Ammunition articles comprising light-curable moisture-preventative sealant and method of manufacturing same
A process for manufacturing an ammunition article, including: (a) providing a cartridge including a projectile disposed in a casing and presenting a joint between the projectile and the casing; (b) applying to the joint a sealingly effective amount of a light-curable sealant composition; and (c) exposing the applied sealant composition to curingly effective light. The resulting ammunition article is sealed at the projectile/casing joint against moisture incursion, and such article is amenable to high-speed, high-volume production by the method of the invention.
1. A process for manufacturing an ammunition article, comprising:
(a) providing a cartridge including a projectile disposed in a casing and presenting a joint between the projectile and the casing;
(b) applying to the joint a sealingly effective amount of a light-curable sealant composition, wherein the light-curable sealant composition (i) is not capillarily active at the joint, (ii) has a viscosity in a range from about 75 to 1000 centipoise at 25° C., and (iii) is UV-curable in exposure to ultraviolet radiation, curingly effective light therefor, within a time period of from about 0.01 to about 0.5 second, wherein a force of between 45 and 200 pounds is required to be applied to separate said projectile from said casing after cure of the light-curable sealant composition, and wherein the light-curable sealant composition is not anaerobically curing; and
(c) exposing the applied sealant composition to curingly effective light comprising said UV radiation for a time period of from about 0.01 to about 0.5 second.
2. The process of claim 1 , wherein applying to the joint the sealingly effective amount of the light-curable sealant composition involves relative motion of the cartridge and an applicator dispensing the light-curable sealant composition to the joint.
3. The process of claim 2 , wherein the cartridge is motively translated in relation to the applicator.
4. The process of claim 2 , wherein the applicator is motively translated in relation to the cartridge.
5. The process of claim 2 , wherein the applicator comprises an application device selected from the group consisting of syringe pump dispensers, roller coaters, doctor blades, needle dispensers, and liquid-fed transfer devices.
6. The process of claim 2 , wherein the light-curable sealant composition comprises a liquid sealant and the applicator comprises a liquid-fed transfer device selected from the group consisting of liquid-fed brushes, sponges, swabs, pads, and cuffs, coupled in dispensing relationship with a reservoir for supply of the liquid sealant.
7. The process of claim 1 ,
wherein applying to the joint the sealingly effective amount of the light-curable sealant composition involves relative motion of the cartridge and an applicator dispensing the light-curable sealant composition to the joint,
wherein the applicator comprises a needle dispenser, in combination with a wiper element as a follower behind the needle dispenser, arranged to exert a squeegee action on sealant dispensed from the needle dispenser and to remove excess applied sealant, and
wherein the applied sealant composition is non-capillarily active at the joint.
8. The process of claim 1 , wherein the curingly effective light comprises ultraviolet light.
9. The process of claim 8 , wherein the ultraviolet light has a wavelength in a range of from about 220 to about 375 nanometers.
10. The process of claim 1 , wherein the curingly effective light is supplied by a source including a light-generating component selected from the group consisting of lamps, LEDs, photoluminescent media, down-converting and up-converting materials that respond to incident radiation in one electromagnetic spectral regime and responsively emit radiation of a longer or shorter wavelength, respectively, electrooptical generators, and lasers.
11. The process of claim 1 , wherein the sealant composition after exposure to a curingly effective actinic radiation, does not fluoresce.
12. The process of claim 1 , wherein the light-curable sealant composition comprises a photocurable resin selected from the group consisting of unsaturated polyesters, epoxies, (meth)acrylates, urethane (meth)acrylates, (meth)acrylic ester monomers, oligoester acrylate-based compounds, epoxy acrylate-based compounds, polyimide-based compounds, aminoalkyd-based compounds, and vinyl ether-based compounds.
13. The process of claim 1 , wherein the light-curable sealant composition comprises a photocurable resin selected from the group consisting of bisphenol epichiorohydrin epoxy resins, acrylic resins, urethane acrylate resins, acrylated polyester resins, and cycloaliphatic epoxides.
14. The process of claim 1 , wherein the light-curable sealant composition comprises a photocurable resin and a photoinitiator therefor.
15. The process of claim 1 , wherein the light-curable sealant composition comprises a formulation selected from the group consisting of free-radical curable acrylate resin-based formulations, and cationically curable epoxy-based formulations.
16. The process of claim 1 , wherein the light-curable sealant composition comprises a free-radical curable acrylate resin-based formulation.
17. The process of claim 1 , wherein the light-curable sealant composition comprises a catianically curable epoxy-based formulation.
18. The process of claim 1 , wherein the light-curable sealant composition comprises a monomeric diluent.
19. The process of claim 1 , wherein the light-curable sealant composition comprises a neat formulation of resin and photoinitiator.
20. The process of claim 1 , wherein the light-curable sealant composition comprises a dye.
21. The process of claim 1 , wherein the light-curable sealant composition comprises a photoinitiator in a concentration not exceeding 5% by weight, based on total weight of the composition.
22. The process of claim 1 , wherein after exposure to the curingly effective light, the projectile is separable from the casing by a tensile force that is no more than 10% greater than a tensile force required to separate the projectile from the casing when the light-curable sealant composition is absent.
23. The process of claim 1 , wherein after exposure to the curingly effective light, the projectile is separable from the casing by a tensile force that is no more than 5% greater than a tensile force required to separate the projectile from the casing when the light-curable sealant composition is absent.
24. An ammunition article made by the process of claim 1 including a projectile mounted in a cartridge casing presenting a projectile/casing interface, with the interface sealed by a light-cured sealant composition.