| 摘要 |
PROBLEM TO BE SOLVED: To stably prepare a foamed sheet of a styrene/(meth)acrylic acid copolymer compsn. having good surface appearance at a high discharge. SOLUTION: This process for preparing a foamed sheet comprises using a styrene/(meth)acrylic acid copolymer satisfying the following requirements: (A) the wt. average mol.wt.(Mw), in terms of polystyrene, as measured by gel permeation chromatography is in the range of 15 to 400,000, (B) the content of (meth)acrylic acid is 1 to 30wt.%, and (C) the viscosityηe defined byηe=9(n+1)<2> P0 <2> /32ηγas measured at a shear rate ofγ=9×10<2> (s<-1> ) and a temp. of 220±3 deg.C and the melt flow rate(MFR) as measured at a load of 5kg and a temp. of 200 deg.C satisfies 55,000>ηe>22,000-6,900×(MFR). |
