One-component structural adhesive containing isocyanate-terminated prepolymer

1. A method for bonding coated or painted parts made of fiber-reinforced plastics; said method comprising the steps of applying a one-component adhesive consisting essentially of i) 45 to 90 wt %, based on the weight of the adhesive, of an isocyanate-terminated prepolymer consisting essentially of polymerized residues of (a) 40 to 95 wt %, based on the weight of the prepolymer, of a polytetramethylene ether glycol; and (b) 5 to 60 wt % based on the weight of the prepolymer, of an aliphatic diisocyanate, wherein the prepolymer contains 1.5 to 5 weight percent isocyanate groups, ii) a bismuth, tin or amine catalyst, iii) a filler that includes carbon black, kaolin and fumed silica and optionally (iv) a plasticizer to said parts and curing the adhesive.

2. The method of claim 1 in which the aliphatic diisocyanate is hexamethylene diisocyanate.

3. The method of claim 2 in which the polytetramethylene ether glycol has an Mn from 500 to 3000.

4. The method of claim 3 wherein the isocyanate-terminated prepolymer contains from 55 to 90 wt % of polymerized residues of the polytetramethylene ether glycol; and 10 to 45 wt % of polymerized residues of the aliphatic diisocyanate.

5. The method of claim 4 in which the fiber reinforced plastic is an epoxy composite.

6. The method of claim 4 in which adhesive contains from 7 to 40 wt % carbon black based on the weight of the adhesive.

7. The method of claim 6 wherein the adhesive further contains 9 to 40% kaolin based on the weight of the adhesive.

8. The method of claim 7 wherein the catalyst includes a bismuth catalyst.

9. The method of claim 4 wherein the catalyst includes a bismuth catalyst.

10. The method of claim 1 wherein the plasticizer is absent.