Studies on Effect of Differnt Pigment and Binder Combinations on Surface Property of Finished Leather

Wakaso, Mishamo (2014) Studies on Effect of Differnt Pigment and Binder Combinations on Surface Property of Finished Leather. Masters thesis, Addis Ababa University.

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The present work attempts to analyze the surface and physical properties of leathers finished with various combinations of binders and pigments by keeping other auxiliaries constant. The contact angles of liquid drops resting on the leather surface have been used to evaluate surface energy, acidity, basicity components of the surface energy, polarity and work of adhesion. Contact angle values have been measured for chrome tanned and conventionally retanned crust and finished leather made by varying pigment and binder combinations. The wettability of finished leather has been correlated with the contact angle values: the higher the contact angle value the less wetting is observed. Complete wetting can be obtained when the contact angle value is zero i.e. the drop of liquid spread spontaneously on the surface and partial wetting is obtained when the contact angle value is in between 00 and 90o. Acrylic binders with different film forming properties, protein, polyurethane and butadiene binders have been combined to prepare different finish formulations. Pigment to binder ratio for acrylic system and acrylic with polyurethane binder system have been optimized from the information obtained from contact angle values which have direct relation to degree of wetting. And the results have been correlated with wet and dry rub fastness, finish adhesion, vamp flexing value, water vapour permeability and water proofness. It has been observed that when the surface of leather is coated with acrylic binder the contact angle value due to polar solvents(water) , non polar solvents(hexadecane) and moderately polar( DMSO) and methyl iodide show that as the thickness of coating increases, the contact angle value decreases for the base coat and sharply increases when top coat is applied. Top coats have the ability to increase the contact angle and they improve the performance properties of leather such as water resistance, fastness, finish adhesion etc. Cationic and anionic finishing formulations have been compared to study their effect in modifying the surface of finished leather based on contact angle values, wet and dry fastness to circular rubbing and water resistance. It has been observed that leathers finished using anionic finishing technique shows better wet rub fastness and water resistance effect compared to cationic finishing technique.

Item Type: Thesis (Masters)
Uncontrolled Keywords: contact angle, surface energy, cationic finishing, anionic finishing, work of adhesion, acidity, basicity
Subjects: Q Science > Q Science (General)
Q Science > QD Chemistry
T Technology > T Technology (General)
T Technology > TP Chemical technology
Divisions: Africana
Depositing User: Andriamparany Edilbert RANOARIVONY
Date Deposited: 30 Oct 2018 13:24
Last Modified: 30 Oct 2018 13:24

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