|
C.I.E.
|
Commission Internationale d’Eclaraige
(= I.C.I. International Committee of Illumination). This Commission
defined some standard illuminants, and observers.
|
|
C.I.E. triangle (thrichromatic diagram)
|
C.I.E. trichromatic components,
which represent the sensitivity of the eye to red, green and
blue and defined the colorimetric reference observer.
|
|
C.I.E.L.A.B. co-ordinates system
|
CIELAB colour space is a system
to represent the tristimulus values in which there is a plane
(A-B) with the bright colours and a perpendicular axis (L) on
which white-black is represented.
|
|
Calfskin
|
Skin from a young bovine animal
not exceeding a certain weight, which varies from country to
country.
|
|
Canaigre
|
Plant growing in Mexico and California,
whose tuberous roots contain 18% to 43% tannin.
Note: Rumex hymenosepalus.
|
|
CAP
|
See: Common Agricultural Policy.
|
|
Cape leather
|
Originally a soft, grain gloving
or clothing leather made from South African hair sheepskin;
now any similar leather made from hair sheepskin, but not finished
leather made from East Indian
native vegetable tanned hair sheepskin.
|
|
Carbon dioxide
|
A heavy, colourless, odourless
gas, present in the atmosphere or formed by the burning of fuels.
Carbon dioxide is also exhaled by animals and used by plants
in photosynthesis. It is also produced during biomethanation.
|
|
Carbon dioxide deliming
|
Deliming by means of carbon dioxide.
|
|
Carcinogen
|
Substance or preparation which,
by inhalation, ingestion or skin penetration is believed to
cause cancer in humans.
|
|
Carding leather
|
Butt leather, vegetable (originally,
oak bark) tanned, lightly curried and fairly flexible, for holding
the steel wires that form the periphery of the cylinders on
the carding machines used in the woollen industry.
|
|
Carpincho
|
Grain gloving leather with a
grain pattern somewhat like that of peccary, made from the skin
of a water rodent indigenous to Argentina, Uruguay and Brazil.
Note: One of the leathers commonly
designated as Hogskin.
|
|
Cascalote
|
Pods of a tree found in Mexico.
Note: Caesalpina cacolaco.
|
|
Case hardening
|
Outer
surfaces of the hide or skin are tanned too rapidly thus preventing
the tan liquor reaching the interior of the skin. Excessive
build up of tanning agent on the surface leads to hardening
and even eventual cracking of the grain.
|
|
Casein
|
Protein obtained from skimmed
milk by precipitation with hydrochloric acid and used in finishes.
Dried casein is available in a great number of commercial products
having different viscosities depending on their application
and composition.
|
|
Catechin tannin
|
Strictly speaking a tannin somehow
formed from a catechin
(5 : 7 : 3’ : 4’ tetrahydroxyflavan – 3 – ol) unit ( gambier),
but also sometimes applied to tannins formed from related units,
such as a trihydroxyflavan-3-ol (quebracho) or a trihydroxyflavan-3-4-diol
(mimosa).
|
|
Catechol tannin
|
Tannin presumed to contain a
catechol nucleus because it gives a green colour with a ferric
salt or yields fragments with a catechol nucleus on alkaline
fusion.
|
|
Cationic dyestuff
|
Ion, molecule or radical from
a dyestuff with a positive charge.
|
|
Cationic fatliquor
|
Ion, molecule or radical from
a fatliquor (oil globules) with a positive charge.
|
|
Cationic resin
|
Ion, molecule or radical from
a resin (organic substance) with a positive charge.
|
|
Cationic soap
|
Ion, molecule or radical from
a cleansing substance with a positive charge.
|
|
Cationic surfactant
|
Ion, molecule or radical from
a surfactant with a positive charge.
|
|
Cauliflower effect
|
Loss of
substance during wet processing due to vertical fibre effect,
leads to a “cauliflower” like pattern on the flesh side.
See: Vertical fibre.
|
|
Cellulose aceto butyrate lacquer
|
Film-forming product in finishes,
abbreviated CAB. Good stability to yellowing on exposure to
light and heat. Excellent fastness to migration and resistance
to free amines of polyurethane foams.
|
|
Centrifugation
|
Partially separating sludge contained
in water by means of centrifugal force.
|
|
CFC
|
See: Chloro Fluorocarbon.
|
|
Chain
|
Chain of molecules
bound to each other to form a new chain. For example, a chain
of amino acids to form a protein or a chain of monomers to form
a polymer.
|
|
Chamois
|
Leather made from the flesh of
sheep or lambskin, or from sheep or lambskin from which the
grain has been removed by frizing, and tanned by processes involving
the oxidation of fish or marine animal oils in the skin, using
either solely such oils (full oil chamois) or firstly, aldehyde
and then such oils (combination chamois).
Note: France and the USA restrict
the term "chamois", without any qualification, to
the flesh split of sheepskin tanned solely with oils.
In Germany the term "Sämischleder"
is applied to an oil tanned suede leather made from sheep, lamb,
roedeer, red deer, chamois, goat and kid skins and cattle hide
splits.
In Italy and Switzerland this
leather is incorrectly termed "pelle di daino" and
"Hirschleder" respectively.
|
|
Chamois tannage
|
See: Oil tannage.
|
|
Chatter marks
|
Ridges
in leather caused by fleshing, shaving or splitting machines
where the cylinders are worn, poorly balanced or the bearings
on the grinders may be worn. “Wire edges” on the cylinder will
also cause chatter marks.
|
|
Chemical coagulation
|
Destabilisation of colloidal
particles brought about by the addition of a chemical reagent
known as a coagulant.
|
|
Chemical Oxygen Demand (COD)
|
Analytical determination
of the amount of oxygen chemically consumed by the oxidation
of the organic or oxidisable inorganic matter in an effluent.
Potassium dichromate is used as oxidant.
|
|
Chilling
|
Hides chilled down immediately
after flaying to between 8 °C and
10 °C can be stored over a
week, as is done today in some areas for fresh hide processing.
This chilling can be successfully achieved by distribution of
shredded ice on the flesh side of the hides and storage in boxes.
Dipping or spraying with chilled fresh water also can be used,
and is also in current practice.
|
|
Chlorinated hydrocarbon
|
Organic substance (hydrocarbons)
treated to combine with chlorine.
|
|
Chlorinated-paraffin wax
|
Solid, wax-like mixture of chlorinated
higher paraffin hydrocarbons.
|
|
Chloro Fluorocarbon (CFC)
|
Any of a class of gaseous compounds
of carbon, hydrogen, chlorine, and fluorine, used in refrigerants,
aerosol propellants, etc., and harmful to the ozone layer in
the earth's atmosphere owing to the release of chlorine on exposure
to solar ultraviolet rays.
|
|
Cholesterol
|
Sterol produced by
all vertebrate cells, particularly in the liver, skin and intestine.
It is a component of the animal fatty materials.
|
|
Chondroitin sulphate
|
Nitrogenous polysaccharide occurring in cartilage and
in the interfibrillary material of hides and skins in the form
of condroitinsulphuric acid.
|
|
Chromatic triangle
|
Triangular diagram with the three
primary radiations (red, blue, green) placed at the corners.
Mixing the primary colours, in varying proportions, it could
produce all the colours.
|
|
Chromaticity
|
Quality of a colour which is
defined by its dominant or complementary wavelength, taken together
with its purity.
|
|
Chromatin
|
Protoplasmatic substance in a
cell nucleus forming chromosomes, staining intensely with basic
dyes.
|
|
Chromatogram
|
Result of chromatography.
In Gas Chromatography (GC), High Performance Liquid Chromatography
(HPLC) and Ion-exchange Chromatography (IC), it is a diagram
where peaks represent different compounds separated by the chromatography
from a mixture.
|
|
Chromatography
|
Method of separating
and analysing mixtures of chemical substances. Note: Gel permeation,
thin layer, ion-exchange, two-dimensional, absorption, ascending,
column, descending, liquid, paper, partition. See: High Performance
Liquid Chromatography (HPLC)
|
|
Chrome (v); chroming
|
Treat hides and skins with chrome
liquor for tanning.
|
|
Chrome complex dyestuff
|
Anionic dyestuff containing metal
chrome complexes, type 1:1 or 1:2.
|
|
Chrome complex, (chromium) (cationic, anionic, neutral)
|
Complex formed by the co-ordination
of various ligands to one or more Cr+++ ions, which
may have a net positive (cationic), negative (anionic) or zero
(neutral) charge.
|
|
Chrome leather
|
Leather tanned either solely
with chromium salts or with chromium salts together with quite
small amounts of some other tanning agent used merely to assist
the chrome tanning process, and not in sufficient amount to
alter the essential chrome-tanned character of the leather.
|
|
Chrome liquor
|
Basic chromium sulphate liquor
prepared by reduction of a dichromate by glucose in the presence
of sulphuric acid.
|
|
Chrome mordant dye
|
Dye, which needs a mordant to fix.
Note: Chrome as a metallic salt
could be a mordant.
|
|
Chrome oxide
|
Dark green, amorphous
powder, forming hexagonal crystals on heating that are insoluble
in water or acids; used as a pigment to colour wares and as
a catalyst. Also known as chrome green.
The chromium content
of a chrome tanned leather and of a chrome tanning material
is usually expressed as chrome oxide (Cr2O3)
content.
|
|
Chrome retanned leather
|
Second tannage treatment of a
leather tanned with chrome tanning salt, and then with other
tanning materials.
Note: As vegetable tanning.
|
|
Chrome stain
|
Irregular
shaped darker coloured area on chrome leather, seen after tannage,
due to increased deposition of chromium compounds, often related
to too rapid basification.
|
|
Chrome tanning
|
Chrome tanning using a single
solution of a basic trivalent chromium salt, usually primarily
the sulphate.
|
|
Chrome tanning salt, (liquid; powder)
|
Commercial preparation of basic
chromium sulphate, of a certain basicity, containing more or
less of neutral salts; in the liquid, or powder, form.
|
|
Chrome-alum liquor
|
Basic chromium sulphate liquor
prepared from chrome alum by addition of an alkaline substance,
usually sodium carbonate.
|
|
Chromium
|
Metallic chemical
element, symbol Cr, atomic number 24, atomic weight 51,996.
· Hexavalent: the
hexavalent form (Cr+6 or CrVI) of chromium ion as
in chromates and bichromates. It has no tanning properties.
· Trivalent: the
trivalent form (Cr+3 or CrIII) of chromium ion as
in chrome sulphate, chloride, etc. This is the chrome tanning
form.
· Total: The chromium
content in leather, float, wastewaters, etc. in whatever form
it is.
|
|
Chromophoric group
|
Group of atoms, such as –N=N-,
-C=C-, =C=O, -N=O, in an organic substance which, when present
in suitable structural positions, and in sufficient numbers,
enables electron displacement to occur along the group or groups,
and gives rise to colour.
|
|
Chrysoidine
|
Monoazoic basic dye.
|
|
CITES
|
CITES is an abbreviation for
the Convention on International Trade in Endangered Species
of Wild Fauna and Flora. Also known as the Washington Convention,
as CITES was signed in Washington DC on 3 March 1973 and came
into force on 1 July 1975. The purpose is to control the exploitation
of wild animals and plant resources.
CITES has established a worldwide
system of controls on international trade in threatened wild
life and products derived from them by stipulating that government
permits shall be required for such trade.
|
|
Clarifier
|
Settling tank which allows activated sludge to be separated
from purified water.
|
|
Clariflocculator
|
Device in which the floc is settled.
The floc is obtained by agglomeration of destabilised particles
into microfloc and later in bulky flocules.
|
|
Classification (for chemicals)
|
European classification of chemical
substances or preparations explaining the risk associated with
their use.
The possible classifications
are : Explosive, Oxidising, Extremely flammable, Highly flammable,
Very toxic, Toxic, Harmful, Corrosive, Irritant, Sensitising,
Carcinogenic, Mutagenic, Reproductive toxic, Dangerous for the
Environment.
|
|
Claws
|
Pointed, horny nails or protrusions,
from the feet of certain animals and birds.
|
|
Clean (v); cleaning
|
Removing dirt, spots
and impurities from the surface of a material. It may be performed
dry and/or wet. For example, by solvent.
|
|
Cleanability
|
Ability of an upper or clothing
leather to be maintained in a clean and good condition.
|
|
Clear (v); clearing
|
Cleanse the leather grain surface
from grease, etc., prior to seasoning by rubbing over with a
solution of ammonia or lactic acid.
|
|
Clear grain
|
Grain surface free
from blemishes or stains.
|
|
Clear lacquer
|
Pigment-free transparent lacquer
used in finishes, especially as top coating agent.
|
|
Clone (v); cloning
|
Create genetically identical
copies of a population of organisms derived originally from
a single individual. To clone an animal or a plant means to
propagate or produce it as a clone, for example create genetically
identical copies.
A clone is an animal or plant
that has been produced artificially from the cells of another
animal or plant, and is identical to the original one.
|
|
Closed grain
|
Tight formation of
the surface grain on leather.
|
|
Clothing leather
|
Soft, flexible, non-stretchy,
grain or suede leather of a thickness suitable for clothing.
It may be made from full substance, or split, hides or skins
and tanned in various ways. Note: It should be fast to light,
perspiration and wet and dry rubbing and be capable of being
washed or dry cleaned.
|
|
Cloudy
|
Visible uneven appearance caused
by transparent or opaque whitish blush on the surface of the
finished leather.
|
|
Clumping
|
Aggregation of small particles
into larger ones, as a thick cluster, difficult to break up.
This process occurs if an aqueous solution is added to a powder
pigment instead of stirring the powder into the solution.
|
|
Coagulant
|
Soluble substance which under
certain conditions, such as rise of temperature, pH alteration
or chemical action, forms a semi-solid or jelly-like insoluble
precipitate, which can carry along fine suspended solids.
Note: Ferrous sulphate, organic
polyelectrolytes.
|
|
Coagulate (v); coagulating
|
Cause a substance in solution
to separate out as large particles, or to change to an insoluble
form and separate from solution as large aggregates.
Note: As do blood globulins when
their solutions are heated.
|
|
Coagulation (of finishing products)
|
Finishing products are often
susceptible to extreme temperatures. Frost will cause aqueous-based
finishes and especially thermoplastic binders to coagulate irreversibly.
Heat will cause irreversible coagulation of albumens and globulins.
|
|
Coagulation-flocculation
|
Process of injecting one or more
chemical products with the objective of destabilising dispersed
colloidal matter, aggregating it and then agglomerating it into
large separable particles.
|
|
Coarse emulsion
|
Emulsion in which dispersed droplets
are comparatively large.
|
|
Coarse grain
|
Grain
surface that is somewhat rough, due to the nature of the pelt
and the method of treatment during tannage etc., and in which
the hair or wool follicles are large, forming a prominent pattern.
|
|
Coarse woolled
|
Sheep having long, strong, coarse
fibre wool especially suitable for carpet manufacture, such
as various large mutton breeds of English origin.
The impression of coarseness
or fineness is given by the diameter of the individual fibre.
The smaller the diameter the finer the fleece cover will feel.
Coarse woolled sheep breeds are covered with a low density
wool coat of medullated ‘thick’ fibres that can have - in the
coarsest types - a diameter over 38 ìm (1000 ìm= 1 mm). Comparatively,
the finer wool types, such as merino, have a fibre diameter
of approx. 18 ìm to 26 ìm.
|
|
Coarse-pored leather
|
Leather whose grain
shows large pores which can be improved by buffing.
See: Fine-pored leather.
|
|
Coat (v); coating
|
Application of liquid system,
such as a dye solution, or a pigmented finish, to a material
such as leather.
See: Brushing; padding; spraying;
curtain coating.
|
|
Cockle (Keds)
|
Defect
on sheepskins (rib cockle), first recognisable after unhairing
and appearing on the grain surface as small, firm nodules, usually
over the butt, in lines running at right angles to the backbone
towards the flanks. It is due to infestation by keds. Scatter
or spread cockle is more diffusely spread over the skin and
has been linked to lice.
Note:
Ked - melophagus ovinus.
|
|
Coconut oil
|
Oil from the kernels of the fruit
of the coconut palm.
|
|
COD
|
See: Chemical
Oxygen Demand.
|
|
Coil
|
Continuous length
of material in a spiral shape like the thread of a screw. For
example, collagen helix.
|
|
Cold crack
|
Possible damage to a finish film
when the leather is flexed at low temperatures. Shoe uppers,
therefore, need cold crack stability.
|
|
Cold stuffing
|
Introduction of a mixture of
oils, fats and waxes into damp leather at room temperature by
hand, drumming or impregnation.
|
|
Cold sweating
|
Process of loosening the hair
or wool of hides or skins by keeping them damp and cool (up
to about 12 °C) so that bacteria develop and
attack the hair roots and lower epidermal layer.
|
|
Cold-stable
|
Oil which does not deposit solid
fatty matter on cooling to a specified temperature.
|
|
Collagen
|
Protein comprising the white
fibres of vertebrate connective tissue, such as the dermis of
skin, the matrix of bones and the dentine of teeth. Collagen
is the leather making protein of the hide. Collagen in the hide
or skin is perfectly structured to act as a protective covering
for all animals and these same features are ideally suited for
additional processing as an accessory for man (1997 IULTCS Congress,
London).
Dermis, the leather giving layer
of the hide or skin, after the removal of epidermis, hair and
flesh layer, is almost entirely collagen. In the animal kingdom,
this bio-polymer is unique in its amino acid composition, structural
diversity and physical properties.
The basic structure of the collagen
molecule is simple. The key to its ubiquitous presence is the
ability of nature to modify this simple structure so that the
biological diversity of the collagenous structures and their
functions are unequalled by any other protein.
At the time of the Centenary
Congress (1997) of the International Union of Leather Technologists
and Chemists Societies (iultcs)
in London, 19 genetically distinct collagens were known.
The fibres of the leather giving
layer dermis are copolymers of the major type I - fibrous collagen,
together with minor amounts of collagen types III (fibrous),
V (fibrous), VI (filamentous), and possibly XII (fibril associated
collagen).
See: Ageing; amino acid; angle
of weave; bond; dermis; denaturation;
structural features; hydroxyproline; isoelectric point; grain layer; papillary
layer; reticular layer; maturity; interfibrillary matter
|
|
Collagenase
|
Enzyme which hydrolyses collagen,
a substance that accounts for 75% of the dry weight of skin
tissue.
|
|
Colloidal suspension
|
Describes particles - often electrically
charged - which are dispersed in a fluid but fail to settle
naturally. This term is also used for fine suspended solids
which settle only with considerable difficulty. They can be
removed by coagulation - flocculation.
|
|
Colophony
|
Yellowish, glassy resin obtained
as a residue from the distillation of turpentine, an exudation
from certain pine trees.
|
|
Colour
|
Visual sensation produced on
the eye by radiation of bodies or substances, reaching it after
reflection or scattering by a surface or transmission through
a material. These special characteristics depending upon the
spectral composition of the wavelengths of radiant energy capable
of stimulating the return and its associated neural mechanisms.
This sensation is defined by
three characteristics: Value (or intensity), hue or tone, and
croma.
|
|
Colour (v); colouring
|
Apply or give colour to a material,
as by dyeing, painting or staining.
|
|
Colour base
|
Insoluble organic substance which,
when dissolved in acid, gives a dyeing cation.
|
|
Colour change
|
Alteration in the colour of a
coloured material produced by chemical treatment, alteration
of pH, light, etc.
|
|
Colour circle
|
Circle designed to exhibit the
proportion of primary colour in any shade of colour.
|
|
Colour levelness
|
Visible evenness of the coloured
surface of a dyed or finished leather.
|
|
Colour matching
|
Application of an adequate blend
of dyestuffs to a material, such as leather, to obtain and duplicate
the same colour as that of a sample in any kind of material.
|
|
Colour shop
|
Place (zone, area, or department)
where colour recipes are prepared.
|
|
Colour sorting
|
Classification of dyed skins
with similar colour for making a leather garment.
|
|
Colour stripping
|
Lose the colour from a material,
by chemical treatment or sunlight effect.
|
|
Colour triangle
|
Triangular diagram showing the
three primary colours (red, green, blue) placed at the corners.
Mixture of any two primaries will be found in the line joining
the corners, and the centre of the triangle will, theoretically,
be black..
|
|
Combination chamois
|
Chamois tanned by using aldehyde
prior to fish or marine animal oils.
|
|
Combination oil tannage
|
Tannage in which the skin is
treated with any suitable aldehyde, and then with an oxidisable
marine mammal or fish oil.
|
|
Combination tannage
|
Tannage with two or more tanning
agents of different types, usually applied separately in succession.
|
|
Combing leather
|
Strong, resilient, curried butt
leather, free from permanent stretch, made into endless belts
and used on machines for combing wool. It is chrome tanned (green)
or combination tanned (brown).
|
|
Comets/spots
|
If pigment
finishes are insufficiently mixed or filtered, a small spot
of solid pigment can cause a streak under a plating, polishing
or glazing machine.
|
|
Common Agricultural Policy (CAP)
|
Common Agricultural Policy of
the European Union.
|
|
Compacting container
|
Skip equipped with a press in
order to reduce the volume of solid waste it contains by increasing
its density.
|
|
Compactness
|
Property of a leather
with an internal structure of closely packed leather fibres.
|
|
Complementary colour
|
Either of a pair of spectrum
colours which when combined give a sensation of white or nearly
white light. One of two pigments whose mixture produces a third
colour, as blue and yellow blended to produce green.
|
|
Compost
|
Soil amendment obtained from
the biological aerobic treatment of waste containing organic
matter. During the biological
treatment, the temperature naturally rises up to 60 °C, followed
by a period of maturation, which stabilises the material. Before
use, it usually has to be sieved.
See: Composting.
|
|
Compost heap
|
Composting technique in which
waste is disposed in heap that is turned over to improve aeration.
|
|
Compost (v); composting
|
Production of compost by breaking
down the organic matter contained in sludge or organic waste.
See: Compost.
|
|
Compressibility
|
Property of a substance
capable of being reduced in volume by application of pressure.
|
|
Concentration
|
Amount of a chemical substance,
in a material, water, solid waste. It is generally expressed
in %, mg/l, mg/kg or mg/kg dry solid.
|
|
Condensation tannage
|
Resin tannage in which insoluble
high-molecular compounds are formed within the leather by inter-condensation
of previously introduced methylol compounds of nitrogenous bases,
such as urea, melamine, etc.
|
|
Condensed tannin
|
Tannin of the class which, in
contrast to the tannins of the hydrolysable class, cannot be
split into simple units by enzymes or dilute acids, its molecule
being composed of polyphenol units joined by carbon-to-carbon
linkages or carbon chains.
|
|
Condition (v); conditioning
|
After drying, the leather may
be hard and of uneven moisture content. Moisture is re-introduced
into the leather to a level that is suitable for subsequent
mechanical actions such as staking or milling.
The term is also used for
bringing leather into equilibrium in a standard atmosphere before
physical leather testing. Note: Test methods, IUP 3.
|
|
Conditioning plant
|
Plant able to keep
pre-arranged conditions in a room or cabinet. Note: Humidity
and temperature.
|
|
Connective tissue
|
Type of mammalian tissue, composed
essentially of collagen, elastin and reticulin fibres, together
with various types of cells, blood vessels, nerves, ground substance,
etc., forming the dermis, areolar tissue, tendons, bones, walls
of most organs, etc.
|
|
Conservation
|
Conservation means to increase
the shelf life of a decomposable - putrecible- material, as,
for example, the raw hide, by destroying the germs responsible
for its decay (breakdown) or by retarding their growth (1922).
See: Curing; short-term curing;
air drying; disinfectant.
|
|
Control guard
|
Guard associated with an interlocking
device (with or without guard locking) so that :
- the hazardous part of the machine
function is covered by the guard and cannot operate until the
guard is closed
- closing the guard initiates
operation of the hazardous part of the machine function(s).
|
|
Control of Substances Hazardous to Health (COSHH)
|
Control of Substances Hazardous
to Health Regulations.
|
|
Conveyor
|
Mostly used as endless conveyor
band to transport hides and skins or leather to or from a machine.
In finishing, the conveyor band carries the flat leather through
the spraying machines beneath the spray guns.
|
|
Cool (v); cooling
|
Become or make cool, or cooling
an object or a physico-chemical system by heat transfer
to other cooler objects or systems.
|
|
Copolymerisation
|
Chemical reaction forming a polymer
by mixing two or more monomers.
|
|
Cordovan
|
Originally a fine grain, coloured
Spanish goatskin leather.
|
|
Cordovan
|
Leather made from the shell of
a horse butt, that is from a kidney-shaped, very compact layer
occurring in the butt of equine animals only, and isolated by
removing the skin layer above and below it. It is vegetable
tanned and curried.
Note: In Holland leather sold
as "cordovan leather" is not necessarily made from
horse hide.
|
|
Corium
|
Corium or dermis is the central
layer of the hide or skin remaining after the removal of epidermis,
hair and flesh (flesh side), and which is converted into leather.
This layer amounts to approximately 95% to 98% of the total
thickness of a hide or skin.
The dermis consists of an upper
papillary zone (layer papillary) adjacent to the epidermis,
and a lower reticular zone (layer reticular) which blends with
the underlying adipose layer. Although no sharp line of demarcation
is usually found between the zones, the boundary defined by
the lowest hair or wool roots may be taken as the dividing line
between the papillary and reticular zones. The papillary dermis
is commonly referred to as the grain layer (also known as thermostatic
layer), and the reticular dermis as the corium proper. The reticular
dermis is the main layer of the hide or skin. This layer is
composed mainly of interwoven collagen fibres arranged in well
defined bundles.
The fibre bundles of the reticular
dermis or ‘corium proper’ are relatively much larger than those
of the grain. The structure of the reticular dermis which also
varies with the species, age and sex of the animal is responsible
for many of the characteristics of leather.
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Corrected grain
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Leather which has
had the outer surface of the grain removed by an emery wheel
to delete or “correct” blemishes. Also known as snuffed grain.
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Cortex
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Main structural component of
hair and wool, covered by the scaly cuticle and consisting of
cigar-shaped cells, arranged parallel to each other.
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COSHH
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See: Control of Substances Hazardous
to Health.
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Cotton dyestuff
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Direct dyestuff able directly
to dye cotton materials.
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Counter
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Stiffener or reinforcement
in the back part of the shoe to retain shoe shape and offer
stability and support to the heel of the foot. The counter may
range from soft to rigid. It can be premoulded or flat and then
moulded to the last by pressure.
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Couple (v); coupling
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Join by means of the azo group
(-N=N-), the aromatic nuclei from two or more organic compounds.
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Coupling dyestuff
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Dyestuff which can be formed
within a fibre by diazotisation treatment.
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Cover
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Poor covering
of defects or colour irregularities on the leather surface.
The cause can be type of pigment, colour of the leather, pigment
to binder ratio and excessive penetration of the base coats.
Poor cover of full grain leather may be due to damaged grain
enamel, abraded grain, etc.
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Covering power
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Ability of pigments in the finish
coat to cover irregularities on the surface of a leather.
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Crack
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Break appearing on
the surface when a leather is under the strain of lasting, bending
or pulling.
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Crackiness
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Tendency of a leather
to crack. See: Cracky grain.
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Cracky grain
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Grain
layer which breaks when the leather is pulled or bent. Grain
crack could be caused by many factors such as chemical damage,
poor lubrication, excessive tannage in the grain, etc.
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Cream (v); creaming
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Form a concentrated layer (thick
oily, light-yellow substance) in a fatliquor, when the fatty
globules rise to the surface.
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Crease
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Undesired fold marks in leather
caused by improper handling during mechanical processes in leather
manufacturing.
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Crinkled patent
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Soft patent leather with a creased
or crumpled appearance produced mechanically after the patent
finish has been applied and dried.
Note: Same as crushed patent.
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Crock (v); crocking
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Leather
which is not colour fast when rubbed with a white cloth, wet
or dry, is said to “crock”. The colour transfer may be due to
loose dye and/or loose dust.
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Crop (v); cropping
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Cut the bellies from sole leather
hides or sides after tanning in the layer vats.
Note: USA origin.
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Cross coat
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Coating formed by two successive
applications of a liquid preparation at right-angles to each
other. The term is usually applied to hand spraying.
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Cross-breeding
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To breed between two varieties
of breeds of the same species. Breed crosses are very common;
wool and mutton type sheep,
Zebu or Brahman cattle with European breeds, Criollo
with Shorthorn, Angus with Hereford, Shorthorn x Angus x Hereford,
etc.
The objectives of cross breeding
seldom coincide with the need of the tanner for quality hides.
Since its start, the main use of cross breeding has been the
production of a commercial, more lucrative livestock.
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Crosslink
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Chemical links between
the molecular chains of polymers.
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Crosslinking agent
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Highly reactive products like
polyisocyanates or polyfunctional aziridine compounds to achieve
film-forming properties of different finish formulations. Relevant
safety regulations should be observed.
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Crosslinking reaction
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Process of joining free polymer
chains with each other by side linkages to form a two or three
dimensional network.
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Crushed patent
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See: Crinkled patent.
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Crust (dyed) leather
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Dyed leather dried out directly
after postanning process.
Note: Vegetable, chrome or combination
tanned.
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Crust leather
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Leather which, after tanning,
has not been further processed but has been merely dried out.
Note:
In France the term "en croûte"
is applied to any kind of hide or skin, such as "mouton
en croûte, veau en croûte", and to any part of a hide,
such as “collet en croûte, croûte en croûte”.
In the UK the term "crust"
is used in connection chiefly with skins such as sheep, whilst
the term "rough tanned" is similarly employed in connection
with cattle hide leather.
In Italy, the term is also used
for dyed and dried leather.
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Culata
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Italian and Austrian term for
the rear part of a bovine hide, comprising the butt, the belly
middles and the hind shanks (see figures J and K on the ‘International
Glossary of Leather Terms - Schema’). French term for a more
or less wide un-squared rear section of a cattle hide butt including
the tail piece.
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Cure (v); curing
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Curing essentially consists of
bringing about varying degrees of dehydration of the hide or
skin either by simple drying or by salting; the curing salt
itself acting as an additional inhibitor of putrefaction. As
the percentage of hides put into work by the tanner within 24
hours of flaying is very small, the great majority of hides
have to be preserved or ‘cured’ for transport and storage.
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Cured weight
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Weight of a hide or skin after
curing by treatment with sodium chloride (wet-salting, brining)
or other chemical or natural curative agent or process.
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Curing salt
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Common salt of appropriate composition
and grain size for salting hides and skins. May contain denaturants
or additives to improve its preservative properties.
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Curried leather
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Leather, usually vegetable tanned,
which has been subject to the currying process, that is a series
of dressing and finishing processes applied to leather after
tanning, in the course of which appropriate amounts of oils
and greases are incorporated in the leather to give it increased
tensile strength, flexibility and water-resisting properties.
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Curtain coating
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Application of a liquid finish
from a supply tank, in the form of a long, thin film, onto the
leather surface as it passes on a conveyor through the curtain
coating machine. Unspent float flows back into the supply tank
and is continuously recirculated.
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Cut
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1. Inner part of
a leather revealed by cutting perpendicular to the surface to
examine for penetration of chemicals, dyes, etc. and for microscopical
observation;
2. Cut produced by
the knife on the flesh side of the hide due to bad flaying.
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Cuticle
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The hairs of most animals are
of two types, primary and secondary. The primary hairs are the
more numerous and are made up of three concentric cylinders,
the medulla, an inner region of large columnar cells surrounded
by a cylinder of smaller, spindle-shaped cells (the cortex),
the whole being contained in the cuticle, a very thin layer
of flat overlapping cells.
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Cylinder plating
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Continuous through-feed cylinder
plating machine with the desired plating effect and film forming
influenced by temperature and time of contact with the plating
surface, as well as by pressure.
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