Modification of resins with isocyanatosiloxanes

A method for modifying a resin having a group reactive with an isocyanate group in a molecule which comprises reacting the resin with a polyfunctional isocyanatosiloxane which isocyanatosiloxane is obtained by effecting addition reaction between a hydrogenosiloxane having at least two SiH groups in a molecule of the following formula (V):

• ##STR39## wherein R.sup.31 to R.sup.37 are independently selected from halogen-substituted or unsubstituted monovalent hydrocarbon groups having 1 to 12 carbon atoms, X is independently a hydrogen atom or a halogen-substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, and the sum of a+b is an integer inclusive of 0, with the proviso that X at both ends are hydrogen atoms when b is equal to 0, and an isocyanate group-containing organic silicon compound having one isocyanate group and one aliphatic unsaturated hydrocarbon group in a molecule of the following formula (VI):
• ##STR40## wherein R.sup.38 to R.sup.42 are independently selected from a halogen-substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms and a group represented by ##STR41## wherein R.sup.44 to R.sup.46 are independently selected from a halogen-substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms or R.sup.38 to R.sup.42, taken together, may form a cyclic structure, with the proviso that only one of R.sup.38 to R.sup.42 is an aliphatic unsaturated hydrocarbon group, R.sup.43 is a divalent hydrocarbon group having 1 to 12 carbon atoms optionally substituted by halogen atoms, and letter m is an integer inclusive of 0.