As a popular elastomer used in various different applications, it is no surprise that neoprene is made in many different ways and forms. However, neoprene also comes with different names for each of these forms. To begin with, neoprene is sometimes referred to by its chemical name chloroprene, which is abbreviated as CR. One such form that has become very well known is sponge neoprene, also referred to as foam rubber. The foam version of neoprene can be further divided into two similar but distinct categories: open cell foam and closed cell neoprene foam. These spongy neoprene materials offer their own unique traits and benefits, giving the chloroprene material more useful abilities that it has names.

Before there was neoprene or even any kind of open or closed cell neoprene foam sheet, there was simply chloroprene. Chloroprene is the main material used to make neoprene rubber. The chemical company DuPont originally synthesized it in 1930. However, they did not simply use chloroprene or neoprene as a name for this new chemical and weather resistant rubber. They opted for the moniker of “DuPrene”, just in case there were ever any doubts as to who owned the material. But later on in 1937, they changed the name to neoprene.

As commercial and industrial needs advanced over the years, sponge neoprene was developed. Interestingly enough, this material is manufactured using the same process as that of its solid form counterpart. The only difference is in the addition of a chemical foaming agent, hence the name “foam rubber”. This foaming agent is responsible for producing gas bubbles within the rubber during the curing stages of its production. These gas pockets in neoprene foam sheet rubber can also be produced through a continuous whipping of the rubber mixture. The end product is then a result of about 85% air and 15% rubber

Sponge rubber is a blanket term that can indicate one of two products. A piece of sponge neoprene can be either a version of closed or open cell foam. The difference between a neoprene closed cell foam and an open cell foam is that the closed cell variety is normally sturdier while the open cell variation tends to be softer. In closed cell neoprene materials, the air particles in the material do not pop as the rubber is being created. As a result, the material contains numerous internal pores which create a stronger and more flexible rubber.

In the open cell version of sponge neoprene, the air bubbles in the particles burst during the foaming or whipping process. This results in a network of interconnected particles that gives the end product a softer consistency. It has an overall higher compression rate. If a lot of physical pressure is applied to this open cell neoprene foam sheet, it will bounce back to its original shape far quicker than most other types of elastomers, especially its neoprene closed cell foam counterpart.

While sponge neoprene rubber is great for a wide range of different applications, it does not tend to last as long as its solid rubber counterpart. This is partly because solid rubber is meant to endure more physically demanding challenges. It is simply designed to last longer. The physical structure of a neoprene foam sheet can eventually weaken over time. It can slowly lose its flexibility. Solid neoprene rubber has a good resistance to aging, but sponge neoprene does not.

Regular solid neoprene materials are often divided into two general categories: hard and soft. They possess very similar properties. They can both perform very well in the face of certain chemicals and outdoor weather conditions. The true differentiator between the two is in their durability. Hard neoprene can take a much higher degree of physical abuse than its softer counterpart. Soft neoprene is usually used in applications that require more flexibility from their components. Harder Neoprene sheets have a higher durometer, are more dense, and weigh more. Softer neoprene sheets are more flexible, supple and have better flex fatigue.

As you can see, neoprene is available to you in various different forms. The options are abundant, just like the names given to each class of the elastomer. Sponge neoprene and foam neoprene is the same thing. Open cell and closed cell indicates a sponge/foam. When you are getting a piece of neoprene closed cell foam rubber, you are getting sponge rubber. At the same time, hard neoprene and soft neoprene are both solid rubbers. Next time you are looking for neoprene materials, be sure to know which kind of neoprene you want!