| 摘要 |
<p>Improved preexpanded polyolefin resin particles are made of a base resin comprising 0.1 to 10 (preferred 0.3 - 5) parts by weight of a polymer (1), which has carboxyl groups and 100 parts by weight of a polyolefin resin. The polymer (1) is incorporated in the polyolefin resin. The resin particles have a cell diameter of 200 to 500 microns. The polyolefin resin is specified to be a propylene resin or an ethylene-propylene random co-polymer. The polymer (1) is specified to be an ethylene-acrylic acid-maleinic acid anhydride terpolymer or an ionomer in which ethylene-methacrylic acid copolymer molecules are bridged with a metallic ion. The preexpanded polyolefin resin particles are produced as follows, i) thermoelastic resin particles contg. a volatile foaming agent are dispersed in water with stirring in a pressurisable vessel, ii) the dispersion is pressurised and heated and iii) the resulting water-dispersed compounds are discharged into a low pressure atmosphere and allowed to expand and foam. In this process the thermoelastic resin is specified to be a polyolefin resin.</p> |
