Leather Upholstery; Surface Identification

[togwt]

Automotive Leather Finishes



For many, finding the best leather care product is as simple as using what is the most popular. While popularity can sometimes be a reliable barometer, it isn’t always the correct choice. Some even make their decision based on new car’s leather fragrance alone. My best advise; research other options and products, test them and then make an objective decision based upon factual information, not hype or brand loyalty.



After all, how can you fully understand and properly use any product unless you have all the facts? I would also strongly suggest that you verify any information that I or anyone else shares with you.



There are three main types of leather finish



1. Unfinished dyed leather; aniline dyes are translucent; the transparency of the dye enables you to see the natural marks on the leather. Because it’s the top-grain, this leather has plenty of physical durability.

This type of leather finish is typical of approximately 10% of vehicles



2. Finished leather has a topical water-based pigmentation coating; and then a clear coating are applied to the surface. These coating represent the colour and sheen on the leather.



3. Protected leather with a pigmented urethane coating, without the tensile strength of top-grain, consequently will have a short useful life expectancy. Split-hides are typically heavily pigmented with an abrasion resistant urathane clear coating.





The common denominator is that whatever the leather finish any product that is applied to its surface must allow evaporation and hydration i.e. the flow of moisture back and forth



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 ultra violet radiation (UVR), 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.



The most fundamental question to be answered before you clean or care for leather is to establish the type of leather finish used in the vehicle as the methodologies are very specific for each type

Always remember you are dealing with the finished coating on the leather and not with the leather hide itself

Automotive finished leather upholstery is a multi-strata urethane coating; consisting of the actual hide, colour pigmentation and the surface finish.



An acrylic and polyurethane resin binder system is used to improve flexibility, fastness and adhesion to the leather, then two or three water-based pigmented base coat applications a clear water-based top coat is then applied, which usually includes additives to give it a soft feel and a limited amount of ‘slide’ as the final stage of the finishing process.



The urethane (Ethyl carbamate) used for protecting automobile upholstery is classified as a semi-solid permeable membrane, being a thermosetting polymer (elastomers) it remains flexible while retaining its tensile strength, to enable it to expand and contract, following the temperature fluctuations (elasticity) of the substrate. The urethane although very resilient to abrasion wear from entering and exiting the vehicle, by using additives it still maintains its physical properties like flexibility, tactile hand and its patina



A urethanes fibre structure will stretch in all directions with no particular grain or stress pattern. The urethane surface coating will not withstand multi directional stress, however, and when it’s flexed or stretched continuously in the same place the surface coating develops minute cracks. It also has micro-pores that allow evaporation and hydration (the passage of water vapour through a membrane or pore) they are not sealed per se as some chemicals penetrate it easily; others stay on top dependent upon their molecule size.



Leather Upholstery Type Surface Identification



Automotive leather is a rather difficult category to define as OEM descriptions of leather finishes vary, often incorrectly from that of leather manufacturer’s description. Automobile manufacturers have blurred the distinguishing lines on what exactly leather is.



The most fundamental question to be answered before you clean or care for leather is to establish the type of leather used in the vehicle and / or finish applied as the methodologies are very specific for each type. One products suits all leather type finishes is a marketing myth



Leather finishes - there are two strata’s to automotive leather upholstery; the actual hide and the surface finish. The hides used are generally bovine, which must be kept hydrated to maintain tensile strength, luxurious suppleness and prevent the hide from cracking and becoming dry. Natural leather has a water-based pigmentation applied to the hide to provide an even colour. There is no such thing as a cow with blue, red or burgundy skin.



Automotive leather is typically finished with a coating, which protects the surface from (UV) radiation, as well making it resistant to soiling and wear. These coatings vary in thickness; Aniline leather is has a clear coating of approximately 0.2µ as opposed to covered leather, which has a pigmented layer of approximately 25 µ, applied to provide protection from wear when getting in and out of the vehicle



Leather Detailing and Care



Formulate a detailing plan, then utilize proper detailing techniques, combined with quality products is what makes a details outcome, successful. You will find that getting unbiased information on this subject is somewhere between very difficult and impossible. It is important to be able to recognise the different materials used for vehicle upholstery as some OEM use different materials for the various surfaces (i.e. perforated leather for the seating areas, PVC bolsters and seat backs)



Once you’ve correctly identified the leather and / or the applied finish applicable to your vehicle`s upholstery, it’s easier to select suitable products / methods (one size fits all is just a vendor`s marketing myth) First you need to identify the material and finishes used; Nubuck / Alcantara®, Aniline and Protected or Coated



Different types of leather require specific cleaning and care and therefore require a slightly different process. Check your `leather type` before attempting to clean or apply any products to its surface.



Leather is very dynamic with respect to its moisture content; the leather hides needs to be kept supple. The purpose of rehydration is to restore moisture lost through evaporation, so whatever the surface finish, it has to allow the movement of moisture back and forth (evaporation and hydration).



1. Micro Pigment (Semi-aniline leather) - is a term used by the leather industry to better describe leather with a fine layer of pigment coating as opposed to the mislabelled ‘Semi Aniline’. Aniline leather will absorb moisture unless it has been treated in some way. (this also identifies perforated leather)



More often used for automotive upholstery as it is more durable than aniline whilst still retaining a natural appearance? Aniline leather which has received a 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



Aniline dyed leather can be renovated with a pigmentation coating (unprotected Aniline is rarely used for automobile upholstery). 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.



• Identifying characteristics - It is highly absorbent and has a random shade colours and grain pattern.

• The water-drop absorbency test- water drops will darken the surface, but it returns to its original colour after drying.

• Absorbency rate -High



2. Protected leather (P-Protected / Coated) - by slightly scratching it with your nail, if it changes to a darker / lighter shade, it is unprotected (i.e. how suede changes colour depending on the fibres` orientation). If this has little effect it’s protected.



The majority (95% + ) of automotive upholstery is by-cast urethane (Ethyl carbamate) covered leather, these leathers have aspects of a natural finish, but more uniform in appearance, by-cast will also stretch more than top grain leather and is therefore subject to show creasing.



Cleaners and conditioners remain on the surface, it’s (urethane) protected leather as liquids other than water (due to the size of its smaller molecules) will not penetrate.



• Identifying characteristics - this type of surface; it will also have an even shine.

• The water-drop absorbency test- water drops will ‘bead’ on the surface

• Absorbency rate -Low



3. Alcantara® Ultra suedeâ„¢, Ecsaine, Micro suede, etc) are not leather and would more accurately be described as a fabric, it is in fact a synthetic materials composed of 68% polyester and 32% polyurethane, it has the appearance and tactile feel similar to that of suede, and it may be incorrectly identified as such. Toray Industries` Ultra suede or Alcantara is finding application in seating as well as dash trimming, steering wheel covering and headliners in many high-end original equipment manufacturer (OEM) automotive applications. Suede and Nubuck -suede has a napped surface and is made from the buffed inner surface of calfskin or kidskin. Nubuck is produced by buffing the exterior of the hide.



• Identifying characteristics – these materials are very soft to the touch and will scratch or scuff very easily.

• The water-drop absorbency test- water drops will darken the surface and will remain dark or leave a water mark after drying.

• Absorbency rate -High



Nappa and Perforated Leather (A-Aniline // Non-Coated) – for leather used in autos, Nappa is a term that is used to denote a high quality leather, it’s a very soft, absorbent full grain (uncoated) and usually tanned with alum and chromium salts and dyed throughout



• Identifying characteristics – see Aniline Leather

• The water-drop absorbency test- water drops will darken its colour (temporarily).



4. Vinyl - is a non-organic (synthetic) material that has an even, almost repeating pattern. Vinyl can imitate leather as they imprint a grain pattern into it; the depth of the lines within the grain on vinyl is also consistent, while the same lines on leather will vary.



• Identifying characteristics - it is also usually smooth and soft to the touch.

• The water-drop absorbency test- water drops will ‘bead’ on the surface

• Absorbency rate -Low



Alternatively go to your local vehicle dealership along with the vehicle identification number (VIN), they can advise you of the options fitted.



The common denominator for all the above surface finishes is that they all require specific products in accordance with the finish; not forgetting protection from ultra violet (UV) radiation



Artificial leather



Is a non-organic (synthetic) leather-like finish material that has an even, almost repeating pattern, it also has a protective coating applied. It also has micro-pores that allow evaporation and hydration (the passage of water vapour through a membrane or pore) they are not sealed per se as some chemicals penetrate it easily; others stay on top dependent upon their molecule size.



MB-Tex and Artico [: a plastic fabric made to look like leather] are probably the best known of this type of material that can imitate leather as they imprint a grain pattern into it; the depth of the lines within the grain that also consistent, while the same lines on leather will vary widely. Artificial leather usually has single stitching; whereas leather uses double stitching, as leather is thicker.



• Identifying characteristics - it is also usually smooth and soft to the touch.

• The water-drop absorbency test- water drops will ‘bead’ on the surface

• Absorbency rate -Low



Leatherette sometimes referred to as Poromerics (a term coined by DuPont) an imitation leather are a group of synthetic ‘breathable’ leather substitutes made from plastic coating (usually polyurethane) on a fibrous base layer (typically polyester) Including Naugahyde, the fabric can be made of a natural or a synthetic fibre which is then covered with a soft PVC layer, which is a lighter, more flexible and less restrictive material than leather. This kind of material is easy to clean, requiring the owner to simply wipe it off occasionally with a cloth dipped in a solution of mild detergent and warm water.



Periodically clean using a 1:10 solution of P21S Total Auto Wash and distilled water to remove dirt build-up thoroughly and effortlessly, these chemicals restore the original texture and resiliency; use to clean all polyurethane covered automotive upholstery; this product is biodegradable and environmentally friendly



Protection - even though this material is not real leather, it can definitely crack and distort, with Einszett 1z Cockpit Premium safely cleans all clear and coloured automotive plastic interior fittings such as dash, trim, door panels, navigation/audio screens, steering wheel, and pedals. It leaves a long-lasting matt finish with fresh citrus scent. The perfect everyday cleaner for interior plastic surfaces, it’s a mild cleaner to prevent the drying of these porous surfaces, yet it is effective at removing body oils and grime on a regular basis.



Application - Spray onto a clean micro fibre towel, agitate it well and then allow it to remain in place for 10-15 minutes. Finally using a clean micro fibre towel buff it to ensure it permeates



Three Step Care



All finishes have to allow `(evaporation and hydration) ` - the flow of moisture back and forth, the important considerations for proper leather care; is as much about (a) the state / condition of the leather you are dealing with (b) methodology used (c) product. Cleaning is a combination of all these



(a) Clean - as dirt / grit and subsequent friction cause the finish to wear.



(b) Hydrated - use water-based products that do not contain oils and/or waxes, check the label if they do then don`t use them. Clean surfaces with a damp towel.



(c) Protected - is essential as it will protect the surface finish and makes dirt easier to clean off and an ultra violet protective product (UVR) will preserve the finish.



Leather is very dynamic with respect to its moisture content; the leather hides needs to be kept supple. The purpose of rehydration is to restore moisture lost through evaporation, so whatever the surface finish, it has to allow the movement of moisture back and forth (evaporation and hydration). So the use of water- based cleaners and protectors will maintain hydration, which is essential to keeping it in pristine condition.





Related Articles



1. “Reference sources and bibliography used for leather articles� - http://www.autopia.org/forum/autopia...ml#post1474865



2. “A Brief History of Leather� - http://www.autopia.org/forum/guide-d...ml#post1463189



3. “Leather Tanning Process� - http://www.autopia.org/forum/guide-d...ml#post1455796



4. “Leather Fat Liquoring and Conditioning� - http://www.autopia.org/forum/guide-d...ml#post1462908



5. “Leather Restoration / Renovation� - http://www.autopia.org/forum/autopia...ml#post1479003



6. “Types of Leather Used in Automobiles� - http://www.autopia.org/forum/autopia...ml#post1474058



7. “Leather Surface Identification� - http://www.autopia.org/forum/guide-d...ml#post1451654



8. "Various Leather Surface Conditions and Correction" - http://www.autopia.org/forum/guide-d...orrection.html



9. "Leather care products" - http://www.autopia.org/forum/guide-d...ml#post1465895



10. "Removing Stains from Leather" - http://www.autopia.org/forum/guide-d...ml#post1468879



11. “Proper Finished Leather Cleaning and Care� - http://www.autopia.org/forum/guide-d...ning-care.html



12. "Leather Conditioning" - http://www.autopia.org/forum/guide-d...ml#post1454835



13. "Using Oil-based Leather Care Products" - http://www.autopia.org/forum/guide-d...ml#post1450942



14. “Aniline Leather; Cleaning and Care� - http://www.autopia.org/forum/guide-d...ml#post1455011



15. “Perforated (Nappa) Leather; Cleaning and Care� - http://www.autopia.org/forum/guide-d...ml#post1455017







[Edit: Retailed Articles list added to 05.19.2012]

[rdorman]

So what was used in a 2000 BMW 740? Nappa?

[togwt]

So what was used in a 2000 BMW 740? Nappa?

What did the `water-drop absorbency tests` confirm?



A ‘fall-back’ position for leather care if you are unsure of the finish is to use a foam type cleaner (Leather Master™ Foam Cleaner) provide surface protection (Leather Master™ - Protection Cream ) and always ensure that the surface is hydrated by using a damp 100% cotton towel