• Casein: dyed and double cut

    Casein identification guide: casein is a thermoset semi-synthetic polymer made from milk, hardened in formaldehyde

    4. Can be dyed either in the plastic batch or on the exterior. Carvers took advantage of this to create 2-color designs.

    source: Button Materials A-Z: Identification Guide
    by Jocelyn Howells

    Button Specs