Synthesis of high purity o-cresol formaldehyde novolac epoxy resins
The content of total chlorine in o-cresol formaldehyde novolac epoxy resin (CNE), the main resin component for encapsulation formulation, affects the reliability of semi-conductor device greatly and it is one of the major criteria used by the electronic industry in measuring the quality of resins. A new process which synthesizes a high purity CNE with less than 300 ppm total chlorine content has been developed. This high purity resin has provided an extended device life under the accelerated stress test condition.
- [Show abstract] [Hide abstract] ABSTRACT: A reactive phosphorus-containing diol compound, bis(3-hydroxyphenyl) phenyl phosphate (BHPP), was synthesized. The compound (BHPP) was used as a reactive flame-retardant for diglycidyl ether of bisphenol-A (DGEBA). Thermal stability and the weight loss behavior of the cured polymers were studied by thermogravimetric analysis. The phosphorous-containing epoxy resin showed lower weight loss temperature and higher char yield than that of DGEBA. The high char yields and limiting oxygen index values as well as excellent UL-94 vertical burn test results of BHPP/DGEBA indicated the flame retardancy of the phosphorous-containing epoxy resins. The resulting phosphorous-containing epoxy resin exhibited better flame retardancy and higher thermal stability than the regular bromine containing flame retardant epoxy resin in encapsulation application. UL 94-VO rating could be achieved with a phosphorus content of as low as 1.5% (comparable to bromine content of 10%) in the cured resin, and no fume and toxic gas emission were observed.0Comments 61Citations
- [Show abstract] [Hide abstract] ABSTRACT: A novel phosphorus-containing curing agent, 2-(6-oxid-6H-dibenz〈c,e〉〈1,2〉oxa-phosphorin-6-yl) phenol formaldehyde novolac [OD-PN], was prepared from phenol formaldehyde novolac resin (PN) and a reactive 2-(6-oxid-6H-dibenz〈c,e〉〈1,2〉oxa-phosphorin-6-yl)chloride (ODC) while ODC was synthesized through reaction between o-phenylphenol 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. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1636–1644, 20000Comments 40Citations
- [Show abstract] [Hide abstract] ABSTRACT: Novel flame-retardant curing agents for epoxy resins, [ODOPM–PN] and [ODOPM–MPN], were prepared from phenol formaldehyde novolac (PN), melamine-phenol formaldehyde novolac (MPN) and a reactive 2-(6-oxid-6H-dibenz〈c,e〉 〈1,2〉oxaphosphorin-6-yl)-methanol (ODOPM) while ODOPM was synthesized through the reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and formaldehyde. The compounds (ODOPM–PN and ODOPM–MPN) were used as flame-retardant hardener for o-cresol formaldehyde novolac epoxy (CNE) resin in electronic application. The thermal stability and flame retardancy were determined by thermal gravimetric analysis and UL 94 vertical test. The glass transition temperatures were measured by dynamic mechanical analysis. The phosphorus–nitrogen synergistic effect on flame retardancy combined with the rigid structure of ODOPM have resulted in better flame retardancy, higher glass transition temperature and thermal stability for the phosphorus–nitrogen containing epoxy resin system than the regular phosphorus-containing flame retardant epoxy resin system. UL 94-VO rating could be achieved with a lower phosphorus content of as low as 0.81% with 2.36% nitrogen for the ODOPM–MPN cured epoxy resin system and no fume and toxic gas emission were observed.0Comments 141Citations