Rigid polyurethane foams used in artificial wood roofing materials

摘要

The market for using polyurethane materials as replacements for wood construction materials continues to grow and expand into new application areas. PU systems as artificial wood construction materials offer a number of benefits over traditional wood products: improved rot resistance, minimal insect damage, high impact damage tolerance, strong fire resistance, and overall less maintenance and upkeep. One particularly demanding application is the use of rigid PU foam as a high performance roofing material. Recent advances in PU formulation and accelerated testing methods have helped to improve the dimensional stability of a polyurethane-based roofing material. There are a number of international, US governmental, and state building codes and ASTM methods that have been designed to assess the suitability of plastic and polyurethane systems as construction materials/Often encompassing various fire, mechanical performance, and simulated exposure experiments, these tests are designed to ensure an adequate performance over the expected lifetime of the product. This paper highlights the development of PU rigid foam that meets the demanding requirements of a PU roofing material and the creation of a new cyclic thermal exposure test that demonstrated the PU's performance. The key formulation variables, theoretical modeling of the anticipated improvements, and the test development and validation are discussed.