The function and characteristics of three-proof paint

1. What is conformal paint, and what is conformal paint?

Conformal paint is a specially formulated coating used to protect circuit boards and their associated equipment from environmental aggression. Conformal paint has good high and low temperature resistance; It is cured into a transparent protective film, which has superior insulation, moisture-proof, leakage-proof, shockproof, dustproof, anti-corrosion, anti-aging, corona resistance and other properties.

Conformal paint has a wide range of applications in the electronic manufacturing industry, and there are also acrylic, polyurethane and other different components of conformal paint, conformal paint is also called PCB electronic circuit board protection oil, protective oil, electronic waterproof glue, circuit board coating oil, circuit board moisture-proof paint, conformal coating, insulation paint, anti-corrosion paint, anti-salt spray paint, dust-proof paint, protective paint, coating paint, conformal adhesive, etc. So what exactly is the conformal paint? It should be said that there is no strict definition, the word "three" takes the meaning of the ancient word "many", that is, the intention of multi-directional protection, the basic role of conformal paint in daily application is to have waterproof, moisture-proof, dustproof "three-proof" performance, in addition to cold and heat shock resistance, aging resistance, radiation resistance, salt spray resistance, ozone corrosion resistance, vibration resistance, good flexibility, strong adhesion and other properties, because of its low technical content, low price, widely used in low-end products.

2. The role of the three-proof paint

Conformal coatings are specially formulated coatings to protect circuit boards and their associated equipment from bad conditions, thereby improving and extending their lifespan and ensuring safety and reliability of use. Under real conditions, such as chemical environment (fuel, coolant, etc.), vibration, high dust, salt spray, humidity and high temperature, the circuit board may cause corrosion, softening, deformation, mildew and other problems, resulting in circuit board circuit failure. Conformal paint is applied to the surface of the circuit board, forming a flexible film with a thickness of about 50-100 microns. It protects circuits from damage under relatively harsh conditions.

3. Characteristics of conformal paint

1. One-component, low-viscosity resin, suitable for brushing, spraying, dipping, leaching and other processes, with good adhesion.

2. It has good high and low temperature resistance; After curing, it forms a transparent protective film, which has the properties of insulation, moisture-proof, leakage-proof, shockproof, dustproof, anti-corrosion, anti-salt spray, anti-mildew, anti-aging, and corona resistance.

<！--[endif]-->

1. The application of conformal paint should be carried out in a separate closed room, and the operation room must have good ventilation facilities.

2. Smoking, eating, and drinking are prohibited in the operation room, and alcoholic beverages should not be quoted before work.

3. Wear a mask or gas mask, rubber gloves, chemical protective glasses and other protective equipment during operation to avoid injury to the body.

4. After the work is completed, the used utensils should be cleaned in time, the tools and equipment should be sorted and tested, and the containers with conformal paint should be tightly covered.

5. The workplace should be clean and dust-free, free of dust, and irrelevant personnel should be prohibited from entering.

6. Tools and equipment should be fully grounded and electrostatic protection measures should be taken.

7. Do not place the circuit boards on top of each other during operation; The PCB board should be placed horizontally.

8. Before each batch of raw materials is used, a small sample curing test should be done.

(4) Places where conformal paint cannot be coated

1. High-power band heat dissipation surface or heat sink element, power resistor, power diode, cement resistor.

2. DIP switch, adjustable resistor, buzzer, battery holder, safety holder (tube), IC holder, tactile switch.

3. All types of sockets, pin headers, terminal blocks and DB heads.

4. Plug-in or stick-on light-emitting diode and digital tube.

5. Other parts and devices that cannot use insulating paint as specified in the drawings.

6. The screw holes of the circuit board and board cannot be painted with conformal paint.

(5) PCB board requirements coated with conformal paint

1. The surface of the circuit board should not have flowing paint, dripping, or semi-wetting.

2. The conformal paint layer should be flat, bright, and uniform in thickness, and protect the surface of the pad, sticker components or conductors.

3. The surface of the paint layer should not have orange peel, bubbles, pinholes, or ripples.

4. Conformal paint does not need to be applied to devices or components that do not need protection.

5. The printed board after the three-proof should be clean and tidy, and there should be no damage to components.

6. There are no defects and foreign objects such as dirt, handprints, corrugations, shrinkage holes, dust and other defects and foreign objects on the board surface and components, and there is no powdering or peeling.