Patent ID: 8058327

Claim:
An epoxy resin composition consisting of: (a) an epoxy resin having on average more than one 1,2-epoxide groups in the molecule; (b) a hardener-accelerator system consisting of (b1) a polycarboxylic acid anhydride; and (b2) a sulfonium salt; (c) a non-alkaline, inorganic filler present as a mixture of at least two different particle sizes whereby the larger particles have a D50-value of between 11 and 25 Î¼m and the smaller particles have a D50-value of between 4 and 10 Î¼m and whereby the amount by weight of the filler having the larger particle sizes is at least twice the amount by weight of the filler having the smaller particle sizes and wherein the inorganic filler (c) is selected from quartz flour, fused quartz, wollastonite, aluminium silicate, glass powder mica and a mixture thereof; and optionally (d) a polymerization inhibitor, pigment, dye, flame retardant, antistatic, adhesion promoter, flow control agent, antioxidant or light stabilizer.