| abstract |
The invention discloses a kind of preparation methods of Modified by Expandable Graphite high flame-retardant polyurethane hard bubble, this method prepares white material first: polyester polyol, polyether polyol, flame retardand polyether polyol, foam stabilizer, liquid combustion inhibitor, starting catalyst, gel-type catalyst, catalyst for trimerization and water are uniformly mixed, graphite is added, foaming agent is added after mixing and forms white material；Obtained white material will be prepared to mix with black material according to mass ratio 1:1.5~1.8, curing of foaming in constant temperature mold is injected after stirring, obtains hard polyurethane foam；Wherein, the black material is polyisocyanates.The present invention improves the oxygen index (OI) of hard polyurethane foam, and combustibility can reach non-ignitable grade, mechanical strength and good stability of the dimension, and thermal coefficient is low；There is very big price advantage compared with similar product in the market, and easily processed into type；The fire retardant of addition is non-volatile, is not easy to be precipitated, and toxicity is low, and flame retardant effect is lasting. |