urethane (meth) acrylate monomer, process to produce urethane, monomer composition, optical material, photochromic composition, and photochromic cured product

摘要

urethane (meth) acrylate monomer, process for producing the same, monomer composition, optical material, photochromic composition, and photochromic cured product. a process for producing a urethane (meth) acrylate monomer having a low acidity index and low content of a hardly soluble high molecular weight impurity that is highly dimensionally cross-linked, comprising the steps of: (1) contacting a first solution containing a urethane (meth) acrylate monomer having an acidity index of less than 0.2 mhkoh / g and an organic solvent for a water adsorbent capable of adsorbing an acid component to obtain a second solution containing a (meth) monometer urethane acrylate having an acidity index of not more than 0.2 mgkoh / g, the organic solvent and more than 5,000 ppm (mass) of water based on urethane (meth) acrylate monomer; (2) contacting the second solution with a dehydrating agent to obtain a third solution containing no more than 5,000 ppm (mass) of water based on urethane (meth) acrylate monomer; and (3) removing the organic solvent from the third solution.