Manufacturing rubber compounds is a lot like baking a cake: it all comes down to having the right recipe. And just like any good recipe comes from a good chef, a high quality rubber compound is devised by a skilled rubber chemist.
A rubber chemist’s job starts when they receive an ASTM specification from a manufacturer. That spec dictates the needs of the finished rubber compound, from required hardness, strength and elongation, to necessary ozone and temperature change resistance. From there, the rubber chemist sets about crafting a compound that meets three challenges:
- Design for Application: The compound must satisfy the requirements of the ASTM spec.
- Design for Manufacturability: The compound must retain its desired characteristics after being processed in the manufacturer’s facility.
- Design for Market: The compound must be the lowest cost possible while still achieving 1 and 2.
Creating a compound that meets the necessary requirements on paper is different than creating one that satisfies real world conditions. Ensuring the manufacturability of a rubber compound means walking it through the manufacturing process it will undergo—be that extrusion, molding or some other process—and seeing how the compound reacts in use. A skilled rubber chemist understands compounds, chemical interactions and end use applications—in short, they understand the process of turning raw rubber into a finished part.
To begin their work, a rubber chemist will mix rubber in one or two pound batches, testing each until they hit upon a compound that satisfies all three design challenges. From there, they’ll typically move up to a full batch, then continue to scale up. As they do they’ll make sure that the proper mixing time, mixing temperature and weigh ups (the weights and percentages of each component of the rubber compound) are observed. A rubber chemist will follow their compound through the mixing process, and often through the rubber manufacturer’s own trial process as well.
Rubber chemists play an integral role in the manufacturing world. Wherever a rubber part is involved, the process of manufacturing that part began with a rubber chemist. Right now there is a shortage of skilled chemists in the rubber industry. The ones who have reached retirement age are often paid to stay longer as anxiety builds about a shortage of new chemists entering the field. As we discussed in a past blog, the task of motivating the next generation falls to all of us currently working in manufacturing. Spurring students to pursue careers in rubber chemistry will ensure that the rubber manufacturing industry stays strong for years to come.