Conductive Compounds

C-200 is a unique, electrically conductive carbon filled ink utilising a vinyl based thermoplastic binder. C-200 is designed for screen printing in flex and additive circuit applications such as membrane switches. C-200 is tough, scuff resistant and has excellent adhesion to both treated Mylar and Kapton substrates. Crease resistance is outstanding when used on these substrates. C-200 is not recommended for use on Indium Tin Oxiode (ITO) sputtered surfaces.

C-200 is designed to give a good balance between long open time in screen printing operations and short drying time. Conductive Compounds Inc can adjust the rheology of C-200 to allow for more open time or quicker drying in order to accommodate different screening and drying operations. C-200 can be blended with AG-800 silver filled inks for specific resistance values and is compatible with UV-2507 dielectric. It is suitable for screen printing traces and discrete resistance pads and as an overprint for silver conductive traces.

TYPICAL PROPERTIES

Appearance: Thixotropic Black Coloured Paste
Viscosity
Brookfield #7RH spindle, 20 rpm: 40,000 cps
Brookfield #7RH spindle, 2rpm: 10,000 cps
Thixotropic Ratio: 4.0
Drying Schedule: <5 minutes @ 290°F (May be longer or shorter depending upon heat source and air flow)
Shelf Life: 6 Months in unopened container
Total % NV Solids: 33% ±2%
Hegman Gage: <100.0 µ
Volume Resisivity (ref ASTM D-257): 0.5 ohms-cm
Surface Resistivity: 50 ohms/Square

Conductive Compounds Inc offers custom formulating to tailor this material to your application.

APPLICATION GUIDELINES

For screening, a monofilament polyester (157 to 200 mesh) or a stainless steel (165 to 325 mesh) screen is recommended, with emulsion thickness between .001" and .004". A polyurethane squeegee with a Shore 'A' durometer between 60 and 70 is recommended. Always mix ink thoroughly before using, as carbon will settle quickly to the bottom.

For thinning and cleanup, use butyl cellesolve acetate or dibasic ester solvents. If faster drying time is required, contact us for solvent recommendations.

If solvent based inks are left on screens for any length of time, the ink will gradually thicken as solvent evaporates. If ink is to be left on an inactive press for any length of time, solvent evaporation can be minimised by pooling the ink into a small area instead of leaving it spread out over a large area. Pooling the ink reduces the surface area, thus slowing the drying process. Always check the viscosity of ink that has been recovered from a screen and add small amounts of solvent while mixing thoroughly to restore viscosity. Solvent can be added to reclaim thickened ink as long as the ink has not dried and hardened completely.

It is essential that all residual solvent be removed from this ink once it is applied. Incomplete drying will cause the ink to appear dry on the surface while trapping solvent underneath the surface. Over time, this trapped solvent will migrate out of the ink and can cause adhesion problems with any material (such as dielectrics) applied over the ink.

To check completeness of drying, evaluate the point to point resistance along one of the screened conductive paths after one pass through the drying oven or one cycle in a batch drying oven. Run the substrate through another drying cycle. Measure the point to point resistance again along the same path and compare it to the original reading. If the resistance decreases by less than 10%, then the ink is essentially dry after the first drying cycle or pass through the oven. If the resistance decreases by more than 10%, then more drying time is required to completely remove the solvent.

When blending C-200 ink with AG-800 silver ink for specific resistance ranges, be sure to mix the materials thoroughly before screening.

-------------------------------------------------------------------------------------------------------------------------------------------------------------------

The above guidelines are intended to provide a starting point for evaluation. Conductive Compounds Inc recognises that each customer's manufacturing process is unique and we can customise the rheology of C-200 to conform to the process parameters. We are also available to provide on-site technical assistance to resolve your processing issues. Call us to discuss your application in more detail.

NOTE: Although the above properties are accurate to the best of our knowledge Conductive Compounds Inc makes no guarantees for customer specifications established in applications where this product is used. Customer assumes responsibility for determining fitness of use in their particular application.