INSTANT PRE-FIXATION OF ADHESIVE BONDED INSERT PARTS WHICH IS PREFERABLY MADE OF PLASTIC WITH THE HELP OF CHEMICAL SCREWS

Abstract

An assembly comprising a substrate 1, a substrate 2 and heat curable adhesive, which is positioned between the substrates 1 and 2, wherein the heat curable adhesive is cured only in a portion of less than 50% of the entire surface covered by the heat curable adhesive. In this manner, the cured parts of the adhesive serve as chemical screws which sufficiently fix the substrates together during further processing steps, but do not involve complete curing of the adhesive.

Claims

1. An assembly comprising a substrate 1, a substrate 2 and heat curable adhesive, which is positioned between the substrates 1 and 2, wherein the heat curable adhesive is cured only in a portion of less than 50% of the entire surface covered by the heat curable adhesive.

2. The assembly according to claim 1, wherein the substrate 1 is a profile and the substrate 2 is an extruded or molded carrier.

3. The assembly according to claim 1, further comprising a substrate 3 on the side of the substrate 2, which is opposite the substrate 1, and a heat curable adhesive, which is positioned between the substrate 2 and the substrate 3, wherein the heat curable adhesive, which is positioned between the substrate 2 and the substrate 3 is cured only in a portion of less than 50% of the entire surface covered by the heat curable adhesive.

4. A process for the preparation of an assembly according to claim 1 comprising the steps of (i) placing at least one heat curable adhesive bead on the substrate 1, (ii) placing the substrate 2 on the heat curable adhesive bead such that the substrate 1 and 2 are on opposite sides of the bead, and (iii) applying heat to the heat curable adhesive only in a portion of less than 50% of the entire surface covered by the bead of the heat curable adhesive.

5. A process for the preparation of an assembly according to claim 1 comprising the steps of (i) placing the substrate 1 on the substrate 2 in a manner, that there is a hollow space between the substrates 1 and 2, (ii) injecting a flowable heat curable adhesive into the hollow space between the substrates 1 and 2, (iii) applying heat to the flowable heat curable adhesive only in a portion of less than 50% of the entire surface covered by the flowable adhesive to cure the adhesive.

6. A process for the preparation of an assembly according to claim 1 comprising the steps of (i) placing the substrate 1 on the substrate 2, wherein the substrate 2 has a layer of heat curable adhesive one at least on side of the substrate and wherein the substrate 2 is placed on the substrate 1 in a manner so that there is direct contact between the substrate 1 and the curable adhesive on the substrate 2, (ii) applying heat to the curable adhesive only in a portion of less than 50% of the entire surface covered by the heat curable adhesive to cure the adhesive.

7. A process for the preparation of an assembly according to claim 1, comprising the steps of (iv) placing a expandable heat curable adhesive on the substrate 2, wherein the expandable curable adhesive is self-adherent at 25 C., (v) placing the substrate 1 over the expandable heat curable adhesive on the substrate 2 such that the substrate 1 contacts the expandable heat curable adhesive, or that there is a gap between the expandable heat curable adhesive and the substrate 2, which is filled with the heat curable adhesive upon expansion, (vi) applying heat to the expandable heat curable adhesive only in a portion of less than 50% of the entire surface covered by the heat curable adhesive to cure the adhesive.

8. The process according to claim 4, wherein heat is applied to the heat curable adhesive only in a portion of less than 30% of the entire surface covered by the bead.

9. The process according to claim 4, wherein heat is applied to more than one independent areas of the entire surface covered by the bead.

10. The process according to claim 4, wherein the heat is applied by means of induction, infrared or microwaves.

11. The process according to claim 4, which further comprises the steps of (iv) placing at least one heat curable adhesive bead on the side of substrate 2, which is opposite to the side facing the substrate 1, (v) placing a further substrate 3 on the heat curable adhesive bead placed in step (iv) such that the substrates 2 and 3 are on opposite sides of the bead, wherein the heat in step (iii) is applied to each of the heat curable adhesive beads only in a portion of less than 50% of the entire surface of the respective beads to cure the adhesive.

12. The process according to claim 4, wherein the substrate 1 is a metal substrate.

13. The process according to claim 4, wherein the substrate 1 has the shape of a profile.

14. The process according to claim 4, wherein the substrate 2 is an extruded or molded carrier.

15. The process according to claim 4, wherein the heat curable adhesive is an epoxy or polyurethane based adhesive.

16. A process comprising: manufacturing a vehicle by using the process of claim 4.

17. The process of claim 16 further comprising subjecting the substrate 1 and substrate 2 to an electrocoating step comprising submerging the assembly in an e-coat fluid and inserting the assembly into an e-coat oven, wherein the adhesive is fully cured said oven.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0129] FIG. 1 A shows an assembly according to the present application consisting of an U-shaped substrate 1 a rectangular substrate 2 (grey) and two heat-curable adhesive beads positioned between the two substrates. Item B of this Figure shows the same assembly with the adhesive in cured form.

[0130] FIG. 2 A shows a second embodiment of the present application with a U-shaped substrate 1, a rectangular substrate 2 (in grey) and a planar substrate 3, wherein adhesive beads have been positioned between the substrate 2 and the U-shaped substrate 1 as well as between a substrate 2 and the linear substrate 3. In item B, the respective adhesives have been cured.

[0131] FIG. 3 A shows an extended adhesive bead (light grey) between two substrates which is subjected to heat curing only at two small portions thereof (arrows). The heat cures the adhesive only in the portions indicated as dark grey in item B of FIG. 3.

[0132] In the following, the present application will be explained by way of examples which, however, are intended for illustrative purposes only. Hence, the present application is not limited to the embodiments exemplified here in an after.

EXAMPLES

Example 1

[0133] To test the inventive concept, different adhesives were pre-cured on aluminium by induction with different parameters. The obtained products were subjected to a comparison of the tensile shear strength and the reactivity. In addition, it was investigated whether the pre-curing and the subsequent full curing has an impact on the stability of the adhesive bond.

[0134] The following materials were used as adhesives: [0135] a) SikaPower-490B3, Ch: 0011082913/1445 (Sika Italy, Cerano) [0136] b) Betamate 1480 (Dow) [0137] c) Terokal 8026 (Henkel)

[0138] The further test parameters were as follows: [0139] substrate: AA6016 TiZr [0140] cleaning: none, as supplied [0141] application: RT [0142] dimension of adhesive film: 25100.3 mm [0143] traversing speed: 10 mm/min [0144] start temperature induction: 50 C. [0145] pre-curing: Induction apparatus EW2

[0146] The specific parameters of the induction test are provided in the following table:

TABLE-US-00001 TABLE 1 Parameter- Parameter- Programm Temperature heating phase holding phase 170-1 30 sec for 170 C. frequency 1: 13 frequency 2: 17.5 60 sec for 170 C. PWM: 38 VWR: 95 USS: 99 VRP: 95 VIR: 10 180-1 30 sec for 180 C. frequency 1: 13 frequency 2: 17.5 60 sec for 180 C. PWM: 41 VWR: 95 USS: 99 VRP: 95 VIR: 10 180-2 30 sec for 180 C. frequency 1: 13 frequency 2: 17.5 60 sec for 180 C. PWM: 41 VWR: 95 USS: 99 VRP: 95 VIR: 10 190-1 30 sec for 190 C. frequency 1: 13 frequency 2: 17.5 60 sec for 190 C. PWM: 44 VWR: 95 USS: 99 VRP: 95 VIR: 10 190-2 30 sec for 190 C. frequency 1: 13 frequency 2: 17.5 60 sec for 190 C. PWM: 44 VWR: 95 USS: 99 VRP: 95 VIR: 10 PWM: pulse width modulation, USS: Switchover treshhold, VWR: pre-control modulation, VPR: Multiplier proportional modulator value, VIR: Multiplier integral modulator value

[0147] The respective temperatures were measured on the bottom side of each sample.

[0148] After the initial curing the respective samples provided the tensile shear strength values as indicated in table 2:

TABLE-US-00002 TABLE 2 Sika-Power- Terokal Betamate program Time/temperature 490B3 8026 1480 170-1 30 sec for 170 C. 2.6 MPa 2.0 MPa 5.3 MPa 60 sec for 170 C. 180-1 30 sec for 180 C. 8.0 MPa 5.3 MPa 15.3 MPa 60 sec for 180 C. 180-2 30 sec for 180 C. 3.5 MPa 5.2 MPa 9.7 MPa 30 sec for 180 C. 190-1 30 sec for 190 C. 16.0 MPa 7.0 MPa 14.8 MPa 60 sec for 190 C. 190-2 30 sec for 190 C. 9.0 MPa 6.8 MPa 12.6 MPa 30 sec for 190 C.

[0149] The results of table 2 show that a temperature of 170 C. provides a sufficient handling strength (>2 MPa) with the tested adhesives to provide a process secure inductive pre-curing on aluminium. At higher pre-curing temperatures (180 C.) and holding times of at least 60 sec all adhesives provide even higher strength. In contrast to Terokal 8026 both Sika-Power-490B3 and Betamate 1480 show a better appearance of fracture.

[0150] Pursuant to the initial curing the samples were cured for 25 min at 175 C. which are typical conditions in the paint oven of the Automotive body process. The tensile shear strength values obtained after full cure are indicated in the following table 3:

TABLE-US-00003 TABLE 3 Sika-Power- Betamate program Time/temperature Substrate 490B3 1480 No pre-curing AA 6016 TiZr 19.5 MPa 20.5 MPa 1.2 mm 170-1 30 sec for 180 C. AA 6016 TiZr 18.0 MPa 20.5 MPa 60 sec for 180 C. 1.2 mm 180-2 30 sec for 190 C. AA 6016 TiZr 19.5 MPa 20.5 MPa 30 sec for 190 C. 1.2 mm 190-2 30 sec for 190 C. AA 6016 TiZr 19.5 MPa 20.5 MPa 30 sec for 190 C. 1.2 mm

[0151] The results show that for a pre-curing at 180 C. of more, no difference could be detected between a sample which was inductively pre-cured and a sample which was not subjected to a pre-curing.