PRODUCTION OF PREPREG

摘要

PROBLEM TO BE SOLVED: To obtain a prepreg comprising a glass substrate uniformly coated and impregnated with a constant amount of a solvent-free epoxy resin composition and not having a difference between the appearances of the front and back surfaces by coating one surface of the substrate with the solvent-free epoxy resin composition comprising a specific composition by the use of a die coater and subsequently heating the coated epoxy resin composition. SOLUTION: This method for producing the prepreg comprises coating one surface of a glass substrate with a solvent-free epoxy resin composition by the use of a die coater and subsequently heating the coated epoxy resin composition. The resin composition is obtained by heating (A) an epoxy resin containing a liquid epoxy resin having two or more epoxy groups per molecule and having a viscosity of 1000-30000cps at 25 deg.C in an amount of >=50wt.% and (B) a phenolic compound having two or more phenolic hydroxyl groups per molecule at 100-180 deg.C, and subsequently mixing the obtained primary mixture with a curing accelerator containing (C) dicyandiamide and (D) a compound of the formula [(n) is an integer of 1-4; (m) is 1, 2; R is an m-valent organic group] as essential components at a temperature of <=90 deg.C within 4hr before coated on the glass substrate.