Posted by Nancy Grossbart
I was thinking back over my last ten years in the injection molded (EVA and polyolefin foam) business, and wondered which products made with this process are my favorites. It's an extremely hard question because there have been lots and lots of products made. Many products have been made by my company but other companies in our industry have also created incredible designs. If I had to narrow it down to only five, which five would it be?
It was hard to decide, but here's my list. I'm sure, however, that I will need to do another post for the runners up.
Crocs Sandals. The Crocs Sandal is the number one obvious choice. It’s not only because of the incredible (so ugly, it’s beautiful) design but because of the worldwide phenomenon it created. We were lucky enough to manufacture Crocs in our factory and it never ceased to delight me to watch them being made. After they came out of a hot mold, the sandals were cooled on a unit that looked like a ferris wheel, where each level held one cycle of production. Round and round they would go and, at the end of the cycle, they would be removed from the carousel. Straps were attached and "voila" a new pair of Crocs was born, in a rainbow selection of colors.
Backpack Padding. If you’ve owned a backpack, especially a high-end backpack, you probably never noticed the comfort-foam included in the product. Why? Because it was always hidden behind fabric or mesh. The ability to injection mold EVA and polyolefin foam changed all that. Here’s a backpack that is wearing its lumbar and upper back comfort-foam on the outside, as a showpiece. The detail of the injection molded foam process allowed for industrial design to not only deal with the practical, but also the beautiful.
Kayak Seat. Traditionally, kayak seats were made from compression molded foam with a fabric laminate. This product design has always had a limited life. Several years ago a few kayak companies were adventurous enough to recognize the durability and detail benefits that result from the application of the injection molding foam process. They designed kayak seats that were not only very detailed with undercuts and logos but extremely durable.
Carseat Armrest. Check out this really creative foam carseat armrest. The carseat manufacturer designed the armrest foam to be injection molded separately and allowed the foam to "shrink" onto a plastic substrate. The subtrate has ridges on it that create a "grip" relationship between the foam and the plastic. The results ended up utilizing the benefits of EVA/polyolefin foam in an armrest application that needed to be "kid friendly."
Construction Kneeling Unit. I don't know if I like this product more because of its design or because of its function. I'll bet if you just looked at the product on the left you would never know it was used in construction. 
This clever kneeling pad design allows workers to stay on top of a house during roof construction as they are installing one truss after another. The time savings in crane rental is up to 40%, paying for the product almost the first time it is used. The orange support is made of durable, powder-coated aluminum. The injection molded EVA/polyolefin foam padding provides comfort for knees and legs and stays dry during use.
If you have a favorite, I'd love to hear about it. If you send me a photo, I will be happy to post it. In the meantime, visit our product solutions gallery to see a selection of products we've made over the years
Posted by Nancy Grossbart
The most interesting products can be made from the injection molded EVA foam process. The process was originally created to manufacture midsoles but over the last 20 years, it has become so much more. Even when we don't make the part, we love to see great design using our process.
My favorites this week are some of the latest designs from the footwear company, Native Shoes. (I also love fun shoes.) They are made 100% injection molded EVA foam; that means both the sole and the colorful uppers. EVA foam is closed cell which means they are washable, antimicrobial, and odor resistant. It is really lightweight which could be plus depending on where you're walking.
From a designer’s perspective, molded EVA foam can be ideal when a design needs to be expressed in really vibrant colors. The foam's ability to create saturated colors gives a designer the confidence to really "break out" when using this foam. Obviously, that's what makes Native Shoes so dynamic looking.
Whether you’re wearing the slip-on (one-third Vans and two-thirds Crocs) or the hiking boots, these shoes are really made for walking as the molded EVA foam will contour to your feet as the foam warms up, making them extra comfortable.
As far as I’m concerned it’s another fantastic design utilizing a process that I have grown to love. Visit our product gallery if you want to see some other fantastic designs.
I been looking on the web to buy the boots but they don't seem to be available yet. When they do become available, someone let me know so I can get a pair. Which color should I get? Hmmmmm.
Posted by Nancy Grossbart
Almost any resin can be foamed. The world of foam is made from many different resins yet the injection molded foam process uses EVA, in combination with polyolefin elastomers. Why is that? Because it makes soft foam parts!
Hard or Soft Foam? There are many other polymers like polypropylene, polyethylene, or polystyrene which can easily be foamed creating a lower density, lighter product. However the results will stiff and hard as they are hard and stiff resins to begin with.
EVA produces flexible foam. EVA is a polymer that is similar to an elastomer because it can be made to be soft and flexible. That's the origin of the term flexible foam. This means that when soft EVA is manufactured, the resulting foam will also be even softer and pliable, allowing the production of varied soft foam parts to be used in industries such as juvenile, outdoor, sporting goods, kitchen and bath to name a few.
How does it work? In a simplistic sense, any formula combining EVA and polyolefins will have a linear chemical makeup. Under normal circumstances, having a linear chain creates a harder material. However, because of the specific chemical makeup of EVA it won't crystallize easily, helping it to retain its softness. In addition, EVA foam can be crosslinked, which will both help to stabilize the foam as well as produce soft foam final parts.
Crosslinking creates stable soft foam. Basically crosslinked foams, like EVA foam, are more stable than similar highly expanded un-crosslinked foams. This means it can retain its foam structure at temperatures approaching the melting point of the polymer used and, in some cases, exceed it. One of the additional benefits of parts made from EVA foam, and other crosslinked foams, is the ability to create parts by compression molding methods, including the injection molded foam process.
Why EVA foam is a perfect resin for our injection molding manufacturing process? It produces soft EVA molded parts that are stable, durable, closed cell, and chemically resistant.
Learn more about "Understanding Injection Molded Flexible Foam". Download our 8-page white paper.
