The Continued Evolution of Solvent Photopolymer Plate Processing
APR prides itself in not just quoting equipment and providing solution based consumables, but making it a point to thoroughly understand a customer’s needs and goals. As water wash plate technologies continue to evolve into a viable competitor to solvent and thermal processing through improved print quality and longevity; chemists developing polymer and solvent chemistry are not sitting back and resting on their past success. Optimal plate and print quality has never been the problem with a solvent system. Where solvent has been challenged in the past has been dry time, odor, and sustainability. That has now changed as the solvent processing environment has continued to evolve in recent years, both in terms of chemistry and equipment. Here are some compelling statements about solvent photopolymer plate processing that you might not know:
- Environmentally friendly
- Quick plate throughput competitive with water and thermal
- Proven history and unsurpassed quality
- Widest variety of polymer materials available
Processors & Solvent Washout Solution
- Solvent wash systems have been in place the longest in the industry, provide unsurpassed plate quality, and an extremely user-friendly platemaking process with lower upkeep and maintenance compared to water wash systems.
- New processor technologies have increased not only throughput and consistency for platemakers, the newest systems have significantly improved in the area of VOC containment as well.
- Note: VOC’s are not limited only to solvent processing.
- Each state has "de minimis" rulings. De minimis is a legal term for an amount that is small enough to be ignored, i.e. too small to be taken seriously. Many commercial solvent wash systems are considered de minimis based on calculated and measured emissions.
Example: [Ohio], if a unit emits less than 10 pounds per day of any criteria pollutant, the unit is considered “de minimis”. This is equivalent to nearly 15 million sq. inches per year of solvent processed .067" photopolymer.
New Solvent Chemistry
- New solvent chemistry has provided lower odor, lower HAPs, and lower VOC alternatives to the technologies of the past.
- HPS has now released a brand new chemistry that TSG would classify as “NO ODOR”
- Some more recently developed washout chemistry has actually received the EPA’s Presidential Green Chemistry Award.
- Because of the minimal plate swell in the washout process, some solvent chemistries have the ability to dry in as little as 35 minutes.
- New solvents operating at room temperature can significantly reduce the amount of solvent lost through evaporation during the washout process.
- New non-‐hazardous washout chemistries are available and viable options.
- Worker conditions and safety are greatly improved with these solutions due to high flashpoints, low vapor pressure, and minimal to no odor.
- New solutions NOT requiring heat during plate processing, reduces chemistry evaporation by up to 7%, further reducing VOC admittance.
- New chemistry can reduce plate swell by as much as 65%, resulting in a significant reduction in dry time (typical bottleneck). It is no longer uncommon for plates to be completely dry and return to their original thickness in as little as 25 minutes.
- Reduced dry times can mean throughput is “as fast” as other plate technologies including water and thermal.
- Some of these solvent chemistries are made up of single component or even dual-component chemistries (with common distillation temperature/rate) DO NOT go out of balance or require surrogate solutions post distillation when set to the manufacturers recommended/optimized distillation settings.
The solvent process environment provides flexibility in multiple areas, including the ability to interchange polymer products with high confidence in plate quality; i.e. multiple plate types, supplier options, and plate thicknesses.
Multiple options exist for waste solvent handling: either internal distillation or via external options.
- Modern solvent recovery systems (recyclers/distillation units) can recover in excess of 98% of solvent washout chemistry introduced to the system.
- These systems can be extremely and completely safe. Units certified explosion-proof and are also certified to UL2208 for use in non-hazardous locations. Explosion-proof electrical equipment (class 1, division 1, equipment). In short, some units are classified where they could be placed in an office environment.
- Redundant high-temperature controls that shut down the equipment at a predetermined safe maximum limit. This applies both to the heat transfer oil and solvent recycling.
When many think of the environmental impact of solvent wash plates they are not considering that the actual washout solution and polymer waste can be non-‐hazardous. Historically solvent was not a technology viewed as the fastest method in which a plate can go through the entire process post-CDI; now it can be just as fast as alternative plate making technologies and still offer what is arguably the highest quality plate on the market.
If you want to learn more about this subject, please feel free to reach out to us by calling 1-800-445-4017, or by e-mail at [email protected].
All Printing Resources has formed our Technical Solutions Group (TSG) to encompass our full range of expertise in all critical areas of the flexo process. This team is made up of industry professionals dedicated to being up-to-date on new technologies along with best practices. They are armed with the latest in diagnostic tools and are experienced in problem-solving that can achieve sustainable results. The TSG has walked in your shoes, and have felt your pain.