Basf Aktiengesellschaft

Frank P Woerner

Harald Mahnke

Heinz Weber

Guenter Kreibiehl

Peter Neumann

Gerhard Turznik

Hanshelmut Kaeppel

Klaus Ebel

Dieter Horn

Horst Reimann

Heinz Berbner

Hans D Zettler

Georg Falkenstein

Josef Lamprecht

Bernhard Seid

Friedrich Kraus

Michael Kuczaty

Eduard Heim

Peter T Kan

The continuous preparation of melamine/formaldehyde precondensate solutions is carried out by a process in which melamine, formaldehyde and, if required, modifiers and/or additives are metered into a continuous mixer, and the homogeneous mixture is passed into a single-screw or twin-screw extruder, condensed at elevated temperatures, cooled and extruded.

Continuous preparation of aqueous melamine/formaldehyde precondensate

Resilient foams based on melamine resins are prepared by foaming an aqueous solution which contains a melamine/formaldehyde precondensate, an emulsifier, a volatile blowing agent and a curing agent and then curing the foam. In this process, from 0.2 to 4% by weight of an alkali metal, alkaline earth metal or aluminum salt of an organic, preferably polybasic acid, of a polyphosphoric acid or of a boron acid are added to the aqueous solution.

Preparation of resilient melamine foams

A resilient foam, based on a melamine-formaldehyde condensate, which exhibits a number of important performance characteristics, namely:

Resilient foam based on a melamine-formaldehyde condensate

Stabilized melamine resin foams contain, as a stabilizer, a copper or iron compound in an amount corresponding to from 10 ppm to 3%, based on the weight of the melamine resin, of Cu or Fe, preferably an oxide, hydroxide or carbonate of copper.

Stabilized melamine resin foams

A process for the manufacture of a resilient foam based on a melamine-formaldehyde condensate, wherein an aqueous or alcoholic solution or dispersion containing a melamine-formaldehyde precondensate, an emulsifier, a blowing agent and a hardener is foamed by ultra-high-frequency irradiation and the foam is hardened by crosslinking the precondensate. The foam may be employed for heat and sound insulation, and as a packaging material.

Manufacture of resilient foams based on a melamine-formaldehyde

Storage-stable, liquid, only slightly colored polyisocyanates possessing carbodiimide groups and having an isocyanate content of from about 25 to 35% by weight, based on total weight; these products are obtained by condensing polyisocyanates in the presence of phospholines, phospholidines and/or their oxides, and stopping the condensation and stabilizing the condensation products with the Lewis acids, aromatic carboxylic acid halides, aromatic sulfonic acid esters and/or alkyl sulfates.

Storage-stable, liquid polyisocyanates possessing carbodiimide groups,

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Frank P Woerner