MODERN AUTO LEATHER – The Facts
Thought you guys might like a look at the reasons why coated leathers cannot and should not be treated the same way as unfinished leathers.
Most (99.9%) of leather in cars is coated (pigmented) leather. Simple water based products ( a cleaner and protector) that only take 10 minutes of your time to clean are all that is needed on a regular basis to keep them in good condition.
So why is this the case?
‘Leather is the tanned skin/hide of any animal (fish, elephant, frog, cow etc.). Once the skin/hide has been through the tanning process it can be called leather but at this stage it is in a rather unusable state and if not kept wet dries out to a stiff board like sheet. All ‘natural’ oils and fats are removed from the skin during the tanning process
At this ‘wet blue’ stage the leather is put through the re-tanning process where fat liquors are introduced and the correct moisture level is also achieved. These two combined give the leather its flexibility and suppleness. The fat liqours are good in the leather for about 20 – 30 years (not an exact length of time) and do not migrate from the leather during that time (except under some very rare circumstances which is then treated in a specific manner to resatabilise it). What does alter in the leather is the ‘moisture’ content and when tanners speak about ‘conditioning’ leather this is what they are referring to (not the replacement of oils and waxes). It is important therefore that leather is kept correctly hydrated with moisture to allow the leather to remain flexible and supple. This can be done with water based products and there is no reason or necessity to use oils and wax based products to ‘condition’ or ‘feed’ the leather. This is particularly true of pigment coated leathers (as in cars) that cannot absorb oils and waxes through their top finish anyway. As with anything in leather it is a balance that is needed. Over soaking with water will result in the fibres becoming distorted and then when they are dried will not shrink back into their previous state or position and so become hard and brittle.
Once leather has been through the retanning or fat liquoring process they move on to the finishing stage – this is determined by the quality of the hide. There is a strange anomoly in the leather industry that the more you do to a hide the less it costs. Hides with little damage are used for top level upholstery and very little may be done to finish the leather so producing aniline and other full grain leathers. Hides with a lot of damage (insect bites, barbed wire damage, scar tissue etc.) are usually buffed to remove this damage and then used for pigment coated leathers. These days split leathers (leather is split 2 or 3 times during the tanning process) are also used by bonding finishes to the leather.
It is the thickness of the finished coating on leather that detemines whether it can be classed as leather or not
If the leather has a surface coating, the mean thickness of this surface layer, however applied has to be 0.15mm or less (BS 2780:1983)
So leather is leather and is basically the same product from whatever it is produced. It is the surface coatings that we are dealing with when we are cleaning and restoring and not the leather itself.
Some leathers have very little surface coating and are very porous (to moisture and oils) but in these cases we would be trying to prevent the absorption of oils into the leather as they can cause an inbalance which would then have to be rectified. Body oils can also cause many problems with leather of this type leaving unsightly patches which are expensive to fix. Why then would we want to add more oils to the leather?
Pigment coated leather (as in most cars) needs to be kept clean. It is dirt and body oils together with abrasion that break down the pigment coating and then will begin to deteriorate the leather itself so it is crucial to stop this from happening – this can be done with protectors and regular cleaning. If oils are used on pigment coated leather (these have a layer of pigment – paint- and a clear coat finish) they cannot be absorbed into the leather the same way that moisture can and so sit on the surface and will only serve to attract more dirt so having a detrimental affect.
The furniture industry see a far more varied array of finishes than the car market so provide many more challenges to the leather specialist to solve and we are constantly updating techniques and products to suit an ever changing market
Copyright LTTLeathercare 2009
Extract from A Complete Guide to Leathercare – Judy Bass Technical Director LTT Leathercare Ltd. Leather Consultants to the cleaning and leather industry
So what is the best way to care for your leather?
For simple care of your leather interior follow this easy process
- Maintain with a 3 in 1 cleaner
- Deep clean once or twice a year
LTT Auto Kit contains all you need to care correctly for your auto leather interior