| Sl. No. |
Description of item |
Manufacturing Norms Conditions. |
| 1 |
2 |
3 |
| I |
Leathers with finishing coat (All substrates –
Goat and Sheep skins and Bovine hides/sides calf skins including splits) |
- Tanning
- Dyeing (optional)
- Fatliquoring
- Finishing coat
|
| II |
Suede Leathers (All substrates including splits) |
- Tanning
- Dyeing in light/pastel/medium/dark shades
(in case of doubt, the presence of dye to be ascertained by
chromatographic technique)
- Fatliquoring
- Buffing to produce suede nap
- Shaving/snuffing of the grain along the
backbone 2 inches on either side in the case of goat and sheep skins
and in the case of bovine hides/sides
and calf skins all over the grain side
|
| III |
Nubuck Leathers (All substrates including butts and
bends) |
- Tanning
- Dyeing in light/pastel/medium/dark shades
(in case of doubt, the
presence of dye to be ascertained by chromatographic technique)
- Fatliquoring
- Buffing on the grain to produce nap with writing
effect (or) Buffing on the grain and presence of oil in the case of
oil nubuck leather
|
| IV |
Bovine hides/sides based Lining Leathers: |
Thickness less than or equal to 1.0 mm
- Tanning
- Dyeing in light/pastel/medium/dark shades (in
the case of doubt, the presence of dye to be ascertained by
chromatographic technique
- Fatliquoring
|
| V |
Gloving leathers (All substrates): |
Thickness should be less than or equal to 1.0 mm and run should be
minimum of 15%
- Tanning
- Dyeing (optional)
- Fatliquoring
- Wax coat
|
| VI |
Burnishable Leathers (All substrates including butts
and bends) |
- Tanning
- Dyeing in light/pastel/medium/dark shades (in
case of doubt, the presence of dye to be ascertained by
chromatographic technique)
- Fatliquoring
- Wax coat
- Burnishable effect on rubbing (Minimum CIE
∆L value of –5.0 on 10 dry rubbing on SATRA Fastness tester or any
other fastness tester as measured on a Reflectance
spectrophotometer)
|
| VII |
Pull Up Leather – Wax/Oil (All substrates including
butts and bends) |
- Tanning
- Dyeing in light/pastel/medium/dark
shades(in case of doubt, the presence of dye to be ascertained by
chromatographic technique)
- Fatliquoring
- Wax coat (or) Oil coat
- Pull up effect (Minimum CIE ∆L value of
+5.0 as measured on a reflectance spectrophotometer)
|
| VIII |
Heavy Leathers including sole leather, harness and
belting leathers (Bovine hides/sides including butts and bends) |
Heavy substance with thickness of 3.0 mm or more and with minimum of
apparent density 0.9 gm/cc)
- Vegetable Tanning
- Oiling/stuffing
- Rolling / Plating
|
| IX |
Hair/wool on leathers (All substrates including
rabbit skins) |
- Tanning
- Dyeing(optional)
- Fatliquoring
- Wool/hair combing
|
| X |
Laminated Leathers (All substrates including splits) |
- Tanning
- Dyeing(optional)
- Fatliquoring
- Application of foil/film/lamination
|
| XI |
Chamois Leathers (All substrates) |
- Aldehyde and fish oil combination tanning
- Buffing to produce suede nap
- Complete shaving/snuffing of the grain
|
| XII |
Shrunken Grain/Washed leathers (All substrates). |
Should have pronounced change in the grain pattern/texture of grain
- Tanning
- Dyeing (in the case of doubt, the presence
of dye to be ascertained by chromatographic technique
- Fatliquoring
- Wax coat
|
| XIII |
Wax/Oil coated leathers |
- Tanning
- Dyeing in medium/dark shades
- Fatliquoring
- Wax coat (or) Oil Coat
|
NOTE: Any new type of finished leather not covered under the above categories
shall be permitted for export, subject to testing and certification by Central
Leather Research Institute (CLRI)
Definitions of manufacturing operations
Tanning – Tanning with one or more than one kind of tanning agent,
such as mineral tanning and vegetable tanning and / or syntan tanning and/ or
resin tanning and/or aldehyde tanning, oil tanning in any sequence and or any
new type of tanning.
Dyeing – Treating the leather with a solution of dye/s to impart a colour . In
case of doubt the presence of dye should be ascertained by extracting dye from
leather using suitable solvent mixture and by running thin layer chromatography
(TLC)
Note: 1:- Testing for the presence of dye:
Organic layer separated from Butanol, acetic acid and water mixture taken in the
ratio 4: 1: 5, using a separating funnel is taken as the eluting solvent for TLC
analysis.
Dye is extracted from the leather using dichloromethane and methanol (1: 1)
mixture. The cut pieces of leathers are heated in a water bath with the solvent
mixture for few miniutes.The extracted dye is kept as a spot on the TLC paper
and the strip is kept in the eluting solvent such that the dye spot lies above
the solvent level. The presence of the dye is confirmed by its movement to a
considerable distance and from the formation of a dye curve or peak on the TLC
paper.
Fatliquoring – Treating the leather with oil and/or fat, emulsified in water for
rendering the leather soft
Finishing Coat – Finishing coat shall contain a film forming material/ binder in
combination with colorants such as pigments or dyes or a combination of both.
The film forming material/binder shall comprise materials singly or in
combination such as proteins or synthetic acrylic or polyurethane, vinyls
lacquers or lacquer emulsions.
If necessary, microscopic examination of the surface at minimum 100 times
magnification shall be carried out to detect the finishing coat.
Note 2: - Microscopic examination for finish coat:
Binocular stereoscopic microscope with (two paired) objectives capable of
viewing the objects at a total magnification of 100X will be required.
Stereoscopic microscope gives a three dimensional view of the object.
Leather sample to be examined is placed on the stage of the microscope with the
grain facing the objectives and then the surface is focused. Two or three places
in each of the five locations namely butt, belly (one each side of the back bone
line) and neck or shoulder examined.
To the naked eye, the grain surface may appear to be plain, but when focused
under microscope, innumerable depressions can be seen on the surface. These
depressions are due to cleavages lines and hair pores. If finish coat is sprayed
on the grain surface, it will be present throughout, including depressed areas
and both the depressed and other areas will produce the same type of reflection
which is clearly visible under the microscope.
Buffing – An operation to produce a clean flesh surface to produce nap on
leather by the action of emery wheel or a buffing machine
Shaving – A mechanical operation of reducing the substance of leather to uniform
thickness by scrapping off layers from flesh or grain side
Snuffing – The process of buffing the grain side of leather usually done by
buffing machine, with visible evidence of removal of grain
Oiling – The operation of rubbing oil on the grain side of wet or sammed
leather with the object of making the leather soft and pliable; in the case of
vegetable tanned leather also to protect the color of tannage from darkening by
oxidation.
Wax coat – Wax particulate matter should be seen under Microscope (100x) after
the application of xylene on the grain surface.
Note 3:-Microscopic examination of wax coat:
A small drop of xylene is placed on the surface of the leather. The surface is
scrapped gently using a glass rod. Leather is left for 2-3 minutes. The dried
leather surface is observed under microscope for the presence of wax crystals on
the surface.
Burnishable Effect – Rubbing on grain surface of leather should show a distinct
gloss with a darkening of the shade giving rise to a burnishing effect. Minimum
CIE ∆L value of – 5.0 on 10 dry rubbing on SATRA or any other fastness tester
Pull up Effect – Leather shall produce a distinct pull-up effect showing a
contrast light color from the base minimum CIE ∆L value of +5 as measured by the
reflectance spectrophotometer.
Wool Combing– The operation through which wool entanglements are
released.
Application of foil/film – Acrylic/ PVC/PU foil or film
Rolling – The operation of rolling the heavy leathers like sole leather using a
heavy roller with rolling machine.