Bectron^® PK 4340 is a one-component resin system which cures to form a soft polyurethane duroplastic. It comprises a liquid polyol system with a dispersed solid encapsulated polyisocyanate and a pigment combination selected to provide controlled rheology including excellent thixotropic properties. Heating the resin releases the encapsulated polyiso- cyanate resulting in a polyaddition reaction to give a resistant duroplastic cured material.

In contrast to the usual 2 component resin systems Bectron^® PK 4340 is ready to use and distinguished by excellent properties and especially good environ- mental compatibility.

APPLICATIONS 

• The cured Bectron^® PK 4340 is a soft duroplastic suitable for vibration protection of delicate compo- nents.
• Bectron^® PK 4340 is therefore well suited for the partial or selective coating of SMD and other compo- nents groups on printed circuit boards and ceramic substrates. The rapid increase of viscosity at low shear allows small areas of components to be pro- tected individually.
• Bectron^® PK 4340 can be applied as a dam around an area requiring thicker coating to be filled by a low- er viscosity grade such as PK 4342.