TDS Weeton 728A 728B EN.pdf
Weeton 728 is a two-component polyurethane adhesive for various film/film and film/metalized film laminates. This product has good flexibility and good transparency, can effectively reduce the characteristics of aluminum transfer, and prevent the phenomenon of tunnel.
Properties
| Product Name | 728A 728B |
| Mixing Ratio | 20:4(mass ratio) |
| Solids Content | 75±2% 75±2% |
| Viscosity | 2000±500mPa.s (Brookfield LVT Rotor 2 / 30rpm,25 °C) | 2000±1000mPa.s (Brookfield LVT Rotor 2 / 30rpm,25 °C) |
| Solvent | Ethyl acetate Ethyl acetate |
| Flash Point | -4°C -4°C |
| Color | Colorless to yellowish |
Directions for use
- Dilution: Suitable solvents are ethyl acetate, and Methylethylketone provided that the water content does not exceed 300 ppm. Do not use aromatic or alcoholic solvents.
- Preparation of Adhesive Mixture: After having added the right quantity of solvent to 728A and having achieved the required solids 728B has to be stirred into the 728A/solvent mixture.
- List of Dilution: When the ethyl acetate is used for dilution, to obtain an accurate solid content, it is required to refer to the following solvents.
| 728A | 728B | Solvent | Solid Content | Viscosity |
| 20KG | 4KG | 21.0KG | 40% | 8-11s |
| 20KG | 4KG | 27.4KG | 35% | 7-10s |
| 20KG | 4KG | 36.0KG | 30% | 6-9s |
| 20KG | 4KG | 48.0KG | 25% | 5-8s |
Viscosity is based on the average viscosity of the Zahn Cup 3# (25°C)
4. Pot life: The ready-for-use adhesive in closed containers has a working time of about 8 hours. If the laminating machine doesn’t use adhesive, the retention time shouldn’t be more than 4 hours. Otherwise, the adhesive should be abandoned, or it may result in unstable laminated film.
Tropical area (Temperature >28°C + humidity >60%) pot life: Ready-for-use adhesive should be used up within 2 hours.
5. Coating: 728 is suitable for dry film laminating machines with smooth roller or gravure roller. Before mass production, repeated trials should be carried out to determine the fitting roller.
6. Application weight: Depending on the film or foil combination and the end use of the laminate, the adhesive weight may range from 2.0g/m2 (dry). For printed laminates the weight has to be adjusted accordingly, it should be approx.0.5-1g/m2 higher than for unprinted films.
7. Dry: The laminating machine should have good air volume, wind speed, wind pressure and the appropriate temperature to avoid residual solvents. Temperature setting generally follows gradient principle (55°C-65°C, 65°C-75°C, 70°C-85°C). Adjust the temperature of the oven according to the performance of the processed products, raw materials, processing technology.
8. Pressure adjustment: An appropriate increase in laminating temperature and pressure can improve the bonding effect and surface finish of the laminates.
9. Curing: Stored in a curing chamber (45-55°C), the laminates will be ready for cutting in 24h. The curing time should be extended if the laminates are used for bagging.
10. Film properties: The completely cured 728 polyurethane film is transparent, odorless, elastic and aging-resistant.
Product certification
728A/728B are suitable for laminating food packaging materials in accordance with US FDA 175.105 and Chinese GB- 9685. After sizing, the fully cured adhesive material complies with the EU 2002/72/EC and its Supplementary Agreement 2004/19/EC on the restriction of migration of certain substances.
Storage/Transport
Storage: 728 have a storage life of 9 months when stored at a cool and dry place in unopened containers. Once opened, containers of 728A/728B should be closed tightly again and the material should be consumed within a short period.
Transport: For details please refer to the corresponding safety data sheets.
Packaging specifications
728A:20KG/bucket
728B:4KG/bucket
Notes
When using 728 an efficient exhaust hood has to be installed to the coating unit due to safety reasons. The exhaust efficiency has to be checked prior to production by gas analysis for isocyanate concentration in the air. Safety regulations with regard to the handling of isocyanates have to be followed as per the guidelines issued by the International Isocyanates Institute. Please also refer to the local safety instructions as well as our safety data sheet and contact Huitian for analytical support.
As the adhesive contains polyisocyanates any contact with skin has to be removed.
Others
Film particularly the types and content of slip agents in LDPE, MDPE and CPP films, film thickness, packed goods, printing inks, pre-treatment, and film coating are of significant importance to the end use of the laminates and may affect the performance properties either directly or indirectly. Therefore, practical laminating tests as well as checks on the laminates are necessary before going into full-scale production.
Huitian is your reliable partner and satisfies your need for adhesives!
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728 2K Polyurethane Adhesive For Various Film/Film And Film/Metalized Film Laminates good flexibility & Transparency Images
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