Leather performances and business strategy:
The necessity of leather surface protectors for the industry and
consumers
Christophe Gaysse, TFL Leather Technology Ltd, Switzerland
The leather articles that are the most appreciated are often made of leathers which are the
most sensitive to soiling and staining during casual and professional use. In the case of
the footwear, apparel or furniture market, it typically includes nubuck and suede also
defined as vulnerable leathers.
Nowadays; industrial and consumers market reports are stating that stain protection is
seen as an area of growth in apparel and shoe. Because of the convenience and easycare concept it provides to consumers, surface protection, stain-protection and stainrelease as well as anti-soiling are the fastest growing concepts in technical development
and marketing.
A large range of protective performances
Due to a large surface area and fibrillar structure, vulnerable leathers readily absorb water
& oil based substances to which they can be frequently exposed. Thankfully, specialised
fluorocarbons can be spray or drum applied in order to provide protection to vulnerable
footwear.
Fluorocarbon treatments provide protection against the effects of wet weather, melting
snow, food or drink stains without changing the natural feel and look of leathers.
The protection imparted by fluorocarbons - whether by drum or spray application - treats
largely the surface-layers. Under heavy mechanical load it is possible for both water and
oils to penetrate this surface barrier. Under these conditions of stress it is therefore
possible to introduce stains. Nevertheless, if these leathers have been treated with
fluorocarbons they are much easier to clean than untreated leathers. Application of
fluorocarbons to washable leathers enables an “easy care” concept for footwear and
apparel.
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The 101 stains that ScotchgardTM can prevent!
Food & Drink
Olive oil
Lard
Coffee
Marmalade
Mayonnaise
Whisky
Red wine
Beer
Curry
Raspberries
Spinach
Burgers
Saffron
Candies
Grape juice
Eggs
Cherries
Gravy
Cheese Sauce
Yogurt
Maple syrup
Dairy cream
Baby food
Peanut oil
…
Corn oil
Sugar syrup
Tea
Soy sauce
Ketchup
Tomato sauce
Milk
Chocolate
Strawberries
Blueberries
Cola
Curcuma
Ice cream
Beetroot
Melon
Mustard
Salad dressing
Butter
Vinegar
Steak sauce
Chilli
Sorbet
Cakes
Jelly
Personal, healthcare & pets
Outdoor & at work
Lipstick
Blood
Urine
Antiperspirant
Hair dyes
Cough syrup
Mercurochrome
Mucous
Perfume
Body lotion
…
Motor oil
Alkalies
Acids
Salt solutions
Mineral solutions
Grease
Chemicals
Paints
Varnish
Ball point
Gasoline
Lubricating oil
…
Make-up
Vomit
Perspiration
Mascara
Vaseline
Suntan oil
Excrements
Baby formula
Iodine
Bath oils
Others
Shoe polish
Graphite
Soot
Ink
Dyes transfer
(migration)
…
Battery acid
Sludge
Dust
Soil
Grass
Tar
Rain
Sap
Slime
Clay
Pine resin
Car polish
Rust
Pollen
Household solutions
Glue
Keeps your leather looking good
longer!
Typical performances for surface protection of casual and industrial footwear
For casual footwear, there is a discernible increase in demand for improved comfort in
terms of longer-lasting coolness and dryness for the wearer of the shoe. In this respect,
leather has a natural advantage over synthetic footwear - as long as the leather is not
prevented from breathing by having been finished or heavily waterproofed. This is because
all finishes act as a surface barrier to the passage of water vapour, and likewise heavy
waterproofing reduces the water vapour permeability.
However, this demand for improved comfort cannot be separated from the consumer
expectation that footwear should also have some surface protection. Thankfully, the
protective materials from 3M (Scotchgard™ Protector for leather) impart surface protection
without any discernible effect on water vapour permeability, they are therefore, eminently
suitable for inclusion in recipes for making this type of shoe upper.
Fluorocarbons also offer a high level of protection in industrial applications. This is
especially important in areas where leather might otherwise be subject to breakdown of
the structure, such as contamination by acids or alkali.
Salt stain resistance.
Walking in winter time on a snowy street can easily turn into a disaster when a couple of
hours later, after drying, a white crust of salt appears, creating an irreversible loss of
softness and an unpleasant aspect to the shoes, especially on dark shades. The
fluorocarbon barrier protects the leather from salt water, even if the salt can dry out on the
leather surface, a very smooth brush will be enough to get rid of the stain.
a
b
c
Salt stain resistance :
a) Treated and non treated shoes are plunged into saturated sodium chloride solution for 1 hour.
b) The shoes are air dried and cleaned with regular shoe brush.
c)
Treated shoes keep its original quality. Salts stain remains on the non-treated shoe via crystallization
inside the leather structures creating an irreversible lost of softness and unpleasant aspect to the
shoes.
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Industrial risks for footwear and gloving
Industrial footwear and gloving also requires a best in class surface protection. Handling
strong acids and alkalis at work means a complete and safe protection for the workers. A
fluorocarbon treatment with 3M Protective Materials builds an outstanding surface
protection against the most concentrated acids and alkalis. Hydrochloric acid even does
not alter the leather surface but without any treatment, the leather would dramatically and
instantly shrink. Also a boiling saturated solution of sodium hydroxide will only cause a
slight burn of the leather surface instead of complete through penetration without a
fluorocarbon treatment.
a
b
Acid resistance :
a) Spontaneous reaction of hydrochloric acid on non treated leather
b) Demonstration of acid resistance of treated leather
The peace of mind of the customer!
Wearing a suede or double face coat in the rain or sitting on a smooth comfortable nubuck
sofa requires trust in the protection of your most valuable goods.
Increasing numbers of companies have understood the necessity of easy maintenance”
and “easy care” to promote their products at the consumer level. What is better than
wonderful apparel, machine-washable with lasting protection against stains?
Nowadays “peace of mind” concepts become more & more important and respected
buying factors by the end user.
Application of 3M Protective Materials Protector for leather
1) When applied in the drum at tanneries, the following recommendations are typical
levels of application. These levels shall qualify for the brand Scotchgard Protector for
Leather
•
As a co-application:
After the dyeing process, 3-6% PM 4700 (on shaved weight), 10 min prior or after
the introduction of the fatliquors.
•
As an after treatment in the drum:
3-6% PM 4700 (on shaved weight), in a fresh bath, 35-50°C; pH 3.5-3.7; 40-60 min.
2) When used as a spray application to the grain or suede surface, the following are
typical levels of application:
•
Aqueous spray application
75-300g PM 4701
925-700g Water
Apply 15 – 5 g/ft2 (co-solvents for wetting - ethylene glycol or methoxypropanol)
•
Solvent spray application
25 - 50g PM 4800
975-950g solvent or solvent blend (ethers, ketones & esters).
Apply 15 - 5 g/ft2
Keep your leathers looking good longer…
The surface protection of treated leathers kept under static conditions actually continues to
improve for some months. The effect of wear can however, have the opposite effect and
this can be simulated by a simple abrasion test which is based on the use of sandpaper
attached to the head of a crock meter. There is little change in the performance of 3M
Protective Materials products by this surface abrasion, whereas products available from
other sources show a lowering of performance.
The performance monitoring for the Scotchgard branding procedure includes oily and
watery repellency before and after such abrasion. This establishes the Scotchgard™
Protector for leather as the best in class surface treatment with durable performances.
As a consequence, production of nubuck and suede via direct process is conceivable,
reducing the long and expensive standard process via crust.
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New chemistry and favourable environmental profile
The 3M fluorochemicals used in the treatment of leather are based on perfluorobutyl
chemistry. When applied, dried or cured onto the leather fibres, the fluorochemicals tails
orientate themselves away from the substrate conferring to the leather surface a low
surface tension, allowing liquids to bead up and repel.
In the 1990's, it was found that the ultimate breakdown product ( PFOS Perfluorooctanesulfonate ) of the perfluorooctanyl ( C8F17- ) based chemistry, which was
used at that moment in surface protectors, was being found in the environment, at very low
levels. Although extensive research indicates that no health or environmental effects result
from these breakdown products at these very low levels, it was decided by 3M to phase
out these products.
After significant R & D work, new leather protectors based on perfluorobutyl chemistry (
C4F9-) have been developed. This new technology has a favourable environmental, health
and safety profile. With the help of these new building blocks it is possible to produce high
molecular weight polymers that remain stable during the useful lifetime of the treated
leather. Furthermore the polymers are developed in such a way that they will contain very
low levels of residual monomers that have the potential to degrade further to PFBS (
Perfluorobutanesulfonate).
Concerning the ultimate degradation product of this new chemistry, PFBS, test findings
provide evidence that this substance is persistent, but it is not considered bioaccumulative
or Toxic under the U.S. EPA persistent, bioaccumulative, and toxic chemical policy. The
acute ecotoxicity data show that PFBS would be classified as an insignificant hazard by
the U.S. NIOSH and require no label warning by the E.U. regulations.
The necessity of branding for leather
Scotchgard™ Protector for leather is one the most famous brands applied in the leather
industry. The high recognition level and reliability of Scotchgard™ Protector for leather and
related performances are determining advantages for business opportunities. Brand
differentiation is nowadays an outstanding solution for gaining new market shares.
Scotchgard™ Protector for leather and its dual action which offers stain repellency and
stain release is the key solution in combining the appropriate leather treatments to match
consumer’s expectations.
To apply the Scotchgard™ brand to shoes, apparel or furniture; leathers must pass
stringent specifications regulated by 3M procedures involving the most rigorous methods
for leather surface protection assessment.
Distribution of Scotchgard™ Protector for leather
TFL is the authorized distributor of 3M protective materials for the leather industry. PM
4700 is an aqueous based product for drum application, PM 4701 is an aqueous based
product for spray application and PM 4800 is a solvent based formulation for spray
application.
Keywords
Vulnerable leathers; footwear, apparel, furniture, gloving, fluorocarbons treatment; oil,
water and stain repellency; keeps your leather looking good longer; favourable
environmental profile; branding; determining advantages for business. ScotchgardTM
Protector for Leather
Acknowledgments
Special thanks to Dirk Coppens, Pierre Vander Elst, Hans Ulrich Schenk from 3M, Victor
Callegher and Mike Donohue from TFL for their contribution to this article.
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