Water-based adhesives are actually used everywhere, such as in the packaging industry, woodworking, cardboard processing, lamination, panel construction, utility construction, bookbinding, the graphics industry and so on. Glues are used in the process at many factories, often this is a hot melt or a water-based glue. There are many types of glue, yet water-based glues and hot melts are often used in industrial production processes because of high efficiency and low costs. Most adhesives are designed for specific machine applications, depending on the production method or product requirements. Hot melt adhesives are easy to use in many processes with standard machines, short pressing times or longer machine downtime are no problem for these adhesives. While water-based adhesives are more efficient and can provide stronger bonds, sometimes the advantage is that a water-based adhesive does not add volume to, for example, flat-stacked boxes.
Types of water based glue
There are different water-based adhesives, depending on the application, product or industry, many variations are possible. Water-based adhesives are also still widely used in manual applications, such as wallpaper, floor and construction applications.
What is a water-based adhesive?
Glues should in principle be liquid before application. Traditionally, starch was already dissolved in water. Volatile solvents were later used to accelerate this process. Hot melts become liquid by heating them. Adhesives usually have to be liquid to properly wet a surface, they usually have to flow well in order to get optimally close to the surface in order to exert Van der Waals forces. The purpose of the water is therefore to create a good flow and distribution and after application this “solvent” has to disappear to achieve a final final strength. Most water-based adhesives are synthetic in origin; based on polymers such as PVOH, EVA, and PVAC. There are also vegetable sources such as starch and sugar. Gelatin is also a water-based type of hot melt. The right solution is often in the mix of parameters for application, production method and end product.
How does the water disappear?
In almost all water-based adhesives, the water evaporates through surfaces, in cement-bound adhesives, the added water is part of the reaction to the end product, the water becomes part of the chemical composition of the cement. This is almost never the case with ready-to-use water-based adhesives. With water-based adhesives it is therefore important that at least one of the substrates is porous to absorb the water or allow it to evaporate.
How is a water-based adhesive made?
Intercol uses all kinds of raw materials from industry, there are chemical suppliers of water-based synthetic dispersions, which are supplied in liquid form. Many starches, PVOH and other binders and additives are supplied dry and must be mixed in a specific way and conditions.
Is a water-based adhesive waterproof?
Water-based adhesives can be water-soluble after drying, but can also be very waterproof. Mouth flap adhesives for envelopes are pre-eminently “reactivable” or remoistable, while D4 wood adhesives on a PVAC basis are sufficiently resistant to boiling water after sufficient drying. The base of the glue, UAE, EVA, PVAC, PVOH, casein, dextrin or starch, together with the additives such as crosslinkers, determine the ultimate water resistance.
There are also "ice-water-resistant" adhesives, which are specific adhesives for labeling
Is a water-based adhesive perishable?
Water-based adhesives are different perishable per glue. With synthetic adhesives, the packaging, that part that contains moist air and no glue, can become infected by fungi after a long time. The synthetic glue will usually not be affected. With adhesives based on starch, casein or dextrin, the glue can really spoil itself.
Depending on the product and the permitted preservation, we guarantee the shelf life of the packaging, provided it remains closed.
What different types of water-based adhesive are there?
Most water-based glues are nowadays synthetic, traditionally vegetable-based vegetable glues are still made. Now that environmental aspects, recycling, biodegradable and biobased in them, vegetable based adhesives are getting more attention.
What types of synthetic glue are there?
These are the most commonly used water-based synthetic adhesives:
- PVAC Homopolymers
- Vinyl Acetate Copolymers
- Vinyl Acetate Copolymers
- Styrene / Acrylic Copolymerene
- Acrylic Copolymers
- Terpolymers
What types of vegetable glue are there?
These are the most commonly used water-based vegetable adhesives:
- Potato starch
- Recycle starch (waste products from the agro industry)
- Wheat starch
- Corn starch
- Methyl cellulose glue (wallpaper paste)
- Casein (milk protein)
- Dextrin
- Glucose, Sugar
In addition, other environmentally friendly glues are conceivable, such as gelatin, protein glue, collagen glues, gum resin or latex from the rubber tree. These glues are not always pure vegetable or good compostable.
Special properties of some of these vegetable and environmentally friendly adhesives
Not all vegetable raw materials are suitable for making industrially applicable adhesives, this strongly depends on the specific application.
Starch and dextrin glues
Zetmeer and dextrin glues are well-known types of vegetable glue, these are already widely used for applications such as
- wallpaper paste, wall coverings
- papermaking, corrugated board, pulp board, paper glue
- traditional bookbinding
- labeling of cardboard, paper and glass, and all-round labeling on labeling machines
Starch adhesives are usually almost entirely biobased, biodegradable and compostable. They are probably the most harmless environmentally friendly types of glue. By applying food-safe additives, Intercol can further formulate this promising raw material in order to meet the machine properties as well as possible.
Casein adhesives
Casein glues are based on animal protein, which is mainly obtained from cow's milk. In terms of raw material, it competes largely with protein as used in whey products. Casein glues are still used in:
- Labeling of glass; preservative paints, soft drinks, & beer
- The production of shoes
- Manual Cardboard and paper applications
Important properties of Casein glues are the high tack (syrupiness) and steep viscosity curve. In addition, these glues can be set quite easily, which is sometimes a requirement for labeling beer bottles. On the other hand, casein glues can dissolve well in water baths when reusing return bottles.
Special properties of a number of water-based synthetic adhesives
Water-based synthetic adhesives range from water-thin liquid form to pastes and sealants. In particular water thin to paste-like products are used industrially. Many sealants in industrial automated applications can be blurred by a assembly hot melt.
PVAC adhesives
PVAC glues are the best known, and one of the oldest types of synthetic glue. This raw material mainly serves wood applications, cardboard and paper applications. Many D2 and D3 wood glues are examples of a pure PVAC glue. By formulating with this raw material, the adhesion can be improved and the water solubility can be improved or the water resistance can be set higher.
Copolymer vinyl acetate adhesives
This copolymer glue can be seen as a modern, improved PVAC ljim. In addition to polyvinyl acetate (PVA), ethylene vinyl acetate (EVA) is used to produce these dispersions. The water-based mixture is white in itself, after applying and drying the adhesive a clear, flexible connection is created that is also suitable for all kinds of applications such as paper, wood and plastic. Copolymer adhesives are widely used for the production of packaging, such as for use in the food industry.
Acrylate dispersion adhesives
Acrylates are used for specific markets and can sometimes serve as an adhesion promoter in formulated formulations. The standard dispersion acrylates dry like a normal water-based adhesive. However, there are also many other adhesives based on acrylic.
Acrylic dispersions are usually relatively environmentally friendly adhesive systems. Typical applications with acrylics:
- Production of self-adhesive materials such as tape and self-adhesive foil
- Making foam materials adhesive
- As an adhesive for plastic materials and some rubbers
