Mixture curable to provide an intumescent coating material

1. A mixture curable to provide an intumescent coating material, wherein the mixture comprises a silicone polymer, a cross-linker, a diluent and an intumescent ingredient, wherein the mixture comprises at least 50% by weight of the intumescent ingredient and wherein the diluent comprises a plasticiser.

2. A mixture according to claim 1 , wherein the mixture comprises 50 to 68% by weight of the intumescent ingredient.

3. A mixture according to claim 1 , wherein the intumescent ingredient comprises a phosphorus containing compound, a gas source, and a carbon source.

4. A mixture according to claim 1 , wherein the intumescent ingredient comprises an infrared blocker.

5. A mixture according to claim 1 , wherein the mixture comprises 1 to 35% by weight of the diluent.

6. A mixture according to claim 1 , wherein the mixture comprises 2 to 15% by weight of the diluent.

7. A mixture according to claim 1 , wherein the diluent comprises an organic solvent.

8. A mixture according to claim 7 , wherein the diluent comprises xylene, toluene, alkanes, alkenes, or aromatics.

9. A mixture according to claim 1 , wherein the plasticiser comprises trimethyl terminated polydimethyl siloxane with viscosity range of 0.65 cSt to 1000 cSt, a mixture of aliphatic and aromatic hydrocarbons with 7-30 carbon atoms, mellitates, phthalates, sebacates or adipates.

10. A mixture according to claim 1 , wherein the diluent comprises functionalised polydialkyl siloxane, polydialkyl siloxane polyether copolymer chains with hydroxy, alkoxy, carbinol, epoxy, vinyl, SiH, acrylate, isocyanate or amino functionalities.

11. A mixture according to claim 1 , wherein the mixture comprises 0.25 to 6% by weight of an endothermic fire retardant.

12. A mixture according to claim 1 , wherein the mixture comprises 0.25 to 8% by weight reinforcing fibres.

13. A mixture according to claim 1 , wherein the mixture comprises 0.25 to 15% by weight filler.

14. A mixture according to claim 1 , wherein the mixture comprises 14 to 31% by weight of the silicone polymer and 1 to 10% by weight of the cross-linker.

15. A mixture according to claim 1 , wherein the mixture comprises less than 5% by weight expandable graphite.

16. A mixture according to claim 1 , wherein the mixture is substantially free of expandable graphite.

17. An intumescent coating material, wherein the intumescent coating material is the cured reaction product of a mixture comprising a silicone polymer, a cross-linker, a diluent and an intumescent ingredient, wherein the mixture comprises at least 50% by weight of the intumescent ingredient, and wherein the diluent comprises a plasticiser.

18. A method of protecting a substrate, the method comprising:

coating the substrate with a mixture curable to provide an intumescent coating material, wherein the mixture comprises a silicone polymer, a cross-linker, a diluent and an intumescent ingredient, wherein the mixture comprises at least 50% by weight of the intumescent ingredient, and wherein the diluent comprises a plasticiser; and

allowing the mixture to cure.