Paint technology — properties and uses of resins Which of the following statements about resins used in paints and varnishes is/are correct?

Introduction / Context:Resins are fundamental binders in coatings. Their solubility, film-forming characteristics, and interaction with solvents dictate the protection and appearance of architectural and industrial finishes. Exam items often check basic facts about solubility and function.

Given Data / Assumptions:

• Conventional natural and synthetic resins are considered (e.g., rosin, alkyds, phenolics).
• Spirit denotes alcohol or compatible organic solvent systems.
• Varnish is a solution of resins in a suitable solvent, forming a clear film.

Concept / Approach:Resins, being organic polymeric materials, are generally hydrophobic and thus not water-soluble. They dissolve in organic solvents, enabling application. In varnishes, resin constitutes the main film-former; upon solvent evaporation, the resinous binder remains, providing gloss, hardness, and protection.

Step-by-Step Solution:Check solubility: hydrophobic resin → not water soluble → correct.Check solvent behavior: many resins dissolve in spirits → correct.Confirm application: resins are central to varnish formulation → correct.Drying: solvent evaporates, leaving solid resin film → correct.

Verification / Alternative check:Coating datasheets list resin solids percentages and specify organic thinners, consistent with these statements.

Why Other Options Are Wrong:Each individual statement is true; the comprehensive choice is therefore the best answer.

Common Pitfalls:Confusing water-reducible emulsions with true water solubility of resins; many so-called water-based paints still rely on hydrophobic polymer particles dispersed in water.

Final Answer:All of the above.