Florida Finishing Electromagnetic and Radio Frequency Shielding
SprayLat 599-B3755 Product Data Sheet
SILVER COATED COPPER CONDUCTIVE COATING
SERIES 599-B3755 is a new sprayable silver-coated copper conductive coating for use on plastic substrates. It is unique in that it is formulated in very mild solvents that can tolerate higher built-in stresses which can be found in molded parts, and provides effective shielding at less than 1.0 mil (25 microns) dry film thickness. The dried conductive film is extremely hard, tough and durable. 599-B3755 contains no methyl ethyl ketone (MEK) or other strong solvents which can attack solvent-sensitive substrates, such as polycarbonate and polycarbonate blends. It is designed with a fast drying solvent blend which is desirable in high volume production.
• Compatible with sensitive plastics because of mild solvents.
• Effective shielding at 1.0 mil (25 microns) dry film.
• Excellent film cohesion.
• "Zero Tolerance" for loose particles in the film.
• Passes U.L. requirements.
• Excellent adhesion to most plastic substrates.
• Excellent abrasion resistance.
• Supplied as a viscous liquid for reduced settling.
• Minimal overspray and dusting during application.
• No rub-off due to handling.
• Fast drying.
• Passes ASTM D-3359-97 adhesion test.
HVLP or standard air gun with fluid recirculation system is recommended. A pressure pot may be used provided that: (1) it has a large diameter, paddle type agitator to keep copper in suspension and (2) a short translucent MEK-resistant fluid line of 1/8" (3.15 mm) ID or smaller is used (such as Binks Synflex) to prevent settling in the Fluid line.
Although 599-B3755 is formulated in mild solvents, the user must test the compatibility on the actual molded parts to determine its suitability for any specific application.
The following application parameters should be followed for optimum properties:
1. Material should be stirred thoroughly before use.
2. Material should be incorporated into a recirculating system.
3. Pressure in the system should be adjusted to produce sufficient flow rates to ensure suspension of the metal.
4. The gun should be set as follows:
a. Completely shut off needle to the gun.
b. Slowly open needle to achieve a minimum wet film.
c. Adjust fan for part.
d. Readjust needle setting to ensure minimum wet coat.
By following the above procedures, a number of benefits will be achieved. The optimum minimum film thickness will result in minimum cost per part. The above techniques will produce a very smooth and bright appearance. Maximum conductivity will also be achieved.
Density & Viscosity: (@ 75 Degrees F +/- 3)
Percent Solids: 29 ± 1.5% by weight.
Density: 9.25 ± .5 lbs. per gallon.
VISCOSITY: The thixotropic properties of 599-B3755 during application can be
maintained by using a combination
of Ethyl Alcohol* and B-4045
(Super Mega Thinner) as the
diluent. The recommended viscosity
range at application is 8 - 18 seconds #4 EZ Zahn Cup. Our testing has shown that a viscosity of 13 seconds is ideal. Realize that a full range of custom viscosities can be created to satisfy any need.
The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. For liquids, it corresponds to the informal notion of "thickness". For example, honey has a higher viscosity than water.
Viscosity is due to friction between neighboring parcels of the fluid that are moving at different velocities. When fluid is forced through a tube, the fluid generally moves faster near the axis and very slowly near the walls, therefore some stress (such as a pressure difference between the two ends of the tube) is needed to overcome the friction between layers and keep the fluid moving. For the same velocity pattern, the stress required is proportional to the fluid's viscosity. A liquid's viscosity depends on the size and shape of its particles and the attractions between the particles.
A fluid that has no resistance to shear stress is known as an ideal fluid or inviscid fluid. Zero viscosity is observed only at very low temperatures, in superfluids. Otherwise all fluids have positive viscosity. If the viscosity is very high, for instance in pitch, the fluid will appear to be a solid in the short term. A liquid whose viscosity is less than that of water is sometimes known as a mobile liquid, while a substance with a viscosity substantially greater than water is called a viscous liquid.
In paint industries, viscosity is commonly measured with a Zahn cup, in which the efflux time is determined and given to customers. The efflux time can also be converted to kinematic viscosities (centistokes, cSt) through the conversion equations. A Ford viscosity cup measures the rate of flow of a liquid. This, under ideal conditions, is proportional to the kinematic viscosity.
Theoretical Coverage: (no application loss)
Also known as the "Spreading Rate". Theoretical Coverage is COMPUTED from @ 100% transfer efficiency. Including all reducer necessary to meet the Manufacturer Viscosity Recommendations as specified above.
98 sq. ft./gal @ 1.0 MIL DFT
100% transfer efficiency.
Surface Resistivity and Film Thickness: (OHMS per SQ & DFT)
Resistivity: Less than .015 ohm/square per 1.0 mil (12.5 microns) dry film.
These readings can be achieved under proper conditions: (1) properly mixed paint; (2) film is 100% dry.
There are several methods for measurement of Shielding Coating thickness and they fall into two categories. These categories are wet film and dry film coating measurements.
Florida Finishing measures all EMI/RFI Shielding by method of MEANS using a Calibrated Micrometer to determine the actual film thickness during a production run.
Coating Film Samples are retrieved from special Masking applied to production parts.
Test coupons are the ideal method for measuring the coating thickness, whether is it spraying or dipping, and can be kept as a physical record of the performance. Apply the coating to the test coupons at the same time as the circuit boards provides a permanent measurement and an accurate guide to the coating thickness.
MILS Dry: 1.0
Envoronmental & Drying:
Environmental No change in resistivity after 7-day Testing: exposure to 85°C. @ 85% R.H.
Note 1: Do not exceed the heat distortion temperature of the substrate.
DRYING TIME: 30 minutes flash off at room temperature; then 30 minutes @ 140°F. (60°C.)
Touch, Tack, Re-Coat, Force.
To Touch: 30 Minutes
To Handle: 90 Minutes
To Pack: Overnight (no poly bags)
To Force Dry: 30 Minutes at 140° F
Note: 599-B3755 can be sprayed as received, but a dilution of 4:1 by volume is recommended.
Reduce with a 50/50 blend of EA (Ethyl Alcohol) and MT (Mega Thinner B-4045).
NOTE: 599-B3755 dries rapidly. Keep container closed. If skins develop, do not attempt to dissolve - strain through a coarse filter. Clean equipment after each use. Ethyl alcohol can be used to clean equipment. If strong solvents are used, flush the system with ethyl alcohol before use.
1 Part Base to 0.25 Part Reducer
50/50 blend of EA (Ethyl Alcohol) and MT (Mega Thinner B-4045).
Nine (9) months from date of manufacture.
The total period of time beginning with the date of manufacture, or date of pack, and terminated by the date by which an item must be used (expiration date) or subjected to inspection, test, or disposal action.
Shelf-life is not to be confused with service-life (defined as, A general term used to quantify the average or standard life expectancy of an item while in use.)
From MFG Date. Based on Unopened container.
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