Cyanate/maleimide compositions

Numerous cyanate/maleimide compositions and the applications thereof have been described in Japanese patent applications. 

In several patents, the application of BPA/DC prepolymer in epoxide resin compositions is described [79, 81-84], This approach is similar of that mentioned in the chapter devoted to cyanate/maleimide compositions [62],... 

Instead of BPA/DC monomer, the corresponding prepolymer was heated with BMI to obtain a binder [62], In a similar composition, p-toluenesulfonic acid was used as the cyanate/maleimide prereaction catalyst. For the crosslinking stage Zn octoate was added [63], Both BPA/DC and BMI can be used in the form of prepolymers. The binder for copper clad laminates contains, moreover, a saturated polyester, Zn octoate and powdered fused quartz [64],... 

In addition to the two-component cyanate/epoxide, cyanate/maleimide and epoxide/ maleimide systems, numerous three-component compositions have been described in 34 Japanese and 2 FRG patent applications. The patent applications differ in curing agents, other additives and applications of the binders obtained. Sometimes the compositions mentioned in Sect. 4 above are given here again, differing in that a bismaleimide is added. 

As in the cyanate/epoxide compositions, polysulfone is used as an additive in cyanate/epoxide/maleimide systems. As an example, a composition for carbon-fiber composites should be mentioned. It contains BPA/DC-BMI prepolymer, epoxide resin and polyethersulfone [111-113] Zn acetate and dicumyl peroxide are added. Polyethersulfone powder was added to the three-component system with 4,4 -diamino-diphenylmethane-based tetraepoxide as one of the epoxy resins used [114]. 

The three-component cyanate/maleimide/epoxide compositions are mainly used as polymer matrix in copper clad laminates and in carbon fiber composites for engineering purposes. High heat resistance, water and solvent resistance, mechanical and impact strength is claimed. A composition for copper wire enamelling [121] and a resin for electric motor coil windings impregnation were described [107]. 

Solvent resistant laminates for printed circuits were manufactured by coating of copper foil with a solution of PPO, BPA/DC, bis(4-maleimidophenyl) ether and Zn octoate in toluene the coated foil was laminated with PPO-impregnated glass fabric [47]. Similar result was achieved by the modification of PPO with polyfunctional cyanates or maleimides, liquid polybutadiene and a polymerization catalyst [48], A solvent and heat resistant composition for printed circuits consists of copoly [(2,6-dimethylphenylene)-(2,3,6-trimethylphenylene)]oxide, maleic anhydride grafted poly-1,2-butadiene, bis(4-maleimidophenyl)methane, BPA/DC and toluene. BPA/DC prepolymer may be used instead of the monomer [49]. 

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