| abstract |
It is an object of the present invention to provide a method for suppressing a decrease in thermal fusion between expanded particles, thereby suppressing a decrease in mechanical strength of an in-mold foam molded product. SOLUTION: In-mold foam molding having a foaming ratio of 5 to 60 times, a porosity of 10 to 30%, a sound absorption rate of 0.3 or more, a bending break point displacement of 10 mm or more, and a dimensional change rate of 1.5% or less. A method for producing pre-foamed particles used in the production of a body, comprising a foaming agent and having a mass ratio of 20/80 to 50/50 and derived from composite resin particles of polypropylene resin and polystyrene resin The above-mentioned problems are solved by a method for producing pre-expanded particles, characterized in that the pre-expanded particles are obtained by pre-expanding the particles and then preparing the residual foaming agent amount to be reduced to 0 to 3% by mass. [Selection figure] None |