Twin Wall Plastic Sheet Printers Guide

All Coroplast sheets for screen printing have been electrostatically double treated by "CORONA DISCHARGE" surface treatment on both sides to allow specifically formulated inks to adhere. These inks react with the surface to provide a cross-linked chemical bond; in effect becoming part of the sheet. Corona treatment will deteriorate slightly over long periods of time, but sheets more than two years old have been successfully printed.

1. We recommend that ink tests on Coroplast plastic be carried out before the actual production run to ensure proper adhesion and drying procedures.
2. Because Coroplast is non absorbent, it is necessary to lay down a minimum film thickness of ink in order to expedite the drying and increase the speed of production. For this reason the finest mesh suitable for the type of job being printed should be chosen.
3. Direct emulsion screens or indirect photo-films are recommended on a fine monofilament fabric (i.e., 190 to 305 mesh). This combination will contribute to both a thin film print for optimum drying and also maximum usage of the ink.
4. Squeegee pressure should be normal and the squeegee itself should be sharp when printing broad areas to help compensate for the fluted surface of the Coroplast. When printing film halftones or transparencies, the squeegee should be medium to sharp.
5. Use only the recommended solvents for the inks you are printing. The use of other solvents not compatible with the ink formula can create printing and adhesion difficulties. Many solvents are hygroscope - they pick up moisture. Water in the solvent can cause "fish eyes" on the finished print or other adhesion problems.
6. Coroplast is a rigid sheet and can best be printed on flat bed types or semi-automatic or automatic presses.
7. When force drying in conventional screen jet-driers, temperatures should not exceed 100 degrees F (43 degrees C). Higher temperatures will tend to warp or distort the Coroplast sheet.
8. Inks should be printed at a viscosity slightly higher than would normally be used for printing paper stocks. Approximately a 10% reduction is a good starting point. If the ink is too thin it will tend to spread in the flutes and will affect the normal sharp printing qualities of the ink.
9. The use of compatible halftone base is suggested when printing fine halftones or transparencies. This is a heavy bodied clear which adds to the printing properties of the ink when extended for fine detail printing. Halftones finer than 65 line are not generally recommended on Coroplast and a test is recommended if this becomes necessary.
10. Although Coroplast can be pulled from any direction, for best results we recommend that you pull in the flute direction.

NOTE: For additional technical support contact your ink and equipment manufacturer.

Receiving & Storage of Coroplast Plastic Sheets

Coroplast uses state of the art packaging techniques: however, we recommend that...

• Coroplast sheets shipped in the winter may arrive chilled through to the center. Please allow time for the sheets to warm to room temperature before printing or die-cutting. Condensation on cold sheets in a warm room will cause ink adhesion problems.
• Upon receipt of a shipment, all pallets should have the straps cut and removed.
• Coroplast sheets should be covered with a poly film while in the warehouse.
• NEVER store Coroplast sheets on their edges. Always store Coroplast sheets flat.
• NEVER place a large size pallet of Coroplast on top of a smaller size pallet of Coroplast. When stacking one pallet on top of another , use a 3/4" plywood or pressboard sheet between the two pallets. This protective divider sheet must be the full size of the pallet.
• Avoid storing Coroplast near exterior vents, hot pipes, sprinklers or heating ducts, or directly in front of a forced heat fan.
• The top and bottom sheets on all pallets are dunnage sheets and not counted as part of your order. Please do not try to use these.

Don't be fooled by look-alikes!

Appearances can be deceiving: however, the proof is in the performance. There are no substitutes for Coroplast When you need corrugated plastic, ask for the real thing -Coroplast!

For additional Technical information contact Coroplast.