초록 ▼

A robust polyurethane liner is disclosed for solid propellant rocket motors which is insensitive to large variations in stoichiometry, exhibits increased cohesive strength and, when used in combination with a unique two coat (wet coat) liner process described below, modifies the ballistic properties

A robust polyurethane liner is disclosed for solid propellant rocket motors which is insensitive to large variations in stoichiometry, exhibits increased cohesive strength and, when used in combination with a unique two coat (wet coat) liner process described below, modifies the ballistic properties of the adjacent interfacial propellant layer. The liner compositions include a polymeric binder having a plurality of reactive hydroxyl functional groups and a curing agent having a plurality of reactive isocyanate functional groups. The quantity of binder and curing agent is selected such that the NCO/OH ratio is in the range from 1.5 to 4.5. Diisocyanate curing agents are particularly useful. A bonding agent, such as a polyfunctional aziridine compound, is typically present in the liner composition in an amount ranging from about 3% to about 5%, by weight. An oligomer catalyst is included in the liner composition in an amount ranging from about 15% to about 50%, by weight. Diammonium phosphate ((NH.sub.4).sub.2 HPO.sub.4) functions as an oligomer catalyst and as a ballistic modifier to inhibit propellant burn rate when the liner is cured concurrently with the propellant. A colorant, such as rhodamine B, may optionally be included to assist in determining coverage or thickness of the liner coating.

대표청구항 ▼

[ The claimed invention is:] [1.] A method of lining a rocket motor chamber interior and of controlling interfacial propellant burn rate of a solid propellant cast therein comprising the steps of:(a) applying at least one coat of a first liner composition to the rocket motor chamber interior, wherei

[ The claimed invention is:] [1.] A method of lining a rocket motor chamber interior and of controlling interfacial propellant burn rate of a solid propellant cast therein comprising the steps of:(a) applying at least one coat of a first liner composition to the rocket motor chamber interior, wherein the first liner composition comprises:a polymeric binder having a plurality of reactive hydroxyl functional groups and a curing agent having a plurality of reactive isocyanate functional groups; anda bonding agent present in the first liner composition in an amount ranging from about 3% to about 5%, by weight; and(b) at least partially curing the coat of the first liner composition;(c) applying at least one coat of a second liner composition to the rocket motor chamber interior, wherein the second liner composition comprises:a polymeric binder having a plurality of reactive hydroxyl functional groups and a curing agent having a plurality of reactive isocyanate functional groups;a bonding agent present in the second liner composition in an amount ranging from about 3% to about 5%, by weight;a burn rate modifier present in the second liner composition in an amount ranging from about 5% to about 50%, by weight; and(d) casting a solid rocket propellant within the rocket motor chamber before curing the second liner composition such that intermixing of the second liner composition and adjacent rocket propellant occurs.