If rubber could talk, it would label us humans “ingrates”! We all realize the importance of steel and iron in our daily lives and indeed these metals are highly valued. But what about rubber?
Without the elasticity and the tensile strength of this material, our modern world would be strangely dystopian. Everything from blankets to telephone housings to driving gear depends upon the unique properties of rubber to accomplish the tasks they are meant for.
The topic of this succinct post however is not solid rubber. It is the better, improved, more resilient cellular rubber. The following top FAQs tell you everything you always wanted to know about Cellular rubber (and probably should have asked your supplier):
Q1. Why should you prefer cellular rubber to solid rubber?
A: Solid rubber is created in the conventional way through the process of vulcanization. However cellular rubber is different because it has a defined cellular structure. It is created using gas developing agents which introduce air, thus making the material less hard and dense but more heat resistant and absorbent. Cellular rubber, in comparison to solid rubber has lesser density and thus less cost implications as material (mass) per unit volume reduces. (Mass = Density * Volume)
Q2. What is the difference between open cell and closed cell rubber?
A: The two main varieties of “cellular” rubber are:
- Open cell or sponge rubber in which the distinctive cells are open and interconnected to the neighboring cells. This pattern allows air and moisture to seep in easily, giving this rubber its absorbent quality and the ability to regain its physical form after compression (compression set)
- Closed cell or expanded rubber which doesn’t allow the seepage of fluids. This rubber is cheaper and has the ability to stay afloat in water which can’t violate its structure.
Q3. So what is foam rubber and how is it different?
A: The most popular foam rubber example is PVC. Foam rubber is created using a set of processes that are slightly different from the production of sponge or open cell rubber. In case of foams the air (or gas) bubbles are actually trapped in the substrate of pliant rubber, instead of merely creating pockets within the structure because of the disturbance their passage makes. Foam can be predominantly open cell or closed cell. Though in most cases it is a combination of both!
Q4. What are compression set and compression deflection?
A: Compression set is defined as the property of rubber by virtue of which it can regain its original physical form after being exposed to compressive forces. Thanks to the pockets or cells in sponge rubber, it has excellent compression set.
Compression deflection on the other hand is the force required to compress a unit volume of rubber. Expanded rubber has no pockets whatsoever and a high value of compression deflection.
Q5. What are tensile strength and elongation?
A: Tensile strength is expressed in terms of force per unit cross sectional area of the rubber required to rupture it.
Elongation is an associated term that measures the increase in the length of the specimen with respect to its original dimensions, upon application of the tensile or breaking stress. Right when elongation stops, rupture or breakdown of the cellular structure begins.
Cellular rubber is a modern miracle and can be defined in terms of other specifications like ability to absorb shock, floatation capacity and fluid immersion. But these basic concepts should be enough to help you choose the kind of rubber you need for your manufacturing ventures.