An object is to provide a method for easily producing maleimide (MI) in which trace amounts of residual acid components as impurities in a crude MI are efficiently reduced, that is, the acid value is sufficiently reduced. <1> A method for producing purified MI, comprising reducing an acid value of crude MI by 50% or more, by adding carbodiimide (CDI) to a solution comprising the crude MI to react an acid component in the crude MI with the CDI. <2> The method for producing purified MI, comprising adding 0.5% by mass or more and 8% by mass or less of the CDI with respect to a mass of the crude MI for reaction. <3> The method for producing purified MI, wherein the CDI is N,N-diisopropyl carbodiimide (DIC). <4> The method for producing purified MI, comprising removing a urea derivative of the CDI (CDI-U) by-produced when reacting the acid component in the crude MI with the CDI.

A method of producing a polycarbodiimide polymer comprises heating a precursor compound at a desired temperature. The method further comprises combining the precursor compound, a diisocyanate compound, and a carbodiimidization catalyst to form a reaction mixture. Finally, the method comprises heating the reaction mixture for a first period of time at a first temperature, thereby reacting the precursor compound and the diisocyanate compound in the presence of the carbodiimidization catalyst to produce the polycarbodiimide polymer.

A method of producing a polycarbodiimide polymer comprises heating a precursor compound at a desired temperature. The method further comprises combining the precursor compound, a diisocyanate compound, and a carbodiimidization catalyst to form a reaction mixture. Finally, the method comprises heating the reaction mixture for a first period of time at a first temperature, thereby reacting the precursor compound and the diisocyanate compound in the presence of the carbodiimidization catalyst to produce the polycarbodiimide polymer.

The present invention is directed to a process for preparing amides or polyamides by replacing isocyanate starting materials of a catalyzed thermal reaction with aromatic carbamates. Through the catalyzed thermal process involving a non-isocyanate precursor of the present invention, efficiency for producing amides or polyamides can be significantly improved, and the impure side products produced from a side reaction of isocyanate can be greatly curtailed. Hence, amides or polyamides of high purity and yield can be achieved. The invention also relates to a process for preparing aromatic carbamates, the new non-isocyanate precursors for amides or polyamides.

The present invention is directed to a process for preparing amides or polyamides by replacing isocyanate starting materials of a catalyzed thermal reaction with aromatic carbamates. Through the catalyzed thermal process involving a non-isocyanate precursor of the present invention, efficiency for producing amides or polyamides can be significantly improved, and the impure side products produced from a side reaction of isocyanate can be greatly curtailed. Hence, amides or polyamides of high purity and yield can be achieved. The invention also relates to a process for preparing aromatic carbamates, the new non-isocyanate precursors for amides or polyamides.

The present invention relates to processes for producing polymeric carbodiimides by addition of cesium salts and to polymeric carbodiimides produced by this process and to the use thereof as a hydrolysis inhibitor, especially in polyurethane (PU)-based systems, preferably thermoplastic TPU, PU adhesives, PU casting resins, PU elastomers or PU foams.

The present invention relates to processes for producing polymeric carbodiimides by addition of cesium salts and to polymeric carbodiimides produced by this process and to the use thereof as a hydrolysis inhibitor, especially in polyurethane (PU)-based systems, preferably thermoplastic TPU, PU adhesives, PU casting resins, PU elastomers or PU foams.

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.

Provided is: A glove dipping composition including, at least: an elastomer that contains a (meth)acrylonitrile-derived structural unit, an unsaturated carboxylic acid-derived structural unit and a butadiene-derived structural unit in a polymer main chain; a polycarbodiimide; zinc oxide and/or an aluminum complex; water; and at least one pH modifier selected from an ammonium compound and an amine compound, in which glove dipping composition the polycarbodiimide includes at least one polycarbodiimide containing a hydrophilic segment in its molecular structure and has an average polymerization degree of 3.8 or higher and a carbodiimide equivalent of 260 to 600; the polycarbodiimide is added in an amount of 0.1 to 4.0% by weight and zinc oxide and/or the aluminum complex is/are added in an amount of 0.1 to 5.6% by weight with respect to the total solid content of the glove dipping composition; and the glove dipping composition has a pH of 9.0 to 11.5.

A method for producing a carbodiimide compound, comprising a carbodiimide production step of reacting an aliphatic tertiary isocyanate compound (A) in the presence of an organic alkali metal compound (B) having Lewis basicity.