Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Patent
1996-05-15
1998-04-07
Cooney, Jr., John M.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
521107, 521108, 5211091, 521128, 521130, 521131, 521163, 521168, 521170, 521172, 521174, C08J 914
Patent
active
057365881
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to rigid foams which possess urethane groups and which are prepared without the use of chlorofluorohydrocarbons.
BACKGROUND OF THE INVENTION
Due to their outstanding thermal insulation properties, closed-cell polyurethane rigid foams have been used for many years for insulating cooling and freezing appliances, industrial plant, tank stores, piping, in ship-building and for numerous insulation applications in the building industry.
The thermal conductivity of polyurethane rigid foam which has largely closed cells is dependent to a large extent on the type of blowing agent or cell gas. Perhalogenated chlorofluorohydrocarbons (HCFCs) have proven particularly suitable for this purpose, especially trichloromethane (R11) which has a particularly low thermal conductivity. These substances are chemically inert, and thus non-toxic and non-flammable. Perhalogenated chlorofluorohydrocarbons, however, reach the stratosphere, due to their high stability, where, due to their chlorine content, they will contribute to degradation of the ozone which is present (e.g. Mario J. Molina und F. S. Rowland, Nature 249 (1974) p. 810 and first interim report from the Bundestag-Enquete-Kommission "Vorsorge zum Schutz der Erdatmosphare" (Provisions for protecting the Earth's atmosphere) dated Feb. 11, 1988, Deutscher Bundestag, Referat Offentlichkeitsarbeit, Bonn).
It was therefore proposed that unsubstituted hydrocarbons (alkanes) be used as blowing agents for foams, including polyurethane foams, instead of perhalogenated chlorofluorohydrocarbons.
Alkanes do not contain chlorine atoms and thus have an ODP (Ozone Depletion Potential) of zero (for comparison: R11 has an ODP of 1).
A typical representative of alkanes as blowing agents, apart from isopentane and n-pentane, is cyclopentane.
Hydrocarbons are highly non-polar, due to their chemical structure, and therefore do not mix well with the polyols and isocyanates used for producing rigid foams. However, this is an important prerequisite for conventional methods of production, in which the polyol and isocyanate components are mechanically mixed with each other.
The polyol component contains, in addition to the reactive polyether or polyester-polyols, also the blowing agent and auxiliary substances such as activators, emulsifiers and stabilisers in dissolved form. Thus, as far as the polyol component is concerned, a single-phase mixture is present.
The low solubility of hydrocarbons, when a conventional blowing agent, such as e.g. R11, is exchanged on an equimolar basis for environmentally friendly compounds (alkanes) in commercial formulations, frequently leads to the formation of two phases which can no longer be conventionally processed.
SUMMARY OF THE INVENTION
Thus the object of the invention was to increase the solubility of hydrocarbons in polyols, so that when e.g. R11 is replaced by equimolar amounts of these hydrocarbons, a single-phase polyol component is obtained.
Surprisingly, it was found that the solubility of hydrocarbons in polyols can be considerably increased when specific solution promoters, which are described in more detail below, are added.
The invention provides a method for preparing rigid foams which contain urethane groups by reacting reactive towards isocyanate groups, with a molecular weight of 92 to 10,000, in the presence of one compound with a polar group, selected from the group consisting of: atoms or together form an alkylene group with 2 to 6 carbon atoms, ##STR1## wherein R.sup.3 and R.sup.4 represent alkyl groups with 1 to 12 carbon atoms and n is a number from 0 to 6, ##STR2## wherein R.sup.5 to R.sup.7 represent an optionally halogen-substituted alkyl group with 1 to 12 carbon atoms, a cycloalkyl group with 5 to 10 carbon atoms or an aryl group with 6 to 12 carbon atoms, consisting of at least one optionally unsaturated fatty acid with 15 to 25 carbon atoms and (ii) one mole of a diamine component consisting of at least one diamine of the formula ##STR3## where n=2 to 10, and atoms and X.sup.-
REFERENCES:
patent: 5223546 (1993-06-01), Morita et al.
patent: 5244931 (1993-09-01), Kuyzin
Database WPI, Derwent Publications Ltd. London, GB; AN 92-345080!42! and JP, A, 4 249 513 (Mitsui Toatsu Chem Inc.) Sep. 4, 1992. (Abstract).
Mario J. Molina & F.S. Rowland, Nature vol. 249 (1974) p. 810.
Eisen Norbert
Klan Walter
Otto Frank
Thompson-Colon James
Bayer Aktiengesellschaft
Cheung Noland J.
Cooney Jr. John M.
Gil Joseph C.
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