Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
  • C06C9/00—Chemical contact igniters; Chemical lighters

Definitions

• the present invention relates to early powder for thermal fuses for deenergized lighting of the gas set of an airbag gas generator of motor vehicles
• the gas sets used in airbag gas generators of motor vehicles are generally very thermally stable.
• thermal fuses In order to ignite the gas set at a high ambient temperature, for example in the event of a vehicle fire, so-called thermal fuses are used.
• the thermal fuse ensures that the finished gas generator is in front and after installation, e.g. in a motor vehicle, it is not ignited at an uncontrolled high temperature and then there may be a leak or even fragmentation of the gas generator housing - especially in the case of an aluminum housing. According to this, the thermal fuse ensures that the gas-generating elements are converted Mixture thermally drawn far below this critical temperature is prevented in such a case by its early implementation and controlled ignition of the gas set, the destruction of the gas generator housing and avoids the associated dangers
• a possible embodiment for a thermal fuse includes a container which is filled with an early powder powder (pyrotechnic mixture), for example in granular form (0.1 to 0.5 g), which preferably ignites between 150 ° C. and 200 ° C. and releases so much heat that the ignition of the actual lighter and / or the gas set is guaranteed
• pyrotechnic airbag gas generators are usually ignited by a current pulse by means of a sensor.
• the ignition is amplified by an ignition charge which, with the hot gas and solid particles generated, burns the actual gas set - often in tablet form - almost synchronously.
• the burning gas set delivers the full gas of the protective cushion
• the self-ignition temperature of the time 2 used gas sets are found in the azide halogens at around 400 ° C and in the azide-free ones
• nitrocellulose powders have been used as early powder for thermal fuses. These have a self-ignition temperature (decomposition point) of 150-200 ° C.
• the nitrocellulose powders do not meet the stability requirements that have recently been required by the automotive industry Over 400 hours at 107 ° C (224 ° Fahrenheit, US Pat. No. 5,460,671, column 3) with a weight loss of ⁇ 3% and maintaining full functionality, nitrocellulose tends to slowly decompose even at low temperatures and therefore does not guarantee the functionality as early spring powder over a longer period of time, as is necessary in motor vehicles
• thermal fuses which should be able to ignite the gas-generating mixtures usually used in gas generators in a thermally controlled manner well below the critical temperature and which do not have the disadvantages of nitrocellulose as substances or as substance mixtures for these thermal Fuses can be used for compounds selected from the oxalate, peroxodisulfate (persulfate), permanganate, nitride, perborate, bismuthate, formate, nitrate, sulfamate, bromate or peroxide compound classes.
• oxidizable components for example explosives
• low Nerpuffungs- or decomposition points preferably calcium-bistetrazole-amine, 3-roitro-l, 2,4-triazol-5-one (NTO), 5-aminotetrazole nitrate, nitroguanidine (NIGU), guanidine nitrate or bistra-tazolamine are used
• NTO 2,4-triazol-5-one
• NIGU nitroguanidine
• guanidine nitrate or bistra-tazolamine are used.
• the substances, which have a lower deflagration point or decomposition point have as the gas-generating mixture used, but decompose endothermically, require at least one fuel and possibly a reducing agent in order to be able to be used as a thermal fuse.
• fuels are the oxidizable components mentioned above.
• Metal powder preferably titanium powder, can be used as reducing agent
• oxidizing agents such as potassium nitrate or potassium
• US Pat. No. 5,460,671 describes ignition powders which consist of a mixture of a fuel and an oxidizing agent.
• the oxidizing agents are selected from the group consisting of alkali metal or alkaline earth metal chlorates or mixtures thereof, in particular potassium or sodium chlorate.
• the fuels are carbohydrates, such as D- Glucose, D-galactose, D-ribose, etc
• the present invention has for its object to provide early powder, which do not have the disadvantages of nitrocellulose described above and which meet the aforementioned stability requirements (ie weight loss ⁇ 3% when stored warm at 107 ° C for 400 hours) and when the gas generator overheats (at Temperatures above 240 ° C) with a small amount (0.1 to 0.5 g) of early ignition powder (in the early ignition unit) can ignite the airbag gas set
• At least one fuel selected from the group consisting of thiourea and its derivatives, such as N, N '-Diphenylthioharnstoff and thiocyanates of guanidines such as guanidine thiocyanate,
• processing aids selected from calcium and magnesium stearates, graphite, high-boiling paraffins (such as Naftolen P603 from Chemetall) and citric acid esters and acylcitric acid esters (such as triethyl citrate and acetyl triethyl citrate), and optionally
• auxiliary fuels selected from elemental aluminum, zirconium, titanium, magnesium, zinc and iron, and optionally
• (F) fillers selected from the group consisting of AI2O3, TLO2, Zr ⁇ 2, F e 2 ⁇ 3 > Si 3 N 4 and Bornit ⁇ d (BN)
• the fuel (A) is present in the spring powders according to the invention for thermal fuses in an amount of 20 to 40 parts by weight, preferably 25-35 parts by weight and in particular 28-32 parts by weight.
• Potassium chlorate and potassium rutate, potassium chlorate and potassium perchlorate as well as mixtures of these three oxidizing agents are present in an amount of 40-80 parts by weight, preferably 50-75 parts by weight and in particular 60-75 parts by weight.
• stabilizers (C) is hydroxyethyl cellulose (Natrosol 250 HR) Fa Aqualon) and cellulose acetobutyrate are particularly preferred.
• amide derivatives such as dicyandiamide (cyanoguanidine) according to the invention are to be paid for the polyamides as stabilizers (C).
• the stabilizers are in a proportion of 0.5-20 parts by weight, preferably 0.5-10 parts by weight and in particular 0.5-5 parts by weight.
• the early spring powders according to the invention can optionally contain processing aids (D) in an amount of 0.5-5 parts by weight, preferably 0.5 to 3 parts by weight.
• processing aids (D) in an amount of 0.5-5 parts by weight, preferably 0.5 to 3 parts by weight.
• auxiliary fuels (E) can optionally in an amount of 0.5 -20 parts by weight, preferably 0.5-10 parts by weight and in particular 0.5-5 parts by weight steep incline
• fillers (F) may optionally be present in a proportion of 0.5-12 parts by weight, preferably 0.5-10 parts by weight and in particular 0.5-5 parts by weight
• the early spring powders according to the invention for thermal safeguards are not only limited to the airbag field, but can also be used for triggering mechanical movements as well as in pressure and security elements
• the toxicity of the raw materials used for the thermal safeguards according to the invention all correspond to Swiss toxicity classes 3, 4 and 5. Due to the reaction products of these mixtures, due to the previous raw material balance and the small amount used, there is no risk or danger to humans / vehicle occupants. The unused mixtures are easy to dispose of or recycle using conventional means.
• the thermal fuses according to the invention are well contracted with other gas-generating mixtures or pyrotechnic compounds, for example boron / calcium nitrate, and can be mixed in as granules or tablets or in a container preferably made of aluminum (or steel)
• the purity and grain size of these raw materials as well as the various mixtures of oxidizing agents and fuels used influence the temperature and type of decomposition
• the type of stabilizer and its proportion of the mixture has an effect on the long-term stability and the temperature of the drawing
• Thiohamstoff in the new combination with the above-mentioned oxidizing agent (B) and the suitable stabilizers (C) (protective colloids) are systems that react suddenly and strongly exothermic between 150-200 ° C, but on the other hand storage for 400 hours at 107 ° C with a weight loss ⁇ 3% with full function maintenance 0
• the dosing temperature of the chemical fuse can be shifted by adding nitrates and / or perchlorates (see Examples 3 and 5, Table I).
• auxiliary fuels such as metal powders of aluminum, zirconium, titanium, magnesium, zinc, iron, etc.
• the generation of hot particles can be positively influenced.Another way of producing hot particles - but at the expense of the total energy of the thermal fuse mixtures goes through
• the specified mixing ratios premixed in a vertical mixer and by means of water and / or solvents such as C1-C4 alcohols, for example methanol, ethanol, propanol and acetone (Example 10)
• a ready-to-use granulate or a tableting granulate can be used
• Example 7 10 parts by weight parts by weight, parts by weight ⁇
• Example 1 Comparative
• Examples 2 to 5 and 7 to 10 Comparative
• the composition according to Example 1 already showed a weight loss of 216 hours
• the compositions according to the invention meet the stability requirements and after 400 hours only showed a weight loss of between 1.3 and 2.3% and 2.4%, respectively.
• the ignition (or decomposition) temperatures of the early spring powders according to the invention are in the required range of 150-200 ° C. both before and after the thermal stress
• the ignition powders according to the invention according to Examples 2-5 and 7-10 showed a change in the decomposition temperature between 0 and 12 ° C after 400 hours at 107 ° C.
• Decomposition point was determined using differential scanning calorimetry (DSC method) 8 determined The bandwidth in the decomposition temperature determination was ⁇ 5 ° C. at the heating rate of 10 ° C./min
• Example 6 is carried out according to Examples 1-5, instead of thiourea, N, N'-diphenylthiourea is used

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Air Bags (AREA)
• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1998
  • 1998-02-13 DE DE19805976A patent/DE19805976C1/de not_active Expired - Fee Related
• 1999
  • 1999-02-11 AT AT99913070T patent/ATE216985T1/de not_active IP Right Cessation
  • 1999-02-11 DE DE59901347T patent/DE59901347D1/de not_active Expired - Fee Related
  • 1999-02-11 EP EP99913070A patent/EP1054849B1/fr not_active Expired - Lifetime
  • 1999-02-11 KR KR1020007008625A patent/KR20010040741A/ko active IP Right Grant
  • 1999-02-11 AU AU31366/99A patent/AU3136699A/en not_active Abandoned
  • 1999-02-11 WO PCT/DE1999/000414 patent/WO1999041213A1/fr active IP Right Grant
  • 1999-02-11 JP JP2000531413A patent/JP2002503624A/ja active Pending
  • 1999-02-11 CZ CZ20002897A patent/CZ292350B6/cs not_active IP Right Cessation

Non-Patent Citations (1)

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