Abstract: Provided is a resin composition for encapsulating which is used for forming an encapsulating resin of an on-vehicle electronic control unit including a wiring substrate, a plurality of electronic components mounted on the wiring substrate, and the encapsulating resin encapsulating the electronic component, the resin composition including: a thermosetting resin; and one or more imidazole compounds, in which when a torque value is measured over time under conditions of the number of rotations of 30 rpm and a measurement temperature of 175° C. by using Labo Plastomill, a time T1 at which the torque value is less than or equal to 2 times a minimum torque value is longer than or equal to 15 seconds and shorter than or equal to 100 seconds, and the minimum torque value is greater than or equal to 0.5 N·m and less than or equal to 2.5 N·m.

Abstract: Provided is a resin composition for encapsulating which is used for forming an encapsulating resin of an on-vehicle electronic control unit including a wiring substrate, a plurality of electronic components mounted on the wiring substrate, and the encapsulating resin encapsulating the electronic component, the resin composition including: a thermosetting resin; and imidazoles, in which when a torque value is measured over time under conditions of the number of rotations of 30 rpm and a measurement temperature of 175° C. by using Labo Plastomill, a time T1 at which the torque value is less than or equal to 2 times a minimum torque value is longer than or equal to 15 seconds and shorter than or equal to 100 seconds, and the minimum torque value is greater than or equal to 0.5 N·m and less than or equal to 2.5 N·m.

Abstract: An epoxy resin composition which comprises an epoxy resin (A), a curing agent (B), a curing accelerator (C) and a component retarding curing of the epoxy resin (D) which is at least one component selected from components (a), (b) and (c) represented by general formulae [1], [2] and [3], respectively, a semiconductor device having a semiconductor element encapsulated by using the composition, and a process for providing latency to an epoxy resin composition. The epoxy resin exhibits excellent storage stability, excellent fluidity and curing property during encapsulating by molding and excellent resistance to soldering without forming cleavages or cracks by the soldering treatment at high temperatures in accordance with the lead-free soldering. An epoxy resin composition can be provided with latency by adjusting the amounts of the curing accelerator and the component for retarding curing.

Abstract: An epoxy resin composition which comprises an epoxy resin (A), a curing agent (B), a curing accelerator (C) and a component retarding curing of the epoxy resin (D) which is at least one component selected from components (a), (b) and (c) represented by general formulae [1], [2] and [3], respectively, a semiconductor device having a semiconductor element sealed by using the composition, and a process for providing latency to an epoxy resin composition. The epoxy resin exhibits excellent storage stability, excellent fluidity and curing property during sealing by molding and excellent resistance to soldering without forming cleavages or cracks by the soldering treatment at high temperatures in accordance with the lead-free soldering. An epoxy resin composition can be provided with latency by adjusting the amounts of the curing accelerator and the component for retarding curing.