A glue is a product which is used to agglutinate and achieve the accession of one object with another. What the glue does, therefore, is paste . For example: "I'm going to buy glue to fix the shoes", "The glue did not work: I could not join the pieces of the vessel", “If you don't want to make a hole in the wall, you will need a good glue to adhere the picture next to the window”.
The purpose of a glue is to get things together once their surfaces come into contact. This means that the objects in question they don't cross or assemble , but they are linked only thanks to the cap of glue.
Adhesives, on the other hand, may be intended for home use or have an industrial purpose. In the first case, you can mention the glue used by children in the school or the office workers to glue papers. The industrial glues , on the other hand, allow more solid joints, very difficult to break.
Among the components that allow the creation of glues, are rubber of natural origin, various polymers and even substances derived from dairy products, corn and potatoes (or potatoes ).
There is a wide variety of types of glue, some of which are set out below:
* wet : only applied on one of the parts that you want to paste, having previously fixed both in the position adequate. This type of glue acts as soon as the solvents evaporate (there are, on the other hand, the so-called glue solvent free, which have water as a substitute for them). For best results, it is recommended to use porous materials, since they favor the drying process;
* contact : Unlike the previous type of glue, it must be applied to the two parts that you want to glue. In order to achieve adhesion, strong pressure must be exerted and wait for the solvents to evaporate. Once this point has been reached, the effect is immediate, in addition to producing a Union resistant to loads in a short time;
* reagents : offered in versions of one or two components and act when a reaction which makes them harden, which can be physical, catalytic or chemical.
+ single component reagents : the reaction occurs with the oxygen in the air (aerobics), metal ions (anaerobes; it is used when the glue cannot come into contact with the air), the moisture present in the air or the UVA rays. This kind of glue should only be applied on one of the faces that wish to adhere and the reaction is instantaneous, once the second one acts component , which may be one of those mentioned above;
+ two component reagents : these do not depend on the environment, like the first ones, but are sold with two pasty components, powder or liquids that must be mixed in a given proportion and manipulate within the indicated time (what is known as useful life) since they begin to harden immediately. It is necessary to hold the parts until they have completely adhered. The time it takes for the process depends on the components and the conditions of the environment;
* hot melt : they are sold in the form of foil, powder, granulate, net, bar or cartridge. They generally do not require any extra steps (such as mixing) and do not contain solvents. To act, this type of glue must undergo high temperatures (from 110 ° C to 220 ° C, depending on the product) and can be applied with the help of a gun;
* self-adhesive : They maintain their permanent adhesion capacity and are used when a long lasting finish is not sought. Some of the ways in which they are marketed, such as single or double sided adhesive tape, are very popular in educational and business environments.