Adhesives

Adhesives are used to stick two or more parts together so that they behave as a single unit. Adhesives are of three types viz., organic adhesives, synthetic adhesives and rubber-based adhesives.

1. Types of Adhesives

(i) Organic Adhesives

Organic adhesives are made from animal protein, blood albumen, milk casein or starch, etc.

(ii) Synthetic Adhesives

Synthetic adhesives are made from natural resins or from manufactured plastic resins such as melamine resins, urea resins and phenolic resins.

(iii) Rubber-based Adhesives

Rubber-based adhesives are materials in which rubber is dissolved in benzene or ground with other resins of plastics.

2. Uses of Adhesives

Adhesives are used for the following building construction works.

(i) Use in Timber Construction

In woodwork, formaldehyde adhesives of phenol, urea and resorcinol are the accepted products. They are also used in timber joints to strengthen the joints. Four types of adhesives used for timber construction are: Weatherproof and Boil proof (WBP), Boil resistant (BR), Moisture resistant (MR) and Interior (INT).

(ii) Use in Fixing of Ceramic Tiles

Adhesives used for fixing ceramic tiles provide greater bond strength, reduction in weight of fixing material and make the wood cleaner and quicker. Further use of adhesives eliminates the need to soak the tiles in water and errors due to variation of the composition of the mortar. Latex-based adhesives are very popular.

(iii) Use for Joining Concrete

In practice, there may be instances where concrete has to be joined with other concrete work or other materials. Epoxide adhesives are the best adhesives to be used for bonding broken concrete face, setting metal noses in stairs, etc. The required bond strength is attained in short duration of time.