Patent ID: 8309681

Claim:
A method for producing a resin particle (X), comprising: treating a resin particle (B) containing a resin (A) with liquid or supercritical carbon dioxide (C), wherein the resin (A) is a block polymer of a crystalline part (a) containing, as an essential constitutional component, a lactone ring-opening polymer (p), and a noncrystalline part (b); removing (C); obtaining the resin particle (X), wherein a heat of fusion measured by differential scanning calorimetry (DSC) of the obtained (X) satisfies the following relational formula (I): 0 ≦H 2 /H 1≦0.9 (1) [wherein H1 represents a measurement value of a heat of fusion (J/g) at the time of the initial temperature elevation measured by DSC; and H2 represents a measurement value of a heat of fusion (J/g) at the time of the second temperature elevation measured by DSC] wherein the resin (A) is a resin having a melting point (m) of 40 to 110° C., a ratio (s/m) between a softening point (s) (° C.) and a melting point (m) (° C.) of 0.8 to 1.55, a melting starting temperature (x) within a temperature range of (m±20)° C., and satisfying the following requirements: G ′( m+ 20)=50 to 1×10 6 (Pa) Requirement 1 |Log G ″( x+ 20)−Log G ″( x )|>2.0 Requirement 2 wherein G′ is storage elastic modulus (Pa), and G″ is loss elastic modulus (Pa).