Base elements → Materials

PLASTICS AND POLYMERS

Plastics and polymers have long been integral to modern industry due to their versatility, lightweight, and durability. 

History

The development of plastics and polymers is rooted in scientific innovation from the 19th century onward. Natural polymers, such as shellac and rubber, have been used for centuries. However, the modern polymer industry began with the creation of semi-synthetic materials like celluloid in the mid-19th Century. In 1907, Belgian chemist Leo Baekeland invented Bakelite, the first fully synthetic plastic, sparking a revolution in material science. Following its success, advanced plastics such as acrylics, polycarbonate, and nylon begin to emerge, conquering the market and providing relatively cheap and easy-to-produce materials for diverse industries, including watchmaking

Modern engineering polymers like PEEK (polyether ether ketone) and composites integrate plastics with glass or carbon fibres, providing enhanced properties suitable for high-performance watches.

Applications in Watchmaking

Plastics and polymers are indispensable in watchmaking for both functional and aesthetic purposes. Their adaptability allows them to fulfil a variety of roles in the manufacture of watches.

  1. Cases and Bezels
    Lightweight polymers like polycarbonate and ABS are frequently used for sports and casual watches due to their impact resistance and affordability.
  2. Crystals
    Polymethyl methacrylate (PMMA), commonly referred to as acrylic, was historically used as a watch crystal material before the widespread adoption of sapphire and mineral glass. It is still used in vintage-inspired designs.
  3. Gaskets and Seals
    Flexible polymers like silicone and Viton are essential for creating watertight seals, ensuring durability and water resistance.
  4. Straps and Bracelets
    Polyurethane (PU), silicone, and other elastomers are popular choices for watch straps, offering comfort, durability, and design flexibility.
  5. Tooling

    6. Plastics are also valued for the production of various watchmaking tools, such as jigs, plates, and extractors, due to their low cost, corrosion resistance, and mechanical properties.

    Most used materials

    • Polycarbonate (PC): watch cases, bezels, and crystals.
    • Acrylonitrile Butadiene Styrene (ABS): watch cases and bezels for sports and casual watches.
    • Polymethyl Methacrylate (PMMA, Acrylic): watch crystals.
    • Polyurethane (PU): straps and protective coatings.
    • Silicone: straps, gaskets, seals.

    Machining of Plastics and Polymers

    The machining of plastics and polymers requires distinct techniques compared to traditional materials like metals or ceramics:

    1. Cutting and Milling
      Plastics are generally easier to machine due to their lower hardness. However, their low melting points necessitate careful thermal management to avoid deformation or melting during cutting or milling.
    2. Injection Molding
      Many watch components made from plastics, such as cases and straps, are produced via injection moulding, which is efficient for large-scale production.
    3. Surface Treatments
      Polymers often require coatings or treatments to enhance their durability, UV resistance, or scratch resistance, adding steps to the manufacturing process.

    Restrictions and Inconveniences

    Despite their numerous advantages, plastics and polymers have limitations and challenges in watchmaking. Compared to metals, many polymers are prone to scratching, discolouration, and degradation over time when exposed to UV light or chemicals. Many plastics deform or degrade at high temperatures, limiting their use in high-stress applications or harsh environments. While polymers can mimic some finishes, they often lack the premium feel and visual appeal of materials like stainless steel or ceramic, which are preferred in luxury watches. Finally, plastics are often criticised for their non-biodegradable nature, and their production sometimes can require significant resources.

      Benefits for Watchmaking

      Plastics and polymers provide a host of benefits that make them valuable in horology. They are lightweight, which significantly reduces the weight of a watch, improving comfort for the wearer. This is particularly advantageous for sports watches. Plastics are generally more affordable than traditional materials, making them ideal for entry-level watches and mass-market production. Plastics can be moulded into complex shapes and dyed in virtually any colour. Engineering plastics resist corrosion and chemical degradation, making them suitable for watches used in harsh environments, such as diving or industrial applications. Finally, by modifying polymer compositions or adding reinforcements (e.g., carbon fibre), manufacturers can tailor material properties to meet specific functional or aesthetic requirements.