How to Choose a right back sheet for solar panel?

How to choose the right backsheet for your solar panels? Sure you need the best balance between quality and price... please let me clarify each items marked below:

1) TPT, integrated composite structure back sheet. the real TPT consists of three layers: Tedlar PVF Film (DuPont made )- PET--Tedlar PVF Film (DuPont made ); this solar back sheet could be bear any environment. Remember only this structure and with both sides of Tedlar Film, that is real TPT, or any other type is fake. And TPT is the most expensive back sheet, but it almost could be applied to any weather conditions.

2)KPK, Integrated composite structure back sheet. The real KPK consists of three layers: Kynar PVDF Film (Arkema made) - PET - Kynar PVDF Film (Arkema made); This back sheet could be usede for any environment too. Remember only this structure and with both sides of Kynar Film, that is real KPK, or any other type is fake. KPK is similar quality to TPT, and price much lower than TPT, but still very expensive.

3) FPF, this is totally a coating item, the both sides with fluorine coating, perhaps PVF materials, perhaps PVDF materials, or other materials containing fluorine resin. Some supplier told you it is TPT or KPK, but actually not, this item could be used for solar panels that used for better weather places, not high requirements for weather resistance. This is cheap. Some supplier said it can work for 25 years, but i still doubt the quality, since the fluorine resin coated surface could not bear much wind and sands drop test...and in very cold winter, the shrinkage will bring the air side coating skins cracking...

4)TPE, or KPE, also integrated composite structure, those back sheet are the best balance between price and quality, the structures:

PVF film-PET-PVF film or PVDF film-PET-PVDF film. if the solar panels is not used to someplace close to sea, this back sheet could serve your solar panel for 25 years, no problems.

5)TPF or KPF, those are new designs during those two years, first, the PET coated with fluorine resin on one side, and then the other side glued with PVF film or PVDF film, so it is half coating and half integrated composite structure, those back sheet with both sides fluorine materials, it meet some demands on back sheet with both sides fluorine, but lower cost comparing with KPK and TPT. this back sheet could serve your solar panels for 25 years too. TPF and TPE similar cost, KPF and KPE similar cost.

6)PPE, it is three layers back sheet, and integrated composite item, it is created for some countries which refuse the fluorine materials, PET-PET-PEVA, but this type back sheet, i still doubt it can serve for 25 years, I believe it is about 10 years. Because the PET are not strong enough for 25 years weather resistance. 

7)FPE, one side with fluorine coated, the other side glued with PEVA, this back sheet is low cost, but you can not count on the quality for 25 years.

So if you want a higher quality solar panel, you need better quality back sheet, the best choice for normal application, KPF, TPE. KPE, TPE are the best way. For a very high quality requirements, you need KPK or TPT, Since DuPont Made PVF film, price is much higher than PVDF, 

so normally the cost comparing as below:

TPT>KPK>(KPF,TPF)> (KPE,TPE)>(FPF,FPE)>PPE

But considering of fluorine materials are also a pollution to the environment, normally for 25 years quality warranty, we strongly recommend the KPF back sheet.... and it is the best choice both for quality, cost and environment...and in another word, KPF is the best choice for your PV modules at this moment...

If whoever can develop pure PET back sheet that can work for 25 years, it would be the great creation and contribution to the solar industry, how ever more and more GLASS-GLASS modules were made, in this case,less traditional back sheet would be used...