Immersion
Dyed Aniline Leather
Research
Correct
information regarding the care of leather is scarce, often contradictory,
misleading, or simply wrong. Misinformation can lead to inadvertent damage to
your vehicles leather upholstery; my goal is to present clear, concise,
accurate information.
There is a
great deal of conflicting information on leather care being put out by leather
experts themselves who recommend the same products and techniques be used
regardless of the grade or the finish applied or use baffling pseudo scientific
techno speak as another marketing ploy; one size fits all is a vendor propagated
myth.
All of which
makes it difficult to find a definitive, unbiased answer. Using the correct
product is important in order to protect your car’s interior. If you keep your
cars’ interior clean, you can easily save your car for many years and it can
stay in a ‘like-new’ condition, and maintain a better re-sale value.
Cleanliness is one of the major things buyers look for when purchasing a
vehicle.
Furniture,
Motorcycle, Equestrian Automobile leather, are all different types of leather with
differing finishes and requires different care. You do need to understand some
of the basic chemistry behind the tanning and be able to differentiate between
the various finishes applied to automotive leather in able to understand how to
renovate, clean or care for them.
There are a
few different types of leather and several types of finishes applied to the
leather used for vehicles upholstery. There are also a myriad of leather care
products available, which need to be used in accordance to the type of and
finish used in for your vehicles upholstery.
That
is why it is imperative, that if you are concerned about the results you wish
to achieve, you must perform a bit of research into finding the products
suitable for your requirements.
After
various meetings and discussions with leather tanners, their research and
development teams, chemists and fat liquoring formulators and many leather care
product manufacturers I’ve gained an understanding of this versatile material
on both a practical and scientific level.
It
had always confounded me that such a simple subject has been made into
something so complicated. I have always thought that the more facts and
information you have at hand the easier it is to judge what information you are
being given. After all, how can you fully understand and properly use any
product unless you have all the facts? In
the final analysis; it’s your vehicle, your hard earned money and your choice
Materials
Technology
Automotive OEM
technology is becoming more and more complex requiring educated and skilled
technicians to work on them. As the materials used are constantly changing we
must maintain our knowledge base and utilize the correct products and
application methodologies to keep up with emerging technologies.
Automobile
manufacturers have blurred the distinguishing lines on what exactly leather is.
Premium leather is the top split of the hide. There are many so-called
‘leathers’ that are actually the bottom split (the fibrous part of the hide)
which are covered with a vinyl or urethane coating. Diagnosis
is the key, not guess work. Before deciding on what
products to use, you need to ascertain the grade of leather and the type of
leather finish applied
Be cognizant that the leather and finishes used for
automotive upholstery varies from leather industry standard descriptions and
although the names are similar the type of leather, pigmentation and finish are
often very different. Si it is very important to be
able to recognise the various finishes and materials used by OEM’s as they all
require different methodologies and products for proper care and maintenance.
Automobile
model ranges use different materials for their vehicles interiors; leather
upholstery like Aniline Immersion Dyed, Aniline Micro Pigmented, (Urethane)
Finished, Artificial leather such as MB-Tex and unfinished materials like
Synthetics and Alcantara, and sometimes combinations of products (Alcantara
seat inserts on leather seating) as well as various grades of leather hide,
full-grain, top-grain and split –grain (which is protected with urethane) all
of which require different products and applications methods.
Automobile Interior
Environment
The
interior environment of an automobile can be extremely demanding on any
material used. Temperatures range from hot dry summer days, to freezing nights.
Both high and low humidity, even air conditioning that cools, but also dries.
Leather's greatest enemies are; sun, heat, body oils, perspiration (that
contains urea as well as organic salts and acids) and body heat, which causes
acids to become more aggressive and alters the viscosity of oils, allowing them
to permeate the leathers finish, and ultra violet radiation, which dries the
hide, fades the colour by bleaching, and can cause the leather to fail by
drying out the fibres causing the urethane and / or the hide to crack.
Leather Finishes
The
leather used for automotive upholstery varies from leather industry standard
descriptions and although the names are similar the type of leather,
pigmentation and finish are often very different, as is its care. (See the article “Leather Upholstery Type
Surface Identification”)
Leather
(Fibres) Fibrils
Full-grain
leather
Is
considered among the best quality leather you can buy. Unlike other types of
leather, full-grain leather uses the whole hide rather than layers of the hide.
In contrast, top-grain leather, another very desirable product uses the top
layers of the animal hide. Using the whole hide makes full-grain leather much
thicker, and great for products that require a certain amount of durability.
It
can be made from a variety of different animal hides, but most usually is made
from cow skin. Leather can undergo complex treatment processes in order to
create numerous products. Many of these treatments may result in weaker leather
that will not wear as well. This is especially true when the leather is treated
with chemicals. Full-grain leather is desirable because of its minimal
treatments, breathability and its durability.
With full-grain
leather, the hides of the animal used are not treated significantly. Instead
they have the hair of the animal removed but they are not sanded. This can
result in some minor flaws in the leather, but these are most desired because
of their exceptional durability and their actual improvement in look and feel (Patina)
the longer they are used
The
difference between full and high-grade leather is like the difference between a
Bentley and a Dodge. They may look similar on the outside, but you'll soon be
able to tell which one cost a lot more to process than the other.
‘Aniline’
leather is very rarely used for automobile upholstery as it is not rigorous
enough to stand up to the conditions it would be subjected to. Aniline
is an immersion dye method not a leather type per se
Leather Tanning
The
first stage is the preparation for tanning. The second stage is the actual
tanning and other chemical treatment. The third stage, known as re-tanning, which
applies agents and dyes to the material to provide the physical strength and
properties desired depending on the end product. The fourth and final stage,
known as finishing, is used to apply finishing material to the surface
Proper surface care
Is
all about knowing the properties of the surface you want to treat and what
product contains the correct formulation of ingredients best suited for that
surface. Leather finishes are a very chemically complex material, and if the
product is incompatible with it in any way, it can exert a damaging effect:
finish peeling, finish cracking, color transfer ("crocking"),
yellowing, and general degradation are some of the problems that can be caused
by the application of an improperly formulated, incompatible leather treatment
product.
Immersion Dyed Leather
Quality
manufacturers use only full- grain leathers for this process because they are
by far the strongest and most supple part of the hide and, therefore, best
suited for upholstery. After the top grain leather has been removed it is
bathed in a chemical solution which stabilizes the hide and changes it chemical
structure so that it will not deteriorate. The tannery extracts the moisture,
oils and natural preservatives and removes the hair; at this stage, it's called
‘Wet Blue’. It is more supple and
pliable than vegetable-tanned leather and does not discolor or lose shape as
drastically in water as vegetable-tanned. It is also known as wet-blue for its
color derived from the chromium. More esoteric colors are possible using chrome
tanning.
Then
they put the wet blue hides into in large, slowly revolving drums with the new
oils and preservatives (Fat Liquoring) Aniline dyes in various colors may be
added to the drums at this stage, while the hide is absorbent. They are tumbled
and during that process, depending on the thickness of the leather, it can take
up to 10 hours for the new life giving liquids to penetrate all the way to the
middle of the hide. This is the step in the tanning process that has been so
improved in recent years. Finally, the leather is pressed in heated presses,
hung up to dry at a certain humidity level, sprayed with finishes and sealers
and then pressed again.
The
tanning procedures used now are permanent and create a product which will last almost
indefinitely. Previous methods employed vegetable derived tanning agents and
were not as effective in preserving the leather. If correctly done, aniline
dyes are permanent and will not rub off or ‘crock’ after the leather is in use.
Immersion dyeing should not be confused with pigmentation i.e., adding color to
just the surface of the leather.
If
the leather has been vat dyed, the leather will be saturated throughout and a
color change is almost impossible. Vat-dyed leather looks better much longer
since the color shows well after cracks form and wear patterns emerge
Immersion
dyed top-grain leather is used in prestige European automobiles - Aston
Martin, Audi, Bentley, Ferrari, Jaguar, Lotus, Lexus,, Range Rover and Rolls
Royce, US - Cadillac and high-end German automobiles
such as Audi, BMW, Daimler AG, Mercedes-Benz and Porsche . Some super expensive exotics
and luxury vehicles still use this type of leather. But due to its hard to care
for nature some vehicle manufacturers are slowly phasing it out in favour of
Micro Pigment finished leather
Identifying characteristics – due to the dye
process the colour permeates the leather and the dyes are permanent and will not rub off or ‘crock’. The leather
is absorbent and has a random shade colours
and grain pattern, lightly scratch the surface to see if it reveals a lighter
colour.
The water-drop absorbency test- water drops
will permeate the surface and darken its colour (temporarily)
Absorbency rate – Medium High
Micro Pigment
Finished Leather
Semi-Aniline
finished leather is a alternative finishes for aniline leather; using top-grain leather that is immersion dyed and
then a micro thin transparent polyurethane covering is added, which may contain
pigmentation (colour) and an abrasion resistant additive. This type of finish
is sometimes called semi-aniline and is may be offered as Milano, Silk Nappa,
Valcona (Audi) Boston, Baseball,
Dakota, Montana, (BMW) Chaparral leather and Porsche interiors.
The water-drop absorbency test- water drops
will bead
Absorbency rate – Medium
Semi-Aniline
finished leather is somewhat absorbent, which means that
any spills, body oils etc will eventually soak into the leather hide. It should
be routinely cleaned to remove light dirt and dust by using specific aniline
leather cleaner that that will clean the surface of the leather, without being
absorbed, or force the soil into the leather.
This
type of finish is 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
imbalance which would then have to be rectified. Body oils can also cause many
problems with leather of this type, as they are acidic, leaving unsightly
patches which are expensive to fix.
In
addition to regular cleaning to remove abrasive debris and oils, leather
requires regular replacement of its moisture (re-hydration) by regular use of a
damp 100% cotton micro fibre towel.
Semi-Aniline
finished leather is moisture sensitive, so avoid the use
of oil or wax-based products as they may negatively affect the evaporation and
hydration moisture balance. Aqueous (water- based) products will help to
hydrate the leather and maintain necessary moisture
The
oils secreted from your skin are slightly acidic and may cause the leathers
pigmentation to lose its colour prematurely, taking away the effect of a
premium leather interior. Removing these oils is paramount to leather care, but
limiting the amount of bare skin you expose to your seats and interior is a
great way to prevent discoloration. This type of leather
can be renovated with a pigmentation coating
Removing Stains
•
Surface dirt and dust – use a soft
brush, vacuum and then use a clean, damp cloth
•
Spills – use a dry 100% cotton micro
fibre towel to absorb liquids, and then wipe clean with a damp 100% cotton
micro fibre towel.
•
Stains – use a mild leather cleaner
(test on an inconspicuous place before use) using very little pressure and do
not ‘scrub’ to remove
•
Water marks - wet the whole panel while
the area is still damp and this should then dry evenly. However if the water
has dried and permeated the leather leaving a hard edge no amount of cleaning
will resolve this.
•
Oil stains – should be removed
immediately, if allowed to permeate it will stain. Leather Master Leather Degreaser is applied
through a spray. It dissolves the oils and transforms them into a powder that
is more absorbent than the leather. This powder is what is wiped off, cleaning
and degreasing the leather. Allow the white powder to dry fully. If the powder
is drying to a yellow colour, it means that there are still a lot of oils in
the leather.
·
For resistant strains specific cleaning
product are available, but be aware that certain stains may not be removable,
i.e. dye transfer from leather belts and jeans, coffee, penetrated sun tan oil,
food sauces, citrus fruit drinks, etc are especially difficult to remove. On
this type of leather anything that is allowed to permeate the leather may stain
it permanently as it is not possible to clean out of leather.
·
Clean accidental spills right away, do
not allow liquid to soak or ‘heat set’ into the leather. It is very important
with this type of leather to use a protective aqueous (water- based) type
protection product, which will inhibit dirt and body oils etc from being
absorbed into the leather in the first place; these can then be cleaned from
the surface easily. Micro pigmented leather fades at a faster rate than
protected leather, so ultra violet (UV) protection is of paramount importance.
Aniline Leather
Care
Simple
cleaning, hydration and protection are the three steps that will prolong the
life of Micro pigment finished leather. Always
pre-test the product on a hidden area. Shake the foam container thoroughly.
Spray the product at a distance of 12 inches from the leather to one section at
a time, and allow product to remain in place for approximately 15 to 30
seconds.
Aniline finished leather doesn’t require conditioning
or rejuvenation; just keep the surface clean and hydrated.
1. Cleaning -
there are two cleaning-related factors that can cause your leather to wear
prematurely. The first is dirt, and the
second is oil, combined they become very abrasive, as dirt / grit and
subsequent friction cause the finish to wear
Remove
surface dirt and dust, cleaning the seams periodically is important as dirt /
grit will abrade the stitching causing them to fail, prise them apart, then use
a soft brush, vacuum and then use a foam cleaner, one section at a time, and
then finally wipe off with a clean, damp 100% cotton micro fibre towel
The
advantage of foam over liquid is the minimum amount of moisture, very important
for cleaning absorbent and moisture sensitive leathers.
Use foam cleaner, which should be given dwell
time and then gentle agitation with a medium stiff bristled brush to get the
product into the materials surface, the low moisture content of foam can then
be easily rinsed and the surface dried.
Remove excess product and debris with a clean, damp 100% cotton micro fibre
towel. If the foam is allowed to dry the soil will be re-deposited to the
surface. Check the results and repeat process as necessary
For
heavily soiled areas use a foam cleaner (Leather Master™
Foam Cleaner) that contains a surfactant that will
lift dirt and soil, allow react time to do its work and then use a soft brush
to agitate and loosen the dirt (Swissvax Leather Brush) especially on light
coloured leathers; this enables the cleaning of the micro pores and creases and
lifts the dirt out and reveal any further work that needs doing (dye transfer,
stains, etc)
2. Hydration – when leather
tanner’s talk about conditioning leather they are referring to its moisture
content, re-hydration is used to restore or maintain fluid balance
(transpiration and evaporation of moisture); not the replenishment or
replacement of the fat liquoring, oils and / or waxes.
Moisture
balance is a sine qua non (an
indispensable and essential action) in leather care. Leather naturally absorbs and retains
moisture vapour, meaning it’s also susceptible to losing the moisture necessary
to keep it pliant and soft. One of major attribute is its ability for
transpiration (allowing the movement of moisture back and forth (evaporation
and hydration), which it does even better than wool.
Repetitive
heat cycling causes the leather to lose moisture, resulting in the formation of
creasing or surface cracks, which may lead to the leather contracting; however
the urethane remains stable, which may lead to it delaminating.
A
regular wipe down with a damp towel on a regular basis is all you need to
condition and / or hydrate finished leather, and by using aqueous (water- based) products that
do not contain oils and/or waxes, check the label if they do then don't use
them. Leather should be hydrated on a regular basis and is somewhat climate
dependent.
Patina - Leather Master™ Soft Touch - is not a
conditioner per se but a water-based product used for revitalizing and
restoring the tactile feel of older leathers and also to improve the feel of
stiff leathers
3. Protection -
is essential as it will protect the surface finish, without hindering
transpiration, while acting as a sacrificial layer; this way you are not
actually cleaning the Leather's original surface, but cleaning from the surface
of the protection. It also makes dirt easier to clean off
Leather Master™ - Protection Cream (a Scotchgard™ type product specifically
formulated for lather) the polymers penetrate the surface of finished leather
and cross-link to form a durable protective film that is breathable, allowing
transpiration and keeps the leather supple. Being aqueous (water- based) it restores moisture to
finished leather and provides a protective sacrificial barrier against all kinds of soiling, water, oil, alcohol-based stains and
perspiration marks, so you are cleaning the protective layer
Swisswax Leather Glaze -drastically reduces signs of wear and ensures that new
leather remains new and in mint factory condition. A colorless protective
layer, which drastically reduces any signs of wear on the driver’s seats, side
bolsters, steering wheels and shift knobs are places where the leather
undergoes the most noticeable wear - even on new cars. It noticeably reduces
surface friction and gives added protection from jeans discolorations
3a. Ultra violet (UV) protection - 303® Aerospace Protectant will provide
invaluable ultra violet (UV) protection
against photo degradation (fading); especially in a roadster or
convertible vehicle, steering wheel and dashboards
Is water-based and will provide invaluable ultra violet (UV)
radiation protection against photo
degradation (fading) protection;
especially in a roadster or convertible vehicles. It doesn’t contain
silicones, so it won't attract and capture dust. You should apply to a clean
surface (it doesn’t contain any cleaning agents)
It will not prevent finished leather hydration (transpiration and evaporation of moisture)
as it’s water-based, although it coats the leather with a micro fine coating;
it will not seal it per se.
Note: this product does NOT air dry. Use a second dry cloth to finish the
application process. Extra buffing with
at dry cloth increases bonding, repellence and durability
Maintenance:
Monthly: Hydration of leather upholstery in most southern states;
Florida, Texas and Arizona, and etc especially during the summer months, would
not be out of line
Leather Master™
Soft Touch - apply and allow to dry for approx 20
minutes, finally using a clean dry 100% cotton micro fibre towel buff to a
matte sheen.
I hope this article has helped you to
understand that little bit more about the leather finish in your vehicles
upholstery and how to care for it correctly
Associated Articles
1.
“Reference sources and bibliography used for leather articles” - http://www.autopia.org/forum/autopia-detailing-wiki/138755-reference-sources-bibliography-used-leather-articles.html#post1474865
2.
“Leather Articles Hyperlinks” http://www.autopia.org/forum/autopia-detailing-wiki/141973-leather-articles-hyperlinks.html
3.
“Aniline Leather (Micro pigment) Cleaning
and Care” http://www.autopia.org/forum/autopia-detailing-wiki/137167-aniline-leather%3B-cleaning-care.html#post1455011
I would like to think that these
articles become an asset to anyone who is new to detailing and to professionals
alike, as well as industry experts who seek to advance their knowledge.
I hope the above article was
informative. By having some understanding of the ‘What’ and ‘Why’ as well as
the ‘How’ along with a little science to help you understand how the chemicals
we use react, you can achieve the results you desire.
I would appreciate it if you would share this article
as it helps other detailers further their knowledge.
Questions and/ or constructive comments are always
appreciated.
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© 2002 - 2012 TOGWT® (Established 1980) all rights reserved
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