초록 ▼

A substantially water-impermeable polyolefin foam made of expandable polyolefin beads. The polyolefin foam is prepared by a particular process in which after heating expandable polyolefin beads and before cooling the heated beads in a mold, the heated beads were allowed to stand in the state that th

A substantially water-impermeable polyolefin foam made of expandable polyolefin beads. The polyolefin foam is prepared by a particular process in which after heating expandable polyolefin beads and before cooling the heated beads in a mold, the heated beads were allowed to stand in the state that the polyolefin resin maintains the flowability.

대표청구항 ▼

A substantially water-impermeable polyolefin molded foam of expanded polyolefin beads, said molded foam being prepared by the steps of filling a mold with expandable beads, heating the expandable beads to melt-adhere the surface of the beads to each other and to expand the beads, allowing the result

A substantially water-impermeable polyolefin molded foam of expanded polyolefin beads, said molded foam being prepared by the steps of filling a mold with expandable beads, heating the expandable beads to melt-adhere the surface of the beads to each other and to expand the beads, allowing the resultant heated beads to stand in the state that the polyolefin resin maintains its flowability whereby voids between the beads are decreased so that the resultant molded foam will have a water-impermeability measured by the volume of leakage of pressurized air of 0.020 kg/cm2 through the thickness of the foam of not more than 10 ml/100 cm2min, cooling the heated beads and removing the resultant molded foam from the mold.