Abstract: The present invention is a curable resin composition comprising a copolymer (A) represented by the following general formula (1), silica fine particles (B), a reactive monomer (C) and a polymerization initiator (D). In the general formula (1), X is an atomic group formed by removing “k” mercapto groups from a multifunctional thiol compound having at least “k” mercapto groups; Y is a monovalent organic group derived from a copolymer formed by copolymerizing unsaturated monomers; and “k” is an integer of 3 to 10. The present invention can provide a hard coat agent which has low curing shrinkage and which has both low curing shrinkage and antiblocking properties as needed; a hard coat film and a hard-coat treated plastic substrate having high pencil hardness and low curling properties, by using this hard coat agent.

Abstract: It is an object of the present invention to provide a curable composition capable of forming a heat-resistant cured film which is excellent in surface hardness, is good in flexibility and bending properties, and has strength and flexibility that are compatible with each other, and a cured product (film) of the composition. The curable composition includes a reactive (meth)acrylate polymer (A) having a monomer unit represented by the following formula (1), a polymerization initiator (B) and a reactive monomer(C): wherein R1 is a hydrogen atom, a methyl group or an ethyl group, R2 is a hydrogen atom or a methyl group, X1 is a straight-chain or branched hydrocarbon group of 2 to 6 carbon atoms or an alcohol residue of polyethylene glycol, polypropylene glycol or caprolactone-modified both-terminal diol, n is an integer of 2 to 4, and m is an integer of 1 to 5.

Abstract: It is an object of the present invention to provide a urethane compound capable of providing a cured product which is excellent in surface hardness, scratch resistance, flexibility and bending property, has reduced curling property and also has good transparency, a curable composition containing the same and a cured product thereof. The curable composition of the present invention is characterized by containing a specific urethane compound having an isocyanurate ring skeleton and a polymerization initiator.