Leather care has always been a highly controversial subject. The main reason for this is due to the lack of advancements in the chemistry of products. The vast majority consist of outdated products and techniques that were used 25 years ago. These products were the only chemicals and methods available during that time period and were derived from products used in other industries and applications.
This creates a great deal of confusion for the consumer. Many of the products sold are produced solely from the standpoint of making a sale. This has established a poor reputation within the industry, and causes many people to conclude that it’s a waste of time and money since these products do not work as expected.
Over the five decades I've been involved with detailing the materials and production methods that are used for automotive leather upholstery have changed; and we need to adapt our product usage and application methodologies to change with them
Research
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 use baffling pseudo scientific techno speak as another marketing ploy, which makes it difficult to find a definitive, unbiased answer. It had always confounded me that such a simple subject has been made into something so complicated.
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.
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
Always keep in mind that you’re dealing with the finished coating on the leather not with the leather hide itself
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.
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. 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.
The Institute of Inspection, Cleaning and Restoration Certification (IICRC) is a reference Guide for Professional Upholstery Cleaning (IICRC S300) it’s a five day leather training course, which devotes two days of the course to the corrects identification of leather finishes. So 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.
Leather
It is hard to find an application that tests the durability and strength of leather like that of automotive upholstery. From extreme temperatures to hard, physical contact, automotive upholstery demands leather finishes that will withstand the punishment that it receives
Leather's major attribute is its ability to breathe, which it does even better than wool. This means not just its permeability to air but its permeability to water vapour, so allowing the absorption of perspiration and warmth. Thus it feels warm in winter and cool in summer, yet doesn't become hot and sticky.
On the other hand, whilst it absorbs water vapour it doesn't readily absorb liquid, so rain (but don’t allow over saturation) will not harm it and a damp cloth can be used to keep it clean
Leather is a natural product that has a matte finish, and comes from animal (bovine) hides, which have been chemically processed (tanned) to preserve them.
A properly tanned hide (or skin) creates strong, flexible material; resistant to decay. Most leather used in auto vehicles is tanned cow hide, which are laterally split, rendering an upper (Premium) and lower cut (Split-leather or by-cast). (See the article “Leather Upholstery Type Surface Identification”)
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.
Pre-test Spot Procedures
Diagnosis is the key, not guess work. Before using a cleaning product a detailer needs to know the material they are working on, what they are trying to remove and wither the product chosen is compatible with the material and will not damage it.
With all cleaning products, always test a small, inconspicuous area first to ensure it won't discolour or stain the surface, and ensure that the pH of the product is suitable for the material. As can be seen stain removal requires some knowledge of basic chemistry.
Surface checks
• Identifying characteristics
• The water-drop absorbency test
• Absorbency rate
• Identifying characteristics
• The water-drop absorbency test
• Absorbency rate
Read the product labels and manufacturers safety data sheets (MSDS) to obtain a basic idea of contents, pH levels etc. Depending on the pH of the product you use you should return the surface to neutral (pH 7.0) before you apply any dressing or protective products.
Always select a chemical / cleaner that are biodegradable, environmentally friendly and safe to use by observing any precautions recommended so that they won’t harm you, your vehicle or the environment. Read the product labels and manufacturers safety data sheets (MSDS) to obtain a basic idea of contents, pH levels etc.
Testing cleaners on an inconspicuous area is the best way to ensure there are no surprises as to its affect, but be cognizant that it may not react in exactly the same way as a heavily soiled area or that has been subjected to UV-B radiation (faded) When spraying any surface with a liquid, it is always advisable to spray a small area first (test area) then allow to dry to make sure the solution does not react with the surface.
Providing the cleaning product selected is suitable, apply several drops of the selected cleaning solution onto a 100% cotton micro fibre towel and rub gently. Do not over wet. Use small amounts of the product and blot frequently, do not rub or use too much pressure.
Do not use the product if it adversely changes the surface colour or texture.
Choosing a Leather Care Product
The most important consideration in leather care is to identify the finished leather used. 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; 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 Master Products are used as a ‘benchmark’ by other leather care product vendors. All aqueous (water- based) cleaners will remove any body oil or salts, dirt and grime and wash them from the leather surface.
Leather Master Products are used as a ‘benchmark’ by other leather care product vendors. All aqueous (water- based) cleaners will remove any body oil or salts, dirt and grime and wash them from the leather surface.
Today, Leather Masters™ leads the industry with over 350 different leather products. All Leather Masters™ products are manufactured in Montecchio Maggiore, Italy.
The world's largest tannery, located nearby, keeps them up to date on the latest changes within the industry. As an added bonus you’ll use a lesser amount of product with superior results.
The complex tanning process of chromed tanned hides results in the fat liquoring and oils necessary to keep the hide soft and pliable being locked in, this is further sealed by a durable polyethylene covering to protect the hide from abrasion from clothing as well as the dust / dirt introduced by the vehicle’s AC system
Surface Protection
It is essential as it will protect the surface finish (Leather Master™ - Protection Cream) 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 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.
Both Leather Masters Protection and Vital although water-based contain trace amounts of oil, which leaves only a very thin surface film to counteract surface abrasion by providing surface lubrication (driver or passenger entry / exit). (See also Oil and oil-based Products)
Ultra violet (UV) protection - 303® Aerospace Protectant will provide invaluable UV-B against photo degradation (fading) protection; especially in a roadster or convertible vehicle
If you have just purchased a new vehicle t will undoubtedly have finished leather upholstery I would strongly advise that you wipe down the surface with a damp cloth/sponge and apply a light coat of leather protection cream. This will help resist dirt, oils and stains and make future cleaning much easier.
This is particularly important if your leather is a light colour as this will help to resist and the removal of stains and dye transfer from clothing.
Usually, protected finished leather that have cracked or peeled is not from use, but from body oils and perspiration that have settled down into the grain of the leather and started to dissolve the finish over time. The Protection Cream will assist in preventing the cracking and peeling when proper cleaning is also done in combination.
Leather's greatest enemies are; dirt or grit abrasion, 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.
Upholstery leather given the proper care and protection will withstand all of the above; provided the loss by evaporation of its essential moisture is replenished to counteract drying and stiffening, and to maintain both flexibility and suppleness.
Wax and / or oils that are found in many conditioning products cannot permeate the finish but will only remain on the surface and attract dirt, which in turn will become an abrasive solution that will wear away the finish. They may also negatively affect the evaporation and hydration process. Water- based products do not contain oils and/or waxes so if the label says they do then don't use them.
Understanding dressings is essential; obtain accurate technical information on automotive care products can be problematic, but detailer’s should be knowledgeable on the dressings sold for leather (this is also true for tyres, rubber, vinyl, etc) and their chemical content. Otherwise they are at the mercy of the supplier to provide not only products, but also the technical knowledge and application methodology regarding product usage.
Unfortunately not all suppliers or distributors have the ability or technical knowledge to provide accurate information to the trade; some do not want to divulge what they term ’trade secrets’ as the information might be detrimental to their product sales or company image.
Honest opinion or merely advertising?
Commercialism brings with it concerns of honesty and true representation. In other words, it’s difficult to know what is true when someone is motivated by income
Hydration
When leather tanners talk about conditioning leather they are referring to re-hydration; not the replenishment or replacement of the fat liquoring oils and waxes. The only 'conditioning' required for finished leather upholstery is hydration.
Is simply the replenishment of lost moisture, water molecules are smaller than the ones used in the polyurethane top coats, so it can permeate the finish in vapour form. This is essential to restore the suppleness and maintain leathers natural flexibility and keeps the leather at its optimum physical performance level, along with softness and strength.
Leather is hygroscopic and so moisture is the most important element (median15 %) in the care of leather; all changes in leather are due to moisture differences. Too little moisture (< 10%) will cause the leather to become hard and inflexible, too much (> 20 %) and it may the fibres to swell and may cause mould formation.
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. 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
Moisture Content
Leather's major attribute is its ability to breathe, which it does even better than wool. This means not just its permeability to air but its permeability to water vapour, so allowing the absorption of perspiration and warmth. Thus it feels warm in winter and cool in summer, yet doesn't become hot and sticky.
On the other hand, whilst it absorbs water vapour it doesn't readily absorb liquid, so a light rain will not harm it and a damp cloth can be used to keep it clean
Leather naturally absorbs and retains moisture, meaning it’s also susceptible to losing the moisture necessary to keep it pliant and soft. The denaturing process of leather tanning removes moisture from the hide, introducing solvent-based products accelerates aging of the leather.
When leather tanners talk about conditioning leather they are referring to re-hydration; not the replenishment or replacement of the fat liquoring oils and waxes.
When leather tanners talk about conditioning leather they are referring to re-hydration; not the replenishment or replacement of the fat liquoring oils and waxes.
The only 'conditioning' required for finished leather upholstery is hydration;
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) As leather is porous, it loses its moisture through evaporation at a rate dependent upon two variables; ambient humidity level, and heat. Where ambient conditions are very hot and / or experience very low humidity, finished leather will lose its moisture, which must be replaced.
The breathability of leather allows small particles of moisture to move back and forth through the leather and this is what keeps it in good condition. Once the moisture levels in leather drop due to evaporation or transpiration it becomes dry and brittle, to avoid this it needs to be re-hydrated.
The recommended frequency for hydration is a function of the environment. For example, in an automobile, the head rests and top of the rear seat backrests tend to dry out very quickly due to direct, prolonged sun exposure.
Why does leather feel dry or stiff? What actually dries out is the leather’s moisture, which then leaves the fat liquors stiffer and less flexible (hence the feeling of dryness or stiff leather)
Surface moisture constitutes approximately 10% of finished leathers moisture content, which is subject to evaporation and must be replaced to avoid dehydration. Most of the actual hide’s moisture content is provided by the tanner when the fat liquor introduced during the re-tanning process, which maintains the moisture of the corium fibre matrix, allowing them to remain flexible. This fat liquoring is sealed into the hide and under normal circumstances should not require any maintenance
Aqueous (water- based) products restore the lost moisture of finished leather and maintain its natural flexibility. When moisture is replaced the fibres will become flexible again and gives the leather a softer feel. Being in an enclosed space with little to no ventilation will exacerbate dehydration if the leather is subjected to very high temperatures and low humidity conditions the fat liquor oils introduced during the re-tanning process may become destabilised, leading to the finished leather becoming dehydrated.
Apply an aqueous (water- based) product (Leather Master Soft Touch (ex Vital) this is not a conditioner per se but it will revitalise leather that has become dehydrated. It is also excellent for improving the tactile feel of leathers. Apply to surface and allowing it to remain, renewing as necessary. And then apply an aqueous (water- based) protection
Patina (softness)
Leather Master™ Soft Touch (ex Vital) - this is not a conditioner per se; it contains polymers in an aqueous emulsion and is used to improve and maintain the tactile feel and lustre by rehydration and to ensure the leather remains matte, soft and supple. It can also be used when doing repair work to help soften the area being worked on and to dilute some of the pigments, helping them to permeate
Apply a small amount to dry 100% cotton micro fibre towel, allow to dwell for 20-30 minutes and then wipe surface with a dry 100% cotton micro fibre towel. For revitalizing older leathers and also to improve the feel of stiff leathers it’s better to apply several thin layers than a heavy application
Allow the car to sit in the sun for one or two hours to warm the surfaces
Allow the car to sit in the sun for one or two hours to warm the surfaces
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.
Questions and/ or constructive comments are always appreciated
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