Mowital® for ceramics
Mowital® is the trademarks for a wide range of different polyvinyl butyrals (PVB) marketed by Kuraray Europe GmbH. Mowital® has excellent adhesion and film-forming properties, high binding power and outstanding optical transparency. It is soluble in many organic solvents and can be combined with a wide range of reaction partners.
Based on these characteristics Mowital® grades are outstanding temporary binders for the manufacture of high performance ceramics to be used in solide oxide fuel cells, piezo ceramics, substrates or low temperature co-fired ceramics, and in passive components such as capacitors, inductors or resistors. Its extremely low ion content makes Mowital® most suitable for these special applications. In addition, Mowital® grades are suitable as temporaray binders for the production of conductive pastes, which can be used in the screen printing process.
During the sintering process, Mowital® combusts with virtually no residue at temperatures between 350 and 550°C. Furthermore Mowital®-based ceramics sinter with uniform shrinking behaviour.
PVB for Metal Pastes
Mowital® can be used as binder to make thick film pastes. Basically all Mowital® grades are suitable. Typically recommended are medium to high viscous grades to obtain pastes to be used for screen printing. Mowital® is acting as binders having already dispersing properties for the conductive metals. Mowital® is yielding pastes and thick films which can be co-fired with green tapes in laminated ceramic substrates like multilayer ceramic capacitors (MLCC’s).
Using Mowital® as binder for both, the ceramic green tapes and thick films gives best compatibility during co-firing. Good dimensional stability before and after firing is observed.
Mowital® – Multiple functions in tape casting processes
Mowital® is a temporary binder especially suitable for the manufacture of high performance single and multi layer ceramics. Within multi layer processes the polymer exhibits various important functions. It is compatible with organic substances used in ceramic slurries. The polar as well as a-polar chemical structure of Mowital® enables to produce flexible green tapes with high tensile strength and good elongation behaviour that can be lifted from launching materials such as PET films or metal without damage. During laminating in multi layer processes Mowital® supports the fusion of green tape layers. At burning temperatures between 350 and 440 °C Mowital® combusts with virtually no residue. In addition, Mowital®-based ceramics display a uniform shrinking behaviour.
- excellent dispersion of ceramic particles
- soluble in organic solvents
- excellent film formation
- fast solvent release
- good green sheet stabilization
- burns out residueless
- Ceramic made by solvent-based processes (Tape-cast processes for MLCC, alumina substrates)