|
Pad (v); padding
|
Application
of finish coats, by manual padding with a plush-covered pad
or by a padding machine using pads, mechanically moving to and
fro across the leather surface.
|
|
Pad marks
|
Marks
left by a plush-covered pad used for applying pigment finish.
The marks are visible as streaks and can be caused by an uneven
surface on the pad or poor flow-out of the finish.
|
|
Paddle (vat)
|
Semi-cylindrical vessel (of metallic,
wood, concrete or plastic materials) fitted with a revolving
paddle wheel for keeping skins and liquors in motion. This type
of vessel could be used in different beamhouse processes such
as soaking, liming, and rinsing.
|
|
Paddle dyeing
|
Dyeing in a paddle or vat fitted
with rotating blades, to keep the contents in motion.
|
|
Paddle liming
|
Liming of hides, or skins, in
a paddle.
|
|
Paint (depilatory)
|
Pasty, aqueous mixture, applied
to the flesh side of certain hides and skins, especially sheep
and goat skins, to loosen the hair or wool.
Note: Mixture of slaked lime
and sodium sulphide or of an enzyme and a thickener.
|
|
Paint (v); painting
|
Application of a pasty, aqueous,
depilatory mixture (paint) to the flesh side of certain hides
or skins, especially sheep and goat skins, to loosen the hair
or wool.
|
|
Paint marks
|
Water resistant and lightfast
pigment formulation applied to a domesticated animal (especially
sheep), that indicates its owner, class, etc.
|
|
Painted hair
|
Hair removed from hides or skins
after loosening by application of a depilatory paint to the
flesh side.
|
|
Painted wool
|
Wool removed from sheepskins
after loosening by sulphide paint applied to the flesh side.
|
|
Pancreatic enzyme
|
Enzyme originating from the pancreas,
often used in bating.
|
|
Papillary layer
|
Papillary dermis is commonly
referred to as the papillary layer
or the ‘thermostat layer’. The papillary dermis or thermostat
layer contains hair, hair follicles, sebaceous glands, sweat
glands, erector pili muscles, etc. Surrounded and supported
by connective tissue (collagen) fibres.
|
|
Parchment
|
A translucent or opaque skin
material, having a smooth surface, suitable for manuscripts,
bookbinding and other purposes. Made from calf, sheep and other
unsplit skins by drying the dehaired, limed skin without applying
any tannage, the material being thoroughly cleansed and degreased
and the grain surface being smoothed during the process. In
the UK parchment is made from the flesh split of a sheepskin.
In other EU countries parchment may be made from any type of
skin.
See: Vellum.
|
|
Paste (v); pasting
|
Mix a
dye powder with water or other liquid, to obtain a paste for
dyeing.
|
|
Paste (v); pasting
|
Process
of sticking wet leather to a smooth plate for drying.
See: Paste
drying.
|
|
Paste drying
|
Drying method mostly used for
upper leather with corrected grain. A glass plate is covered
with a thin starch paste and the wet leather is slicked out,
grain side to the glass, to which it adheres thereby preventing
shrinkage on drying in the drying chamber.
|
|
Pastel
|
Character of a delicately coloured
surface, scattering, emitting and/or reflecting a high proportion
of incident white light.
|
|
Pasteurisation
|
Pasteurisation aims at making
a product aseptic. By way of example, the use of sludge on pastureland.
Pasteurisation can be achieved by heating the sludge to 70 °C for 30 minutes.
|
|
Pasting agent
|
Glue, such as carboxymethyl-cellulose
or starch paste, used to stick the wet leather on to the glass
plate during paste drying.
|
|
Patchiness
|
Uneven
colour due to irregular uptake of dyes.
|
|
Patent laminated leather
|
Plastic surfaced laminated leather
with the appearance of patent leather.
|
|
Patent leather
|
Leather with a lustrous mirror-like
surface, built up by the application of one or more coats or
daubs, varnishes or lacquers, pigmented or non-pigmented, based
on linseed oil, nitrocellulose, polyurethane and/or other synthetic
resins.
Note: In certain countries laminates
of a similar appearance may be classed as patent leather, but
different countries limit the proportion or thickness of the
plastic film in different ways.
|
|
PCP
|
See: Pentachlorophenol.
|
|
Pearlised leather
|
Coloured leather with a pearlised
lustre.
|
|
Pebbled grain
|
Wrinkled
grain layer caused by the corium contracting during the tannage
more than the grain layer, which therefore seems to be “drawn
up”. Can be caused by excessive agitation in the process vessel
or chemically. See: Drawn grain.
|
|
Peccary
|
Grain leather, mainly gloving,
made from a wild boar indigenous to Mexico, Central American
countries, Brazil and Argentina.
|
|
Peel (v); peeling
|
Undesired removal of a thin layer
of finish from the leather surface.
|
|
Peeling Grain
|
Grain
layer separates from the corium. Usual causes are too high a
temperature during storage and processing, as well as bacterial
damage.
|
|
Pelt
|
Skin in the trimmed, dehaired
or dewoolled, limed, fleshed, perhaps bated, and scudded condition.
In other words, the isolated corium layer more or less ready
for tanning.
|
|
Pelt split
|
Split in the fully hydrated and
untanned state, as cut from skins after removal of the hair
or wool, epidermis and flesh layer.
|
|
Pelt trimmings
|
Pieces cut from pelt to give
them a satisfactory shape.
|
|
Pelt weight
|
Weight of pickled, dewoolled
sheepskins.
|
|
Penetrate (v); penetrating
|
Enter one material into or through
another.
Note: Liquor, solution or dissolved
chemical, into leather.
|
|
Penetrating ability (of a dyestuff)
|
Ability of a dyestuff during
dyeing to penetrate into the interior structure of a material.
|
|
Penetration time
|
Time needed for the
required degree of penetration of a chemical into the inner
layers of the leather.
|
|
Penetrative dyeing
|
Dyeing which penetrates deeply
into a material.
|
|
Penetrometer
|
Device to measure
the dynamic water resistance of flexible leathers. The penetration
time, water absorption and water transmission are all recorded.
|
|
Pentachlorophenol (PCP)
|
Chemical substance sometimes
used as a preservative in leather, wood, cotton and other natural
materials.
|
|
Peptidase
|
An enzyme which hydrolyses the
peptide links of polypeptides, though not of native proteins.
|
|
Peptide
|
Any compound in which two or
more amino acids are linked together in a linear sequence, the
carboxyl group of each acid being joined to the amino group
of the next. Depending upon the number of amino acid residues
per molecule, they are known as dipeptides, tripeptides, and
so on, and finally polypeptides.
|
|
Perch (v); perching
|
Softening and stretching method
for light leathers by means of a perching machine with a bladed
cylinder.
|
|
Perchloroethylene washing fastness
|
Fastness (mainly
colour fastness) of a dyed leather to a perchloroethylene washing test (dry cleaning).
|
|
Perforation
|
Holes punched in
shoe uppers for decorative effect. The holes are punched by
machine according to pre-designed patterns, usually before the
parts are stitched together.
|
|
Permeometer
|
Device for measuring
the coefficient of permeability by measuring the flow of fluid
through a sample across which there is a pressure drop produced
by gravity.
|
|
Persian
|
Crust, vegetable tanned leather
made from the hair type sheepskin originating in the Indian
sub-continent and tanned in India, mainly in the South, and
especially around Madras (Chennai).
|
|
Persian
|
Leather made from crust, vegetable
tanned leather made from the hair type sheepskin originating
in the Indian sub-continent and tanned in India, mainly in the
South, and especially around Madras (Chennai).
|
|
Persian skiver
|
Thin grain layer, split after
dressing from an E.I. (East Indian) tanned sheepskin.
|
|
pH
|
Term used to describe
the hydrogen-ion activity of a system, that is the acidity or
the alkalinity. The pH range is generally from 0 to 14, with
pH 7 being neutral. Less than pH 7 is acid, with pH 0 being
the strongest acidity. Above pH 7 is alkali, with pH 14 being
the strongest alkalinity.
|
|
pH Difference figure
|
Difference between
the pH of a solution, for example, water extract of a leather,
and the pH of the same solution diluted ten-fold. It is an index
referring to the amount of free acid. Often shown as “D pH”.
|
|
Phlobaphenes
|
Reddish-coloured, more or less
insoluble condensation products formed by the condensed tannins,
such as quebracho, mimosa and oak barks, when their solutions
are boiled with acid or are allowed to stand.
|
|
Phosphatide tannage
|
Tannage with phosphatide-containing
materials, such as brains, bone marrow and egg yolk.
|
|
Phospholipids
|
Compound whose products of hydrolysis
include fatty acids and phosphoric acid; any lipid containing
phosphoric acid, especially one with a structure based on glycerol
phosphate.
|
|
Picking band leather
|
Butt or sometimes shoulder leather
with or without the hair, combination tanned (such as oil/vegetable)
or chrome tanned, curried to produce leather with high tensile,
tear and flexural strength, for use on textile looms.
|
|
Pickle
|
Acid liquor, such as sulphuric
acid and sodium chloride, used to preserve pelts and hides and
to prepare them for tanning.
|
|
Pickle meal
|
Pickle prepared from fermented
oats, barley, etc., and salt.
|
|
Pickle (v); pickling
|
Treatment of pelts with an acid
liquor, such as a solution of sulphuric acid and sodium chloride,
to preserve them or to prepare them for tanning, especially
chrome tanning.
|
|
Pickle creases
|
Occurs
during the storage and/or transport of pickled stock. The creases
are caused by the partial drying out of the stock.
|
|
Pickled weight
|
Weight of hides or skins after
the pickling process and draining to approximately 55% to 60%
moisture.
|
|
Pigment coat
|
Finishing coat using organic
or inorganic pigments in the finish preparation.
|
|
Pigment finished leather
|
Leather to whose surface a finish
containing fine pigment particles in suspension has been applied.
Sometimes called “doped”.
|
|
Pigment paste
|
Homogenised, finely dispersed
pigment paste manufactured by chemical suppliers. Mainly offered
with ready-to-use consistency.
|
|
Pigskin
|
1. Skin of a swine; in Britain
the term applies to all swine; in the United States to younger
swine weighing less than 50 kilograms, the ‘heavier’ being called
‘hog’; hog-skin = pigskin.
2. Leather made of pigskin.
|
|
Pile (v); piling
|
Lay wet tanned hides flat in
a pile to drain and allow the tanning agent to become fixed.
|
|
Pilling
|
Forming
of small balls when a resin finish is applied by padding or
brushing. Usually caused by the presence of buffing dust or
poor mechanical shear of the resin. See: Balling
up.
|
|
Pin seal
|
Seal skin leather with a characteristic
very fine pinhead pattern obtained by hand boarding.
|
|
Pinhole - Bovine
|
Enlargement
of the individual hair follicles due to bacterial damage.
|
|
Pinhole - Ovine
|
Defect
of fine woolled sheepskins consisting of prominent small holes
penetrating the skin to a considerable depth but not through
it. Caused by the gaps left
by groups of wool fibres which grow together in clumps
and are pulled out together during dewoolling.
|
|
Pinned vegetable sole leather
|
Set out and rolled leather made
from vegetable tanned cattle hide belly or shoulder.
|
|
Pit liming
|
Liming of hides, or skins, in
a pit.
|
|
Pit salted
|
Curing of hides and skins by
placing in a pit one by one, flesh-side upwards, sprinkling
each with solid salt as it is introduced and leaving in its
own liquor until required.
|
|
Pit soaking
|
Soaking of hides or skins in
a pit.
|
|
Pit tannage
|
Tannage, mostly for vegetable-tanned
sole leather, carried out in a series of pits.
|
|
Pitting
|
Indentations
in the grain of the hide caused by large crystals of salt. The
pressure of the pile of hide adds to the formation of pitted
areas.
|
|
Plastic surface laminated leather
|
Leather covered with a sheet
or film of plastic or other artificial material.
Note: Different countries limit
the proportion or thickness of the plastic film in different
ways.
In the EU, Directive 94/11/EC
dated 23 March 1994 lays down that if the synthetic layer is
thicker than 0,15 mm but less than one third of the total thickness,
the composite must be defined as "coated leather".
|
|
Plasticity
|
Ability of a solid material,
such as a finish film, to be deformed, bent or stretched, without
damage, and retaining the newly acquired shape.
|
|
Plasticiser
|
Finishing agent added to a finish
to increase the stretchiness and elasticity of the coat and
to render the film flexible during storage and use of the final
leather products.
|
|
Plastometer
|
Equipment to measure
the tendency of a leather to recover the initial shape and surface
after having been subjected to a deformation. Note: Test methods
IUP/21.
|
|
Plate (v); plating
|
Mechanical finishing process
used to subject the surface finish of a leather to a high pressure
from a heated, polished plate or cylinder to obtain desired
smoothness, flow-out, gloss and film formation.
|
|
Plated
|
Finished leather which has received
high-gloss, smoothness or film formation by using a plating
machine.
|
|
Plating marks
|
Marks
left by the plating machine either as join marks or edge marks.
Edge marks can be caused by the leather being in the incorrect
condition when presented to the plating machine.
|
|
Plating press
|
Mechanical or hydraulic press
where the leather is pressed to a heated smooth, polished steel
plate.
|
|
Plump
|
Describes a hide or skin which
is resistant to compression because the fibres have become distended
by water under the influence of osmotic forces.
|
|
Plump (v); plumping
|
To become resistant to compression
through distension of the fibres by water.
|
|
Plumping (swelling) tannage
|
Tanning process designed to tan
pelt in a plump, or swollen, condition.
|
|
Plumping force, (swelling)
|
Osmotic, or other force, tending
to cause collagen fibres or hide to plump or swell in an aqueous
solution.
|
|
Plumpness
|
See: Plump.
|
|
Plush (v); plushing
|
Subjection of the grain surface
of leather to the action of a rotating, plush-covered cylinder,
or wheel, to give it a gloss. Sometimes a sheepskin covered
wheel used for removing dust from the nap raising process for
suedes.
|
|
Plush pad
|
Plush-covered pad for applying
a liquid or solution evenly over the surface of leather by hand.
|
|
Pocket - (Axillae)
|
Part of
the hide or skin which covered the hollow between the body of
the animal and each limb and which, in the flayed skin, forms
a loose zone between the belly area and the fore and hind shank.
|
|
Pod, (seed)
|
Longish fruit of certain plants,
consisting of a case containing seeds. Note: Algarobilla, bablah,
divi-divi, cascalote, teri.
|
|
Poisoned
|
Dried hides treated with an aqueous
solution (0,2% to 0,3%) of arsenous oxide (dissolved with an
equal weight of sodium carbonate) to prevent insect attack.
After ‘poisoning’ the hides have to be dried again.
|
|
Pole dried
|
Air drying method by hanging
the leather lengthways over a pole.
|
|
Pole dryer
|
Drying unit in which the leather
hangs lengthways over a pole.
|
|
Polish (v); polishing
|
Polishing of leather by means
of special polishing machines with a rotating plush covered
wheel or cylinder. Stone cylinders, such as agate, are also
used, heated by the contact pressure, which give the leather
a glossy effect.
|
|
Polishing agent
|
Finishing auxiliaries containing
mainly modified synthetic wax or oil emulsions to achieve a
smooth, glossy surface of the leather, or used as a polishing
ground for aniline or pull up finishes.
|
|
Polishing wheel
|
A plush-covered, rotating wheel
for polishing the grain of finished leathers.
|
|
Pollution load
|
Quantity of emitted pollution.
The parameters used to specify this pollution may be BOD5, COD,
etc.
See: Biochemical Oxygen Demand
(BOD); Chemical Oxygen Demand (COD).
|
|
Polyacid tannage
|
Tannage with the iso- or hetero-polyacids
of tungsten, molybdenum, vanadium or silicon.
|
|
Polyacrylates
|
General term for polymerisation
products of the different acrylic acid esters and also copolymers,
occasionally with methacrylic acid esters, as well as some monomers
bearing amide groups.
|
|
Polyamide lacquer
|
Used as top coating agents either
alone or together with nitro-cellulose lacquers. Copolymers
which have obtained additional condensation with dicarboxylic
acids and diamines to be soluble in mixtures of alcohols and
hydrocarbons.
|
|
Polyaromatic tannin
|
Tannin agent whose molecule is
composed of several joined aromatic nuclei; the term includes
the hydrolysable and condensed vegetable tannins, as well as
most artificial tannins.
|
|
Polyazo dyestuff
|
Dyestuff which contains several
azo groups (-N=N-).
|
|
Polybutadienes
|
Film-forming polymer dispersions
used as thermoplastic binders in finishing preparations.
|
|
Polydisperse emulsion
|
Emulsion which has particles
in a wide range of sizes.
|
|
Polymer binder
|
Most important group of binders
mainly used as polymer dispersions in finishing. Film-forming
as well as other finishing properties depend on the monomers
used, the degree of polymerisation and the varying components
during copolymerisation.
|
|
Polymer dispersion
|
Polymer binder preparation offered
by chemical suppliers as ready-to-use dispersion with a solids
concentration of 30% to 60%.
|
|
Polymerisation tannage
|
Process of tannage involving
the introduction of monomers, or low molecular weight polymers,
into the pelt where they are polymerised to macro-molecules
which are not necessarily combined with the collagen, such as
tannage by glyoxal or dialdehyde starch.
|
|
Polynuclear complex
|
Complex ion containing several
central atoms, with ligands, bound to each other by linking
groups, such as o, oxo, etc. groups.
|
|
Polyphosphate tannage
|
Process of tanning involving
treatment with sodium polyphosphate in acid solution.
|
|
Polyurethane dispersion
|
Polyurethane binder preparation
offered by chemical suppliers as water soluble one-component
polyurethane dispersion. Modern top coating agents, used as
well in combinations with polyacrylates, polyesters and other
thermoplasts.
|
|
Polyurethane finish
|
Finish type using highly polymerised
addition compounds on the basis of polyether or polyester polyols.
The binder preparations are dissolved in organic solvents as
reactive/non-reactive products or dispersed in water in crosslinking
or non-crosslinking form.
|
|
Polyurethane lacquer
|
Finishing agents used in pigment
preparations and as top coats. The products are highly polymerised
polyaddition compounds of polyether or polyester polyols and
of aromatic or aliphatic polyisocyanates. To be divided into
reactive and non-reactive polyurethane systems. The reactive
systems have to be subdivided into two-component and one-component
systems.
|
|
Polyurethanes (PU)
|
Polyurethanes are products of
an addition of disocyanates to polymeric bivalent alcohols.
They are used in finishing of leather as thermoplastic and crosslinking
binders. Many combinations with polyacrylates, polyesters and
other thermoplasts are used depending on the desired properties
of the finish coats.
|
|
Polyvinyl chloride (PVC)
|
Polymer substance.
|
|
Pony skin
|
Leather traditionally made as a hair on product from pony
skins
but now a hair on fashion leather made from either bovine
or
equine raw materials.
|
|
Pore-filling
|
Ability to fill the pores in
a material such as leather.
|
|
Poromeric
|
Synthetic upper material, imitating
leather, having a microporous structure, giving it water vapour
permeability.
|
|
Post mortem
|
1. Post mortem
1a. After death
1b. Taking place, formed or done after death
1c. An autopsy to determine what caused the death
2. Postmortem: of or relating to the period
after death
(postmortem changes).
3. Post mortal: concerning death.
Note: the changes in
the cadaver.
Post mortem, postmortem, post
mortal; are of fundamental importance for the taxidermist, hide
curer, tanner.
|
|
Potlife
|
Maximum storage time of a certain
finish preparation. If the prepared solutions are not processed
within this potlife they may loose their desired film-forming
or finish properties.
|
|
Pouring head
|
Head of a curtain coating machine
regulating the flow of a liquid finish onto the leather.
|
|
Pre-flesh (v); prefleshing
|
Removal of more or less of the
subcutaneous tissues, or flesh layer, at an early stage.
Note: After soaking, rather than
after liming.
|
|
Preliminary tannage
|
See: Pretannage.
|
|
Premetallised dyestuff
|
Type of anionic dyestuff which
contains 1:1 or 1:2 metal complexes with metal atoms (Fe, Cr,
Cu).
|
|
Preservative
|
Chemical used to prevent microbiological
action.
|
|
Preservative pickle
|
Pickle liquor having a composition
specially adjusted to ensure preservation of the pelts treated
with it.
|
|
Preserve (v); preserving
|
To treat something in such a
way as to protect it against harmful influences.
Note: To dry or salt hides.
|
|
Pre-soak
|
Initial washing process in order
to remove dirt, dung, etc., from the hides or skins.
|
|
Pretannage
|
Incomplete and more or less superficial
tannage of pelt with some special tanning agent before the main
tannage in order to facilitate this.
Note: Aldehyde pretannage.
|
|
Pre-treatment
|
First stage in the treatment
process consisting of removing coarse solids, sand, gravel and
floating matter from wastewater.
See: Sand/grit removal.
|
|
Primary colour
|
One of the three colours, red,
blue and yellow, from which all other colours in leather dyeing
can be obtained by mixture.
|
|
Print (v); printing
|
Applying transfer prints to a
leather surface.
See: Emboss (v); embossing.
|
|
Print retention
|
Ability
of the grain of the leather to retain a print pattern that has
been applied by means of pressure from an engraved plate or
roller.
|
|
Printed grain
|
Artificial or simulated pattern
on the grain of the leather obtained by hydraulic plating press
or cylinder plating machines, using steel plates or rollers
engraved with a desired grain pattern instead of the ironing
plate or roller.
|
|
Printed leather
|
Leather bearing a surface pattern
produced usually by embossing, but sometimes by other methods.
See: Embossed leather.
|
|
Protease
|
Enzyme that degrades proteins.
|
|
Protected leather
|
Leather in which certain special
chemicals have been incorporated to render it less liable to
deteriorate through exposure to polluted atmospheres.
Note: The treatment is often
applied to vegetable tanned upholstery and bookbinding leather.
See: Impregnated leather.
|
|
Protective lacquer
|
Finishing agent used in top coats
applied in the finishing process to protect the leather surface
from soil, moisture and damage caused by impacts and scratching.
|
|
Protective layer
|
Top coat layer to protect the
leather surface.
|
|
Protein
|
Member of a class of high-molecular
weight, soluble or insoluble, nitrogenous compounds forming
the main constituents of protoplasm and of animal tissues and
composed of various amino acids, joined by peptide links into
one or more inter linked polypeptide chains. Sometimes this
complex is linked to a prosthetic group.
|
|
Protein binder
|
Agents, such as blood albumen,
egg albumen or casein, used in top coats.
|
|
Protein meal
|
Protein supplement used in feedingstuffs
for livestock. Usually produced by converting packing house
(abattoir) waste and livestock carcasses.
See: Bovine Spongiform Encephalopathy
(BSE)
|
|
Proteolysis
|
Break down of protein by enzyme
action.
|
|
PU
|
See: Polyurethanes.
|
|
Pull (v); pulling
|
Pull off the wool from sweated,
or painted, sheepskins.
|
|
Pull up effect
|
Leather has a greasy feel and
shows the pull up effect which means that on stretching the
former dark surface becomes lighter and shows more details of
the grain structure. This is usually achieved by the application
of a special oil/grease.
|
|
Pulled wool
|
Wool removed from a sheepskin
by a fellmongering process.
|
|
Puller
|
Something
for pulling with or something which has to be pulled, such as
a cord or the slide of a zip-fastener.
|
|
Pulped hair
|
Hair removed from hides and skins
in the hair-pulping process.
|
|
Pulping
|
Reduction of the hair on hides
or skins to a mass of fine particles, or pulp, which can be
subsequently washed away.
|
|
Pure colour
|
Colour composed of monochromatic
light, not mixed.
|
|
Pure dressed
|
Leather which has been dressed
after tanning solely by the introduction of grease, this being
achieved by hand application of dubbin.
|
|
Purple heat
|
Purple
colouration found on the flesh side of salted hides after storage.
Caused by salt tolerant organisms that produce a purple pigment
wax that is a type of quinone. This purple colour is destroyed
by acid.
Note: Pickling.
|
|
Putrefaction
|
Hides
and skins damaged and rendered evil-smelling by bacterial damage.
See: Bacterial damage.
|
|
PVC
|
See: Polyvinyl chloride.
|
|
PVC : EC Permanent Veterinary Commission
|
EC Permanent Veterinary Commission.
|
|
Pyrethrum
|
Naturally occurring contact insecticide.
Synthetic pyrethrins have also been developed.
|
|
Pyrocatechol
|
o-dihidroxybenzene, C6H4(OH)2.
|
|
Pyrogallol tannin
|
Tannin presumed to contain a
pyrogallol nucleus because it gives a blue colour with a ferric
salt or yields fragments with a pyrogallol nucleus on alkaline
fusion.
|
|
Pyrolysis
|
Thermal treatment of a material
(generally solid waste) producing gas, coke and unburned residues
under low concentration of oxygen.
|
