Type VIII - Crystal Grade
Directional property of the sheeting
The prisms that are the reflective elements of CRG have a slight directional property, the orientation of the prisms change gradually when the sheets are rotated. This also gradually changes the reflectivity, depending on the orientation of the sheets. In order to avoid difference in brightness and provide the most effective visibility, the sheets are provided with arrow marks indicating directional property. Make sure the arrow marks on the base of signs, cutout letters, border lines, and symbol marks are all horizontal.
The adhesive coated on CRG 92000 series is pressure sensitive material, the optimum application temperature is between 18°C to 35°C (64°F to 95°F).
Preparation of test pieces and Standard Curing Time
When testing the sheets by laminating them on aluminum substrates in accordance with the requirement for the test items, laminate the sheets on aluminum substrates of the specified quality and thickness that are degreased and acid-treated to prevent bubbles and foreign substances from getting in between the sheets and substrates. No matter sheet test alone or sheet test after laminated on aluminum substrates, cure them under the standard conditions of 23 +/- 1°C (73 +/- 2°F) and 50% +/- 4% R.H. for 24 hours. Conduct the tests under the standard conditions unless specifically required.
1. Adhesion test
Apply a 25.4 mm x 152 mm (1" x 6") sheet on an aluminum substrate, leaving 50 mm (2") in the longitudinal direction, and cure it under the standard conditions. Hold the test piece horizontally, and hang an 800 g (1-3/4Ibs.) weight at the end of the free sheet for 5 minutes.
Requirement: The sheet shall not be peeled off by more than 50 mm (2") in 5 minutes.
2. Impact resistance
After a test piece applied on a 76 mm x 152 mm (3" x 6") aluminum plate has cured, and an impact of 127 cm 0.45 Kg (50 lbs/in), 5.65 N is applied in accordance with ASTM D 2794.
Requirement: There shall be no cracking around the mark of impact.
Cure a 230 mm x 230 mm (9" x 9") sheet with liner, remove the liner and leave the sheet on a table with the adhesive surface facing up.
Requirement: There shall be no shrinkage in either direction of over 0.8 mm (1/32") after 10 minutes, and of over 3.2 mm (1/8") after 24 hours.
Cure a 25 mm x 152 mm (1" x 6") sheet with liner, remove the liner and spread talcum powder on the adhesive surface. Roll it on a mandrel with a diameter of 3.2 mm (1/8") and with the surface of adhesion inside in one second.
Requirement: No cracking, peeling off, or de-lamination.
This measurement should be made using an 85° gloss meter in accordance with ASTM D523.
Requirement: It shall not be below 50.
Processing method for signs
All CRG sheeting application should be at room temperature above 18°C (64°F). It is desirable to process them below 35°C (95°F), although the upper limit of the temperature varies depending on sites. Also refer to the CRG Application Manual for details.
Cutting and trimming
Cut CRG sheets individually from the front side, as they are far harder than the sheeting with glass beads. CRG can be cut with scissors and paper cutters. However, when hand-cutting or trimming the sheets, use a large retractable knife, as significant force is required, making a small retractable knife very dangerous to use. Although as many as 100 cut sheets can be piled on a flat worktable, it is recommended that they be piled with the front sides facing each other. Do not touch the front sides of the sheets to be printed; rather, hold them at the ends.
When applying multiple cut sheets to a sign board, place them with the directional property arrow marks the horizontal direction, and remember to carry out color matching. Color matching is easy when cut sheets are cut from the same roll. In addition, take each of the cutout letters, border lines, and symbol marks from the same roll or same cut sheet. It is recommended that color matching be conducted in daylight from north-facing windows in the northern hemisphere, from south-facing windows in the southern hemisphere (windows without direct sunlight), and in the color of reflected light in the dark.
CRG can be both pre-screened (sheets alone) and post screened (with substrates) using the two-component inks of the Nikkalite™ N3600 and N3800 series. These two component inks have good transparency and durability, and provide high reflectivity even after printing; also, it excels in adhesion, anti-scratch and solvent resistance. For applications that do not require solvent resistance, both the N3600 and N3800 series can also be used as one-component inks without the addition of hardener. Use plainly-woven polyester mono- filament screen with 61-71 mesh/cm (157-180 mesh/inch). Use the off-contact method for printing, and be sure to carry out fill-pass. Do not apply a large amount of ink to the screen at one time; apply it frequently in small amounts. In this way, ink can be prevented from clogging and a uniform color concentration can be obtained throughout printing. Nippon Carbide Industries Co., Inc. (hereinafter "NCI") is not responsible for any defects partial or whole, in the signs caused by the use of inks, solvents, auxiliary agents, or the like that are not recommended by NCI.
Immediately place printed sheets with or without substrates in a drying rack, and air-dry using electric fans. At least an electric-fan stand consisting of three levels each having three electric fans is required to dry the entire rack. Although tack free drying to the touch can be fully achieved in 20-30 minutes, continue to blow air for a further 2-3 hours before storing. Oven and tunnel driers can also be employed, but driers that circulate or blow hot air of 60°C~80°C (140°F~176°F) should be used. Avoid drying by heating using infrared rays or gas unaccompanied by hot air. Stack the sheets up to a limit of 50 and vertically place the sheets with substrates in exclusive-use racks, after confirming that printed sheets are completely dried. It is recommended that each printed sheet be provided with a slip sheet on the printed side.
CRG is provided with a strong pressure-sensitive adhesive with good durability, and it is recommended that it be laminated on a flat substrate. Use aluminum plates properly treated with degreasing, sanding, or acid cleaning for traffic signs that require long-term durability. When laminating on coated steel or plastic substrates, particularly on new type of substrates, confirm there is no trouble in adhesion, peel-off, swelling, discoloration and reflectivity degradation of sheeting, before starting mass production. Although the adhesion of any substrate material can be expected to be improved by wiping with solvents or sanding, confirm it by testing in advance. While CRG cannot be laminated to rounded surface, consult NCI salespersons when laminating it to curved or new material surface. NCI is not responsible for defects caused by inappropriate substrates, inappropriate surface treatment, or inappropriate lamination.
CRG can be applied using a hand roller in the case of small signs, cut letters, borderlines, and legends, and can be applied on substrates through the use of a hand or motor-driven roller applicator. When applying more than two CRG sheets on a sign, laminate them with the directions indicated by the arrow marks horizontal in the butt joint. The maximum gaps of the butt joints shall be up to 1.5 mm (1/16"). When applying using a roller applicator, adjust the nip pressure in accordance with the process technology guidebook. Excessive pressure will degrade the reflection performance. Draw positioning lines for cutout letters and symbol marks using water-soluble ink, and then wipe it off using a wet cloth.
Store CRG sheets and other Nikkalite™ products in a room temperature of 15°C~27°C (59°F~81°F) and relative humidity of 30%~60%, out of direct sunlight, and use them within a year after purchase. Avoid stacking the carton boxes in an irregular manner, and stack no more than four carton boxes of the same size in the same direction for storage. Store half-used sheet rolls with the ends of the sheeting tightly fastened to the roll with adhesive tape, either hung with plastic supporters fixed in the original carton boxes, or similarly hung horizontally with iron rods inserted through the paper core. Do not leave the sheeting rolls directly on the table or floor for an extended period. Pile no more than 50 printed sheets of the same size, with a slip sheet for each of them with its smooth side facing the printed side, and store them in a location free from dust. Store CRG products applied on substrates by standing them on square timbers or the like, so that the front sides face each other. It is recommended that a soft material such as a rubber sponge be placed between them to prevent direct contact of the sheets.
Packaging and transportation of sign faces and finished products
50 CRG sign faces can be packaged in an exclusive use box with slip sheets if the sheets are the same size and the storage directions are followed. When an exclusive-use box is not available, package them with thin plates or hard cardboard of the same size at the top and bottom. It is recommended that sign boards be packaged with their front sides facing each other, with slip sheets or cushioning materials such as foam sheets inserted between them, and placed in a wooden skeleton case. In either case, packages shall be air-permeable, with no strapping or plastic sheets that cause air-tightness. Do not apply excessive weight to the products during transportation, and do not wet the products until they are set up. In the event that the products get wet, immediately open the package and dry the products.
Cleaning of signs
In order to maintain the reflectivity and visibility of signs while maintaining long-term durability, remove dust from the signs and tar, oil, and soot from the road, and keep the signs clean. Neutral cleaning solutions are recommended for the cleaning of signs. Use chemically neutral cleansers that do not contain abrasives, strong solvents, or alcohols. Rinse them with water after cleaning them using neutral detergent. Refer to CRG's processing technology guidebook for details.