Conductive Compounds

AG-750 is a unique electrically conductive silver filled ink designed for screen printing in flex circuit, membrane switch, touch screens and other additive circuit applications. AG-750 is a low cost ink that has slightly higher electrical resistivity than our AG-500 silver ink. AG-750 is tough, scuff resistant and has excellent adhesion to most metal surfaces as well as polyester, polyimide and polycarbonate films. Crease resistance of AG-750 is outstanding when used on these substrates. Indium tin oxide substrates require the use of our AG-500 silver conductive ink. AG-750 utilises uses a solvent system that is essentially non-hazardous, non-flammable and non-toxic. AG-750 can be thinned with solvent for spraying or dipping for EMI/RFI shielding applications.

AG-750 is designed to give a good balance between long open time on screens and short drying time in subsequent drying processes. Conductive Compounds Inc. can adjust the rheology of AG-750 to allow for more open time or quicker drying to accommodate different screening and drying operations. AG-500 is compatible with UV-3201 and UV-1006 dielectrics, EP-600 two part conductive epoxy adhesive and UV-3010 component encapsulant and conformal coating.

AG-750 should not be blended with C-100 carbon resistive ink.

TYPICAL PROPERTIES

Appearance Thick Silver Coloured Paste
Viscosity
Brookfield #5 spindle, 2 rpm 21,000 cps
Brookfield #5 spindle, 20 rpm 11,000 cps
Thixotropic Ratio 1.9
Drying Schedule 10 to 30 minutes at 250 to 300°F.
(May be longer or shorter depending
upon oven heat profile and air flow.)
Shelf Life 6 months in unopened container
Total % NV Solids 50% +/- 2%
Hegman Gage <50.0 m
Volume Resistivity (ref. ASTM D-257) 4.0 x 10 -4 W-cm
On 5 mil Mylar 5.0 x 10 -4 W-cm
Surface Resistivity < .03 W/Square
Theoretical Coverage (Dried Film) 37m2/gallon/25m (400ft2/gallon/mil)

APPLICATION GUIDELINES

AG-750 will thicken when it is stored in sealed containers over a period of time. It is essential to mix the material thoroughly before use to redisperse any settled silver particles and to return the ink to a more flowable viscosity.

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.

For thinning and cleanup, use butyl cellesolve acetate or dibasic ester solvents. If faster drying time is required, contact Conductive Compounds Inc. 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.

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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 are available to provide technical assistance to resolve your processing issues. Call us to discuss your application in more detail.

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.