Dimer isocyanate liner compositions
AssigneeAerojet-General Corporation
InventorJohn M. Wrightson
Life of this patent
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Abstract
A composition is disclosed in which a solid isocyanate compound such as toluene-diisocyanate dimer is dispersed within a polyurethane based on a hydroxy-terminated organic compound, preferably polybutadiene. The composition can be fully cured on a surface and yet provides an excess of stable material, i.e. dormant isocyanate containing groups, which are reactive on demand to strengthen interfaces with adjacent layers containing available hydroxyl groups, such as a layer of solid polyurethane-based propellant, without the need for intermediate reactive coatings.
Claims26
A method of improving the adherence of a layer of a first composition containing organic active hydrogen compounds to a surface comprising the steps of:
- applying to said surface a film of a composition comprising polyurethane forming components having dispersed therein a stable, solid polyisocyanate precursor additive in an amount in excess of the amount necessary to form the polyurethane and which is reactive after cure of the composition with said compounds;
- curing said composition to form a polyurethane film containing excess stable, solid polyisocyanate precursor additive;
- applying said layer to said film;
- and
- curing said layer and reacting said active hydrogen compounds with said excess additive to form bonds binding said film to said layer.
A method of improving the adherence of a solid rocket propellant to a rocket motor casing containing the propellant which comprises:
- applying to said casing a layer of a composition comprising polyurethane forming components having dispersed therein a stable, solid polyisocyanate precursor additive in an amount in excess of the amount necessary to form the polyurethane, which excess is reactive, after cure of the composition, with organic active hydrogen compounds;
- curing said composition to form a polyurethane liner containing excess additive;
- applying to said polyurethane liner a layer of a curable propellant composition containing organic active hydrogen compounds;
- and
- curing said propellant composition and reacting said active hydrogen compounds with said excess additive to form a solid rocket propellant having bonds binding said propellant to said liner.
An assembly having improved bonding between layers comprising in combination:
- a first layer comprising polyurethane formed by cure of a first composition comprising polyurethane forming components in which is dispersed a stable, solid polyisocyanate precursor additive in excess of the amount necessary to form said polyurethane and which excess additive is reactive after cure of the composition with organic active hydrogen compounds;
- and
- a second layer adhered to said first layer, said second layer being formed by applying a second composition containing organic active hydrogen compounds to said first layer and curing said second composition, said active hydrogen compounds being reacted with said excess additive to form interfacial bonds between said layers.
A solid propellant rocket motor comprising:
- a casing;
- a cured polyurethane liner within said casing formed by cure of a liner composition comprising polyurethane forming components in which is dispersed a stable, solid polyisocyanate precursor additive in excess of the amount necessary to form said polyurethane and which is reactive, after cure of the composition, with organic active hydrogen compounds;
- and
- propellant adhered to said liner formed by applying to said liner a propellant composition containing organic active hydrogen compounds and curing said propellant composition and reacting said active hydrogen compounds with said excess additive to form interfacial bonds between said liner and said propellant.
Dependencies are inferred from the claim text.