Resin composition, prepreg, metal foil with resin, laminate, printed wiring board, and method for producing resin composition

A prepreg, which is prepared by impregnating a base material with a resin composition comprising an acrylic polymer (A) and a thermosetting resin (B), wherein a phase separation structure of a first phase containing the acrylic polymer (A) and a second phase containing the thermosetting resin (B) is formed, and an average domain size of the second phase is 20 μm or less,

• wherein in case that ten sheets of the prepreg which were processed into a size of 250 mm×250 mm are superimposed and put into a hermetically sealable bag, which is then charged in a constant-temperature and constant-humidity environment at a temperature of 25° C. and a humidity of 70% for 48 hours, the prepreg arranged in the bottom and the prepreg adjacent thereto are separated from each other,
• wherein a solubility parameter (SP value) of the acrylic polymer (A) is from 9.0 to 12.0, and
• wherein an absolute value of a difference between the solubility parameter (SP value) of the acrylic polymer (A) and a solubility parameter (SP value) of the thermosetting resin (B) is from 0.1 to 5.0.