Since the invention of the first, still natural materials, adhesive technology has evolved much. However, the aim has not changed: two materials need to be stuck together. In this article, we will have a brief summary of the types of adhesive.

Basic classification of adhesives

Usually adhesives are liquid materials that need to be made suitable for the purpose of application before using them, that is to make them liquid as surfaces can be moistened only this way. Solidification takes places when solvents evaporate or during solidification processes. These are mainly the characteristics of one-component adhesives.

Based on their binding methods, adhesives can be divided into two categories. One group is comprised of adhesives binding without chemical reactions that do not actually bind, only moisten. These are cold-binding, permanently adhesive materials, and some of these create binding by drying, when solvents evaporate. Hot melt adhesives do not stick at room temperature, they do not moisten, so the adhesive needs to be melted first to create binding, the melt needs to be applied to the surface, and usually we need to apply clamping force. Bonding is created by the adhesive solidified in the binding.

The other group includes adhesives binding with a chemical reaction that can be further divided into two more categories based on the nature of reaction: polymerization and polycondensation adhesives. In the first case, the new binder is created by the continuous combination of the components, while in the second case, due to the pressure of the condensation by-product, the application of clamping pressure is always required in adhesive technology.

We started from here: adhesives of natural origin

This includes materials of flora and fauna. With the minor or major chemical transformation or physical modification of plant materials and of the sap of certain trees or materials extracted from fruits, vegetables and crops, adhesive materials can be produced. One of such most important materials is cellulose, the building material of plant cell wall. Starch, produced by biosynthesis in plants, is also very important. The paste, extracted from starch by wet cooking, can be used as glue.

From adhesives of animal origin, it is worth mentioning glues, like casein glue, which is one of the milk’s proteins. It is distributed in a powder form, which you can use by mixing with water, and it solidifies by evaporating water. One of the oldest adhesives known and used is animal glue, which is distributed in the forms of powder, granule, bead and slab. Its advantage is that during cooling, it instantly provides adequate initial adhesive strength.

Adhesives of mineral origin

Adhesives in this category can be organic, such as bitumen and inorganic, such as cement. It is good to know that despite their limited scope of use, they are of great importance, they are irreplaceable.

Adhesives made from glass melt were used for heat- and fire-resistant metal bonds. Ceramic adhesives can be used to create heat-resistant bonds more generally than glass. Phosphate cements are also of mineral origin and they are the basic materials of dental fillings, or lead oxides used to repair ceramic pipes, valves, stoneware goods, or hydraulic cements, such as gypsums. This latter – together with bitumen – is considered as the most important binder of architecture.

What about synthetic adhesives?

Synthetic adhesives produced by modern chemical industry started to replace traditional ones from the middle of the 20th century. Epoxy started its “career” in the 1950s, which was successful primarily due to its ease of use, excellent strength quality, and 100% content of dry matter.

There are a lot of types of synthetic adhesive. For example, the most important areas of use of polyamides are adhesives for upper making or mounting on shoe trees in the shoe industry, adhesives of metal-to-metal bonds in the automotive industry, structural wood adhesives in the timber-processing industry, but tools made from it also have an important role in the production of components for major appliances.

Polyurethanes are one-component solutions that are suitable to glue textiles, leather, wood and paper. Epoxy resins are usually comprised of two components that need to be mixed before use in the proportion specified by the manufacturer, which results in polymerization, that is the solidification of the adhesive. They can be used to glue various materials, such as metals, ceramics, porcelain or wood. (Two-component adhesives often have the fancy name of ‘power’, referring to the strong bond that can be created with these products.)

The solution of polymerization adhesives is primarily used to glue objects made from the same materials. Solvent polyacrylate adhesives can be used to glue some types of plastic – like polystyrene, PVC, polyethylene – wood, paper, leather and textile. Finally, we should not forget about polyacrylates: the best known of these are cyanoacrylates, which we know as superglue in everyday life, and their thicker gel type can be used also to fix glued surfaces. Among them, we can also find types created to firmly fix specific types of materials.

Of course, the world of adhesives has become enormous since the first materials. Today, in relation to this, we do not talk about adhesives only but also about a wide range of products that aid gluing: such as accelerators, adhesive applicators or sealants and filling materials. A separate category is also comprised of various adhesive tapes that make operations much more comfortable than it was for our ancestors using animal glue. In addition, it is possible to buy adhesives with good bond strength for almost all types of materials, and also there are several types of universal adhesives available in specialized stores.

 A brief introduction to 3M

Just like we boast the fact in our website: as the official business partner of 3M since the foundation of Flanker in 1998, we distribute industrial products of adhesive technology. But why is this an important data? We can give you a specific answer to this only if we show you what the 3M company and the products manufactured by them and distributed in Hungary by Flanker mean.

This unusual brand name is connected to the 32^nd member state of the United States. The M’s actually refer to the original name of the company founded in 1902. More than 100 years ago, the company, founded by five businessmen and initially engaged in mining, was incorporated as Minnesota Mining and Manufacturing Company. The longer name was later shortened to the clever and still used two characters of 3M.

By today, a confident group of companies known internationally has emerged from the modest beginning, which is considered to be an indispensable participant in the world of chemical brands. More than 60,000 products are comprised in the portfolio of 3M, and the company itself also serves individual customer- and business needs in several divisions. For ordinary customers not engaged in adhesive technology, the best-known product is perhaps the Post-It Note (of which you can find interesting facts here, in our website).

But it is worth taking a better look at 3M!

The headquarters of the American company is currently located in Maplewood. The products that can be used by customers in many areas, originally born in the form of patents, start their journey to conquer the world from here. For example, the health sector benefits from 3M products just like production, the automotive industry, the electronics industry or the business sector. Wherever we look, we can see 3M’s adhesive technology products and other solutions almost everywhere. (The 3,000 newly filed 3M patents every year ensure a great supply for product development.)

3M’s range can also be interpreted as a huge department store where you are taking a walk while you are looking for tools for general and special purposes. The various materials include everything from small to big that are related to safety, to industry, to transport, to electronics or to health care.

One of the priority areas also in Hungary is the world of occupational safety and protective equipment. Basically, 3M offers products to the protection of almost all vital organs of the human body, whether it is respiratory protection, hearing protection or welding protection. The industrial portfolio is also remarkably wide: for example, for those who work in a lot of industrial noise, the company offers earplugs of adjustable protection, but welding shields for the heavy industry are also part of the product range.

3M is the owner of many other known and important brands. For example, Scotch, which offers more than 400 types of adhesive tape, insulating adhesive and other products under the brand name of 3M and Scotch. It is interesting to note that the first transparent adhesive tape was invented by a 3M engineer, formerly a banjo player, Richard Drew in 1930. The specialist’s aim was to be able to create a moisture-free closing. The iconic product of Scotch is the distinctive “snail” tape dispenser, introduced in 1939. The first version was pressed from metal, while they started to produce the molded plastic version one year later. In 2013, they reinvented the “snail”, and to everyone’s satisfaction, they gave it a more up-to-date appearance and easier use.

We live in an increasingly noisy world. Fortunately, there is a solution to that at workplaces: 3M Peltor communication headsets are global leaders among two-way and active listening headsets to be used in dangerous and noisy environments. A wide range of headsets and hearing protectors can be used in several types of environment, and they comply with most requirements related to communication- and hearing protective headsets. A device like this can be the best friend of the ears.

A priority area of occupational safety is the protection of human skin. The skin’s protective layer always needs to include a certain amount of moisture and fat to be able to operate properly. If this condition is met, its flexibility and closed surface can prevent potentially harmful substances from passing through it. During work, special attention must be paid to chemical substances coming into contact with the skin. At 3M, you can also find solutions that reduce skin damage and skin tearing.

Although the intensive home office work due to COVID-19 causes it to take second place, every person working with a laptop should still protect data appearing on screen at their workplace and outside of work! It is hardly surprising that they have also thought of that at 3M: privacy screen protectors prevent visual data thieves from stealing data by looking at the screen from the side, while they ensure a sharp and clear view to users from the front.

Speaking of COVID: N95 masks, having crucial importance in the prevention of the epidemic’s spread, were also developed by 3M engineers and they are used since 1972. The demand for this product that is extremely useful for filtering particles of the virus became so great that the president of the US wanted to prohibit the export of N95.

We hope that we managed to show some snapshots from 3M’s colorful world. Browse 3M products distributed by us, so that you can find the best of the most useful products for yourself or your company! We are proud that we can represent the global company from Minnesota in Hungary.