In our high-tech world dominated by silicon chips, fiber optics, and advanced synthetic
polymers, it’s easy to forget the materials that laid the groundwork for the electrical age. Long
before modern synthetic plastics like Bakelite or PVC became available, shellac was a premier
industrial material, prized not just for its finish but for its remarkable functional properties.
Today, while synthetics dominate mass production, traditional forms of the resin like button
lac continue to find critical uses in niche but vital applications, ranging from vintage electrical
restoration to the manufacturing of premium sealing wax.
The Original Electrical Insulator
In the late 19th and early 20th centuries, the burgeoning electrical industry had a major
problem: how to insulate wires, coils, and components effectively and reliably to prevent short
circuits and ensure safety. Shellac proved to be the perfect answer. It possesses excellent
dielectric strength, meaning it naturally resists the flow of electric current, and it is resistant to
tracking (the formation of conductive paths on its surface).
It was widely used to create shellac electrical varnish, which was used to impregnate the
paper, cotton, or silk windings of motors, generators, transformers, and early electronic
devices. The varnish would soak into the porous insulation material and dry to form a hard,
solid, non-conductive mass that held the wires firmly in place, protected them from moisture
and vibration, and provided crucial electrical insulation.
While synthetics have largely replaced it in mass production, the unique insulating properties
of natural resins like shellac are still valued today in specific areas:
● Vintage Electronics Restoration: Restorers of antique radios, amplifiers, and electrical
equipment use it to authentically recreate original insulating layers and finishes, ensuring
historical accuracy and safe operation.
● High-Voltage Applications: Its specific properties regarding tracking resistance and arc
resistance make it useful in certain specialized high-voltage insulator applications where
some synthetics fail.
The Art of Sealing Wax
Another historic yet enduring application is in sealing wax manufacturing. Traditional sealing
wax, used for centuries to seal letters, authenticate documents, and seal bottles, is a
composite material, not just simple beeswax.
Button lac, with its natural wax content and robust, tough nature, acts as the primary binder
and structural component in high-quality sealing waxes. It’s mixed with fillers (like chalk or
gypsum) to give it body and pigments (like vermilion or modern substitutes for the classic red
color). The shellac serves several critical functions:
● Adhesion: It ensures the molten wax sticks firmly to the paper or glass surface.
● Hardness but not Brittleness: The wax must dry hard enough to hold a sharp, detailed
impression from a seal matrix but not be so brittle that it shatters easily in the mail or
upon handling. Shellac’s unique thermoplastic properties are perfect for achieving this
precise balance.
● Meltability: It allows the wax to melt smoothly over a flame without burning and set
quickly once applied.
Conclusion:
From insulating the coils of early electric motors to forming the wax seals on premium
packaging today, the industrial uses of button lac are a testament to the enduring utility and
unique properties of this remarkable natural material. SK Shellac is proud to supply
high-quality button lac that meets the specific needs of these specialized industries, bridging
the gap between historical craft and modern application.