Primerless polyurethane adhesive compositions

1. A polyurethane adhesive composition comprising:

(a) one or more urethane prepolymers having isocyanate moieties;

(b) a catalytic amount of one or more catalysts;

(c) one or more fillers;

(d) one or more silane adhesion promoters; and

(e) one or more monofunctional polyalkylene glycols.

2. The polyurethane adhesive composition according to claim 1 , wherein the one or more urethane prepolymers are derived from a polyol containing alkylene oxide units of ethylene oxide, propylene oxide or mixtures thereof.

3. The polyurethane adhesive composition according to claim 1 , wherein the one or more urethane prepolymers are derived from an aromatic isocyanate compound.

4. The polyurethane adhesive composition according to claim 1 , wherein the one or more catalysts are selected from compounds containing one or more tertiary amine groups.

5. The polyurethane adhesive composition according to claim 4 , wherein the one or more catalysts are selected from dimorpholino dialkyl ethers.

6. The polyurethane adhesive composition according to claim 1 , wherein the one or more fillers are one or more forms of carbon black and one or more calcium carbonates.

7. The polyurethane adhesive composition according to claim 1 , wherein the polyurethane adhesive composition does not contain clay.

8. The polyurethane adhesive composition according to claim 1 , wherein the one or more silane adhesion promoters are selected from alkoxysilanes.

9. The polyurethane adhesive composition according to claim 1 , wherein the one or more polyalkylene glycols are a C 1 to C 12 monofunctional alcohol initiated polyalkylene oxide chain wherein the polyalkylene oxide chain comprises units of ethyleneoxy propyloxy, butyleneoxy or a mixture thereof.

10. The polyurethane adhesive composition according to claim 1 , wherein the one or more polyalkylene glycols have a number average molecular weight of 200 to 2,000.

11. The polyurethane adhesive composition according to claim 1 , comprising:

(a) 20 to 85 wt. % of the one or more urethane prepolymers having isocyanate moieties, based on the weight of the polyurethane adhesive composition;

(b) 0.3 to 3.5 wt. % of the one or more catalysts, based on the weight of the polyurethane adhesive composition;

(c) 15 to 50 wt. % of the one or more fillers, based on the weight of the polyurethane adhesive composition;

(d) 0.1 to 5 wt. % of the one or more silane adhesion promoters, based on the weight of the polyurethane adhesive composition; and

(e) 0.1 to 5 wt. % of the one or more polyalkylene glycols, based on the weight of the polyurethane adhesive composition.

12. The polyurethane adhesive composition according to claim 8 , comprising:

(a) 30 to 65 wt. % of the one or more urethane prepolymers having isocyanate moieties, based on the weight of the polyurethane adhesive composition;

(b) 0.1 to 2.6 wt. % of the one or more catalysts, based on the weight of the polyurethane adhesive composition;

(c) 15 to 23 wt. % of the one or more forms of carbon black, based on the weight of the polyurethane adhesive composition;

(d) 8 to 20 wt. % of the one or more calcium carbonates and 0.7 to 3 wt. % of the one or more silane adhesion promoters, based on the weight of the polyurethane adhesive composition; and

(e) 0.4 to 2 wt. % of the one or more polyalkylene glycols, based on the weight of the polyurethane adhesive composition.

13. A method comprising

(a) applying a polyurethane adhesive composition to at least a portion of a first substrate, wherein the polyurethane adhesive composition comprises:

(i) one or more urethane prepolymers having isocyanate moieties;

(ii) a catalytic amount of one or more catalysts;

(iii) one or more fillers;

(iv) one or more silane adhesion promoters; and

(v) one or more monofunctional polyalkylene glycols,

(b) contacting a second substrate with the first substrate; and

(c) curing the polyurethane adhesive composition to form an adhesive bond between the first substrate and the second substrate.

14. The method according to claim 13 , wherein the first substrate is glass or coated plastic.