Technical Data Sheet PUC Polyurethane Coating Product Description PUC is a tough, flexible, modified polyurethane conformal coating and is specifically designed for the protection of electronic circuitry. PUC has excellent mechanical and dielectric properties. Features Excellent adhesion to a wide variety of substrates. Fluoresces under UV light for ease of inspection. Good resistance to a wide variety of chemicals including acids and alkalis. Wide operating temperature range. Can be soldered through without fear of highly toxic gases being produced (contains no isocyanates). Non-corrosive to Cadmium and Zinc plate (contains no phenols). Resistant to mould growth. Cured coating can be removed with Electrolube Electrolube remover gel (DRG). Excellent Dielectric properties Excellent mechanical properties including abrasion resistance Approvals MIL Approval (MIL-1-46058C): Meets approval RoHS Compliant (2002/95/EC): Yes IPC-CC-830 Meets approval DEF-STAN 59/47 Meets approval Liquid Properties Appearance: Clear amber liquid Specific Gravity (Density) 20C: 0.90 (Bulk), 0.870 (Aerosol) g/ml VOC Content: 63% (Bulk) 66% (Aerosol) Flash Point: 38C (Bulk), -4C (Aerosol) Solids content: 37% (Bulk), 34% (Aerosol) Viscosity 20C: 150 - 240 Centipoise (Bulk) Touch Dry: 40 - 45 minutes Recommended Drying Time: 24 hours 20C 180 minutes 65C 90 minutes 80C 2 2 Coverage 25m: 13m per litre (Bulk), 5m (400ml Aerosol) Dry Film Coating Colour: Clear amber Operating Temperature Range: -55C to +130C Flammability: Meets UL94-HB Thermal Cycling (MIL-1-46058C): Meets approval Coefficient of Expansion: 100ppm Dielectric Strength: 60 kV/mm Dielectric Constant: 3.6 15 Insulation Resistance: 1 x 10 Ohms/cm (DEF-STAN 59/47) Electrolube, A division of H K Wentworth, Kingsbury Park, Midland Road, Swadlincote, Derbyshire, DE11 0AN Tel: +44(0) 1283-222111 Fax: +44(0) 1283-550177 www.electrolube.com BS EN ISO 9001:2000 Certificate No. FM 32082 Page 1 of 3 Dissipation Factor 1MHz 25C 0.01 Moisture Resistance (MIL-1-46058C): Meets approval Description Order Code Shelf Life Packaging PUC Conformal Coating 400ml Aerosol PUC400 36 Months 5 Litre Bulk PUC05L 24 Months Polyurethane Thinners 5 Litre PTH05L 36 Months Removal Solvent 1 Litre DRG01L 36 Months Directions For Use PUC can be sprayed, dipped or brushed. The thickness of the coating depends on the method of application (typically 25 microns). Temperatures of less than 16C or relative humidity in excess of 75% are unsuitable for the application of PUC. As is the case for all solvent based conformal coatings, adequate extraction should be used (refer to MSDS for further information). Substrates should be thoroughly cleaned before coating. This is required to ensure that satisfactory adhesion to the substrate is achieved. Also, all flux residues must be removed as they may become corrosive if left on the PCB. Electrolube manufacture a range of cleaning products using both hydrocarbon solvent and aqueous technology. Electrolube cleaning products produce results within Military specification. Spraying Bulk PUC needs to be diluted with the appropriate thinners (PTH) before spraying. The optimum viscosity to give coating quality and thickness depends on the spray equipment and conditions, but normally a dilution ratio of 2:1 (PUC to PTH) is required. Suitable spray viscosity is typically 50-80 centipoise. If bulk coating material has been agitated, allow to stand until air bubbles have dispersed. PUC is suitable both for use in manual spray guns and selective coating equipment. The selected nozzle should enable a suitable even spray to be applied in addition to suiting the prevailing viscosity. The normal spray gun pressure required is 274 to 413 kPa (40 - 60 lbs/sq.inch). After spraying, the boards should be placed in an air-circulating drying cabinet and left to dry. Spraying - Aerosol When applying PUC in aerosol form care must be taken to ensure the can is not shaken before use. Shaking the can will introduce excessive air bubbles and will give a poor coating finish. The can should be held at 45, and 200mm from the substrate to be coated. The valve should then be depressed when the can is pointing slightly off target and moved at about 100mm / second across the target. To ensure the best coating results are achieved try to use a smooth sweeping motion with small overlap for successive rows. To ensure penetration of the coating beneath the components and in confined spaces, spray the assembly from all directions to give an even coating. After spraying, the boards should be placed in an air-circulating drying cabinet and left to dry. Electrolube, A division of H K Wentworth, Kingsbury Park, Midland Road, Swadlincote, Derbyshire, DE11 0AN Tel: +44(0) 1283-222111 Fax: +44(0) 1283-550177 www.electrolube.com BS EN ISO 9001:2000 Certificate No. FM 32082 Page 2 of 3