Blocking agent for an isocyanate group and isocyanate protected by said blocking agent

Abstract

One of the purposes of the present invention is to provide a blocking agent for blocking an isocyanate group to thereby prepare an isocyanate compound which has excellent water resistance and is react with another polymerizable compound to be cured at a relatively low temperature; and another purpose is to provide a blocked isocyanate having an isocyanate group blocked with the blocking agent. The present invention provides a blocking agent for blocking an isocyanate group, wherein the blocking agent is an organic silicon alcohol having an organic group bonded to a silicon atom and said organic group is capable of forming a β-silyl cation together with the silicon atom. In a preferred embodiment, the present invention provides a blocking agent which is an organic silicon alcohol represented by the general formula (1). In the formula (1), Ris an alkylene group having 3 to 5 carbon atoms and may have a substituent, provided that the number of carbon atoms of the substituent is not included in the number of the carbon atoms of the alkylene group, Ris an alkyl group having 1 to 10 carbon atoms, Z is an organic group capable of forming a β-silyl cation together with the silicon atom to which Z bonds, and n is an integer of 1 to 3. The present invention further provides a blocked isocyanate having a structure in which the isocyanate group is blocked with the aforesaid blocking agent and a thermosetting composition comprising the blocked isocyanate.