Here's an
extraordinarily detailed article on Nappa leather. You won't likely find this kind of information on any other website than that of TOGWT:
Friday, 28 July 2017
Semi-aniline Leather (Micro-Pigmented (MP)
Other so-called semi-aniline leather use top-grain leather; Milano, Silk Nappa, Valcona (Audi) Boston, Baseball, Dakota, Montana, (BMW) Chaparral, Range Rover Vogue are examples of micro pigment leather. Transparent, not even milky or translucent dye is added to an opaque medium, the opacity y remains, although some colour is added, and the net gray-equivalent brightness is always reduced because a dye can only absorb light. (See also Aniline (Immersion Dyed) Leather) Actually many desire the semi-aniline finish in full-grain leather because it gives a more natural look to the leather.
Using advanced micro pigments this finishing technique makes the finish rigorous enough to stand up to the conditions it would be subjected to in an automobile. These come in several variations and usually have a very fine (micro) coat of pigment to create the colour or effect and then sealed.
Generally speaking, micro pigment style leathers come in very earthy natural colours, incorporating a small quantity of pigment (a thin clear sealant that provides a uniform colour and affords some protection) but not so much as to conceal the natural characteristics of the hide so it will still retain the soft hand of Aniline leather. This type of leather is also used for perforated leather finishes.
Micro Pigment
Is a term used by the auto leather industry to better describe leather with a thin urethane layer of pigment coating, which provides an even colour and abrasion resistance. As opposed to the mislabelled Aniline leather (aniline is a dye (immersion) method, not a leather type), which will absorb body oils and moisture and would be subject to abrasion unless it has been treated in some way.
More often used for automotive upholstery as it is more durable than uncoated aniline whilst still retaining a natural appearance Semi-Aniline leather surface coating containing a small amount of pigment in the base coat, this surface coating helps impart greater stain resistance. The increased durability is provided by the application of a light surface coating which contains both pigment (colour) and an anti-abrasion additive, this ensures consistent colour, imparts some stain resistance and helps with the abrasion of entering and exiting the vehicle
Generally speaking, micro pigment style leathers come in very earthy natural colours, which may incorporate a small quantity of pigment (a thin clear sealant that provides a uniform colour and affords some protection) but not so much as to conceal the natural characteristics or feel of the hide. Other colours (i.e. gray, black, etc) have a pigmentation coating added. Transparent, not even milky or translucent; added to an opaque medium, the opacity remains, although some colour is added, and the net gray-equivalent brightness is always reduced because a dye can only absorb light.
This leather is also used for perforated finished leather. A full aniline immersion dye is one method of tanning to achieve a desired, natural looking hide or leather. Because the finish is transparent and shows the natural markings of the leather, only top quality hides can be used. The aqueous (water- based) pigmentation allows for evaporation and replacement of moisture (hydration) staying cool in the summer and warm in the winter.
Identifying characteristics - generally speaking, micro pigmented style leathers come in very earthy natural colours, and is coloured all the way through with a transparent dye. It is absorbent and has 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 pigmented 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 (rehydration) by regular use of a damp 100% cotton micro fibre towel. Micro pigmented 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 leather 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, a specific cleaning product is 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.
Three Step Micro pigment 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 the product to remain in place for approximately 15 to 30 seconds.
Micro pigment leather doesn’t require conditioning or rejuvenation; always keep in mind that you’re dealing with the finished coating on the leather and not with the leather hide itself
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 a 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.
Soft Touch (ex Vital) - 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 leather) 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
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
It’s 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 a 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 the upholstery of your vehicle and how to care for it correctly
Associated Articles
“Reference sources and bibliography used for leather articles” -
http://www.autopia.org/forum/autopia...ml#post1474865
“Leather Articles Hyperlinks”
http://www.autopia.org/forum/autopia...yperlinks.html
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