Reclaiming Issues?

My Screens Won’t Reclaim Easily, Why?

First what do you clean your screens with? What does your screen cleaner have to do with screen reclaiming you may wonder? Well emulsions when underexposed are still sensitive to both light and solvent based chemistry which can lock in the emulsion and

make reclaiming difficult. In recent years there has been a trend away from mineral spirits, recirculating partscleaners and paint thinner as a wash up chemical for plastisol inks. Driven by local air quality control agencies trying to limit Volatile Organic Compounds many solvent chemistries have been banned in favor of low VOC screen cleaning chemistry. Yet there are still many areas of the world and shops that use solvent chemistries as well as 'hotter' chemistries like MEK, Xylene, Acetone and Screen Openers for faster cleanup of

plastisol ink. These chemistries can have an adverse affect on the emulsion and the reclaiming process which we will discuss in a moment.

The advantage of the newer cleaning products is theyhave less harmful affects on the worker and the environment. In additionThe advantage of the newer cleaning products is they have less harmful effects on the worker and the environment. In addition to worker safety the new chemistries do not affect emulsion like the solvent chemistries mentioned above. To understand how emulsion can be affected by screen cleaning chemistry and become diffcult to reclaim we need to look at the many different types of emulsions. 

There is a reason for the variety of emulsions in our catalog due to the wide variety of inks that can be printed. The different emulsions can be viewed as a spectrum. You can have emulsions designed to withstand water base and discharge on one end, and emulsions that can withstand hot solvent inks on the other end of the spectrum. There can also be emulsions that fall in between and can withstand both solvents and water but rarely have the durability to withstand them as well as one specically formulated to withstand either water or solvents. 

Underexposed screens can still be sensitive and have un-cross linked sensitizer. While these chemistries can quickly clean or open up the image the emulsion can get 'locked' in and be dicult to reclaim down line in the production process. To x this issue we need to go back to how the screen was exposed, and did it receive any post exposure to complete the cross linking of all sensitizer?