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Table Of Contents:
- EVA Midsole Benefits
- EVA Midsole Meaning – What is EVA Exactly?
- EVA and Ortholite
- How is EVA Made?
- Lightweight EVA Midsoles
- Quality Brands Using EVA Materials
- Drawbacks and Solutions
- Is EVA Safe?
- Is EVA Toxic?
- Is EVA Foam Eco Friendly?
- What Is Phylon Foam?
- EVA Sole Versus PU Sole
- EVA Sole Versus Rubber Sole
- EVA Sole Versus Leather Sole
- Injection Molded Versus Compression Molded EVA
- Compression Molded EVA (CMEVA)
- Injection Molded EVA
- Which One Is Best?
- All About EVA
As you can read in almost all of the reviews here, most of the shoes have the famous EVA
Whether we speak of running shoes, hiking shoes, or sandals even, EVA is constantly on the list.
EVA Midsole Benefits
The midsole is that part of the shoe (sandwiched between the upper and the outsole) that provides cushioning and rebound, and it helps protect the foot from feeling hard or sharp objects. If it is well made, it will follow the foot line.
There are great EVA sole advantages for your feet.
EVA midsoles provide stability against your foot, and in that order it has to be made of material that will endure all challenges – the terrain, a person’s weight, and all possible pressures that happen during walking or running.
EVA Midsole Meaning – What Is EVA Exactly?
EVA stands for ethel vinyl acetate which is a man-made material that is considered foam.
This is a co-polymer of ethylene (C2H4) and vinyl acetate (CH3CO2CHCH2).
Precisely, it is a polymer that has wide use.
While EVA foam is highly useful for footwear, it can be used for other things as well, like suits of battle armor.
Have a look at this video to see how versatile EVA foam can be, generally speaking:
When it comes to making footwear, there are lots of companies that are using the expanded foam rubber version forms of polymer known as EVA.
So, if you’re asking yourself “What is an EVA midsole?” It’s that part of the sole that provides cushioning and goes a long way towards protecting your feet from striking the road when walking or running.
While this is about EVA midsole shoes, we felt that we’d be remiss if ortholite wasn’t briefly mentioned.
Many companies are also using a material called ortholite for ortholite insoles.
It’s a foam that cushions people’s feet while they’re wearing brands like Asics, Merrell, and Timberland.
EVA and Ortholite
EVA and ortholite shoes both provide incredible comfort and cushioning, which is vital for walking long distances.
If you consider the amount of walking you do per day, you’ll agree that the addition of a flexible, cushioning midsole is vital to the health of your feet.
Whether that’s an EVA midsole or ortholite footbed will depend on the brand you purchase.
Some shoe and boot companies sell their ortholite insoles separately. Instead of having to buy new shoes, you can toss the old insoles and purchase new ones. For example, Nike ortholite insoles can be purchased separately.
We’ve covered ortholite in depth in another article if you want to read more about it.
Replacing the insole will keep you from having to toss out your favorite walking shoes because the footbed has become compressed. It’ll revitalize your shoe and give it new life.
EVA midsoles can’t be removed from the shoe, but the addition of an EVA insole can keep your walking or running shoes from becoming worn.
Like most rubbers, EVA is soft and flexible, but also is easier for processing and manipulation in manufacturing of versatile things (midsoles included) due to its thermoplastic properties.
What makes EVA a good choice for shoes (running or anything that will flex during walking) is the “low-temperature” toughness, stress-crack resistance, waterproof properties, and resistance to UV-radiation.”
EVA is considered to be more eco-friendly, because it doesn’t use chlorine in its production, which means there is less toxicity released during degradation.
Some companies prefer using EVA as a binding agent for other eco-friendly shoe materials like jute, bamboo, cork etc.
This way, the materials are incorporated with EVA to create a shoe that will function well, and will not harm the eco system when it is no longer in use.
How Is EVA Made?
To that question, here is a quick video that will give you an up close and personal look at EVA foam molding process:
EVA materials are made of thousands of tiny bubbles joined together that hold air.
Once they are compressed, they provide cushioning, and shock absorption (as you have read, most of the reviewers claim that wearing shoes with EVA midsoles, feel as if they are walking on clouds).
That compression makes EVA an ideal material for performance footwear.
Lightweight EVA Midsoles
What makes a molded EVA footbed different and better than other midsoles, (in most cases polyurethane ones) is its lightness.
EVA has a low density, and it’s incredibly lightweight, so it is ideal for certain types of footwear where weight is a factor (you can’t put extremely heavy midsoles in summer shoes for instance).
Those previously mentioned tiny bubbles are “forcing” the cushioning to lose some of the air, and become compressed.
Of course, an EVA sole is not made to last forever, because with time (and constant use) any footwear product made from EVA will lose its cushioning and support.
Quality Brands Using EVA Materials
Among our shoe reviews, there are plenty of quality shoe brands.
Keen uses compression molded EVA midsoles, and foot beds to provide their customers with maximum support, cushioning, and protection, no matter what type of shoe it is – sandals, sneakers or hiking boots.
Teva, as well, uses EVA compressed midsoles, to create footwear for active people who need a highly shock absorbent heel, more than anyone else.
Other well-known companies like Adidas uses an EVA midsole in their shoes. Sketchers also uses an EVA sole.
Drawbacks and Solutions
The one thing that works against EVA, is its short life. Over time EVA tends to compress; users (runners especially) say that they feel their shoes go flat after a while.
But this doesn’t stop world famous shoe brands from producing shoes with EVA midsoles; the majority of good running shoes have compression molded EVA midsoles (Nike and Adidas use them too).
This usual problem is often “fixed” by compressing EVA in a pressurized mold, where the midsole forms a thick skin. This way EVA midsoles are made to last longer.
The best way to avoid this flattening of the EVA midsole, is to replace your shoes (especially your running shoes) every 3 to 6 months.
Is EVA Safe?
On the whole EVA is considered to be a very safe material. An improvement on PVC, it doesn’t have plasticizers and it does not contain BPA.
However, some countries did ban the use of EVA foam in certain products for children (notably playmats for babies).
This is not something that has been adopted worldwide and neither is it something that applies to your EVA footwear – phew!
EVA has been declared safe for use even in food packaging, production and transport by the Food and Drug Administration (FDA) so it is definitely not something you have to worry about when wearing it on your feet.
However, although EVA is considered completely safe, there are a few sensible pointers that should be followed; fortunately, most of them are pretty obvious really.
The bad news is that your EVA midsole is likely to emit dangerous fumes, but only if heated above 400 degrees Fahrenheit.
Likewise, it is pretty flame resistant, with an auto ignite temperature of 644 Fahrenheit – so no matter how hot your feet get, they won’t burst into flames!
In terms of safety, the only real concern with EVA is if you ingest it; so unless you were planning on cooking and eating your EVA midsoles, then we reckon you’re probably quite safe!
Is EVA Toxic?
Many of the health fears about EVA stem from the fact that many EVA foam products contain a toxin called formamide.
If this is of concern to you, then check with the manufacturer to see if they have used this substance in their product.
The good news is that not all EVA contains formamide and that there are shoes out there without it.
The bad news is that not all manufacturers will state this on the specifications, so you may have to contact them directly to ask.
Is EVA Foam Eco Friendly?
Recycling and Biodegradability
In terms of recycling, EVA is still not very widely recycled. However, it can be recycled, although a lot may depend on where you live and what facilities are locally available.
It might be possible to find an independent company or body who will recycle used EVA products; but you would have to check.
As for being biodegradable, it can be treated with substances to make it easier to degrade and shorten its lifespan.
What Is Phylon Foam?
Phylon is a substance which is created from EVA; to be precise, it is made from foam EVA pellets.
These are pressed and expanded in heat, then placed in a mold a second time and exposed to high temperatures.
When heated, the bubbles of air within the structure make it pliable, which is why it favored for use in sports shoes, especially.
EVA Sole Versus PU Sole
Whereas EVA is a lightweight, manmade, airy structure, which cushions the foot and molds to its shape, PU (or Polyurethane) is rather different.
PU is a hardwearing, organic polymer. Unlike EVA which will flatten with repeat wearing, a shoe with a PU sole will last much longer.
The downside of this is that it doesn’t have a ‘memory’. It is also heavier, making it less useful in footwear which needs to be lightweight, i.e. training or running shoes.
So which one is the best? Well, the answer lies in what you want out of a shoe.
If you are looking for a cheaper, lighter or sports shoe, then you almost certainly want one with an EVA sole.
This will be the lightest, the cheapest and the most airy for the task in hand.
However, if you are looking for longevity and do not mind paying more, then a PU sole is your best choice.
EVA Sole Versus Rubber Sole
EVA and rubber have many similarities; like EVA, rubber is a flexible material, which makes it superior in sports shoes, especially.
Also, like rubber, EVA can be waterproofed.
However, there are many differences also. Rubber is heavier than EVA, which is why EVA is so favored for running and sports shoes.
But if it is traction that you are looking for, then the prevailing view is that rubber is far superior – especially if you are looking not to slip on wet conditions.
In terms of breaking in, both rubber and EVA perform well, but if you are spending a long time on your feet, you might find that a rubber sole becomes less comfortable as the day wears on.
This is not something that you have to worry about with EVA, which stays as soft and wearable at the end of the day as it did at the start.
This is because EVA molds to the shape of your feet, whereas rubber springs back more.
But if you are looking for durability, then a good quality rubber sole wins every time – as long as it is treated with the respect it deserves.
Rubber has a far longer shelf life than EVA does, as a midsole, but it needs to be treated right!
EVA Sole Versus Leather Sole
On the surface of it, an EVA sole may seem to provide superior comfort. And often, it may do. However, a well-constructed leather sole can also be highly wearable – especially when it is combined with cork.
A lot here depends on the quality, depth and type of leather construction of the sole.
Put bluntly, a thin leather sole may feel rigid and less cozy, but a triple layered leather sole will be immensely wearable and also have the added advantage of lasting much longer than both a rubber or EVA sole.
In other words, you get what you pay for, and the more you spend, the better the leather sole will be.
Of course, the beauty of EVA soles is that they are relatively inexpensive and can provide quality too.
Ultimately, though, it all boils down to what the shoe is intended for. Leather soles tend to find their way into formal wear, whereas EVA is perceived as being for more casual situations.
Certainly, nothing looks as elegant as a leather sole, but it is unlikely that your sportswear will have one!
Injection Molded Versus Compression Molded EVA
Injection molded and compression molded (CMEVA) account for the vast majority of EVA midsoles (but not quite all) that you will come across.
Many shoes will feature a combination of both processes. While there are similarities, it is useful to know the distinctions between them.
Compression Molded EVA (CMEVA)
As the name would imply, both Compression Molded EVA (CMEVA) and injection molded EVA (IMEVA) use a mold.
A bit like a waffle iron, it shapes the design and detail of the EVA midsole.
Similar to a waffle iron, the manufacturer will grease the mold, making it easy for the sole to pop out and the next one go in!
In the compression molded version, the EVA is compressed into the mold and then pressure is applied. And when CMEVA comes out of the design mold, it is exactly the same size and shape as the cast used to create it.
In some ways, the CMEVA method is just like home baking, using a cookie cutter.
The EVA is cut from a block, which unfortunately leads to wasted material around the edges.
When it comes to quality of design and attention to detail, CMEVA is the preferred method for manufacturers, as it can produce stunning results.
Injection Molded EVA
By contrast, an injection molded EVA sole is a little different. Unlike the compression method, the mold used to shape it is only about half the size of the end product.
The EVA liquid is heated to a high degree and then a blowing agent is injected into the mold.
It is left for some time, and then when the mold is removed, the EVA sole literally jumps out of its shell – full sized and fully formed!
One of the best things about injection molded EVA is the fact it produces so little waste – as the material is injected into the mold, and not cut from a batch.
The exact amount of material needed can be used for each sole.
Which One Is Best?
On the surface of things, it may seem as if injection molded EVA is preferable for manufacturers to use, as it produces less waste.
However, there are sound reasons that shoemakers favor CMEVA in various situations; as mentioned, it is far superior in terms of design.
Because it remains the same size throughout, it is far easier to shape more precisely. This makes it the best candidate for a more decorative design.
Additionally CMEVA will be cheaper than injection molded EVA and also probably far more firm, so if this is a consideration, then CMEVA may be for you.
However CMEVA is likely to be a little heavier than the more lightweight injection molded variety.
The injection molded version are usually give good bounce and have extra padding and cushioning than CMEVA.
Ultimately though, it is down to your preference for which one you think works best for you
All About EVA
So, hopefully now you know a little more about ethel vinyl acetate. Understanding more about the materials we wear everyday can help us make better buying choices.
As you can see, there are no right or wrong materials; just the correct one for the right situation!
To find out more about EVA check out the link here also have a look at this short video.