Intumescent fire sealing composition
Assignee3M Innovative Properties Company
InventorsMark R. Buckingham, Walton W. Welna
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Abstract
Described is a flexible, solid fire sealant produced by high shear mixing in a substantially volatile-free state and capable of being molded or extruded into a variety of shapes and used as firestops for windows, doors, dampers, shutters, and through-penetrations, the sealant containing water-insoluble intumescent mineral granules, a polymeric, halogen-free binder, and a flame retardant, wherein the sealant has a softness value from about 0.01 to about 3.75 mm and exhibits high expansion values and chars upon exposure to heat.
Claims1
A method of preparing a flexible solid intumescent fire barrier material, comprising the steps of:
- (a) providing a halogen-free organic binder in the form of a latex binder;
- (b) drying the latex binder to remove any volatiles;
- (c) combining, in a substantially volatile free state, a mixture consisting essentially of the latex binder, water-insoluble intumescent mineral granules, and phosphorus containing flame retardant;
- and
- (d) mixing the mixture at high shear conditions using a twin screw extruder;
- wherein the resulting fire barrier material has a softness value from about 0.49 to about 1.45 mm and an expansion ratio from about 6.9 to about 8.8.
Dependencies are inferred from the claim text.