Compositions – Compositions containing a single chemical reactant or plural... – Organic reactant
Reexamination Certificate
2001-03-16
2002-07-09
Gorr, Rachel (Department: 1711)
Compositions
Compositions containing a single chemical reactant or plural...
Organic reactant
C560S025000, C560S026000, C560S027000, C560S032000, C560S115000, C560S158000, C528S085000
Reexamination Certificate
active
06416686
ABSTRACT:
The present invention relates to polyisocyanates based on two different diisocyanates or polyisocyanates and to a process for preparing them.
In industry, polyisocyanates can generally be advantageously used, inter alia, as building blocks for polyurethane production, e.g. for producing paints and varnishes, coatings, adhesives, sealants, pourable elastomers or foams.
Polyisocyanates based on different diisocyanates or diisocyanates and polyisocyanates can be used particularly advantageously for the abovementioned purposes, but their commercial availability is limited.
Thus, EP-A-755 954 describes the cotrimerization of tolylene diisocyanate (TDI) and hexamethylene diisocyanate (HDI) so as to obtain a polyisocyanate mixture containing isocyanurate groups for the production of polyurethane coating compositions. This product is meant to combine the positive properties of the two isocyanates in PU coating systems, high reactivity and hardness of the aromatic isocyanate and the light stability and resistance to chemicals of the aliphatic isocyanate. However, owing to the large reactivity differences between the aromatically bound and aliphatically bound NCO groups of the starting materials, this reaction gives a very nonuniform product mixture which comprises mainly the homotrimers of tolylene diisocyanate and of hexamethylene diisocyanate and only small proportions of the cotrimers. The reaction is continued to only a partial conversion and unreacted diisocyanates are subsequently removed from the reaction mixture by distillation under reduced pressure.
EP-A-47452 describes the cotrimerization of hexamethylene diisocyanate and isophorone diisocyanate (IPDI). Since the reactivities of the NCO groups of HDI and IPDI are not very different, the cotrimerization is successful here but gives an oligomer mixture having a random HDI/IPDI product distribution. Hereto, unreacted diisocyanate is removed from the reaction mixture by vacuum distillation after the reaction.
It is an object of the present invention to provide polyisocyanates which, owing to their defined structure, combine advantageous properties such as high reactivity, low viscosity and good solubility and can be prepared by simple means, i.e. if possible without work-up by distillation. A further object is to provide a process for preparing these polyisocyanates.
We have found that these objects are achieved by reacting an addition product (A) and/or a polyaddition product (P) which is obtainable by reacting a diisocyanate I with a compound which is reactive toward isocyanate and has one group which is reactive toward isocyanate and one isocyanate group with a diisocyanate or polyisocyanate II which is different from diisocyanate I.
The invention accordingly provides a process for preparing polyisocyanates, which comprises
(i) preparation of an addition product (A) which contains one group which is reactive toward isocyanate and one isocyanate group by reacting
(a) a diisocyanate I with
(b) compounds containing two groups which are reactive toward isocyanate, where at least one of the components (a) or (b) has functional groups having differing reactivities toward the functional groups of the other component,
(ii) if desired, intermolecular addition reaction of the addition product (A) to form a polyaddition product (P) which contains one group which is reactive toward isocyanate and one isocyanate group and
(iii) reaction of the addition product (A) and/or the polyaddition product (P) with a diisocyanate or polyisocyanate II which is different from diisocyanate I.
The invention further provides the polyisocyanates prepared by this process.
The invention also provides for the use of the polyisocyanates of the present invention as building blocks for producing paints and varnishes, coatings, adhesives, sealants, pourable elastomers or foams and provides polyaddition products obtainable using the polyisocyanates of the present invention.
Possible diisocyanates I are the aliphatic, cycloaliphatic and aromatic isocyanates known from the prior art. Preferred diisocyanates I are diphenylmethane 4,4′-diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane 4,4′-diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, dodecyl diisocyanate, 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane, lysine alkyl ester diisocyanate, where alkyl is C
1
-C
10
-alkyl, 2,2,4- or 2,4,4-trimethylhexamethylene 1,6-diisocyanate and 1,4-diisocyanatocyclohexane.
Particular preference is given to diisocyanates having NCO groups of differing reactivity, for example tolylene 2,4-diisocyanate (2,4-TDI), diphenylmethane 2,4′-diisocyanate (2,4′-MDI), isophorone diisocyanate (IPDI), 2-butyl-2-ethylpentamethylene diisocyanate, 2-isocyanatopropylcyclohexyl isocyanate, 3(4)-isocyanatomethyl-1-methylcyclohexyl isocyanate, 1,4-diisocyanato-4-methylpentane, dicyclohexylmethane 2,4′-diisocyanate and 4-methylcyclohexane 1,3-diisocyanate (H-TDI).
Particular preference is also given to diisocyanates whose NCO groups initially have the same reactivity but in which addition of an alcohol or amine to a first NCO group induces a decrease in the reactivity of the second NCO group. Examples are isocyanates whose NCO groups are coupled via a delocalized electron system, e.g. phenylene 1,3- and 1,4-diisocyanate, naphthylene 1,5-diisocyanate, biphenyl diisocyanate, tolidine diisocyanate or tolylene 2,6-diisocyanate.
Possible diisocyanates and polyisocyanates II are all aliphatic, cycloaliphatic and aromatic isocyanates known from the prior art. Apart from the abovementioned diisocyanates and polyisocyanates, it is also possible to use, for example, oligoisocyanates or polyisocyanates which can be prepared from the abovementioned diisocyanates or mixtures thereof by coupling by means of urethane, allophanate, ureas, biuret, uretdione, amide, isocyanurate, carbodiimide, uretonimine, oxadiazinetrione or iminooxadiazinedione structures.
As diisocyanates and polyisocyanates II, particular preference is given to using diphenylmethane 4,4′-diisocyanate, mixtures of diphenylmethane diisocyanates and oligomeric diphenylmethane diisocyanates (polymeric MDI), phenylene 1,3- and 1,4-diisocyanate, isophorone diisocyanate, oligomers of isophorone diisocyanate containing isocyanurate, uretdione, urethane or allophanate groups, hexamethylene diisocyanate, oligomers of hexamethylene diisocyanate containing isocyanurate, uretdione, urethane, allophanate, iminooxadiazinedione or biuret groups, 4-isocyanatomethyloctamethylene 1,8-diisocyanate, oligomers of MDI containing urethane, allophanate, carbodiimide or uretonimine groups or oligomers of TDI containing urethane, allophanate, carbodiimide or uretonimine groups.
In general, the diisocyanates and polyisocyanates II used have a mean functionality of at least 2, in particular from 2 to 8. In a preferred embodiment, the diisocyanates or polyisocyanates II used are isocyanates having a mean functionality of more than 2, preferably from 2.1 to 5.
Both for the diisocyanates I and for the diisocyanates and polyisocyanates II, it is also possible to use mixtures of the isocyanates mentioned.
The compounds (b) having two isocyanate-reactive groups which are used in the preparation of the addition product (A) are selected from among compounds containing hydroxyl groups, mercapto groups or amino groups. Preference is given to hydroxyl groups and amino groups.
In the preparation of the addition product (A), it is likewise possible to use compounds (b) having two isocyanate-reactive groups selected from among the abovementioned functional groups or mixtures thereof and having differing reactivities toward NCO groups. Preference is here given to compounds having one primary and one secondary or tertiary hydroxyl group, one hydroxyl group and one mercapto group or one hydroxyl group and one amino group in the molecule, since the reactivity of the amino group in the reaction with isocyanate is significantly higher than that of the hydroxyl group.
Preference is also given to isocyan
Bruchmann Bernd
Ehe Ulrike
Königer Rainer
Müller-Mall Rudolf
Renz Hans
BASF - Aktiengesellschaft
Borrego Fernando A.
Gorr Rachel
LandOfFree
Polyisocyanates does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polyisocyanates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polyisocyanates will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2865748