Low dk/df solder resistant composition use for printed circuit board

A low Dielectric constant (Dk)/Dielectric dissipation factor (Df) solder resistant composition comprising following components:

• A. a photopolymerizable prepolymer (represented by formula 1) the total amount of resin is 50 to 70 weight % (total amount of resin is defined as the sum of component (A) to component (D)), and prepared by reacting (a1) dicyclo pentadiene-phenol novolac multifunctional epoxy, or (a2) polyphenyl ether modified multifunctional epoxy resin or any combination of two (a1), (a2) with (b) mono carboxlic acid containing a vinyl group, then reacting with (c) a saturated or unsaturated poly anhydride acid;
• B. a photopolymerizable vinyl monomer the total amount of resin is 5 to 20 weight % as thinner;
• C. an epoxy compound the total amount of resin is 10 to 30 weight % comprising (C1) dicyclo pentadiene-phenol novolac multifunctional epoxy resin or polyphenyl ether modified epoxy resin or any combination of the forgoing two kinds of resins;
• (C2) tetra methyl biphenol epoxy resin;
• D. a photopolymerization initiator the total amount of resin is 5 to 20 weight %;
• E. an inorganic filler 10˜30 weight %;
• F. a catalyst 0˜2.0 weight %;
• G. an organic solvent 10˜30 weight %;