The industrial needs of our 21st century world is far more advanced and varied than they have ever been before. Many industries need special types of products for their specific applications. Foam sponge rubber is one such special product. Though classed as a form of cellular rubber, foam sponge rubber has a feel which is completely unlike most traditional forms of rubber material. It also offers a unique range of qualities which set it apart from other materials, most notably its high level of compressibility. As an alternative to more commonplace solid rubbers, sponge rubber products are used when better rates of compression and flexibility are needed. Also known as cellular rubber, it comes in open cell and closed cell variations.
Foam Sponge Rubber
History of Foam Sponge Rubber
Foam sponge rubber was discovered by accident in 1937 by the German chemist Otto Bayer. Bayer was a chemist and is known for his greatest achievement of inventing polyurethane chemistry. At the time, “Otto Bayer's basic idea of mixing small volumes of chemical substances together to obtain dry foam materials was seen as unrealistic. But after numerous technical difficulties, Bayer eventually succeeded in synthesizing polyurethane foam. It was to take 10 more years of development work before customized materials could be manufactured on the basis of his invention”. The type of sponge rubber first developed by Otto Bayer was in the form of neoprene. Today, however, foam rubber sheets can come as neoprene, nitrile, EPDM, or even a blend of different rubber compounds. Rubber-Cal recognizes that sponge rubber is crucial for a large variety of applications, so we aim to make inventory the right kind of cellular foam rubber for your needs.
How Do They Make Foam Rubber?
The first thing you will notice about foam sponge rubber is that it is not as stiff or firm as regular natural or synthetic rubber. The manufacturing process of these rubbers will determine if they are open or close cell and the different applications they are used for. For instance, “The molecular structure, amount, and reaction temperature of each ingredient determine the characteristics and subsequent use of the foam…Increasing the amount of blowing agent requires more water and a switch in surfactants to maintain optimum bubble sizes and formation rates during foaming. The density of the foam is determined by the amount of blowing” (madehow.com). Depending on how foam sponge rubber is made will determine which application is best suited for the type: open or closed form.
Properties of Foam Rubber
Rubber-Cal’s line of foam rubber sheets consists of a variety of different elastomers. This is to ensure that consumers can have the appropriate physical and chemical features of a specific elastomer for their application. We offer sponge rubber products that are made from EPDM, neoprene, and SBR as well as blends of different types of rubbers. These different forms of foam sponge rubber are created through slightly different processes. But for the most part, it involves introducing gas or foam agents into the base rubber material during the manufacturing stage to create the sponge rubber products. Each different type of synthetic elastomer is meant to give your foam sponge rubber enhanced traits and capabilities, to ensure that they meet all of challenges asked of them. For instance, rubbers like neoprene and nitrile bear a strong resistance to grease, oil and chemicals. By using these forms to create cellular rubber, the properties are passed on to the new compound. Similarly, the regular form of EPDM has a high degree of resistance to elements such as moisture, UV rays and ozone, making it a great outdoor material. These capabilities are also passed on to the EPDM version of foam sponge rubber. This ensures that the perfect sponge rubber material can be found for applications up to and including heavy-duty industrial applications.
1. What is Cellular Rubber?
The most important thing to realize is that foam sponge rubber is inherently different from its solid rubber counterpart. This difference is readily apparent in the cellular structures of both open cell rubber and closed cell rubber. This means that the material is perforated with air pockets throughout its body. Foam rubber is generally softer than regular solid rubber. In contrast, solid rubber has a molecular structure that is very closely packed together, which makes it a generally thicker and sturdier elastomer. Solid rubber tends to have a low compression rate. Foam sponge rubber, on the other hand, has a superior compression rate over solid rubber. Compression is the ability of an elastomer to revert back to its original shape after being manipulated by physical objects and pressure. As a result, cellular rubber can be great for use as seals and gaskets. However, there are a few key differences between the open cell rubber and closed cell rubber versions of foam sponge rubber.
1(a). Closed Cell Rubber
Closed cell sponge rubber products, however, are not porous. They do not have the same visible pockets that allow for liquids to pass through, meaning that it is well suited to repelling water. This means that a closed cell variant of foam sponge rubber could be perfect for use in applications such as wet suits, offering the much-needed resistance and flexibility, as well as insulation to keep the wearer comfortable. Closed cell rubber is also denser in comparison with open cell rubber and rebounds to its original shape at a slower rate. However, closed cell rubber is desirable when a better level of strength is required in your application.
1(b). Open Cell Rubber
The open cell variety has visible air pockets throughout its body. Its appearance is similar to that of household sponge items. This feature gives it a better compression rate, meaning that it will bounce back to its original form faster than closed cell sponge rubber. Also, due to the open and visible air pockets, it is a more porous elastomer that will allow liquids to pass through it easily. The open cell rubber available from Rubber-Cal is a blend of SBR and neoprene, giving it a physical durability. It also has a strong working temperature range, from -40 to 160 degrees Fahrenheit, and has a reasonable level of resistance to oil.
What is Foam Rubber Used For?
Both rubber foam types feature great levels of flexibility so that they can be adapted for a wide range of specialized uses. Foam sponge rubber has general characteristics that are shared between the open and closed cell variations. They each come in forms that have low, medium, and high rates of density, although the closed cell version tends to have superior rates of density overall. As mentioned above, sponge rubber products have varying functions depending on whether it is closed cell rubber or open cell rubber. Closed cell rubber products are more solid in nature and will provide excellent insulation and make for sturdier products in general. Due to its solid compositions, this form of cellular rubber is also more water resistant than its open celled counterpart allowing it to be used as sealants. Also, since closed cell products are sturdier, they are often used in construction applications. Open cell rubber products, on the other hand, are cushier and more absorbent than closed cellular rubber and will perform better as furniture padding, sound reduction and insulation.
Foam sponge rubber has been in use since World War II. Although it was an accidental development at first, it quickly proved itself to be a highly desirable component for use in heavy industrial applications. It played a part in America’s war effort back then and it still plays a part in America’s industrial landscape today. Foam sponge rubber has even been used outside the industrial field in the realms of commercial construction, medicine, and even fashion. People love the superior levels of flexibility and compression that foam rubber sheets offer. Available in different synthetic rubber options in both open cell and closed cell form, foam sponge rubber is the answer to your application’s requirements.