超低密度聚乙烯    ultra low density polyethylene, ULDPE

超高分子量聚乙烯    ultrahigh molecular weight polyethylene, UHMWPE

不饱和聚酯    unsaturated polyester

不饱和橡胶    unsaturated rubber

尿素树脂    urea resin

脲醛树脂    urea-formaldehyde resin