What is Paint?

Paints & Varnishes are products of Surface Coating Industry are also called as Decorative & Protective coatings. They are used :-
i) For Protection of structural material on exposure to serve climatic conditions.
ii) For Decoration & aesthetic appeal.
iii) For Sanitation with influence at science in the modem age.

A Paint is designed to protect & decorate the substrate on which it is applied. In general paint comprise dispersions of solid or liquid particles in a liquid medium. The one exception is powder coating in which the material is solid & is melted in the application process. Paint is a complex mixture. It contains Binder, Pigment Solvent & Additives. It can be defined as the dispersions of pigment in a suitable binder & when applied in the form of a thin film (layer) by suitable method of application driers, there by giving solid, adherent, tough opaque & cohesive film. 

The functions of the major ingredients can be summarized as follows :

Pigment

The insoluble dispersed particles in a paint which give dried film its characteristic properties, colour, hiding powder & resistance to light, heat, water, chemicals & corrosion.

Binder

The non-volatile portion of the vehicle of a paint, it binds, or cements the pigment particles together; & the paint film as a whole to the material to which it is applied. In modern paints the mechanical & resistance properties of the film are contributed very largely by the binder. This is the heart of the paint depends on its performance. In addition to its weathering & wearing properties; it imparts the other important properties of adhesion, gloss, drying, impermeability & resistance to chemical etc.

Solvent/Thinner

Liquids, usually volatile, which are used in the manufacture of paints to dissolve or disperse the film forming constituents, & which evaporate during drying therefore do not become a part of the dried film. They are used to control the consistency & character of the finish & to regulate application properties.

Additives

In addition to the major components, paint may contain small quantities of driers, anti-skinning & antisettling agents, fungicides or bactericides & any surface-active agents used to assists dispersion of the pigment.