Glues and adhesives: historical notes
Adhesives e stickers, commonly called glues are all those substances that put between two surfaces allow one anchor durable or a link.
More in detail for adhesives ed stickers we mean those types of substances that are so tough that the detachment between the two surfaces can only occur due to an internal molecular failure of one of the two bonded materials and not between the adhering surfaces.
The glues are divided into due large groups based on their origin:
- the colle, namely those of animal and vegetable origin;
- the stickers of synthetic origin.
The materials for gluing originate in prehistory. Bituminous materials were used to fix the points of spears and arrows even if in reality the evolution anticipated science by a lot; just think of the tongues of some frogs or carnivorous plants.
In ancient Egypt there are already materials to secure small pieces of cloth to the wounds, practically the ancestors of the patches.
The patent of the glue however it dates back to 1750 in England. The first glue was based on fish but later new patents were quickly filed using natural rubber, animal bones, starch and milk proteins.
For the colle synthetic we will have to wait until the beginning of 1942.
Discovered in the middle of World War II, it was currently discarded because it was considered too sticky. It was then rediscovered by two doctors, Coover and Joyner who were researching a heat-resistant acrylate polymer for aeronautical applications.
Joyner, rolling out a film, actually realized that the cyanoacrylate was a useful product and in 1958 the Eastman No. 910 was marketed as supercolla.
Application of glues and adhesives
There are so many products on the market. To avoid confusion, here are two practical tables to understand When use one product over another.
Glues of animal and vegetable origin:
|Bone or carpenter glue||Crafts for wood|
|Gelatine||Food use, thickener|
|Albums||Used as a thickener for paints|
|Casein glue||Use in the furniture industry|
|Cellulosic glue||Wallpaper binders|
|Starch||Preparation of tempera and wallpaper glues|
|Rubber based adhesives||Used for certain mechanical behaviors|
|Vinavil or vinyl glue||furniture industry, wood, do-it-yourself|
|Acrylic adhesives||Paper, glass, metals, fabrics|
|Epoxy adhesives||Industrial use for most metals|
|Neoprene stickers||Rubber and elastic plastics|
|Phenol-nitrile based adhesives||Metallic structural bonds|
It is clear from the two tables that the you use of glues and glues are among the most disparate and even used in the food industry or for the creation of artistic works.
Types of adhesives for wood
Obviously, the field will have to be restricted to construction and housework.
Therefore, only some types of adhesives will be investigated.
There are various types such as vinyl glue, known under the trade name of Vinavil, EVA glue and PUR glue.
Vinavil or vinyl glue
Widely used in the sector of wood he was born in mobile, the vinyl glue is extremely economic and not dangerous for health. It is in fact very often used also in schools for small crafts by children.
It is extremely suitable for use with wood because penetrates extremely thoroughly in the fibre making the anchor even more resistant than the intact piece.
This glue can also be used to bond materials such as paper or leather, but one of the two surfaces must be porous e absorbent.
Vinyl glue is not very water resistant. In fact, in the presence of it, it tends to become soft again.
However, there are details resins to be added before use which will make the anchors resistant even to humidity. Another problem is yours poor resistance at high temperatures and consistency rubbery makes it difficult to sand.
Its name is the acronym of Etil Vinil Acetato and it is a glue used a lot in the wood sector such as hot melt adhesive.
This type of glue is used especially for the covering of profiles for the edge of the panels or in the frames. Commercially this glue is simply called glue hot melt, even if on the market now this wording is decidedly ambiguous because even the PUR glue is effectively thermo fusible.
It is sold industrially in the form of flakes or small balls.
It is applied by means of op rollers by spreading at a variable temperature between 180 ° and 220 ° C.
The EVA glue however it is also used in the sector of do it yourself. In this case, it is used with pistol electric decidedly more practical, which dissolve the glue via a heated nozzle.
In this specific case, the adhesive works without solvents, therefore, it does not require drying times and will also adhere to non-absorbent surfaces.
The rough line it is not toxic but at high temperatures it could decompose releasing acetic acid, causing unpleasant odors.
The trouble main of this type of glue is found for its scarce viscosity especially at high and medium temperatures.
In fact, it melts at 150 ° C but already around 70 ° C it loses a lot in adhesion.
It could therefore happen that products treated with this type of glue can suffer damage in summer, if stored in very hot environments, such as a container, or if exposed to direct sunlight.
This product belongs to the family of polyurethane adhesives, both hot and cold. It is ideal for many types of applications thanks to them resistance e tenacity. These types of glue are activated both in the presence of catalysts and humidity.
Her main feature and the resistance very strong to solvents and water that it acquires once hardened.
Furthermore, certain reactions lead to a production of carbon dioxide which it will produce foam to glue. This makes it suitable for the production of so-called foams, including the expanded polyurethane
In the wood sector they are used essentially two kinds of PUR glues:
- a cold: they are usually found diluted in solvents, and in the furniture industry they usually replace vinyl glue because they have a better seal at high temperatures and in the presence of humidity.
- hot melts O hotmelt: they are usually mixtures not yet activated and are mainly used in the plating of profiles and panels of MDF or chipboard.
Their appearance is completely identical to EVA glues but they melt at decidedly lower temperatures. Once hardened, the polyurethane molecules no longer melt and will perfectly resist water and solvents. They have a smooth and slightly porous surface.
How to glue metals
A completely different matter when working with i metals. Choosing the right product in this case is essential and it is possible to evaluate three types of different adhesives:
- polyurethane glues;
- epoxy glues;
- super glue;
Epoxy glues for metals
We are talking about products with very high performance. The polyurethane glues they are also used in carpentry, joinery and even in the creation of jewelry.
The features of these adhesives are very varied depending on the type of product. They can in fact be rigid or flexible, opaque or transparent or with different setting times. However, they have in common thevery high resistance to heat and chemicals.
Usually, the best products for bonding metals are the two-component glues or formed by a resin epoxy it’s a catalyst, o indurente.
The two parts, when combined, create an extremely strong and lasting bond that makes them effective both for construction work and for simple repairs.
This type of glue is practically used only for working with metals.
They have a very high resistance both att‘water that ai UV rays.
They have a time of drying very fast but in the process they do not become brittle.
Between advantages that present once hardened, it is noted that they may be smooth, painted or colored. These characteristics make this type of glue extremely suitable for works in home including the finishing of the furniture, the sealing grouting or repairing floors.
Given its very high resistance to high temperatures it is also suitable for outdoor works. It can also be used with other types of materials such as natural stone, rubber, wood and ceramic.
The super glue
With a decidedly evocative name, these industrial adhesives are perfect for almost all repairs. They have practically no limits and besides metal they will be able to anchor practically anything: wood, fabrics, ceramics and plastic.
Used extensively for repairing parts of cars or objects of ceramic like plates and cups. Using these adhesives is very simple, but you just have to be careful to clean very accurately surfaces to be glued from any fragments or foreign particles before application.
When using this super glue though it will be fine protect yourself with gods gloves latex or nitrile. Avoid those made of PVC, nylon or cotton.
The super glue, once in contact with the skin, if not removed immediately, will create many headaches!
Source: LAVORINCASA.it by www.lavorincasa.it.
*The article has been translated based on the content of LAVORINCASA.it by www.lavorincasa.it. If there is any problem regarding the content, copyright, please leave a report below the article. We will try to process as quickly as possible to protect the rights of the author. Thank you very much!
*We just want readers to access information more quickly and easily with other multilingual content, instead of information only available in a certain language.
*We always respect the copyright of the content of the author and always include the original link of the source article.If the author disagrees, just leave the report below the article, the article will be edited or deleted at the request of the author. Thanks very much! Best regards!