This subject is designed for students who will be involved in development of coatings in their daily professional life. This involves the chemistry, raw materials, formulations and applications of various resins which are important component of the coatings.
1. Fundamentals of film formers, monomers, functionality and its determination, degree of polymerization, molecular weight, Convertible and non-convertible film former – linear, branched and cross linked film former, natural and synthetic film former, homopolymers and copolymers. (12 hrs)
2. Classification and properties of natural resins, processing of natural resins like copal congo etc. Rosin sources, oleoresin and its composition. Recovery of resin and turpentine from oleoresin, properties and deficiencies of rosin film, modification of rosin-calcium rosinate, zinc and polymerized rosin, maleopimaric acid from rosin etc. Identification of rosin, Shellac origin, extraction of lac, Different kinds of lac and their properties, Composition of Lac, Chemical modification of shellac for use in coatings, French polish, leather finishes, oleo resinous varnishes etc. from shellac. (12 hrs)
3 Bitumen, pitches, gums and glues, natural bitumens like gilsonite and petroleum in Bit Pitches, general properties and uses of gums and glues. Cellulose; source, properties, modification of cellulose for use in surface coatings like cellulose esters, ethers, water soluble cellulose derivatives, their properties, testing and uses in lacquers, putties etc. Rubber resins sources of natural rubber, properties and modification of rubber like chlorinated rubber, cyclised rubber or isomerised rubber, their properties and uses. (12 hrs)
4. Alkyd resins, raw materials, chemistry and formulation of various alkyds, Carothers equation and its application, alkyd constant, manufacturing processes, classification, properties and application of various type of alkyd, modification of alkyds such as copolymerized alkyds, natural and synthetic resin modified alkyds, water soluble alkyds. Polyester resin-saturated polyesters components and formulation of unsaturated polyester resin, curing mechanism. Properties and application of polyester resin, water soluble polyesters. Phenolic Resins, classification, types of phenols used, reaction of phenol and formaldehyde, novolacs and cresol resin production, properties and application of various phenolics, water soluble phenolics. (14 hrs)
5. Polyurethanes: Chemistry of PU coatings, raw materials; Isocynates, monomeric isocynats, polyisocynats, blocked isocynates, Polyols (polyster polyols, polyether polyols and hydroxy terminated polyols), one component and two component coatings.
LIST OF PRACTICALS
1. To test softening point of natural resins
2. To determine acid value of natural resins
3. To prepare limed rosin and test the acid value
4. To prepare ester gum and test the acid value and softening point
5. To prepare penta ester gum and test the acid value and softening point
6. To prepare long oil alkyd resin and test the acid value
As the subject is completely theoretical, it involves synthesis of various resins used in paint industry. It can be made more interactive by showing various paint samples (automotive, wall coatings, high duty coatings etc). so that students can appreciate different types of resins and their properties.