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| 配方类型： |
RUBBER, PLASTICS, WAXES |
| 配方说明： |
Rigid Foamed Urethane |
| 配制方法： |
Rigid fluorocarbon-blown or water-blown urethane foams based on PAPI (polymethylene polyphenylisocyanate) are fundamentally less combustible than diisocyanate-based foams of like density. This is due to the property possessed by "PAPI" rigid foams of charring without melting at flame temperature. The char that forms excludes air and protects the remainder of the sample from burning. Additives that help to exclude air from foams when they are exposed to flame are effective in lower concentration with "PAPI" foam formulations than with diisocyanate-based foams.
There are many additives that aid in excluding air from otherwise combustible materials. In the technology of rigid urethane foam those that can be covalently reacted into the molecule of the organic polymer have shown durable flameretardant properties. The polyhalogenated resins or the phosphorus-containing resins appear to be outstanding and they can be used either singly or in mixtures to give the foam maker considerable choice of formulations. B |
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