Abstract: A relay housing comprising a cover plate which is inserted in a step-shaped recess of a housing rim. The rim portion of the plate has a reduced thickness so that there is formed a rim channel between the plate and the housing rim. The channel is in communication with fill-in cavities in the cover plate through which the channel is filled with a self-hardening or curable material. The fill-in cavities are formed as flat recesses adjoining the rim channel with wide openings, not connected among each other, that are at least twice as large as the width of the rim channel. The bottom of the channel slopes downwardly from said openings. This arrangement permits a quick sealing by use of only small amounts of sealing compound.

Abstract: The invention provides mixtures based on resins containing allyl groups and being solid at room temperature, useful for the preparation of thermally stable, photo-crosslinkable layers and foils. According to the invention, such mixtures comprise triallylcyanurate prepolymers and/or triallylcyanurate precopolymers with compounds containing allyloxy and/or allylester groups, and compounds with at least one N-maleimide group, wherein the C.dbd.C double bond of the N-maleimide groups are bonded to hydrogen, hydrogen and chlorine or hydrogen and methyl radicals. Preferably, the N-maleimide C.dbd.C bonds carry hydrogen.

Abstract: Novel cyclic monomers leaving two functional groups capable of undergoing condensation reactions to form amide, urea or urethane linkages and at least one photo or radiation-reactive group are condensed with cyclic comonomers to form a soluble, substantially-linear condensation pre-polymer. A solution of the prepolymer is applied to a substrate and the solution is evaporated off to form a film or foil. The photo or radiation-sensitive layer or foil is exposed or irradiated through a pattern, the unexposed or unirradiated part is dissolved or stripped off, and the relief structure which remains is annealed if necessary. The relief structures obtained are distinguished particularly by the sharpness of their edges, good mechanical and chemical properties as well as good insulating properties. They are suited particularly for the preparation of miniaturized insulating layers.