Impressions - February 2020 - 19

Shown is a design printed
using AXEON non-PVC
acrysol inks, mainly the
fluorescent variety. Artwork
reprinted with permission
from David Edward Byrd.

feel as well or better than traditional plastisol.
Water-Based and High-Solids Water-Based: Many tout
water-based ink as the most eco-friendly or sustainable choice available. However, it's worth examining the contents more closely.
This ink type not only contains water, but also many binders, pigments and, often, solvents or volatile organic compounds (VOCs) to
help it dry quicker or stay open and usable in the screen. As the ink is
cured in the dryer, the VOCs are released into the air. A quick glance
at safety data sheets may reveal Propylene Glycol (PG), which can
be used as antifreeze, or Diethylene Glycol (DEG), another VOC
that has been classified as poisonous if swallowed, according to the
U.S. National Library of Medicine.
Due to the ink's water content, mold can grow in the container,
rendering it unusable within a year or so. Many manufacturers include additives to inhibit mold growth, while others may aid in better
curing or printing. These chemicals may or may not be released into
the air during the curing process.
Once plastisol or acrysol ink has been deposited in the screen but
not consumed, it can be returned to its original container. Since these
inks contain little to no VOCs, they still are the same as when the
container was first opened.
A typical water-based ink would change viscosity during the
screen-printing process, as some evaporation occurs. It may be possible to simply add some water to make it a usable product, but it
typically requires an additive. Often, the ink is too dry to be properly
reconstituted for printing and must be disposed.

Burning and Developing Screens

Ink Disposal

Ink Choices

Printing Parameters

This process uses more precious water and chemicals, so it's important to get it right the first time. Check your exposure times with a
calculator weekly or at least once a month. Store your screens in a
light-safe environment. Light is like lead poisoning for screens; it will
slowly expose screens and fine halftone dots will start to disappear.
Today, the most common film is the inkjet type; it's convenient but
there is some plastic film that can be recycled, but seldom is. With
the computer-to-screen (CTS) trend, a plastic film backing no longer exists, which certainly reduces plastic use. However, if a screen
needs to be burned again, then doubled ink costs must be considered.
The newest trend, the CTS laser, uses no consumables and achieves
extremely high resolutions. It comes with a high initial cost, but is
much more environmentally friendly in the long term. It's better to
burn the screen correctly the first time; however, if you have to burn
it again, there are no consumables washed down the sink during
development.

How sustainable are your ink choices? The following are pros and
cons of each main ink type available in today's marketplace.
Plastisol: The most common screen-printing ink, today's plastisols don't contain the restricted phthalates that were banned several
years ago, nor do they include hazardous lead or other dangerous
chemicals that were prevalent about 40 years ago.
Most screen printers have used plastisol ink and are accustomed to
its characteristics and curing parameters. This ink type contains 100%
solids, meaning there is no gassing off and minimal loss when it is
printed and cured. It contains minimal to trace amounts of solvents;
doesn't dry in the screen; and is very opaque and easy to manage
Acrysol: This is a newer, PVC- and phthalate-free ink type. Most
work like plastisol, but some fall short of being a substitute because
of the newness factor. During the past couple of years, much has
improved with regard to printability and hand. Some even print and

Regardless of whether you're using plastisol or water-based inks,
both contain chemicals whose disposal is strictly regulated. In all
cases, familiarize yourself with local, state and federal rules regarding this process.
Plastisol inks are 100% solids. When fully cured, the PVC resin
fully absorbs the ink's plasticizers to form a plastic ink film or solid.
Some municipalities may allow fully cured plastisol inks to be disposed or recycled as regular plastic waste. Uncured plastisol may be
eligible for recycling. If not, it likely must be processed by an authorized chemical-waste disposer.
Despite its name, never pour water-based ink down a sink or into
the ground, and never throw it in the garbage. Some of its components are considered hazardous. Local laws may allow you to reduce
disposal volumes by opening the lids and allowing the water and any
solvents to evaporate. The remaining pigmented binder should then
be disposed in accordance with local regulations.

The importance of using the correct emulsion mainly applies when
using water-based ink, as plastisol and acrysol inks use the standard
emulsion types. Water-based inks require a specific emulsion that is

Pallet Adhesive
A water-based pallet adhesive is more efficient than a spray adhesive. Although
the latter may be convenient, much of the
adhesive and its chemicals get dispersed
in the air during application.

FEBRUARY 2020

P.19

Impressions - February 2020

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