JP2007537967A - Stable initiator composition and igniter - Google Patents

Abstract

A high spark initiator composition (718) with reduced power is disclosed. The initiator composition includes a metal-containing oxidizer, at least one metal reducing agent, and a non-explosive binder. Also disclosed is a low voltage igniter that produces a jet in both directions upon ignition. These igniters have an electrical resistance element (716) positioned across a hole (713) in a support (712) that defines the direction of ejection. These igniters and compositions are useful for actuation of solid fuel heating units, particularly hermetic heating units.
[Selection] Figure 1

Description

Field

  [0001] The present disclosure relates to low outgassing initiator compositions and jet induction igniters, and more particularly to initiator compositions and igniters used in hermetic heating units that heat solid fuel.

Introduction

  [0002] Built-in heating units are used in a wide range of industries, from the food industry for heating food and beverages to outdoor recreation providing hand and foot warmers, and medical applications for inhalation devices. These built-in heating units are heated by various mechanisms including an exothermic chemical reaction. A chemical-based heating unit may include a solid fuel that undergoes an exothermic metal redox reaction within an enclosure, such a heating unit being, for example, filed on May 20, 2004, whose title is “ Self-Contained Heating Unit and Drug-Supply Unit Employing Same ", the entire contents of which are expressly incorporated herein by reference for all purposes.

  [0003] Solid fuel is ignited to produce a self-supporting redox reaction. When a portion of the solid fuel is ignited, the heat generated by the redox reaction ignites the nearby unburned fuel until all of the fuel is consumed in the chemical reaction process. The exothermic redox reaction is initiated by supplying energy to at least a portion of the solid fuel. The energy absorbed by the solid fuel or the element in contact with the solid fuel is converted into heat. When the solid fuel is heated to a spontaneous ignition temperature of the reaction, e.g., above the minimum temperature required to initiate or induce self-sustaining combustion in the absence of a combustion source or flame, the redox reaction begins and the fuel is consumed. Burn solid fuel in a self-supporting reaction until

  [0004] Energy is supplied to ignite solid fuel using a number of methods. For example, a resistive heating element capable of heating solid fuel to a spontaneous ignition temperature when current is supplied is positioned in thermal contact with the solid fuel. An electromagnetic radiation source capable of heating the solid fuel to its pyrophoric temperature when absorbed is directed to the solid fuel. Electromagnetic radiation sources include lasers, diodes, flash lamps, and microwave sources. RF or induction heating heats the solid fuel source by applying an alternating RF magnetic field that is absorbed in the solid fuel or absorbed by a material with high permeability that is in thermal contact with the solid fuel. The energy source is concentrated in the absorbent material to produce a higher local temperature and consequently increase the energy density to promote ignition. In some embodiments, the solid fuel is ignited by an impact force.

  [0005] A metal reducing agent and a metal-containing agent as described in a US patent application filed on May 20, 2004, entitled "Self-Contained Heating Unit and Drug-Supply Unit Employing Same" The spontaneous ignition temperature of the solid fuel containing the oxidizer varies from 400 ° C to 500 ° C. Such a high pyrophoric temperature promotes the safe processing and safe use of solid fuels under many conditions of use, for example, as a portable medical device, but for the same reason to achieve such high temperatures In addition, a large amount of energy must be supplied to the solid fuel to initiate a self-supporting reaction. Furthermore, the thermal mass represented by the solid fuel requires that an unrealistic high temperature must be applied to raise the temperature of the solid fuel above the pyrophoric temperature. When heat is applied to the solid fuel and / or the support on which the solid fuel is disposed, the heat is simultaneously conducted and discharged. Direct heating of the solid fuel requires a significant amount of power due to the thermal mass of the solid fuel and support.

  [0006] As is well known in the art, for example, in the fireworks industry, sparks are used to ignite fuel compositions safely and efficiently. Spark refers to the electrical breakdown of dielectric media or the emission of combustion particles. In the first sense, electrical breakdown is generated, for example, between separate electrodes to which a voltage is applied. Sparks can also be generated by ionizing compounds in an intense laser field. Examples of burning particles include particles generated by friction and intermittent sparks generated by intermittent current. Sparks with sufficient energy incident on the solid fuel initiate a self-supporting redox reaction.

  [0007] Typically, initiator compositions used to operate devices that contain solid fuel, particularly in the field of fireworks, contain lead compounds. The reason why lead compounds are used in the initiator composition is that the lead compounds give the composition a high thermal stability and start reliably with very weak energy stimuli such as spark or resistance heating. In recent years, ignition devices having initiator compositions that do not contain lead have been described. For example, Naud et al., International Publication No. 2004/011396, describes an electrical match using energetic material and binder nanoparticles. However, the initiator compositions used for the electronic match described in Naud et al., And other initiator compositions for such purposes, typically have the desired spark sensitivity, spark strength, and In order to provide the required strength, it includes multiple layers of different materials. Additionally, the latest commercially available electrical match compositions contain explosive materials such as nitrocellulose. In addition, these materials tend to generate significant amounts of gas upon ignition.

  [0008] Ignition devices on which these initiator compositions are installed generally consist of an electrically insulating substrate coated with copper foil. The substrate size is typically approximately 0.4 inches long, 0.1 inches wide, and 30 mils thick. A small-diameter nichrome wire is soldered to the end of the match so as to cross the edge of the match. Insulative leads soldered to the base of the match provide a means to electrically ignite the nichrome wire to generate the initial spark. The spark blast generated from such an igniter is typically in the shape of a flame, like a match flame, and directed in one direction.

  [0009] The initiator composition and igniter described above are capable of producing a high spark blow. However, it is not only a high spark, but also a low outgassing due to the sealing system, and explosiveness as classified by the US Department of Transportation for use in medical, food, and other such devices There is still a need for initiator compositions that do not include materials. In addition, there is a need for an igniter that provides ejection in both directions.

Overview

  [0010] Accordingly, it is an object of the present invention to provide an initiator composition that is capable of producing high spark, but is low outgassing and has a defined amount of power. More desirably, these compositions are such that they are ignited by electrical resistance, impact, and / or optical ignition.

  [0011] Another object of the present invention is to provide an electrical resistance igniter that produces a bidirectional jet upon ignition. In some embodiments, the igniter is coated with a high spark initiator composition.

  [0012] In one aspect, the present invention provides a deflagration for a sealed heating unit or other system where low gas production is desired, comprising a mixture of a metal-containing oxidant, at least one metal reducing agent, and a binder. An initiator composition is provided. The binder is typically non-explosive. The power is sufficient to ignite the solid fuel, but optimized to deliver energy that is not strong enough to damage the solid fuel surface when coated as a thin layer on the surface Yes.

  [0013] Another aspect of the present invention comprises a support comprising a hole therein and at least two in contact with the support, wherein the initiator composition is placed over and positioned across the hole to cover the hole. An ignition device including a resistance heating element connected to a conductor and igniting fuel using spark jets concentrated in both directions is provided.

  [0014] In yet another aspect of the present invention, a method of making an igniter with bi-directional ejection is provided.

  [0015] It is understood that both the above general description and the following detailed description are exemplary and explanatory only and are not restrictive of certain embodiments as recited in the claims. Should be.

Description of various embodiments

  [0026] Unless stated otherwise, all numbers expressing amounts of inclusions, reaction conditions, etc. used in the specification and claims are understood to be modified in all cases by the term “about”. It should be.

  [0027] In this application, the use of the singular includes the plural unless specifically stated otherwise. In this application, the use of “or” includes “and / or” unless stated otherwise. Furthermore, the use of the terms “including” and other forms such as “includes” and “included” is not limiting. Similarly, terms such as “element” or “component” encompass both elements and components comprising one unit and elements and components comprising two or more subunits, unless otherwise specified.

Initiator composition
[0028] In order to ignite fuel, particularly fuel coated on a substrate, the igniter should provide optimal power to the fuel. If the power released when igniting the initiator composition is insufficient, the heat delivered to the fuel is dissipated by heat conduction before the fuel ignites. If the power is too strong, the spark generated from the ignition composition will destroy the surface of the fuel film, resulting in uneven heating of the fuel coated surface. In some applications, such as a heating unit for dispensing medication as a compressed aerosol, this heating non-uniformity affects the purity of the resulting aerosol. Moreover, it is desirable that these heating units be operated using a low voltage if possible, so as to reduce the cost reasons and the size of the drug spreader with the heating unit and battery.

  [0029] The initiator composition of the present invention detonates and produces a strong spark that ignites solid fuels easily and reliably, but does not destroy the surface of the fuel. The initiator composition is very reliable and includes a mixture of a metal-containing oxidizing agent and at least one metal reducing agent.

  [0030] In certain embodiments, the metal reducing agent is molybdenum, magnesium, calcium, strontium, barium, boron, titanium, zirconium, vanadium, niobium, tantalum, chromium, tungsten, manganese, iron, cobalt, nickel, copper, zinc. Including, but not limited to, cadmium, tin, antimony, bismuth, aluminum, and silicon. In some embodiments, the metal reducing agent includes aluminum, zirconium, and titanium. In some embodiments, the metal reducing agent includes two or more metal reducing agents.

[0031] In certain embodiments, the oxidant comprises oxygen, an oxygen-based gas, and / or a solid oxidant. In certain embodiments, the oxidant includes a metal-containing oxidant. In some embodiments, the metal-containing oxidant includes, but is not limited to, perchlorate and transition metal oxide. Examples of perchlorates include potassium perchlorate (KClO ₄ ), potassium chlorate (KClO ₃ ), lithium perchlorate (LiClO ₄ ), sodium perchlorate (NaClO ₄ ), and magnesium perchlorate [ Including alkali metal or alkaline earth metal perchlorates such as, but not limited to, Mg (ClO ₄ ) ₂ ]. In some embodiments, the transition metal oxide that functions as an oxidant is an oxide of molybdenum (eg, MoO ₃ ), an oxide of iron (eg, Fe ₂ O ₃ ), an oxide of vanadium (V ₂ O ₅ ). , Chromium oxide (CrO ₃ , Cr ₂ O ₃ ), manganese oxide (MnO ₂ ), cobalt oxide (Co ₃ O ₄ ), silver oxide (Ag ₂ O), copper oxide ( CuO), tungsten oxide (WO ₃ ), magnesium oxide (MgO), and niobium oxide (Nb ₂ O ₅ ), but are not limited thereto. In some embodiments, the metal-containing oxidant includes two or more metal-containing oxidants.

  [0032] In certain embodiments, the metal reducing agent and oxidizing agent may be in powder form. The term “powder” refers to powders, particles, globules, flakes, and other particulates that exhibit an appropriate size and / or surface area to maintain self-propagating combustion. For example, in certain embodiments, the powder includes particles that exhibit an average diameter that varies from 0.01 μm to 200 μm.

  [0033] In certain embodiments, the amount of oxidant in the initiator composition is related to the molar amount of oxidant at or near the eutectic point of the fuel composition. In some embodiments, the oxidizing agent is the major component, and in other embodiments, the metal reducing agent is the major component. As is known in the art, the particle sizes of metals and metal-containing oxidants are varied to determine the burn rate, and smaller particle sizes are selected for fast combustion (eg, PCT International Publication No. 2004/01396). Thus, in some embodiments where fast combustion is desired, the particles are preferably nano-sized.

  [0034] In certain embodiments, the amount of metal reducing agent varies from 25% to 75% by weight of the total dry weight of the initiator composition. In certain embodiments, the amount of metal-containing oxidant varies from 25% to 75% by weight of the total dry weight of the initiator composition.

  [0035] In some embodiments, the initiator composition comprises at least one metal as described herein and an alkali metal or alkaline earth, for example, as described herein. And at least one oxidizing agent such as metal chlorate or perchlorate or metal oxide.

  [0036] In certain embodiments, the initiator composition comprises at least one metal reducing agent from the group consisting of aluminum, zirconium and boron. In certain embodiments, the initiator composition comprises at least one oxidant from the group consisting of molybdenum trioxide, copper oxide, tungsten trioxide, potassium chlorate, and potassium perchlorate.

  [0037] In certain embodiments where ease of handling is preferred, aluminum is a preferred metal reducing agent. Aluminum has several advantages, including being available in various sizes such as nanoparticles and easily forming a protective oxide coating. Thus, aluminum can be purchased and handled in a dry state. Moreover, aluminum is handled more safely because it is less pyrophoric than other metal oxidants such as zirconium.

  [0038] In certain embodiments, the composition comprises two or more metal reducing agents. In such compositions, the at least one reducing agent is preferably boron. Boron has been used in other initiator compositions (see, eg, US Pat. Nos. 4,484,960 and 5,672,843). Boron increases the rate at which detonation occurs in order to provide more heat output in the presence of an oxidant.

  [0039] In certain embodiments, reliable, reproducible and controlled solid fuel ignition comprises at least a metal-containing oxidant, at least one metal reducing agent, a gelling agent and / or a binder. This is facilitated by the use of an initiator composition comprising a mixture with one binder and / or additive material. The initiator composition includes the same or similar reactants as the composition comprising the solid fuel.

[0040] In some embodiments, the initiator composition includes additive materials to, for example, facilitate processing, increase mechanical integrity, and / or determine combustion and spark generation characteristics. The inert additive material does not react during the ignition and combustion of the initiator composition or reacts to a minimum extent. This is particularly advantageous when working with sealing systems where minimization of gas accumulation is desired. The additive material may be an inorganic material and functions as a binder, an adhesive, a gelling agent, a thixotropic agent, and / or a surfactant. Examples of gelling agents include clays such as Laponite (R), montmorillonite, Cloisite (R), n is 3 or 4, M is Ti, Zr, Al, B or other materials And includes, but is not limited to, metal alkoxides as represented by the chemical formulas R—Si (OR) _n and M (OR) _n and colloidal particles based on transition metal hydroxides or oxides. Examples of binding agents include soluble silicates such as sodium silicate or potassium silicate, aluminum silicates, metal alkoxides, inorganic polyanions, inorganic polycations, and sols based on alumina or silica. Inorganic sol / gel materials are included, but not limited thereto. Other useful additives include glass balls, diatomaceous earth, nitrocellulose, polyvinyl alcohol, guar gum, ethyl cellulose, cellulose acetate, polyvinyl pyrrolidone, fluoro rubber (Viton), and function as a binder. And other polymers. In certain embodiments, the initiator composition includes two or more additive materials.

  [0041] In certain embodiments, the additive material is useful in determining certain processing, ignition, and / or combustion characteristics of the initiator composition. In some embodiments, the particle size of the components of the initiator is selected for ignition and burn rate characteristics as is known in the art (see, eg, US Pat. No. 5,739,460).

  [0042] In certain embodiments, it is desirable for the additive to be inert. When sealed within the enclosure, the exothermic redox reaction of the initiator composition results in a pressure increase depending on the components selected. In certain applications, such as in portable medical devices, it is useful to enclose high temperature exothermic materials, products of exothermic reduction reactions, and other chemical reaction products derived from high temperatures in an enclosure. Ensuring exothermic reaction withstands the internal pressure caused by combustion of solid fuel and initiator components, so as to ensure the safety of the heating device and facilitate device manufacture while being realized by properly sealing the enclosure It is useful to minimize the internal pressure. Another means is to minimize the amount of gas phase reaction products produced by the initiator composition during ignition and combustion. Thus, in some embodiments, the pressure in the substrate is managed by minimizing the amount of initiator composition used for solid fuel ignition. Similarly, the pressure is governed by the choice of additive materials that are inert and / or less likely to form large amounts of gas upon ignition.

  [0043] In more preferred embodiments, particularly those in which the heating unit is used in medical applications, the additive has an explosive nature, such as nitrocellulose, as classified by the US Department of Transportation. Desirably not. In a preferred embodiment, the additives are Viton® and Laponite®. These materials bind to other initiator compositions and give the initiator compositions excellent mechanical stability.

  [0044] Ingredients of the initiator composition, including metals, metal-containing oxidants, and / or additive materials, and / or suitable water-soluble or organic-soluble binders, provide useful levels of dispersion and / or uniformity. To achieve, they are mixed by a suitable physical or mechanical method. To simplify handling, use, and / or coating, the initiator composition is prepared as a liquid suspension or slurry in an organic or water-soluble solvent.

  [0045] The ratio of metal reducing agent to metal-containing oxidant is selected to determine the appropriate combustion and spark generation characteristics. In certain embodiments, the initiator composition is formulated to maximize the production of sparks having sufficient energy to ignite the solid fuel. Sparks released from the initiator composition affect the surface of the solid fuel and ignite the solid fuel in a self-supporting exothermic redox reaction. In certain embodiments, the total amount of energy released by the initiator composition varies between 0.25J and 8.5J upon actuation of the composition. These compositions burn with deflagration times between about 5 milliseconds and 30 milliseconds when the composition thickness is about 20 microns to 100 microns. In certain embodiments, the deflagration time of the composition varies from about 5 milliseconds to 20 milliseconds when the composition thickness is about 40-100 microns. In other embodiments, the deflagration time is in the range of about 5-10 milliseconds when the composition thickness is about 40-80 microns.

[0046] The energy of the initiator composition is measured by the mass of the starter prepared with a given formulation if the initiator composition reaction proceeds to completion. The correlation between the power and energy generated by the initiator composition depends on the chemical composition of the initiator composition and the physical structure of the composition, such as thickness per mass. One way to measure the power of the initiator composition is to monitor the intensity of light from the generated spark. Luminous intensity is a function of the number density of the spark, the temperature of the spark, and the chemical and physical properties of the spark. Since the characteristics of the spark are determined by the chemical composition of the initiator, it is assumed that the power correlates with the increase in number and temperature associated with the spark. Example 3 describes the method used to measure light intensity. This method is illustrated in FIG. As shown in FIG. 2, the initiator composition 601 coated on the igniter 600 was activated using two A76 batteries 3.13V (not shown). During operation, the spark 602 was emitted and the photodetector 603 was used to measure the light intensity. Intensity versus time is recorded using an oscilloscope. The voltage output signal from the photodetector 603 is proportional to the luminous intensity at a predetermined wavelength. The starter energy is
Since energy = power × time, it is further measured by integrating the area under the curve. One skilled in the art can determine the appropriate amount of each component based on the stoichiometry of the chemical reaction, known limitations of the desired energy, and / or by routine experimentation. The power is sufficient to ignite the solid fuel, but if the solid fuel is coated as a thin layer on the surface, it is optimized to provide energy that is not strong enough to destroy the solid fuel surface. ing.

[0047] FIGS. 3A and 3B are measurements of strength versus time for two initiator compositions. Intensity was measured by recording the voltage from the photodetector. Figure 3A comprises a nitrocellulose binder on a nichrome wire having a thickness of 0.0008 inches, Nano 0.4 [mu] L Zr: Nano _MoO 3 and (50:50), 1 [mu] L of nano Zr: Nano _MoO 3 (50:50 ) Shows the results. The deflagration time is about 15 milliseconds. FIG. 3B shows 26.5% Al, 51.5% MoO ₃ , 7.8% B, 14.2 on a 0.0008 inch thick nichrome wire (in dry weight percent). Shown are the results with a 1.9 μL mixture of% Viton A500. The deflagration time is about 10 milliseconds.

  [0048] In certain embodiments, such as embodiments in which the solid fuel is coated on a substrate, the uniform or nearly uniform thickness of the solid fuel coating may be altered during the impact of the spark from the initiator composition. It is desirable that the thickness of the thin layer of the solid fuel and the composition of the solid fuel are the maximum temperature produced by the combustion of the solid fuel and the spatio-temporal behavior of the temperature profile. This is because the physical properties can be determined. Studies using thin solid fuel layers with thicknesses that vary from 0.001 inch to 0.005 inch have shown that the maximum temperature reached by the substrate on which the solid fuel is disposed depends on the layer thickness and the composition of the fuel components. It became clear that it depends on. Thus, maintaining the uniformity of the solid fuel layer is necessary to achieve temperature uniformity throughout the region where the solid fuel is disposed on the substrate. In certain applications, for example, uniform heating of the substrate can facilitate the production of aerosols containing high purity drugs or pharmaceutical compositions and maximize aerosol production from drugs deposited during substrate molding. is there. The composition of the present invention is such that it prevents or minimizes damage from sparks that impact the fuel coating. The initiator composition of the present invention is for igniting solid fuel from a distance of about 0.05 to 1.5 inches without destroying the surface area so as to affect the temperature uniformity of the surface area. To generate enough power. In certain embodiments, the initiator composition can be placed directly on the fuel composition itself without affecting the temperature uniformity of the surface area during fuel ignition.

[0049] An example initiator composition of the present invention is a composition comprising, by dry weight percent, 10% Zr, 22.5% B, and 67.5% KClO ₃ , 49. )% Zr, 49.0% MoO ₃ and 2.0% nitrocellulose composition, 33.9% Al, 55.4% MoO ₃ and 8.9% A composition comprising B and 1.8 nitrocellulose, a composition comprising 26.5% Al, 51.5% MoO ₃ , 7.8% B, and 14.2% Viton. And a composition comprising 47.6% Zr, 47.6% MoO ₃ and 4.8% Laponite.

  [0050] The particularly high sparking and low gas production initiator composition of the present invention comprises a mixture of aluminum, molybdenum trioxide, boron, and Viton. In some embodiments, these components are mixed in a mixture based on a dry weight of 20-30% aluminum, 40-55% molybdenum trioxide, 6-15% boron, and 5-20% Viton. The In certain embodiments, the composition comprises 26-27% aluminum, 51-52% molybdenum trioxide, 7-8% boron, and 14-15% Viton. In a more preferred embodiment, aluminum, boron, and molybdenum trioxide constitute nano-sized particles. In other embodiments, Viton is a Viton A500.

  [0051] Examples 1 and 2 describe representative examples of the preparation of initiator compositions of the present invention.

  [0052] The initiator composition is placed directly on the fuel itself and ignited by various means including, for example, optical or impact. Alternatively, the initiator composition is applied to the igniter as shown in FIG. The igniter is physically small, includes a heating element that is thermally insulated and attached to a support.

  [0053] Enough energy is applied to the initiator composition and / or the support on which the initiator composition is disposed to heat the initiator composition to a pyrophoric temperature. In certain embodiments, the ignition temperature of the initiator composition varies from 200 ° C to 500 ° C. The energy source may be any of resistance heating, radiant heating, induction heating, light heating, and impact heating. In certain embodiments, these initiator compositions are operated using low voltage where possible for cost reasons when a small device containing a heating unit and actuation system is desired. For example, such considerations are particularly useful in certain applications involving battery powered portable medical devices. In certain embodiments, the energy source is usefully one or more small low cost batteries such as, for example, a 1.5V alkaline battery or an LR44 battery.

Ignition device
[0054] In another aspect of the invention, a new igniter comprising an electrically resistive material is disclosed. These ignition devices generate jets concentrated in both directions by appropriately installing an electric resistance element on a support having a hole inside. This allows the power dissipated from the igniter by the spark to be simultaneously directed to the plane of the sealed heating unit coated with two solid fuels, thereby igniting both surfaces.

  [0055] In one embodiment, the igniter includes a support including a hole therein, at least two conductors in contact with the support, a resistance heating element at least partially across the hole and attached to the conductor, and a resistance And an initiator composition disposed on at least a portion of each side of the heating element and covering the pores.

  [0056] Electrically resistive materials, also referred to herein as resistive heating elements, include materials that are capable of generating heat when current is supplied. The electrical resistance heating element comprises a material that maintains its integrity at the autoignition temperature of the igniter composition.

  [0057] In some embodiments, the heating element comprises an elemental metal such as tungsten, an alloy such as nichrome, or other material such as carbon. Suitable materials for resistance heating elements are known in the art.

式中、ｘは電気抵抗加熱素子を示す。 [0058] In order to ensure reliable and consistent ignition, the ignition delay time needs to be short and reproducible. The ignition time delay is a function of the rate of temperature rise of the electrical resistance heating element and the ignition temperature of the starter fuel material, as shown by the following equation:

In the formula, x represents an electric resistance heating element.

式中、Ｘは電気抵抗加熱素子を示し、Ｉはブリッジワイヤの中を通る電流であり、Ａ_ｃはブリッジワイヤの断面積であり、ρ_Ｅは電気抵抗であり、ρは密度であり、ｃは比熱である。 [0059] Thus, the faster the electrical resistance heating element is heated, the faster the ignition device ignites. Assuming that the electrical resistance heating element heats adiabatically, the heating rate of the electrical resistance heating element is calculated thermodynamically as follows.

Wherein, X represents an electrical resistance heating element, I is the current through the inside of the bridge wire, A _c is the cross-sectional area of the bridge wire, [rho _E is an electrical resistance, [rho is the density, c Is the specific heat.

[0060] If the current is limited, such as when a battery is used to ignite the igniter, the higher ρ _E / (ρc) and the smaller the cross-sectional area, the higher the heating rate. Thus, in one embodiment, an electrical resistance heating element having a large ρ _E / (ρc) is used. In one embodiment, nichrome is used because nichrome has a large ρ _E / (ρc) of 3.92 × 10 ⁻¹³ Ωm ⁴ K / J, as well as a high melting point of 1672 ° K.

  [0061] In some embodiments, it is further preferred that the electrical resistance heating element is simultaneously chemically inert or corrosion resistant and easily soldered or welded to form an electrical connection.

  [0062] The resistive heating element has a suitable shape. For example, the resistance heating element is in the form of a wire, filament, ribbon, or foil. However, the size of the resistance heating element affects the ignition. The selection of the dimensions of the resistance heating element depends on the system to which the resistance heating element is applied. In one embodiment, the resistive heating element is a wire having a diameter of less than about 0.001 inch, in another embodiment less than about 0.0008 inch, and in yet another embodiment about 0.0006. Less than an inch.

  [0063] The appropriate selection of the resistance of the heating element is determined at least in part by the current of the current source, the desired autoignition temperature, or the desired ignition time. If a battery is used, the resistance of the electrical resistance heating element should be the same as the internal resistance of the battery in order to supply maximum power to the electrical resistance heating element. Thus, two batteries, such as LR44 or equivalent, are used to operate the igniter, and each battery supplies about 1.5V with an internal resistance of 2 ohms and a maximum current of 0.5 amps each. In form, the electrical resistance heating element resistance should be about 4 ohms as well. In some embodiments, the electrical resistance of the heating element varies from 2Ω to 4Ω.

  [0064] Once the wire diameter is determined, the length of the wire is automatically fixed by a predetermined resistance of the resistive heating element. Thus, for example, if the electrical resistance heating element is Nichrome with a 0.0008 inch diameter powered by two 1.5V LR44 button batteries, the length of the wire will be the internal resistance of the battery used. It should be about 0.030 inches to produce a resistance of close to about 3 ohms.

  [0065] The electrical resistance heating element is connected to an electrical conductor. The heating element is soldered or electrically connected to a conductor such as a Cu conductor or graphite / silver ink trace disposed on the support. The support may be an electrically insulating substrate such as polyimide, polyester, or fluoropolymer. The conductor is disposed between two opposing layers of electrically insulating material, such as a flexible or rigid printed circuit board material. In certain embodiments, the support is thermally isolated to minimize the possibility of heat loss. In this way, the dissipation of thermal energy applied to the assembly and support combination is minimized, thereby reducing the power requirements of the energy source, being physically small and less expensive. Facilitating the use of an improved heat source.

  [0066] The support houses a hole or opening therein. The resistive heating element is at least partially disposed over the hole. Since the igniter has only one resistance heating device, in order to generate a squirt or spark in both directions, a spark must be generated from the other side of the support attached to the side where the resistance heating element is attached. A hole is necessary to enable this. This allows ignition of fixed fuel in contact with sparks coming from both sides of the igniter. In some embodiments, the diameter of the hole in the support is determined by the length of the resistive heating element.

  [0067] An initiator composition as disclosed herein is such that when the electrically resistive material is heated to the ignition temperature of the initiator composition, the initiator composition ignites to produce a spark. And disposed on the surface of the electrical resistance material. The initiator composition is applied to the electrical resistance heating element by depositing and drying a slurry containing the initiator composition. In certain embodiments, the autoignition temperature of the initiator composition varies from 200 ° C to 500 ° C.

  [0068] The resistance heating element is electrically connected and suspended between two electrodes that are electrically connected to a power source. If the power source is a battery, a capacitor is added to increase the ignition reliability of the system. The capacitor discharges the energy stored in the capacitor, thereby facilitating the supply of additional energy to the electrical resistance element in the initial stage of heating, shortening the ignition delay and reducing misfire. In certain embodiments where the igniter is used in a heating unit that is resistively actuated, a capacitor is added to the power system.

  [0069] In some embodiments, the sign of deflagration appears in less than 20 milliseconds after activation of the igniter, in another embodiment, the sign of deflagration appears in less than 10 milliseconds, and in yet another embodiment, The sign appeared in less than 6 milliseconds, and in yet another embodiment, the sign of deflagration appeared within 1 millisecond after activation of the igniter.

  [0070] An embodiment of the ignition device of the present invention including a resistive heating element is shown in FIG. As shown in FIG. 1, resistance heating element 716 is electrically connected to electrode 714. The electrode 714 is electrically connected to an external power source such as a battery (not shown). As shown in FIG. 1, the electrode 714 is disposed in a laminate material, such as a printed circuit material. Such materials and methods for making such flexible or rigid laminated circuits are well known in the art. In some embodiments, the laminate material 712 does not degrade at the temperature reached by the resistive heating element 716 due to an exothermic reaction, including the spark generated by the initiator composition 718, and at the temperature reached during combustion of the solid fuel. Contains materials. For example, the laminate 712 includes Kapton®, fluorine laminate material or FR4 epoxy / fiber glass printed circuit board. The resistive heating element 716 is disposed in the opening 713 in the laminate 712. Opening 713 thermally insulates resistive heating element 716 to minimize heat dissipation and facilitate the transfer of heat generated by the resistive heating element to the initiator composition and is released from initiator composition 718. Provide a path for sparks that affect solid fuel (not shown).

  [0071] As shown in FIG. 1, the initiator composition 718 is disposed on a resistive heating element 716.

  [0072] The following procedure was used to apply an initiator composition to a resistive heating element.

  [0073] A 0.0008 inch diameter nichrome wire was soldered to a Cu conductor placed on a 0.005 inch thick FR4 epoxy / fiberglass printed circuit board (Onanon). The dimensions of the igniter circuit board were 1.82 inches x 0.25 inches. Conductor leads extend from the printed circuit board to the power source for connection. In certain embodiments, the electrical lead is connected to an electrical connector.

  [0074] The igniter printed circuit board was sonicated (Branson 8510R-MT) in DI water for 10 minutes, cleaned, dried, sprayed with acetone, and air dried.

[0075] initiator composition is 0.68 grams of nano-aluminum (40 to 70 nm diameter; Argonaide Nanomaterial Technologies, Sanford, FL ) and, 1.32 g nano _MoO 3 in (EM-NTO-U2; Climax Molybdenum, Henderson, CO) and 0.2 grams of nanoboron (33, 2445-25G; Aldrich). A slurry containing the initiator composition was prepared by adding 8.6 mL of 4.25% Viton A500 (4.25 grams Viton in 100 mL Mallinckrodt) solution.

  [0076] A 1.1 μL drop of slurry was deposited on the heating element, dried for 20 minutes, and another 0.8 μL drop of slurry containing the initiator composition was deposited on the opposite side of the heating element.

[0077] Al: MoO ₃ : B initiator in 1-50 milliseconds, typically in 1-6 milliseconds, when 3.0V is applied to the nichrome heating element through a 1000 μF capacitor from an A76 alkaline battery The composition was ignited. For example, a surface of a solid fuel comprising a metal reducing agent and a metal-containing oxidant, such as a fuel comprising 76.16% Zr: 19.04% MoO ₃ : 4.8% Laponite® RDS, is reduced to 0. When installed within 12 square inches, the spark produced by the initiator composition ignited the solid fuel to produce a self-supporting exothermic reaction. In some embodiments, a 1 μL drop of slurry containing the initiator composition is deposited on the surface of the solid fuel proximate to the initiator composition disposed in the resistive heating element to facilitate ignition of the solid fuel.

[0078] An initiator composition comprising Al: MoO ₃ : B is attached to a nichrome wire and is subjected to mechanical and environmental tests including temperature cycling (−25 ° C. ← → 40 ° C.), drop test, and impact test. Later, physical integrity was maintained. Examples 3-5 further illustrate some tests performed on the igniter.

  [0079] The ignition device disclosed herein and / or the initiator composition disclosed herein is used to ignite solid fuel in a heating unit. They have particular application in sealed heating units such as, for example, heating units described below.

Heating unit and igniter comprising initiator composition
[0080] An embodiment of a heating unit in which the initiator composition of the present invention is used is shown in FIG. 4A. The heating unit 10 includes a substrate 12 formed from a thermally conductive material. Thermally conductive materials are well known and typically include, but are not limited to, metals such as aluminum, iron, copper, stainless steel, alloys, ceramics, and filled polymers. The substrate is formed from one or more such materials, and in certain embodiments has a multilayer structure. For example, the substrate includes one or more films and / or coatings and / or multiple sheets or layers of material. In some embodiments, a portion of the substrate is formed from a plurality of sections. In some embodiments, the plurality of sections forming the substrate of the heating unit have different thermal characteristics. The substrate can be any suitable shape, and the rectangular structure shown in FIG. 4A is merely exemplary. The substrate further has an appropriate thickness, and the thickness of the substrate may vary in certain areas. The substrate 12 as shown in FIGS. 4A and 4B has an inner surface 14 and an outer surface 16. Heat is conducted from the inner surface 14 to the outer surface 16. An object or object placed in close proximity to or in contact with the outer surface 16 achieves a desired action, such as warming or heating a solid or liquid object, inducing further reactions, or inducing a phase change. For receiving the transmitted heat. In some embodiments, the heat of conduction induces a phase change in the compound that is in direct or indirect contact with the outer surface 16.

  [0081] The heating unit 10 further includes a solid fuel 20 on one side. The solid fuel 20 may be proximate to the inner surface 14, where the term “proximity” refers to indirect contact as distinguished from “adjacent” which refers to direct contact. As shown in FIG. 4A, the solid fuel 20 may be proximate to the inner surface 14 through an intervening open space defined by the inner surface 14 and the solid fuel 20. In some embodiments, as shown in FIG. 4B, the solid fuel 20 is in direct contact with or adjacent to the inner surface 14.

  [0082] In some embodiments, the solid fuel includes a metal reducing agent and an oxidizing agent, such as, for example, a metal-containing oxidizing agent.

  [0083] In some embodiments, the metal reducing agent is molybdenum, magnesium, calcium, strontium, barium, boron, titanium, zirconium, vanadium, niobium, tantalum, chromium, tungsten, manganese, iron, cobalt, nickel, copper, zinc. Including, but not limited to, cadmium, tin, antimony, bismuth, aluminum, and silicon. In some embodiments, the metal reducing agent includes aluminum, zirconium, and titanium. In some embodiments, the metal reducing agent includes two or more metal reducing agents.

[0084] In certain embodiments, the oxidant comprises oxygen, an oxygen-based gas, and / or a solid oxidant. In certain embodiments, the oxidant includes a metal-containing oxidant. In some embodiments, the metal-containing oxidant includes, but is not limited to, perchlorate and transition metal oxide. Examples of perchlorates include potassium perchlorate (KClO ₄ ), potassium chlorate (KClO ₃ ), lithium perchlorate (LiClO ₄ ), sodium perchlorate (NaClO ₄ ), and magnesium perchlorate [ Including alkali metal or alkaline earth metal perchlorates such as, but not limited to, Mg (ClO ₄ ) ₂ ]. In some embodiments, the transition metal oxide that functions as an oxidant is an oxide of molybdenum (eg, MoO ₃ ), an oxide of iron (eg, Fe ₂ O ₃ ), an oxide of vanadium (V ₂ O ₅ ). , Chromium oxide (CrO ₃ , Cr ₂ O ₃ ), manganese oxide (MnO ₂ ), cobalt oxide (Co ₃ O ₄ ), silver oxide (Ag ₂ O), copper oxide ( CuO), tungsten oxide (WO ₃ ), magnesium oxide (MgO), and niobium oxide (Nb ₂ O ₅ ), but are not limited thereto. In some embodiments, the metal-containing oxidant includes two or more metal-containing oxidants.

[0085] In some embodiments, the metal reducing agent that forms the solid fuel is selected from zirconium and aluminum, and the metal-containing oxidant is selected from MoO ₃ and Fe ₂ O ₃ .

[0086] The ratio of metal reducing agent to metal-containing oxidant is selected to determine the ignition temperature and combustion characteristics of the solid fuel. A typical chemical fuel contains 75% zirconium and 25% MoO ₃ by weight percentage. In certain embodiments, the amount of metal reducing agent varies from 60% to 90% by weight of the total dry weight of the solid fuel. In certain working liquids, the amount of metal-containing oxidant varies from 10% to 40% by weight of the total dry weight of the solid fuel.

[0087] In certain embodiments, the solid fuel includes additive materials, for example, to facilitate processing during and after ignition of the solid fuel and / or to determine the thermal and temporal characteristics of the heating unit. The additive may be organic or inorganic and functions as a binder, an adhesive, a gelling agent, a thixotropic agent, and / or a surfactant. Examples of gelling agents include clays such as Laponite (R), montmorillonite, Cloisite (R), n is 3 or 4, M is Ti, Zr, Al, B or other materials And includes, but is not limited to, metal alkoxides as represented by the chemical formulas R—Si (OR) _n and M (OR) _n and colloidal particles based on transition metal hydroxides or oxides. Examples of binding agents include soluble silicates such as sodium silicate or potassium silicate, aluminum silicates, metal alkoxides, inorganic polyanions, inorganic polycations, and sols based on alumina or silica. Inorganic sol / gel materials are included, but not limited thereto.

  [0088] Other useful additive materials include glass beads, diatomaceous earth, nitrocellulose, polyvinyl alcohol, and other polymers that function as binders. In some embodiments, the solid fuel includes two or more additives. Solid fuel components including metals, oxidants, and / or additive materials, and / or other suitable water-soluble or organic soluble binders are suitable for achieving a useful level of dispersion or uniformity. Mixed by physical or mechanical methods. In certain embodiments, the solid fuel is degassed.

  [0089] The solid fuel in the heating unit is of an appropriate shape and has an appropriate size. For example, as shown in FIG. 4A, the solid fuel 20 is shaped for insertion into a square or rectangular heating unit. As shown in FIG. 4B, the solid fuel 20 includes a surface 26 and side surfaces 28, 30. FIG. 4C shows an embodiment of the heating unit. As shown in FIG. 4C, the heating unit 40 includes a substrate 42 having an outer surface 44 and an inner surface 46. In one embodiment, the solid fuel 48 in the form of a rod that extends the length of the substrate 42 fills the internal volume defined by the inner surface 46. In certain embodiments, the internal volume defined by the inner surface 46 is arranged such that the solid fuel 48 is arranged as a cylinder adjacent to the inner surface 46 and / or as a rod that exhibits a diameter that is smaller than the diameter of the inner surface 46. As such, it includes intervening spaces or layers. It is understood that the finned or ribbed outer surface provides a large surface area that serves to facilitate heat transfer from the solid fuel to the material or composition in contact with the surface.

  [0090] In certain embodiments, the solid fuel is disposed on the substrate as a membrane or thin layer, wherein the thickness of the thin layer of solid fuel varies, for example, from 0.001 inch to 0.030 inch. The initiator composition is placed directly on the fuel itself and added by various means such as, for example, optical or impact. As shown in FIG. 4A, the heating unit 10 includes an initiator composition 50 that ignites a portion of the solid fuel 20. In some implementation liquids, the initiator composition 50 is placed near the central region 54 of the solid fuel 20, as shown in FIGS. 4A and 4B. Initiator composition 50 may be placed, for example, in other areas of the solid fuel toward the edge. In certain embodiments, the heating unit includes two or more initiator compositions, and the two or more initiator compositions 50 are located on the same side as the solid fuel 20 or on different sides. In certain embodiments, the initiator composition 50 is attached to a support member 56 that is integrally formed with the substrate 12 and / or secured within an appropriately sized opening in the substrate 12. The support member 56 and the substrate 12 are sealed to prevent reactants and reaction products from being released outside the heating unit 10 during ignition and combustion of the solid fuel 20. In some embodiments, electrical leads 58a, 58b in contact with the initiator composition 50 extend from the support member 56 for electrical connection to a mechanism (not shown) configured to operate the initiator composition 50. .

  [0091] Alternatively, the initiator composition is placed directly on the fuel itself and ignited by a variety of means including, for example, optical or impact.

  [0092] FIG. 5A shows a longitudinal cross-sectional view of another embodiment of a heating unit incorporating the initiator composition of the present invention. As shown in FIG. 5A, the heating unit 60 includes a substrate 62 that is substantially cylindrical in shape and terminates at one end of a tapered tip portion 64 and terminates at the other end of the open container 66. The substrate 62 has an inner surface 68 and an outer surface 70 that each define an inner region 72. The inner backing member 74 may be cylindrical in shape and positioned within the inner region 72. The opposite ends 76, 78 of the backing member 74 may be open. In certain embodiments, the backing member 74 includes thermodynamic and thermally conductive materials or heat absorbing materials, depending on the desired thermal and temporal dynamics of the heating unit. When made of a heat absorbing material, the backing member 74 lowers the maximum temperature reached by the substrate 62 after ignition of the solid fuel 80.

  [0093] In certain embodiments, a solid fuel 80 comprising, for example, any of the solid fuels described herein is confined between the substrate 62 and the backing member 74 and fills the interior region 72. The solid fuel 80 is adjacent to the inner surface 68 of the substrate 62.

  [0094] In some embodiments, an initiator composition 82 as described herein is placed in an open container 66 of the substrate 62 and configured to ignite the solid fuel 80. In certain embodiments, the support member 84 is positioned in the open container 66 and secured in place using a suitable mechanism such as, for example, bonding or welding. Support member 84 and substrate 62 are sealed to prevent release of reactants or reaction products produced during ignition and combustion of initiator composition 82 and solid fuel 80. The support member 84 includes a recess 86 in the internal region 72 that faces the surface. The recess 86 holds the initiator composition 82. In some embodiments, electrical stimulation is applied directly to the initiator composition 82 via leads 88, 90 connected to the positive and negative terminals of a power source such as a battery (not shown). The leads 88, 90 are connected to an electrical resistance heating element that is placed in physical contact with the initiator composition 82 (not shown). In certain embodiments, the leads 88, 90 are coated with an initiator composition 82.

  [0095] Referring to FIG. 5A, the application of a stimulus to the initiator composition 82 results in the creation of a spark directed from the open end 78 to the end 76 of the backing member 74. The spark directed toward end 76 contacts solid fuel 80 and causes solid fuel 80 to ignite. The ignition of the solid fuel 80 generates a self-propagating wave of the ignited solid fuel 80, which propagates from one end 78 to the tip 64 and toward the support member 84 held at the container end 66 of the substrate 62. Return. The self-propagating wave of the ignited solid fuel 80 generates heat conducted from the inner surface 68 to the outer surface 70 of the substrate 62.

  [0096] An embodiment of a heating unit using the initiator composition of the present invention and having a different initial setup is shown in FIG. 5B. As shown in FIG. 5B, the heating unit 60 includes a first initiator composition 82 disposed in the recess 86 in the support member 84 and a second initiator disposed at the open end 76 of the backing member 74. An initiator composition 94. A backing member 74 located in the inner region 72 defines an open region 96. The solid fuel 80 is disposed in an internal region between the substrate 62 and the backing member 74. In certain embodiments, sparks generated during the application of electrical stimulation to the first initiator composition 82 via the leads 88, 90 pass through the open region 96 to the second initiator composition 94. To ignite the second initiator composition 94 and generate a spark. The spark generated by the second initiator composition 94 then ignites the solid fuel 80, and the ignition first occurs toward the tip of the substrate 62 and is transmitted to the opposite end by a self-propagating wave of ignition.

[0097] In certain embodiments, the heating unit comprising and described the initiator composition of the present invention and illustrated in FIGS. 4A-4C and 5A-5C is used in applications where rapid heating is useful. As an example, a heating unit substantially as shown in FIG. 5B was manufactured using the initiator composition of the present invention to access solid fuel ignition. Referring to FIG. 5B, the cylindrical substrate 62 was approximately 1.5 inches long and the diameter of the open container 66 was 0.6 inches. A solid fuel 80 containing 75% by weight Zr: 25% MoO ₃ was placed in an internal region in the space between the backing member 74 and the inner surface of the substrate 62. 5 mg of a first initiator composition 82 containing 10% by weight Zr: 22.5% B: 67.5% KClO ₃ was placed in the recess of the support member and 10% Zr by weight percent. 10 mg of second initiator composition 94 containing: 22.5% B: 67.5% KClO ₃ was placed on the open end 76 of the backing member 74 near the taper of the heating unit 60. The electrical leads 88, 90 from the two 1.5V batteries ignite the first initiator composition 82 and thus generate a spark to ignite the second initiator composition 94, A current of 0.3 amperes was supplied. Both initiators were ignited in the range of 1-20 milliseconds after the current supply. The spark produced by the second initiator composition 94 ignited the solid fuel 80 in the cylindrical tapered tip 64 and the outer substrate surface reached a maximum temperature of 400 ° C. in less than 100 milliseconds.

  [0098] When sealed within an enclosure, the exothermic redox reaction of the fuel and / or initiator composition results in a significant increase in pressure. In some embodiments, the internal pressure of the heating unit is managed or reduced by creating substrates, backings, and other internal components from materials that produce minimal gas products at high temperatures. In certain embodiments, the pressure is managed or reduced by providing an internal volume where gas is collected and / or exhausted as the initiator and solid fuel are combusted. In certain embodiments, the internal volume comprises a porous or fibrous material having a large surface area and a large interstitial volume. In certain embodiments, the immediate explosion of pressure resulting from solid fuel combustion is reduced by installing shock absorbing material and / or coating in a heating unit. Shock absorbing materials are described in the literature and in US patent applications filed on May 20, 2004 and entitled “Self Contained Heating Unit and Drug Supply Unit Employing The Same”. An embodiment of a heating unit comprising a shock absorbing material is shown schematically in FIGS. 6A-6B and FIGS. 7A-7B.

  [0099] For example, an embodiment of a heating unit using the ignition device of the present invention as shown in FIG. 1 and the initiator composition of the present invention is shown in FIGS. FIG. 6A is a perspective view, and FIG. 6B is an assembly view of the heating unit 500. As shown in FIG. 6A, the heating unit 530 includes first and second substrates 510 and spacers 518.

  [00100] The first and second substrates 510 include regions with solid fuel 512 disposed on the inner surface. The first and second substrates 510 include a thermally conductive material, such as, for example, metals, ceramics, and thermally conductive polymers, as described herein. In some embodiments, the substrate 510 includes, but is not limited to, metals such as stainless steel, copper, aluminum, nickel, or alloys thereof. The thickness of the substrate 510 may be thin to facilitate heat transfer from the inner surface to the outer surface and / or to minimize the thermal mass of the device. In some embodiments, the thin substrate promotes rapid and uniform heating of the outer surface using a lower amount of solid fuel than the thick substrate. The substrate 510 further provides structural support for the solid fuel 512. In some embodiments, substrate 510 includes a metal foil. In some embodiments, the thickness of the substrate 510 varies from 0.001 inches to 0.020 inches, in some embodiments, from 0.001 inches to 0.010 inches, and in some embodiments, 0.002 inches. It varies from inches to 0.006 inches, and in one embodiment, varies from 0.002 inches to 0.005. The use of a smaller amount of solid fuel facilitates control of the heating process as well as facilitates miniaturization of the drug delivery unit.

  [00101] In some embodiments, the thickness of the substrate 510 varies across the surface. For example, the variable thickness can be used to control the temporal and spatial characteristics of heat transfer and / or the edge of the substrate 510, for example, the spacer 518, the opposing substrate 510, or another support (not shown). Useful for sealing). In some embodiments, the substrate 510 has a uniform or nearly uniform thickness in the region of the substrate where the solid fuel 512 is disposed to facilitate achieving a uniform temperature throughout the region of the substrate where the solid fuel 512 is disposed. It shows.

  [00102] Substrate 510 includes a region of solid fuel 512 disposed on the inner surface, eg, an opposite substrate 510 opposite the surface. Solid fuel 512 is applied to substrate 510 using any suitable method. For example, the solid fuel 512 is applied to the substrate 510 by brushing, dip coating, screen printing, roller coating, spray coating, ink jet printing, stamping, spin coating, or the like. The solid fuel 512 may be applied to a portion of the substrate 510 as a thin film or layer. The thickness of the thin layer of the solid fuel 512, the composition of the solid fuel 512, determines the maximum temperature produced by the combustion of the solid fuel, as well as the temporal and spatial dynamics of the temperature profile.

[00103] In certain embodiments, solid fuel _{512, Zr / MoO 3, Zr /} Fe 2 O 3, Al / MoO 3, or comprises a mixture of Al / _Fe 2 _{O 3.} In some embodiments, the amount of metal reducing agent varies from 60% to 90% by weight and the amount of metal-containing oxidizing agent varies from 40% to 10% by weight.

  [00104] As shown in FIGS. 6A-6B, the heating unit includes an ignition assembly or igniter 520. In some embodiments, the igniter 520 is heated and disposed on an electrical resistance heating element connected to an electrical lead disposed between two strips of insulating material (not shown), Initiator composition 522 that is capable of producing a spark. The heating element on which the initiator composition is disposed is exposed through an opening at the end of the ignition assembly 520. The electrical leads are connected to a power source (not shown).

  [00105] Initiator composition 522 comprises any of the initiator compositions or compositions described herein.

  [00106] The igniter 520 is positioned with respect to the solid fuel 512 such that the spark generated by the initiator composition 522 is directed to the solid fuel region 512 and induces ignition and combustion of the solid fuel 512. Initiator composition 522 may be placed anywhere as long as the spark generated by the initiator can induce ignition of solid fuel 512. The position of the initiator composition 522 with respect to the solid fuel 512 determines the direction in which the solid fuel 512 burns. The igniter 520 is preferably arranged such that the jet generated from the igniter is directed to the surface of the solid fuel and both the fuel coated substrates ignite.

  [00107] In certain embodiments, the heating unit 500 comprises two or more igniters 520 and / or each igniter 520 includes two or more initiator compositions 522.

  [00108] As shown in FIG. 6A, the heating unit 500 includes a spacer 518. The spacer 518 holds the ignition device 520. In some embodiments, the spacer 518 provides a volume or space within the thin film heating unit 500 for collecting gases and by-products generated during the combustion of the solid fuel 512. The volume created by the spacer 518 reduces the internal pressure within the heating unit 500 during fuel ignition. In certain embodiments, the volume includes a porous or fibrous material, such as ceramic, or a fiber mat that is a small portion of the volume that is not filled with a solid matrix component. The porous or fibrous material provides a large area where the reaction product generated during combustion of the initiator composition and solid fuel is absorbed, adsorbed or reacted. The pressure generated during combustion depends in part on the initiator composition used and the composition and amount of solid fuel. In some embodiments, the spacer is less than 0.3 inches thick, and in some embodiments, less than 0.2 inches thick. In some embodiments, the maximum internal pressure during and after combustion is less than 50 psig, in some embodiments less than 20 psig, in some embodiments less than 10 psig, and in other embodiments less than 6 psig. In some embodiments, the spacer may be a material that can maintain structural and chemical properties at temperatures generated by solid fuel combustion. In some embodiments, the spacer is a material capable of maintaining structural and chemical properties up to a temperature of about 100 ° C. The material forming the spacer does not produce and / or release gases and / or reaction products at the temperature given to the material by the heating unit, or only a minimal amount of gas and / or reaction products. Convenient to produce. In some embodiments, the spacer 518 may optionally include a filler, such as a metal, such as polyimide, fluoropolymer, polyetherimide, polyetherketone, polyethersulfone, polycarbonate, and other resistance. Includes thermoplastic materials such as, but not limited to, high temperature thermoplastic polymers, or thermosetting materials.

  [00109] In some embodiments, the spacer 518 provides a thermal insulator such that the spacer does not contribute to the thermal mass of the thin film drug delivery unit, thereby facilitating heat transfer to the substrate on which the drug 514 is disposed. Including. Thermal insulators or shock absorbing materials such as glass, silica, ceramic, carbon, or high temperature polymer fiber mats are used. In some embodiments, the spacer 518 may be a thermal conductor so that the spacer functions as a heat shunt to control the temperature of the substrate.

  [00110] The substrate 510, spacer 518, and igniter 520 are sealed. The seal holds the reactants and reaction products released by the combustion of the solid fuel 514 and provides a self-contained unit. As shown in FIG. 6A, the substrate 510 is sealed to the spacer 518 using an adhesive 516. The adhesive 516 may be a heat sensitive film capable of bonding the substrate 510 and the spacer 518 when heat and pressure are applied. In some embodiments, the substrate 510 and the spacer 518 are bonded using an adhesive applied to at least one of the surfaces to be bonded, the components to be assembled, and the curing adhesive. The passage in the space 518 where the igniter 520 is inserted is also sealed using an adhesive. In certain embodiments, other methods of forming a seal are used, such as, for example, welding, soldering, or clamping.

  [00111] In some embodiments, the elements forming the heating unit 500 are assembled and sealed using thermoplastic or thermoset molding methods such as insert molding and transfer molding.

  [00112] A suitable sealing method is determined at least in part by the material forming the substrate 518 and the material forming the spacer 518. In certain embodiments, the heating unit 500 is sealed to withstand a maximum pressure of less than 50 psig. In some embodiments, less than 20 psig, and in some embodiments, less than 10 psig.

  [00113] Example 8 describes the preparation of a heating unit comprising a thermal resistance igniter of the present invention coated with an initiator composition of the present invention.

  [00114] In another embodiment of a heating unit comprising the initiator composition of the present invention, an optical ignition system is used to ignite the heating unit as well. Optical ignition requires the use of either a light sensitive material or initiator composition, a light source for actuation of the light sensitive material or initiator composition, or an ultra-high intensity light source, eg, a laser.

  [00115] Various initiator compositions as described above are used. In some embodiments, for example, metals such as aluminum, zirconium, and titanium and oxidizing agents such as potassium chlorate, rim perchloric oxide, copper oxide, tungsten trioxide, and molybdenum trioxide are used. The Typically, the one or more initiator composition materials are light absorbing or coated with a light absorbing chemical. For example, metals and oxidants containing initiator compositions that are sensitive to a particular wavelength or wavelength range, such as compositions that are highly absorbing in the ultraviolet region of the electromagnetic spectrum, are used as well. By changing the ratio of solid materials in the initiator composition, it is possible to increase or decrease the energy emitted by the final initiator composition and increase or decrease the sensitivity to light pulses, if necessary.

  [00116] The initiator composition is applied directly to the fuel on the substrate, igniter, as disclosed herein, or transparent light that directs light to the initiator composition or material. As long as there is a window, it is installed somewhere in the heating unit and during operation the initiator composition ignites the fuel in the heating unit. In certain embodiments, the initiator composition is placed in a hole in a glass fiber filter that is positioned proximate to the surface of the coated fuel.

  [00117] Ignition of the fuel in the thermal package is activated by transmitting a light pulse to the initiator composition through a transparent light window. The light window is made of any material that readily transmits a light pulse, such as, for example, glass, acrylic, or polycarbonate. The window is located where light is transmitted to the initiator. In some embodiments, the window forms part of the enclosure of the heating unit. In other embodiments, the window is fully contained within the system. In certain embodiments, the window is part of the light guide assembly. The light guide assembly may also comprise a beam splitter. Light coming from the light source passes through the beam splitter and is directed to two or more initiator compositions located in the heating unit to ignite simultaneously or sequentially two or more fuel coated substrates. . In some cases, an optical fiber is used to ignite a plurality of heating units simultaneously. In other embodiments, the window is covered with a material that causes the wavelength of light emitted by the window to be different from the light received by the window. For example, the illumination light source emits ultraviolet light and the coating is used to emit visible wavelengths in response to the ultraviolet light.

  [00118] Various means of operating optical ignition are used. In some embodiments, conductive means are provided for generating a light pulse when the threshold is achieved. The conductive means may be part of the heating unit itself, for example, housed in a spacer of the heating unit or separated from the heating unit. The conductive means for generating the light pulse includes, for example, a xenon flash lamp, a light emitting diode, and a laser.

  [00119] Multiple embodiments of a heating unit 900 including an optical ignition system are shown in FIGS. As shown, the initiator composition 904 is contained within the hole 908 of the shock absorbing material 903 such that the initiator composition 904 is proximate to the fuel coating. One or more shock absorbing materials 903 are added to the heating unit as long as there is no hindrance by the shock absorbing material that prevents contact between the ignited initiator composition and the solid fuel. A hole or space 908 is cut into the shock absorbing material 903 to provide an opening for such contact. Two or more initiator compositions 904 are installed in a single heating unit 900 to initiate combustion of two or more solid fuel coatings simultaneously, as shown in FIG. 7B. The shock absorbing material is contained in the spacer 902 as shown in FIGS.

  [00120] As shown in FIG. 7A, the light window 901 forms part of the enclosure of the heating unit. In some embodiments, the light window 901 forms part of a wave guide system (not shown) that includes a beam splitter 907, as shown in FIG. 7B. Beam splitter 907 is used to direct one light source to two initiator compositions so as to ignite both solid fuel coated substrates together.

  [00121] Various means are used to seal the heating unit. Sealant 906 may be an adhesive such as double-sided tape or epoxy, or other methods of forming a seal such as, for example, welding, soldering, clamping, or crimping.

  [00122] In an embodiment, the light source (not shown) may be part of a heating unit and is stored in a spacer 902 housed in the heating unit 900. The light source may be powered by a battery (not shown).

  [00123] An example of the preparation of a single heating unit using optical ignition is described in Example 9.

  [00124] Impact igniters are also used to ignite the compositions of the present invention within a heating unit. Impact igniters generally include a deformable igniter tube having an anvil coated with an initiator composition therein. This igniter is actuated by mechanical shock or force.

  [00125] In order for the initiator composition to operate satisfactorily when activated, the material must exhibit proper ignition sensitivity and properly ignite the solid fuel. A variety of initiator compositions as disclosed herein are used. Typically, the initiator composition is prepared as a liquid suspension in an organic or water-soluble solvent to coat the anvil and generally contains a soluble binder to adhere the coating to the anvil.

  [00126] By changing the ratio of solid materials in the initiator composition, the energy released by the final initiator composition may be increased or decreased as necessary to increase or decrease sensitivity to air or oxygen and impact. Is possible.

  [00127] The coating of initiator material is applied to the anvil in a variety of conventional ways. For example, an anvil is immersed in a slurry of the initiator composition, followed by air drying or heating to remove the liquid and produce a solid adhesive coating having the desired properties already described. The Alternatively, the slurry is sprayed or spun on the anvil and then processed to produce a solid coating. The thickness of the coating of the initiator composition on the anvil is such that when the anvil is placed on the ignition tube, the initiator composition is approximately a few thousandths of an inch relative to the inner wall of the ignition tube, for example,. The thickness should be a small distance of 004 inches.

  [00128] The anvil in which the initiator composition is disposed is typically a metal wire or rod. The anvil should be made of a suitable metal composition such as, for example, stainless steel so as to exhibit high temperature resistance and low thermal conductivity. The anvil is disposed within the metal ignition tube and extends substantially coaxially. Therefore, the anvil should be of a diameter slightly smaller than the inner diameter of the ignition tube so that it is separated from the inner wall of the ignition tube by a small distance, for example, about 0.05 inches.

  [00129] The anvil is disposed in a metal ignition tube. The ignition tube should be made of an easily deformable material, for example, a thin wall tube (e.g., 0. 0) made of a suitable metal composition such as aluminum, nickel-chromium-iron alloy, brass, or steel. 003 inch wall thickness). The anvil is held or clamped in place in the ignition tube near its outer end by crimping or other methods typically used.

  [00130] The ignition of the fuel is activated by a forced mechanical impact or blow applied to the side of the metal igniter tube to deform inwardly relative to the coating of initiator material on the anvil, through which the fuel cladding Initiating deflagration of the initiator material into the heated unit. Various means for applying a mechanical shock are used. In some embodiments, a spring-loaded impinger or striker is used to activate the ignition.

  [00131] An embodiment of a heating unit 800 comprising an impact igniter is shown in FIG. As shown in FIG. 8, a deformable ignition tube 805 containing an anvil 803 coated with an initiator composition is installed between two substrates 801 coated with a solid fuel 802. The open end of the ignition tube is arranged in the heating unit 800.

  [00132] An example of the preparation of a heating unit using impact ignition is described in Example 10.

  [00133] Other embodiments will be apparent to those skilled in the art from consideration and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only.

  [00134] In the examples below, the following abbreviations have the following meanings. If an abbreviation is not defined, it has a generally accepted meaning.

  [00135] wt% wt%

  [00136] psig pound per square inch, gauge

  [00137] DI deionization

  [00138] mL milliliter

  [00139] msec msec

  [00140] L / min liter per minute

  [00141] μm micrometer

[Example 1]
Initiator composition embodiment
[0142] The following steps, 23.7% of Zr: 23.7% of _MoO 3: A slurry of the initiator composition comprising 50.2% water: 2.4% Laponite (R) RDS Used to prepare.

  [00143] To prepare wet zirconium (Zr), an as-obtained suspension of Zr in DI water (Chemall, Germany) was stirred on a rotating mixer for 30 minutes. 10-40 mL of wet Zr was dispensed into a 50 mL centrifuge tube and centrifuged at 3200 rpm for 30 minutes (Sorvall 6200RT). DI water was removed to leave wet Zr pellets.

  [00144] To prepare a 15% Laponite® RDS solution, 85 grams of DI water was added to a beaker. During stirring, 15 grams of Laponite® RDS (Southern Clay Products, Gonzalez, TX) was added and the suspension was stirred for 30 minutes.

[00145] The reaction slurry was prepared by first removing the wet Zr pellet as previously prepared from the centrifuge tube and placing it in a beaker. After weighing the wet Zr pellets, the weight of the dry Zr is:
Dry Zr (g) = 0.8234 (wet Zr (g)) − 0.1059
Determined from. The dry weight of Zr was determined to be 2.701 g.

[00146] 2.701 g of MoO ₃ is added to the wet Zr because Zr: MoO ₃ forms a 50:50 slurry by weight. Excess water was added to the wet Zr and MoO ₃ slurry to obtain a reaction slurry containing 50.2% DI water. The reaction slurry was mixed for 5 minutes using an IKA Ultra-Turrax mixing motor with S25N-8G dispersion head (setting 4). To the slurry was added 15% Laponite® RDS (1.816 g to provide a final mixture of fuel, water and Laponite consisting of 2.4% Laponite). The slurry was mixed for an additional 5 minutes using an IKA Ultra-Turrax mixer.

[Example 2]
Embodiments of initiator composition
[00147] The initiator composition consisted of 8.6 mL of a uniform 4.25% Viton A500 (Dupont) / amyl acetate solution, 0.680 g Al (40-70 nm, Argonide) and 1.320 g MoO. It was prepared by adding to a mixture of ₃ (nano-sized mold, Climax Polybenum) and 0.200 g boron (nano-sized mold, Aldrich) and mixing well with a homogenizer blade. The mixture is homogenized at speed 1 for 30 seconds and then at speed 2 for 4 minutes.

[Example 3]
Ignition device manufacturing
[00148] The igniter assembly is printed along the length of the circuit board and has 0.03 inch diameter openings at one end, each with two copper tracings of 0.35 inch by 1.764 inch. Cleaned 0.005 inch thick FR-4 printed circuit board (1.820 inches x 0.25 inch), one on each side of the hole, and installed across the opening on the printed circuit board Constructed with 0.0008 inch diameter nichrome wire soldered to gold plated copper tracing.

[00149] initiator composition, a uniform 4.25% Viton A500 / amyl acetate solution of 8.6 mL, and 0.680g of Al (40~70nm, Argonide), MoO 3 of 1.320 g (nano It was prepared by adding to a mixture of size mold (Climax Molybenum) and 0.200 g boron (nanosize mold, Aldrich) and mixing well with a homogenizer blade. A 1.1 μL drop of initiator composition was dropped onto the nichrome wire above the hole using a Cavro syringe pump. The initiator composition was air dried for 10 minutes. The igniter was inverted and an additional 0.8 μL drop of initiator composition was dropped on the other side of the line. The composition was air dried for at least 10 minutes.

[Example 4]
Ignition device thermal stability
[00150] Twenty-nine igniters prepared in Example 3 were heated at 100 ° C for 4 hours, and 32 igniters prepared in Example 3 were heated at 100 ° C for 6 hours. It was. The igniter heated for 4 hours is heated at 100 ° C. for 30 minutes, then exposed to dry air at room temperature, heated again at 100 ° C. for 30 minutes, again exposed to dry air at room temperature, and finally Heated at 100 ° C. for 3 hours. The igniter was lit and the light intensity (V-sec) per igniter was measured as described in Example 7 below and compared to 63 controls that were not heated. No measurable difference was observed between the heat-treated and non-heated igniters.

[Example 5]
Ignition device freeze stability
[00151] The 18 igniters prepared in Example 3 were placed in scintillation glass bottles and then covered tightly to prevent condensation. The glass bottle was wrapped with aluminum foil and placed in a -20 ° C freezer for 48 hours. The igniter was lit and the luminosity (V-sec) for each igniter was measured as described in Example 7 below and compared to 63 controls that were not frozen. No measurable difference was observed between frozen and non-frozen igniters.

[Example 6]
Mechanical stability of the ignition device
[00152] Six igniters prepared in Example 3 etc. were vortexed for 24 hours, and 8 igniters prepared in Example 3 etc. were vortexed for 48 hours at high speed. (Speed 7, VWR 22830). The igniter was analyzed microscopically before and after vortexing and evaluated for changes in morphology, cracks, and / or delamination. No difference was observed between the vortex stirred igniter and the untreated igniter.

[Example 7]
Measuring the light intensity from the igniter
[00153] The initiator composition was activated and the light intensity was measured by monitoring the time history of the energy released from actuation of the initiator composition.

  [00154] The igniter was prepared in principle as described in Example 3 using the various compositions of the present invention.

  [00155] To measure light intensity from ignition device actuation, a photodetector (Newport, 818-IR) is used as shown in FIG. 2, and the time history of light intensity is recorded by an oscilloscope (Tektronix, TDS3014B). It was. The voltage output signal from the photodetector is proportional to the light intensity at a predetermined wavelength.

[00156] The igniter was ignited using two A76 batteries (3.13 V total). Representative graphs of strength versus time (ms) are shown in FIGS. 3A and 3B for the initiator compositions of the present invention. FIG. 3A shows an initiator composition comprising a mixture of 0.4 μL nano-Zr: nano-MoO ₃ (50:50) and 1 μL nano-Zr: micro-MoO ₃ (50:50) using a nitrocellulose binder. FIG. 3B is a graph from an initiator composition as prepared in Example 2.

[Example 8]
Heating unit embodiment with a resistance ignition device
[00157] A heating unit according to FIGS. 6A-6B was manufactured and performance was evaluated.

[00158] The following procedure is 76.16% of Zr: 19.04% of the _MoO 3: was used 4.8% Laponite (R) for the preparation of a solid fuel coatings comprising RDS.

  [00159] To prepare wet zirconium (Zr), an as-obtained suspension of Zr in DI water (Chemall, Germany) was stirred on a rotating mixer for 30 minutes. 10-40 mL of wet Zr was dispensed into a 50 mL centrifuge tube and centrifuged at 3200 rpm for 30 minutes (Sorvall 6200RT). DI water was removed to leave wet Zr pellets.

  [00160] To prepare a 15% Laponite® RDS solution, 85 grams of DI water was added to a beaker. During stirring, 15 grams of Laponite® RDS (Southern Clay Products, Gonzalez, TX) was added and the suspension was stirred for 30 minutes.

[00161] The reaction slurry was prepared by first removing the wet Zr pellet as previously prepared from the centrifuge tube and placing it in a beaker. After weighing the wet Zr pellets, the weight of the dry Zr is:
Dry Zr (g) = 0.8234 (wet Zr (g)) − 0.1059
Determined from.

[00162] The amount of molybdenum trioxide to obtain a ratio of Zr to MoO ₃ of 80:20, eg, MoO ₃ = dry Zr (g) / 4, was then determined and the appropriate amount of MoO ₃ powder (Accumet , NY) was added to a beaker containing wet Zr to produce a wet Zr: MoO ₃ slurry. In order to obtain a final dry ingredient weight percent ratio of 76.16% Zr: 19.04% MoO ₃ : 4.80% Laponite® RDS, the amount of Laponite® RDS was It has been determined. Excess water was added to the wet Zr and MoO ₃ slurry to obtain a reaction slurry containing 40% DI water. The reaction slurry was mixed for 5 minutes using an IKA Ultra-Turrax mixing motor with S25N-8G dispersion head (setting 4). The previously determined amount of 15% Laponite® RDS was then added to the reaction slurry and mixed for an additional 5 minutes using an IKA Ultra-Turrax mixer. The reaction slurry is transferred to a syringe and accumulated for at least 30 minutes before coating.

[00163] A reaction slurry of Zr: MoO ₃ : Laponite® RDS was then coated onto the stainless steel foil. The stainless steel foil was first cleaned by sonication for 5 minutes with a 3.2% bv solution of Ridoline 298 in DI water at 60 ° C. The stainless steel foil was masked with 0.215 inch wide Mylar® so that the center of each 0.004 inch thick 304 stainless steel foil was exposed. The foil was placed in a vacuum chuck with a 0.008 inch thick shim at the edge. 2 mL of the reaction slurry was placed on one edge of the foil. Using a Sheen Auto-Draw Automatic Film Applicator 1137 (Shen Instruments), the reaction slurry was used to deposit an approximately 0.006 inch thick layer of Zr: MoO ₃ : Laponite® RDS reaction slurry. The entire surface was coated on the foil by pulling a # 12 coating rod with an automatic draw coating speed of up to 50 mm / sec. The coated foil was then placed in a forced air convection oven at 40 ° C. and dried for at least 2 hours. The mask is then removed from the foil to leave a solid fuel coating in the center of each foil.

  [00164] The spacer is composed of a 0.24 inch thick section of polycarbonate (Makronlon).

[00165] The igniter assembly consisted of an FR-4 printed circuit board having a 0.03 inch diameter opening at the end to be placed in the enclosure defined by the spacer and the substrate. A 0.0008 inch diameter nichrome wire was soldered to a conductor on the printed circuit board and placed across the opening. An initiator composition comprising 26.5% Al, 51.4% MoO ₃ , 7.7% B, and 14.3% Viton A500 in dry weight percent is deposited and dried on nichrome wire. It was.

  [00166] To assemble the heating unit, a nichrome wire containing the initiator composition was placed at one end of the solid fuel region. Epoxy beads (Epo-Tek 353ND, Epoxy Technology) were applied to both sides of the spacer, and the spacer, substrate, and igniter assembly were placed and pressed. The epoxy was cured at a temperature of 100 ° C. for 3 hours.

  [00167] To ignite the solid fuel, a 0.4 amp current was supplied to the conductor connected to the nichrome wire.

  [00168] Measurements on such a heating unit have demonstrated that the outer surface of the substrate reaches a temperature in excess of 400 ° C. in less than 150 milliseconds after activation of the initiator. The maximum pressure in the enclosure is less than 10 psig. Separate measurements have demonstrated that the enclosure can withstand static pressures in excess of 60 psig at room temperature. The combustion propagation rate over one side of the solid fuel was measured to be 25 cm / sec.

[Example 9]
Heating unit embodiment with an optical igniter using an initiator composition
[00169] A heating unit according to Figure 7A was fabricated and performance was evaluated.

[00170] The following procedure is 76.16% of Zr: 19.04% of the _MoO 3: was used 4.8% Laponite (R) for the preparation of a solid fuel coatings comprising RDS.

  [00171] To prepare wet zirconium (Zr), an as-obtained suspension of Zr in DI water (Chemall, Germany) was stirred on a rotating mixer for 30 minutes. 10-40 mL of wet Zr was dispensed into a 50 mL centrifuge tube and centrifuged at 3200 rpm for 30 minutes (Sorvall 6200RT). DI water was removed to leave wet Zr pellets.

  [00172] To prepare a 15% Laponite® RDS solution, 85 grams of DI water was added to a beaker. During stirring, 15 grams of Laponite® RDS (Southern Clay Products, Gonzalez, TX) was added and the suspension was stirred for 30 minutes.

[00173] The reaction slurry was prepared by first removing the wet Zr pellet as previously prepared from the centrifuge tube and placing it in a beaker. After weighing the wet Zr pellets, the weight of the dry Zr is:
Dry Zr (g) = 0.8234 (wet Zr (g)) − 0.1059
Determined from.

[00174] The amount of molybdenum trioxide to obtain a ratio of Zr to MoO ₃ of 80:20, eg, MoO ₃ = dry Zr (g) / 4, was then determined and the appropriate amount of MoO ₃ powder (Accumet , NY) was added to a beaker containing wet Zr to produce a wet Zr: MoO ₃ slurry. In order to obtain a final dry ingredient weight percent ratio of 76.16% Zr: 19.04% MoO ₃ : 4.80% Laponite® RDS, the amount of Laponite® RDS was It has been determined. Excess water was added to the wet Zr and MoO ₃ slurry to obtain a reaction slurry containing 40% DI water. The reaction slurry was mixed for 5 minutes using an IKA Ultra-Turrax mixing motor with S25N-8G dispersion head (setting 4). The previously determined amount of 15% Laponite® RDS was then added to the reaction slurry and mixed for an additional 5 minutes using an IKA Ultra-Turrax mixer. The reaction slurry is transferred to a syringe and accumulated for at least 30 minutes before coating.

[00175] A reaction slurry of Zr: MoO ₃ : Laponite® RDS was then coated onto the stainless steel foil. The stainless steel foil was first cleaned by sonication for 5 minutes with a 3.2% bv solution of Ridoline 298 in DI water at 60 ° C. The stainless steel foil was masked with 0.215 inch wide Mylar® so that the center of each 0.004 inch thick 304 stainless steel foil was exposed. The foil was placed in a vacuum chuck with a 0.008 inch thick shim at the edge. 2 mL of the reaction slurry was placed on one edge of the foil. Using a Sheen Auto-Draw Automatic Film Applicator 1137 (Shen Instruments), the reaction slurry was used to deposit an approximately 0.006 inch thick layer of Zr: MoO ₃ : Laponite® RDS reaction slurry. The entire surface was coated on the foil by pulling a # 12 coating rod with an automatic draw coating speed of up to 50 mm / sec. The coated foil was then placed in a forced air convection oven at 40 ° C. and dried for at least 2 hours. The mask is then removed from the foil to leave a solid fuel coating in the center of each foil.

[00176] initiator composition is a 4.25% Viton A500 / amyl acetate solution of 8.6 mL, and 0.680g of Al (40 to 70 nm), MoO ₃ of 1.320g and (nano), 0. It was prepared by adding to a mixture of 200 g boron (nano) and mixing well. A 1.1 μL drop of initiator composition was placed in a 0.06 inch diameter hole in a 1.5 inch × 1.75 inch fiber glass mat (0.04 inch thick, direct light). A drop of initiator composition was placed in the hole from each side of the fiberglass mat.

  [00177] To assemble the heating unit, double-sided tape (2 "x 2.25" x 0.375 "wide, Saint-Gobain Performance Plastics) was attached to the fuel coated foil (2" x 2 "). Spacers (2 inches x 2.25 inches x 0.1 inches thick, Makrolon) were attached to the double-sided tape. First, a fiberglass mat with an initiator, then two other fiberglass mats with holes (0.1 inch diameter) were placed in the spacer and positioned so that the holes in the fiberglass mat were aligned. . Double-sided tape was attached to the other side of the spacer. This was then covered with a 2 inch x 2.25 inch window made of clear plastic (1/16 inch polycarbonate sheet, McMaster-Carr).

  [00178] The heating unit was ignited by pulsed flash light from a xenon lamp powered by a single AA battery associated with an electronic circuit.

[Example 10]
Heating unit embodiment with an impact igniter using an initiator composition
[00179] The preparation of the heating unit according to Fig. 8 using collision ignition is described below.

[00180] The next step is 76.16% of Zr: 19.04% of the _MoO 3: is used for preparing a liquid fuel coatings comprising 4.8% Laponite (R) RDS.

  [00181] To prepare wet zirconium (Zr), an as-obtained suspension of Zr in DI water (Chemall, Germany) was stirred on a rotating mixer for 30 minutes. 10-40 mL of wet Zr was dispensed into a 50 mL centrifuge tube and centrifuged at 3200 rpm for 30 minutes (Sorvall 6200RT). DI water was removed to leave wet Zr pellets.

  [00182] To prepare a 15% Laponite® RDS solution, 85 grams of DI water was added to a beaker. During stirring, 15 grams of Laponite® RDS (Southern Clay Products, Gonzalez, TX) was added and the suspension was stirred for 30 minutes.

[00183] The reaction slurry was prepared by first removing the wet Zr pellet as previously prepared from the centrifuge tube and placing it in a beaker. After weighing the wet Zr pellets, the weight of the dry Zr is:
Dry Zr (g) = 0.8234 (wet Zr (g)) − 0.1059
Determined from.

[00184] The amount of molybdenum trioxide to obtain a ratio of Zr to MoO ₃ of 80:20, eg, MoO ₃ = dry Zr (g) / 4, was then determined and the appropriate amount of MoO ₃ powder (Accumet , NY) was added to a beaker containing wet Zr to produce a wet Zr: MoO ₃ slurry. In order to obtain a final dry ingredient weight percent ratio of 76.16% Zr: 19.04% MoO ₃ : 4.80% Laponite® RDS, the amount of Laponite® RDS was It has been determined. Excess water was added to the wet Zr and MoO ₃ slurry to obtain a reaction slurry containing 40% DI water. The reaction slurry was mixed for 5 minutes using an IKA Ultra-Turrax mixing motor with S25N-8G dispersion head (setting 4). The previously determined amount of 15% Laponite® RDS was then added to the reaction slurry and mixed for an additional 5 minutes using an IKA Ultra-Turrax mixer. The reaction slurry is transferred to a syringe and accumulated for at least 30 minutes before coating.

[00185] A reaction slurry of Zr: MoO ₃ : Laponite® RDS was then coated onto the stainless steel foil. The stainless steel foil was first cleaned by sonication for 5 minutes with a 3.2% bv solution of Ridoline 298 in DI water at 60 ° C. The stainless steel foil was masked with 0.215 inch wide Mylar® so that the center of each 0.004 inch thick 304 stainless steel foil was exposed. The foil was placed in a vacuum chuck with a 0.008 inch thick shim at the edge. 2 mL of the reaction slurry was placed on one edge of the foil. Using a Sheen Auto-Draw Automatic Film Applicator 1137 (Shen Instruments), the reaction slurry was used to deposit an approximately 0.006 inch thick layer of Zr: MoO ₃ : Laponite® RDS reaction slurry. The entire surface was coated on the foil by pulling a # 12 coating rod with an automatic draw coating speed of up to 50 mm / sec. The coated foil was then placed in a forced air convection oven at 40 ° C. and dried for at least 2 hours. The mask is then removed from the foil to leave a solid fuel coating in the center of each foil.

[00186] thin stainless steel wire igniter assembly comprising (wire anvil) is, Al of 26.5% in weight percent based on the dry weight 51.4 percent _MoO 3, 7.7% of the B and,, 14 Dip coat 1/4 on the initiator composition in amyl acetate containing 3% Viton A500. The coated wire is then dried at about 40-50 ° C. for 1 hour. The dried coated wire was placed in an ignition tube (soft wall aluminum tube, 0.003 inch wall thickness) and crimped at one end to keep the wire in place.

  [00187] To assemble the heating unit, the ignition tube was placed between two fuel-coated foil substrates (fuel chips) and the open end of the ignition tube was aligned with the edge of the fuel coating on the fuel chip. The fuel chip was sealed with aluminum adhesive tape.

  [00188] To ignite the solid fuel, the fuel tube is struck with a brass rod.

  [00189] In an alternative embodiment of this Example 10, the igniter assembly includes 620 parts by weight titanium (size less than 20 μm), 100 parts by weight potassium chlorate, 180 parts by weight red phosphorus, Constructed by a thin stainless steel wire (wire anvil) dip coated in an initiator composition containing 100 parts by weight sodium chlorate and 620 parts by weight water with 2% polyvinyl alcohol binder. . The coated wire is then dried at 40-50 ° C. for 1 hour. The dried coated wire was placed in an ignition tube (soft wall aluminum tube, 0.003 inch wall thickness) and crimped at one end to keep the wire in place.

  [00190] Although the present invention has been described within the context of heating units for use in medical devices with respect to particular embodiments, these initiator compositions and igniters can be used as low outgassing compositions and / or It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the invention, such as application to various other systems requiring either low voltage ignition device.

1 is a schematic view of an igniter comprising an initiator composition disposed on an electrical resistance heating element. FIG. 1 is a schematic diagram of a photodetector system used to measure the luminosity of an igniter and initiator composition. FIG. Figure 2 is a graph of light intensity versus time for one of a mixture of two compositions. FIG. 4 is a graph of the other light intensity versus time for a mixture of two compositions. FIG. It is sectional drawing of the heating unit by a certain embodiment. It is sectional drawing of the heating unit by a certain embodiment. It is a perspective view of the heating unit by a certain embodiment. It is sectional drawing of the heating unit which has a cylindrical shape by a certain embodiment. FIG. 5B is a cross-sectional view of a cylindrical heating unit similar to the heating unit of FIG. 5A that also has a modified igniter design according to certain embodiments. FIG. 3 is a perspective view of a heating unit according to an embodiment operated by electrical resistance. FIG. 2 is an assembly view of a heating unit according to an embodiment operated by electrical resistance. FIG. 3 is a perspective view of a heating unit according to an embodiment operated by optical ignition. FIG. 3 is a perspective view of a heating unit according to an embodiment operated by optical ignition. FIG. 2 is a schematic diagram of a heating unit according to an embodiment operated by impact ignition.

Claims (60)

A highly reliable high spark initiator composition comprising:
a. i. Metal-containing oxidant,
ii. At least one metal reducing agent; and
iii. Contains a mixture of non-explosive binders,
b. The mixture has a composition thickness between about 20 and 100 microns, a total energy release between 0.25 J and 8.5 J upon actuation, and a range of 5 to 30 milliseconds. Characterized by the deflagration time between,
High reliability high spark initiator composition.   The initiator composition of claim 1, wherein the deflagration time is less than 20 milliseconds.   The initiator composition of claim 1, wherein the deflagration time is less than 10 milliseconds.   The initiator composition of claim 1, wherein the at least one metal reducing agent is selected from the group consisting of aluminum, zirconium, and boron.   The metal-containing oxidizing agent is selected from the group consisting of alkali chlorates, alkaline earth metal chlorates, alkali metal perchlorates, alkaline earth metal perchlorates, and metal oxides. The initiator composition according to claim 1, which is selected.   The initiator composition according to claim 5, wherein the oxidizing agent is selected from at least one of molybdenum trioxide, copper oxide, tungsten trioxide, potassium chlorate, and potassium perchlorate.   The initiator composition of claim 1 comprising at least two metal reducing agents.   The initiator composition according to claim 7, wherein at least one of the two metal reducing agents is boron.   9. The initiator composition of claim 8, wherein the boron is present from about 7 to 10% by weight relative to other oxidizing and reducing agents in the mixture.   The initiator composition of claim 1, wherein the metal reducing agent and the metal-containing oxidizing agent comprise a powder.   The initiator composition according to claim 10, wherein at least one of the powders has a nanoparticle size.   The initiator composition according to claim 10, wherein both the metal reducing agent and the metal-containing oxidizing agent are nanoparticle-sized powders.   The initiator composition of claim 1 comprising 25 to 75 wt% of the oxidizing agent.   The initiator composition according to claim 1, comprising 25 to 75% by weight of the reducing agent.   The initiator composition of claim 1, comprising less than about 15 weight percent binder based on the total dry weight of the composition.   The initiator composition of claim 1, comprising less than 5 weight percent binder based on the total dry weight of the composition.   The initiator composition of claim 15, wherein the binder is inert.   The initiator composition of claim 17, wherein the binder is selected from the group consisting of Viton or Laponite.   The initiator composition of claim 1 for use with an electrical resistance actuation mechanism.   The initiator composition of claim 1 for use with impact actuation.   The initiator composition of claim 1 for use with optical actuation.   23. The initiator composition of claim 22, wherein the optical actuation is a flash bulb.   The initiator composition of claim 1 comprising aluminum, molybdenum trioxide, boron, and Viton.   High reliability, high, comprising about 26-27% aluminum, 51-52% molybdenum trioxide, 7-8% boron, and 14-15% Viton, based on the total dry weight of the composition Spark, low voltage, non-explosive initiator composition. a. A support in which a hole is contained,
b. At least two conductors in contact with the support;
c. A resistive heating element positioned at least partially across the hole and attached to the conductor;
d. An initiator composition positioned on at least a portion of both sides of the resistance heating element and covering the hole;
A highly reliable electric ignition device that ignites fuel and forms a concentrated jet in both directions.   26. The igniter of claim 25, wherein the support is a thermally insulating material.   27. The igniter of claim 26, wherein the thermal insulation material is selected from the group consisting of Kapton®, fluorine laminate material, or FR4 epoxy / fiberglass printed circuit board.   26. The igniter of claim 25, wherein the conductor is copper tracing.   26. The igniter according to claim 25, wherein the resistance heating element is selected from a metal or an alloy.   30. The igniter of claim 29, wherein the resistive heating element is in the form of a wire, filament, ribbon, or foil.   31. The igniter according to claim 30, wherein the resistance heating element is a nichrome wire.   32. The igniter of claim 31, wherein the wire has a diameter of about 0.0006 inches to about 0.001 inches.   32. The igniter of claim 31, wherein the resistive heating element has an electrical resistance between about 2Ω and 4Ω.   26. The ignition device of claim 25, wherein the conductor is attached to the resistance heating element by soldering.   26. The igniter of claim 25, wherein the initiator composition is a slurry.   26. The igniter of claim 25, wherein the initiator composition is non-explosive.   26. The igniter of claim 25, wherein the initiator composition is low gas production. The initiator composition is
a. Metal-containing oxidant,
ii. At least one metal reducing agent; and
iii. 26. The igniter of claim 25, comprising a mixture of non-explosive binders.   26. The ignition of claim 25, wherein the initiator composition comprises, by weight of dry solids, 10-20 percent binder, 30-40 percent reducing agent, and 40-60 percent metal-containing oxidizing agent. apparatus.   26. The igniter of claim 25, wherein the initiator composition comprises a mixture of boron, aluminum, molybdenum trioxide, and Viton.   26. The igniter of claim 25, characterized by the onset of deflagration in less than 50 milliseconds upon actuation.   26. The igniter of claim 25, characterized by the onset of deflagration in less than 10 milliseconds upon actuation.   26. The igniter of claim 25, characterized by the onset of deflagration in less than 6 milliseconds upon actuation. A method of manufacturing a highly reliable ignition device that concentrates ejection in both directions during ignition,
a. Depositing two conductors on a support in which holes are received;
b. Attaching a resistance heating element positioned across the hole between the conductors;
c. Dispensing an initiator composition on one side of the resistive heating element so as to cover at least a portion of the hole on the support;
d. Drying the dispensed initiator composition;
e. Distributing the initiator composition once more to the opposite side of the resistive heating element and to the holes from the first distribution so as to cover the holes;
f. Drying the initiator composition dispensed a second time;
A method comprising:   45. The method of claim 44, wherein the support is a thermally insulating material.   46. The method of claim 45, wherein the thermally insulating material is selected from the group consisting of Kapton (R) or FR4 epoxy / fiberglass printed circuit boards.   45. The method of claim 44, wherein the conductor is copper tracing.   45. The method of claim 44, wherein the resistance heating element is selected from a metal or an alloy.   45. The method of claim 44, wherein the resistive heating element is in the form of a wire, filament, ribbon, or foil.   45. The method of claim 44, wherein the resistive heating element is a nichrome wire.   52. The method of claim 51, wherein the wire has a diameter between about 0.0006 inches and about 0.001 inches.   52. The method of claim 51, wherein the resistive heating element has an electrical resistance between about 2Ω and 4Ω.   45. The method of claim 44, wherein the drying is air drying.   45. The method of claim 44, wherein the attachment comprises soldering.   45. The method of claim 44, wherein the initiator composition comprises a slurry.   45. The method of claim 44, wherein the initiator composition is non-explosive.   45. The method of claim 44, wherein the initiator composition is low gas production.   45. The method of claim 44, wherein the dispensing is by an automatic dispensing device. The initiator composition is
a. Metal-containing oxidant,
b. At least one metal reducing agent; and
c. 45. The method of claim 44, comprising a mixture of non-explosive binders.   45. The method of claim 44, wherein the initiator composition comprises a mixture of boron, aluminum, molybdenum trioxide, and Viton.

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