Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Patent
1996-07-03
1997-11-18
Foelak, Morton
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
521116, 521159, 528 49, 528 59, 528 85, 560330, G08G 1810
Patent
active
056889895
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to new polyurethane compositions modified with hydrophilic surfactants containing isocyanate-reactive functional groups for the production of fine-cell homogeneous polyurethane foams.
DISCUSSION OF RELATED ART
Prior Art
Polyurethane foams, more especially so-called one-component polyurethane foams, are known for example from Ullmanns Enzyklopadie der technischen Chemie, 4th Edition, Vol. 19, pages 317 et seq., Verlag Chemie, Weinheim. The foams in question are mixtures of isocyanate-terminated reaction products of polyols with difunctional or polyfunctional isocyanates, catalysts to accelerate the reaction, viscosity-reducing agents, blowing agents and other auxiliaries which--protected against moisture--are marketed in pressurized containers. When they are released from the pressurized containers, the mixtures foam through evaporation of the blowing agent and cure under the effect of moisture from the surrounding environment or from the atmosphere. Polyurethane foams are used, for example, for insulating domestic appliances, as an insulating material and for filling joints with foam in the building industry and as insulating materials.
They essentially contain polyols bearing several OH groups in the molecule, difunctional or polyfunctional isocyanates, blowing agents, flame-proofing agents and auxiliaries, such as catalysts and stabilizers.
The polyols used may be any of the polyether or polyester polyols typically used in polyurethane chemistry. A review of possible polyols can be found in Ullmanns Enzyklopadie der technischen Chemie, 4th Edition, Vol. 19, pages 304-5, Verlag Chemie, Weinheim. The production of inexpensive oleochemical polyols from renewable raw materials and their use for this purpose is also known, cf. German patent applications DE-A1 36 26 223 and DE-A1 41 28 649. The first application claims prepolymers based on oleochemical polyols which are obtained by ring opening of epoxidized triglycerides with alcohols and subsequent partial transesterification. The second application describes the lithium-salt-catalyzed ring opening of epoxides with nucleophiles, such as alcohols, optionally in conjunction with subsequent transesterification of the reaction products with other non-epoxidized triglycerides.
Hitherto, chlorofluorocarbons (CFC's) have often been used as blowing agents. On account of ecological objections to these compounds which damage the ozone layer, so-called partly halogenated hydrocarbons (HCFC's) which are less damaging to the ozone layer, for example difluorochloromethane, difluorochloroethane, dichlorofluoroethane or tetrafluoroethane, have recently been used to an increasing extent as blowing agents. It is also known that fluorine-containing blowing agents need not be used at all, being replaced for example by dimethyl ether, propane or isobutane.
The use of more highly fluorinated or CFC-free blowing agents or oleochemical polyols, which is actually desirable from the ecological point of view, results in hydrophobicization of the polyurethane compositions. As a result, the water which is absolutely essential for the crosslinking and curing of the polyurethane compositions to form foams is unable adequately to penetrate through the foam. This results in the formation of voids in the foam and in unwanted shrinkage of the foam after setting. To avoid this, both the substrate and the foam itself have to be thoroughly moistened during processing of the foams. Voids occur in greater numbers when the polyurethane foams are applied to dry substrates.
The formation of voids and shrinkage are technically undesirable and complicate or prevent application of the ecologically more favorable polyurethane foams.
Accordingly, the problem addressed by the present invention was to provide polyurethane foams, more especially based on oleochemical polyols and/or free from CFC-containing blowing agents, which would give fine-cell, homogeneous and substantially void-free foams without moistening of the subst
REFERENCES:
patent: 3463745 (1969-08-01), Hofrichter et al.
patent: 3865762 (1975-02-01), Replquet et al.
patent: 4508853 (1985-04-01), Kluth et al.
patent: 4742087 (1988-05-01), Kluth et al.
Ullmanns Enzyklopadie der technischen Chemie, 4th Edition, vol. 19, p. 317 et seq., Verlag Chemie, Weinheim, 1980.
Ullmanns Enzyklopadie der technischen Chemie, 4th Edition, vol. 19, pp. 304-305, Verlag Chemie, Weinheim, 1980.
Ullmanns Enzyklopadie der technischen Chemie, 4th Edition, vol. 19, pp. 303 to 304, Verlag Chemie, Weinheim, 1980.
Daute Peter
Gruetzmacher Roland
Hoefer Rainer
Klein Johann
Kluth Hermann
Foelak Morton
Grandmaison Real J.
Henkel Kommanditgesellschaft auf Aktien
Jaeschke Wayne C.
Szoke Ernest G.
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