Spiral grain solid propellant fabrication process

• US 4,013,743 A
• Filed: 02/12/1973
• Issued: 03/22/1977
• Est. Priority Date: 02/12/1973
• Status: Expired due to Term

• Current Assignee: Rockwell International Corporation
• Original Assignee: Rockwell International Corporation
• Inventors: Blasche, Thomas L. Jr., Corley, Boyce M., Kobbeman, Donald D.
• Primary Examiner(s): Sebastian, Leland A.
• Application Number:
  US05/331,404
• Time in Patent Office: 1,499 Days
• Field of Search: 86/1 R, 102/102, 102/103, 149/76, 264/3 R
• US Class Current: 264/3.1
• CPC Class Codes: C06B 21/0058 by casting a curable composition, e.g. of the plastisol type
• CPC Class Codes: C06B 45/00 Compositions or products which are defined by structure or arrangement of component of product explosive charges of particular form or shape F42B1/00, F42B3/00
• CPC Class Codes: F02K 9/14 made from sheet-like materials, e.g. of carpet-roll type, of layered structure
• CPC Class Codes: F05D 2250/15 spiral
• CPC Class Codes: F05D 2250/25 helical

Abstract

A solid propellant motor is fabricated by spreading a propellant onto an uncured reinforced fabric tape to a uniform thickness and then partially curing the mass to a semi-rigid state. The semi-rigid blanket is then rolled with an air gap between the spirally wound layers. The final configuration of the motor is subsequently fully cured.

Claims

1. A method of fabricating a spirally wound, solid propellant motor grain with a support structure therein, the improvement comprising the steps of:

spreading a layer of uncured solid propellant onto both sides of a support structure, said solid propellant being an ammonium perchlorate oxidized composition containing a binder system that cures at a relatively high temperature, said support structure being a flexible, uncured, reinforced fabric tape with a thermosetting resin binder thereon that cures at a relatively high temperature,

partially curing said uncured solid propellant applied to both sides of said uncured flexible support structure to a gelled state,

forming said partially cured solid propellant and support structure into a layered, longitudinally-extending, spirally-wrapped solid propellant motor configuration, said propellant and support structure forming longitudinally-extending, annular air spaces between said layers, and

heating simultaneously said finally formed, partially cured solid propellant and said support structure to a fully cured, structurally rigid state.

2. The invention as set forth in claim 1 wherein said solid propellant ammonium perchlorate oxidized composition containing a binder is comprised of 80 percent ammonium perchlorate and 18 percent carboxy-terminated polybutadiene binder with a benzene carboxamide curative, and wherein said uncured, reinforced fabric tape with a thermo-setting resin is an epoxy-fiberglass tape.

3. The invention as set forth in claim 2 wherein said solid propellant on both sides of said support structure is partially cured to a gelled state for 12 hours ±

0.5 hour, at approximately 170°

F, after which said gelled solid propellant on said support structure is spirally formed into a final grain configuration, said solid propellant and said support structure being simultaneously cured for 4 hours, ±

0.5 hour, at approximately 300°

F.

4. The invention as set forth in claim 1 wherein said solid propellant binder system is selected from the group consisting of carboxy-terminated polybutadiene, polybutadiene acrylic acid, and polybutadiene acrylonitrile.

5. The invention as set forth in claim 1 wherein said thermosetting resin binder on said reinforced fabric tape is selected from the group consisting of epoxy, phenolic ureaformaldehyde, resorcinal, and polyacrylate.