摘要 |
The invention provides a composition and process for producing expandable beads from a compostable or biobased thermoplastic polymer. A key aspect of this invention is the ability to incorporate sufficient amounts of hydrocarbon blowing agent into the matrix of the compostable or biobased polymer. The following process may be used. First, the raw materials of compostable or biobased polymers, hydrophobic additive, and other additives are mixed by melt processing techniques, Next, a hydrocarbon blowing agent is added to the admixture, either by addition into the melt or by impregnation into the solid, to produce an expandable bead. Small, lightweight, foamed beads are produced by heating the expandable bead. Then, the expanded beads are subsequently used in conventional operations for molding into foamed articles. |