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Tackiness
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Condition
of tackiness, which may be slight or may involve permanent sticking,
sometimes develops in a finish after application. The use of
too much plasticiser and the improper drying of base coats may
be factors that cause tackiness.
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Tailings
|
Partially exhausted, ground tanning
material obtained when layer pits are emptied.
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Tail-liquor
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More or less exhausted suspender
liquor to be run away from the bottom suspender pit.
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Taint
|
Damage
to the grain is very noticeable and is caused by putrefaction
due to delays in curing or from insufficient salting. Also know
as salt prick, grain slip, grain peeling. Salt prick is characterised
by a superficial pitting effect; grain slip involves larger
areas and grain peeling is extensive damage which may result
in areas of the skin actually dissolving during the leather
making process.
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Take-up (v); taking up
|
For a material, to remove a dyestuff
(or a dyeing auxiliary) from a solution.
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Tallow
|
Fat, or adipose tissue, of cattle,
sheep and goats.
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Tamarisk (tamarix)
|
Ground leaves and twigs sometimes
used as sumach adulterant.
Note: Tamarix africana.
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Tan (colour)
|
Brownish colour resembling that
of typical vegetable tanned leather.
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Tan (v); tanning
|
Treating prepared hides or skins
with suitable chemicals to give a fibrous product, imputrescible
when wet, more or less soft and flexible when dry and capable
of being wetted and dried without loss of these
properties.
Note: Hides and skins are composed
of collagen in a fibrous structure. The aim of tanning is to
form irreversible chemical crosslinks to the collagen matrix
to prevent degradation by bacterial, chemical or thermal action.
Commonly used tanning agents, applied individually or in combination,
are chrome (III) salts, giving a typically blue coloured leather,
synthetic tanning agents, and organic vegetable tannins which
give a characteristic pale brown colour. Various other metallic
products such as aluminium and zirconium are also available
as tanning agents.
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Tan cake
|
Blocks of compressed, and sometimes
dried, spent tan for use as fuel in boilers.
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Tannage
|
Term used in describing a special
type of tanning method, such as chrome tannage, quick tannage.
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Tanned
|
Converted into leather.
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Tanner
|
People whose job is to convert
animal hides or skins into leather by any process.
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Tannery
|
An establishment where hides
or skins are converted into crust, wet tanned or finished leather.
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Tannin
|
General term for the active tanning
principles contained in vegetable tanning materials.
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Tannin balance
|
Distribution of the actual amount
of tannin introduced into the tanning process in the finished
leather (in the fixed and water-extractable forms), in the various
liquors and somehow lost in process.
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Tanning degree
|
Empirical way to
evaluate the amount of tanning. It is expressed by the ratio
between the total amount of organic tannins bound to the leather
and the hide substance.
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Tanning liquor
|
Solution of tanning agent.
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Tanning process
|
Operation in leather manufacture
involving the treatment of the prepared pelt with the tanning
agent.
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Tannin-non-tannin ratio
|
Relation between the tannin and
the non-tannin contents of a vegetable tanning material, such
as tannin per 100 parts non-tannin.
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Tan-through
|
Penetrating and tanning the pelt
completely.
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Taran
|
Tannin-containing root of Polygonum
alpinum, growing in the Caucasus and the Altai mountains.
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Taw (v); tawing
|
Converting to leather with a
mixture of alum, or aluminium sulphate, salt, wheat flour and
egg yolk.
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Tawed leather
|
Leather prepared with a mixture
of which the essential active ingredient is an aluminium salt,
formerly, but not necessarily today, alum.
Note: Alum, salt, egg yolk and
flour. The natural colour of the leather is white.
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Tawing paste
|
Mixture of alum, or aluminium
sulphate, salt, wheat flour and egg yolk for use in tawing or
alum dressing.
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TCMTB
|
See: (2-Thiocyanomethylthio)-Benzothiazole.
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TDS
|
See: Total Dissolved Solids.
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Tear
|
Caused
by sharp objects on the living animal hide; damage during transit
by hooks, forklift trucks, etc. Mechanical machine damage in
tannery processing.
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Telopeptide
|
Peptide located at the end of
the collagen polypeptide chain. A non-helical region. Telopeptides
are split-off, for example, by pepsin.
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TEM
|
See: Transmission
Electron Microscopy.
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Tender grain
|
Grain surface which
for some reason, such as excessive acidity of the leather, is
easily damaged by pulling, bending and rubbing.
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Tenderness
|
Tendency of a leather
to break due to the fragility of the fibres or of the fibre
texture.
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Tensile strength
|
Measure or test of
a material extended at a specific rate until the forces reach
a predetermined value or until the material breaks. The tensile
strength is recorded in Newtons per square millimetre and there
are facilities for recording the percentage elongation caused
by a specific load, and the percentage elongation at break.
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Thermolysis
|
See: Pyrolysis.
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Thermoplastic
|
Property of a polymeric substance
which, under thermal influences, becomes soft and plastic.
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Thermoplastic binder
|
Polymer binders used to achieve
film-forming and impart required properties to finish coats.
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Thickener
|
Auxiliary used in finish formulations
to increase the viscosity.
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Thin Layer Chromatography (TLC)
|
Chromatographing
on thin layers of adsorbents rather than in columns; adsorbent
can be alumina, silica gel, silicates, charcoals or cellulose.
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Thinning agent
|
Auxiliary used in finish formulations
to reduce the viscosity.
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Thio compound unhairing
|
Removal of hair or wool from
hides or skins by thio compounds.
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Thirds
|
Class of hide or skin suffering
from certain defects which are more or less closely defined
and which depend upon the type of skin (cattle hide, calfskin,
goatskin, etc.) and the country of origin; not necessarily the
lowest grade.
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Three dimensional weave
|
Interlacing, or running of the
fibres and fibre bundles of the dermal tissue (dermis) in the
three dimensions.
See: Structural features.
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Threshold Limit Value (TLV)
|
Concentration threshold which
is set specifically for each pollutant. Refers to the limit
accepted in the atmosphere of a working area (workshop, etc.).
Is expressed in ppm or in mg/m3.
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Threshold Limit Value - Short Term Exposure Limit (TLV
- STEL)
|
Refers to a permissible 15 minutes
exposure in an atmosphere contaminated with a specific type
of pollutant.
The concentration requirement
must be fulfilled at any moment during the working period.
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Threshold Limit Value - Time Weighted Average (TLV - TWA)
|
Refers to a permissible exposure
in an atmosphere contaminated with a specific type of pollutant.
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Through-dyeing
|
Dyeing of a leather throughout
its substance or whole thickness.
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Through-dyeing ability
|
Ability of a dyestuff to dye
leather throughout its substance or whole thickness.
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Through-feed
|
Passing a material through a
machine by a conveyor, for example, an automatic spraying machine.
Also, machines such as fleshing machines that flesh the hide
in one pass, straight through the machine, instead of reverse
feed out.
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Through-feed dryer
|
Drying of leather in cabinets
or tunnels by a through-feed circulatory system.
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Tick
|
Small
blood-sucking insect living on the skin of animals. Causes small
pits or scars over the animal’s skin.
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Time lag
|
The time between the animal being
flayed and the period when the preservation agent (for example,
salt) becomes effective against the bacteria present in the
hide or skin.
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Tinctorial power
|
Measure of the relative colour
strength of a dyestuff.
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Tint
|
Stronger or weaker variety of
a colour.
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Tint (v); tinting
|
Alter the colour of a material
slightly.
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Tinting dyestuff
|
Dyestuff which gives a subtle
alteration to the colour of a material.
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Tip (v); tipping
|
Colour the natural or artificially
produced protuberances and elevations on a leather surface.
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Tip coloured mohair velours
|
Coarse long-haired suede, surface
dyed, with the ends of the fibres of a different, usually lighter,
colour to the base colour of the suede, produced by mechanically
teasing the flesh side to lengthen the fibre.
Note: Also known as "Tip
coloured shaggy suede".
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Tip dyeing
|
Application of dye to natural
or artificially produced protuberances on the leather surface
by means of a firm pad.
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Tip-reserve
|
Process for obtaining a two-tone
effect on furskins by applying a “resist” to the tips of the
hairs before dyeing.
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Tissue
|
Association of large numbers
of cells, fibres and other cell products in an animal or plant
body, having a common origin and performing a specialised function.
Note: Epithelial, connective,
muscular, nervous and blood tissues.
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TKN
|
See: Total Kjeldahl Nitrogen.
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TLC
|
See: Thin Layer
Chromatography.
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TLV
|
See: Threshold Limit Value.
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TLV- STEL
|
See: Threshold Limit Value -
Short Term Exposure Limit.
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TLV- TWA
|
See: Threshold Limit Value -
Time Weighted Average.
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To and fro rubbing
|
Test to evaluate
the effect of rubbing a material such as leather with another
(felt) with a “to and fro” alternating movement.
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TOC
|
See: Total Organic Carbon.
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Toggle (v) ; toggling
|
The straining and fixing of leather
onto frames with toggles. The purpose is to dry leather keeping
it under tension.
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Toggle dryer
|
Dryer in which the leather is
dried whilst held under tension on frames by toggles.
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Tone (colour)
|
Net effect produced on the eye
by the mixture of radiations reflected, emitted and/or scattered
by a material.
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Tone (v); toning
|
Adjust, correct or shade a colour,
by subsequent addition of a dye.
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Top (v); topping
|
Make a second application of
the same, or another, dye on top of a previous dyeing.
Note: Cationic dyeing on top
of an anionic dyeing.
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Top coat
|
Final top coat applied in the
finishing process.
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Top grease
|
Finishing coating of a grease
mixture applied to leather, to give it special properties, such
as gloss, or waterproofness.
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Total carbon emission
|
Emission to the atmosphere of
organic compounds calculated in carbon equivalent.
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Total Dissolved Solids (TDS)
|
Quantity of dry material in a
solution after its filtration.
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Total fatty acids
|
Content of higher fatty acids,
free and combined, in a material.
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Total Kjeldahl Nitrogen (TKN)
|
Determination of all nitrogen
in a sample excluding ammonium nitrogen.
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|
Total Organic Carbon (TOC)
|
Indicates the content of carbon
linked to organic material by measuring the CO2 after
complete oxidation.
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Total Solids (TS)
|
Total content of suspended and
dissolved solids in a liquid or gas.
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Total Suspended Solids (TSS)
|
Total nonfiltrable residue on
a standard glass fibre filter dish, after filtration and drying
at 103 °C to 105 °C for a minimum of 1 hour.
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Toxic
|
Product or preparation which
may lead to death or acute or chronical health injuries when
inhaled, swallowed or absorbed through the skin in small quantities.
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Toxic (reproductive)
|
Substances or preparations which,
by inhalation, ingestion or in contact with the human skin,
could increase the frequency of fatal non-hereditary effects
for the offspring or undermine the reproductive capacity of
humans.
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Transfer finish
|
Thin film of transparent or pigmented
polyurethane on a paper or other suitable carrier which can
be transferred onto a leather surface previously coated with
adhesive, by heat and pressure.
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Transfer foil
|
Special ready-to-use finish film
on a backing or carrying material to be transferred onto a leather
surface. Note: Gold leather.
|
|
Transmission Electron Microscopy (TEM)
|
Type of electron
microscopy in which the specimen transmits an electron beam
focused on it, image contrasts are formed by the scattering
of electrons out of the beam, and various magnetic lenses perform
functions analogous to those of ordinary lenses in a light microscope.
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|
Trapped moisture
|
Can occur
in foam finishing systems. If the finish is dried at too high
a temperature initially, a surface film may form, trapping moisture
underneath.
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Tray dyeing
|
Process of dyeing in which pairs
of skins, placed flesh to flesh, are repeatedly drawn through
a dye solution contained in a tray.
|
|
Trim (v); trimming
|
Cut away useless or unwanted
material from the edges of raw or tanned hides or skins to give
them a better shape.
|
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Trimmings
|
Solid waste generated at the
trimming step (tannery).
|
|
Trough dyeing
|
Dyeing process in which the skins,
usually paired flesh to flesh, are repeatedly dipped into, and
removed from, the dye liquor contained in a trough.
See: Immersion dyeing, Dip dyeing.
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|
Ts
|
See: Shrinkage
temperature.
|
|
TS
|
See: Total Solids.
|
|
TSS
|
See: Total Suspended Solids.
|
|
Tumble (v); tumbling
|
Subjection of hides, skins or
leather to mechanical action in a revolving drum fitted internally
with pegs or shelves, in the dry state, alone in the damp state
or together with liquor, molten grease, etc.
|
|
Tunnel dryer
|
Dryer consisting of a long tunnel
through which the leather is carried whilst subjected to a counter-current
of heated air.
|
|
Turbidity
|
Gives an initial indication of
the level of colloidal matter of organic and inorganic origin.
It is judged either by comparing the sample with reference opalescent
solutions or by measuring the limit of visibility.
|
|
Turkey tracks
|
Occurs
in either forward or reverse mode of roller coating giving a
pattern to the finish similar in configuration to that of the
foot of a turkey. The main cause is the film-forming properties
of the finish being incorrect.
|
|
Two-component polyurethane lacquer
|
Reactive polyurethane system.
Polyester or polyether polyols are mixed with exactly measured
quantities of a crosslinking agent such as isocyanate, aziridine
or carbodiimide before application. The final reaction which
forms polyurethane occurs on the leather surface.
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|
Two-dimensional chromatography
|
Chromatographic technique
(paper or Thin Layer Chromatography - TLC) in which the sample
is resolved by standard procedures (ascending, descending or
horizontal solvent movement) and then turned at right angles
in a second solvent and resolved.
|
|
Two-tone effect
|
Showing two tones of colour.
|
|
Two-way suede
|
Long and soft, fibred suede leather
made and finished to show the mark of a finger drawn across
it.
|
