Organic compounds -- part of the class 532-570 series – Organic compounds – Isocyanate esters
Reexamination Certificate
1999-01-21
2001-08-14
Cooney, Jr., John M. (Department: 1711)
Organic compounds -- part of the class 532-570 series
Organic compounds
Isocyanate esters
C528S045000, C560S336000
Reexamination Certificate
active
06274759
ABSTRACT:
The present invention relates to diisocyanates containing hydantoin groups, a process for their preparation, polyurethanes in which diisocyanates containing hydantoin groups are present and the use of these polyurethanes for producing fibers, films, foams, molding compositions, coatings and surface coating compositions as well as fibers, films, foams, molding compositions, coatings and surface coating compositions comprising such a polyurethane.
Polyurethanes are formed by reaction of polyisocyanates with polyols. Owing to the wide variety of possible reactions of the isocyanate group and its high reactivity, the polyisocyanates are used for producing foams, fibers, films, surface coating compositions and paints. For example, rigid polyurethane foams can be used for filling hollow spaces of refrigeration appliances or heating elements with foam since they have a low thermal conductivity. Selection of the raw materials enables the properties of the rigid foams to be varied within a wide range.
A summary overview of polyurethanes, their preparation and their use is described in Becker/Braun, Kunststoff Handbuch, Volume 7, Polyurethane, 3rd edition, 1993, Carl Hanser Verlag.
EP-A 0 744 419, 0 744 424, 0 744 425 and 0 744 427 disclose a process for synthesizing hydantoin-containing polyurethane prepolymers. All these processes have in common the fact that the hydantoin groups are formed in the prepolymer by a ring-closing condensation reaction which occurs at elevated temperatures. Furthermore, in this process, the hydantoin groups are only formed on prepolymers whose isocyanate groups are blocked by means of a protective group.
The protective group technique disclosed in these publications is disadvantageous, since it requires additional synthetic steps on the route to the finished polyurethane.
It is an object of the present invention to provide a process for synthesizing prepolymers and polyurethanes containing hydantoin groups and also corresponding prepolymers and polyurethanes, where the synthetic step for introducing and removing appropriate protective groups can be dispensed with. It is a further object of the present invention to provide a process for synthesizing prepolymers and polyurethanes containing hydantoin groups, in which process the prepolymer or polyurethane containing hydantoin groups is formed and a flame retardant is simultaneously formed, and also to provide the corresponding prepolymers and polyurethanes.
We have found that this object is achieved by a diisocyanate of the formula (I)
where R
1
is a C
1
-C
10
-hydrocarbon radical and R
3
is a C
1
-C
12
-hydrocarbon group and n is an integer from 1 to 10.
R
1
is preferably a C
1
-C
6
-alkyl radical, in particular a methyl, ethyl, propyl or butyl radical, or an aryl radical, particularly preferably a phenyl radical. R
3
is preferably an alkylene group having from 3 to 12 carbon atoms, a cycloalkylene group having from 3 to 12 carbon atoms or an arylene group having from 7 to 12 carbon atoms, in particular an unbranched alkylene group having from 4 to 8 carbon atoms, particularly preferably 6 carbon atoms, which at the ends is located next to the isocyanate group.
The object is also achieved by a process for preparing diisocyanates, in particular of the formula (I), in which phospholenes of the formula (II), where R
1
is as defined above and R
2
is a C
1
-C
10
-hydrocarbon group, are reacted with diisocyanates of the formula (III), where R
3
is as defined above, forming a phosphate of the formula (IV).
Here, R
1
and R
2
can be identical or different.
Furthermore, it has surprisingly been found that both the diisocyanates of the formula (I) containing hydantoin groups and the polyurethanes obtained therefrom are significantly more thermally stable than the hydantoin-containing diisocyanates and polyurethanes described in the prior art.
As organic diisocyanates of the formula (III), it is possible to use all known suitable aliphatic, cycloaliphatic and aromatic compounds having more than one isocyanate group. Preferred organic diisocyanates are straight-chain or branched alkylene diisocyanates having from 1 to 12 carbon atoms, e.g. dodecane 1,12-diisocyanate, 2-ethylbutylene 1,4-diisocyanate, 2-methylpentylene 1,5-diisocyanate, butylene 1,4-diisocyanate, hexamethylene 1,6-diisocyanate (HDI); cycloaliphatic diisocyanates having from 3 to 12 carbon atoms, e.g. cyclohexyl 1,3-diisocyanate, cyclohexyl 1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-iso-cyanatomethylcyclohexane (IPDI), hexahydrotolylene 2,4- and 2,6-diisocyanate and the corresponding isomer mixtures, dicyclohexylmethane 4,4′- , 2,2′- and 2,4′-diisocyanate and also the corresponding isomers mixtures and aromatic diisocyanates having from 7 to 12 carbon atoms, e.g. tolylene 2,4- and 2,6-diisocyanate (TDI) and their isomer mixtures, diphenylmethane 4,4′-, 2,2′- and 2,4′-diisocyanate (MDI) and also their isomer mixtures, mixtures of diphenylmethane 4,4′-, 2,2′-diisocyanates, polyphenylpolymethylene polyisocyanates (polymeric MDI), mixtures of diphenylmethane 4,4′-, 2,2′- and 2,4′-diisocyanates and polyphenylpolymethylene polyisocyanates (crude MDI) and mixtures of crude MDI and tolylene diisocyanates. Preference is given to using hexamethylene 1,6-diisocyanate (HDI), tolylene 2,4- and 2,6-diisocyanate (TDI) and their isomer mixtures, mixtures of diphenylmethane 4,4′-, 2,2′-diisocyanates (MDI) and polyphenylpolymethylene polyisocyanates (polymeric MDI).
In a further embodiment of the process of the present invention, the phosphate of the formula (IV) formed in the reaction is removed at least partially, preferably completely, from the reaction mixture.
Furthermore, in the reaction of the phospholenes of the formula (II) with the diisocyanates of the formula (III) in the process of the present invention, the diisocyanates of the formula (III) are preferably used in excess, particularly preferably at least in a two-fold excess.
This reaction forms a composition which comprises at least one diisocyanate of the formula (I), a diisocyanate of the formula (III) and possibly a phosphate of the formula (IV).
The amount of the flame-retardant phosphate of the formula (IV) present in the composition depends on the extent to which the phosphate of the formula (IV) has, as described above, been removed from the composition; the flame-retardant effect of the phosphate of the formula (IV) increases as the proportion present in the composition rises.
The proportion of the flame-retardant phosphate of the formula (IV) in the overall composition is selected such that the amount of phosphate of the formula (IV) present in the polyurethane formed as end product is sufficient to ensure a satisfactory flame-retardant effect.
The proportion of the phosphate of the formula (I) is from 0.1 to 25% by weight, preferably from 0.5 to 7% by weight, based on the total polyurethane and particularly preferably based on the A component of the polyurethane.
In addition, the viscosity of the composition can be controlled via the proportion of the phosphate of the formula (IV).
In a preferred embodiment of the invention, the ratios of (a) to (b) and to the diisocyanate of the formula (I) are from 1:1:1 to 6:1:1 and preferably from 1:1:1 to 4:1:1.
According to the present invention, particular preference is given to varying the viscosity of the not yet cured polyurethane or the polyurethane component by means of the phosphate of the formula (IV). This is particularly advantageous when the polyurethane is used for filling, preferably filling with foam, shapes having a complicated structure. The control of the viscosity in the direction of easy-flowing liquids is achieved by increasing the proportion of the phosphate of the formula (IV) in the not yet polymerized polyurethane or in the polyurethane components.
In a preferred embodiment, the proportion of the phosphate of the formula (IV) in all components used except for component (a) is from 0.5 to 30% by weight, preferably from 3 to 20% by weight.
The
Graf Hermann
Mohrhardt Gunter
Rotermund Udo
BASF - Aktiengesellschaft
Borrego Fernando A.
Cooney Jr. John M.
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