Epoxy resin cured products, epoxy resin compositions, prepregs, laminates and printed wiring boards

Abstract

This invention provides an epoxy resin composition that combines low dielectric properties and low melt viscosity, resulting in a cured product exhibiting excellent dielectric properties, and an epoxy resin cured product using the same. An epoxy resin cured product, used as an insulating material, wherein the components contained in the cured product are separated into three components according to the order of spin-spin relaxation time from shortest to longest: a hard component at 120°C, a medium component at 120°C, and a soft component at 120°C, based on the free induction decay curve obtained using pulsed NMR determined by solid-state echo method. Furthermore, based on the free induction decay curve obtained using pulsed NMR determined by solid-state echo method at 160°C, the components contained in the cured product are separated into three components according to the order of spin-spin relaxation time from shortest to longest: a hard component at 160°C, a medium component at 160°C, and a soft component at 160°C. When the three components are the soft component, in the total of 100% of the content of the hard component at 160°C, the content of the medium component at 160°C, and the content of the soft component at 160°C, the content of the hard component at 160°C is 10% or more and less than 60%, the ratio of the spin-spin relaxation time of the hard component at 160°C to the spin-spin relaxation time of the hard component at 120°C is 1.30 or more, the spin-spin relaxation time of the hard component at 120°C is 10.0 microseconds or more and less than 22.0 microseconds, and the spin-spin relaxation time of the hard component at 160°C is 18.0 microseconds or more and less than 30.0 microseconds.

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