When you look at a specification sheet for neoprene, hardness, density and other characteristics are usually listed for reference. Every application that utilizes neoprene rubber is unique and has its own specifications to be met. Critical-tolerance products like seals and gaskets require a precise combination of compressibility, temperature-tolerance and chemical resistance. On the other side of the spectrum, less critical applications like laptop sleeves just need a tough and elastic neoprene fabric material. This is one kind of neoprene that we at Rubber-Cal do not offer! Our expertise is in the solid and cellular sheet version of the rubber.

The durometer, composition, elasticity and density of neoprene rubber are determined during the processing of the rubber. Both forms of neoprene, dense sheet neoprene and spongy cellular neoprene, share the same initial processes, but they each undergo their own unique finishing methods to assume their respective forms.

Processing the dense sheet neoprene begins when the ingredients are mixed in an industrial-sized mixer. Polychloroprene, the base compound of neoprene, is mixed with bulking, pigmenting and adhesive agents. When the batch is fully mixed, the liquid neoprene mix is “dried into bits and pressed into bales”. The bales are then cut and “calendared” through a rolling mill to ensure an even and smooth consistent sheet of neoprene. Hardness, density and elasticity depend upon the types and amounts of ingredients used.

For the spongy yet elastic neoprene form, the process begins when the neoprene ingredients are mixed in a large mixer. A foaming, or chemical blowing agent, is added to the mixture, an ingredient not present in the dense sheet rubber’s recipe.

The fully mixed batch is then “baked” in an oven where the foaming agent and the neoprene react to produce nitrogen gas. This nitrogen gas expands the rubber like a delicious loaf of bread, resulting in a (inedible) bun of cellular neoprene. The density of neoprene rubber foam depends upon the additives included in the initial mixing.

Manufacturers of synthetic rubber can manipulate neoprene hardness, density and elasticity to suit any application, from automotive gaskets to foamy laptop cases. Neoprene rubber not only has a set of all-purpose physical and chemical traits but also can be processed and formed for all purposes!