Water-based inks are defined as those that utilize water as the main solvent. That does not mean, however that water is the only solvent. It is significant to note that many water base inks contain &#;co-solvents&#; which may even be petroleum based solvents. The reason these co-solvents are used varies, but one of the key reasons is to decrease the time and heat necessary to cure the ink film on the fabric.
Water-based ink is the ink of choice for the printing of yard goods; either in piece form or on the roll.
Water-based inks are a good choice when a &#;soft hand&#; is desirable. A soft hand is the condition where the ink film cannot easily be felt with the hand when passed across the surface of the fabric. This affect is often used as an argument for why water-based is preferable to plastisol as plastisol has more of a hand than water-based.
Water-based ink also has the advantage of being an excellent ink system for high speed roll-to-roll yardage printing. Such printing is done on large sophisticated equipment that has very large drying (curing) capacity.
Water-based ink also is a good choice where ink penetration is desirable, such as in towel printing. Towels have a high nap fabric that must be printed in a manner where the ink penetrates or wicks through to the base fabric for adequate coverage. Water-based inks that are designed to wick into the fabric are excellent for this application. Ink wicking is not a desirable affect in most other fabric printing as it will destroy the design and registration of multiple colors.
Water-based ink is much more difficult to cure than plastisol. A shop that is interested in printing water-based ink must have the drying capacity to remove the water. The dryers used for water-based printing tend to be larger than those needed for plastisol. In plastisol printing, the ink film must only reach the cure temperature for a brief moment. With water-based ink, the temperature must be reached and then held until all of the solvent (water) is removed.
There are water-based ink that will air dry but they are usually only acceptable for craft level printing as the room required for curing greatly reduces productivity. Many water-based inks can also be more quickly cured with the addition of a catalyst that will assist the heat in the curing of the ink by continuing the cure even if all of the water is not removed in the dryer.
The disadvantage of a catalyst is that once it is added to a water-based ink, it creates a time limit or &#;pot life&#; where the ink must be all used in a certain time or be discarded. Most catalyzed water-based ink pot life&#;s are between four and twelve hours.
Since water-based inks contain water as an evaporative solvent, care must be taken to prevent the ink from drying in the screen. If water-based ink is left in open mesh for even a short period of time, it can clog the mesh and ruin the screen. Practiced water-based ink printers must always be conscious of how long a screen sits between prints to prevent the ink from &#;drying in&#;. While modern water-based inks are less prone to this phenomenon, it is still a concern.
In addition, when a water-based print job will take more than one day, the ink must be removed and the screen cleaned with to prevent drying. The ink is then put back in the screen on the next work day and the job is continued.
Water-based ink is also much more aggressive than plastisol towards the emulsion that is used to create the screen stencil. Emulsion manufacturers all make &#;water-resistant&#; emulsions that must be used for water-based printing. If standard emulsion is used, the water-based ink will destroy the stencil by melting the emulsion is as little as a few minutes. Even when the proper emulsion is used, screen life tends to be much less with water-based printing than it is for plastisol printing.
There is a common misconception that because water can be used for cleaning screens, squeegees and tools, that the waste water can just be discharged in the sewer. However, the water-based ink is not just water. There are pigments, binders, thickeners, and sometimes, even co-solvents in the ink residue. Screen cleaning systems that can at least capture the solids are still recommended.
In addition, water-based that has not been catalyzed can be returned to its container for reuse. If the ink has been catalyzed, it should be considered hazardous waste unless it can be dried out (all water and solvent removed) before discarding. If it cannot be dried, it should be disposed of as hazardous waste.
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t screen-printing shop Night Owls, the crew only uses water-based inks. &#;We chose to move to an &#;ink solution&#; that offers a higher-quality print for us,&#; says Eric Solomon, owner of the Houston-based shop.
&#;We love the way water-based ink works, we love the way it elevates our printing quality and the way it&#;s helped us elevate our craft.&#;
&#; Eric Solomon, owner of the Night Owls
Although design quality is always a huge factor in the printing process, another growing factor for some is how to print in a more environment friendly way. To be more &#;green,&#; do you need to move away from the traditional plastisols and toward water-based inks?
Colette Wilhelm, owner of Contract Impressions in Cape Coral, FL, says that while water-based inks are touted as being better for the environment, they&#;re in fact, acrylic based. &#;However, they can give customers the great designs they crave, with a better &#;feel&#; to the shirt,&#; she says. &#;We also recommend water-based inks for clients when it helps enforce their brands&#; eco-friendly messaging.&#;
Let&#;s take a closer look at the benefits of water-based screen-printing inks, along with some things to consider.
The screen printers who learn how to use water-based inks for vibrant, full-color and long-lasting designs love the versatility of the ink and its results. Here are seven reasons why they choose water-based over plastisols.
One of the biggest criticisms of the printing industry is that the byproducts of the screen-printing process result in chemical-laden waste that you need to dispose of properly. By making the switch to water-based inks, you can reduce the impact of this waste because the inks themselves are made of more naturally occurring substances.
Plastic-based inks, by contrast, use fossil fuels, such as petroleum, to manufacture, which adds to their initial less-than-ideal environmental impact. However, water-based inks, as the name implies, are water-soluble. This means that you don&#;t need harsh chemicals to clean them up.
Tip: If you don&#;t use water-based inks correctly, they can actually be damaging to the environment, so talk to your manufacturer about how to print with them and clean up in a more sustainable way.
A huge, enduring trend in apparel is the&#; vintage&#; or &#;retro&#; look and feel in garments and decoration. That translates into a worn-in vibe, with a &#;soft hand&#;&#;where you run your hand over the print on a shirt and won&#;t feel the ink. You can achieve this with water-based inks more easily than with plastisol.
&#;My favorite reasons for using water-based ink are that it creates a softer, smoother and all-around more comfortable print,&#; Solomon says.
Even better, for many designs, after one wash, you can&#;t even feel the water-based inks at all. &#;When I print with water-based inks on white garments, you&#;re essentially re-dyeing the fabric, so there&#;s no hand,&#; Wilhelm says. &#;And remember, on dark garments, you&#;ll need to use multiple layers of underbase to achieve an opaque color.&#;
Yet, even with multiple layers of underbase, water-based inks still have less of a hand on the shirt than plastisol does. &#;This can be very beneficial to certain markets, such as for athletic and team wear clients,&#; Wilhelm says.
One great benefit of water-based inks is that they&#;re easier to mix. Your mixing systems can make just about any color you need, while also letting you control the color&#;s opacity.
&#;Water-based inks use liquid pigments, making them easier to measure and mix for color-matching purposes,&#;Wilhelm says. &#;They&#;re also easier to clean out of the screen, as you can just rinse them with water.&#;
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&#;Water-based give you vibrant, full-color designs in high detail on apparel,&#; Wilhelm says. And that&#;s great because your customers expect a sharp, bright-colored print that doesn&#;t bleed or look faded around the edges. When they see a virtual mockup, they expect to have the final print look as close to what they originally saw on-screen, as possible.
Since water-based inks soak into the fabric instead of being printed on top of it, they tend to last longer. Screen printers report that plastisol-inked designs tend to crack and fade over time, as washing and wearing chips away at the ink.
This includes low-solids, high solids, discharge, reflective, polyurethane and more. &#;I also love the versatility water-based inks offer, since there are so many different things you can do to your ink, to elevate your print,&#; Solomon says.
Tip: If you&#;re new to water-based inks, you can reach out to a vendor like Ryonet or Atlas Screen Supply for a crash course in the different types of inks available.
Many customers today are interested in supporting environmentally conscious companies. By making the switch over to water-based inks and more eco-friendly apparel, a decorator can promote the environmental benefits of these inks and increase more brand loyalty from &#;green&#; customers.
&#;There&#;s a market perception that these inks are better for the environment, which is beneficial to certain shops and certain clients,&#; Wilhelm says. &#;This can be a major sales point.&#;
Solomon points out that to print water-based inks correctly, you first need to understand the science and physics of screen printing. &#;When you&#;re just learning, having the ink evaporate or dry on the press is a tricky hump to get over,&#; he says. &#;But all of these considerations lead to positives once you master them.&#;
Basically, if you&#;re using water-based ink, then you&#;ll have to specially coat your screens so they can be used with this type of ink. This means they&#;ll need to be post-exposed, or you&#;ll have to use a special cleaner for water-based inks. (These cleaners are harder to reclaim and will take longer to work.)
&#;The emulsion remover uses water as a carrier to help it permeate the emulsion layer, making the screen resistant to water ensures that the emulsion remover will take longer to work,&#; Wilhelm says.
Most water-based inks won&#;t air dry naturally and those that do aren&#;t of the best quality for professional printing. In order to dry quickly, you&#;ll need to add other chemicals to the ink. Unfortunately, this means that the ink will only be good for less than 12 hours. So, once you add the chemicals, you need to either use the rest of the ink, or lose it.
&#;There&#;s a &#;magic trio&#; we use when printing with water-based inks,&#; Wilhelm says. &#;That trio is fixer, retarder and reducer.&#; Fixer helps the ink to adhere to the fibers of the fabric, retarder slows the drying of ink in screens, and reducer reduces the viscosity of the ink, so it flows through the screen better.
&#;Every shop will need to determine for themselves what percentage of each additive needs to be used in conjunction with water-based inks,&#; Wilhelm says. &#;Those percentages will be based on that shop facility&#;s unique temperature, humidity and production levels.&#;
Another consideration with water-based inks is that you&#;ll need to tend to the ink, so it doesn&#;t dry in the screens. If you fail to do this, you could end up with ruined screens, clogged up with dried ink.
&#;Water-based inks cure by removing all the water from the ink, leaving behind the colors,&#; Wilhelm says. &#;In a dry shop, you may have problems keeping the ink wet in your screens. Remember, if the ink does dry on the screen, you won&#;t be able to use the blocked screen until you reclaim it.&#;
Solomon also notes that water-based inks typically require larger equipment to print and cure correctly, which can get expensive.
Another consideration is that water-based inks tend to be stickier than plastisols. Because of this, they may stick to the back of the next screen and pull up the ink in the process. &#;Your design won&#;t look great, as you&#;ll have a reduction in color and increased opacity,&#; Wilhelm says.
To fix this, you&#;ll have to do more flashing to keep the print from peeling. The stickiness may also require more screens or extra revolutions on the press. All of this can increase the production time and is dependent on your shop&#;s press setup.
&#;However, it&#;s important to remember that water-based inks aren&#;t as tricky as you might think,&#; Solomon says. &#;You need to shift your mindset though and think about your projects in a different capacity. Like any other tool in your shop, water-based ink will show where you have flaws in your process. This will make you a better printer, if you put in the time and effort.&#;
In general, it&#;s difficult to exactly color match water-based inks to Pantone (PMS) colors, due to the inks&#; opacity. However, using certain additives can make the process easier. Unfortunately, that&#;ll also make the inks less eco-friendly.
Experienced printers say skilled color matching comes down to experience. &#;PMS color matches are definitely possible with water-based inks, but you need to test, test, test,&#; Solomon says.
&#;Be aware that many of the &#;recipes&#; for water-based inks aren&#;t verified to be a perfect color match, even on white,&#; Wilhelm. &#;That&#;s why a strong understanding of color theory is required to mix water- based inks.&#;
You must be mindful of your emulsions when using water-based inks. It&#;s imperative that you use a water-resistant type as these inks will destroy other emulsions (and ultimately your stencil).
&#;Water-based inks destroy standard emulsions with the friction of the squeegee,&#; Wilhelm says. &#;Use an emulsion specially designed for water-based inks, or add diazo to your existing emulsion, and post expose to ensure you&#;re using a stencil strong enough to stand up to the ink.&#;
None of these are difficult steps, but if you primarily use plastisol, you can easily miss one. &#;Then, you might ruin an entire order when the screen breaks down mid-production run,&#; Wilhelm says.
As we said earlier, water-based inks aren&#;t just made from water. They also contain solvents and pigments, as well as potentially dangerous chemicals. Because of these additives, you can&#;t simply pour the inks down your sink to dispose of them. They must be treated as hazardous chemicals.
&#;Between the amount of solid acrylics in the ink itself and the addition of the additives to give the best results, these inks are really no better for the environment than plastisol inks are,&#; Wilhelm says.
It&#;s certainly important for all businesses to begin looking at their environmental impact. One way that apparel decorators have been encouraged to help is to make the switch to water-based inks. Although this is certainly a viable option used by many shops, it does come with some considerations you must take into account before making a switch.
&#;I make sure my clients understand the pros and cons of all of the ink types,&#; Wilhelm says, &#;so that as they communicate with their end-user clients, they have the ability to direct them to the best ink for their specific needs.&#;
Are you interested in learning more about water based pigment ink? Contact us today to secure an expert consultation!