Insulative compositions, article incorporating the same and methods of forming the same

Abstract

Precursors, insulative compositions, an article including the insulative compositions and a method for making the insulative compositions are disclosed. The insulative compositions are formed from a precursor composition that includes a nitride butadiene rubber, a nanoclay and a cure package including a sulfur-based curing agent. The insulative compositions may have a substantially reduced weight and compressive modulus in comparison to conventional insulative rubbers. Thus, the insulative compositions may provide improved ballistic properties in addition to reduced density and thickness. Precursor compositions for forming the insulative composition may have good flow characteristics. The insulative compositions may be used in a variety of applications, such as personnel body armor, ground vehicle armor and aircraft armor systems.

1 . An insulative composition, comprising, before curing:
 at least one nitrile butadiene rubber comprising between about 60% by weight and about 70% by weight of a total weight of the insulative composition;   a nanoclay; and   a cure package comprising a sulfur-based curing agent.   
     
     
         2 . The insulative composition of  claim 1 , wherein the at least one nitrile butadiene rubber comprises about 62.25% by weight of a total weight of the insulative composition. 
     
     
         3 . The insulative composition of  claim 1 , wherein the nanoclay comprises a montmorillonite clay. 
     
     
         4 . The insulative composition of  claim 1 , wherein the cure package further comprises at least one of tetramethyl thiuram disulfide and benzothiazyl disulfide. 
     
     
         5 . The insulative composition of  claim 4 , wherein the sulfur-based curing agent comprises about 1.31% by weight of the total weight of the insulative composition, the tetramethyl thiuram disulfide comprises about 0.33% by weight of the total weight of the insulative composition, and the benzothiazyl disulfide comprises about 0.65% by weight of the total weight of the insulative composition. 
     
     
         6 . The insulative composition of  claim 1 , wherein the nanoclay comprises between about 8% by weight and about 12% by weight of the total weight of the insulative composition. 
     
     
         7 . The insulative composition of  claim 1 , further comprising at least one of an antioxidant, a tackifier, a processing aid, a plasticizer, and an activator. 
     
     
         8 . The insulative composition of  claim 1 , further comprising at least one of an amine antioxidant, a phenolic resin, stearic acid, dioctyl phthalate, and zinc oxide. 
     
     
         9 . An insulative composition, comprising, before curing:
 a polymer comprising at least one nitrile butadiene rubber;   a nanoclay; and   a cure package comprising a sulfur-based curing agent and at least one of tetramethyl thiuram disulfide and benzothiazyl disulfide,   wherein the insulative composition is an isotropic material.   
     
     
         10 . The insulative composition of  claim 9 , wherein the cure package consists of the sulfur-based curing agent, the tetramethyl thiuram disulfide, and the benzothiazyl disulfide. 
     
     
         11 . The insulative composition of  claim 10 , wherein the sulfur-based curing agent consists of about 1.31% by weight of a total weight of the insulative composition, the tetramethyl thiuram disulfide comprises about 0.33% by weight of the total weight of the insulative composition, and the benzothiazyl disulfide comprises about 0.65% by weight of the total weight of the insulative composition. 
     
     
         12 . The insulative composition of  claim 9 , wherein the at least one nitrile butadiene rubber comprises from about 26% by weight to about 35% by weight of a total weight of the insulative composition. 
     
     
         13 . The insulative composition of  claim 9 , wherein the nanoclay is homogeneously dispersed within the polymer. 
     
     
         14 . The insulative composition of  claim 9 , wherein the nanoclay comprises magnesium aluminum silicate platelets modified with a quaternary ammonium salt. 
     
     
         15 . The insulative composition of  claim 9 , further comprising at least one of an amine antioxidant, a phenolic resin, stearic acid, dioctyl phthalate, and zinc oxide. 
     
     
         16 . A precursor composition comprising:
 a polymer comprising at least one nitrile butadiene rubber;   a nanoclay; and   a cure package comprising a sulfur-based curing agent, wherein the precursor composition has a flowable consistency.   
     
     
         17 . The precursor composition of  claim 16 , wherein the precursor composition has a Mooney viscosity of between about 5 and about 30. 
     
     
         18 . An article of manufacture, comprising:
 a sheet of fibrous material; and   a precursor composition disposed on the sheet of fibrous material, comprising:
 at least one nitrile butadiene rubber; 
 a nanoclay; and 
 a cure package comprising a sulfur-based curing agent and at least one of tetramethyl thiuram disulfide and benzothiazyl disulfide, 
   wherein the precursor composition is fiber-free.   
     
     
         19 . A method of forming a precursor of an insulative composition, comprising:
 exfoliating a nanoclay with a polymer comprising at least one nitrile butadiene rubber to form a master batch comprising a homogeneous mixture of the nanoclay and the polymer;   mixing a portion of the master batch with a cure agent to form a mixture; and   combining a remaining portion of the master batch with the mixture to form a precursor composition having a flowable consistency.   
     
     
         20 . The method of  claim 19 , wherein exfoliating a nanoclay with a polymer comprising at least one nitrile butadiene rubber to form a master batch comprising a homogeneous mixture of the nanoclay and the polymer comprises mixing the at least one nitrile butadiene rubber with the nanoclay for between about 5 minutes and about 25 minutes to form the master batch. 
     
     
         21 . The method of  claim 19 , wherein exfoliating a nanoclay with a polymer comprising at least one nitrile butadiene rubber to form a master batch comprising a homogeneous mixture of the nanoclay and the polymer further comprises mixing an amine antioxidant and a phenolic resin with the master batch. 
     
     
         22 . The method of  claim 19 , wherein mixing a portion of the master batch with a cure agent to form a mixture comprises mixing about one-half of a total volume of the master batch with the cure agent to form the mixture. 
     
     
         23 . The method of  claim 19 , wherein mixing a portion of the master batch with a cure agent to form a mixture comprises mixing the master batch with laccofine sulfur and at least one of tetramethyl thiuram disulfide and benzothiazyl disulfide to form the mixture. 
     
     
         24 . The method of  claim 19 , further comprising adding at least one of a tackifier, an activator and a plasticizer to the master batch before mixing the portion of the master batch with the cure agent. 
     
     
         25 . The method of  claim 19 , wherein combining a remaining portion of the master batch with the mixture to form a precursor composition having a flowable consistency comprises combining the remaining portion of the master batch with the mixture to form a precursor having a Mooney viscosity of less than about 30. 
     
     
         26 . The insulative composition of  claim 1 , wherein the insulative composition is an isotropic material.