Advanced Level Finishing Course / Module 3

ADVANCED LEVEL FINISHING / MODULE 3

LEARNING OBJECTIVES

Students need to fully grasp the concepts covered on the Intermediate Level Finishing Course.

In addition to the Intermediate Level Finishing curriculum, the following are covered in this module:

Influence of wet end operations on leather finishing

Buffing and de-dusting of crust leather before finishing

The correct process sequences in the finishing of leather

Film formation process

The means of covering defects (pigment vs dyes)

Solar reflective pigments

Colour theory and measurement / CIELAB

Reasons for finishing

Different finish coats

Chemicals used in finishing and possible substitutes

Building blocks of a leather finish

Choosing the correct basecoat resins

Crosslinker chemistry

Water-based vs solvent-based finishing

Advances in water based polymers

Compact finishing products

Film flow and thixotrophy

Solvent surface tension and contact angles

Adhesion and penetration: the influence of contact angle, leather hydrophobicity, dust

Finish machinery: roller coater, curtain coater, spray lines (HVLP, air-assisted, airless air-assisted), electrostatic spraying, powder coating

Modification of spray equipment to reduce waste

Impregnation to improve selection

Upgrading defects

Acrylics and penetration theory

Corium minor vs corium major junction

Importance of buffing / dedusting

Foam finishing

Micro-sphere technology

Cationic finishing products

Controlling the variables in the finishing process

Ecological demands in finishing

Prevention of dye migration

Finish formulations for various leather types

Importance of correct film: non-film forming ratios

Choice of different finishing chemicals for different leather types

Finishing waterproof leathers

Water-borne transfer systems

Finishing patent leathers

Anti-finish concept

Full grain versus corrected grain

Aniline versus semi-aniline versus pigmented finishes

Spraying

Hand-spraying

Gun setting

Spraying defects

Cross-coat theory

Viscosity / filtration of mix

Automatic spray-booth

Viscosity / filtration of mix

Conveyor speed

Rotary spray arm

Pumps

Electronic eyes

Water or extraction system

Drying tunnel heat / humidity control

Nozzles, air and mix lines

Roller coating

Conveyor speed

Doctor blade setting

Viscosity / filtration of mix

Groove depth and pattern

Direct vs reverse

Heated rollers

Roller speed

Roller gap

Roller cleanliness

Curtain coating

Conveyor speed

Pump flow

Weir cleanliness

Wind protection

Viscosity / filtration of mix

Padding

Viscosity / filtration of mix

Rate of absorption / drying speed

Plating / ironing

Temperature

Pressure

Drying of finish

Drying efficiently in the finishing department

Embossing

Influence of retannage

Groove depth

Temperature / pressure

Glass transition temperature

Polishing

Polishibility of the finish

Testing of leather finishes

Conditioning of samples

Finish adhesion

Rubfastness

Flame retardance

Taber

Flexibility

Lightfastness

Effect of leather care products on leather testing performance

Effect of finishing chemical particle size on finish test performance

Factors affecting the performance of water based topcoats

Effect on the finished leather of forces applied within leather finishing

Measurement of finished leather

Comparison of different types of measuring machines