3M security foils are specifically designed for tamper-evident labeling. In an undamaged state, they are equipped with a non-visible “VOID” inscription, which remains adhered to the substrate when removal is attempted. This inscription appears as a blank space on the foil. Labels made from this material cannot be transferred without being destroyed.
3M security films are equipped with a modified acrylate adhesive and are therefore also suitable for bonding to difficult and low-energy substrates such as polyethylene, polypropylene or siliconized hammer finish coatings.
All products in this series can be subsequently labeled with variable information.
| Product | Color | Foil thickness in mm | Adhesive thickness in mm | Release liner in mm (g/m²) | Release liner |
|---|---|---|---|---|---|
| 7380 | White matte | 0,058 | 300 0.020 |
0,081 (80) | Densified paper, siliconized on one side |
| 7937 | White matte | 0,058 | 300 0.020 |
0,170 (153) | Poly-coated paper, siliconized on one side |
| 7866 | White glossy | 0,050 | 300 0.020 |
0,081 (80) | Densified paper, siliconized on one side |
| 76799 | Silver glossy | 0,050 | 300 0.020 |
0,077 (90) | Densified paper, siliconized on one side |
Due to the aluminum vapor deposition, the color silver glossy is not recommended for bonding to printed circuit boards.
| Material | Polyester |
|---|---|
| Temperature resistance (bonded to aluminum) | -40°C to +120°C – no visible change 7380, 7937, 7866: -40°C to +120°C, no changes 76799: -40°C to 80°C, no changes -40°C to 120°C: The VOID lettering becomes visible, the VOID effect remains functional |
| Dimensional stability (tested according to DIN 30646) | Code number 02 (shrinkage < 0.2%) |
| Dielectric strength (VDE 0303, T2) | 80 kV/mm |
| Burning behavior when bonded to aluminum | Self-extinguishing after 15 seconds, does not drip |
| Salt spray (according to DIN 50021 SS) | 150 h, no complaints |
| Fungal resistance | fungal-resistant, does not promote fungal growth |
| Substrate corrosion | does not cause corrosion on the bonded substrate |
| Adhesive | Self-adhesive on acrylate basis, series 300, suitable for polyethylene and polypropylene |
| Adhesive type (according to DIN 30646) | PNS (permanently adhesive, low-temperature, special adhesive) |
| Minimum bonding temperature | +4°C |
According to our current knowledge, the following functionality and durability can be expected from 3M Thermoscript foils. Generally, not less than the following times with vertical outdoor weathering, if the foils have been properly processed and applied according to 3M recommendations:
| Durability | In outdoor use: 2–3 years In indoor use: almost unlimited |
| Shelf life | 2 years |
| Recommended storage condition | 23°C / 50% relative humidity. It is recommended to store the film/label rolls in polybags. |
3M 7866 and 7380 have a higher light transmission due to the VOID technology. This may require marking the release liner so that the labels are recognized by the light barriers of the thermal transfer printer.
Carelessly peeling the label from the backing paper can lead to a so-called pre-destruction effect. To avoid this, the foil should be slowly detached, maintaining a peel angle of 90°.
The strength of the VOID effect is significantly influenced by the strength of the adhesive force to the substrate. Therefore, thorough cleaning of dirty surfaces is particularly important. Full-surface and opaque printing of the labels should be avoided – the VOID effect would be invisible as a result.
| Printing | Screen / letterpress / flexographic / offset printing processes A color qualification test before series production is recommended. Note: It is recommended to test the base print for chemical resistance if necessary! |
| Die-cutting | Sharp knives and minimal web tension are recommended, to avoid possible adhesive leakage. |
| Pretreatment of substrates / bonding | See processing information KG-054 |
SFW 0.2 S DIN 50018
Stress 2 cycles: no change
Foil bonded to stainless steel, tested with 72 h storage in standard climate 23/50, DIN 50014.
The foils are resistant to most mineral oils and greases, fuels, aliphatic solvents, weak acids, salts and alkalis, such as:
| Loading agent | Loading time | Result |
|---|---|---|
| Heptane | 4 h | No complaints |
| Petroleum | 4 h | No complaints |
| Diesel | 4 h | No complaints |
| Engine oil SAE 15W40 | 4 h | No complaints |
| Windshield cleaner | 4 h | No complaints |
| IPA | 4 h | No complaints |
| Industrial cleaner (lemon) | 4 h | No complaints |
| Dish soap | 4 h | No complaints |
| Acid (PH 4) | 4 h | No complaints |
| Alkali (PH 10) | 4 h | No complaints |
3M 7866, 7380: UL File No. MH 16411
3M 7937 UL File No. MH 11410
Anfrage / Zentrale
Folit GmbH
Im Moldengraben 47
70806 Kornwestheim
Anfrage / Zentrale
Tel: 07154-8225-80
Inquiry / Headquarters
Folit GmbH
Im Moldengraben 47
70806 Kornwestheim
Inquiry / Headquarters
Tel: 07154-8225-80
