Resins are viscous liquids that are cross-linked into hardened structures.
They are often combined with reinforcement materials to form composite structures.
Popular types include polyester, epoxy, vinyl ester and polyurethane resins.
Resin selection depends on the application. In the context of laminating, resins are a core ingredient in composite creation, forming the ‘matrix phase’ whilst glass fibre or carbon fibre forms the ‘reinforcement phase’, ultimately delivering high-strength, lightweight structures. Elsewhere, polyurethane resin may be used to bind aggregate to form a mechanically strong layer used for flooring applications.
Resin Library offers a range of premium, high-performance resins for a range of projects.
Resins are a class of versatile and highly viscous liquids. They can transition into solid, cross-linked structures when mixed with a hardener/catalyst.
Many resins are combined with reinforcement fabrics like glass fibre matting, carbon fibre fabric and aramid fibre to generate strong, lightweight composites. Elsewhere, they are combined with aggregate in flooring applications.
Resin Library offers a range of resins suitable for laminating, moulding and other projects.
Resin selection depends on the type of application that it is intended for.
The true benefits of resin are only full realised when they are combined with reinforcement materials, yielding composite structures. These composites can comprise polyester and glass fibre matting (fibreglass), epoxy resin and carbon-based cloth (carbon fibre) or in the case of resin flooring, polyurethane and aggregate.
The purpose of the resin may also be to form a thin, homogeneous outer layer as part of a multi-layered resin floor or as a final layer to protect a fibreglass structure. In the case of the latter, are typically gelcoats and flowcoats, depending on whether a coating or a moulding is used.
When selecting a resin, it is always best to work backwards from the finished part. If the part is intended to be strong, lightweight and rigid, then a carbon fibre composite would be desirable, necessitating the use of epoxy resin. If a waterproof lining is required to protect concrete, then a fibreglass covering would be desired.
If in doubt, work backwards from what the industry standard is.
Other considerations would be skill level. Whilst we aim to supply as much content as possible to support prospective customers, there is a degree of skill required in the usage of such resins. Laminating with fibreglass and carbon fibre composites can be complex – particularly at larger or more complex scales. In such instances, it is alway wiser to seek professional assistance or, where possible, practice in advance.
Q. What applications is resin used for?
A. Resins are used for coatings, adhesives and ingredients in composite materials.
Q. What is the difference between thermosetting and thermoplastic resins?
A. Whilst both thermoset and thermoplastics are polymer-based materials, there are key differences.
Thermoset Resin
Thermosetting resins: (also known as thermosets), are polymers produced when a liquid pre-polymer undergoes a hardening process to form a solid structure. This process is initiated by a hardener (catalyst) or other factor such as heat, pressure or radiation.
The curing process is irreversible; they cannot be remelted or reformed. Thermosetting resins tend to have high dimensional stability, high-temperature resistance, and good resistance to solvents because of their three-dimensional cross-linked structure.
Thermosetting resins include generic resins such as polyesters, vinyl esters, epoxies, and polyurethanes. Materials added to them are usually termed hardeners, curing agents, peroxide initiators, isocyanates, fillers, and flexibilizers.
These resins are typically used in composite structures like fibreglass (GRP) and carbon fibre.
Thermoplastic Resin
Thermoplastic resins: solid materials which transition soften to liquids at high heat, and then harden again when cooled. Thermoplastic materials can be shaped and moulded into a range of shapes and structures. This makes them ideal for a range of industries.
Thermoplastic resins include polyamides, poly(vinyl alcohol) (PVA), polyethylene, poly(tetrafluoroethylene), poly(vinyl chloride) (PVC), polypropylene, and poly(ether-ether ketone) (PEEK)
The following resins are some of the most commonly used types of thermosets used today.
Epoxy Resin
Epoxy resins have been in use for almost a century, with applications in automotive, aeronautics, construction, and electronics, marine, medical and sports industries.
As isolated materials, they present superior mechanical, chemical properties and their range of applications is further enhanced by the ability to combine them with reinforcements like Kevlar® and carbon fibre to deliver composite structures.
Epoxies are typically grouped into laminating, moulding, coating, casting and infusion resins. It is the subject of much research into curing and composite improvements.
Polyurethane Resin
Polyurethanes are a class of resins produced from the reaction of an isocyanate (typically polymeric isocyanate) with a polyol.
They can exist as elastomers, sealants and elastoplastics (which are high-modulus elastomers).
Their physicochemical properties can be controlled according to the intended application, based on the chemical composition. Their physical state can range from soft foams through to hard tooling materials.
In the context of construction, they are often combined with aggregate for flooring applications to compliment the high mechanical strength of aggregate – and as waterproofing membranes for roofing applications. They have good abrasion resistance, which makes them favourable for industrial applications.
Polyester Resin
Polyester resin (also known as ‘laminating resin’ or ‘fibreglass resin’) is a polymer. Cheaper than other resins, it is a core ingredient in construction and marine industries through to aerospace and automotive.
There are two main types of polyester resin: saturated and unsaturated. The saturated version is less commonly used, whilst unsaturated polyester resin is used for a much wider range of applications, from yachts to flat roofing membranes, pond linings and yacht hulls.
It is often combined with glass fibre reinforcement to create fibreglass (also known as ‘GRP’ – short for glass reinforced polyester).
Vinylester Resin
Vinyl ester resins are manufactured by the esterification of an epoxy resin with acrylic or methacrylic acids.
More expensive than polyester resins, they are used for specialist applications which require certain properties.
Vinyl esters combine favourable properties polyester and epoxy resin, leading to excellent mechanical and chemical properties. They are often combined with glass fibre reinforcement and are an ideal option for a range of industrial environments where enhanced chemical resistance and mechanical strength is required.
The video below shows footage from an SEM (scanning electron microscope) of a glass fibre composite infused with vinyl ester resin.
There are a range of high-quality and informative academic publications available about resins and their applications and performance.
+ Towards Selection Charts for Epoxy Resin, Unsaturated Polyester Resin and Their Fibre-Fabric Composites with Flame Retardants. Materials (Basel). 2021 Mar; 14(5): 1181. Published online 2021 Mar 3. doi: 10.3390/ma14051181.
+ NASA Technical Memorandum. CRITERIA FOR SELECTING RESIN MATRICES FOR IMPROVED COMPOSITE STRENGTH. TECHNICAL PAPER proposed for presentation at Twenty-Eighth Reinforced Plastics/Composites Institute sponsored by the Society of the Plastics Industry Washington, D. C., February 6-9, 1973. by C. C. Chamis, M. P. Hanson, and T. T. Serafini Lewis Research Center.
