Manufacture of propellant compositions and propellant charges
First Claim
1. A process for the manufacture of a rubbery propellant charge which comprises the steps:
- of forming a plastic propellant composition comprising a solid particulate propellant and a binder forming from 5% to 25% by weight of the composition, said binder comprising a prepolymer, comprising a functionally terminated hydrocarbon chain or a co-polymer thereof, of a kind capable of being chain extended by curing into a rubbery elastomeric state, said prepolymer having been partially cured by an organic cross-linking agent so as to have an apparent viscosity in the range 2,000 to 20,000 poise at 25 degrees C.;
further treating said plastic composition with a curing agent adapted to complete the cure of said binder into said rubbery state; and
prior to curing of said binder by said curing agent, forming said plastic propellant composition into a propellant charge by a dynamic forming process in which said plastic propellant composition is shaped into said propellant charge.
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Accused Products
Abstract
This invention relates to the manufacture of composite propellants containing rubbery binders and particulate non-binder ingredients. The process consists of curing a mixture of a functionally-terminated hydro-carbon prepolymer and a cross-linking agent to form a viscoelastic first binder composition, mixing the binder with non-binder ingredients to form a plastic propellant, and rubberising at least a part of the plastic propellant by adding to it a further quantity of the cross-linking agent, provided the propellant is formed into a propellant charge while still in a plastic state. The further quantity of the cross-linking agent may be mixed in with the plastic propellant prior to forming, or applied to the surface of the plastic propellant after having been formed into a charge.
In a preferred embodiment of the invention, the prepolymer consists of an hydroxy-terminated polybutadiene having a molecular weight of about 3000 and a functionally of about 2.2, and the cross-linking agent consists of isophorone diisocyanate.
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Citations
18 Claims
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1. A process for the manufacture of a rubbery propellant charge which comprises the steps:
- of forming a plastic propellant composition comprising a solid particulate propellant and a binder forming from 5% to 25% by weight of the composition, said binder comprising a prepolymer, comprising a functionally terminated hydrocarbon chain or a co-polymer thereof, of a kind capable of being chain extended by curing into a rubbery elastomeric state, said prepolymer having been partially cured by an organic cross-linking agent so as to have an apparent viscosity in the range 2,000 to 20,000 poise at 25 degrees C.;
further treating said plastic composition with a curing agent adapted to complete the cure of said binder into said rubbery state; and
prior to curing of said binder by said curing agent, forming said plastic propellant composition into a propellant charge by a dynamic forming process in which said plastic propellant composition is shaped into said propellant charge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
- of forming a plastic propellant composition comprising a solid particulate propellant and a binder forming from 5% to 25% by weight of the composition, said binder comprising a prepolymer, comprising a functionally terminated hydrocarbon chain or a co-polymer thereof, of a kind capable of being chain extended by curing into a rubbery elastomeric state, said prepolymer having been partially cured by an organic cross-linking agent so as to have an apparent viscosity in the range 2,000 to 20,000 poise at 25 degrees C.;
Specification