The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 05, 1978
Filed:
Dec. 01, 1977
Marjorie T Cucksee, Huntsville, AL (US);
Henry C Allen, Decatur, AL (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
A method of mixing poly(neopentylglycol)azelate (NPGA) is disclosed which hances its solubility in polyurethane binders for composite solid propellants. The method comprises withholding the addition of NPGA from the propellant submix and from the total propellant formulation mixing procedure until after the addition of the curing agent has taken place and reaction has taken place for a predetermined period of time with the bonding agent until a 'break' in viscosity occurs. The 'break' in viscosity has taken place when the other binder ingredients have reacted with the curing agent HDI (hexamethylenediisocyanate) so that immiscibility between the binder ingredients is reduced. The late NPGA addition method resulted not only in apparently complete solubilization of the NPGA but also yielded a propellant with dramatically lower end of mix viscosity (reduced by a factor of 10), superior flow characteristics, and better physical properties. Propellants made by the disclosed method of mixing have desirable lower modulus and higher tensile strength. Thus, the propellant mixed in accordance with the late NPGA addition method yields a propellant with a high tensile strength to modulus ratio. The high tensile strength to modulus ratio at low temperature is an indicator of a good propellant.