Fire retardant insulation

A flame retardant, thermal insulation material comprising:

• (a) dry, shredded, cellulosic material;
• and
• (b) a substantially dry, powdered, flame retardant composition which includes a plurality of compounds which are phosphorous containing compounds selected from the group consisting of phosphates and phosphites which decompose at a plurality of different temperatures spaced within a temperature range of substantially 120.degree. Celsius to 250.degree. C. to evolve phosphoric acid and other agents which retard the exothermic oxidation of said cellulosic material and decomposition products thereof, said composition being distributed on the surface of said shredded material.

A flame retardant for a dry, shredded, cellulosic, thermal insulation material, said retardant comprising a substantially dry, powdered, phosphorous-containing, flame retardant composition which decomposes to evolve phosphoric acid substantially at the temperatures at which the insulation material has sufficient thermal feedback to sustain its rapid oxidation wherein said composition comprises calcium phosphate or dry powered triple super phosphate or both and at least one other flame retardant compound which decomposes at a temperature different from said phosphate.

A flame retardant for a dry, shredded, cellulosic, thermal insulation material, said retardant comprising a substantially dry, powdered, phosphorous-containing, flame retardant composition which decomposes to evolve phosphoric acid substantially at the temperature at which the insulation material has sufficient thermal feedback to sustain its rapid oxidation wherein said phosphorous containing composition comprises diammonium phosphate and calcium phosphate and wherein said retardant further comprises dry powdered urea.

A flame retardant for a dry, shredded, cellulosic, thermal insulation material, said retardant comprising a substantially dry, powdered, phosphorous-containing, flame retardant composition which decomposes to evolve phosphoric acid substantially at the temperature at which the insulation material has sufficient thermal feedback to sustain its rapid oxidation wherein said retardant comprises substantially 2 parts urea, 1 part diammonium phosphate, 3 parts triple super phosphate and a neutralizing agent.

A flame retardant for a dry, shredded, cellulosic, thermal insulation material, said retardant comprising a substantially dry, powdered, phosphorous-containing, flame retardant composition which decomposes to evolve phosphoric acid substantially at the temperature at which the insulation material has sufficient thermal feedback to sustain its rapid oxidation wherein said retardant comprises substantially 2 parts urea, 4 parts triple superphosphate and a neutralizing agent.

A flame retardant for a dry, shredded, cellulosic thermal insulation material, said retardant comprising a substantially dry, powdered, phosphorous-containing, flame retardant composition which decomposes to evolve phosphoric acid substantially at the temperature at which the insulation material has sufficient thermal feedback to sustain its rapid oxidation wherein said retardant includes urea, calcium carbonate and triple super phosphate and wherein the ratio of urea to the total phosphate compounds is essentially 1:2 and the ratio of calcium carbonate to triple super phosphate is essentially 1:8.