EP2513243A2

EP2513243A2 - Crimping fold bond

Info

Publication number: EP2513243A2
Application number: EP10795366A
Authority: EP
Inventors: Michael Gutgsell; Jan Olaf Schulenburg
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2009-12-18
Filing date: 2010-12-17
Publication date: 2012-10-24
Also published as: WO2011073422A2; WO2011073422A3; EP2336262A1

Abstract

The present invention relates to the use of a heat-curable epoxy composition containing at least one epoxy resin A comprising on average more than one epoxy group per molecule; at least one curing agent B for epoxy resins that is activated by an elevated temperature; and metal particles having an average particle size of 50 to 3000 μm as the adhesive in crimping fold bonds. The use is characterized by efficient heat input into the adhesive of the crimping fold bond.

Description

BÖRDELFALZVERKLEBUNG

Technical area

The invention relates to the field of Bördelfalzverklebungen.

State of the art

Edge banding bonds have long been used in industrial production. It is known means of transport, such as doors,

Trunk bonnets, rear panel flaps produce engine compartment hoods and the like from an outer panel and an inner panel by means of hinge connection. In order to ensure a fixation of the fold in this case an adhesive is used, which connects the inner panel with the outer panel. In order to be able to expose mechanical stresses as quickly as possible to these means of transport parts, adhesives for edgebanding bonds must have the shortest possible crosslinking times. For example, as an adhesive

thermosetting adhesives use, wherein the heat input in industrial manufacturing typically indirectly via the heating of the

Transport center part is done. The patent application EP 1935955 (A1) describes such an adhesive which, however, under certain circumstances has too slow a cure. A fast and efficient crosslinking of the adhesives is desirable in industrial manufacturing for time and cost reasons.

Presentation of the invention

Object of the present invention is therefore, adhesives for

To provide Bördelfalzverklebungen available, which are characterized by a short curing time.

Surprisingly, it has been found that this object can be achieved by the use according to claim 1. This is made possible, in particular, by using a thermosetting epoxy composition containing an average of metallic particles

Particle size of 50 - 3000 μιτι having the heat energy input from the transport center part in the adhesive of Bördelfalzverklebung to

accelerate.

Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims.

Modes for Carrying Out the Invention The present invention in a first aspect relates to the use of a thermosetting epoxy composition

- At least one epoxy resin A with an average of more than one

Epoxide group per molecule;

- At least one hardener B for epoxy resins, which increased by

Temperature is activated; such as

metallic particles with an average particle size of 50-3000 μm

as an adhesive in edging seams. The thermosetting epoxy composition contains at least one

Epoxy resin A with an average of more than one epoxide group per molecule. The epoxide group is preferably present as a glycidyl ether group. The

Epoxy resin A having on average more than one epoxide group per molecule is preferably an epoxy liquid resin or a solid epoxy resin. The term "solid epoxy resin" is well known to the person skilled in the art and is used in contrast to "liquid epoxy resins". The glass transition temperature of solid resins is above room temperature, i. they join

Crush room temperature to pourable powders.

Preferred solid epoxy resins have the formula (X)

Here, the substituents R 'and R "independently of one another are either H or CH ₃ .

Furthermore, the index s stands for a value of> 1 .5, in particular from 2 to 12.

Such solid epoxy resins are commercially available, for example, from Dow or Huntsman or Hexion.

Compounds of formula (X) with an index s between 1 and 1 .5 are referred to by the skilled person as semisolid epoxy resins. For the present invention, they are also considered as solid resins.

However, preferred are epoxy resins in the narrower sense, i. where the index s has a value of> 1 .5.

Preferred liquid epoxy resins have the formula (XI)

Here, the substituents R '"and R""independently of one another are either H or CH _3. Furthermore, the index r stands for a value from 0 to 1. Preferably, r stands for a value of less than 0.2.

It is thus preferably 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 becomes). Examples of such liquid resins are Araldite® GY 250, Araldite® PY 304, Araldite® GY 282 (Huntsman) or DER ™ 331 or DER ™ 330 (Dow) or Epikote 828 (Hexion).

Preferably, the epoxy resin A is an epoxy liquid resin of formula (XI). In a more preferred embodiment, the thermosetting epoxy composition contains both at least one epoxy liquid resin of formula (XI) and at least one solid epoxy resin of formula (X).

The proportion of epoxy resin A is preferably 5 to 85% by weight, in particular 10 to 70% by weight, preferably 10 to 60% by weight, based on the weight of the thermosetting epoxy composition.

The thermosetting epoxy composition further contains at least one curing agent B for epoxy resins, which is activated by elevated temperature. It is preferably a curing agent which is selected from the group consisting of dicyandiamide, guanamines, guanidines, aminoguanidines and derivatives thereof. Also possible are accelerating effective curing agents, such as substituted ureas, such as, for example, 3-chloro-4-methylphenylurea (chlorotoluron), or phenyldimethylureas, in particular p-chlorophenyl-N, N-dimethylurea (monuron), 3-phenyl-1 , 1-dimethylurea (fenuron) or 3,4-dichlorophenyl-N, N-dimethylurea (diuron) or non-aromatic-substituted ureas.

The substituted ureas are preferably non-aromatic-substituted ureas, in particular aliphatically-substituted ureas, particularly preferably N, N-dimethylurea (= 1,1-dimethylurea), N, N'-dimethylurea (= 1, 3). Dimethylurea), Ν ', Ν'-dimethyl-N-butylurea (= 3-butyl-1, 1-dimethylurea) and Ν, Ν, Ν', Ν'-tetramethylurea (= 1, 1, 3,3-tetramethylurea) ,

Hardener B is preferably a hardener which is selected from the group consisting of dicyandiamide, guanamine, guanidines, aminoguanidines, substituted ureas, imidazoles and amine complexes, and derivatives thereof.

Particularly preferred as hardener B, in conjunction with

Dicyandiamide, N, N-dimethylurea (= 1,1-dimethylurea), Ν, Ν'- Dimethylurea (= 1, 3-dimethylurea), N ', N'-dimethyl-N-butylurea (= 3-butyl-1, 1-dimethylurea) and Ν, Ν, Ν', Ν'-tetramethylurea (= 1, 1 , 3,3-tetramethylurea). Advantageously, the total amount of hardener B is 0.5 to 12% by weight.

%, preferably 1-8% by weight, based on the weight of

thermosetting epoxy composition.

The thermosetting epoxy composition further contains metallic particles having an average particle size of 50 - 3000 μηη.

The term "metallic particles" in the present document means particles containing metal or metal alloys.

Preferably, the metallic particles have an average particle size of 100 to 1000 μιτι, in particular from 200 to 400 μιτι on.

Preferably, the metallic particles have such

Distribution of the particle size to that more than 70, preferably more than 80% of the metallic particles not more than 50%, preferably not more than 30% differ from the average particle size.

A typical measurement method for determining the particle size is a determination based on a sieve analysis according to DIN 66165.

It is also advantageous if the composition of the metallic particles has a hardness measured according to the hardness test method Vickers DIN ISO 6507: 2005 of less than 120 HV 1, preferably less than 50 HV 1, particularly preferably less than 30 HV 1.

Typical values for the hardness HV 1 for metals are, for example: aluminum 17 HV 1, copper 37 HV 1, tin 6 HV 1, zinc 40 HV 1, chrome 100 HV 1, iron 60 HV 1, nickel 64 HV 1, and lead 5 HV 1.

This is especially true when using the thermosetting

Epoxy composition as an adhesive for Bördelfalzverklebungen advantageous. Since adhesives are pressed in crimp seam bonds, the metallic particles are due to a previously mentioned hardness with the applied pressing force to the intended layer thickness for the adhesive layer brought. As the metallic particles are preferably larger

Diameter than the adhesive layer thickness, leads to a hardness mentioned that the metallic particles are on both sides in contact with the outer sheet, respectively the inner sheet after pressing.

Thus, it is of great advantage if the metallic particles are pressed under the applied pressure, respectively, are pressed to the intended adhesive layer thickness, so the metallic particles do not withstand the pressure during compression and plastically deform.

It is also advantageous if a significant proportion of the surface of the metallic particles in the pressed state with the outer panel, resp. the inner panel, in contact. A significant proportion of the surface is to be understood as meaning more than 15%, preferably 25-80%, in particular 50-75%, of the surface of the metallic particles. The skilled person is clear that between metallic particles in the pressed state and inner plate and / or outer plate may be a very thin layer of

Adhesive binder can be located.

The composition of the metallic particles preferably has a thermal conductivity of greater than 10 W / (m-K), preferably greater than 50 W / (m-K), particularly preferably greater than 100 W / (m-K).

Since edgeband bonds are typically at least partially cured by induction heating, a thermal conductivity greater than 10 W / (m-K) contributes to efficient thermal energy input.

Typical thermal conductivities for metals are, for example: aluminum 200 W / (mK), copper 380 W / (mK), tin 65 W / (mK), zinc 1 10 W / (mK), chromium 95 W / (mK), iron 80 W / (mK), nickel 85 W / (mK), and lead 35 W / (mK).

The term "thermal conductivity" is understood to mean the thermal conductivity at 23 ° C.

Preferably, the composition of the metallic particles contains a metal selected from the list consisting of aluminum, copper, tin, zinc, chromium, iron, nickel and lead. Particularly preferably, the composition of the metallic particles consists of a metal selected from the list mentioned above or consists of a metal Alloy comprising one of the metals selected from the list mentioned above.

Furthermore, it is clear to the person skilled in the art that the metal particles, in the case of induction heating, can continue to have a positive effect on the curing behavior due to electrical or induction-related effects.

The metallic particles can be designed differently. The metallic particles may, for example, be platy, ribbon-like,

be rod-shaped, cuboidal, cube-shaped, conical, frustoconical, pyramidal, truncated pyramidal, spherical, ellipsoidal or spherical. Particularly preferred are such metallic particles which have the most uniform expansion thicknesses possible. The proportion by weight of metallic particles is preferably selected such that the proportion by weight of metallic particles is 1-50% by weight, in particular 2-30% by weight, preferably 2-20% by weight, based on the weight of the thermosetting epoxy composition, is. The thermosetting epoxy composition has spacers in a particularly preferred embodiment. As a spacer, in the present document a body is understood which holds two bodies at a distance from each other when the spacer is located between these two bodies.

The spacer can be designed differently. Very different materials and shapes of spacers can be used. Particularly preferred are such spacers which have the most uniform expansion thicknesses possible. Furthermore, preference is given to spacers of this type which have no tips which are perpendicular to the inner panel and / or outer panel, because the sheet could deform due to the small contact surface of the outer panel and / or the inner panel at the high compression pressure, so that the position the spacer on can sign off the outer panel, which is optically often unacceptable. Particularly preferred are balls and cubes as spacers.

The spacers have in particular a spherical shape, preferably a spherical shape. Most preferred are spherical spacers.

The spacers can be hollow or filled. Hollow spacers are often preferred for weight reasons. The wall thickness of such hollow spacers depends on the mechanical properties of the wall material, in particular its compressive strength. Examples of such hollow spacers are hollow glass spheres and ceramic hollow spheres.

The spacers can be made of different materials. In particular, it is of great advantage for the present method if the spacer is pressure-stable and as hard as possible.

Thus, the composition of the spacer advantageously has a hardness measured by hardness test method Vickers DIN ISO 6507: 2005 of greater than 200 HV 1, preferably greater than 400 HV 1, in particular greater than 600 HV 1 on.

Namely, it is advantageous if the spacer resists the pressure during the pressing. The spacer is therefore in particular made of glass, ceramic, aluminum oxide, silicon dioxide, zirconium oxide, nitride, in particular boron nitride, or carbide, in particular silicon carbide.

The spacer advantageously has as close as possible

Size distribution, in particular via a monomodal size distribution, i. that all spacers are approximately the same size.

Most preferably, the spacer is made of glass or ceramic.

The proportion of the spacer is preferably selected such that the volume fraction of the spacer is not more than 10% by volume, in particular between 0.1 and 4% by volume, preferably between 0.5 and 3% by volume, based on the total volume of the thermosetting epoxy composition.

The spacers advantageously have a particle size of less than 1 mm. It is particularly advantageous if the metallic particles have an average particle size which is 10 -500%, preferably 150-400%, of the average particle size of the spacers. Preferably, the thermosetting epoxy resin composition further contains at least one toughener D.

By a "toughener" is meant in this document an addition to an epoxy resin matrix, which is already at low

Supplements of 0.1-50 wt .-%, in particular from 0.5 to 40 wt .-%, causes a significant increase in toughness and thus is able to absorb higher bending, tensile, impact or impact stress before the matrix enters or breaks.

The toughener D can be a solid or a liquid

Toughener, especially a liquid toughener.

In a first embodiment, the toughener D is a

Acrylonitile / butadiene copolymer, which with carboxyl groups or

(Meth) acrylate groups or epoxide groups terminated, or is a derivative thereof.

Such liquid rubbers are, for example, under the name Hypro®, formerly Hycar®, CTBN and CTBNX and ETBN of

Nanoresins AG, Germany commercially available. As derivatives in particular epoxy-containing elastomer-modified polymers, such as those under the product line Polydis®, preferably from the product line Polydis® 36, the company Struktol® (Schill + Seilacher Group, Germany) or under the product line Albipox (Nanoresins, Germany) are commercially available, suitable.

In a second embodiment, this toughener D is a polyacrylate liquid rubber which is completely miscible with liquid epoxy resins and does not adhere until the epoxy resin matrix cures

Microdroplets segregated. Such polyacrylate liquid rubbers are available, for example, under the designation 20208-XPA from Rohm and Haas. In a third embodiment, this toughener D is a polyether amide terminated with carboxyl groups or epoxide groups. Such polyamides are in particular produced from the reaction of amino-terminated polyethylene ethers or polypropylene ethers, as described in US Pat

Example, be marketed under the name Jeffamine® by Huntsman, with dicarboxylic anhydride subsequent reaction with epoxy resins, as described in Example 15 in conjunction with Example 13 of DE 2123033. Hydroxybenzoic acid or hydroxybenzoates may be used instead of dicarboxylic acid anhydride.

In a fourth, most preferred embodiment, the

Toughener D is a terminally blocked polyurethane prepolymer of formula (I).

Here, R ^{1 is} a p-valent radical of an isocyanate-terminated linear or branched polyurethane prepolymer PU1 after removal of the terminal isocyanate groups and p is from 2 to 8.

Furthermore, R ^{2 is} independently a substituent which is selected from the group consisting of

Here, R ⁵ , R ⁶ , R ⁷ and R ^{8 are} each independently an alkyl or cycloalkyl or aralkyl or arylalkyl group, or R ⁵ forms together with R ⁶ , or R ⁷ together with R ⁸ , a part of a 4- to 7-membered ring, which is possibly substituted.

Furthermore, R ⁹ and R ^{10 are} each independently an alkyl or aralkyl or arylalkyl group or an alkyloxy or aryloxy or aralkyloxy group and R ^{11 is} an alkyl group.

R ¹² , R ¹³ and R ¹⁴ each independently represent a

Alkylene group having 2 to 5 carbon atoms, which optionally has double bonds or is substituted, or for a phenylene group or for a hydrogenated phenylene group.

R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently H or an alkyl group, or an aryl group or an aralkyl group, and R ¹⁸ is an aralkyl group or a mono- or polynuclear substituted or unsubstituted aromatic group which optionally has aromatic hydroxyl groups having.

Finally, R ^{4 is} a radical of a primary or secondary hydroxyl-containing aliphatic, cycloaliphatic, aromatic or araliphatic epoxide after removal of the hydroxide and

Epoxide groups and m for a value of 1, 2 or 3.

The term "independently of one another" is to be interpreted in this document as meaning that the identically named substituents, radicals or groups can occur simultaneously with different meanings in the same molecule, resulting, for example, in the formula (I) of the p radicals R ² not all have to represent the same rest, but they can, within the definition of R ² possible, be different

Have meanings. Thus, in extreme cases, it is possible for the terminally blocked polyurethane prepolymer of the formula (I) to have 8 radicals R ^{2 which} are different from one another.

The dashed lines in the formulas of this document each represent the bond between the respective substituent and the

As R ¹⁸ are in particular on the one hand phenols or polyphenols, especially bisphenols, to consider after removal of a hydroxyl group. Preferred examples of such phenols and bisphenols are, in particular, phenol, cresol, resorcinol, pyrocatechol, cardanol (3-penta-decenylphenol (from cashew nut shell oil)), nonylphenol, phenols reacted with styrene or dicyclopentadiene, bisphenol A, bis Phenol-F and 2,2'-diallyl-bisphenol-A.

On the other hand, as R ¹⁸ , in particular, hydroxybenzyl alcohol and benzyl alcohol are considered after removal of a hydroxyl group.

If R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ^{9 '} , R ¹⁰ , R ¹¹ , R ¹⁵ , R ¹⁶ or R ^{17 is} an alkyl group, this is in particular a linear or branched d- C2o-alkyl group.

If R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ^{9 '} , R ¹⁰ , R ¹⁵ , R ¹⁶ , R ¹⁷ or R ¹⁸ for a

Aralkyl group, this group is in particular an aromatic group bound via methylene, in particular a benzyl group.

If R ^5, R ^6, R ^7, R ^8, R ^9, R ^{9 'or} R ¹⁰ is an alkylaryl group, this is particularly a group bonded through phenylene d- to C2o-alkyl group, such as a tolyl or xylyl group ,

The radicals R ² are preferably the substituents of the formulas

O

12

NO

As a substituent of the formula ε-caprolactam is preferred after removal of the NH proton.

- - -No

Preferred substituents of the formula are monophenols or polyphenols, in particular bisphenols, after removal of a phenolic hydrogen atom. Particularly preferred examples of such radicals R ² are radicals which are selected from the group consisting of

The radical Y in this case represents a saturated or olefinically unsaturated hydrocarbon radical having 1 to 20 C atoms, in particular having 1 to 15 C atoms. As Y, in particular allyl, methyl, nonyl, dodecyl or an unsaturated Ci ₅ alkyl radical having 1 to 3 double bonds are preferred.

The preparation of a terminally blocked polyurethane prepolymer of the formula (I) is disclosed, for example, in the patent EP 1935955 A1 in the sections [0040] to [0077], the content of which is hereby incorporated by reference in particular. For the preparation of a terminally blocked polyurethane prepolymer of the formula (I), therefore, an isocyanate-terminated linear or branched polyurethane prepolymer PU1 reacts with an isocyanate-reactive one

Compounds R ² H.

Most preferably R ^{2 is} , which is from the

Isocyanate-reactive compounds R ² H of the formula (V) gives.

If several such monohydroxyl-epoxy compounds are used, the reaction can be carried out sequentially or with a mixture of these compounds.

The monohydroxyl epoxy compound of the formula (V) has 1, 2 or 3

Epoxide groups on. The hydroxyl group of this monohydroxyl epoxy compound (V) may be a primary or a secondary hydroxyl group.

Such monohydroxyl epoxy compounds can be produced, for example, by reacting polyols with epichlorohydrin. Depending on

In the reaction of polyfunctional alcohols with epichlorohydrin as by-products, the reaction also results in the corresponding monohydroxy-epoxy compounds in different concentrations. These can be isolated by conventional separation operations. In general, however, it is sufficient to use the product mixture obtained in the glycidylation reaction of polyols from polyol reacted completely and partially to the glycidyl ether. Examples of such hydroxyl-containing epoxides are butanediol monoglycidyl ethers (contained in butanediol diglycidyl ether), hexanediol monoglycidyl ether (contained in hexanediol diglycidyl ether), cyclohexanedimethanol glycidyl ether, trimethylolpropane diglycidyl ether (contained in trimethylolpropane triglycidyl ether mixture), glycerol diglycidyl ether (contained as a mixture in US Pat

Glycerol triglycidyl ether), pentaerythritol triglycidyl ether (as a mixture contained in pentaerythritol tetraglycidyl ether). Preferably, trimethylolpropane diglycidyl ether, which occurs in a relatively high proportion in commonly prepared Trimethylolpropantriglycidylether used.

However, it is also possible to use other similar hydroxyl-containing epoxides, in particular glycidol, 3-glycidyloxybenzyl alcohol or hydroxymethylcyclohexene oxide. Preference is furthermore given to the β-hydroxy ether of the formula (IX) which is present in commercially available liquid epoxy resins prepared from bisphenol A (R =CH ₃ ) and epichlorohydrin and contains about 15%, and the corresponding β-hydroxy ethers of the formula (IX ) formed in the reaction of bisphenol-F (R = H) or the mixture of bisphenol-A and bisphenol-F with E-chlorohydrin.

Also preferred are distillation residues, which are obtained in the production of high purity, distilled epoxy liquid resins. Such distillation residues have an up to three times higher concentration of hydroxyl-containing epoxides than commercially available undistilled epoxide

Liquid resins. In addition, a wide variety of epoxides with a ß-hydroxy ether group, prepared by the reaction of (poly) epoxides with a deficit of monovalent nucleophiles such as carboxylic acids, phenols, thiols or sec-amines, can be used.

The radical R ⁴ is in particular vorzu t a trivalent radical of the formula

where R is methyl or H.

The free primary or secondary OH functionality of the monohydroxyl epoxy compound of the formula (V) permits efficient reaction terminal isocyanate groups of prepolymers, without having to use disproportionate excesses of the epoxy component.

It is clear to the person skilled in the art that, of course, mixtures of tougheners D can also be used.

The amount of toughener D, in particular of the

terminally blocked polyurethane prepolymer of the formula (I), is advantageously between 1 and 50% by weight, in particular between 3 and 40% by weight, based on the total weight of the thermosetting

Epoxy.

The thermosetting epoxy composition is preferably highly viscous, that is, it has a viscosity of more than 900 Pas, in particular more than 1000 Pas, at 25 ° C. Preferably, the viscosity at 25 ° C has a value between 1000 Pas and 4000 Pas. The viscosity is measured by oscillography using a rheometer with heatable plate (MCR 201, Anton Paar company) (gap 1000 μιτι, measuring plate diameter: 25 mm (plate / plate), deformation 0.01 at 5 Hz, temperature: 25 ° C), certainly.

Preferably, in the thermosetting epoxy composition, thermosetting one-part epoxy resin adhesives as described in U.S. Pat

SikaPower® product line are commercially available from Sika Automotive GmbH.

Another aspect of the invention relates to a method for producing a Bördelfalzverklebung. This includes at least the steps

a) application of a thermosetting epoxy composition, as mentioned above, on an inner panel or on a

Outer panel;

b) contacting the thermosetting epoxy composition with the outer panel or the inner panel; c) flanging the outer sheet around the inner sheet, so that in the interior of the crimp fold heat-curing epoxy composition is present;

d) pressing the edging fold;

e) introducing thermal energy into the thermosetting epoxy composition.

The thermosetting epoxy composition is applied in a first step (a) of the inventive method to an inner panel or an outer panel. This is done advantageously at a

Application temperature of the thermosetting epoxy composition of 23 ° C to 80 ° C, in particular from 23 ° C and 60 ° C, preferably from 50 to 60 ° C.

The order of the thermosetting epoxy composition, im

Also called adhesive below, typically takes place in the edge area of the outer panel. The amount and exact application point of the adhesive is such that after the compression of the crimp fold described below, it is filled as completely as possible with adhesive. The order is preferably carried out automatically and preferably in the form of an adhesive caterpillar. In a second step (b) of the method according to the invention, the adhesive is then contacted with the outer panel or the inner panel. Thus, the inner plate and the outer plate are in contact with the adhesive.

Of course, it is also possible that a plurality of inner sheets, which are glued together with repetition of steps a) and b) can be used for the production of a Bördelfalzes.

In a third step (c) of the method according to the invention, the outer panel is crimped around the inner panel, so that adhesive is present in the interior of the fold thus formed.

In a fourth step (d) of the method according to the invention, the crimp fold is then pressed. Preferably, the pressing of the

Bördelfalzes on an adhesive layer thickness (d _x ), which corresponds to the thickness (d _y ) of the optionally present spacer. As the thickness of the spacer, also referred to as "d _y ", in this document, the thickness of the spacer perpendicular to

Outer panel surface. Geometrically even more accurate is the thickness of the

Spacer as a spatial extension of the spacer in the

Normal vector of the tangential surface of the inner sheet surface at the

Spacer nearest point defined parallel standing direction.

Compression reduces the thickness of the adhesive layer, which is also referred to as "d _x " in this document, to correspond to the thickness of the spacer, and the term "equivalent" in this context is not "absolutely identical". It also includes small deviations from this value, which typically amount to a maximum of 10% In the case of an absolute identity, there would be no adhesive binder, ie reactive adhesive constituents, between the spacer and the inner sheet or outer sheet but it is advantageous if there is a thin layer of adhesive binder between the spacer and the inner panel and / or outer panel.

The thickness of the spacer is influenced in particular above all by the thickness of the flanging fold to be achieved, and thus in particular by the thickness of the outer panel, also referred to in this document as "d _z ." Preferably, the ratio of the thickness (d _y ) of the spacer to The thickness (d _z ) of the outer sheet has a value of 0.05-0.70 For a typical thickness of an outer sheet for a Bördelfalzverklebung of 0.5 to 1 .5 mm therefore spacers of the thickness of in particular 0.08 to 0.4 mm are used 0.2 mm and outer plates of thickness 0.5 to 1.2 mm The thickness of the inner plates is preferably selected in the same thickness range as the outer plate.

As the inner plate and outer plate, in principle, all the plates known by the expert are suitable. In particular, these are those sheet materials which are already used for edge banding in transport construction or in the production of white goods.

Preferred sheets are steel, in particular electrolytically galvanized, hot-dip galvanized, oiled steel, Bonazink-coated steel, and subsequently phosphated steel, as well as aluminum in particular in the variants typically occurring in the car industry.

The crimping and pressing takes place with tools known to the person skilled in the art.

In a further step (e) of the process according to the invention, thermal energy is introduced into the adhesive. The feeding of the thermal energy causes the crosslinking of the adhesive in thermosetting adhesives, or accelerates the crosslinking of the adhesive, so that a sufficiently high strength of Bördelfalzverklebung is achieved as quickly as possible.

Thus, preferably following step e), a step f) of crosslinking of the adhesive follows. The thermal energy is in particular about heating in one

Furnace, via infrared radiation or induction heating, preferably via induction heating, introduced into the adhesive.

It is advantageous if, by introducing thermal energy, the adhesive is heated to a temperature of 100-220 ° C., preferably 120-200 ° C.

The final cross-linking can also take place in the cathodic rotary kiln.

Another aspect of the invention relates to a Bördelfalzverklebung, which is prepared by the method described above.

Furthermore, the invention relates to the use of the method described above for the production of Bordelfalzverklebungen in the production of means of transport, especially of automobiles, buses, trucks, rail vehicles, ships or aircraft, or white goods, especially washing machines, tumblers or dishwashers.

Finally, in a further aspect of the invention, an article which has a described Bördelfalzverklebung claimed

Such articles or hem flange adhesive-bonded bodies are in particular means of transport, in particular an automobile, bus, truck, rail vehicle. vehicle, a ship or an aircraft, or a white goods, in particular a washing machine, tumbler or dishwasher.

Short description of the drawing

In the following selected embodiments of the invention will be explained in more detail with reference to the drawings. The same elements are provided in the various figures with the same reference numerals. The direction of forces or movements is indicated by arrows.

Show it:

Fig. 1 a-e is a schematic cross-sectional view of the production of a

Crimp seam bonding of the prior art comprising different stages

Fig. 1 a application of an adhesive on the outer panel

Fig. 1 b application of an adhesive with spacers on the

outer panel

Fig. 1 c contacting the adhesive with spacers with the

inner panel

Fig. 1 e Beading of the outer panel and pressing the Bördelfalzes Fig. 1 e introducing thermal energy and crosslinking of the adhesive Fig. 2a cross-section through an inventive adhesive

Fig. 2b introducing thermal energy and crosslinking of a

adhesive according to the invention

Fig. 2c introducing thermal energy and crosslinking of a

adhesive according to the invention

Fig. 3a cross-section through an inventive adhesive

Fig. 3b inventive adhesive before pressing

Fig. 3c introducing thermal energy and crosslinking of a

adhesive according to the invention

FIGS. 1 a to 1 e show diagrammatically different intermediate stages in a possible method for producing a

Bördelfalzverklebung. The non-inventive adhesive 4 '(without metallic particles) can be used without spacers 6, as shown in FIG. 1 a, or with spacers, as shown in FIGS. 1 b to 1 e. The order of the non-inventive adhesive 4 'takes place in this representation in the form of a round bead in the region of the edge region of the outer panel 2, where the contact with the inner panel 3 is to take place. The outer panel 2 already has a deformation of the in this illustration

Border area on. Such reshaping may already exist prior to the application of the adhesive or may take place as part of the crimping. The spacers 5 are in the figures 1 b to 1 e balls.

Figure 1 c shows schematically how the non-inventive adhesive 4 'is contacted with the inner panel 3. In this presentation, the

Inner sheet 3 from above on the non-inventive adhesive 4 'occupied outer sheet 2 moves out and it is under slight pressure contact between inner sheet 3 and non-inventive adhesive 4'.

FIG. 1d shows the result of crimping the outer sheet 2 about the inner sheet 3 with subsequent pressing of the crimp fold 1 to an adhesive layer thickness d _x , which corresponds to the thickness d _{y of} the spacer 6. FIG. 1d shows the intermediate stage after these two process steps.

Figure 1 e shows the step of introducing thermal energy (Δ) in the non-inventive adhesive 4 '. This is done by

Crosslinking of the adhesive. The thermal energy can be done for example by an IR emitter, oven or Heißluftföhn. The heated

Outer sheet 2 transfers the heat to the non-inventive adhesive 4 ', which then crosslinked under heat. Optimally, an all-round effect of heat around the hem flange to achieve a rapid uniform hardening of the adhesive 4 'would be achieved.

FIG. 2a shows a cross-section through an adhesive 4 according to the invention, which is a thermosetting epoxy composition as described in the section "Methods of Carrying Out the Invention". described is. The term "adhesive according to the invention" is therefore to be understood as meaning a use according to the invention. <br/> [0026] FIG. 2b shows the introduction of thermal energy and crosslinking of an adhesive according to the invention, wherein FIG

Magnification of the dashed area in Figure 2b, which specifically shows the heat input into the adhesive 4.

In Figure 2c it can be seen that the heat input over the

Outer sheet 2, respectively the inner sheet 3, when using a

adhesive according to the invention not only on the basis of the heat output 7 of the outer panel 2, respectively the heat output 8 of the inner panel 3, takes place, but in addition on the heat output 9 of the metallic particles. 5

Since the adhesive layer thickness d _{x is} less than the diameter of the metallic particles 5 prior to compression, the compression process leads to a contact on both sides of the metallic particles with the outer panel, respectively the inner panel, with deformation of the metallic particle 5. Due to the higher thermal conductivity of the metallic particles the corresponding adhesive without metallic particles is a faster heat input compared to a non-inventive adhesive that has no metallic particles or only metallic particles whose diameter is smaller than the adhesive layer thickness d _x .

Figures 3a, 3b and 3c show the same facts as Figures 2a to 2c, wherein the adhesive composition additionally

Spacer having the thickness d _y . This is advantageous in that thereby the adhesive layer thickness d _x can be adjusted over the thickness of the spacer 6 d _y , whereby the additional heat input of the metallic particles can be controlled better over a controlled adhesive layer thickness d _x .

LIST OF REFERENCE NUMBERS

1 edging fold 7 heat dissipation outer sheet 2

V Bördelfalz-Klebverbundkörper 8 Heat output inner panel 3

2 outer panel 9 heat dissipation metallic

Particles 5 3 inner panel adhesive layer thickness

4 Inventive adhesive Thickness of the spacer 5

4 'Non-inventive thickness of the outer panel 2

adhesive

5 Metallic particles Thermal energy

6 spacers

Examples

SikaPower®-492 is a thermosetting epoxy resin adhesive commercially available from Sika Automotive GmbH containing one

Toughening agent of the formula (I). This has at 25 ° C a viscosity of about 2700 Pas and at 50 ° C of about 1000 Pas. Glass beads (Sigmund Lindner GmbH, Germany) of diameter 0.1-0.11 mm, 0.25-0.3 mm, or 1 .2 mm were also added to the adhesive with stirring. The added amount of glass beads was 2% by volume based on the

Final composition. This comparative adhesive was designated VK1.

An adhesive K1 according to the invention was also prepared by adding to SikaPower®-492 aluminum particles (Ecka Aluminum AS 91) with a diameter smaller than 0.315 mm and glass beads (Sigmund Lindner GmbH, Germany) of diameter 0.1-0.1 1 mm, 0.25-0.3 mm , or 1 .2 mm was added with stirring. The amount added

Glass beads was 2% by volume, the added amount of aluminum particles was 9% by weight based on the final composition.

The substrate used on the one hand was electrolytically galvanized sheet steel (DC-04) with a thickness of 0.8 mm (also referred to below as sheet for short), which was previously cleaned using heptane.

As a substrate, on the other hand, a plastic test piece (Rocholl GmbH, Germany) made of glass fiber reinforced plastic having a thickness of 2.4 mm (hereinafter also referred to simply as GFR) was used, which was used without prior purification. The respective adhesive was at 50 ° C on an adhesive surface of 25 x 10 mm on an electrolytically galvanized steel sheet, respectively. one

Glass fiber reinforced plastic test specimen applied and another sheet (thickness 0.8 mm), resp. GRP (thickness 2.4 mm) placed and pressed.

These samples were then subjected to induction hardening at 17.5 kHz, heating within 30 seconds to a temperature of 170 ° C and then the temperature for a further 30

Seconds was kept constant.

The tensile shear strength (ZSF) of the specimens was according to DIN EN

1465 determined. The pulling speed was 10 mm / min.

Table 1 . Test results of the compositions. n.m. = not measurable because not thickened.

The adhesive K1 according to the invention contains, in the composition with glass spheres of 0.1 mm diameter, metallic particles which have a larger particle diameter, in this case up to 300% larger particle diameter, than the glass spheres used as spacers. The metallic aluminum particles are therefore due to the pressing on both sides with a significant proportion of the surface in contact with the sheet and thereby lead to an additional

Heat input into the adhesive.

From the results of Table 1 it can be seen that the

Inventive adhesive K1, in the case of glass beads with 0.1 mm

Diameter, compared to the comparative adhesive VK1 a significantly higher Has tensile shear strength. The higher tensile shear strength compared to the comparative adhesive VK1 is due to the better curing of the

Adhesive due to the additional heat input through the standing on both sides in contact with the metal sheet metal particles.

Due to the fact that fiberglass is not chosen by the

Induction parameters, a tensile shear strength measurement could not be determined due to the lack of cure of the adhesives.

Claims

claims

1 . Use of a thermosetting epoxy composition comprising - at least one epoxy resin A having an average of more than one

Epoxide group per molecule;

- At least one hardener B for epoxy resins, which increased by

Temperature is activated; such as

Metallic particles with an average particle size of 50

- 3000 in

as an adhesive in edging seams.

Use according to claim 1, characterized in that the thermosetting epoxy composition additionally comprises at least one toughener D, in particular a terminally blocked polyurethane prepolymer of the formula (I);

wherein R is a p-valent radical of an isocyanate-terminated linear or branched polyurethane prepolymer PU1 after removal of the terminal isocyanate groups;

p is a value from 2 to 8; and

R ^{2 is} independently a substituent selected from the group consisting of

in which

R ⁵ , R ⁶ , R ⁷ and R ^{8 are} each independently an alkyl or

Cycloalkyl or aralkyl or arylalkyl group

or R ⁵ together with R ⁶ , or R ⁷ together with R ⁸ , a part of a

Form 4- to 7-membered rings, which is at most substituted;

R ⁹ , R ⁹ and R ¹⁰ each independently represent an alkyl or aralkyl or arylalkyl group or an alkyloxy or aryloxy or

Aralkyloxy group;

R ^{11 is} an alkyl group,

R ¹² , R ¹³ and R ¹⁴ each independently represent an alkylene group having 2 to 5 C atoms, which optionally has double bonds or is substituted, or stand for a phenylene group or for a hydrogenated phenylene group;

R ¹⁵ , R ¹⁶ and R ¹⁷ each independently represent H or an alkyl group, or an aryl group or an aralkyl group; and R ^{18 is} an aralkyl group or a mononuclear or polynuclear one

substituted or unsubstituted aromatic group which optionally has aromatic hydroxyl groups;

R ^{4 is} a radical of a primary or secondary hydroxyl-containing aliphatic, cycloaliphatic, aromatic or araliphatic epoxide after removal of the hydroxide and

Epoxy groups;

and m for a value of 1,

2 or 3 stands.

3. Use according to one of the preceding claims, characterized in that the metallic particles have an average Particle size of 100 to 1000 μητι, preferably from 200 to 400 μητι have.

4. Use according to one of the preceding claims, character- ized in that the composition of the metallic particles a

Hardness measured according to hardness test method Vickers DIN ISO 6507: 2005 of less than 120 HV 1, preferably less than 50 HV 1, particularly preferably less than 30 HV 1.

5. Use according to one of the preceding claims, characterized in that the composition of the metallic particles has a thermal conductivity of greater than 10 W / (mK), preferably greater than 50 W / (mK), particularly preferably greater than 100 W / (mK) having.

6. Use according to one of the preceding claims, characterized in that the composition of the metallic particles contains a metal which is selected from the list consisting of aluminum, copper, tin, zinc, chromium, iron, nickel and lead.

7. Use according to one of the preceding claims, characterized in that the proportion by weight of metallic particles 1 - 50 wt .-%, in particular 2 - 30 wt .-%, preferably 2 - 20 wt .-%, based on the weight of the thermosetting Epoxy composition is.

8. Use according to one of the preceding claims, characterized in that the thermosetting epoxy composition further comprises spacers.

9. Use according to claim 8, characterized in that the composition of the spacers measured according to a hardness

Hardness test method Vickers DIN ISO 6507: 2005 of greater than 200 HV 1.

10. Use according to claim 8 or 9, characterized in that the metallic particles have an average particle size

which is 10 -500%, preferably 150-400%, of the average particle size of the spacers.

1 1. A method for producing a Bördelfalzverklebung comprising

at least the steps

a) application of a thermosetting epoxy composition, as described in any one of claims 1 to 10, on an inner panel (3) or on an outer panel (2);

b) contacting the thermosetting epoxy composition (4) with the outer panel (2) or the inner panel (3);

c) flanging the outer plate (2) to the inner plate (3), so that in the interior (1 1) of the edging fold (1) thermosetting

Epoxy composition (4) is present;

d) pressing the edging fold (1);

e) introducing thermal energy into the thermosetting

Epoxy composition (4).

12. The method according to claim 1 1, characterized in that the

Introducing thermal energy into the thermosetting

Epoxy composition (10) is carried out by induction heating.

13 Bördelfalzverklebung prepared by a method according to claim 1 1 or 12th

14. Use of a method for producing Bördelfalzverklebungen according to one of claims 1 1 or 12 in the production of means of transport, in particular of automobiles, buses, trucks, rail vehicles, ships or aircraft, or white goods, especially washing machines, tumblers or dishwashers.