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EP-3433086-B1 - ENERGETIC MATERIALS

EP3433086B1EP 3433086 B1EP3433086 B1EP 3433086B1EP-3433086-B1

Inventors

  • Straathof, Michiel Hannes
  • VAN DRIEL, CHRISTOFFEL ADRIANUS
  • TEN CATE, AAFKE TESSA

Dates

Publication Date
20260506
Application Date
20170322

Claims (15)

  1. Radiation curable energetic composition, comprising (a) 5-45 % by total weight of the composition of one or more polymerisable components, (b) 0.05-3 % by total weight of the composition of one or more polymerisation photoinitiators, (c) 30-95 % by total weight of the composition of one or more energetic components, and (d) 10-40 % by total weight of the composition of one or more energetic plasticisers selected from the group consisting of alkyl ethyl nitramines, N-(2-nitroxyethyl)nitramine (NO 2 -N-CH 2 CH 2 ONO 2 ) and homologs thereof, including N-(2-nitroxyethyl) methylnitramine, N-(2-nitroxyethyl) ethylnitramine, N-(2-nitroxyethyl) n-propylnitramine, N-(2-nitroxyethyl) n-butylnitramine, N-(2-nitroxypropyl) methylnitramine, N-(2-nitroxyethyl) cyclohexylnitramine, dinitroxydiethyl nitramine, nitroglycerin, 1,2,4-butane triol trinitrate, 1,5-diazido-3-nitrazapentane, triethyleneglycol dinitrate, and diglycol dinitrate, wherein said polymerisable components comprise (a1) one or more free radical polymerisable components, and said polymerisation photoinitiators comprise (b1) one or more polymerisation photoinitiators for free radical polymerisation, and/or wherein said polymerisable components comprise (a2) one or more cationically polymerisable components, and said polymerisation photoinitiators comprise (b2) one or more polymerisation photoinitiators for cationic polymerisation.
  2. Radiation curable energetic composition according to claim 1, wherein said one or more polymerisable components comprise fuel and oxidiser.
  3. Radiation curable energetic composition according to claim 1 or 2, wherein said radical polymerisable components comprise one or more selected from the group consisting of an aliphatic (meth)acrylate, an aromatic (meth)acrylate, a cycloaliphatic (meth)acrylate, an arylaliphatic (meth)acrylate, and a heterocyclic (meth)acrylate.
  4. Radiation curable energetic composition according to any one of claims 1-3, wherein said cationically polymerisable component comprises one or more selected from the group consisting of cyclic ether compounds, cyclic acetal compounds, cyclic thioether compounds, spiro-orthoester compounds, cyclic lactone compounds, and vinyl ether compounds, wherein more preferably said cationically polymerisable component comprises one or more selected from the group consisting of a diglycidyl ether compound, an epoxy compound, and an oxetane compound.
  5. Radiation curable energetic composition according to any one of claims 1-4, wherein at least part of said energetic component comprises one or more selected from the group consisting of 2,4,6-trinitrotoluene (TNT), cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), cyclotetramethylenetetranitramine (HMX), pentaerythrol tetranitrate (PETN), 3-nitro-1,2,4-triazol-5-one (NTO), nitroglycerine (NG), nitrocellulose (13 % N) (NC), ammonium nitrate (AN), ammonium perchlorate (AP), 2,4,6,8,10,12-(hexanitro-hexaaza)tetracyclododecane (CL20 or HNIW), 1,3,3-trinitroazetidine (TNAZ), octanitrocubane (ONC), 1,1-diamino-2,2-dinitroethene (FOX-7), ammonium dinitramide (ADN), 2,2,2-trinitroethylacrylate, 2,2,2-trinitroethylmethacrylate (TNEM), 2,2-dinitropropylacrylate (DNPA), 2-nitroethylacrylate, and pentaerythritoltrinitrate acrylate.
  6. Radiation curable energetic composition according to any one of claims 1-5, wherein at least part of said energetic components are polymerisable components.
  7. Radiation curable energetic composition according to any one of claims 1-6, wherein at least part of said energetic component is solid, and wherein said solid energetic component is preferably in the form of particulates having an average particle size as determined by laser diffraction of 0.5-100 µm, more preferably 1-60 µm, even more preferably 2-40 µm, such as 2-10 µm.
  8. Radiation curable energetic composition according to any one of claims 1-7, wherein said at least part of said energetic component is radiation curable.
  9. Radiation curable energetic composition according to any one of claims 1-8, further comprising a hydroxy functional component.
  10. Radiation curable energetic composition according to any one of claims 1-9, comprising - 10-40 % by total weight of the composition of polymerisable components, preferably 15-35 %; - 0.1-2 % by total weight of the composition of polymerisation photoinitiators, preferably 0.2-1.5 %; - 40-95 % or more by total weight of the composition of energetic components, preferably 45-90 %; and - 0-10 % by total weight of the hydroxy functional component, preferably 0.5-8 %, more preferably 1-5 %.
  11. Radiation curable energetic composition according to any one of claims 1-10, further comprising one or more dyes and/or pigments, wherein the amount of said dyes and/or pigments in the radiation curable energetic composition is preferably 0-0.1 % by total weight of the composition, more preferably 0.005-0.02 %.
  12. Radiation curable energetic composition according to any one of claims 1-11, further comprising one or more selected from photosensitisers, fillers, stabilisers, antioxidants, wetting agents, defoamers, and surfactants.
  13. Method of forming a three-dimensional energetic object comprising the steps of forming and selectively curing a layer of the radiation curable energetic composition according to any one of claims 1-12 with actinic radiation and repeating the steps of forming and selectively curing a layer of the radiation curable energetic composition according to any one of claims 1-12 a plurality of times to obtain a three-dimensional energetic object.
  14. A three-dimensional energetic object formed from the radiation curable energetic composition according to any one of claims 1-12 or by the method of claim 13.
  15. Use of a radiation curable energetic composition according to any one of claims 1-12 in ballistics, pyromechanical devices, fireworks or propellant rockets.

Description

The invention is directed to a radiation curable energetic composition, to a method of forming a three-dimensional energetic object, to a three-dimensional energetic object, and to uses of the radiation curable energetic composition. Propellant charges are used in pyrotechnics and ballistics in order to accelerate a piston or a projectile. Typically, the propellant charge is ignited by a primer, which is a small amount of sensitive explosive. Gases produced by combustion of the propellant charge cause a rapid build-up of pressure. When a certain pressure is reached, the projectile begins to move, thereby causing an increase in chamber volume. After a pressure maximum is reached, typically the pressure decreases relatively rapidly due to the expansion of the chamber volume. A propellant charge is an amount of relatively insensitive but powerful energetic material that propels the projectile out of the gun barrel. Various types of propellant charges having different composition and geometries are used for different applications and purposes. The propellants used are typically solid. Examples of propellants that are in use today include gun powders, including smokeless powders. Smokeless powders may be considered to be classed as either single or multi-base powders. Conventional smokeless powders consist mainly of nitrocellulose. Typical production processes include drying of water-wet nitrocellulose, mixing and kneading with ether and alcohol and other constituents, pressing the propellant dough through a die, cutting the obtained strand into propellant grains, and drying these grains.. Although called powders, they are not in powder form, but in granule form. In single-base propellants, nitrocellulose is the main energetic material present. Other ingredients and additives are added to obtain suitable form, desired burning characteristics, and stability. The multi-base propellants may be divided into double-base and triple-base propellants, both of which contain typically nitroglycerin to facilitate the dissolving of the nitrocellulose and enhance its energetic qualities. The nitroglycerin also increases the sensitivity, the flame temperature, burn rate, and tendency to detonate. The higher flame temperature serves to decrease the smoke and residue, but increases flash and gun-tube erosion. Triple-base propellants are double-base propellants with the addition of nitroguanidine to lower the flame temperature, which produces less tube erosion and flash. The major drawback is the limited supply of the raw material nitroguanidine. In the multi-base propellants, the multiple ingredients are evenly distributed in the propellant charge. Once ignition is achieved, it is desirable to have the propellant burn in a controlled manner from the surface of the propellant charge inwardly. As the propellant is initially ignited and gases are being generated, the projectile is either at rest or moving relatively slowly. Thus, gases are being generated faster than the volume of the chamber is increasing. As a result of this, the pressure experienced increases. As the projectile accelerates, the volume of the chamber increases at a rate which ultimately surpasses the rate of gas generation by the burning of the propellant material. The transition corresponds to the point of maximum pressure in the combustion chamber. Thereafter the pressure decreases as the projectile continues to accelerate thus increasing the volume of the chamber at a rate faster than the increase in volume of gases being generated by the propellant burn. Solid propellants are designed to produce a large volume of gases at a controlled rate. Gun barrels and some rocket casings are designed to withstand a fixed maximum gas pressure. The pressure generated can be limited to this maximum value by controlling the rate of burning of the propellant. In the art, the burn rate is controlled by varying the following factors: (1) the size and shape of the grain, including perforations,(2) the web thickness or amount of solid propellant between burning surfaces; the thicker the web, the longer the burning time.,(3) the linear burn rate, which depends on the gas pressure and the chemical composition of the propellant, including volatile materials, inert matter, and moisture present. When a propellant burns in a confined space, the rate of burning increases as both temperature and pressure rise. Since propellants burn only on exposed surfaces, the rate of gas evolution or changes in pressure will also depend upon the area of propellant surface ignited. The use of perforations in a propellant charge so as to control the rate of burning is for instance known from US-A-4 386 569. This patent is based on the insight that the burn rate of the propellant material, i.e. the burn characteristics of the propellant charge, not only depends on the physical and chemical characteristics of the propellant material itself, but also depends on the shape of the propellant charge. US-A-4 3