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DOWSIL™ 1-2620 Low VOC Conformal Coating
- One-part silicone conformal coating
- Wide operating temperature range (-45°C to 200°C)
- UV indicator for inspection and process control
Product Description
DOWSIL™ 1-2620 Low VOC Conformal Coating is a one-part, solvent-borne silicone resin conformal coating designed for protective coating of rigid and flexible circuit boards and PCB system applications. It provides 350 cP viscosity, 80 Shore A hardness, and UV indicator support while supporting room-temperature moisture cure and optional mild heat acceleration after solvent flash-off. This makes it suitable for PCB assemblies requiring low-viscosity flow, dielectric protection, and abrasion-resistant coating performance, subject to application-specific testing and qualification.
Key features
- One-part silicone resin solution - supplied as a one-part conformal coating with no separate catalyst or hardener mixing step.
- Low viscosity - 350 cP viscosity supports flow and filling in narrow gaps and spaces on PCB assemblies.
- Moisture cure - cures at room temperature with a 15 minute tack-free time at 25°C and optional mild heat acceleration after solvent flash-off.
- Abrasion-resistant surface - cures to a firm elastoplastic coating with 80 Shore A hardness.
- Inspection support - contains a UV indicator to support visual or automated coating inspection.
- Recognized coating documentation - listed with UL 94 V-0, UL 746E, IPC-CC-830 Amendment 1, and MIL-I-46058C Amendment 7 in the supplied product data.
Applications
DOWSIL™ 1-2620 Low VOC Conformal Coating is suitable for electronics assemblies where low-viscosity silicone coating, circuit-board protection, and coating inspection are part of the application review.
- Rigid and flexible circuit boards: suitable for protective coating of printed circuit boards and PCB system applications.
- PCB assembly protection: supports environmental protection, corrosion resistance, and dielectric protection requirements.
- Narrow-gap coating areas: low viscosity supports flow and filling in tight spaces and complex board geometries.
- Thin-section encapsulation: suitable for thin protective coating applications where solvent-borne silicone flow is required.
Related resources
Technical Specifications
| General Properties | |||||
| Color Color The color | Translucent | ||||
| Specific Gravity Specific Gravity Specific gravity (SG) is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume. For liquids, the reference substance is almost always water (1), while for gases, it is air (1.18) at room temperature. Specific gravity is unitless. | 0.88 | ||||
| Physical Properties | |||||
| Viscosity Viscosity Viscosity is a measurement of a fluid’s resistance to flow. Viscosity is commonly measured in centiPoise (cP). One cP is defined as the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP. A product like honey would have a much higher viscosity -around 10,000 cPs- compared to water. As a result, honey would flow much slower out of a tipped glass than water would. The viscosity of a material can be decreased with an increase in temperature in order to better suit an application | 350 mPa.s | ||||
| Mechanical Properties | |||||
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| Electrical Properties | |||||
| Dielectric Strength Dielectric Strength Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material. Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property. As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow. | 16 kV/mm | ||||
| Volume Resistivity Volume Resistivity Volume resistivity, also called volume resistance, bulk resistance or bulk resistivity is a thickness dependent measurement of the resistivity of a material perpendicular to the plane of the surface. | 1.1x1015 Ohms⋅cm | ||||
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| Thermal Properties | |||||
| UL 94 Rating UL 94 Rating Flammability rating classification. It determines how fast a material burns or extinguishes once it is ignited. HB: slow burning on a horizontal specimen; burning rate less than 76 mm/min for thickness less than 3 mm or burning stops before 100 mm V-2: burning stops within 30 seconds on a vertical specimen; drips of flaming particles are allowed. V-1: burning stops within 30 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed. V-0: burning stops within 10 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed. 5VB: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may develop a hole. 5VA: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may not develop a hole | V-0 | ||||
Additional Information
DOWSIL™ 1-2620 Low VOC Conformal Coating
DOWSIL™ 1-2620 Low VOC Conformal Coating is a one-part, translucent, low-viscosity silicone resin solution for protective coating of rigid and flexible circuit boards and PCB system applications. It is designed for applications requiring a firm, elastoplastic, abrasion-resistant surface after cure, low-viscosity flow into narrow spaces, UV inspection support, and reduced VOC positioning compared with DOWSIL™ 1-2620 Dispersion.
Low-viscosity coating with inspection support
- One-part silicone resin solution for protective circuit-board coating.
- 350 cP viscosity supports flow and filling in narrow gaps and spaces.
- Translucent clear cured appearance supports visual review of coated areas.
- UV indicator supports manual or automated coating inspection.
- Firm, elastoplastic, abrasion-resistant cured surface with 80 Shore A hardness.
- Low-VOC version of DOWSIL™ 1-2620 Dispersion.
Room-temperature moisture cure
Product documents and Dow coating resources
Review the technical data sheet for typical product properties, the safety data sheet for handling and storage requirements, and the Dow conformal coatings selection guide for broader coating-family context.
Use the TDS to review typical viscosity, cure behavior, cured appearance, hardness, and agency listing information before process qualification.
Use the SDS for current hazard classification, PPE, ventilation, storage, disposal, and emergency-response information before handling the material.
Use the selection guide to compare DOWSIL™ conformal coating options by viscosity, cure profile, hardness, and agency listing context.
The Dow conformal coatings selection guide explains how silicone coatings are positioned by viscosity, cure profile, hardness, stress relief, abrasion resistance, UV inspection, and agency listing context. It also includes a solventless coating section for applications where reducing solvent-handling complexity is a key selection driver, along with comparison tables for solventless RTV, solventless heat-cure, and solvent-based RTV conformal coatings.
Solvent-based RTV conformal coating selection table
Use this compact comparison to review DOWSIL™ solvent-based RTV conformal coating options by viscosity, non-volatile content, tack-free time, hardness, inspection method, and documented agency listing context. The highlighted row shows where DOWSIL™ 1-2620 Low VOC Conformal Coating fits when reduced-VOC positioning and low-viscosity flow into narrow gaps are part of the application review.
| Product and positioning | Viscosity / non-volatile content | Tack-free time at 25°C | Typical hardness | Inspection | Compliance | Selection basis |
|---|---|---|---|---|---|---|
| DOWSIL™ 1-2577 Conformal Coating Medium-viscosity, firm, abrasion-resistant standard solvent-borne coating | 950 cP / 72% | 7 min | 80 Shore A / 20 Shore D | UV indicator | UL 94 V-0; UL 746E; IPC-CC-830; MIL-I-46058C Amendment 7 | Select when a medium-viscosity, UV-inspectable coating with a firm abrasion-resistant surface is required. |
| DOWSIL™ 1-2577 Low VOC Conformal Coating Reduced-VOC, lower-odor version of 1-2577; medium viscosity | 1,050 cP / approximately 34% | 6 min | 85 Shore A / 25 Shore D | UV indicator | UL 94 V-0; UL 746E; IPC-CC-830 Amendment 1; MIL-I-46058C Amendment 7 | Select when the performance profile of 1-2577 is required together with reduced VOC content and lower odor. |
| DOWSIL™ 1-2620 Dispersion Low-viscosity standard solvent-borne coating for thinner coating, greater coverage per kilogram, and faster dispensing | 150 cP / 59% | 5 min | 80 Shore A / 25 Shore D | UV indicator | UL 94 V-0; UL 746E; IPC-CC-830; MIL-I-46058C Amendment 7 | Select when very low viscosity, flow, thin coating, material coverage, or dispensing speed is the primary process requirement. |
| DOWSIL™ 1-2620 Low VOC Conformal Coating Reduced-VOC, lower-odor version of 1-2620 Dispersion; low viscosity | 350 cP / approximately 31% | 15 min | 80 Shore A | UV indicator | UL 94 V-0; UL 746E; IPC-CC-830 Amendment 1; MIL-I-46058C Amendment 7 | Select when reduced VOC content and enhanced flow into narrow gaps and spaces are required. |
| DOWSIL™ CC-2570 Conformal Coating Non-fluorescent, medium-viscosity coating for improved optical performance | 1,000 cP / 72% | 7 min | 76 Shore A / 25 Shore D | No fluorescence | UL 94 V-0; UL 746E | Select when fluorescence must be avoided and a medium-viscosity coating is needed. |
| DOWSIL™ CC-2571 Conformal Coating Non-fluorescent, very-low-viscosity coating for improved optical performance | 75 cP / 55% | 15 min | 80 Shore A / 25 Shore D | No fluorescence | UL 94 V-0; UL 746E | Select when fluorescence must be avoided and maximum flow from this product group is required. |
Process points to confirm before qualification
- Apply to clean and dry substrates.
- Review flux residues, oils, dust, and process contamination before coating.
- Validate adhesion on the actual PCB laminate, solder mask, metals, and component surfaces.
- Review spray, brush, flow, dip, or automated pattern coating for the actual line.
- Use the 350 cP viscosity together with target wet-film thickness and keep-out areas.
- Confirm coating flow around component edges, leads, solder joints, vias, and narrow gaps.
- Allow sufficient solvent flash-off before applying mild heat.
- Use tack-free time as a handling indicator, not as final property confirmation.
- Use the UV indicator to support coating-presence inspection, then separately verify film thickness, adhesion, and electrical performance.
- Review local coating removal by mechanical means or suitable solvents where appropriate.
- Clean and dry the affected area before recoating.
- Confirm repaired-area adhesion and coating continuity before release.
Where DOWSIL™ 1-2620 Low VOC fits
Frequently asked questions about DOWSIL™ 1-2620 Low VOC Conformal Coating
What is DOWSIL™ 1-2620 Low VOC Conformal Coating used for?
It is used as a protective conformal coating for rigid and flexible circuit boards and PCB system applications, particularly where toughness, abrasion resistance, dielectric protection, and low-viscosity flow are part of the application review.
How does this coating cure?
DOWSIL™ 1-2620 Low VOC cures by atmospheric moisture at room temperature. Mild heat can be used to accelerate processing after sufficient solvent flash-off.
Which application methods are supported?
The supplied data set lists dip, spray, brush, flow, and automated pattern coating. Process fit should be confirmed against the target wet-film thickness, board layout, masking approach, and keep-out areas.
What does the UV indicator confirm?
The UV indicator supports inspection of coating presence. It should not be treated as proof of final dry-film thickness, full cure, adhesion, absence of defects, or long-term electrical reliability.
Is Low VOC the same as solvent-free?
No. DOWSIL™ 1-2620 Low VOC is a solvent-borne silicone resin solution. Review the current SDS before storage, handling, dispensing, curing, cleaning, transport, or waste disposal.