Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/20—Carboxylic acid amides

Definitions

• the present invention relates to production processes where a pre ⁇ polymer is cured and particularly to a method of avoiding in such processes a too rapid curing reaction, which gives an extension of the so-called pot life.
• Solid propellants so-called composite propellants, for use for in ⁇ stance in rocket and missile propellant charges are pyrotechnical compositions mixed with for instance a ther osetting resin.
• a liquid prepolymer e.g. hydroxy terminated poLybutadiene (HTPB) or carboxy terminated poLybutadiene (CTPB), which comprises chemicaLly reactive groups and which, after various additions, is crosslinked and cured by means of a curing agent.
• HTPB hydroxy terminated poLybutadiene
• CTPB carboxy terminated poLybutadiene
• metal comprising additives e.g. combustion catalysts such as iron oxide and ferro- cene compounds.
• transition metals e.g. iron and copper
• transition metals e.g. iron and copper
• the metal comprising additives that are added for instance to catalyze the combustion of the produced propellant have because of this as a side-effect that they might heavily shorten the pot life, sometimes so heavily that a production in larger scale turns out to be impossible.
• the present invention relates to a method that will eliminate said difficulty.
• the characteristics of the invention are evident from the subsequent patent claims.
• each of 1 and f- is hydrogen or a hydrocarbon group, for instance a tetracycline compound, to form complexes with the transi ⁇ tion metals that are present in the mixture.
• Very small amounts of the metal complex forming component are re ⁇ quired. Suitably there is added between 0 and 3 weight percent based on the produced propellant. Preferably there are used so small amounts as 0.05-1 weight percent.
• Certain types of solid propellants comprise metals, e.g. magnesium or aluminium, to increase the energy content.
• metals e.g. magnesium or aluminium
• this will also cause a heavy intensification of the activity of the combustion catalysts as curing catalysts, causing difficulties in the production.
• the method according to the invention has a favourab ⁇ le effect. It removes the negative influence of the metal on the curing course of reaction, and long pot lifes will again be obtained.
• the invention is generally applicable in production processes, where a prepolymer is being cured and where there is a wish to remove the undesirable catalytic action of the transition metals present on the curing reaction, for instance in the production of plastic-bound explosives or other types of encapsulation in plastic.
• the method of the invention is also applicable in all polyurethane
• Such undesirable metal catalysis of the curing reaction is preven ⁇ ted according to the invention by adding before the curing a small amount of a compound, whose structural formula comprises the metal- binding part
• each of R,. and. R ⁇ is hydrogen or a hydrocarbon group.
• Tetracycline is an example of such a compound that is useful in the method according to the invention to form complexes with transition metals present.
• Tetracycline being a wellknown antibiotic, belongs to a group of structualLy similar, biologically active compounds. Their chemical structure is
• R- and R 2 are hydrogen or a hydrocarbon group
• Rj is hydrogen or hydroxy
• R is hydrogen or hydroxy
• R ⁇ is hydrogen or lower alkyl or R
• R-. together is CH 2
• Examples of other compounds of the group are 7-chlorotetracycline and 5-hydroxytetracycline.
• the other tetracyclines can also be used in the method of the inven ⁇ tion, for instance
• HCL-analoges of tetracyclines The structure is such that there are good possibilities for metal complex formation, and the antibiotic activities of the compounds are considered to depend on their metal binding ability.
• Tetracycline is common, is easy to get to a moderate price and is very attractive from an occupational hygienic point of view in con ⁇ trast to those substances that have been used previously to extend the so-called pot life.
• Another example of a compound that is useful in the method of the invention is 2-hydroxy-4-methyl-6-ketocyclohexenyl ⁇ carboxamide with the formula
• the propellant composition comprised hydroxy terminated poLybutadiene (HTPB) of the type ARCO R-45HT, 100 parts, isophorone diisocyanate (IPDI), 10 parts, and ammonium perchlorate up to 85 % of the total 15 amount.
• HTPB hydroxy terminated poLybutadiene
• IPDI isophorone diisocyanate
• ammonium perchlorate up to 85 % of the total 15 amount.
• various additives were part of the composition in amounts that are given in the table, where pph is parts per 100 parts of HTPB. Given percentages are weight percent of the total amount.
• Plastic binder (R-45HT + DDI ) 30.0 29.9 29.4 Polystyrene granules 70.0 70.0 70.0 Iron octoate 0.1 0.1 Tetracycline 0.5
• the polystyrene is completely neutral as to the curing reaction and may be replaced with any other filler that is neither taking part in the curing processes. AIL the samples could be heat-treated (+70 C) into well-cured samples after the plastograph runnings.
• the plastograph experiment was also carried out with HTPB-based propellant compositions that comprised a copper compound instead of an iron compound.
• Binder HTPB of the type R-45HT 100 parts Temp +58°C BKF 2 DDI 24 "
• CTPB Carboxy terminated poLybutadiene
• MAPO three-valent aziridine
• Cr-DIPS chro ⁇ mium diisopropylsalicylate
• CTPB of the type HC-434 was used ⁇ and as epoxide there was used a standard product from Shel l, Epi kote 828. As fi l ler there were used sma l l polystyrene granua les (PS) . The compositions were run in the plastograph at 58° C as previous ly described.
• composition Composition, weight percent Sylgard 182 94 parts 30 28 27.8 Curing agent 6 parts Tertiary pentylferrocene ( ⁇ TPF) - 2 2 2 Magnesium powder 50 50 50 Ammonium perchlorate (15 urn) 20 20 20 Tetracycline 0.2
• the samples could be cured into a crosslinked rubber material at an enhanced temperature. From the table there is evident, that the presence of ferrocene makes the composition cure more rapidly and that an addition of tetracycline will again extend the pot life.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Polyurethanes Or Polyureas (AREA)
• Dental Preparations (AREA)
• Tires In General (AREA)
• Cosmetics (AREA)

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Publications (1)

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• 1981
  • 1981-12-22 SE SE8107725A patent/SE447390B/sv not_active IP Right Cessation
• 1982
  • 1982-12-22 WO PCT/SE1982/000437 patent/WO1983002282A1/en active IP Right Grant
  • 1982-12-22 US US06/527,517 patent/US4493916A/en not_active Expired - Fee Related
  • 1982-12-22 EP EP83900204A patent/EP0096700B1/en not_active Expired
  • 1982-12-22 JP JP83500294A patent/JPS58502215A/ja active Pending
  • 1982-12-22 DE DE8383900204T patent/DE3265304D1/de not_active Expired
• 1983
  • 1983-08-19 NO NO83832986A patent/NO158682C/no unknown

Non-Patent Citations (1)

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