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Ear tags
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Small plastic labels attached
by one end to the ear of an animal indicating
ownership, origin, etc., and serving as an identifying
mark that enables producers to identify cattle
individually without the hide damage caused
by fire (iron) and freeze branding. Bar code-carrying
ear tags when used as ‘tracers’ may allow the
linkage of slaughter data with those of the
farm and promote hide improvement.
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Easy-care finish
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Type of finish which is particularly
resistant to oil, grease and soiling, wet and
dry rubbing and to solvents and detergents.
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Eco label
|
Labels for a product which fulfils
a set of requirements regarding the protection
of the environment.
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Eco product
|
Product which is recognised as
respecting some requirements regarding the protection
of the environment
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EDTA
|
See: Ethylene Diamine Tetra Acetic
Acid.
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Effluent
|
Generic term denoting wastewater.
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Effluent (untreated raw)
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Wastewater as it is generated
from the process without any treatment (clean
technology may be included).
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Effluent receiving sump
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Small tank for the collection
of wastewater before treatment. It is equipped
with pump to feed the effluent treatment plant.
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Effluent treatment plant
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Plant in which wastewater is
subjected to a process in order to remove polluting
substances.
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Egg albumen
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Commercial product in dried powder
form obtained from the white of chickens eggs
and used in binder preparations for glazed finishes.
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Egg yolk
|
Yolk of hens eggs, used in tawing
and fatliquoring on account of its content of
emulsifiers and lubricating oils.
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Elastic tissue
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Connective tissue of the kind
that occurs in the dermis and the walls of arteries,
chiefly elastic fibres composed mainly of elastin,
a protein similar to collagen and occurring
in networks or sheets in elastic tissue to which
it imparts elasticity.
See: Bate (v); bating.
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Elasticity
|
Property whereby
a material changes its shape and size under
the action of opposite forces but recovers its
original configuration when the forces are removed.
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Elasticity endurance
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Ability of a finish to resist
stretching, extending or deforming of the leather
without tearing, cracking or peeling off. To
test this ability, a lastometer or a tensometers
is used.
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Elastin
|
Very extensible and chemically
resistant yellow, fibrous protein,
occurring in certain vertebrate connective tissue
such as a fine
network in the reticular dermis (corium) layer
and round certain
arteries, and as a bundle in the nuchal ligament
(the thick elastic
ligament supporting the back of the skull).
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Electrified fence
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Barrier made of metal wire which
is insulated from, and fixed to, posts and through
which a high tension, low ampere intermittent
current is induced.
Electric fencing has been promoted
as an alternative to barbed wire for many years.
However, in spite of the concrete measures proposed
by the Confederation of Tanners and Dressers
of the European Community (cotance),
and the efforts of different national experts,
barbed wire injures continue to be among the
most serious cattle skin defects in the EC.
See: Scars; scar tissue
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Electrocoagulation
|
pr Electrochemical process used on some wastewaters
resulting in flocculation according to the process
of creating an electrical field between electrodes
which promotes the polarisation of anions and
cations in the effluent and the release of metallic
ions (Fe, Al) when the sacrificial anodes dissolve;
these ions generate hydroxides which enable
floc to form.
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Electroflotation
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Flotation in which bubbles (H2
or O2) are produced by electrolysis
of water using appropriate electrodes.
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Electron Capture Detector Gas Chromatography (GC-ECD)
|
Chromatography providing
for an extremely sensitive
gas chromatography detector (ECD = Electron
Capture Detector) at high specificity for chlorinated
compounds.
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Electronic nose
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Electronic early detector of
the odours of putrefaction with multiple electronic
sensors in place of human olfactory receptors.
The electronic nose mimics the human sense but
with greater selectivity, and detects some of
the initial breakdown products during putrefaction
early enough to prevent the decay and the high
financial losses generated.
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Electro-osmotic tanning
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Process proposed for accelerating
the vegetable tanning process by suspending
the hides in the liquor between two electrodes,
separated by permeable diaphragms.
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Electrophoresis
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Electrochemical process
in which colloidal particles, macromolecules
or molecules (deposited onto a solid support
like paper or collodium) with a net electric
charge migrate in a solution under the influence
of an electric current. Also known as cataphoresis.
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Electrostatic swelling
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Uptake of water by, and the swelling
of, a protein, attributed to alteration of the
electric charges through combination with hydrogen
or hydroxyl ions and consequently repulsion
of groups with similar charges.
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Elongation
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Amount of the increase
in a material’s length when submitted to a tension.
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Elongation at break
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Amount of the increase
in a material’s length when submitted to a tension
until its rupture.
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Eluate
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Solution resulting
from the extraction of a solid by a liquid or
from a chromatographic separation process.
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EMAS
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See: Environmental
Management Audit Scheme.
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Emboss (v); embossing
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Create a raised design upon a
leather by pressure from a heated engraved plate
or roller.
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Embossed leather
|
Leather embossed or printed with
a raised pattern either imitating or resembling
the grain pattern of some animal, or being quite
unrelated to a natural grain pattern.
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Embossing plate
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Heated engraved plate to emboss
leather
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Emergency stop (function)
|
Function which is intended to:
· prevent or reduce existing hazards to persons,
damage to machinery or to work in progress;
· initiated by a single human action when the
normal stopping function is inadequate for this
purpose.
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Emery
|
Hard metallic substance used
for buffing leather.
See: Buff (v); buffing.
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Emery wheel
|
A wheel dressed with, or made
of, emery or carborundum and used on the flesh
side of leather to cleanse it or give it a fine
nap.
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Emission
|
Emission of chemicals to the
atmosphere outside the plant or the workshop.
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EMS
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See: Environmental
Management System.
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Emulsify (v); emulsifying
|
Form an emulsion, dispersing
one liquid throughout another liquid in the
form of little drops.
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Emulsifying agent
|
Substance which enables one liquid
to be emulsified in another.
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Emulsifying power
|
Capability of a substance to
produce a stable emulsion of one liquid in another.
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Emulsion
|
Dispersion of two or more immiscible
liquids in which one is dispersed in droplets
throughout the other.
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Emulsion break
|
Separation, breaking of an emulsion
into its two phases.
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EN
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See: European
Norm.
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EN 45000
|
European Norm for
the certification of laboratories for testing.
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Enamel
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Uppermost layer of a hide or
skin exposed by the removal of the hair or wool
and epidermis. The enamel appears as a translucent
layer and gives the special properties of smoothness
and polish to the grain surface. Any damage
to this surface layer reveals the relatively
coarse underlying fibres.
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Endurance
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The ability of a leather to resist
surface damage, such as
cracking, when folded, grain outwards,
in two directions at right angles to give a
sharp corner. Flexing endurance may be tested
by a machine such as the Bally flexometer.
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Energy recovery
|
Recovery of energy from a process,
or from solid waste treatment.
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Environmental impact
|
Any modification to the environment,
positive or negative, which can be a partial
or total result of activities, products or services
of a body.
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Environmental Management Audit Scheme
(EMAS)
|
Voluntary scheme
for environmental accreditation of participating
enterprises that is audited by a competent external
verifier according to the requirements of EC
Regulation no. 1836/93.
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Environmental Management System (EMS)
|
System to achieve
environmental targets which is adopted by enterprises
and is certified by an accreditation body. The
system is based on the voluntary compliance
of the enterprises, according to the international
norm EN ISO 14000.
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Enzyme
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Natural catalyst, produced by,
and occurring in, living organisms and responsible
for bringing about certain chemical changes
necessary for their life; used in bating and
depilation.
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Enzyme unhairing
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Loosening of the attachment of
the hair or wool of a hide or skin by treatment
with an enzyme preparation.
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Enzyme-treated wool
|
Wool obtained by immersing woolled
skins, or pieces, in an enzyme solution to loosen
it.
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Epidermal
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Appertaining to the epidermis.
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Epidermis
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Outer non-sensitive and non-vascular
layer of the skin of a vertebrate that overlies
the dermis. The epidermis is made up of superimposed
layers, and whereas the principal constituent
of dermis is collagen, that of the epidermis
is keratin.
The two proteins are of very
different composition, and respond very differently
to treatment with unhairing solutions. When
skin is limed the epidermis is decomposed, thus
enabling removal of the hair, whereas the underlying
collagen is not adversely affected.
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Epithelial tissue (epithelium)
|
Tissue of the kind that covers
the surface of the body and lines some hollow
structures in humans and animals, consisting
of sheets of cells bound closely together without
intervening connective tissue.
Epithelium may be protective
(for instance skin), absorptive or secretory
(for instance glands). It may produce special
outgrowths (hairs, nails, horns etc.), and for
such purposes it may manufacture within itself
chemical material best suited for the
purpose (for instance keratin).
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Equalisation
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The mixing of effluents through
agitation or other means, in order to balance
variations in composition, pH, temperature and
density prior to subsequent treatment.
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Equalise (v); equalising
|
See: Level (v); levelling.
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Ester
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Chemical compounds of alcohols
and acids used as solvents or diluents in finish
formulations.
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Ether alcohol
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Chemical compounds of different
alcohols used as solvents in finishing formulations.
Note: (ethyl alcohol [ethanol]).
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Ether alcohol ester
|
Chemical compounds of different
alcohols and acetic acid used as solvents in
finishing formulations.
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Ethylene Diamine Tetra Acetic Acid (EDTA)
|
Ethylene Diamine Tetra Acetic
Acid (EDTA), or its water soluble di- (Na2EDTA)
or tetrasodium (Na4EDTA) salts, are
complexing agents that can combine by co-ordinate
bonding with a single metal atom to form a cyclic
structure called a chelation compound or simply
a chelate.
Chelating agents based on EDTA,
or its salts, provide a means of manipulation
and controlling metal ions that have undesirable properties
by converting them to stable complexes which
are not deleterious. The suppression of certain
properties of a metal without removing it from
the system or phase is called sequestration.
EDTA is a sequestrant, and the largest single
use of sequestration is the control of water
hardness (water softening).
Application in the tannery: water
softener, metal stains removal, dung removal,
stain prevention, inhibition of incrustations,
inhibition of proteolytic activity causing grain ‘enamel’ damage in modern low-salt
preservation methods; avoidance of red-heat
in storage.
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Eugenics
|
Eugenics, the science dealing
with factors that influence the hereditary qualities
of a race such as growth rate, body size at mature age, composition
of cows milk and ways of improving these qualities.
Note: The formation and improvement
of utility
breeds of the larger mammals based on
selection and planned matings.
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European Norm (EN)
|
Norm or method set
up and approved by a
European Committee and accepted by the
national Standards Bodies of the EU countries.
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Eutrophication
|
Enrichment of the water by nutritive
salts, particularly nitrogen and phosphorus
compounds, favouring algae growth.
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Evenness
|
Attribute of a dyed material
showing a regular, level and equal colour all
over its surface.
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Excess salt
|
Conventional - pack - salt curing
is an effective but relatively inefficient process
since more than 50% of the salt offered remains
as excess used salt.
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Exhaust air
|
Gas or steam produced during
leather manufacturing. Mainly used to describe
the exhausted air from finish application systems.
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Exhausted dye
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Total removal, more or less,
of a dye from a bath to the leather being treated.
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Exotic leather
|
Tanned and finished reptile or
batracian skin showing its original grain structure.
Note: Crocodile/alligator, snake,
etc.
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Extensibility
|
Capability of a material
to be stretched or distorted without breaking.
Also the amount of
extension at the breaking point.
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Extract
|
Liquid or solid obtained by leaching
a complex mixture with a solvent, such as water,
in which certain components are soluble and
others insoluble, and evaporating off the solvent.
Note: Concentrated aqueous extraction
products of the vegetable tanning materials.
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Extract tanning
|
Tanning process based solely
upon the use of tanning extracts, in contrast
to a process also utilising ground vegetable
tanning materials.
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Extractable fatty matter
|
Fatty matter capable of extraction
(in Soxhlet apparatus) from leather, by certain
organic solvents such as dicholoromethane.
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Extraction
|
Removal of polluted air by mechanical
or physical means. Local exhaust ventilation
should be designed to ensure that solvent fumes
(VOC’s) are drawn away from the point of origin
and do not enter the breathing zone of the operator.
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Extraction hood
|
Equipment under which the operator
works with toxic vapours. These vapours are
extracted through this equipment.
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