31 / 05 2016

Ebonite and Dexonite

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Natural rubber in its raw state is not suitable for manufacturing purposes; it’s unstable becoming malleable and sticky when warm and hard and brittle in the cold. To create a more stable material rubber can be vulcanised, with the addition of sulphur or other equivalent curatives.

The process of vulcanisation was accidently discovered in 1839 and Charles Goodyear received a patent for vulcanising rubber in 1844. Since then scientists have worked hard to find further improvements for rubber, until synthetic rubbers were created followed by plastics. Despite the emergence of plastics rubber, natural and synthetic, is still widely used today almost two centuries on.

Since its creation, vulcanised rubber has been sold under the brand names ebonite or vulcanite. Ebonite is a very hard rubber that contains between 25% and 80% sulphur, as well as linseed oil. It derives its name from its intended use; as an artificial substitute for ebony wood. A vast array of products has been made using ebonite, from clarinet and saxophone mouth pieces to bowling balls and hockey pucks.

Dexine Rubber Technologies, established in 1895, developed its own form of ebonite, with the brand name Dexonite. This was used to mould many items including pipes, flanges and valves. In the early years ebonite was such an important part of its product range that the company was originally called the Dexine Rubber and Ebonite Company.

In its 1917 advertisement Dexine declared: “Dexonite supersedes vulcanite, takes a fine thread, tools easier, is not brittle, a perfect insulator. Supplied in rods, tubes and sheets.” Potential customers were encouraged to send for a sample and ask for a quotation for items made in this new material that is “easily turned and tooled”.

A century later ebonite has been replaced in most applications by newer, stronger plastics that are cheaper to make. However Dexonite is still used to line acid tanks and in some specialist components. Throughout the decades, natural rubber has been improved and synthetic rubbers created; Dexine continues to play a vital part in the industry as it develops products to meet its customers’ requirements. As an early example Dexonite has definitely stood the test of time.