RESIN COMPOSITION, PREPREG, METAL FOIL WITH RESIN, LAMINATE, PRINTED WIRING BOARD, AND METHOD FOR PRODUCING RESIN COMPOSITION

1 . 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.

2 . The resin composition according to claim 1 , wherein the acrylic polymer (A) is an acrylic polymer containing a (meth)acrylic acid ester-derived structural unit represented by the following general formula (A1):

wherein R 2 represents an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aryl group, or an aralkyl group; and R 1 represents a hydrogen atom or a methyl group.

3 . The resin composition according to claim 1 , wherein a solubility parameter (SP value) of the acrylic polymer (A) is from 9.0 to 12.0.

4 . The resin composition according to claim 1 , wherein a weight average molecular weight of the acrylic polymer (A) is from 100,000 to 1,500,000.

5 . The resin composition according to claim 1 , wherein the content of the acrylic polymer (A) is from 10 to 50 parts by mass based on 100 parts by mass of the total solid content of the resin composition.

6 . The resin composition according to claim 1 , wherein the thermosetting resin (B) is at least one selected from the group consisting of an epoxy resin, a cyanate resin, a bismaleimide, an addition polymer of a bismaleimide and a diamine, a phenol resin, a resole resin, an isocyanate resin, triallyl isocyanurate, triallyl cyanurate, and a vinyl group-containing polyolefin compound.

7 . The resin composition according to claim 1 , wherein the phase separation structure is a sea-island structure, a sea phase is constituted of the first phase, and an island phase is constituted of the second phase.

8 . The resin composition according to claim 1 , wherein a solubility parameter (SP value) of the thermosetting resin (B) is from 9.0 to 15.0.

9 . The resin composition according to claim 1 , wherein an absolute value of a difference between the solubility parameter (SP value) of the acrylic polymer (A) and the solubility parameter (SP value) of the thermosetting resin (B) is from 0.1 to 5.0.

10 . A prepreg, which is prepared by impregnating a base material with the resin composition according to claim 1 and then drying.

11 . A resin coated metal foil, which is prepared by laminating the resin composition according to claim 1 and a metal foil.

12 . A laminate plate, which is prepared by laminating the prepreg according to claim 10 , and then heating and pressurizing.

13 . A printed wiring board, which is prepared by subjecting the laminate plate according to claim 12 to circuit processing.

14 . A method for producing a resin composition including an acrylic polymer (A) and a thermosetting resin (B), the method comprising the following Steps 1 to 4:

Step 1: a step of determining a storage elastic modulus of a cured material of a desired resin composition;

Step 2: a step of specifying an absolute value X of a difference between a solubility parameter (SP value) of the acrylic polymer (A) and a solubility parameter (SP value) of the thermosetting resin (B) on a basis of a correlation between the absolute value X and the storage elastic modulus of the cured material;

Step 3: a step of selecting the acrylic polymer (A) and the thermosetting resin (B) so as to take the absolute value X as specified in the Step 2; and

Step 4: a step of mixing the acrylic polymer (A) and the thermosetting resin (B) as selected in the Step 3.

15 . A method for producing a resin composition including an acrylic polymer (A) and a thermosetting resin (B), the method comprising the following Steps 1 to 4:

Step 1: a step of determining heat resistance of a cured material of a desired resin composition;

Step 2: a step of specifying an absolute value X of a difference between a solubility parameter (SP value) of the acrylic polymer (A) and a solubility parameter (SP value) of the thermosetting resin (B) on a basis of a correlation between the absolute value X and the heat resistance of the cured material;

Step 3: a step of selecting the acrylic polymer (A) and the thermosetting resin (B) so as to take the absolute value X specified in the Step 2; and

Step 4: a step of mixing the acrylic polymer (A) and the thermosetting resin (B) as selected in the Step 3.

16 . A laminate plate, which is prepared by laminating the resin coated metal foil according to claim 11 , and then heating and pressurizing.