Polyurethane adhesive is made of imported materials from Germany. It has the advantages of high solid content, low viscosity, good process applicability, strong adhesion, and non-toxicity. It is suitable for aluminum foil (OPA) and pretreated polyethylene (HDPE, LDPE). ), polypropylene (OPP, CPP), polyester (PET), polyamide (PA, ONY) film, metal sprayed film, two-component solvent-based polyurethane adhesive compounded between cellophane.
1. The solvent is suitable for ethyl acetate and acetone, and the water content in the solvent should not exceed 300PPM. Aromatic, toluene, and alcohol solvents are not suitable.
2. Dilution method: The solvent must be added to the main agent according to the required solid content, and after stirring, the curing agent is added to the diluted main agent and fully stirred.
3. Pot life: The pot life of the formulated adhesive is determined by the solid content of the adhesive, storage temperature and the water content in the diluent. Generally, the formulated adhesive is stored in a closed container and can be used for about 1 No obvious viscosity increase in -2 days. Adhesives that exceed the service life or the old glue in the plastic barrel will have a negative impact on the quality of the composite product.
4. Coating: It can be applied to any dry laminating machine of smooth roll and screen roll.
5. Coating amount: In order to meet the different requirements of the use purpose and material composition of composite products, the dry base coating amount can be selected between 2-6g/㎡. For composite films that require thermal processing or deep forming processing, the amount of glue applied is larger, and vice versa, the amount of glue applied is smaller. Adjust the amount of glue applied to the printed film accordingly.
6. Working density: The working density is determined according to the density of the flower roller of the amount of glue applied. The higher the concentration, the better the economy. Generally, the recommended concentration is between 25-40%.
7. Drying: In order to make the solvent on the adhesive film completely volatilize clean, it is necessary to pay attention to sufficient air volume, wind speed and temperature. For example, when the drying system is divided into three stages, the temperature gradient from the inlet to the outlet of the membrane is controlled at 50-60°C to 70-80°C or 60-80-90°C.
8. Bonding temperature: It depends on the nature and quality of the composite substrate. Use the highest possible temperature, generally controlled at 50-90°C. Films that are susceptible to temperature use 50-60°C, and other films can use 70-80°C.
9. Composite pressure: The composite pressure should be increased as much as possible without damaging the film.
10. Curing: The main agent and curing agent do not have high bonding strength immediately after compound processing. The product needs to be sent to the curing room for 24-48 hours. The working environment in winter and summer is different, please pay attention. The preliminarily compounded composite film must be cured for at least one day as much as possible before it can be rewound or made into a three-layer composite film.
11. Remaining glue: if it exceeds 8 hours or appears cloudy, translucent or thickened, it cannot be used.
