The invention relates to a process for preparing liquid, storage-stable isocyanate mixtures having carbodiimide (CD) and/or uretonimine (UI) groups or prepolymers derived therefrom, wherein (i) in a first step, a starting isocyanate which is an organic isocyanate or a mixture of two or more organic isocyanates is partly carbodiimidized with a catalyst K of the formula cyclo-C.sub.4H.sub.6P(O)R, where the substituent R is a saturated or unsaturated, optionally substituted, especially halogen-substituted, organic radical, and then (ii) in a second step, the carbodiimidization reaction is stopped at a temperature of 80 C. by adding a stopper, the stopper used being an organic silane S of the general formula H.sub.nSiX.sub.4-n, where n is a natural number in the range from 1 to 3, where X is a saturated or unsaturated, optionally substituted, especially halogen-substituted, organic radical.

The invention relates to a process for preparing liquid, storage-stable isocyanate mixtures having carbodiimide (CD) and/or uretonimine (UI) groups or prepolymers derived therefrom, wherein (i) in a first step, a starting isocyanate which is an organic isocyanate or a mixture of two or more organic isocyanates is partly carbodiimidized with a catalyst K of the formula cyclo-C.sub.4H.sub.6P(O)R, where the substituent R is a saturated or unsaturated, optionally substituted, especially halogen-substituted, organic radical, and then (ii) in a second step, the carbodiimidization reaction is stopped at a temperature of 80 C. by adding a stopper, the stopper used being an organic silane S of the general formula H.sub.nSiX.sub.4-n, where n is a natural number in the range from 1 to 3, where X is a saturated or unsaturated, optionally substituted, especially halogen-substituted, organic radical.

An isocyanate composition according to the present invention contains an isocyanate compound of formula (1) and/or (2) (wherein R.sup.1 represents a hydrogen or a monovalent organic group, and R.sup.2 represents a monovalent organic group), and, relative to the total mass of the isocyanate compound in the composition, 1.0 ppm by mass to 10% by mass of a compound of formula (3): R.sup.13(COOR.sup.14)a (wherein R.sup.13 represents an organic group with a valence of a, R.sup.14 represents a monovalent organic group, and a represents an integer of 1 or 2), which is different from the isocyanate compound, and/or, 1.0 ppm by mass to 10% by mass of a compound having an UV absorption in an area of decamer or higher isocyanates in a measurement spectrum of gel permeation chromatography.

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The present invention provides an isocyanate composition including an isocyanate compound having an ethylenically unsaturated bond, a compound represented by formula (1) (in the formula, R.sup.1 represents an a-valent organic group, R.sup.2 represents a monovalent organic group, a represents an integer of 1 or 2), and/or a compound having a UV absorption in a spectral region of a decamer or higher isocyanate measured by gel permeation chromatography; and an isocyanate composition including an isocyanate compound having an ethylenically unsaturated bond, or a compound having at least one unsaturated bond other than an unsaturated bond constituting an aromatic ring or an inert compound such as a hydrocarbon compound or the like and having a carbon-carbon unsaturated bond other than an unsaturated bond constituting an aromatic ring; or the like.

The present invention provides an isocyanate composition including an isocyanate compound having an ethylenically unsaturated bond, a compound represented by formula (1) (in the formula, R.sup.1 represents an a-valent organic group, R.sup.2 represents a monovalent organic group, a represents an integer of 1 or 2), and/or a compound having a UV absorption in a spectral region of a decamer or higher isocyanate measured by gel permeation chromatography; and an isocyanate composition including an isocyanate compound having an ethylenically unsaturated bond, or a compound having at least one unsaturated bond other than an unsaturated bond constituting an aromatic ring or an inert compound such as a hydrocarbon compound or the like and having a carbon-carbon unsaturated bond other than an unsaturated bond constituting an aromatic ring; or the like.

The present invention relates to a method for stably storing an isocyanate composition, the stably stored isocyanate composition, and a polyurethane resin prepared from the isocyanate composition.

The present invention relates to a method for stably storing an isocyanate composition, the stably stored isocyanate composition, and a polyurethane resin prepared from the isocyanate composition.

The present invention relates to a method for stably storing an isocyanate composition, the stably stored isocyanate composition, and a polyurethane resin prepared from the isocyanate composition.

This disclosure relates to a composition comprising (a) 4,4-methylene diphenyl diisocyanate (4,4-MDI), and (b) at least one heterocyclic compound comprising as ring moiety at least one structure of formula (I) as defined in the description. The heterocyclic compound can suppress the formation of 4,4-MDI dimer and thus prevent the formation of insoluble solids and extend the shelf life of 4,4-MDI.

This disclosure relates to a composition comprising (a) 4,4-methylene diphenyl diisocyanate (4,4-MDI), and (b) at least one heterocyclic compound comprising as ring moiety at least one structure of formula (I) as defined in the description. The heterocyclic compound can suppress the formation of 4,4-MDI dimer and thus prevent the formation of insoluble solids and extend the shelf life of 4,4-MDI.