International School of Tanning Technology

MODULE 1 COURSE CURRICULUM

Skin Structure

The gross morphology, histology and the chemical make-up of all skin components
Detail on the hair, collagen, collagen-water, glycosaminoglycans and other inorganic and organic structures
Stress is placed on the development of the 1°, 2° , 3° and 4° structures of collagen and the consequent differentiation of structure into tissues
Knowledge of skin structure relative to processing

Skin Types / Defects

Modification of the tanning process to the skin type
Different animal skin types include cattle (calf and adult), pig, sheep (wool & hair sheep), goat, ostrich and reptile
Defects that occur in the natural animal (breed differences), living animals, slaughter preservation, storage, tannery processes
Causes and effect on preservation is covered

Preservation

Preparation of the hide / skin for preservation and problems associated with curing
Mechanisms of action of the various preservation methods
Monitoring and control
Bacterial decay and growth conditions

Beamhouse

Correct process sequences
Role of each process
Chemicals involved with each stage and possible substitutes
How each stage is monitored and controlled
The chemistry of collagen modification by preparative stages of tanning
The latest machinery developments, monitoring and controlling
Soaking
Reason for the process
Influences on soaking
Latest development to improve soaking
The role of enzymes
Soaking problems
Unhairing / Liming / Reliming
Unhairing / Liming / Reliming
Chemistry of disulphide bridge cleavage, modification of collagen, lanthionine formation and osmotic swelling
Latest developments to improve quality
Influences on the processes
Reasons for the process
Unhairing / Liming / Reliming
Deliming / Bating
Ammonium salt deliming process
Chemistry of calcium hydroxide and sodium hydroxide alkalinity
Latest developments to improve quality
How the deliming / bating process is influenced
Enzyme activity
Pickling
Reason tor the process
Preparation of the hide / skin for the penetration of chrome
Removal of glycosaminoglycans and splitting of fibre bundles
Pickling chemicals
Latest developments to improve quality
Physical chemistry of electrostatic swelling and its prevention
Salt-free pickling
Bleaching
The mechanism of pigment breakdown
Bleaching agents and their formation in a CIO2 acid environment
Removal of noxious gases and excess bleaching agents

Tanyard

The correct process sequence
The role of each stage
The chemistry involved with each stage and possible chemical substitutes
Tanning
Reason for the process
Factors that affect penetration & fixation of chrome
Hydrolysis of chrome salts
Chrome tanning mechanisms
Ionisation of amine groups for gluteraldehyde tannage
Mechanism of gluteraldehyde tanning
Ionisation of carboxyl and amine groups
Basification
Reason for the process
Chemicals used
Schorlemmers basicity
Role of pH in tanning processes
Consequences of loose tanning agents
Olation and oxalation

Testing

Shrinkage temperature
Boil test
Calamari test
Chrome content of effluent / leather
pH measurement of liquor and the skin
Density
Temperature
Speed

Machines

Sammying
Shaving
Splitting lime/ blue
Fleshing
Drums / paddles / hide processors
Beams and fleshing knives
Raceways