Polyamide Backsheets From Tomark-Worthens Join the Fray for Backsheets Market

By Saur News Bureau/ Updated On Tue, May 26th, 2020

Backsheets, literally the backbone of your solar modules, have been on their own trail of innovation and improvements, ever since the cell and modules part of the business picked up pace. Importantly, with the relentless pressure on the solar sector to match costs of competitors like thermal and others, every part of the supply chain has to get better, without really increasing costs. Joining the fray is a new invention, polyamide based backsheets.

Now comes the news that US backsheet manufacturer Tomark-Worthen LLC has developed a polyamide-based solar backsheet. This has been done using continuous co-extrusion processing. Co-extrusion is distinct from lamination in that multiple plastics are fused together without the use of adhesives. The result can create materials with properties quite distinct from its constituent materials. Tomark-Worthen adds that the product is cost-efficient and weather-resistant, attributes considered critical for any market success today.

Tomark-Worthens’s PhotoMark Reflections 205-3 backsheet, as it has been called, benefited from the the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the SunShot initiative. The focus of this initiative is to develop and support domestic manufacturing in the US.

For readers who may be unfamiliar, a PV module backsheet is a multi-layered polymer or even a second glass sheet in case of bifacials, that interfaces to the encapsulant on the cell side and the air on the other.

For a long time from the 1990s onwards, solar modules used polyvinyl fluoride (PVF) as the outer layer of the backsheet, and often as the inner layer also. PVF backsheets have been proven winners, delivering a very reliable experience for developers. The 25 year guarantee we see on most solar modules today owes a lot to the actual experience with PVF based backsheets.

With intense competition, many other options like polyethylene tetraphthalate (PET) as the core layer, PVF, polyvinylidene fluoride (PVDF), hydrolysis-resistant PET, polyamide (PA), fluorine coating, fluoro resin or fluoroethylene vinyl ether (FEVE) have been developed. The focus being on higher manufacturing efficiency and lower costs, like the rest of the solar value chain.

Tomark-Worthen claims that its polyamide version will be available white and white/black versions and weighs in at 236 g/m², with a thickness of 205 micrometers. It is manufactured without poly-ethylene-terephthalate (PET) or fluoropolymers, and no interlayer adhesive.

LIke many other innovations in the segment, US chemicals giant Dupont has a role here too, with the backsheet based on a new polyamide-ionomer alloy developed by it. Duponts’ Tedlar backsheets have for long dominated the market with their Poly Vinyl Fluoride based films.

The new launch is squarely aimed at the existing AAA and polyvinylidene fluoride (PVDF)-based backsheets segment, where the firm claims that its new backsheets outperforms competition comfortably.