Structured endothermic fire-retardant agents

1. A fire-retardant composition comprising:

a microcapsule comprising a first reagent encapsulated with a first encapsulating material and a second reagent encapsulated with a second encapsulating material;

wherein:

the first reagent is isolated from the second reagent; and

the first reagent and the second reagent are configured to react with each other endothermically;

wherein the first encapsulating material comprises a thermally-sensitive material, and

wherein the thermally-sensitive material comprises an ethylene-vinyl alcohol co-polymer, neoprene, a chlorinated polyethylene, a chlorosulfonated polyethylene, a polyvinylidene chloride, a polyvinylidene chloride-methyl acrylate co-polymer, or a combination of any two or more thereof.

2. The fire-retardant composition of claim 1 , wherein the microcapsule comprises a core comprising the first reagent and a shell comprising the second reagent.

3. The fire-retardant composition of claim 1 , wherein the second encapsulating material comprises a thermally-sensitive material.

4. The fire-retardant composition of claim 3 , wherein the thermally-sensitive material comprises an ethylene-vinyl alcohol co-polymer, neoprene, a chlorinated polyethylene, a chlorosulfonated polyethylene, a polyvinylidene chloride, a polyvinylidene chloride-methyl acrylate co-polymer, or a combination of any two or more thereof.

5. The fire-retardant composition of claim 1 , wherein the first encapsulating material and the second encapsulating material are configured to allow the first reagent to contact the second reagent upon heating.

6. The fire-retardant composition of claim 1 , wherein the first reagent comprises urea, dimethyl urea, diethylurea, 1,3-dimethyl-1,3-diphenyl urea, 1,1-dimethyl urea, 1,3-dimethyl urea, 1,3-diphenyl urea, 1,3-bis(4-methylphenyl)urea, 1,3-bis(4-methoxyphenyl)urea, 1,3-bis(4-ethoxyphenyl)urea, or a combination of any two or more thereof.

7. The fire-retardant composition of claim 1 , wherein the second reagent comprises ammonium chloride, ammonium hypophosphite, ammonium nitrate, ammonium sulfate, ammonium carbonate, ammonium bromide, ammonium iodide, or a combination of any two or more thereof.

8. A fire-retardant composition comprising:

a polymer matrix; and

a plurality of microcapsules dispersed in the polymer matrix, wherein each of the plurality of the microcapsules comprises a first reagent encapsulated with a first encapsulating material and a second reagent encapsulated with a second encapsulating material;

wherein:

the first reagent is isolated from the second reagent; and

the first reagent and the second reagent are configured to react with each other endothermically;

wherein the first encapsulating material comprises a thermally-sensitive material, and

wherein the thermally-sensitive material comprises an ethylene-vinyl alcohol co-polymer, neoprene, a chlorinated polyethylene, a chlorosulfonated polyethylene, a polyvinylidene chloride, a polyvinylidene chloride-methyl acrylate co-polymer, or a combination of any two or more thereof.

9. The fire-retardant composition of claim 8 , wherein the polymer matrix comprises a thermoset polymer, a thermoplastic polymer, or a combination of any two or more thereof.

10. The fire-retardant composition of claim 8 , wherein the polymer matrix comprises polyethylene, polypropylene, poly(butylene terephthalate), poly(ethylene terephthalate), acrylonitrile-butadiene-styrene, high impact polystyrene, a rubber latex, silicone, nylon, or a combination of any two or more thereof.

11. The fire-retardant composition of claim 8 , wherein the polymer matrix comprises high impact polystyrene.

12. The fire-retardant composition of claim 8 , wherein the polymer matrix is present in the composition at a concentration of about 5 wt % to about 45 wt %.

13. The fire-retardant composition of claim 8 , wherein each of the plurality of microcapsules have an average particle diameter of about 2 μm and about 10 μm.

14. The fire-retardant composition of claim 8 , further comprising a filler, an additive, or both a filler and an additive.

15. A process of making a fire-retardant composition, the process comprising:

coating a first reagent with a first encapsulant to form a first encapsulated reagent;

coating a second reagent with a second encapsulant to form a second encapsulated reagent; and

incorporating the first encapsulated reagent and the second encapsulated reagent into a microcapsule;

wherein the first encapsulating material comprises a thermally-sensitive material, wherein the thermally-sensitive material comprises an ethylene-vinyl alcohol co-polymer, neoprene, a chlorinated polyethylene, a chlorosulfonated polyethylene, a polyvinylidene chloride, a polyvinylidene chloride-methyl acrylate co-polymer, or a combination of any two or more thereof.

16. The process of claim 15 , further comprising dispersing a plurality of microcapsules in a polymer matrix.

17. The process of claim 15 , wherein the fire-retardant composition is in the form of an extruded or molded article.

18. The fire-retardant composition of claim 1 , wherein the microcapsule has an average particle diameter of about 1 μm and about 500 μm.

19. The fire-retardant composition of claim 1 , wherein the microcapsule has an average particle diameter of about 2 μm and about 10 μm.

20. The fire-retardant composition of claim 8 , further comprising an antioxidant, a UV absorber, a heat stabilizer, a light stabilizer, or a combination of any two or more thereof.