Establishment of recovery method of available substances from polyurethane by chemical decomposition

本研究的目的是建立化学分解法回收聚氨酯泡沫中多元醇的方法。采用单乙醇胺（MEA）或异丙醇胺（IPA）在170℃的温度下对甲基二苯基异氰酸酯（MDI）基聚氨酯泡沫进行分解。无论采用何种分解剂，分解液均分为两层。由于多元醇在MEA分解时只存在于上层，而在IPA分解时分布于两层，因此MEA优于IPA。经MEA分解得到的上层用己烷萃取，提高多元醇的纯度。提取液被分成三层。中间层存在大量的多元醇，其中多元醇占重量的72%，己烷占20%，副产物占8%。通过GPC、HPLC和NMR分析，发现MDI和聚合物MDI的产物分别为二苯基甲二胺（DAM）和聚合物DAM。回收的多元醇含己烷及其副产品，与原始多元醇按不同比例混合，用于再生聚氨酯泡沫。当多元醇含量达到30%时，得到了结构良好的泡沫。

The purpose of this study is to establish the recovery method of polyol from polyurethane foam by chemical decomposition. Methylendiphenylisocyanate (MDI) -based polyurethane foam was decomposed by monoethanolamine (MEA) or isopropanolamine (IPA) at 170ﾟC.The decomposing liquid was separated into two layrs regardless of decomposing agent. MEA was superior to IPA because polyol was contained only in the upper layr in the case of MEA decomposition, and was distributed in the both layrs for IPA decomposition.The upper layr obtained by MEA decomposition was extracted by hexane to raise the purity of polyol. The extracted liquid was separated into three layrs. A large amount of polyol existed in the middle layr, in which polyol was contained 72% by weight, hexane 20%, and by-products 8%. The by-products were found to be diphenylmethanediamine (DAM) or polymeric DAM, which were derived from MDI or polymeric MDI, by GPC, HPLC, and NMR analyzes.The recovered polyol containing hexane and by-products, was used for re-producing polyurethane foam by mixing in various ratios with virgin polyol. A good cellular structure foam was obtained with recovered polyol weight up to 30%.