Parylene coatings have been widely applied in the area of electronic devices. Currently there are four types of parylenes used in industry and they are Parylene N, C, F and AF4.
Parylene AF4 (named as Parylene-AF4 by SCS and Parylene-SF4 by Kisco) is very expensive because the production cost is very high. It is estimated that the current price is around 10000$/kg. Among Parylene N, C, F and AF4, Parylene AF4 coating actually performs the best in heat resistant and UV-resistant tests. Parylene AF4 mostly is utilized in the production of military weaponry and is rarely used in civilian market. The development of Parylene AF4 market is hindered by the following problems:
1. It is difficult to acquire Parylene AF4 in large quantity because of its production problems. So far no company has been able to supply it on a scale more than 100kg.
2. Because of its application in military weapons, the US market has so far refused to sell it to the Chinese market.
3. Low efficiency in the coating process. Since the reactivity of the Parylene AF4 monomer after thermolysis is too high, the coating forming efficiency is actually lower than the other three types.
4. Requiring the use of special coating instrument. The coating of Parylene AF4 needs to be carried out at low temperature and the common parylene coating instruments need to be upgraded.
Since the performance of Parylene N and C cannot fully satisfy the market demand when they are used as heat resistant and UV-resistant materials and Parylene AF4 is too expensive, it would be highly desirable to develop a type of parylene which can perform much like Parylene AF4, yet considerably cheaper. Taking all these into consideration, Shanghai Qixing New Material Co. has started collaboration with Professor Ze Tan at Hunan University for the last several years and has successfully developed the production process for “Parylene AF4-substitute”, i.e., Parylene F (Parylene–Vt4). Currently our company has completed the manufacturing process development and the production capacity is around 300kg per month. The purity of our Parylene F product is greater than 99% and our price is the lowest among all the suppliers.
The following are some of the characteristics of Parylene F (Parylene–Vt4):
Figure 1
From Figure 1, we can see that the highest temperature Parylene N and C can endure for long period is 60 oC and 80 oC, respectively. On the other hand, the highest temperature that Parylene F can endure can go as high as 200 oC. So Parylene F can be used in places where Parylene N and C can not meet the heat resistant requirement. Currently many companies are making use of this heat resistant advantage of Parylene F and are applying it in the production of auto parts, motor switches as well as wearable devices.
UV-resistant performance of Parylene F
Parylene F is widely used in the production of high end LEDs because of its excellent UV-resistant performance. In contrast, Parylene N and C coating can start to turn yellow after being exposed to the sun for 2 weeks. Next cracking of the Parylene N and C coating will appear and the protection of material underneath the coating will be lost. This is due to fact that Parylene N and C coatings will be fragmented and turned into benzoic acid and benzaldehyde derivatives when they are exposed to high temperature or light. The transformations are shown below.
Figure 2
In other areas such as water proof ability and low dielectric constant, Parylene F (Parylene–Vt4) can perform as well as Parylene N and C. The following figures are some of the characteristics of Parylene F vs Parylene N and C.
Figure 3
Figure 4
Figure 5
Figure 6
From Figure 3-6, we can see that the performances of Parylene F can match those of Parylene N and C in terms of water proof ability and dielectric properties. In addition, the friction coefficient of Parylene F is as small as Parylene N. It is also a biostable, biocompatible coating and FDA has approved it use for various applications.
In summary, Parylene F (Parylene–Vt4) holds clear advantage over Parylene N and C as a heat resistant and UV-resistant coating, yet it also shares all the other good properties of Parylene N and C. It is an excellent substitute of Parylene AF4, only much cheaper. If you need Parylene F, you call Manger Guo of our company at 15116235351. Our company can also help you with the actual coating process.
