Low cost, low-density, ablative rubber insulation for rocket motors

Abstract

An insulation material comprising a low-density EPDM polymer, at least one flame-retardant, and an organic filler. The insulation material is used in an insulation layer of a rocket motor. The organic filler is a polymeric, organic filler such as polyvinyl chloride. A rocket motor comprising an insulation material is also disclosed. The insulation material comprises a low-density EPDM polymer, at least one flame-retardant, and a polymeric, organic filler and is applied between an inner surface of a case of the rocket motor and a propellant. A method of insulating a rocket motor is also disclosed.

1 . An insulation material for use in a rocket motor, consisting essentially of:
 a low-density ethylene propylene diene monomer polymer;   at least one flame-retardant; and   an organic filler selected from the group consisting of polyvinyl chloride, polyphenylene sulfide, melamine, and a homopolymer of vinylidene chloride.   
     
     
         2 . The insulation material of  claim 1 , wherein the at least one flame-retardant comprises at least one organic flame-retardant and at least one inorganic flame-retardant. 
     
     
         3 . The insulation material of  claim 1 , wherein the organic filler comprises polyvinyl chloride. 
     
     
         4 . The insulation material of  claim 3 , wherein the polyvinyl chloride comprise polyvinyl chloride fibers. 
     
     
         5 . The insulation material of  claim 1 , wherein the at least one flame-retardant comprises at last one silica. 
     
     
         6 . The insulation material of  claim 1 , wherein the at least one flame-retardant comprises ammonium polyphosphate. 
     
     
         7 . The insulation material of  claim 4 , wherein the polyvinyl chloride fibers have a density of 1.38 g/cc. 
     
     
         8 . An insulation material for use in a rocket motor, consisting of:
 a low-density ethylene propylene diene monomer polymer;   at least one flame retardant;   an organic filler selected from the group consisting of polyvinyl chloride, melamine, and a homopolymer of vinylidene chloride;   sulfur; and   at least one additive selected from the group consisting of at least one antioxidant, at least one cure accelerator, at least one cure activator, at least one tackifier, and at least one plasticizer.   
     
     
         9 . The insulation material of  claim 8 , further comprising carbon black. 
     
     
         10 . The insulation material of  claim 8 , wherein the insulation material comprises 1.0 parts by weight of carbon black. 
     
     
         11 . An insulation material for use in a rocket motor, comprising:
 a low-density ethylene propylene diene monomer polymer;   at least one flame retardant;   sulfur;   polyvinyl chloride fibers having a density of 1.38 g/cc; and   at least one additive selected from the group consisting of at least one antioxidant, at least one cure accelerator, at least one cure activator, at least one tackifier, and at least one plasticizer.   
     
     
         12 . The insulation material of  claim 11 , wherein the polyvinyl chloride fibers are dispersed randomly in the insulation material. 
     
     
         13 . The insulation material of  claim 11 , wherein the insulation material consists of a low-density ethylene propylene diene monomer polymer, at least one flame retardant, sulfur, polyvinyl chloride fibers having a density of 1.38 g/cc, and at least one additive selected from the group consisting of at least one antioxidant, at least one cure accelerator, at least one cure activator, at least one tackifier, and at least one plasticizer. 
     
     
         14 . An insulation material for use in a rocket motor, comprising:
 a low-density ethylene propylene diene monomer polymer;   at least one flame-retardant; and   polyvinyl chloride fibers having a density of 1.38 g/cc.   
     
     
         15 . The insulation material of  claim 14 , wherein the insulation material consists of a low-density ethylene propylene diene monomer polymer, at least one flame-retardant, and polyvinyl chloride fibers having a density of 1.38 g/cc