Methods of preparing gas generant formulations

• US 5,531,845 A
• Filed: 01/10/1994
• Issued: 07/02/1996
• Est. Priority Date: 01/10/1994
• Status: Expired due to Fees

• Current Assignee: Northrop Grumman Innovation Systems, Inc. (Northrop Grumman Corporation)
• Original Assignee: Thiokol Corporation (Howmet Aerospace, Inc.)
• Inventors: Mancini, Vincent E., Harper, Michael R., Flanigan, David A.
• Primary Examiner(s): Walsh, Donald P.
• Assistant Examiner(s): CHI, ANTHONY
• Application Number:
  US08/179,728
• Time in Patent Office: 904 Days
• Field of Search: 149/109.6, 62/8, 264/3.4
• US Class Current: 149/109.6
• CPC Class Codes: B01J 2/10 in stationary drums or troughs, provided with kneading or mixing appliances
• CPC Class Codes: B01J 2/16 by suspending the powder material in a gas, e.g. in fluidised beds or as a falling curtain
• CPC Class Codes: C06B 21/0066 by granulation, e.g. flaking
• CPC Class Codes: C06B 21/0091 Elimination of undesirable or temporary components of an intermediate or finished product, e.g. making porous or low density products, purifying, stabilising, drying; Deactivating; Reclaiming; porous inert particles or chemicals compounded for these purposes C06B23/00
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

Novel methods for processing gas generant compositions to produce feed stock are disclosed. The methods of the present invention include utilizing a binding agent and other additives in a mixture of ingredients of gas generant compositions in sufficient quantities that the ingredients of the gas generating material will agglomerate to form granules as the ingredients are mixed. Processing methods, including roll coating, continuous mixing, static mixing, freeze drying, solvent extraction, emulsification, azeotropic distillation, spray drying, fluidized bed processing and particle grinding are also disclosed for use in preparing feed stock for final gas generant products. The methods of the present invention are particularly useful in processing gas generating materials having a non-azide based fuel.

Claims

1. A method for preparing gas generant feed stock, comprising the steps of:

obtaining a desired quantity of ingredients measured in predetermined ratios according to the composition of a gas generating material;

mixing together the ingredients of the gas generating material in a carrier solvent wherein at least one of the ingredients of the gas generating material becomes dissolved in the solvent;

freezing the carrier solvent;

applying sufficient quantities of heat while controlling the pressure to cause sublimation of the frozen solvent, thereby inducing the ingredients to fall out of solution;

including a binding agent in the mixture in sufficient quantities that the ingredients of the gas generating material will agglomerate to form non-curable, agglomerated granules as the ingredients are mixed; and

compacting the agglomerated granules to form a predetermined shape.

2. A method for preparing gas generant feed stock as defined in claim 1, wherein the gas generating material includes a non-azide based fuel.

3. A method for preparing gas generant feed stock as defined in claim 1, wherein the carrier solvent comprises water.

4. A method for preparing gas generant feed stock as defined in claim 1, wherein the freezing step includes the step of freezing the mixture in a refrigerant liquid.

5. A method for preparing gas generant feed stock as defined in claim 4, wherein the refrigerant liquid is selected from the group comprising nitrogen, ammonia and carbon dioxide.

6. A method for preparing gas generant feed stock as defined in claim 4, wherein the step of freezing the mixture in a refrigerant liquid is preceded by the step of supercooling the mixture under pressure in a non-contact heat exchanger.