Leather uppers, one for the mythbusters?

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salutations to you all (most of you anyway)............. I have just perused another patient handout and it included the old "furphy" that leather made the best upper material because it "breathed"..............apparently the modern synthetics are comparable to leather re porosity and permeability....what (another word for "stuffs" in here) the passage of moisture out, up and away is the use (amount thereof) of adhesives to adhere the linings to the uppers..............cameron kippen where are you?, mark conley

 

Just put some eyelettes in the arch of the quarters on the upper and anything will breathe.
These eyelettes are available from any hardware store (wilkos in the UK) with the grips to punch holes and another to attach the eyelette.
Alternatively, tell your pts to go to the shoe menders who will put them in the arch for you then there is cold air coming in during swing phase and hot air passing out in the contact phase.

DF

 

Mark

I was always amused at the mention, leather breathed. Antricipation of shoes with lungs always seemed too ridiculous for words. However we know what they were implying. Shoe leather from the latter part of the 20th century has been leather treated with synthetics (plastics) to improve their appearance and performance. So technically there is no such thing now as a leather shoe.

In the good old pre plastics , leather offered a good medium for the upper because leather exhibits a high degree of plasticity. When it is stretched and held it will retain the new shape. Synthetics on the other foot will demonstrate a high degree of elasticity unless subjected to very high temperatures (rarely reached in the foot). Hence plastic uppers will accommodate the foot and its vagaries but then return to its original shape when not in use. This often meant people wearing plastic uppers were in a continual "breaking in " state with their footwear.

Cameron
Hey, what do I know

 

Does leather breathe ?
Generally leather consists of three layers of body cells. The epidermis, a fatty bottom layer - adipose or flesh, and the middle layer of skin, the derma or corium, the corium is what is used for leather which is composed of collagen fibrils bundled into filaments and fibers.
The epidermis is "scraped" off and the adipose "fleshed or fleshing" then it is split to the required thickness.
The next process is tanning, you have mineral tanning resulting in a porous leather, vegetable tanning, used for many years til present for the uppers (not always, depending on type of shoe to be made and from what source) resulting in a pliant leather. You also have chrome tanning used for shoe soles (again not always) as this results in a sturdy hard leather, usually bovine.
After this a false grain is applied "laying the grain."
There are many other processes than above but you are left with are fibres.
To say that this cannot breathe after tanning is not ridiculous for words.
As far as synthetic uppers, this is PVC made by a process called "flow moulding" and was fashionable during the mid 80's as it was cheap to make a pair of uppers. The plastic was moulded to the shape of the "whole" upper with patterns incorporated such as the appearance of stitches, the look of a brogue golosh or oxford for instance.
They did not last too long as the foot couldn't breathe and we all walked around in very wet feet.
As far as leather being treated with plastics to improve their appearance this was applied in the finishing room of the factory, not during tanning. A cellulose or wax is applied to give a shiny appearance and quickly wears off.

Cameron stated,
"In the good old pre plastics , leather offered a good medium for the upper because leather exhibits a high degree of plasticity. When it is stretched and held it will retain the new shape"

Well Cameron, during the design of the shoe they draw the thing, nice and easy, it is then past to the pattern cutters. They tape up the last with masking tape and draw on this. A few technical bits later the paper is removed from the last so you have a left and right side. It is from this template that the upper is made, having the counter at the back, the quarters at the sides, the vamp at the front and the tongue.
Added to these are the lasting margin which tucks underneath the last during back part moulding, forepart moulding and side lasting and it is this portion that the sole adheres to.
During closing of these components (stitching together in the closing room) the shoe has already its shape, which was cut for a particular last. To reinforce this, in the making room (where the uppers, soles, insoles, etc all come together from different rooms) a toe puff is applied beneath the vamp and when heated during lasting it will shape itself to the curvature of the last and on cooling will retain that shape.The same process happens with the counter. After this and the upper has been lasted around the last and stuck to the insole but, before applying the sole, it is past through a machine (heat moulding or lasting) that heats it to over 100 centigrade. then the lasting margin is roughed, primed and adhesive applied then the sole stuck on and the last removed.. (different manufacturing process for welted) and it is these processes starting from the pattern cutter that retains the shoe shape.

You also stated that
"Synthetics on the other foot will demonstrate a high degree of elasticity unless subjected to very high temperatures (rarely reached in the foot). Hence plastic uppers will accommodate the foot and its vagaries but then return to its original shape when not in use".

During "flow moulding" the synthetic is liquified then dried to a particular design/pattern for a particular last ? it will retain this shape indefinitely unless reheated.

You do have in many shoes a lining beneath the upper which may be synthetic and can affect the foot breathing but, nowadays again these are made to breathe.

Dermot Fox BSc(Hons) Podiatry
Podiatrist and qualified shoe maker.

formerly Purchasing Manager for 10 Factories at British Shoe Corporation (became Burlington International) and Factory Manager at County Footwear Npton and 4 years training at Wellingborough College in Shoe Design, Pattern Cutting, Manufacture (including welted) and Management.

 

Is this an argument for the sake of pro or against leather and there for may represent an animal rights issue?????????????????, or are we fair dinkum. Hopefully the continued high price of oil and derivatives will make plastic ultimately too expensive and leather wil prevail. (My piortity any way)

In the end, it depends on the end use. There are not many athletic shoe types that contain leather (with off course, notable exceptions) and there are few if any orthopaedic shoe types (again with notable exceptions) that are "plastic"

If breathabilty is the only issue, that there are plenty of materials such as platizote, pulman shoes uppers, latex etc that can breath

 

i'm a serious chap caf002, as you put it it that old english dialect term derivative "fair-dinkum"...........
a bespoke footwear lecturer ~20 years ago maintained that modern synthetics were as efficacious as leather re permeability / porosity, so when i peruse a (diabetes) foot care handout and read "USE LEATHER UPPERS" i tend to get apoplectic (see "spitting mad" in the thesaurus)...... admit it's a wee small point but there you go.......
then CAMERON and DERMOTFOX were good enough to contribute with some most imformative posts.....and now your contribution, thanks and aveagooday ....