Siemens Aktiengesellschaft

Helmut Markert

Wolfgang Rogler

Klaus Kretzschmar

Lothar Schoen

Bernhard Stapp

Michael Schreyer

Wolfgang Von Gentzkow

Klaus-Robert Hauschildt

Wolfgang Bendel

Peter Donner

Christian Weitemeyer

Heiner Bayer

Wolfgang Kleeberg

Dietmar Wewers

Hans-Joachim Henkel

Peter Braun

Armin Datz

Wolfgang Roth

Volker Muhrer

Friedrich Alber

Manfred Schmiedel

Gerhard Piecha

Klaus M&uuml;ller

Hans Hauschildt

Goetz-Robert Koerner

Wolfgang Kautek

Gu/ Nter Mennig

Oliver Eitel

Maximilian Hodl

Klaus Kretzschman

In a process for the production of a flame-resistant, pourable, latently reactive, phenolically curable epoxy resin molding material for the encapsulating of electronic components, a latently reactive prepolymer epoxy resin mixture in powder form which is free of isocyanate groups is produced at reaction temperatures up to 200&deg; C. from a thermally polymerizable, filler-containing reaction resin mixture of polyepoxy resin consisting of a mixture of bi-functional and multi-functional epoxy resins and polyisocyanate resin having a molar ratio of the epoxy groups to the isocyanate groups of >1:1 with a substituted imidazole as reaction accelerator in a concentration of 0.5 to 2.5% by weight, relative to polyepoxy resin, and the prepolymer epoxy resin mixture is mixed with a powdered filler-containing phenolic resin mixture in a molar ratio of the epoxy groups to the phenolic hydroxyl groups of 1:0.4 to 1:1.1.

Blending epoxy resin-polyisocyanate-filler mixture and phenolic resin-filler mixture for molding

Oxazolidinone structures-containing prepolymeric epoxy mixture

Oxazolidinone structures-containing prepolymeric epoxy resin mixture

In a process for coating or bonding electronic components and subassemblies with reaction resin mixtures that are stable in storage at room temperature as a one-component system for several months, reaction resin mixtures are used, which contain the following components:

Process for coating or bonding electronic components and subassemblies

The invention relates to isocyanurate-containing, organosilicon compounds of the general formula ##STR1## in which Q=--(CH.sub.2).sub.3 SiR.sub.2 O(SiR.sub.2 O).sub.n SiR.sub.2 R', n is an integer from 0 to 25 and x is an integer from 0 to 10, and the following holds for the residues R and R', which can be the same or different:

Preparation of isocyanurate-containing organosilicon compounds

Isocyanurate-containing organosilicon compounds

The invention provides a method for generating thin layers on a silicon base having a high purity, thermal stability and good dielectric properties wherein non-functionalized organosiloxanes with alkyl groups or alkyl and aryl groups are photochemically polymerized and/or cross-linked by means of pulsed laser radiation with a wavelength of less than 400 nm where the pulse duration is 10 ps to 1 ms, the pulse frequency is 1 Hz to 10 KHz and the energy density is at least 1 J/cm.sup.2 and the irradiation takes placed with one or more pulses. The layers can be used as passivating and insulating layers for semiconductor components and circuits.

Method for generating thin layers on a silicone base

Optical glass fibers are provided with a primary coating of organo-polysiloxanes, containing acrylic acid ester groups, corresponding to the general formula: ##STR1## where the primary coating is free of inert components capable of migration.

Optical glass fiber with a primary coating of acrylic acid ester

A method for radical cross-linking or organic polymers, is disclosed which uses a cross-linking enhancer of the following formula ##STR1## wherein R is alkenyl or alkynyl;

Method for radical cross-linking of organic polymers

This invention relates to a method for the manufacture of molded material for an insulating component made of a quick-hardening reaction resin which employs a hardening catalyst. An object of the invention is to provide reaction resins which allow the manufacture of molded materials with increased dimensional heat resistance and at the same time, good mechanical properties. According to the invention, a reaction resin mixture of a polyepoxide and a polyisocyanate (EP/IC resin) with a formula mole ratio EP:IC of about 1 to 5 and a viscosity of up to about 7000 mPa.multidot.sec (at 25.degree. C.) is cross-linked under pressure by means of a tertiary amine or imidazole hardening catalyst at a gelling temperature of about 130.degree. to 150.degree. C. and is post-hardened at a temperature of 150.degree. to 200.degree. C. This produces a reaction resin molded material (OX/ICR molding material) containing oxazolidinone and isocyanurate rings with a mole ratio OX:ICR greater than 1 and, after hardening, the reaction of the epoxy and isocyanate groups of the EP/IC resin, is above about 90%.

Method for the manufacture of molded materials

Improved printed circuit boards of laminated thermosetting sheets with epoxy resin as the bonding agent contain for inhibiting copper migration 0.1% to 10% N,N'-bis-salicyloyl hydrazine, based on the weight of the hardened epoxy resin.

Printed circuit boards of laminated thermosetting sheets

The invention relates to a heat-hardened molded material produced from a resin mixture of a polyfunctional epoxide, a polyfunctional isocyanate and a reaction accelerator, which optionally contains additives and/or fillers. The objective is to make a resin mixture which permits the manufacture of a highly heat-resistant molded material, and which has at the same time a high-temperature cycle resistance and good mechanical properties. For this purpose, the polyfunctional epoxide of the resin includes a polyoxyalkylene glycol polyglycidyl ether.

Heat-hardenable reaction resin mixtures for impregnating and embedding

The invention relates to a method for impregnating and embedding electrical windings, especially coils of transformers, by means of an impregnating or casting resin based upon polyepoxide-polyisocyanate mixtures in the presence of a reaction accelerator latent at the processing conditions, which employs conditions that prevent the formation of gas and shrinkage voids in the cast in winding. To this end, the resin including, if applicable, additives, is dried at reduced pressure and while stirring at temperatures of up to 110.degree. C. and the winding is cast-in with the dried resin at reduced pressure and at temperature of up to 110.degree. C.; then the reduced pressure is removed and the winding is exposed to overpressure. Subsequently, generating by an elevated temperature in the electrical winding by Joule heat in the conductor, the cross-linking reaction of the resin is started and is controlled as a function of the reaction heat, until the winding is removed from the mold and post-hardened.

Method for impregnating and embedding electrical windings

This invention provides reaction resin molded materials (OX/ICR molded materials) containing oxazolidinone and isocyanurate rings prepared from reaction resin mixtures of polyepoxides and polyisocyanates (EP/IC resins) in the presence of a hardening catalyst and has as an object to provide a simple manufacturing method for heat resistant OX/ICR molded materials with improved mechanical properties. According to this invention, EP/IC resins which are capable of casting and impregnating and which are free from solvents are provided. These resins have a formula mole ratio of EP:IC of about 1 to 5 and a viscosity of up to 7,000 mPa sec at 25.degree. C. and are cross-linked by means of tertiary amine or imidazole hardening catalysts at gelling temperatures of up to 130.degree. C. and post-hardening temperatures of 130.degree. to 200.degree. C. to produce OX/ICR molded materials with a mole ratio OX:ICR greater than 1, wherein the reaction of the epoxy and isocyanate groups is above 90% after the hardening.

Method for the manufacture of reaction resin molding materials

The invention relates to heat-hardenable reaction resin mixtures which contain polyfunctional epoxides, polyfunctional isocyanates and a reaction accelerator as well as, optionally containing customary additives and/or fillers. The invention has the object of achieving reaction resin mixtures which are stable in storage, consist of individual components that are easy to mix, exhibit a prolonged prehardening period and permit at the same time the manufacture of materials which combine the good mechanical properties and the high temperature-cycle resistance of polyurethane structures with the good thermal properties of oxazolidinone and isocyanurate structures. According to the invention, the reaction resin mixtures contain as polyfunctional isocyanates, isocyanate prepolymerisates in the form of reaction products of diphenyl methanediisocyanate and a diol, or of an isocyanate mixture of diphenyl-methanediisocyanate and a polymethylenepolyphenylisocyanate (with a functionality greater than 2) and a diol. The prepolymerisates utilize 0.01 to 0.35 equivalents and preferably 0.05 to 0.2 equivalents of the diol per 1 equivalent of isocyanate; the mixture contains 0.2 to 5 equivalents isocyanate per 1 equivalent of epoxy. The reaction accelerator is a tertiary amine or an imidazole.

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Nuremberg, Germany

Helmut Markert