How does PCM (Phase Change Material) produce cooling sensation for cooling bedding?

What is PCM ( Phase Change Material )

When people knows PCM for the first time, they will understand it as a cooling chemical agent, cooling finishing agent, or the cooling fabrics, but actully if we analyze its composition, the PCM ( phase change material ) we use for cooling bedding, cooling pillow, cooling textile products is the modified and formulated paraffin wax.

PCM ( Phase Change Material ) is not the common paraffin wax, but is a product achieved through chemical structural modification and carbon chain control, allowing it to maintain the temperature close to our skin temperature, this temperature ranges make people comfortable. It can stably transition from solid to liquid form, thereby absorbing heat, releasing heat and controlling heat, thus making people feel the lasting and mild cool.

Ordinary paraffin wax is just wax, but PCM is functional wax which can conduct the intelligent temperature control.

The Core Principle of PCM: Cooling Comes from Phase Change Heat Absorption

The reason why PCM ( Phase Change Material ) can have cooling ability, that is because its action of transition from a solid state to the liquid state, during the transition process, PCM absorbs a significant amount of heat.

• When the human body contacts with a PCM product ( such as a PCM cooling pillow, a PCM cooling mattress, or PCM cooling fabric), the body heat is transferred to the PCM products.

• Once the temperature reaches the PCM’s melting point, typically between 26°C and 30°C which is the range most comfortable for the human body.

• The PCM begins to slowly melt, transitioning from a solid into a liquid state.

• This transitioning process does not rise the temperature significantly, instead, the PCM continuously absorbs the heats from both the surrounding environment and the human body.

• As the heat is absorbed, the temperature of the skin’s surface drops, and the human body immediately experiences a sensation of coolness.

PCM’s working mechanism is the same as the ice melting and absorbing, however, PCM has more superior advantage, that is PCM’s melting point is precisely within the human body’s optimal comfort zone which ensures a cooling effect that is neither excessively cold nor nippy, but rather gentle and long-lasting.

Why PCM Provides Long-Lasting Cooling ( Not Just Instant Cool )?

The ordinary cooling fabrics, such as cooling silks or cooling fibers, function primarily through rapid thermal conductivity. You will feel cool the instant you lie down, but the cooling fabrics quickly warm up to your body temperature, at this moment the cooling sensation vanishes.

PCM (Phase Change Material), however, operates differently. It relies not merely on thermal conduction, but on a combination of heat storage and absorption, consequently, the cooling sensation can persist for a significantly longer period.

There are several reasons for PCM ( phase change material ) lasting cooling as under

•  During its phase-change process, the temperature of PCM remains essentially constant, maintaining steadily around its melting point.

•  It possesses a substantial capacity for storing latent heat. One gram of PCM can absorb a vast amount of heat which is far more than cooling fabrics.

•  As long as the human body continues to dissipate heat, the PCM will continue to absorb it.

•  Even as your body temperature undergoes slight fluctuations while you sleep at night, the PCM dynamically adjusts in response, consistently maintaining a comfortable temperature.

As a result, you will notice the difference:

Standard Cooling Fabrics: Provide a cooling sensation for only about 5 minutes—just the moment you lie down.

PCM Cooling Sensation: Sustain the cooling effects for several hours, ensuring a more stable and consistent temperature throughout the entire night.

Why Modified Paraffin Wax Is the Best PCM for Cooling Products?

In the market, there are various types of Phase Change Materials (PCMs), including salts, fatty acids, and polyethylene glycols available, but why do home textiles, cooling mattresses, and cooling pillows almost exclusively utilize modified paraffin-based PCMs?

There are several reasons related to the cooling performances as under

• Adjustable Melting Point : The adjustable melting range aligns perfectly with the human body’s thermal comfort zone (25–30°C), ensuring the most comfortable cooling sensation.

• Stable Phase Transition : The phase-change process is highly stable, neither super-cooling nor stratification, which ensuring that the cooling effect remains consistent rather than fluctuating in intensity.

• High Latent Heat : PCM( Phase Change Material ) Possesses high latent heat and strong heat absorption capabilities, bringing you a cooling sensation that is more obvious and long-lasting.

• Chemical Stability : PCM( Phase Change Material ) is chemically stable, non-toxic, and non-corrosive, making it completely safe for direct skin contact.

• Micro-encapsulation Compatibility : They can be successfully encapsulated into microcapsules, allowing them to be seamlessly integrated into foams, fibers, and coatings without falling or migrating.

In short, only modified paraffin-based PCMs can reliably deliver a safe, stable, and long-lasting cooling sensation in products designed for bedding, which is very close to human skin and human body.

Melting Point: The Key to Comfortable PCM Cooling

May many customer ask whether the lower the melting point, the stronger cooling you will feel.

Actually, it is not the truth. The key to the cooling comfort of a PCM lies in the design of its melting point.

• Too low melting point ( i.e < 20℃) : Too cool, easy to feel cold, uncomfortable, even affects your sleep.

• Too high melting point ( i.e > 32℃) : Not easy for phase change, slow for heat absorption, no obvious cool can be felt.

• The most comfortable sleep temperature range is 26℃～30℃.

26℃～30℃ temperature range is very close to the human body surface temperature, the moment you lie down on the PCM cooling mattress, the Phase change begins to absorb the extra heat, it will not make you feel jarringly cold, at the same time it will continuously absorbs the excessive heat for you
That is precisely why the high-quality PCM cooling products emphasize the precise control of their melting points.

Micro-encapsulation: Why It Is Essential for PCM Cooling Performance?

The cooling mattresses, pillows, and fabrics you ever saw do not contain a single solid block of wax, rather, they utilize PCM that has been micro-capsulated.

The function of these micro-capsules directly impacts the cooling performance, we can illustrate as under

• It prevents the PCM from flowing, leaking, or migrating once it melts.

• It ensures the PCM is evenly distributed, resulting in a consistent cooling sensation, avoiding uneven cool or uneven warm.

• It protects the structural integrity of the PCM, enabling it to undergo thousands of phase-change cycles without any degradation in performance.

• It facilitates the seamless integration of PCM into various materials, such as foams, fibers, coatings, and adhesive systems.

• It guarantees that the cooling effect remains stable and effective even after years of use.

In short, without micro-encapsulation, PCM would merely be capable of absorbing heat, it could not be successfully manufactured into a durable cooling product.

Ultimately, micro-encapsulation technology determines both the longevity and the stability of PCM-based cooling effects.

Conclusion

PCM ( Phase Change Material ) is a modified and formulated paraffin-wax. It absorbs excessive heat through phase change transitioning from solid state to liquid state. It brings people the comfortable sleep at long-lasting comfortable temperature range (26℃～30℃), micro-capsulation technology intensifies the PCM ( phase change material) performance: absorbs excessive heat, and also releases heat when necessary, and always sustains the comfortable sleep temperature range.