What will you do when a page of your book is
torn accidentally? It can be fixed by using a cello tape. How cello tape works? There is a
paste like material in one surface of the cello tape. Have you ever discussed
about this material? The paste like substance is called adhesive. It is
commonly known as glue, mucilage, or paste. The substances applied to one
surface, or both the surfaces of two separate items that binds them together
and resists their separation are called adhesives.
Adhesives are substances that are used to join
two or more components together through attractive forces acting across the
A practical experience
Do you notice how puncture of your bicycle is
repaired by the shop keeper? He ensures the punctured surfaces are clean, dry
and free of dust, and roughens the area around the hole using a metal scraper.
He takes an appropriate patch of tyre-tube and applies a suitable adhesive to
both the roughened area and to the underside of the patch, apply firm pressure
and allows drying completely. Why does he apply pressure? This increases the
adhesive capacity at both the surfaces and ensures proper binding.
There are two kinds of adhesives, one is
natural made from starch and another one is artificial made from chemicals. The
one used in puncture shop is an artificial adhesive.
Artificial adhesives may be classified in a
variety of ways depending on their utilities. Their forms are paste, liquid,
film, pellets, tape.
It is used in various conditions such as hot
melt, reactive hot melt, thermo setting, pressure sensitive, and contact.