Reactive adhesive tape system

Abstract

The invention relates to a reactively curable adhesive tape system, to a method for adhering a first substrate X to a second substrate Y, and to the use of the reactively curable adhesive tape system. The reactively curable adhesive tape system according to the invention comprises A) a reactively curable adhesive tape containing a) at least one polymer, b) at least one radically polymerizable compound, and c) at least one initiator; and a primer composition containing d) at least one metal complex compound having a metal M selected from the group consisting of iron(III), copper(II), manganese(III), chromium(VI), titanium(III), manganese(IV), and cobalt(III), and e) at least one reducing agent for the metal M; or B) a reactively curable adhesive tape containing a) at least one polymer, b) at least one radically polymerizable compound, and d) at least one metal complex compound having a metal M selected from the group consisting of iron(III), copper(II), manganese(III), chromium(VI), titanium(III), manganese(IV), and cobalt(III); and a primer composition containing c) at least one initiator and e) at least one reducing agent for the metal M.

Description

[0001] tesa SE

[0002] Norderstedt

[0003] Reactive adhesive tape system

[0004] The invention relates to a reactively curable adhesive tape system, a method for bonding a first substrate X to a second substrate Y, and the use of the reactively curable adhesive tape system.

[0005] Reactive curing adhesives and adhesive tapes made from them are described in a number of prior art publications. In these processes, a reactive component—particularly based on acrylic monomers—is incorporated into a polymer matrix film in the presence of substances that, upon activation, cause the reactive curing of the adhesive but do not trigger a reaction in the storage state, i.e., without activation. The reaction—such as polymerization or curing—of the reactive component can be initiated by external influences—such as heat, humidity, plasma, radiation, and so on—or, for example, by bringing two layers of the aforementioned type, one containing an initiator and the other an activator, into direct contact, with the initiator being activated by the activator. This results in a two-component adhesive system in film form.

[0006] Such two-component adhesive systems based on acrylic monomers in the form of adhesive films (tapes) are described, for example, in WO 2014202402 A1, WO 2015062809 A1, WO 2018104053 A1.

[0007] WO 2019157265 A1 discloses a reactive curable adhesive system comprising a curable adhesive film containing a reducing agent and a liquid primer composition containing a metal complex and a peroxide compound.

[0008] A significant problem with the described two-component adhesive systems is the storage stability of the uncured adhesive tapes and, where applicable, liquid compositions. Furthermore, there is a need to further optimize the bond strengths achieved with a reactive curing two-component adhesive system.

[0009] The present invention is therefore based on the objective of providing a reactively curable adhesive tape system which exhibits improved storage stability. In particular, the aim is to achieve an adhesive strength that is as strong, or at least not significantly impaired, with an adhesive tape system stored for one or more weeks, for example one week, two weeks, four weeks or eight weeks, as with an unstored, freshly manufactured adhesive tape system using otherwise the same starting materials.

[0010] Furthermore, the bond strengths achievable with the adhesive tape system are to be further optimized.

[0011] An additional task is to provide a reactively curable adhesive tape system that can be cured at a low temperature, especially in a temperature range up to a maximum of 80 °C, so that substrates can be bonded together at low temperatures using the reactively curable adhesive tape system.

[0012] Another object of the present invention is therefore to provide a method for producing a bonded composite which can be carried out in a substrate-friendly manner.

[0013] The problems underlying the invention are solved by the reactively curable adhesive tape system according to claim 1. Furthermore, the problems are solved by the method for producing a bonded composite and the use of the reactively curable adhesive tape system according to the further independent claims.

[0014] All descriptions apply to the reactive adhesive tape system according to the invention, the method according to the invention for producing a bonded composite, and the use of the reactively curable adhesive tape system.

[0015] The invention also encompasses all features that are the subject of any dependent claims. Furthermore, the invention encompasses combinations of individual features with one another, including combinations of different levels of preference. Thus, the invention encompasses, for example, the combination of a first feature or embodiment designated as "preferred" with a second feature or embodiment designated as "particularly preferred." Advantageous embodiments of the reactively curable adhesive tape system apply to the inventive method and use, and vice versa.

[0016] The terms "reactive curing adhesive tape system" and "reactive adhesive tape system" are used synonymously within the scope of the present invention. Furthermore, for the sake of simplicity, the term "adhesive tape system" is also sometimes used synonymously. These synonymous terms apply analogously to a corresponding adhesive tape, an adhesive compound, an adhesive layer, and a primer composition.

[0017] The reactively curable adhesive tape system according to the invention comprises the mutually alternative variants A) and B), which are designed as follows.

[0018] The reactively curable adhesive tape system according to the invention comprises

[0019] A)

[0020] a reactive curing adhesive tape that

[0021] a) at least one polymer, and

[0022] b) at least one radically polymerizable compound, and

[0023] c) contains at least one initiator; and

[0024] a primer composition that

[0025] d) at least one metal complex compound with a metal M selected from the group consisting of iron(III), copper(II), manganese(III), chromium(VI), titanium(III), manganese(IV) and cobalt(III), and

[0026] e) contains at least one reducing agent for the metal M;

[0027] or

[0028] B)

[0029] a reactive curing adhesive tape that

[0030] a) at least one polymer, and

[0031] b) at least one radically polymerizable compound, and d) at least one metal complex compound containing a metal M selected from the group consisting of iron(III), copper(II), manganese(III), chromium(VI), titanium(III), manganese(IV) and cobalt(III); and

[0032] a primer composition that

[0033] c) at least one initiator, and

[0034] e) contains at least one reducing agent for the metal M.

[0035] Surprisingly, it has been found that the reactively curable adhesive tape system according to the invention has improved storage stability when - unlike in the prior art - the metal complex compound and the initiator, such as a peroxide compound, are not included together in the primer composition and instead the reducing agent for the metal M is included in the primer composition.

[0036] The primer composition, in particular, exhibits improved storage stability. With the adhesive tape system according to the invention, increased bond strengths are achieved compared to the prior art, especially after storage for several weeks. Bonded composites of two substrates produced using the adhesive tape system according to the invention show no decrease in bond strength compared to a freshly produced adhesive tape system, even after storage for, for example, one, two, four, or eight weeks. Furthermore, the adhesive tape system according to the invention cures even at relatively low temperatures, particularly at 23 °C (room temperature) up to a maximum of 80 °C. This enables the bonding of temperature-sensitive substrates.

[0037] The metal M in the metal complex compound is formally a metal cation in the corresponding oxidation state indicated in parentheses.

[0038] Iron(III) therefore means that it is a trivalent iron ion, i.e., Fe. 3+ , is involved. Analogously, the following applies:

[0039] Copper(II): divalent copper ion: Cu 2+ ,

[0040] Manganese(lll): trivalent manganese ion: Mn 3+ ,

[0041] Manganese(IV): tetravalent manganese ion: Mn 4+ ,

[0042] Chromium(VI): hexavalent chromium ion: Cr 6+ ,

[0043] Titanium(llll): trivalent titanium ion: Ti 3+ ,

[0044] Cobalt(lll): trivalent cobalt ion: Co 3+Without adhering to any specific theory, it is assumed that the aforementioned components react with each other as follows to achieve curing and thus bonding: The reducing agent converts the metal cation to a lower oxidation state. Upon contact of this reduced metal cation with the initiator, such as a peroxide, this leads to radical decomposition of the initiator, for example, into peroxide radicals. These radicals then initiate radical polymerization. Furthermore, the metal is reoxidized by the radical and can be reduced again by the reducing agent. This creates a redox cycle which, over a longer period, enables the progressive curing of the adhesive tape system. The redox cycle continues until the decomposition of the initiator, i.e., the peroxide decomposition, is complete.Once the initiator is consumed, the redox cycle comes to a standstill.

[0045] Preferably, and in particular, in the adhesive tape system according to the invention, the reducing agent and the initiator are each present in a molar excess to the metal complex compound before the start of the redox cycle.

[0046] For example, and preferably, the molar ratio of reducing agents e) to metal complex compounds d) is at least 1.7:1.

[0047] For example, and preferably, the molar ratio of initiators c) to metal complex compounds d) is at least 6:1.

[0048] The foregoing statements apply to both variants A) and B) of the adhesive tape system according to the invention.

[0049] The improved bond strengths achieved with the present invention are presumably due, among other things and in particular, to improved curing. Without wishing to be bound to a specific mechanism or theory, it is assumed that the increased storage stability ensures that sufficient molecules are available during subsequent use to maintain the redox cycle over a longer period.

[0050] Variants A) and B) represent alternatives to each other, as explained above.

[0051] Alternative A) is particularly preferred.

[0052] All statements regarding the adhesive tape system in general, the reactive curing adhesive tape and the primer composition apply to both alternatives A) and B).

[0053] The adhesive tape systems according to the invention are particularly suitable for miniaturized applications, such as those required in the electronics industry. Here, it is increasingly important to create highly precise and space-saving connections between components.

[0054] The general term "adhesive tape", also synonymously called "adhesive strip", encompasses, within the meaning of this invention, all planar structures, such as films or film sections extended in two dimensions, tapes with extended length and limited width, tape sections and the like, ultimately also die-cut pieces or labels.

[0055] The adhesive tape system according to the invention comprises a primer composition.

[0056] The term "primer" is known to those skilled in the art in connection with adhesive bonds. In the sense of the invention, the term "primer" means in particular a primer applied between two material layers which is able (either on a chemical or physical basis) to interact with the two material layers and enable their adhesion to one another.

[0057] A primer is generally considered a formulated product (usually containing more than one component) that is applied from the liquid phase using appropriate methods (immersion, brushing, spraying, etc.). According to this definition, the primer should not only enable adhesion but also form a uniform primer layer on the substrate surface by adjusting its wetting properties, drying rate, and other characteristics.

[0058] In this case, the primer's primary function is to enable bonding.

[0059] Within the scope of the present invention, the primer thus improves both the adhesion between the adhesive tape and the substrate and triggers and enables the described assumed mechanism for achieving reactive curing and thus bonding.

[0060] Only after contact between the adhesive tape and the primer are the three components – metal complex compound d), reducing agent for the metal M e) and initiator c) – present together, allowing the redox cycle to start and thus enabling curing by radical polymerization of the radically polymerizable compound.

[0061] Within the scope of the present invention, the composition of the primer is considered and described in particular with regard to its components and thus the “primer composition”.

[0062] The expression "at least one" or its equivalent "one or more" refers, in the usual industry practice, to the chemical nature of the substance in question and not to its quantity. It is clear to those skilled in the art that the expression "one initiator" therefore refers to a multitude of initiator molecules.

[0063] "Wt..-%" stands for weight percent, as usual. This applies to all versions.

[0064] Regarding the individual components

[0065] The adhesive tape of the reactive curing tape system is a reactive curing tape. Consequently, the reactive curing tape is based on a reactive curing adhesive compound, which is present in a layer of any desired geometry. The components of the adhesive tape are therefore also the components of the underlying reactive curing adhesive compound. The quantities specified refer to the total weight of the adhesive tape and thus of the reactive curing adhesive compound. Any carrier layers present are not included in the total weight of the adhesive tape when determining the quantities of the components, unless explicitly stated otherwise.

[0066] Within the scope of the present invention, the reactively curable adhesive tape is cured after and by contact with the primer composition, which is also a component of the reactive adhesive tape system according to the invention.

[0067] For this purpose, the chemical components are preferably contained either only in the adhesive tape or only in the primer composition or in the adhesive tape or the primer composition.

[0068] At least one polymer a)

[0069] The following statements apply to variant A) and variant B), unless explicitly stated otherwise.

[0070] According to the invention, at least one polymer a) is at least one component of the adhesive tape.

[0071] According to preferred embodiments, the primer composition does not contain a polymer a).

[0072] The product may contain one (single) polymer or several polymers. The description of "polymer" and the term "total quantity" thus encompass both the presence of a single polymer and the presence of multiple polymers. The terms "at least one," "one or more," or "exactly one" refer, in accordance with industry practice, to the chemical nature of the respective compounds and not to their quantity.

[0073] The adhesive tape preferably comprises 20 wt.% to 70 wt.% of at least one polymer a), more preferably the adhesive tape comprises 30 wt.% to 70 wt.% and particularly preferably 50 wt.% to 70 wt.% of at least one polymer a), in each case based on the total weight of the adhesive tape.

[0074] The weight percentages (wt%) refer to one polymer or to the sum of all polymers if two or more polymers are present.

[0075] Preferably the polymer(s) is / are selected from the group consisting of ethylene-vinyl acetate copolymers (EVA), poly(meth)acrylates, polyurethanes (PU), polyvinyl acetates (PVA), polyvinyl acetals, such as and in particular polyvinyl butyral (PVB), polyesters, acrylonitrile butadiene rubber (NBR) and polymers of monomers comprising N-vinyl compounds.

[0076] Particularly preferred is the polymer(s) selected from the group consisting of ethylene-vinyl acetate copolymers (EVA), poly(meth)acrylates, poly(N-vinylcaprolactam), poly(N-vinylpyrrolidone) and polyurethanes (PU).

[0077] According to preferred embodiments, the adhesive tape contains at least one polyurethane as polymer a).

[0078] Thermoplastic polyurethanes with a crystalline melting point of less than 100 °C and / or a softening point of less than 100 °C are preferred. In this context, the term softening point refers to the temperature at which the thermoplastic granules bond to themselves.

[0079] The crystalline melting temperature is determined by DSC as described in the methods section. Preferably, the polymer is a semicrystalline thermoplastic polymer.

[0080] In this case, in addition to its crystalline melting temperature (which is related to the melting of the crystallites), it very preferably has a glass transition temperature according to DSC of at most 25 °C, preferably at most 0 °C.

[0081] In preferred embodiments, at least one thermoplastic polyurethane is used. Commercially available thermoplastic polyurethanes include, for example, Desmocoll® 530 / 1 and Desmocoll® 540 / 3 as well as Desmomelt® 530 from Covestro AG (Leverkusen, Germany) or IROSTIC® S-6558 and IROSTIC® S 8612 from Huntsman (Huntsman Holland BV, Botlek-Rotterdam, Netherlands) or alternative variants from these product lines. Other available products include Elastollan® from BASF (Ludwigshafen, Germany) and Pearlbond from Lubrizol (Lubrizol Advanced Materials Europe BVBA, Brussels, Belgium).

[0082] Manufacturers also specify a minimum activation temperature in connection with polyurethanes.

[0083] Preferably, the thermoplastic polyurethane has a minimum activation temperature of less than 100 °C, particularly less than 80 °C. Preferred examples of such thermoplastic polyurethanes are Desmomelt® 530 and IROSTIC® S-6558. Desmomelt® 530 is a hydroxy-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer. According to the manufacturer, IROSTIC® S-6558 is a linear thermoplastic polyurethane for solvent-based adhesives. Its characteristics, according to the manufacturer, are: very low crystallization rate, long open time, and very low activation temperature.

[0084] According to preferred embodiments, the adhesive tape contains as polymer a) at least one polymer consisting of monomers comprising N-vinyl compounds.

[0085] Examples of such N-vinyl compounds are N-vinylacetamide (CAS No. 5202-78-8), N-vinylcaprolactam (CAS No.: 2235-00-9), N-vinylpyrrolidone (CAS No.: 88-12-0), N-vinyl-N-methylacetamide (CAS No. 3195-78-6), 5-methyl-3-vinyl-2-oxazolidinones (CAS No. 3395-98-0) or N-vinyl isobutyramide.

[0086] Preferred are N-vinyl-containing lactams and N-vinyl-containing oxazolidinones. It is advantageous if the N-vinyl compounds of the polymer are N-vinylcaprolactam (CAS No.: 2235-00-9), N-vinylpyrrolidone (CAS No.: 88-12-0), or 5-methyl-3-vinyl-2-oxazolidinones (CAS No.: 3395-98-0).

[0087] Preferred are N-vinylcaprolactam and / or N-vinylpyrrolidone, and the N-vinyl compound of the polymer N-vinylcaprolactam (NVC) is again preferred.

[0088] According to preferred embodiments of the invention, at least poly-N-vinylcaprolactam is thus contained in the adhesive tape as a polymer.

[0089] According to particularly advantageous embodiments of the invention, the polymer(s) is / are selected from the group consisting of poly(N-vinylcaprolactam) and polyurethanes (PU). According to particularly advantageous embodiments of the invention, the adhesive tape contains at least two different polymers, preferably poly(N-vinylcaprolactam) and polyurethanes (PU).

[0090] According to further particularly advantageous embodiments of the invention, the adhesive tape contains at least one poly(meth)acrylate.

[0091] The term "poly(meth)acrylate" refers to a polymer obtainable by polymerization, for example, radical polymerization, of acrylic and / or methacrylic monomers and optionally other copolymerizable monomers. In particular, "poly(meth)acrylate" refers to a polymer whose monomer base consists of at least 50 wt.% acrylic acid, methacrylic acid, acrylic esters, and / or methacrylic esters, wherein acrylic esters and / or methacrylic esters are present at least proportionally, preferably at least 30 wt.%, based on the total monomer base of the polymer in question.

[0092] The adhesive tape preferably contains at least one poly(meth)acrylate; therefore, it may contain one or more poly(meth)acrylates. The terms "at least one," "one or more," or "exactly one" refer, in accordance with industry practice, to the chemical nature of the respective compounds and not to their quantity. This also applies to the monomer composition of the poly(meth)acrylate.

[0093] For example, the monomer composition can consist exclusively of n-butyl acrylate as a monomer, which would mean that the monomer composition includes a variety of n-butyl acrylate molecules.

[0094] The poly(meth)acrylate(s) can in principle be any poly(meth)acrylate.

[0095] According to preferred embodiments of the invention, the poly(meth)acrylates contained therein can be produced by polymerization of a monomer composition containing one or more monomers selected from the group consisting of ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, iso-amyl acrylate, n-hexyl acrylate, 2-heptyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, iso-octyl acrylate, n-nonyl acrylate, iso-nonyl acrylate, n-decyl acrylate, iso-decyl acrylate,

[0096] 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate, 2-cyanoethyl acrylate,

[0097] 2-(2-Ethoxyethoxy)ethylacrylat, 2-Phenoxyethylacrylat, iso-Stearylacrylat, Docosylacrylat, 2-[2-(2-Methoxyethoxy)-ethoxy]ethylacrylat, Isobornylacrylat, Norbornylacrylat, Benzylacrylat, 3,3,5-Trimethylcyclohexylacrylat, Cyclohexylacrylat, 1 -Acryloyloxy-3-hydroxyadamantan, 4-[(6-Acryloyloxy)hexyloxy]4‘-cyanobiphenyl, N-Succinimidylacrylat,1 -Ethylcyclopentylacrylat, N-tert-Octylacrylamid, N-tert-Butylacrylamid, Dimethylacrylamid, Diethylacrylamid, N-iso-Propylacrylamid, N-Hydroxyethylacrylamid, Acrylamid, 2-Acrylamido-2-methylpropansulfonsäure, 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,

[0098] tert-Butylmethacrylat, Furfurylmethacrylat, 2-Methacryloyloxy-2-methyladamantan,

[0099] 2-Morpholinoethylmethacrylat, Phenylmethacrylat, N-Succinimidylmethacrylat,

[0100] 2-(tert-Butylamino)ethylmethacrylat, 2-Cyclohexylpropan-2-yl-methacrylat,

[0101] 1 -Adamantylmethacrylat, 1 -Methylcyclopentylmethacrylat,

[0102] N-tert-Butylmethacrylamid, N-(Methoxymethyl)methacrylamid, N,N-Dimethylmethacrylamid, Methacrylamid, N-Phenylmethacrylamid, N,N-Dimethylmethacrylamid, N-iso-Propylmethacrylamid, N-Vinylformamid, N-Vinylpyrrolidon, N-Vinylcaprolactam, N-Vinylcarbazol, N-Vinylimidazol, Vinylmethyloxazolidinon, N-Vinyl-N-methylacetamid, Hydroxyethylacrylat, Hydroxypropylacrylat, 4-Hydroxybutylacrylat, 2-Hydroxy-3-phenoxypropylacrylate, Hydroxyethylmethacrylat, Hydroxypropylmethacrylat, 4-Hydroxybutylmethacrylat, 2-Hydroxy-3-phenoxypropylmethacrylat, 4-Hydrxyethylacrylamid, Acrylsäure, Methacrylsäure, 2-Acryloyloxyethylsuccinat, Methacryloxyethylsuccinat, Sulfoethylmethacrylat, Methacrylamid, Glycidylacrylat, Glycidylmethacrylat, 3,4-Epoxycyclohexylmethylacrylat,

[0103] 3,4-Epoxycyclohexylmethylmethacrylat, 4-Hydroxybutylacrylateglycidylether,

[0104] 4-Hydroxybutylmethacrylate glycidyl ether, isocyanatoethyl acrylate, isocyanatoethyl methacrylate, 2-[2-(methacryloyloxy)ethyloxy]ethyl isocyanate, 2-[2-(acryloyloxy)ethyloxy]ethyl isocyanate and a, a -dimethyl-m-isopropenylbenzyl isocyanate.

[0105] According to preferred embodiments, the poly(meth)acrylates contained can be produced by polymerization of a monomer composition which contains benzyl acrylate and methyl methacrylate (MMA) as monomers.

[0106] According to further particularly advantageous embodiments of the invention, the adhesive tape contains at least one ethylene-vinyl acetate copolymer (EVA).

[0107] In principle, all ethylene-vinyl acetate copolymers known to those skilled in the art are conceivable. Suitable ethylene-vinyl acetate copolymers have a vinyl acetate content of 40 wt% to 90 wt%, with ethylene-vinyl acetate copolymers with, for example, 65 wt%, 70 wt%, and 80 wt% being particularly suitable. Such ethylene-vinyl acetate copolymers are commercially available from Arlanxeo under the trade names Levamelt® and Levapren® (Levamelt® 600, Levamelt® 700, and Levamelt® 800 are preferred).

[0108] Preferably, within the scope of the present invention, an ethylene-vinyl acetate copolymer with a vinyl acetate content of 60 to 90% is used.

[0109] Ethylene-vinyl acetate copolymers with a vinyl acetate content of less than 60% are also conceivable, but less preferred due to their higher crystallinity.

[0110] at least one radically polymerizable compound b)

[0111] The following statements apply to variant A) and variant B), unless explicitly stated otherwise.

[0112] According to the invention, at least one radically polymerizable compound b) is at least one component of the adhesive tape.

[0113] According to preferred embodiments, the primer composition does not contain a radically polymerizable compound b).

[0114] The term “polymerizable” refers, in accordance with expert understanding, to the ability of these compounds to undergo a polymerization reaction, possibly after suitable activation.

[0115] In accordance with expert understanding, the radically polymerizable compound should stand for a compound that is capable of undergoing a radical reaction, in particular a radical chain polymerization.

[0116] The adhesive tape preferably comprises 10 wt.% to 70 wt.% of at least one radically polymerizable compound b), more preferably the adhesive tape comprises 10 wt.% to 50 wt.% and particularly preferably 20 wt.% to 40 wt.% of at least one radically polymerizable compound b), in each case based on the total weight of the adhesive tape. In the case of two or more different radically polymerizable compounds b), the quantities refer to the total quantity of radically polymerizable compounds b). Preferably, the radically polymerizable compound b) is selected from the group consisting of radically polymerizable monomers, radically polymerizable oligomers and radically polymerizable polymers.

[0117] According to particularly advantageous embodiments, radically polymerizable monomers and / or radically polymerizable oligomers are preferred.

[0118] Preferably the radically polymerizable compound b) is from the group consisting of radically polymerizable monomers and radically polymerizable oligomers.

[0119] Preferably, the radically polymerizable monomer or oligomer is selected from the group consisting of acrylic acid esters, methacrylic acid esters, vinyl compounds, compounds with olefinic carbon-carbon double bonds, crosslinking radically polymerizable compounds, higher functional acrylates and higher functional methacrylates.

[0120] Crosslinking radically polymerizable compounds are in particular selected from the group consisting of diacrylates, dimethacrylates, triacrylates and trimethacrylates.

[0121] Here, "higher functional" acrylates or methacrylates are understood to be (meth)acrylates with four or more (meth)acrylate functional groups.

[0122] Particularly preferably, the radically polymerizable compound b) has at least one acrylate or methacrylate functional group. This applies to radically polymerizable monomers, oligomers, and polymers.

[0123] Thus, the radically polymerizable compound b) is preferably a radically polymerizable (meth)acrylate compound.

[0124] Oligomeric substances with acrylate or methacrylate functionalities are known to those skilled in the art and are also referred to as reactive resins. Here, too, the functionalization can be present in a single or multiple form within the molecule. According to advantageous embodiments, these are used in a mixture with at least one reactive monomer.

[0125] Preferred monomers for high bond strength are acrylic and / or methacrylic esters in which the alcohol portion of the ester contains aromatic structural elements, heteroatoms, or functional groups. Urethane groups, urea groups, oxygen or nitrogen heterocycles, ether groups, ester groups, acid functional groups, and / or hydroxyl functional groups are preferred. For good wet-heat resistance, acrylic and / or methacrylic esters in which the alcohol portion of the ester is a fatty alcohol are also preferred. Furthermore, for high crosslinking density, crosslinking monomers, and thus especially monomers with two or more (meth)acrylate functional groups, are preferred.

[0126] Examples of preferred monomers are 2-phenoxyethyl acrylate (CAS No.: 48145-04-6), 2-phenoxyethyl methacrylate (CAS No.: 10595-06-9), 2-hydroxy-3-phenoxy-propyl acrylate (CAS No.: 16969-10-1), 2-hydroxy-3-phenoxy-propyl methacrylate (CAS No.: 16926-87-7), 2-[2-(methacryloyloxy)ethoxycarbonyl]benzoic acid (CAS No.: 27697-00-3), 2-[[(phenylamino)-carbonyl]oxy]ethyl methacrylate (CAS No.: 51727-47-0), 2-Tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenylprop-2-enoate (CAS No.: 61167-58-6), (5-Ethyl-1,3-dioxan-5-yl)methyl acrylate (CAS No. 66492-51-1), (2-Oxo-1 ,3-dioxolan-4-yl)methyl methacrylate (CAS No.: 13818-44-5), di(ethylene glycol)-2-ethylhexyl ether acrylate (CAS No.: 117646-83-0), (2,2-dimethyl-1,3-dioxolan-4-yl)methylprop-2-enoate (CAS No.: 13188-82-4), 2-succinic acid mono-[2-(acryloyloxy)-ethyl ester] (CAS no.: 50940-49-3), 2-succinic acid mono-[2-(meth-acryloyloxy)ethyl ester] (CAS no.: 20882-04-6), (2,2-pentamethylene-1,3-oxazolidyl-3)ethyl methacrylate (CAS no.: 4203-89-8, 2-Hydroxy-3-(prop-2-enoyloxy)propyl-2-methyl-2-propyl-hexanoate (CAS No.: 444649-70-1), 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate (CAS No.: 63225-53-6), Stearyl acrylate (CAS No.: 4813-57-4), Stearyl methacrylate (CAS No.: 32360-05-7), and the crosslinking reactive monomers diurethane dimethacrylate (isomer mixture) (CAS No.: 72869-86-4), bisphenol A diglycidyl methacrylate (BIS-GMA, CAS No.: 1565-94-2), bisphenol A dimethacrylate (BIS-DMA, CAS No.: 3253-39-2), ethylene glycol diacrylate (CAS No.: 2274-11-5), ethylene glycol dimethacrylate (CAS No.: 97-90-5), trimethyloylpropane propoxylate triacrylate (CAS No.: 53879-54-2), trimethyloylpropane triacrylate (CAS No.: 15625-89-5) and / or di(trimethylolpropane)tetraacrylate (CAS No.: 94108-97-1).

[0127] Particularly preferred are 2-Hydroxy-3-phenoxy-propyl acrylate (CAS No.: 16969-10-1), 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate and diurethane dimethacrylate.

[0128] In advantageous embodiments, a reactively curable adhesive tape system is preferred, wherein the radically polymerizable compound b) is a radically polymerizable monomer selected from the group consisting of

[0129] 2-Methacryloxyethylphenylurethane, 2-phenoxyethyl acrylate,

[0130] 2-phenoxyethyl methacrylate, 2-hydroxy-3-phenoxy-propyl acrylate,

[0131] 2-Hydroxy-3-phenoxypropyl methacrylate,

[0132] 2-[2-(Methacryloyloxy)ethoxycarbonyl]benzoic acid,

[0133] 2-[[(Phenylamino)carbonyl]oxy]ethyl methacrylate,

[0134] 2-Tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenylprop-2-enoate, (5-ethyl-1,3-dioxan-5-yl)methyl acrylate, (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate, di(ethylene glycol)-2-ethylhexyl ether acrylate, (2,2-Dimethyl-1,3-dioxolan-4-yl)methylprop-2-enoate, 2-succinic acid mono-[2-(acryloyloxy)-ethyl ester],

[0135] 2-Succinic acid mono-[2-(methacryloyloxy)ethyl ester], (2,2-pentamethylene-1,3-oxazolidyl-3)ethyl methacrylate, 2-hydroxy-3-(prop-2-enoyloxy)propyl-2-methyl-2-propylhexanoate, 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate, stearyl acrylate, stearyl methacrylate, and the crosslinking reactive monomers diurethane dimethacrylate, bisphenol A diglycidyl methacrylate (BIS-GMA), bisphenol A dimethacrylate (BIS-DMA), ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethyloylpropane propoxylate triacrylate,

[0136] Trimethyloylpropane triacrylate and di(trimethylolpropane)tetraacrylate,

[0137] wherein 2-methacryloxyethylphenylurethane,

[0138] 2-hydroxy-3-phenoxy-propyl acrylate,

[0139] 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate and / or diurethane dimethacrylate are particularly preferred.

[0140] According to particularly advantageous embodiments of the invention, 2-hydroxy-3-phenoxy-propyl acrylate (HPPA) is included as b) a radically polymerizable compound.

[0141] According to particularly advantageous embodiments of the invention, the monomer 2-methacryloxyethylphenylurethane (MAPII) is included as b) a radically polymerizable compound.

[0142] This results in particularly high storage stability.

[0143] MAPII appears to work particularly well in small die-cut pieces. While not bound by theory, it is speculated that these monomers have a positive effect on the inhibition caused by atmospheric oxygen.

[0144] Radically polymerizable oligomers, in particular in contrast to polymers, are understood by those skilled in the art to be compounds that are radically polymerizable with a weight average of the molecular weight distribution M. waccording to GPC of less than 35000 g / mol, in particular less than 15000 g / mol, in particular less than 10000 g / mol.

[0145] Within the scope of the present invention, for example and in particular so-called urethane acrylates are preferred as oligomers.

[0146] These include aliphatic and aromatic polyester urethane (meth)acrylates, polyether urethane (meth)acrylates, polybutadiene urethane (meth)acrylates and silicone urethane (meth)acrylates; Available, for example, from Miwon, Bomar, and Allnex, such as the aliphatic polyester urethane MIRAMER SC2565 with a Mw of 5200 g / mol from Miwon, or the aliphatic urethane acrylates known under the trade names EBECRYL® 8402, EBECRYL® 4858, or EBECRYL® 8809 from Allnex, or the hydrophobic urethane acrylate BRC 843 from Bomar. Other preferred examples of radically polymerizable oligomers are aliphatic and aromatic polyester (meth)acrylates, such as the polyester acrylate EBECRYL® 5850 from Allnex, polyether (meth)acrylates, epoxy (meth)acrylates, amino (meth)acrylates, dendritic (meth)acrylates, and polycarbonate (meth)acrylates.

[0147] Other options include acrylated oligoesters, for example based on caprolactones, such as the commercially available hydroxyethylcaprolactone acrylate (HECLA; CAS No.: 110489-05-9).

[0148] The functionality of the polymerizable oligomers is preferred, i.e., the number of radically polymerizable groups per molecule is 1 to 20, usually 2 to 15, mainly 2 to 6. The dynamic viscosity, determined according to DIN 53019-1 from 2008, at 25°C is preferably greater than 1 Pa·s, but particularly preferably significantly greater than 10 Pa·s. Oligomers with dynamic viscosities at 25°C greater than 20 Pa·s, preferably greater than 30 Pa·s, are particularly suitable as components for the production of good pressure-sensitive adhesives with sufficient cohesion. Within the scope of the present invention, the dynamic viscosity is determined according to DIN 53019-1 from 2008 at 25°C with a shear rate of 1 s⁻¹. -1 certainly.

[0149] According to advantageous embodiments, the radically polymerizable compound b) is a radically polymerizable (meth-)acrylate-containing oligomer selected from the group consisting of aliphatic urethane diacrylates, polyether urethane diacrylates, polybutadiene urethane diacrylates, polyester urethane diacrylates, epoxy acrylates, amino acrylates, and acrylated oligoesters.

[0150] Preferably, the radically polymerizable (meth-)acrylate-containing oligomer exhibits a weight average of the molecular weight distribution M w according to GPC from 500 to 2000 g / mol.

[0151] According to advantageous embodiments, at least hydroxyethylcaprolactone acrylate (HECLA) is included as a radically polymerizable compound b).

[0152] According to particularly preferred embodiments, the adhesive tape contains at least the monomer 2-methacryloxyethylphenylurethane (MAPU) as the first radically polymerizable compound and at least hydroxyethylcaprolactone acrylate (HECLA) as the second radically polymerizable compound.

[0153] This results in particularly high storage stability and high bond strength.

[0154] According to further particularly preferred embodiments, the adhesive tape contains, as a radically polymerizable compound, at least one (meth)acrylate-containing oligomer based on aliphatic polyurethanes, in particular based on polyester polyurethanes, such as the aliphatic urethane diacrylate available under the trade name EBECRYL® 8809.

[0155] According to further preferred embodiments, the adhesive tape contains as the first radically polymerizable compound at least the monomer 2-methacryloxyethylphenylurethane (MAPI!) and at least one (meth)acrylate-containing oligomer based on aliphatic polyurethanes, in particular based on polyester polyurethanes, such as the aliphatic urethane diacrylate available under the trade name EBECRYL® 8809.

[0156] This results in particularly high storage stability and high bond strength.

[0157] Furthermore, the reactively curable adhesive tape may contain other radically polymerizable monomers or oligomers.

[0158] Preferably, however, no polymerizable (meth)acrylate compound containing an amine group is included. This applies to primary, secondary, and tertiary amines.

[0159] Furthermore, preferably no acid is present.

[0160] This means that preferably no amine or acid is added during the production of the adhesive tape.

[0161] At least one initiator c)

[0162] The reactive curing adhesive tape system contains at least one initiator.

[0163] According to variant A), at least one initiator c) is contained in the adhesive tape. In this variant, the primer composition contains no initiator and therefore 0 wt% initiators.

[0164] Preferably, the adhesive tape in variant A) contains 1 to 14 wt.%, particularly preferably 2 to 10 wt.%, most preferably 4 to 10 wt.%, and again preferably 6 to 8 wt.%, in each case based on the total weight of the adhesive tape, at least one initiator and the primer composition 0 wt.% of initiators.

[0165] According to variant B), at least one initiator is included in the primer composition. In this variant, the adhesive tape contains no initiator and therefore 0 wt% initiator.

[0166] Preferably, the primer composition in variant B) contains 1 to 14 wt.%, particularly preferably 2 to 10 wt.%, most preferably 4 to 10 wt.%, and again more preferably 6 to 8 wt.%, based on the total weight of the undried primer composition, of initiator c), and the adhesive tape contains 0 wt.% of initiators. Preferably, the primer composition in variant B) contains 75 to 95 wt.%, and particularly preferably 80 to 90 wt.%, based on the total weight of the dried primer composition, of initiator c), and the adhesive tape contains 0 wt.% of initiators.

[0167] In the case of two or more different initiators, the quantities specified for variant A) and variant B) are the total quantities of initiators in the adhesive tape and primer composition, respectively. The respective component of the adhesive tape system containing 0 wt% initiators contains no initiators capable of initiating the redox cycle described above, including the preferred initiators described below (c).

[0168] The initiator(s) c) are in particular radical initiators.

[0169] Preferably the initiator c) is at least a radical initiator selected from the group consisting of peroxides, persulfates, peroxomonosulfates, peroxodiphosphates, disulfides and dihales.

[0170] Particularly preferred is the initiator c) selected from the group consisting of peroxides. Hydroperoxides are particularly preferred, especially diisopropylbenzene hydroperoxide (CAS No. 26762-93-6). Diisopropylbenzene hydroperoxide is preferably in the form of a

[0171] 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, available under the trade name Peroxan® IHP-50.

[0172] α,α-Dimethylbenzyl hydroperoxide, also known as cumene hydroperoxide (CAS No. 80-15-9), can also be used. Furthermore, p-menthane hydroperoxide (CAS No. 26762-92-5), tert-amyl hydroperoxide (CAS No. 3425-61-4), or 1,1,3,3-tetramethylbutyl hydroperoxide (CAS No. 5809-08-5) can also be used, for example.

[0173] The initiator c) and all other components of the adhesive tape and primer composition are, in particular and preferably, not photoinitiators, i.e., not compounds that initiate the redox cycle described above upon contact with light. This allows the production of the adhesive tape and primer composition, as well as the process for producing the bonded composite, to be carried out under normal lighting conditions. Therefore, it is not necessary to ensure that the steps take place in the absence of light.

[0174] At least one metal complex compound d)

[0175] The reactive curing adhesive tape system contains at least one metal complex compound d). According to variant A), the at least one metal complex compound d) is contained in the primer composition. In this variant, the adhesive tape contains 0 wt.% of metal complex compounds, in particular metal complex compounds d).

[0176] Preferably, the primer composition in variant A) contains 0.5 to 5 wt.%, particularly preferably 0.5 to 3 wt.%, most preferably 0.5 to 2 wt.%, in each case based on the total weight of the undried primer composition, of metal complex compounds d) and the adhesive tape contains 0 wt.% of metal complex compounds, in particular metal complex compounds d).

[0177] Preferably, the primer composition in variant A) contains 40 to 60 wt.%, particularly preferably 45 to 55 wt.%, in particular 50 wt.%, in each case based on the total weight of the dried primer composition, of metal complex compounds d) and the adhesive tape contains 0 wt.% of metal complex compounds, in particular metal complex compounds d).

[0178] According to variant B), the at least one metal complex compound d) is contained in the adhesive tape. In this variant, the primer composition contains no metal complex compound, in particular no metal complex compound d), and thus 0 wt.% of metal complex compounds, in particular metal complex compounds d). Preferably, the adhesive tape in variant B) contains 0.5 to 5 wt.%, particularly preferably 1.25 to 5 wt.%, most preferably 1.25 to 3.5 wt.%, in each case based on the total weight of the adhesive tape, at least one metal complex compound d), and the primer composition contains 0 wt.% of metal complex compounds, in particular metal complex compounds d).

[0179] In the case of two or more different metal complex compounds d), the quantities given for variant A) and variant B) are each total quantities of metal complex compounds d) in the adhesive tape or in the primer composition.

[0180] The respective component of the adhesive tape system containing 0 wt.% of metal complex compounds does not contain any metal complex compounds that can participate in the redox cycle described above, including the metal complex compounds described below d).

[0181] In the context of the present invention, a “metal complex compound d)” is understood to be a metal complex compound comprising as its metal a metal M selected from the group consisting of iron(III), copper(II), manganese(III), chromium(VI), titanium(III), manganese(IV) and cobalt(III). The metal M in the metal complex compound is formally a metal cation in the corresponding oxidation state indicated in parentheses.

[0182] Iron(III) therefore means that it is a trivalent iron ion, i.e., Fe. 3+ , is involved. Analogously, the following applies:

[0183] Copper(II): divalent copper ion: Cu 2+ ,

[0184] Manganese(lll): trivalent manganese ion: Mn 3+ ,

[0185] Manganese(IV): tetravalent manganese ion: Mn 4+ ,

[0186] Chromium(VI): hexavalent chromium ion: Cr 6+ ,

[0187] Titanium(llll): trivalent titanium ion: Ti 3+ ,

[0188] Cobalt(lll): trivalent cobalt ion: Co 3+ .

[0189] A metal complex compound with a metal M selected from the group consisting of iron(III), copper(II) and manganese(III) is particularly preferred.

[0190] Since the metal complexes d), which are used within the scope of the present invention, thus formally comprise a positively charged metal atom and therefore a metal cation, the metal complex compound d) implicitly comprises one or more corresponding formally negatively charged counterion(s) and thus one or more anions for charge balance.

[0191] Preferably, the counterion to metal M in the metal complex compound d) is selected from the group consisting of acetylacetonates, fluorinated acetylacetonates, citrates, gluconates, tartrates, stearates, acetates, and ethylhexanoates. It is understood that the number of counterions is determined by their charge and the charge of the cation.

[0192] The counterion to metal M in the metal complex compound d) is particularly preferred and is selected from the group consisting of acetylacetonates, fluorinated acetylacetonates, acetates, and ethylhexanoates. It is understood that the number of counterions is determined by their charge and the charge of the cation.

[0193] According to particularly advantageous embodiments of the invention, the metal complex compound d) is selected from the group consisting of iron(III) acetylacetonate, manganese(III) acetylacetonate, copper(II) hexafluoroacetylacetonate, copper(II) ethylhexanoate, and copper(II) acetate. At least one reducing agent for the metal M e)

[0194] The following statements apply to variant A) and variant B), unless explicitly stated otherwise.

[0195] According to the invention, at least one reducing agent for the metal M e) is a component of the primer composition.

[0196] Preferably the adhesive tape contains no reducing agent for the metal M, in particular no reducing agent e), and thus 0 wt.% of reducing agents, in particular reducing agents e).

[0197] Preferably, the primer composition in variant A) contains 0.5 to 5 wt.%, particularly preferably 0.5 to 3 wt.%, and most preferably 0.5 to 2 wt.%, in each case based on the total weight of the undried primer composition, reducing agent e), and the adhesive tape contains 0 wt.% of reducing agents, in particular reducing agents e). Preferably, the primer composition in variant A) contains 40 to 60 wt.%, particularly preferably 45 to 55 wt.%, and in particular 50 wt.%, in each case based on the total weight of the dried primer composition, reducing agent e), and the adhesive tape contains 0 wt.% of reducing agents, in particular reducing agents e).

[0198] Preferably, the primer composition in variant B) contains 0.5 to 5 wt.%, particularly preferably 0.5 to 3 wt.%, most preferably 0.5 to 2 wt.%, in each case based on the total weight of the undried primer composition, of reducing agents e) and the adhesive tape 0 wt.% of reducing agents, in particular reducing agents e).

[0199] Preferably, the primer composition in variant B) contains 5 to 25 wt.%, based on the total weight of the dried primer composition, of reducing agents e) and the adhesive tape contains 0 wt.% of reducing agents, in particular reducing agents e).

[0200] In the case of two or more different reducing agents for the metal e), the quantities given for variant A) and variant B) are each total quantities of reducing agents e) in the primer composition.

[0201] The adhesive tape, which preferably contains 0 wt% reducing agents, contains no reducing agents that can participate in the redox cycle described above, including the reducing agents described below e).

[0202] In the context of the present invention, a “reducing agent for metal M” and thus a “reducing agent e)” is understood to be a compound capable of reducing the oxidation state of the specifically specified metal M of the metal complex compound d). Preferably, the reducing agent e) is selected from the group consisting of ascorbic acid (CAS No. 50-81-7), N-(diphenylmethylene)glycine ethyl ester (CAS No. 69555-14-2), α-acetylbutyrolactone (CAS No. 517-23-7), diphenylsilane (CAS No. 775-12-2), 3,5-diethyl-1,2-dihydro-1-phenyl-2-propylpyridine (CAS No. 34562-31-7).

[0203] N-(Diphenylmethylene)glycine benzyl ester (CAS No. 81477-91-0) and

[0204] 1,4-dihydro-2,6-dimethyl-3,5-pyridine dicarboxylic acid diethyl ester (CAS No. 1149-23-1).

[0205] In preferred embodiments, ascorbic acid is used as a reducing agent e). In particularly preferred embodiments, ascorbic acid is used as a reducing agent when the metal M of the metal complex compound is trivalent iron (iron(III)).

[0206] In preferred embodiments, a nitrogen-containing reducing agent e) is used, which is selected from the group consisting of

[0207] N-(diphenylmethylene)glycine ethyl ester, 3,5-diethyl-1,2-dihydro-1-phenyl-2-propylpyridine, N-(diphenylmethylene)glycine benzyl ester and

[0208] 1,4-dihydro-2,6-dimethyl-3,5-pyridine dicarboxylic acid diethyl ester.

[0209] In preferred embodiments, N-(diphenylmethylene)glycine ethyl ester is used as a reducing agent e).

[0210] In preferred embodiments, a nitrogen-containing reducing agent e) is used, which is selected from the group consisting of N-(diphenylmethylene)glycine ethyl ester, 3,5-diethyl-1,2-dihydro-1-phenyl-2-propylpyridine, N-(diphenylmethylene)glycine benzyl ester and 1,4-dihydro-2,6-dimethyl-3,5-pyridindicarboxylic acid diethyl ester, where the metal M of the metal complex compound is divalent copper (copper(II)).

[0211] In particularly preferred embodiments, N-(diphenylmethylene)glycine ethyl ester is used as a reducing agent e) when the metal M of the metal complex compound is divalent copper (copper(II)).

[0212] tape

[0213] The reactive curing adhesive tape or the reactive curing compound of the adhesive tape may optionally contain further additives and / or auxiliary materials. The proportion of these further additives and / or auxiliary materials may range from 0 wt.% to approximately 20 wt.%, preferably 0 wt.% to approximately 15 wt.%, more preferably 0 wt.% to approximately 10 wt.%, and most preferably 0 wt.% to approximately 5 wt.%, based on the total weight of the adhesive tape or the reactive curing compound.

[0214] lay.

[0215] Other additives and / or auxiliary substances include, for example, fillers, dyes, nucleating agents, rheological additives (for example, pyrogenic silica), blowing agents, adhesive-enhancing additives (adhesion promoters, especially silanes and tackifier resins), compounding agents, plasticizers and / or aging, light and UV protection agents, for example in the form of primary and secondary antioxidants.

[0216] In particular, and according to preferred embodiments, the proportion of fillers, such as glass beads or SiLibeads® 5211, is up to 50 wt.%, in particular up to 40 wt.%.

[0217] According to preferred embodiments, the adhesive tape or adhesive compound contains at least one rheology-modifying filler, such as silica in particular, preferably in an amount of 1 to 10 wt.%, more preferably 2 to 5 wt.%.

[0218] Preferably, the reactively curable adhesive of the tape is tacky, and thus preferably a pressure-sensitive adhesive, and the tape is therefore preferably a pressure-sensitive adhesive tape. This facilitates the processing and application of the tape, particularly in embodiments where the tape is used as a transfer tape.

[0219] The adhesive strength allows for reliable and safe application of the reactive adhesive tapes to the substrate before curing.

[0220] According to the invention, an adhesive compound is understood to be, as is generally accepted, a substance that is permanently sticky and adhesive, particularly at room temperature. A characteristic of an adhesive compound is that it can be applied to a substrate by pressure and adheres thereto, whereby the pressure to be applied and the duration of this pressure are not defined in detail. In some cases, depending on the exact type of adhesive compound, the temperature and humidity, and the substrate, the application of a short-term, minimal pressure, not exceeding a light touch for a brief moment, is sufficient to achieve the adhesive effect; in other cases, a longer duration of high pressure may be necessary.

[0221] Pressure-sensitive adhesives possess special, characteristic viscoelastic properties that result in their permanent tackiness and bonding strength. A defining characteristic is that when mechanically deformed, both viscous flow processes and the development of elastic restoring forces occur. The relative proportions of these two processes depend on the precise composition, structure, and degree of cross-linking of the pressure-sensitive adhesive, as well as the rate and duration of deformation and the temperature.

[0222] The proportion of viscous flow is necessary to achieve adhesion. Only the viscous components, caused by macromolecules with relatively high mobility, enable good wetting and flow onto the substrate to be bonded. A high proportion of viscous flow leads to high tack (also known as surface tack) and thus often also to high adhesive strength. Highly cross-linked systems, crystalline or glassy polymers, are generally not tacky or at least only slightly tacky due to a lack of flowable components.

[0223] The elastic restoring forces are necessary to achieve cohesion. They are generated, for example, by very long-chain and highly entangled macromolecules, as well as by physically or chemically cross-linked macromolecules, and enable the transmission of forces acting on an adhesive bond. This allows an adhesive bond to withstand a sustained load, such as continuous shear stress, to a sufficient degree over an extended period.

[0224] To more precisely describe and quantify the degree of elastic and viscous components, as well as their ratio, the storage modulus (G') and loss modulus (G"), which can be determined using Dynamic Mechanical Analysis (DMA, according to DIN EN ISO 6721-1:2019), can be used. G' is a measure of the elastic component, and G'' is a measure of the viscous component of a material. Both quantities depend on the deformation frequency and the temperature.

[0225] The properties can be determined using a rheometer. The material under investigation is subjected, for example, to a sinusoidally oscillating shear stress in a plate-plate arrangement. In shear-stress controlled devices, the deformation is measured as a function of time, along with the time lag of this deformation relative to the application of the shear stress. This time lag is called the phase angle θ.

[0226] The memory module G' is defined as follows:

[0227] G' = (T / y) • cos(θ) (T = shear stress, y = deformation, θ = phase angle = phase shift between shear stress and deformation vectors). The definition of the loss modulus G'' is:

[0228] G" = (T / Y) *sin(ö) (T = shear stress, y = deformation, ö = phase angle = phase shift between shear stress and deformation vector).

[0229] A material is generally considered to be adhesive and is defined as adhesive within the meaning of the invention if, at room temperature, here by definition at 23°C, in the deformation frequency range of 10° to 10 1 rad / sec G' at least partly in the range of 10 3 up to 10 7Pa lies within this range, and if G" also lies at least partially within this range. "Partially" means that at least a section of the G' curve lies within the window defined by the deformation frequency range from 10° inclusive to 10° inclusive. 1 rad / sec (abscissa) and the range of G' values ​​including 10 3 up to and including 10 7 Pa (ordinate) is spanned. The same applies to G".

[0230] Preferably, the adhesive compound exhibits in the deformation frequency range of 10° to 10 1 rad / sec at 23 °C a storage module G' and a loss module G" in the range of 10 3 up to 10 7 Pa, determined according to DIN EN ISO 6721-1 :2019.

[0231] To achieve viscoelastic properties, the monomers on which the polymers underlying the pressure-sensitive adhesive are based, as well as any other components of the adhesive, are selected such that the adhesive has a glass transition temperature (according to DIN 53765:1994-03) below the application temperature (i.e., usually below room temperature (23 °C)). By suitable cohesion-enhancing measures, such as crosslinking reactions (formation of bridge-forming links between the macromolecules), the temperature range in which a polymer compound exhibits pressure-sensitive properties can be increased and / or shifted. The application range of the pressure-sensitive adhesive can thus be optimized by adjusting the balance between flowability and cohesion.

[0232] In particular, an adhesive compound has a glass transition temperature of < 23 °C, determined according to DIN 53765:1994-03.

[0233] For simplification, the inventors define a reactive adhesive tape according to the present invention as preferably possessing an uncured adhesive strength of at least 1 N / cm and being removed almost without residue (i.e., adhesive failure in the test). The adhesive strength is determined on steel analogously to ISO 29862:2007 (Method 3) at 23 °C and 50% relative humidity, with a peel speed of 300 mm / min and a peel angle of 180°. An etched PET film with a thickness of 36 µm, available from Coveme (Italy), is used as the reinforcing film. A 2 cm wide test strip is applied using a 4 kg tape applicator at a temperature of 23 °C. The tape is peeled off immediately after application. The measured value (in N / cm) is calculated as the average of three individual measurements.Cohesive failure in this test is demonstrated by adhesives or tapes that are sticky at room temperature and whose cohesion is insufficient for residue-free removal. Such adhesives or tapes are not pressure-sensitive adhesives within the meaning of the invention.

[0234] The adhesive tape of the adhesive tape system according to the invention is preferably a double-sided adhesive tape. For the sake of simplicity, the adhesive tape is also referred to as "adhesive tape" in the double-sided embodiments within the scope of the present invention.

[0235] The adhesive tape can be supplied in any form, with rolls being preferred. The adhesive tape, particularly in roll form, can be manufactured either as a roll, i.e., wound around itself in an Archimedean spiral, or as adhesive strips, such as those obtained in the form of blanks or die-cuts.

[0236] Before cutting or die-cutting, the adhesive tape is primarily in roll form. A roll is defined as an object whose length (extension in the x-direction) is many times greater than its width (extension in the y-direction), and whose width is approximately, preferably exactly, constant along its entire length.

[0237] In addition to its longitudinal (x-direction) and lateral (y-direction) dimensions, the adhesive tape also has a thickness (z-direction) that runs perpendicular to both dimensions, with the lateral and longitudinal dimensions being many times greater than the thickness. The thickness is as uniform as possible over the entire surface area of ​​the adhesive tape, defined by its length and width, and preferably exactly uniform within tolerances.

[0238] The above applies analogously to the carrier layer(s) which, as a component of the adhesive tape according to some preferred embodiments, forms a layer in the x and y directions.

[0239] It is understood that the individual layers are arranged on top of each other along the z-direction.

[0240] According to preferred embodiments, the reactive curing adhesive tape comprises at least one carrier layer. Preferably, the carrier layer is surrounded on both sides by the described reactive curing adhesive compound, so that it is still a double-sided adhesive tape.

[0241] Preferably, the carrier layer is a fabric or a film, for example a polyester film, e.g. a PET film (PET = polyethylene terephthalate).

[0242] According to further preferred embodiments, the adhesive tape is a transfer adhesive tape. The adhesive tape thus consists continuously in the z-direction of a layer of a reactive curing adhesive compound with the components as described above.

[0243] Primer

[0244] The primer composition is liquid, especially at 23 °C and 1 bar atmospheric pressure.

[0245] According to preferred embodiments, the components of the primer composition, and thus components d) and e) according to variant A) or c) and e) according to variant B), are dissolved in a solvent. The solvent is preferably an organic solvent.

[0246] Preferably, and for example, the solvent is isopropanol.

[0247] However, the invention is not limited to these examples. It is understood that other solvents in which the respective components are soluble are also suitable.

[0248] The solvent evaporates, especially after the primer is applied, so that the primer or the applied primer layer dries.

[0249] Within the scope of the present invention, the undried primer composition is considered on the one hand, and the dried primer composition resulting from the evaporation of solvent on the other.

[0250] Proceedings

[0251] Another object according to the invention is, as described above, a method for producing a bonded composite, in particular for bonding a first substrate X with a second substrate Y.

[0252] The procedure includes at least the following procedural steps:

[0253] i.) Provision of a reactive curable adhesive system according to the invention; and ii.) Provision of a first substrate X; and

[0254] iii.) Application of the primer composition of the reactive curing adhesive system to a surface of the first substrate X; undiv.) Provision of a second substrate Y; and

[0255] v.) optionally applying the primer composition to a surface of the second substrate Y; and

[0256] vi.) Contacting the primer-treated surface of the first substrate X with a first surface of the adhesive tape of the reactive curing adhesive system; and vii.) Contacting the second substrate Y, optionally via its primer-treated surface, with a second surface of the adhesive tape of the reactive curing adhesive system; and

[0257] viii). Optionally, heating the arrangement comprising substrate X, the reactive curing adhesive tape system and substrate Y to a temperature preferably of no more than 80 °C.

[0258] Step i.) Provision of a reactive curable adhesive system according to the invention

[0259] The adhesive tape of the adhesive tape system according to the invention is produced in a manner known to those skilled in the art.

[0260] The adhesive mass of the adhesive tape is produced using known methods and applied in layered form, in particular by spreading.

[0261] In a first step, the ingredients are dissolved or finely dispersed in one or more organic solvents and / or water. Suitable solvents are known in the prior art, with solvents preferably used in which at least one of the ingredients exhibits good solubility. Acetone, ethyl acetate, and methyl ethyl ketone (MEK) are particularly preferred, for example. However, the invention is not intended to be limited to these exemplary solvents. It is understood that, depending on the polymer or other components, other solvents might be more suitable, which a person skilled in the art would readily consider.

[0262] As used herein, the term ingredient includes at least a) at least one polymer, b) at least one radically polymerizable compound, and c) at least one initiator (Variant A)) or at least one metal complex compound d) (Variant B), and in each case, optionally, further components such as rheology-modifying fillers, as defined above or preferably described.

[0263] Subsequently, in a second step, the dissolved or finely dispersed ingredients are mixed using conventional mixing equipment. Optionally, the ingredients are dissolved, finely dispersed, and mixed simultaneously. In a third step, a film, foil, layer, carrier, adhesive film, pressure-sensitive adhesive film, preferably a release liner or release paper, is coated with the mixture of dissolved, finely dispersed ingredients. The coating is carried out according to conventional techniques known in the prior art.

[0264] After coating, the solvent is removed in a fourth step by evaporation. Depending on the solvents used, this is preferably done at temperatures between 60 °C and 80 °C.

[0265] For storage, the resulting layer or the reactive adhesive tape according to the invention is covered with a separating liner or paper.

[0266] The primer composition is preferably prepared by dissolving the reducing agent e) and the metal complex compound d) (variant A) or the initiator (variant B)) each in a solvent and thoroughly mixing the solutions together. All details of the description regarding the primer composition apply.

[0267] Steps ii.) Provision of a first substrate X and iv.) Provision of a second substrate Y

[0268] The substrates X and Y to be bonded can be any type of substrate. For example, and preferably, they include metal, glass, painted or otherwise coated glass, ceramics, plastic components and / or metallized plastic components in electronic, optical and / or precision mechanical devices, automobiles, medical devices and dental devices.

[0269] Step iii.) Applying the primer composition of the reactive curing adhesive system to a surface of the first substrate X

[0270] The primer application according to step iii) is preferably carried out manually (e.g. by brushing or spraying) or mechanically (e.g. by coating or printing). If the primer contains solvents and / or water, it is then dried.

[0271] Applying the primer composition to a surface, for example, as in this case, to a substrate, in particular a component, thus results in a primer layer that is initially undried and has a certain layer thickness.

[0272] Preferably, the primer is applied using a printer, a dispensing nozzle, a squeegee, a brush or a suitable stick.

[0273] According to advantageous embodiments, the primer is applied using a guided dispensing nozzle, e.g., the "EV series automated dispensing systems" from Nordson EFD. According to further advantageous embodiments, the primer is applied using a printer.

[0274] Preferably, the primer is applied in a continuous (full-surface) layer to the substrate and / or the adhesive film or to the carrier layer and / or the adhesive film. Alternatively, preferably, the primer is applied at defined or arbitrary intervals in individual areas, for example in a circular pattern.

[0275] The thickness of the primer layer is determined using laser optics (CLSM (Convocal Laser Microscope, Keyence).

[0276] Before adding another layer to this primer layer, the primer layer is dried, as already described, in particular and preferably, resulting in a dried primer layer with a correspondingly reduced layer thickness.

[0277] The primer layer preferably has a thickness of 0.05 pm to 50 pm, particularly 0.05 pm to 10 pm, after drying.

[0278] According to advantageous embodiments, the primer layer has a thickness of 0.5 to 5 pm after drying.

[0279] Step v.) optionally applying the primer composition to a surface of the second substrate Y

[0280] Applying the primer composition to the second substrate Y is optional and depends in particular on the design and / or layer thickness of the adhesive tape as well as the nature of the substrate Y.

[0281] In the described embodiments, in which the reactively curable adhesive tape is a double-sided adhesive tape with a carrier layer, the primer composition is also applied to a surface of the second substrate Y.

[0282] This occurs particularly when the carrier layer is not permeable in the z-direction to the substances involved in the redox cycle described above, especially components c), d), and e). This ensures curing and bonding even on the surface of the second substrate Y.

[0283] For example, and particularly in the case of a PET film as a carrier layer that completely covers the x,y plane so that it is impermeable in the z direction, step v.) is therefore not optional. In the described embodiments, in which the reactively curable adhesive tape is a transfer adhesive tape, it depends in particular on the layer thickness whether the primer composition is preferably also applied to a surface of the second substrate Y.

[0284] In the case of a relatively thin transfer tape, such as one with a layer thickness in the z-direction of 10 pm to 100 pm, step v.) can be omitted. Due to the small layer thickness in the z-direction, sufficient migration of the reacting substances occurs from the interface between the first substrate X and the tape to the interface between the tape on the surface opposite substrate X and substrate Y. This allows for reactive curing and thus bonding even without additional application of the primer composition to substrate Y.

[0285] In the case of a comparatively thick transfer tape, such as with a layer thickness in the z-direction of more than 100 pm, it is preferred to carry out step v.) to ensure reactive curing and thus bonding between the tape on the surface opposite substrate X and substrate Y.

[0286] For the primer application to the second substrate Y, the explanations in step iv.) apply analogously.

[0287] Step vi.) Contacting the primer-treated surface of the first substrate X with a first surface of the adhesive tape of the reactive curing adhesive system

[0288] In principle, contacting can be carried out using all methods known to a person skilled in the art and with the aid of known devices and tools.

[0289] This contacting process creates the bonding surface that forms the bonded joint.

[0290] Step vii). Bringing the second substrate Y into contact, optionally via its primer-treated surface, with a second surface of the adhesive tape of the reactive curing adhesive system.

[0291] The explanations for step vi.) apply analogously.

[0292] Provided that, according to step v.), the primer composition has also been applied to the second substrate Y, the correspondingly primed surface is brought into contact with the second surface of the adhesive tape, which faces substrate X. Otherwise, any surface of the second substrate Y is to be bonded.

[0293] Step viii). Optionally, heating the assembly comprising substrate X, the reactive curing adhesive tape system, and substrate Y.

[0294] Following the steps i.) to vii.) described above, the reactive curing of the generated composite takes place to produce a bonded composite.

[0295] If this is not already achieved at room temperature by bringing the layers into contact with each other as described above, the arrangement comprising substrate X, the reactively curable adhesive tape system and substrate Y is preferably heated.

[0296] Preferably, the arrangement is heated to a temperature of no more than 80 °C in step viii. For example, and preferably, the temperature to which the arrangement is heated is 23 to 80 °C, particularly preferably 40 to 80 °C, and especially, for example, 60 °C.

[0297] This ensures that the curing process is fast enough but also gentle on the substrate.

[0298] Curing is also possible at lower temperatures, it just occurs more slowly due to the kinetics.

[0299] Furthermore, heating to over 80 °C is also conceivable in principle for less temperature-sensitive substrates.

[0300] Preferably, heating is carried out under simultaneous pressure. Preferably, a pressure of more than 1 bar is applied, particularly preferably 1 to 15 bar, and most preferably 3 to 15 bar.

[0301] Another object of the present invention is a bonded composite produced by the inventive method.

[0302] Another object of the present invention is the use of the adhesive tape or adhesive tape system according to the invention for bonding components in electronic, optical or precision mechanical devices, automobiles, medical devices and dental devices.

[0303] The reactive adhesive tape or adhesive tape system according to the invention is preferably used to produce bonds on materials selected from metal, glass, painted or otherwise coated glass, ceramic, plastic and metallized plastic, and the reactive adhesive tape or adhesive tape system according to the invention is used as an adhesive in the manufacture of electronic, optical and / or precision mechanical devices. Such portable devices are in particular:

[0304] Cameras, digital cameras, photography accessories (such as light meters, flash units, apertures, camera bodies, lenses, etc.), film cameras, video cameras, small computers (mobile computers, pocket computers, calculators), laptops, notebooks, netbooks, ultrabooks, tablet computers, handhelds, electronic calendars and organizers (so-called "Electronic Organizer" or "Personal Digital Assistants", PDA, palmtops), modems;

[0305] Computer accessories and control units for electronic devices, such as mice, drawing pads, graphics tablets, microphones, speakers, game consoles, gamepads, remote controls, remote controls, touchpads;

[0306] Monitors, displays, screens, touch-sensitive screens (sensor screens, "touchscreen devices"), projectors;

[0307] Reading devices for electronic books (“e-books”);

[0308] Small television sets, pocket televisions, film players, video players, radios (including small and pocket radios), Walkmans, Disemons, music players for e.g. CD, DVD, Blu-ray, cassettes, USB, MP3, headphones, cordless phones, mobile phones, smartphones, two-way radios, hands-free devices, personal alarm devices (pagers, beepers); mobile defibrillators, blood glucose meters, blood pressure monitors, pedometers, pulse monitors;

[0309] Flashlights, laser pointers;

[0310] Mobile detectors, optical magnifying devices, long-range vision devices, night vision devices, GPS devices, navigation devices, portable satellite communication interface devices;

[0311] Data storage devices (USB sticks, external hard drives, memory cards); and wristwatches, digital watches, pocket watches, chain watches, stopwatches.

[0312] The following are some examples to further illustrate the invention. Methods section - Testing methods

[0313] Unless otherwise stated, all measurements are taken at 23 °C and 50% relative humidity.

[0314] Molecular weight M n , M w of radically polymerizable compounds

[0315] The data on the numerical mean molecular weight M n or weight-average molecular weight M w In this document, the results refer to determination by gel permeation chromatography (GPC). The determination is performed on a 50 µL clear-filtered sample (sample concentration 3 g / L). Tetrahydrofuran is used as the eluent. The measurement is carried out at 35 °C. A column type SDV, 3 µm, 8.0 mm x 50 mm is used as the guard column (specifications here and in the following are in the order: type, particle size, porosity of separation columns, inner diameter x length; 1 Å = 10 -10m) is used. For separation, a combination of columns of type SDV, 3 pm, 10 is used. 3 Ä and 10 3 A and 10 4 Columns measuring 8.0 mm x 300 mm each were used (Agilent Technologies Inc. columns; detection using PSS SECcurity differential refractometer). 2 RI). The flow rate is 1.0 ml / min. Calibration is performed using the commercially available ReadyCal kit Poly(styrene) from Agilent Technologies Inc., so the data is given in polystyrene mass equivalents.

[0316] thickness

[0317] The thickness of an adhesive layer can be determined by measuring the thickness of a section of the adhesive layer applied to a liner, defined in terms of its length and width, and subtracting the (known or separately determinable) thickness of a section of the liner itself of the same dimensions. For non-tacky layers, a liner is not required, and the thickness can be measured directly. The thickness of the adhesive layer can be determined using commercially available thickness gauges (probe gauges) with accuracies of less than 1 µm. If thickness variations are detected, the mean value of measurements taken at at least three representative locations is reported, specifically excluding measurements taken at creases, folds, spots, and the like.

[0318] Just as the thickness of an adhesive layer can be determined, the thickness of an adhesive tape (adhesive strip) or a substrate can also be determined analogously using commercially available thickness gauges (touch-type testers) with accuracies of less than 1 pm deviation. If thickness variations are detected, the mean value of measurements taken at at least three representative locations is given, specifically excluding measurements taken at creases, folds, spots, and the like.

[0319] DSC

[0320] Glass transition points – also known as glass transition temperatures – of polymers or polymer blocks are determined by measurements using Dynamic Scanning Calorimetry (DSC) according to DIN 53765:1994-03, specifically sections 7.1 and 8.1, but with uniform heating and cooling rates of 10 K / min in all heating and cooling steps (see DIN 53765:1994-03; section 7.1; note 1). The sample weight is 20 mg. The melting point or softening point of polymers or polymer blocks is also determined in this way.

[0321] Adhesive strength - Push-Out

[0322] The push-out test allows statements to be made about the bond strength of a double-sided adhesive product in a bonded assembly in the direction of the adhesive layer normal.

[0323] A circular first substrate (S1) (SUS, VA-1.4301 steel (mirror polished on one side), 3 mm thick) with a diameter of 21 mm is provided, as well as a square second substrate (S2) (SUS, VA-1.4301 steel (mirror polished on one side), 2 mm thick) with a side length of 40 mm and with a circular, centrally located opening (bore) of 9 mm diameter.

[0324] Furthermore, the adhesive tape system to be examined, consisting of adhesive tape and primer composition, is provided.

[0325] The adhesive tape is provided in a ring shape with an outer diameter of 18 mm and an inner diameter of 13 mm, resulting in a ring with a web width of 5 mm.

[0326] Before the adhesive tape sample is applied, the surfaces of both substrates S1 and S2 to be bonded are cleaned with acetone and then conditioned for 1 hour at 23 °C and 50% relative humidity (evaporation time). The respective primer composition is then applied to both substrates S1 and S2 and dried for 1 hour under the same conditions (23 °C and 50% relative humidity). The adhesive tape is then applied, and a force of 100 N is applied to the specimen for 60 seconds at 60 °C to achieve compression. After compression, the specimens are conditioned for 24 hours at 23 °C and 50% relative humidity (RH).

[0327] The format of the frame (substrate S2) exceeds the format of substrate S1, so that the composite can be placed on a support table using the protruding areas of the frame (substrate S2).

[0328] Using a punch clamped in a tensile testing machine, a constant forward movement of the punch through the opening in substrate S2 exerts a force perpendicular to substrate S1, thus applying a force to the adhesive joint in the composite. The test speed of the punch is 10 mm / s. The maximum force at which substrate S1 detaches from the frame (substrate S2) is recorded. The force is related to the punch area, so that push-out strengths are expressed in units of N / mm². 2 or MPa result.

[0329] The test climate is 23 °C and 50% relative humidity.

[0330] This test is performed immediately after conditioning (“Initial”) and after storing samples of the same composition at room temperature after 1 week, after 2 weeks, after 4 weeks and after 8 weeks.

[0331] The values ​​given represent average values ​​from three measured test specimens.

[0332] Examples

[0333] The composition of the adhesive tape system was varied. For comparison, tests were also carried out that reflect the teaching of the prior art WO 2019157265 A1.

[0334] The variants A) and B) according to the invention were retained as designated in claim 1. Comparison systems, including that from WO 2019157265 A1, were designated C).

[0335] Within variant A), the individual components polymer a) and radically polymerizable compound b) were varied. Therefore, these variants were numbered, such as A1).

[0336] The substances used are listed in Table 1.

[0337]

[0338] The polymethacrylate was produced in the following way:

[0339] A conventional 4 L reactor for radical polymerizations was filled with 320 g of the monomer mixture listed in Table 1 and 273 g of ethyl acetate / isopropanol (96 / 04). After 45 minutes of nitrogen gas purging with stirring, the reactor was heated to 58 °C and 0.2 g of Vazo® 67 (2,2'-azobis(2-methylbutryonitrile)) was added. A further 480 g of the monomer mixture listed in Table 1 and 377 g of ethyl acetate were added continuously for 2 hours. Subsequently, the external heating bath was heated to 65 °C and the reaction was carried out at this constant temperature. After 1 h and after 1.5 h of reaction time, 0.3 g and 0.3 g of 2,2'-azobis(2-methylbutryonitrile) were added, respectively. To reduce the residual monomers, 0.12 g of di(4-tert-5-butylcyclohexyl)peroxydicarbonate was added after 6 h and again after 7.5 h. The mixture was diluted with 160 g of ethyl acetate once after 2 h and once after 4 h.The reaction was stopped after 24 hours and cooled to room temperature.

[0340] The compositions of the adhesive tape systems are shown in Tables 2 and 3. Table 2 summarizes the variants according to the invention A1), B) and comparative systems of composition C). Table 3 lists the numbered variants A) and the results of the bond strength tests for these variants.

[0341] The results of the bond strength tests for the remaining examples are summarized in Table 4, which also includes more detailed information on the individual substances in each variant that is not yet apparent from Table 2. The compositions of these examples can be determined by comparing Tables 2 and 4.

[0342] All quantities are given in wt.%, where the sum of the quantities in the adhesive tape alone equals 100 wt.% and the sum of the quantities in the primer composition also alone equals 100 wt.%.

[0343] All information regarding the bond strengths “initial” and after storage for the specified number of weeks is given in the unit MPa.

[0344] Examples in accordance with the invention are marked with "E". Comparative examples are marked with "V".

[0345] The adhesive tapes and primer compositions were manufactured in the following manner:

[0346] Adhesive tapes

[0347] The reactive adhesives for the tapes were prepared in the laboratory according to the percentage proportions listed in the tables. The remaining raw materials were added to the prepared polymers in solvent. If commercial polymers were used, they were prepared as a 40% solution in solvent. The amount of solvent in the undried adhesive is not specified in the tables. The finished adhesive formulation is spread onto a siliconized liner, and two spreads are laminated together with 12 µm PET film as a backing material to form a double-sided tape.

[0348] Primer

[0349] A 2.5% solution of each metal complex and a 2.5% solution of each reducing agent were prepared in isopropanol. Once the substances were completely dissolved, the solutions were mixed in a 1:1 volume ratio and then applied to the respective substrate using a cleanroom swab. After a drying time of at least 20 minutes at room temperature, the adhesive tape was applied.

[0350] Table 2

[0351]

[0352] Table 3

[0353]

[0354] Table 4

[0355]

[0356] In comparative examples V1 to V3, the primer is composed as in the prior art (metal salt + initiator). Initially, this variant also leads to the curing of the adhesive tape, as evidenced by values ​​of 2 to 5 MPa. However, the primer solution does not appear to be stable over time, as a primer solution that is four weeks old results in significantly lower bond strengths.

[0357] In contrast, the mixing or distribution of the three components c), d) and e) according to the invention onto the adhesive tape and primer leads both to storable primer solutions, as evidenced by the stable values ​​even with primer solutions that are 8 weeks old, and to significantly higher initial bond strengths compared to the prior art (V1). This is surprising, since exactly the same adhesive tape compositions were chosen.

[0358] This improvement in shelf life, combined with a significant improvement in bond strength, was achieved both with primer solutions containing metal complex and reducing agent (E1, E3, E5, E6) according to variant A) and with primer solutions containing reducing agent and radical initiator (E2, E4) according to variant B).

[0359] As can be seen from Table 3, the improved bond strengths of the system according to the invention are achieved with different selected polymers and radically polymerizable compounds.

Claims

Patent claims 1. Comprehensive reactive curing adhesive tape system A) a reactive curing adhesive tape that a) at least one polymer, and b) at least one radically polymerizable compound, and c) contains at least one initiator; and a primer composition that d) at least one metal complex compound with a metal M selected from the group consisting of iron(III), copper(II), manganese(III), chromium(VI), titanium(III), manganese(IV) and cobalt(III), and e) contains at least one reducing agent for the metal M; or B) a reactive curing adhesive tape that a) at least one polymer, and b) at least one radically polymerizable compound, and d) contains at least one metal complex compound with a metal M selected from the group consisting of iron(III), copper(II), manganese(III), chromium(VI), titanium(III), manganese(IV) and cobalt(III); and a primer composition that c) at least one initiator, and e) contains at least one reducing agent for the metal M.

2. Reactively curable adhesive tape system according to claim 1, characterized in that the initiator c) is a radical initiator selected from the group consisting of peroxides, persulfates, peroxomonosulfates, peroxodiphosphates, disulfides and dihalogens, wherein the initiator c) is particularly preferably selected from the group consisting of peroxides.

3. Reactive curable adhesive tape system according to claim 1 or 2, characterized in that the polymer a) is selected from the group consisting of ethylene-vinyl acetate copolymers (EVA), poly(meth)acrylates, polyurethanes (PU), polyvinyl acetates (PVA), polyvinyl acetals, such as and in particular polyvinyl butyral (PVB), polyesters, acrylonitrile butadiene rubber (NBR) and polymers of monomers comprising N-vinyl compounds, wherein the polymer is particularly preferably selected from the group consisting of ethylene-vinyl acetate copolymers (EVA), poly(meth)acrylates, poly(N-vinylcaprolactam), poly(N-vinylpyrrolidone) and polyurethanes (PU).

4. Reactively curable adhesive tape system according to one of the preceding claims, characterized in that the radically polymerizable compound b) is selected from the group consisting of radically polymerizable monomers and radically polymerizable oligomers.

5. Reactively curable adhesive tape system according to claim 4, characterized in that the radically polymerizable monomer or oligomer is selected from the group consisting of acrylic acid esters, methacrylic acid esters, vinyl compounds, compounds with olefinic carbon-carbon double bonds, crosslinking radically polymerizable compounds, higher functional acrylates and higher functional methacrylates.

6. Reactively curable adhesive tape system according to claim 5, characterized in that the radically polymerizable compound b) contains a radically polymerizable monomer selected from the group consisting of 2-Methacryloxyethylphenylurethane, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2-hydroxy-3-phenoxy-propyl acrylate, 2-Hydroxy-3-phenoxypropyl methacrylate, 2-[2-(Methacryloyloxy)ethoxycarbonyl]benzoic acid, 2-[[(Phenylamino)carbonyl]oxy]ethyl methacrylate, 2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenylprop-2-enoate, (5-Ethyl-1,3-dioxan-5-yl)methyl acrylate, (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate, di(ethylene glycol)-2-ethylhexyl ether acrylate, (2,2-dimethyl-1,3-dioxolan-4-yl)methylprop-2-enoate, 2-succinic acid mono-[2-(acryloyloxy)-ethyl ester], 2-Succinic acid mono-[2-(methacryloyloxy)ethyl ester], (2,2-pentamethylene-1,3-oxazolidyl-3)ethyl methacrylate, 2-hydroxy-3-(prop-2-enoyloxy)propyl-2-methyl-2-propylhexanoate, 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate, stearyl acrylate, stearyl methacrylate, and the crosslinking reactive monomers diurethane dimethacrylate, bisphenol A diglycidyl methacrylate (BIS-GMA), bisphenol A dimethacrylate (BIS-DMA), ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethyloylpropane propoxylate triacrylate, trimethyloylpropane triacrylate and di(trimethylolpropane)tetraacrylate, wherein 2-methacryloxyethylphenylurethane, 2-Hydroxy-3-phenoxypropyl acrylate, 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate and / or diurethane dimethacrylate are particularly preferred.

7. A reactively curable adhesive tape system according to one of the preceding claims, characterized in that the radically polymerizable compound b) is a radically polymerizable (meth-)acrylate-containing oligomer selected from the group consisting of aliphatic urethane diacrylates, polyether urethane diacrylates, polybutadiene urethane diacrylates, polyester urethane diacrylates, epoxy acrylates, amino acrylates, and acrylated oligoesters, wherein the radically polymerizable (meth-)acrylate-containing oligomer preferably has a weight average of the molecular weight distribution M w has a density of 500 to 2000 g / mol.

8. Reactively curable adhesive tape system according to one of the preceding claims, characterized in that the counterion to the metal M in the metal complex compound d) is selected from the group consisting of acetylacetonates, fluorinated acetylacetonates, citrates, gluconates, tartrates, stearates, acetates and ethylhexanoates.

9. A reactive curing adhesive tape system according to any one of the preceding claims, characterized in that the metal complex compound d) is selected from the group consisting of iron(III) acetylacetonate, manganese(III) acetylacetonate, copper(II) hexafluoroacetylacetonate, copper(II) ethylhexanoate, and copper(II) acetate.

10. A reactive curing adhesive tape system according to any one of the preceding claims, characterized in that the reducing agent e) is selected from the group consisting of ascorbic acid, N-(diphenylmethylene)glycine ethyl ester, α-acetobutyrolactone, diphenylsilane, 3,5-diethyl-1,2-dihydro-1-phenyl-2-propylpyridine, N-(diphenylmethylene)glycine benzyl ester, and 1,4-dihydro-2,6-dimethyl-3,5-pyridindicarboxylic acid diethyl ester.

11. Reactive curing adhesive tape system according to one of the preceding claims, characterized in that the primer composition is liquid at 23 °C and 1 bar atmospheric pressure.

12. Reactive curable adhesive tape system according to one of the preceding claims, characterized in that the adhesive tape comprises at least one carrier layer.

13. Reactive curable adhesive tape system according to one of claims 1 to 11, characterized in that the adhesive tape is a transfer adhesive tape.

14. Method for producing a bonded composite, in particular for bonding a first substrate X with a second substrate Y, wherein the method comprises at least the following process steps: i.) Provision of a reactive curable adhesive system according to any one of the preceding claims; and ii.) Provision of a first substrate X; and iii.) Application of the primer composition of the reactive curing adhesive system to a surface of the first substrate X; and iv.) Provision of a second substrate Y; and v.) Optionally, applying the primer composition of the reactive curing adhesive system to a surface of the second substrate Y; and vi.) Contacting the primer-treated surface of the first substrate X with a first surface of the adhesive tape of the reactive curing adhesive system; and vii) Contacting the second substrate Y, optionally via its primer-treated surface, with a second surface of the adhesive tape of the reactive curing adhesive system; and viii) . Optionally heating the arrangement comprising the substrate X, the reactive curing adhesive tape system and the substrate Y to a temperature of preferably a maximum of 80 °C.

15. Use of the adhesive tape system according to one of the preceding claims for bonding components in electronic, optical and / or precision mechanical devices, automobiles, medical devices and / or dental devices.

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