INJECTION MOULDED POLYURETHANE (PU)
At Begg Shoes we are big fans of injection moulded PU as a construction method. Brands that specialise in this method of construction are IMAC, Legero, Padders, Hotter & Ecco.
Ecco are the best in the world at using this construction method to make shoes, a great example of the technology they can incorporate into a casual mens shoe is their latest Cool Walk Gore-Tex Surround technology style. This style is probably the most technologically advanced shoe in the market due to the complexity of the construction methods involved.
At really high temperatures polyurethane melts into liquid form and can be injected using a high-tech machine (best imagined as a large metal syringe!) that clamps a metal mould around the upper of the shoe. The shape of the metal mould determines the shape and appearance of the sole unit. Nowadays, PU injection technology from the likes of Ecco is so advanced that the shapes & styles of shoes that can be made are remarkable. Historically, it was accepted that shoes can only be made using PU injection moulding if they are flat but nowadays they can make shoes with a heel such as the ECCO – 264023-01014 Touch 35. They can make them look like traditionally welted shoes and the ECCO– 640304-01009 Vitrus I is a really good example or even have a phased in colouring that is really eye-catching such as the ECCO – 283543-50342 Genna.
What’s good about shoes made with Injection moulded PU?
Three key words are always soft, light and flexible! A high quality grade of PU will also be extremely hard wearing (the most hard-wearing you can buy & much better than a rubber sole). In our view, at least on a practical level, injection moulded PU shoes are a must have for anybody. They will provide long lasting comfort and last for much longer than a cheap pair of shoes. Another added benefit is the bond between the upper and the sole unit is rarely if ever broken which means your shoes are highly unlikely to fall apart and the water penetration is reduced on a soaking wet Scottish day!
So what’s not to like about injection moulded PU?
Not a lot in our view other than aesthetics. You cannot make beautiful high heels with injection moulding! At least for now….perhaps Ecco have something up their sleeve to take on Gabor and Peter Kaiser!
What we call a “stitch construction” has become a really popular style for comfort shoes and here at Begg Shoes they are becoming a big hit with our customers. The method involves stitching the side wall of the sole unit to the upper using a specialist stitching machine (not just a sewing kit!). Examples of brands that use stitch construction to great effect are Rieker with their famous Celia sole unit, Walk in the City Suliflo, Relaxshoe and El Naturalista.
So why buy a shoe that is put together using stitch construction?
Distinctive style and supreme comfort are the main reasons. They are often the most flexible shoes that money can buy. Stitch construction allows manufacturers to use polyurethane (eg. all Rieker shoes are in fact PU – just they are not injection moulded). Polyurethane is always light and with the suitable density and quality is cushioned and shock absorbing. This is essentially why Rieker claim their shoes are “Antistress” – they are extremely comfortable owing often to their stitch construction, soft uppers and stitch construction. Another added benefit to stitch construction is that it is a cheaper method of construction than PU injection moulding, result is the price that you pay is often less.
Are there any negatives to stitch construction?
Water penetration in-between stitch holes is the main drawback of stitch construction. Our advice to customers to overcome this downside is to apply a neutral shoe polish / cream into the stitch holes nearest the sole unit. This area of the shoe is most exposed to potential water penetration and application of polish can massively reduce this. (This does not change product description to that of being waterproof!). Looking at the positive side of having to do this, regular use of shoe polish or shoe cream will help to extend the ‘life’ and overall appearance of your shoes.
We love this clip from ECCO Shoes showing Injection Moulded (PU) construction method of some of their shoes.
I hope you found this blog informative and feel free to contact our customer service team in Inverness for any further advice on the subject.