PRE-FIXING TWO SUBSTRATES

Abstract

A system including two pre-fixed substrates, wherein a first substrate and a second substrate. Each of the substrates has an opening in an overlap region, and an adhesive is arranged between the overlap regions, wherein the adhesive connects the two substrates together and is arranged at least partly in the openings. The adhesive is locally cured in the region of the openings. A cured sub-region of the adhesive extends from the first opening into the second opening, and a second sub-region of the adhesive is not cured.

Claims

1. A system of two pre-fixed substrates, the system comprising: a first substrate having a first opening in a first overlap region; a second substrate having a second opening in a second overlap region; and an adhesive which is arranged between the overlap regions of the first substrate and of the second substrate, wherein the adhesive both bonds the substrates together and is arranged at least partly in the openings; wherein the adhesive is locally cured in a region of the openings, wherein a cured first sub-region of the adhesive extends from the first opening into the second opening and wherein a second sub-region of the adhesive is uncured.

2. The system as claimed in claim 1, wherein the first opening and the second opening are arranged so that they overlap at least partly.

3. The system as claimed in claim 1, wherein the width of the overlap regions is from 5 mm to 40 mm.

4. The system as claimed in claim 1, wherein the maximum diameter of the openings, measured at a surface of the substrates that in each case faces away from the other substrate, is from 1 mm to 20 mm and/or is from 20 to 80% of the width of the overlap regions.

5. The system as claimed in claim 1, wherein at least one opening an undercut, and wherein the opening tapers toward a side of the substrate that faces toward the adhesive.

6. The system as claimed in claim 1, wherein the adhesive fills at least one opening completely and/or wherein the adhesive extends beyond the opening at a surface of at least one substrate that faces away from the other substrate.

7. The system as claimed in claim 1, wherein the first cured sub-region of the adhesive amounts to not more than 30% of the total adhesive.

8. The system as claimed in claim 1, wherein the substrates each have a plurality of openings, wherein an opening in the first substrate is in each case associated with an opening in the second substrate.

9. The system as claimed in claim 1, wherein the adhesive is a one-component epoxy-based or polyurethane-based adhesive.

10. The system as claimed in claim 1, wherein the substrates are formed of sheet steel and/or of aluminum sheet and/or of carbon.

11. The system as claimed in claim 1, wherein the substrates are parts of a body.

12. A method for pre-fixing two substrates, the method comprising the steps of: providing a first substrate having a first opening in a first overlap region, a second substrate having a second opening in a second overlap region, and an adhesive, arranging the adhesive between the overlap regions of the first substrate and of the second substrate so that the adhesive both bonds the substrates and is arranged at least partly in the openings; and locally curing the adhesive in a region of the openings so that a cured first sub-region of the adhesive is formed which extends from the first opening into the second opening, wherein a second sub-region of the adhesive remains uncured.

13. The method as claimed in claim 12, wherein, during the arrangement of the adhesive, the adhesive is first arranged on an overlap region of one substrate and then the other substrate is arranged with its overlap region on the adhesive, and then the two substrates are moved toward one another so that the adhesive is pressed at least partly into the openings.

14. The method as claimed in claim 12, wherein heat or radiation is applied in the region of the openings during the local curing.

15. The method as claimed in claim 12, wherein the method is carried out using a system of two pre-fixed substrates, the system comprising: the first substrate having the first opening in the first overlap region; the second substrate having the second opening in the second overlap region; and the adhesive which is arranged between the overlap regions of the first substrate and of the second substrate wherein the adhesive both bonds the substrates together and is arranged at least partly in the openings; wherein the adhesive is locally cured in the region of the openings, wherein the cured first sub-region of the adhesive extends from the first opening into the second opening and wherein the second sub-region of the adhesive is uncured.

Description

THE FIGURES SHOW

[0051] FIG. 1a to 1c an example of a system of two pre-fixed substrates;

[0052] FIG. 2 a further embodiment of an example of a system of two pre-fixed substrates;

[0053] FIG. 3 a further embodiment of a system of two pre-fixed substrates; and

[0054] FIG. 4 a perspective view of an example of a system of two pre-fixed substrates.

[0055] FIG. 1a to 1c show, by way of example and in schematic form, a first exemplary embodiment of a system 1, 1′, 1″ of two pre-fixed substrates 3, 4. FIG. 1a shows the non-pre-fixed system 1, FIG. 1b shows the pre-fixed system 1′, and FIG. 1c shows the secured system 1″.

[0056] The first substrate 3 has a first overlap region 5 in which a first opening 7 is arranged. The second substrate 4 has a second overlap region 6 in which a second opening 8 is arranged. The substrates 3, 4 are so positioned relative to one another that the respective overlap regions 5, 6 overlap completely. In this exemplary embodiment, the substrates 3, 4 are additionally so arranged relative to one another that the first opening 7 and the second opening 8 also overlap. The first opening 7 has a diameter 9 and the second opening 8 has a diameter 10, wherein the diameters 9, 10 of the openings 7, 8 are in each case measured on a side of the substrate 3, 4 that is remote from the respective other substrate 3, 4.

[0057] In the non-pre-fixed system 1, which is shown in FIG. 1a, the adhesive 2 is present in the completely uncured state.

[0058] In the pre-fixed system 1′, which is depicted in FIG. 1b, the adhesive 2 is present partly in the form of uncured adhesive 2 and partly in the form of cured adhesive 2′. In this case, the adhesive is cured in a first sub-region 12 and uncured in a second sub-region 13. This first sub-region 12 with the cured adhesive 2′ extends from the first opening 7 of the first substrate 3 into the second opening 8 of the second substrate 4. A kind of pin or stud of cured adhesive 2′ is thereby formed, which secures the substrates 3, 4 against displacement. In this exemplary embodiment, the entire cross section at the level of the openings 7, 8 is not cured. In alternative exemplary embodiments, however, the entire cross section at the level of the openings 7, 8 can also be cured, wherein the uncured second sub-region 12 then comes to lie further away from the openings 7, 8 and therefore would not be visible in such a cross-sectional view.

[0059] Finally, in the secured system 1″, shown in FIG. 1c, the adhesive 2′ is present completely in the form of cured adhesive. This state is present, for example, after treatment of the system in a painting oven.

[0060] FIG. 2 shows a further exemplary embodiment of a pre-fixed system P. In contrast to the system 1′ in FIG. 1b, in this exemplary embodiment according to FIG. 2 the openings 7 and 8 of the substrates 3, 4 are not arranged congruently or overlapping. Thus, the first sub-region 12 with the cured adhesive 2′ does not form an I-shaped anchoring, but rather a Z-shaped sub-region 12 is formed.

[0061] In addition, the openings in this example are filled not completely but only partly with adhesive 2, 2′.

[0062] FIG. 3 shows, schematically, a further exemplary embodiment, wherein the pre-fixed system 1′ has openings with an undercut. In this case, the undercut is so configured that the openings are each larger on a side remote from the adhesive 2, 2′ than on a side facing the adhesive 2, 2′, so that the openings taper toward the side facing the adhesive 2, 2′. As a result, additional anchoring of the first sub-region 12 with the cured adhesive 2′ in the respective substrates 3, 4 is obtained.

[0063] Finally, FIG. 4 shows a spatial representation of a pre-fixed system 1′. In this case, it can be seen that the first substrate 3 and the second substrate 4 overlap, wherein in each case openings are arranged in this overlap region. The overlap region additionally has a width 11. In this exemplary embodiment, the substrates 3, 4 each comprise three openings, wherein an opening of the first substrate 3 is in each case associated with an opening of the second substrate 4. In this exemplary embodiment, the openings are in each case equally spaced apart from an edge of the substrates 3, 4.

[0064] Table 1 below illustrates a test arrangement with which an effect in terms of tensile-shear strength of the system proposed here was tested. The tensile-shear strength was measured in MPa, in each case in three different substrate types (without an opening; with an opening having a diameter of 2 mm; with an opening having a diameter of 4 mm) and in each case at three different temperatures (at 23° C.; at 80° C.; at 180° C.). The adhesive used was SikaPower®-497. The substrates used were steel substrates of dimensions 100×25×1.2 mm. The substrates were oiled with Anticorit PL3802-39S, 3 g/m.sup.2. The adhesive surfaces were in each case 25×10×0.3 mm. The pulling rate was 10 mm/min. The adhesive was in each case pre-cured for 35 minutes at 175° C.

TABLE-US-00001 TABLE 1 Tensile-shear strength in MPa of different substrates at different temperatures Opening with Opening with Temperature No opening 2 mm diameter 4 mm diameter  23° C. 30.4 ± 0.4  30.3 ± 0.4  30.8 ± 0.8   80° C. 20.6 ± 0.1  21.2 ± 1.0  20.7 ± 0.9  180° C. 1.9 ± 0.2 2.3 ± 0.2 2.9 ± 0.2

[0065] It is apparent from this test that the substrates having openings in which the adhesive forms a cured pin between the openings have better high-temperature adhesion (see values at 180° C.) than the substrates without openings. At lower temperatures (see values at 23° C. and 80° C.), such an effect is less great or not pronounced.

LIST OF REFERENCE NUMERALS

[0066] 1 non-pre-fixed system [0067] 1′ pre-fixed system [0068] 1″ secured system [0069] 2 uncured adhesive [0070] 2′ cured adhesive [0071] 3 first substrate [0072] 4 second substrate [0073] 5 first overlap region [0074] 6 second overlap region [0075] 7 first opening [0076] 8 second opening [0077] 9 diameter of the first opening [0078] 10 diameter of the second opening [0079] 11 width of the overlap regions [0080] 12 first sub-region of the adhesive [0081] 13 second sub-region of the adhesive