV type column, 5 µm, 10 3 , 8.0 mm x 50 mm (described hereinbelow and hereinafter in the following order: type, particle size, porosity, inner diameter x length; 1 = 10 -10 m). Separation was carried out using a combination of columns of type PSS SDV, 5 µm, 10 3 and 10 5 and 10 6 (each 8.0 mm x 300 mm) (columns from Polymer Standards Service; detected with a differential refractometer Shodex RI71). The flow rate was 1.0 ml / min. Calibration was carried out using the commercially available ReadyCal Kit Poly(styrene) high from PSS Polymer Standard Service GmbH, Mainz. Using the Mark-Houwink parameters K and universally converting it to polymethyl methacrylate (PMMA), thus providing data in terms of PMMA mass equivalent.

[0139] Determination of the K value

[0140] The K value according to Fikentscher is a measure of the molecular weight and viscosity of a polymer. The principle of this method is based on the capillary viscometry determination of the relative solution viscosity. For this purpose, the test substance was dissolved in toluene by shaking for 30 minutes to obtain a 1% concentration solution. In a Vogel-Ossag viscometer, the flow time was measured at 25 °C, and from this, the relative viscosity of the sample solution was determined relative to the viscosity of the pure solvent. The K value can be read from a table according to Fikentscher [P.E. Hinkamp, Polymer, 1967, 8, 381] (K = 1000 k).

[0141] Determination of tack

[0142] In this test, a steel ball weighing 5.6 g was rolled from a 65 mm inclined plane (inclination angle 21°) onto a horizontal strip of the adhesive substance to be tested. The distance to the point where the ball came to rest was measured (test climate 23 °C, relative humidity 50%). A distance of up to 300 mm was rated as a good result.

[0143] These balls were cleaned with pulp (Zellstoff) and acetone before measurement and conditioned openly in the test climate for 30 minutes.

[0144] The adhesive substance was conditioned in the test climate for 1 day before measurement.

[0145] Determination of Shear Life

[0146] The shear strength is determined in a test climate with a temperature of 23 + / - 1 °C and a relative humidity of 50% + / - 5%.

[0147] Cut the test sample to a width of 13 0.2 mm and store it in the climatic conditions for at least 16 hours. For the test, use a 50 x 25 mm ASTM steel plate with a thickness of 2 mm and a marked line of 20 mm, which is thoroughly cleaned several times with acetone before bonding and then left to dry for 10 minutes. The bonding area is 13 x 20 0.2 mm. Center the test strip on the adhesion substrate by scraping with a wiper in the longitudinal direction, avoiding air inclusions, so that the upper edge of the specimen is precisely aligned with the 20 mm marked line.

[0148] Cover the back of the specimen with aluminum foil. Paste the free protruding end with paper. Then roll the tape back and forth twice with a 2 kg roller. After rolling, attach a belt loop (weight 5 - 7 g) to the protruding end of the tape.

[0149] Then fix the adapter plate to the front of the shear test plate with screws and nuts. To ensure that the adapter plate is firmly fixed to the plate, tighten the screws firmly by hand.

[0150] The plate prepared in this way is connected to the counter clock via the adapter plate by means of a hook; then hang a 1 kg weight on the belt loop in a non - wobbling manner.

[0151] The tensioning time between rolling and loading is 12 minutes. Measure the time until bond failure (in minutes), and the measurement result is the average of three measurements. A shear life of at least 8000 minutes is considered a good result, and a shear life of at least 10000 minutes is rated as a very good result.

[0152] The determination of shear life at other temperatures is similar to the above method, where the prepared plate is equilibrated for 30 minutes at the test conditions, for example at 70 °C, before hanging the 1 kg weight. Therefore, a shear life of at least 100 minutes at 70 °C is rated as a good result.

[0153] Adhesive Force Steel

[0154] The measurement of the adhesion force is carried out in a test climate with a temperature of 23 °C ± 1 °C and a relative air humidity of 50% ± 5%. The sample is cut into a width of 20 mm and pasted onto a steel plate (ASTM). The steel plate is cleaned and conditioned before measurement. For this purpose, the plate is first wiped with a solvent and then left in the air for 5 minutes so that the solvent can evaporate. Then, the side of the tape facing away from the test substrate is covered with an etched PET foil with a thickness of 25 μm to prevent the sample from stretching during measurement. Then, the specimen is rolled onto the substrate. For this purpose, the tape is rolled back and forth 5 times with a 4 kg roller at a roller speed of 10 m / min. One minute after rolling, the plate is pushed into a specific holder. The adhesion force is measured using a Zwick tensile testing machine; the sample is 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 measurement values.

[0155] Table 1: Commercially available and used chemicals

[0156]

[0157] Preparation of polyacrylate and pressure-sensitive adhesive substances:

[0158] Polyacrylate P-I

[0159] A conventional 3-L container for free radical polymerization is filled with 30 g of acrylic acid (AA), 650 g of 2-octyl acrylate (2-OA), 220 g of isobutyl acrylate (iBA), 100 g of methyl acrylate (MA), and 724 g of mineral spirits / acetone (70:30). After passing nitrogen through for 45 minutes under stirring, the reactor is heated until 58 °C and 0.5 g is added. Subsequently, the jacket temperature is set to 75 °C and the reaction is carried out constantly at this external temperature. After a reaction time of 1 hour, another 0.5 g is added. After 3 hours, the reaction mixture is diluted with 200 g of mineral spirits / acetone (70:30), and after 6 hours, it is diluted with 100 g of mineral spirits / acetone (70:30). To reduce the residual initiator, 1.5 g is added at 5.5 hours and 7 hours respectively. The polymerization is terminated after a reaction time of 24 hours and cooled to room temperature. The K value is 82.

[0160] Polyacrylate P-II (comparative example from EP 3 417 005 B1)

[0161] A conventional 300-L container for free radical polymerization was filled with 2.0 kg of acrylic acid, 30.0 kg of isobornyl acrylate (BA), 68.0 kg of 2-ethylhexyl acrylate (EHA), and 72.4 kg of mineral spirits / acetone (70:30). After nitrogen was passed through for 45 minutes with stirring, the reactor was heated to 58 °C and 50 g was added. Subsequently, the jacket temperature was heated to 75 °C and the reaction was carried out constantly at this external temperature. After 1 hour of reaction time, another 50 g was added. After 3 hours, the reaction mixture was diluted with 20 kg of mineral spirits / acetone (70:30), and after 6 hours, it was diluted with 10.0 kg of mineral spirits / acetone (70:30). To reduce the residual initiator, 0.15 kg was added at 5.5 hours and at 7 hours respectively. After 24 hours of reaction time, the polymerization was terminated and cooled to room temperature. The molar mass determined by GPC: Mn = 62800 g / mol; Mw = 852600 g / mol. K value: 62.5.

[0162] Pressure-sensitive adhesive

[0163] According to Table 2, the polyacrylate was mixed with a tackifying resin and a crosslinking agent. The resulting composition was coated on a silicated release film (50 µm polyester) from the solution with a doctor blade, and then dried (coating speed 2.5 m / min, drying tunnel 15 m, temperature: zone 1: 40 °C, zone 2: 70 °C, zone 3: 95 °C, zone 4: 105 °C). The coating amount after drying was 50 g / m².

[0164] Table 2: Composition of pressure-sensitive adhesive substances

[0165]

[0166] In Table 2, "Control" means a control example

[0167] Table 3: Results

[0168]

[0169] In Table 3 represents very good; represents good; represents bad; "SSZ" represents shear life.

Claims

1. Pressure-sensitive adhesive substances, including: At least one copolymer A, traceable to a monomer composition comprising: a) 45 to 85% by weight in total of one or more monomers selected from isoamyl acrylate, n-heptyl acrylate and 2-octyl acrylate; b) 24 to 50% by weight in total of one or more alkyl (meth)acrylates, the alcohol component of which has 1 to 4 C atoms; and c) 0.5 to 10% by weight of acrylic acid; at least one rosin resin KH having a softening temperature in the range of 80 to 150° C.; at least one coordinating cross-linking agent; and At least one covalent cross-linking agent.

2. The pressure-sensitive adhesive material according to claim 1, characterized in that The softening temperature range of the rosin resin KH is 90° to 110°C.

3. The pressure-sensitive adhesive mass according to claim 1, characterized in that The molar ratio of the total amount of the coordination crosslinking agent to the total amount of the covalent crosslinking agent is greater than 4.5; preferably greater than 5.

0.

4. The pressure-sensitive adhesive mass according to any one of the preceding claims, characterized in that The coordinating crosslinkers are present in a total amount of 0.10 to 0.30 part by weight, preferably 0.12 to 0.23 part by weight, particularly preferably 0.13 to 0.17 part by weight, based on 100 parts by weight of the total amount of copolymer A.

5. The pressure-sensitive adhesive mass according to any one of the preceding claims, characterized in that The covalent crosslinking agent is present in a total amount of 0.02 to 0.04 parts by weight, preferably 0.025 to 0.035 parts by weight, based on 100 parts by weight of the total amount of copolymer A.

6. The pressure-sensitive adhesive mass according to any one of the preceding claims, characterized in that Al(III)-, Fe(II)-, Fe(III)-, Zn(II)-, Zr(IV)- and / or Ti(IV)-chelates are selected as coordinating crosslinkers, in particular aluminum(III) acetylacetonate or iron(III) acetylacetonate.

7. A pressure-sensitive adhesive mass according to any one of the preceding claims, characterised in that The following were selected as covalent crosslinking agents: N,N,N',N'-tetrakis(2,3-epoxypropyl)cyclohexane-1,3-dimethylamine, N,N,N',N'-tetrakis(2,3-epoxypropyl)-m-xylene-a,a'-diamine, 2,2-bis(hydroxymethyl)-1,3-propanediol, (3,4-epoxycyclohexane)methyl-3,4-epoxycyclohexylcarboxylate, trimethylolpropane tris(2-methyl-1-aziridine propionate), toluene diisocyanate (TDI) , 2,4-toluene diisocyanate dimer, naphthylene-1,5-diisocyanate (NDI), o-toluene diisocyanate (TODI), diphenylmethane isocyanate (MDI), triphenylmethane diisocyanate, tris(p-isocyanatophenyl)thiophosphite, polymethylene polyphenyl isocyanate, especially N,N,N',N'-tetrakis(2,3-epoxypropyl)-m-xylene-a,a'-diamine.

8. The pressure-sensitive adhesive mass according to any one of the preceding claims, characterized in that The monomer composition comprises in total 60 to 75% by weight of monomers a).

9. The pressure-sensitive adhesive mass according to claim 1, characterized in that The monomer composition comprises 2-octyl acrylate as monomer a).

10. The pressure-sensitive adhesive mass according to claim 1, characterized in that The monomer composition comprises in total 27 to 37% by weight of monomers a).

11. The pressure-sensitive adhesive mass according to claim 1, comprising in total 50 to 90% by weight, preferably 65 to 75% by weight, of copolymer A, based on the total weight of the pressure-sensitive adhesive mass.

12. The pressure-sensitive adhesive mass according to claim 1, comprising a total of 20 to 50% by weight, preferably 25 to 35% by weight, of one or more rosin resins KH, based on the total weight of the pressure-sensitive adhesive mass.

13. The pressure-sensitive adhesive mass according to any one of the preceding claims, characterized in that The pressure-sensitive adhesive substance is based to an extent of at least 50% by weight, preferably at least 60% by weight, particularly preferably more than 70% by weight, on renewable raw materials.

14. Adhesive tape comprising a carrier material and, on at least one of its two outer sides, a pressure-sensitive adhesive substance according to any one of claims 1 to 13.

15. Use of a pressure-sensitive adhesive mass according to any one of claims 1 to 13 or an adhesive tape according to claim 14 for producing bonds in electronic, optical and / or precision mechanical devices.

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