New flame‐retardant epoxy resin compounds containing novolac derivatives with specific aromatic compounds have been developed. After crosslinking reactions between epoxy resin and hardener, the epoxy resin compounds formed highly flame‐retardant network structures that were obtained by including biphenylene and phenylene moieties in the main chains of novolac‐type epoxy resin and phenol novolac resin hardener. The high flame retardancy is due mainly to the stable foam layers that form during combustion because of the low elasticity at high temperatures and the high pyrolysis resistance of the compounds. Furthermore, the addition of excess phenol derivative hardener not only facilitates the formation of the foam layers by decreasing the crosslink densities but also reduces the amount of flammable substances generated from the epoxy resin compounds during combustion. The use of a multifunctional epoxy resin containing four glycidyloxy groups in the compounds improved characteristics such as heat resistance and strength at high temperatures, while maintaining excellent flame retardancy. Copyright © 2001 John Wiley & Sons, Ltd.

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The flame retardancy and heat resistance of a phenol‐biphenylene‐type epoxy resin compound, which forms a self‐extinguishing network structure, were increased by the inclusion of a benzoguanamine‐modified phenol biphenylene resin. The benzoguanamine‐modified phenol biphenylene resin contains a benzoguanamine unit to release non‐flammable nitrogen substances during ignition and to increase the resin's reactivity toward epoxy resins, and biphenylene units to keep the resin's thermal degradation and water resistance. The addition of the benzoguanamine‐modified phenol biphenylene resin in the epoxy resin compound improved the epoxy resin compound's flame retardancy and heat resistance, and also increased its glass transition temperature while maintaining its water resistance and mechanical properties. Copyright © 2003 John Wiley & Sons, Ltd.

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The impact strength of cellulose diacetate (CDA) bonded with a modified cardanol (3-pentadecylphenoxy acetic acid: PAA) was greatly improved up to 9 kJ/m 2 by adding a relatively small amount of modified silicones while suppressing a decrease in bending strength. In our recent research, this thermoplastic resin (PAA-bonded CDA) exhibited high rigidity, glass transition temperature, and water resistance. However, its impact strength was insufficient for use in durable products. Therefore, silicones modified with polyether, amino, and epoxy groups were investigated as possible ways to improve the impact strength. The results show that adding polyether-modified silicone (polyether silicone) with moderate polarity relative to PAA-bonded CDA resulted in shearing deformation greatly enhances its impact strength while maintaining other properties, including glass transition temperature (T g ), water resistance, and thermoplasticity.

ABSTRACT:Highly flame-resistant glass-epoxy laminates without flame-retarding additives such as halogen and phosphorous compounds have been developed to overcome environmental problems caused by these additives. The laminates consist mainly of a self-extinguishing epoxy-resin compound (phenol aralkyl), an incombustible-gas generator (amino-triazine-novolac hardener: ATN hardener), and inorganic materials such as a charring promoter (zinc molybdate on talc: ZMT) and a limited amount of harmless metal hydroxide (aluminum trihydroxide: ATH). They are highly flame-resistant and have other beneficial characteristics, including soldering-heat resistance, humidity resistance, electronic properties, and processing advantages. These qualities make them applicable enough to replace the FR-4 type printed wiring boards (PWBs) that are widely used today. Simultaneously using the ATN hardener and ZMT in the laminates, including the epoxy-resin compound and ATH, greatly improved their flame retardance. We then reduced the amount of ATH to obtain even better flame retardance in the laminates. This reduction of the ATH, consequently, improved other practical characteristics such as solderingheat resistance, humidity resistance, and electronic properties.