PTC stands for Positive Temperature Co-efficient, an inherent characteristic of a selected material. It means that the electric resistance of the said material increases with the increase of the temperature as shown in Figure 1.
PTC films refers to such films with the desirable PTC characteristic and inks used to form these such films, are referred to as PTC Inks.
PTC films are generally used as heating elements which mainly provide infra-red radiation to the environment which are known as PTC heating films.
Distinguished from other regular heating elements whose electric resistances are relatively constant, a PTC heating film is capable of controlling the temperature itself, by regulating its heating power via its electric resistance response to temperature.
You are welcome to click the link below for a quick review what PTC inks we have developed for your different applications:
1M PTC profile and aspect short introduction 2024
The science behind this self-regulation is based on the principal of the Ohm Law: [I = V/R, and P=I*V =V*V/R, where I is current, V is Voltage, R is Resistance, P is power).
At low temperatures, its resistance is lower, so its heating power is larger resulting in the temperature quickly increasing. While the temperature increases, its resistance rises as well and therefore decreasing its heating power at the same time.
During a short period and certain temperature, its heating power decreases to point where it simply balances the energy loss of the system, maintaining a constant.
In our proprietary PTC film, the PTC characteristics are scientifically achieved by controlling the distance between conducting domains (particles of carbon black mostly) through the designed thermal expansion of the polymeric binder employed in our PTC inks in nano-scale and in quantum fashion.
At a lower temperature (below Tg), the polymer chains are mainly frozen. Their thermal expansion is limited, so the carbon particles are closer to each other which offers high conductivity (low resistivity).
When the temperature increases, polymer chains start to move and stretch and when the temperature approaches its Tg, its expansion increases dramatically, so does the distance between carbon particles, thus as a result, the conductivity quickly decreases (resistivity quickly increases), so does its heating power.
The heating PTC film can be simply treated as an intelligent heating element, and its initial resistivity (R0) is expressed in ohm per square (Ω/◊).
Depending on the application, the effective electric resistance (W) of the final heating element can be achieved via outlaying these squares in a designed pattern.
As demonstrated in the figure, the overall heating power is function of N*V2/R0, so it can be easily manipulated by selecting any parameter of applied voltage, the overall number (N) of square in parallel, and the initial resistivity (R0).
Under optimization, the resistivity of our proprietary PTC film is designed to be around 10K (Ω/◊). In this case, each square regardless of its dimension can be viewed as a resistor of 10K, so the overall heating power can be expressed as P = N*V2/10000.
If a voltage of 110V is applied, then the overall heating power is simply expressed as P110 = 1.21N. That is to say, in a given area of any designed dimension, this PTC film would yield an initial heating power P110 = 1210 Watt if 1000 (N=1000) equivalent squares are patterned in parallel.
Of course, this heating power will automatically adjusted in response to temperature, the lower temperature, the higher the heating power. In theory, any heating power for a given area can be designed
From its inherent property, the smart heating film responds to temperatures automatically in a positive way. When the temperature is cooler, more heating power is used. When the temperature is warmer, less heating power is used.
No potential risk of hot spots. Heating power is reduced in warmer areas to maintain a constant temperature. For example: if a certain area was covered, heat diffusion would be limited; the film under this covered area would automatically reduce its heating power.
No potential risk of temperature sensing and controlling due to no external control unit necessary.
Due to PTC effect, it heats up rapidly when it is cold, which provides an instant heat (less than a minute) for warming up a cold environment such as a car in winter, an occasionally used cottage, a shower room, a sauna cabinet, etc.
Our proprietary PTC film is carbon based, and works like a black radiation; it converts electricity to heat 100% (no visible light emitting).
No external controlling unit, no extra power consumption.
More importantly, it controls temperature inherently. Not like the external control unit, where the temperature needs to be sensed first and then fed back to the control unit where it will then switch the electricity on or off waiting for the temperature to oscillate around the set temperature.
PTC heating film responds to temperature inherently and adjusts its heating automatically. This results in maintaining a balanced use of energy without over consumption.
The PTC film can be formed in virtually any substrates, from hard substrates like glass and ceramic to soft substrates like plastic film and fabrics.
As our proprietary PTC film is carbon based, it releases heating mainly in infra-red radiation, scientifically friendly to the human body.
It is an area heating source, not a hot spot, so it spreads warmth evenly and uniformly throughout the space around the human body comfortably.
Furthermore, the PTC film can be tailored to any size and any shape. So it can be applied to different locations, including automobiles, garments, building, vessel, storage tank, piping, reactor, etc..