Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B43/00—Compositions characterised by explosive or thermic constituents not provided for in groups C06B25/00 - C06B41/00
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06D—MEANS FOR GENERATING SMOKE OR MIST; GAS-ATTACK COMPOSITIONS; GENERATION OF GAS FOR BLASTING OR PROPULSION (CHEMICAL PART)
  • C06D5/00—Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets
  • C06D5/06—Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets by reaction of two or more solids

Definitions

• Gas generators are being used increasingly, for example in vehicles to save lives.
• the gas-generating mixture usually contains sodium azide.
• Natriu azid in itself is toxic and can easily mix with heavy metals such as.
• B. Implement copper and lead to form extremely dangerous and violently reacting compounds. Special measures must therefore be taken in the manufacture of the raw material, the gas mixture, its processing and quality control. For this reason, the disposal of the sodium azide, for example when replacing defective gas generators or when scrapping the vehicles, is also a particular problem. Misuse must also be prevented.
• EP 0 519 485 describes the use of tetrazole or tetrazole derivative (s) or the use of one or more compounds from the group of cyanic acid derivatives and their salts, one or more compounds from the group of triazine and triazine derivatives of urea, its salts, derivatives and derivatives and salts of these compounds, it being possible for the compounds mentioned to also be present as mixtures.
• Nitrates of ammonium, sodium, potassium, magnesium, calcium and iron and / or peroxides of zinc, calcium, strontium or magnesium can be used as the oxidizing agent. Further gas-generating components, coolants, reducing agents, catalysts and / or porosity generators can be added.
• EP 0 438 851 describes a non-toxic, non-acidic pyrotechnic composition which is suitable for use in the generation of essentially non-toxic combustion Products including a gas is suitable for filling an accident cushion.
• the composition comprises a mixture of at least one tetrazole or triazole compound which contains hydrogen in the molecule, at least one oxygen-containing oxidizing agent and at least one metal oxide selected from cobalt oxide, nickel oxide, chromium oxide, aluminum oxide or boron oxide.
• the combustion produces an essentially non-toxic primary gas mixture and unfilterable solids.
• aminotetrazole is used with oxidizing agents, which in addition to nitrites can also contain perchlorates.
• Oxohalates are understood to mean, for example, chlorates, bromates and their per compounds of the alkali metals.
• combustion-regulating catalysts u. a. mentioned: oxides, chlorides, carbonates, sulfonates of the 4th to 6th rows of the periodic table.
• the gas resulting from the reaction is passed through a Venturi nozzle to improve the yield, so that outside air can be used to inflate the airbag.
• this outside air strongly removes the hot gases. cools.
• the volume loss that occurs as a result of this for inflating the gas bag must be compensated for by the pyrotechnic mixture.
• the increased proportion of toxic swaths inside the vehicle can no longer be reduced sufficiently by thinning.
• the present invention describes non-toxic, azide-free mixtures for gas generation by combustion.
• These gas-generating mixtures can include in safety devices, for example in airbag systems for inflating airbags in vehicles and airplanes. However, they are also suitable for lifting heavy loads by inflating sacks underneath or for driving out z.
• the mixtures according to the invention contain
• a) as nitrogen-containing compound (fuel) at least one compound from the group tetrazoles, triazoles, triazines, cyanic acid, urea, their derivatives, derivatives or their salts,
• combustion moderators which are suitable for influencing the combustion and its speed by heterogeneous or homogeneous catalysis, and, if appropriate
• the mixtures according to the invention are non-toxic and, in contrast to mixtures containing azide, are easy to handle. They therefore require less security effort at the Production of the raw materials and mixtures and their shaping, storage or disposal.
• the nitrogen-containing compounds to be used according to the invention are those which, when mixed with oxidizing agents during their thermal / chemical conversion, form mainly CO2, N 2 ° 2 and H 2 ⁇ , but do not develop gases such as CO or N0 ⁇ in concentrations which are hazardous to health.
• the mixtures according to the invention preferably contain nitrogenous compounds (fuels)
• R, and R 7 or R3 may be the same or different, but either R2 or R3 is present and have the meaning: hydrogen, hydroxy, amino, carboxyl, an alkyl radical having 1 to 7 carbon atoms, an alkenyl radical having 2 to 7 carbon atoms, one Alkylamino radical with 1 to 10 carbon atoms, an aryl radical, optionally substituted with one or more substituents, which can be the same or different and are selected from the amino group, the nitro group, the alkyl radicals with 1 to 4 carbon atoms or an arylamino radical which may optionally be substituted for the aryl radical or the sodium, potassium and guanidinium salts of the tetrazole derivatives mentioned.
• R ⁇ preferably hydrogen, A ino, hydroxy, carboxyl, a methyl, ethyl, propyl or isopropyl, butyl, isobutyl or tert-butyl, n-pentyl, n-hexyl or n-heptyl radical, a methylamino, ethylamino, dimethylamino, n-heptylamino, n-octylamino or n-decylamino radical, a tetrazole radical, a phenylamino radical, a phenyl, nitrophenyl or aminophenyl radical;
• R2 or R3 is preferably hydrogen, a methyl or ethyl radical, a phenyl, nitrophenyl or aminophenyl radical.
• tetrazole derivatives 5-aminotetrazole, lithium, sodium, potassium, zinc, magnesium, strontium or calcium 5-aminotetrazolate, 5-aminotetrazole nitrate, sulfate, perchlorate and similar compounds are particularly preferred, l- (4-aminophenyl) tetrazole, l- (4-nitrophenyl) tetrazole, l-methyl-5-dimethylaminotetrazole, l-methyl-5-methylaminotetrazole, 1-methyltetrazole, l-phenyl- 5-aminotetrazole, l-phenyl-5-hydroxy-tetrazole, 1-phenyltetrazole, 2-ethyl-5-aminotetrazole, 2-methyl-5-aminotetrazole, 2-methyl-5-carboxyltetrazole, 2-methyl- 5- methylaminotetrazole, 2-methyltetrazole, 2-phenyltetrazole, 5- (p-tolyl) -
• 5-Aminotetrazole is used as a particularly preferred component.
• the preferred proportion when using this component in the mixture is 10-40% by weight.
• Its salts are used as derivatives of 5-aminotetrazole, in which the acidic hydrogen atoms on 5-aminotetrazole are replaced like salts by toxicologically harmless elements such as calcium, magnesium or zinc.
• the cation is formed from ammonium, guanidinium and its amino derivatives.
• Oxohalogen compounds of alkali or alkaline earth metals or ammonium particularly preferably potassium perchlorate or ammonium perchlorate.
• the oxidizing agents can be used individually or in mixtures. In order to reduce the nitrogen oxide content in the reaction gases as much as possible, it is advantageous to keep the nitrate content in the oxidant mixtures as low as possible, since some of the nitrates can thermally decompose.
• a preferred combination of the oxidizing agents consists of zinc peroxide, potassium perchlorate and at least one nitrate, preferably sodium nitrate or strontium nitrate in a mixing ratio of 1: 2: 10 and a total proportion of approximately 60% by weight in the gas-generating mixture.
• the chlorine-containing compounds react during the burning to form harmless sodium / potassium chloride.
• Ammonium perchlorate alone or in a mixture with another can also be used as perchlorate Oxohalogen compound are provided, but an excess must be avoided in order to rule out the formation of aggressive hydrochloric acid. If ammonium perchlorate is used, the simultaneous presence of zinc compounds is particularly advantageous since the risk of hydrochloric acid formation can thereby be avoided. An excess of sodium and potassium compounds is harmless since this reacts with the reaction gases to form harmless carbonates.
• the partial or complete replacement of the alkali nitrate with strontium nitrate leads to a significant reduction in the slag content.
• the mixing ratio of the nitrogen-containing compounds, for example the tetrazoles and triazoles, to the oxidizing agents is balanced so that an excess of oxygen is formed when the gas mixture is burned off. This excess of oxygen shifts the CO / CO 2 equilibrium towards carbon dioxide.
• Moderators who intervene in the implementation in the form of heterogeneous catalysis are metals, metal oxides and / or metal carbonates and / or metal sulfides. Boron, silicon, copper, iron, titanium, zinc or molybdenum can preferably be used as metals. Calcium carbonate can also be used. Mixtures of these moderators can also be used.
• Moderators who intervene in the implementation in the form of homogeneous catalysis are, for example, sulfur, boron, silicon or ferrocene and its derivatives. These moderators are vaporized into the gas phase by the temperatures occurring during the reaction and can intervene in the reaction itself or as secondary products. The proportion of these substances in the mixture can be up to approx. 8%.
• the mixture according to the invention for gas production can contain additives which are suitable for the proportion of To reduce harmful gases such as nitrogen oxides and / or carbon monoxide.
• the proportion of these harmful gases in the gas mixture generated is determined by
• additives are used whose chemical properties catalyze the conversion of nitrogen oxides in particular, for example nitrogen dioxide to nitrates or nitrites.
• nitrogen oxides in particular, for example nitrogen dioxide to nitrates or nitrites.
• all more or less strongly reacting substances are suitable. These include, for example, oxides, hydroxides or carbonates of non-toxic elements such as those of the alkali and alkaline earth metals, that of zinc, and mixtures of these compounds.
• oxides, hydroxides or carbonates of non-toxic elements such as those of the alkali and alkaline earth metals, that of zinc, and mixtures of these compounds.
• urea, guanidine and its derivatives compounds with NH 2 groups such as, for example, amidosulfonic acids, amido complexes and the like, and A ide for reaction with NO 2.
• a particularly preferred embodiment provides the use of peroxides in the outflow openings of the generators ren. It is particularly advantageous here that, in addition to the reduction of the nitrogen oxides by the reactions described above, additional oxygen is formed for the subsequent catalytic reaction with carbon monoxide.
• the supplements according to the invention can be introduced alone or together directly into the gas-generating set or can be provided in the outflow ducts of the generator.
• a compressed application form of the additives for example in the form of tablets, pills or granules, is expedient for use in the outflow ducts of the generator.
• the amount of the supplements used is about 10% by weight.
• the amount of the aggregates in the outflow ducts can amount to up to 75% by weight, based on the gas charge.
• a reduction in the CO content can surprisingly also be achieved in that part of the fuel from the salts, preferably from the calcium, magnesium or zinc salts of aminotetrazole, preferably from the corresponding salts of 5-aminotetrazole or from Urea derivatives exist. In these cases, the use of only two oxidizing agents is sufficient.
• Additional additives can be added to influence the reaction rate and temperature.
• Such additives can be, for example, boron or metal powder, for example titanium, aluminum, zirconium, iron, copper, molybdenum, and their stable hydrides. Their share of the surcharges is of the order of 5% by weight.
• the gas charge mixtures according to the invention are produced in a manner known per se.
• the components are, for example, mixed dry, sieved, portioned and compressed into tablets.
• the rate of combustion can be adjusted via the grain shape and size of the bulk material obtained, for example, by breaking and sieving the fragments.
• the bulk material can be produced in large quantities and, by mixing fractions with different dynamic vivacity, can be adapted to the particular requirements during combustion. Premixes with 2 or 3 components can also be used to increase the safety or improve the mixing result.
• a mixture of oxidizing agent and additives can be prepared, for example, before it comes into contact with the nitrogen-containing compounds.
• the mixture can also be kneaded by moist components and subsequent granulation z. B. by passing sieves, extrusions or the like.
• Binders such as water glass, "inorganic rubber” (phosphonitrile chloride) or even small proportions of organic binders such as acrylic resins, PTFE, guar gu can be used. Since the components used are neither toxic nor particularly reactive and can only be brought into reaction with the aid of special igniters, special safety precautions are not necessary.
• the bulk material obtained in this way can be used immediately.
• the bulk material can be coated on the surface. This can be done by means of a varnish coating, which may be provided with additives that support the burning of the bulk material. Oxidation agents such as zinc peroxide, perchlorates and metal powders such as titanium and zircon can be considered as burn-in supports.
• the Aufbring gung can by spraying the solvent-containing coating agents such. B. in a drum with evaporation of the solvent.
• Porous grain structures can be used in the grain for special applications.
• Such porous structures can be produced by customary methods, for example by adding soluble salts and then releasing them with the appropriate solvents or by adding thermally decomposable substances such as ammonium bicarbonate, acetone dicarboxylic acid, blowing agents, peroxides or azobisisobutyronitrile, which then occur in a subsequent step Process step are removed again by heating and tempering at elevated temperature. The characteristic is determined by quantity, grain size and distribution.
• Such gas sets can be used, for example, when gas sets with a strongly progressive reaction are required.
• the ready-made gas set can be ignited using the usual methods. It is important that no additional toxic vapor components are released from the igniter after the reaction.
• the gas set mixture is insensitive to its safety-related characteristics, such as: B. against friction, impact and impact or flammability against flame or cerium / iron sparks under normal pressure. In the inclusion, on the other hand, it burns violently when lit appropriately. This increases safety during manufacture and handling.
• the mixtures according to the invention can be used, for example, in gas generators for automotive safety with the electrically triggered ignition systems customary there.
• the specified components for the gas sets according to the invention are homogenized in the specified weight ratios in plastic containers in a tumble mixer for 30 minutes. The mixtures are then tableted into compacts with a diameter of approximately 6 mm. 3.5 g of the tabletted samples are reacted in a 25 ml stainless steel pressure bomb using 0.2 g boron / potassium nitrate (25:75 parts by weight) as an ignition mixture and an electrically heated iron wire. The pressure-time profile of the reaction is registered via a piezoelectric measuring device. During the exothermic reaction, combustion gases are generated, which are mainly composed of H2O, CO2, N2 and O2 and meet the toxicological requirements.
• the gas set mixtures described in the examples are examined, for example, in a measuring device consisting of a combustion chamber, gas flow deflection and filter chamber under defined mechanical construction conditions with regard to the combustion characteristics.
• the gaseous reaction products are collected and characterized in a 60 1 volume (main components: H 2 0, C0 2 - N 2 and 0 2 )
• composition (% by weight
• Example 1 describes the reaction of 5-aminotetrazole (5-ATZ) with a binary mixture of oxidizing agents.
• the vapor composition shows a proportion of 1800 ppm CO in the reaction vapor after burning in a closed pressure bomb.
• Example 2 the addition of only 1% by weight of zinc peroxide surprisingly leads to a significant reduction in the CO content to 1100 ppm with otherwise unchanged test parameters.
• the changes in the composition of the mixtures in Examples 3 to 5 lead to poorer results.
• composition (% by weight)
• Measurement results in the 60 1 test can:
• reaction time is between 40 and 60% of the maximum pressure in milliseconds
• Examples 6 to 9 show that the addition of the Zn, Ca and Mg salts of 5-aminotetrazole (Me (5-ATZ) 2 ) has a favorable effect on the vapor composition. A clear reduction in the CO content is found. The reaction rate is also influenced. Composition (% by weight)
• reaction time is between 40 and 60% of the maximum pressure in milliseconds
• Examples 10 to 13 differ in the proportion of sodium nitrate / strontium nitrate as the oxidizing agent. With an increasing proportion of strontium nitrate, the mass of the slag emerging into the jug is reduced. This means that the filterability of the slag is improved by adding strontium nitrate - after the reaction - in the filter of the generator. At the same time, the CO content of the reaction gas can be influenced favorably.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Air Bags (AREA)
• Catalysts (AREA)
• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
• Treating Waste Gases (AREA)
• Manufacture And Refinement Of Metals (AREA)

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• 1995
  • 1995-02-18 DE DE19505568A patent/DE19505568A1/de not_active Withdrawn
• 1996
  • 1996-02-13 JP JP8525361A patent/JPH11500098A/ja active Pending
  • 1996-02-13 CN CN96193147A patent/CN1183758A/zh active Pending
  • 1996-02-13 TR TR97/00813T patent/TR199700813T1/tr unknown
  • 1996-02-13 CZ CZ0262197A patent/CZ298208B6/cs not_active IP Right Cessation
  • 1996-02-13 CA CA002211579A patent/CA2211579A1/en not_active Abandoned
  • 1996-02-13 MX MX9706223A patent/MX9706223A/es active IP Right Grant
  • 1996-02-13 WO PCT/EP1996/000605 patent/WO1996026169A1/de active IP Right Grant
  • 1996-02-13 PL PL96321832A patent/PL183318B1/pl not_active IP Right Cessation
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  • 1996-02-13 EP EP96902269A patent/EP0809616A1/de not_active Withdrawn
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  • 1996-02-13 RU RU97116160/02A patent/RU2250207C2/ru not_active IP Right Cessation
• 2006
  • 2006-11-17 US US11/561,128 patent/US20070102076A1/en not_active Abandoned

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