Curable resin composition

A curable resin composition comprising a polyphenylene ether, wherein:

• the average number of phenolic hydroxyl groups per molecule of said polyphenylene ether is 0.3 or more,
• the resin flow rate of said curable resin composition at curing as measured under the following conditions is from 0.3 to 15%,
• a sample for dielectric loss tangent measurement produced from said curable resin composition under the following conditions has a dielectric loss tangent at 1 GHz of 0.005 or less,
• a sample for glass transition temperature measurement produced from said curable resin composition under the following conditions has a glass transition temperature of 170° C. or more,
• assuming that two 150 mm-square prepreg sheets obtained by impregnating a glass cloth specified by IPC Style 2116 with said curable resin composition to have a resin content of 60±2 mass % are stacked to obtain a laminate sheet precursor and a laminate sheet is produced by molding said laminate sheet precursor under the following condition (a) and removing the resin part flowed out, said resin flow rate at curing is a value calculated from the mass (g) of said laminate sheet and the mass (g) of said laminate sheet precursor according to the following formula:
• Resin flow rate (%) at curing=(mass (g) of laminate sheet precursor−mass (g) of laminate sheet)/mass (g) of laminate sheet precursor×100,
• said sample for dielectric loss tangent measurement is molded under the following condition (a) after stacking 16 prepreg sheets obtained by impregnating a glass cloth specified by IPC Style 2116 with the curable resin composition to have a resin content of 60±2 mass %, and
• said sample for glass transition temperature measurement is molded under the following condition (a) after stacking 2 prepreg sheets obtained by impregnating a glass cloth specified by IPC Style 2116 with the curable resin composition to have a resin content of 60±2 mass %,
• Condition (a):
• vacuum pressing is performed under the condition of a pressure of 5 kg/cm2 while heating at a temperature rise rate of 3° C./min from room temperature;
• when reached 130° C., vacuum pressing is performed under the condition of a pressure of 30 kg/cm2 while heating at a temperature rise rate of 3° C./min;
• and when reached 200° C., vacuum pressing is performed under the conditions of a pressure of 30 kg/cm2 and a time for 60 minutes while maintaining the temperature at 200° C.