Resin composition for solder resist, solder resist film, and circuit board
There are provided a resin composition for a solder resist, a solder resist film, and a circuit board that exhibit an excellent low dielectric property by a non-conventional new approach. A resin composition for a solder resist according to an embodiment of the present invention contains a thermosetting resin, an inorganic filler, and hollow resin particles, in which the hollow resin particles are contained in the resin composition for a solder resist in an amount of 1% by weight to 50% by weight.
1 . A resin composition for a solder resist comprising a thermosetting resin, an inorganic filler, and hollow resin particles,
wherein
the hollow resin particles comprise at least one selected from hollow resin particles (1) and hollow resin particles (2);
the hollow resin particles (1) comprise a shell including an aromatic polymer (P1) obtained by polymerizing a monomer composition containing an aromatic crosslinking monomer (a), an aromatic monofunctional monomer (b), and a (meth)acrylic acid ester-based monomer (c) represented by formula (1):
in which
R 1 represents H or CH 3 ,
R 2 represents H, an alkyl group or a phenyl group,
R 3 —O represents an oxyalkylene group having 2 to 18 carbon atoms, and
m is an average addition molar number of the oxyalkylene group and represents an integer of 2 to 30;
the hollow resin particles (2) comprise a polymer (P) containing a structural unit (I) derived from a vinyl-based monomer and a structural unit (II) derived from a phosphoric acid ester-based monomer; and
the hollow resin particles are contained in the resin composition for a solder resist in an amount of 1% by weight to 50% by weight with respect to the total solid content of the resin composition for a solder resist.
2 . A solder resist film formed from the resin composition for a solder resist according to claim 1 .
3 . A circuit board comprising a substrate and a conductive circuit formed on the substrate,
wherein the solder resist film according to claim 2 is formed on an outermost layer of the substrate.