Abstract: Increased elasticity of a laminate is obtained by adding 5-20% by weight of a blocked polyetherurethane component from a reaction product of polyethylene glycol, polypropylene glycol and p-nonylphenol with toluene-2,4-diisocyanate having the following composition:______________________________________ polyethylene glycol 15-20% by weight polypropylene glycol 50-60% by weight toluene-2,4-diisocyanate 8-12% by weight nonylphenol 10-15% by weight ______________________________________in the manufacture of a fire resistant laminate based on a cellulose-containing substrate material and an impregnating varnish made up of a phenol-resol with additives of plasticizers and flame retardants. A copper-laminated hard paper made of this phenolic resin laminate is distinguished by reduced punching resistance and stripping resistance.

Abstract: A process for the preparation of hard paper involves impregnating lengths of cellulose-containing material with plasticizer-containing mixture of a phenol-resol resin solution and cresol-resol resin solution according to a one-step method, subsequent drying, and then hardening of the resin-impregnated paper. The impregnating solution employed is a mixture of a 50-80% by weight phenol-resol resin solution with a 40-70% by weight cresol-resol resin solution, to which has been admixed, before impregnation, a plasticizer and additional water. The water is added in amounts of 4-12% by weight, based on the sum total weight of solid resins and plasticizer in the total solution mixture.

Abstract: A base material for the production of printed circuits according to the additive method includes a laminate base made up of laminated-together core sheets impregnated with hardenable resin, and a cover layer made up of a substrate sheet preimpregnated with phenolic resol resin and provided with an adhesive layer of an elastomeric polymer. The preimpregnated substrate sheet is also provided with a further resin impregnation containing a self-crosslinking copolymer of acrylic monomers and up to 30% by weight of a hardenable phenolic resol resin.

Abstract: The inclusion of metal particles finely and essentially statistically distributed in an insulating-material body which can be coated with a metal without use of an electric current is described wherein a solution of a reducible metal compound of a metal of Group VIII or Ib is employed. The solution can be added to a resin impregnating solution for the insulating material or to the adhesive of one or more adhesive layers in the insulating material. The solution of metal preferably contains a small amount of ammonium chloride.

Abstract: A formed epoxy resin composition comprising a condensed epoxy resin and pentabromodiphenylether; the use of pentabromodiphenylether alone or with other brominated diphenyl ethers as a flame-retardant agent for compositions containing epoxide resins especially fibrous substrates of glass and/or cellulose fibers containing epoxide resins therein.

Abstract: A process for producing nonflammable laminated materials which includes the steps of impregnating a cellulose-containing material with an impregnating solution containing a phenolic-resol resin solution, at least one plasticizer for the resin and optionally flameproofing agents, subsequently drying the impregnated material to effect preliminary condensation of the resin and thereafter curing superimposed layers of the impregnated and preliminary condensed material by the application of heat and pressure. The phenol-resol resin solution used contains 50-80% by weight of an ammonia alkaline-condensed phenol-resol resin with a solids content of 65-80% by weight and with a molecular weight distribution determined by gel chromatography of: dimers 20-26%; tri- and tetramers 6-12%; penta- and oligomers 24-36%; expressed in percent per unit area and hexamethylenetetramine in amounts of 1-15% by weight based on the weight of the impregnating solution.

Abstract: As an improved flame-resistant agent, pentabromodiphenyl ether and mixtures of pentabromodiphenyl ether and brominated diphenyl ethers; an agent for impregnating a mass of particles which comprises an impregnating agent, pentabromodiphenyl ether, preferably together with a plasticizer; a laminate substrate comprising a web of fibers impregnated with an impregnating agent and pentabromodiphenyl ether, said web preferably containing a plasticizer; a method of increasing the flame resistance of a continuous web impregnated with an impregnating agent which comprises including in said web pentabromodiphenyl ether.

Abstract: A laminated material comprises a substrate material containing resin-impregnated layers, a metal foil disposed on said substrate and an arc-retardant layer arranged between the metal foil and the substrate material. The arc-retardant layer is an arc-retardant, crosslinked heat-stable synthetic resinous material consisting of from about 60 to 100% by weight of a heat-stable resin which is free of aromatic groupings or heterocyclic rings containing at least one heteroatom and conjugated double bonds and which is not converted to a graphite-containing structure upon being thermally decomposed.