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Bakelite Phenolic resins pellets are synthetic polymers formed as condensation products of phenols and aldehydes by acid-catalyzed. In acid, the reaction forms novolac resins. These resins require a curing agent - often hexamethylenetetramine or hexa.They are not heat-sensitive.
Pellets Bakeite Phenolic Resin for Foundry Resin Coated Sands
Process Method
Hot Coating
The washed and dried silica sand is heated to 120–150℃. The
granulated phenolic novolak resin , with a melting point of around
80–100℃, is added to the mixer at 1–5% resin (based on sand and
depending upon application). It melts and coats the grains of sand.
The quantity of HMTA required for later curing of
the resin is then added as an aqueous solution (25–40% solids).
Sufficient hexa solution to both cool the sand and deliver the
correct amount of curative is added.The hexa level is 15–20% on the
basis of resin, depending upon the desired properties. The cooling
effect produced by the addition of the water solution prevents
premature curing of the binder, although it is possible that some
degree of cure occurs. Additives such as calcium stearate are
incorporated during this stage of the coating operation.
Specification:
Properties | Value | Test standard |
Curing time @150°C | 30-35s | GB/T24411-2009 |
Soften point | 90-92 | GB/T24411-2009 |
Free-phenol | 3.5%max | GB/T30773-2014 |
Appearance | light yellow granular | GB/T24411-2009 |
Packing&Storage
the package is paper-plastics bag in 25KGS each one
The storage life of this product is several months in a cool and
dry place in original closed bags