Aqueous and UV Coatings Tricks to Cleanup Process

Aqueous and UV / EB Coatings have distinct cleanup methods that can make the processes run better.  This article will address specific tricks to cleanup before, during, and after press runs of aqueous, UV, and EB Coatings.

Safety First and Second

We will tackle the important steps in the cleanup of coatings for both Aqueous Coatings and UV /EB Coatings.  This will be stated over and again: Start by reading the Safety Data Sheets (SDS) of the products you are handling.  The use of Personal Protective Equipment (PPE), such as safety glasses, gloves, and other precautions should not be ignored. Since these coatings have separate and different properties, each coatings group will be addressed separately.

Steps for the Cleanup of Aqueous and Waterbased Coatings

First, read and refer to a specific coatings Safety Data Sheet (SDS) for all essential safety and handling information. In regard to cleaning-up we recommend the following:
Whenever aqueous coatings are being handled, wear safety glasses and rubber protective gloves. Open containers of aqueous coatings and use coatings in a well-ventilated space. After handling aqueous coatings wash up thoroughly with soap and water, and rinse.
Aqueous coatings, often being 30-40% solids are formulated to dry to the touch, quickly as the water component is evaporated leaving the solids to form a film. Importantly, most aqueous coatings will rewet, so that moving coater parts seeing fresh coating will not dry or tack up.

AQUEOUS COATINGS CLEANUP BEFORE A PRESS RUN

1. Wipe down coater rollers, blanket, or plate, etc., with water removing dust.
2. Wipe out the coating pan similarly.
3. Purge any water from hoses before pumping the coating.

AQUEOUS COATINGS CLEANUP DURING A PRESS RUN

1.  After any short press stoppage (under one minute) start up again normally.
2. If stopping for longer than one minute, wash the coater blanket, and/or plate with water and dry. Some presses now have auto blanket wash-up devices.
3. If any ink appears on the coater blanket, remove it with an appropriate press wash, and then wash with water and dry.
4. If any coating appears on a backup (impression cylinder) and develops tackiness, it may be cleaned with warm water.

AQUEOUS COATINGS CLEANUP AFTER A PRESS RUN

1. Wash the blanket with warm water being sure that the warm water is not setting- up the coating. If it is, use cold water throughout the clean-up process.
2. Clean any coating from the impression cylinder with warm water, or the more aggressive cleaners mentioned below.
3. Drain the coating pan, pumping the coating back into the supply container.
4. Flush and rinse the pan and hoses, cleaning coater rollers with warm water running at least 5 gallons through the system. It is recommended to clean a system thoroughly monthly.

With clean-up that is difficult try a warm water/10% ammonia blend. If dry, semi-dry spatters, and drips are evident, a 50% water/50% ammonia mix that is let to set for 5 min. will clean effectively.

If a coater will be idled for a while, pull the coating blanket and packing, and coat the blanket cylinder with an anti-corrosive agent like oil or kerosene. When anilox or gravure cylinders are used, clean them with very warm water and use the manufacturer’s recommended cleaning agent, and brush cells cleaning thoroughly following specs. Also if you are using a coating circulation system such as from Harris & Bruno, MMT, or Tresu, follow the instructions for preparing, running, and cleaning up after coating.

INSTRUCTIONS FOR SPILLS & DISPOSAL OF AQUEOUS COATINGS

Since aqueous coatings vary in components, it is important to follow the instructions on the SDS sheets.  Always contain spills diluting 50-fold or more for sewer disposal, or absorb in an inert material for waste disposal per federal, state, and local regulations.

Always use appropriate Personal Protective Equipment (PPE) when handling coatings.

Tips for the Cleanup of UV and EB Coatings

Always read and refer to a specific coatings Safety Data Sheet (SDS) for all essential Safety and Handling information. With regard to cleaning up we recommend the following: Cork’s CORK-CLEAN™ blanket, roller wash, and system flusher is your answer for fast, effective, and safe clean-up. It is a proven success as an equipment, blanket, roller, and anilox wash for all commercial UV/EB inks and coatings.

UV coatings contain reactive components which are often irritants, and sometimes have allergic reaction causing sensitizers. Safety glasses and skin protection with neoprene gloves are a must. Open containers and use coatings in a well-ventilated workspace. Wash hands with soap and water, never solvents, after exposure to coatings, and routinely before breaks and after work. Do not launder coating contaminated clothing at home, potentially exposing others.
Clean-up is not necessary when coating continuously, since UV/EB coatings stay open and don’t dry even during downtimes. This is provided UV coatings are shielded from cure-initiating UV light, sunlight, or lighting exposure.

UV Coating Tips Before a Press Run

1. Wipe down the coater pan, rollers, blanket, and/or plate to remove any dust using a detergent/water mix with an IPA rinse. Don’t use hydrocarbon solvents as they can turn a UV/EB coating gummy. Fast-drying MEK, MIBK Toluol, or CORK-CLEAN™ may also be used.
2. Purge any excessive clean-up solvents from the plumbing before pumping coating.

UV Coating Tips During a Press Run

1. During press stoppages, clean-up is generally not necessary.
2. If conventional, or UV/EB ink appear on a coater blanket, remove it with a press wash, like CORK-CLEAN™, and dry.

UV Coating Tips After a Press Run

It is also not necessary to clean up after a run, especially if there is going to be a start-up again reasonably soon, using the same coating. This is provided there is no exposure to UV or other light sources which may cause the coating to cure on the coater and press parts. Cleaning-up is advised when a change is being made to a different coating, as one with/without optical brightener, or with/without a migratory lubricant.

1. Drain coating into the supply container.
2. Clean up flushing and rinsing pan and hoses using a water/detergent mix, rinsing with IPA, MEK, MIBK or Toluol, drain and dry.

INSTRUCTIONS FOR SPILLS & DISPOSAL OF UV / EB COATINGS

It is always important to follow SDS instructions. Contain spills as quickly as possible absorbing on an inert material, e.g., vermiculite, followed by shoveling up for disposal following all federal, state, and local health, pollution, and waste regulations. Cured, solid UV/EB liquids are solid waste. Uncured, they may be hazardous waste. To be safe, you can incinerate it.

Contact Cork Technical experts if you require an Aqueous or UV/EB coating with enhanced performance properties for a demanding application.
Corks’ business is the development and formulation of Aqueous, Ultraviolet (UV), Electron Beam (EB) coatings and adhesives.  To learn more contact Cork’s coating experts.