QFX is a ready-to-use, ultra-fast-exposing photopolymer direct emulsion formulated for industrial halftone and fine detail graphics printing with solvent inks. QFX has offers high solids content for stencils with exceptional edge definition. Recommended for fine detail and halftone printing. QFX resists most solvent-based inks. Stencils made with the emulsion are extremely durable, and yet can be reclaimed easily.
How To Use Emulsion
PREPARE THE FABRIC
Used or surface treated fabric need only be degreased using Screen Systems Degreaser 5505. (Mechanical roughening is an option for new fabric that is not surface treated. It increases the surface area of fabric for a better mechanical bond of the stencil, increasing printing run length.
SENSITIZE THE EMULSION
Photopolymer emulsion is fully presensitized. No sensitizer need be added. Photopolymer emulsions should be handled only under yellow safe light conditions.
COAT THE SCREEN
Use the rounded edge of a scoop coater to apply an even coat of emulsion in one pass. The coater should be at least two inches shorter that the narrow width of your screen.
Method 1:
Apply one coat of emulsion to the printing side, then one coat on the squeegee side. Dry the screen thoroughly.
Method 2:
Apply two coats on the printing side, then two coats on the squeegee side, wet-on-wet. After each coating, rotate the screen 180°. Dry the screen thoroughly. Additional coats can be applied to the print side to optimize definition.
DRY THE SCREEN
Dry multicoated screens (Methods 2 or 3) thoroughly in a horizontal position, printing side down, at room temperature in a dirt- and dust-free area. Use a fan to accelerate the drying. Avoid high humidity. Under humid conditions, dry the coated screen with warm, filtered air up to 104° F. (40° C.) in a commercial screen dryer. Use a dehumidifier in the drying area, if possible.
DETERMINE THE OPTIMAL EXPOSURE TIME
Make a Step Wedge Test to determine your optimum exposure time. Optimum exposure is indicated: _ At that exposure time when the emulsion first reaches its maximum color density, and the edges of the positive do not "resolve." _ The squeegee side emulsion is hard, not soft or slimy.
WASHOUT
Wet both sides of the screen with a gentle spray of cold water. Then spray the printing side forcefully until the image areas clear. Rinse both sides with a gentle spray until no soft emulsion is left on the squeegee side, and no foam or bubbles remain. Blot excess water from the printing side with unprinted newspaper stock.
BLOCKOUT & TOUCHUP
Blockout
For non-water-based inks, after exposure and washout, dry the screen. Apply Screen Systems No. 5511 with a plastic applicator squeegee of 14 ply cardboard.
Touchup Option 1:
Use excess emulsion and re-expose the screen.
Touchup Option 2:
For non-water-based inks, use Screen System 5511 blockout thinned with equal parts water and isopropyl alcohol and apply with a spotting brush. A block out pen will also work.
STENCIL REMOVAL
Remove ink from the screen using the solvent or solvent blend recommended by the ink manufacturer. Screen Systems Biodegradable solvent 2500 or 2550 will remove almost all inks Use Screen Systems Degreaser Liquid No. 5505 to help remove ink and solvent residues that might impair the action of the stencil remover. Brush Stencil Remover Liquid No. 6000 on both sides of the screen. Do not let the stencil remover dry on the screen. Wash the screen with a forceful spray of water. Use Haze Remover 5230 to remove ink and haze residues, if necessary.
