How to Avoid Leather Care Side Effects!
1] Process of Leather Making:
Leathers unlike most other materials found in modern cars, furnishings, garments and bags is not made by an instant push of a button; but is first grown in the fields; follows by an average of 11 wet and 8 dry operations in the tannery, involving proper pH dovetailing of many chemicals ranges from, pH 1 to 2 during the pickling process and pH 12 to 13 during the liming process, besides the numerous mechanical operations; before they are ready to be made into luxury leather items and seats associates with today’s modern luxury cars; fascinating and appealing to both man and woman alike.
Video explaining the making of Vegetable-Tanned Leathers - Hermann Oak Leather Tannery Tour http://www.youtube.com/watch?v=XyCaonpEd70
2] Chemistry of Leather Making:
The chemistry that goes into the converting of perishable protein hides to non-perishable leathers is what matters most to us; as incompatible after care products used with oblivious side-effects may snowball into stiffness and cracks. These three main pH sensitive leather constituents are the tanning agent, dyestuff and fatliquor; suppleness of leather depends on the fatliquor, the life-blood of leather, keeping the leather soft and strong. All aftermarket rejuvenators or conditioners purpose is to try replenishing it, as it slowly diminishes as VOC (volatile organic compound); accelerated by heat, solvency and alkalinity.
Video explaining Fatliquoring - http://videos.howstuffworks.com/disc...quor-video.htm
3] Hydrogen-Bond:
These anionic negative (-) leather constituents are hydrogen-bond with the cationic positive (+) leather protein fibrils and they are especially sensitive to temperature and pH value. When their ionic bonds are pH disrupted, it repels one another like magnets; thus, the exposed tanning agent areas become sticky or slimy when wet; the exposed fatliquor areas becomes stiff; and rings will result from aniline leathers known to the Ford King Ranch.
Video explaining Hydrogen Bond - http://www.youtube.com/watch?v=lkl5c...eature=related
4] Isoelectric Point:
Mild acidic products ranges from pH 3 to 6.9 are recommended for safe general cleaning of leathers. When unsafe alkaline products ranges from 7.1 to 11 are used, without immediate corresponding neutralizing and seeped through leather finishes into the absorbent leather structure through finish worn areas, perforated panels and weak construction needle holes and seam edges, it will cause the protein fibers to shift anionic negative (-); thus repels the other negative (-) leather constituents as well; that leads to the accelerated denaturing of the leather, manifest as stiffness and cracks.
Video explaining Isoelectric Point – http://www.youtube.com/watch?v=Fkv89VW8g38
5] Leather-Safe System:
A leather-safe system will ensure that when inevitable alkaline product is used for specific purpose, it is neutralized to return the leather to its pH neutral of 3 to 5; that the chemistry integrity of the leather is not compromised. The level and type of soiling is matched with appropriate calibrated strength of cleaning solution according to Leather-Safe Problem Solving Guides, not under cleaning it nor over cleaning it; with adopted leather cleaning principles based on tannery practices worldwide. Thus a technician who have gone through a Leather-Safe Course will be certified as a Leather-Safe Certified Technician and a firm hiring these technicians will be approved as a Leather-Safe Certified Firm.
6] Leather Desired Softness and Suppleness:
Leather when is wet and dry again, its fibers tends to stick together that makes the leather stiffer than before it was wet; thus it is recommended that they are fatliquored while it’s still damp prior to drying it. In so doing the fibrils are lubricated so that when the leather is dry, these millions of fibrils behaving like connecting hinges will slide over one another smoothly; thus a soft and supple leather at all times.
So far we have been dealing with the leather structure, where non leather-safe care products, may destabilize the chemistry composition of the leather structure, which results in premature ageing. Now we are going into the leather finish that comprises of two micron layers the colorcoat and the topcoat.
7] Leather Finish Types:
The finish of leather determine its finish types and the majority of leather seats are pigmented; which include the pigmented non-absorbent, micro-pigment semi-absorbent and the napa-pigmented absorbent; these are also referred to as the coated leathers. Aniline leathers found in Ford King Ranch is aniline dyed with a gloss topcoat. The reverse side of smooth leather is also used as suede trim in some models; so products safe for suede should also be safe for its smooth leather side and vice versa.
8] Pigment Color Coating:
Auto pigment is UV stronger than the typical indoor furnishing pigment type. The opaque color coating we see is a film ratio averaging 1 part pigment to 2 part binder in various formulations; with an average micron thickness of 0.02mm. This pigment color coating is essentially for the fashion aesthetic appeal.
9] Micro-Crazing Phenomenal:
Some pigment coating films in micro and napa pigment leathers are acceptably soft due to micro-crazing phenomena that allow the leather structure to breathe through these cracks in a discontinuous film, commonly refer to as transpiration of leather for seating comfort. Thus non leather-safe cleaning solution may further wedge the micro-crazing and developed into macro cracks and allowing it to seep into the leather structure that result in stiffness and cracking to the leather structure.
10] Plasticizers:
In order for the color coating to be compatible with the leather structure in terms of compressibility, stretchability and flexibility “plasticizers” is incorporated; to achieve a continuous film commonly refer to as coated or protected leather; where a water drop test pools on the surface. Plasticizers do migrates and evaporates as VOC sooner in adverse non leather-safe cleaning products result in premature brittleness to the film coating.
11] Topcoating:
The objective of the topcoat is to impart a film forming coating that provides abrasion and stain resistance to the colorcoat. It is this topcoating that decides its desired luster of glossy, satin or matte. Without this topcoat, the color basecoat would be: a) poor in aesthetics such as appearance and feel; b) susceptible to sticking together or attracting loose dust and dye especially in hot humid climate region; c) poor physical properties such as wet rub, sweat resistant and scuff resistant; d) poor in ageing properties such as soil resistant and wet cleaning resistant.
12] Non-Stick Rub-Resistant Protection:
This topcoat is subject to wear and tear as leather seat is design to be seat on; thus prolonging the durability of this topcoat is what aftermarket conditioners and protectors are after. The recommended protection should be: a) non film forming that allows leather transpiration for more seating comfort; b) non-stick to shield the detrimental effect of sticky soiling; c) resistant to wet and dry rubs, thus reduce stretch, scuff or abrasion; d) reduce friction squeaks when leather is rubbed or wear during the moving in and out or cars; e) modify the tactile-feel of choice between buttery, draggy, silky or waxy; f) impart a classic leather scent that charms, making leather more appealing to our senses.
13] Side Effects:
What is immediately visible is the streaks and brightness when non leather-safe alkaline products are used. The surface becomes slimy when wet and tacky when dry. If it affects the finish coating, it will be more damaging to the leather structure our eyes and fingers cannot detect, and the first noticeable side effect will manifest as stiffness of the leather.
Points to Ponder when one may think that it is OK to use non leather-safe products on new coated leathers:
14] Beauty, Comfort and Weakness in Perforated Panels:
Perforated leather seats are gaining popularity in most luxury modern cars. These are supposing coated leathers that are punch through for greater degree of transpiration, besides for the added aesthetic beauty; thus highly absorbent in these perforations. Products cautions against the use on suede will have a damaging effect to the leather structure at the molecular level our eyes cannot see, that will eventually manifest as premature stiffness and cracks.
15] Weakness in leather seat construction:
Needle holes and seam edges in every panel are not protected as you would expect on the surface areas. This construction weakness is where not for suede or non leather-safe products start the early denaturing of the leather with stiffness and resulting in cracks.
What do you think?
Roger Koh
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