Posted by Nancy Grossbart
When a gas is captured inside another material or resin, you get foam. Because the resin is filled with gas, it makes it expand like a balloon filled with air. This creates many beneficial characteristics such as being lightweight and, sometimes, soft with cushioning capacity. Foams that are made from a plastic resin, start as a solid and then are turned into foam by creating a "gas phase" with a foaming (blowing) agent.
The foaming process begins by creating thousands and thousands of gas bubbles in the melted plastic resin. These thousands of bubbles cause the cubic volume of the base plastic resin to expand as the bubbles increase in size and number. The resulting foam can be open cell foam or closed cell foam.
The next step is for the plastic resin to begin the process of hardening, fixing the shape and size of the bubbles. Foams may be soft and flexible (flexible foam) or hard and rigid, depending on the base resin that is used to make the foam.
When a foam shell wall forms from a rigid material like most metals, plastics, or ceramics, it acts like a tiny ping-pong ball providing lighter weight material. In other words, it has a higher volume-to-weight relationship (lower density) than the same material without a foam shell. This lower density is an important property that plays a key role in many industrial applications such as floatation and insulation, which currently are substantial markets. However, when a shell wall forms from flexible material like rubber or elastomer, it acts like party balloons and provides extra cushioning or softness to the material as well as more volume-to-weight ratio. It can be used in the athletic and furniture industries. Other industries also benefited by the usage of flexible polymeric foams are automotive interiors, seals and gaskets, footwear, medical aid devices and packaging.
You can foam almost anything, if you can find an application that needs it: metal foam, polymeric foam, paper foam, wood foam, and ceramic foam have been developed and used in a variety of products for unique advantages to enrich our lives or to explore the mysterious universe.
In terms of practical perspective, foams can be viewed in three categories; properties, technologies and ingredients.
In general, foam properties can be defined by dimensions, density, softness, cell size, number of cells per cubic volume, shape, and other properties such as surface appearance.
As for technology, it is basically classified as three types of manufacturing: soluble foaming, reactive foaming and melt/solution quenching.
When producing flexible molded foams you will find huge benefits in using some ingredients like polyolefin elastomers (POE). They are known for their flexible characteristics with benefits such as:
- High Durability and Abrasion/Scratch Resistant:
- Chemical Resistance
- High Weathering and UV Stability
Flexible foam can be created in sheet form or by an injection foam molding process. The main difference is that the injection foam molding process produces a "finished part" at the end of the foaming process. The foam molding process that produces a sheet still needs a secondary "fabricating" process to turn it into a usable part.
Learn more about "Understanding Injection Molded Flexible Foam". Download our 8-page white paper.
Posted by Nancy Grossbart
It's amazing how much you can learn about subjects that you thought you had no interest in.
I majored in anthropology in college and never used any of it after I was graduated. My career had been exclusively in the marketing, advertising and graphic design area until 1999, when we came up with the idea to manufacture Injection Molded Foam parts with this incredibly unique process.
In the past 10 years on the job, I have gained a deep understanding of 3D geometry, production, quality, testing and standards, distribution/shipping and foaming materials.
Gaining this kind of knowledge is good for business because it allows you to walk and talk the talk. And if you are the least bit verbally adept, you will find potential customers asking you questions about your background that can shock you.
I have been asked more times than I can count if I am an engineer. This question has always made me laugh. Me? An engineer? Obviously, the answer is no but I must be doing and saying something right or why would people ask.
My favorite, however, is when Ron Snyder (Croc's CEO) asked me if I was a Polymer Chemist. OMG. That one really made me roar with laughter (on the inside). We were sitting on a boat in a Miami harbor beginning our relationship with Crocs. I was trying to remain professional so I didn't laugh out loud. At this point, I guess I had learned a lot about foaming materials, enough to "convince" a highly experienced and intelligent person to believe that I knew what I was talking about.
It's a perfect example that, if you want to, you can always step out of your comfort zone to learn the most complicated things.
I'd love to hear about the job you have that you were not qualified for when you started!