Epoxy resin Flame test

Composite-Based Laminates. Grade CEM-1 are laminates with continuous-filament glass cloth surfaces and a cellulose core, all with a flame-resistant epoxy resin binder. With good punching practice, sheets up to and including 2.4 mm (0.094 in.) in thickness may be punched at temperatures not less than 23°C (73°F). These laminates meet UL94 V-0 when tested in accordance with UL94. 

The electronics industry desires improved flame suppressant additives for microelectronic encapsulants due to bromine induced failure. Epoxy derivatives of novolacs containing meta-bromo phenol have exhibited exceptional hydrolytic and thermal stability in contrast to standard CEN resins with conventional TBBA epoxy resins. When formulated into a microelectronic encapsulant, this stable bromine epoxy novolac contributes to significant enhancements in device reliability over standard resins. The stable bromine CEN encapsulant took about 30% more time to reach 50% failure than the bias pressure cooker device test. In the high temperature storage device test, the stable bromine CEN encapsulant took about 400% more time to reach 50% failure than the standard compound. Finally, the replacement of the standard resins with stable bromine CEN does not adversely affect the desirable reactivity, mechanical, flame retardance or thermal properties of standard molding compounds. 

An effective flame-retardant for filled epoxy resins is alumina trihydrate. The burning rate and burning time after ignition, according to ASTM D 635 (cf. Section 3.1.5.2), for a basic epoxy resin and for its filled grade with 60 per cent of alumina trihydrate are plotted against the test temperature in Figure 5.11. 

The use of organically modified clay as a filler in epoxy resin nanocomposites have been shown to have a low flammability rating in the UL 94 test [13]. High levels of clay improved the flame resistance appreciably [17]. 

Hergenrother et al. have calculated the flaming combustion efficiency of epoxy resins prepared from various epo>y- or amine-functional organo-phosphorus compounds by dividing the EHC measured in fire calorimetiy tests (Ohio State University apparatus and cone) by the effective heat of complete combustion measured in a PCFC. The combustion efficiency ranged roughly from 0.6 to 0.8 versus 0.7 for the phosphorus-free epo)y resin) whatever the oxidation state of phosphorus and other parameters. The authors concluded that there is no discernible effect [...] on the combustion efficiency in the flame . 

Nevertheless, some authors have provided some evidence of a flame inhibition effect of phosphorus. Schartel et al. have measured the EHC of epo y resins in a PCFC i.e. corresponding to complete combustion) and in a cone calorimeter. Epojy resins containing DOPO covalently linked to the network have been studied. All thermosets exhibited the same EHC in a PCFC (approximately 24 kJ g ), but in cone calorimeter tests the composites prepared from the phosphorus-containing resins (with 60 vol% of carbon fibers) exhibited a significantly lower EHC than the composite prepared from the phosphorus-free epoxy resin. In this study, a clear flame inhibition effect was evidenced. 

Packaging of the chip portion of the chip/lead combined unit into a plastic or ceramic container is a semi-automated process involving the use of epoxy resins, usually epoxy novolak resin formations [15]. These should be fully cured prior to use, but unreacted monomers may be present, which can sensitise, as may other diluent and flame retardant materials, such as halogenated derivatives of bisphenol A, which are added to the resin prior to use. The completed devices are then laser marked in an enclosed system and tested, again in an automated process, prior to delivery for sale. 

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