Synthesis and properties of novel phosphorus-containing hardener for epoxy resins

✍ Scribed by Jeng-Yueh Shieh; Chun-Shan Wang

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 180 KB
• Volume: 78
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/1097-4628(20001128)78:9<1636::aid-app90>3.0.co;2-g

✦ Synopsis

A novel phosphorus-containing curing agent, 2-(6-oxid-6H-dibenz͗c,e͗͘1,2͘oxaphosphorin-6-yl) phenol formaldehyde novolac [OD-PN], was prepared from phenol formaldehyde novolac resin (PN) and a reactive 2-(6-oxid-6H-dibenz͗c,e͗͘1,2͘oxa-phosphorin-6-yl)chloride (ODC) while ODC was synthesized through reaction between ophenylphenol and phosphoryl trichloride. The compound (OD-PN) was used as a reactive flame-retardant in o-cresol formaldehyde novolac epoxy resin (CNE) for electronic application. Owing to the rigid structure of ODC and pendant P group, the resulted phosphorus containing epoxy resin exhibited better flame retardancy, higher glass transition temperature, and thermal stability than the noncyclic P-containing curing agent or the bromine containing flame-retardant epoxy resin. UL 94-VO rating could be achieved with a phosphorus content of as low as 1.21% (comparable to bromine content of 6%) in the cured resin, and no fumes and toxic gas emission were observed. The relationship between the structure and flammability for both phosphorus containing curing agents OD-PN and TP-PN (triphenyl phosphate-phenol formaldehyde novolac reaction product ) are also examined.