What are PBT Keycaps? How are They Made?

If you are choosing a keycap set for your mechanical keyboard, then you must have already seen the different keycap materials being used and PBT keycaps are the most premium among them.

In this article, I have discussed in detail what are PBT keycaps, how are they made, how long they last, their pros and cons, and more.

Let’s get started!

What are PBT Keycaps?

PBT Keycaps are made of Polybutylene terephthalate which is a type of thermoplastic engineering polymer. These keycaps are known for having high durability, textured finish, and heat resistance (150 °C).

Here are its features and details:

Feature	Description
Material	Polybutylene Terephthalate (PBT)
Durability	Highly durable, resistant to wear and shine
Texture	Textured, grainy feel that provides tactile feedback
Heat Resistance	High melting point, around 223 °C (433 °F)
Sound Profile	Thicker construction leads to solid, less resonant keystrokes
Aesthetics	Matte finish, maintains appearance over time
Cost	Generally more expensive than other materials like ABS
Legend Printing	Suitable for double-shot molding, dye-sublimation, laser etching and pad printing
Environmental Resistance	Resistant to solvents and doesn’t degrade under UV light
Feel	Non-slippery surface, better grip during typing

About the PBT Material

PBT is Polybutylene Terephthalate. It is a Thermoplastic Engineering Polymer and its chemical formula is (C₁₂H₁₂O₄)_n. It has a melting point of 223 °C which makes it much heat resistant.

Property/Characteristic	Detail
General Information
Common Name	Polybutylene terephthalate (PBT)
Chemical Formula	(C12H12O4)n
Physical Properties
State	Thermoplastic (semi-)crystalline polymer
Heat Resistance	Can be treated with flame retardants to make it non-combustible
Performance
Mechanical Strength	High
Impact Resistance	Better than PET (polyethylene terephthalate)
Shrinkage During Forming	Very low, maintaining precise dimensions
Safety and Stability
Flammability	Can be treated with flame retardants to make it non-combustible
Applications in Electronics
Use in Keycaps	Rigid material, Highly resistant to wear, less vulnerable to UV degradation and discoloration compared to ABS
Production
Synthesis Method	Polymerization of 1,4-butanediol and terephthalic acid
Related Polymers
Comparison to PET	Slightly lower strength and rigidity, slightly lower glass transition temperature

How are PBT Keycaps Made?

PBT keycaps are made in factories by Injection molding process from the raw material Polybutylene terephthalate. This is a difficult process as this requires high temperature to take the PBT polymer to a molten state.

Here are the steps:

Making the PBT Keycaps by Injection Molding Process:

1. First, the PBT polymer pellets are melted at around 300°C.
2. The molten Polybutylene terephthalate is poured into steel keycap-shaped molds.
3. It is cooled and the material inside the mold solidifies.
4. It is de-molded and any excess plastic material is trimmed off and the surface is polished.

Printing the Legends:

Once the keycaps are ready, the final step involves printing the legends on top of each of the keycaps.

Here are the methods used for this legend printing:

Method	Description	Durability	Color Limitations	Cost	RGB Compatibility
Pad Printing	Ink stamped directly onto keys	Moderate (wears over time)	Limited (may not adhere to PBT)	Low	No
Laser Etching	Burns top layer of plastic; grooves can be filled for color	Good (engraved legends)	Limited (can fade or lose fill)	Moderate	Limited (transparent legends for RGB)
Dye-Sublimation	Heat transfers ink into plastic	Excellent (permanent)	Requires dark legends on light keycaps	Moderate	No
Double-Shot Injection	Two molds inject different colors simultaneously	Excellent (physically part of keycap)	Widest range of colors and contrasts	High	Yes

1. Double-shot Injection

In Double-Shot Injection two different colored plastics are injected into the same keycap mold.

Here is the process:

1. The first layer is an opaque layer injected into the bottom of the mold that forms the keycap’s base.
2. Next, in another mold, a different colored plastic is used and a legend is added.
3. Next, both the molds are fused to form a single keycap.

Using this technique, the legends on the keycap come out clean and remain protected from fading away.

Learn more about what are Double-shot Keycaps here.

2. Dye-sublimation

Dye-sublimated PBT keycaps have the legends printed using a special heat printing technique:

1. The keycap surface is exposed to high heat while a special dye ribbon imprints the legend into the PBT plastic.
2. The heat causes the dye to bond with the keycap at a molecular level through gas-state diffusion.

This dye-sublimation process allows for unique and customized designs. The imprinted legends do not fade or rub off compared to traditional printing since they are fused to the keycap.

3. Laser-etching

In Laser Etching, a focused laser precisely cuts the legend shape on top of the keycap surface. In this case, the legends come out pretty crisp and clear.

4. Pad Printing

For cheaper keycaps made of PBT plastic, this uses rubber pads dipped with ink. This ink is transferred from the printing plate to the keycap surface to mark the legend.

The legends printed out of this process, are prone to fading.

How long do PBT keycaps last?

PBT Keycaps last long about 20-30 years. The PBT material used in these mechanical keyboard keycaps makes them long-lasting.

However, the quality of the keycaps also matters in determining the longevity of these keycaps.

PBT Keycaps Pros and Cons

Pros

1. PBT Keycaps have high durability and can withstand heavy gaming/typing use.
2. These keycaps come with a matte finish and on top of it the surface is textured. It enhances typing grip and feel.
3. PBT material keycaps resist shine and do not face over time, thus have high longevity.

Cons:

1. The cost of PBT Keycaps is significantly higher as compared to the other keycap materials like ABS.
2. The typing sound can be louder with keycaps made of PBT polymer if you compare it to other keycap materials.

Cleaning Process of the PBT Keycaps

Cleaning these PBT keycaps is pretty straightforward and it’s great if you do it once a month.

Here are the steps:

1. Remove the keycaps using a Keycap Puller using mild force.
2. Soak the removed PBT keycaps in soap water and keep them for 20-30 minutes. This will loosen any dust or grime attached to it and will also make scrubbing easy.
3. Next, you can use a Soft brush to gently Scrub if there is any grime on the keycaps.
4. Next, Rinse and Dry the PBT Keycaps. It’s important to get it completely dry before you put it back on the mechanical keyboard again.
5. Place the PBT keycaps back on your mechanical keyboard.

While doing this, avoid using any strong solvents like acetone, or any other chemicals as they may damage its surface, and fade its color or legend.

Compared to Other Keycap Material Offerings

Here is the comparison of PBT, ABS, and GMK:

Property	PBT	ABS	GMK (ABS)
Durability	Most durable, 20-30yr lifespan	Shines quickly, 2-3yr lifespan	Mid durability, 3yr lifespan
Texture	Matte textured	Smooth, glossy	Smooth
Sound	Loudest “thock”	Softer sound profile	Clacky, loud, ABS sound
Cost	Mid-range	Cheapest	Most expensive

ABS Keycaps:

ABS Keycaps are Made of Acrylonitrile butadiene styrene (ABS) which is a polymer. These keycaps are known for their smooth texture and their lower budget offering, making them a popular choice for choosing a budget-friendly custom keycap set. 

Basic Differences:

1. ABS Keycaps are Cheaper than PBT ones.
2. PBT keycaps are more durable and brittle than ABS.
3. PBT keycaps have textured tops while ABS have smoother keycap surfaces.
4. Click sound is lower in ABS as compared to PBT. Though PBT sounds crisper.

Read More: ABS vs PBT Keycaps

GMK Keycaps:

GMK keycaps are premium quality ABS keycaps. These are made from Doubleshot Molding technology. So, we see multicolored beautiful GMK keycap options available.

These are expensive compared to the regular ABS keycaps. To know why GMK keycaps are so expensive, check out these reasons.

Basic Differences:

1. GMK’s upper surface is smoother and PBT has a textured surface.
2. GMK keycaps have lower longevity as compared to PBT ones.

Also, read about the comparison of GMK vs PBT keycaps to dive deeper into the differences.

FAQs