| 摘要 |
PROBLEM TO BE SOLVED: To produce an expanded sheet, comprising a specific aromatic vinylic polymer, having a long product life, moldable into a molding product excellent in strength and oil resistance and useful as containers, etc., for oily foods. SOLUTION: This expanded sheet comprises (A) an ionic cross-linked aromatic vinylic polymer [e.g. the one having 150000-1000000 molecular weight (W1 ) in an undissociated state expressed in terms of the solution viscosity in dry toluene (T) and 100000-400000 molecular weight (W2 ) in a dissociated state expressed in terms of the solution viscosity in a mixed solution of T with hydrochloric acid at 1.05-5 molecular weight ratio W1 /W2 ] and is obtained by carrying out the expansion extrusion molding so as to provide 3-20 times expansion ratio and 1-5mm thickness. The component A is prepared by copolymerizing, e.g. an aromatic vinylic monomer with a metallic salt of (meth)acrylic acid such as zinc (meth)acrylate as essential components. |
