Concentrol develops different solutions in adhesives. It is a division with a transversal vision that produces products for very different sectors.
NETMELT hot-melt adhesives are made from a thermoplastic material that is solid at room temperature and which, due to the action of heat, melts to become a more or less fluid liquid that can be applied to a wide variety of substrates to hold them together.
Said solution is basically formed by polymeric components, resins, waxes of different natures and antioxidants.
They can be applied to a wide range of surfaces, both porous and non-porous, so that the bonds offer great thermal and mechanical resistance. The bond strength between substrates is simply physical and instantaneous, so it does not require any subsequent curing process.
The main sectors of application are: Packaging, closing boxes, cases, paper bags, plastics, binding, book spines, book sides, food, labels, cartons, straws, automotive, construction, tiles, furniture making, mattresses , mattress covers, PU foam, pocket springs, textiles in general, sanitary products, plasters and personal hygiene.
Properties
Each application requires specific properties. Concentrol adapts the hot melt adhesive by modifying the setting speed, the cohesion of the adhesive or the adherence according to surfaces.
Hot melt adhesives are characterized by being thermally stable, although the melts can suffer oxidative deterioration at high working temperatures or with long exposures to temperatures without product flow, for example, if we leave the tank hot over the weekend without working on the production line.
Hot melt adhesives offer different advantages:
- They are free of solvents.
- As they are solid, they are easy to handle, store and transport.
- Immediately after cooling they show a completely solid bond.
- They are stable to aging.
- They have a wide range of applications, given the large number of formulation possibilities and existing properties.
- Very suitable in applications where a high gluing speed is required, always higher than that of cold glues.
- It allows to obtain unions with a magnificent cohesion, but at the same time very elastic.
- Their initial bite at a high application temperature makes them very suitable for gluing plastic sheets.
- Its high performance allows to reduce the production time in industrial applications.
The versatility of this Concentrol product allows additives to be incorporated into the formulation such as pigments to give colour or optical markers visible in ultraviolet light.
Hot melts can be classified into three groups with three distinctive trade names:
The NETMELT PC range is made with an EVA base (ethylene-vinyl-acetate copolymer), and is commonly used due to its cost and wide range of use. This product can be presented in a yellowish colour (cheaper) or a whiter one.
NETMELT PLUS is made with a polyolefin base, having greater thermal stability than conventional EVA-based ones. This product helps keep application equipment cleaner while reducing the need to change filters, nozzles, and other costly items. It is a practically colourless and odourless product, so it is suitable for the packaging of food products.
NETMELT TACK adhesives have high tack, even when cold. They are formulated with a rubber base, have great flexibility at low temperatures and great elongation. Used in pressure sensitive adhesive applications.
Technical characteristics
There are two very important intrinsic parameters of these products to take into account: viscosity and softening point. Both parameters can vary depending on the components that are part of the adhesive, as well as its application.
The viscosity is determined by the force that opposes the product, in liquid state, against the rotation of a disc attached to a shaft that turns at constant speed.
This parameter is inversely related to temperature. Thus, the higher the temperature, the lower the viscosity of the adhesive.
The softening point is the temperature from which the adhesive passes from a solid state to a liquid state, passing through an intermediate phase of thermoplastic behaviour. Hot melt adhesives do not change from a solid to a liquid state at a certain temperature, but rather their consistency progressively decreases as the temperature rises.
Additionally, there are other features related to the application to take into account: tack, adhesion, cohesion, open time, pressure time and set time.
Tack is the stickiness of the adhesive surface.
Adhesion is the bond strength of the adhesive with the substrate.
Cohesion is the internal force that prevails between the molecules of the adhesive to hold them together.
The open time: it is the interval between the application of the adhesive and the assembly. In other words, it is the time available to obtain a satisfactory bond after the adhesive has been applied, during which it maintains its adhesive properties.
The pressure time is the period during which pressure is exerted on the substrates to obtain good contact to facilitate adhesion.
The set time is the minimum time it takes to form a good bond between two substrates and the adhesive.
Concentrol continues in a growth phase, tackling new challenges, but also facing the new needs that may arise in the application sectors. The chemical company puts effort and work so that its solutions adapt to the highest quality standards of its customers.
