Stable plasticizers for nitrocellulose nitroguanidine-type compositions

Claim 1

A propellant composition consisting essentially of A. a matrix component consisting essentially of one or more components selected from the group consisting of one or more of nitrocellulose, cellulose acetate, cellulose acetate butyrate, ethyl cellulose, ethyl acrylate-based polymer, and styrene acrylate type copolymer; B. an energy adjustment component consisting essentially of one or more nitramine components; and C. an effective amount of plasticizer component to accomplish gelation of said matrix component and prevent crystallization of said energy adjustment component, wherein said plasticizer component consists essentially of nitratoalkyl nitramines including at least two nitratoalkyl nitramins as follows: i. a high energy nitratoalkyl nitramine of the formula ##STR6## in which R is defined as --Alk--O--NO 2 , H, or a 1-2 carbon monovalent aliphatic group; and Alk is individually defined as a 1-2 carbon divalent aliphatic chain; said high energy alkyl nitrato-nitramine, being at least partly soluble or miscible in a second nitratoalkyl nitramine; and ii. a second nitrato alkyl nitramine having a lower energy content that said high energy nitrato alkyl nitramine component, and represented by the formula ##STR7## in which R' is individually defined as a 2-5 carbon monovalent aliphatic group of different molecular structure from the R group of formula (I) and n is defined as a positive integer not exceeding 2; D. wherein the ratio of A./B./C. components of said propellant composition being about 4-5/1-2/2-4 in parts by weight based on propellant composition in the cumulative presence of up to about 6% by weight, based on propellant composition, of one or more additives selected from the group consisting of a stabilizer, an opacifier, and a flash suppressant; and E. wherein said plasticizer component and said matrix component have solubility parameters at room temperature sufficiently consistent to maintain the gelation of said matrix component and prevent migration and crystallization of said energy adjustment component.

Claim 17

A method for improving the storage life of double based low sensitivity propellant composition comprising a matrix component, an energy adjustment component, and a nitratoalkyl nitramine plasticizer component, the improvement comprising selecting two nitratoalkyl nitramine plasticizer components of different energy in order that a solution of said plasticizer components has about the same solubility parameter as said matrix component at 70° F. wherein said method comprises: a) initially dissolving at least one high energy nitratoalkyl nitramine of the formula ##STR12## in which R is defined as --Alk--O--NO 2 , H, or a 1-2 carbon monovalent aliphatic group, and Alk is individually defined as a 1-2 carbon divalent aliphatic chain; at least in part into a second nitrato alkyl nitramine component having a lower energy content than said nitramine of formula I and represented by the formula ##STR13## in which R' is defined as a 2-5 carbon monovalent aliphatic group of different molecular structure from the R group of said high energy nitramine component, and n is defined as a positive integer not exceeding 2; (b) admixing and blending the resulting combined plasticizer component into said matrix component to obtain a dough-like mixture; (c) blending an energy adjustment component into said dough-like mixture to obtain an extrudable essentially homogeneous mass; (d) extruding said essentially homogeneous mass to obtain strands of propellant material and (e) cutting and drying said strands to obtain the desired propellant composition.

Claim 18

A method for improving the storage life of double based low sensitivity propellant composition comprising a matrix component, an energy adjustment component, and a nitratoalkyl nitramine plasticizer component, the improvement comprising selecting two nitratoalkyl nitramine plasticizer components of different energy in order that a solution of said plasticizer components has about the same solubility parameter as said matrix component at 70° F. wherein said method comprises: a) initially dissolving at least one high energy nitratoalkyl nitramine of the formula ##STR12## in which R is defined as --Alk--O--NO 2 , H, or a 1-2 carbon monovalent aliphatic group, and Alk is individually defined as a 1-2 carbon divalent aliphatic chain; at least in part into a second nitrato alkyl nitramine component having a lower energy content than said nitramine of formula I and represented by the formula ##STR13## in which R' is defined as a 2-5 carbon monovalent aliphatic group of different molecular structure from the R group of said high energy nitramine component, and n is defined as a positive integer not exceeding 2; (b) admixing and blending the resulting combined plasticizer component into said matrix component to obtain a dough-like mixture; (c) blending an energy adjustment component into said dough-like mixture to obtain an extrudable essentially homogeneous mass; (d) extruding said essentially homogeneous mass to obtain strands of propellant material and (e) cutting and drying said strands to obtain the desired propellant composition.