Resin composition, prepreg, resin-equipped film, resin- equipped metal foil, metal-clad laminate, and wiring board

A resin composition comprising:

• a preliminary reaction product (A) obtained by previously reacting a polyphenylene ether compound (a1) having a hydroxyl group in a molecule and an acid anhydride (a2) having an acid anhydride group in a molecule;
• and
• a curable resin (B) containing a reactive compound having an unsaturated double bond in a molecule,
• wherein
• the curable resin (B) contains a maleimide compound (B1) and a reactive compound (B2) other than the maleimide compound (B1),
• the reactive compound (B2) includes at least one selected from the group consisting of an unsaturated double bond-modified polyphenylene ether compound having a terminal modified with a substituent having an unsaturated double bond, an allyl compound, an acrylate compound, a methacrylate compound, a polybutadiene compound, and a styrene compound,
• the number of carbon atoms in the acid anhydride (a2) is 6 or more and 25 or less,
• an equivalent ratio of the acid anhydride group in the acid anhydride (a2) to the hydroxyl group in the polyphenylene ether compound (a1) is 1.5 or less, and
• a content of the curable resin (B) is 20 to 85 parts by mass with respect to 100 parts by mass of a sum of the preliminary reaction product (A) and the curable resin (B).