PCB moisture-proof waterproof and salt spray corrosion nano materials and processes


Nano coating overview

The nano-moisture-proof coating is a colorless, transparent, non-toxic and non-flammable liquid nano-material that resists moisture, moisture, and salt spray. According to the different applications and quality requirements, it is recommended to use different concentrations of New Wood Coatings. The product is widely used in: electronic digital products, electronic components, PCBA board, precision motors, bearings, precision instruments and other fields.

 

Nano waterproof basic principle

Nano-coating A transparent thin-film coating that is about one-thousandth of the thickness of human hair. The low-convex surface of the nano coating can adsorb surrounding gas molecules and form a stable gas film, avoiding direct contact between the material and water molecules. The formation of a net-like conjunctiva on the surface of the PCB effectively reduces the surface energy of the circuit board and electronic components. At this time, the contact angle of the water droplet tends to the maximum, and the surface of the PCB exhibits a super hydrophobic property.

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The difference of water droplet contact angle between ordinary surface, super hydrophobic surface and nano coating surface

Since the pore size of the surface is much smaller than that of water molecules, the water-repellent effect similar to that of the lotus leaf is formed (the so-called lotus leaf effect is extremely hydrophobic).

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Lotus effect

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Microstructure and Superhydrophobic Effect of Lotus Leaf Surface

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When the TIS-NM nanocoating was coated on the PCBA, it exhibited excellent hydrophobicity. The drip test was performed on two identical PCBs. The contact angle of the water droplets showed a very different state, as shown in the following figure: Common PCB surface and TIS- Comparison of Droplet Contact Angles on NM Nano-Coated PCB Surface

 

Comparison of PCB surface hydrophobicity (left surface is universal surface, right surface is surface coated with TIS-NM nano coating)

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Dynamic display of superhydrophobic effect on PCB surface

 

TIS-NM nanocoating heat resistance (decomposition)

Decomposition temperature: When the temperature changes to reduce the product weight by 5% (*TGA), the film begins to decompose.

Different temperature fields cause different decomposition properties.

Below 400°C Monomer C-C bonding 347kj/mol

Below 450°C Risk of HF generation C-F bonding 440kj/mol

 

*TGA, refers to the Thermo Gravimetric Analysis method. A method of measuring the weight change of a product under the condition that the temperature is changed or maintained at a certain temperature.

 

Moisture resistance of TIS-NM nano coating (JIS-Z-0208 40°C 90%RH)

Resin type

1) A company's polyurethane resin single component

2) B company's acrylic resin one-component

3) B company's polyurethane resin one-component

4) TIS-NM R3008

 

Film thickness (μm)  

1) 30

2) 100

3) 100

4) 8

Moisture permeability (g/m2/24H)

= Conversion of water volume per square meter per 24 hours

1) 880

2) 230

3) 300

4) 640

The above data shows that the use of TIS-NM coating thickness requires only 1/3-1/4 of acrylic, polyurethane can achieve the same degree of moisture permeability.

The thickness of the coating around 8 μm is also superior to the moisture permeability of the ordinary polyurethane resin one-component coating.

The product is characterized by the use of a very thin coating thickness to achieve moisture resistance. The thin coating thickness can also achieve good heat dissipation performance and heat dissipation performance is better than similar products.