| 摘要 |
PROBLEM TO BE SOLVED: To obtain an expanded resin bead composed of expanded core layer and nonxpanded coating layer cosisting respectively of each specific component, and capable of giving a molded form having physical properties comparable to those of molded form using high-melting thermoplastic resin expanded beads and also high in heat resistance temperature even by the use of a versatile molding machine. SOLUTION: This expanded resin bead is composed of (A) expanded core layer consisting of a crystalline thermoplastic resin and (B) nonexpanded coating layer consisting of an ethylene-based polymer either lower in melting point than the component A or presenting no melting point. The component A is pref. a propylene homopolymer or a copolymer of propylene and anotherα-olefin; while the component B is pref. a straight-chain low-density polyethylene or straight-chain ultra-low-density polyethylene each prepared by polymerzation using a metallocene catalyst. Use of an ethylene-based polymer composition, as the coating layer, prepared by blending 100 pts.wt. of the component B with 1-100 pts.wt. of the crystalline thermoplastic resin identical with that in the component A, affords improvement of the adhesiveness between the core layer and coating layer, therefore being favorable. The melting point of the component B is pref. 100-125 deg.C. |
