Help Needed Navigating Huge Debates Among Leather Care Professionals

Hello, everyone!

I've joined this forum because I'm eager to have someone set me straight. I'm ready to treat my precious handbags with some sort of leather care product, but my months of research online have revealed that no leather care professional seems to agree on what ingredients are safe and which are not. For every ingredient that can make it into a leather care product, I've read paragraphs about why it should be avoided. I'm beginning to conclude that everyone can probably be divided into at least two schools of thought. The first is those who embrace the use of animal oils. And the second is those who reject this idea and instead brace the use of petroleum derivatives, such as petrolatum. These two schools of thought seem to be at odds with one another, and I'm having trouble deciding myself! Would it be possible for someone to please set me straight? In addition, it would be amazing to have someone write and share a list of common leather care ingredients, with each ingredient's pro and con listed after it. Sorry for the tall order! I am SO excited to hear what responses I get! Thank you in advance!

Lisa

>>> I'm ready to treat my precious handbags

There are as many treatment types both for below surface into the leather structure and above surface.

And there are more than 30 types of Leather Problem Solving Matrix for reference to bring each leather tanning types and finishes type back to its originality.

You may just show us one of your bag and we can discuss pertaining to the problem at hand with the questions you posted.

Roger Koh
Leather Care System Formulator
Consultant / Practitioner / Instructor
web: www.leatherdoctor.com
forum: www.leathercleaningrestorationforum.com
email: [email protected]

Thank you, Roger!

I have several of two different kind of handbags. The first is made by Madewell.com. It is called "The Transport Tote" and I have it in several colors, but the one I am most eager to learn about is the one I have in the "English Saddle" color. Here is a direct link:

https://www.madewell.com/browse/sing...&bmUID=lpGC8rz

The second type of handbag of which I have several different colors is the Rebecca Minkoff Mini Mac. Here is a direct link:

http://www.rebeccaminkoff.com/mini-m...ky?src=catalog

Thank you so much for helping me out. Is the Leather Problem Solving Matrix you speak of available on this website? I would love to see it. I have seen a flow chart at Pecard.com.

Sincerely,
Lisa Goddard

There are as many treatment types both for below surface into the leather structure and above surface.

And there are more than 30 types of Leather Problem Solving Matrix for reference to bring each leather tanning types and finishes type back to its originality.

You may just show us one of your bag and we can discuss pertaining to the problem at hand with the questions you posted.

Roger Koh
Leather Care System Formulator
Consultant / Practitioner / Instructor
web: www.leatherdoctor.com
forum: www.leathercleaningrestorationforum.com
email: [email protected][/QUOTE]

These are the product information and pictures from the link for better direct viewing for our discussion.

Attachment 6897

>>> Product Details
What goes into our signature tote? Here it is by the numbers: 2 pieces of fine leather are used for the body. 8 inch strap drop: long enough to sling over your shoulder, but short enough to hold as a top handle. 1 interior side zip pocket to keep your keys, phone and wallet at the ready. 24: the number of hours in a day that this bag looks cool. How often you'll reach for it? 500 gazillion times.
• Made of vegetable-tanned leather that burnishes with wear into a beautiful patina.
• Please note: As it is made of a natural material, each bag varies slightly in texture and color.
• Interior zip pocket.
• Unlined.
• 8 1/4" handle drop.
• 14"H x 14"W x 6"D.
• Import.

>>> I'm beginning to conclude that everyone can probably be divided into at least two schools of thought. The first is those who embrace the use of animal oils. And the second is those who reject this idea and instead brace the use of petroleum derivatives, such as petrolatum. These two schools of thought seem to be at odds with one another, and I'm having trouble deciding myself!

We must ask ourselves what is the purpose of the animal oils or petroleum derivatives used for to treat your precious handbag.
The simple answer must be because leather sooner or later dries stiff and when flexed cracks and that is the end of the usefulness of leather when it looses its rip tensile strength. A well nourish leather with fat and oil up to average 15% content when dry will able to sustain a tear strength of 2000psi. When the fat and oil contents dries up the tear strength will decrease and below 1800psi signs of weakness will show on the needle holes that goes off round. The strength of the leather lies on its percentage of fatliquor content and fatliquor is the lifeblood of leathers. What ever you have mentioned about the animal oils and petroleum derivatives function is for lubricating the leather for flexibility. It is the fat content of the fatliquor that plumps the leather with fullness. Fat and oil is just like water and snow, fat and snow has more volume than oil and water. The leather will need both the fat and the oil, the oil for suppleness and the fat for aesthetic plumpness or fullness of appearance.

The next question is how the fat and oil works whether it is from animal, vegetable or mineral (petroleum derivatives). There are two versions how it will work, one is by stuffing and the other is by hydrogen bonding. Just like painting versus electro plating and surely the electroplating will be more lasting then just painting. The primitive softening of the leather is by stuffing the leather with fat and oil or sometimes brain to soften up the leather. Any stuffing fat and oil when easily stuff will also be easily leak out or evaporated and besides it’s mainly for utility than aesthetic and darkening effect does not matter. Modern tannery around the world today uses “fatliquor”. These ionic charged fatliquor are put into a heating rotating drum in warm water to create an emulsion to allow the ionic negative (-ve) charged fat and oil to hydrogen bond with the ionic positive (+ve) charged leather protein fiber. When the leather protein fibers is fully charged the water in the drum turns clear as the fat and oil is hydrogen-bond with the leather protein fiber. This is how your precious bag is initially treated for suppleness and fullness.

The advantages of leather treatment with hydrogen bonding besides the darkening effect, it allows the leather to breath for natural transpiration to take place. And remember the moisture fat and oil content when dry should average 14% - 16%. All vegetable-tanned leathers will need a higher content of fatliquor. This correct moisture content is measurable with a “leather moisture” meter or equivalent when the leather is fully dry.

And since fatliquor is an organic volatile compound (VOC) it will slowly evaporates just like our car engine and will require periodic topping-up.
As the leather dries the leather fibrils becomes closer and eventually becomes stick to one another resulting in stiffness and when flex cracks. Stiff or shrunk leathers has first to be relaxed and have the fibrils separated before the fatliquor can moves into its place and have the water encase molecules of fat and oil hydrogen bond with the ionic positive (+ve) leather protein fiber. When both fat and oil are hydrogen bond with the protein fibers the water contents about 5/6 will leave and open up the natural breathing spaces or pores. Fatliquor-5.0 is the fatliquor in a bottle ready to be used after the dried, stiff or shrunk leather is first preconditioned and ionic negative (-ve) charged with Hydrator-3.3. Thus the Hydrator-3.3 > Fatliquor-5.0 > Hydrator-3.3 non-immersion system works on a finished leather products such as you precious leather handbag, while the original sheets of leather works in submersion in a warm rotating drum with the same result.

Note that the product name suffix denotes its pH value, thus Hydrator-3.3 has a pH value of 3.3 and Fatliquor-5.0 has a pH value of 5.0. Most leather users are not aware that leather is an “amphoteric” material. Vegetable-tanned leathers like this bag mentioned is also more pH sensitive than other chrome-tanned and other mineral tanned leathers. Thus it is always prudent to note products pH value before it denatures the leather and revert it to raw hides when the leather constituents like the tanning-agent breaks the hydrogen bond and becomes tacky, dyestuff that bleeds or easily rubbed off and fatliquor that after drying becomes stiffer than before. Always used leather safe (pH 3 -5) products otherwise the extreme has to be pH balanced to its leather neutral (iso-electric point or pI).

So what is the logical choice based on science and logic - animal oils, petroleum derivatives or fatliquor?

Roger Koh
Leather Care System Formulator
Consultant / Practitioner / Instructor
web: www.leatherdoctor.com
forum: www.leathercleaningrestorationforum.com
email: [email protected]

Roger, wow, thank you for this detailed response! I had to read it 3 times carefully to make sure I understood it all. You certainly must have a chemistry background, and I do not! Haha. You have convinced me that fatliqours make sense, but then may I go further and ask you which product out there would be a good one to purchase and use? I am surprised that you recommended the product have a 3-5 pH range. I had previously thought that aiming for a neutral 7 pH was preferable. Do fatliquors have the potential to cause the leather to go rancid if too much is applied?

>>> I am surprised that you recommended the product have a 3 - 5 pH range.

When leather is read with a leather pH meter in the tannery it will reveal the pH value on a dry surface. It is mainly depending on the tanning agents, auxiliary including bactericide, fungicide, dyestuff and fatliquor as part of the leather constituents. Thus in most cases the Vegetable-Tanned leathers usually takes on a lower pH value that is why it is more pH sensitive. Another fact to know about leather is that the leather protein leather is an “amphoteric” material and any solution that is higher than the range of pH 3 – 5 will cause a shift of the ionic positive (+ve) leather protein fiber to weakens and shift to ionic negative (-ve). Remember that the leather constituents like the fatliquor and the others are ionic negative (-ve) charged. Ionic attraction behaves similarly like magnets with “like poles repels” and “unlike poles attracts”.


>>> I had previously thought that aiming for a neutral 7 pH was preferable.

pH is calculated by the power of 10. When a pH value of 7 is applied onto the leather, which has an average of 4. It will have a 3 points difference in ionic strength to the negative (-ve) for the protein fiber, while the other leather constituents are “non-amphoteric” will remain ionic negative (-ve) The 3 point difference calculate to the power of 10 becomes 1000 times off balance to the ionic negative (-ve) as well. Now can you see the damages slowly taken place as the ionic attraction weakens? Leather is pH sensitive as water is temperature sensitive and changes from ice, water to steam in the temperature range. Leather behaves similarly when put through the pH range it either strengthen the leather or weakens it denaturing to raw hide.


>>> Do fatliquors have the potential to cause the leather to go rancid if too much is applied?

The scent of the leather is much dependent on the quality of the fatliquor (ionic charged fat and oil), it should please any leather lover. Any awful smelly suppose “fatliquor” should not be used, so take a sniff of the bottle before you apply. Fatliquor is an emulsion same as fresh milk mainly with similar composition of fat, oil and water. In Fatliquor-5.0 it has 16.66% of ionic negative (-ve) charged fat and oil molecule encased in 83.33% of water content. With this composition as 83.33% of the content will evaporate that leave the breather pores open, it is unlikely to apply too much. When the leather is fully saturated with fat and oil it becomes less absorbent and you would know that it has reached it optimum level. An analogy is a wooden boat when put in water will soak up as much water as it can hold without allowing the water to come through. So a fully fatliquored leather will also resist the ingress of any unwanted water staining content especially from body oil, grease and sweat with constant body contact. Among the three content this unknown "sweat" is the worst culprit that eventually cracks the leather. You may want to know why then natural body oil, grease and sweat do damages to the leather as compared to your initial "Animal Oils and Petroleum Derivatives" as treatment?


Leather Approximate Quantity or Percentage of Fatliquor:
The quantities of fatliquor (fat and oil) contents retained in the leather after an universal tannery fatliquoring process may varies up from 14% to 16% depending on the leather types and it usage. This percentage drops as the fat and oil content diminishes or leaches through ageing, water, heat or chemical overexposure.
Leather rejuvenating or fatliquor replenishing is base on weight of the leather in relation to the percentage of remaining fatliquor. A simple calculation of percentage of fatliquor topping up requirement would be as follows:
If the weight of the leather in question is 100gm and fatliquor (fat and oil) content meter reading is less than 1%.
By applying 80gm of Fatliquor-5.0 to it will deliver an end result incremental of 13.3% fatliquor when dry as the 66.6% water contents evaporates.
In the leather rejuvenating Hydrator-3.3 > Fatliquor-5.0 > Hydrator-3.3 system, Hydrator-3.3 plays an important role by relaxing, opening up the inter-fibrillary spaces, facilitating and redistributing colloidal water movement, protonating and doing all the pre-conditioning work prior to fatliquoring including cleaning up any excess surface remnants to have a sticky-free surface. In practice with severe dryness the ratio for Hydrator-3.3 is 2 to 1 of Fatliquor-5.0.
It works out to be approximately 160gm of Hydrator-3.3 plus 80gm of Fatliquor-5.0 to replenish a 100gm dry leather from less than 1% back to the original tannery up from 14% to 16% fatliquor content.
In every bottle of Fatliquor-5.0 by weight content is comprises of 16.66% ionic negative (-ve) charged fat and oil, and 83.33% of water, the water content that encased the fat and oil molecule in an emulsion suspension when hydrogen bond with the ionic positive (+ve) leather protein fiber will break free and discharged from the leather structure to the surface.


>>> You have convinced me that fatliqours make sense, but then may I go further and ask you which product out there would be a good one to purchase and use?
You will need a Hydrator-3.3 > Fatliquor-5.0 Hydrator-3.3 combination system to work on fabricated leathers by non-emersion or emersion method.


Non-emersion application for obvious reasons
Attachment 6898


Emersion application where it applies:
The fat and oil content will be hydrogen bond [positive (+ve) and negative (-ve) ionic charged] with the leather protein fiber in the dwelling process leaving behind the discharged or exhausted water content clear in an enclosed condition for observation with the same principle as electroplating process.
Attachment 6899



Roger Koh
Leather Care System Formulator
Consultant / Practitioner / Instructor / Founder
web: www.leatherdoctor.com
forum: www.leathercleaningrestorationforum.com
email: [email protected]

>>> Do fatliquors have the potential to cause the leather to go rancid if too much is applied?

By looking at these pictures, do you consider that there is too much fatliquor going into the process?

Rancid is the contents that oxidized or gone bad before you even applying it.

It should be either odorless like fresh milk or a higher quality leather-scented before you apply it.


#1
Attachment 6900


#2
Attachment 6901


#3 This picture shows the fat and oil content was completely taken up by the leather and the clear water is the discharged as compared with picture #2 above.
Attachment 6902


#4
Attachment 6903


#5
Attachment 6904