Thanks to Detailingwiki


Automotive Leather Upholstery Care / Maintenance
Leather used in Automobiles:

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). In accordance with US government standards theses should be labelled as 'split leather', although they are being sold by many automobile manufacturers as ‘premium leather’. Some of these ‘split leathers’ are covered with a vinyl or urethane coating.

Leather is the most delicate and difficult to maintain of any vehicle surface. It ages and wears faster than surrounding materials which can depreciate the vehicle's re-sale value. Before using a leather care product, a detailer needs to know the material they are working on, and whether the product chosen is compatible with the material and will not damage it. Diagnosis is the key, not guess work. Before deciding on what products to use, you need to ascertain what type of leather finish you have and whether the pigmented leather has a polyurethane covering, or is un-coated, finished natural leather. This is critical, as the cleaning / maintenance varies for each type (although all types require a water-based product to maintain hydration - a suede type leather like Nubuck is the exception).

Automotive leather care is a subject surrounded with misinformation and myth. Products such as leather (Saddle) soaps, oil-based Conditioners, Neats-foot oil, and Hide Food still prevail as top sellers, albeit most are made for equestrian tack. Leatherique, an oil-based product, is also a very popular product that is used in a market that is dominated by pigmented leather with an acrylic water-based polythene protective covering. These are very different leathers with drastically differing care requirements. The exact reason for this type of misapplication is unclear. It’s possible that there is an association with old world quality (i.e. European automobiles with leather upholstery and real burl wood interiors) with these types of products, despite the fact that the automotive industry has been using water-based polyurethane covered pigmented leather for many years.

How your leather feels (its Patina – literally ‘hand’) tells you more about its condition than anything; it should feel like something between velvet and satin. Supple, inviting and luxurious. Leather care starts with maintaining factory fresh feeling leather from the beginning. Keeping it clean is important, and hydration is the key; preserving the life, flexibility, appearance and longevity of your leather.

All cowhides are naturally oily, unfortunately, these natural oils are stripped away in the tanning process (tanning is a process using a water vat and chromium salts to preserve hides and prepare them to absorb dyes) and some equivalent oils must be re-introduced after tanning (See fat liquoring). These fat liquoring formulas are closely held secrets, passed down through generations; this is the origin of the new car ‘leather smell’. This is one reason why one company's leather can have a totally different feel, fragrance, texture and softness from another company's product. Modern leather tanning methods; chrome tanning, seals the hides ‘locking in’ the necessary fats and oils. It is then pigmented, by spraying a coloured polymer resin to the hide to provide uniform finish. Leather is hygroscopic (it naturally absorbs and retains water), meaning it’s also susceptible to losing the moisture necessary to keep it pliant and soft. All that is required is re-hydration of the leather hide to avoid it drying out.

Depending on the desired product, the hides then go through a water-based dyeing process, which also involves adding moisture back into the skin. Automotive leather is then pigmented with a water-based colour and finished. Most leather then has a water-based polyurethane protective coating applied. Since the denaturing process of leather tanning removes moisture from the hide, introducing water-based products restores the lost moisture of the hide to maintain its natural flexibility.

Protective coatings are applied by spraying water-based acrylic polyurethane, which is porous, so it does not completely seal leather, per se. It’s also thermoplastic and therefore remains pliable to follow the flexing of the leather upholstery. The coating is less than 1-millionth of an inch thick, and is water permeable, thus allowing the leather hide to breathe and to allow hydration. Under normal conditions, the polyvinyl coating and the split leather hide will last the lifetime of the vehicle, but only if proper care is provided. Hydration is important to ensure that the leather hide does not dry out as this would make the leather more likely to absorb stains / spillages; as once these are absorbed they can be almost impossible to remove.

Leather is a natural product and its surface contains pores, this helps the leather to hydrate. If looked at under a microscope it will show an uneven surface and when leather becomes soiled, the soiling embeds itself into the 'valleys' of the leather. Gentle agitation is what is required for cleaning. By using a great deal of force on the leather surface, you will only abrade and push the dirt deeper into the surface.

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 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 polyurethane 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.

Water-based products are able to permeate deep into the hide, which is essential for suppleness recovery. Upholstery leather should be routinely cleaned with a pH balanced, non-alkaline cleaner to loosen and lift grease, dirt and dust without overly drying the leather or affecting the hide’s natural pH. In addition to regular cleaning to remove abrasive debris and oils, leather requires regular replacement of its moisture (re-hydration)

Choose a product that does not clog the pores of perforated leather and does not contain harsh chemicals that can damage the protective covering or strip the pigmented dye. The overall objective is to maintain the appearance of the leather as it was from the factory.

Prevention is far better than correction. Leather that has become cracked from inadequate hydration or inappropriate care usually cannot be restored to its original state by most available products / methods. It is highly recommended that you fully clean, hydrate and protect auto interiors leather upholstery surfaces 3-4 times per year (dependent upon climatic conditions. It is much easier to practice prevention than it is to correct major problems after the fact

 

The rest at there website

http://detailingwiki.com/index.php5?...e_Leather_Care

 

I'm glad the information was informative