Lecture 11, paint
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This document discusses paints used in construction, including their components and uses. It describes the typical materials that make up paint bases, fillers, binders, solvents, driers, and pigments. It outlines the main functions of paint to protect surfaces, improve appearance, and make materials durable. Several types of paint are summarized for different surfaces, including distemper and emulsion paints for interiors, cement and acrylic paints for exteriors, varnishes and polyurethanes for wood, and enamel paints for metal. The document also briefly mentions the paint industry in Bangladesh.
Lecture 11, paint
- 1. A tale of ‘Paint’ Presented by Dr. H.M.A.Mahzuz
- 2. Paints: Paints are used to protect metals, timber or plastered surfaces, brick work and concrete work from the corrosive effects of weather, heat, moisture or gases etc and to improve their appearance. Composition of the paints can be easily adjusted in the process of their manufacture, depending upon the purpose for which they are required and quality of the work required.
- 3. Basic Components of Paint Paints are prepared by mixing the various ingredients in well-balanced proportion. Paint is generally made up of following main components:
- 4. 01. Base:- • Base is a solid substance in a fine state that forms the body of paint. It forms the bulk of paint. It conveys the character of the paint. Base usually consists of white lead, red lead, zinc oxide (zinc white), iron oxide, titanium white, aluminium powder, lithophone. The main function of all this materials is to make film of the paint, opaque, harder, and elastic & prevent formation of shrinkage cracks.
- 5. 02. Inert Filler or Extender:- • It is cheap pigment added in a paint to make it more economical. The main function of filler is to modify the weight of paint & makes it more durable. Inert fillers are used to impart various physical properties other than colour, i.e. opacity or texture, or simply to make the handling of paint better. • The commonly used inert fillers or extenders are barites (barium sulphate), lithophone, silica, silicate of magnesia or alumina, whiting, gypsum, charcoal, etc…
- 6. 03. Vehicle or Binder:- • It is also known as binder. It is oil to which the base is mixed. It is the liquid substance which holds the paint together & also binds it to the surface that is to be painted. It simply means it provides the durability, toughness & water proofness to the paint. It also helps to spread the paint ingredients uniformly over the surface to be painted.
- 7. 04. Solvent or Thinner:- • It is the oil that can make the paint thin and increase the spread and are also known as thinner. Solvent make the paint workable and gets evaporate during drying of the paint film. Solvents are a usually volatile substance which provides properties such as smoothness, easy flow and brushability.
- 8. 05. Drier:- • The function of drier is to accelerate the process of drying. A drier absorbs oxygen from the air and transfer it to the vehicle (linseed oil) in the paint film, which in turns get hardened. It may be either in the form of soluble or paste state.
- 9. 06. Colouring Pigment:- • Colouring pigments are used to hide the surface imperfections. They are colouring materials added to the paint to impart the desired shade & colour. They protect the paint film by reflecting the ultra violet light. They also improve the impermeability.
- 10. USES OF PAINTS: The main functions performed by paints are: • It is used to give a high-class finish, • It is used to give attractive colours, • It is used to give pleasing surfaces design and appearance, • It is also used to protect the material from atmospheric effects, • To protect various substances from corrosion, • To protect wooden articles from wet-rot and many other types of defects, • To make the materials long lasting.
- 11. PROPERTIES OF GOOD PAINTS : The main properties of a good paint are as follows: • It should give a thin and uniform coating. • It should be hard and durable on drying. • The painted surface should not crack on drying. • It should be resistant to weathering and corrosive action. • It should be water-repellent (except water paints). • It should have good spread. • It should have good adhesive power. It should give a good finish with attractive colour, design and appearance. • The colours should be fast and permanent. • It should be cheap and economical.
- 12. Types of Paints Used in Building Construction • There are many purposes for using paint in building construction. These includes increase the visual appeal of building surface, protect surface against weathering impact, make the surface water proof, protect surface from termite attack and increase the surface durability. In building, you will find four types of places to paint on. Such as – 1. Interior wall and ceiling 2. Exterior wall surface 3. Wooden surface and 4. Metal
- 14. 1. Interior wall and ceiling • To increase the visual appeal and smoothness of wall surface and ceiling interior paint is done. Following types of paints can be used as interior paint - Distemper: Distemper is common type paint used in interior wall and ceiling for protecting and decorating brick wall, concrete and plastered surface. Variety of distemper are available in the market. Such as acrylic distemper, synthetic distemper, dry distemper etc. Acrylic distemper is washable and can be applied on plaster, wall and asbestos. Synthetic and dry distemper are not washable. Plastic paint: It is also called plastic emulsion paint or interior emulsion paint. It is water base paint. This paint is durable and can be washed. They are available in three categories - Regular emulsion Economy emulsion and Premium emulsion
- 15. 2. Exterior • Exterior paint must have weather resisting capability. It can be oil based or water based. But oil based paint is not generally recommended for exterior painting. Following types of exterior paint are available in market - Cement paint- It is water based paint. It gives nice finish to newly constructed building. Acrylic emulsion- It has high capability to withstand against weathering impact. It gives surface a nice and durable finish. Textured plaster- It is also emulsion based paint. But the surface protection capability of textured plaster is much better than other emulsion paint.
- 16. Cement paint Acrylic emulsion Textured plaster
- 17. 3. Wood • Traditional paint for wood is varnish. But now a days many people choose modern version of varnish "polyurethane and melamine" for wood finishes. It allows wood grains to see through it unlike varnish.
- 18. 4. Metal • Enamel paint is commonly used for metal. This is oil based paint. Following types of enamel paints is used on metal surface in building construction - a) General purpose enamel paint b) Synthetic enamel paint c) Premium enamel paint a) General purpose enamel paint - This type of enamel paint's protecting capability is lower than other two. But using two coat of this paint can give long protection to metal surface. b) Synthetic enamel paint - This type of paint gives metal surface a good finish with atmospheric protection. Synthetic enamel paint can also be used on wooden surface. c) Premium enamel paint - It has excellent protective capability against atmospheric attack on metal. It also gives glossy effect with nice surface finish. There are also some other places in building construction where special painting is needed. Such as water proofing paint, anti-termite paint etc.
- 19. Paint Industry in Bangladesh • Berger Paints Bangladesh Ltd-Bangladesh • Elite Paint and Chemical Industries-Bangladesh • Romana Paint • RAK paints • Royal paints • Asia paints • AQUA paints • Ujala Paints • Alka Bangladesh Pvt Ltd(Alka Group Pakistan)- Bangladesh • Akhmanu Enterprise
- 22. Safety us an important issue-
- 23. • Thanks