Organic compounds -- part of the class 532-570 series – Organic compounds – Isocyanate esters
Patent
1997-03-20
1998-03-31
Barts, Samuel
Organic compounds -- part of the class 532-570 series
Organic compounds
Isocyanate esters
560347, 528 44, 528 68, C07C24900
Patent
active
057340765
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP95/03260 filed Aug. 16, 1995.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to 4,4'-methylene-bis-(3-chloro-2,6-dialkylphenylisocyanates) of the general formula: ##STR2## in which R.sub.1 means an alkyl group with 1 to 6 C atoms and R.sub.2 means chlorine or an alkyl group with 1 to 6 C atoms, a process for preparing the said polyisocyanates, and the use of the said polyisocyanates in polyurethane (PU) systems.
PU systems are defined below as polyurethane systems that contain urethane groups and/or urea groups.
BACKGROUND ART
Toluene-2,4-diisocyanate and/or toluene-2,6-diisocyanate, abbreviated TDI, or diphenylmethane-4,4'-diisocyanate, abbreviated MDI, continue to be of considerable importance as polyisocyanate components in the production of PU systems.
A major drawback of TDI is its high toxicity. Although the compound is handled on an industrial scale with the most stringent safety precautions possible, it carries a considerable risk potential.
A complete switch to the less toxic MDI is also only conditionally possible since MDI, owing to its high reactivity, can be processed with polyols, but not with aromatic polyamines.
In addition, the PU systems that are based on TDI and MDI are limited, in terms of their temperatures of use, to a maximum of 100.degree. C.
BROAD DESCRIPTION OF THE INVENTION
The object of this invention was consequently to develop polyisocyanates that are not highly toxic, have lower reactivity than MDI, and can be processed with the conventional and new PU processing process. The goal of developing chemically stable PU systems that can be used at temperatures of above 100.degree. C. was associated with the object.
These objects are achieved with the polyisocyanates of the above-mentioned general formula I according to the invention.
R.sub.1 and R.sub.2 mean a C.sub.1 -C.sub.6 -alkyl group which can be the same in meaning or different and may suitably stand for methyl, ethyl, n- or i-propyl, n-, i- or t-butyl, pentyl and its isomers and hexyl and its isomers. R.sub.1 and R.sub.2 are preferably the same in meaning and stand for one of the above-mentioned C.sub.1 -C.sub.4 -alkyl groups.
The preferred polyisocyanate is the 4,4'-methylene-bis-(3-chloro-2,6-diethylphenylisocyanate) with the meaning of R.sub.1 and R.sub.2 are each ethyl.
The production of the polyisocyanates according to the invention is carried out in the known way by reacting the corresponding polyamine with phosgene or a phosgene-releasing compound, such as, di- or triphosgene (cf., e.g., Chemistry!, 4.sup.th Edition, Volume 13, pp. 351 ff).
The corresponding polyamines are described in European Application A 0 220 641. 4,4'-Methylene-bis-(3-chloro-2,6-diethylaniline) (M-CDEA) is the preferred polyamine.
The phosgenation is carried out suitably in the presence of an inert solvent such as, toluene or chlorobenzene at elevated temperature. The reaction generally proceeds virtually quantitatively.
The resulting polyisocyanates have a high purity.
The processing of the polyisocyanates according to the invention into PU systems is carried out basically in a known way by reaction with compounds with at least two hydrogen atoms that are active compared to polyisocyanates and optionally chain-lengthening agents and optionally in the presence of commonly used catalysts and optionally other additives Edition, published in Carl Hauser Verlag, Munich 1989, pp. 429 if).
It is also possible to use mixtures of the polyisocyanates according to the invention with other aliphatic or aromatic polyisocyanates or prepolymers of polyisocyanates or prepolymers that are based on mixtures of polyisocyanates with aliphatic or aromatic polyisocyanates.
Suitable representatives of compounds with at least two hydrogen atoms that are active compared to polyisocyanates are especially polyols, such as, e.g., polyether polyols, polyester polyols, or other polyols, (e.g., polycaprolactones). Suitable representatives of chain-lengthening agents are polyamines, such as, e.g., the
REFERENCES:
patent: 3426025 (1969-02-01), Smeltz et al.
patent: 5028685 (1991-07-01), Ho et al.
Ullmanns Encykl. D. techn. Chemie, 4th Ed., vol. 13, pp. 351 ff. 1977.
Saechtling, Kunststoff Taschenbuch, 24th Ed., published in Carl Hauser Verlag, Munich, (1989), pp. 429 ff.
Daum Ulrich
Hardt Peter
Barts Samuel
Lonza AG
LandOfFree
4,4'-methylene-bis-(3-chloro-2,6-dialkylphenylisocyanates) does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with 4,4'-methylene-bis-(3-chloro-2,6-dialkylphenylisocyanates), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 4,4'-methylene-bis-(3-chloro-2,6-dialkylphenylisocyanates) will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-53597