An N-hydroxycarbamate compound of the formula ROCONHOH in which R is C.sub.1-8 alkyl, C.sub.3-12 cycloalkyl, aryl or aralkyl group, is produced by reacting a carbonic acid diester of the formula ROCOOR in which R is as defined above, with hydroxylamine in the presence of a basic substance, for example, an alkali metal hydroxide or alkoxide.

A polycarbamic acid ester-type curing agent for thermosetting resin paints, said curing agent containing per molecule at least two groups represented by the following formula ##STR1## wherein Y represents ##STR2## --O--, or --S--; R.sub.1 represents a direct bond, or a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a hydroxyl group or an alkoxy group, provided that when Y is ##STR3## R.sub.1 represents a direct bond; R.sub.2 and R.sub.4, independently from each other, represent a hydrogen atom, or an aliphatic hydrocarbon group having 1 to 6 carbon atoms which may be substituted by an amino group, a hydroxyl group or an alkoxy group, or a group of the formula ##STR4## and R.sub.3 represents a hydrogen atom or a monovalent aliphatic hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a hydroxyl group or an alkoxy group.

Process for the preparation of acylurethanes by reacting a urethane with compounds containing hydroxyl groups, which comprises reacting a hydroxy compound (A) with a urethane (B) in the form of an imide of the formula ##STR1## to give an acylurethane containing at least one grouping of the formula --CO--R--CO--NH--COOR.sup.1 (II). In these formulae, R denotes the hydrocarbon radical of an optionally .alpha.,.beta.-ethylenically unsaturated, aliphatic, cycloaliphatic or aromatic dicarboxylic acid or endomethylene derivatives thereof, and R.sup.1 denotes alkyl, alkoxy, alkoxyalkyl, cycloalkyl or benzyl. These acylurethanes are suitable for use as self-crosslinking curing agents or as curing agents for polyhydroxy compounds for the production of shaped articles and/or coatings.

There is disclosed an improved process for cross-linking polymers by contacting said polymers with a cross-linking agent at an elevated temperature. The improvement comprises using as the cross-linking agent a compound of the formula ##STR1## wherein R.sub.1 and R.sub.2 are independently selected from the group consisting of alkyl groups having 1-22 carbon atoms, alkenyl groups having 2-22 carbon atoms, cyclohexyl groups having 6-20 carbon atoms, phenyl groups having 6-20 carbon atoms, aralkyl groups having 7-20 carbon atoms, alkyloxy groups having 1-22 carbon atoms, alkenyloxy groups having 2-22 carbon atoms, and cyclohexyloxy groups having 6-20 carbon atoms, all of which groups may be substituted or unsubstituted; R.sub.3 is selected from the group consisting of hydrogen, alkyl groups having 1-22 carbon atoms, alkenyl groups having 2-22 carbon atoms, cyclohexyl groups having 6-20 carbon atoms, phenyl groups having 6-20 carbon atoms, aralkyl groups having 7-20 carbon atoms, and ##STR2## wherein R.sub.4 is independently selected from the same group as R.sub.1 and R.sub.2 as defined above, all of which groups may be substituted or unsubstituted; provided that when R.sub.3 is hydrogen, R.sub.1 represents an alkyloxy, alkenyloxy or cyclohexyloxy group as defined above.

Hydrocarbyl esters of N-cyclopropyl-N-hydrocarbylcarbamic acids, such as ethyl N-benzyl-N-cyclopropylcarbamate, are effective coupling agents for conjugated diene polymerization systems employing an alkali metal-based initiator.