Application of water-based polyurethane in vacuum blister:PVCThinThe film is addingDuring the heat softening process, it is close to the glue-sprayed medium density fiberboard and is vacuumed away.PVCThe air between the film and the MDF film relies on atmospheric pressure to tightly adhere the PVC film to the MDF. This process is called vacuum blister.
true The blister process is widely used in the manufacturing of computer desks, speaker panels, cabinets, doors and furniture, and is widely used in the processing and manufacturing of automotive interior parts. The biggest feature of this process is that it does not require spraying paint or coating. Paint-free process. In addition, it can cover concave and convex grooves, curved edges, and hollow carved parts, which is unmatched by other processes. The adhesive used for vacuum blister is vacuum blister glue, which is mainly water-based polyurethane glue and mixed with other trees. fat. In principle, hot melt glue and solvent-based glue can also be used, but water-based glue is non-toxic, odorless, affordable, and suitable for mechanized operations. Vacuum blister processing is developing rapidly, Japan45%of medium-density fiberboards use vacuum blister coating; my countryPVCComposite processing of medium density fiberboard has reached3000Ten thousandm2, and every year8％The above rate is growing.
1 Performance requirements for vacuum plastic suction
Vacuum plastic blister adopts spray gluing, so the viscosity of the vacuum plastic blister adhesive is required to be moderate, able to adapt to changes in winter and summer weather, and capable of spray atomization. In addition, the vacuum plastic blister adhesive must have the following characteristics:
1) It has good flowability and the surface after blister is clean and free of pitting.
2) High solid content and quick drying.
3) The initial viscosity is good, especially at the grooves and edges. The initial viscosity of the plastic blister is particularly required to be good.
4) Good heat aging resistance, at least60℃hour,24 hoursAfter baking, the film will not curl, shrink or bubble.
5) The activation temperature is low. The use of water-based polyurethane glue must have an activation temperature. The activation temperature is required to be within65～75℃within the range, the temperature is too high,PVCMembrane is prone to perforation