Discharge Water Based Screen Printing

Discharge screen printing is becoming ever popular in todays market.  www.silkscreeningsupplies.com carries a line of discharge water based screen printing inks as well as EnviroLine water based ink that is environmentally friendly.  This blog is focused on discharge and dye discharge printing. 

Examples of Discharge Prints.

Standard Discharge	Dye Discharge: Click to Enlarge

DSPS Discharge needs to be activated by Discharge Agent which is a powder that is mixed into the discharge ink 6-10%.  You should only activate as much discharge as you will need to print at a given time as it does have a life span of about 6-8 hours once mixed.  Discharge Agent is a powder and can be ordered by the pound here.

PLEASE NOTE: YOU MUST HAVE DISCHARGE AGENT IN ORDER TO USE THE DSPS DISCHARGE SYSTEM!

To add dye into your discharge use the Ryonet EnviroLine PC 301 Pigment Inks.  PC stands for pigment concentrate and are mixed at a ratios between 5-15% (typically about 10%) into the activated discharge base. PC pigments are available in quantities of 4, 8, and 16 ounces.  

Discharge ink can be used with most 100% cotton shirts (does not work on poly or poly blend fabrics).  We recommend that you consult your shirt supplier to find out which garments SKU’s are the most discharge receptive.   Always test as results may even vary from batch to batch on the same type of garment.   

Confused about water based and discharge inks?
Here are a few helpful application charts.

Water Based Ink Type	EnviroLine WB Inks	DSPS Discharge	Discharge White	PC Pigments 301 Inks
Garment Capability	100% Cotton & Poly Blend	100% Cotton	100% Cotton	N/A
Environmental Friendly	Very	Slight Impact	Slight Impact	Mixed With: WB: YES Discharge: Some
Pantone  Matching	Yes	No	No	Yes
Required Additives	None: Ready for use.	Discharge Agent	Discharge Agent	Must be used with a base or discharge binder.
Color Additives	PC Colors for color boosts	PC Colors	N/A	Can be used with RC Inks, PC Bases, or Discharge Binders
Mixing Ratios	PC Pigments as a color boost up to 15%	Agent: 6-10% PC Ink: 5-15%	Agent: 6-10%	See Instructions
Underbase Options	RC Transparent  Opaque White Discharge   Discharge White	Used as an under base	Used as an under base	When mixing with discharge, no underbase needed.

 

Application	Type Of Water Base System	Mesh
Pantone Color Match	EnviroLine 301 RC WB Inks	156-280
Paper / Cardboard	EnviroLine 301 RC WB Inks	230-305
Towels / Canvas	EnviroLine 301 RC WB Inks	86-110
Light Garments (100% or Blend)	EnviroLine 301 RC WB Inks	156-230
Opaque Results on Dark Garments (100% or Blend)	EnviroLine 301 RC WB Inks w/ Opaque White Water Based Ink	White: 110-156 Color: 156-230
Soft Hand on Dark Garments (100% Cotton)	1. Discharge w/ RC Color Overprint 2. Discharge White w/ RC Color Overprint 3. Dye Discharge w/ PC Pigment	110-156
Vintage Look and Feel	1. RC WB Ink on Light or Dark. 2. Direct Discharge 3. Dye Discharge	Ink: 156-200 Discharge: 110-156

Ryonet Water Base Discharge does require certain safety precautions when mixing and printing.  

Read more about discharge printing and instructions for use below!

MESH:80-160

STENCIL/EMULSION: A water proof direct emulsion should be used for optimal performance. SWR-3.

SQUEEGEE: 60-80 Durometer square edge. (Ryonet recommends 60 or 70 Durometer)

MIXING:

PC Pigments: Mix 10% or less pigment with 100% discharge binder making sure to mix pigment into binder before mixing in the discharge agent.

Discharge Agent: Should be mixed 10% into 100% discharge binder (by weight).  

PRINTING: Once discharge agent is mixed into the discharge binder (with or without pigment) print directly on fabric, flash cure and print Matsui 301 Eco-Series inks directly on top (wet on wet).

Under Basing: An under base can also be accomplished by printing discharge ink, which discharges the dye from the fabric, flashing, and over printing wet on wet w/ RC Ink.  For the ultimate brilliance and soft hand results try our premixed White Discharge which has white pigment mixed in into the discharge leaving a discharged white under base.

Curing Options: Water based inks cure differently from standard plastisol inks.  While plastisol inks cure with infrared once reaching 320 degrees, water based inks cure best with air movement and heat.  Air movement is preferred to drive water out of the ink and blow away steam so heat can cure water base pigment properly. Without hot air movement across the ink, water based inks will take much longer to cure.  In good air flow, water based inks can cure in under 1 minute while it may take 2.5 to 3 minutes in a standard infrared dryer. (Paper can be allowed to air dry)

WE STRONGLY SUGGEST WASH TESTING AND DOCUMENTING CURE TIMES BEFORE BEGINNING PRODUCTION.

Level	Method	Picture	Process
Basic	Heat Gun		Heat guns actually work fairly well for curing low quantities of water base prints. Hot air from the gun forces water from the ink and curing can actually be seen as the ink dries.
Starter	Infrared Flash		IR flashes work marginally well. Take shirt off pallet, raise flash head up 4-5 inches above the shirt, cure for 2-3 minutes until ink is temped at 320 degrees. Wash test before production.
Intermediate	Infrared Conveyor		IR conveyors work decent for low quantity production. Raise conveyor gates to allow steam to exit dryer, bump temp down slightly, slow belt speed down, allow to dwell 2-3 minutes.
Professional	Forced Air Flash		Forced air is preferred for lower production or flashing. For a final cure, lift shirt from pallet to allow air to circulate under the garment.  Cure for 60-90 seconds.  Conduct Wash Tests.
Production	Air Flow Conveyor Dryer		Optimal for WB Inks, air flow gas or IR dryers can cure in 60-90 seconds depending on chamber length. Air knifes remove water from ink and IR or Gas heat cure garment.

CLEAN UP:  Card off excessive ink and dispose of in trash.  Use Sprayway Water Base Screen Opener to break down ink then wipe residue from screens, screen frames, squeegees and any surfaces in contact with ink. Left over residue can also be washed in the sink with water after soaking.

FINISHING: It is highly recommended to wash and dry garments or fabrics before packaging and shipping.

View and Download Discharge DSPS and Discharge Agent MSDS Sheets.

Water Base Discharge Inks

Discharge printing can be a valuable addition to your operation. Discharge is not a use-it-and-forget-it product. Discharge printing comes with safety precautions, issues with finished goods, and procedures for a healthy shop environment. These issues are not that difficult to deal with and cannot be ignored. Be prepared to properly handle the discharge products or don’t even try them.

Methods of using discharge

Discharge inks require an activator/catalyst to work; there are two different systems available. The predominant system relies on active ingredient Zinc-Formaldehyde-Sulfoxylate (ZFS). The newer, and less used system relies on Thiourea Dioxide as its active ingredient. There are different name determinations dependant on what the ink company calls it, in most cases formaldehyde is the active ingredient. In both systems, the ink has a limited discharge life once the activator is added. There are two methods of discharge printing, both systems can be used.

1.       The first and most traditional printing method is to discharge every color in the print; there is no need for an underbase screen. In this format you mix PC pigments into the discharge to give it color when discharging occurs.  PC pigments can be ordered in a variety of different colors and are typically mixed at about 10% into the discharge base.  This method saves a screen and does away with flashing between colors. The exception to this rule is when a black-ink screen is needed. There’s no need to use discharge if the black will cover without it. When printing on black, any black that is on the design is reversed, that part of the design will use the shirt color itself.
Example of Dye Discharge: Click to Enlarge

2.       The second method is to use discharge strictly as an underbase. With this method, you can use either white discharge or natural discharge, which contains no pigment and reveals the natural color of the fabric. The following colors are printed with regular plastisol with or without flashing.  Some prefer not to flash the discharge underbase. This saves the head used for the flash and any cool down heads. The end result is that printers can increase the amount of colors they can print on dark shirts by one or two.

The white discharge underbase works well for most design types, especially spot-color work. Even though the other colors are printed using plastisol, the overall print has a less heavy feel because the underbase is a water-based product. If a design contains halftones or other areas with very thin ink deposits, then a natural discharge would work much better. The pigment in the white discharge underbase might mix with the process inks and shift their color. This is usually a problem with spot colors.

Discharge underbasing makes true 4 color process printing on dark fabrics possible. For process printing do not use a white discharge underbase. When the white pigment mixes with the transparent process inks, they will turn pastel and muted. Work with a natural discharge underbase that will reveal the natural cotton background color using a highlight white to make the design pop. Process-ink systems can be beefed up using triple-strength versions to compensate for the natural background thus overcoming the off-white background color. Again if the design contains any white color of its own, print a white highlight that is designed to print with the process inks using this application.

Safety issues in production

Water-based ZFS-activated discharge is the most used and the most versatile method of discharge printing. ZFS has an unpleasant odor and should be handled carefully in its crystal form then blended into the ink by a properly trained employee. Always blend the ZFS slowly until it is well mixed in the ink to prevent dust, ZFS is relatively safe once in solution. Formaldehyde is a skin irritant. Proper procedure dictates dryers should be properly vented, never use an unvented dryer for discharge curing. Shirts printed with ZFS discharge have measurable levels of formaldehyde. Garments that are allowed to sit for a time after printing in an unconfined state will disperse most of the formaldehyde within days. If at all possible, avoid folding and packing ZFS-discharged garments immediately after printing.

~ by ryonet on April 22, 2008.