The invention belongs to the technical field of
polyurethane, and particularly relates to combined polyether for
continuous production of PIR block foam, as well as a preparation method and application of the combined polyether. The combined polyether consists of a component A and a component B, wherein the component A consists of
polyester polyol, polyether glycol, a foam stabilizing agent, a chemical
foaming agent, a catalyst, a
fire retardant and a physical
foaming agent, and the component B is polymethylene polyphenyl polyisocyanate. While in use, materials in the component A and materials in the component B are mixed through a high-pressure foaming
machine, so that PIR high-
flame-resistant block foam can be in
continuous production. According to the combined polyether disclosed by the invention, the production process of the materials in the component A is simple, and the
discharge of three wastes is not generated; the production of a PIR type heat insulation material through the materials in the component A and the materials in the component B is simple in operation technology and easy to operate, the volatilization of gas destroying an
atmospheric layer is not generated, the product quality is stable, the production cost is low, and when the
environmental protection purpose is achieved, products are good in low-temperature size stability, good in
flame resistance, uniform in
density distribution, low in
thermal conductivity, high in
compressive strength and low in water absorption.