PUR 1635 is a two-component solvent-free room temperature or heat cured polyurethane material that appears light yellow transparent after curing. It is used in two-component sealing, potting flame retardant and other fields. The raw materials are free of heavy metals, environmentally friendly, and have wide process operability. The finished product has high physical properties and good adhesion with the substrate. It can be cured at room temperature or by heating, and can be deeply cured with less heat release and low shrinkage rate during curing; After curing, it has excellent flexibility and good flame retardant effect.