发明授权
US2995530A Polyurethane composition containing an nu, nu'-bis (hydroxy-alkyl) piperazine and preparation of same 失效
含有nu,nu'-双(羟基 - 烷基)哌嗪的聚氨酯组合物及其制备方法

Polyurethane composition containing an nu, nu'-bis (hydroxy-alkyl) piperazine and preparation of same
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