Archive for category: About adhesives

All you need to know about metal adhesive systems

Where fasteners and welded bonds used to be of paramount importance, metal adhesive systems are becoming more and more popular. Metal glue and tapes bring along many benefits and cancel the disadvantages of mechanical bonds and seals. However, as there are different types of metals, also many types of metal bonding adhesive are available including machinery and structural adhesives.

Bonding metal with glues and tapes is highly possible, even recommended. However, the choice of the right metal adhesive may be a challenge due to the wide variety of different kinds of products which each have unique properties. Here you find the benefits of metal adhesives, the different types of metal glue and the suitable solutions for various types of metals, metal on metal glue options and how to glue metal to metal and to other materials.

Why you should choose for metal glue

Metal adhesives create chemical bonds which, in many cases, are preferred to mechanical fasteners, soldering and welds, especially when bonding metal to metal. Not only is metal glue often the more cost efficient option, but it also reduces the steps in assembly lines and so speeds up the process as a whole. The main reason for reducing the assembly steps is that adhesives not only bond but also seal. Thus the metal adhesive and sealant allow for application in one go. The bond (or seal) can also be flexible allowing for relative movement of the parts without affecting the bond. That is why metal adhesives are a go-to solution for products that are subject to vibration, temperature fluctuation and weather, such as trucks and other vehicles.

Metal adhesive vs. fasteners

Fasteners such as bolts and screws are very common methods of bonding for temporary joints. Fasteners are also suitable for semi temporary joints such as those in automotive assemblies. Nevertheless, problems may occur as fasteners require carefully placed holes, are prone to corrosion and may loosen over time.

This is where metal adhesives come into picture: removable glues and tapes are suitable for temporary bonding, and they do not leave traces behind after removal. Adhesives are also suitable for semi temporary joints as they seal from corrosion, are generally lighter and cheaper than mechanical fasteners, and distribute the stress throughout the bond making the assembly stronger. Some metal bonding adhesives come with special properties such as chemical resistance and heat resistance. Heat resistant glue for metal is common in public transport vehicles, automotive industry and general industrial applications. Metal glue can also be used for supporting fasteners: threadlocking and thread sealing are common applications where a metal glue makes sure the fastener does not loosen over time.

Gluing metal to metal vs. welding

Welding is a common method of bonding metal to metal in assembly operations. In a way, welds resemble adhesive bonds: both bonds are uniform and allow for equal stress distribution. They also do not require holes unlike fasteners. However, in applications that make use of welds, the labor costs are likely to be higher as the application requires special training and certificates. The welds also require inspection afterwards, bringing along more costs. With metal to metal adhesive this is not the case as most applications require only basic training and inspection is not necessary.

In bonding metal to metal, adhesives protect from corrosion whereas welds might even encourage it. Using adhesives also eliminates the rapid heating and cooling in a welding process. The drastic temperature fluctuations can cause the metal to weaken or discolor. Metal to metal glue applications usually do not involve as high heat as welding leaving the metal unharmed.

4 types of metal adhesive systems

Generally, metal adhesives can be divided into two groups: machinery adhesive and structural adhesive metal bonding. The latter refer to adhesives that are capable of bearing structural loads. These include epoxy glue for metal and acrylic metal adhesives. The other group is machinery adhesives which include those suitable for threadlocking and thread sealing as well as some special application which do not have to carry structural loads.

4 most common adhesives for gluing metal to metal and metal to other materials

1. Epoxy is one of the strongest adhesives for metal. It exists in different types which have unique properties such as chemical resistance and heat resistance. Epoxies come as one or two component systems. Single component epoxy glue for metal cures as a result of additional heat. A 2K system is a mixture of two parts with react with each other starting the curing process. When looking for the strongest glue for metal, a 2K epoxy for metal should be considered.
2. Acrylic metal glue exists as two types: surface activated and and bead on bead acrylics. The latter refers to applying a bead of adhesive on both substrates before connecting them. The bonding starts when the parts comne in contact with each other and become subject to pressure. Surface activated acrylics, in turn, require a water thin initiator applied to one substrate and the resin to the other.
3. Cyanoacrylate, also known as instant adhesive, is the super glue for metal to metal bonding. Cyanoacrylate adhesives is suitable for most metals as long as they are reactive. Therefore, the super glue for metal works better on brass and copper than on steel. Due to the excellent performance as metal glue, commercial cyanoacrylate adhesives are very popular among miniature and modeling hobbyists.
4. Anaerobic metal adhesives are only used for gluing metal to metal as they require presence of metal and absence of oxygen to be able to cure. Anaerobic adhesives are ideal for securing fasteners in terms of threadlocking and thread sealing as well as gasketing and retaining.

Other metal adhesives

Metal bonding can additionally, be realized by using MS (modified silane) polymers which are common when bonding metal sheets in vehicles like trains and buses. When invisible bonds are required, UV curable transparent systems should be considered. In case you are curious for more metal bonding solutions, contact us and let our experts guide you through the possibilities.

Bonding solutions for different types of metals

Not only are there many types of metal glue, but the range of different types of metals is also broad. Therefore, before choosing an adhesive system, you must know the metal that requires bonding: its properties have a great impact on the choice. Here you will find some common types of metal and suitable metal adhesive systems for different metal bonding applications.

Bonding aluminum with metal glue

When working with aluminum, it should be kept in mind that the metal is prone to corrosion and often has a thin oxide layer on it. The oxide layer forms a good surface for adhesives to adhere, however, the layer does not have a strong bond with the aluminum. Thus, to create strong bonds between aluminum and other materials, the adhesive should not be applied on the oxide layer, the layer should rather be removed. The best method to remove aluminum oxide is using solvent wipes, such as acetone or isopropanol, and abrading or grit blasting the surface.

After the surface preparation by abrasion or grit blasting, and appropriate cleaning, the surface is ready for the metal adhesive. Let’s look at the types of adhesives:

ANAEROBIC ADHESIVES – Even though aluminum is a passive metal, some anaerobic systems can be used for close-fitting concentric parts of threaded components. For softer aluminum alloys, anaerobic glues are suitable for gasketing and flange sealing.

EPOXY SYSTEMS – One component epoxy glues are ideal for aluminum bonding. They are easy to apply and cure fast when heated. Also 2K epoxy glues are suitable for aluminum. They generally form the strongest bonds.

CYANOACRYLATE GLUES – All grades of cyanoacrylate adhesive, instant glue, bond aluminum extremely well. Special formulations of super glue for metal form a considerable option when bonding aluminum to dissimilar surfaces with different coefficients of thermal expansion.

ACRYLICS – Structural acrylic adhesives are very suitable for aluminum. Both types, surface activated and bead to bead acrylics, are suitable for aluminum.

As many types of adhesives meet the needs of aluminum, the choice should be based on the adhesives suitability to your process, desired curing method and the required resistance.

Which metal adhesives bond brass?

Brass is an alloy which consists of zinc and copper. Brass is non-magnetic and resists corrosion: therefore, it is common in pipe joints, hydraulic fittings, heat exchangers, musical instruments and door locks and knobs.

For bonding brass, the options are open as the metal is rather easy to bond and many metal glues adhere well to it. The options include:

CYANOACRYLATE SYSTEMS – When bonding pads to musical instruments cyanoacrylate super glue is a preferred option. The strongest glue for metal often is methyl cyanoacrylates. However, when the bond needs resistance to impact or polar solvents, structural adhesive for metal bonding should be considered.

ANAEROBIC ADHESIVES – Brass is among the most reactive metals which causes anaerobic adhesives to cure much faster than when applied to, for instance, steel. On brass, anaerobic glues are used for threadlocking, thread sealing, form in place gaskets, retaining and weld sealing. These metal bonding adhesives exist as permanent and removable systems depending on the application. The applications also include pipe connections for oxygen and potable water pipelines.

STRUCTURAL ADHESIVES – Both epoxy and acrylic adhesives are highly suitable for bonding brass. Similarly to aluminum, all types are applicable: heat curing 1K epoxy, reactive 2K epoxy, and acrylic glue all do the job depending on the application.

Due to the wide variety of possible metal adhesives for brass, the choice should be based on the needs of the application, the adhesive´s compatibility with existing processes and the environment´s requirements.

Metal adhesives for copper

Copper and its alloys are readily bonded with a wide variety of different metal adhesives. For copper, adhesives are often the preferred option as they do not cause heat damage on the metal unlike soldering.

The most commonly used metal glues for copper include:

ANAEROBIC GLUES – As anaerobic adhesives require the presence of a metal and absence of oxygen to be able to cure fast, copper offers a perfect substrate due to the fact that it is one of the most reactive metals. That is why anaerobic systems cure much faster on copper than many other metals as steel. The uses include threadlocking, thread sealing, weld sealing, gasketing and munitions sealing.

EPOXY GLUE FOR METAL- Both one part, heat curing epoxies and 2K reactive epoxy glues are suitable for bonding copper. Epoxy glue for metal is ideal for forming strong metal to metal and metal to other material bonds.

CYANOACRYLATE ADHESIVES – Instant adhesive for metal offers the fastest curing time and results in increased efficiency. It is also highly compatible with copper. Nonetheless, when polar solvent resistance and impact resistance are the requirements, an epoxy or acrylic adhesive offers the right solution.

ACRYLIC SOLUTIONS – When it comes to acrylics, both surface activated and bead to bead systems support copper bonding. Both result in strong structural bonds.

Stainless steel adhesive systems

Stainless steel is generally an easy metal to bond, however the mirror-finish stainless steel may be a tricky metal to apply adhesives to as it usually has a very low texture surface which prevents adhesion. A Stainless steel surface without mirror-finish requires little to no surface preparation and can be bonded with the following systems:

ANAEROBIC SYSTEMS – threadlockers, thread sealants, gaskets and retaining compounds all work well as glue for stainless steel. However, the curing time of anaerobic adhesives is rather long due to the fact that stainless steel is a passive metal.

CYANOACRYLATE ADHESIVES – All grades bond stainless steel rather well. The strongest bonds form when using special products designed for metals like steel.

STRUCTURAL GLUES – Structural adhesives such as epoxy and acrylics provide heat and chemical resistance. Generally, epoxy is the tougher option, yet it always depends on the application and the environment.

If you are working with mirror-finish stainless steel, before applying any steel adhesives, you should create more texture on the surface. The surface must be roughened, but methods like sandpaper, steel wool or scotch brite are likely to fail due to the hard surface of the material. On the other hand, automated roughening methods may generate heat, which can alter the metal´s surface properties and prevent adhesion. The best way to abrade mirror-finish stainless steel is sandblasting: it is efficient enough and involves no heat.

The strongest metal bonding glue for mild steel

Mild steel, sometimes called carbon steel, is a common material used throughout industries such as automotive and machine building. The key to successful steel bonding lies in proper surface preparation. The surface preparation includes appropriate cleaning and abrasion where needed.

Note that mild steel is often powder coated or otherwise painted prior to adhesive application. Then the metal adhesive forms a bond with the coating layer, not the steel itself.

ANAEROBIC SYSTEMS – Threadlockers, thread sealants, gaskets and retaining compounds all work well on mild steel. These result from the use of anaerobic steel adhesive systems.

CYANOACRYLATE GLUES – When strong, fast bonds are a must cyanoacrylate systems are a considerable option. For applications that require polar solvent and impact resistance, structural steel glue systems may offer a more suitable solution. For example retention dressings for bolts and nuts can be realized using cyanoacrylate metal glue.

STRUCTURAL SOLUTIONS – Structural adhesive for metal bonding such as epoxy and acrylics are famous for their heat and chemical resistance. Generally, epoxy is the tougher solution, yet it always depends on the application and the environment.

Several steel adhesive systems are suitable for bonding mild steel: to determine the right one, it is important to consider the correct chemical, weather and temperature resistance.

Metal adhesives for magnets

Strong, even permanent magnets are present in many assemblies, the most important ones being electric motors and speakers. Magnet types differ from each other by strength, cost as well as temperature and corrosion resistance. Some types of magnets include neodymium, rare-earth, AlNiCo, samarium cobalt and ferrites. Usually, magnets allow for bonding without surface preparation. However, to achieve the strongest bonds, isopropanol can be used for cleaning the surface.

There are many metal adhesives that bond magnets more than well. Here are some of the most common metal adhesives for magnets:

CYANOACRYLATE ADHESIVES – These instant adhesives create strong bonds at high speed as their curing time is very short. When the bond must be resistant to polar solvents, high temperatures or impact, structural adhesives should be considered.

EPOXY SOLUTIONS – One and two component epoxies are both suitable for bonding most magnets. One should always confirm the compatibility of the adhesive and the specific magnet by checking with the metal adhesive manufacturer.

ACRYLIC GLUES – Due to the fact that structural surface activated acrylic metal glue systems have a fast set time, they are often a preferred solution for high speed motor assemblies. External 2K mix systems are the alternative.

Looking for the perfect metal bonding adhesive for your application?

The range of metal adhesives and types of metals is broad making the choice of an adhesive extremely tricky. Our experts are always willing to share their expertise and guide you towards the ideal solution. Hit the button below and find the perfect metal glue for your application.

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EXTRA: the best metal glue for DIYers

Metal adhesives not only are industrial systems, but they also often come in handy for small fixes in and around the house. The types of metal glue that are the most suitable for do-it-yourself applications include epoxy, polyurethane and cyanoacrylate (super glue).

EPOXY – epoxy metal glue can be rigid or flexible, transparent or opaque and fast or slow setting. They are predominantly two part systems and are suitable for applications such as door handles, handrails, table legs and jewellery. Like industrial epoxy adhesive, also the one for home use is heat and chemical resistant as well as suitable for rebuilding, filling and repairing applications.

POLYURETHANE – Polyurethane adheres well to most metals and is water and UV resistant making it ideal for outdoor applications. There are many jobs in and around the house that can benefit from polyurethane metal adhesive. Especially moisture curing polyurethane is often referred to as the best exterior metal adhesive.

CYANOACRYLATE – super glue is perfect for almost any household fix: it is easy to apply and cures in the matter of seconds. Common applications of super glue for metal include car parts, ornaments, appliances and numerous other everyday items. Also miniatures and models as well as prototype electronics can benefit from super glue thanks to its excellent performance in gluing metal.

Solvent free adhesives grow in popularity

The growing interest and consciousness towards environmental responsibility is resulting in new technologies also in the adhesives industry. Solvent free adhesives are becoming more and more popular as they contribute to a greener future, user safety and reduced environmental impact.

But what is solvent free adhesive? For adhesives to be called solvent free, they must not contain more than 5% solvents. Therefore, several different technologies have been developed to reduce or eliminate the solvent content of the systems. The technologies include solvent free glue, hot melt and high solids adhesives as well as waterborne systems. All these systems are considered low VOC adhesives.

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Ever increasing uses of solvent free adhesive solutions

First solvent free adhesives were a solution for low demand applications. However, as the technology is continuously improving, non solvent adhesives are becoming a desired solution in many industries. The industries that already rely on these low VOC adhesive solutions include the following.

• Automotive: interior fittings such as headlinings and dashboards
• Packaging: especially lamination systems for flexible packaging
• Furniture: bonding and sealing upholstery
• Mattress: bonding mattress layers together
• Paper: envelopes, bookbinding etc.
• Textile and shoes: apparel and footwear, bonding upper to the sole
• Hygiene: for example napkins, sanitary diapers and other non woven materials
• Medical: solvent free adhesive pand-aids, surgical glues and cements for bones
• Construction: non solvent based construction adhesive systems as multi purpose solutions

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Non solvent adhesive systems beat solvent solutions

The main reason for choosing for solvent free adhesives is the reduced environmental impact they have. The nearly or completely solvent free adhesive systems are safer for the environment and for people due to the fact that they do not emit nor contain much VOC (volatile organic compound). These non solvent, low VOC adhesive systems have, nevertheless, more advantages than just that.

• Lighter weight: bonding products that do not contain solvents tend to be lighter in weight both during the production and in finished products.
• Fewer product requirements: many countries set high requirements for chemical products that are allowed to be imported, especially regarding VOC. As solvent free adhesives have close to zero VOC, export is also easier.
• Fewer occupational safety requirements: in regards of occupational safety, non solvent adhesives have less requirements since processing them does not involve the possibility to inhale VOC emissions.
• Reduced health risk: The absence of VOC means safer end products since no hazardous chemicals have been used in the no solvents adhesive systems.

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Low VOC adhesive systems by different technologies

As solvent free adhesive systems are increasing in demand, there are several ways to realize them. The technologies resulting in non solvent adhesive solutions include hot melts, high solids, solventless and waterborne solutions which we will take a closer look at below.

Hot melt and high solid non solvent adhesive solutions

One of the newer non solven glue technologies is hot melt adhesive. Generally, hot melts are 100% solids formulations leaving no space for solvents – the perfect solution when one is looking for a water and solvent free adhesive. They are thermoplastics which appear in a solid phase in room temperature. However, when the temperature is elevated, they become liquid with a good flow. After application, it only takes seconds before the non solvent glue solutions are back to solid phase forming strong bonds and seals – all without the use of solvents.

The hot melt adhesives are traditionally applied by spraying due to their reaction to temperature. However, they can be made rollable by reducing the solid share (usually to about 75%) making them liquid also at room temperature. This, however, means that some solvent will be involved but as long as it does not exceed 5%, they still can be classified as non solvent adhesives. Hot melts also exist as biodegradable systems currently used in the packaging industry.

Do not hesitate to contact us in case you require any additional information on the hot melt adhesive technologies.

Solventless adhesives

Solventless adhesives traditionally do not contain any solvent and were first developed for the packaging industry, more specifically as lamination for flexible packaging. Solventless adhesives were first used for low demand applications only. Due to continuous development, they are now good for any lamination application, even when high temperatures or chemicals are involved.

These solvent free adhesives carry the benefit of lower machinery costs. Even though machinery made for solvent based products cannot be used for this non solvent glue, the initial investment of new machinery is remarkably lower.

Water based dispersions as solvent free glue

The most traditional no solvents adhesive solution is water based. These adhesives use water instead of solvent as the carrier agent. They cure through water evaporation. Despite the fact that these adhesives are very traditional, they still know several innovative applications, for example, solvent-free adhesive tapes.

Please find more information on waterborne adhesive and sealant solutions in our article dedicated to the topic.

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Take a step towards greener future with solvent free adhesive solutions

An increasing number of organizations take their environmental responsibilities more seriously and aim at altering their production means to contribute to a greener future. If you are also looking for solvent free adhesives for your product, do not hesitate to contact us. Our specialists are happy to assist you in finding you the best possible solution.

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Elasticity with silyl modified polymer adhesive and sealant systems

Silyl modified polymer adhesive and sealant solutions were first introduced in Japan in the late 80s. Today, there is a high demand for elastic bonding and sealing in industrial applications. These silane modified polymer-based systems have successfully entered the European and American markets. They are widely used in industries such as automotive, transportation, construction and many more.

Adhesives and sealants that rely on silane modified polymer combine the advantages of polyurethanes and silicones, and cancel all their disadvantages. Silane modified polymers can be applied to almost any surface, making modified silanes a perfect choice.

What is silane modified polymer?

Silane modified polymer (SMP), also known as silyl terminated polymer or silyl modified polymer, consists of a polymer backbone which is terminated by silane groups. The silane groups can be independent or supported by urethane groups. This gives us two main types of SMP adhesive and sealant systems: silyl modified polyethers (MS polymers) and silyl modified polyurethanes (SPUR polymers). The former are often preferred as sealants as they are more elastic and slightly less resistant than SPUR polymers. Both types of silane modified polymers are, however, also suitable for silyl modified polymer adhesive solutions.

Curing process of silane modified polymer adhesives and sealants

Modified silane polymer systems cure through polycondensation, also known as moisture curing, in room temperature. This means that the products use moisture in either the material or in the ambient to harden. With some products the curing starts from the outside and reaches the inside as last. Therefore, one must be careful not to apply too thick layers, as this may lead to poor curing and system failure.

Advantages of silyl modified polymer adhesive and sealant systems

Modified silane adhesives and sealants are the preferred option for many applications in a wide variety of industries. They are used for example for:

• fixing solar panels
• bonding side panels of trailers and vehicles such as trucks
• assembly parts
• container constructions
• doors and windows (also in vehicles)
• in sealing joints wherever elasticity is needed, for example in parking lots.

It is no wonder SMP adhesive and sealant systems are widely used, since they come with a great spectrum of advantages.

Advantages of silane modified polymers:

• Elastic bonds and seams: SMP adhesive and sealant systems remain flexible also after complete cure. The elasticity of the seams and bonds is not affected even by harsh environments.
• Easy to modify: silane modified polymer adhesives and sealants can have different polymer backbones which partially define their set of properties. However, the properties can also be modified with help of additives and so-called boosters.
• Minimum surface preparation: in most cases through cleaning and degreasing of the surface is sufficient. Usually, these systems do not require a primer, thus the process is sped up. Note that some silyl modified sealant systems do not cure in the presence of polyols: therefore, the cleaning substance should not contain these.
• Silicone and isocyanate free: most silane modified polymer solutions are environmentally friendly as they do not contain silicone or isocyanates. Some products may emit methanol during the hardening process, but also ethanol emitting, safer systems exist.
• Good adhesion to most materials: silyl modified polymer adhesive and sealant products adhere to most substrates such as concrete, plastic and metal allowing for a wider variety of possible applications.

Adhesives and sealants based on silane modified polymer

Due to the fact that the modified silane systems are easy to further modify, they exist as adhesives and sealants. The MSP adhesives have excellent adhesion to many substrates whereas the sealants provide watertight and chemical resistant seals.

Silyl modified polymer adhesive systems

Silyl modified polymer adhesive systems are various and versatile. As the formulations are many, so are the application possibilities. For example POR adhesives, based on silane modified polyolefin, are rather common in the automotive industry, where they are used instead of polyurethane adhesives.

Silyl modified polymer sealant systems

The silyl modified polymer sealant systems are known for their extreme elasticity and abrasion resistance. Although these sealants are not extraordinarily chemical resistant, they are strong and economical sealing solutions for example for airports. Especially the sealants´ ability to adhere to different substrates makes them a go-to solution in many cases. 

Silane modified polymer vs. silicone

When it comes to silane modified polymer sealants, they are most often compared with silicone sealants. The main difference between the two is that silyl modified polymer sealant does not contain silicone which is sometimes considered harmful. The MSP sealants are also paintable unlike silicone.

Looking for the perfect SMP adhesive or sealant for your project?

In case you are curious about what modified silane polymers can do to your project or product, or you would like to enquire about a silyl modified adhesive or sealant, do not hesitate to contact us. Our experts make sure your application gets the SMP system it deserves. Note that the silane modified polymers market is under continuous development and the systems are generally easy to modify. Therefore, manufacturers within the silane modified polymers industry usually are willing to collaborate with their customers to enable more uses of SMP systems.

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The need for Sustainable Adhesives for greener future

While the world’s growing population and increasing living standards boost the need for adhesives, environmental concerns encourage the development of greener, sustainable adhesives. Therefore, the need for sustainable adhesives has reached a completely new level. Innovative sustainable glue solutions are being developed based on ever-improving technologies. Additionally, more and more industries opt for sustainable adhesive products, which is no wonder as sustainability of adhesives is a hot topic for many reasons.

• Improved health and safety throughout the product’s lifecycle: sustainable adhesives contain little to no solvents. This means that less or no VOC (volatile organic compounds) are released during the application and curing. Neither do the finished product release VOC.
• Decreased environmental impact and carbon footprint: the absence of solvents results in less impact on the environment. This is due to lighter weight, less product needed and VOC emissions reduced to the minimum.
• Rules and regulations towards more sustainable products: sustainability has become a priority in development of new products and systems. Therefore, also governments strive towards the trend by setting rules and regulations for products. For example, the VOC emissions of chemical products have long been strictly controlled in the USA and EU. They also gain more and more importance in other markets such as Asia and South America.

Are adhesives sustainable?

Yes and no: many adhesives use fuel based raw materials which are harmful for the environment. However, it is possible to replace those raw materials completely or partially with materials derived from natural resources. The use of natural raw materials defines the sustainability of adhesives.

Innovation leads the development of sustainable adhesives

Sustainability of adhesives has many advantages, but achieving them requires modification of existing products and inventing new innovative technologies. Sustainable adhesives generally belong to one of three groups:

• Solventless adhesives: nowadays many adhesives are made with less solvents by increasing the solid share. However, among other methods, 100% solid adhesives such as hot melt contain no solvents at all. Hot melts are common throughout industries including the automotive sector.
• Waterborne adhesives: waterborne adhesives are developed using water as the carrier substance instead of a solvent. This provides the product with reduced weight as well as eliminating the VOC emissions as well as minimizing the risk for fire during processing. Waterborne adhesives are common for example in the mattress industry, where they replace solvent based systems.
• Biobased adhesives: to call a glue biobased, most of the materials in it must be natural such as starch, vegetable oil, resins, lignins and proteins. These materials guarantee reduced carbon footprint of the products.

5 types of trending green adhesives

The demand for so called green adhesives is ever-growing and encourages new ways of sustainability in adhesives development. Below you can find five types of sustainable adhesives that are likely to experience a boost in demand in the coming years. For any enquiries for sustainable adhesives, we encourage you to contact us, share your project´s needs and let us help you find the manufacturer to produce the system.

1. Renewable adhesives

Renewable adhesives refer to those made of materials such as beeswax and plants, and have no petroleum derivatives in their formulations. Not only do these sustainable adhesives reduce carbon footprint but also contribute to overall sustainability of a great number of applications including paper lamination, carton sealing and bottle labeling.

2. Recyclable adhesives

When an adhesive is recyclable, once the finished product has come to the end of its service life, the adhesive can be melted and recollected without producing any adhesive waste or residue. Recyclable adhesives are generally common in the automotive industry as well as in bonding glass, aluminum and steel.

3. Biodegradable sustainable glue

Biodegradable technology brings the sustainability of adhesives to the next level. The biodegradable adhesives are designed to be broken down by bacteria and other microorganisms. The degrading process produces water, carbon dioxide and other natural gases defined by the environment. These adhesives are mainly present in paper and packaging, envelopes, hygiene products and medical devices.

4. Compostable green adhesives

Compostable adhesives belong to the group of biodegradable sustainable glue. The main difference is that the compostable systems break down under specific (compost) conditions. These sustainable adhesives break down in industrial or domestic compost environments and the broken-down product is suitable for enriching soil. Compostability is currently present in packaging adhesives such as hot melts and PSA adhesives.

5. Repulpable adhesives

In paper and packaging, repulpable adhesives are likely to grow in popularity as they dissolve completely during paper repulping process. Used for instance in carbon boxes, envelopes and other paper products, repulpable adhesives are by far the most sustainable glue options. They completely dissolve without leaving any residue behind.

Choose for the right green adhesive systems

Sustainability of adhesives is of great importance regardless of the project or product. In case you need any assistance regarding sustainable adhesives, do not hesitate to contact us. Our experts are here to help, and happy to provide you with the best possible sustainable glue system for your needs.

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Biobased adhesives and sealants respond to the needs of the market

Due to growing world population and increasing living standards, the need for adhesives is greater than ever. At the same time environmental concerns and decreasing fossil resources discourage the use of fossil based materials. This has led to the development of biobased adhesives and sealants which work towards reduced carbon footprint while efficiently bonding different substrates.

Instead of relying on traditional fossil-based raw materials, bio adhesives and sealants consist of renewable, biobased materials such as starch, vegetable oils, proteins, lignin and natural resins. Not only are biobased adhesives and sealants environmentally friendly, but they also have beneficial mechanical and chemical properties that contribute to their efficiency.

Materials that make up bio based adhesives and sealants

The raw materials used in biobased adhesives and sealants are derived from biomass which is mostly produced by the agricultural and silvicultural processes. Consequently, these materials are climate-neutral and the finished bio based adhesives and sealants do not affect the environment. See the biobased materials that can replace petroleum based polymers, tackifiers and waxes in the table below.

Biobased material type	Ingredients in biobased adhesives and sealants
Polymers	Soy protein Starch esters Polyamide Polylactide
Tackifiers	Pine rosin Terpene Citrus
Waxes	Soy Castor Dimerized fatty acids

Different types of biobased adhesives and sealants

The term bio-based adhesives and sealants generally refers to systems that consist of biobased materials up to a certain point. The first biobased adhesive and sealant systems were general purpose, waterborne solutions that benefitted industries like packaging, furniture and textile. However, as the technology has advanced, there are now specific adhesive and sealant systems for specific industries. Currently, the packaging industry benefits the most from bio based adhesives and sealants.

The bio based adhesive and sealant systems are no longer limited to waterborne dispersions and emulsions, but they also exist as hot melt systems and pressure sensitive adhesive solutions.

From biobased to biodegradability and compostability

When biobased adhesives and sealants contain enough natural raw materials, they can be classified as biodegradable or compostable. These two terms are often used as synonyms, nonetheless, they are not exactly the same: the main difference is that biodegradable products break down naturally whereas compostable systems require a certain setting in order to break down.

Compostable or biodegradable bio based adhesive and sealant systems exist for example as heat seals and general packaging adhesives.

European Norms EN 16785 and EN 13432 assess bio-based adhesives and sealants

When biobased adhesives and sealants first were introduced, there were neither internationally acknowledged standards nor testing for biobased materials. In order to make it easier to define biobased materials and products that use them, several standards exist nowadays. The most important ones are the European Standards EN 16785-1 and EN 13432.

• EN 16785-1 verifies biobased content of products in two ways: by radiocarbon analysis and elemental analysis according to CEN/TS 16440 for Carbon- 14 component. The standard EN 16785-1 defines biobased as “derived from biomass”. The biobased adhesives and sealants are thus those partially or entirely made of materials derived from biomass. The standard covers a broad range of products since it is applicable to solid, liquid and gaseous compositions which contain carbon.
• EN 13432 evaluates biodegradability of adhesives and sealants by four tests: biodegradation, disintegration, ecotoxicity and heavy metals. An adhesive or sealants is biodegradable if 90% of the total mass of the adhesive is turns to CO2 within 180 days, the germination rate and plant biomass in the compost are more than 90% of those in the corresponding blank compost, the products resulting from composting process are suitable for enriching soil or do not harm floral growth in the area, and the heavy metals in the product do not exceed the limits set in the standard.

Certified bio based adhesives and sealants benefit manufacturers and buyers

Obtaining a biobased certificate helps manufacturers demonstrate the biobased content of their products on the labels. This increases the trustworthiness of the products and company in general.

As for the buyer, it is good to look for products that have biobased certification according to EN 16785 or another similar standard to be sure of the contents of the product.

Interested in bio-based adhesives and sealants?

Biobased adhesives and sealants are gaining more and more share on various markets ranging from wood and construction to paper and packaging. In case you would like to receive more information on biobased products, or like to enquire about a suitable biobased solutions for your process, do not hesitate to contact us.

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Carbon neutral buildings with low carbon adhesives for construction

In recent years, carbon neutral and low carbon buildings have caught more and more attention. The common trend is shifting towards environmentally friendly solutions, lower carbon dioxide emissions and generally greener buildings. Carbon dioxide emissions are part of every phase of a building’s lifespan: manufacturing raw materials, construction, use and demolition. Next to the use phase manufacturing accounts for the largest environmental impact. This is where low carbon adhesives for construction come into the picture. To reduce a building’s carbon footprint, low carbon adhesives are applicable on construction timber, windows, door areas and many other applications.

The carbon footprint of construction adhesives

The construction adhesives exist in four groups: water-based dispersions, hot melt thermoplastics, solvent based glues and reaction adhesives. The amount of adhesives used in constructions is rather small compared to most other building materials. However, the carbon footprint of the adhesives contributes to the overall footprint of the building.

Of these four, reaction adhesives have the most negative environmental impact, whereas water-based dispersions have the smallest carbon footprint. Thermoplastic hot melts are often considered a green option, and solvent based glues are thought to have negative impact on the environment. However, surprisingly they share the same size of carbon footprint. Naturally, the actual environmental impact of adhesives is dependent on the product´s formulation and composition. This means that not every solvent based glue has low impact, and that reactive adhesives can also have lower impact.

Eco-friendly buildings with other low carbon materials

Sometimes achieving the smallest carbon footprint requires the use of less environmentally friendly adhesives combined with bio-based building materials. These materials include wood and innovative materials derived from it. In these cases the carbon content of the adhesive is not important as long as the bonds hold without replacing or maintenance for as long as possible.

Different applications of low carbon construction adhesives

Low carbon adhesives for construction are usually water based dispersions, or at least solvent free. They know numerous compositions and formulations, each having a design for a specific application.

Some of the uses of low carbon adhesives for construction include bonding and sealing windows, making stairs as well as laying wall and floor tiles. However, glues also play a role of paramount importance in providing strong and carbon neutral structures, especially in wooden buildings. Timber constructions have been proven to be as strong as concrete and steel but lighter in weight, lower in cost and carbon neutral. Adhesives are suitable for laminating timber enabling beams that are sufficiently strong to be for use in bearing structures.

More information on low carbon glues

As carbon neutral buildings become more and more desired, low carbon adhesives for construction are growing in popularity. In case you wish to gain more information on low carbon possibilities, or are looking for a supplier for your project, click the button below and share your project with us. Our experts are happy to help you find the right adhesive system for your project or product.

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Repair instead of throwing away – super glue and other adhesives for DIYers

Glues are used almost everywhere from heavy industrial processes to everyday consumer goods and small home repairs. Adhesive like super glue is also a great thing to have at home, in the car or somewhere else within hand’s reach. There are several types of adhesives that are perfect for home repairs and DIY projects. They can save you money as you can repair broken items without needing to buy new ones.

Super glue is by far the most well-known adhesive used in repairs, yet it is not the only option. There are numerous adhesives that can be used for a wide variety of applications. Here we will take a look at the most common glues used in households including super glue, epoxy, wood adhesive and silicone based glues.

Super glue – the best adhesive for small repairs

Substrates: Metal, rubber, wood, ceramic, plastic and porcelain

Super glue is an adhesive that ended up on the list of most useful inventions in the 20th century. And that is no wonder, as the cyanoacrylate based glue bonds almost anything as long as the surfaces are small and flat. Super glues not only are superior repair adhesives to use at home, but industrial super glue also performs well even in heavy duty applications.

Super glue properties and curing

Generally, there are two types of super glue: gel and glue. Both of these have superior bonding power. The difference is that gel is less likely to drip and leak. Super glue is often called instant glue as it cures in a matter of seconds. You should, however, not be fooled by the very short curing as the full cure may take up to 24 hours. Therefore, after gluing the parts together, you should let the adhesive cure longer and keep the parts together with clamps or zip ties to preserve the true super glue properties.

Where to use instant glue

Most super glues are suitable for a wide range of substrates and they are ideal for glueing broken dishes, shoes, tears in car upholstery, disconnected car mirrors, handles, hoses and many more applications. You can even super glue metal to wood, an application where other general repair adhesives often fail. Just make sure the manufacturer confirms the use of their instant glue product on the specific material.

The best super glue products

As instant glue is a preferred product for many applications, multiple brands offer these products. Although everyone has their own preferences, two brands can be said to be more popular than the rest: Gorilla and Loctite.

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Where NOT to use super glue

Even though super glue is very strong, it is not the best choice for filling gaps and cracks. This is due to the fact that super glue forms thin, transparent layers which are not hard enough to remain in form. For gap and crack filling, you could use super epoxy glue instead.

Strong bonds on large surfaces with epoxy glue

Substrates: Metal, plastic, wood, fiberglass and composite materials

Epoxy is one of the strongest adhesives for industrial and consumer use. It is usually a two component system which is sold a set of resin and hardener packed separately. Prior to application, the two components must be mixed with each other on a surface like newspaper or cardboard. When the components are mixed, the chemical reaction that results in curing strats. Therefore, the epoxy glue must be applied soon after mixing. Note that also single comonent, easy to apply epoxies exist: these are sometimes called super epoxy glue, as the properties resemble those of super glue.

Epoxy curing time

Epoxy cures when two components are mixed with each other and a crosslinking process is started. Some epoxy products cure faster than others however, the rule of thumb is the longer the curing time the stronger the bond. Like super glue, epoxy should be let cure for 24 hours to reach its full strength. Use clamps or zip ties to create pressure and keep the parts in place until the adhesive is fully cured.

Where to use epoxy glues

Epoxy glues work the best where super glues don´t: large surfaces and crack and gap filling are common applications. Epoxy cures into a plastic like, transparent or opaque bond which is hard to beat it toughness. Therefore, epoxy beats super glue in strength also when bonding metal or wood. Common epoxy applications include shoe repairs, fixing handles (for example screwdrivers) and minor car repairs including disconnected mirrors and patch cracked lights.

Best epoxy products for home repairs

Some of the most popular epoxy glues for home repairs include Gorilla two part epoxy and Bob Smith quick-cure epoxy..

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Wood adhesive for crafts and repairs

Substrates: wood

Wood is a porous material and requires a special adhesive which soaks into the pores. The wood glues are used for wood to wood bonding and it is common for crafts and home repairs. Wood glue is usually white and becomes transparent as it hardens. The glue should be applied by spreading an even amount on both surfaces that are about to be banded. After that the parts are connected and should be clamped together to ensure they stay in place till the glues is fully cured.

Curing wood glue

Like for super glue and epoxy, the longer the product is let cure, the stronger the bond. Many products are available and they all have specific curing times. Stick with the manufacturer’s advice to achieve the best result.

Get the best wood glue products

Titebond III ultimate wood glue and Gorilla wood glue are among the most popular wood glue products as they are easy to apply and form strong transparent bonds in wood to wood applications.

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Silicone glue for watertight bonds

Substrates: Glass, plastic, metal and wood

Better known as sealant, silicone creates watertight bonds which resist chemicals and weather. Therefore, the best use of silicone glue is sealing there where adhesive properties are needed, too. Silicone glues cure to form a transparent or colored bond which remains flexible under any circumstances.

Uses of silicone glue

As mentioned, silicone glue is often used in applications that require both: sealing and bonding. Common uses of silicone glue in home repair projects include bathrooms and glass to glass connections such as in building and repairing aquariums. Silicone is also suitable for outdoor applications thanks to its superior water and weather resistance. Other uses are door frames, vinyl tops, roofs, shoes, toys and many more.

Best brands to work with

Permatex clear RTV silicone adhesive sealant and loctite clear silicone waterproof sealant are two products that work extremely well when silicone is the desired material.

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Epoxy adhesive – the most used industrial adhesive

Epoxy adhesives are by far the most common industrial adhesives and probably the most versatile structural adhesives. The popularity of epoxy adhesive is not the least due to the extreme toughness of the cured product nor their incredible ability to adhere to a wide range of materials. Epoxy resin adhesive systems are also easy to modify to make them meet the unique property needs of every individual project.

Epoxy adhesives are realized using different epoxy adhesive resin types which define the fundamental properties of the adhesive. The most suitable and strongest epoxy for specific application is usually determined by looking at the resin: a heat proof epoxy resin is the best when high temperature resistance is required where as a flexible epoxy resin is the go to solution when movement may be involved. Here yoy can find the general benefits of epoxy resin adhesives as well as the most common epoxy resin types and some epoxy adhesive applications.

What is so special about epoxy adhesives?

The presence of epoxy groups in the chemical formulations of the adhesives grants them several advantages. Epoxy resin adhesive can be modified and given desired properties rather easily, but all epoxy adhesives share some characteristics including:

• Chemical resistance: generally, all epoxy resins resist chemical exposure better than most alternatives. With modification epoxy adhesives can even withstand total immersion in harsh chemicals.
• Heat resistance: due to the chemical composition of epoxy, the adhesives are heat resistant by nature. Also a property that can be enhanced by modifying the formulation. Usually, epoxy adhesives are heat resistant up to 200°C (390°F). However, also heat proof epoxy resin types exist which withstand even higher temperatures.
• Durability and final strength: once cured, the epoxy bonds are among the strongest in industrial applications: they even hold the truck lift world record using adhesive, having lifted a 17, 500 kilogram truck. They also retain stability over a long period of time. Industrial epoxy adhesive systems that use various resins are among the strongest epoxy systems.
• Electrical properties: one of the desired properties of epoxy resin adhesive is its excellent electrical insulation which makes it suitable for applications like printed circuit boards.
• Watertightness: probably the most well known property of epoxy adhesives. Not only do they create strong bonds, but also effectively seal and make joints and gaps watertight.

1 compoonent and 2K epoxy resin adhesive

Epoxy adhesives exist in one and two component glue systems, which both form extremely strong bonds, but differ from each other by curing process and final properties as well as applications. 2K epoxy resin adhesive is generally tougher than single component systems.

2K epoxy glue

The two component epoxy resin adhesives are greater in versatility, as they are used in all market segments. They are slightly more complex to process, as the two components, resin and catalyst, must be mixed with each other, and the worklife is limited from a few minutes to a couple of hours depending on the industrial epoxy adhesive formulations. These 2K epoxy resin adhesives cure in ambient temperature, but the process can be sped up by applying heat or an external source of energy such as UV light depending on the formulation. Generally, the epoxy adhesives cure to the toughest bonds when the curing period has been the longest.

The major advantage of 2K epoxy glue solutions is that they adhere to almost any surface including wood, metals, plastics, ceramics and various types of rubber. They also are resistant to physical and chemical influences including heat resistance to 95° to 200°C (200°F to 390°F).

Single component epoxy glues

One component epoxy resin adhesives are easy to process as they do not require mixing unlike 2K epoxy glue. They usually have a paste-like consistency which makes them ideal for application by trowel or extrusion by beads. These adhesives cure in elevated temperature between 120° and 175°C (250° and 350°F) depending on the formulation. The single component heat cure adhesive systems fill and seal gaps efficiently, particularly between metal surfaces.

One part epoxy adhesives also appear in a form of heat curing film adhesive. The film adhesives are the best applied on large areas for bonding or laminating purposes. These films are found for example in the aerospace industry in assembly compounds. The one part epoxy resins adhesives are also common as construction epoxy adhesive which can be applied for instance when laying tiles.

5 common types of epoxy resin adhesive

Epoxy glue is not simply just one and two component adhesives, but many formulations exist depending on the resin, catalyst, modifiers and additives. The most important ingredient that gives the system most of its properties is the epoxy adhesive resin. It is also possible to use a combination of resins in order to guarantee the best possible solution. Here we will take a closer look at the five most common epoxy resins used in adhesives. In case you require any additional information on these or other types of epoxies, contact us and let us find the solution that benefits your application the most.

1. DGEBA epoxy resin

Diglycidyl ether of bisphenol A (BPA), better known as DGEBA epoxy, is the oldest epoxy resin, and by far the most important in epoxy adhesive formulations, not the least due to its relatively low cost of raw materials. Additionally, this resin is compatible with a wide range of catalysts allowing for a broad selection of properties to be created. The industrial epoxy adhesive systems using DGEBA epoxy, cure either in room temperature or with additional heat.

DGEBA epoxy resin exists as low molecular weight liquids, high molecular weight semi solids and solids as well as brominated resins. The latter are used primarily for application requiring ignition resistance. Therefore, brominated resins are common for example in circuit boards and other applications where flame retardance is needed.

2. Epoxy novolac adhesives

Epoxy novolac adhesives are best known as the most chemical resistant and high temperature resistant epoxies. They also have better adhesion than the BPA epoxies. In order to develop these properties to their best, the epoxy novolac must be cured in a high temperature. When cured in room temperature, the properties that can be achieved are similar to the ones of DGEBA epoxy adhesives. The length cycle of the curing process significantly affects the thermal stability of the cured bond.

Epoxy novolac resins are generally complex to process due to their high viscosity. Low viscosity alternatives have recently been developed in order to ease the processing. However, these products tend to have lower epoxy resin content. Whatever the case, epopxy novolac is almost predominantly a 2K epoxy glue.

3. Flexible epoxy resin glues

Epoxy glues and adhesives are generally not known for their flexibility. However, long chain aliphatic epoxy resins make it possible to add flexibility to the properties of epoxy adhesives. Nevertheless, the addition of this flexible epoxy resin compromises on toughness of the glue. Therefore, flexible epoxy resins are generally not used alone but rather mixed as modifiers with other epoxies to create a tougher and stronger yet flexible solution. When the resin content comprises of aliphatic epoxy for 10-30%, a required level of flexibility can be achieved without remarkably influencing other properties. These are the best flexible epoxy adhesive systems.

Flexible epoxy resin adhesives are used for instance for laminating safety glass, dampening vibration and sound as well as encapsulating electrical components and other delicate components that require thermal cycling.

4. Waterborne epoxy adhesives

By nature, epoxies are hydrophobic, thus not dispersible in water. Water dispersibility can, nonetheless, be conveyed to epoxies in two ways: chemical modification or emulsification. The latter is primarily used for resins in waterborne epoxy adhesives and done by separating the water from the resin with a surfactant. The choice of the surfactant and processing parameters determine the mechanical and chemical stability of the adhesive.

5. Epoxy acrylate resins

When formulating adhesives, two types of epoxy acrylate resins are used: vinyl ester and a special resin for radiation curing. These resins act more like polyester resins despite of being epoxies. They are easy to process, cure fast at room temperature and can use peroxides as the curing agent. In adhesives, these epoxy resins create lower viscosity, more flexibility and better wetting characteristics than conventional DEGBA epoxies. However, they do shrink more than any other epoxy adhesive while curing.

The epoxy acrylate resins can also be cured by radiation from an external source of energy such ultraviolet (UV) or electron beam (EB). These epoxy resin adhesives are generally low in viscosity and high in vapor pressure.

Examples of epoxy adhesive applications

As epoxy glue is a versatile product that exists as many formulations, the uses of the different types are nearly endless. Here below you can find some examples of tepoxy adhesive applications.

• Chemical and biochemical industry: due to its outstanding chemical resistance, epoxy adhesives are common in applications that involve harsh chemicals. Especially epoxy novolac based formulations are used in tanks and other means to store chemicals.
• Automotive industry: the strength of epoxy is also needed in the automotive industry where adhesives are replacing conventional fasteners and welded bonds, as they are remarkably lighter in weight. Also flexible epoxy resin glue is common for damping sound and vibration.
• Aerospace: the aerospace industry uses epoxy adhesives as one component films and 2K epoxy glue systems for various applications. For example helicopter rotor baldes are bonded with epoxy glues due to the adhesives´ extreme strength and mechanical stability.
• Marine: as epoxies form watertight bonds and are resistant to salt water, they are ideal for marine environments.
• Construction: epoxy adhesive is also used in construction for example for repairing floors and tiles. The adhesives are resistant against the elements and therefore, suitable also for outdoor applications. Next to being an industrial adhesive, construction epoxy adhesive is also popular among DIYers.

Tip: for what ever you are using epoxy adhesive, research shows that proper storage of the glue can remarkably improve efficiency.

Find the epoxy adhesive that is a perfect match to your project

As we have now discovered, epoxy glue is not simply one type of adhesive, but covers a wide variety of formulations which all have their advantages. In case you are looking for the best possible industrial epoxy adhesive for your project, contact us and let our experts connect you with the most suitable epoxy resin adhesive.

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