A laptop keyboard may be pressed tens of thousands of times every day. Sweat residue from fingers, accidental water droplets, and long-term exposure to moisture can gradually corrode the silver conductive circuits on the membrane circuit board, eventually causing key failure.
Hidden inside the keyboard membrane circuit is an “invisible guardian” — Waterproof Adhesive.
What Is Waterproof Adhesive?
Waterproof adhesive is a two-component pressure-sensitive adhesive specifically designed for screen printing applications.
In simple terms, it is printed onto the membrane circuit board of a keyboard and, after curing, forms a dense protective layer. This protective film serves several important functions:
Water Resistance: Forms a barrier on the circuit surface to prevent liquids from penetrating and damaging silver circuits.
Corrosion Protection: Shields circuits from sweat, moisture, and other corrosive substances.
Enhanced Adhesion: Improves the bonding strength between the conductive circuit and substrate.
Flexibility and Durability: Allows the circuit to withstand continuous bending and repeated keystrokes without cracking.
Without this protective layer, a keyboard could experience circuit failures within just a few months of use.
Betely's Three Waterproof Adhesive Series
Betely offers a comprehensive waterproof adhesive product line designed to meet mainstream application requirements.
| Product Model | Mixing Ratio | Viscosity (mPa·s) | Curing Condition | Application Scenarios |
| SF-6102A/B | 100:2 | 5000-6000 | 125-150℃ / 60-120s | General grade, suitable for most keyboard circuits |
| SF-6110A/B | 100:1.5 | 6000-8000 | 125-140℃ / 60-90s | High-viscosity grade, ideal for high-precision printing |
The three product series share the same core performance specifications:
| Performance Index | Test Method | Parameters |
| Solid Content | GB/T 2793-1995 | 48-52% |
| Peel Strength (on PET) | ASTM D3330 | ≥500 gf/inch |
| Waterproof Duration | 60℃, 10 cm water depth | ≥ 3 hours |
| Printability | 100-200 mesh screen | Smooth printing, no screen clogging |
This means that regardless of the model selected, users can obtain stable and reliable waterproof protection.
Technical Performance Behind the Numbers
1) Peel Strength ≥ 500 gf/inch
Peel strength is one of the key indicators used to evaluate adhesive bonding performance. The higher the value, the stronger the bond between the adhesive layer and the substrate.
A peel strength of ≥500 gf/inch means:
The adhesive layer remains firmly bonded to PET or PC substrates.
The membrane circuit maintains structural integrity even after repeated flexing and bending.
Long-term durability is ensured under normal operating conditions.
2) Waterproof Performance ≥ 3 Hours (60°C, 10 cm Water Depth)
This test condition is significantly more demanding than typical daily usage.
Withstanding immersion in 60°C warm water at a depth of 10 cm for more than 3 hours demonstrates that the adhesive provides ample protection against everyday exposure to sweat, water droplets, and moisture at room temperature.
3) Excellent Printability
Waterproof adhesive is applied through a screen-printing process.
Using 100–200 mesh screens allows manufacturers to achieve:
Sufficient coating thickness (16–20 μm)
Precise circuit pattern printing
Consistent production quality
Betely waterproof adhesives offer excellent printing performance and are fully compatible with 100–200 mesh screen printing processes, ensuring smooth and efficient production.
Application Areas
Betely waterproof adhesives are widely used in membrane switches, keyboard circuits, and various electronic applications.
Typical applications include:
Laptop keyboards: Protect silver conductive traces from sweat and water exposure.
Membrane switches: Used in home appliances, industrial control panels, and equipment interfaces.
Flexible printed circuits: Suitable for electronic circuits requiring waterproof protection.
From consumer electronics to industrial equipment, Betely waterproof adhesives provide reliable protection wherever membrane circuits require moisture resistance.
Why Choose Betely Waterproof Adhesive?
1) Proven Reliability
With more than 20 years of experience in electronic coating materials for the 3C electronics industry, Betely has continuously optimized its waterproof adhesive products.
The products have been successfully adopted on multiple customer production lines and deliver consistent, stable performance.
2) Outstanding Printing Performance
Superior printability leads to higher production yields and lower cleaning and maintenance costs.
3) Fast Curing
Curing conditions:
125–150°C for 60–120 seconds
The product is compatible with existing IR curing lines, eliminating the need for additional equipment investment.
4) Environmentally Compliant
Betely waterproof adhesives comply with environmental regulations such as RoHS, making them suitable for global export markets and environmentally responsible manufacturing.
Conclusion
Waterproof adhesive is small—so small that most people never notice it.
Yet on every protected keyboard membrane circuit, it quietly safeguards every keystroke.
Today, Betely Waterproof Adhesive is widely used in the membrane circuits of mainstream laptop keyboards, helping ensure long-term reliability and durability.
What You Should Know About Waterproof Adhesive
✅ What It Can Do
Creates a protective layer on keyboard membrane circuits that helps prevent sweat, moisture, and everyday liquid exposure from damaging silver conductive traces.
❌ What It Cannot Do
It cannot prevent damage if an entire cup of water is spilled into a laptop.
If a large amount of liquid enters a keyboard, immediately:
1. Power off the device.
2. Disconnect the power source.
3. Seek professional inspection and repair.
Waterproof adhesive protects the circuit layer—but it is not a substitute for comprehensive waterproofing of the entire device.
