There are generally two methods of making polyester buttons.
Sheet
Sheet Casting button is made by a special centrifugal casting. Fully mixed Unsaturated Polyester Resin and other chemicals is poured into the rotating centrifugal drums (casting process). After sometime it will turn to be soft glue due to chemical reaction. Then cut into sheets. Put the sheets on punching machine to form different sizes of blanks. After the curing process, the state of punched blanks will turn into hard.
Sheet Casting buttons are producing by two types of Casting Drums:
Undulation Drum:
Only Pearl Imitation buttons are casted by Undulation drums to show the undulation effect.
Plain Drum:
All types of Sheet buttons are casted by Plain Drum.
There are many styles of sheet buttons, such as imitation shell buttons, pearl buttons, imitation wood buttons, multi-layer buttons, etc.
Rod
Rod Casting process of button making technology currently used by us is from Bonetti, Italy. Rod Buttons is poured by a W-shaped pipe. Pour the completely mixed Unsaturated Polyester resin, Pigments and other chemicals into the waxed aluminium tube (different sizes) through a special oscillator (casting process). When the resin become soft glue, pull out the resin stick from the aluminium tube (different sizes) and then cut it into slices (thickness wise). After the curing process, the state of sliced blanks will turn into hard.
Imitation horn button, imitation corozo button, etc., all belong to rod button.