EP3390562A1

EP3390562A1 - Self-supporting adhesive body for structural bonds

Info

Publication number: EP3390562A1
Application number: EP16819862.0A
Authority: EP
Inventors: Rui Xu-Rabl; Matthias GÖSSI; Jürgen Finter
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2015-12-17
Filing date: 2016-12-16
Publication date: 2018-10-24
Also published as: US10683442B2; US20180371299A1; WO2017103080A1

Abstract

The invention relates to a composition comprising at least one structural adhesive and at least one chemically crosslinked elastomer based on a silane-functional, non-polar polymer, said elastomer being provided in the form of a penetrating polymer network in the structural adhesive. Self-supporting adhesive bodies, particularly in the form of adhesive tapes, can be produced from such compositions and can be used for structural bonds and to reinforce metal structures.

Description

SELF-WEARING ADHESIVE FOR STRUCTURAL

adhesions

description

Technical area

The invention is in the field of adhesive bodies, in particular in the form of adhesive tapes, which are in particular so dimensionally stable that they are not

Need carrier film. Furthermore, the invention relates to a method for producing such adhesives, which consists of a corresponding

Composition are formed, as well as a method for bonding substrates, in which the adhesive body between the substrates attached and, preferably, with heating, is cured. State of the art

Structural adhesives, in particular epoxy-based, have long been known in the art and are, for example, under the

Trade name "SikaPower ^® " distributed by Sika Schweiz AG. These structural adhesives are usually pasty and are applied from cartridges. However, when applying liquid or liquified adhesives, there is a problem that the applied adhesive may smear and thereby come in contact with areas of the substrate with which contact is not intended. Alternatively, the structural adhesives mentioned can also be processed into adhesive tapes, although they have to be applied to a carrier material (for example in the form of a solid fabric).

In the case of manual application of the adhesives, a reproducible application over large distances requires a relatively large amount of experience in order to avoid smearing or undesired contacting of the splice. Due to the low viscosity of many conventional structural adhesives, it is also necessary to treat them with a relatively large proportion of thixotropic agents. modified so that they do not run off the substrate at elevated temperature before gelling.

The adhesive tapes mentioned above have the advantage that they can be applied by hand. However, the adhesive applied to the substrate is subject to the same requirements in terms of stability as the conventional structural adhesives. As a result, the addition of thixotropic agents is also required here. The need to modify the structural adhesives with thixotropic agents, especially when the required proportion of these agents is due to the

Intrinsic viscosity of the structural adhesive at the application temperature is high, to the detriment of impairing the properties of the

Adhesive. In addition to classic tapes have been some in recent years

Adhesives are described which have shape memory properties. For example, EP 2 570 450 A1 describes shape memory materials based on heat-curing structural adhesives and chemically crosslinked silane-functional elastomers. The chemically cross-linked elastomers used in EP 2 570 450 A1 are, in particular, silane-modified polyethylene or polypropylene glycols. However, these polyglycols have the disadvantage that they are soluble in the cured adhesive and affect its mechanical properties. Against this background, there is a need for structural adhesives which, on the one hand, have a sufficiently high viscosity, even at elevated temperatures, so that the adhesive does not run off or drip off the substrate. For this purpose, the adhesives should, if possible, require only small amounts or no thixotropic agents which impair the adhesive properties of the pure adhesive. Such adhesives could become self-supporting adhesive bodies, in particular in the form of

Adhesive tapes are processed and so would the use of Avoid supporting substrates and associated compatibility problems. The present application addresses this need.

Presentation of the invention

The object of the present invention is therefore to specify a suitable composition for producing a self-supporting adhesive body which can be used for structural bonding, in particular in the form of adhesive tapes, which overcomes the disadvantages of the prior art and can in particular be produced without the use of thixotropic agents. The adhesive body should have properties with those of over

Cartridges to be applied structural adhesives are comparable.

Surprisingly, it was found that this task with

Compositions according to claim 1 can be solved. It has been found, in particular, that self-supporting adhesive bodies, in particular in the form of adhesive tapes, can be produced with the specified compositions, which, in particular with respect to properties such as the impact peel strength and the tensile shear strength, in comparison to

Structural adhesives without the addition of a chemically crosslinked elastomer even improved properties. Further aspects of the invention are the subject of further independent claims. Especially preferred

Embodiments of the invention are the subject of the dependent

Claims. Ways to carry out the invention

The present invention relates in a first aspect a

A composition comprising at least one structural adhesive and at least one chemically crosslinked elastomer based on a silane-functional non-polar polymer. The chemically crosslinked elastomer is preferably present as a penetrating polymer network in the structural adhesive. As a "structural adhesive" is a curable composition containing crosslinkable organic compounds referred to in the

Curing developed a high adhesion (adhesion) and internal strength (cohesion), so that it is suitable for the structural connection of adherends, for example in vehicle construction.

Substance names beginning with "poly", such as polyol or polyisocyanate, refer to substances that formally have two or more in their name

occurring functional groups per molecule.

The term "polymer" on the one hand comprises a collective of chemical

uniform, but differing in terms of degree of polymerization, molecular weight and chain length macromolecules, which was prepared by a polyreaction (polymerization, polyaddition, polycondensation). On the other hand, the term also includes derivatives of such a collective of

Macromolecules from polyreactions, i. Compounds obtained by reactions, such as additions or substitutions, of functional groups on given macromolecules which may be chemically uniform or chemically nonuniform. The term also includes so-called prepolymers, that is, reactive oligomeric pre-adducts whose functional groups are involved in the construction of macromolecules.

The term "silane" denotes compounds which on the one hand at least one, usually two or three, via Si-O bonds, directly to the

Having silicon atom bonded alkoxy groups, on the other hand, at least one via a Si-C bond directly to the silicon atom

having bound organic radical. Such silanes are the

Professional also known as Organoalkoxysilane. Correspondingly, the term "silane group" denotes the silicon-containing group bonded to the silane-bonded organic group via the Si-C bond Organosilanols, ie, organosilicon compounds containing one or more silanol groups (Si-OH groups) and, by subsequent condensation reactions, organosiloxanes, ie, organosilicon compounds containing one or more siloxane groups (Si-O-Si groups).

The term "silane-functional" refers to compounds which have silane groups. "Silane-functional polymers" are accordingly polymers which have at least one silane group. The term "aminosilanes", "mercaptosilanes" and "hydroxysilanes" refers to silanes whose organic radical has an amino group, a mercapto group or a hydroxy group

Aminosilanes designated which have a primary amino group, ie an NH ₂ group which is bonded to an organic radical. As "secondary aminosilanes" aminosilanes are called which are secondary

Have amino group, ie an NH group which is bonded to two organic radicals.

One always refers to the average molecular weight M _n (number average), which is to be determined using appropriate standards by GPC "molecular weight".

The term "pervasive polymer network" is used in accordance with the definition of a "semi-interpenetrating polymer network" (SIPN) according to IUPAC Compendium of Chemical Terminology, 2nd Edition (1997). Accordingly, the SIPN comprises at least one network and at least one linear or

branched polymer, which polymer at least partially penetrates the network. In the composition of the present invention, the elastomer forms the network while the polymer is part of the structural adhesive.

By "chemically crosslinked elastomer" is meant an elastomer which is crosslinked via covalent chemical bonds the crosslinking of a thermoplastic elastomers on physical

Interactions. A chemically crosslinked elastomer differs from a thermoplastic elastomer in that it swells in a suitable solvent but is not dissolved. On the other hand, a thermoplastic elastomer dissolves completely in a suitable solvent.

The presence of a chemically crosslinked elastomer can be determined, for example, on the basis of ASTM D 2765. The structural adhesive is in particular a

thermosetting structural adhesive, which is preferably a

Curing temperature in the range of 120 ° C to 220 ° C, in particular 160 ° C to 200 ° C, having. Is it the structural adhesive is a thermosetting

Structural adhesive, care must be taken during processing of the composition that the composition is not heated enough that the curing process begins. Most preferably, the structural adhesive is a thermosetting epoxy resin composition comprising at least one epoxy resin and at least one epoxy resin curing agent which is activated by elevated temperature.

In particular, it is a one-component epoxy resin composition.

The epoxy resin has, on average, more than one epoxide group per molecule and, in particular, is an epoxy liquid resin or a mixture of an epoxy liquid resin with a solid epoxy resin. The term "epoxy liquid resin" is well known to the epoxy expert and is in the

The glass transition temperature T _g of solid resins is above room temperature (23 ° C). Preferred liquid epoxy resins, which can be used in particular together with a solid epoxy resin, have the formula (I).

Here, the substituents R ¹ and R ^{2 are} again, independently of one another, either H or CH ₃ . Furthermore, the index r stands for a value of 0 to 1. Preferably, r stands for a value of <0.2.

Particularly preferred liquid epoxy resins include diglycidyl ethers of bisphenol A (DGEBA), bisphenol F and bisphenol A F. The term "A / F" refers to a mixture of acetone with

Formaldehyde, which is used as starting material in its preparation. Such liquid epoxy resins are, for example, under the trade names Araldite ^® GY 250, Araldite ^® PY 304, Araldite ^® GY 282 from Huntsman International LLC, or DER ^® 331 or DER ^® 330 from Dow Chemical Company, or under the trade name Epikote ™ 828 or Epikote ™ 862 from Momentive

Specialty ChemicalsBV, commercially available.

Preferred solid epoxy resins have the formula (II).

Here, the substituents R ¹ and R ² are each independently either H or CH _3. Furthermore, the index s stands for a value of> 1,

in particular of> 1, 5, preferably of 2 to 12. Preferred solid epoxy resins have a glass transition temperature T _g in the range of 23 ° C to 95 ° C, in particular from 30 ° C to 80 ° C, preferably from 35 ° C to 75 ° C, on. Such solid epoxy resins are, for example

commercially available from Dow Chemical Company, from Huntsman

International LLC, or Momentive Specialty Chemicals BV.

Depending on the embodiment, the epoxy resin which is used as one of the starting compounds in structural adhesive can also be a solid epoxy resin.

Other suitable epoxy resins are so-called novolacs. These have in particular the following formula (III).

In this case, the radical X is a hydrogen atom or a methyl group. The radical Y is -CH ₂ - or a radical of the formula (IV).

Furthermore, the index z stands for a value from 0 to 7, in particular for a value of> 3.

In particular, these are phenol or cresol novolacs (Y is -CH ₂ -). Epoxy resins are sold under the trade names EPN or ECN and Tactix ^® 556 from Huntsman International, LLC, or through the product series DEN ™ from Dow Chemical Company, are commercially available.

Preferably, the epoxy resin is an epoxy liquid resin of formula (I). In a likewise preferred embodiment, the thermosetting

Epoxy resin composition both at least one liquid epoxy resin of the formula (I) and at least one solid epoxy resin of the formula (II).

The proportion of epoxy resin is preferably 2 to 95 wt .-%,

in particular 5 to 90 wt .-%, preferably 10 to 70 wt .-%, based on the total weight of the structural adhesive. The hardener for epoxy resins is activated by elevated temperature. Preferably, the curing agent for epoxy resins is a compound selected from the group consisting of dicyandiamide, guanamines, guanidines, aminoguanidines and their derivatives; Substituted ureas, in particular 3- (3-chloro-4-methylphenyl) -1, 1-dimethylurea (chlorotoluron), or phenyldimethylureas, in particular p-chlorophenyl-N, N-dimethylurea (monuron), 3-phenyl- 1, 1 -dimethylurea (Fenuron), 3,4-dichlorophenyl-N, N-dimethylurea (diuron), as well as imidazoles and amine complexes.

Particularly preferred as a hardener for epoxy resins is dicyandiamide,

especially in combination with a substituted urea. The advantage of combining dicyandiamide with a substituted urea is the accelerated cure of the composition achieved thereby.

The proportion of the curing agent for epoxy resins is preferably 0.05 to 10 wt .-%, in particular 0.1 to 8 wt .-%, preferably 0.2 to 6 wt .-%, based on the total weight of the structural adhesive. The term "hardener" also includes catalysts and catalytically active compounds In this context, it is clear to the person skilled in the art that when using a catalyst or a catalytically active compound as a hardener for epoxy resins, the proportion of the curing agent in the whole

Structural adhesive is in the lower range of the specified value range.

In addition, the epoxy resin composition may contain at least one

Impact modifier include. By an "impact modifier" is meant addition of an organic polymer to an epoxy resin matrix which, even at low levels, ie, typically between 0.1 and 20% by weight, relative to the structural adhesive causes a significant increase in toughness, and thus in is able to absorb higher impact or impact stress before the matrix breaks or breaks.

Suitable impact modifiers are, in particular, reactive liquid rubbers based on nitrile rubber or derivatives of polyetherpolyol-polyurethanes, core-shell polymers and similar systems known to the person skilled in the art.

Suitable impact modifiers are described as impact modifiers D in the European patent application

EP2182025, the contents of which are hereby incorporated by reference.

The structural adhesive may contain other ingredients, such as

commonly used in structural adhesives.

In particular, the structural adhesive may additionally contain at least one filler. These are preferably mica, talc, kaolin, wollastonite, feldspar, syenite, chlorite, bentonite, montmorillonite, calcium carbonate (precipitated or ground), dolomite, quartz, silicic acids (pyrogenic or precipitated), cristobalite, calcium oxide, aluminum hydroxide, magnesium oxide, Ceramic hollow spheres, glass hollow spheres, organic hollow spheres, glass spheres, color pigments. Filler means both the organically coated and the uncoated commercially available and known in the art forms. Another example is functionalized alumoxanes, as z. As described in US 6,322,890 and the contents of which are hereby incorporated by reference.

The proportion of the filler, if one is included in the structural adhesive, is usually 1 to 60 wt .-%, in particular 5 to 50 wt .-%, and particularly preferably 10 to 35 wt .-%, by weight of the entire structural adhesive.

The structural adhesive may also contain thixotropic agents, such as

for example pyrogenic silicas or nanoclays,

Toughness modifiers, reactive diluents and other ingredients known to those skilled in the art, but the addition of particular thixotropic agents is not required. As a result, the

composition according to the invention preferably no thixotropic agent. Most preferably, the structural adhesive is a one-part, thermosetting epoxy resin composition.

The proportion of the structural adhesive is preferably 50 to 85% by weight, especially 60 to 85% by weight, and most preferably about 65 to 80% by weight, based on the total composition.

In addition to the structural adhesive, the composition according to the invention has a chemically crosslinked elastomer based on a silane-functional, nonpolar polymer. The non-polarity refers to the backbone or to the base polymer of the silane-functional polymer prior to its functionalization with silane groups. The non-polarity of the silane-functional polymer is essential for the present invention, as it is incompatible with the cured structural adhesive and it should thereby come to a phase separation in the curing of the structural adhesive. Only in this way can suitable systems be formulated as self-supporting adhesive bodies, which have sufficient mechanical strengths. That it comes in a specific case to a phase separation, can be easily determined by DMA (Dynamic Mechanical Analysis).

Ideally, the silane-functional nonpolar polymer is dissolved in the structural adhesive before curing and largely homogeneously distributed. If the structural adhesive is an epoxy resin composition, curing of the epoxy resin results in secondary hydroxyl groups which are incompatible with the non-polar backbone of the silane-functional nonpolar polymer.

Silane-functional nonpolar polymers typically include silane-functional hydrocarbon polymers, typically one

Liquid rubber (i.e., a rubbery polymer having a liquid consistency at 23 ° C) within the backbone of the base polymer

Exception of ether functions does not contain functional groups with heteroatoms. Accordingly, polyesters are not a nonpolar polymer in the sense of the present invention. Suitable silane-functional non-polar polymers are, for example, those based on saturated or unsaturated polymers and polyethers. With regard to polyethers, however, it should be borne in mind that only those in the context of the present invention should be considered as "non-polar polymers" in which the ratio of the

Carbon atoms to the oxygen atoms of the monomers on average greater than 3: 1, in particular polybutylene glycols or poly (tetramethylene) glycols or polyoxyalkylene generally higher molecular weight alkylene groups.

Polyethylene glycols or polypropylene glycols are within the scope of

present invention as non-polar and thus silane-functional

Polyethylene glycols or polypropylene glycols not as a silane-functional nonpolar polymer. The same applies to copolymers with polyethylene oxide and polypropylene oxide units. Particularly suitable liquid rubbers based on unsaturated

Polymers are, for example, those based on polyisoprene, polybutadiene and butadiene / acrylonitrile copolymers. The liquid rubbers mentioned have in particular a molecular weight in the range from 1000 to 10000 g / mol, preferably about 1500 to 5000 g / mol, particularly preferably about 2000 to 5000 g / mol. Preferably, the liquid rubbers have an equivalent weight (i.e., an equivalent weight)

functional group weight relative) in the range of about 200 to 1000 g / Eq, in particular about 300 to 1500 g / Eq, on.

The chemically crosslinked elastomer is preferably present as a penetrating polymer network in the structural adhesive. To this end, the chemically crosslinked elastomer based on a silane-functional non-polar polymer can be incorporated into the composition by mixing a silane-functional polymer with the structural adhesive and then crosslinking in the mixture to form a penetrating polymer network in the structural adhesive.

The proportion of the chemically crosslinked elastomer based on a silane-functional non-polar polymer is preferably from 15 to 50% by weight, in particular from 15 to 40% by weight, and particularly preferably from 20 to 35% by weight, based in each case on the total Composition.

As a silane-functional non-polar polymer are particularly suitable

Reaction products of the aforementioned nonpolar polymers with silanes having silane groups of the formula -R ⁴ -Si (OR ¹ ) (OR ² ) (OR ³ ) or -R ⁴ -SiR ¹ (OR ² ) (OR ³ ). The radicals R ¹ , R ² and R ^{3 are} alkyl groups,

in particular having 1 to 8 C atoms which optionally contain oxygen atoms in the form of ether functions. The radicals R ¹ , R ² and R ³ may also be the same or different. Particularly suitable radicals R ¹ , R ² and R ³ are methyl or ethyl groups and -OC ₂ H ₄ OC ₂ H ₄ OCH ₃ groups. More preferably, the silane groups are -R ⁴ -Si (OEt) ₃ or -R ⁴ -Si (OMe) x (OC ₂ H ₄ OC ₂ H ₄ OCH ₃ ) 3-x, where x is 0 to 2 can accept. The radical R ⁴ is a linear or branched divalent hydrocarbon radical having 1 to 12 C atoms, which optionally cyclic and / or aromatic moieties, and optionally one or more

Heteroatoms, in particular one or more nitrogen or oxygen atoms having. In particular, R ^{4 is} a linear or branched alkylene group having 1 to 6 C atoms, preferably methylene or 2-hydroxy-1, 3-propylene.

In a first embodiment, the silane-functional nonpolar polymer is a silane-functional polymer P1 obtainable by reacting a silane having at least one epoxy-reactive group with a nonpolar polymer having terminal

Having epoxy groups. This reaction is preferred in one

stoichiometric ratio of the epoxy groups reactive groups to the epoxy groups of about 1: 1 or a slight excess of epoxy groups reactive groups carried out so that the resulting silane-functional polymer P1 is completely free of epoxy groups.

As a nonpolar polymer having terminal epoxy groups, functionalized butyl rubbers (ETBN) are suitable in the context of the embodiment described here, in particular with epoxides, as described, for example, under the trade names Hypro ™ by Emerald Performance

Materials are available.

The silane, which is at least one opposite epoxy groups

Group is, in particular, a mercaptosilane, a hydroxysilane or or an aminosilane, preferably an aminosilane.

Examples of suitable aminosilanes are primary aminosilanes such as 3-aminopropyltrimethoxysilane, 3-aminopropyldimethoxymethylsilane; secondary Aminosilanes such as N-butyl-3-aminopropyltrinnethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane; Michael-like addition products of primary aminosilanes such as 3-aminopropyltrimethoxysilane or 3-aminopropyldimethoxymethylsilane to Michael acceptors such as acrylonitrile, (meth) acrylic acid esters, (meth) acrylic acid amides, maleic and fumaric diesters, citraconic diesters and itaconic diesters, for example N- (3-trimethoxysilyl-propyl) -amino-succinic acid dimethyl and diethyl ester; and analogs of said aminosilanes with ethoxy, isopropoxy or

Methyloxyethoxyethoxy groups (-O-C2H-O-C2H -OCH ₃ ) in place of

Methoxy groups on the silicon.

In a second embodiment, the silane functional nonpolar polymer is a silane functional polymer P2 obtainable by the reaction of an epoxysilane with a nonpolar polymer having terminal epoxide-reactive functional groups.

Epoxysilanes suitable for such reactions are not subject to any limitations except for the requirement that they contain an epoxy group and a silane group linked together via a linker. However, glycidoxypropylsilanes, as typically made from glycidol and 3-chloropropylsilanes, have been found to be particularly useful because of low commercial availability.

Particularly suitable Glycidoxypropylsilane are 3-glycidoxypropyltrimethoxysilane (eg available as Silquest ^® A-187 of

Momentive), 3-glycidoxypropyltriethoxysilane (obtainable, for example available as CoatOSil ^® 2287 from Momentive), or transesterification products of 3-glycidoxypropyltrimethoxysilane (with diethylene glycol monomethyl ether for example as Dynasylan ^® GLYEO from Evonik), 3-glycidoxypropylmethyldiethoxysilane (eg

available as Araldite ^® DY 1158 available from Huntsman).

Nonpolar polymers which have terminal epoxide-reactive functional groups can be used in particular nonpolar polymers having terminal hydroxyl, amino, mercapto or carboxy functions, the use of carboxy functions being relatively unfavorable and therefore less preferred than the other variants because of the high reaction temperatures required for reaction with epoxides. Thus, it has been observed that over heating the reaction mixture leads to a reaction of the silane groups with one another and thus to premature crosslinking (gelling) of the system. Therefore, nonpolar polymers with terminal amino and hydroxyl functions are particularly suitable. Particularly suitable non-polar polymers are amino-terminated butadiene / acrylonitrile copolymers (ATBN) and hydroxy-terminated butadiene / acrylonitrile copolymers (OH-HTBN). An amino-terminated butadiene / acrylonitrile copolymer is available, for example, under the tradename Hypro ™ 1300X16 ATBN from Emerald Performance Materials.

Particularly suitable non-polar polymers, the terminal to epoxides have reactive functional groups and are based on polyethers, amino-terminated poly (tetramethylene) glycols are, for example Jeffann ine THF ^® 170 from Huntsman.

In a third embodiment, the silane-functional non-polar polymer is a silane-functional polymer P3 obtainable by reacting a silane having at least one isocyanate-reactive group with a non-polar polymer having terminal

Has isocyanate groups. This reaction is preferably also carried out in a stoichiometric ratio of the isocyanate-reactive groups to the isocyanate groups of about 1: 1 and a slight excess of isocyanate-reactive groups, so that the resulting silane-functional polymer P3 is completely free of isocyanate groups. Suitable silanes which have at least one isocyanate-reactive group are the same compounds which have been described above for the reaction with epoxy-terminated nonpolar polymers have been mentioned since amino, hydroxy and mercapto functions react with both epoxy groups and isocyanate groups.

Suitable nonpolar polymers containing isocyanate groups for preparing a silane-functional polymer P3 are, in particular, nonpolar polymers obtainable by reacting non-polar polyols or polyamines according to the above provisos with at least one polyisocyanate, in particular a diisocyanate. The preparation of these non-polar polymers can be carried out by the polyol and the polyisocyanate by conventional methods, for example at temperatures of 50 ° C to 100 ° C,

optionally with the concomitant use of suitable catalysts, are reacted, wherein the polyisocyanate is metered so that its

Isocyanate groups in relation to the hydroxyl groups or amine groups of the polyol or polyamine in the stoichiometric excess of about 2: 1 or more are present. Through these procedures can

be ensured that the non-polar polymer is terminal with

Polyisocyanates is functionalized and it does not come to the formation of long-chain polyurethane polymers. Commercially available polyisocyanates, in particular diisocyanates, can be used as polyisocyanates. For example, suitable diisocyanates are 1, 6-hexamethylene diisocyanate (HDI), 2-methylpentamethylene-1,5-diisocyanate, 2,2,4- and 2,4,4-trimethyl-1,6-hexamethylene diisocyanate (TMDI), 1, 12 -Dodeca- methylene diisocyanate, lysine and Lysinesterdiisocyanat, cyclohexane-1, 3-diisocyanate, cyclohexane-1, 4-diisocyanate, 1 -lsocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate or IPDI), Perhydro -2,4'-diphenylmethane diisocyanate and perhydro-4,4'-diphenylmethane diisocyanate, 1,4-diisocyanato-2,2,6-trimethylcyclohexane (TMCDI), 1, 3 and 1, 4-bis (isocyanato-methyl) -cyclohexane, m- and p-xylylene diisocyanate (m- and p-XDI), m- and p-tetramethyl-1,3-xylylene diisocyanate, m- and p-tetramethyl-1,4-xylylene diisocyanate, bis (1 -lsocyanato-1-methylethyl) -naphthalene, 2,4- and 2,6-toluene diisocyanate (TDI), 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI), 1, 3 and 1, 4-phenylenediisocyanate, 2,3,5,6-tetramethyl-1, 4- diisocyanatobenzene, naphthalene-1, 5-diisocyanate (NDI), 3,3'-dimethyl-4,4'-diisocyanatodiphenyl (TODI), oligomers and polymers of the aforementioned polyisocyanates, as well as any mixtures of the aforementioned

Polyisocyanates.

Particularly suitable polyisocyanates are HDI, TMDI, IPDI, TDI and MDI, in particular IPDI.

Preferably, it is within the scope of the described third

Embodiment of the non-polar polymer to a butyl rubber, in particular based on polybutadiene or a butadiene / acrylonitrile copolymer. Such rubbers may in particular be functionalized with amino groups, hydroxy groups or mercapto groups. Alternatively, a polyether, preferably a hydroxy-terminated polyether, and most preferably a hydroxy-terminated poly (tetramethylene) glycol may be used as the non-polar polymer in the third embodiment. A commercially available poly (tetramethylene) glycol, for example PolyTHF ^® 2000 from BASF. In a fourth embodiment, the silane-functional non-polar polymer is a silane-functional polymer P4 which is obtainable by reacting an isocyanatosilane with a non-polar polymer having isocyanate-reactive functional end groups, in particular

Hydroxyl groups, mercapto groups and / or amino groups. This reaction takes place in the stoichiometric ratio of the isocyanate groups to the isocyanate-reactive functional end groups of 1: 1 or with a slight excess of isocyanate-reactive functional end groups, for example at temperatures of 20 ° C to 100 ° C, optionally with concomitant use of catalysts.

Suitable isocyanatosilane compounds of the formulas (V) or (VI). OCN R ⁴ Si (OR ¹ ) (OR ² ) (OR ³ ) (V) OCN R ⁴ SiR ¹ (OR ² ) (OR ³ ) (VI) wherein R ¹ to R ^{4 have} already been described above.

Examples of suitable isocyanatosilanes of the formulas (V) or (VI) are isocyanatomethyltrimethoxysilane, isocyanatomethyldimethoxymethylsilane 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyldimethoxymethylsilane, and their analogs having ethoxy or isopropoxy groups instead of the methoxy groups on the silicon.

The nonpolar polymer preferably has amino groups as isocyanate-reactive functional end groups.

Suitable amino-containing non-polar polymers are, in particular, the abovementioned polymers based on poly (tetramethylene) glycol, e.g.

Jeffamine ^® THF-170 from Huntsman.

In addition, the silane-functional non-polar polymer can be prepared by a hydrosilylation reaction of nonpolar polymers and in particular

Polyethers are prepared according to the above specifications, for example, with vinyl or allyl-terminated poly (tetramethylene) glycols.

In contrast, it was not possible to have a silane-functional nonpolar

Polymer obtained by reacting carboxy-functional non-polar polymers with aminosilanes.

The composition according to the invention is particularly preferably obtainable by

Reaction of a silane with a non-polar polymer, wherein either the silane or the nonpolar polymer has reactive groups with respect to epoxides, and the other component has epoxide groups; or reacting a silane with a nonpolar polymer, wherein either the silane or the nonpolar polymer faces Isocyanate-reactive groups, and the other

Component isocyanate groups;

- Vernenness of the resulting silane-functional non-polar polymer with the structural adhesive; and

- Storage of the resulting composition under conditions under which crosslinks the silane-functional non-polar polymer with water.

The described procedure has the advantage over the preparation of the silane-functional nonpolar polymer in the structural adhesive in situ that the formation of a penetrating polymer network can be more easily ensured.

In the preparation of the composition according to the invention, the structural adhesive is mixed with the silane-functional nonpolar polymer, preferably giving a homogeneous mixture. Includes the

Structural adhesive as an epoxy resin epoxy resin, the mixing is carried out at a temperature above the glass transition temperature Tg of

Epoxidfestharzes. Is the structural adhesive a thermosetting one?

Epoxy resin composition, this may be mixed with the silane-functional non-polar polymer prior to the addition of the curing agent for epoxy resins. As a result, the temperature can be adjusted during mixing to or even beyond the curing temperature of the thermosetting epoxy resin composition, without causing the curing of the

Structural adhesive comes. At higher temperatures, more efficient mixing is usually achieved.

After a particularly homogeneous mixture was obtained, the crosslinking of the silane-functional non-polar polymer takes place. The elastomer formed in this way is in particular a penetrating polymer network

Structural adhesive before. The cross-linking of the silane-functional nonpolar

Polymer proceeds by reaction of the contained silane groups with water. The water required for crosslinking is present in particular in the form of atmospheric moisture, which passes through diffusion processes in the composition. For the crosslinking of the silane-functional nonpolar polymer with water, the composition may contain a catalyst. such

Catalysts are, in particular, organotin compounds, for example dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetylacetonate and dioctyltin diacetylacetonate; Titanates and zirconates, for example

Tetraisobutoxy titanate and diisobutoxy titanium bis (ethylacetoacetate);

Nitrogen compounds, in particular tertiary amines, for example N, N-dimethylbenzylamine, Ν, Ν-dimethylcyclohexylamine and 1, 4-diazabicyclo [2.2.2] octane, and amidines and guanidines, for example 1, 8-diazabicyclo [5.4.0] undec-7 -en and 1,1,3,3-tetramethylguanidine; such as

Mixtures of the catalysts mentioned.

In the context of the investigations carried out, it has been found that the addition of an aminosilane as crosslinking assistant for the crosslinking of the silane-functional non-polar polymer to improve the

Tensile shear strength and impact peel strength can contribute. It is therefore preferred in the context of the present invention, if the

Composition of the invention an aminosilane, preferably a

Aminoalkyltrialkoxysilane is added. Suitable aminosilanes include the aforementioned aminosilanes. A particularly suitable aminosilane is N- (2-aminoethyl) -3-aminopropyltrimethoxysilane

A-1 is available from Momentive for example, under the trade name Silquest ^® 120th

The said aminosilanes are useful in an amount of 0.1 to 1, 5 wt .-%, preferably 0.2 to 1 wt .-%, based on the total weight of the composition to include in this. In a further aspect, the present invention relates to a process for producing an adhesive body from a composition as described above comprising the steps of: reacting a silane with a nonpolar polymer, wherein either the silane or the nonpolar polymer is resistant to epoxides having reactive groups, and the other component has epoxide groups; or reacting a silane with a non-polar polymer, wherein either the silane or the nonpolar polymer has isocyanate-reactive groups, and the other one

Component isocyanate groups;

- mixing the obtained silane-functional non-polar polymer with the structural adhesive;

- shaping of the resulting mixture, optionally on one

Carrier or substrate; and

- Storage of the molded mixture under conditions under which crosslinks the silane-functional non-polar polymer with water.

In a preferred embodiment of the method, the shaping takes place in such a way that the adhesive body receives a planar shape, in particular a band or a strip, and thus represents an adhesive tape.

The shaping preferably takes place by means of glazing.

In a preferred embodiment of the process, the crosslinking of the silane-functional nonpolar polymer takes place via the reaction of

Silane groups with water in the form of humidity.

Another aspect of the present invention relates to adhesives made from a composition as described above. Such adhesive bodies are preferably in the form of a band or strip and preferably have a thickness in the range of 0.1 to 5 mm, in particular 0.5 to 3 mm. Such adhesives are in particular self-supporting and in particular constitute adhesive tapes. The adhesives produced from the process according to the invention can be used, in particular, for structural bonding and for reinforcing

Metal structures are used, especially in vehicle construction.

Another aspect of the present invention finally concerns a

A method of joining two substrates comprising the steps

Applying an adhesive body, as described above, to a first substrate,

Contacting the adhesive body on the first substrate with a second substrate, and

- Curing the composition of the adhesive body, preferably by

Heat. If appropriate, the method of bonding may also be carried out omitting the first step in the event that the shaping of the adhesive body has been carried out according to the described method for producing the adhesive body on a first substrate. The first substrate is preferably a metal substrate, in particular electrolytically galvanized, hot-dip galvanized, and subsequently phosphated steel sheet, oiled steel sheet and various,

optionally surface-treated aluminum alloys, or a thermoplastic substrate, for example a polyamide, polyester,

Polyurethane, polyolefin, polysulfone, polyvinyl chloride, in particular a

High temperature resistant thermoplastic substrate such as a polyamide, poly (butylene) terephthalate, polyphenylene ether, polysulfone or polyethersulfone, preferably a polyamide, in particular PA 6, PA 6,6, PA 1, PA 12, PA 6,10, PA 6,12 or a mixture of them.

The second substrate is preferably likewise a metal substrate, in particular electrolytically galvanized, hot-dip galvanized, and subsequently phosphated steel sheet, oiled steel sheet as well

various, optionally surface-treated, aluminum alloys.

Examples

In the following, exemplary embodiments are listed which are intended to explain the described invention in more detail. Of course, the invention is not limited to these described embodiments. Used commercial substances

Hypro ™ 1300X16 ATBN amine-terminated butadiene-acrylonitrile copolymer; Mw = about 3600 g / mol;

Equivalent weight 900 g / eq, from Emerald Performance Materials

Jeffamine ^® THF-170 polyetheramine based

glycol of poly (tetramethylene); Mw = about 1700 g / mol; Equivalent weight 380 g / eq, from

Huntsman

Dynasilan ^® GLYEO 3- glycidoxypropyltriethoxysilane, Evonik

Araldite ^® DY 1158 transesterification of 3- glycidoxy propyltrimethoxysilane with

diethylene glycol monomethyl ether; Mw = about 500, from Huntsman

MS Polymer ™ S303H trimethoxysilane-terminated polypropylene glycol having an average functionality of 2.3 and a Mw of about 12000 g / mol, from Kaneka

Silyl ™ SAX400 trimethoxysilane-terminated polypropylene glycol having an average functionality of 3 and a Mw of about 24,000 g / mol, from Kaneka

PolyTHF ^® 2000 poly (tetramethylene) glycol having a Mw of about

2000 g / mol, from BASF

Vestanate ^® IPDI isophorone, Evonik

DBTDL dibutyltin dilaurate, from Fluka

Silquest ^® A-1120 N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, Momentive Araldite ^® GY 250 liquid epoxy resin based on DGEBA, Mw = 375 g / mol, from Huntsman

Dicyandiamide from Evonik

Tyzor ^® Ibay bis (ethyl acetoacetate) diisobutoxy-titanium (IV) of

Village Ketal

test method

Impact peel strength was determined using ISO 1 1343 with measurements taken at 23 ° C.

Tensile shear strength was determined from EN1465 on a 2 mm thick 5 x 25 mm strip attached to an acetone-cleaned HDG (H380) steel strip of 0.8 mm thickness.

The gel content was determined according to ASTM 2765 according to Method A. To this end, two containers of 100 mesh polyamide fabric, each containing 0.3 g of ground sample material, were stored in an excess of methyl ethyl ketone (MEK) for at least 40 hours at room temperature. Subsequently, the containers were washed with MEK and dried for at least 5 hours at room temperature. Thereafter, further drying was carried out in vacuo at 50 ° C for at least 18 hours. The non-soluble weight fraction remaining in the container corresponds to the gel content or the gel fraction.

Preparation of Inventive Compositions and Adhesive Tapes Obtained Therefrom

According to the amounts given in Table 1, a

Liquid rubber and an epoxy silane mixed in a container and heated to a temperature of 80 ° C for 1 hour. The course of the reaction was checked by means of the NIR absorbance of the epoxypeak at about 4522 cm ^-1 , which showed that after a reaction time of 1 hour, the epoxy groups in the Were essentially abreacted. To the thus-obtained silane-functional non-polar polymer, after heating, the epoxy liquid resin was added and mixed by means of a centrifugal mixer for 2 minutes at 3500 rpm. Subsequently, the hardener for epoxy resins (dicyandiamide) was added and mixed in as well. Adhesive tapes were made with the finished blends by placing them in a thickness of 5 mm on PTFE molds and 0.3 mm thick directly on the steel substrate of the test specimens and leaving them at 23 ° C for 7 days at room temperature in air, wherein the silane groups crosslinked with moisture. The adhesive tape thus prepared was tested for gel content.

Furthermore, the tape was in a convection oven first during 2

Hardened at 80 ° C and then for 1 .5 hours at 180 ° C and tested for tensile shear strength and impact peel strength. As comparative examples, as the silane-functional polymer, two different silane-terminated polyethers based on polypropylene glycol (MS Polymer ™ S303H and Silyl ™ SAX400) were used in combination with a catalyst for silane crosslinking.

The compositions of the individual formulations and the mechanical properties are given in the following Table 1.

Table 1

In a further series of experiments, a silane-functional non-polar polymer in the form of a silane-functional was first

Poly (tetramethylene ether) glycol ( "S-PTMEG") was prepared. To this end a hydroxysilane by reaction of 3-aminopropyltriethoxysilane with L-lactide was first prepared addition, an isocyanate-functional poly (tetramethylene ether) glycol by reacting PolyTHF ^® 2000 with Vestanat was. ^® IPDI in the ratio 1:. 2 the hydroxysilane was then reacted at 80 ° C with the isocyanate-functional poly (tetramethylene ether) glycol with an OH / NCO ratio of 1 .1 / 1 to S- PTMEG.

The S-PTMEG was in the following with the aid of a centrifugal M ischers with liquid epoxy resin, hardener, catalyst for the silane crosslinking (Tyzor ^® ibay) and optionally aminosilane (Silquest ^® A-1 120) are mixed and further driven as described for Example. 1 The exact compositions of the materials studied and the particular physical properties are given in Table 2 below.

Table 2

From the results of the investigations it can be seen that the addition of Silquest® A-1 120 can further improve the tensile shear strength and the peel strength by about 20%. In addition, arise in the

Examples with higher proportion of epoxy liquid resin slightly better

Tensile shear strengths.

Claims

claims

Comprising composition

- At least one structural adhesive, as well

- At least one chemically crosslinked elastomer based on a silane-functional non-polar polymer.

A composition according to claim 1, characterized in that the non-polar polymer is selected from unsaturated polymers and polyethers in which the ratio of the carbon atoms to the oxygen atoms of the monomers in the polyether is on average greater than 3: 1.

Composition according to Claim 2, characterized in that the unsaturated polymers are selected from polyisoprene,

Polybutadiene and butadiene / acrylonitrile copolymers.

Composition according to one of claims 1 to 3, characterized in that the chemically crosslinked elastomer is present as a penetrating polymer network in the structural adhesive.

Composition according to any one of the preceding claims, characterized in that the silane-functional polymer

Silane groups having the formula -R ⁴ -Si (OR ¹ ) (OR ² ) (OR ³ ) or - R ⁴ -SiR ¹ (OR ² ) (OR ³ ), wherein R ¹ , R ² and R ^{3 are the} same or different and alkyl groups which may contain ether functions, and R ^{4 is} a linear or branched divalent hydrocarbon radical having 1 to 12 carbon atoms and optionally one or more heteroatoms.

Composition according to any one of the preceding claims, characterized in that the structural adhesive comprises a thermosetting epoxy resin composition comprising at least one epoxy resin and at least one epoxy resin hardener activated by elevated temperature.

Composition according to one of the preceding claims, characterized in that the proportion of structural adhesive 50 to 85 wt .-%, preferably 70 to 85 wt .-%, and the proportion of the chemically crosslinked elastomer based on a silane-functional non-polar polymer 15 to 50 Wt .-%, preferably 15 to 30 wt .-% is.

Composition according to one of the preceding claims, characterized in that the chemically crosslinked elastomer with the concomitant use of an aminosilane, in particular a

Aminoalkyltrialkoxysilans, as a crosslinking aid was obtained.

Process for producing an adhesive body from a

A composition according to any one of the preceding claims, comprising the steps

- Implementation of a silane with a nonpolar polymer, wherein

either the silane or the nonpolar polymer has epoxide-reactive groups, and the other of the constituents has epoxide groups; or reacting a silane with a nonpolar polymer, wherein either the silane or the nonpolar polymer has isocyanate-reactive groups and the other constituent has isocyanate groups;

- shaping the resulting mixture, optionally on a support or substrate; and

10. The method according to claim 9, characterized in that the

Crosslinking of the silane-functional non-polar polymer with water takes place in the form of atmospheric moisture.

1 1. Adhesive body obtained from a method according to claim 9 or 10. 12. Adhesive body according to claim 1 1, characterized in that it has a thickness in the range of 0.1 to 5 mm, in particular 0.5 to 3 mm.

13. Use of an adhesive body according to any one of claims 1 1 or 12 for connecting two substrates. 14. Use according to claim 13 comprising the steps:

Applying the adhesive body to a first substrate,

- Curing of the adhesive preferably by heating.