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AssigneeBayer Aktiengesellschaft
InventorsManfred Schmidt, Eberhard Bandtel, Walter Traudisch, Georg Spott, Dieter Freitag
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Boron containing phenol/formaldehyde resins can be isolated from their reaction media by evaporating said resins in a spiral flow evaporator which has a ratio between throughput and tube cross section from 0.1 to 1.5 and a ratio between throughput and evaporation surface from 100 to 400.
A process for isolating boron-containing phenol/formaldehyde resins from their reaction media which, in addition to the end product, also contains starting compounds and solvents used, characterised in that isolation is carried out by concentration through evaporation in a spiral flow evaporator which has the following characteristics:
Dependencies are inferred from the claim text.
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With acyclic or carbocyclic organic compounds: containing atoms other than carbon and hydrogen
Evaporating: evaporators with heating coils
Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping: with one or more auxiliary substances
Condensation polymers of aldehydes or ketones with phenols only: chemically modified polycondensates
Term ended 6 Nov 1999 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to a process for isolating boron-containing phenol/formaldehyde resins from their reaction media.
German Offenlegungsschrift No. 2,557,613 describes boron-containing phenol/formaldehyde resins which may be produced by partly reacting a novolak with boron compounds, accompanied or followed by reaction with unsaturated fatty acids.
These resins may be represented by the following general formula: ##STR1## wherein m and n which may be the same or different represent a value of from 1 to 2, with the proviso that
The approximately 75% by weight resin the receiver 1 heated to 80.degree.-120.degree. C., preferably to 80.degree.-100.degree. C., to the coiled reaction and evaporation tube 3 by the pump 2. After the pump but before the spiral flow evaporator, the temperature of the resin solution is 170.degree.-220.degree. C., preferably 190.degree.-210.degree. C., the pressure at the end of the spiral flow evaporator being adjusted to 50-500 mbars, preferably to 100-300 mbars. The resin melt concentrated by evaporation is pumped (by pump 5) from the cyclone 4 to a cooling stage and then to a suitable apparatus where it is prepared for processing (cooling roller or pelletising belt), while the solvent vapours are delivered to a condenser 6. The condensate is run off through the pipe 7. The pump 8 generates the vacuum.
The dimensions of the spiral flow evaporator used for carrying out the resin-isolating process according to the present invention which are dependent on the throughput and which are required for obtaining reinforcing resins of suitable, optimal quality are indicated by way of example in the following Table:
______________________________________ Throughput kg/h A B solution)(75% by weight resin ##STR3## ##STR4## ______________________________________ 40 0.226 190 100 0.25 200 1000 0.333 222 1330 0.333 240 ______________________________________