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  • Epoxies

Innovatie en ervaring

Meer dan 700 epoxy systemen beschikbaar van RTM tot bio en van watergedragen tot vlamvertragend. 

Ons leverprogramma epoxies bestaat onder andere uit de formulaties die ontwikkeld zijn door het Franse Resoltech en het Duitse Rampf. Deze formulaties zijn soms ontwikkeld naar aanleiding van de behoefte van hele branch, maar meestal op klantspecieke wensen. Wij leveren vanaf 1kg en kunnen u vanaf het begin tot het eind helpen met uw ontwikkeling. Dankzij onze brede kennis van de epoxymarkt treden wij voor grote bedrijven ook op als intermediair.

We have focused on formulation and polymer engineering, developing over 500 systems while also trading in related materials such as reinforcements, core materials and vacuum disposables. A large number of formulations were invented in partnership with customers to fit a specific application.  Our creativity led us to offer a wide range of epoxy and vinylester products, while also formulating and manufacturing for third party companies. It also led to the creation of very advanced polymers such as water based epoxy systems or fire resistant resins. Low toxicity is another common factor to more and more of our products. Services are an important part of our philosophy, including on-site assistance, structural calculations and infusion simulation.

Algemene info over epoxies

The large family of epoxy resins represent some of the highest performance resins of those available at this time. Epoxies generally out-perform most other resin types in terms of mechanical properties and resistance to environmental degradation, which leads to their almost exclusive use in aircraft components. As a laminating resin their increased adhesive properties and resistance to water degradation make these resins ideal for use in applications such as boat building. Here epoxies are widely used as a primary construction material for high-performance boats or as a secondary application to sheath a hull or replace water-degraded polyester resins and gel coats.

The term 'epoxy' refers to a chemical group consisting of an oxygen atom bonded to two carbon atoms that are already bonded in some way. The simplest epoxy is a three-member ring structure known by the term 'alpha-epoxy' or '1,2-epoxy'. The idealised chemical structure is shown in the figure below and is the most easily identified characteristic of any more complex epoxy molecule.

Usually identifiable by their characteristic amber or brown colouring, epoxy resins have a number of useful properties. Both the liquid resin and the curing agents form low viscosity easily processed systems. Epoxy resins are easily and quickly cured at any temperature from 5°C to 150°C, depending on the choice of curing agent. One of the most advantageous properties of epoxies is their low shrinkage during cure which minimises fabric 'print-through' and internal stresses. High adhesive strength and high mechanical properties are also enhanced by high electrical insulation and good chemical resistance. Epoxies find uses as adhesives, caulking compounds, casting compounds, sealants, varnishes and paints, as well as laminating resins for a variety of industrial applications.

Epoxy resins are formed from a long chain molecular structure similar to vinylester with reactive sites at either end. In the epoxy resin, however, these reactive sites are formed by epoxy groups instead of ester groups. The absence of ester groups means that the epoxy resin has particularly good water resistance. The epoxy molecule also contains two ring groups at its centre which are able to absorb both mechanical and thermal stresses better than linear groups and therefore give the epoxy resin very good stiffness, toughness and heat resistant properties.

The figure below shows the idealised chemical structure of a typical epoxy. Note the absence of the ester groups within the molecular chain.

Epoxies differ from polyester resins in that they are cured by a 'hardener' rather than a catalyst. The hardener, often an amine, is used to cure the epoxy by an 'addition reaction' where both materials take place in the chemical reaction. The chemistry of this reaction means that there are usually two epoxy sites binding to each amine site. This forms a complex three-dimensional molecular structure.

Since the amine molecules 'co-react' with the epoxy molecules in a fixed ratio, it is essential that the correct mix ratio is obtained between resin and hardener to ensure that a complete reaction takes place. If amine and epoxy are not mixed in the correct ratios, unreacted resin or hardener will remain within the matrix which will affect the final properties after cure. To assist with the accurate mixing of the resin and hardener, manufacturers usually formulate the components to give a simple mix ratio which is easily achieved by measuring out by weight or volume.

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