1. Composite sheet forming method
The molding method of PC/PMMA is as follows:
Extrusion compounding: refers to the composite material obtained by extruding a raw material onto another formed film during the processing of the film.
Adhesive type: refers to a composite material obtained by compounding two different kinds of films which have been produced by a binder.
Co-extruded composite film: Co-extrusion compounding uses several extruders to simultaneously squeeze different kinds of resins into a composite die. Each layer of resin is integrated into the die or foreign exchange, and is cooled and shaped after extrusion and compounding. That is, it becomes a composite film.
2. Main features of coextruded composite film
The composite film is extruded at one time, and the process is simple, energy saving, high production efficiency, and low cost.
The composite film is soft and comfortable to the touch.
Since there is no need to use an adhesive between the layers, there is no problem of residual solvent, and the film has no odor.
At present, the research of the hotter composite board is a two-layer composite material obtained by co-extrusion, PMMA is used for the outer layer and PC is used as the inner layer.
3, Typical performance parameters
Light transmittance is 91%~92%;
Pencil hardness is 1H;
Tensile strength is 50~60 MPa;
Tensile modulus of elasticity is 2000~2600 MPa,
Density is 1.2 g/cm3.
As a mobile phone case, PMMA has high hardness and wear resistance, so it can be used for the outer layer of the phone cover. However, due to the brittleness of the composite, the composite PC acts as an inner layer, so that the toughness of the material as a whole is improved. Through surface hardening treatment, the surface hardness (4H-6H) of PMMA can be improved, wear resistance 0000# steel wool, 1 kg force, 1 cm×1 cm grinding head, 5000 times intact.
Touch screen, lens sheet:
Touch panels, Lens and other window lenses, mobile phones, tablets, display lenses, mobile phone buttons, membrane switches, etc.
Smart leather case thick plate:
PC/PMMA composite sheets can be used as a protective cover substrate for smartphone designs. Excellent machining performance and thermal fit to achieve a variety of visual effects.
IMD in-mold decoration and in-mold insert FIM:
PC/PMMA composite sheets are suitable for a wide range of high pressure and hot pressed IMD/FIM molding processes. Automobile control parts, interior parts, various types of instrument panels, mobile phones, monitors, bags, helmets, etc.
After the surface of the composite sheet is hardened, it can be used for the cover of the mobile phone after 3D high pressure molding and texturing.
There are only a handful of equipment manufacturers for the production of PC/PMMA composite sheets, so they mainly rely on foreign imports, and there is a lot of room for localization.