Material science

What does ESD stand for?

 ESD is the abbreviation for electrostatic discharge.  Everybody knows what that is:  we touch an object or a person and get a quick electric shock.  This happens whenever an unnoticed electric charge build-up (resulting e.g. by certain flooring) is suddenly discharged and dissipates.

Shoes with ESD-Footbeds prevent these unwanted discharges.  This is important in the workplace e.g. when handling sensitive high-frequency technology, because it can be damaged or destroyed by electrostatic discharge.  But even at home ESD-Styles are practical because quite often we get inevitably electro-statically charged by carpet flooring.  Wearing clogs or sandals with ESD-Footbed can be useful.

What does soft footbed mean?

For even better walking comfort the soft footbed is outfitted with an extra layer of foamed natural rubber.  This layer distinguishes itself by an extraordinary rebound value.  It achieves long-lasting cushioning and gives particularly sensitive feet even more care.  But of course the soft footbed is also ideal for all those who simply prefer a softer footbed.

What is Birko-Flor?

Birko-Flor is the proven upper material which Birkenstock developed for their shoes and their licensees.  The upper layer of Birko-Flor has a leather-like texture; the bottom layer is a soft fleece.  The material is very durable and easy-care.  When it’s dirty it can simply be wiped with a wet cloth and left to dry.  Birko-Flor is very skin-friendly and pleasantly moulds to the foot.
What is so special about the Birkis® soft⊕base Sole®?
The soft⊕base sole® has been specially developed by the brand Birkis® for their own shoe styles.  It is an additional shock absorbing layer made of latex which is inserted into the sole.  Uneven contact surface is counteracted by this extra latex layer in the footbed.  This makes for pleasantly soft walking on hard surfaces such as rock, concrete or asphalt. 

What is PU?

PU is the abbreviation for polyurethane.  Polyurethanes are synthetic resins or plastic materials originating from chemical compounds.  Depending on the type of production polyurethanes can be hard and brittle or soft and flexible.  In foamed state, polyurethane turns into elastic soft foam - like ALPRO®-Foam.  This material contains millions of foamed bubbles and is pleasantly soft.  Moreover, it is water proof, durable and very easy-care.  It is resistant to oil, grease and lye.  When they are dirty PU-shoes can simply be cleaned with water and left to dry in the fresh air.
Some styles can even be machine-washed at low temperatures.  ALPRO®-Foam made of polyurethane foam is skin-friendly and contains no hazardous materials.  All PU-styles can therefore be worn barefoot without hesitation. 

What is EVA?

EVA stands for ethylene vinyl acetate and describes a heat-resistant synthetic.  Ethylene vinyl acetate is generated by a chemical reaction of ethylene and vinyl acetate.  EVA is processed by Birkenstock and their licensees in the form of ALPRO®-Cell.  This material has many positive characteristics:  not only is it waterproof, it is also heat-proof, resistant to oil and solvents and in large part to chemicals.  Moreover, it has very good shock absorbing properties.  Like ALPRO®-Foam (PU) ALPRO®-Cell (EVA) is very robust and easy-care.  EVA differs from PU mainly in that it is very light weight.  Birkenstock Licensees use it mainly for beach sandals and garden clogs.  This material has also been tested for its skin-friendliness and hazardous materials.  Shoes made of EVA can be worn barefoot without hesitation.

The ALPRO® Super Bottom Sole

The super bottom sole lends many ALPRO®-styles extra walking comfort.  The special feature:  the super bottom sole is made up according to the sandwich principle.  An elastic soft layer made of EVA is embedded between the certified rubber bottom sole and the shock absorbing cork-latex footbed.  This compensates for uneven surfaces and fosters the healthy natural step formation when walking.  The oil and grease resistant tread of the rubber sole is also slip-resistant.  This means that the super bottom sole is ideal for daily use in kitchens and the hospitality industry as well as in the medical and care sector.

The ALPRO® Form Sole:

The name says it all:  ALPRO® Form soles are cast, not punched.  This has many advantages over regular soles:  The main one being that the form sole is non-marking.  This is especially important in the hospitality industry or in the medical sector where it is not favourable to leave unsightly marks on the floor.  On top of that the enlarged contact surface improves standing properties which is important in occupations where a lot of standing and walking is necessary.  Moreover, the form sole is shock absorbing, anti-slip and light as a feather.

Natural Leather

Natural leather is distinguishable by its typical varying colour scheme and surface texture.  Contrary to smooth leather in the case of natural leather surface differences are not evened out.  The natural character of the lacklustre surface remains intact.

Smooth Leather

Smooth leather has a smooth surface with very little scarring and a uniform feel.  In the case of smooth leather the scarred side of the leather is exposed.  It is resistant to outside influences and thus guarantees a long life.

Nubuck Leather

Nubuck leather is sanded or polished on the natural scarred side.  The sanding or polishing process lends it a delicate, velvety surface.  Nubuck leather feels very soft and is breathable.

Greased Leather

Greased leather is smooth leather which is treated by a greasy colour coat.  Thanks to the treatment with grease it is very robust while remaining soft.

Suede Leather

Suede leather is sanded on the meat side of the leather which yields a fibrous yet soft surface texture.  Contrary to the very velvety nubuck leather suede is markedly rougher.

What is Birko-Flor Nubuck?

Birko®-Flor Nubuck is Birko®-Flor, which receives a special finishing treatment to achieve a nubuck-like surface texture.  Birko®-Flor Nubuck not only looks like nubuck leather it feels like it, too.