The spray-wound prefabricated direct-buried insulation pipe has the following advantages compared wi

1. The requirements for the tensile yield strength and elongation at the break of the polyethylene outer protective pipe are improved.

2. Reduce the ratio of recycled materials for the polyethylene outer protective pipe.

3. Reduce the wall thickness of the polyethylene outer protective pipe. 4. Improve the water absorption requirements of the rigid polyurethane foam insulation layer.

5. The requirement for the closed cell ratio of the rigid polyurethane foam insulation layer is improved.

s6. The requirements for the compressive strength of the rigid polyurethane foam insulation layer are improved.