Polyurethane systems with chemical blowing for integrated pipe insulation within polyethylene casings

The study considers the possibility of applying chemically foamed polyurethane systems as an alternative to polyurethane foams produced with acyclic and cyclic hydrocarbon blowing agents (pentane, cyclopentane) in the manufacture of pre-insulated pipes of the steel-polyurethane-polyethylene type. The basis for analysis and investigation was industrial systems in which foaming occurs due to the reaction of isocyanate with water, generating carbon dioxide without the use of external blowing agents. A comparison of the properties of the resulting foam with the requirements of current international standards confirmed full compliance of density, strength, and thermal conductivity indicators with normative limits. Certification tests of finished pipes and fittings, carried out in accredited laboratories, demonstrated the stability of the insulation structure and the level of adhesive interaction in steel-polyurethane-polyethylene systems. Chemical foaming makes it possible to eliminate explosive agents, reduce environmental impact, and simplify production without loss of thermal insulation efficiency. The obtained results confirm the feasibility of using chemically foamed systems as a baseline solution for modern heat-insulated pipelines.