Composition for ultrasonic probe, and silicone resin for ultrasonic probe

A composition for an ultrasonic probe which contains a polyorganosiloxane mixture including at least three different polyorganosiloxanes,

• wherein the polyorganosiloxane mixture includes (A) a polyorganosiloxane having a vinyl group, (B) a polyorganosiloxane having two or more Si—H groups in a molecular chain, and (C) a branched polyorganosiloxane represented by the following General Formula (C), and
• the content of the polyorganosiloxanes (A), (B), and (C) is respectively 10 to 99.4 parts by mass, 0.5 to 90 parts by mass, and 0.1 to 40 parts by mass, with respect to 100 parts by mass of the total mass of the polyorganosiloxanes (A), (B), and (C),
• in General Formula (C),
• R1 to R4 each independently represent an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group,
• m represents an integer of 1 or more and n represents 0 or an integer of 1 to 5,
• a plurality of R1's, a plurality of R2's, a plurality of R3's, a plurality of R4's, and a plurality of m's may be the same as or different from each other, each group of R1 to R4 may be further substituted with a substituent, and
• at least two of the plurality of R4's are alkenyl groups.