Abstract: Described are laminate materials with syntactic cores sandwiched between outer layers. These laminates, which may be very thin, are ideally suited to use in high-stress applications, such as the casings for consumer electronics. The layered structure of an outer layer with a core provides improved strength and durability compared to a single layer material. The addition of a filler, such as microspheres, to the core material allows for adjusting the density, strength, and other material properties of the composite laminate to better suit a particular application.

Abstract: A fiber reinforced resin matrix composite material repair system is provided, which critically employs a resin comprising a catalyst of the formula I: ##STR1## with a multifunctional epoxy resin, the resin system being sealed in a water-proofed environment prior to being coated onto a fiber reinforcement. The coated fiber reinforcement is applied over the damaged area, the damaged portion having been removed, and the surrounding surface smoothed. An adhesive is applied to the remaining surface, prior to application of the patch. The resulting patch, which may further include thermoplastic toughening agents and an enhancer, can be directly cured at temperatures below 212.degree. F. to give physical properties similar to the original material.

Abstract: A fiber reinforced resin matrix composite material repair system is provided, which critically employs a resin comprising a catalyst of the formula I: ##STR1## with a multifunctional epoxy resin, the resin system being sealed in a water-proofed environment prior to being coated onto a fiber reinforcement. The coated fiber reinforcement is applied over the damaged area, the damaged portion having been removed, and the surrounding surface smoothed. An adhesive is applied to the remaining surface, prior to application of the patch. The resulting patch, which may further include thermoplastic toughening agents and an enhancer, can be directly cured at temperatures below 212.degree. F. to give physical properties similar to the original material.

Abstract: Foamable resin compositions of cyanate esters and thermoplastic resins are disclosed.

Abstract: A matrix resin system, for the preparation of composite parts, is comprised of a major amount of cyanate resin and an epoxy resin modified by reaction with an isocyanate. The resin system can be toughened by the addition of thermoplastic material, the toughness improvement being enhanced by the addition of a polyester rubber additive. The modified epoxy resin system is itself a resin having good modulus and Tg characteristics. The resin is cured at temperatures of 250.degree.-400.degree. F. in the presence of a metallic complex catalyst, and OH donor.

Abstract: A composite tooling part having excellent dimensional stability, which may be prepared at low cost employs a one-component epoxy resin system having a catalyst which is the reaction product of an aromatic dicyanate and an imidazole. Reinforcing materials are incorporated in the matrix, and the resulting prepreg is allowed to cure at low temperature, down to about room temperature, until the free standing state is obtained. Thereafter, if elevated temperature performance is necessary, the product can be post-cured at elevated temperatures, without the need for a high temperature master.

Abstract: A latent catalyst for epoxy resin systems is produced by the reaction between an aromatic dicyanate and imidazoles. The catalyst provides good curability, excellent mechanical properties, and remarkably extended shelf life. It also allows curing at room temperature.