WO2007140870A1

WO2007140870A1 - Layer-like reinforcing component

Info

Publication number: WO2007140870A1
Application number: PCT/EP2007/004473
Authority: WO
Inventors: Karl Wesch; Matthias JÄHNICHEN; Jochen Becker
Original assignee: Henkel Ag & Co. Kgaa
Priority date: 2006-06-09
Filing date: 2007-05-18
Publication date: 2007-12-13
Also published as: DE102006027231A1; EP2027195A1

Abstract

Layer-like reinforcing component containing a sheet-like structure as support material on which a high-strength thermally expandable and curable adhesive layer and parallel thereto a contact-adhesive adhesive layer are located, with the support material preferably having a rectangular shape and the contact-adhesive adhesive and the thermally expandable and curable adhesive layer being arranged as flat rectangular or contoured extrudates as parallel strips on the support material. Method of stiffening and/or reinforcing bodywork components by incorporation of such a reinforcing component.

Description

"Laminated reinforcing member"

The invention relates to a layered reinforcing member based on a sheet as a carrier material and a thermally expandable and curable adhesive layer, and a method for stiffening and / or reinforcing body components.

Triggered by improved corrosion protection for metallic substrates, easier moldability of these thin substrates and lower costs, and in particular because of the weight savings and the associated savings in fuel in the operation of such lightweight vehicles, has the use of thin strips, plates or sheets in vehicle construction in the recent Time increased. In the past, either stiffening metallic plates were welded or glued to the thin sheets for stiffening. Because of the aforementioned weight saving requirement, the demand for light weight stiffening, frame stiffening or cavity stiffening systems for a wide variety of automotive applications is very high. So far, moldings based on epoxy resins, polyurethanes and / or other thermally curable binder compositions have been known for these applications in addition to the aforementioned metal plates.

EP-A-298024, for example, describes a method for stiffening sheet metal and plastic moldings with the aid of a single-layer or multi-layer planar stiffening body which has at least one layer of a thermosetting resin. This stiffening body is initially subjected to a first heat treatment, in which at least one surface of the stiffening body becomes tacky by this first heat treatment. Subsequently, the stiffening body with the sticky surface is to be applied to the element to be stiffened and then the stiffening body is to be subjected to a second heat treatment until all layers of the stiffening body have cured. It is proposed that a layer of the reinforcing body is constructed of thermosetting epoxy resins and optionally contains glass fiber fabric. As second Layer which is to become tacky in the first heat treatment, an epoxy-based, possibly polyurethane or copolyester-based hot melt adhesive is proposed. Alternatively, this layer is to consist of a thermally shrinking film, so that after shrinkage, a sticky layer is exposed.

EP 0053361 A1 describes an adhesive layer material for reinforcing metal sheets comprising a first epoxy resin layer and a second epoxy resin layer laminated to the first epoxy resin layer, the first epoxy resin layer having a modulus of elasticity sufficient to allow stiffening of a metal plate after curing whereas the second epoxy resin layer after curing by heating should have an modulus of elasticity which is insufficient to cause stiffening of the metal plate to be stiffened. This is intended to cause the stress occurring due to the shrinkage in the curing of the high-modulus layer to be reduced, so that the warpage of the surface of the metal layer to be stiffened is reduced.

WO 99/50057 proposes a three-layer stiffening material which is made up of two polymer layers and one stiffening layer. In this case, the polymer layer facing the substrate to be stiffened should be a flexible foam layer after curing, while the outer layer arranged on the flexible foam layer is a layer of rigid foam. The third layer should be a film or fiberglass layer or a backing to effect additional stiffening. According to the teaching of this document, the stress caused by the shrinkage of the hard layer during curing should be kept away from the substrate to be stiffened by this layer arrangement.

Surface stiffening agents are also known from WO2004 / 039577. There are described multilayer laminates of at least two thermally curable binder layers and two layers of textile fabrics, which should be suitable for stiffening sheet-like substrates. The multilayer system is intended to include a binder layer facing the substrate to be stiffened, followed by a fibrous textile fabric layer on which a second binder layer is disposed. In turn, a second fiber-containing textile fabric layer is applied to this second binder layer. In the cured state, the binder layer facing the substrate to be stiffened is adhesively bonded to the substrate to be stiffened, and is intended to have either a same or a lower modulus of elasticity have as the second binder layer facing away from the substrate to be stiffened. Such multilayer laminates are suitable according to the teaching of this document for the marking-free stiffening of thin-walled substrates, in particular large-scale parts in vehicle construction such as doors, roof parts, engine compartment covers, trunk lids and the like.

Frame stiffening or cavity stiffening systems usually contain metallic or plastic supports and a thermally expandable and curable binder system or are formed as a strapless molded body directly from the thermally expandable and curable binder. They are usually fastened during a suitable process step with mechanical fasteners in the cavity still open at that time. Such stiffening foamable reinforcing members are described, for example, in the following references: US4901500, US4908930, US4751249, US4978562, US4995545, US5124186, US5575526, US5755486, US4923902, US4922596, US4861097, US4732806, US4695343, US4610836, US6068424, US6058673, US6003274, US5992923, US5888600, US6092864, US6079180 and US5884960.

The aforementioned reinforcing components generally comprise dry, non-adhesive parts, which are introduced with a retaining clip in the body cavities and mechanically fixed there.

Reinforcement components are also known, which are constructed on self-adhesive structural foam formulations and which are often provided with a fabric film in order to increase the buckling resistance and buckling strength. In a further application, which is preferably used to build a sandwich connection between 2 sheet metal surfaces, one uses melt films as a cover layer for better applicability.

However, the previously known state of the art for stiffening thin substrates solves the problem of warping the thin-walled sheet metal or plastic components by the shrinkage of the stiffening layers only insufficient, so that these marginal distortions and bumps in uniform and glossy painted components always bothersome , Especially in area applications in the visible range, you may find the problem of marking on the visible side of the application area ("read-through effect") Reinforcing foam introduces a softer underlayer, which does not resist the sheet expansion in the cooling phase as the high-strength structural foams. Also, by differently shaped edge lines, the tendency to delineate can be reduced. Another possibility are so-called multi-layer laminates with geometrically non-superimposed marginal lines in order to avoid or at least reduce the markings. Such a procedure is proposed, for example, in the aforementioned WO 2004/039577.

In view of this state of the art, the inventors have set themselves the task of providing reinforcing components, which can be connected to a component without mechanical Verklippsung on high-strength and crashrelevanten reinforcing plates or outer panels and at the same time prevent Abzeichnungsprobleme.

The achievement of the object of the invention can be found in the claims.

It consists essentially in the provision of a layer-shaped reinforcing member which contains a sheet as a carrier material on which a high-strength, thermally expandable and curable adhesive layer and parallel thereto a contact-sticky adhesive layer is arranged.

The carrier material is preferably a flexible to low-strength textile fabric made of glass fibers, polyamide fibers, carbon fibers, steel fibers or aluminum fibers. Particularly preferred are textile fabrics of glass fibers or polyamide fibers.

In a further embodiment, the carrier material (sheet) may be a plastic film of polyamide, polyimide, polyester or else a metal foil of steel, aluminum or copper. The film thickness of this support material is usually 0.05 to 3 mm, preferably the film thickness is between 0.1 and 1 mm.

The contact adhesive layer is built up on rubber compositions. This is preferably a butyl rubber. A particularly preferred contact-sticky material based on butyl rubber is available under the trade name Terostat ^R 81 from Henkel.

The thermally expandable and curable adhesive layer contains at least one liquid reactive epoxy resin, optionally a solid reactive epoxy resin, optionally a flexibilizer, optionally a reactive diluent, if necessary finely divided thermoplastic polymer powder. Furthermore, this composition contains hardeners and / or accelerators and blowing agents. Such thermally expandable curable adhesive compositions suitable for the reinforcing component according to the invention are described, for example, in WO 00/52086 or in WO 2003/054069.

The reinforcing components according to the invention will be explained in more detail with reference to some drawings. Show it:

Fig. 1 shows the basic layer structure of carrier material and the two adhesive layers

2 shows a section through a hollow component, in particular a section through a

Roof rail of a motor vehicle,

3 is a plan view of the reinforcing member according to the invention,

Fig. 4 is a plan view of a further embodiment of the invention

Gain component,

5 shows a cross section through the reinforcing component according to FIG. 3.

Fig. 1 shows the basic layer structure of a reinforcing member according to the present invention. On the carrier material (1) a strip of a high-strength, thermally expandable and curable adhesive composition (2) is applied. On the side facing away from the carrier, a film of a non-sticky at room temperature melt film (3) is applied. Furthermore, the contact-sticky adhesive layer (4) is applied in strips on the carrier, which is protected by a protective film (5) during storage time from surface contamination.

2 shows a section through a body part to be stiffened. In the specific case, it is a cross section through a roof rail of a motor vehicle in a schematic representation. The roof rail is composed of 3 sheet metal profiles, the inner panel (6), which will face the passenger compartment of the motor vehicle, the stiffening plate (7) and the outer panel (8), which is positioned in the outer viewing area of the vehicle. At the points (9) and (9 ¹ ) the 3 plates are connected together in the final state. This can be done by mechanical joining such as flanging, spot welding or by gluing or by a combination of all 3 attachment methods. At the time of assembly of the body, the reinforcing component according to the invention, after removal of the protective film (5) with the aid of the contact-adhesive layer (4) at the predetermined location of the still available at this time the assembly intermediate plate (7) fixed. Subsequently, the outer panel (8) is joined, wherein the thermally expandable and curable adhesive layer (2) is guided to the correct position. In this state (not shown in FIG. 2), the thermally expandable and curable adhesive layer (2) has not yet expanded and has not cured, but rests with the carrier material (1) as an intermediate layer on the outer panel (8). In further manufacturing process, the adhesive layer (2) is thermally expanded and cured using the process heat of the paint oven for curing the electrodeposition paint, with an adhesive connection to the reinforcing plate (7) is effected. Thus, the adhesive layer (2) completely fills the gap between outer panel (8) and reinforcing panel (7). A read-through which would be visible on the outside of the outer sheet 8 is avoided in that the adhesive layer 2 has no rigid adhesive bond with the outer sheet 8 due to the carrier film 1 therebetween ,

3 shows a plan view of an embodiment according to the invention of the reinforcing component with a glass fiber fabric (1) as the carrier material and the strip of the contact-adhesive layer (4), which is not visible here, since it is covered by the protective film (5). Spaced parallel thereto, the strip of high strength thermo-expandable and curable adhesive (2) is extruded. This carries on its surface a molten film, which melts when heated in the cathodic oven, so that an adhesive connection of the adhesive layer (2) with the stiffening plate (7) can be ensured.

FIG. 4 shows a further special embodiment of the reinforcing component according to the invention, in which the high-strength, thermally expandable and curable adhesive layer (2) has been extruded in the middle onto the carrier (1) made of glass fiber fabric and spaced apart on both sides by a contact-sticky adhesive layer (4) is arranged, which is covered in each case with a protective film (5). Such an embodiment allows the positioning and fixing of the reinforcing member in special versions with 2 kontaktklebrigen strips (4) after removal of the protective films (5).

It may be expedient that both in the embodiment according to FIG. 3 and in the embodiment according to FIG. 4 the carrier material (1) is provided with apertures or slots in the space between high-strength adhesive layer (2) and contact-adhesive layer (4), to be more adaptable to sharp bends on the components due to greater flexibility. FIG. 5 shows a cross-sectional view of the reinforcing component according to the invention according to FIG. 3, perpendicular to the plan view shown in FIG. 3. The adhesive layer (2, 2 ') is in turn extruded onto the support (1). This is a special form of the adhesive layer, which is more strongly contoured on one side at the point (2 ') and thus deviates from the general rectangular cross section of the adhesive layer. Such a shape of the adhesive layer (2) allows an optimized adaptation and space filling of the gap between the outer plate (8) and the stiffening plate (7). The contact-sticky layer (4) is in turn covered with a protective film (5).

The reinforcing member according to the invention of contact adhesive, structurally strong high-strength foamable adhesive and fabric-shaped carrier allows the attachment of the reinforcing member to body components that do not allow Verklippsung, Verschweizung or other mechanical fastening. In addition, the foamable adhesive is shielded from the visible surface of the outer panel by the outer sheet and the expandable adhesive layer arranged carrier layer, so that no marks are made in the field of view of the outer panel. The contour of the adhesive layer can be optimally adapted to the requirements, d. H. it can be designed as a flat rectangular profile or as a contoured profile.

The reinforcing component according to the invention can be produced inexpensively by double extrusion of the high-strength adhesive layer (2) and, parallel to this, either the contact-adhesive adhesive layer (4) which is adjacent or at a corresponding distance. Both layers can be executed as flat rectangular extrudates or as contour extrudates, depending on requirements.

If there is no danger of contamination or incorrect assembly, it is also possible to dispense with a coating of the high-strength adhesive layer (2) with a melt-film layer (3).

Where it is technically and mechanically possible, can be dispensed with the contact-sticky adhesive layer (4) with protective film (5) and the support instead be fixed with mechanical Fixierhilfsmitteln such as the so-called "push pins" at the predetermined location of the cavity component.

Claims

claims

1. A layered reinforcing member containing a sheet as a carrier material on which a high-strength thermally expandable and curable adhesive layer and a contact-sticky adhesive layer is arranged parallel thereto.

2. reinforcing member according to claim 1, characterized in that the fabric is a textile fabric of glass fibers, polyamide fibers, carbon fibers, steel fibers or aluminum fibers.

3. reinforcing member according to claim 1, characterized in that the sheet is a plastic film made of polyamide, polyimide or polyester or a metal foil made of steel, aluminum or copper.

4. reinforcing member according to claim 3 characterized by a film thickness of 0.05 to 3 mm, preferably from 0.1 to 1 mm.

5. reinforcing member according to claim 1, characterized in that the contact-adhesive layer is based on rubber compositions, preferably based on butyl rubber.

6. reinforcing member according to claim 1, characterized in that the thermally expandable and curable adhesive layer at least one liquid reactive epoxy resin, optionally a solid reactive epoxy resin, optionally a flexibilizer, optionally a reactive diluent, optionally a finely divided thermoplastic polymer powder, hardener and / or accelerator and propellant.

7. reinforcing member according to claim 1, characterized in that the carrier material has a rectangular blank and the contact-sticky adhesive layer and the thermally expandable and curable adhesive layer are arranged as flat rectangular or contour extrudates as parallel strips on the carrier material.

8. reinforcing member according to at least one of the preceding claims, characterized in that the carrier material facing away from the surfaces of the adhesive layers are provided with a protective film or non-sticky at room temperature melt film.

9. reinforcing member according to at least one of the preceding claims, characterized in that the carrier material facing away from the surface of the contact-adhesive layer is provided with a protective film and the carrier material facing away from the surface of the thermally expandable and curable adhesive layer with a non-sticky at room temperature melt film.

10. reinforcing member according to at least one of the preceding claims, characterized in that the carrier material is provided in the space between the contact-adhesive strip of adhesive and the thermally expandable and curable adhesive strip with openings or slots.

11. A method for stiffening and / or reinforcing body components, wherein at least one reinforcing member according to at least one of the preceding claims introduces into the body component, characterized by the following essential method steps

a) removing the protective film from the contact-adhesive layer, b) positioning the reinforcing member at the predetermined location of the body panel, c) fixing the reinforcing member by pressure on the substrate in the area of the contact-adhesive layer, d) fitting the second body panel in the predetermined position, e ) Fixing the body components, f) heating to temperatures between 110 ⁰ C and 200 ⁰ C, preferably between 130 ⁰ C and 180 ° C, wherein the volume of the thermally expandable and curable adhesive layer by 50 to 100% expands and the reaction resin matrix to Cures a thermoset.