INTRODUCTIONS

Insert moulding is adopted to form 3-dimensional indication panel of the membrane switches.

The process is as shown in Fig.1.

1. The printed film is set into the moulding cast.
2. Resin is injected to the cast.
3. Film and injected resin is united and the moulded matter is formed.

To unite film with resin, adhesive binder must be put on the film.
The ink used for insert moulding should have heat resistance (180°C(356°F) x more than 1 minute) against resin-injection. It also should be flexible enough to stand embossing.
The ink with these 2 elements is two-pack type.
Thermo-setting resin that melts with heat is used to make clear ink which works as binder.