Intellectual Property Office
Non-Confidential Disclosures
“Blends of Polyurethane and Polyphosphazene for Flame-Retardant Foamed Compositions”
PSU Inv. Disc. No 96-1552
Keywords:
Polyphosphazene; polyurethane; Flame retardant
Inventors:
H.R. Allcock, M.M. Coleman, K.S. Guigley, C.S. Reed
Links:
US Patent 5,965,627
http://research.chem.psu.edu/hragroup/
Background:
Considerable interest exists in the development of flame-retardant polymers for a wide range of applications. Most conventional organic polymers have useful structural and mechanical properties, but are limited by their low thermo-oxidative stability. A typical example is found in polyurethanes. However, polyurethanes are highly combustible. Three general approaches exist to reducing the flammability of polyurethanes; (1) the addition of small molecule flame retardants; (2) modification of the polyurethane structure to influence the thermal decomposition pathways; and (3) blending with other polymer systems to enhance the thermo-oxidative stability of the resulting material. Each approach has its advantages and disadvantages. The first approach, the addition of small molecule flame retardants, is relatively easy and inexpensive but suffers from the problem of migration or leaching of the small molecules out of the system. This limits their effectiveness over long periods of time. In addition, the small molecule additives may influence the decomposition reactions in a way that increases the production of smoke and toxic vapors, thus hampering emergency countermeasures and increasing the likelihood of death by inhalation. The second approach, the modification of the polymer structure, is often higher in cost and can compromise the mechanical properties. The third approach, which involves blending of the polyurethane with other polymers, could utilize a polymer that inhibits combustion by modifying the decomposition mechanism of the polyurethane, by the release of noncombustable gases, and/or by undergoing reactions during heating to create a high char yield to quench further combustion. However, the choice of suitable polymeric flame-retardants is restricted to species that allow retention of advantageous mechanical properties of the polyurethane.
Invention description:
The invention relates to flame-retardant polymer blends of a polyurethane polymer or prepolymer and a poly(organophosphazene). Preferred poly(organophosphazenes) contain functional groups capable of reacting with isocyanate groups present during the curing of the polyurethane. The blends are preferably formulated by reacting the poly(organophosphazene) containing functional groups under conditions where some of the functional groups of the poly(organophosphazene) can react with the isocyanate groups present during the polymerization and curing of the polyurethane. These polymer blends are useful for making flame-retardant foamed articles of manufacture.
Advantages:
- Flame retardant foamed compositions
Contact:
Bradley A. Swope
Sr. Technology Licensing Officer
Intellectual Property Office
113 Technology Center
The Pennsylvania State Univ.
University Park, PA 16802-7000
Phone: (814) 8673-5387
Fax: (814) 865-3591
E-mail: bradswope@psu.edu |
