Heat-curable maleimide resin composition for RTM, fiber-reinforced composite material and radome

A heat-curable maleimide resin composition for RTM, comprising:

• (A-1) a maleimide compound having at least one dimer acid skeleton-derived hydrocarbon group per one molecule, and having a viscosity of not higher than 3 Pa·s;
• (A-2) a maleimide compound having at least one dimer acid skeleton-derived hydrocarbon group per one molecule, having a viscosity of greater than 20 Pa·s, and exhibiting a fluidity at 25° C.;
• (B) a radical polymerization initiator;
• and
• (C) a polymerization inhibitor,
• wherein the viscosities of the components (A-1) and (A-2) are measured in accordance with a method described in JIS Z8803:2011, at a measurement temperature of 25° C., and using a Brookfield-type rotary viscometer with a rotation rate of a spindle being set to 5 rpm,
• wherein the component (A-1) is a maleimide compound represented by the following formula (1):
• wherein A represents a dimer acid skeleton-derived hydrocarbon group,
• wherein the component (A-2) is a maleimide compound represented by the following formula (2):
• wherein B independently represents a cyclic structure-containing tetravalent organic group, X independently represents a divalent hydrocarbon group having 6 to 200 carbon atoms, at least one X is a dimer acid skeleton-derived hydrocarbon group, and n is 1 to 100, and wherein B in the formula (2) is any one of the tetravalent organic groups represented by the following structural formulae:
• wherein bonds in these structural formulae that are yet unbonded to substituent groups are to be bonded to carbonyl carbons forming cyclic imide structures in the formula (2),
• wherein a ratio between (A-1) and (A-2) on a mass basis is (A-1):(A-2)=95:5 to 40:60.