PRESSURE-RESPONSIVE PARTICLES

Pressure-responsive particles include pressure-responsive base particles and silica particles, in which the pressure-responsive base particles contain a styrene-based resin that contains styrene and other vinyl monomers as polymerization components and a (meth)acrylic acid ester-based resin that contains at least two kinds of (meth)acrylic acid esters as polymerization components and in which a ratio of a mass of the (meth)acrylic acid esters to a total mass of polymerization components is 90% by mass or more, the pressure-responsive particles have at least two glass transition temperatures, a difference between a lowest glass transition temperature and a highest glass transition temperature is 30°C or higher, and a ratio of a surface coating rate Cs2 by the silica particles after application of the following first stress to a surface coating rate Cs1 by the silica particles before application of stress satisfies a relationship of 0.4 ≤ Cs2/Cs1 ≤ 0.8, first stress: 10 g of the pressure-responsive particles and 90 g of resin-coated ferrite particles are put in a V-shaped mixer with a rotary container having a volume of 0.5 L and rotated at a rotation speed of 40 rpm for 20 minutes at a temperature of 20°C and a relative humidity of 50%.