DE102006038624A1 - Method for fixing a component on a joining partner to be painted - Google Patents

Abstract

Method for fixing a component on a joining partner to be painted, wherein the component is fixed with a portion of a not fully crosslinked heat-activated adhesive film on the joining partner, the joining partner is painted together with the component fixed thereto, the painted joining partner together with the component fixed thereto in a thermal Drying is dried, wherein the thermal energy leads to a complete crosslinking of the heat-activated adhesive film, so that the component is permanently fixed on the joining partner.

Description

The The invention relates to a method for fixing a component a joining partner to be painted.

At Automobile bodies are now undergoing many parts firmly adhered a permanently adhesive. This applies to bolts or similar Parts that serve themselves again, that later in them further components, especially plastic parts, can be attached.

It is particularly known, for example, such bolts by means of a two-component liquid adhesive to stick (structural bonding). This makes a complex mix and dosage of liquid systems while of cultivation necessary. The complicated processing (such as Mix, stick to pot life, frequent Pollution) is disadvantageous to these systems, even if for lack of alternatives, for example in Scheibenverklebung have enforced. The final layer thickness is beyond that difficult to set exactly. Bolt or nut constructions with plate-shaped Walk to Magnification of the adhesive surface are also known.

From the FR 2 542 829 A An adhesive bond is known in which this is achieved by a double-sided effective pressure-sensitive adhesive tape whose outwardly facing adhesive surface is first covered by a thin film and is effective only after removal of the film. Apart from the fact that the previous removal of the protective film is perceived as cumbersome, the adhesive connection experience does not reach the required holding force for a permanent connection between the protective strip and the body surface. There is also a risk that the protective film will be damaged during transport and then stick the parts together. This type of adhesive attachment has apparently not proven in the automotive industry and is therefore hardly used. Similar adhesive-coated fasteners are made DE 87 12 151 U1 known.

From the US 4,250,596 A a glued fastener is known in which the adhesive surface is equipped with a curable hot melt adhesive, which can be reactivated by means of heat to produce a permanent adhesive bond. The known thermosetting adhesive has the property of softening at the temperature at which the final coating of the paint applied to the body is cured, and it solidifies when the applied paint coat cools. However, this means that the fasteners must be kept as long on the body panel during the adhesive until the cooled adhesive has entered a strong adhesive bond. Since the curing of the adhesive usually takes about 30 minutes at a baking temperature of 180 ° C, the holding means must remain in use during this time.

Furthermore, are known from the EP 0 741 842 B1 Fasteners, which are equipped by means of injection molding with a layer of a hardenable reactive hot melt adhesive. Similar fasteners having a component-sintered reactive polyurethane adhesive layer are sold under the Techbond brand by Raybond (Saint-Louis, France). The adhesive application is very high here with about 900 microns thick, resulting in the squeezing of the adhesive from the adhesive joint under the pressure of the binding process. Moreover, disadvantageous in both of the aforementioned fasteners of the great effort for injection molding or sintering (in particular the equipment and tool costs), which must be driven to produce the adhesive layers. That in the EP 0 741 842 B1 alternatively proposed immersion of the fasteners to be coated in a bath of molten adhesive leads to less accurate application rates and uneven adhesive surfaces due to the adhesive flow.

Problematic for one Fixing with an adhesive is that painted the bodies become. The bolts, for example, can after the painting process no longer be glued on the paint, because this is not a good Haftgrund offers. On the other hand would be an appropriate treatment the body after painting, for example, a partial Removal of the paint, far too expensive.

Of the Bonding process must therefore be done before the painting process. there the problem arises that the adhesive used on the one hand the while survives the painting processes and on the other hand against the during the Painting used media, for example the solvents, insensitive. In particular, the adhesive must not contain any components in the respective baths because this causes contamination of the paint baths, which in turn for obvious reasons very unwanted premature replacement of the same led.

Of Furthermore, it is necessary that the adhesive sufficient Having initial tack, so that the desired component immediately on the ground at least fixed so far that the bonding is a mechanical Withstand stress, until optionally the adhesive has its final bond strength in subsequent process steps reached.

adversely to the aforementioned solutions of The prior art is that the adhesive initially largely its final bond strength must have reached to withstand the painting process. At networking This means waiting for longer curing times before painting can be started.

The sequence of an industrial series painting of automobile bodies is as follows. A visual overview gives the 1 ,

To The assembly becomes the body of adhering contaminants like fats, oils and dirt particles cleaned in a multi-stage degreasing and rinsing zone. at The degreasing will usually be alkaline cleaners and possibly additional Surfactants used. The subsequent rinsing takes place with water.

in the Following the cleaning process, the phosphating, nowadays usually a zinc phosphating.

Under Phosphating is the preparation of a sparingly soluble Metal phosphate layer on the metallic body, the Substrate. This process is anti-corrosion though the result represents, always associated with corrosion. By chemical operations becomes a necessary pickling reaction due to the acid phosphating solution fires which not only the top (almost not measurably small) metal layers dissolves, but also at the same time the last impurities are blasted off. When phosphating the steel component is either immersed in a metal phosphate bath or in a chamber sprayed with metal phosphate solution. It forms on the surface an approx. 1 to 30 μm thin, metal phosphate layer firmly bonded to the base material. It These may be iron, manganese or zinc phosphate layers. The Metal phosphate layer serves as a primer for a paint coating and prevents sub-rusting of the paint layer. Further fields of application are the phosphating for Cold forming of steel in combination with lubricants, corrosion protection in conjunction with corrosion inhibitors such as oils and the reduction of wear in manganese phosphating.

Around in the course training as possible To produce many small crystals, the body is in one activating solution pre-rinsed. The polymeric titanium phosphates contained therein act as crystallization nuclei for the subsequent Zinc phosphate. Since the highest demands are placed on corrosion resistance, the Zinc phosphating of iron phosphating preferred. The zinc phosphating baths are acidified (pH 3) and usually contain as a layer-forming Substances Manganese, nickel and zinc phosphates as well as various additives for better process management and for suppression the gas bubble formation in the irritant reaction. In zinc phosphating is formed by the reaction of the phosphating solution with the base material a firmly adherent fine crystalline zinc phosphate layer. The accruing Sludge from reaction products must be removed from the process. After phosphating, a multiple rinse with demineralized water and a Nachpassivierung, in which the spaces within the phosphate layer are closed. Here are Nachpassivierungsbäder, on Base of organic polymers or zirconium salts available. The Only a few thousandths of a millimeter thick phosphate layer forms a ideal primer for the paint.

Then done the electrocoating.

The Electrophoretic painting (electrocoating) stops Dipping process in which the coating by the action of a electric field (50 to 400 V) takes place. The paint to be painted, The electric current conducting body is called the anode or cathode introduced into the dye bath, in practice, the pelvic wall acts as a second electrode. The deposited amount of paint is the amount of electricity supplied directly proportional. Electrophoretic painting becomes special used for primer. There are no splash losses, and the resulting coatings are also difficult to access Make it very even. For non-conductive Documents, for example, plastics, glass, ceramics, etc. operated to coat the electrostatic charge of the paint particles (so-called electrostatic painting). All electrocoating paints are water-soluble (Suspensions of binders and pigments in demineralized water) with only low concentrations of organic solvents (about 3%). Thus, neither fire protection nor special occupational safety measures necessary when operating KTL systems

As already mentioned, cathodic dip painting is used in the automotive industry. prefers. The KTL bath consists of about 80% water, 19% are binders and pigments, only about 1 to 2% are organic solvents. The pH is slightly acidic and is about 6 to 6.5. The deposition mechanism is divided into several stages: The water-insoluble synthetic resin becomes dispersible in water only in combination with an organic acid. In the area of the negatively charged workpiece (cathode), an alkaline boundary layer formation (pH 11 to 13) occurs due to the evolution of hydrogen. Due to the increased OH concentration on the workpiece surface, the paint dissolved in the water coagulates and separates in the form of a fine paint layer on the component. In order to prevent sedimentation and to exclude the formation of dead spaces, the bath in the tank at an average flow rate of about 0.2 m / s is moved, based on the tank contents, the bath is circulated 4 to 6 times per hour. With a paint consumption of 2 to 3 kg / body and a non-negligible water evaporation at bath temperatures around 30 ° C, a constant control of the bath composition is required. The organic acids released at the anode are separated by a dialysis system and thus the pH of the bath is kept stable.

Then follows a multi-stage rinsing zone with ultrafiltrate from the paint recovery or demineralized water.

Of the Paint is at about 180 ° C baked, the layer thickness is 20 to 30 microns. Depending on Process variant is still an additional second coat of paint as filling layer applied. Only now does the actual painting with the coloring topcoat, as well as the clearcoat.

If in the following, the solvent-free paint the speech is watery Paints, powder coatings or powder slurries meant.

At the Powder coating is a coating process, in which a usually electrically conductive material with powder coatings is coated. The powder becomes electrostatic or tribostatic sprayed onto the substrate to be coated and then baked. In advance is the workpiece to degrease well and if necessary to treat with corrosion protection. These days you can the baking temperatures, depending on the application, vary greatly. Typical stoving conditions are between 140 and 200 ° C. It will Various binders are used today, but are typical Powder coatings based on, for example, polyurethane, epoxy or Polyester resins. Alternatively, the powder may also be by vortex sintering be applied. In this case, a heated workpiece is short in a fluidized by means of compressed air powder made of plastic dipped. The on the surface adhered powder melts through the heat of the workpiece and covers the surface with a continuous plastic layer.

Powder clearcoats are for example from the DE 42 22 194 A known.

Powder slurry coatings are powder coatings in the form of aqueous dispersions. Such slurries are for example in the US 4,268,542 A , of the DE 195 18 392 A , of the DE 196 13 547 A and the DE 198 14 471 A described.

task The invention is therefore a method characterized by short joining times for fixing a component on a joint partner to be painted to disposal to make, on the one hand to avoid that the adhesive used or the adhesive film used by the painting and necessary Pre- and after-treatment processes and media are impaired in their function and second, the adhesive used or the adhesive film used adversely affect the painting process or the thereto affected media.

Is solved this task by a method as laid down in the main claim is. Subject of the dependent claims are advantageous developments of the method according to the invention.

• • das Bauteil mit einem Abschnitt einer nicht vollständig vernetzten hitzeaktivierbaren Klebefolie auf dem Fügepartner fixiert wird,
• • der Fügepartner mitsamt dem darauf fixierten Bauteil lackiert wird,
• • der lackierte Fügepartner mitsamt dem darauf fixierten Bauteil in einer thermischen Trocknung getrocknet wird, wobei die thermische Energie zu einer vollständigen Vernetzung der hitzeaktivierbaren Klebefolie führt, so dass das Bauteil dauerhaft auf dem Fügepartner fixiert ist.

Accordingly, the invention relates to a method for fixing a component on a joining partner to be painted, wherein

• The component is fixed on the joining partner with a section of a not completely crosslinked heat-activatable adhesive film,
• The joining partner is painted together with the component fixed thereon,
• • The painted joining partner is dried together with the component fixed thereto in a thermal drying, wherein the thermal energy leads to a complete crosslinking of the heat-activated adhesive film, so that the component is permanently fixed on the joining partner.

The first fixation of the component with the film section on the joining partner develops at least such a high holding force that the component with its own weight is held in the appropriate position.

These initial, not completely cross-linked adhesive connection holds a painting process, such as a KTL process, stood and impaired not worth mentioning the painting process or the media used therein. In particular, the useful life of a phosphating or KLT bath not significantly reduced.

Of the joining partner exists according to a preferred embodiment made of metal, more preferably it is a body of a vehicle such as watercraft, land vehicles (lorries, Automobiles, etc.), aircraft, spacecraft or combinations hereof, for example amphibious vehicles.

The adhesive film may have a thickness of up to 500 μm. According to an advantageous embodiment of the invention, this is 10 to 250 microns, especially 50 to 200 microns, in the following should be more Re, advantageous embodiments of the adhesive film will be described without wishing to limit the invention.

• i) eines oder mehrere Vinylaromatenblockcopolymere, wobei der Gesamtanteil der Vinylaromatenblockcopolymere an der Klebmasse beträgt 20 Gew.-% bis 75 Gew.-%, bevorzugt 30 Gew.-% bis 70 Gew.-%, besonders bevorzugt 40 Gew.-% bis 60 Gew.-%, und
• ii) eines oder mehrere Klebharze mit einem Erweichungspunkt gemessen nach der Ring- und Kugelmethode (die übliche Standardmethode zur Bestimmung von Erweichungsmethoden (gemäß der Prüfnorm ASTM E 28)) von über 120°C mit einem Anteil von 25 Gew.-% bis 70 Gew.-%.

In an advantageous embodiment, the heat-activatable adhesive film contains at least the following constituents:

• i) one or more vinylaromatic block copolymers, wherein the total proportion of vinylaromatic block copolymers in the adhesive is from 20% by weight to 75% by weight, preferably from 30% by weight to 70% by weight, particularly preferably from 40% by weight to 60 Wt .-%, and
• ii) one or more adhesive resins having a softening point measured by the ring and ball method (the usual standard method for the determination of softening methods (according to the test standard ASTM E 28)) of over 120 ° C in a proportion of 25 wt .-% to 70 wt .-%.

Preferably when the vinylaromatic block copolymers are styrenic block copolymers, in turn, in a particularly advantageous embodiment of Invention styrene-butadiene or styrene-isoprene block copolymers are.

thermoplastic Elastomers, especially those based on block copolymers as elastomeric portion for Adhesives known. Especially in the production of pressure-sensitive adhesives they find use. Vinylaromatic block copolymers, preferably styrenic block copolymers, possess through their block structure and the phase separation implied thereby the soft and hard phases a very high cohesion. Besides they own also a high elasticity, as for the applications in the Moduleverklebung is necessary.

styrene block copolymers alone are not sticky and can also be caused by thermal Activation not be set sticky. A stickiness comes only by the addition of different low molecular weight resins conditions. There is a distinction between two types of resins. First, the mittelblockverträglichen Resins better compatible with the soft block than with the styrene end blocks, and those that are better or only compatible with the endblocks.

The Bonding resistance is enhanced by the use of high melting point Resins with softening points over 120 ° C clearly increased. If only high-melting adhesive resins are used, are the adhesives frequently no longer tacky at room temperature.

The Bonding strengths can by skillful selection of resins those of thermoplastic Reach systems. Beneficial to the simultaneous use of vinyl aromatic block copolymers is the ease of processing both from solution as well as from the melt. By the clever choice of the right one Adhesive resins can the softening point and, consequently, the implantation temperature the adhesives are adjusted very well.

When Adhesives are preferably those based on block copolymers containing polymer blocks formed by vinyl aromatics (A blocks), preferably styrene, and those formed by polymerization of 1,3-dienes (B-blocks), preferably butadiene and isoprene, use. Both homo and copolymer blocks are usable according to the invention. resulting Block copolymers can contain the same or different B-blocks, partially, selectively or completely can be hydrogenated. Block copolymers can have linear A-B-A structure. Also usable are block copolymers of radial shape as well as star-shaped and linear multiblock copolymers. As further components, A-B two-block copolymers to be available. Block copolymers of vinylaromatics and isobutylene are also used according to the invention. All of the aforementioned polymers can used alone or in mixture with each other. Especially advantageous have block copolymers with a block polystyrene content of 20 to 30% by weight.

Instead of the polystyrene blocks and polymer blocks based on other aromatic-containing homo- and copolymers (preferably C ₈ - to C ₁₂ aromatics) with glass transition temperatures of> about 75 ° C can be used as for example α-methylstyrene-containing aromatic blocks. Likewise, polymer blocks based on (meth) acrylate homo- and (meth) acrylate copolymers with glass transition temperatures of> 75 ° C can be used. In this case, block copolymers can be used which use as hard blocks exclusively those based on (meth) acrylate polymers as well as those which use both polyaromatic blocks, for example polystyrene blocks, and also poly (meth) acrylate blocks.

Instead of styrene-butadiene block copolymers and styrene-isoprene block copolymers and their hydrogenation products, hence styrene-ethylene / butylene block copolymers and styrene-ethylene / propylene block copolymers can also be used according to the invention Block copolymers and their hydrogenation products are used, which use other polydiene elastomeric blocks, such as copolymers several different 1,3-dienes. Usable according to the invention are further functionalized block copolymers, such as maleic anhydride modified or silane-modified vinylaromatic block copolymers.

When other polymers can those based on pure hydrocarbons, for example unsaturated polydienes like natural or synthetically produced polyisoprene or polybutadiene, chemical essentially saturated Elastomers such as saturated Ethylene-propylene copolymers, α-olefin copolymers, Polyisobutylene, butyl rubber, ethylene-propylene rubber, and chemically functionalized hydrocarbons such as halogenated, acrylate-containing or vinyl ether-containing polyolefins are used, which up to a proportion of up to 100 phr based on the vinyl aromatic block copolymer can be present.

When Tackifiers use PSAs of the invention as the main component especially medium block compatible Resins with a softening point above 120 ° C, measured after the ring and Ball method.

Among others, hydrogenated and nonhydrogenated derivatives of rosin, polyterpene resins, preferably based on alpha-pinene, terpene-phenolic resins, non-crosslinking phenolic resins, novolaks, hydrogenated and non-hydrogenated polymers of dicyclopentadiene, hydrogenated and non-hydrogenated polymers of preferably C ₈ - and are particularly suitable C ₉ aromatics, hydrogenated C ₅ / C ₉ polymers and aromatically modified selectively hydrogenated Dicyclopentadienderivate. The aforementioned adhesive resins can be used both alone and in admixture.

adhesive resins with a softening point below 120 ° C (measured after the ring and Ball method) in formulations according to the invention in a weight proportion of 50 wt .-%, based on the total content at mittelblockverträglichen Resins, to be present.

Besides can also resins are used, which with the Vinylaromatenblöcken the Vinylaromatic block copolymers are compatible. Preferred here include resins based on pure aromatics such as alpha-methylstyrene, vinyltoluene or styrene or resins from mixtures of different aromatic monomers.

Also can be used coumarone-indene resins from the coal tar be won. Another class of useful resins are low molecular weight Polyphenylene oxides, which are particularly compatible with Styrolendblöcken in Styrene block copolymers.

Endblock compatible resins can up to a weight proportion of 25 wt .-% based on the total adhesive to be available.

When other additives can Typically used are primary antioxidants, such as Example of sterically hindered phenols, secondary antioxidants, such as Example phosphites or thioethers, process stabilizers, such as Example C radical scavenger, Light stabilizers, such as UV absorbers or sterically hindered Amines, antiozonants, metal deactivators and processing aids, just to name a few.

plasticizers, such as plasticizer oils or low molecular weight liquid Polymers, such as low molecular weight polyisobutylenes with Molar masses <1500 g / mol (number average), or liquid EPDM types are typically used in small amounts of <10% by weight.

fillers such as silica, glass (ground or in the form of Balls), aluminas, zinc oxides, calcium carbonates, calcium sulphates, Titanium dioxides, carbon blacks and color pigments, just to name a few, can also be used.

Of Further can the adhesive film in particular balls with metallic, ie conductive coating (for example Gold or silver) or metal-containing particles. The particles can be made of pure metal (gold, Silver), but can also be made of an alloy, which then becomes a considerable Share the metal should contain to ensure the conductivity. When in the Next of the metallized spheres (preferably of glass) the Speech is, he knows Specialist that mentioned these Particles should always be read.

Around It can prevent excessive deformation of the adhesive film Cheap be admixing Spacerpartikel, in a proportion of 1 to 10 wt .-%. The Spacerpartikel are of particular spherical Geometry and made of a hard material, which at the increased bonding temperature does not melt and is difficult or not deformable. The spacer particles can also conductive But they should be harder its as the metallized particles. Furthermore, they should have a smaller one Diameter than the conductive ones Have particles.

The thickness of the Spacerpartikel corresponds approximately to the desired thickness of the adhesive layer after the pressing or bonding. They thus have a diameter which is slightly smaller than the thickness of the adhesive film. They allow a precise adjustment of this thickness by the bonding process under temperature, pressure and the plane parallelism of the plunger, even if these bonding parameters vary. The spacers mentioned are preferably spherical hard particles such as glass beads. A metal layer on these balls is possible, but not necessary because the possibly additionally present soft metallized particles cause sufficient conductivity and thus already a conductive system is present.

• i) eines oder mehrere Vinylaromatenblockcopolymere, wobei der Gesamtanteil der Vinylaromatenblockcopolymere an der Klebmasse beträgt 20 Gew.-% bis 75 Gew.-%, bevorzugt 30 Gew.-% bis 70 Gew.-%, besonders bevorzugt 40 Gew.-% bis 60 Gew.-%, und
• ii) eines oder mehrere endblockverträgliche Harze mit einem Anteil von 25 Gew.-% bis 70 Gew.-%.

In a further advantageous embodiment, the heat-activatable adhesive film contains at least the following constituents:

• i) one or more vinylaromatic block copolymers, wherein the total proportion of vinylaromatic block copolymers in the adhesive is from 20% by weight to 75% by weight, preferably from 30% by weight to 70% by weight, particularly preferably from 40% by weight to 60 Wt .-%, and
• ii) one or more endblock compatible resins at a level of from 25% to 70% by weight.

While at Adhesive bonding medium-compatible Resins for the stickiness and the endblock compatible resins mainly for Increase in cohesion and improved thermal stability heat-activatable systems provide the endblock compatible Resins for one Stickiness at elevated Temperatures resulting in a very high bonding performance. The bond strengths can through skillful selection of resins those of thermoplastic systems to reach. Advantageous is the ease of processing both from solution as well as from the melt.

• i) eines oder mehrere Vinylaromatenblockcopolymere und
• ii) mindestens ein Reaktivharz.

In a further advantageous embodiment, the heat-activatable adhesive film contains at least the following constituents:

• i) one or more vinylaromatic block copolymers and
• ii) at least one reactive resin.

By the use of reactive resins enables secure bonding. Especially heat-reactive resins are preferred.

When Reactive resins are mainly phenolic resins and alkylphenol resins are used. The use concentration is in an advantageous embodiment at least 5 wt .-% based on the total adhesive. Prefers These resins are used in a concentration of 10 to 25% by weight. To significantly facilitate the crosslinking of the reactive resins, Oxides or salts of polyvalent metals are used, preferably Magnesium or zinc compounds used as oxides or salts of longer organic acids, for example as stearates. Other salts can be used.

to Further enhancement of high temperature crosslinking may be co-catalysts such as For example, bromobutyl rubber or chlorosulfone rubber used to name just a few.

• a.) ein thermoplastisches Polymer mit einem Anteil von zumindest 30 Gew.-%,
• b.) ein oder mehrere klebrigmachende Harze mit einem Anteil von 5 bis 50 Gew.-% und/oder
• c.) Epoxidharze mit Härtern, gegebenenfalls auch Beschleunigern, mit einem Anteil von 5 bis 40 Gew.-%,
• d.) gegebenenfalls metallisierte Partikel mit einem Anteil von 0,1 bis 40 Gew.-%, besonders bevorzugt 10 Gew.-%,
• e.) gegebenenfalls nur schwer oder nicht verformbare Spacerpartikel mit einem Anteil von 1 bis 10 Gew-%, die bei der Verklebungstemperatur der Klebefolie nicht schmelzen.

In addition to the reactive resins, the adhesives used may also contain the adhesive resins customary for the compounding of vinylaromatic block copolymers. For example, certain rosin, hydrocarbon and coumarone resins have proven to be suitable resins. In a further advantageous embodiment, the heat-activatable adhesive film contains at least the following constituents:

• a.) a thermoplastic polymer in a proportion of at least 30 wt .-%,
• b.) one or more tackifying resins in a proportion of 5 to 50 wt .-% and / or
• c.) epoxy resins with hardeners, optionally also accelerators, in a proportion of 5 to 40 wt .-%,
• d) optionally metallized particles in a proportion of 0.1 to 40 wt .-%, particularly preferably 10 wt .-%,
• e.) optionally difficult or not deformable spacer particles in a proportion of 1 to 10% by weight, which do not melt at the bonding temperature of the adhesive film.

The Elastomer is preferably selected from the group of polyolefins, polyester, Polyurethanes or polyamides or may be a modified rubber such as nitrile rubber or polyvinyl butyral, Polyvinyl formal, polyvinyl acetate, carboxylated or epoxylated SEES polymer.

By the chemical cross-linking reaction (based on epoxides or phenolic resin condensation) the resins at elevated Temperature will be great Strengths between the adhesive film and the surface to be bonded achieved and achieved a high internal strength of the product.

The Addition of the reactive resin / hardener systems leads as well to a lowering of the softening temperature of the above Polymers, what their processing temperature and speed advantageous lowers. The suitable product is one at room temperature or slightly increased Temperature self-adhesive product. When heating the product it comes in the short term also to a lowering of the viscosity whereby the product also has rough surfaces can wet.

• a) ein säure- oder säureanhydridmodifizierten Acrylnitril-Butadien-Copolymer und
• b) ein Epoxidharz und/oder ein Reaktivharz, wie bereits oben beschrieben,

wobei das Gewichtsverhältnis der beiden Komponenten a/b größer als 1,5 ist und wobei kein zusätzlicher nicht polymerer Härter eingesetzt wird.In a further advantageous embodiment, the heat-activatable adhesive film contains at least the following constituents:

• a) an acid or acid anhydride modified acrylonitrile-butadiene copolymer and
• b) an epoxy resin and / or a reactive resin, as already described above,

the weight ratio of the two compo nenten a / b is greater than 1.5 and wherein no additional non-polymeric curing agent is used.

• a) ein Acrylnitril-Butadien-Copolymeren mit einem Gewichtsanteil von 40 bis 80 Gew.-%,
• b) ein Polyvinylacetal mit einem Gewichtsanteil von 2 bis 30 Gew.-%,
• c) ein Epoxidharz mit einem Gewichtsanteil von 10 bis 50 Gew.-% und
• d) ein Härter,

wobei die Epoxidgruppen bei hohen Temperaturen mit dem Härter chemisch vernetzt werden.In a further advantageous embodiment, the heat-activatable adhesive film contains at least the following constituents:

• a) an acrylonitrile-butadiene copolymer having a weight fraction of 40 to 80% by weight,
• b) a polyvinyl acetal having a weight fraction of from 2 to 30% by weight,
• c) an epoxy resin with a weight fraction of 10 to 50 wt .-% and
• d) a hardener,

wherein the epoxy groups are chemically crosslinked at high temperatures with the curing agent.

When Nitrile rubbers can In particular, all acrylonitrile-butadiene copolymers are used with an acrylonitrile content of 15 to 50 wt .-%. Likewise, too Copolymers of acrylonitrile, butadiene and isoprene can be used. there is the proportion of 1,2-linked butadiene variable. The aforementioned polymers can be different The degree of hydrogenation is also complete hydrogenated polymers having a double bond content of less than 1% available.

All these nitrile rubbers are carboxylated to some extent, Preferably, the proportion of acid groups at 2 to 15 wt .-%. For example, such systems are commercial available under the name Nipol 1072 or Nipol NX 775 from Zeon. Hydrogenated carboxylated nitrile rubbers are known as Therban XT VP KA 8889 commercialized by Lanxess.

With Polyvinyl acetals are all acetals as polyvinyl derivatives, So also polyvinyl or polyvinyl butyral, with different Contents of polyvinyl alcohol, and preferably obtained polyvinyl butyrals made of polyvinyl alcohol. The content of polyvinyl alcohol can be vary between 5 and 40 wt .-%. Polyvinyl butyrals are preferred since they are much easier in solution to get to. Both the nitrile rubbers and the polyvinyl butyrals can be found in short-chain alcohols and ketones such as ethanol or Dissolve butanone. Butanone is preferred because the remaining components, especially better dissolve the epoxy resins in butanone.

Epoxy resins are usually understood as meaning both monomeric and oligomeric compounds having more than one epoxide group per molecule. These may be reaction products of glycidic esters or epichlorohydrin with bisphenol A or bisphenol F or mixtures of these two. It is also possible to use epoxy novolak resins obtained by reaction of epichlorohydrin with the reaction product of phenols and formaldehyde. Also, monomeric compounds having multiple epoxide end groups used as thinners for epoxy resins are useful. Also elastically modified epoxy resins can be used. Examples of epoxy resins are Araldite ^™ 6010, CY-281 ^™ , ECN ^™ 1273, ECN ^™ 1280, MV 720, RD-2 from Ciba Geigy, DER ^™ 331, 732, 736, DEN ^™ 432 from Dow Chemicals, Epon ^™ 812, 825, 826, 828, 830 etc. from Shell Chemicals, HPT ^™ 1071, 1079 also from Shell Chemicals, Bakelite ^™ EPR 161, 166, 172, 191, 194 etc. from Bakelite AG.

commercial Aliphatic epoxy resins are, for example, vinylcyclohexanedioxides such as ERL-4206, 4221, 4201, 4289 or 0400 from Union Carbide Corp.

elasticized Epoxy resins are available from the company Noveon under the name Hycar.

Epoxy thinners, monomeric compounds having plural epoxy groups are, for example, Bakelite ^TM KR EPD EPD Z8, EPD HD, EPD WF, etc. from Bakelite AG or Polypox ^TM R9, R12, R15, R19, R20, etc. of the company UCCP.

Further preferably contains the adhesive film more than an epoxy resin.

In addition to the acid or acid anhydride modified nitrile rubbers already mentioned, other elastomers can also be used. Besides other acid- or acid-anhydride-modified elastomers, it is also possible to use unmodified elastomers, for example polyvinyl alcohol, polyvinyl acetate, styrene block copolymers, polyvinyl formal, polyvinyl butyral or soluble polyesters. It is also possible to use copolymers with maleic anhydride, for example a copolymer of polyvinyl methyl ether and maleic anhydride, for example available under the name Gantrez ^™ , marketed by ISP.

By the chemical crosslinking of the resins with the elastomers becomes very much size Strengths within the adhesive film achieved.

Around the adhesion to increase, It is also possible to add adhesive resins compatible with the elastomer.

As tackifiers, non-hydrogenated, partially or fully hydrogenated resins based on rosin and rosin derivatives, hydrogenated polymers of dicyclopentadiene, non-hydrogenated, partially, selectively or completely hydrogenated hydrocarbon resins based on C ₅ -, C ₅ / C, for example, can be used in PSAs of the invention ₉ or C ₉ monomer streams, polyterpene resins on Ba sis of α-one and / or β-pinene and / or δ-limonene, hydrogenated polymers of preferably pure C ₈ and C ₉ aromatics are used. The aforementioned adhesive resins can be used both alone and in admixture.

• • primäre Antioxidanzien, wie zum Beispiel sterisch gehinderte Phenole
• • sekundäre Antioxidanzien, wie zum Beispiel Phosphite oder Thioether
• • Prozessstabilisatoren, wie zum Beispiel C-Radikalfänger
• • Lichtschutzmittel, wie zum Beispiel UV-Absorber oder sterisch gehinderte Amine
• • Verarbeitungshilfsmittel
• • Füllstoffe, wie zum Beispiel Siliziumdioxid, Glas (gemahlen oder in Form von Kugeln), Aluminiumoxide, Zinkoxide, Calciumcarbonate, Titandioxide, Ruße, Metallpulver, etc.
• • Farbpigmente und Farbstoffe sowie optische Aufheller

As further additives can typically be used:

• • primary antioxidants, such as sterically hindered phenols
• • secondary antioxidants, such as phosphites or thioethers
• • Process stabilizers, such as C radical scavengers
• • Sunscreens, such as UV absorbers or hindered amines
• • processing aids
• Fillers, such as silica, glass (milled or in the form of spheres), aluminas, zinc oxides, calcium carbonates, titanium dioxides, carbon blacks, metal powders, etc.
• • Color pigments and dyes as well as optical brighteners

By the use of plasticizers can increase the elasticity of the crosslinked adhesive elevated become. As a plasticizer can while, for example, low molecular weight polyisoprenes, polybutadienes, Polyisobutylenes or polyethylene glycols and polypropylene glycols be used.

There the nitrile rubbers used, even at high temperatures no have too low viscosity, it usually happens during gluing and hot pressing not to the exit of the adhesive from the glued joint. During this Process crosslink the epoxy resins with the elastomers, it gives a three-dimensional network.

By the addition of so-called accelerators can further increase the reaction rate elevated become.

• 1. Mono- und Diurone
• 2. tertiäre Amine, wie Benzyldimethylamin, Dimethylaminomethylphenol, Tris(dimethylaminomethyl)phenol
• 3. Bortrihalogenid-Amin-Komplexe
• 4. substituierte Imidazole
• 5. Triphenylphosphin

Accelerators can be for example:

• 1. Mono- and Diurons
• 2. Tertiary amines, such as benzyldimethylamine, dimethylaminomethylphenol, tris (dimethylaminomethyl) phenol
• 3. Boron trihalide-amine complexes
• 4. substituted imidazoles
• 5. triphenylphosphine

The Formulation "not Completely networked "means in the sense of this invention, that the chemical reaction during the Process of hot curing not completely expires, so that the adhesive film is even softer and more elastic than a completely cured Movie. The degree of curing can be determined by a so-called DSC analysis, a abbreviation for "Differential Scanning Calorimetry" DSC analysis is called "ISO 11 357, Parts 1-5 of 1999 ". To determine the degree of cure are a small sample of the adhesive film from the curing process and an uncured comparative sample heated and the needed heat recorded in the form of curves. Existing chemical reaction potential shows an exothermic reaction peak, which is in relation to Comparative peak can be quantitatively evaluated.

In According to a further advantageous embodiment, the heat-activatable used is Adhesive film resistant to the usual cleaning and pretreatment processes, media used in coachbuilding conditions, in particular with regard to degreasing, activation, phosphating and passivation.

Prefers the cross-linkable adhesive film has a characteristic activation temperature of at least 40 ° C, more preferably at least 80 ° C. This prevents possible reactions already during storage or on the transport.

On the other hand, the lowest possible activation temperatures are desirable, in particular in order to achieve a sufficient initial strength at short cycle times. Adhesive films are preferred which have an initial strength of more than 1 MPa according to DIN EN 1465 (substrate: aluminum plates 100 × 20 × 1.6 mm ³⁾ even at an activation temperature of not more than 130 ° C., particularly preferably not more than 110 ° C. , etched, bond area 20 mm ² , test speed 10 mm / min).

The Activation time to achieve the initial strength is preferred less than 1 minute, more preferably less than 30 seconds, especially preferably less than 10 s.

Prefers the films are not at temperatures below 60 ° C or only slightly sticky, so that the film can be easily positioned can. The bond strength at room temperature according to ASTM D 3330-04 (auf polished steel at a withdrawal speed of 300 mm / min) is preferably less than 3 N / cm, more preferably less than 1 N / cm.

Strengths of more than 8 MPa are particularly advantageously achieved in the tensile shear test according to DIN EN 1465 (substrate: aluminum plates 100 × 20 × 1.6 mm ³ , etched, bonding area 20 mm ² , test speed 10 mm / min) after curing.

The adhesion is in an advantageous embodiment of the adhesive film on oiled sheets. Further preferably, the adhesive film reaches a strength of more than 4 MPa in the tensile shear test according to DIN EN 1465 (bond area 20 mm ² , test speed 10 mm / min) on said oiled body panels.

The Heating of the adhesive film at the point of adhesive is done by any known to the expert form of heat generation and supply, in particular by heat conduction. These are for example the Bolt and / or the body panel heated up before and / or during the Bolt with the intervening foil and the body sheet is pressed. The required heat can also be, for example through the use of ultrasound, high-energy radiation, heating elements or introduced by friction.

Prefers is already on reaching a sufficient initial strength the pressing force is lifted, so that the cycle times are shortened.

A postcure the adhesive bond by the thermal drying is advantageously along with the curing the body paint made in the painting oven. This allows the Cycle time when applying the fastener (bolt) are shortened, since the achievement of the required final strength is not awaited here must become. It is also particularly advantageous, the heat already while of the lead of the bolt and / or the adhesive film to the bonding point the fastener (Bolt) and / or the joining partner and / or to supply the adhesive film, to shorten the cycle times further.

In an advantageous embodiment of the method, the fastening element and / or the body panel is heated by induction and thus heat is conducted into the adhesive film. Particularly preferred frequencies of 10 to 2000 kHz are used. Corresponding devices are in DE 196 38 521 A1 and DE 10 2004 012 786 A1 described.

Prefers is by punching or otherwise shaping the adhesive film adapted in their geometry exactly the bond area.

In a further advantageous embodiment of the process, the adhesive sheet is applied to the surface of the fasteners prelaminated, wherein the lamination temperature is below the crosslinking temperature. This facilitates the placement of the bolt and the adhesive film the body. The so equipped Fasteners offer the great advantage of being up to Use of the fasteners are tack-free and that only by the activation of the prelaminated adhesive film at the place of use inherent adhesive power is released, which is practically one unsolvable Connection leads.

Farther advantageous is the use of a robot for placing, heating and pressing the component, in particular a prefabricated with adhesive film Fastener.

in the Below, the invention will be explained in more detail with reference to several examples, without limiting in any way to be effective.

Examples

Example 1: Preparation of a Heat-Activatable adhesive film

A heat-activatable adhesive film of the following composition was produced:
30 parts by weight Granulated nitrile rubber
19 parts by weight Natural rubber granulated
30 parts by weight Phenol resin
12 parts by weight alkylphenol
6 parts by weight Hexamethylenetetramine (HMTA)
3 parts by weight talc

Procedure in the production

The talc-powdered rubber granules were co-packed with 100 Parts by weight of a mixture of equal parts of methyl ethyl ketone and toluene homogenized in a kneader for 10 hours. Subsequently were the resins and the HMTA added and joined in.

The so produced adhesive was by means of a doctor blade on a release paper streaked and in a convection oven or drying channel at 90 to 100 ° C to a Adhesive film dried.

Example 2: Preparation of an electrodeposition paint

The preparation of the electrodeposition paint used for test purposes can be, for example, the disclosure of US 4,920,162 A be removed.

Example 3:

• 1. Applikation eines Abschnitts der hitzeaktivierbaren Klebefolie zwischen der Oberlappungsfläche zweier oberflächengeätzter Aluminium-Streifen der Dimensionen 100 × 20 × 1.6 mm³, wobei sich die Streifen an ihrem Ende um 10 mm überlappten, so dass sich eine Verklebungsfläche von 20 mm² ergab
• 2. Aufheizen der Fügeteilanordnung mittels einer Heizpresse auf 180°C unter einem Druck von 0.5 MPa
• 3. Aufrechterhalten des Anpressdrucks und der Temperatur über eine Zeit von 20 s
• 4. Entfernen der Anpressvorrichtung und Abkühlen der Klebverbindung
• 5. KTL-Lackierung mit dem Lack aus Beispiel 2 bei einer Spannung von 300 V und einer Badtemperatur von 30°C über eine Zeit von 15 min
• 6. Wiederaufheizen der Klebeverbindung in einem Ofen ohne Anpressdruck auf 180°C
• 7. Aufrechterhalten der Temperatur über 30 min
• 8. Abkühlen der Klebverbindung

A process according to the invention was carried out using the heat-activatable adhesive film from Example 1 in the following steps:

• 1. Applying a portion of the heat-activatable adhesive film between the top surface of two surface-etched aluminum strips of dimensions 100 × 20 × 1.6 mm ³ , wherein the strips overlap at their end by 10 mm, so that a bond area of 20 mm ² resulted
• 2. Heating the Fügeeteilanordnung by means of a hot press to 180 ° C under a pressure of 0.5 MPa
• 3. Maintaining the contact pressure and the temperature over a period of 20 s
• 4. Remove the pressing device and cool the adhesive bond
• 5. KTL coating with the paint of Example 2 at a voltage of 300 V and a bath temperature of 30 ° C over a period of 15 min
• 6. Reheat the adhesive bond in an oven without contact pressure to 180 ° C.
• 7. Maintain the temperature over 30 min
• 8. cooling the adhesive bond

To Step 4 was the initial strength of the adhesive bond according to DIN EN 1465 (test speed 10 mm / min) tested. There was a value of 2.3 MPa.

To Step 5 also became the strength of the bond after DIN EN 1465 (test speed 10 mm / min) tested. There was a value of 2.6 MPa.

To Step 8 also became the strength of the bond after DIN EN 1465 (test speed 10 mm / min) tested. There was a value of 16.2 MPa.

to exam possible contamination of the cathodic dip bath with extracts of the not fully crosslinked Adhesive film, strips of the film were freed from release paper, 15 in the magnetic stirrer for min immersed KTL bath immersed, then rinsed and dried again. By gravimetric determination (weighing before and after) it was demonstrated that no weight loss had taken place. This could be done by analyzing the bath composition approved become.

Example 4:

• 1. Applikation eines Abschnitts der hitzeaktivierbaren Klebefolie zwischen der Überlappungsfläche zweier Streifen ST 37 der Dimensionen 100 × 20 × 0,8 mm³, wobei sich die Streifen an ihrem Ende um 10 mm überlappten, so dass sich eine Verklebungsfläche von 20 mm² ergab Einer der Streifen war zuvor mit Tiefziehöl Oest Platinol K103 überzogen und mit einem Zellstofftuch abgewischt worden. Der zweite Streifen war mit Aceton gereinigt worden.

A process according to the invention was carried out using the heat-activatable adhesive film from Example 1 in the following steps:

• 1. Application of a section of the heat-activatable adhesive film between the overlapping surface of two strips ST 37 of dimensions 100 × 20 × 0.8 mm ³ , the strips overlapping at their end by 10 mm, so that a bond area of 20 mm ² resulted The strip had previously been coated with deep-drawing oil Oest Platinol K103 and wiped with a tissue cloth. The second strip had been cleaned with acetone.

• 5. Die Prüfkörper wurden dann einem Automobillackierungsprozess gemäß 1 einschließlich der Vorbehandlungsschritte Entfetten, Aktivieren, Phosphatieren, Passivieren und KTL-Lackierung und deren Aushärtung (180°C, 20 min) unterzogen, indem sie an einer Rohkarosserie befestigt wurden, die diesen Prozess durchlief.

Steps 2 to 4 were carried out according to Example 1.

• 5. The specimens were then subjected to an automotive painting process according to 1 including the pre-treatment steps degreasing, activating, phosphating, passivating and cathodic painting and curing them (180 ° C, 20 min) by attaching them to a body shell that went through this process.

To Step 4 was the initial strength of the adhesive bond according to DIN EN 1465 (test speed 10 mm / min) tested. There was a value of 1.9 MPa.

To Step 5 was the strength of the adhesive bond according to DIN EN 1465 (Test speed 10 mm / min) tested. There was a value of 13.6 MPa.

Example 5:

• 1. Zurverfügungstellung entsprechend der Verklebungsfläche vorgestanzter Klebefolien auf einem Trägerpapier in Rollenform
• 2. Vorheizen eines Bolzens mit Tellerfuß auf eine Temperatur von 100°C
• 3. Abnahme eines Stanzlings mittels des vorgeheizten Befestigungselements vom Trägerpapier (durch die Temperierung haftet der Stanzling am Bolzen)
• 4. weiteres Aufheizen des Befestigungselements mit anhaftender Klebefolie auf 160°C
• 5. Anpressen des Befestigungselements mit anhaftender Klebefolie an den Fügepartner
• 6. Aufrechterhalten des Anpressdrucks und der Temperatur über eine Zeit von 20 s
• 7. Entfernen der Anpressvorrichtung und Abkühlen der Klebverbindung
• 8. Wiederaufheizen der Klebeverbindung in einem Ofen ohne Anpressdruck auf 160°C
• 9. Aufrechterhalten der Temperatur über 20 min
• 10. Abkühlen der Klebverbindung

In order to bond a pin with a disc root (d = 20 mm), the method according to the invention was likewise carried out using the heat-activatable adhesive sheet of Example 1 in the following steps:

• 1. Provision according to the bonding surface of prepunched adhesive films on a carrier paper in roll form
• 2. Preheat a bolt with a disc base to a temperature of 100 ° C
• 3. Removal of a stamped product by means of the preheated fastener from the backing paper (due to the tempering of the stamped product adheres to the bolt)
• 4. further heating of the fastener with adhering adhesive film to 160 ° C.
• 5. Pressing the fastener with adhering adhesive film to the joining partner
• 6. Maintaining the contact pressure and the temperature over a period of 20 s
• 7. Remove the pressing device and cool the adhesive bond
• 8. Reheat the adhesive bond in an oven without contact pressure to 160 ° C
• 9. Maintain temperature for 20 min
• 10. Cooling of the adhesive bond

It It was found that components laminated with the adhesive film on this way can be.

In an advantageous embodiment of the method, steps 1 to 3 are already at the manufacturer performed the fasteners and the element with the Adhesive film then cooled. The user of the fasteners then performs only the steps 4 to 10 by.

Based In the following figures, the invention will be clarified without departing from in some way limiting to be effective.

2 shows by way of example four different embodiments of glued components.

3 shows a fastener ( 2 ), which by means of a heat-activated adhesive film ( 1 ) on a joint partner ( 3 ) is glued.

Claims (15)

Method for fixing a component on a to be painted joint partners, wherein the component is connected to a portion of a non-fully crosslinked heat-activated Adhesive film on the joining partner is fixed the joining partner painted together with the component fixed on it, the varnished joining partner together with the component fixed on it in a thermal drying process is dried, wherein the thermal energy to complete crosslinking The heat-activatable adhesive film leads so that the component permanently on the joining partner is fixed. Method according to claim 1, characterized in that that the joining partner is made of metal, preferably a body of a vehicle. Method according to claim 1 or 2, characterized that the adhesive film on the surface of the fastener prelaminated, the lamination temperature below the starting temperature the networking lies. Method according to at least one of claims 1 to 3, characterized in that the heat-activatable adhesive film resistant to the usual cleaning, pretreatment, anti-corrosive and painting processes, media and conditions is, in particular across from across from degreasing, activation, passivation of phosphating and / or anodic and cathodic dip painting. Method according to at least one of the preceding claims, characterized characterized in that the thermal drying in a subsequent temperature-charged process is carried out, in particular along with the curing of the paint in the painting oven. Method according to at least one of the preceding claims, characterized characterized in that the energy for the thermal drying already during of the lead of the bolt and / or the adhesive film to the bonding point the fastener and / or the joining partner and / or the adhesive film fed becomes. Method according to at least one of the preceding claims, characterized characterized in that the activation time to reach the not fully networked State less than 1 minute, more preferably less than 30 seconds, most preferably less than 10 s. Method according to at least one of the preceding claims, characterized characterized in that the not completely cross-linked adhesive film the Painting process or the media used therein is not affected, in particular not a phosphating or KLT bath. Method according to at least one of the preceding claims, characterized in that the adhesive film has a thickness of 10 to 250 μm, especially 50 up to 200 μm having. Method according to at least one of the preceding claims, characterized in that the crosslinkable adhesive film has a characteristic Activation temperature of at least 40 ° C, more preferably of at least 80 ° C has. Method according to at least one of the preceding claims, characterized in that the adhesive film has a strength of more than 8 MPa in the tensile shear test according to DIN EN 1465 (substrate: aluminum plates 100 × 20 × 1.6 mm ³ , etched, bond area 20 mm ² , Test speed 10 mm / min) and / or a strength of more than 4 MPa in the tensile shear test according to DIN EN 1465 (bond area 20 mm ² , test speed 10 mm / min) on oiled body panels achieved. Method according to at least one of the preceding claims, characterized in that the adhesive film at an activation temperature of not more than 130 ° C, more preferably not more than 110 ° C, an initial strength of more than 1 MPa according to DIN EN 1465 (substrate: aluminum Plates 100 × 20 × 1.6 mm ³ , etched, bonding area 20 mm ² , activation time 20 s, test speed 10 mm / min). Method according to at least one of the preceding claims, characterized characterized in that the adhesive force of the adhesive film at room temperature according to ASTM D 3330-04 (at a take-off speed of 300 mm / min) preferably less than 3 N / cm, more preferably less than 1 N / cm is. Method according to at least one of the preceding claims, characterized characterized in that by punching or otherwise shaping the adhesive film exactly matches the bonding surface in terms of its geometry is. Method according to at least one of the preceding claims, characterized characterized in that a robot for placing, heating and pressing the Fastening element and / or the adhesive film is used.